Table 1

Identification and further characterization of the 34 ESBL producers isolated from fecal samples of 586 healthy human carriers in Switzerlanda

Sample no.Serotypedβ-Lactamase(s) identifiedβ-Lactam antibiotic resistanceFurther resistances
1519O2:H48CTX-M-1 and TEM-1crsrrrrsbsbs
1038O8:H21CTX-M-1rsrrrrsbibsSXT, TE, CIP
2238O23:H16CTX-M-1 and TEM-1rirrrrsbsbsSXT, TE
2332O24:H26CTX-M-1 and TEM-1rirrrrsbsbsSXT, TE
2018O32:H19CTX-M-1rsrrrrsbsbsSXT, TE
2291O53:H18CTX-M-1 and TEM-1rirrrribsbsSXT, TE
2290O68:H21CTX-M-1rsrrribsbsbsSXT, TE
1559O107:H27CTX-M-1 and TEM-1rsrrrrsbsbsSXT, TE
2333Or:H26CTX-M-1 and TEM-1rirrribsbsbsSXT, TE
1348O20:H33CTX-M-2 and TEM-1rirrrrsbsbsSXT, TE
2294Ont:H7CTX-M-2 and TEM-1rrrrrrsbibsK, SXT, TE
1999O33:H4CTX-M-14rrrrrrsbrsTE, CIP
1545O153:H30CTX-M-14 and TEM-1rirrrrsbibsK, SXT, TE
1495Or:H51CTX-M-14rirrrrsbsbsSXT, TE
2310O1:H6CTX-M-15rrrrrribibsSXT, TE, CIP
1887O15:H1CTX-M-15rirrrrsbsbsGM, SXT, TE
2225O86:H4CTX-M-15rsrrrribibsSXT, CIP
150O88:H8CTX-M-15 and TEM-1rsrrrribibs
1866O102:H6CTX-M-15rrrrrribrsK, SXT, TE, CIP
503O102:H6CTX-M-15 and TEM-1rsrrrrribsK, SXT
506O123:H12CTX-M-15rsrrrrsbibsSXT, TE
1330O153:H6CTX-M-15rrrrrribibsK, GM, CIP
171O153:H6CTX-M-15 and TEM-1rirrrrrrsGM, SXT, TE, CIP
1024O153:H6CTX-M-15 and TEM-1rirrrribibsSXT, TE, CIP
2017O184:H2CTX-M-15rsrrrrsbsbsSXT, TE
2200Or:H5CTX-M-15rsrrrrrisSXT, TE, CIP
1507Ont:H21CTX-M-15 and TEM-1rrrrribsbsbsK, SXT, TE, CIP
1027Ont:H30CTX-M-15 and TEM-1crrrrrrsbsbsSXT, TE, CIP
  • a Abbreviations: AM, ampicillin; AMC, amoxicillin-clavulanic acid; CF, cephalothin; CXM, cefuroxime; CPD, cefpodoxime; CTX, cefotaxime; CAZ, ceftazidime; FEP, cefepime; FOX, cefoxitin; K, kanamycin; GM, gentamicin; SXT, trimethoprim-sulfamethoxazole; TE, tetracycline; CIP, ciprofloxacin; PB, polymyxin; s, sensitive; i, intermediate; r, resistant.

  • b It is known that many ESBL producers may appear susceptible or intermediate to oxyimino cephalosporins in vitro if CLSI criteria are applied strictly but do not respond to the respective therapies. Consequently, for clinical reporting these results have to be corrected to “resistant.”

  • c Query coverage, 100%; maximal identity, 99% (

  • d All isolates listed were identified as E. coli.