Aetiology of diarrhoea and virulence properties of diarrhoeagenic Escherichia coli among patients and healthy subjects in southeast Nigeria

High frequency of antimicrobial resistance in Salmonella and Escherichia coli causing diarrheal diseases at the Yirimadio community health facility, Mali

BACKGROUND

Diarrhoea is a public health problem, especially in developing countries where it is the second leading cause of child mortality. In Low Income Countries like in Mali, self-medication and inappropriate use of antibiotics due to the scarcity of complementary diagnostic systems can lead to the development of multidrug-resistant bacteria causing diarrhoea. The objective of this work was to determine the microorganisms responsible for diarrhoea in children under 15 years of age and to characterize their sensitivity to a panel of antibiotics used in a peri-urban community in Mali. The study involved outpatient children visiting the Yirimadio Community Health Centre and diagnosed with diarrhoea. Stool samples from those patients were collected and analysed by conventional stools culture and the susceptibility to antibiotics of detected bacteria was determined by the disc diffusion method in an agar medium.

RESULT

Overall, 554 patients were included. Children under the age of 3 years accounted for 88.8% (492 of 554) of our study population. Two bacterial species were isolated in this study, Escherichia coli 31.8% (176 of 554) and Salmonella 2.9% (16 of 554). In the 176, E. coli strains resistance to amoxicillin and to cotrimoxazole was seen in 93.8% (165 of 176) and 92.6% ( 163 of 176), respectively. The ESBL resistance phenotype accounted for 39,8% (70 of 176) of E. coli. Sixteen (16) strains of Salmonella were found, of which one strain (6.3%) was resistant to amoxicillin and to amoxicillin + clavulanic acid. Another one was resistant to chloramphenicol (6.3%). Two strains of Salmonella were resistant to cotrimoxazole (12.5%) and two others were resistant to cefoxitin (12.5%).

CONCLUSIONS

The data suggest that E. coli is frequently involved in diarrhoea in children under 3 years of age in this peri-urban setting of Bamako, Mali, with a high rate of resistance to amoxicillin and cotrimoxazole, the most widely used antibiotics in the management of diarrhoea in this setting.

Epidemiology and Risk Factors for Diarrheagenic Escherichia coli Carriage among Children in Northern Ibadan, Nigeria

Diarrhea is a leading cause of childhood morbidity in Africa, but few studies, focus on bacterial diarrheal etiology including multicountry studies that typically excluded Nigeria. We collected stool specimens from 477 children under 5 years of age, 120 with diarrhea, who were enrolled in our prospective case-control study between November 2015 and August 2019. All were attending primary health clinics on the northern outskirts of Ibadan. Up to 10 Escherichia coli isolates were obtained per specimen, and at least three of them were sequenced using Illumina whole-genome sequence technology. Genomes were assembled using SPAdes and evaluated for quality using QUAST. VirulenceFinder was used to identify virulence genes. The microbiological quality of water from 14 wells within the study area was assessed using total and coliform counts. Diarrheagenic E. coli (DEC) were isolated from 79 (65.8%) cases and 217 (60.8%) control children. A number of hybrid DEC pathotypes, Salmonella spp., Yersinia spp., and all DEC pathotypes except Shiga toxin-producing E. coli were detected, but no pathogen showed association with disease (P > 0.05). Enterotoxigenic E. coli were more commonly recovered from children without diarrhea aged below 6 months but exclusively detected in children with diarrhea aged over 9 months. Temporally linked, genetically similar enteroaggregative E. coli were isolated from children in different households in eight instances. No well water sample drawn in the study was potable. Children in northern Ibadan were commonly colonized with DEC. Access to water, proper sanitation, and vaccination against the prevailing pathogens may be critical for protecting children from the less overt consequences of enteric pathogen carriage.

Molecular Characterization of Hetero-Pathogenic and Diarrheagenic Escherichia coli Pathotypes in Diarrheic Children under Five Years and Exposure Environment in Ogun State, South-West Nigeria

BACKGROUND

Diarrheagenic Escherichia coli (DEC) is one of the most common etiological agents of moderate-to-severe diarrhea in Low- and Middle-Income Countries (LMICs). Therefore, determining the source(s) of DEC in index cases and exposure environment is important for developing a prevention strategy. The current study aims to investigate the prevalence of DEC among children under 5 years and their exposure environment in Ogun State, Nigeria.

METHODS

Samples from 228 diarrheic children and their exposure environment were collected and screened for E. coli. Bio-chemically compatible distinct colonies were molecularly characterized using a 7-virulence-gene multiplex PCR with virulence factors (VFs) indicative of four pathotypes of E. coli: enterotoxigenic (ETEC), verotoxigenic (VTEC), enteropathogenic (EPEC), and enteroinvasive (EIEC). Representative pathotypes were subjected to antimicrobial susceptibility and over-expressed efflux pump assays.

RESULTS

One or more VFs typical of specific pathotypes were detected in 25.9% (59/228) diarrhea cases consisting of ETEC (21.5%) and EPEC (0.4%), while hetero-pathogenic pathotypes were found in 4.0% of cases. Of the food sources, 27.9% (101/362) were positive for DEC, of which ETEC accounted for 21.0%, VTEC 1.9%, EPEC 0.6%, EIEC 0.6%, and hetero-pathogenic pathotypes were 3.9%. Furthermore, ETEC was the only pathotype detected in the wastewater (4/183). Interestingly, the consumption of street-vended foods was the most significant (p = 0.04) risk factor for DEC infection in the study area. A total of 73.3% of selected DEC pathotypes showed resistance to antimicrobials, while 27.5% demonstrated over-expression of efflux pump activity.

CONCLUSION

The high prevalence of ETEC across all sources and the occurrence of hetero-pathogenic DEC in diarrheic children and food sources emphasizes the importance of establishing a better strategy for the control and prevention of diarrhea among children in low- and medium-income households.

Prevalence of integrons in multidrug-resistant Escherichia coli isolates from waters and vegetables in Nsukka and Enugu, Southeast Nigeria

Irrigation of fresh produce with poorly treated wastewater or contaminated freshwater sources can lead to produce contamination and foodborne illnesses, as well as the dissemination of antimicrobial resistance determinants. In this study, we assessed the presence of integrons in multidrug-resistant Escherichia coli isolated from the University of Nigeria, Nsukka Wastewater Treatment Plant effluent, tap water, vegetables from irrigated gardens and vegetables sold in selected markets from Nsukka and Enugu cities. E. coli was isolated following standard laboratory procedure and confirmed through beta-glucuronidase (uidA)-targeted polymerase chain reaction (PCR). The antibiotic resistance of the isolates was determined using Bauer-Kirby disk diffusion assay, and multiplex PCR was used to determine the presence of class 1 and 2 integrons. Our result revealed a total of 188 E. coli isolates from WWTP effluent (n = 41), tap water (n = 10) and vegetables from greenhouse (n = 46), farms (n = 55) and market (n = 36). Multidrug resistance was detected in all the isolates, ranging from three-drug resistance in a single isolate to 7-drug resistance patterns in two different isolates. Of the total isolates, class 1 integrons were abundantly detected in 175 (93.1%) and class 2 in 5 (2.7%). All the class 2 integrons were found in isolates that were positive for class 1. The abundance of multidrug-resistant E. coli harbouring class 1 integrons in the effluent and vegetable samples is a potential public health risk. Therefore, the appropriate measures for the safe use of poorly treated wastewater for vegetable farm irrigation are required to be put in place to reduce the microbial load of the discharged effluent. Also, education of farmers and the community on the dangers of wastewater effluent-grown plants and proper methods for cleaning harvested vegetable is recommended.

The first evaluation relationship of integron genes and the multidrug-resistance in class A ESBLs genes in enteropathogenic Escherichia coli strains isolated from children with diarrhea in Southwestern Iran

Enteropathogenic Escherichia coli (EPEC) is one of the most important diarrheagenic agents among infants under 5 years in developing countries. This study aimed to investigate the relationship of integron genes and class A extended-spectrum ESBLs genes in MDR E. coli strains isolated from children with diarrhea in Southwestern Iran. Totally, 321 fecal samples were collected from diarrheal children under 5 years admitted to teaching hospitals of Abadan and Khorramshahr, southwest Iran. Routine bacteriological tests were performed for the identification of E. coli isolates. Multiplex PCR was used for the presence of eae, bfp, stx1, and stx2 genes to detected EPEC strains. Serogrouping was performed for EPEC strains. The EPEC isolates' antibiotic resistance pattern was determined by the disk-diffusion technique. All EPEC isolates were screened for integron and class A β-lactamase genes. Of the 14 EPEC isolates, 12 (85.7%) were found to be ESBL-positive by double disk synergy test (DDST) and PCR. In addition, bla_CTX-M and bla_TEM genes were detected in 83.3% (n = 10) and 58.3% (n = 7) of EPEC isolates, respectively. None of the isolates had the bla_KPC gene. On the other hand, 64.2% (n = 9) and 7.1% (n = 1) were positive only for intlI and intlII genes, respectively. The results demonstrated that EPEC is one of the major causes of childhood diarrhea in our region and that the distribution of class 1 integrons and ESBLs in EPEC strains is highly prevalent. Moreover, the results revealed that continuous monitoring of the emergence and expansion of MDR in EPEC strains is necessary.

The frequency of virulent genes and antimicrobial resistance patterns of diarrheagenic Escherichia coli isolated from stools of children presenting with diarrhea in a tertiary hospital in Abakaliki, Nigeria

Aim: This study was aimed to determine the virulent genes and antibiotic resistance patterns among circulating diarrheagenic Escherichia coli (DEC) pathotypes in a tertiary care health center in east of Nigeria. Materials and Methods: Diarrheal stool samples were obtained from 80 children under 5 years and E. coli was isolated and identified using standard biochemical and molecular methods. Multiplex polymerase chain reaction (PCR) was used to detect eight virulent genes of DEC. Disk diffusion method was used to determine the antibiotic susceptibility of DEC. Results: DEC infection was observed in 54 (68%) children among which ial gene for enteroinvasive E. coli (EIEC) (40% [n=22]) was commonly detected followed by eltA/eltB for enterotoxigenic E. coli (ETEC) (30% [n=16]), pCVD for enteroaggregative E. coli (EAEC) (20% [n=11]), and eaeA/bfpA for typical enteropathogenic E. coli (EPEC) (10% [n=5]). The DEC isolates phenotypically exhibited resistance for ampicillin (AMP) (44 [81%]), followed by ciprofloxacin (CIP)/ levofloxacin (LEV) (28 [52%]), cefoxitin (FOX) (11 [20%]), and amoxicillin-clavulanic acid (AMC) (6 [11%]). About 60% isolates of stable toxins-ETEC were resistant to AMC, CIP, and LEV while all the labile toxin-ETEC exhibited resistance to AMP. About 60% (n=6) resistance were seen in EAEC against ampicillin, AMC, FOX, CIP, and LEV. In EIEC, all the isolates (n=22) were resistant to AMP while 50% (n=11) were resistant to both CIP and LEV. All EPEC (n=5) were resistant to AMP, FOX, CIP, and LEV. Conclusion: High frequency of virulent ial and eltA/eltB genes for EIEC and ETEC, respectively, suggests that they are the primary etiological agents of diarrhea in children among DEC pathotypes. Resistance of DEC to more than two classes of antibiotics indicate possible emergence of multidrug resistance.

Real-time multiplex polymerase chain reaction with high-resolution melting-curve analysis for the diagnosis of enteric infections associated with diarrheagenic Escherichia coli

Introduction

Although diarrheagenic Escherichia coli (DEC) strains are important bacterial causative agents of diarrhoea, they are not routinely sought as stool pathogens in clinical laboratories as conventional microbiological testing are unable to distinguish between normal flora and pathogenic strains of E. coli. This study was undertaken to determine the prevalence of DEC pathotypes amongst children with and without diarrhoea and to detect specific virulent genes present in different DEC pathotypes, using real-time multiplex polymerase chain reaction (PCR) with high-resolution melting (HRM) technology.

Materials and Methods

Stool samples were obtained from cases and controls. Using a set of conventional biochemical tests, E. coli strains were identified. Further, these isolates were subjected to multiplex PCR system for the detection of virulence genes of different pathotypes of DEC. Real-time multiplex PCR was performed for the detection of specific virulent genes of DEC pathotypes, using Rotor-Gene Q instrument (Qiagen) having High-resolution Melt analyser using Type-it HRM PCR kit (Qiagen) containing EvaGreen fluorescent intercalating dye.

Results

In this study, we had successfully standardised two multiplex PCR assays which were found to be effective for direct detection of enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enterotoxigenic E. coli (ETEC) and enteroinvasive E. coli (EIEC). A total of 42 DEC strains were detected at an overall rate of 19.3% (n = 42), from the total 217 E. coli isolates recovered from the cases (n = 39, 17.9%) and control (n = 3, 3.8%) groups. Amongst the 42 DEC pathotypes (39 from cases and 3 from controls), EPEC (10%), EAEC (8.82%), ETEC (2.94%) and EIEC (1.18%) were found in children with diarrhoea (cases) and in children without diarrhoea (control) only EAEC (2.13%) and EPEC (4.26%) were detected. Age distribution, gender variation, seasonal variation and clinical features were also analysed.

Conclusion

This study helped evaluate the prevalence of DEC amongst children (<18 years of age) with and without diarrhoea using multiplex real-time PCR with HRM analysis.

Prevalence and antimicrobial resistance of shiga toxin-producing Escherichia coli and enteropathogenic Escherichia coli isolated from patients with acute diarrhea

BACKGROUND AND OBJECTIVES

Diarrheal disease is still a major health problem in developing countries, where it is considered as one of the leading causes of morbidity and mortality especially in children. Escherichia coli is one of the important enteropathogenic bacteria which causes diarrhea in people. The aim of this study was to investigate the prevalence and antimicrobial resistance of shiga toxin-producing E. coli (STEC), Enterohaemorrhagic E. coli (EHEC), and Enteropathogenic E. coli (EPEC) in fecal samples collected from patients with acute diarrhea in a number of Iranian provinces.

MATERIALS AND METHODS

A total of 102 strains of E. coli were isolated from fecal samples collected from patients with acute diarrhea using microbiological phenotypic tests. The antibiotic susceptibility pattern of all isolates was determined by the disk agar diffusion (DAD) method. The presence of eae, bfp, stx1, sts2 and EAF genes in the isolates was investigated by PCR. The results were analyzed by SPSS; version 17.0 software.

RESULTS

Out of 102 E. coli isolates screened for specific genes, 52 strains of E. coli were identified to harbor STEC 26 (50%), EPEC 13 (25%) and EHEC 13 (25%). Greatest resistance was observed to amoxicillin and ampicillin 40 (76.9%), and most sensitivity to imipenem 52 (100%) and gentamicin 40 (76.9%). We also found that 80.77% of diarrheic E. coli isolates were multidrug resistant (MDR).

CONCLUSION

The results showed that E. coli is one of the major causes of diarrhea and is highly resistant to commonly used antibiotics; therefore, officials must pay great attention to this issue in order to increase the health of the community.

Molecular Characterization of Diarrheagenic Escherichia Coli in Children Less Than 5 Years of Age with Diarrhea in Ouagadougou, Burkina Faso

Diarrheagenic Escherichia coli (DEC) is important bacteria of children’s endemic and epidemic diarrhea worldwide. The aim of this study was to determine the prevalence of DEC isolated from stool samples collected from children with acute diarrhea living in Ouagadougou, Burkina Faso. From August 2013 to October 2015, stool samples were collected from 315 children under 5 years of age suffering from diarrhea in the “Centre Médical avec Antenne Chirurgicale (CMA)” Paul VI and the CMA of Schiphra. E. coli were isolated and identified by standard microbiological methods, and the 16-plex PCR method was used to further characterize them. Four hundred and nineteen (419) E. coli strains were characterized, of which 31 (7.4%) DEC pathotypes were identified and classified in five E. coli pathotypes: 15 enteroaggregative E. coli (EAEC) (48.4%), 8 enteropathogenic E. coli (EPEC) (25.8%) with 4 typical EPEC and 4 atypical EPEC, 4 enteroinvasive E. coli (EIEC) (12.9%), 3 enterohemorrhagic E. coli (EHEC) 9.67%, and 1 enterotoxigenic E. coli (ETEC) 3.2%. The use of multiplex PCR as a routine in clinical laboratory for the detection of DEC would be a useful mean for a rapid management of an acute diarrhea in children.

Lipocalin 2 regulates intestine bacterial survival by interplaying with siderophore in a weaned piglet model of Escherichia coli infection

Iron is an essential nutrient that facilitates cell proliferation and growth, which plays a pivotal role in modulating the battle for survival between mammalian hosts and their pathogens. Pathogenic bacteria secrete siderophores to acquire iron from the host. However, lipocalin 2 (Lcn2), a siderophore-binding antimicrobial protein, binds to siderophores to prevent bacterial uptake of iron, which is critical for the control of systemic infection with Escherichia coli (E. coli). But few studies focus on the anti-infective response of Lcn2 in the intestines by inhibiting bacterial proliferation based on microbial iron metabolism. In this study, we showed that iron was sequestrated within cells in a piglet model of E. coli K88 infection. Siderophores was produced following E. coli K88 infection and siderophore-related genes expression was upregulated in iron-deficiency environment in vitro. Meanwhile, we found that Lcn2 expression was rapidly and robustly induced in jejunum by E. coli K88 infection and could be stimulated by IL-17 and IL-22. Furthermore, both Lcn2 induced in epithelial cells IPEC-1 and added exogenously as a recombinant protein could inhibit the growth of E. coli. We can conclude that Lcn2 is a crucial component of mucosal immune defense against intestinal infection with E. coli K88.

Patterns of Adherence of Helicobacter pylori Clinical Isolates to Epithelial Cells, and its Association with Disease and with Virulence Factors

BACKGROUND AND AIM

Adherence to the gastric epithelium is one of the most important steps of Helicobacter pylori to remain and cause disease. The aim of this study was to analyze whether H. pylori isolates from patients with different gastroduodenal diseases present differences in the pattern of adherence to gastric epithelial cells (AGS), in the ability to induce IL-8, and in the presence of virulence genes.

METHODS

We tested 75 H. pylori strains isolated from nonatrophic gastritis, gastric cancer, and duodenal ulcer patients. The adhesion pattern and IL-8 induction were determined in AGS cells, and invasion of AGS cells was studied using a gentamicin protection assay. The IL-8 levels induced were determined by ELISA.

RESULTS

Helicobacter pylori strains presented diffuse adherence (DA) and localized (LA) adherence patterns, similar to those described for enteropathogenic E. coli (EPEC), were observed in AGS cells. A DA pattern was observed in 57% and LA in 43% of the strains, and DA was more frequent in isolates from patients with gastric cancer (p = 0.044). Strains with a LA pattern induced higher levels of IL-8 (p = 0.042) in AGS cells.

CONCLUSION

The adherence pattern was not associated with neither invasiveness nor with the presence of virulence genes. Our study shows that H. pylori strains present adherence patterns to AGS cells resembling those observed in EPEC and that these patterns may be associated with disease and with activity on AGS cells.

Diarrhoeagenic Escherichia coli in mother-child Pairs in Ile-Ife, South Western Nigeria

Background

Diarrhoeagenic Escherichia coli (DEC) pathotypes are among the most common bacterial causes of morbidity and mortality in young children. These pathogens are not sought routinely and capacity for their detection is limited in Africa. We investigated the distribution and dissemination of DEC in 126 children paired with their mothers in a Nigerian community.

Methods

A total of 861 E. coli were isolated from 126 children with diarrhoea and their mothers. Antimicrobial susceptibility of each isolate was determined by Kirby-Bauer disc diffusion technique. All the isolates were screened for DEC markers by multiplex PCR. Genetic relatedness of DEC strains was determined by flagellin typing and Insertion element 3 (IS3)-based PCR.

Results

DEC were identified from 35.7 % of individuals with the most common pathotype being shiga toxin-producing E. coli (42, 16.7 %). Identical pathotypes were found in 13 (10.3 %) of the mother-child pairs and in three of these strains from mothers and their children showed identical genetic signatures. Over 90 % of DEC isolates were resistant to ampicillin, sulphonamide, tetracycline, streptomycin or trimethoprim, but only 9 (7.2 %) were ciprofloxacin resistant

Conclusion

The data suggest that healthy mothers are asymptomatic reservoirs of multiply-resistant strains that are pathogenic in their children and there are instances in which identical strains are found in mother-child pairs.

Characterization of Shiga-toxin producing E.coli (STEC) and enteropathogenic E.coli (EPEC) using multiplex Real-Time PCR assays for stx1 , stx2 , eaeA

BACKGROUND AND OBJECTIVE

Diarrheal disease is still a major health problem, especially in developing countries, where it is considered as one of the leading causes of morbidity and mortality especially in children. Studies showed that Diarrheagenic E. coli (DEC) such as STES and EPEC strains are among the most prevalent causative agents in acute diarrhea, particularly in children. Aim of the present study was to investigate the presence and the frequency of STEC and EPEC as etiologic agent of diarrhea in children less than 2 years of age with diarrhea in Shiraz.

MATERIALS AND METHODS

A total of 285 stool samples were collected from patients with diarrhea in Shiraz, in 2012. Diarrheagenic E. coli (DEC) strains were isolated by standard biochemical analysis. In this study, we used multiplex Real time PCR and single PCR to detect the presence of indicator genes stx1 , stx2 and eaeA for STEC and EPEC strains, respectively.

RESULTS

A total of 285 stool samples were tested in which 49 (17%) were identified as contaminated with E. coli by biochemical tests. Out of total samples, 15 STEC (31%) and 13 EPEC (27%) were identified using multiplex Real-Time PCR assay. Among STEC isolates, 2 strains were stx1 (+), 8 isolates stx2 (+), 3 isolates were stx1 (+) , stx2 (+) and 2 isolates were stx1 (+) , stx2 (+), eaeA (+).

CONCLUSION

In this study, we found rather high occurrence of STEC and EPEC virulence genes in children with diarrhea. The results of this study showed that, real time PCR can be used as a replacement for conventional PCR assay in the detecting virulence genes of STEC and EPEC strains. Real-time PCR offers the advantage of being a faster, more robust assay, because it does not require post-PCR procedures to detect amplification products.

A study of the prevalence of diarrhoeagenic Escherichia coli in children from Gwagwalada, Federal Capital Territory, Nigeria

Introduction

Diarrhoeagenic Escherichia coli (DEC) are major causes of diarrhoea in Nigeria. This study was conducted to determine the prevalence of diarrhoea caused by DEC within the Federal Capital Territory, Abuja, Nigeria.

Methods

A total of 730 rectal swabs obtained from 201 children with diarrhoea and 529 healthy controls aged 0-24 months were cultured for the isolation of Escherichia coli. All E. coli isolates were investigated by PCR to determine their pathotype.

Results

A total of 61 DEC strains were recovered at a rate of 18.4% and 2.6% from children with diarrhoea and healthy controls respectively. The DEC strains recovered were Enteroaggregative Escherichia coli (34.4%), Shiga-toxin producing Escherichia coli (31.1%), Enterotoxigenic Escherichia coli(18.0%), typical enteropathogenic Escherichia coli (15.0%) and Enteroinvasive Escherichia coli (1.6%). Shiga-toxin producing Escherichia coli andEnteroinvasive Escherichia coli were recovered only from children suffering from diarrhoea and the overall prevalence of DEC strains was significantly higher among the children with diarrhoea (P < 0.0001). The number of DEC strains obtained during the dry season was significantly higher (P = 0.012) than the number obtained in the rainy season.

Conclusion

Diarrhoea caused by E. coli in the Nigerian children studied is associated with several diarrhoeagenic pathotypes and a significant proportion of the healthy children were found to harbour EAEC and ETEC strains. These asymptomatic carriers may be regarded as potential transmitters of infection to vulnerable children in the study area.

Bacterial entropathogens and antimicrobial susceptibility in children with acute diarrhea in Babol, Iran

BACKGROUND

Infectious diarrhea is one of common cause of children diarrhea causing mortality and morbidity worldwide. This study was performed to identify the common bacteria and their antimicrobial susceptibility in children with diarrhea.

METHODS

Children under 14 years old with acute diarrhea who referred to Amirkola Children's Hospital, Mazandaran, North of Iran, were enrolled during the summer and fall of 2009. From each patient, two fecal specimens were collected. Samples were cultured and bacterial isolation was done by conventional methods. Antimicrobial susceptibility was identified by disk diffusion and micro dilution methods.

RESULTS

One hundred-seventy two patients with the mean age of 41.8±37.6 months were evaluated. The bacteria were isolated in 48 (27.9%) cases. The most common isolated bacteria was E.coli and then shigella in both bloody and nonbloody diarrheal patients. There was a significant difference between bacteria positive specimens and WBC in stool smear (p=0.003). All isolated shigella were susceptible to Ceftizoxime and ciprofloxacin and were resistant to Cefixime. Resistant to Nalidixic acid was seen in 14% of them.

CONCLUSION

The results show that E.coli was the most frequently isolated pathogen in children with bloody and nonbloody diarrhea. Ceftizoxime is a good antibiotic for shigellosis in children in our area but Cefixime is not appropriate.

Plesiomonas shigelloides infection in Southeast China

Background

Plesiomonas shigelloides can cause gastroenteritis and extra-intestinal diseases in humans. However, the prevalence of P. shigelloides infections has not been investigated in China.

Methods

Consecutive fecal specimens from outpatients with acute diarrhea and non-diarrheal patients at nine sentinel hospitals in southeast China were collected from March 2010 to May 2012. Bacterial pathogens were detected by culture, and P. shigelloides isolates were subjected to antimicrobial susceptibility testing. We also retrospectively reviewed the hospital microbiology laboratory and infection-control databases for all P. shigelloides isolates identified from 2001–2012 at our institution in addition to data on the patients' clinical and demographic characteristics.

Results

A total of 3,536 outpatients with acute diarrhea were enrolled in the study. P. shigelloides was isolated from 104 (2.9%) patients and accounted for 7.3% of bacterial isolates. Single-pathogen infections with P. shigelloides were present in 76 (73.1%) patients. No strain of P. shigelloides was isolated from the 478 non-diarrheal patients. Based on 444,684 nonfecal specimens, eight patients developed P. shigelloides-related extra-intestinal infections over the 12-year period. All eight patients had underlying diseases, including four with biliary tract diseases and three with liver diseases. Six cases were classified as nosocomial, and five cases were polymicrobial. P. shigelloides was sensitive to most antimicrobial drugs, except ampicillin.

Conclusions

In southeast China, P. shigelloides has significant clinical relevance, although the isolation rate is low.

Prevalence and antibiotic resistance patterns of diarrheagenic Escherichia coli isolated from adolescents and adults in Hamedan, Western Iran

BACKGROUND AND OBJECTIVES

Pathogenic strains of Escherichia coli are a common cause of acute infectious diarrhea. The aim of this study was to investigate the frequency, virulence markers and antibiotic resistance patterns of diarrheagenic E. coli (DEC) isolated from adolescents and adults in Hamadan, west of Iran.

MATERIALS AND METHODS

A total of 187 stool samples were collected from adults with acute diarrhea. Stool culture was performed by conventional methods for enteropathogenic bacteria. Virulence factor genes for DEC were detected by polymerase chain reaction. Antimicrobial susceptibility was tested using the disk diffusion method.

RESULTS

Among the 187 patients, 40 (21.4%) were positive for DEC. The most frequently identified DEC was enteropathogenic E. coli (47.5%), followed by enteroaggregative (20%), enterotoxigenic (17.5%) and shiga-toxin producing E. coli (15%). No isolates of enteroinvasive E. coli were detected. All STEC strains were stx+ / eaeA-. Out of the seven ETEC strains, five (71.4%) produced ST, one (14.3%) produced only LT and one (14.3%) of the isolates produced both ST and LT encoded by est and elt genes, respectively. Among the 40 DEC strains 27(67.5%) were multidrug resistant.

CONCLUSION

DEC contribute to the burden of diarrhea in adults in Hamadan. Enteropathogenic E. coli was the most commonly identified DEC strain in the region studied.

Molecular analysis of typical and atypical enteropathogenic Escherichia coli (EPEC) isolated from children with diarrhoea

Diarrhoea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. To investigate the incidence, antimicrobial resistance and genetic relationships of enteropathogenic Escherichia coli (EPEC) in children with diarrhoea, a total of 612 stool specimens were collected in Tehran, Iran, and cultured to isolate strains of EPEC. The disc diffusion method was used to determine the susceptibility of the isolates according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of eae, stx and bfp-A genes was determined by PCR. The genetic relationships between EPEC isolates were determined by pulsed-field gel electrophoresis (PFGE). Out of the 412 strains of E. coli obtained from 612 diarrhoeal stool specimens, 23 (5.6 %) were identified as EPEC, of which seven (30.4 %) were classified as typical strains of EPEC and 16 (69.6 %) were classified as atypical. Out of the 23 EPEC isolates, 69.5 % were resistant to ampicillin, 39.1 % were resistant to tetracycline and cotrimoxazole, 30.4 % were resistant to cefpodoxime, ceftazidime, ceftriaxone and aztreonam, and 26.1 % were resistant to imipenem. The isolates were classified into 21 pulsotypes by PFGE profiles. The present study shows that typical and atypical EPEC isolates displayed considerable heterogeneity in PFGE profiles and EPEC infections were only sporadic in Tehran. Overall 69 % of isolates were resistant to at least one of the antibiotics tested.

Enteroaggregative Escherichia coli pathotype: a genetically heterogeneous emerging foodborne enteropathogen

Until now, a common feature that defines the enteroaggregative Escherichia coli (EAEC) strains is the ability to produce a 'stacked-brick' appearance on epithelial cells, but it does not distinguish between pathogenic and nonpathogenic strains. Numerous adhesins, toxins, and proteins associated with virulence have been described, as well as multiple factors contributing to EAEC-induced inflammation. None of these factors are found in all EAEC isolates, and no single factor has ever been implicated in EAEC virulence. The European outbreak of Shiga-toxin-producing EAEC raises its pathogenic potential and interest on finding the true pathogenic factors that may define this pathotype. EAEC were first associated with persistent diarrhea in infants from developing countries, since then they have increasingly been linked as a cause of acute and persistent diarrhea in young infants and children in developing and industrialized countries, individuals infected with human immunodeficiency virus, as a cause of acute diarrhea in travelers from industrialized regions, and with foodborne outbreaks. A major effect of EAEC infection is on the malnourished children in developing countries. Here, we will discuss the EAEC public health relevance and their complexity because of the strain heterogeneity regarding their pathogenesis, identification, diagnosis, lineage, epidemiology, and clinical manifestations.

Role of enteropathogenic Escherichia coli in paediatric diarrhoeas in South India

BACKGROUND

Enteropathogenic Escherichia coli(EPEC) is a major cause of diarrhoea in children below 5 years of age. Serotyping is classical method for identification of EPEC strains. But serotypic markers are rarely sufficient to reliably identify the strains as Escherichia coli. Introduction of PCR methodology which depends on detection of virulence factors has provided a practical and rapid way of detecting diarrhoeagenic Esch.coli. Multiantibiotic resistant EPEC strains are a common phenomenon with world wide extension. Moreover for the selection of appropriate therapy of dirrhoeas, knowledge of local antimicrobial therapy pattern plays an important role.

OBJECTIVES

To study the role of EPEC in Paediatric diarrhoea by both Serogrouping and Molecular characterisation by PCR and to analyse the antibiotic susceptabililty patterns of EPEC strains in our area.

MATERIALS AND METHODS

Prospective study of stool samples collected from children with diarrhoea and without diarrhoea who were below 5 years of age was conducted from May to November 2011. Escherichia.coli isolates were identified by Microscopy, Culture and Biochemical reactions. Among the Escherichia coli isolates, EPEC isolates were identified by Serogrouping. Escherichia coli isolates were also subjected to Molecular characterisation by Multiplex PCR assay and those isolates which showed pathogenic genes were futher serotyped. Antibiotic susceptibility pattern of EPEC isolates was determined by CLSI guidelines.

RESULTS

Among the Escherichia coli isolates 36.8% in the diarrhoeal group and none of them from the nondiarrhoeal group were identified as EPEC by serogrouping. 73.3% of the EPEC isolates were below 2 years of age and no much difference in the sex distribution was observed. Mild to moderate dehydration and feccal leuckocytes were seen in 59.9% and 56.6% of isolates respectively. High resistance to Nalidixic acid, Ampicillin, Cotrimoxazole, Ciprofloxacin and Norfloxacin was observed in the diarrhoeal group and resistance to only ampicillin was seen in the nondiarrhoeal group. In the diarrhoeal group 38.8% of Escherichia coli were EAEC and no other diarrhoeagenic Escherichia coli group was found by molecular characterisation. In the nondiarrhoeal Escherichia coli strains, 46.6% showed EAEC genes. EAEC strains in the diarrhoeal group belonged to multiple serotypes, the most common serotype being ONT and in the nondiarrhoeal group, 85.7% were of a single serotype, the most common isolate being O153. Among the Escherichia coli isolates which agglutinated with EPEC polyvalent antisera, 33.3% were positive for Enteroaggregative genes. (Table 1).

CONCLUSION

EPEC is still an important pathogen in paediatric diarrhoeas. O serogrouping can still be relied upon for detection of EPEC. Dehydration is one of the clinical features of EPEC diarrhoea. Fluoroquinolones should only be prescribed in children as second line antibiotics. EAEC are present in classical ' O ' serogroups. Serotype O 153 has an increasing potential for asymptomatic carrier state in children below 5 years of age in our area.

Diarrhoeagenic Escherichia coli detected by 16-plex PCR in children with and without diarrhoea in Burkina Faso

The importance of diarrhoeagenic Escherichia coli (DEC) in Africa is poorly understood, and is unknown in Burkina Faso. This study investigated the occurrence of five major DEC pathogroups in primary cultures of stool samples from 658 Burkinabe children under 5 years old using 16-plex PCR for virulence-associated genes. At least one DEC pathogroup was detected in 45% of 471 children with diarrhoea and in 29% of 187 children without diarrhoea (p <0.001). More than one DEC pathogroup was detected in 11% of children with and 1% of children without diarrhoea (p <0.001). Enteroaggregative E. coli was the most common pathogroup in both children with diarrhoea (26%) and children without diarrhoea (21%). Enteropathogenic E. coli and enterotoxigenic E. coli were detected significantly more often in children with diarrhoea (16% and 13%) than in children without diarrhoea (5% and 4%; p <0.001 for both pathogroups). Shiga toxin-producing E. coli and enteroinvasive E. coli were detected only in children with diarrhoea (2% and 1%, respectively). Diarrhoeagenic E. coli, especially enteropathogenic and enterotoxigenic, may be important, unrecognized causes of childhood diarrhoea in Burkina Faso.

Glutamine supplementation improves intestinal barrier function in a weaned piglet model of Escherichia coli infection

The weaning period is associated with an increased prevalence of gastrointestinal infection in many species. Glutamine (Gln) has been shown to improve intestinal barrier function and immune function in both in vivo and in vitro models. The objective of the present study was to determine the effect of dietary Gln supplementation on intestinal barrier function and intestinal cytokines in a model of Escherichia coli infection. We randomised 21-d-old piglets (n 20) to nutritionally complete isonitrogenous diets with or without Gln (4·4 %, w/w) for 2 weeks. Intestinal loops were isolated from anaesthetised pigs and inoculated with either saline or one of the two E. coli (K88AC or K88 wild-type)-containing solutions. Intestinal tissue was studied for permeability, cytokine expression, fluid secretion and tight-junction protein expression. Animals receiving Gln supplementation had decreased potential difference (PD) and short-circuit current (I(sc)) in E. coli-inoculated intestinal loops (PD 0·628 (SEM 0·151) mV; I(sc) 13·0 (SEM 3·07) μA/cm(2)) compared with control-fed animals (PD 1·36 (SEM 0·227) mV; I(sc) 22·4 (SEM 2·24) μA/cm(2)). Intestinal tissue from control, but not from Gln-supplemented, animals responded to E. coli with a significant increase in mucosal cytokine mRNA (IL-1β, IL-6, transforming growth factor-β and IL-10). Tight-junction protein expression (claudin-1 and occludin) was reduced with exposure to E. coli in control-fed animals and was not influenced in Gln-supplemented piglets. Gln supplementation may be useful in reducing the severity of weaning-related gastrointestinal infections, by reducing the mucosal cytokine response and altering intestinal barrier function.