ABSTRACT
Yersinia pestis is the causative agent of plague, a fulminant disease that is often fatal without antimicrobial treatment. Plasmid (IncA/C)-mediated multidrug resistance in Y. pestis was reported in 1995 in Madagascar and has generated considerable public health concern, most recently because of the identification of IncA/C multidrug-resistant plasmids in other zoonotic pathogens. Here, we demonstrate no resistance in 392 Y. pestis isolates from 17 countries to eight antimicrobials used for treatment or prophylaxis of plague.
Subject(s)
Anti-Bacterial Agents/therapeutic use , Plague/drug therapy , Yersinia pestis/genetics , Africa , Americas , Animals , Asia , Drug Resistance, Bacterial , Humans , Madagascar , Microbial Sensitivity Tests , Phylogeography , Plague/microbiology , Plague/transmission , Plasmids/genetics , Public Health , Siphonaptera , Yersinia pestis/isolation & purificationABSTRACT
The utility of Etest for antimicrobial susceptibility testing of Yersinia pestis was evaluated in comparison with broth microdilution and disk diffusion for eight agents. Four laboratories tested 26 diverse strains and found Etest to be reliable for testing antimicrobial agents used to treat Y. pestis, except for chloramphenicol and trimethoprim-sulfamethoxazole. Disk diffusion testing is not recommended.
Subject(s)
Anti-Bacterial Agents/pharmacology , Yersinia pestis/drug effects , Humans , Microbial Sensitivity Tests/methodsABSTRACT
Due to concern that Francisella tularensis, the causative agent of tularemia, may be used as a bioterrorist weapon, the Clinical and Laboratory Standards Institute recently provided a susceptibility testing method with breakpoints. Here, 169 isolates (92 type A and 77 type B) from North America were tested against seven antimicrobial agents (streptomycin, gentamicin, tetracycline, doxycycline, ciprofloxacin, levofloxacin, and chloramphenicol) used for the treatment of tularemia. The MICs for all of the isolates fell within the susceptible range. In addition, all isolates had MICs for erythromycin of 0.5 to 4 microg/ml, in contrast to an MIC of >256 microg/ml for the common laboratory strain LVS (live vaccine strain).
Subject(s)
Anti-Bacterial Agents/pharmacology , Francisella tularensis/drug effects , Tularemia/microbiology , Anti-Bacterial Agents/therapeutic use , Francisella tularensis/classification , Francisella tularensis/isolation & purification , Humans , Microbial Sensitivity Tests/standards , North America , Tularemia/drug therapyABSTRACT
Francisella tularensis is a potent pathogen and a possible bioterrorism agent, for which quinolones offer promising new therapeutic options. There are, however, no data on the susceptibility to quinolones of natural isolates of F. tularensis tularensis, the highly virulent North American subspecies. In the present study, 8 isolates of F. tularensis tularensis, originating from 8 different states of the USA, and 16 US isolates of F. tularensis holarctica were tested. All 24 isolates showed MIC values < or = 0.125 mg/l to 6 different quinolones. Against ciprofloxacin, the predominant quinolone used to date in therapy against subspecies holarctica, MIC values were consistently < or = 0.064 mg/l. Thus quinolones seem to be promising options for the treatment of tularemia, including cases caused by the highly virulent subspecies F. tularensis tularensis.