TABLE 2.

Characterization of the 28 E. coli strains isolated from raw-milk cheeses

StrainIsolationaSerotypebPresence off:
stx (subtypec)eae (type)Hemo- lysiseEHEC-hlyAkatPespPnleApagCentefa1saaEAFbfpA
STEC
33.1CO2:H27+ (stx2a)+
162.5CO2:H27+ (stx2a)+
246.3CO2:H27+ (stx2a)+
104.5CO8:H19+ (stx2a + stx2d)E-hly+
303.1CO8:H19+ (stx2ND)
170.2I, CO26:H11+ (stx1a)+1)E-hly++++++
238.2IO26:H11+ (stx1a)+1)E-hly++++++
129.2IO26:[H11]+ (stx1a)+1)E-hly++++++
245.3IO26:[H11]+ (stx1a)+1)E-hly++++++
260.3IO26:[H11]+ (stx1a)+1)E-hly++++++
283.4IO26:[H11]+ (stx1a)+1)E-hly++++++
277.2IO26:[H11]+ (stx1a + stx2a)+1)E-hly+++++
161.2CO91:H10+ (stx2d)
282.2CO128ab:[H2]+ (stx1c)E-hly+
124.1CO166:[H28]d+ (stx2b + stx2c)
91.1CO174:H2+ (stx1a)E-hly++++
299.3CO175:H16+ (stx2a)E-hly++
311.2CO175:H16+ (stx2d)
381.1CO178:H19+ (stx2c)+
225.4CONT:H10+ (stx1c)+
47.1COr:H10+ (stx1c)+
180.ECOr:H10+ (stx1c)+
Non-STEC
04.2IO26:[H11]+1)α-hly+++
315.2IO26:[H11]+1)α-hly+++
306.DI[O26]:[H11]+1)α-hly+++
355.2IO26:H32
167.2IO103:H25+2/θ)E-hly++++
275.1CO133:H29d
  • a C, colony hybridization; I, immunomagnetic separation.

  • b Or, O rough. O and H types in brackets represent strains whose serotype could be determined by real-time PCR only and not by conventional serotyping.

  • c stx subtypes refer to prototype organisms (GenBank accession numbers in parentheses) as follows: stx1a, O157-EDL933 (M19473); stx1c, O174-DG131-3 (Z36901); stx2a, O157-EDL933 (X07865); stx2b, O118-EH250 (AF043627); stx2c, O157-E32511 (M59432); stx2d, O73-C165-02 (DQ059012); ND, not determined.

  • d These strains tested positive for ihp1O145 by real-time PCR.

  • e E-hly and α-hly, EHEC hemolytic and alpha-hemolytic phenotypes on red blood cell agar, respectively.

  • f +, present; −, absent.