de Oliveira Sant'Anna Lincoln, Dos Santos Louisy Sanches, Ramos Juliana Nunes, Bokermann Sérgio, Bernardes Sousa Mireille Ângela, Prates Fernanda Diniz, Mattos-Guaraldi Ana Luíza, Vieira Verônica Viana, Araújo Max Roberto Batista
Laboratory of Diphtheria and Corynebacteria of Clinical Relevance, Department of Microbiology, Immunology and Parasitology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
Bacteriology Branch, Adolfo Lutz Institute, Secretary of Health of the State of São Paulo, São Paulo, Brazil.
Braz J Microbiol. 2024 Dec;55(4):3269-3277. doi: 10.1007/s42770-024-01526-4. Epub 2024 Oct 7.
The genus Corynebacterium is the largest genera among corynebacteria and has a range of species widely spread in ecological niches, some with epidemic potential and capable of causing fatal diseases. In recent years, due to the reclassifications and discoveries of new potentially toxin-producing species, microbiological identification and epidemiological control have been compromised, becoming possible only with sequencing techniques. Two bacterial strains isolated from a cat were identified by MALDI-TOF mass spectrometry as Corynebacterium diphtheriae and sent to the collaborating center of the Brazilian Ministry of Health for molecular identification and determination of toxigenicity potential, which were initially performed by multiplex PCR method. In addition, the antimicrobial susceptibility profile was determined according to BrCAST. Finally, for the final identification at the species level and effective epidemiological monitoring, the sequencing of the 16S rRNA and rpoB housekeeping genes was carried out. The isolates were identified as nontoxigenic C. diphtheriae strains by mPCR. Both strains were found susceptible to all antimicrobial agents. Although the identification at the species level was not possible through similarity analysis of S rRNA and rpoB housekeeping genes, the phylogenetic analysis showed that the isolates belonged to the species Corynebacterium rouxii with a high value of reliability. This is the first report of the isolation of C. rouxii in Latin America. Molecular identification, whether by the MALDI-TOF mass spectrometry or PCR techniques, does not discriminate C. rouxii from C. diphtheriae, requiring gene sequencing and phylogenetic analysis for correct identification at the species level.
棒状杆菌属是棒状杆菌中最大的属，有一系列物种广泛分布于生态位中，其中一些具有流行潜力并能导致致命疾病。近年来，由于新的潜在产毒物种的重新分类和发现，微生物鉴定和流行病学控制受到影响，只有通过测序技术才有可能实现。通过基质辅助激光解吸电离飞行时间质谱法将从一只猫身上分离出的两株细菌鉴定为白喉棒状杆菌，并送往巴西卫生部合作中心进行分子鉴定和产毒潜力测定，最初采用多重聚合酶链反应方法。此外，根据巴西抗菌药物敏感性试验（BrCAST）确定抗菌药物敏感性谱。最后，为了在物种水平上进行最终鉴定和有效的流行病学监测，对16S rRNA和rpoB管家基因进行测序。通过多重聚合酶链反应（mPCR）将分离株鉴定为无毒白喉棒状杆菌菌株。发现这两株菌株对所有抗菌药物均敏感。尽管通过16S rRNA和rpoB管家基因的相似性分析无法在物种水平上进行鉴定，但系统发育分析表明，分离株属于鲁氏棒状杆菌，可靠性较高。这是拉丁美洲首次报道分离出鲁氏棒状杆菌。无论是通过基质辅助激光解吸电离飞行时间质谱法还是聚合酶链反应技术进行分子鉴定，都无法区分鲁氏棒状杆菌和白喉棒状杆菌在物种水平上的正确鉴定，需要进行基因测序和系统发育分析。
