Bacteriological Profile and Antibiotic Susceptibility Pattern of Bloodstream Infections in Hospitalized Patients: A Cross-Sectional Study

Abstract

Background: Bloodstream infections (BSIs) are among the most serious nosocomial infections, often leading to sepsis, prolonged hospital stays, and increased mortality. Identification of causative organisms and knowledge of local antimicrobial susceptibility patterns are essential for guiding empirical therapy.

Objective: To identify bacterial pathogens causing bloodstream infections in hospitalized patients and evaluate their antibiotic resistance profiles using Clinical and Laboratory Standards Institute (CLSI) guidelines.

Methods: This cross-sectional study included 310 blood culture samples collected from suspected septicemic patients over a period of six months. Culture and sensitivity were performed using standard microbiological techniques. Antibiotic susceptibility testing was done using the Kirby-Bauer disk diffusion method and interpreted according to CLSI guidelines. Statistical analysis included descriptive statistics and chi-square test for categorical variables.

Results: Out of 310 blood cultures, 106 (34.2%) were positive. Gram-negative bacilli accounted for 57.5% of isolates, with Klebsiella pneumoniae (25.4%) and Escherichia coli (19.8%) being predominant. Among gram-positive cocci, Staphylococcus aureus was most common (26.4%), with 42.9% being MRSA. High resistance was noted to third-generation cephalosporins and fluoroquinolones. Amikacin, carbapenems, and vancomycin were the most effective agents. Multidrug resistance was significantly associated with prior ICU admission (p = 0.01).

Conclusion: Bloodstream infections in hospitalized patients are predominantly caused by gram-negative bacteria. Rising resistance to empirical antibiotics highlights the need for regular surveillance and adherence to antimicrobial stewardship practices.

Keywords: Bloodstream infections, antibiotic resistance, gram-negative bacilli, MRSA,