Incidence of Biofilm Formation in ET Tube and Correlation with Occurrence of VAP in a Tertiary Care ICU

Abstract

Introduction: VAP is one of the most frequent hospital-acquired infections occurring in mechanically ventilated patients and is associated with increased mortality, morbidity, and health-related costs. Bacterial biofilm has been observed universally on the surface of endotracheal tubes in mechanically ventilated patients. Some data show a good concordance between bacterial colonization of the airway and microbial findings in the biofilm. Even the same microorganisms causing VAP could be found in the ETT biofilm leading to the potential implication of biofilm in the genesis of VAP. Aims and Objectives: The objective was to investigate the involvement of ETT biofilm in VAP pathogenesis. Materials and Methods: This observational descriptive study was conducted in Department of Pulmonary Medicine, D.Y Patil Hospital, Nerul, Navi Mumbai. Approval of Institutional Ethics Committee was taken before start of the study. A written signed informed consent was taken prior to enrolling the subjects in the study. Patients requiring mechanical ventilation for at least 24 hours were included in the study. The following data were recorded in a standardized form: age and sex of the patient, cause of mechanical ventilation, duration of ventilation, manoeuvres to prevent VAP, the occurrence or not of nosocomial pneumonia, together with data of pathogen isolated in respiratory samples and/or ETT biofilm, antibiotic therapy and sensitivity patterns. Statistical Method: Descriptive and analytical statistics was done. The data was analyzed using statistical software (IBM SPSS V20.1, IBM Corporation, Armonk, NY, USA). The results are expressed as mean ± standard deviation and proportions. Categorical variables were compared using chi-square tests. The statistical significance was determined at p<0.05.Results: A total of 55 subjects fulfilling the inclusion criteria were participated in the study. The mean age of the study population was 46.56 19.79 with a range of 18 to 87 years. There were 23 (41.8%) males and 32 (58.2%) female’s subjects in the study population. The patients were intubated for mainly three reasons – AHF, ARF and CVA. The diagnosis of the ventilated patients was as follows – pneumonia (25.4%), ARDS (18.2%), cerebral stroke (16.4%), septic shock (16.4%), hemorrhagic shock (9.1%), cardiac arrest (7.3%), cardiopulmonary failure (5.4%) and interstitial lung disease (1.8%). The mean duration of intubation was 10.23 1.55, ICU days was 13.45 1.34 and hospital days was 19.72 2.84. Out of the 55 ventilated patients, 9 (16.3%) patients developed VAP. Biofilm was found positive in 30 (54.5%) patients. In the present study the three most common organisms found in ET tube were Acinetobacter (23.6%), klebsiella (18.2%), E.Coli (7.3%). The other organisms found were Pseudomonas (7.3%), Candida Albicans (3.6%) and staphylococcus (1.8%). The incidence of VAP development in biofilm positive cases was 30%. Conclusion: Biofilms are highly organized microbial communities which in vivo play an important part in evading the defence mechanism and obstinate the antimicrobial therapy. The precise link between biofilm productions in mechanically ventilated patients is still obscure apart from some limited studies which have described role of a specific pathogen or virulence factor. The present study, thus, showed that majority of the pathogens isolated possessed capability to produce biofilm.