RESUMO
Correct identification of nonfermenting Gram-negative bacilli (NFB) is crucial for patient management. We compared phenotypic identifications of 96 clinical NFB isolates with identifications obtained by 5' 16S rRNA gene sequencing. Sequencing identified 88 isolates (91.7%) with >99% similarity to a sequence from the assigned species; 61.5% of sequencing results were concordant with phenotypic results, indicating the usability of sequencing to identify NFB.
Assuntos
Técnicas Bacteriológicas/métodos , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/diagnóstico , Técnicas de Tipagem Bacteriana , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Sensibilidade e Especificidade , Análise de Sequência de DNARESUMO
Although accurate in the identification of Mycobacterium species, partial 16S rRNA gene sequencing does not distinguish Mycobacterium chelonae from M. abscessus. Thus, we designed a SmartCycler PCR assay targeting the 16S-to-23S internal transcribed spacer (ITS) region with use of MGB Eclipse probes to distinguish each species. Comparison with PCR-restriction enzyme analysis of a 441-bp fragment of the hsp65 gene resulted in 100% correlation with 25 isolates of M. chelonae and 25 isolates of M. abscessus. ITS PCR performed on 90 consecutive isolates identified by partial 16S rRNA gene sequencing (26 isolates of the M. chelonae-M. abscessus complex and 64 remaining isolates, including Mycobacterium species, Nocardia species, and other aerobic actinomycetes) showed 100% specificity and sensitivity. The ITS PCR assay is accurate and specific, easy to perform, and a good supplemental test when using partial 16S rRNA gene sequencing to identify M. chelonae and M. abscessus.