Prevalence of bacterial infections, antimicrobial sensitivity, and resistance patterns in respiratory samples

Respiratory tract infections (RTIs) are a significant global health concern, particularly with the rise of antimicrobial resistance (AMR). This study aimed to investigate the prevalence of bacterial pathogens, resistance patterns, and gender-specific differences among patients with RTIs admitted to a tertiary-level hospital in South Punjab, Pakistan.

The retrospective study, which lasted from September 2023 to February 2024, included 194 patients with bacterial RTIs. Demographic data, clinical characteristics, and bacterial isolates were analyzed. The antibiotic susceptibility of 194 bacterial isolates was assessed using the disc diffusion method. Bacteria were classified as extensively drug-resistant (XDR), multidrug-resistant (MDR), or pan-drug-resistant (PDR) based on standard criteria. The impact of bacterial resistance on mortality and ICU admissions was examined using multivariate Cox regression analysis.

The study cohort had a mean age of 66.5 ± 10.8 years, with 76.4% being male. ICU admissions were higher among males (25%) than females (9%). Pseudomonas aeruginosa (12.89% in males; 15.46% in females) and Klebsiella pneumoniae (3.61% in males; 9.79% in females) were the most prevalent Gram-negative bacteria, whereas Streptococcus spp. and Moraxella catarrhalis were the most common Gram-positive bacteria. A higher mortality rate was observed among MDR-infected patients (12.22%) compared to those with non-resistant strains (4.89%). Resistance to beta-lactams, fluoroquinolones, and macrolides was particularly pronounced in ICU patients. Gender-specific differences in bacterial prevalence and resistance patterns were noted, with females exhibiting higher rates of P. aeruginosa and MRSA infections.

The study underscores the growing burden of antimicrobial resistance in RTIs, with significant gender-based disparities. The high prevalence of MDR bacteria highlights the urgent need for targeted antibiotic stewardship programs and infection control measures to mitigate the impact of drug-resistant respiratory infections.