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 ß-lactamase (ESBL) genes. Semi-quantitative reverse transcription PCR (RT-PCR) was optimised to evaluate oprD deficiency. Efflux pump activity was determined by phenylalanine-arginine ß-naphthylamide (PAßN) 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.
Subject(s)
Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Drug Resistance, Multiple, Bacterial , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/pathogenicity , Virulence Factors/genetics , Biological Transport, Active , Gene Expression Profiling , Genes, Bacterial , Humans , India , Membrane Transport Proteins/analysis , Prevalence , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/isolation & purification , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Tertiary Care Centers , VirulenceABSTRACT
Objective: To report our experience with two tests, anti-cardiolipin antibody test [venereal disease reasearch laboratory (VDRL) test] and specific treponemal test (Treponema pallidum hemagglutination assay), used for screening antenatal, high risk cases and cases from sexually transmitted infection in a tertiary care hospital from January 2006 till December 2008. Methods: A total of 14 639 samples received from various patient groups including antenatal cases, patients attending sexually transmitted disease (STD) clinic, blood donors and HIV positive patients were screened. Results: Among the 14 639 samples collected, 103 were positive by VDRL test. Of these 89 cases were confirmed by quantitative VDRL test and Treponema pallidum hemagglutination assay. The cumulative seroprevalence over two years was found to be 0.61% in this study. The syphilis seroprevalence reduced from 0.88% in 2006 to 0.40% in 2008. Among the various sub-populations studied, patients attending the sexually transmitted infection clinic showed a seroprevalence of 2.62%. The seroprevalence decreased significantly from 4.00% in 2006 to 1.39% in 2008. Conclusions: Our study showed a statistically significant declining rate of syphilis in STD clinics as well as the overall seroprevalence. These findings could be interpreted as indicators of improved programmes for prevention and management of STDs.