JAC Advance Access originally published online on March 3, 2004
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Journal of Antimicrobial Chemotherapy (2004) 53, 683-685
© 2004 The British Society for Antimicrobial Chemotherapy
Correspondence |
Comparison of the in vitro efficacy of telithromycin (HMR 3647) and levofloxacin with 22 antibiotic compounds against Bosea and Afipia species
1 Unité des Rickettsies, CNRS UPRESA 6020, Faculté de Médecine, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05; 2 Anti-Infective Research Department, Laboratoire Aventis, 93235 Romainville, France
Keywords: amoebae, pneumonia, Proteobacteria
Sir,
As a part of our research into the diversity of bacterial agents associated with amoebae in hospital water supplies, we have previously identified new 
Proteobacteria belonging mostly to Afipia and Bosea genera.1,2 It has been established that Afipia is responsible for cat scratch disease and nosocomial osteitis,3 and in addition we have demonstrated that patients with nosocomial pneumonia hospitalized near contaminated water in a public hospital in our city had elevated antibody titres to these bacteria and that seroconversion to Bosea massiliensis was significantly associated with pneumonia in the intensive care unit.4 As few data about the antibiotic susceptibility of this group of bacteria are available, we tested 24 antibiotics including the new compound telithromycin (HMR 3647).
Strains and antibiotics used in the study are presented in Table 1. Antibiotics were provided by the different antibiotic manufacturers. Strains were grown for 72–96 h on BCYE agar before testing. Antibiotic susceptibility testing was carried out using a micro broth dilution method in nutrient broth. For the testing of co-trimoxazole, 5% lysed horse blood was added. The final inoculum for all broth tests ranged from 1 x 105 to 5 x 105 cfu/mL. The plates were incubated at 30°C and read between 72 and 96 h. As there is no standard method to test antibiotic susceptibility of these fastidious bacteria, Escherichia coli (ATCC 25922) and Enterococcus faecalis (ATCC 29212) tested under the same conditions, were used as controls.
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MICs results are summarized in Table 1. The results of MICs observed for controls are in accordance with those obtained using the NCCLS guidelines. In this study, most of the strains had high MICs to all antibiotics tested and none of the antibiotics tested was efficient against all strains. This work confirms that Afipia felis is a bacterium resistant to almost all antibiotics.3,5 In contrast, rifampicin, tobramycin and imipenem were more effective against the phylogenetically homogeneous group of Afipia,1 except for the three Afipia genospecies. Doxycycline, the sole antibiotic with low MICs, was effective against all Bosea species. In all cases, MICs of levofloxacin were equal to or lower than the MICs of ciprofloxacin against all the species of Afipia, except Afipia birgiae and Afipia massiliensis. However, none of the MICs observed were lower than 2 mg/L for this antibiotic. Telithromycin was effective against B. massiliensis and Afipia clevelandensis with MICs
0.25 mg/L but the MICs were high for other species. Most antibiotic regimens currently proposed for patients with hospital-acquired pneumonia would be ineffective owing to these agents having high MICs against most Bosea and Afipia species.6 The use of imipenem, alone or in combination with an aminoglycoside such as tobramycin would be the most appropriate regimen, except for Bosea species that should be treated with doxycycline or telithromycin in the case of B. massiliensis-related infection. Further studies are needed to evaluate the true prevalence of these bacteria in cases of hospital-acquired pneumonia as their response to current antibiotic protocols is likely to be poor.
Acknowledgements
The authors are indebted to Lina Barrassi for technical help. This work was supported by a grant from Laboratoire Aventis.
Footnotes
* Corresponding author. Tel: +33-4-91-38-55-17; Fax: +33-4-91-83-03-90; E-mail: Didier.Raoult{at}medecine.univ-mrs.fr 
References
1 . La Scola, B., Mallet, M. N., Grimont, P. A. D. et al. (2002). Description of Afipia birgiae sp. nov., Afipia massiliae sp. nov. and recognition of Afipia felis genospecies A. International Journal of Systematic and Evolutionary Microbiology 52, 1773–82.[Abstract]
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La Scola, B., Mallet, M. N., Grimont, P. A. D. et al. (2003). Bosea eneae sp. nov., Bosea massiliensis sp. nov. and Bosea vestrisii sp. nov., isolated from hospital water supplies, and emendation of the genus Bosea (Das et al. 1996). International Journal of Systematic and Evolutionary Microbiology 53, 15–20.
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Brenner, D. J., Hollis, D. G., Moss, C. W. et al. (1991). Proposal of Afipia gen. nov. with Afipia felis gen. nov. sp. nov. (formerly the cat scratch bacillus), Afipia clevelandensis sp. nov. (formerly the Cleveland clinic foundation strain), Afipia broomeae sp. nov. and three unnamed genospecies. Journal of Clinical Microbiology 29, 2450–60.
4 . La Scola, B., Boyadjiev, I., Greub, G. et al. (2003). Amoebae-associated bacteria from water are associated with culture negative ventilator-associated pneumonia. Emerging Infectious Diseases 9, 815–21.[Web of Science][Medline]
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Maurin, M., Lepocher, H. & Raoult, D. (1993). Antibiotic susceptibilities of Afipia felis in axenic medium. Antimicrobial Agents and Chemotherapy 37, 1410–3.
6 . American Thoracic Society. (1995). Hospital-acquired pneumonia in adults: diagnosis, assessment of severity, initial antimicrobial therapy, and preventive strategies. American Journal of Respiratory and Critical Care Medicine 153, 1711–25.
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