Detection of serinocarbapenemases Class A and other mechanisms of enzymatic resistance to beta-lactams in enterobacteria strains with diminished susceptibility to carbapenems isolated of patients in a university hospital

作者：de la Lastra Virginia; Rivas Lina M; Silva Francisco; Teresa Ulloa M; Eugenia Pinto M; Vidal Mario

来源：Revista Chilena de Infectologia, 2014, 31(6): 682-688.

DOI：10.4067/S0716-10182014000600007

• Carbapenemases
• carbapenems
• beta-lactamic resistance
• enterobacteria
• active surveillance

Background: The emergence of carbapenemase mediated resistance in Enterobacteriaceae has a strong clinical impact. This study aimed to do a genotypic and phenotypic characterization of the enzymatic resistance to beta-lactams in clinical Enterobacteriaceae isolates with decreased susceptibility to carbapenems in a university medical center in Santiago. Methods: During April-September 2010 at Hospital Clinic Universidad de Chile, 23 isolates of carbapenem non susceptible Enterobacteriaceae were collected. We used PCR for the detection of class A carbapenemases (SME, IMI, NMC, GES and KPC) and the modified Hodge with the boronic acid test to phenotypically assess the presence of serine-carbapenemases. To assess extended spectrum beta-lactamases (ESBLs) the CLSI phenotypic teas were performed. Metallo-beta-lactamases (MBL) and AmpC were assessed with commercial tablets. Results: 18/23 were Klebsiella pneumoniae and 5/23 strains were Enterobacter cloacae. All PCR to class A carbapenemases were negative. 3/23 strains (all E. cloacae), were positive to the Hodge modified test and 1/23, a K.pneumoniae, was positive to the boronic acid test. ESBLs were detected in 14/23 Os the strains and AmpC in 5/23. No MBL was detected. Conclusion: No class A serine-carbapenemasa was detected. The decreased susceptibility to carbapenems is probably explained by the P-lactamase activity and due to porin loss.

• 出版日期2014-12