Molecular Investigation of Extended-Spectrum β-Lactamase and Patterns of Antibiotic Resistance in Enterobacter cloacae Isolates from Teaching Hospitals in Kermanshah, Iran

Abstract

Introduction: Enterobacter cloacae are responsible for a variety of hospital acquired infections including sepsis and Urinary Tract Infection (UTI). High emergence rate of Extended Spectrum β-Lactam (ESBL) resistant bacteria has led to increased rates of mortality, therapeutic failure and healthcare expenses. Identification of Cefotaximase-Munich (CTX-M), Temoneira (TEM), and Sulphydrylvariable (SHV) genes can help in determining the epidemiology, and thereby aid in development of anti-microbial therapy. Aim: To determine molecular frequency of ESBL in E.cloacae isolates obtained from Teaching Hospitals of Kermanshah, Iran. Materials and Methods: The descriptive cross-sectional study was conducted from January 2017 to November 2017, and 93 E.cloacae isolates were collected. All isolates were identified by standard microbiological and biochemical methods including Triple Sugar Iron (TSI) and Indole, Methyl red, Voges-Proskauer, Citrate (IMViC) test. After identifying the resistance pattern of such isolates via Disc diffusion test (DDST), isolates were evaluated for ESBLs using combination disc phenotypic method. Frequency of CTX-M, TEM, and SHV genes was investigated by Polymerase Chain Reaction (PCR). Chi-square and Fisher’stests were used for statistical analysis. The p-values <0.05 were considered statistically significant. Results: Maximum number of isolates were resistant to Amoxicillin-Clavulanic acid (97.8%), followed by Tetracycline and Ceftazidime (60.2%), and Colistin had the highest sensitivity (100%). Among them, 55 (59.1%) isolates had an ESBL phenotype and 65 (69.9%) of them were Multi-Drug Resistant (MDR). The frequency of CTX-M, TEM, and SHV genes was 26 (47.3%), 12 (21.8%) and 3 (5.5%), respectively. CTX-M was found to be resistance to Cefotaxime (p-value=0.038), Ceftazidime (p-value=0.046), and Imipenem (p-value=0.016), and TEM gene was resistant to Ceftazidime (p-value=0.024) and Chloramphenicol (p-value=0.019). Conclusion: Increasing antibiotic-resistant in E. cloacae isolates is a serious concern for public health that warrants judicious use of antibiotics, and rapid identification of ESBL positive isolates.

Keywords

• antimicrobial therapy
• β-lactams
• drug resistance
• polymerase chain reaction
• urinary tract infection