Kalaiarasan Ellappan1, Harish Belgode Narasimha2, Saravana Kumar3. 1. Department of Microbiology, Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER), Puducherry 605006, India. Electronic address: nasaralak@gmail.com. 2. Department of Microbiology, Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER), Puducherry 605006, India. 3. Department of Biostatistics, Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER), Puducherry 605006, India; Present address: Department of Biostatistics, National Institute of Epidemiology (NIE), ICMR, Chennai, Tamil Nadu, India.
Abstract
OBJECTIVES: This study aimed to identify the multiple drug resistance mechanisms and various virulence genes in high-level carbapenem-resistant Pseudomonas aeruginosa (CARPA) isolates collected from patients hospitalised in a tertiary care hospital in South India. METHODS: A total of 156 CARPA isolates were included in the study. Multiplex PCR was optimised to detect carbapenemase and extended-spectrum β-lactamase (ESBL) genes. Semi-quantitative reverse transcription PCR (RT-PCR) was optimised to evaluate oprD deficiency. Efflux pump activity was determined by phenylalanine-arginine β-naphthylamide (PAβN) assay, and expression of mexA and mexC genes was evaluated by real-time quantitative PCR (qRT-PCR). Presence of the virulence genes exoS, algD, algU, lasR and rhlR were detected by qRT-PCR and plcH and lasB by RT-PCR. RESULTS: Genes encoding carbapenemases and ESBLs were detected in 48.7% (blaVIM, 23.1%; blaNDM-1, 17.3%; blaVIM+blaNDM-1, 7.1%; and blaIMP, 1.3%) and 4% (blaVEB, 4.5%) of CARPA isolates, respectively. Loss of porin OprD was observed in nine isolates (5.8%), two of which harboured the blaVIM gene. Among efflux pump-positive isolates, mexA expression was significantly upregulated. algD expression was detected in 93% of CARPA isolates, followed by algU (89%), rhlR (84%), lasR (81%) and exoS (76%). The lasB and plcH genes were detected in 94% and 92% of isolates, respectively. CONCLUSIONS: Co-existence of multiple antimicrobial resistance mechanisms together with virulence genes in carbapenem-resistant isolates has become an alarming emerging threat. Continuous monitoring of multidrug-resistant pathogens is important for clinicians in order to determine therapeutic options against such infections.
OBJECTIVES: This study aimed to identify the multiple drug resistance mechanisms and various virulence genes in high-level carbapenem-resistant Pseudomonas aeruginosa (CARPA) isolates collected from patients hospitalised in a tertiary care hospital in South India. METHODS: A total of 156 CARPA isolates were included in the study. Multiplex PCR was optimised to detect carbapenemase and extended-spectrum β-lactamase (ESBL) genes. Semi-quantitative reverse transcription PCR (RT-PCR) was optimised to evaluate oprD deficiency. Efflux pump activity was determined by phenylalanine-arginine β-naphthylamide (PAβN) assay, and expression of mexA and mexC genes was evaluated by real-time quantitative PCR (qRT-PCR). Presence of the virulence genes exoS, algD, algU, lasR and rhlR were detected by qRT-PCR and plcH and lasB by RT-PCR. RESULTS: Genes encoding carbapenemases and ESBLs were detected in 48.7% (blaVIM, 23.1%; blaNDM-1, 17.3%; blaVIM+blaNDM-1, 7.1%; and blaIMP, 1.3%) and 4% (blaVEB, 4.5%) of CARPA isolates, respectively. Loss of porin OprD was observed in nine isolates (5.8%), two of which harboured the blaVIM gene. Among efflux pump-positive isolates, mexA expression was significantly upregulated. algD expression was detected in 93% of CARPA isolates, followed by algU (89%), rhlR (84%), lasR (81%) and exoS (76%). The lasB and plcH genes were detected in 94% and 92% of isolates, respectively. CONCLUSIONS: Co-existence of multiple antimicrobial resistance mechanisms together with virulence genes in carbapenem-resistant isolates has become an alarming emerging threat. Continuous monitoring of multidrug-resistant pathogens is important for clinicians in order to determine therapeutic options against such infections.
Authors: Sreeja K Vamsi; Rama S Moorthy; Mary N Hemiliamma; Rama B Chandra Reddy; Deepak J Chanderakant; Shravani Sirikonda Journal: Saudi Med J Date: 2022-03 Impact factor: 1.422