Endotracheal tube tip culture in post-operative respiratory infections in open heart surgery patients: a one year prospective study

Background: Respiratory tract infections are a common occurrence after open heart surgery, leading to prolonged hospital stay, morbidity and costing the hospital exchequer. This study was conducted to study the utility of postextubation endotracheal tube [ET] tip culture in providing an early-basis for starting evidence-based antibiotic therapy. Methods: We retrospectively reviewed the case records of 172 patients who had undergone heart surgery at our tertiary care teaching hospital for occurrence of post-operative infections from clinical and microbiological data. Results: Bacterial culture was positive in 67(39%) patients. Endotracheal tube patients, grew organisms that were sensitive to empirical antibiotic therapy, in 39 (58%) patients. In 28 (42%) patients organisms resistant to empirical therapy were grown; only 14 of the 28 patients (50%) were symptomatic. Staphylococcus was the most common organism isolated followed by Acinetobacter and Enterobacter. Pseudomonas aeruginosa isolates were sensitive to all the antibiotics tested. Resistance was high among Acinetobacter sp. All the Gram-negative bacteria were sensitive to tigecycline. Resistance for beta-lactam antibiotics ranged from 35%-66% with imipenem being the most effective antibiotic. Conclusion: Our observations provide useful information regarding the microbiology of respiratory infection occurring in post-operative patients who had undergone open-heart surgery. Post-extubation endotracheal tip culture appears to be a useful tool for reliable and accurate diagnosis and treatment of these infections.