Carbapenem resistance mechanisms among blood isolates of Klebsiella pneumoniae and Escherichia coli

Abstract

The purpose of this study was to characterize the different mechanisms of carbapenem resistance among blood isolates of Klebsiella pneumoniae and Escherichia coli. Meropenem resistant isolates were included. Antimicrobial susceptibility testing, phenotypic and genotypic detection of carbapenemase production were performed. Genetic relatedness of bla NDM-1 producers was determined by pulsed-filed gel electrophoresis (PFGE) typing. The relatedness of bla NDM-1 carrying plasmids was studied by plasmid restriction fragment length polymorphisms (pRFLP) and polymerase chain reaction (PCR) based replicon typing (PBRT). For the carbapenem gene negative isolates, other possible mechanism of carbapenem resistance such as role of outer membrane porin loss with ESBL or AmpC production, and efflux pumps were analyzed. Among the 162 isolates studied, 1 (0.6%) was found to be bla KPC-3 producer and 42.5% were bla NDM-1 producers. All the isolates were multidrug resistant; two isolates carried both bla NDM-1 and bla VIM-2. PFGE determined bla NDM-1 producers were non-related. The plasmids harbouring bla NDM-1 belonged to two major incompatibility plasmid types, IncL/M and IncA/C. IncL/M is a novel plasmid group reported firstly from this region. A clonal outbreak of bla IMP-1 K. pneumoniae was identified during this study. This is the first report on the emergence of K. pneumoniae producing bla IMP-1 from South India and bla KPC-3 from India. The study suggest including ertapenem in the routine susceptibility screening to find the true rate of KPC producers in Indian hospitals. Colistin and tigecycline are two drugs that have activity but both have developed resistance. Selection of an appropriate initial antibiotic regimen for empiric therapy, rotation of different antibiotic classes and judicious use of antibiotics are essential.

Phenotypic detection of carbapenem resistance in gram negative bacilli from various clinical specimens of a tertiary care hospital in Western Uttar Pradesh

“…15 In another study Mohamudha RP et al, also found that the distributions of the sources of the isolates were: urine 37% (n=39), blood 22.3% (n=23), wound discharge 11.7% (n=12), peritoneal fluid 5.8% (n=6), ascitic fluid 10.7% (n=11), tracheal aspirate 6.8% (n=7), and sputum 4.9% (n=5). 16 Nagaraj S et al, had comparable findings where they observed that the carbapenem-resistant organisms were isolated mainly from urine samples up to 42% (n = 21), followed by wound discharge 18% and respiratory secretions 16%. 17 The MHT screening test for carbapenems is currently proposed by the clinical and laboratory standards institute (CLSI) for phenotypic screening of carbapenemases producers.…”

Prevalence of Carbapenem Resistance among Gram-Negative Bacteria in a Tertiary Care Hospital in North-East India

“…In a study by Amjad A et al 24 out of 100 isolates which were carbapenem intermediate or sensitive, 69% showed the presence of carbapenemase by MHT which is similar with this study. In the study by Mahajan G et al 16 47.6% of the isolates were found to produce carbapenemase enzyme by MHT and the remaining 22 strains were found to be carbapenemase negative. In a study by Rajkumar MS et al 25 among the thirty seven meropenem resistant isolates, MHT was positive for 91.89% of the isolates.…”

“…Resistance to carbapenem in this study is low compared to studies by various authors from India. In a study by Bijayini Behera et al 16 at the All India Institute of Medical Sciences, New Delhi, carbapenem resistance was found to be 69%, which much on the higher side.…”

Antimicrobial resistance of Escherichia coli isolates from spray-chilled sheep carcasses during cooling

“…Studies performed by Rahamathulla et al (2016) showed that resistance to meropenem is an increasing public health problem because this antibiotic is one of the last resources for the treatment of infections in hospitals. Rasmussen et al (1996) reported that this serious problem is associated with genes encoding carbapenemases on plasmids or transposons in carbapenem-resistant bacteria.…”