CONVENTIONAL METHODS VERSUS PCR AS A RAPID METHOD FOR MRSA IDENTIFICATION DIRECTLY FROM POSITIVE BLOOD CULTURE BROTH IN NEONATAL SEPSIS AT BENHA UNIVERSITY HOSPITAL
Sherin M. Emam1, Amal M. Saeed 1 Neveen Tawfik Abed2
Departments of ¹Microbiology&Immunology and ²Pediatric Faculty of Medicine, Benha University, Egypt
Background/Aim Neonatal septicemia remains a major cause of morbidity and mortality. Physical signs and symptoms, though useful in identifying possible cases have limited specificity. Definitive diagnosis is by bacteriologic culture of blood samples to identify organisms and establish antibiotic susceptibility. These results are usually not available promptly. So we compared conventional methods versus PCR for their ability to identify Staphylococcus species including methicillin-resistant Staphylococcus aureus (MRSA) directly from positive blood culture bottles. The aim of this study was to: identify organisms encountered in neonatal sepsis and identify MRSA directly from positive blood culture broth by the use of molecular and conventional methods. Methods: This study was carried out on 90 cases of neonatal sepsis (54 males and 36 females). The cases were admitted to the Neonatal Intensive Care Unit in Benha University Hospital. Patients were classified into two groups: Group I (early onset): included 32 cases where symptoms appeared with in 1st 72 hours after labor. Group II (late onset) included 58 cases where symptoms appeared after 72 hours of labor. Demographic, clinical and laboratory criteria were collected. Blood samples for culture were collected; full identification and antibiotic susceptibility test were done on isolated organisms. Real time PCR and slide agglutination test were done on isolated MRSA. Results: Staphylococci were detected in 40 out of 90 cases (44.4%).Coagulase positive S. aureus was detected in 29 cases out of 40 (72.5%) compared to CoNS detected in 11 cases (27.5%). MRSA was detected in 18 out of 29 cases (62.1%) by PCR compared to only 5 cases detected by latex agglutination test (17.2%).Conclusion: Phenotypic methods can be used for MRSA isolation but must be confirmed by other laboratory tests. Detection of mecA gene using PCR remains the gold standard test for MRSA isolation as there is no completely reliable phenotypic test for MRSA detection.