MINIMUM INHIBITORY CONCENTRATIONS OF CEPHALOSPORIN ANTIBIOTICS FOR FECAL AND URINARY ESCHERICHIA COLI FROM UNIVERSITY STUDENTS IN KEFFI, NIGERIA

Minimum inhibitory concentration (MIC) provides in-vitro justification for confirming antibiotic resistance strains. This study evaluated the MICs of cephalexin, cefuroxime, ceftazidime and cefepime for Escherichia coli isolated from urine and stool of university students in Keffi. Eighty bacteria (thirty from urine, fifty from stool) were isolated and identified as E. coli from students by cultural, microscopic and biochemical methods. MICs were evaluated using macro-broth dilution method and breakpoint susceptibility interpreted as described by Clinical and Laboratory Standards Institute (CLSI) of the United States of America (USA). The isolates were also screened for carriage of extended spectrum beta-lactamase (ESBL). The antibiotic susceptibility level and MIC for 50% of the isolates (MICso) from urine was: cephalexin (0% and 45.8 pg/ml), cefuroxime (0% and 64.0 pg/ml), ceftazidime (20% and 18.4 pg/ml) and cefepime (47% and 13.8 pg/ml). Fecal isolates had susceptibility and MICso os follows: cephalexin (8% and 34.2 pg/ml), cefuroxime (20% and 32.0 pg/ml), ceftazidime (32% and 8.0 pg/ml) and cefepime (46% and 4.8 pg/ml). With the exception of cefuroxime, the differences in MICso values of each cephalosporin antibiotics tested for urine and stool isolates were insignificant. For both urinary and faecal isolates, MIC for 90% of the isolates (MIC9Q) decreased in the order: cefepime < ceftazidime < cefuroxime and cephalexin. This study revealed high susceptibility pattern of urinary and faecal E. coli isolates from apparently healthy individual to a fourth generation cephalosporin cefepime. Furthermore, all isolates are potential carriers of extended spectrum beta-lactamases. Further investigation is required to confirm the isolates as ESBL carriers.