Acinetobacter antibiotic resistance and frequency of ESBL-producing strains in ICU patients of Namazi Hospital (2008-2009)

Background: Acinetobacter is a gram-negative pathogenic bacterium and an important cause of nosocomial infections especially in immunocompromised patients in the intensive care units. Reports of multi-drug resistant isolates have increased during the last decade. As a result of extensive use of broad-spectrum antibiotics and high prevalence of ESBL producing bacteria especially in ICU ward, Acinetobacter infection is often difficult to treat. Objective: To determine the antibiotic resistance in Acinetobacter and detecting the prevalence of ESBL producing strains in ICU patients of Namazi Hospital in Shiraz (Iran). Methods: This study was carried our on 147 clinical isolates of Acinetobacter collected from ICU patients at Namazi Hospital during October to December (2008-2009). Antibiotic susceptibility test for isolated strains was performed using disk diffusion method. Also, isolation of ESBL Acinetobacter strains was accomplished using double disk synergy test. Findings: The highest antibiotic resistance among 147 Acinetobacter baumannii strains was found against ciprofloxacin, amikacin, and gentamicin. Regarding the results of initial screening tests, 44% of total samples were demonstrated to be ESBL positive Conclusion: Based on our data, the major reason for emergence of diverse ESBL strains was due to unjustified administration of broad spectrum cephalosporins. Accurate antibiotic susceptibility testing prior to administration of antibacterial agents for patients to reduce the high prevalence of ESBL strains is recommended.