Bacteriological Profile and Antibiotic Susceptibility Patterns of Blood Stream Infections

Bloodstream infections (BSIs) significantly contribute to global morbidity and mortality, exacerbated by rising antimicrobial resistance. A thorough understanding of the bacterial profiles and their antibiotic susceptibility is crucial for effective treatment. This study aims to identify the pathogens associated with BSIs, assess their prevalence, and evaluate their antibiotic resistance patterns, considering demographic factors and comorbidities. A cross-sectional study was conducted at the Microbiology Lab of Amjad Naeem Clinic Rawalpindi, from January to June 2024. We analyzed 135 blood culture samples using aseptic techniques. Blood samples were cultured in Brain Heart Infusion (BHI) broth under aerobic and anaerobic conditions for up to 7 days. Isolates were classified using Gram staining and biochemical tests. Antibiotic susceptibility was assessed using the Kirby-Bauer disk diffusion method. Staphylococcus aureus was the most prevalent pathogen, accounting for 41.2%, followed by Escherichia coli at 21.8%. Other notable isolates included Acinetobacter baumannii (10.3%), Pseudomonas aeruginosa (7.4%), and Klebsiella pneumoniae (8.1%). Antibiotic susceptibility revealed that Staphylococcus aureus and Enterococcus faecalis were highly sensitive to linezolid (92.3%) but resistant to erythromycin (72.7%). Escherichia coli showed significant resistance to cephalexin (61.5%) but high sensitivity to meropenem (91.7%). Klebsiella pneumoniae was similarly sensitive to meropenem (83.3%) and resistant to cephalexin (88.9%). Ciprofloxacin was effective against Acinetobacter baumannii (84.6%) and Pseudomonas aeruginosa (66.7%), while Salmonella typhi was sensitive to sulfamethoxazole (71.9%). Our findings indicate that Staphylococcus aureus is the predominant pathogen in BSIs, with Escherichia coli as the leading gram-negative organism. The observed antibiotic susceptibility patterns underscore the need for awareness programs to mitigate antibiotic resistance. Keywords: Bloodstream infection, Antimicrobial susceptibility, CLSI 2023, Rawalpindi