ABSTRACT
The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin A) and intll (encoding a class 1 integrase) in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI) during September 2009 to September 2010 and screened for hlyD and intll genes by polymerase chain reaction (PCR). Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D) and that uropathogenic E. coli (UPEC) isolates mainly belong to groups B2 (54%) and D (34%) whereas group A (44%) and D (26%) are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p < 0.05). intll gene was more frequently expressed in UPEC (24%) in comparison with commensal E. coli isolates (12%). Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed regarding their phylogenetic groups, presence of class 1 integron and hlyD gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coli isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC.
Subject(s)
Child , Child, Preschool , Female , Humans , Male , Escherichia coli Infections/microbiology , Escherichia coli/classification , Feces/microbiology , Genetic Variation , Phylogeny , Urinary Tract Infections/microbiology , Urine/microbiology , Anti-Bacterial Agents/pharmacology , Cluster Analysis , Drug Resistance, Bacterial , Escherichia coli Proteins/genetics , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli/isolation & purification , Genotype , Hemolysin Proteins/genetics , Integrases/genetics , Membrane Transport Proteins/genetics , Polymerase Chain Reaction , Sequence Analysis, DNAABSTRACT
Aims: The aim of this study was to determine the prevalence of methicillin resistant S. aureus (MRSA), vancomycin resistant or vancomycin intermediate resistant S. aurues (aureus) (VRSA/VISA) among clinical isolates. Study Design: S.aureus isolates used in this study were randomly collected from in-patient and outpatient of several hospitals of 7 cities in Iran (Tehran, Shiraz, Zahedan, Tabriz, Sannandaj, Sari, and Ahvaz) during 2006-2008. Methodology: Antibiotic susceptibility of 250 strains of Staphylococcus aureus isolated from Iranian hospitals were determined by disk diffusion method. Minimum inhibitory concentration (MICs) were determined for oxacillin and vancomycin by E-test. PCRs were used by specific primers (PCR used specific primers) for detection of mecA, vanA, vanB genes. Results: The percentage of resistance by disk diffusion method was as below: methicillin 46%, vancomycin 0%, penicillin 86%, erythromycin 42%, ciprofloxacin 29%, gentamicin 39% and clindamycin 33%. E-test MIC method showed that 43% isolates were resistant to methicillin and 4% isolates were VISA (≤ 8μg/ml). The prevalence of resistance genes in the clinical isolates were: mecA 44%, vanA 0%, vanB 0%. Conclusion: This study revealed that clinical isolates have rather high resistance to methicillin, erythromycin, gentamicin, penicillin and clindamycin We did not observe resistance to vancomycin. In order to avoid a possible outbreak involving VISA), vancomycin should be used carefully as a drug for treatment of S. aureus infections.
ABSTRACT
INTRODUCTION: Pseudomonas aeruginosa (P. aeruginosa) is one of the primary opportunistic pathogens responsible for nosocomial infections. Aminoglycosides are an import ant component of antipseudomonal chemotherapy. The inactivation of drugs by modifying enzymes is the most common mechanism of aminoglycoside resistance. OBJECTIVES: The inactivation of aminoglycosides by modifying enzymes is the primary resistance mechanism employed by P. aeruginosa. The aim of the present study was to investigate the occurrence of aminoglycoside resistance and the prevalence of four import ant modifying enzyme genes (aac (6')-I, aac (6')-II, ant (2")-I, aph (3')-VI) in P. aeruginosa in Iran. METHODS: A total of 250 clinical isolates of P. aeruginosa were collected from several hospitals in seven cities in Iran. Antimicrobial susceptibility tests (using the disk diffusion method and E-tests) were performed for all 250 isolates. In addition, all isolates were screened for the presence of modifying enzyme genes by polymerase chain reaction. RESULTS: The resistance rates, as determined by the disk diffusion method, were as follows: gentamicin 43 percent, tobramycin 38 percent, and amikacin 24 percent. Of the genes examined, aac (6')-II (36 percent) was the most frequently identified gene in phenotypic resist ant isolates, followed by ant (2")-I, aph (3')-VI, and aac (6')-I. CONCLUSIONS: Aminoglycoside resistance in P. aeruginosa remains a signific ant problem in Iran. Therefore, there is considerable local surveillance of aminoglycoside resistance.