Antimicrobial Susceptibility Profile of Bacterial Isolates Among Patients Admitted to the Neurosurgery Intensive Care Unit of a Tertiary Care Hospital: A Cross-Sectional Study.

BACKGROUND AND OBJECTIVES: Patients admitted to the neurosurgery intensive care unit (ICU) are often exposed to mechanical ventilation, invasive procedures, and polypharmacy. Prolonged hospital stays and multiple antibiotics facilitate the development of hospital-acquired infections (HAI). We planned this study to determine the bacteriological profile and antimicrobial susceptibility testing (AST) patterns among neurosurgery ICU patients.

METHODS: This cross-sectional study was conducted from May 2024 to April 2025 at the Kalinga Institute of Medical Sciences (KIMS) in Bhubaneswar, India. This study included adult patients hospitalized in the neurosurgery ICU within the above-mentioned time frame. Specimens like endotracheal tube (ETT) aspirate, blood, urine, and body fluids were collected from the eligible participants and were assessed for the bacteriological profile. Culture media like MacConkey agar, chocolate agar, 5% sheep blood agar, and cysteine lactose electrolyte-deficient (CLED) agar were employed for the growth of pathogenic bacteria. For AST, we used the VITEK 2 system (bioMérieux, Marcy-l'Étoile, France). We used the R software Version 4.4.3 (R Foundation for Statistical Computing, Vienna, Austria) for analysis.

RESULTS: Four hundred twenty-five patients were eligible for the study. The male-to-female ratio was 3:2. The average age of the participants was 58.9 (51.7-72.3) years. The majority of samples were obtained from ETT (308, 72%), followed by blood (79, 19%) and others like urine, pus, etc. (38, 9%), respectively. Most of the pathogens belonged to Enterobacterales (253, 59.5%), followed by non-fermenters (130, 30.6%) and Gram-positive cocci (42, 9.9%), respectively. Klebsiella pneumoniae (162, 38.1%), Acinetobacter baumannii (71, 16.7%), Pseudomonas aeruginosa (50, 11.8%), Escherichia coli (46, 10.8%), and Staphylococcus aureus (32, 7.5%) were the most common pathogenic bacteria. We also discovered some emergent pathogens like Proteus mirabilis (21, 4.9%), Serratia marcescens (7, 1.6%), Elizabethkingia meningoseptica (2, 0.5%), and Morganella morganii (1, 0.2%). Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii isolates demonstrated the highest sensitivity towards tigecycline. Pseudomonas aeruginosa isolates were highly sensitive to cefoperazone-sulbactam and imipenem. Antibiotics like linezolid, vancomycin, tigecycline, daptomycin, and teicoplanin were very effective against Staphylococcus aureus.

CONCLUSION: ETT was the most common sample collected, and most pathogens were from Enterobacterales.The most prevalent pathogens were Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. We also noticed a few cases of emerging pathogens like Elizabethkingia meningoseptica and Morganella morganii. Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae were highly sensitive to tigecycline. Cefoperazone-sulbactam was highly effective against Pseudomonas aeruginosa. Staphylococcus aureus isolates showed maximum sensitivity towards linezolid and vancomycin.