Evaluation of Antimicrobial Susceptibility Patterns of Enterococci Isolated from Patients in Tehran University of Medical Sciences Teaching Hospitals
AbstractThis study investigated the antibacterial resistance among enterococci isolated in Tehran hospitals. A total of 277 Enterococcus faecalis, 123 Enterococcus faecium and 13 isolates of other enterococcal strains were collected from 1 March 2002 to 15 April 2004 from three teaching hospitals of Tehran University of Medical Sciences. The minimum inhibitory concentrations (MIC) of tested antibiotics were determined by agar dilution method. Susceptible and resistant isolates were defined according to the species-related MIC breakpoints of the Clinical and Laboratory Standards Institute (CLSI) guidelines. Sixty- three percent of isolates were resistant to rifampicin (MIC90 64 µg/ml), 44% to ciprofloxacin (MIC90 16≤ µg/ml), 43% to erythromycin (MIC90 512 µg/ml), 32% to cefazolin (MIC90 256≤ µg/ml), 25% to penicillin (MIC90 32 µg/ml), 21% to ampicillin (MIC90 128≤ µg/ml), 8% to vancomycin (MIC90 ≤ 8 µg/ml), and 8% to teicoplanin (MIC90 16≤ µg/ml). All of the vancomycin-resistant strains carried the vanA phenotype and genotype. High level resistance to gentamicin and streptomycin were found in 52% and 83% of the isolates, respectively. The results indicated that a significant percentage of isolates are resistance to different antibiotics, pointing out the need for control strategies to avoid dissemination of resistant isolates and for continuous surveillance for the detection of emerging resistance traits.
Cetinkaya Y, Falk P, Mayhall CG. Vancomycin-resistant enterococci. Clin Microbiol Rev 2000; 13(4): 686-707.
Schouten MA, Hoogkamp-Korstanje JA, Meis JF, Voss A; European VRE Study Group. Prevalence of vancomycinresistant enterococci in Europe. Eur J Clin Microbiol Infect Dis 2000; 19(11): 816-22.
Fatholahzadeh F, Hashemi FB, Emaneini M, Aligholi M, Nakhjavani FA, Kazemi B. Detection of Vancomycin resistant Enterococci (VRE) isolated from Urinary Tract Infections (UTI) in Tehran, Iran. Daru 2006; 14(3): 141-5.
Feizabadi MM, Asadi S, Aliahmadi A, Parvin M, Parastan R, Shayegh M, et al. Drug resistant patterns of enterococci recovered from patients in Tehran during 2000-2003. Int J Antimicrob Agents 2004; 24(5): 521-2.
Udo EE, Al-Sweih N, Phillips OA, Chugh TD. Species prevalence and antibacterial resistance of enterococci isolated in Kuwait hospitals. J Med Microbiol 2003; 52(Pt 2): 163-8.
Murray BE. The life and times of the Enterococcus. Clin Microbiol Rev 1990; 3(1): 46-65.
Reinert RR, Conrads G, Schlaeger JJ, Werner G, Witte W, Lütticken R,et al. Survey of antibiotic resistance among enterococci in North Rhine-Westphalia, Germany. J Clin Microbiol 1999; 37(5): 1638-41.
Forbes BA, Sahm DF, Weisfeld A. Bailey and Scott's Diagnostic Microbiology. 10th ed. St. Louis, Missouri; Mosby; 1998.
National Committee for Clinical Laboratory Standards. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. Approved Standard M7-A4. National Committee for Clinical Laboratory Standards (NCCLS): Wayne, PA, USA, 2004.
Dutka-Malen S, Evers S, Courvalin P. Detection of glycopeptide resistance genotypes and identification to the species level of clinically relevant enterococci by PCR. J Clin Microbiol 1995; 33(1): 24-7.
Low DE, Keller N, Barth A, Jones RN. Clinical prevalence, antimicrobial susceptibility, and geographic resistancepatterns of enterococci: results from the SENTRY Antimicrobial Surveillance Program, 1997-1999. Clin Infect Dis 2001; 32 Suppl 2: S133-45.
Edmond MB, Ober JF, Dawson JD, Weinbaum DL, Wenzel RP. Vancomycin-resistant enterococcal bacteremia: natural history and attributable mortality. Clin Infect Dis 1996; 23(6): 1234-9.
Jones RN, Sader HS, Erwin ME, Anderson SC. Emergingmultiply resistant enterococci among clinical isolates. I. Prevalence data from 97 medical center surveillance study in the United States. Enterococcus Study Group. Diagn Microbiol Infect Dis 1995; 21(2): 85-93.
French GL. Enterococci and vancomycin resistance. Clin Infect Dis 1998; 27 Suppl 1: S75-83.
Zouain MG, Araj GF. Antimicrobial resistance of Enterococci in Lebanon. Int J Antimicrob Agents 2001; 17(3): 209-13.
Udo EE, Al-Sweih N, John P, Chugh TD. Antibiotic resistance of enterococci isolated at a teaching hospital in Kuwait. Diagn Microbiol Infect Dis 2002; 43(3): 233-8.
Kaçmaz B, Aksoy A. Antimicrobial resistance of enterococci in Turkey. Int J Antimicrob Agents 2005; 25(6): 535-8.
Titze-de-Almeida R, Rollo Filho M, Nogueira CA, Rodrigues IP, Eudes Filho J, Nascimento RS, et al. Molecular epidemiology and antimicrobial susceptibility of Enterococci recovered from Brazilian intensive care units. Braz JInfect Dis 2004; 8(3): 197-205.
Chaudhary U, Shamma M, Yadav A. Antimicrobial susceptibility patterns of common and unusual enterococcus species isolated from clinical specimens. J Infect Dis Antimicrob Agents 2007; 24: 55-62.
Hryniewicz W, Zareba T, Kawalec M. Susceptibility patterns of Enterococcus spp. isolated in Poland during 1996. Int J Antimicrob Agents 1998; 10(4): 303-7.
Udo EE, Al-Sweih N, John P, Jacob LE, Mohanakrishnan S. Characterization of high-level aminoglycoside-resistant enterococci in Kuwait hospitals. Microb Drug Resist 2004; 10(2): 139-45.
Feizabadi MM, Maleknejad P, Asgharzadeh A, Asadi S, Shokrzadeh L, Sayadi S. Prevalence of aminoglycosidemodifying enzymes genes among isolates of Enterococcus faecalis and Enterococcus faecium in Iran. Microb Drug Resist 2006; 12(4): 265-8.
del Campo R, Tenorio C, Rubio C, Castillo J, Torres C, Gómez-Lus R. Aminoglycoside-modifying enzymes in high-level streptomycin and gentamicin resistant Enterococcus spp. in Spain. Int J Antimicrob Agents 2000; 15(3): 221-6.
Emaneini M, Hashemi FB, Aligholi M, Fatholahzadeh B, Kazemi B, Sadeghi F. Detection of vanB genotype enterococci in Iran. Int J Antimicrob Agents 2005; 26(1): 98-9.