Gonzalez E A, Blanco J, Garabal I, Blanco M
Departamento de Microbiologia y Parasitologia, Universidad de Santiago de Compostela, Facultad de Veterinaria, Lugo, Spain.
J Med Microbiol. 1991 Feb;34(2):89-95. doi: 10.1099/00222615-34-2-89.
Enterotoxigenic Escherichia coli (ETEC) strains of serotype O153:H45 have been found recently to be a frequent cause of sporadic cases and outbreaks of neonatal diarrhoea in Spain and the most important cause of infant diarrhoea in Chile. Relationships between sugar fermentation patterns, resistance to antibiotics and plasmid profiles were analysed in nine E. coli O153:H45 strains isolated in Spain that synthesised CFA/I antigen and STa enterotoxin. Derivative strains obtained by curing with acridine orange, and transconjugants rendered antibiotic resistant, were characterised phenotypically and analysed for plasmid content. Two fermentation patterns were recognised: rhamnose fermenters (four strains) and rhamnose non-fermenters (five strains). The ability to ferment rhamnose was the only differential characteristic found among 49 carbohydrate fermentation tests used to establish fermentation patterns. All nine strains possessed similar plasmid profiles of three or four plasmids of 52-87 Mda. A non-conjugative large plasmid of 82 Mda or 87 Mda, depending upon the strain, was identified as that responsible for production of both CFA/I and STa. Resistance to antibiotics was determined by plasmids other than those coding for CFA/I and STa. Two conjugative resistance factors were identified: a 52-Mda plasmid coding for resistance to ampicillin, streptomycin and sulphonamide in rhamnose-fermenting strains, and a 77-Mda plasmid coding for resistance to ampicillin, streptomycin, kanamycin, tetracycline and sulphonamide in rhamnose non-fermenting strains. Our results support the hypothesis that the prevalence and distribution of ETEC strains belonging to serotype O153:H45 in Spain and Chile could be due to the extensive cultural relations between Spain and South American from the past.
最近发现，血清型为O153:H45的产肠毒素大肠杆菌（ETEC）菌株是西班牙散发性病例和新生儿腹泻暴发的常见病因，也是智利婴儿腹泻的最重要病因。对在西班牙分离出的9株合成CFA/I抗原和STa肠毒素的大肠杆菌O153:H45菌株的糖发酵模式、抗生素抗性和质粒图谱之间的关系进行了分析。用吖啶橙消除质粒获得的衍生菌株以及获得抗生素抗性的转接合子进行了表型特征分析，并分析了质粒含量。识别出两种发酵模式：鼠李糖发酵菌（4株）和鼠李糖非发酵菌（5株）。在用于确定发酵模式的49项碳水化合物发酵试验中，发酵鼠李糖的能力是唯一发现的差异特征。所有9株菌株都具有相似的质粒图谱，由3个或4个52 - 87 Mda的质粒组成。根据菌株不同，一个82 Mda或87 Mda的非接合大质粒被确定为负责产生CFA/I和STa的质粒。对抗生素的抗性由编码CFA/I和STa以外的质粒决定。鉴定出两种接合抗性因子：一个52 Mda的质粒，编码鼠李糖发酵菌株对氨苄青霉素、链霉素和磺胺的抗性；一个77 Mda的质粒，编码鼠李糖非发酵菌株对氨苄青霉素、链霉素、卡那霉素、四环素和磺胺的抗性。我们的结果支持这样一种假设，即血清型为O153:H45的ETEC菌株在西班牙和智利的流行和分布可能归因于西班牙和南美洲过去广泛的文化联系。
