Does organophosphorus poisoning increase the risk of staphylococcal ventilator associated pneumonia? – a retrospective study

Introduction: The aim of this study was to determine the clinical predictors of staphylococcal ventilator-associated pneumonia (VAP) and to compare the outcomes of staphylococcal VAP with non-staphylococcal VAP. Methodology: A retrospective observational study was conducted among adult patients admitted to the medical intensive care unit (MICU) in a tertiary care hospital in India from January 2017 to December 2019. The patients were grouped based on their diagnosis into staphylococcal and non-staphylococcal VAP, and the baseline characteristics, clinical parameters, co-morbidities, and outcome parameters were compared. Results: Out of 2129 MICU admissions, 456 patients with microbiologically confirmed VAP were included, of which 69 (15.1%) had staphylococcal VAP, and the remaining 387 (84.9%) had non-staphylococcal VAP. Organophosphorus (OP) poisoning was identified as an independent predictor of staphylococcal VAP (odds ratio: 2.57; 95% CI: 1.4 to 4.73). The median duration of mechanical ventilation before VAP diagnosis was less in the staphylococcal VAP group (4 vs. 5 days; p = 0.004). The staphylococcal group also showed a better in-hospital outcome. Conclusions: OP poisoning was an independent predictor of staphylococcal VAP. Staphylococcal VAP was diagnosed earlier in patients than non-staphylococcal VAP. Screening for nasal carriage for Staphylococcus, especially in patients with OP poisoning at the time of MICU admission, may help guide antibiotic therapy.