Isolation and Antimicrobial Susceptibility Test of Bacterial Pathogens in Patients with Acute Diarrhea

Abstract

The study was conducted in Khartoum State during the period from November 2008 to April 2009, to isolate bacteria that cause acute diarrheal diseases in patients who have no previous history of diarrhea and to determine antimicrobial sensitivity of the isolated pathogens. A total of two hundred diarrheal specimens were collected from Gaffar Ibn Auf Specialized hospital for Children (GIASH), Bashair Teaching Hospital and Alban Jadeed Teaching Hospital. The specimens were transported in transport medium and inoculated into a variety of selective media for primary isolation of pathogens. The bacteria identification was done by API 20 E and slide agglutination test. Modified Kirby-Bauer disc diffusion method was adopted to determine sensitivity of isolates to traditionally used antimicrobial agents. E test was adopted to determine the MIC of chloramphenicol, tetracycline, gentamicin, ciprofloxacin, ceftazidime and co- trimoxazole. The results showed that Escherichia coli represent 57%, Salmonella typhi represent 2.5%, in which resistance rate was (100%) to tetracycline and ceftazidime, (60%) to co-trimoxazole, nalidixic acid and amoxicillin, (0%) to ciprofloxacin, gentamicin, ceftriaxone and chloramphenicol. Shigella sonnei represent 2.0% and resistance rate was (100%) to co-trimoxazole, tetracycline and amoxicillin, (50%) to ceftazidime and (0%) to ciprofloxacin, chloramphenicol, gentamycin, ceftriaxone and nalidixic acid. S. typhi MIC ranges to chloramphenicol were (0.1–0.5 μg/ml), tetracycline were (10-60 μg/ml), MIC range of gentamicin (0.1–0.25 μg/ml), MIC range of ciprofloxacin (0.004 -0.008 μg/ml), the MIC range of ceftazidime (1–7.5 μg/ml), MIC50 and MIC90 were 30μg/ml to tetracycline, 0.004μg/ml to ciprofloxacin, 0.1μg/ml to gentamicin respectively, 0.1μg/ml to chloramphenicol, and the MIC50, MIC90 of ceftazidime were 1μg/ml and 3μg/ml respectively. Shigella sonnei MIC ranges of tetracycline were (120 – >240 μg/ml), were (5–7.5 μg/ml) to ceftazidime, (0.01–2 μg/ml) to ciprofloxacin and (4 - >240 μg/ml) to co-trimoxazole. The MIC50 and MIC90 were 120 μg/ml and >240 μg/ml to tetracycline, 5.0 μg/ml and 7.5 μg/ml to ceftazidime, 0.01 μg/ml and 0.1 μg/ml to ciprofloxacin, > 240 μg/ml to co-trimoxazole respectively. The study concluded that responsibility of Salmonella typhi and Shigella sonnei in diarrheal disease was slightly high and resistance to antimicrobial agents also high.