Study of Resistance Pattern in Mucoid and Non Mucoid Isolates of Pseudomonas aeruginosa from Lower Respiratory Tract Specimens in a Tertiary Care Centre of Western U.P.

Abstract

Introduction: Respiratory tract infections are a major cause of ambulatory visits to the family practitioners .However, increase in antibiotic resistant strains of bacteria has complicated the use of empiric therapy of this common human disease. Among the Gram negative bacilli which are the commonest pathogen of LRTI, Pseudomonas aeruginosa is the most challenging, because of its high rate of resistance to antimicrobial agent. Objectives: To obtain a comprehensive insight into the different resistant types: Multi drug resistant, Extensively drug resistant, Carbapenem Resistant, and MBL producing Pseudomonas aeruginosa isolated from lower respiratory tract specimens and antibiotic susceptibility differences between its mucoid and non mucoid colony types based on colony morphology. Material and Methods: A total of 926 lower respiratory tract samples consisting of sputum,pleural fluid,endotracheal aspirates,Bronchoalveolar lavage from patients of all age and sex , suggestive of LRTI were included. Following Direct Gram staining and culture, the organisms were isolated and Pseudomonas aeruginosa among them were identified by standard biochemical tests. The different types of colony morphologies of Pseudomonas aeruginosa and the antimicrobial susceptibility differences amongst the different colony types were statistically analysed. Results: A total 175 (18.8%) Pseudomonas were isolated from different Lower respiratory specimen Out of these, only 103 Pseudomonas aeruginosa were found to be clinically significant with 84.5% non mucoid and 11.4% mucoid colony types. The mucoid colony types showed high resistance to Cefepime (35%), followed by Ceftazidime (20%) and Amikacin (15%). Conclusion: The high rate of MDR and XDR Pseudomonas aeruginosa also resistant to Carbapenems from this region reveals a frightening scenario.As molecular methods are not available in majority of resource constrained laboratories of India, the phenotypic methods should be regularly performed to detect the various beta-lactamases, besides strict infection control practices.