A Study on Bacterial Etiology of Ventilator Associated Pneumonia and its Antimicrobial Pattern

Abstract

Introduction: Ventilator Associated Pneumonia(VAP) remains a major cause of mortality and morbidity among critical ill patients. An imbalance between normal host defenses and the ability of microorganisms to colonize and invade the lower respiratory tract results in hospital acquired pneumonia. Aims and objectives were to isolate and identify bacterial pathogens from VAP and to determine their antibiogram. Material and Methods:A total of 66 Endotracheal aspirates were included in this study. 0.01 ml of sample was inoculated onto Blood agar,Chocolate agar and MacConkey agar and plates were incubated overnight at 37°C for 24 and 48 hours. Bacterial isolates were identified by standard biochemical tests. Antimicrobial sensitivity testing was performed on Muller Hinton Agar by Kirby Bauer disk diffusion and interpreted as per the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: The occurrence of VAP was more common in the age group of 18-30 years (46.51%). Of the total cases 59.09% showed monomicrobial growth and 6.06% showed polymicrobial growth. The predominant gram negative isolate obtained was Klebsiella sp (68.89%) followed by Acinetobacter sp(15.56%) and Pseudomonas aeruginosa (13.33%). Among the Gram negative bacilli, 24.44% were resistant to Piperacillin Tazobactam and 35.56% to Cefoperazone sulbactam and 31.11% isolates were resistant to meropenem.All gram negative isolates were sensitive to Imipenem. Conclusion: Knowledge on incidence of VAP, its etiology and susceptibility patterns is essential to initiate the empirical antibacterial therapy for patients on mechanical ventilation

Bacteriological Profile and antibiogram of isolates from tracheal secretions of patients in an intensive care unit

“…24 Neha Samal et al had a culture positive rate of 85.7% 17 and Masoum Khoshfetrat et al had a culture positive rate of 81.3%. 25 In the present study 26/102 (25.49%) showed polymicrobial growth and 62/102 (60.78%) showed monomicrobial growth which correlates with a study reported by Vamsi C k et al 26 where Gram negative bacilli were the most predominant isolates in our study (84.2%) followed by Gram positive cocci (15.8%) correlating with studies by Neha Samal et al, 17 Chidambaram et al, 7 Khayyam et al 12 and Masoum et al 25 In the present study Klebsiella pneumoniae [ 35/96 (36.46%)] was the predominant Gram negative organism isolated followed by Acinetobacter spp [24/ 27 Malik et al, 28 Deepti C et al, 1 Vimal Shiram Rathod 24 in which Klebsiella pneumoniae was the predominant isolate. But in a study done by Neha Samal et al 17 Acinetobacter baumannii (46%) was the predominant isolate followed by Pseudomonas aeruginosa (17%) and Klebsiella pneumoniae (17%) and Khayyam et al 12 also reported that Acinetobacter spp was the predominant isolate (23.75%) followed by Pseudomonas aeruginosa (21.25%) and Klebsiella pneumoniae (16.25%).…”

“…6 The risk factors for the development of VAP include the patient's endogenous flora, hospital staff, contaminated devices, microaspiration of contaminated oropharyngeal secretions, duration of ventilation, positioning of the patients, enteral feeding, and over sedation. 7 VAP is categorized into early onset VAP (infection occurring during the first five days of the hospital stay) and late onset VAP (infection occurring after five days of the hospital stay). Early onset VAP is often caused by community acquired organisms in contrast to late onset VAP caused by multi drug resistant hospital strains.…”

“…Early onset VAP is often caused by community acquired organisms in contrast to late onset VAP caused by multi drug resistant hospital strains. 7 Early onset VAP is caused by pathogens like Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila, and anaerobic bacteria, and late onset VAP by Pseudomonas aeruginosa, Acinetobacter spp, MRSA, and also by some members of the Enterobacteriaceae family. 8,9 In intubated patients, lower respiratory tract colonization may progress to ventilator associated tracheobronchitis (VAT), which is a precursor to VAP.…”

“…Blood cultures are helpful in conditions like those infected with Streptococcus pneumoniae or Staphylococcus aureus. 7 Several studies also show that the patients admitted to ICUs develop multi-bacterial infections due to their prolonged stay in the hospital. The changing floras also complicate the therapy by developing resistance to multiple antibiotics.…”

Clinical, Bacteriological and Radiological Study of Community Acquired Pneumonia - A Hospital based Study

“…However, the use of the term has been greatly extended to include nonbacterial infection of the lungs that are caused by a wide variety of microorganisms. 2 Pneumonia signifies pulmonary as an inflammatory process. The most significant striking feature of this is consolidation.…”