Misidentification of Common Pathogenic Bacteria in a University Hospital Laboratory

Accurate and definitive identification of pathogenic bacteria is essential for correct disease diagnosis, treatment of infection and trace-back of disease outbreaks associated with microbial infections. Staphylococcus epidermidis is a part of the human normal microbiota and known as opportunistic pathogen. This bacterium is the most important cause of indwelling device-related infections. Escherichia coli as a member of human and animal gut flora, is the most commonly isolated pathogen from uncomplicated urinary tract infections as well as catheter-associated urinary tract infections. The aim of this study is to report the rate of misidentification of two common bacteria in a university hospital in Isfahan.
During December 2014 and November 2015, a total of 284 E. coli and 135 S. epidermidis strains were collected from a university hospital laboratory in Isfahan. All isolated were identified using standard biochemical tests and PCR by specific primers.
The results of phenotypic and genetic testing in the laboratory were consistent with each other, but were not in agreement with results of bacterial identification in the hospital. Therefore, the results showed that 55 (19.4%) and 28 (20.7%) of strains were not E. coli and S. epidermidis, respectively.
Accurate and definitive identification of pathogenic bacteria, using standard operating procedures (SOP) in medical laboratories and providing useful therapeutic guidelines can help clinicians to remove and eradicate infections from the hospitals and community.