Distribution of bla CTX − M , bla TEM , bla SHV and bla OXA genes in Extended-spectrum-β-lactamase-producing Clinical isolates: A three-year multi-center study from Lahore, Pakistan
التفاصيل البيبلوغرافية
العنوان:
Distribution of bla CTX − M , bla TEM , bla SHV and bla OXA genes in Extended-spectrum-β-lactamase-producing Clinical isolates: A three-year multi-center study from Lahore, Pakistan
Abstract Background Frequency of extended-spectrum-β-lactamase-producing clinical isolates is increasing worldwide. This is a multi-center study which was aimed to check the frequency of third-generation cephalosporin resistance and distribution of the key genetic determinants of Extended-spectrum-β-lactamase-producing Clinical isolates in Pakistan. Methods A total of 2372 samples were processed in three tertiary care hospitals and one diagnostic research center of Lahore, Pakistan during Aug-2014 to Sep-2017. Analytical profile index (API 20-E) was used for biochemical characterization of isolates. Antibiotic susceptibility testing (AST) and third generation cephalosporin resistant (3GC-R) isolates were subjected to: double disc synergism test (DDST), combination disc test (CDST) and epsilometric test (E-test) for confirmation of ESBL-production. PCR amplification of isolates with plasmid and genomic DNA was performed. Amplicon sequences were checked for gene-variants and statistical analyses were performed to check the significance of data. Results A total of 497/995 (50%) isolates including Escherichia coli 65% (n = 321), Klebsiella spp. 25% (n = 124) and Pseudomonas. 5% (n = 24), Enterobacter spp. 4% (n = 20) and Acinetobacter spp. 2% (n = 8) were screened as third generation cephalosporin resistant (3GC-R). Urine 56% (n = 278) followed by pus 20% (n = 99) and wound swab 6% (n = 29) were frequent sources. Incidence of ESBL-producers detected by combination disc test was 79% (n = 392). PCR revealed bla CTX − M (76%) gene followed by bla OXA (52%), bla TEM (28%) and bla SHV (21%) were most prevalent among ESBL-producers detected by CDST. bla CTX − M − 1(65%), bla OXA (78%) and bla TEM (57%) genes were carried on plasmids. Amplicon sequencing revealed bla CTX − M − 15 (75%), bla OXA − 1 (49%) and bla TEM − 1B (34%) and 21 (n = 28) isolates carried three genes in them. Conclusion Prevalence of ESBL-producing isolates has increased 1.13 folds during study years. Isolates had high prevalence of ESBL-encoding bla CTXM − 15 gene and narrow spectrum bla OXA − 1 and bla TEM − 1B were also prevalent.
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