High frequency and molecular epidemiology of metallo-β-lactamase-producing gram-negative bacilli in a tertiary care hospital in Lahore, Pakistan

Abstract

BackgroundMetallo-β-lactamase (MBL)-producing isolates have a strong impact on diagnostic and therapeutic decisions. A high frequency of MBL-producing gram-negative bacilli has been reported worldwide. The current study was based on determining the incidence of MBL-producing imipenem-resistant clinical isolates and investigating the β-lactamase gene variants in strains conferring resistance to a carbapenem drug (imipenem).MethodsA total of 924 gram negative isolates were recovered from a tertiary care hospital in Lahore, Pakistan, during a two-year period (July 2015 to February 2017). The initial selection of bacterial isolates was based on antibiotic susceptibility testing. Strains resistant to imipenem were processed for the molecular screening of β-lactamase genes. Statistical analysis for risk factor determination was based on age, gender, clinical specimen and type of infection.ResultsThe rate of imipenem resistance was calculated to be 56.51%. Among the 142 strains processed, the phenotypic tests revealed that the incidence of MBLs was 63.38% and 86.61% based on the combination disc test and the modified Hodge test, respectively. The frequencies of blaTEM, blaSHV, blaOXA, blaIMP-1, and blaVIM genes were calculated to be 46%, 34%, 24%, 12.5% and 7%, respectively. The co-expression of blaMBL (blaIMP and blaVIM) and blaESBL (blaTEM, blaSHV, blaOXA) was also detected through multiplex and singleplex PCR. blaOXA, blaTEM and blaSHV coexisted in 82% of the isolates. Co-expression of ESBL and MBL genes was found in 7% of the isolates.ConclusionTo our knowledge, this is the first report from Pakistan presenting the concomitant expression of blaOXA, blaTEM and blaSHV with blaIMP-1 and blaVIM in MBL-producing gram-negative bacilli.

Distribution of blaCTX − M, blaTEM, blaSHV and blaOXA genes in Extended-spectrum-β-lactamase-producing Clinical isolates: A three-year multi-center study from Lahore, Pakistan

“…The DNA used for multiplex-PCR was extracted by the heat lysis method [16]. In Multiplex-PCR, 2 μl whole cell lysate DNA for each isolate was used separately in 25 μl PCR-master mix and amplification primers as previously mentioned [16, 28, 29]. PCR amplification conditions were: Initial step of denaturation at 95°C for 5 min followed by 35 cycles of denaturation at 95°C for 1 min then annealing at 56°C for 1.5 min, extension at 95°C for 1 min and the final extension was done at 95°C for 10 min (Table 1).…”

Systematic surveillance and meta-analysis on the prevalence of Metallo-β-Lactamase producers among carbapenem resistant clinical isolates in Pakistan

“…This variation may be associated with different factors like availability and use of antibiotics, difference of nosocomial and community-based studies, and methods to determine the MBL-producers [15,16,31]. The studies that have employed molecular methods to determine the gene variants have also reported the co-existence of other beta-lactamase genes with MBL related genes [12,32,33]. This aspect of the study is in concordance with reports from different regions of the world where the simultaneous presence of other betalactam genes with metallo β-lactamase genes have been described [34][35][36].…”

“…Some of the studies included here have also reported the serine betalactamases, OXA variants, and KPCs to be the causative agents of carbapenem resistance. [12,38,39].…”

“…NDM-type, VIM-type, and IMP-type Metallo-β-lactamases (MBLs) bring them to a concern of prime attention for the region (Pakistan) [4]. Appreciable literature investigates the emergence and epidemics of new variants of MBLs at global level [8,9,6], however, the South-Asian countries hold extreme vulnerability [10][11][12].…”

Detection of New Delhi metallo-beta-lactamase enzyme gene bla NDM-1 associated with the Int-1 gene in Gram-negative bacteria collected from the effluent treatment plant of a tuberculosis care hospital in Delhi, India

“…NDM-1, 2, 3, 4 [14][15][16]) and the genes encoding them (bla NDM-1, 2, 3 ). Bacterial strains which are positive for bla NDM (genotypic resistance marker gene) and also produce NDM enzymes are particularly dangerous because, (1) There is no routine standard phenotypic test for MBL detection; (2) Consequently there is a possibility of high prevalence of unrecognized asymptomatic carriers amongst general population; (3) There is lack of effective antibiotics against NDM-1-positive superbugs; and (4) Plasmids from these bacteria can undergo wide rearrangement and thus can cause widespread horizontal transmission of the antibiotic resistance gene (bla NDM-1 ) [17][18][19][20].…”