TY - JOUR
T1 - Molecular Mechanisms Associated with Nosocomial Carbapenem-resistant Acinetobacter baumannii in Mexico
AU - Alcántar-Curiel, María Dolores
AU - García-Torres, Luis Francisco
AU - González-Chávez, María Inés
AU - Morfín-Otero, Rayo
AU - Gayosso-Vázquez, Catalina
AU - Jarillo-Quijada, Ma Dolores
AU - Fernández-Vázquez, José Luis
AU - Giono-Cerezo, Silvia
AU - Rodríguez-Noriega, Eduardo
AU - Santos-Preciado, José Ignacio
N1 - Publisher Copyright:
© 2014 IMSS.
PY - 2014/10/1
Y1 - 2014/10/1
N2 - Background and Aims: Acinetobacter baumannii is an emerging pathogen worldwide that is most commonly associated with nosocomial infections and multi-drug resistance. In the present study we determined the mechanisms of carbapenem resistance and clonal diversity of A. baumannii nosocomial isolates in Hospital Civil de Guadalajara, Mexico. Methods: A total of 303 clinical isolates of A. baumannii identified during a period expanding from 2004-2011 were analyzed for carbapenem resistance using several microbiological and molecular methods. Clonal relatedness of these isolates was determined using pulsed-field gel electrophoresis. Results: Of the 303 isolates, 84% were resistant to meropenem, 71.3% to imipenem and 78.3% the resistant isolates were positive for metallo-β-lactamases as determined by the phenotypic assay. In addition, 49.6% of carbapenem-intermediate or -resistant isolates carried the blaOXA-72 gene and 1.2% carried the blaVIM-1 gene. Efflux pump phenotype was responsible for reduced susceptibility to meropenem in 14.5% and to imipenem in 31.6% of the resistant isolates, respectively in the presence of the efflux pump inhibitor, carbonyl cyanide 3-chlorophenylhydrazone. Strains representing different carbapenem-resistant patterns exhibited reduced expression of 22, 29, 33, and 43kDa OMPs. Among the bacterial collection studied, 48 different clones were identified, two of which were predominant and persistently transmitted. Conclusions: Carbapenemase production in combination with efflux pump expression, reduction in OMPs expression and the cross-transmission of clones appear to be major contributors to the high frequency of carbapenem-resistance observed in A. baumannii. To our knowledge, this is the first study to define the molecular mechanisms associated with carbapenem-resistance in A. baumannii in Mexico.
AB - Background and Aims: Acinetobacter baumannii is an emerging pathogen worldwide that is most commonly associated with nosocomial infections and multi-drug resistance. In the present study we determined the mechanisms of carbapenem resistance and clonal diversity of A. baumannii nosocomial isolates in Hospital Civil de Guadalajara, Mexico. Methods: A total of 303 clinical isolates of A. baumannii identified during a period expanding from 2004-2011 were analyzed for carbapenem resistance using several microbiological and molecular methods. Clonal relatedness of these isolates was determined using pulsed-field gel electrophoresis. Results: Of the 303 isolates, 84% were resistant to meropenem, 71.3% to imipenem and 78.3% the resistant isolates were positive for metallo-β-lactamases as determined by the phenotypic assay. In addition, 49.6% of carbapenem-intermediate or -resistant isolates carried the blaOXA-72 gene and 1.2% carried the blaVIM-1 gene. Efflux pump phenotype was responsible for reduced susceptibility to meropenem in 14.5% and to imipenem in 31.6% of the resistant isolates, respectively in the presence of the efflux pump inhibitor, carbonyl cyanide 3-chlorophenylhydrazone. Strains representing different carbapenem-resistant patterns exhibited reduced expression of 22, 29, 33, and 43kDa OMPs. Among the bacterial collection studied, 48 different clones were identified, two of which were predominant and persistently transmitted. Conclusions: Carbapenemase production in combination with efflux pump expression, reduction in OMPs expression and the cross-transmission of clones appear to be major contributors to the high frequency of carbapenem-resistance observed in A. baumannii. To our knowledge, this is the first study to define the molecular mechanisms associated with carbapenem-resistance in A. baumannii in Mexico.
KW - Acinetobacter baumannii
KW - Carbapenem
KW - Nosocomial infections
KW - OXA-72
KW - Resistance
UR - http://www.scopus.com/inward/record.url?scp=84915782199&partnerID=8YFLogxK
U2 - 10.1016/j.arcmed.2014.10.006
DO - 10.1016/j.arcmed.2014.10.006
M3 - Artículo
SN - 0188-4409
VL - 45
SP - 553
EP - 560
JO - Archives of Medical Research
JF - Archives of Medical Research
IS - 7
ER -