occurrence and antibiogram of extended-spectrum cephalosporin- and cephamycin-resistant escherichia coli in asymptomatic university students

Background: apparently healthy individuals could serve as reservoirs and disseminators of extended-spectrum 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.