摘要
我国临床腹泻病人粪便标本中，约有６０％检不出任何已知病原，而能分离出几乎纯培养的大肠杆菌。这些大肠杆菌过去被误认为是肠道正常菌群。我们对在北京西城区三个医院从腹泻病患者粪便标本中分离的１７２株所谓正常大肠杆菌，进行了质粒ＤＮＡ、Ｈｅｐ－２细胞粘附试验，和１０种ＤＮＡ探针分析。结果发现这些所谓的肠道正常大肠杆菌并不正常，其中４４％可鉴定为致泻性大肠杆菌，包括ＥＨＥＣ１６株，占所检查菌株的９．３％；ＥＰＥＣ８株，占所检查菌株的４．７％，ＥＡｇｇＥＣ１１株占６．４％。还有５４株菌对Ｉｎｖ、ＳＬＴ１或ＳＬＴ２探针同时呈阳性反应，占所检查菌株的３１．４％。我们认为对Ｉｎｖ、ＳＬＴ１或ＳＬＴ２探针同时呈阳性反应的菌株是一种尚未在国际上报道的致泻性大肠杆菌，将其命名为“产志贺样毒素且具侵袭力的大肠杆菌”（Ｅｎｔｅｒｏ－ＳＬＴｓ－ｐｒｏｄｕｃｉｎｇａｎｄｉｎｖａｓｉｖｅＥ．ｃｏｌｉＥＳＩＥＣ）。与ＥＩＥＣ不同，ＥＳＩＥＣ虽能侵入Ｈｅｐ－２细胞，但不具有ｉｐａＢ基因，编码侵袭力的基因与ＥＩＥＣ有所不同。该类菌株虽对Ｈｅｐ－２细胞呈现集聚性粘附现象，但不与肠集聚性大肠杆菌（ＥＡｇｇＥＣ）探针起反应；产生肠毒素，细菌滤过液对Ｈｅ?
n clinical laboratories of Beijing, China.no known entero-pathogen but almost pure E. coli strains could be isolated from more than60% fecal samples of diartheal patients,which had been recognized as normal flora E.coliand dismissed. We suspected that some of the so-called normal flora E.coli strains might be virulent. To prove our idea,We collected 172strains of E.coli isolated from diatrheal pa-tients from whom no other enteric bacterialpathogens had been identified, including EPEC,EIEC,ETEC,With plasmid DNA analysis, Hep-2 cell adherence assay and 10 DNA probe hybridization, we found that the so-called nor-mal flora E.coli was abnormal. 44%of them were virulent, of which 16(9.3) were EHEC,8EPEC(4.7%) ,11 EAggEC(6.8%).Fifty-four of 172 strains were hybridized with INVand SLT1 or SLT2 probes,which had neverbeen reported,These strains could invade Hep-2cells,but were lack of ipaB gene,a key gene ofinvasiveness gene cluster of Shigella species andEIEC,The aggregetive adherence to Hep-2 cellswas observed,but the strains were not hybridizedwith EAggEC specific DNA probe,The purifiedtoxin protein and cell filtrate were toxic tovero cells.Based on the data obtained, we believedthat this is a new category of diarrhea-genic E.coll,nalned as entero-sLTguprodl1eing and invasiveE.coli(ESIEC).ESIEC occupied 31.4%of thestrains tested, isolation of it was probablyhigher than those of ETEC,EPEC in P R China.
出处
《中华流行病学杂志》
CAS
CSCD
北大核心
1994年第6期333-338,共6页
Chinese Journal of Epidemiology
