BACTERIOLOGICAL PROFILE AND ANTIBIOTIC SUSCEPTIBILITY PATTERNS OF BLOODSTREAM INFECTIONS

Bloodstream infections are a significant cause of morbidity and mortality worldwide, with a growing concern over antimicrobial resistance. Understanding the bacteriological profile and antibiotic susceptibility patterns of these infections is essential for effective clinical management and therapy. This study aims to investigate the microorganisms responsible for BSIs and their resistance patterns to commonly used antibiotics. The objective of our study was to present the prevalence of different pathogens isolated from blood cultures, highlighting most common organisms causing BSIs with demographic factors and comorbidities that influence bacteriological profile and to evaluate the susceptibility patterns of isolate organisms to various antibiotics used. This cross-sectional study was conducted at the Microbiology Lab of Railway General Hospital, Rawalpindi, from September to December 2024. A total of 136 blood culture specimens were analyzed using aseptic techniques for sample collection. Blood was inoculated into Brain Heart Infusion broth and incubated under aerobic and anaerobic conditions for up to 7 days. Gram staining was performed to classify isolates as Gram-positive or Gram-negative. Biochemical tests that includes catalase, coagulase, oxidase, API, and triple sugar iron, were used for bacterial identification. Antibiotic susceptibility testing was conducted using the Kirby-Bauer disk diffusion method to determine sensitivity, resistance, and multidrug resistance patterns. Staphylococcus aureus emerged as the most dominant organism with 41.2% occurrence which is gram positive. Escherichia coli was identified to be the second most prevalent organism in our study with 211.8% which is gram negative. While other bacterial strains isolated were Acinetobacter baumannii occurring as the third most frequent organism with 10.3% among bloodstream infected patients, Pseudomonas aeruginosa 7.4 % Klebsiella pneumonia 8.1%, Salmonella typhi 5.8% are gram negative bacteria while gram positive bacteria are Enterococcus faecalis 4.4%, Staphylococcus epidermis 1.5% and Streptococcus spp. 2.2% were bacteria our study patients which were infected with blood stream infection. Antibiotic susceptibility patterns observed among all the seven organisms discovered that isolated of gram positive species both Staphylococcus aureus and Enterococcus faecalis showed high sensitivity rates against linezolid and chloramphenicol (92.3% and 83.3% respectively) and showed high resistance against erythromycin and ampicillin (72.7%, 80% respectively). Similarly, gram negative isolates Escherichia coli showed high resistance against cephalexin 61.5% and great sensitivity against meropenem 91.7%. Klebsiella pneumoniae showed high sensitivity for meropenem 83.3%, and resistant to cephalexin 88.9%. Ciprofloxacin was greatly effective for both Acinetobacter baumannii 84.6% and Pseudomonas aeruginosa 66.7% and Salmonella typhi were sensitive to sulfamethoxazole 71.9% for bloodstream infectious patients. Our study findings shows that the gram positive bacteria Staphylococcus aureus as the most prevalent pathogen among BSIs patients while in gram negative Escherichia coli was highest pathogen along with the antibiotic susceptibility patterns observed emphasizes the requirement to design awareness programs with the purpose to reduce risks of antibiotic resistance.