Phenotypic and genotypic detection of carbapenemase enzymes producing gram-negative bacilli isolated from patients in Khartoum State

Abstract

Background : Carbapenems are used as antibiotics of last resort for treating infections due to multidrug-resistant Gram-negative bacilli, but emergence of Carbapenem resistant Gram-negative bacilli have been reported due to the production of Carbapenemase enzymes that significantly limits treatment options for life-threatening infections. Objective : This study aimed to detect Carbapenem resistant Gram-negative bacilli from patients attended to different hospitals in Khartoum state and to detect Carbapenemase enzymes production by phenotypic and genotypic methods. Methods : A hospital based cross sectional study was conducted in Khartoum state in the period from February to August 2016. Hundred and forty nine Gram-negative bacilli bacteria were isolated from different clinical specimens. Blood agar, Chromogenic agar media, MacConkey agar, XLD mediaandstandard biochemical tests were used for isolation and identification of Gram-negative bacilli from different samples. Standard antimicrobial susceptibility testing to Carbapenem antibiotic was performed for all isolates, then detection of Carbapenemase enzymes production for the resistant isolates was performed using Modified Hodge Test  and PCR. Results : Hundred and forty nine Gram-negative bacilli were isolated from 147 different clinical specimens. The most predominant Gram-negative bacilli isolates was  E.coli (54.4%), followed by Klebsiella species (29.5%). More than fifty percent of the isolates were Carbapenem resistant. Fifty six percent of the resistant isolates were positive  by Modified Hodge Test . By using PCR, 17.3% of resistant organisms were harbored bla OXA48 gene, and 6.7% harbored bla IMP gene. E.coli was the most bacteria that harbored the bla oxa48 followed by Klebsiella species. bla IMP gene was harbored only by E.coli . Conclusion : The percentage of resistance to Carbapenems due to production of Carbapenemase enzymes is very high in Sudan.Bla OXA48 gene is more predominant than bla IMP in this study.