Role of mechanical ventilation & development of multidrug resistant organisms in hospital acquired pneumonia

Abstract

Background & objectives: Among hospital-acquired infections, pneumonia is considered to be the leading cause of death mainly in patients with mechanical ventilation in intensive care units (ICUs). The present study was undertaken to estimate the occurrence of hospital-acquired pneumonia (HAP) as well as ventilator-associated pneumonia (VAP) along with the effect of different variables and to detect the presence of multi drug resistant (MDR) organisms in the intensive care unit (ICU).

Methods: Of the 328 patients admitted in the ICU during 2001, 241 stayed for > 72 h and 148 were ventilated. The respiratory specimens collected from the cases and controls were sent for cytology, bacterial culture and antimicrobial sensitivity.

Results: The overall rate of HAP was 53.9 per cent, mortality rate was 47.3 per cent and attributable risk of mortality with ventilator was 72.3 per cent. Occurrence of VAP was 81.7 per cent. The rate of acquisition of HAP increased along with the duration of stay in the ICU. Of the total bacterial isolates, 96.2 per cent were obtained from patients on ventilator, an overall preponderance of Gram-negative bacteria, commonest being Pseudomonas spp along with 16.3 per cent polymicrobial infection was found in ICU. A significant number of ICU isolates were MDR in comparison to those from the non-ICU settings.

Interpretation & conclusion: Mechanical ventilation and duration of ICU stay emerged as important risk factors for the development of HAP and VAP. MDR Gram-negative bacilli were the commonest respiratory pathogens responsible for increased mortality in patients with VAP.