Isolation and Identification of Serratia marcescens from Suspected Late Neonatal Sepsis in Intensive Care Unit

Background: Neonatal sepsis stays one of the main sources of morbidity and mortality both among infant in ICU, in light of the planning of the disease neonatal sepsis has been categorized into early and late-onset sepsis, where the latter occurs after one week of life and is often more insidious in onset than the former. Objective: To detect the rate of Serratia marcescens infection in neonatal sepsis in ICU by molecular technique. Methods: A total of 50 neonates with the age group 8 days to 30 days who were admitted to AL-Kadhumiya Teaching Hospital/ Baghdad during the period January to March ,2017 were recruited for this cross-sectional study. Approximately 3 ml of venous blood were obtained from each patients. These samples were examined for septicemia by blood culturing followed by API20 for quick identification of relevant bacteria. Furthermore, bacteria DNA was isolated directly from blood samples, and conventional PCR based on luxS gene, highly specific to S. marcescens, was achieved. Results: Blood culture were positive in 36(72 %) out of 50 samples; the most common bacterial causes were Staphylococcus aureus (18.7%), Pseudomonas aeruginosa (13.8%) and Serratia marcescens (11.1%), Molecular method revealed specific amplification of luxS gene in 12 samples (24%). Conclusion: Serratia marcescens has risen as a most widely recognized causative agent in late onset sepsis.