RESUMO
Se utilizaron 62 cepas identificadas inicialmente como bacilos gramnegativos no fermentadores (BGNNF), aisladas de pacientes con diagnóstico de infección nosocomial, con el objeto de determinar su género y especie. Cuarenta y cinco cepas fueron identificadas como Acinetobacter baumannii, 10 como Pseudomonas aeruginosa, 3 como Stenotrophomonas maltophilia, 3 como Comamonas acidovorans y 1 como Achromobacter xylosoxidans subsp. xylosoxidans, mediante el API 20NE. Con respecto a las cepas de Acinetobacter, el ARDRA permitió identificar 20 cepas como A. baumannii y 23 como Acinetobacter genoespecie 13TU, pero 2 cepas no fueron identificadas por este método. La secuencia de la subunidad 16S del ADNr de todas las cepas incluidas en este estudio permitió identificar 20 cepas como A. baumannii, 23 cepas como Acinetobacter RUH1139, 10 como P. aeruginosa, 4 como A. xylosoxidans subsp. xylosoxidans (2 de estas cuatro cepas habían sido identificadas como A. baumannii mediante API20NE), 3 como S. maltophilia, 1 como C. acidovorans y 1 como β-Proteubacterium. Las discrepancias entre la identificación bioquímica por API 20NE y por ARDRA, para diferenciar las genoespecies de Acinetobacter, fue resuelta por la secuenciación de la subunidad 16S del ADNr, indicando que la identificación de los aislados de Acinetobacter, entre otros BGNNF, mediante API 20NE, debe ser confirmada por técnicas genéticas.
We used 62 strains initially identified as non fermenting gram-negative bacilli (NFGNB) isolated from patients with a nosocomial infection diagnosis with the purpose of identifying their genus and species. Forty five strains were identified as Acinetobacter baumannii, 10 as Pseudomonas aeruginosa, 3 as Stenotrophomonas maltophilia, 3 as Comamonas acidovorans and 1 as Achromobacter xylosoxidans subspecies xylosoxidans through the API 20NE. Regarding the Acinetobacter strains, the ARDRA allowed to identify 20 strains as A. baumannii and 23 as Acinetobacter genospecies 13TU, but 2 strains were not identified with this method. The ADNr 16S sequence of all the strains included in this study allowed to identify 20 strains as A. baumannii, 23 strains as Acinetobacter RUH1139, 10 as P. aeruginosa, 4 as A. xylosoxidans subsp. xylosoxidans (2 of these four strains strains had been identified as A. baumannii through API20NE), 3 as S. maltophilia, and 1 as C. acidovorans and 1 as β-Proteubacterium. The discrepancies between the biochemical identification by API 20NE and by ARDRA to differentiate the Acinetobacter genospecies was resolved by the ADNr16S sequencing, indicating that the identification of the Acinetobacter isolates, among other NFGNB, through API 20NE, should be confirmed through genetic techniques.
RESUMO
Salmonella Infantis has been the second most common serovar in Argentina in the last two years, being isolated mostly from paediatric hospitalised patients. In order to determine the clonal relationship among Salmonella Infantis strains, we examined 15 isolates from paediatric patient faeces in Argentina (12 geographically related and 3 geographically non-related) by using antimicrobial susceptibility, plasmid profiling, repetitive extragenic palindromic (REP) PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR, and low-frequency restriction analysis of chromosomal DNA by pulsed field gel electrophoresis (PFGE). Four Spanish strains were included as controls of clonal diversity in molecular techniques. Antibiotype and plasmid profile was not useful as epidemiological tools. PFGE and REP-PCR were able to discriminate between Argentinean and Spanish isolates of Salmonella Infantis allowing to detect genetically related strains in three different cities. This finding indicates that a possible spread of a clone of this serovar in the North-eastern Region of Argentina has taken place in 1998