Molecular detection of Extended-spectrum β-lactamase genes in E. coli Isolated from Urine Specimens

Abstract

The aim of this study was to detect and characterizing ESBLs producing E.coli isolated from clinical specimens from Wad Alabass Specialized Hospital, Sennar State in the period from March 2011 to June 2012. A total of 500 urine samples were collected and cultured on MacConkey's agar and blood agar. Identification of the causative bacteria, was done by growth criteria on media, Gram's stain and biochemical tests. 332/500(66.4%) samples gave growth while the rest not grown. The Gram-negative bacilli were 232/332(69.9%), 93/332(28%) were Gram-positive cocci and 7/332(2.1%) were yeast cells. 133/332(40%) were E. coli, 33/332(10%) K. pneumoniae, 39/332(12%) Proteous spp, and 27/332(8%) Pseudomonas aeruginosa. ESBL production tests were done for all E. coli isolates, initially screened by cefotaxime and ceftazidime, where 62(46.6%) isolates gave positive result by both, then confirmed by combination test by using cefotaxime and ‫‪ceftazidime with and without clavulanic acid, 48/62(77.4%) isolates gave positive result‬‬ ‫-‪by both. The PCR was performed For all E. coli isolates by using SHV, TEM and CTX‬‬ ‫‪M primers. CTX-M genes were the most predominant genes 30/46(65.22%) followed‬‬ ‫.‪by TEM gene 13/46(28.26%), and the least one was SHV gene 3/46(6.52%) genes‬‬ ‫‪This study concluded that E. coli bacterium is the most predominant one and confirmed‬‬ ‫‪that CTX-M genes is the most spreading and predominant ESBLs genes followed by‬‬ ‫.‪TEM and SHV genes‬‬