American Journal of Infection Control 40 (2012) 776-7
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American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Brief report
Prevalence of antibiotic resistance among Acinetobacter baumannii isolates from Aleppo, Syria Abdul Rezzak Hamzeh BPharm, PhD a, *, Mona Al Najjar MD, MS b, Maysa Mahfoud MS, PhD a a b
Department of Biochemistry and Microbiology, Faculty of Pharmacy, University of Aleppo, Aleppo, Syria Centralized Clinical Microbiological Laboratory, Albasel and Ibn Rushd hospitals, Aleppo, Syria
Key Words: Carbapenems Colistin Urinary infections Respiratory infections
This study describes and analyzes Acinetobacter baumannii antibiotic susceptibly profile in Aleppo, Syria, thus providing vital information for guiding treatment of A baumannii infections. Two hundred sixty nonrepetitive A baumannii isolates were studied over 3.5 years. Resistance rates are at the higher end of globally reported levels. Newer cephalosporins and b-lactamase-resistant agents are becoming practically ineffective. Better activity is limited to carbapenems and colistin, which elicited the highest susceptibility levels. Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Acinetobacter baumannii is a ubiquitous, aerobic, gram-negative coccobacillus that was once considered nonpathogenic but later emerged as a significant nosocomial pathogen.1 Acinetobacter spp can be an important source of infections in hospitalized patients causing lung infections (pneumonia) and urinary tract infections. This pathogen has been acquiring genetic elements encoding antibiotic resistance, and exposure to antibiotics is effectively selecting for multidrug-resistant strains. Currently, numerous studies around the world indicate that Acinetobacter infections are nearly untreatable.2 Data on prevalence of A baumannii antibiotic resistance in Syria are totally lacking. Therefore, a significant body of information, which is indispensable for practicing health authorities, is missing from the epidemiologic picture. This study aims at presenting and analyzing such data. MATERIALS AND METHODS The centralized clinical microbiologic laboratory in Ibn Rushd and Albasel hospitals is accredited by the Syrian Ministry of Health to serve the metropolitan area of Aleppo (>4 million inhabitants) in northern Syria. Outpatients referred to the facility between January 1, 2008, and June 30, 2011, provided data for this retrospective study. General reasons for referral were mainly urinary tract infections and pneumonia. Clinical (urinary, lower respiratory, * Address correspondence to Abdul Rezzak Hamzeh, BPharm, PhD, Faculty of Pharmacy, University of Aleppo, Aleppo, Syria. E-mail address:
[email protected] (A.R. Hamzeh). Conflicts of interest: None to report.
blood, and wound) specimens from 260 unique patients provided 260 isolates in which A baumannii was identified and tested, and results were interpreted according to the guidelines (including susceptibility breakpoints) of the Clinical and Laboratory Standards Institute.3 Eighty percent of the tested patients were adults (18 years of age), and the remainder were aged between 1 and 17 years. This research was approved by the Ethics Committee of the Faculty of Pharmacy at Aleppo University. A baumannii was identified using standard biochemical reactions and confirmed using an automated system (BD Phoenix Automated Microbiology System for Identification and Susceptibility Testing, Sparks, MD). Antimicrobial susceptibility testing was also performed using BD Phoenix according to manufacturer specifications. Percentages of susceptible isolates in antibiogram (Table 1) were calculated by dividing the number of susceptible isolates (neither intermediately susceptible nor resistant) by the total number of isolates. Comparing susceptibility levels between the beginning of the study period (January 1, 2008, and June 30, 2008) and the end of it (January 1, 2011, and June 30, 2011) was performed using c2 test. Numbers of susceptible and total isolates from start and end of study were arranged in 2 2 contingency tables, and P values were calculated (P < .05 indicated significant differences).
RESULTS The results are presented in the antibiogram in Table 1, describing elevated levels of A baumannii resistance, which pose serious treatment challenges.
0196-6553/$36.00 - Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.ajic.2011.09.019
A.R. Hamzeh et al. / American Journal of Infection Control 40 (2012) 776-7 Table 1 Antibiotic susceptibility shown in antibiogram of Acinetobacter baumannii isolates collected between January 2008 and July 2011 in Aleppo, Syria Acinetobacter baumannii Maximum no. tested ¼ 260 Aztreonam Piperacillin Piperacillin/tazobactam Amoxicillin/clavulanic acid Cefuroxime Cefoxitin Cefotaxime Cefepime Ceftazidime Meropenem Imipenem Nitrofurantoin Ciprofloxacin Gentamicin Amikacin Trimethoprim/sulfamethoxazole Tetracycline Colistin
Percent susceptible 1.5 7.8 13.4 6.8 4.7 5 8.6 15.3 19.4 29.5 35.4 3.6 18.8 17.3 21.7 25.9 31.7 93.1
DISCUSSION Low levels of susceptibility to third- and fourth-generation cephalosporins are notable and range between 19.4% (ceftazidime) and 4.7 % (cefuroxime). This may result from enhanced production of class-C chromosomal b-lactamase (AmpC),4 which is hardly surprising considering the extensive misuse of cephalosporin antibiotics locally. Susceptibility to piperacillin increased significantly from 7.8% to 13.4% by adding b-lactamase inhibitor tazobactam. Unfortunately with
