Antibiotic Sensitivity And Molecular Characterization Of Bacterial Isolates From Human Blood Samples

Abstract

Many hospital-acquired infections occur because of the invasive treatments that are often needed in hospitalized patients. For example, intravenous catheters used for fluid administration, catheters placed in the bladder for urine drainage and breathing tubes for people on a breathing machine can all increase the susceptibility to infectious agents, especially bacteria. Blood samples from the subjects of this study were analyzed for presence of bacterial pathogens such as E. coli, K. pneumonia, and Staphyloccocus species. More than hundred clinical bacterial isolates were accurately identified using classical methods for discrimination and speciation of bacteria. These methods are routinely used to provide discriminating information. Additionally, molecular biology techniques such as plasmid fingerprints, RAPD-PCR and total protein-banding pattern analysis are now commonplace in bacterial identification, not only in the clinical laboratory but also in academic setup. Using these techniques the clinical isolates were grouped into three major genera of E. coli, K. pneumonia, and two Staphyloccocus species. The antibiotic sensitivity patterns of the four bacteria genera can be classified as follow: S. aureus was only sensitive to amoxicillin+clavulanic acid (AMC), S. epidermides was resistant to five antibiotics ( AMC, Amoxicillin (AML), piperacillin (PRL), cefotaxime (CTX) and ceftazidime (CAZ)), E. coli showed the same antibiotic resistance pattern as S. epidermides except it was sensitive to ceftazidime (CAZ), whereas, K. pneumoniae was resistant to all antibiotics used in this assay. The antibiotic sensitivity data and the molecular identification are highly important, not only for prescription of right medication, but also for accuracy of naming the clinical isolates.

New Egyptian Journal of Microbiology Vol. 17 (2) 2007: pp. 314-326