Sensitivity and Resistance of the Microorganisms Responsible for Neonatal Sepsis to Antibiotics

Abstract

Background: Sepsis is a major neonatal disease that requires appropriate early treatment. Objectives: The current study aimed to determine the resistance and sensitivity to antibiotics in neonates admitted to the neonatal intensive care unit (NICU) due to sepsis. Methods: In this cross-sectional study, 268 neonates with definitive sepsis (positive blood culture with clinical signs of infection) hospitalized during 2009 - 2019 are investigated. Identification of microorganism and antibiogram test were performed according to the standard microbiological method. Antibiotics susceptibility testing was performed by disk diffusion and microdilution method according to Clinical and Laboratory Standards Institute (CLSI) (2013). A researcher-made questionnaire, including characteristics of neonates and types of microorganisms (Gram-positive or negative) in the neonatal ward, as well as sensitivity and resistance to common microorganisms in neonatal sepsis, was used to collect data. Results: According to the antibiogram results, the microorganism found in NICU showed sensitivity to vancomycin (97%), imipenem (71%), and co-trimoxazole (56%), as well as norfloxacin, cephalotin, and cefazolin (50%). Gram-negative bacteria showed complete sensitivity (100%) to piperacillin, clavulanic acid, colistin, tazobactam, and meropenem and high sensitivity (> 86%) to imipenem, norfloxacin, and ciprofloxacin. There was high resistance to amoxicillin, ampicillin, amikacin, gentamicin, cephalotin, cefotaxime, ceftriaxone, ceftizoxime, cephalexin, and clindamycin. Gram-positive bacteria showed full sensitivity (100%) to doxycycline, piperacillin, and tobramycin and reasonable sensitivity (> 75%) to vancomycin, imipenem, and tetracycline. Azithromycin, ampicillin, gentamicin, cefepime, meropenem, penicillin, erythromycin, oxacillin, and amoxicillin showed resistance in 100% of cases. Conclusions: This study demonstrated high-sensitivity drugs for definitive treatment of neonatal sepsis (i.e., piperacillin, tazobactam, and meropenem for Gram-negatives, and piperacillin, and tobramycin for Gram-positive microorganisms).