Incidence, risk stratification, antibiogram of pathogens isolated and clinical outcome of ventilator associated pneumonia

Abstract

Background: The initial empirical therapy of Ventilator Associated Pneumonia (VAP) modified based on the knowledge of local microbiological data is associated with decreased morbidity and mortality. The objective was to find the incidence and risk factors associated with VAP, the implicated pathogens and their susceptibility pattern as well as to assess the final clinical outcome in VAP. Materials and Methods: This was a prospective cohort study of 107 patients taken on ventilatory support for two or more days and those not suffering from pneumonia prior were to be taken on ventilator. The study was done over a period of one year. VAP was diagnosed using clinical pulmonary infection score of >6. The mortality, incidence of VAP, frequency of different pathogens isolated, their antibiotic sensitivity pattern, duration of mechanical ventilation and duration of hospital stay were assessed. Statistical Analysis: Univariate analysis, χ² test and paired t-test. Results: The incidence of VAP was 28.04%. Mortality in VAP group was 46.67%, while in the non-VAP group was 27.28%. High APACHE II score was associated with a high mortality rate as well as increased incidence of VAP. The most common organisms isolated from endotracheal aspirate of patients who developed VAP were Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae and Acinetobacter baumannii. Most strains of Pseudomonas (55.56%) were resistant to commonly used beta-lactam antibiotics known to be effective against Pseudomonas. All strains of Staphylococcus aureus were MRSA and most isolates of K. pneumoniae (85.71%) were extended-spectrum beta-lactamase producing. About 50% isolates of Acinetobacter were resistant to carbapenems. Mortality was highest for infections caused by A. baumannii (83.33%) and K. pneumoniae (71.42%). Conclusions: APACHE II score can be used to stratify the risk of development of VAP and overall risk of mortality. Drug-resistant strains of various organisms are an important cause of VAP in our setting.