Bacterial Profile and Antimicrobial Susceptibility Patterns of Neonatal Infections among Neonates Admitted to the Neonatal Intensive Care Unit of Tobruk Medical Centre

Abstract

Neonatal infections are significant causes of morbidity, mortality, and prolonged hospitalisation among newborns. Effective management requires optimal antimicrobial therapy guided by epidemiological studies of bacterial susceptibility. This study aimed to identify the most common bacteria implicated in neonatal infections in the neonatal intensive care unit (NICU) at Tobruk Medical Centre and their antibiotic susceptibility patterns, which, in turn, can assist in selecting effective treatment. This study included 311 culture records from all newborns admitted to the NICU at Tobruk Medical Centre between January 2019 and December 2020. Different types of samples were analysed in the microbiology laboratory, including blood, urine, cerebrospinal fluid (CSF), umbilical cord, and other samples. All samples were examined for microbiological confirmation and for patterns of antibiotic susceptibility by the disc diffusion method. In total, 55 (17.7%) of the specimens showed positive growth, including 50 (16.1%) clinically relevant positive cultures. Blood cultures showed the highest number of clinically relevant positive results (23/78; 29.5%), followed by umbilical cord (11/12; 91.7%). Bacteriological examination showed that the most frequently isolated microorganisms were Klebsiella pneumoniae (17; 34.0%), followed by Staphylococcus aureus (16; 32.0%), Escherichia coli (9; 18.0%), Staphylococcus epidermidis (5; 10.0%), and Enterobacteriaceae (3; 6.0%). Antibiotic susceptibility testing was performed for the major bacterial isolates. Among blood isolates, K. pneumoniae showed sensitivity to meropenem (100%), imipenem (50%), and ceftriaxone (25%), while E. coli showed greater sensitivity to imipenem (75%), amikacin (50%), and doxycycline (100%). S. aureus showed sensitivity to meropenem (100%) and vancomycin (25%), whereas S. epidermidis showed sensitivity to cefixime (100%) and vancomycin (33.3%). For urine isolates, K. pneumoniae showed 100% sensitivity to ciprofloxacin and 50% to ceftriaxone and cefotaxime, while E. coli showed limited sensitivity, with 33.3% sensitivity to colistin. In addition, S. aureus showed sensitivity to amikacin (100%). Eye-discharge isolates demonstrated 100% sensitivity of K. pneumoniae to neomycin and levofloxacin, while S. aureus showed 100% sensitivity to colistin. Among umbilical isolates, Klebsiella spp. showed 66.7% sensitivity to imipenem, while S. aureus demonstrated sensitivity to imipenem (75%), tetracycline (100%), clindamycin (100%), and gentamicin (100%). Generally, numerous isolates showed complete resistance to commonly used antibiotics, including amoxicillin/clavulanate, ampicillin, and several cephalosporins. The findings indicate that Klebsiella pneumoniae and Staphylococcus aureus were the most common bacteria in the NICU during 2019–2020. The marked resistance to commonly used antibiotics highlights an important challenge to management, especially in the neonatal critical care unit in Tobruk. Furthermore, the bacteria that cause newborn infections and their antibiotic susceptibility patterns can change over time and between hospitals. Continuous monitoring of microbial epidemiology and susceptibility profiles is therefore required to guide empirical treatment.