Antibiotic resistance pattern of enterotoxigenic Escherichia coli isolated from infants and young adults in Israel

BACKGROUND: The usual methods of closure of major chest and abdominal wall defects have significant disadvantages. Skin grafts provide no structural support and result in incisional hernias. Synthetic mesh requires skin cover and is prone to infection and wound breakdown. The tensor fasciae latae (TFL) myocutaneous flap offers skin cover and a semi-rigid fascial layer. We document our unit's experience in pedicled and free TFL flaps. METHODS: The TFL flap closure of trunk defects was undertaken in 10 patients between August 1989 and April 1997. All cases were not amenable to primary closure and repair with synthetic mesh or skin grafts. RESULTS: The defect was satisfactorily repaired in all cases without subsequent herniation. The closure techniques using a pedicled TFL flap and a TFL flap for a free-tissue transfer are described. CONCLUSIONS: We conclude that the TFL flap is the method of choice for repairs of major truncal defects.     

Binding of enterotoxigenic Escherichia coli to isolated enterocytes and intestinal mucus

Binding of human enterotoxigenic Escherichia coli (ETEC) to the small intestine is a prerequisite for colonization and is mediated by colonization factor (CF) antigens. Coli surface antigen 6 (CS6) is considered a CF but binding to isolated enterocytes has not been established. In this study bacteria expressing CS6 were analysed for binding to enterocytes from human and rabbit small intestine, isolated using either an EDTA-containing buffer or a buffer devoid of EDTA. We found that the bacteria bound to enterocytes from rabbit ileum and human duodenum, but only when the cells had been isolated in the absence of EDTA. Pretreatment of rabbit enterocytes with meta-periodate resulted in a decreased proportion of cells with bound bacteria. Purified CS6, and for comparison other ETEC CFs, were also tested for binding to different human and rabbit mucus fractions. These analyses showed that purified CS6 bound to mucus from rabbit duodenum and ileum as well as from human duodenum, jejunum and ileum and that this binding was abolished by pretreatment of the mucus material with meta-periodate or Proteinase K. CFA/I, CS1 to CS5, CS7, CS17, putative CF (PCF) O159 (CS12), PCFO166 (CS14), and CFA/III (CS8) also bound to the rabbit mucus material although with different patterns; the binding of CS2 and CS5 was abolished by meta-periodate treatment. Thus, ETEC bacteria expressing CS6 might bind to carbohydrate-containing structure(s) in the apical membrane of isolated rabbit ileal and human duodenal enterocytes that could probably be released by EDTA treatment. In addition, CS6 and other ETEC CFs bind to component(s), in some instances protein-associated carbohydrate structures, in mucus fractions from small intestine.     

Enteropathogenic and enterohaemorrhagic Escherichia coli: more subversive elements

Enteropathogenic (EPEC) and enterohaemorrhagic Escherichia coli (EHEC) constitute a significant risk to human health worldwide. Both pathogens colonize the intestinal mucosa and, by subverting intestinal epithelial cell function, produce a characteristic histopathological feature known as the 'attaching and effacing' (A/E) lesion. Although EPEC was the first E. coli to be associated with human disease in the 1940s and 1950s, it was not until the late 1980s and early 1990s that the mechanisms and bacterial gene products used to induce this complex brush border membrane lesion and diarrhoeal disease started to be unravelled. During the past few months, there has been a burst of new data that have revolutionized some basic concepts of the molecular basis of bacterial pathogenesis in general and EPEC pathogenesis in particular. Major breakthroughs and developments in the genetic basis of A/E lesion formation, signal transduction, protein translocation, host cell receptors and intestinal colonization are highlighted in this review.     

Isolation of enterotoxigenic Escherichia coli from British troops in Saudi Arabia

Specimens from 181 patients with diarrhoea were examined by a Military General Hospital in a 3-month period during deployment of troops to Saudi Arabia in 1990/1. DNA probes for heat labile (LT) and heat stable (ST) enterotoxin genes identified enterotoxigenic Escherichia coli (ETEC) in 47 of the specimens (26%) and 49 ETEC strains were isolated. The majority (55%) belonged to a novel ETEC serotype having the O-antigen 159 and a flagellar antigen designated as a provisional new type. They produced ST and the coli surface associated antigen (CS)6. Strains of serotype O6:H16 represented 22% of the ETEC examined. They produced ST, LT and CS3 together with either CS1 or CS2. The remaining ETEC belonged to seven O:H serotypes. Overall, ST was the only enterotoxin gene identified in 73% of the ETEC and 67% of the strains expressed CS6 in the absence of other colonization antigens. Resistance to three or more antibiotics was observed in 53% of the ETEC, including most of the O159 strains.     

Detection of Shigella and enteroinvasive Escherichia coli using polymerase chain reaction

Two oligonucleotide primers were used in a polymerase chain reaction (PCR) procedure to amplify a region of the invasive-associated locus (ial) of Shigella and enteroinvasive Escherichia coli (EIEC). Detection of the amplified product can be done by agarose gel electrophoresis, which is specific and sensitive enough for routine diagnosis of these two pathogens. PCR is done using DNA extracted directly from faeces. The procedure can be completed in 7 h. These findings demonstrate a novel method for rapid, sensitive, specific, and simple diagnosis of diarrhoea caused by Shigella and EIEC.     

Biotyping of Campylobacter strains isolated in Lagos, Nigeria using the modified Preston biotype

Fifty-eight Compylobacter strains were isolated from children with diarrhoea at various health centres in Lagos and from healthy chicken. Twenty-nine strains of Campylobacter were isolated from humans, while the same number were isolated from chicken. The strains were biotyped using the modified Preston biotype scheme. The Preston biotyping results have been compared with the results of Penner serotyping. Out of fifty-eight strains studied, the technique identified ten strains (17%) as C. coli, three (5%) as C. lari and fourty-five (78%) as C. jejuni, by the coding system. This technique identified twenty-eight Campylobacter species. This method highlights the usefulness of this technique in the biotyping of local strains, however, when the two schemes are used in combination they give excellent typing results suitable for epidemiological purposes.     

Selective isolation from HeLa cell lines of Yersinia pseudotuberculosis, pathogenic Y. enterocolitica and enteroinvasive Escherichia coli

Using HeLa cell lines, we obtained an optimal and selective isolation of Yersinia pseudotuberculosis, pathogenic Y. enterocolitica and enteroinvasive Escherichia coli from samples such as pork, feces and river water heavily contaminated with other bacteria.     

Identification of enteroinvasive Escherichia coli and Shigella strains in pediatric patients by an IpaC-specific enzyme-linked immunosorbent assay

A new method, a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) recognizing a secreted, invasion plasmid-coded protein antigen (IpaC), was used to identify enteroinvasive Escherichia coli and Shigella strains among colonies from 859 cultures of fecal samples from children in Kuwait. A total of 33.8% of the samples were diarrheal. By the immunoassay, enteroinvasive E. coli strains were identified from two diarrheal samples but from none of the samples from children without diarrhea. These strains were fully virulent and belonged to serogroup O28ac. In addition, 26 Shigella strains were also recognized by the ELISA, while only 23 were isolated by routine biotyping and serotyping. For two diarrheal patients, Shigella was identified by culture only. The study showed that the IpaC-specific immunoassay is a simple and useful tool for identifying enteroinvasive strains. Furthermore, by reporting the first enteroinvasive E. coli isolates from Kuwait, the study indicates the presence of this group of pathogens as a potential source of diarrhea in the region.     

The antibacterial effect of honey on diarrhoea causing bacterial agents isolated in Lagos, Nigeria

The antibacterial effect of local honey on local isolates of bacterial agents of diarrhoea was determined by an in vitro method involving the impregnation of filter paper discs in undiluted honey and different honey concentrations ranging from 10%-50%. The discs were later placed on plates that have been seeded with the different bacteria and zones of inhibition of growth were measured after a 48 hr. period of incubation. Results presented show that undiluted honey and honey at concentrations of 40% and above were inhibitory to all enteropathogens tested. Zones of inhibition of growth around the disc margin of the various enteropathogens tested ranged from 16-18mm in diameter for the local undiluted honey and 7-12mm in diameter for concentrations of honey at 40% and 50%. The possible mechanisms of this inhibitory effect of local honey are discussed.     

Both 987P and F41 fimbriae produced by the same enterotoxigenic Escherichia coli strain isolated from a piglet with diarrhea

An enterotoxigenic Escherichia coli strain isolated from a piglet with diarrhea was examined for the presence of fimbriea 987P and F41 by a direct agglutination (with MAbs), an indirect immunofluorescence technique (MAbs as first antibodies), SDS-PAGE and Western blots (antisera IgG as probes). Results of these techniques revealed that both 987P and F41 fimbrial adhesins were produced by the same strain, not by separate ones.     

Antibody responses in humans against coli surface antigen 6 of enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) strains expressing only coli surface antigen 6 (CS6) have previously been isolated from patients with diarrhea, but the immunogenicity of CS6 has not been established in humans. We have detected CS6-specific immunoglobulin A responses in the feces and blood of patients convalescing from natural ETEC disease and of volunteers given an oral ETEC vaccine.     

Enteropathogenicity markers in Escherichia coli isolated from infants with acute diarrhoea and healthy controls in Rio de Janeiro, Brazil

Faeces from urban children < 2 years old with acute diarrhoeal illness and from non-diarrhoeal infants (controls) were examined for Escherichia coli and other enteropathogens. A total of 990 E. coli isolates from 100 patients and 50 controls was tested for enteropathogenic E. coli (EPEC) serotype (O:H), adherence to HEp-2 cells after incubation for 3 and 6 h, fluorescent actin staining (FAS), DNA hybridisation with EAF, eaeA, STh, STp and EAggEC probes and production of heat-labile enterotoxin (LT) and verocytotoxin (VT) with Y1 and Vero cells. EPEC were the most prevalent enteropathogens in patients (32.7%; and 14% in controls). Enteroinvasive E. coli (EIEC) and Vero cytotoxin-producing E. coli (VTEC) were not detected. The rate of isolation of enterotoxigenic E. coli (ETEC) was identical in both groups. Among the EPEC isolates the prevalent serotypes were O111:H2, O55:NM and O119:H6. Localised adherence (LA) was found significantly more frequently in isolates from patients (19.6%) than controls (2.1%). All LA-positive EPEC isolates were FAS+ and eaeA+, but only 75.2% of them hybridised with the EAF probe. Diffusely adhering E. coli (DAEC) and enteroaggregative E. coli (EAggEC) were found with equal frequency in patients and controls. Twenty-seven E. coli isolates were negative for EAF but positive for eaeA and FAS and produced LA in 6-h adherence tests. These EAF-/eaeA+ strains were the only putative enteropathogen identified in seven patients and were not found in controls. The ability of these strains to elicit ultrastructural cell alterations and cell-signalling events was evaluated in Caco-2 cells (human colon carcinoma cell line) by the gentamicin invasion assay and by transmission electron microscopy. The numbers of intracellular bacteria in cell invasion tests varied from 0.4% to 1.6% of the cell-associated bacteria after a 6-h incubation period. Tyrosine phosphorylation of host cell proteins was assessed in HEp-2 cells by immunofluorescence microscopy and all strains gave positive results. EAF-/eaeA+ E. coli strains express most of the virulence properties found among true EPEC strains and can be a relevant cause of infant diarrhoea in developing countries.     

Resistance to fluoroquinolones in Escherichia coli isolated from poultry

Quinolone-resistant Escherichia coli strains were isolated from poultry clinical samples in Saudi Arabia. The poultry flocks had been treated with oxolinic acid or flumequine prophylaxis. The measure of the uptake of fluoroquinolones showed that none of the strains had a reduced accumulation of quinolones. The result of complementation with the wild-type E. coli gyrA gene, which restored fluoroquinolone susceptibility, and the isolation of DNA gyrase from six isolates indicated that the resistant strains had an altered DNA gyrase. The minimum effective dose of ciprofloxacin for inhibition of supercoiling catalyzed by the isolated gyrases varied from 0.085 microgram/ml for a susceptible isolate (MIC < 4 micrograms/ml) up to 96 micrograms/ml for the more resistant one (strain 215, MIC > 64 micrograms/ml). For the same two isolates, the minimum effective doses of sparfloxacin varied from 0.17 up to 380 micrograms/ml. The in vitro selection of spontaneous single-step fluoroquinolone-resistant mutants using ciprofloxacin suggested that the more resistant mutants are likely the result of several mutations. These results also show that, as in human medicine, cross-resistance between older quinolones and fluoroquinolones can exist in veterinary isolates and reiterate the need for the prudent use of these drugs.     

Structural determination of the O-antigenic polysaccharide from the enterotoxigenic Escherichia coli O147

The structure of the O-antigenic polysaccharide from enterotoxigenic Escherichia coli O147 has been determined by NMR spectroscopy, and component and methylation analyses. The sequence of the sugar residues could be determined by NOESY and heteronuclear-multiple-bond-connectivity NMR experiments. It is concluded that the polysaccharide is composed of tetrasaccharide repeating units with the following structure: -->4)-beta-D-GalpA-(1-->3)-beta-D-GalpNAc-(1-->2)-alpha-L-Rhap+ ++-(1-->2)-alpha-L-Rhap-(1-->, where Rha represents 6-deoxymannose. The O-antigen of E. coli O147 is identical to the repeating unit of Shigella flexneri serotype 6 lipopolysaccharide, except that the latter contains an O-acetyl group at C3 of the rhamnosyl residue substituted by the N-acetylgalactosamine residue. Immunochemical analyses using a monoclonal antibody specific for the S. flexneri serotype 6 O-antigen showed an identical reactivity with both lipopolysaccharides.     

Morphological patterns of paediatric solid cancer in Lagos, Nigeria

With successful implementation of the Expanded Programme on Immunisation (E.P.I.), many Nigerian children are protected against the common infections of childhood which claim their lives within the first decade of existence. Recent observations tend to show that paediatric cancer may start to play a significant role in childhood morbidity and mortality. Therefore, this study analyses 372 cases of paediatric solid malignant tumours received at the Department of Morbid Anatomy, Lagos University Teaching Hospital (L.U.T.H) from 1974 to 1988. Considering all the age groups together, the commonest malignant tumour is lymphoma (32.8%), of which Burkitt's lymphoma accounts for 19.6%. Retinoblastoma and Wilms' tumour represent second and third commonest solid cancers respectively. There is, however, slight variation in the different age groups. For example, in the age group 1-4 years, malignant lymphoma is an uncommon disease representing only 11.0% of all cancers whilst retinoblastoma (34.5%) and nephroblastoma (24.0%) together account for 58.6%. Epithelial cancer although rare in children, represents 12.6% in the 10-14 year age group. There is a higher incidence of this tumour when compared to the other age groups (less than 1 year, 1-4 years and 5-9 years). Intracranial neoplasia are uncommon, representing only 2.0%. The overall incidence of solid malignant tumours in children aged 0-14 years in Lagos is estimated to be 22 per million person years.     

Prevalence of enteropathogenic and enterotoxigenic Escherichia coli in children with and without diarrhoea in Esteli, Nicaragua

OBJECTIVE: To assess some of the employment experiences of people with diabetes mellitus and to compare their experiences with those of a non-diabetic sibling control group. DESIGN: A questionnaire about employment experiences was administered to diabetic subjects aged 16-39 years, and an abbreviated questionnaire was administered to their eligible siblings. SETTING: The Illawarra area of New South Wales. PARTICIPANTS: The names of diabetic subjects were obtained from the Illawarra diabetes register. RESULTS: Interviews were conducted with 184 of 226 (81.4%) eligible diabetic subjects and with 70 eligible siblings. There were no significant differences between the diabetic subjects and their siblings with respect to educational achievements and rates of employment. Siblings reported a mean of 2.6 days sickness absenteeism in the year prior to the survey. Diabetics were absent from work for a mean of 4.5 days for reasons not related to their diabetes and for a mean of 2.6 days for diabetic causes. Within the diabetic group, 50% felt that having diabetes would make it more difficult to find another job, 33.7% felt that diabetes would influence their search for alternative employment and 19.6% felt that at some stage they had been refused employment because of their diabetes. Fifteen per cent of diabetics were aware of an example of discrimination and 24.2% of diabetics in employment had at some stage tried to hide their diagnosis from their employer. CONCLUSIONS: Diabetics do not appear disadvantaged compared with their siblings with respect to employment participation but are more likely to be absent from work due to sickness. However, many diabetic subjects had experienced a job refusal, had tried to hide their diagnosis from employers, were aware of examples of discrimination and were very negative about future employment prospects.     

Virulence genes of Shiga toxin-producing Escherichia coli isolated from food, animals and humans

The cold shock protein CspB from Bacillus subtilis is only marginally stable, but it folds extremely fast in a simple N reversible U two-state reaction. The corresponding cold shock proteins from the thermophile Bacillus caldolyticus and the hyperthermophile Thermotoga maritima show strongly increased conformational stabilities, but unchanged very fast two-state refolding kinetics. The absence of intermediates in the folding of B. subtilis CspB is thus not a corollary of its low stability. Rather, two-state folding and an unusually native-like activated state of folding seem to be inherent properties of these small all-beta proteins. There is no link between stability and folding rate, and numerous sequence positions exist which can be varied to modulate the stability without affecting the rate and mechanism of folding.     

Continuous and common epitopes present in fimbriae of enterotoxigenic Escherichia coli (ETEC)

Colonization factor antigens (CFAs and PCFs) are important virulence factors of Escherichia coli (ETEC) diarrhea. Antibodies to CFAs produced after ETEC infection are protective; however, the CFA epitopes which induce protective antibodies have not yet been characterized. This study is the characterization of the immune response to CFAs at molecular level and identification of the epitopes associated with inhibition of cell-adherence and protection that will lead to the development of methods to prevent ETEC infection and disease. The aim of this study was the characterization of the linear epitopes of CFA/I that react with sera from acute and convalescent phase of ETEC-in-fected children, with adult sera from endemic and non-endemic areas, with monoclonal antibodies (Mabs) and with hyperimmune antiserum to CFAs and PCFs different from CFA/I. Three linear and common epitopes were recognized among the CFA/I in child sera and adult sera from endemic areas and with hyperimmune sera against other known CFAs and putative ETEC colonization factors.     

Characterization of a second lysine decarboxylase isolated from Escherichia coli

We report here on the existence of a new gene for lysine decarboxylase in Escherichia coli K-12. The hybridization experiments with a cadA probe at low stringency showed that the homologous region of cadA was located in lambda Kohara phage clone 6F5 at 4.7 min on the E. coli chromosome. We cloned the 5.0-kb HindIII fragment of this phage clone and sequenced the homologous region of cadA. This region contained a 2,139-nucleotide open reading frame encoding a 713-amino-acid protein with a calculated molecular weight of 80,589. Overexpression of the protein and determination of its N-terminal amino acid sequence defined the translational start site of this gene. The deduced amino acid sequence showed 69.4% identity to that of lysine decarboxylase encoded by cadA at 93.7 min on the E. coli chromosome. In addition, the level of lysine decarboxylase activity increased in strains carrying multiple copies of the gene. Therefore, the gene encoding this lysine decarboxylase was designated Idc. Analysis of the lysine decarboxylase activity of strains containing cadA, ldc, or cadA ldc mutations indicated that ldc was weakly expressed under various conditions but is a functional gene in E. coli.     

Seroprevalence study of HTLV-1 and HIV infection in blood donors and patients with lymphoid malignancies in Lagos, Nigeria

OBJECTIVE: To document the seroprevalence of HTLV-1 and HIV in blood donors and in patients with lymphoma and leukaemia in Lagos metropolis. DESIGN: Cross sectional. SETTING: The Lagos University Teaching Hospital (LUTH) and General Hospital, Lagos (GH). SUBJECTS: 406 apparently healthy voluntary blood donors from the LUTH and GH and 30 patients [20 patients with histological diagnosis of Non-Hodgkin's Lymphoma (NHL) and 10 patients with diagnosis of Chronic Lymphocytic Leukaemia (CLL)] were recruited at LUTH. MAIN OUTCOME MEASURES: HTLV-1 and HIV-1 seroprevalence. RESULTS: Out of 406 donors, three (0.7%) were positive for HTLV-1 and 20 (4.9%) were positive for HIV-1. None of the 30 patients with NHL or CLL were positive for HTLV-1. Five of NHL patients were positive for HIV-1. CONCLUSION: HTLV-1 seroprevalence is low among Lagos donors. Routine screening of donors for this virus will not be cost effective. NHL is one of the AIDS related malignancies which has been documented in this study.