Antimicrobial resistance of fecal isolates of salmonella and shigella spp at bahir dar regional health research laboratory, northwest Ethiopia

Abstract

Salmonellosis and Shigellosis coupled with increased levels of multidrug resistances are public health problems, especially in developing countries. This study was aimed at determining the prevalence of fecal Salmonella and Shigella spp and its antimicrobial resistance patterns. A retrospective study was conducted on 1321 stool cultures that were processed at Bahir Dar Regional Health Research Laboratory from September 2003 to June 2008. Antibiotic susceptibility tests were performed using the disc diffusion method. The isolation rate of Salmonella and Shigella spp were 84 (6.4%) and 45 (3.4%), respectively. Salmonella spp exhibited very high levels of antimicrobial resistance (80-90%) to ampicillin, cephalotin, chloramphenicol, co-trimoxazole, erythromycin, streptomycin and tetracycline (44%). A high proportion of Shigella isolates were resistant to ampicillin (93.3%), chloramphenicol (42.2%) co-trimoxazole (62.2%) and tetracycline (95.5%). Shigella and Salmonella spp exhibited the lowest resistance rate to gentamicin and norfloxacillin. The overall multiple antimicrobial resistance was 98.2%. These data indicate that a high proportion of fecal Shigella and Salmonella spp are resistant to the most commonly prescribed antimicrobials with the least resistance to gentamicin and norfloxacillin. Antimicrobial susceptibility tests therefore need to be performed prior to prescribing antimicrobials. Furthermore, a regular antimicrobial surveillance and adherence to the antimicrobial policy may help to contain the spread of antimicrobial  esistant enteric bacterial pathogens.

Keywords: multidrug resistance, Salmonella spp, Shigella spp, stool culture, northwest Ethiopia