Phenotypic Detection and Molecular Characterization of Extended Phenotypic Detection and Molecular Characterization of Extended Spectrum B-Lactamases in Enterobacteria Isolated from Khartoum Hospitals

Abstract

The presence of extended spectrum ß-lactamase (ESBL)- producing bacteria significantly affects the infection management worldwide. The objective of this study was to detect and characterize ESBL-producing enterobacteria in Khartoum hospitals. A total of 350 clinical specimens were collected from different hospitals in Khartoum State. The specimens cultivated on selective agar media. Identification was done by Gram's stain and API 20E. The presence of ESBLs was determined by double disk synergy test, combination test and E-test. The genotypic characterization of ESBLs was done by polymerase chain reaction technique. The results revealed that 125 enterobacterial species were identified. The identified bacteria include Escherichia coli 47 (37.6%), Klebsiella pneumoniae 27 (21.6%) Proteus mirabilis 10 (8%), Enterobacter cloacae 2 (1.6%), Pantoea spp. 15(12.0%), Klyvera spp. 5 (4.0%), Serratia odorifera 3 (2.4%), Serratia marcescens 2 (11.6%), Proteus vulgaris 2 (1.6%), Citrobacter spp. 4 (3.2%), Klebsiella ozania 1 (0.8%), Klebsiella oxytoca 1 (0.8%), Enterobacter sakazakii 5 (4.0%), Proteus peneri 1 (0.8%). 50(40%) species were found ESBLs-producers by double disk synergy test. 36(28.8%) of the isolates gave ESBLs positive by combination test and E-test. 40 genes (CTX-M 26(65%), TEM 8(20%) and SHV 6(15%) were detected. 3 (Proteus mirabilis, Enterobacter sakazaki and E. coli) out of 36 isolates gave ESBLs positive when tested by multiplex PCR technique.Among three species only 4 genes were detected. These genes were CTX-M( 2) and TEM (2). It is concluded that the most prevalent enterobacterial species is E. coli followed by Klebsiella pneumoniae. The two genera wer ESBL- producers. The CTX-M gene was the most common, followed by TEM and SHV. Further studies about ESBLs-producing bacteria in community setting are highly recommended.