Information on Services

SEROTYPING

O serotyping is performed following the procedure published by Orskov et al. 1977. Serology, Chemistry, and genetics of O and K antigens of Escherichia coli. Bacteriol. Rev. 41:667-710. The standard strains used are those described in the paper.
H typing is performed by the method described by Machado et al. 2000. Identification of Escherichia coli flagellar types by restriction of the amplified fliC gene. Res. Microbiol. 151:535-546

Virulent Testing by PCR

Presence of genes encoding for different virulence factors are tested by PCR using the protocols published in the following paper.
DebRoy, C. and Maddox, C. 2001. Assessing virulence of Escherichia coli isolates of veterinary significance. Animal Health Research Reviews 1: 129-140.

Detection of Toxins associated with E. coli

  • STa: Associated with cultures from bovine
  • STb: Mostly associated with cultures from porcine
  • LT: Mostly associated with cultures from porcine
  • Stx1: Associated with EHEC and STEC strains
  • Stx2: Associated with EHEC and STEC strains
  • CNF1: associated with urinary tract infection (UTI) in humans and animals
  • CNF2: associated with UTI in humans and animals

Detection of fimbriae and adhesin genes associated with E. coli

The presence of the following adhesin/fimbriae genes are determined by PCR technique.

  • F4 (K88): commonly associated with ETEC isolates from porcine.
  • F5 (K99)- associated with ETEC strains from porcine, bovine, and sheep.
  • F6(987P)- associated with strains from porcine.
  • F41- associated with ETEC strains isolated from porcine, bovine, and sheep.
  • F18 (F107)- associated with strains from porcine edema disease and postweaning diarrhea.
  • F1845- associated with strains from bovine.
  • CS31A- associated with septicemic and enterotoxigenic strains found in bovine and recently isolated from diarrheagenic strains from humans.
  • Eae (intimin)- associated with EHEC and EPEC strains.
  • BFP :bundle forming pilus associated with diarrheal diseases

Suggested PCR screening tests for detecting virulence attributes in E. coli isolates from different host


HostLTSTaSTbStx1Stx2CNF1CNF2EAEK88 K99  
Bovine X XXXXX  X
PorcineXXXXXXXXX X
EquineXXXXXXXX   
CanineXXXXXXXX   
FelineXXXXXXXX   
HumanXXXXXXXX   
AvianXXXXX   
 
Host987PF107CS31AF1845BFP Iss IutA IiroN HlyF OmpT
Bovine  XX       
PorcineXX         
Equine           
Canine           
Feline           
Human    X      
Avian    XXXXX X


Special Services

Screening petting zoo animals for the presence of E. coli O157 and STEC: The procedure has been described in the following publication ( DebRoy C. and Roberts E. 2006. Screening petting zoo animals for the presence of potentially pathogenic Escherichia coli. J. Vet. Diag. Invest.18: 597-600)

Monitoring fruits and vegetables for all pathogenic E. coli strains, EPEC, ETEC, EHEC, STEC, EAEC, EIEC and NTEC are conducted by standard procedures as developed by the Microbiological Data Program (MDP) of USDA.

ERIC-PCR is performed by the methods described by Meacham KJ et al. 2003 Evaluation of genotyping large numbers of Escherichia coli isolates by enterobacterial repetitive intergenic consensus PCR, J. Clin. Microbiol. 41: 5224-5226.

PFGE is performed by the method described by Gautom RK.1997. Rapid Pulsed-Field Gel Electrophoresis protocol for typing of Escherichia coli O157:H7 and other gram-negative organisms in 1 day. J Clin Microbiol. 35 :2977-80.

Contact Information

Chobi DebRoy, Ph.D.
Director
Email:

The Pennsylvania State University
E. coli Reference Center
115 Henning Building
University Park, PA 16802

Phone: 814-863-2630
Lab Phone: 814-863-2167

 

       

 
 

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