Enteropathogenic (EPEC), Enterotoxigenic Research Articles

Extended-spectrum beta-lactamase-producing strains among diarrhoeagenic Escherichia coli-prospective traveller study with literature review.

BackgroundAntibiotics are no longer the primary approach for treating all travellers’ diarrhoea (TD): most cases resolve without antibiotics and using them predisposes to colonization by multidrug-resistant bacteria. Data are accumulating on increasing resistance among TD pathogens, yet research into the most common agents, diarrhoeagenic Escherichia coli (DEC), remains limited.MethodsA total of 413 travellers to the (sub)tropics were analyzed for travel-acquired diarrhoeal pathogens and ESBL-PE. To identify ESBL-producing DEC, ESBL-producing E. coli (ESBL-EC) isolates were subjected to multiplex qPCR for various DEC pathotypes: enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC) and enterohaemorrhagic (EHEC) E. coli.For a literature review, we screened studies among travellers and locals in low- and middle-income countries (LMICs) on the frequency of ESBL-producing DEC, and among travellers, also DEC with resistance to ciprofloxacin, azithromycin, and rifamycin derivatives.ResultsOur rate of ESBL-EC among all DEC findings was 2.7% (13/475); among EAEC 5.7% (10/175), EPEC 1.1% (2/180), ETEC 1.3% (1/80) and EHEC (0/35) or EIEC 0% (0/5). The literature search yielded three studies reporting ESBL-EC frequency and thirteen exploring resistance to TD antibiotics among travel-acquired DEC. For EAEC and ETEC, the ESBL-EC rates were 10–13% and 14–15%, resistance to fluoroquinolones 0–42% and 0–40%, azithromycin 0–29% and 0–61%, and rifaximin 0% and 0–20%. The highest rates were from the most recent collections. Proportions of ESBL-producing DEC also appear to be increasing among locals in LMICs and even carbapenemase-producing DEC were reported.ConclusionESBL producers are no longer rare among DEC, and the overall resistance to various antibiotics is increasing. The data predict decreasing efficacy of antibiotic treatment, threatening its benefits, for disadvantages still prevail when efficacy is lost.

PATOTIPOS Y RESISTENCIA A ANTIBIÓTICOS DE Escherichia coli EN AGUA RESIDUAL

Water pollution is a serious environmental problem. We analyzed the presence of total fecal coliforms and Escherichia coli , the prevalence of diarrheal pathotypes, and the profiles of antibiotic resistance at different stages. Three composite samples from a wastewater treatment plant (WWTP) in Mexico were analyzed for the presence E. coli with the physical and chemical parameters established in the Mexican Official Standard NOM-001-SEMARNAT-1996. Fifty seven strains were selected from the different stages of the process, and the following pathotypes were determined by multiplex polymerase chain reaction: enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), enteroaggregative (EAEC), enterohemorrhagic (EHEC), and diffuse adherence (DAEC). Their resistance was assessed by the Kirby Bauer method. The results showed a removal efficiency of 95.4% based on the chemical oxygen demand (BOD 5 ). Coliforms and E. coli were found to be higher in the influent. The total frequency of pathotypes was 39 % (22/57) for EIEC, 30 % (17/57) for ETEC, and 15.5 % (9/57) for DAEC and EPEC. Regarding the distribution, 39% of ETEC was detected in the influent, 50% of EIEC before disinfection, 100% of EIEC after disinfection and 43% of ETEC in the effluent.

Phylogenetic Grouping of Human Ocular Escherichia coli Based on Whole-Genome Sequence Analysis.

Escherichia coli is a predominant bacterium in the intestinal tracts of animals. Phylogenetically, strains have been classified into seven phylogroups, A, B1, B2, C, D, E, and F. Pathogenic strains have been categorized into several pathotypes such as Enteropathogenic (EPEC), Enterotoxigenic (ETEC), Enteroinvasive (EIEC), Enteroaggregative (EAEC), Diffusely adherent (DAEC), Uropathogenic (UPEC), Shiga-toxin producing (STEC) or Enterohemorrhagic (EHEC) and Extra-intestinal pathogenic E. coli (ExPEC). E. coli also survives as a commensal on the ocular surface. However, under conditions of trauma and immune-compromised states, E. coli causes conjunctivitis, keratitis, endopthalmitis, dacyrocystitis, etc. The phylogenetic affiliation and the pathotype status of these ocular E. coli strains is not known. For this purpose, the whole-genome sequencing of the 10 ocular E. coli strains was accomplished. Based on whole-genome SNP variation, the ocular E. coli strains were assigned to phylogenetic groups A (two isolates), B2 (seven isolates), and C (one isolate). Furthermore, results indicated that ocular E. coli originated either from feces (enteropathogenic and enterotoxigenic), urine (uropathogenic), or from extra-intestinal sources (extra-intestinal pathogenic). A high concordance was observed between the presence of AMR (Antimicrobial Resistance) genes and antibiotic resistance in the ocular E. coli strains. Furthermore, several virulent genes (fimB to fimI, papB to papX, etc.) and prophages (Enterobacteria phage HK97, Enterobacteria phage P1, Escherichia phage D108 etc.) were unique to ocular E. coli. This is the first report on a whole-genome analysis of ocular E. coli strains.

Isolation, Molecular Characterization and Geoprocessing of Enteropathogenic, Enterotoxigenic, and Shiga Toxin-Producing Escherichia coli in Drinking Water Sources from Southeast Brazil

In Brazil, safe drinking water is not widely available, and consequently waterborne diseases are still associated with high morbidity and mortality rates. Among waterborne bacteria, diarrheagenic Escherichia coli (DEC) should be highlighted. This study targeted the evaluation of enteropathogenic (EPEC), enterotoxigenic (ETEC), and shiga toxin-producing (STEC)/enterohemorrhagic Escherichia coli in drinking water in Southeast Brazil and the georeferencing of generated data. A total of 1185 water samples were studied. Among them 7.8% and 4.1% gave positive results for total and fecal coliforms, respectively. By employing PCR, a total of 12 diarrheagenic E. coli (DEC) isolates (6 ETEC, 4 STEC, and 2 EPEC) from eight water samples (4, 2, and 2 positives for STEC, ETEC, and EPEC, respectively) were detected including samples collected in schools and a healthcare facility where particularly susceptible hosts are found. Data generated were submitted to georeferencing. A positive correlation (r2 = 0.9) between DEC detection and the rainy period was observed. The presence of DEC in drinking water samples in the studied municipalities highlights the relevance of controlling the sources of human and animal fecal pollution, as well as the management of municipal wastewater sources in order to reduce potential risks to human health. Searching for DEC and georeferencing DEC positive sites may subsidize the proposal of corrective and preventive actions by environmental surveillance agencies.

Despite antibiotic treatment of travellers' diarrhoea, pathogens are found in stools from half of travellers at return

Among visitors to the (sub)tropics, 20-50% contract travellers' diarrhoea (TD) and 5-30% take antibiotics. While shortening the duration of illness, antimicrobials predispose to acquisition of multi-drug resistant bacteria. Therefore, liberal use is no longer advocated. Although antibiotics kill pathogens, no data support the view that they could prevent post-infectious sequelae. We investigated how antibiotic use for TD abroad impacts the pathogen findings at return. We revisited 456 travellers' clinical data and stool pathogens examined by qPCR for Salmonella, Yersinia, Campylobacter, Shigella, Vibrio cholerae and enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC) and enteroinvasive (EIEC) Escherichia coli. Among travellers with TD, antibiotic users had pathogen-positive samples less frequently than non-users (50% versus 83%). The difference was significant for EPEC (23% versus 47%) and EAEC (27% versus 54%), but not ETEC (17% versus 26%) or the other pathogens. Shigella/EIEC was found more often among antibiotic users than non-users (4% versus 1%). Despite antibiotic treatment of TD, half of the users still had stool pathogens at return, reflecting either antibiotic resistance of pathogens or recolonisation/reinfection while abroad. Treatment of TD with antibiotics during travel should not be interpreted to indicate eradication of pathogens.

Identification and Characterization of T5-Like Bacteriophages Representing Two Novel Subgroups from Food Products

During recent years, interest in the use of bacteriophages as biocontrol agents against foodborne pathogens has increased, particularly for members of the family Enterobacteriaceae, with pathogenic Escherichia coli, Shigella, and Salmonella strains among them. Here, we report the isolation and characterisation of 12 novel T5-like bacteriophages from confiscated food samples. All bacterophages effectively lysed E. coli K-12 strains and were able to infect pathogenic E. coli strains representing enterohaemorrhagic (EHEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), and enteroinvasive (EIEC) pathotypes, Shigella dysenteriae, S. sonnei strains, as well as multidrug-resistant (MDR) E. coli and multiple strains representing different Salmonella enterica serovars. All the bacteriophages exhibited Siphoviridae morphology. Whole genome sequencing of the novel T5-like bacteriophages showed that they represent two distinct groups, with the genome-based grouping correlating to the different host spectra. As these bacteriophages are of food origin, their stability and lack of any virulence genes, as well as their broad and mutually complementary host spectrum makes these new T5-like bacteriophages valuable candidates for use as biocontrol agents against foodborne pathogenic enterobacteria.

An investigation of vtx2 bacteriophage transduction to different Escherichia coli patho-groups in food matrices and nutrient broth

This study investigated bacteriophage (phage) mediated transfer of the vtx2 gene from a donor Escherichia coli (C600φ3538(Δvtx2::cat)) to enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroaggregative (EAEC), enteroinvasive (EIEC) and diffusely adherent (DAEC) E. coli strains in LB broth, milk, ground beef and lettuce. Two bacterial concentrations for both the E. coli donor and recipient strains, 3 and 5 log10 CFU/ml (LB broth and milk)/g (beef) or/cm2 (lettuce), were used. When transductants were obtained, the location of insertion of the phage (insertion sites wrbA, yehA, sbcB, yecE and/or Z2577) in the E. coli chromosome was investigated by PCR. The vtx2 gene was readily transferred to EAEC O104:H4 (E99518) in all matrices and inserted into the chromosome at the sbcB locus. At higher cell concentrations, transductants were also obtained with ETEC E4683, ETEC E8057 (insertion site unknown) and DAEC O75:H- E66438 (insertion site unknown) in LB broth and milk. It was concluded that the vtx2 gene may be transferred by bacteriophage to different E. coli pathotypes in laboratory and food matrices, resulting in the spread of the vtx2 gene and the emergence of novel foodborne pathogens.

Prospective study of pathogens in asymptomatic travellers and those with diarrhoea: aetiological agents revisited

Travellers' diarrhoea (TD) remains the most frequent health problem encountered by visitors to the (sub)tropics. Traditional stool culture identifies the pathogen in only 15% of cases. Exploiting PCR-based methods, we investigated TD pathogens with a focus on asymptomatic travellers and severity of symptoms. Pre- and post-travel stools of 382 travellers with no history of antibiotic use during travel were analysed with a multiplex quantitative PCR for Salmonella, Yersinia, Campylobacter, Shigella, Vibrio cholerae and five diarrhoeagenic Escherichia coli: enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohaemorrhagic (EHEC) and enteroinvasive (EIEC). The participants were categorized by presence/absence of TD during travel and on return, and by severity of symptoms. A pathogen was indentified in 61% of the asymptomatic travellers, 83% of those with resolved TD, and 83% of those with ongoing TD; 25%, 43% and 53% had multiple pathogens, respectively. EPEC, EAEC, ETEC and Campylobacter associated especially with ongoing TD symptoms. EAEC and EPEC proved more common than ETEC. To conclude, modern methodology challenges our perception of stool pathogens: all pathogens were common both in asymptomatic and symptomatic travellers. TD has a multibacterial nature, but diarrhoeal symptoms mostly associate with EAEC, EPEC, ETEC and Campylobacter.

Detection of major diarrheagenic bacterial pathogens by multiplex PCR panels

Diarrheal diseases remain a major threat to the youngest population in low- and middle-income countries. The main bacterial pathogens causing diarrhea are diarrheagenic Escherichia coli (DEC) that consists of enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohemorrhagic EHEC and enteroinvasive E. coli (EIEC), Salmonella, Shigella spp. (S. dysenteria, S. sonnei, S. flexneri) Campylobacter (C. coli, C. jejuni), Vibrio (V. vulnificus, V. parahaemolyticusm, V. cholerae), Yersinia enterocolitica and Aeromonas hydrophila. The aim of this study was to set up rapid multiplex PCR (mPCR) panels to identify these diarrheagenic pathogens based on their specific virulence genes. Primers against specific target genes were combined into three mPCR panels: one for diarrheal E. coli, one for pathogens causing mainly bloody diarrhea, and the third for the remaining pathogens. The panels were tested against a set of stool samples from Swedish children with diarrhea and controls and the analysis identified bacterial pathogens in 14/54 (26%) of the samples. These results show that our three developed mPCR panels can detect main bacterial diarrheagenic pathogens in clinical samples.

Comparison of Growth Kinetics of Various Pathogenic E. coli on Fresh Perilla Leaf.

Growth kinetics for Escherichia coli O157:H7 in perilla leaves were compared to those of pathogenic E. coli strains, including enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC) and other enterohemorrhagic (EHEC) at 13, 17, 24, 30 and 36 °C. Models for lag time (LT), specific growth rate (SGR) and maximum population density (MPD) as a function of temperature were developed. The performance of the models was quantified using the ratio method and an acceptable prediction zone method. Significant differences in SGR and LT among the strains were observed at all temperatures. Overall, the shortest LT was observed with E. coli O157:H7, followed by EPEC, other EHEC, EIEC and ETEC, while the fastest growth rates were noted in EPEC, followed by E. coli O157:H7, ETEC, other EHEC and EIEC. The models for E. coli O157:H7 in perilla leaves was suitable for use in making predictions for EPEC and other EHEC strains.

Detection of diarrheagenic Escherichia coli strains isolated from dogs and cats in Brazil

Escherichia coli are gut microbiota bacteria that can cause disease in some humans and other animals, including dogs and cats that humans often keep as pets. Diarrheagenic E. coli (DEC) strains are classified into six categories: enteropathogenic (EPEC), enterotoxigenic (ETEC), Shiga toxin-producing (STEC), enteroinvasive (EIEC), enteroaggregative (EAEC), and diffuse-adhering E. coli (DAEC). In this study 144 and 163 E. coli colonies were isolated from the fecal samples of 50 dogs and 50 cats, respectively, with and without diarrhea from a Veterinary Hospital (clinical isolates). The virulence factors were determined using multiplex Polymerase Chain Reaction. Adherence assays, antibacterial susceptibility and serotyping (somatic or flagellar antigens) were performed on DEC isolates. We found 25 (17.4%) and 4 (2.5%) DEC strains isolated from dogs and cats, respectively. Only the EPEC and EAEC pathotypes were found in both animals. Meanwhile, genes from other pathotypes (STEC, EIEC, and ETEC) were not found in these clinical isolates. All of the DEC strains showed mannose-resistant adherence to HEp-2 and HeLa cells, and aggregative adherence was predominant in these isolates. Multiresistant strains to antimicrobials were found in most DEC strains including usual and unusual antimicrobials in veterinary practices. The serotypes of these DEC isolates were variable. The ONT serotype was predominant in these isolates. Some serotypes found in our study were described to human DEC. Here, we demonstrate that pets carry virulent DEC genes, which are mainly strains of EPECs and EAECs. The presence of these virulence factors in isolates from animals without diarrhea suggests that pets can act as a reservoir for human infection.

Prevalence, seasonality and severity of disease caused by pathogenic Escherichia coli in children with diarrhoea in Bolivia

The prevalence of infection caused by different categories of diarrhoeagenic E. coli (DEC) strains, including enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC) and enterohaemorrhagic (EHEC) E. coli, in children who suffered from diarrhoea (n = 3943) or did not have diarrhoea (n = 1026) were analysed in two areas in Bolivia over a period of 4 years. We also analysed the seasonality of DEC infections and severity of diarrhoea in children with DEC infection and compared antibiotic resistance in DEC strains isolated from children with and without diarrhoea. Stool samples were analysed for the presence of DEC by culturing followed by PCR. The most prevalent DEC categories in samples from the children were: EAEC (11.2 %); ETEC (6.6 %); EPEC (5.8 %); and EIEC and EHEC (<1 %). DEC strains were isolated significantly more often from diarrhoea cases (21.6 %) than from controls (17.6 %; P = 0.002). The number of children with diarrhoea associated with EAEC, EPEC and ETEC infections peaked in the Bolivian winter (April-September), although the proportion of DEC-positive stool samples was higher during the warm rainy season (October-March). High levels of antibiotic resistance were detected among the DEC strains. In particular, resistance to tetracycline and sulfamethoxazole-trimethoprim was significantly higher in strains isolated from individuals with diarrhoea than in samples from controls. The severity of disease in children infected with EAEC, EPEC and ETEC varied from mild to severe diarrhoea, although disease severity did not differ significantly between the different DEC categories. ETEC, EPEC and EAEC are commonly found in Bolivia and may cause severe disease in children.

Incidence of diarrhoeagenic Escherichia coli isolated from young children with diarrhoea in the west of Iran

Diarrhoeagenic Escherichia coli (DEC) represents a main group of enteric pathogens that cause human diarrhoea. Because it is not simply distinguished from normal flora by simple laboratory methods, modern molecular diagnostic assays are necessary. Although it is neither necessary nor applicable to perform PCR for all patients, it is of many advantages to verify the prevalence of DEC in different areas by this method. Knowing the prevalence of DEC in an area, we can focus on few pathogens and narrow our antimicrobial treatment. The aim of this study is to evaluate the contribution of the different DEC categories in children diarrhoea in the west of Iran.The stool specimens of 251 children with diarrhoea were collected from June to September 2007. Polymerase chain reaction (PCR) was performed to determine the presence of enteropathogenic (EPEC), enterotoxigenic (ETEC), entero-invasive (EIEC), Shiga toxin-producing (STEC) and entero-aggregative (EAEC) strains. ETEC strains were isolated from 13 and EAEC strains from 16 children. STEC was detected in 7 children, and no EIEC was isolated. Finally, EPEC strains were isolated in 41 cases. EAEC and EPEC are the most frequent DECs in children less than 10 years of age in West of Iran.

Molecular epidemiology ofEscherichia colidiarrhoea in children in Tehran

From July to December 2003, four categories of diarrhoeagenic Escherichia coli were investigated in Tehranian children with acute diarrhoea. Stool specimens of children under 5 years of age with diarrhoea (n=200) and matched controls (n=200) without diarrhoea were studied for the presence of entero-aggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC) and Shiga toxin-producing (STEC) E. coli by PCR identification of six different genes of diarrhoeagenic E. coli. STEC isolates were typed by O157 and H7 antisera. EAEC was the most prevalent category and was found in 24% of patients with diarrhoea and 8% of controls (p<0.0001). ETEC was isolated in 15.5% of patients with diarrhoea but not in any controls ( p<0.0001), STEC in 15% of patients and 2% of controls (p<0.0001) and EPEC in 6% of patients and 5% of controls. Of 30 STEC isolates from patients with diarrhoea, seven were O157:H7 and 23 were non-O157:H7.

EHP001 Formation of microcolonies and biofilms on abiotic surfaces by diarrheagenic Escherichia coli

Escherichia coli are leading causes of diarrhea in children from less developed areas of the world and in travelers from industrialized countries visiting these regions. They are increasingly recognized as pathogens in high income countries, where the mode of transmission is frequently via food and waterborne vehicles. Based on their pathogenic phenotypes and the diseases that they cause, diarrheagenic E. coli have been classified into 6 groups: enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), enteroaggregative (EAEC), diffusely adherent (DAEC), and Shiga toxin producing (STEC) (this last group is also termed enterohemorrhagic (EHEC)). The pathogenic mechanisms by which these groups cause diarrhea are often shared, such as the type 3 secretion system found in EPEC and EHEC, and group-specific, such as the production of Shiga toxins.Although their public health importance is large, the diagnosis of diarrheagenic E. coli in patients and populations is still largely limited to research laboratories. Hence, our knowledge of the spectrum of diseases and syndromes that they cause is quite limited. Also, because we cannot readily identify infected patients, there are many difficulties defining modes of acquisition, prevention and treatment strategies, and estimating the burden of infectious sequelae. These infections pose many challenges, and progress will not occur until we improve our diagnostic capabilities for these agents.

Invasive ability of an Escherichia coli strain isolated from the ileal mucosa of a patient with Crohn's disease.

Crohn's disease (CD) is an inflammatory bowel disease in which Escherichia coli strains have been suspected of being involved. We demonstrated previously that ileal lesions of CD are colonized by E. coli strains able to adhere to intestinal Caco-2 cells but devoid of the virulence genes so far described in the pathogenic E. coli strains involved in gastrointestinal infections. In the present study we compared the invasive ability of one of these strains isolated from an ileal biopsy of a patient with CD, strain LF82, with that of reference enteroinvasive (EIEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteraggregative (EAggEC), enterohemorrhagic (EHEC), and diffusely adhering (DAEC) E. coli strains. Gentamicin protection assays showed that E. coli LF82 was able to efficiently invade HEp-2 cells. Its invasive level was not significantly different from that of EIEC and EPEC strains (P > 0.5) but significantly higher than that of ETEC (P < 0.03), EHEC (P < 0. 005), EAggEC (P < 0.004) and DAEC (P < 0.02) strains. Strain LF82 also demonstrated efficient ability to invade intestinal epithelial cultured Caco-2, Intestine-407, and HCT-8 cells. Electron microscopy examination of infected HEp-2 cells revealed the presence of numerous intracellular bacteria located in vacuoles or free in the host cell cytoplasm. In addition, the interaction of strain LF82 with epithelial cells was associated with the elongation of microvillar extensions that extruded from the host cell membranes and engulfed the bacteria. This internalization mechanism strongly resembles Salmonella- or Shigella-induced macropinocytosis. The use of cytochalasin D and colchicine showed that the uptake of strain LF82 by HEp-2 cells was mediated by both an actin microfilament-dependent mechanism and microtubule involvement. In addition, strain LF82 survived for at least 24 h in HEp-2 and Intestine-407 cells and efficiently replicated intracellularly in HEp-2 cells. PCR and hybridization experiments did not reveal the presence of any of the genetic determinants encoding EIEC, EPEC, or ETEC proteins involved in bacterial invasion. Thus, these findings show that LF82, which colonized the ileal mucosa of a patient with CD, is a true invasive E. coli strain and suggest the existence of a new potentially pathogenic group of E. coli, which we propose be designated adherent-invasive E. coli.

下痢原性大腸菌の紫外線による不活化と光回復

Enteropathogenic(EPEC), enterotoxigenic(ETEC), enterohemorrhagic(EHEC) and enteroinvasive(EIEC) Escherichia coli were investigated for susceptibility to UV radiation at 254nm and photoreactivation. The conclusions obtained in this study can be summarized as follows. 1) The doses of UV light required for 90 and 99 % inactivation of tested pathogenic Escherichia coli ranged from 0.1 to 7.1 mW·sec·cm-2 and from 0.2 to 9.8 mW·sec·cm-2, respectively. 2) Apparent photoreactivation with visible light from a fluorescent lamp was observed in EHEC O26 (FK10), EHEC O26 (FK11), EIEC O124, EIEC O152, EPEC O55. ETEC O6, ETEC O25 (FK20) and ETEC O25 (FK21), but not EHEC O157:H7, EIEC O167, EPEC O44, EPEC O142, EPEC O127 and ETEC O6:H16.

Enteropathogenic and enterotoxigenic Escherichia coli as aetiological factors of infantile diarrhoea in rural and urban Ghana

There are 4 recognized classes of Escherichia coli that cause diarrhoeal disease in humans: enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), and enterohaemorrhagic E. coli (EHEC). Preliminary analysis of enterotoxin production in a rural community in Ghana showed a prevalence of 11·0% LT−ST +, 9·5% LT +ST − and 7·5% EPEC. (LT=heat-labile, and ST=heat-stable, enterotoxin). The results of a similar study in an urban community in Accra, Ghana, showed 10·9% LT −ST +, 5·9% LT +ST −, 1·6% LT +ST + and 6·5% EPEC. 14 different serotypes of EPEC were isolated in the urban area, whereas 6 serotypes and two untypable strains were isolated in the rural area. The most common serotype isolated in Accra was 0126:K71 and that from the rural area was 0128:K67. Serotypes 0143:KXI and 0155:K59 are reported for the first time in Ghana.

Traditional enteropathogenic Escherichia coli of infantile diarrhea.

First described in 1885, Escherichia coli gradually emerged as a cause of infantile diarrhea. Currently, four pathogenic categories of diarrheagenic E. coli are recognized: enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), and enterohemorrhagic (EHEC). Of these, ETEC and EPEC are important causes of pediatric diarrhea, especially in developing countries. ETEC strains are characterized by their production of well-defined heat-labile or heat-stable enterotoxins. In the absence of other identifying characteristics, EPEC strains have been identified by serotyping only; recent laboratory and clinical investigations have shown that these strains constitute a distinctive group of pathogenic microorganisms displaying characteristic adherence to cultured epithelial cells and producing pathognomonic histopathologic changes in experimentally infected animals and naturally infected children. The pathogenicity of most strains of EPEC is associated with the carriage of a 55- to 70-megadalton plasmid that specifies the production of an adherence factor. EPEC strains may also owe their pathogenicity to the production of at least one enterotoxin, possibly a Shiga-like cytotoxin.