Study of the properties of E. coli of serological group 03 isolated in acute intestinal diseases]

The authors studied the properties of 115 strains of E. coli of serological group 03 isolated from 49 children and adults with acute intestinal disturbances. The majority of the children (82.9%) were aged under one year. Results of the study of the antigenic structure and biochemical properties permitted to differentiate the strains isolated into 3 serological types, with the prevalence of strains of type O3 : K2 (L) : H2 (78.3%), and 8 biochemical variants. The majority of the strains possessed hemolytic properties. Strains of serological group O3 were isolated repeatedly from the patients during the sickness, whereas none were revealed in examination of 132 healthy children and adults. The data obtained permitted to consider these microbes to be possible causative agents of intestinal coliinfection, and to refer them to the enteropathogenic category.     

Biochemical and serological characteristics of Escherichia belonging to the serological group 01]

A circulation at the territory of the country of various biochemical and serological variants of escherichia belonging to serological group O1, isolated in acute intestinal diseases of children and adults, was revealed. Nonhomogeneousness of the partial composition of the O-antigen was demonstrated; K-antigens were determined; new H-antigens were described. Of the 10 serological types of escherichia there proved to prevail O1 : K? : Hp and O1 : K1 : Hp; in group and sporadic acute intestinal diseases there were for the first time isolated O1 : K1 : H34, O1 : K1 : H20, O1 : K1 : Hp, O1 : K51 : H7, and O1 : K? : H20.     

Determination of colonization factor antigens CFA in diagnosis of enterotoxigenic strains of Escherichia coli]

This study was aimed at establishment whether preliminary determination of colonization factor antigens CFA may be useful in selection of potentially pathogenic strains of Escherichia coli with serological types belonging to ETEC and 750 isolates of E. coli from children with symptoms of diarrhoea. Enterotoxigenicity of strains was evaluated by suckling mice test and culture of Y1 cell tissue. Colonization factor antigens CFA were evaluated on the basis of slide agglutination and agar gel immunodiffusion with application diagnostic sera prepared for this study. Ability of enterotoxin production was found in 25% strains of E. coli with serological types belonging to ETEC. In 90% these strains were isolated from cases of epidemic diarrhoea. ETEC strains were found in 11% of hospitalized children and in 5% who were treated outside of hospital because of diarrhoea. MRHA adhesins occurred on 80% of ETEC strains were all diagnosed as CFA/I. CFA/II were not found and in only three strains non-fimbrial CFA/IV was present. Preliminary determination of CFA during selection of ETEC strains presents as a very sensitive method (97%) and is also highly specific (99%). Application of this method will result in significant increase of affectivity of biological tests directed toward determination of E. coli enterotoxigenicity.     

Antigenic properties of genetic recombinants of serologically typed E. coli]

The conjugation between the typed strains of E. coli belonging to various serological groups and conjugation between typed and untyped E. coli strains were studied. Genetic determinant controlling the synthesis of the O100 antigen proved to be closely linked with histidine locus. Among recombinants obtained in crossing the typed E. coli strains there were such belonging to the serological type different from the serological types of donor and recipient cells.     

Evidence for linkage between the swine L blood group and the loci specifying the receptors mediating adhesion of K88 Escherichia coli pilus antigens

Brush borders or enterocytes obtained from the small intestine of 248 pedigreed pigs were tested by adhesion assay in vitro with enterotoxigenic Escherichia (E.) coli strains, each expressing one of the three K88 pilus variants K88ab, K88ac and K88ad. All pigs were classified as belonging to one of the four adhesion phenotypes: I--K88ab(-), ac(-), ad(-); II--K88ab(-), ac(-), ad(+); III--K88ab(+), ac(+), ad(-); and IV--K88ab(+), ac(+), ad(+). Serum or red cells were typed for 15 blood group systems: A-O, B, C, D, E, F, G, H, I, J, K, L, M, N and O; for 11 biochemical polymorphisms: PI1, PI2, PO1A, A1BG, GPI, PGD, TF, HPX, ADA, PGM and AMY; the polymorphism at the IGHG1 locus. Linkage analysis was performed between the alleles at the locus (loci) specifying K88 receptors able to bind one or more different serological types of K88 E. coli and alleles for markers at other loci. Linkage was demonstrated between the locus for the L blood group system and the locus (loci) for K88 E. coli receptors (Z = 3.24), adding one locus (loci) to the previously identified linkage group IV (LGIV) [L-SLB]. The maximum likelihood estimate of the recombination fraction (theta) was 0.23. No evidence was found for linkage between any of the other biochemical and immunogenetic markers and the receptor locus (loci) of K88 E. coli.     

Characteristics of the serological passage of Escherichia isolated from children and adults with acute intestinal infections

The serological picture of Escherichia (5,910 strains), isolated from 1,430 inpatients (486 adults and 944 children) with acute intestinal infections by means of new diagnostic preparations (Escherichia rapid agglutinating O- and H-systems), was studied. In 15% of the adults and 26-28% of the children no Escherichia were detected. The serological picture of Escherichia proved to comprise 143 O-groups and 334 serovars; about 50% of the strains belonged to 11 prevailing O-groups: O1, O2, O4, O6, O7, O8, O9, O16, O21, O75, O85. The serological picture in the adults was more variegated than that in the children: from most of the patients (77.2%) Escherichia were isolated as a mixture of 2-9 serovars. The isolation rate of Escherichia monocultures and the incidence of Escherichia belonging to different O-groups were the same in patients of different ages, with the exception of groups O4, O6, O26, O55 and O111 which were more frequent in young children.     

Characterization of Escherichia coli serogroups causing meningitis, sepsis and enteritis. I. Serological properties and animal pathogenicity of O18, O78 and O83 isolates.

Escherichia coli O78: K80 strains isolated from an outbreak among premature and newborn infants with meningitis, sepsis and enteritis, from sporadic cases of enteritis and from healthy carriers were compared with one another and with different E. coli serogroups. The O78: K80 cultures uniformly failed to give the rabbit intestinal loop test and the guinea pig eye reaction and none of them contained L1 antigen. After intraperitoneal injection into mice, the organisms multiplied in the peritoneal cavity and caused bacteriaemia lasting at least 2 weeks. E. coli strains originating from septicaemia (O78: K80, O18a,c: K?, O83: K?) showed significantly lower LD50 values for mice (9 x 10(3)--7 x 10(5)) than did E. coli serogroups associated with infantile enteritis only (3 x 10(8)--7 x 10(8)). It is assumed that the isolates differ in pathogenicity not only from E. coli strains associated with "cholera-like" disease and with "dysenteriform" infection, but also from L1 antigen-containing cultures described in neonatal meningitis, and constitute a separate group characterized by an ability to cause meningitis, sepsis and enteritis within the same outbreak.     

Combinations of pathogenicity factors in Escherichia coli isolated from children and domestic animals

The study has shown that in E. coli strains isolated from children aged up to 1 year with acute intestinal diseases of unknown etiology different combinations of pathogenicity factors (Ent. K88, K99, Vir, CFAI, CFAII, HIy, ColV, ColI) can be detected in 47.1 +/- 3.8% of cases, while in E. coli strains isolated from practically healthy children of the same age combined carriership of these factors does not exceed 5.8 +/- 2.5%. In E. coli strains isolated from swine and cattle with diarrhea the combined carriership of pathogenicity factors is 68.5 +/- 2.8% and 58.4 +/- 4.9% respectively.     

Characteristics of E.coli O157 strains isolated in Poland from clinical material and food samples

E. coli belonging to the O157 serological group are among the organisms isolated most frequently out of all the so called entero-hemorrhagic E. coli strains (EHEC). Since several years they have been isolated also in Poland. The purpose of the present study was determination on selected phenotypic and genotypic properties of E. coli O157 strains isolated in our country from clinical material samples and from food. The serotype of the strains was determined, together with the following properties regarded as pathogenicity markers of verotoxic E. coli strains such as absence of beta-glucuronidase activity and sorbitol fermentation ability, as well as production of verotoxins SLT I and/or SLT II and entero-hemolysin. Besides that, by the PCR method the fragments of the genes coding for verotoxins, intimin and enterohaemolysin were amplified. The products of PCR were analysed by the restriction enzyme analysis (RFLP). All verotoxic E. coli O157 strains isolated in Poland were analysed by the pulsed field gel electrophoresis of genomic DNA (PFGE). The studied group comprised E. coli O157 strains, among them 40 strains were isolated from human faeces and 5 from food. The remaining strains were the reference E. coli O157:H7 EDL 933 and G 5244 strains and strains from NIH collection. The obtained results showed that the tested strains were a very varying population. 21 of them (all isolated from food, 11 from faeces and 5 reference strains) belonged to serotype O157:H7, five were not peritrichous O157:NM and the remaining ones had other ciliary antigen than H7. All strains isolated from food, reference strains and only 3 O157:NM strains isolated from humans were verotoxic. The strains from food and two reference strains produced only SLT II, 2 of 3 strains isolated from humans and one reference strain also produced only SLT II and the other produced both verotoxins. Apart from these 13 verotoxic strains all remaining strains caused sorbitol fermentation.     

Biological properties of enterotoxigenic Escherichia isolated from patients with acute intestinal diseases of unknown etiology

As the result of the comparative examination of adult patients with acute enteric diseases and normal adults, 173 E. coli enterotoxigenic strains were isolated (161 strains from the patients and 12 strains from normal persons). 83% of the isolated enterotoxigenic E. coli (ETEC) produced two enterotoxins: thermolabile (LT) and thermostable (ST). Enterotoxigenicity was most pronounced in the strains of ETEC belonging to the prevaling variant ST + LT +. The enterotoxigenic properties of ETEC were highly stable: the production of ST and LT in the strains remained unchanged after their storage for up to 4 years. The isolated ETEC comprised 48 serogroups and 61 strains. The strains belonging to the same seroval had a similar degree of toxigenicity. The strains belonging to different serovars considerably differed in the activity of their enterotoxins. The production of two kinds of enterotoxins in the isolated E. coli strains was inter-related: the strains with a high activity of ST were, as a rule, good producers of LT.     

Prevalence of avian-pathogenic Escherichia coli strain O1 genomic islands among extraintestinal and commensal E. coli isolates

Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include pathogens of humans and animals. Previously, the genome of avian-pathogenic E. coli (APEC) O1:K1:H7 strain O1, from ST95, was sequenced and compared to those of several other E. coli strains, identifying 43 genomic islands. Here, the genomic islands of APEC O1 were compared to those of other sequenced E. coli strains, and the distribution of 81 genes belonging to 12 APEC O1 genomic islands among 828 human and avian ExPEC and commensal E. coli isolates was determined. Multiple islands were highly prevalent among isolates belonging to the O1 and O18 serogroups within phylogenetic group B2, which are implicated in human neonatal meningitis. Because of the extensive genomic similarities between APEC O1 and other human ExPEC strains belonging to the ST95 phylogenetic lineage, its ability to cause disease in a rat model of sepsis and meningitis was assessed. Unlike other ST95 lineage strains, APEC O1 was unable to cause bacteremia or meningitis in the neonatal rat model and was significantly less virulent than uropathogenic E. coli (UPEC) CFT073 in a mouse sepsis model, despite carrying multiple neonatal meningitis E. coli (NMEC) virulence factors and belonging to the ST95 phylogenetic lineage. These results suggest that host adaptation or genome modifications have occurred either in APEC O1 or in highly virulent ExPEC isolates, resulting in differences in pathogenicity. Overall, the genomic islands examined provide targets for further discrimination of the different ExPEC subpathotypes, serogroups, phylogenetic types, and sequence types.     

Enterotoxigenic capacity of strains of Klebsiella and Enterobacter genera isolated in acute intestinal diseases in children

234 strains, including 104 K. pneumoniae strains, 28 K. oxytoxica strains, 64 E. cloacae strains and 40 E. aerogenes strains, have been isolated from the intestine of 266 children with diarrhea, aged up to 1 year, and studied for enterotoxigenicity. By the coagglutination test, made with G. Kronvall's staphylococcal reagent prepared with the use of antiserum to Escherichia coli LT-enterotoxin, and the biological assay on suckling mice enterotoxigenic activity has been revealed in 119 strains, including 48 K. pneumoniae strains (12.6%), 33 E. cloacae strains (27.4%) and 23 E. aerogenes strains (19.7%). The strains producing only LT-enterotoxins, only ST-enterotoxins, and both LT- and ST-enterotoxins have been found. The determination of the enterotoxigenic activity of the clinical isolates of opportunistic enterobacteria makes it possible to improve the etiological interpretation of acute intestinal infections.     

Serological variety of flagellar antigen H1 in natural Escherichia coli population

Abstract Variation of the Escherichia coli flagellar antigen H1 was studied among 120 human isolates belonging to more than 25 O:K serovars. Factor-specific antisera were prepared and shown to be useful in the identification of serological subtypes of H1. The three subtypes found were defined as H1abc, H1acd and H1abe. The H1abc corresponded to the standard flagellar antigen H1 present in 84% of all strains. It was found in all O groups except O15, O17 and O83. Eight O15 and two O17 strains studied were of subtype H1abe, while the one O83 strain studied was H1acd. Both subtypes H1abc and H1acd were found among strains within O6:K5, O6:K13 or O-non-typeable:K5 serovars.     

Prevalence of enteroaggregative and other HEp-2 cell adherent Escherichia coli in asymptomatic rural south Indians by longitudinal sampling

Enteroaggregative and other HEp-2 cell adherent Escherichia coli can produce acute and persistent diarrhoea in children and adults, but their prevalence in asymptomatic individuals in the community is not known. In this study, faecal specimens were obtained at 3-4 monthly intervals from 349 subjects constituting a 20% age-stratified sample of a rural community for a period of two years. HEp-2 cell adherent E. coli were found in 210 subjects, and repeat isolations of enteroaggregative E. coli belonging to the same serogroup were found in 12.6% of children less than 12 years of age, indicating that this organism can asymptomatically colonise the intestinal tract. These children may act as a reservoir of infection for the community.     

Occurrence of P.fimbrii in strains from selected genera of Enterobacteriaceae]

This study was aimed at recognition of frequency of occurrence of P fimbriae in strains of Escherichia coli isolated from samples of feces of children with symptoms of diarrhoea and at search of these adhesions in strains representing other than Escherichia genera of Enterobacteriaceae strains. One hundred forty laboratory strains were investigated. They belonged to genus Citrobacter, Enterobacter, Hafnia, Klebsiella, Morganella, Proteus, Providencia, Salmonella, Shigella, and Yersinia. Also were tested 1277 colonies of enteric rods isolated from the MacConkey's medium inoculated with samples of feces from 163 children with symptoms of diarrhoea. Mannose-resistant active hemagglutination test was performed with human group O erythrocytes and guinea pig erythrocytes stabilized with glutaraldehyde. Presence of P fimbriae was detected by the slide latex test with latex covered by P1 glycoprotein. Among 140 laboratory strains of Enterobacteriaceae in 21 strains (3-E. cloaceae, 2-Hafnia, 13-K. pneumoniae, 2-P. rettgeri and in one strains of Providencia) presence of MRHA adhesins was demonstrated. Nine of these strains (2-Hafnia, 5-K. pneumoniae and 2-P. rettgeri) reacted specifically in the latex test. Among 1142 colonies of E. coli isolated from children with symptoms of diarrhoea, 326 colonies belonged to 13 EPEC serotypes. With 118 (36.2%) of EPEC colonies a positive result of MRHA reaction was found with human erythrocytes and 34 (10.4%) with guinea pig erythrocytes. Positive latex test was obtained with 77 (23.6%) colonies. All these colonies possessed MRHA adhesins. Remaining 816 colonies of E. coli strains did not represent microorganisms belonging to serotypes accepted as enteropathogenic. From 112 (13.7%) colonies out of 816 not belonging to EPEC, positive results was obtained in the MRHA test with human erythrocytes and this was the case also with 41 (5.0%) colonies in MRHA reaction with application of guinea pig erythrocytes. The latex test was positive in 65 (7.9%) colonies of E. coli. From remaining 135 colonies other than E. coli, positive result of latex test of presence of P fimbriae was obtained with 54 (40.0%) colonies, including 14 colonies of E. cloacae, 23-K. pneumoniae and 17-K. oxytoca. In all these strains presence of MRHA adhesins was demonstrated. These investigations demonstrated that among EPEC strains significantly more frequently, than not belonging to these serotypes of E. coli, MRHA adhesins, including P fimbriae was observed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Origin of plague moderate phages of serotype 2]

Results of study of the negative colonies morphology, the structure of corpuscles, antigenic properties, specificity, and the action range permitted to refer the phages obtained from 18 E. coli strain, 1 plaque strain, and 1 pseudotoberculosis bacillus strain to the same group and to identify them with plague phages of serological type 2. Isolation of the same phage type from different bacterial species permits to regard them as "polyhostal" ones. E. coli should be considered as the main carrier of phages belonging to serological type 2. It is suggested that phages existing on microbes belonging to different species should be called "polyhostal".     

大肠杆菌F18菌毛及其亚型的PCR鉴定

F18菌毛是产肠毒素大肠杆菌 (ETEC)与产vero细胞毒素大肠杆菌 (VTEC)的重要致病因子 ,可介导细菌对小肠细胞的黏附 ,并具有F18ab和F18ac 2个抗原亚型。根据已发表的F18ab菌毛A亚单位 (FedA ab)的基因 (fedA ab)设计 3条引物 ,建立了 2种聚合酶链式反应 (PCR)扩增方法。通过对F18ab 大肠杆菌、F18ac 大肠杆菌、K88 大肠杆菌、K99 大肠杆菌、987P 大肠杆菌、F4 1 大肠杆菌的试验 ,结果表明所建立的PCR方法可特异性鉴定F18 大肠杆菌并区别其亚型F18ab与F18ac     

Effects of monocolonization with<Emphasis Type="Italic">Escherichia coli</Emphasis> strains O6K13 and nissle 1917 on the development of experimentally induced acute and chronic intestinal inflammation in germ-free immunocompetent and immunodeficient mice

Germ-free immunocompetent (BALB/c) and immunodeficient (SCID) mice were colonized either by E. coli O6K13 or by E. coli strain Nissle 1917 and intestinal inflammation was induced by administering 2.5% dextran sulfate sodium (DSS) in drinking water. Controls were germ-free mice which demonstrated only mild inflammatory changes after induction of an acute intestinal inflammation with DSS as compared with conventional mice in which acute colitis of the colon mucosa similar to human ulcerative colitis is elicited. In mice monocolonized with the nonpathogenic E. coli Nissle 1917 the inflammatory disease did not develop (damage grade 0) while animals monocolonized with uropathogenic E. coli O6K13 exhibited inflammatory changes similar to those elicited in conventionally reared mice (damage grade 3). In the chronic inflammation model, immunocompetent BALB/c mice monocolonized with E. coli Nissle 1917 showed no conspicuous inflammatory changes of the colon mucosa whereas those monocolonized with E. coli O6K13 developed colon inflammation associated with marked infiltration of inflammatory cells. In contrast to germ-free immunodeficient SCID mice that died after application of DSS, the colon mucosa of SCID mice monoassociated with E. coli Nissle 1917 exhibited only moderate inflammatory changes which were less pronounced than changes of colon mucosa of SCID mice monoassociated with E. coli O6K13.     

Conjugative transfer frequency of resistance genes from ESBL-producing Enterobacteriaceae strains isolated from patients hospitalized in pediatric wards

The aim of this study was to evaluate the transfer frequency of plasmids encoding extended-spectrum beta-lactamases (ESBLs) from clinical isolates of Enterobacteriaceae to E. coli K12 C600 recipient strain. Additionally, resistance patterns to antimicrobial drugs of the isolates as well as transconjugants were analyzed. Fifty-four clinical strains belonging to the Enterobacteriaceae family were isolated from children hospitalized in Medical University Hospital in Wroc?aw. All the strains studied were identified in automatic ATB system using ID32E tests. Besides, they were ESBL-positive as was confirmed by the double-disc synergy test (DDST). The minimal inhibitory concentration (MIC) was determined for twelve selected antibiotics and chemotherapeutics. The majority of the strains (87%) were able to transfer plasmid-mediated ESBL to E. coli K12 C600 recipient strain with a frequencies ranged from 10(-5) to 10(-1) per donor cell. All the isolates studied as well as their transconjugants were susceptible to imipenem, meropenem and norfloxacin (MIC <1mg/L). On the other hand, these strains displayed high level of resistance (MIC 512 - >1024 mg/L) to cefotaxime, ceftriaxone, gentamycin, amikacin and cotrimoxazole. Genetic markers conferring resistance to aminoglycosides and cotrimoxazole were often co-transferred to recipient strain in conjugation process.     

Fimbriation, surface hydrophobicity and serum resistance in uropathogenic strains of Escherichia coli

Abstract A total of 80 Escherichia coli strains were examined for expression of P-fimbriae, mannose-sensitive haemagglutination (MSHA) and mannose-resistant haemagglutination (MRHA) of human group A erythrocytes and guinea pig erthrocytes, cell surface hydrophobicity and resistance to serum bactericidal activity. Isolates were obtained from urine of children and adults, either with acute pyelonephritis ( n = 15 and n = 12) or lower urinary tract infection (UTI) ( n = 30 and n = 23, respectively). Results obtained showed that, in E. coli strains isolated both from children and adults with lower UTI, significant differences were not found concerning the incidence of P-fimbriae, cell surface hydrophobicity and serum resistance. In pyelonephritogenic E. coli isolated from children and adults, the incidence of P-fimbriae and cell surface hydrophobicity was associated more frequently with the former (87% vs. 42% and 100% vs. 67%, P < 0.05), while serum resistance was associated with the latter (47% vs. 67%, P < 0.05).