ABSTRACT
Diarrhoea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. To investigate the incidence, antimicrobial resistance and genetic relationships of enteropathogenic Escherichia coli (EPEC) in children with diarrhoea, a total of 612 stool specimens were collected in Tehran, Iran, and cultured to isolate strains of EPEC. The disc diffusion method was used to determine the susceptibility of the isolates according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of eae, stx and bfp-A genes was determined by PCR. The genetic relationships between EPEC isolates were determined by pulsed-field gel electrophoresis (PFGE). Out of the 412 strains of E. coli obtained from 612 diarrhoeal stool specimens, 23 (5.6â%) were identified as EPEC, of which seven (30.4â%) were classified as typical strains of EPEC and 16 (69.6â%) were classified as atypical. Out of the 23 EPEC isolates, 69.5â% were resistant to ampicillin, 39.1â% were resistant to tetracycline and cotrimoxazole, 30.4â% were resistant to cefpodoxime, ceftazidime, ceftriaxone and aztreonam, and 26.1â% were resistant to imipenem. The isolates were classified into 21 pulsotypes by PFGE profiles. The present study shows that typical and atypical EPEC isolates displayed considerable heterogeneity in PFGE profiles and EPEC infections were only sporadic in Tehran. Overall 69â% of isolates were resistant to at least one of the antibiotics tested.
Subject(s)
Diarrhea/microbiology , Drug Resistance, Multiple, Bacterial , Enteropathogenic Escherichia coli/drug effects , Escherichia coli Infections/microbiology , Feces/microbiology , Adhesins, Bacterial/genetics , Child , Child, Preschool , DNA, Bacterial/genetics , Enteropathogenic Escherichia coli/genetics , Enteropathogenic Escherichia coli/isolation & purification , Escherichia coli Infections/epidemiology , Escherichia coli Proteins/genetics , Fimbriae Proteins/genetics , Humans , Infant , Microbial Sensitivity Tests , Shiga Toxin/geneticsABSTRACT
Methicillin resistant Staphylococcus aureus (MRSA), particularly strains with type III staphylococcal cassette chromosome mec (SCCmec), represent a serious human pathogen in Tehran, Iran. The disease-causing capability depends on their ability to produce a wide variety of virulent factors. The prevalence of exotoxin genes and multiple-locus variable number of tandem repeats fingerprinting (MLVF) profile among MRSA isolates, from patients in Tehran, was evaluated by PCR and Multiplex-PCR. The MLVF typing of 144 MRSA isolates with type III SCCmec produced 5 different MLVF types. Generally, 97.2% (140/144) of all the isolates were positive for at least one of the tested exotoxin genes. The most prevalent genes were hld, found in 87.5% (126/144) of the isolates followed by lukE-lukD and hla found in 72.9% (105/144) and 70.1% (101/144) of the isolates, respectively. The tst gene, belonging to MLVF types I, IV and V, was found among three of the isolates from blood and wound samples. The sea gene was detected in 58.3% (84/144) of the isolates and the sed and see genes were found in one isolate with MLVF type V. The coexistence of genes was observed in the 87.5% (126/144) of the isolates. The rate of coexistence of hld with lukE-lukD, hla with lukE-lukD and sea with lukE-lukD were 66.7% (96/144), 44.4% (64/144) and 44.4% (64/144), respectively. The present study demonstrated that MRSA strains with type III SCCmec show different MLVF patterns and exotoxin profiles.
