ABSTRACT
Background: Increasing Carbapenem resistance in Pseudomonas aeruginosa is an emerging threat and a matter of particular concern. Aim: Our study was conducted to find out the prevalence of Metallo beta lactamase producing Pseudomonas aeruginosa and compare various phenotypic MBL detection methods. Methods: A prospective study was conducted on 86 non duplicate Pseudomonas aeruginosa strains isolated from clinical specimens for a period of 2 year from April 2011 to march 2013. Total 86 isolates of Pseudomonas aeruginosa were included in the study. All clinical samples were processed according to standard microbiological method. The MIC for Imipenem and Meropenem were determined by broth dilution method. As per CLSI any isolate having an MIC of >8μg/ml was considered resistant.42 isolates were both or either resistant to IMP and MRP. These 42 isolates were tested for MBL production by (a) IMP EDTA E test (17 MBL positive isolate detected), (b) IMP & IMP EDTA disc diffusion test (17 MBL positive isolate detected), (c) IMP & EDTA double disc synergy test (14 MBL positive isolate detected). Results: 48.84% isolates were resistant to Carbapenem and 19.76% isolates were found to be MBL producer. Colistin showed 100% susceptibility in all the MBL positive isolates. Conclusions: Among the 3 test done IMP & IMP EDTA test is easy to perform, cost effective and as sensitive as E test. Our results strongly suggest that for the MBL isolates should be detected on routine basis and the antibiotic prescribed accordingly.
ABSTRACT
Background: Enterococci causes serious infection due to its higher ability to colonize and increasing resistance to various drugs. Mutation and plasmid mediated genetic exchange are the main reason for the high rate of acquisition of antibiotic resistance. The study was aimed to determine the antibiotic resistance profile of the enterococcal isolates from various clinical samples and to detect the presence of aac (6′) Ie-aph (2″) Ia gene in the isolates which show phenotypic high level gentamicin resistance. Methods: Clinical enterococcal isolates from a tertiary care hospital in southern Delhi were subjected to antibiotic susceptibility testing. MIC for High level gentamicin was measured and the isolates were tested for presence of aac (6′) Ie-aph (2″) Ia gene by PCR. Results: Out of the total 146 Enterococcal isolates, 112 were E. fecalis, 33 were E faecium and 1 was E gallinarum. 26.02% were resistant to High level gentamicin, and 15% were resistant to streptomycin. Vancomycin resistance was 5.4%. 11 E. fecalis and 25 E. faecium isolates showed presence of aac (6′) Ie-aph (2″) Ia gene. Conclusions: High level antibiotic resistance among enterococci and the spread of vancomycin resistant is an issue of serious concern. Isolation rate of E. fecalis was much higher than E. faecium, but aac (6′) Ie-aph (2″) Ia gene was more prevalent in E.faecium. The study highlights spread of the gene aac (6′)-Ie-aph (2″)-Ia among the enterococcal isolates which can be easily transferred to other pathogenic gram positive cocci.