Biofilm Forming Ability in Multidrug-Resistant Staphylococcus aureus Strains Isolated from Local Clinical Sources

Abstract

The improper use of antibiotics is a global issue that leads to the emergence of multidrug-resistant microbes that cause a wide range of chronic and acute infections. Among these microbes, the bacteria Staphylococcus aureus represents a dangerous challenge to public health as it is responsible for life-threatening infections ranging from soft tissue infections to severe diseases. These diseases include endocarditis, pneumonia, septicemia, and catheter-related infections. Also, immunosuppression or a lengthy hospitalization can result in the progression of the invasive, opportunistic Staph. aureus. The ability of this bacterium to produce biofilm enables it to resist antibiotics. For this reason, one hundred and thirty clinical samples were collected from various clinical sources and healthcare workers in Baghdad City hospitals (Al Numan Teaching Hospital and Central Teaching Hospital Pediatric). All the isolates were identified by conventional methods (cultural, microscopic, and biochemical tests) in addition to identification by the VITEK® 2 Compact system that included several biochemical testsspecific to each bacterial species. Therefore, it can give information at the species level. Thirty isolates were tested against ten antibiotics that belonged to distinct classes (Gentamicin, Clindamycin, Azithromycin, Erythromycin, Cefoxitin, Rifampin, Ciprofloxacin, Penicillin, Ceftazidime, and Tetracycline.) The antibiotic susceptibility profiles for thirty Staphylococcus aureus isolates from various clinical samples were tested to choose the multidrug resistance isolates for further detection of the biofilm formation using the microtiter plate method. Then, the powerful biofilm producer in nine isolates was tested for the presence of biofilm genes (ica B and ica C) using a polymerase chain reaction (PCR) technique. And only eight isolates were identified to have both genes (ica B and ica C), a result that shows the differences between phenotypic and molecular detection methods.