Current antimicrobial susceptibility profile of Gram-negative organisms isolated from blood culture specimens of a tertiary care hospital, Balochistan

Objective: To assess the prevalence of Gram-negative bacteria and their resistance patterns in hospitalized patients, essential for targeted interventions and improving BSI patient care. Material and Methods: This laboratory-based cross-sectional study was conducted at the Microbiology Department, Combined Military Hospital, Quetta, over two years (June 2021-July 2023). Of 12,026 blood cultures processed, 1,790 (14.8%) were flagged positive. Specimens were dealt as per standard microbiological techniques. Antibiotic susceptibility was tested via the Kirby Bauer disc diffusion method, with quality control ensured using reference strains and CLSI 2021-23 guidelines. Results: Only 908 positive cultures showed growth of significant pathogens including 806 (88.76%) were Gram-negative isolates: oxidase-negative rods (28.1%), oxidase-positive rods (23.4%), and Typhoidal Salmonella (48.5%). All isolates were 100% resistant to ampicillin, with high resistance to amoxicillin-clavulanic acid (91.6%), ceftriaxone (77.8%), and ciprofloxacin (73%). Resistance to imipenem (52.6%), gentamicin (48.2%), and amikacin (39.4%) was lower, with no resistance to colistin. Oxidase-positive isolates had lower resistance, though Burkholderia cepacia was resistant to polymyxins. In Salmonella, 3.6% were resistant to azithromycin, but all were sensitive to meropenem. Conclusion: Bloodstream infections are common in developing countries and Blood culture is essential for diagnosis. Increasing antimicrobial resistance can be curtail by encouraging public education along strict infection control practices are key to managing this issue. Keywords: Blood stream infections, Blood cultures, Gram negative rods, Antimicrobial resistance