Reuter G
Institute for Food Hygiene, Meat Hygiene and Technology, Veterinary Department, Free University of Berlin, Germany.
Int J Food Microbiol. 1992 Oct;17(2):101-11. doi: 10.1016/0168-1605(92)90109-g.
Lancefield group D-streptococci are contaminants of various food commodities, especially those of animal origin. They encompass the new genus Enterococcus comprising 13 known species and some species of streptococci which have their habitat in the intestine of animals, e.g. Streptococcus bovis, suis and equinus. The serologically based grouping may no longer constitute the best definition for streptococci from the food chain. Food hygiene monitoring systems using enterococci as indicators need reliable methods for selective cultivation and identification of marker strains. Up to now more than 100 modifications of selective media have been described for isolating streptococci or enterococci from various specimens. The selection of a medium requires either experience or consultation. It depends on the kind of specimen, the method of cultivation (plate count or membrane filter) and whether or not the habitat is heavily contaminated with other organisms. The choice of media is made more difficult as commercial versions of the same culture medium may vary in recipe and/or performance from producer to producer. Therefore, reviewing the literature may help in the choice of medium and confirmation tests. The selectivity and productivity of some commonly used or cited media are reported here, partly based on our own experience: citrate azide tween carbonate agar (CATC), kanamycin aesculin azide agar (KAA) and M-enterococcus agar (ME) including earlier results with aesculin bile azide agar (ABA), and thallous acetate tetrazolium glucose agar (TITG). No medium was completely selective for all group D-streptococci or for all enterococci but some media were highly selective for a single Enterococcus species, e.g., for E. faecalis which serves as indicator of human pollution. Confirmatory tests must be carried out when experience in the evaluation procedure is limited. Selective media for enterococci should be used only after or while checking in parallel their selectivity and productivity against appropriate test organisms.
兰斯菲尔德D组链球菌是各种食品的污染物，尤其是动物源性食品。它们包括新的肠球菌属，该属包含13个已知种以及一些在动物肠道中生存的链球菌种，例如牛链球菌、猪链球菌和马肠链球菌。基于血清学的分组可能不再是食物链中链球菌的最佳定义。以肠球菌为指标的食品卫生监测系统需要可靠的方法来选择性培养和鉴定标记菌株。到目前为止，已经描述了100多种用于从各种标本中分离链球菌或肠球菌的选择性培养基的改良方法。选择培养基需要经验或咨询。这取决于标本的种类、培养方法（平板计数或膜过滤）以及栖息地是否被其他微生物严重污染。由于同一培养基的商业版本在配方和/或性能上可能因生产商而异，因此培养基的选择变得更加困难。因此，查阅文献可能有助于培养基的选择和确认试验。本文报道了一些常用或引用的培养基的选择性和产率，部分基于我们自己的经验：柠檬酸盐叠氮化物吐温碳酸盐琼脂（CATC）、卡那霉素七叶苷叠氮化物琼脂（KAA）和M-肠球菌琼脂（ME），包括早期使用七叶苷胆汁叠氮化物琼脂（ABA）和醋酸铊四氮唑葡萄糖琼脂（TITG）的结果。没有一种培养基对所有D组链球菌或所有肠球菌都具有完全选择性，但有些培养基对单一肠球菌种具有高度选择性，例如，对作为人类污染指标的粪肠球菌。当评估程序的经验有限时，必须进行确认试验。用于肠球菌的选择性培养基仅应在对照适当的试验菌株检查其选择性和产率之后或同时使用。
