Data from the Liverpool TDM (therapeutic drug monitoring) Registry were linked with the UK Collaborative HIV Cohort (CHIC) study. For each patient, the first measurement of lopinavir (twice daily) or atazanavir [once daily, ritonavir boosted (/r) or unboosted] plasma concentration was included. Linear regression was used to evaluate the association of dose, gender, age, weight, ethnicity and concomitant antiretroviral drugs or rifabutin with log-transformed drug concentration, adjusted for time since last intake.

Data from 439 patients on lopinavir (69% 400 mg/r, 31% 533 mg/r; 3% concomitant rifabutin) and 313 on atazanavir (60% 300 mg/r, 32% 400 mg/r, 8% 400 mg) were included. Multivariable models revealed the following predictors for lopinavir concentration: weight (11% decrease per additional 10 kg; P = 0.001); dose (25% increase for 533 mg/r; P = 0.024); and rifabutin (116% increase; P < 0.001). For atazanavir the predictors were dose (compared with 300 mg/r: 40% increase for 400 mg/r, 67% decrease for 400 mg; overall P < 0.001) and efavirenz (32% decrease; P = 0.016) but not tenofovir (P = 0.54).

This analysis confirms that efavirenz decreases atazanavir concentrations, and there was a negative association of weight and lopinavir concentrations. The strong impact of rifabutin on lopinavir concentration should be studied further.

The C. albicans CAI-4 strain carrying transcriptional fusions of the TRR1p, YHB1p and GRE2p genes to the Renilla reniformis luciferase LUC gene was pre-treated with subinhibitory concentrations of fluconazole and incubated with oxidants (diamide and hydrogen peroxide) or with the myelomonocytic cell line HL-60.

Fluconazole induced oxidative and nitrosative stress in a time- and dose-dependent manner as determined using oxidative- and nitrosative-specific gene reporters. At subinhibitory concentrations, fluconazole was able to induce protection in vitro to subsequent challenges with oxidants in both liquid and solid media, and also induced partial protection against the oxidative-mediated killing mechanisms of the myelocytic HL-60 cells.

Subinhibitory concentrations of fluconazole protect against oxidants and killing mediated by phagocytes.

A neutralization test was applied as a screening assay and a plaque reduction assay was used for confirmation. Expression plasmids for viral ribonucleoproteins (RNPs) and a plasmid that allowed expression of a pseudoviral reporter RNA were transfected into cells to investigate the effects of a novel antiviral compound on viral RNA synthesis.

BPR2-D2 was identified as a novel inhibitor against influenza virus from a hit obtained from high throughput screening of 20 000 or more compounds. BPR2-D2 exhibited an excellent antiviral efficacy for the oseltamivir-resistant virus (EC₅₀ ranging from 0.021 to 0.040 µM). No resistant virus was produced throughout 20 passages in the presence of BPR2-D2, whereas oseltamivir-resistant virus was generated at passage 8 using the same experimental system. A molecular target other than neuraminidase (NA) was found because BPR2-D2 inhibited the synthesis of viral RNA that was driven by influenza viral RNP in a transfection assay. BPR2-D2 also exhibited a broad antiviral spectrum against various strains of influenza A and influenza B viruses.

BPR2-D2 was identified as a novel inhibitor of influenza virus. It may target viral RNPs that are responsible for viral RNA synthesis. Targeting different molecules compared with NA allows BPR2-D2 to inhibit oseltamivir-resistant viruses.

The killing kinetics of XF-70, XF-73 and various comparator agents against exponential phase cultures of S. aureus SH1000 were compared with effects on cells held at 4°C, non-growing cultures expressing the stringent response induced by mupirocin and bacteria in the stationary phase. Biofilms of S. aureus SH1000 were generated with the Calgary device to examine the activities of XF-70 and XF-73 under a further system exhibiting diminished bacterial growth.

Cold culture, stringent response and stationary phase cultures remained susceptible to XF-70 and XF-73, which caused ≥5 log reductions in viability over 2 h. During this period the most active comparator agents (chlorhexidine and cetyltrimethylammonium bromide) only promoted a 3 log drop in viability. XF-70 and XF-73 were also highly active against biofilms, with both agents exhibiting low biofilm MICs (1 mg/L) and minimum biofilm eradication concentrations (2 mg/L).

XF-70 and XF-73 remained highly active against various forms of slow-growing or non-dividing S. aureus. The results support the hypothesis that membrane-active agents may be particularly effective in eradicating slow- or non-growing bacteria and suggest that XF-70 and XF-73 could be utilized to treat staphylococcal infections where the organisms are only dividing slowly, such as biofilm-associated infections of prosthetic devices.

One thousand four hundred and forty M. catarrhalis isolates originating from seven world regions were investigated. The isolates were recovered from 411 children <5 years of age and 1029 adults >20 years of age. PCR-restriction fragment length polymorphism (RFLP) was performed to determine bro prevalence and to distinguish between bro types. MIC values of 12 different antibiotics were determined using the CLSI (formerly NCCLS) broth microdilution method.

Of the 1440 isolates, 1313 (91%) possessed the bro-1 gene and 64 (4%) possessed the bro-2 gene. Additionally, the prevalence of bro positivity between the child and adult age groups was significantly different (P < 0.0001), though bro-1 and bro-2 prevalences within age groups were not significantly different. Consistently higher β-lactam MICs were observed for M. catarrhalis isolates originating in the Far East. Significant correlations in MICs were observed for several antibiotic combinations, including all five β-lactams with each other, and among the two quinolones.

The worldwide prevalence of bro gene carriage in clinical isolates of M. catarrhalis is now approaching 95%, with children significantly more likely to harbour bro-positive isolates than adults. Further, statistically significant differences in the distribution of β-lactam MICs were observed between different world regions, particularly with respect to the Far East.

Laboratory-derived S. aureus strains were generated under selection using a variety of cell-wall-active antibiotics. Complete sequences of 27 genes, including 17 two-component histidine kinase sensors, were then compared with those of their susceptible parent strain. Further genetic analysis was performed on 125 clinical S. aureus isolates and 42 geographically diverse isolates of vancomycin-intermediate S. aureus (VISA).

Selective pressure using imipenem resulted in single point mutations leading to amino acid substitutions in two genes: vraS, encoding a two-component histidine kinase sensor; and SA1702 (also called yvqF, located immediately upstream of vraS), encoding a conserved hypothetical protein. The accumulation of the mutation in two distinct proteins—MsrR, a peptide methionine sulphoxide reductase regulator, and TcaA, a teicoplanin-resistance-associated protein—correlated with further increases in the glycopeptide MIC. The prevalence of YvqF/VraSR mutants among 125 clinical isolates along with the corresponding teicoplanin MICs was as follows: 0% (0/39), ≤1 mg/L; 48.6% (17/35), 2 mg/L; 72.7% (24/33), 4 mg/L; 93.8% (15/16), 8 mg/L; and 100% (2/2), 16 mg/L. Genetic analysis of 42 VISA isolates also identified the predominant amino acid substitutions in YvqF/VraS: 9 isolates (21.4%) revealed mutations in YvqF, followed by 7 isolates with mutations in VraS (16.7%).

Our findings provide novel insights into the high prevalence and genetic diversity of YvqF/VraSR mutants among clinical S. aureus isolates with reduced susceptibility to teicoplanin.

In an earlier randomized, double blind study of liposomal amphotericin as initial therapy for invasive filamentous fungal infection (IFFI), a 3 mg/kg/day dose had a favourable overall response rate of 50% and 12 week survival rate of 72%. No improved outcome was seen with 10 mg/kg/day for the first 14 days. The study population was further analysed for the effect of prior azole exposure on treatment responses to liposomal amphotericin B. The protocol allowed prior treatment with azoles for prophylaxis or empirical therapy, and for up to 4 days for the confirmed IFFI before starting liposomal amphotericin B. Outcomes were compared for subsets of patients based on receipt of any azole and receipt of voriconazole during the 30 day screening period prior to study treatment.

Of 201 patients with data review board-confirmed IFFI, 116 (57.7%) received prior azoles and 36 (17.9%) received prior voriconazole. Favourable responses were achieved in 57 (49.1%) patients with prior azole exposure, in 39 (45.9%) without prior azole and in 13 (36.1%) with prior voriconazole. Numbers of patients alive at 12 weeks were 74 (63.8%) with any prior azole, 56 (65.9%) without prior azole and 26 (72.2%) after prior voriconazole. No differences were statistically significant.

Prior treatment with any azole or specifically with voriconazole did not seem to impact on overall response or survival in patients treated with liposomal amphotericin B for confirmed IFFI.

PVL-MRSA from community-based and hospitalized patients located across England were identified by PCR. Isolates were characterized via MIC determinations, toxin gene profiling, PFGE, SCCmec, spa and agr typing. Multilocus sequence typing (MLST) was performed on selected isolates. Patient demographic and available disease data were retained for analysis.

Seventy-six PVL-MRSA isolates resistant to three further classes of antibiotic were identified between 2005 and 2008 from centres in each of the Health Protection Agency's geographic regions in England. Patient demographics were typical for PVL-MRSA, and some travel associations were identified along with clonal spread. One instance of familial transmission in the community was detected. PVL-MRSA belonging to MLST clonal complex (CC) 1 (sequence type 772) were consistently highly resistant; multiply antibiotic-resistant representatives of CCs 5, 8, 22, 59 and 80 were also identified. Ciprofloxacin resistance was common amongst the study isolates (51 of 76 isolates).

Genetically diverse multiply antibiotic-resistant PVL-MRSA were identified, and included representatives of a recently emerged multiresistant clone (dubbed the Bengal Bay clone). Risk factors and disease presentations were typical for PVL-MRSA infections. This work highlights the diminishing utility of ciprofloxacin susceptibility for putative identification of PVL-MRSA.

Electronically prescribed doses of systemic antibacterials administered in this trust during 2008 were analysed in order to generate 10 indices of antimicrobial use for each of 14 departments. These indices were five measurements of consumption (DDDs, agent days, courses, antibiotic days and treatment periods) each denominated by two measurements of activity [bed days and finished consultant episodes (FCEs)].

The 10 indices cluster into four groups within which they correlate well but between which correlation is poor. These four groups comprise a volume-related measurement of consumption (DDDs, agent days, antibiotic days) and an exposure-related measurement of consumption (courses, treatment periods), each denominated by either bed occupancy (bed days) or patient throughput (FCEs).

Indices within these four groups seem to provide different and complementary information. Restricting measurement of antimicrobial use to a single metric such as DDDs per 1000 bed days may be insufficient. It is not known which (if any) of these indices are the best predictors of antimicrobial-related risks such as resistance pressure or Clostridium difficile infection.

PMOs with identical 11-base sequence (AcpP) targeted to acpP (an essential gene) of Escherichia coli were synthesized with various numbers of either piperazine (Pip) or N-(6-guanidinohexanoyl)piperazine (Gux) coupled to the phosphorodiamidate linker. Peptide–PMO conjugates were made using the membrane-penetrating peptide (RXR)₄XB (X is 6-aminohexanoic acid; B is β-alanine).

MICs (µM/mg/L) were measured using E. coli: 3 + Pip–AcpP, 160/653; 6 + Pip–AcpP, 160/673; 2 + Gux–AcpP, 20/88; 5 + Gux–AcpP, 10/49; 8 + Gux–AcpP, 10/56; 3 + Pip–AcpP–(RXR)₄XB, 0.3/2; and 5 + Gux–AcpP–(RXR)₄XB, 0.6/4. In cell-free protein synthesis reactions, all PMOs inhibited gene expression approximately the same. These results suggested that Pip–PMOs inefficiently penetrated the outer membrane. Indeed, the MICs of 3 + Pip–AcpP and 6 + Pip–AcpP were reduced to 0.6 and 2.5 µM (1.2 and 10.5 mg/L), respectively, using as indicator a strain with a ‘leaky’ outer membrane. In vivo, mice were infected intraperitoneally with E. coli. Intraperitoneal treatment with 50 mg/kg 3 + Pip– AcpP, 15 mg/kg 5 + Gux–AcpP or 0.5 mg/kg 3 + Pip–AcpP–(RXR)₄XB, or subcutaneous treatment with 15 mg/kg 5 + Gux–AcpP or (RXR)₄XB–AcpP reduced bacteria in blood and increased survival.

Cationic PMOs inhibited bacterial growth in vitro and in vivo, and Gux–PMOs were more effective than Pip–PMOs. However, neither was as effective as the equivalent PMO–peptide conjugates. Subcutaneous treatment showed that 5 + Gux–AcpP or (RXR)₄XB–AcpP entered the circulatory system, reduced infection and increased survival.

The gp120-interacting plant lectin HHA (‘Hippeastrum hybrid agglutinin’), the non-nucleoside reverse transcriptase inhibitor KRV2110 and the fusion inhibitor enfuvirtide (T20) were combined in 12 drug associations by using the Ray combination design method. Their activity against HIV-1_BaL was assessed by the lymphocyte infectivity reduction assay and by the single-cycle BaL pseudovirus (PV) assay. In addition, their cell tolerance was evaluated for HEC-1 and HeLa epithelial cell lines, both originating from genital tissue.

All evaluated combinations showed synergistic activity in both lymphocyte infectivity reduction and single-cycle BaL PV assays. The combination HHA + KRV2110 resulted in the highest cell viability, whereas the combinations including T20 exhibited a dose-dependent decrease in cell viability, demonstrating the differential tolerance of epithelial cell lines to the combinations.

These observations provide a rational basis for in vitro testing of microbicide candidate molecule combinations, including anti-HIV-1 and cytotoxic cellular assays.

Multivariable models were developed to describe macrolide defined daily doses per capita.

Use was highest during October to March for all macrolides. Investigated yearly and provincial patterns differed considerably among the macrolide agents. Associations with socioeconomic variables were similar between clarithromycin and erythromycin, while azithromycin consumption showed some differences in its association with these variables. Consistently, the rate of influenza was significantly associated with increased macrolide use. The influenza rate interacted with socioeconomic variables in some models; as the influenza rate increased, the greatest increase in demand for macrolides occurred in populations with high percentages of low-income individuals, high unemployment levels and low percentages of individuals with bachelor's degrees.

The impact of associations among macrolide consumption, influenza and socioeconomic factors may reflect inappropriate use of these agents to treat viral infections and/or prescribing for secondary infections, and knowledge of the virus versus bacteria problem and accessibility of healthcare. Further research surrounding differences in access to antimicrobial prescriptions and treatment options between advantaged and disadvantaged populations is suggested to further understand the dynamics of antimicrobial use in Canada.

Sixty-two B. melitensis strains, isolated from humans—most experiencing their first brucellosis episode—over an 11 year period in Spain, were genotyped by multiple locus variable analysis (MLVA-16) for future studies. In the present work, molecular screening was undertaken to detect the presence of rpoB and gyrA/gyrB/parC/parE mutations (previously described in in vitro Brucella spp. mutants) related to resistance to rifampicin and fluoroquinolones, respectively.

Sixty-two MLVA-16 genotypes were identified among the B. melitensis population, with genetic similarity values ranging from 32% to 94%. rpoB mutations related to rifampicin resistance (positions 154, 526, 536, 539, 541, 574) were not detected. Neither were changes in GyrA described in in vitro mutants (67, 71, 87, 91 and an insertion at 340) detected in these strains. All showed identical GyrA, GyrB, ParC and ParE sequences with respect to B. melitensis 16M, except for one strain (ciprofloxacin and moxifloxacin MICs 0.25–0.50 mg/L) that harboured the Val264Ala replacement outside the GyrA quinolone resistance-determining region (QRDR); no differences were seen, however, in the NorMI/II efflux pump genes.

The absence of rpoB mutations clearly related to rifampicin resistance in clinical B. melitensis strains reinforces the first-choice status of this antibiotic in the treatment of first brucellosis episodes, and demonstrates the usefulness of molecular screening for resistant genotypes. The absence of topoisomerase II–IV mutations, however, cannot rule out fluoroquinolone resistance due to the interplay of different mechanisms.

Three hundred and fifteen isolates of Pseudomonas aeruginosa were submitted for testing. MICs of 14 antimicrobials were determined using the Etest and the results categorized using CLSI guidelines. Usually, six antimicrobial pairs were tested in combination also using the Etest. The results were assessed using the fractional inhibitory concentration index (FICI) and also by a novel parameter, the SBPI.

Some 4173 MICs and 1663 combination pairs were performed. The most active individual antimicrobials were colistin, tobramycin and amikacin, with 84%, 69% and 32% of isolates susceptible, respectively. Twenty-eight of 44 antimicrobial combinations were tested >10 times. Of the combinations, 3.6% were synergistic (FICI ≤ 0.5) and 0.1% were antagonistic (FICI > 4.0). Amikacin + ceftazidime (17%), ciprofloxacin + ceftazidime (12.9%) and ciprofloxacin + piperacillin/tazobactam (12%) were the most synergistic combinations. By median SBPI, the most effective combinations in vitro were colistin + ticarcillin/clavulanate, colistin + piperacillin/tazobactam and colistin + meropenem.

The Etest is a useful tool for determining MICs and testing antimicrobial combinations. The SBPI is more discriminatory than the FICI, allowing easy ranking of the combinations, and is likely to have clinical relevance.

Adjuvant activity of plant phenolics was tested using growth inhibition assays in combination with subinhibitory concentrations of novobiocin. The antibacterial susceptibilities of susceptible and MDR A. baumannii to a variety of antibiotics were determined in the absence and presence of ellagic and tannic acids. The effect of the adjuvants on bacterial outer membrane function was examined by using the fluorescence dye 1-N-phenylnaphthylamine (NPN). The efflux pump inhibition was measured by the intracellular accumulation of ethidium bromide (EtBr) and pyronin Y.

At 40 µM, ellagic and tannic acids enhanced the activity of novobiocin, coumermycin, chlorobiocin, rifampicin and fusidic acid against A. baumannii. There were no increases in the uptake of NPN or in the accumulation of EtBr after strains were treated with these adjuvants; however, the intracellular accumulation of pyronin Y by the treated cells was significantly increased, suggesting that ellagic and tannic acids act as efflux pump inhibitors.

Susceptibility of MDR A. baumannii to a variety of antibiotics was enhanced in the presence of ellagic and tannic acids. The use of such plant compounds might provide effective treatments for resistant Gram-negative bacterial infections.

Adults with proven or probable IA, defined strictly according to EORTC-MSG criteria, were eligible. Those with possible IA were enrolled, but were not evaluable for efficacy unless upgraded to proven/probable disease within 7 days of registration based on investigations performed within 48 h after enrolment. Caspofungin dosage was 70 mg (day 1) followed by 50 mg/day. The primary endpoint was the proportion of patients with complete or partial response at the end of caspofungin therapy in the modified intention to treat (MITT) group; secondary endpoints were response and survival at day 84 and safety.

In the MITT group (n = 61), 75% of patients had cancer not in remission (relapsing or refractory), 85% were neutropenic at enrolment and 49% had a Karnofsky score of ≤50. At end of treatment, 1 and 19 patients had complete and partial response, respectively [success rate 33% (20/61)], 9 (15%) achieved stabilization and 31 (51%) had disease progression. One patient was not evaluable. The 6 and 12 week survival rates were 66% (40/61) and 53% (32/60), respectively. Baseline characteristics associated with survival at day 84 were an underlying disease in remission (not relapsing or refractory) and Karnofsky score. Recovery from neutropenia at the end of treatment was also significantly associated with survival. No serious drug-related adverse events or discontinuations due to drug-related adverse events were observed.

Caspofungin provided an observed response rate compatible with the null hypothesis of a true response rate of ≤35%. Underlying disease-related factors had a major impact on results.

A case note review of 1122 patients with 1188 episodes of HIV-associated PCP from three observational cohorts in Copenhagen, London and Milan, between 1989 and 2004, was conducted.

Trimethoprim/sulfamethoxazole (962 PCP episodes, 81%) was the most frequently used first-line therapy, followed by intravenous pentamidine (87 episodes, 7%), clindamycin/primaquine (72 episodes, 6%) and ‘other’ (atovaquone, dapsone/pyrimethamine, trimetrexate or inhaled pentamidine; 67 episodes, 6%). Rates of unchanged therapy were trimethoprim/sulfamethoxazole = 79%, clindamycin/primaquine = 65% and pentamidine = 60% (P < 0.001). First-line therapy was changed because of failure in 82 (7%) episodes and because of toxicity in 198 (17%) episodes. Three month survival rates were trimethoprim/sulfamethoxazole = 85%, clindamycin/primaquine = 81% and pentamidine = 76% (P = 0.09). After adjustment for possible confounders, pentamidine was associated with a significantly greater risk of death at 3 months [hazard ratio (HR) = 2.0, 95% confidence interval (CI) = 1.2–3.4]. Second-line therapy survival rates differed: trimethoprim/sulfamethoxazole = 85%; clindamycin/primaquine = 87%; and pentamidine = 60% (P = 0.01). Multivariable time-updated Cox regression analysis showed a greater risk of death associated with pentamidine (HR = 3.3, 95% CI = 2.2–5.0), but not for clindamycin/primaquine, when both were compared with trimethoprim/sulfamethoxazole.

Pentamidine was associated with a greater risk of death when used as first- and second-line therapy for HIV-associated PCP, and was associated with more treatment changes. Clindamycin/primaquine appeared superior to pentamidine as second-line therapy for PCP in patients failing or developing toxicity with trimethoprim/sulfamethoxazole. In patients failing first-line treatment with non-trimethoprim/sulfamethoxazole regimens, second-line therapy should be trimethoprim/sulfamethoxazole.

Killing curves (final inoculum: 1.0–5.0 x 10⁷ cfu/mL) were performed with 0.88 mg/L final concentrations (serum C_max after a 100 mg 1 h infusion) in Mueller–Hinton broth supplemented with Ca²⁺ and Mg²⁺ (MH) and in MH with 4 g/dL human albumin. Controls were curves in MH with concentrations similar to the free fraction (fC_max = 0.17 mg/L) calculated using protein binding. Activity was measured as log₁₀ initial inoculum reduction (log₁₀ initial inoculum–log₁₀ at 12 h/24 h). Target strains (tigecycline MIC/MBC; mg/L) were: methicillin-resistant Staphylococcus aureus heteroresistant to vancomycin (0.12/0.25); Enterococcus faecium (0.12/0.25); Escherichia coli producing extended-spectrum β-lactamase (0.12/0.25); and Acinetobacter baumannii (0.25/1).

At 24 h the fC_max produced mean decreases of ≤0.1 cfu/mL for all strains, in contrast to the bactericidal activity (mean >3 log₁₀ reduction) provided by C_max concentrations in the presence or absence of albumin for E. coli and E. faecium, and an activity nearly bactericidal for S. aureus (mean ~2.8 log₁₀ reduction). In the case of the A. baumannii isolate the C_max in the presence or absence of albumin produced a mean reduction of 2.56 log₁₀ cfu/mL at 12 h (time of one dosing interval), with a bacteriostatic profile when considering 24 h colony counts (similar counts at 0 and 24 h).

Correcting the total concentration for the reported literature binding values is unreliable since tigecycline antibacterial activity was greater than that suggested by the free fraction of the drug.

Fifty-one staphylococci from Washington State beaches were characterized using antimicrobial susceptibility testing, carriage of acquired tetracycline and/or macrolide resistance genes, staphylococcal cassette chromosome mec (SCCmec) typing, the BBL Crystal^TM Gram-Positive ID System and/or 16S rRNA sequencing, coagulase test and multilocus sequence typing (MLST) for MRSA.

Five multidrug-resistant MRSA SCCmec type I, of which three were MLST type ST45, one ST59 and one a new MLST type, ST1405, plus one susceptible non-typeable (NT) MRSA ST30 were characterized. Thirty-three MRCoNS isolates, representing 21 strains from 9 Staphylococcus spp., carried a range of SCCmec types [I (2), II (6), III (3), V (2), I/II (1) and NT (7)] and varied in their antibiotic susceptibility to other antibiotic classes and carriage of acquired tetracycline/macrolide resistance gene(s). MRSA and MRCoNS donors co-transferred tet(M) and erm(A) genes to an Enterococcus faecalis recipient at a frequency of 10^–8.

This is the first report of MRSA and MRCoNS isolated from marine water and intertidal beach sand. The MLST types and antibiotic carriage of five MRSA isolates were similar to hospital MRSA isolates rather than US community-acquired MRSA isolates. Our results suggest that public marine beaches may be a reservoir for transmission of MRSA to beach visitors as well as an ecosystem for exchange of antibiotic resistance genes among staphylococci and related genera.

Data were collected during a 7 year surveillance period (2001–07) from volunteer surgery wards participating in the INCISO Surveillance Network in Northern France. Main SAP practices, i.e. antibiotic choice, timing of first dose and total SAP duration, were evaluated and compliance checked based on French recommendations. The study focused on selected procedures in digestive, orthopaedic, gynaecological and cardiovascular surgery, for which standard SAP is recommended. Multilevel logistic regression analysis (a two-level random effect model) was carried out to identify SAP-, patient- and procedure-specific factors associated with SSI.

Of 8029 patients who underwent the selected surgeries, 91.3% received SAP and 2.5% developed SSI. Among those receiving SAP, 83.3% received appropriate antibiotic agents and 76.6% had an optimal timing of administration. SAP duration was considered to be appropriate in 35.0%, too long (SAP unnecessarily prolonged) in 45.2% and too short (lack of intra-operative redosing when recommended) in 19.8%. In the multivariate analysis, a too-short SAP duration remained the only inappropriate practice associated with higher SSI risk (odds ratio = 1.8, 95% confidence interval: 1.14–2.81), after adjustment for surgery procedure group, the National Nosocomial Infections Surveillance System risk index, age and infection risk variability among hospitals. No significant relationships were observed between SSI and the other SAP parameters.

A too-short SAP duration was the most important SAP malpractice associated with an increased risk of SSI. Information directed at practitioners should be reinforced based on standard recommendations.

Erythromycin resistance determinants were screened by PCR. The population structure, including multilocus sequence typing, was analysed by using quantitative clonal diversity (diversity ratio, Simpson, Selander–Levin and Shannon mathematical indexes).

The leading resistance gene was erm(B) (74.3% of the isolates), followed by the erm(B) plus mef(A) combination (17.9%) and mef(A) alone (7.7%). The most frequent serotypes were 14 (18%), 19A (15.4%) and 6B (11.5%). A polyclonal structure was detected in resistant strains, including the Spain^9V-3, Spain^6B-2 and Denmark¹⁴-32 international clones. Both genetic diversity and genetic distribution were high, particularly among clones containing erm(B) and erm(B) plus mef(A) determinants.

The resistance determinants erm(B) and the combination of erm(B) plus mef(A) were observed within multiple S. pneumoniae bacteraemic clones. The preservation of a polyclonal structure might provide a suitable background for further evolution of antibiotic resistance.

MICs and minimum bactericidal/fungicidal concentrations were determined for each microorganism grown in suspension and biofilm using microbroth dilution and ATP bioluminescence, respectively. Chequerboard assays were used to determine synergistic, indifferent or antagonistic interactions between CHG and EO or 1,8-cineole.

Antimicrobial activity was demonstrated by CHG, EO and 1,8-cineole; however, CHG was significantly more active against microorganisms in both planktonic and biofilm modes of growth (P < 0.05). Crude EO was significantly more efficacious against microorganisms grown in suspension compared with 1,8-cineole (P < 0.05). Synergistic activity was demonstrated between CHG and both EO and 1,8-cineole against suspensions of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Escherichia coli and Candida albicans, and biofilm cultures of MRSA and Pseudomonas aeruginosa.

In conclusion, CHG may be combined with either crude EO or its major component 1,8-cineole for enhanced, synergistic antimicrobial activity against a wide range of microorganisms in planktonic and biofilm modes of growth; however, the superior antimicrobial efficacy associated with crude EO alone, compared with 1,8-cineole, favours its combination with CHG.

MICs of nemonoxacin were determined for 798 recently collected (2005–07) and non-duplicate isolates of Gram-positive cocci by the agar dilution method. These isolates included: methicillin-susceptible Staphylococcus aureus (MSSA; n = 100); methicillin-resistant S. aureus (MRSA), including ciprofloxacin-susceptible (n = 50), ciprofloxacin-resistant (n = 100), vancomycin-intermediate (n = 50) and daptomycin-non-susceptible (DNS-MRSA; n = 5) isolates, and community-acquired MRSA (CA-MRSA; n = 101); invasive Streptococcus pneumoniae isolates (n = 150); levofloxacin-non-susceptible (MICs of 4–64 mg/L) S. pneumoniae isolates (n = 30); and enterococci (n = 212), including vancomycin-resistant enterococci (VRE; n = 112).

Nemonoxacin had potent activity against MSSA (MIC₉₀ of ≤0.03 mg/L), ciprofloxacin-susceptible MRSA (MIC₉₀ of ≤0.03 mg/L) and CA-MRSA (MIC₉₀ of 0.06 mg/L). For all invasive S. pneumoniae isolates, the activity of nemonoxacin (MIC₉₀ of 0.06 mg/L) was similar to that of gemifloxacin and much better than that of levofloxacin (MIC₉₀ of 2 mg/L) and moxifloxacin (MIC₉₀ of 0.25 mg/L). Nemonoxacin had a 32- to 64-fold higher activity than levofloxacin against levofloxacin-non-susceptible isolates. Nemonoxacin exerted limited activity against ciprofloxacin-resistant MRSA (MIC₉₀ of 1 mg/L), vancomycin-intermediate MRSA (MIC₉₀ of 2 mg/L), DNS-MRSA (MIC₉₀ of 1 mg/L), vancomycin-susceptible enterococci (MIC₉₀ of 2 mg/L for Enterococcus faecalis and 4 mg/L for Enterococcus faecium) and VRE (MIC₉₀ of 4 mg/L for E. faecalis and 16 mg/L for E. faecium).

Our findings point to a potentially useful role for nemonoxacin in the treatment of infections caused by MSSA, ciprofloxacin-susceptible MRSA and S. pneumoniae with various resistance phenotypes.

Mutants defective in genes encoding oxidative stress defence activities were tested by time–kill curves for their contribution to antibiotic tolerance in comparison with the E. faecalis JH2-2 wild-type (WT).

In killing assays, WT cultures lost 0.2 ± 0.1 and 1.3 ± 0.2 log₁₀ cfu/mL after 24 h of vancomycin or penicillin exposure, respectively. A deletion mutant of the superoxide dismutase gene (sodA) exhibited a lack of tolerance as cultures lost 4.1 ± 0.5 and 4.8 ± 0.7 log₁₀ cfu/mL after 24 h of exposure to the same drugs. Complementation of sodA re-established the tolerant phenotype. Bacterial killing was an oxygen-dependent process and a model is presented implicating the superoxide anion as the mediator of this killing. As predicted from the model, a mutant defective in peroxidase activities excreted hydrogen peroxide at an elevated rate.

SodA is central to the intrinsic ability of E. faecalis to withstand drug-induced killing, and the superoxide anion seems to be the key effector of bacterial death.

Twenty-seven isolates were analysed by PCR and sequencing to identify the genes responsible for the β-lactamase resistance phenotypes. The transferability of the phenotypes was tested by conjugation to Escherichia coli K12J53, plasmid detection with S1-PFGE, hybridization and PCRs of the transconjugants. The genetic relationship was determined by PFGE.

We found bla_CTX-M-9 and bla_CTX-M-10 in Salmonella Virchow PT19. bla_CTX-M-14 was detected in Salmonella (IV) 44:z₄,z₂₃:-, Salmonella Enteritidis PT6a, Salmonella Typhimurium DT193 and Salmonella Typhimurium DT104B. bla_CTX-M-1 was found in Salmonella Litchfield. bla_CTX-M-15 and bla_CTX-M-32 were found in Salmonella Enteritidis PT1. bla_SHV-12 was found in Salmonella Blockley, Salmonella Hadar PT2, Salmonella Enteritidis PT21, Salmonella Enteritidis PT1 and Salmonella Bredeney. bla_SHV-2 was found in Salmonella Livingstone. bla_CMY-2 was detected in Salmonella Bredeney, Salmonella Newport, Salmonella Enteritidis PT5b and Salmonella Heidelberg. bla_DHA-1 was detected for the first time in Spain in Salmonella Newport. One strain of Salmonella Senftenberg harboured two extended-spectrum β-lactamases, bla_SHV-12 and bla_CTX-M-9. We have found a large variety of β-lactamase families as well as several members of major relevance, such as CTX-M-15, CTX-M-32, CMY-2 and DHA-1. XbaI-PFGE, conjugation assays and S1-PFGE hybridization showed that all these β-lactamases were mediated by plasmids.

This study demonstrates the emergence of a public health risk related to resistance to β-lactams in Salmonella. The resistance trends need to be monitored carefully.

The efficacy of the combination, evaluated by measuring lesion size and parasite burden in the skin and spleen, was assessed in BALB/c mice infected by L. (L.) major. Miltefosine was administered orally at 25 mg/kg/day for 10 days, while 10% paromomycin gel was applied topically twice a day for 10 days.

Treatment of the experimentally infected animals with topical paromomycin + oral miltefosine combination induced a statistically significant reduction in lesion size and parasite burden in the skin, with complete healing of ulcers, as compared with those treated with oral miltefosine or placebo. Furthermore, topical paromomycin + oral miltefosine combination was as effective as topical paromomycin alone to reduce the lesion size and parasite load in lesions. However, the efficacy of the combination was significantly higher than that observed for the other treatments, including topical paromomycin alone, in reducing the parasite burden in spleen.

The combination of topical paromomycin gel and oral miltefosine provides an enhanced efficacy in the treatment of L. (L.) major-infected mice, thus presenting a significantly higher activity than that observed for the monotherapeutic regimens.

GusA, a well-established reporter gene in other systems, was cloned into the vector pPacVInteg allowing stable expression in G. lamblia under control of the promoter from the glutamate dehydrogenase (gdh) gene. The resulting transgenic strain was compared with the wild-type strain in a vitality assay, characterized with respect to susceptibility to nitazoxanide, metronidazole and—as assessed in a 96-well plate format—to a panel of 15 other compounds to be tested for anti-giardial activity.

GusA was stably expressed in G. lamblia. Using a simple glucuronidase assay protocol, drug efficacy tests yielded results similar to those from cell counting.

G. lamblia WB C6 GusA is a suitable tool for high-throughput anti-giardial drug screening.

We performed a systematic review and meta-analysis by means of an electronic search of the published literature, with no language restrictions, until October 2008. We included studies on chronically infected patients of any age who were in the indeterminate phase or had visceral involvement and for whom treatment with benznidazole was compared with placebo or no treatment. The primary endpoint was response to therapy (whether serological, parasitological or clinical), as it was measured in each of the studies included. Clinical response to therapy was also analysed.

We identified 696 studies, from which we chose 9: 3 clinical trials and 6 observational studies. Compared with placebo or no treatment, benznidazole increases 18-fold the probability of a response to therapy [global odds ratio (OR), 18.8; 95% confidence interval (CI), 5.2–68.3]. This effect was mainly observed in clinical trials (OR, 70.8; 95% CI, 16–314), whereas in observational studies it was much less marked (OR, 7.8; 95% CI, 2.1–28.9), and even less so when only observational studies in adults were considered (OR, 6.3; 95% CI, 1.6–24.7). Patients treated with benznidazole had a significantly lower risk of clinical events (OR, 0.29; 95% CI, 0.16–0.53). Up to 18% of patients discontinued treatment due to toxicity (cutaneous reactions followed by gastrointestinal disturbances); this was less common in children than in adults.

Analysis of available information reveals that the efficacy of treatment in late chronic infection is doubtful. Although data generally point to a beneficial effect, this could be marginal. This uncertainty is largely the result of differences in the study populations, endpoints and follow-up periods, and the fact that almost all of the information on treatment in the late chronic phase comes from non-randomized studies.

BALB/c mice were challenged with alginate-embedded mucoid clinical isolates isolated in 1988, 1997 or 2003. Mice were euthanized on day 1, 2 or 3 post-infection for estimation of quantitative bacteriology, histopathology, and measurement of granulocyte colony-stimulating factor (G-CSF) and macrophage inflammatory protein 2 (MIP-2).

There was a significant reduction of bacteria when comparing treatment initiated 1 h post-infection with treatment initiated after 24 h for isolates 1997 and 2003. Treatment initiated 1 h post-infection also resulted in a reduction of the pulmonary cytokines G-CSF, for all three isolates, and MIP-2, for isolates 1997 and 2003. Histological evaluation showed a shift from the acute-type inflammatory immune response to a chronic-type in mice infected with isolate 2003.

A significant reduction in the number of bacteria was observed when initiating treatment 1 h post-infection compared with initiating treatment after 24 h, although the latest isolate avoided complete clearance. Early antibiotic treatment directed at the mucoid phenotype in mice also reduced the inflammation and, thereby, the lung tissue damage.

Children were recruited in weight-based dosage bands and nutritional status classified according to weight for height. Total and unbound plasma nevirapine concentrations were measured over a full dosing interval. Multivariate linear and logistic regression analyses were performed to determine the effects of malnutrition, age, dose and other factors on nevirapine exposure and likelihood of achieving therapeutic nevirapine trough concentrations.

Forty-three children were recruited (37 included for analysis). Mild to moderate malnutrition was present in 12 (32%) children; 25 (68%) were of normal nutritional status. There was no effect of malnutrition on any measure of total drug exposure or on the unbound fraction of nevirapine. Nevirapine exposure was strongly related to dose administered (P = 0.039) and to age (for every yearly increase in age there was an ~88% increase in the odds of achieving a therapeutic nevirapine concentration; P = 0.056, 95% confidence interval 0.983–3.585).

Use of divided adult Triomune^®30 tablets in treating young children results in significant underdosing. No independent effect of malnutrition on total and unbound nevirapine exposures was observed. These data support the use of bespoke paediatric antiretroviral formulations.

Plasma and DNA samples were obtained from 330 HIV-infected Thai women who received intra-partum single-dose nevirapine in the PHPT-2 clinical trial to prevent perinatal HIV transmission. Nine SNPs within CYP2B6, CYP3A4 and ABCB1 were genotyped by real-time PCR. Nevirapine plasma concentrations were determined by HPLC and used in a population pharmacokinetic analysis.

Higher nevirapine exposure was observed in women carrying the CYP2B6 516G>T polymorphism, but this did not reach statistical significance (P = 0.054). The TGATC CYP2B6 haplotype (g.3003T, 516G, 785A, g.18492T and g.21563C) was associated with increased nevirapine clearance and lower exposure (P = 0.0029). The median time for nevirapine concentrations to reach 10 ng/mL post-partum (nevirapine IC₅₀ for HIV-1) was 14 days [interquartile range (IQR, 14–18)] for TGATC homozygotes, 16 days (14–20) for TGATC heterozygotes and 18 days (14–20) for non-TGATC homozygotes (P = 0.020).

The CYP2B6 516G>T impact on nevirapine concentrations was less pronounced after intra-partum single-dose nevirapine than reported under steady-state conditions, perhaps due to lack of enzyme auto-induction at the time of dosing. Although the TGATC CYP2B6 haplotype may shorten the persistence of nevirapine post-partum, its practical implications for the prevention of HIV transmission or selection of resistance mutations are likely limited.

A lytic bacteriophage in combination with ciprofloxacin was used for the treatment of K. pneumoniae B5055 biofilm. The efficacy and the frequency of resistant variant formation were estimated after respective treatments. The resistant variants were characterized for their virulence potential.

Bacteriophage alone was able to eradicate the biofilm effectively and no significant difference was observed in its ability to eradicate biofilm in combination with ciprofloxacin. However, combination treatment using ciprofloxacin and bacteriophage significantly arrested the emergence of resistant variants. The small number of variants that developed had a lower propensity to form biofilms, produced small amounts of cell-associated capsular polysaccharide and demonstrated increased susceptibility to mouse peritoneal macrophages. Altered morphology and changed pattern of the outer membrane proteins of bacterial isolates were also observed.

The combination treatment not only killed the bacteria, but also restricted the formation of resistant variants significantly as compared with individual treatments. Hence, a combination of bacteriophage and ciprofloxacin offers an effective strategy to combat the emergence of treatment-associated resistance.

MICs of 30 antimicrobial agents were determined by broth microdilution. Resistance and virulence genes were detected via a diagnostic DNA microarray and specific PCRs. The genomic relationships were determined by ApaI-PFGE, spa typing and SCCmec typing.

Twenty-two distinct resistance patterns were observed. All 54 isolates were tetracycline resistant, mediated by tet(M), tet(K) and/or tet(L), with 14 isolates being only resistant to β-lactam antibiotics and tetracyclines. Trimethoprim resistance, seen in 28 isolates, was mostly due to the gene dfrK or dfrG. Among the 24 macrolide/lincosamide-resistant isolates, the genes erm(A), erm(B) and/or erm(C) were detected. The two chloramphenicol/florfenicol-resistant isolates harboured the gene fexA. The eight gentamicin-resistant isolates carried the gene aacA/aphD. Fifty-three isolates harboured SCCmec type V elements while the remaining one carried mecA and ugpQ, but no recombinase genes. All isolates were PVL negative, but one and three isolates, respectively, were positive for the enterotoxin B and enterotoxin K and Q genes. Eight different spa types were identified with t011 being the most predominant. Six ApaI-PFGE clusters with up to nine individual patterns were detected.

MRSA ST398 isolates varied slightly in their virulence properties and spa types but differed distinctly in their antimicrobial resistance pheno- and genotypes as well as their ApaI-PFGE patterns. These data underline the ability of ST398 to acquire genetic material that might increase antimicrobial resistance and virulence.

Patients successfully treated with 1000 mg saquinavir boosted with 100 mg ritonavir twice daily together with two nucleoside or nucleotide reverse transcriptase inhibitors [N(t)RTIs] who were switched to 2000 mg saquinavir with 100 mg ritonavir once daily with unchanged N(t)RTI therapy were analysed. CD4 cells, HIV-RNA PCR and metabolic parameters were compared between baseline and 3, 6, 9 and 12 months after the switch. Saquinavir and ritonavir drug levels were measured before and a median of 3 weeks after switching from twice to once daily at 0, 1, 2, 4, 6, 9, 12 and 24 h after intake of the medication. The area under the serum concentration–time curve from 0 to 24 h (AUC_0–24) was calculated using the trapezoidal rule.

Eighteen patients (16 males, median age of 41 years) with a median CD4 cell count of 464 cells/mm³ were analysed. HIV-RNA PCR remained <500 copies/mL for all patients. After switching from 100 mg twice daily to 100 mg once daily, the AUC_0–24 for ritonavir decreased significantly [21 874 to 10 267 ng·h/mL, geometric mean ratio (GMR) = 0.47; P < 0.001], whereas the AUC_0–24 for saquinavir decreased only marginally from 35 000 to 34 490 ng·h/mL (GMR = 0.99; P = 0.426). The CD4 cell count and the fasting metabolic parameters remained unchanged.

Once-daily treatment with ritonavir-boosted saquinavir was well tolerated and resulted in similar saquinavir drug exposure despite much lower ritonavir concentrations when compared with a twice-daily dosing schedule.

Five Salmonella field isolates and mutants, in which efflux pump inhibitor tests previously pointed towards an up-regulation of efflux, plus one negative control were included in the study. MIC values were determined of antibiotics that were indicative of AcrAB overexpression. The regulatory regions acrRA, soxRS, marORAB, acrSE and ramRA of original strains and mutants were sequenced and compared. The gene expression of acrA, tolC, ramA and soxS was assessed by quantitative real-time PCR. Conjugation experiments and tet gene PCRs were performed to explain unexpected variations in MIC values of tetracycline.

In four mutant strains, changes in the ramRA regulatory region, causing up-regulation of ramA, were detected. These changes comprised point mutations and deletions of 10 or 15 bp within the ramR gene and a single bp exchange located in the binding site of the RamR protein in Salmonella Infantis, Paratyphi and Livingstone mutants. An insertion of 49 bp within the soxR gene was involved in soxS up-regulation and enhanced efflux activity in the fifth mutant from Salmonella Virchow. The loss of tetracycline resistance in one Salmonella Paratyphi mutant could be explained by the loss of a plasmid carrying a tet(A) gene.

Changes in the ramR-ramA region as well as in the soxR gene occur in mutants of Salmonella serovars other than Typhimurium and seem to be involved in the up-regulation of efflux activity.

A retrospective analysis of microbiology data from two centres in Maryland and Chicago was performed. Adult hospital inpatients with positive clinical cultures for specific antimicrobial-resistant bacterial pathogens between 1999 and 2005 (55 427 isolates) were included. The proportions of isolates not susceptible to specific antimicrobial agents were compared between patients ≥65 and <65 years. Additional analyses examined temporal trends in the frequency of resistance and the frequency of resistance among the oldest patients (≥80 years), in bacteria isolated from blood cultures and in bacteria obtained from intensive care unit patients.

Heterogeneity was observed in the frequency of resistance among different bacteria between older and younger patients, between the two centres and over the study period. Staphylococcus aureus isolates were more likely to be resistant to methicillin when obtained from older patients at Chicago (50.9% versus 40.9%; P < 0.001). In contrast, younger patients yielded a greater proportion of enterococci resistant to vancomycin at Maryland (19.4% versus 16.5%; P = 0.009). Results were variable when resistance to fluoroquinolones, cephalosporins and imipenem were compared for Pseudomonas aeruginosa, Escherichia coli and Klebsiella spp.

Overall, advanced patient age was not uniformly associated with a greater likelihood of antimicrobial resistance among all bacterial pathogens. Moreover, the frequency of resistance in older and younger patients varied considerably at the two sites over the study period. Variability in the frequency of resistance precludes simplistic conclusions regarding the relationship between age and resistance.

A random stratified, cross-sectional prevalence survey was conducted in NH residents who were screened for MRSA carriage by multisite enriched culture. Characteristics of NHs and residents were collected by a questionnaire survey and analysed by two-stage logistic regression modelling. MRSA isolates were genotyped by PFGE, staphylococcal cassette chromosome mec (SCCmec) typing, multilocus sequence typing (MLST) and resistance genes.

Of 2953 residents screened in 60 NHs, 587 (19.9%) were MRSA carriers. Risk factors included hospital contact, antibiotic exposure, impaired mobility and skin lesions at the resident level, and lack of MRSA surveillance, lack of antibiotic therapeutic formulary and the combination of less-developed infection control activities and a high ratio of physicians to residents at the institution level. MRSA isolates showed eight major types, three of which were predominant: B2-ST45-SCCmec IV (49%; where ST stands for sequence type); A21-ST8-SCCmec IV (13%); and A20-ST8-SCCmec IV (10%). Each was recovered in 55, 21 and 25 NHs, respectively. The geographical distribution of NH genotypes paralleled that of acute-care hospitals.

A high prevalence of MRSA carriage in NH residents was associated with hospital care, co-morbidities and less-developed coordination of institutional care. The predominant MRSA strains from NH residents and hospitalized patients of the same area were identical. Strengthening and coordination of MRSA surveillance and control activities are warranted within and between NHs and hospitals.

A total of 308 CNSPA isolates collected at a medical centre from 2000 to 2005 and 26 XDRPA collected from six medical centres in different regions of Taiwan in 2003 were included. MBL genes and Tn6001 were detected by PCR. Clonal relatedness was determined by PFGE.

Of the 308 CNSPA isolates, 30 (10%) were XDRPA, including 27 (9%) colistin-only-susceptible (COS) and 3 (1%) colistin-only-intermediate (COI) P. aeruginosa. bla_VIM-3 was found in 16 (53%) isolates of the XDRPA (n = 30), whereas only 72 (26%) of the non-XDRPA (n = 278) carried the gene. In450 was higher in COS P. aeruginosa (12/27; 44%) than in non-XDRPA isolates (53/278; 19%). Tn6001 was highest in COS P. aeruginosa (11/27; 41%), followed by COI P. aeruginosa (1/3; 33%), and lowest in non-XDRPA (46/278; 17%). Of 26 XDRPA from six medical centres, higher prevalences of bla_VIM-3 (16/26; 62%), In450 (16/26; 62%) and Tn6001 (12/26; 46%) were found. Genotyping by PFGE revealed 60 pulsotypes. Hybridization of a bla_VIM-3-specific probe following PFGE suggested that the mobile element Tn6001 might have transferred horizontally.

Tn6001 and In450 play an important role in the dissemination of CNSPA and XDRPA. The prevalence of these genetic constituents was higher in XDRPA than in non-XDRPA isolates, suggesting that the mobile element Tn6001 might have transferred horizontally.

Data on clinical activity and outcomes were collected prospectively on 334 episodes of treatment administered by the Sheffield OPAT service between January 2006 and January 2008. Cost-effectiveness was calculated by comparing real costs of OPAT with estimated inpatient costs for these patient episodes incorporating two additional sensitivity analyses.

Of the OPAT episodes, 87% resulted in cure or improvement on completion of intravenous therapy. The readmission rate was 6.3%, and patient satisfaction was high. OPAT cost 41% of equivalent inpatient costs for an Infectious Diseases Unit, 47% of equivalent inpatient costs using national average costs and 61% of inpatient costs using minimum inpatient costs for each diagnosis.

Using this service model, OPAT is safe and clinically effective, with low rates of complications/readmissions and high levels of patient satisfaction. OPAT is cost-effective when compared with equivalent inpatient care in the UK healthcare setting.