Prevalence of class A carbapenemase (KPC)-producing enterobacteriaceae and Pseudomonas isolates from two tertiary hospitals in Metro Manila

Carbapenems, i.e. imipenem, meropenem, and ertapenem, are Ý-lactams used in the treatment of serious infections caused by multiple drug resistant bacteria. However, outbreaks of Class A Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria have been reported in hospitals all over the world. KPC is an enzyme that is capable of carbapenem hydrolysis, rendering it ineffective. The gene that encodes this enzyme is found in conjugative plasmids making it more transmissible to other bacteria. This study determined the occurrence of KPCproducing Enterobacteriaceae, namely: Klebsiella spp., Enterobacter spp. and Escherichia coli, collected over a 3-month period from patients of the Ospital ng Makati, Makati City, and KPC-producing Pseudomonas spp. collected over a one month period from cases of the Philippine General Hospital. Carbapenem susceptibility of the isolates was determined using the disk diffusion method, while modified Hodge test (MHT) was used to detect carbapenemase production. Isolates were suspected of KPC production if they were resistant to at least one carbapenem and had a positive Modified Hodge Test result. Of the 140 Enterobacteriaceae isolates included in the study, six (6 or 4.3%) were found to be resistant to carbapenems using the disk diffusion method while three (3 or 2.14%) were positive for carbapenemase production using the MHT. Among the 47 Pseudomonas isolates, nineteen (19 or 40.42%) were resistant to a carbapenem; but all were negative in modified Hodge test. The presence of the blaKPC gene coding for the carbapenem resistance was determined using the polymerase chain reaction. Analysis of the PCR product using gel electrophoresis, showed that the blaKPC gene was absent in the isolates that were suspected of carbapenemase production