Dados do Trabalho

Título

Identification of contaminants in Yersinia pestis cultures from the Fiocruz/CYP collection

Introdução

Yersinia pestis is the causative agent of plague, a rodent zoonosis that affects humans and other mammals and is endemic in many countries in Africa, Asia, the former Soviet Union and the Americas. The Yersinia pestis Collection (Fiocruz/CYP) is a significant repository of strains of this bacterium, isolated during epidemics and surveillance activities in various regions of Brazil between 1966 and 1997. However, culturing these strains presents challenges due to their pathogenic nature and slow growth, increasing the likelihood of contamination. As an initiative to revitalize and decontaminate subcultures in the Fiocruz/CYP, a modified selective medium CYP Broth, was developed. However, despite significant improvement, contaminants are occasionally still observed. 

Objetivo (s)

The objective of this study was to isolate and identify the main bacterial species contaminating the Y. pestis cultures from the Fiocruz/CYP collection. 

Material e Métodos

After identifying the presence of contaminant isolates in Y. pestis cultures during the routine reactivation of strains in CYP Broth, the contaminating microorganisms were initially reisolated on MacConkey agar plates. Genomic DNA was extracted, and the 16S rRNA gene was amplified via PCR and analyzed on agarose gel. Purified PCR products were sequenced using the Sanger method and compared to GenBank entries via BLAST. 

Resultados e Conclusão

A total of 718 Y. pestis culture tubes were evaluated. Among these, 22 (3.1%) tested positive for the presence of bacterial contaminants. The main contaminant species were environmental bacteria commonly found in soil, water, and other natural sources. The predominant species was Roseomonas mucosa, comprising 14 isolates (63.6% of contaminants), followed by Pantoea agglomerans with 5 isolates (22.8%) and Pseudomonas fluorescens with 3 isolates (13.6%). In conclusion, the identification of a variety of contaminants in the Y. pestis culture tubes underscores the importance of microbiological characterization to understand and control contamination, suggesting potential environmental sources of contamination and highlighting the need for adequate control measures.

Palavras Chave

YERSINIA PESTIS; PLAGUE; BIOLOGICAL CONTAMINATION