Declining Trend in Antimicrobial Sensitivity in Respiratory Tract Bacterial Pathogens against Commonly Used Drugs at a Tertiary Care Hospital.

Objectives: Antimicrobial resistance (AMR) is a major health issue. To determine trends in bacterial organisms in respiratory tract infections (RTIs) and their antibiotic sensitivity at a tertiary care center in India, we performed this study.

Methods: Successive samples received from January 2017 to December 2021 from the respiratory tract (sputum, endotracheal secretion, and bronchoalveolar lavage) from intensive care units and medical inpatients were processed for bacterial growth. The identification of isolates and antibiotic sensitivity patterns was performed using an automated VITEK-2 system. Descriptive statistics are reported.

Results: We received 7,204 respiratory samples. Significant bacterial growth was in 3,000 (41.6%), and 2,992 (41.5%) were gram-negative. was the most prevalent, followed by , , , and . Increasing secular trends were observed for and and declining trends for and ( < 0.05). Antimicrobial sensitivity patterns showed that , , , and had a high sensitivity with colistin and polymyxin (99-100%). Moderate sensitivity was observed with carbapenems ( 47.5%, 62.0%, 76.5%, 72.3%, 66.7%) and tigecycline ( 50.4%, 68.0%, 81.1%, 66.6%, 0%). Aminoglycosides had <50% sensitivity for various organisms, and <25% sensitivity was observed with third-generation cephalosporins and quinolones. Trend analysis showed persistent sensitivity of various pathogenic bacteria to colistin and polymyxin and declining pharmacological sensitivity in (carbapenems and tigecycline), (carbapenems, quinolones, and tigecycline), (carbapenems, quinolones, aminoglycosides, and tigecycline), and (carbapenems and aminoglycosides) species ( < 0.05).

Conclusion: Common respiratory tract gram-negative bacterial pathogens at a tertiary care hospital are K. pneumoniae, P. aeruginosa, A. baumannii, and E. coli. All these bacteria demonstrate high sensitivity only with colistin and polymyxin. Significant AMR is observed to carbapenems, tigecycline, aminoglycosides, and third-generation cephalosporins. Secular trends show declining antimicrobial sensitivity among various bacterial pathogens.