Multidrug-resistantPseudomonas aeruginosastrains harbouring R-plasmids and AmpC β-lactamases isolated from hospitalised burn patients in a tertiary care hospital of North India

Abstract

The present study was designed to determine resistance rates and patterns in Pseudomonas aeruginosa isolates obtained from hospitalised burn patients in an Indian tertiary care hospital. To that end, we isolated plasmid(s) from the multidrug-resistant isolates, demonstrated the plasmid-mediated resistance by curing and transformation experiments, and screened all the isolates for the occurrence of AmpC L-lactamases. Thirty isolates of P. aeruginosa were analysed for the presence of antibiotic resistance. Plasmid-curing experiments and AmpC L-lactamase detection were performed on all the isolates and seven isolates showing the most common antibiotic resistance pattern were selected for plasmid isolation and transformation experiments. All 30 isolates were multidrug-resistant and the majority (83.3%) of isolates were resistant to seven or more antibiotics, out of 11 antibiotics tested including anti-pseudomonal and non-antipseudomonal antimicrobial drugs. The most striking feature was the presence of resistance to amikacin. A 48.5-kb plasmid was isolated from the isolates. Curing and transformation experiments showed that resistance to amikacin was plasmid-mediated. Phenotypic screening for the occurrence of AmpC L-lactamases showed that 20% of isolates were AmpC producers whereas 10% of isolates were characterised as 'indeterminate' for AmpC enzyme. In conclusion, a markedly high (56.7%) resistance to amikacin was noted in the present study. Amikacin resistance was determined to be plasmid-encoded and the presence of an AmpC L-lactamase was inferred in 20% of isolates. This is among the first reports regarding the emergence of plasmid-mediated resistance to amikacin and the occurrence of AmpC L-lactamases in P. aeruginosa strains from India.

Plasmid Profile Analysis and bla VIM Gene Detection of Metalo β-lactamase (MBL) Producing Pseudomonas aeruginosa Isolates from Clinical Samples

“…Pseudomonas aeruginosa plays an important aetiological role in human infections as many clinical isolates are resistant to common antibiotics [14,15]. The prevalence of P.aeruginosa infection in our study 316/2076 (15.22%) were similar to (18.2%) studies of Gad et al, [16].…”

Occurrence of Plasmid-Mediated AmpC β-Lactamases Among Escherichia coli and Klebsiella pneumoniae Clinical Isolates in a Tertiary Care Hospital in Bangalore

“…and 37% of E. coli in Chennai [23]. Around the same time, Shahid et al reported 20 P. aeruginosa isolates as producing AmpC beta lactamases in Aligarh [18]. In 2005, data from Chennai revealed AmpC production in 20.8% Klebsiella spp.…”

“…Plasmid curing experiments was also preformed as described by Shahid et al [18]. Ethidium bromide was used as the curing agent.…”

Study on drug resistance of Pseudomonas aeruginosa plasmid-mediated AmpC β-lactamase

“…A limited number of studies have analyzed drug resistance in P. aeruginosa plasmid-mediated AmpC β-lactamase. In 2003, Shahid et al (23) isolated P. aeruginosa strains exhibiting plasmid-mediated AmpC enzyme from burns patients in an intensive care hospital in Northern India. In the domestic environment, a single strain of E. coli was previously observed to exhibit ACT-1 plasmid AmpC enzyme.…”