Molecular Detection of Staphylococcus aureus Enterotoxin A to E from Different Clinical Sample in Khartoum State

Abstract

The aim of this study was to detection of Staphylococcus aureus toxin genes isolated from different clinical samples in Khartoum state by multiplex PCR assay. A total of 80 clinical specimens (30 urine, 30 wound swab and 20 blood) were collected in this study. Urine samples were culture on CLED agar, while wound swab and blood samples were culture on blood agar and MacConky agar, identification was done by catalase test, coagulase test, DNAse test and culture on manitol salt agar. Molecular confirmation was done by 16s housekeeping gene, 65 samples are found positive for 16s, while 15 samples are negative for 16s and this samples was excluded from study. Modified Kirby-bauer method was performed using the following antibiotic discs; Gentamicin, Vancomycim,, Ciprofloxacin and Methicilin. Fifty five percent of samples were found sensitive to Methicilin, 42% were sensitive to Gentamicin, 45% were sensitive to Ciprofloxacin and 38% were sensitive to Vancomycim. Guanidine hydrochloride method was adopted for DNA extraction. Finally Multiplex PCR was done for the detection of Staphylococcus aureus toxin genes (SA-A, SA-B, ENT-C, SA-D and SA-E). Most study population were females 36(55%); 19 of them suffering from UTIs, 12 suffering from wound inflation and 5 of them suffering from bacteremia, while males were 29(45%); 6 of them were suffering from UTIs, 18 of them were suffering from wound infection and 5 of them suffering from bacteremia. Among enrolled subjects, 56 were positive for one or more Staphylococcus aureus toxin genes. While 9 isolates were negative for all toxin genes. The results of multiplex PCR: five (n=5) blood samples appear as SA-A toxin gene positive and this gene was not detected in urine and wound swab samples. Nine (n=9) urine samples appear as SA-B toxin gene positive, twelve (n=12) wound swab samples appear as positive and four (n=4) blood samples appear as positive. Eleven (n=11) urine samples appear as ENT-C toxin gene positive, nine (n=9) wound swab samples appear as positive and two (n=2) blood samples appear as positive. one (n=1) urine samples appear as SA-E toxin gene positive, three (n=3) wound swab samples appear as positive and this gene was not detected in blood samples. SA-D toxin gene was not detected in any sample. The study concluded that SA-B was found predominant, and strong association (P value 0.000) between SA-A toxin gene and blood samples.