Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: insights from a tertiary hospital in Southern Thailand

Abstract

Broad-spectrum ampicillin-resistant and third-generation cephalosporin-resistant Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae that have pathological features in humans, have become a global concern. This study aimed to investigate the prevalence, antimicrobial susceptibility, and molecular genetic features of extended-spectrum beta-lactamase (ESBL)-producing E. coli and K. pneumoniae isolates in Southern Thailand. Between January and August 2021, samples (n = 199) were collected from a tertiary care hospital in Southern Thailand. ESBL and AmpC-lactamase genes were identified using multiplex polymerase chain reaction (PCR). The genetic relationship between ESBL-producing E. coli and K. pneumoniae was determined using the enterobacterial repetitive intergenic consensus (ERIC) polymerase chain reaction. ESBL-producing E. coli and K. pneumoniae isolates were mostly collected from catheter urine samples of infected female patients. The ESBL production prevalence was highest in the medical wards (n = 75, 37.7%), followed by that in surgical wards (n = 64, 32.2%) and operating rooms (n = 19, 9.5%). Antimicrobial susceptibility analysis revealed that all isolates were resistant to ampicillin, cefotaxime, ceftazidime, ceftriaxone, and cefuroxime; 79.4% were resistant to ciprofloxacin; and 64.3% were resistant to trimethoprim-sulfamethoxazole. In ESBL-producing K. pneumoniae and E. coli, bla_TEM (n = 57, 72.2%) and bla_CTX-M (n = 61, 50.8%) genes were prominent; however, no bla_VEB, bla_GES, or bla_PER were found in any of these isolates. Furthermore, only ESBL-producing K. pneumoniae had co-harbored bla_TEM and bla_SHV genes at 11.6%. The ERIC-PCR pattern of multidrug-resistant ESBL-producing strains demonstrated that the isolates were clonally related (95%). Notably, the presence of multidrug-resistant and extremely resistant ESBL producers was 83.4% and 16.6%, respectively. This study highlights the presence of bla_TEM, bla_CTX-M, and co-harbored genes in ESBL-producing bacterial isolates from hospitalized patients, which are associated with considerable resistance to beta-lactamase and third-generation cephalosporins.

Importance: We advocate for evidence-based guidelines and antimicrobial stewardship programs to encourage rational and appropriate antibiotic use, ultimately reducing the selection pressure for drug-resistant bacteria and lowering the likelihood of ESBL-producing bacterial infections.

Keywords: antimicrobial susceptibility analysis; enterobacterial repetitive intergenic consensus polymerase chain reaction; genetic relationship; hospitalized patients; multidrug-resistant isolates.

Fig 1

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates in a tertiary care hospital identified using multiplex PCR. Lane M, molecular marker (100–1,000 bp); lanes 1 and 2, ESBL-positive K. pneumoniae clinical strains for bla_CTX-M (588 bp); lane 3, ESBL-positive K. pneumoniae clinical strains for bla_SHV (747 bp); lanes 4 and 5, ESBL-positive K. pneumoniae clinical strains for co-harboring bla_TEM and bla_SHV (445 and 747 bp); lane 6, positive from ESBL-positive K. pneumoniae clinical strains for bla_TEM (445 bp); lanes 7–9, positive from ESBL-positive E. coli clinical strains for bla_SHV (747 bp); lanes 10–13, ESBL-positive E. coli clinical strains for bla_TEM (445 bp).

Fig 2

Dendrogram generated with ERIC-PCR data for ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates collected from a tertiary care center in Southern Thailand. Similarity of >95% was considered for clustering of isolates. The 199 pulsotypes are designated from A to B and U. ERIC, enterobacterial repetitive intergenic consensus; ESBL, extended-spectrum beta-lactamase; PCR, polymerase chain reaction.