Occurrence and Antibiogram of ExtendedSpectrum Cephalosporin and CephamycinResistant Escherichia coli in Asymptomatic University Students

Background: Apparently healthy individuals could serve as reservoirs and disseminators of extendedspectrum cephalosporin (ESC) and cephamycin (cefoxitin, FOX)resistant, and extendedspectrum βlactamaseproducing (ESBLP) 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 FOXresistant and ESBLP 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. ESCresistant 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 AmpCproducers) but none produced ESBL. The resistance of the isolates was 100% to ampicillin (AMP), 95% to ceftazidime (CAZ), tetracycline (TET) and sulfamethoxazoletrimethoprim (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 FOXresistant 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.