جستجوی مقالات مرتبط با کلیدواژه « Shiga toxin-producing E. coli » در نشریات گروه « پزشکی »

Escherichia coli O157: H7 is one of the most important causes of hemorrhagic colitis, and hemolytic uremic syndrome. The present study aimed to isolate E. coli O157: H7 from foods and patients with hemorrhagic colitis, and identify Shiga toxin genes, phylogenetic comparison, and antibiotic resistance of the isolates.

In total 400 samples, including patients stool and food were taken in Isfahan-Iran province. Pheno- typic tests and PCR were performed to identify Shiga toxin-producing E. coli. The isolated strains were compared phyloge- netically by PFGE. Agar disk diffusion was performed to identify the antibiotic resistance of the isolates.

Totally, 5 isolates of fecal samples were E. coli O157, but only 2 isolates carried H7 gene. Also, 9 isolates of E. coli O157 were isolated from food samples that 3 isolates were E. coli O157: H7. The isolates carried stx1, stx2, hlyA and eaeA genes. Also, E. coli non-O157: H7 identified from samples that contained stx1, stx2, hlyA genes. The highest susceptibility to imipenem and the highest resistance to ampicillin and ciprofloxacin were observed. There was a similarity of 100% between the E. coli O157: H7 strains isolated from patients and raw milk and minced beef samples.

Serotypes other than the O157 of E. coli are more prevalent in patients and food. The E. coli O157: H7 isolates from patients had 100% genetic similarity with minced meat and cow milk isolates, which indicates cattle are the most im- portant reservoir of this bacterium in Iran.

 Shiga toxin-producing strains have been considered remarkable diarrheagenic agents and foodborne pathogens. Several studies have mentioned the role of some Shiga toxin-producing Escherichia coli (STEC) strains in diarrhea and dysentery in calves. Enteropathogenic E. coli (EPEC) have also been isolated from diarrheic calves. Generally, the culture and antibiogram results obtained from fecal samples are used to select antibiotics to treat calf diarrhea. However, the value of such a sampling method has not been evaluated yet.

 This study aimed to evaluate the clinical utility of fecal sample cultures for isolating STEC and EPEC in calf diarrhea by comparing them with small intestine samples.

 The small intestine and fecal samples were simultaneously collected from 35 diarrheic calves. Small intestine samples were collected under the ultrasonographic guide. A total of 70 confirmed E. coli isolates were screened by the multiplex polymerase chain reaction to detect genes encoding Shiga toxin1 (stx1), Shiga toxin2 (stx2), intimin (eae), and hemolysin (E-hly). We also compared the presence of class 1 and 2 integrons and antimicrobial resistance properties in the STEC and EPEC isolates recovered from the small intestine and fecal samples. Finally, the presence of important STEC/EPEC serogroups, including O26, O103, O111, O113, O145, and O157 in isolates from both samples, was determined as well.

 STEC strains were detected in 25.7%, and 20% of E. coli isolates obtained from the small intestine and fecal samples, respectively. The stx1 was the sole Shiga toxin subtype detected among STEC in intestinal and fecal isolates. EPEC was detected only in one and two E. coli isolates from the small intestine and fecal samples, respectively.

 A numerically higher prevalence of STEC was observed in the small intestine compared to fecal samples; there was no significant difference in the frequencies of STEC and EPEC isolates between the small intestine and fecal samples. The results indicated that the fecal sample, as a non-invasive and practical method, could be used for isolating STEC and EPEC in calf diarrhea. The antibiogram showed the presence of a high degree of multi-drug resistance among the isolates.

Aim: The present study was conducted to detect the occurrence, serogroups, virulence genes and phylogenetic relationship of shiga toxin-producing Escherichia coli (STEC) in human, clave and goat in Kerman (southeast of Iran).
STEC have emerged as the important foodborne zoonotic pathogens causing human gastrointestinal disease and confirming the risk to public health.
A total of 671 fecal samples were collected from diarrheic patients (n=395) and healthy calves (n=156) and goats (n=120) and screened for the presence of stx gene. Furthermore, the prevalence of stx1 and stx2 variants, serotypes (O157, O145, O103, O26, O111, O91, O128, and O45), phylogenetic groups and the presence of ehxA, eae, hylA, iha and saa virulence genes were studied.
Prevalence of STEC in human diarrheic isolates was 1.3% (5 isolates), in claves was 26.3% (41 isolates) and in goats was 27.5% (33 isolates). stx1 gene was the most prevalent variant and detected in 75 isolates. Furthermore, stx1c was the most predominant stx subtype, found in 56 isolates. The ehxA identified in 36 (45.6%) isolates, followed by iha 5 (6.3%), eaeA 4 (5.1%), hlyA 2 (2.5%) and saa 2 (2.5%). Most of the isolates belonged to phylogroup B1. Only two O26 and one O91 isolates were detected in our study.
Our results show that STEC strains were widespread among healthy domestic animals in the southeast of Iran

BackgroundResistant Shiga toxigenic Escherichia coli (STEC), is the most prevalent source of diarrhea in pediatrics. This study was conducted to investigate the antimicrobial resistance properties of STEC strains of diabetic and non-diabetic pediatrics with diarrhea.
This was a case-control study conducted from December 2014 to September 2015 in an educational hospital, Jiroft city, Iran. Diarrheic stool samples were collected from diabetic (n= 385) and non-diabetic (n= 300) pediatrics. The samples were cultured and the STEC strains were tested by disk diffusion and polymerase chain reaction (PCR) amplification were applied for detecting antibiotic resistance genes.
ResultsSampling was performed from 685 patients (51.8% male). Total prevalence of STEC strains in diabetic and non-diabetic pediatrics were 6.5% and 3.0%, respectively (P = 0.007). Prevalence of the gens that encode resistance against ampicillin (CITM), fluoroquinolone (qnr), trimethoprim (dfrA1), tetracycline (tetA), gentamicin [aac(3)-IV] and sulfonamide (sul1) were 97.1%, 64.7%, 61.8%, 58.8%, 58.3% and 52.9%, respectively. Non-diabetic pediatrics harbored the lower prevalence of antibiotic resistance genes (P = 0.034).
ConclusionHigh numbers of STEC, especially O157 strains, showed a multidrug-resistance against ampicillin, ciprofloxacin, gentamycin, sulfamethoxazole, and tetracycline. CITM, qnr, dfrA1, tetA, [aac(3)-IV] and sul1 antibiotic resistance genes were identified in the STEC strains of diarrheic samples of diabetic and non-diabetic pediatric patients.

The objectives of this study were to evaluate the antibiotic resistance profiles, biofilm formation, presence of antigen 43 (Ag43) gene, and transfer of antibiotic resistance phenotype among non-O157 Shiga toxin producing Escherichia coli (STEC).
From October 2014 to November 2015 a total of 276 stool samples were collected from healthy calves, goats and 395 patients with the sign of nonbloody diarrhea and screened for presence of stx and serotype O157 genes by polymerase chain reaction (PCR) technique. Susceptibility to 14 antibiotics was determined as per CLSI guideline. Presence of Ag43 and intimin (eaeA) genes were detected by PCR. Biofilm formation was measured by microtiter plate method. Conjugation was carried out by membrane filter technique.
We isolated 74 (93.6%) non-O157 STEC strains from 41 calves, 33 goats and 5 (6.3%) patients’ stools, however, no O157 serotype was detected in our study. Resistance was observed most commonly to tobramycin (66.2%), kanamycin (48.6%), and amikacin (29.7%) and less frequently to ciprofloxacin (4.1%), amoxicillin-clavulanic acid (5.4%), and ceftriaxone (9.5%) in isolates recovered from calves and goats fecal samples, whereas, all human isolates were sensitive to ceftazidime, ciprofloxacin, tobramycin and imipenem, respectively. Furthermore, Ag43 was detected in 60 STEC isolated from animals and 5 human origins (no eaeA gene was found in this study). Biofilm formation from Ag43 and Ag43- colonies showed 20 isolates with strong biofilm activities. Cefotaxime resistance phenotype was transferred to E. coli ATCC 25922.1 (Nalr) by conjugation at a frequency of 1.6×10-4.
From the above results we concluded that, human infections with non-O157 STEC were significantly low in Kerman. Ag43 was insignificant with biofilm quantity in most cases.