Laboratory studies on Yersinia pestis during the 1991 outbreak of plague in Lushoto, Tanzania.

Thirty-one specimens from patients involved in an outbreak of plague were cultured. Suspicious isolates were presumptively identified by colonial characteristics, simple strains and by API 20E, and confirmed by inoculation into white mice. Antimicrobial susceptibility testing was also done. The isolation rate of Y. pestis was 22.6%. All isolates were uniformly sensitive to tetracycline, streptomycin, sulphadimidine and chloramphenicol; moderately sensitive to erythromycin, and resistant to trimethoprim. Y. pestis was confirmed as a cause of the epidemic and sensitivity of Y. pestis to the four antimicrobial agents used was demonstrated. It is recommended that laboratories in zonal hospitals serving areas with plague foci should be provided with facilities for isolation and preliminary identification of Y. pestis in order to speed up diagnosis of plague outbreaks. Confirmation of the identity, biotyping and antibiotic susceptibility testing should be undertaken in a well established national reference laboratory. This appears to be the first publication on bacteriological investigations of human plague in Tanzania.