OBJECTIVETo type and group the Shiga-toxin producing Escherichia coli O157:H7 strains isolated recent years in China to understand the epidemiological features caused by the pathogen.

METHODSPulsed field gel electrophoresis of large restriction fragments of bacterial chromosomal DNA was used.

RESULTSThe 51 isolates of E. coli O157:H7 collected in recent years in China could be divided into 8 Pulsed Field Gel Electrophoresis (PFGE) types based on the size and number of restriction fragments and patterns, that were digested by XbaI. Strains isolated from Ningxia province showed only two types- PFGE1 and PFGE2. Strains isolated in Xuzhou of Jiangsu province had 6 PFGE types. Isolates identified between 1986 - 1988 belonged to PFGE7. Strains isolated from patients in 1999 - 2000 were PFGE5 and PFGE3. Strains isolated from stool samples of domestic animal, food and vegetable were PFGE3 - 6, of which the predominant type was PFGE5. All of the 5 strains isolated from patients with diarrhea and hemolytic uremic syndrome (HUS) belonged to PFGE type 5, which was the dominant type of the isolates from stool samples of domestic animal and samples of food and vegetable contaminated.

CONCLUSIONData suggested that the cluster patients with diarrhea and HUS might have been related to the pathogens from domestic animas and contaminated food or vegetables. The distribution of PFGE types also varied in different provinces of China.

Electrophoresis, Gel, Pulsed-Field ; Escherichia coli O157 ; classification ; genetics ; pathogenicity ; Genotype ; Humans ; Shiga Toxin ; biosynthesis

To examine the genetic background of avian pathogenic Escherichia coli (APEC) that affects virulence of this microorganism, we characterized the virulence genes of 101 APEC strains isolated from infected chickens between 1985~2005. Serotypes were determined with available anti-sera and median lethal doses were determined in subcutaneously inoculated chicks. The virulence genes we tested included ones encoding type 1 fimbriae (fimC), iron uptake-related (iroN, irp2, iucD, and fyuA), toxins (lt, st, stx1, stx2, and vat), and other factors (tsh, hlyF, ompT, and iss). Twenty-eight strains were found to be O1 (2.0%), O18 (3.0%), O20 (1.0%), O78 (19.8%), and O115 (2.0%) serotypes. The iroN (100%) gene was observed most frequently followed by ompT (94.1%), fimC (90.1%), hlyF (87.1%), iss (78.2%), iucD (73.3%), tsh (61.4%), fyuA (44.6%), and irp2 (43.6%). The strains were negative for all toxin genes except for vat (10.9%). All the strains were classified into 27 molecular pathotypes (MPs). The MP25, MP19, and MP10 pathotypes possessing iroN-fimC-ompT-hlyF-iucD-tsh-iss-irp2-fyuA (22.8%), iroN-fimC-ompT-hlyF-iucD-tsh-iss (21.8%), and iroN-fimC-ompT-hlyF-iss (11.9%) genotypes, respectively, were predominant. Redundancy of iron uptake-related genes was clearly observed and some strains were associated with higher mortality than others. Therefore, strains with the predominant genotypes can be used for diagnosis and vaccine.
Animals ; Bacterial Proteins/genetics/metabolism ; Chickens ; Escherichia coli/*classification/genetics/*pathogenicity ; Escherichia coli Infections/epidemiology/microbiology/*veterinary ; Gene Expression Regulation, Bacterial/physiology ; Phylogeny ; Poultry Diseases/epidemiology/*microbiology ; Republic of Korea/epidemiology ; Virulence

OBJECTIVETo evaluate the etiology of Shiga like toxin producing Escherichia coli (SLTEC) in children with diarrhea.

METHODSWe designed and synthesized 3 pairs of primers located in the SLT1, SLT2, and eaeA genes of enterohaemorrhagic Escherichia coli (EHEC), while the virulent genes SLT1, SLT2, and eaeA from E.coli species were amplified by polymerase chain reaction (PCR).

RESULTSOne strain of EHEC with SLT1, SLT2, and eaeA in 29 reference strains of diarrhea-causing E.coli (DCEC) and 10 strains of other enterobacteria detected by PCR had positive reactions, while all other DCEC and enterobacteria were negative. Of 474 strains of E. coli isolated from 1032 children with diarrhea and detected by PCR, 20 strains of SLT1 producing E. coli (4.2%) positive, and 7 strains of SLT2 producing E. coli (1.5%) positive; while of 74 strains of entero-SLTs-producing and invasive Escherichia coli (ESIEC), 15 strains of SLT1 (20.3%) and 5 strains of SLT2 (6.8%) were positive.

CONCLUSIONShiga-like toxin E. coli has been identified as a major etiologic agent of children with diarrhea in Taiyuan, China.

Child ; Diarrhea ; microbiology ; Escherichia coli ; classification ; isolation & purification ; pathogenicity ; Feces ; microbiology ; Humans ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity ; Shiga Toxins ; genetics

To clarify the characteristics of the virulence factors (VFs) of ciprofloxacin resistant Escherichia coli (CFRE) with acute uncomplicated cystitis (AUC), we determined the VFs and the phylogenetic background of all 54 CFRE strains and the 55 randomly selected ciprofloxacin sensitive E. coli strains (CFSE) from patients with AUC in 22 Korean hospitals. The prevalence of the VFs was as follows: fimA, papEF, papGIII, sfaI, dafaBC, cnf1, and hlyA were presented in 96%, 54%, 68%, 91%, 49%, 72%, and 29% of the samples, respectively. The expressions of papEF, cnf1, and hlyA were significantly more prevalent in the CFSE. Moreover, the expressions of cnf, and papEF significantly reduced the risk of ciprofloxacin resistance. The CFSE was also marginally associated with the group B2 (P=0.05). Although the presence of pyuria and a previous cystitis history were not related with the phylotyping and the expressions of VFs, group B2, and fimA and papEF were more expressed in the younger age patients (P<0.05). In conclusion, the CFRE exhibits a selective loss of VFs and the non-B2 phylotype in Korean AUC patients. The group B2 and the presence of fimA and papEF are associated with a younger age of AUC patients.
Adolescent ; Adult ; Aged ; Asian Continental Ancestry Group/genetics ; Bacterial Typing Techniques ; *Ciprofloxacin/pharmacology/therapeutic use ; *Cystitis/drug therapy/microbiology/urine ; Drug Resistance, Bacterial/drug effects/*genetics ; *Escherichia coli/classification/genetics/pathogenicity ; Escherichia coli Infections/*drug therapy ; Female ; Genotype ; Humans ; Microbial Sensitivity Tests ; Middle Aged ; Phylogeny ; Prospective Studies ; Urine/*microbiology ; Young Adult