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Resistance Markers and Genetic Diversity in Acinetobacter baumannii Strains Recovered from Nosocomial Bloodstream Infections
Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil
Departamento de Parasitologia e Biologia, Universidade CEUMA, José Montello 1, 31067-120, São Luis do Maranhão, Brazil
Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Professor Alfredo Balena 190, Santa Efigênia 30130-100, Belo Horizonte, MG, Brazil
* Author to whom correspondence should be addressed.
Received: 28 October 2013; in revised form: 9 January 2014 / Accepted: 18 January 2014 / Published: 28 January 2014
Abstract: In this study, phenotypic and genotypic methods were used to detect metallo-β-lactamases, cephalosporinases and oxacillinases and to assess genetic diversity among 64 multiresistant Acinetobacter baumannii strains recovered from blood cultures in five different hospitals in Brazil from December 2008 to June 2009. High rates of resistance to imipenem (93.75%) and polymyxin B (39.06%) were observed using the disk diffusion (DD) method and by determining the minimum inhibitory concentration (MIC). Using the disk approximation method, thirty-nine strains (60.9%) were phenotypically positive for class D enzymes, and 51 strains (79.6%) were positive for cephalosporinase (AmpC). Using the E-test, 60 strains (93.75%) were positive for metallo-β-lactamases (MβLs). All strains were positive for at least one of the 10 studied genes; 59 (92.1%) contained blaVIM-1, 79.6% contained blaAmpC, 93.7% contained blaOXA23 and 84.3% contained blaOXA51. Enterobacteria Repetitive Intergenic Consensus (ERIC)-PCR analysis revealed a predominance of certain clones that differed from each other. However, the same band pattern was observed in samples from the different hospitals studied, demonstrating correlation between the genotypic and phenotypic results. Thus, ERIC-PCR is an appropriate method for rapidly clustering genetically related isolates. These results suggest that defined clonal clusters are circulating within the studied hospitals. These results also show that the prevalence of MDR A. baumannii may vary among clones disseminated in specific hospitals, and they emphasize the importance of adhering to appropriate infection control measures.
Keywords: Acinetobacter baumannii; bloodstream infections; genetic diversity; resistance markers
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Martins, H.S.I.; Bomfim, M.R.Q.; França, R.O.; Farias, L.M.; Carvalho, M.A.R.; Serufo, J.C.; Santos, S.G. Resistance Markers and Genetic Diversity in Acinetobacter baumannii Strains Recovered from Nosocomial Bloodstream Infections. Int. J. Environ. Res. Public Health 2014, 11, 1465-1478.
Martins HSI, Bomfim MRQ, França RO, Farias LM, Carvalho MAR, Serufo JC, Santos SG. Resistance Markers and Genetic Diversity in Acinetobacter baumannii Strains Recovered from Nosocomial Bloodstream Infections. International Journal of Environmental Research and Public Health. 2014; 11(2):1465-1478.
Martins, Hanoch S.I.; Bomfim, Maria R.Q.; França, Rafaela O.; Farias, Luiz M.; Carvalho, Maria A.R.; Serufo, José C.; Santos, Simone G. 2014. "Resistance Markers and Genetic Diversity in Acinetobacter baumannii Strains Recovered from Nosocomial Bloodstream Infections." Int. J. Environ. Res. Public Health 11, no. 2: 1465-1478.