Occurrence and Antibiogram of Extended-Spectrum Cephalosporin- and Cephamycin-Resistant Escherichia coli in Asymptomatic University Students

Madubuike Umunna Anyanwu,Chiamaka Felicitas Okpalanwa,Raymond Nduka Ugwuanyi

doi:10.15171/ijep.2019.09

Madubuike Umunna Anyanwu, Chiamaka Felicitas Okpalanwa + Show 1 more

Open Access

https://doi.org/10.15171/ijep.2019.09

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Abstract

Background: Apparently healthy individuals could serve as reservoirs and disseminators of extendedspectrum cephalosporin (ESC)- and cephamycin (cefoxitin, FOX)-resistant, and extended-spectrum β-lactamase-producing (ESBL-P) Escherichia coli which jeopardizes antibacterial therapy thereby posing a threat to the health of infected individuals/carriers. Objectives: This study aimed to screen healthy asymptomatic students in the University of Nigeria, Nsukka (UNN) as potential reservoirs of ESC- and FOX-resistant and ESBL-P E. coli and to determine the antibacterial resistance profile. Materials and Methods: Anal swabs were collected from 190 randomly selected healthy asymptomatic students of both genders in UNN between March and July 2018. ESC-resistant E. coli was isolated using MacConkey agar with 2 µg/mL ceftazidime. ESBL production was assessed by combination disc method while cephamycin resistance was determined using cefoxitin disc screening. Phenotypic resistance of the isolates was determined using disc diffusion method. Results: Out of 190 samples, 20 (10.2%) demonstrated growth. Of these, 6 (30%) were FOX resistant (putative AmpC-producers) but none produced ESBL. The resistance of the isolates was 100% to ampicillin (AMP), 95% to ceftazidime (CAZ), tetracycline (TET) and sulfamethoxazole-trimethoprim (SXT), 30% to FOX and chloramphenicol (CHL), 85% to ciprofloxacin (CIP), enrofloxacin (ENR) and streptomycin (STR), and 65% to kanamycin (KAN). All the isolates were susceptible to meropenem (MEM). Among the 20 isolates, 1 (5%) was resistant to 2 classes of antibacterial agents while 19 (95%), including all the FOX-resistant strains, were resistant to ≥ 3 classes of antibacterial agents. The isolates exhibited 11 multiple antibacterial resistance patterns with AMP, CAZ, FOX, TET, CIP, ENR, STR, KAN, SXT being predominant. Conclusion: Healthy asymptomatic students in UNN are potential reservoirs and disseminators of ESC- and cephamycin (FOX)-resistant E. coli.

Highlights

Healthy individuals could serve as reservoirs and disseminators of extendedspectrum cephalosporin (ESC)- and cephamycin-resistant, and extended-spectrum β-lactamase-producing (ESBL-P) Escherichia coli which jeopardizes antibacterial therapy thereby posing a threat to the health of infected individuals/carriers
It suggested that either the students already harbored these organisms in their gut or they acquired them from their environment.[10]. It suggested selection of CTZ probably due to the frequent use of 3GCs in the sampled individuals. This finding of ESC-resistant E. coli in healthy students calls for concern because these students are putative reservoirs and disseminators of these organisms into the environment, thereby posing a threat to the health of individuals that get in direct and/ or indirect contact with them.[5,12]
This study has shown that ESC- and FOX-resistant E. coli are harbored by a sizeable percentage (10.5%) of asymptomatic healthy students in UNN colonization of healthy students in UNN by ESBL-P E. coli strains seems to be uncommon

Summary

Introduction

Healthy individuals could serve as reservoirs and disseminators of extendedspectrum cephalosporin (ESC)- and cephamycin (cefoxitin, FOX)-resistant, and extended-spectrum β-lactamase-producing (ESBL-P) Escherichia coli which jeopardizes antibacterial therapy thereby posing a threat to the health of infected individuals/carriers. Inappropriate use of any ESC and/or non-ESCs β-lactams stimulates resistance against all generations of cephalosporins in Enterobacterales.[5,7] There is increased interest in ESC- and cephamycin-resistant E. coli strains because these organisms jeopardize ESC/cephamycin therapy, and exhibit resistance to all β-lactams (except carbapenems) and other classes of antibacterial agents including chloramphenicol (CHL), fluoroquinolones, trimethoprim and sulphonamide.[8,9,10] The World Health Organization (WHO) recently classified ESC-/ cephamycin-resistant Enterobacterales as “critical priority 1 pathogens” that pose a threat to human and animal

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