Prevalence of etiological agents and antimicrobial resistance patterns of bacterial meningitis in Nemazee Hospital, Shiraz, Iran

Abstract

Background: Meningitis is a serious inflammation of the meninges, mainly caused by bacteria. Treatment of this life threatening disease should not be delayed; therefore, rapid empirical antibiotic therapy should be immediately started. Antimicrobial therapy based on early Cerebrospinal Fluid (CSF) examination has an important role in limitation of bacterial meningitis. Objectives: The current study aimed to identify the prevalence of etiological agents of bacterial meningitis and their susceptibility patterns against commonly used antibiotics. Patients and Methods: This cross-sectional study was performed within a two-year period 2011-2013 on all patients with suspected meningitis referring to Nemazee Hospital, Shiraz, Iran. Cerebrospinal fluid specimens were collected aseptically, and conventional methods were employed to isolate and identify the bacteria. Antimicrobial susceptibility tests were performed using disk diffusion method according clinical and laboratory standards institute (CLSI) recommendation. Results: Out of 2229 suspected meningitis cases, 255 (11.4%) were detected as positive culture. Most of the isolates were Gram-positive cocci, which 116 (45.5%) were Staphylococcus epidermidis, and 20 (7.8%) identified as Streptococcus spp. Among Gram-negative isolates, Escherichia coli and Acinetobacter spp., each with 19 isolates (5.9%), were predominant. Overall, the most effective antibiotics against Gram-positive cocci were vancomycin (91.5%), chloramphenicol (75.2%), and gentamicin (59.3%), respectively. Gram-negative isolates were mostly susceptible to gentamicin (65.1%), chloramphenicol (42.9%), and ciprofloxacin (39.7%), respectively. Conclusions: Gram-positive cocci, such as (Coagulase-Negative Staphylococci) CoNS and aerobic Gram-negative bacilli, were identified as the common etiologic agents of bacterial meningitis. Since the majority of these isolates was part of the normal flora and considered as opportunistic nosocomial infections, it is required to consider the importance of infection control programs in the healthcare centers.