Kérouanton A, Hennekinne J A, Letertre C, Petit L, Chesneau O, Brisabois A, De Buyser M L
Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches sur la Qualité des Aliments et des Procédés agro-alimentaires (AFSSA-Lerqap), 23 Avenue du Général de Gaulle, 94706 Maisons-Alfort cedex, France.
Int J Food Microbiol. 2007 Apr 20;115(3):369-75. doi: 10.1016/j.ijfoodmicro.2006.10.050. Epub 2007 Jan 17.
Enterotoxins produced by Staphylococcus aureus are responsible for staphylococcal food-poisoning outbreaks (SFPO). In France, SFPO are the second cause of food-borne diseases after Salmonella. However, very little is known about the strains involved. The objective of this study was to characterize the staphylococcal strains related to these SFPO through phenotypic and genotypic analyses. A total of 178 coagulase-positive staphylococcal isolates recovered from 31 SFPO (1981-2002) were screened through biotyping. Thirty-three strains representative of the different biotypes in each SFPO were further examined for SmaI macrorestriction-type, phage-type, resistance to various antimicrobial drugs, presence of staphylococcal enterotoxin (se) genes sea to sei, and production of enterotoxins SEA to SED. All these 33 strains were identified as S. aureus species: 27 were of human biotypes and six ovine or non-host-specific biotypes. Most (74.1%) strains reacted with group III phages. Eleven strains were resistant to at least two classes of antibiotics and among them, two were resistant to methicillin. Twenty-nine strains carried one or several of the eight se genes tested; the gene sea was most common (n=23), and often linked to sed (n=12) or seh (n=5). The novel se genes seg-i were in all cases associated with se genes sea to sed except for one strain which carried only seg and sei. Pulsed-Field Gel Electrophoresis (PFGE) of SmaI macrorestriction digests of the 33 strains discriminated 32 PFGE patterns grouped into nine biotype-specific clusters. All five strains carrying sea and seh were grouped together into the same sub-cluster. Three of the four se-gene-negative strains were in one PFGE cluster: all four should be tested for se genes not included in this study and, if negative, be further investigated for the presence of unidentified SEs.
金黄色葡萄球菌产生的肠毒素是导致葡萄球菌食物中毒暴发（SFPO）的原因。在法国，葡萄球菌食物中毒是继沙门氏菌之后食源性疾病的第二大病因。然而，对于其中涉及的菌株我们知之甚少。本研究的目的是通过表型和基因型分析来鉴定与这些葡萄球菌食物中毒暴发相关的葡萄球菌菌株。通过生物分型对从31起葡萄球菌食物中毒暴发事件（1981 - 2002年）中分离出的178株凝固酶阳性葡萄球菌进行筛选。从每起葡萄球菌食物中毒暴发事件中选取代表不同生物型的33株菌株，进一步检测其SmaI酶切大片段限制性类型、噬菌体类型、对各种抗菌药物的耐药性、葡萄球菌肠毒素（se）基因sea至sei的存在情况以及肠毒素SEA至SED的产生情况。所有这33株菌株均被鉴定为金黄色葡萄球菌：27株为人源生物型，6株为羊源或非宿主特异性生物型。大多数（74.1%）菌株能与III组噬菌体发生反应。11株菌株对至少两类抗生素耐药，其中2株对甲氧西林耐药。29株菌株携带所检测的8种se基因中的一种或几种；基因sea最为常见（n = 23），且常与sed（n = 12）或seh（n = 5）连锁。新型se基因seg - i在所有情况下均与sea至sed基因相关，只有一株菌株仅携带seg和sei。对这33株菌株的SmaI酶切大片段进行脉冲场凝胶电泳（PFGE）分析，区分出32种PFGE图谱，这些图谱分为9个生物型特异性簇。所有携带sea和seh的5株菌株被归为同一亚簇。4株se基因阴性菌株中的3株位于一个PFGE簇中：所有4株均应检测本研究未包含的se基因，若为阴性，则应进一步调查是否存在未鉴定的肠毒素。
