Prevalence and characterization of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolated from raw vegetables retailed in Southern Thailand

Chonticha Romyasamit; Phoomjai Sornsenee; Siriphorn Chimplee; Sitanun Yuwalaksanakun; Dechawat Wongprot; Phanvasri Saengsuwan

doi:10.7717/peerj.11787

Prevalence and characterization of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolated from raw vegetables retailed in Southern Thailand

PeerJ. 2021 Aug 25:9:e11787. doi: 10.7717/peerj.11787. eCollection 2021.

Authors

Chonticha Romyasamit^#¹, Phoomjai Sornsenee^#², Siriphorn Chimplee³, Sitanun Yuwalaksanakun¹, Dechawat Wongprot¹, Phanvasri Saengsuwan³

Affiliations

¹ Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand.
² Department of Family and Preventive Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
³ Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.

^# Contributed equally.

Abstract

Background: The increasing prevalence of broad-spectrum ampicillin-resistant and third-generation cephalosporin-resistant Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae, has become a global concern, with its clinical impacts on both human and veterinary medicine. This study examined the prevalence, antimicrobial susceptibility, and molecular genetic features of extended-spectrum β-lactamase (ESBL)-producing E. coli and K. pneumoniae isolates from 10 types of raw vegetables.

Methods: In total, 305 samples were collected from 9 markets in Nakhon Si Thammarat, Thailand, in 2020.

Results: ESBL-producing E. coli and K. pneumoniae isolates were found in 14 of the 305 samples obtained from 7 out of 10 types of vegetables (4.6% of the total). Further, 14 ESBL-producing E. coli (n = 5/14) and K. pneumoniae isolates (n = 9/14) (1.6% and 3.0%, respectively) were highly sensitive to β-lactam/carbapenem antibiotics (imipenem, 100%). ESBL-producing E. coli (n = 4) and K. pneumoniae isolates (n = 8) were also sensitive to non-β-lactam aminoglycosides (amikacin, 80.00% and 88.89%, respectively). ESBL producers were most resistant to β-lactam antibiotics, including ampicillin (85.71%) and the cephalosporins cefotaxime and ceftazidime (64.29%). The most frequently detected gene in ESBL-producing E. coli and K. pneumoniae was bla_SHV . However, two ESBL-producing E. coli isolates also carried three other ESBL-encoding variants, bla_TEM , bla_CTX-M1 , bla_GES and bla_TEM, bla_SHV, bla_CTX-M9 , which may be due to their association with food chains and humans.

Discussion: Indeed, our results suggest that raw vegetables are an important source of ESBL-resistant E. coli and K. pneumoniae, which are potentially transmittable to humans via raw vegetable intake.

Keywords: Antibiotic resistance; ESBL-producing bacteria; Escherichia coli; Klebsiella pneumoniae; Vegetables.

Grants and funding

This work was supported by the Research Institute for Health Sciences, Walailak University [grant number; WU-IRG-63-085]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.