Search

The canary (Serinus canaria) is appreciated for its beautiful song, colors, and docile temperament and drives a lucrative business. However, diseases caused by avian pathogenic Escherichia coli (APEC) compromise the health of canaries, and the inadequate antimicrobial treatment can lead to the emergence of resistant strains. This study aimed to characterize 21 isolates of E. coli obtained from canaries infected with colibacillosis during an outbreak in northern Paraná State, Brazil. APEC and diarrheagenic E. coli (DEC) virulence genes were screened for by polymerase chain reaction (PCR). All isolates were positive for the hlyF, iss, and ompT genes, which are characteristic of APEC. The iroN gene was found in 95.2% of isolates, and none had the iutA gene. The ipaH gene, characteristic of enteroinvasive E. coli (EIEC), was found in 71.4% of isolates, all belonging to the phylogenetic group B1. High genetic similarity (>95%) was found using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). The isolates belonged to serotypes O117:H4 (71.4%) and O1:H20 (23.8%). This is the first report of a clonal colibacillosis outbreak in canaries caused by APEC. All isolates were resistant to ampicillin, nalidixic acid, ciprofloxacin, enrofloxacin, norfloxacin, and tetracycline. The high rate of multidrug resistance in our study shows the importance of avoiding the inadequate antibiotic treatment. We suggest that further studies should be conducted to contribute to the understanding of colibacillosis in canaries since the health of animals is linked to human and environmental health, as defined by the concept of One Health.

El objetivo fue determinar la frecuencia de contaminación y la diversidad de serotipos de Salmonella enterica (SE) y Escherichia coli (EC) en diferentes etapas de los procesos de matanza y deshuese de bovinos. Se tomaron muestras de heces, canales y cortes primarios (100 de cada tipo) en un rastro Tipo Inspección Federal ubicado en Mexicali, Baja California. EC no se analizó en heces, por ser esta bacteria parte de la microbiota intestinal. La identidad de las cepas se confirmó por métodos bioquímicos y por PCR: genes taxonómicos invA y gadA, para SE y EC, respectivamente. En EC se investigó también la presencia de genes asociados con los principales patotipos. SE tuvo una frecuencia de 34 % en heces, 3 % en canales y 2 % en cortes, siendo Montevideo el serotipo predominante (72.5 % del total de cepas). EC se detectó en canales (34 %) y en cortes (11 %), en concentraciones promedio de 0.012 y 0.33 log UFC cm-2, respectivamente. Aunque varios de los serotipos de EC identificados están asociados con cepas enterotoxigénicas o productoras de toxinas tipo Shiga, ninguno portaba factores de virulencia característicos de estos patotipos. En resumen, las canales y cortes de bovino no son una fuente relevante de cepas patógenas de EC. En contraste, los bovinos constituyen un importante reservorio de SE, lo cual representa un riesgo para la salud pública. Se requieren estudios genómicos sobre el perfil de virulencia y los genes asociados con infecciones subclínicas en cepas de SE provenientes de animales aparentemente sanos

Background/purpose Uropathogenic E. coli (UPEC) is the main cause of urinary tract infection (UTI) and it is known that pregnant women have a higher risk for UTI. UPEC has a variety of virulence and antibiotic resistance factors that facilitate its pathogenic success and it is crucial to know which are the susceptibility patterns, Extended-Spectrum-β-Lactamase (ESBL) production, virulence genes, pathogenicity islands (PAI), phylogenetic groups and serotypes among strains isolated from pregnant and non-pregnant women. Methods One hundred fifty UPEC strains were isolated from pregnant and non-pregnant women from two different Mexican states (Sonora and Puebla). Strains were analyzed using the Kirby-Bauer method for the determination of antibiotic susceptibility and ESBL. Virulence genes, PAIs and phylogenetic groups were determined using a multiplex PCR. Strains were serotyped by an agglutination assay. Blood agar and CAS agar were used for phenotypic assays. Results 92.7% of UPEC strains showed multidrug-resistant (MDR), 6.7% extremely-resistant (XDR) and 0.6% pandrug-resistant (PDR). The highest resistance was determined to be for β-lactam antibiotics (>72% in both states) and 44.5% of the UPEC strains were ESBL+. The predominant virulence genes found were fimH (100%), iucD (85%) and iha (60%). The strains isolated from pregnant women from Puebla presented a large percentage of genes associated with upper urinary tract infections. PAIs were found in 51% and 68% of the strains from Sonora and Puebla, respectively. All the strains were siderophores producers and 41.5% produced hemolysis. The serotypes found were diverse and belonged to phylogroups A, B2 and C. Conclusion The UPEC strains from this study are MDR with tendency to XDR or PDR, they can cause upper UTIs and are serotypically and phylogenetically diverse, which supports the need to develop new strategies for UTI treatment in pregnant and non-pregnant Mexican women.

E. coli es una bacteria muy versátil, es un patógeno causante de diarreas, y una característica básica de este tipo de patógenos, es la presencia de los factores que le permiten su persistencia en el ambiente externo. Al ser E. coli un habitante del intestino de mamíferos, esta bacteria ha adquirido mecanismos para vivir en ambos ambientes: en el exterior y en el interior de un hospedero. El objetivo principal del estudio fue describir los distintos serotipos de E. coli en cepas de un estudio anterior que provenían de niños menores de 3 años con un cuadro diarreico. Se describieron 55 serotipos distintos en 86 cepas de E. coli provenientes de deposiciones de niños menores de 3 años que fueron casos de diarrea. Este es el primer estudio que describe serotipos tan variados de E. coli de origen humano. Los serotipos encontrados concuerdan mucho con los estudios conjuntos realizados en cepas ambientales de E. coli de origen hídrico y alimentos. Además de aportar al conocimiento sobre este patógeno, la importancia de esta información es el hecho de saber que serotipos podrían estar causando las diarreas infantiles.

Un estudio publicado en el año 2016 por parte de la escuela de Biología sobre la variación espacial y temporal de la diversidad y abundancia del fitoplancton del Lago de Yojoa en un año hidrológico 2014-2015 tuvo una parte alterna donde se evaluó la calidad microbiológica de las muestras de agua obtenidas del mismo. Los análisis de agua confirmaron la presencia de coliformes fecales con crecimiento a 44°C. El objetivo principal fue clasificar molecularmente los patotipos y grupos filogenéticos de E. coli de cepas obtenidas a partir de muestras de fuentes de agua. Adicionalmente se logró la clasificación de las cepas en serotipos lo cual brindo más información y coincidencias epidemiológicas con otros estudios de otras fuentes. El estudio comprendió el año 2016 donde se realizó toda la parte experimental y 2017 se concluyó el análisis de todos los datos obtenidos. Un total de 32 cepas fueron analizadas. El 47 % (n=15) fueron cepas obtenidas de un estudio de aguas en Francisco Morazán (se unieron al estudio debido a su origen hídrico). El 53 %(n=17) corresponde a las cepas obtenidas del Lago de Yojoa. La filogenia de estas cepas es variada ya que se lograron ubicar en 7 de 8 grupos filogenéticos de los cuales se puede discriminar mediante la técnica utilizada. Del total de cepas analizadas un 75 % (n=24) amplificó para distintos factores de virulencia. El 50 % (n=16) lo representa las cepas originarias del Lago de Yojoa y el 25 % (n=8) las cepas de Francisco Morazán. El 63 % (n=15) corresponde al patotipo EPEC, el cual se divide de la siguiente manera: 17 % (n=4) corresponde a EPEC atípicas y el 46 % (n=11) a EPEC típicas. Existen serotipos comunes en ambas fuentes hídricas además de cepas productoras de toxinas. La existencia de un patotipo enteroagregativo de E. coli que por primera vez se registra en Honduras y tiene la capacidad de la creación de biofilms en superficies acuáticas. La existencia de cepas que albergan factores de virulencia en ambientes acuáticos es un hecho que puede ser un potencial problema de salud pública en aquellas poblaciones vulnerables y expuestas a estas fuentes hídricas. Se debe indagar más acerca del hecho que estas cepas son o no potenciales patógenos para el humano o benéficos para el ambiente y nicho ecológico en el que se encuentran.

A presença de microrganismos patogênicos em produtos cárneos pode levar a doenças de origem alimentar e perdas econômicas aos seus produtores. Pequenas indústrias da região de Londrina, Paraná, produzem embutidos que são comercializados em feiras livres, pequenos mercados, bares e restaurantes da cidade. Embora essas indústrias sejam fiscalizadas pelo Serviço de Inspeção Municipal de Londrina, não existem dados sobre microrganismos patogênicos presentes nesses produtos. Os objetivos deste estudo foram pesquisar a presença de Salmonella spp. em amostras de linguiças produzidas e comercializadas na região de Londrina, Paraná, e identificar os genes de virulência eae, bfp, stx1, stx2, hlyA, ipaH, elt, est, aggR, aap e AA probe das cepas de E. coli isoladas dessas amostras. Quarenta e seis amostras de três tipos de linguiça (suína fresca, toscana e calabresa) produzidas por quatro diferentes produtores (marcas A, B, C e D) foram analisadas. Salmonella spp. foi isolada em 13 (28.3%) amostras e E. coli em 33 (71.3%) amostras. Das 13 amostras contaminadas com Salmonella spp., sete (53.8%) foram da marca A. A contaminação por Salmonella spp. foi maior nas amostras de linguiça toscana (8/17 – 41.7%) quando comparada com a contaminação encontrada nas amostras de linguiça suína (4/22 – 18.2%), independente da marca analisada. E. coli foi isolada de 12 das 13 amostras contaminadas com Salmonella spp. Uma amostra de linguiça calabresa estava contaminada com E. coli enteropatogênica clássica atípica do sorotipo O108:H9, que apresentava genes eae e hlyA. Os resultados obtidos sugerem contaminação da planta de processamento e ou das matérias primas utilizadas na fabricação das linguiças. Uma fiscalização mais adequada das indústrias se torna necessária para que as Boas Práticas de Fabricação sejam atendidas e, consequentemente, prevenida a contaminação do produto por bactérias patogênicas.

Healthy lambs are one of the major reservoirs of Shiga toxin-producing Escherichia coli (STEC) and it is known as the cause of foodborne diseases (FBD). The work objective is to characterize (STEC) isolates obtained from rectal swabs of healthy lambs herds, a total of 183 samples were obtained from sheep production units of the State of Mexico. E. coli isolates were confirmed through the amplification of the uid A gene. antimicrobial sensitivity pattern was determined through Kirby-Bauer ( CLSI, 2012 ) test and the presence stx1, stx2 and eae genes from isolates by multiplex PCR. Serotyping was performed using specific anti-O and anti-H sera (SERUNAM, Mexico) for 185 Somatic and 56 flagellar antigens. 126 isolates biochemically and molecularly identified as E. coli were obtained, of which 80 did not express any virulence factor and 46 expressed at least some (STEC) virulence factor. The highest percentage of E. coli resistance was for tetracycline 48.7% (39/80), followed by nalidixic acid 13.7% (11/80), gentamicin 6.2% (5/80) and Ciprofloxacin 3.7% (3/80). Resistance to amikacin, cefotaxime and ceftazidime were not detected. A frequency of 46 STEC isolates (36.2%) were obtained, of which 28/46 (22.0%) expressed stx1, stx2 3/46 (6.5%), stx1, stx2 13/46 (10.2%) and eae 2/46 (1.6%). Thirty different serotypes were obtained. The three serotypes with the highest number of isolates (four each) were: O76:H19, O118:H27 and O146:H21 which have been identified as a cause of diarrhea in human population. An isolate of serogroup O104 was obtained, with a significant importance for European public health. In virtue of the discovered serotypes and the virulence factors distribution, we can affirm that the obtained isolates from lambs in the State of Mexico are classifiable as atypical STEC of low virulence.

Introduction: Antimicrobial resistance in Escherichia coli, one of the causal agents of aerobic vaginitis, leads to the persistence of the infection. The investigation of integrons acquires relevance, since they are elements that are responsible for the acquisition of resistance to antibiotics. The aim of this work was to describe the structural diversity of class 1 integrons in virulent and commensal strains of E. coli isolated from patients with vaginal infection. Methodology: Ninety-two strains of E. coli were isolated from patients with aerobic vaginitis. Resistance profile against 19 antibiotics and class 1 integrons were detected by PCR. The identity and arrangement of cassettes was determined by sequencing. ERIC-PCR assays were carried out in strains with identical arrays. Finally, genotyping by Clermont algorithm and serotyping were performed. Seventeen strains showed integrons located in plasmids. Results: Ten different gene cassette arrays were identified in 30 strains of E. coli. Cassettes corresponding to genes coding for adenylyltransferases (aadA), dihydrofolate reductases (dfrA), and oxacillinases (blaOXA) were detected. Array dfrA17-aadA5 was predominantly prevalent over the other arrays identified. Phylogenetic group A was the most predominant, followed by group B2 and D. Conclusions: This study demonstrates the presence of E. coli of vaginal origin carrying class 1 integrons, which are main genetic elements of capture of resistance genes, with the possibility of capturing new resistance cassettes. These evidences should serve for the modification of protocols in the diagnosis and treatment of aerobic vaginitis, and the development of policies for the rational use of antimicrobials.

Escherichia coli strains are part of the normal biota of humans and animals; however, several clinical reports have implicated E. coli as the etiological agent of diarrhea in humans and companion animals. Thus, the aim of the present study was to know if companion dogs in the city of San Luis Potosi are colonized with virulent potentially harmful E. coli strains. Rectal swabs from 30 dogs, 13 with and 17 without diarrhea were analyzed. Phylogenetic and virulence genes analysis was performed to the E. coli isolates. Additionally, the Kirby-Bauer test was used to analyze the sensitivity to 32 different antimicrobials from 14 families. Eighty-five isolates were identified as E. coli and detected in 97% of healthy and diarrheic dog samples. E. coli isolates from healthy dogs carried several virulence genes, in contrast with those from diarrheic animals that presented only eaeA. In healthy dogs, phylogenetic analysis showed that 57% and 43% of E. coli isolates belonged to commensal (A and B1) and virulent (B2 and D) groups respectively. Meanwhile, diarrheic dogs showed that 69% of the isolates were identified as virulent B2 and D phylogroups. Moreover, E. coli resistant to β-lactams, aminoglycosides, tetracycline, quinolones, and folate inhibitors were detected in both groups of dogs. The presence of E. coli with eaeA virulence gene in diarrheic dogs, suggest that these strains are associated with the animal´s condition. Finally, major attention must be drawn to the careful handling of dogs because of their capability to harbor and disseminate virulent E. coli strains.

The O25-ST131 clone was identified within 169 uropathogenic Escherichia coli (UPEC) strains. The 44.8% of the 29 O25-ST131 clones detected were positive to least to one extended-spectrum β-lactamase gene. The phylogroup D was mainly found. The O25-ST131 clone appeared to be associated with community-acquired UTI in Mexico City.

Introduction: Uropathogenic Escherichia coli (UPEC) are the main etiological agent of urinary tract infections (UTIs). Association between different serotypes and UTIs is known, however, some strains are incapable to be serotyped. The aim of this work was to study bthe phenotypical and genotypical characteristics of 113 non-typeable (NT) and auto-agglutinating (AA) E. coli strains, isolated from UTIs in children and adults. Methodology: The 113 UPEC strains were analyzed by PCR assays using specific primers to determine their serogroups, fimH, papC, iutA, sat, hlyCA and cnf1, virulence associated genes, and chuA, yjaA and TSPE4.C2 for phylogroup determination. Additionally, the diffusion disk method was performed to evaluate the antimicrobial resistance to 18 antimicrobial agents. Results: Using the PCR assay, 63% (71) of the strains were genotyped showing O25 and O75 as the most common serogroups. The virulence genes fimH (86%) and iutA (74%) were the most prevalent, in relation to the phylogroups the commensal (A and B1) and virulent (B2 and D) showed similar frequencies (P > 0.05). The antimicrobial susceptibility test showed a high percentage (73%) of multidrug-resistant strains. Conclusions: The genotyping allowed identifying the serogroup in many of the strains that could not be typed by traditional serology. The strains carried virulence genes and were multidrug-resistant in both, commensal and virulent phylogroups. Our findings revealed that, in addition to the classical UPEC serogroups, there are pathogenic serogroups not reported yet.

The presence of pathogenic microorganisms in meat products may result in foodborne diseases and economic losses to their producers. Small industries in the region of Londrina, Paraná, produce sausages that are commercialized in free fairs, small markets, bars, and restaurants in the city. Although these industries are inspected by the Municipal Inspection Service of Londrina, there are no data about the pathogenic microorganisms present in these products. The objective of this study was to investigate the presence of Salmonella spp. in sausages produced and sold in the region of Londrina, Paraná, and identify eae, bfp, stx1, stx2, hlyA, ipaH, elt, est, aggR, aap, and AA probe genes in Escherichia coli strains isolated from these samples. Forty-six samples of three types of sausages (fresh pork, Tuscan, and Calabresa) produced by four different producers (brands A, B, C, and D) were analyzed. Salmonella spp. was isolated from 13 (28.3%) and E. coli from 33 (71.3%) of the analyzed samples. Seven (53.8%) of 13 samples contaminated with Salmonella spp. were from brand A. Salmonella spp. contamination was the highest in the Tuscan sausage samples (8/17, 41.7%) when compared with the fresh pork sausage samples of all brands analyzed. E. coli was isolated from 12 of 13 samples contaminated with Salmonella spp. One sample of Calabresa sausage was contaminated with atypical enteropathogenic E. coli serotype O108:H9 that has the eae and hlyA genes. The results suggest contamination of the processing plant and/or raw meat used in the manufacture of sausages. A better inspection of the industries is required to ensure that Good Manufacturing Practices are followed by which the contamination of products by pathogenic bacteria can be prevented. A presença de microrganismos patogênicos em produtos cárneos pode levar a doenças de origem alimentar e perdas econômicas aos seus produtores. Pequenas indústrias da região de Londrina, Paraná, produzem embutidos que são comercializados em feiras livres, pequenos mercados, bares e restaurantes da cidade. Embora essas indústrias sejam fiscalizadas pelo Serviço de Inspeção Municipal de Londrina, não existem dados sobre microrganismos patogênicos presentes nesses produtos. Os objetivos deste estudo foram pesquisar a presença de Salmonella spp. em amostras de linguiças produzidas e comercializadas na região de Londrina, Paraná, e identificar os genes de virulência eae, bfp, stx1, stx2, hlyA, ipaH, elt, est, aggR, aap e AA probe das cepas de E. coli isoladas dessas amostras. Quarenta e seis amostras de três tipos de linguiça (suína fresca, toscana e calabresa) produzidas por quatro diferentes produtores (marcas A, B, C e D) foram analisadas. Salmonella spp. foi isolada em 13 (28.3%) amostras e E. coli em 33 (71.3%) amostras. Das 13 amostras contaminadas com Salmonella spp., sete (53.8%) foram da marca A. A contaminação por Salmonella spp. foi maior nas amostras de linguiça toscana (8/17 – 41.7%) quando comparada com a contaminação encontrada nas amostras de linguiça suína (4/22 – 18.2%), independente da marca analisada. E. coli foi isolada de 12 das 13 amostras contaminadas com Salmonella spp. Uma amostra de linguiça calabresa estava contaminada com E. coli enteropatogênica clássica atípica do sorotipo O108:H9, que apresentava genes eae e hlyA. Os resultados obtidos sugerem contaminação da planta de processamento e ou das matérias primas utilizadas na fabricação das linguiças. Uma fiscalização mais adequada das indústrias se torna necessária para que as Boas Práticas de Fabricação sejam atendidas e, consequentemente, prevenida a contaminação do produto por bactérias patogênicas.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of bacterial diarrheal illness, affecting practically every population worldwide, and was estimated to cause 120,800 deaths in 2010. Here, we report the genome sequence of ETEC strain FMU073332, isolated from a 25-month-old girl from Tlaltizapán, Morelos, México.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of bacterial diarrheal illness, affecting practically every population worldwide, and was estimated to cause 120,800 deaths in 2010. Here, we report the genome sequence of ETEC strain FMU073332, isolated from a 25-month-old girl from Tlaltizapán, Morelos, México.

Nosocomial infections are a major cause of morbidity and mortality among neonates admitted to neonatal intensive care units (NICUs). The aim of this paper was to describe an outbreak of Escherichia coli among infants admitted to the NICU of the General Hospital "Dr. Manuel Gea Gonzalez" in May of 2008. The isolated E. coli strains were identified using standard biochemical methods. The susceptibilities of these strains were analysed by determining their minimal inhibitory concentrations. Following this, their molecular relationships to each other were assessed by pulsed field gel electrophoresis (PFGE) analysis and corroborated by serology. Twelve E. coli strains were isolated from blood, urine, or indwelling catheter samples from five cases of preterm infants within a 3-day period. Patients were admitted to the NICU of the general hospital and, during the outbreak, developed sepsis caused by E. coli. For four of the patients, the average age was 23 days, while one patient was a 3-month-old infant. Prior to sepsis, the infants had received assisted ventilation and hyperalimentation through a central venous catheter. Two profiles were observed by PFGE; profile A was identified as the outbreak's cause and an outcome of cross-infection, while profile B showed genetic differences but serologically it was identified as part of the same serotype. We conclude that E. coli colonised the patients through horizontal transmission. A focal source of the microorganism in this outbreak was not identified, but cross-transmission through handling was the most probable route.

Background Epidemics and pandemics of cholera, a diarrheal disease, are attributed to Vibrio cholerae serogroups O1 and O139. In recent years, specific lytic phages of V. cholerae have been proposed to be important factors in the cyclic occurrence of cholera in endemic areas. However, the role and potential participation of lytic phages during long interepidemic periods of cholera in non-endemic regions have not yet been described. The purpose of this study was to isolate and characterize specific lytic phages of V. cholerae O1 strains. Methods Sixteen phages were isolated from wastewater samples collected at the Endhó Dam in Hidalgo State, Mexico, concentrated with PEG/NaCl, and purified by density gradient. The lytic activity of the purified phages was tested using different V. cholerae O1 and O139 strains. Phage morphology was visualized by transmission electron microscopy (TEM), and phage genome sequencing was performed using the Genome Analyzer IIx System. Genome assembly and bioinformatics analysis were performed using a set of high-throughput programs. Phage structural proteins were analyzed by mass spectrometry. Results Sixteen phages with lytic and lysogenic activity were isolated; only phage ØVC8 showed specific lytic activity against V. cholerae O1 strains. TEM images of ØVC8 revealed a phage with a short tail and an isometric head. The ØVC8 genome comprises linear double-stranded DNA of 39,422 bp with 50.8 % G + C. Of the 48 annotated ORFs, 16 exhibit homology with sequences of known function and several conserved domains. Bioinformatics analysis showed multiple conserved domains, including an Ig domain, suggesting that ØVC8 might adhere to different mucus substrates such as the human intestinal epithelium. The results suggest that ØVC8 genome utilize the “single-stranded cohesive ends” packaging strategy of the lambda-like group. The two structural proteins sequenced and analyzed are proteins of known function. Conclusions ØVC8 is a lytic phage with specific activity against V. cholerae O1 strains and is grouped as a member of the VP2-like phage subfamily. The encoding of an Ig domain by ØVC8 makes this phage a good candidate for use in phage therapy and an alternative tool for monitoring V. cholerae populations. Electronic supplementary material The online version of this article (doi:10.1186/s12985-016-0490-x) contains supplementary material, which is available to authorized users.

Enteropathogenic Escherichia coli (EPEC) produces a characteristic attaching and effacing (A/E) lesion in the small intestines of infected children. The immune response to EPEC infection remains poorly characterized. The molecular targets that elicit protective immunity against EPEC disease are unknown. In this study protein antigens from EPEC were identified using secretory immunoglobulin A (sIgA) antibodies isolated from milk from Mexican women by Western blot analysis. Purified sIgA antibodies, which inhibit the adherence of EPEC to cells, reacted to many EPEC proteins, the most prominent of which were intimin (a 94-kDa outer membrane protein) and two unknown proteins with apparent molecular masses of 80 and 70 kDa. A culture supernatant protein of 110 kDa also reacted strongly with the sIgA antibodies. The molecular size of this protein and its reactivity with specific anti-EspC antiserum suggest that it is EPEC-secreted protein C (EspC). These EPEC surface protein antigens were consistently recognized by all the different sIgA samples obtained from 15 women. Screening of clinical isolates of various O serogroups from cases of severe infantile diarrhea revealed that all EPEC strains able to produce the A/E lesion showed expression of intimin and the 80- and 70-kDa proteins. Such proteins reacted strongly with the purified sIgA pool. Moreover, nonvirulent E. coli strains were unable to generate a sIgA response. The immunogenic capacities of the 80- and 70-kDa proteins as virulence antigens have not been previously reported. The strong sIgA response to intimin and the 80- and 70-kDa proteins obtained in this study indicates that such antigens stimulate intestinal immune responses and may elicit protective immunity against EPEC disease.

The presence of Vibrio cholerae non-O1 in water supplies for human consumption in the city of Campeche and rural locality of Becal was investigated. V. cholerae non-O1 was detected in 5.9% of the samples obtained in deep pools of Campeche. Studies conducted in Becal and neighbourhood of Morelos in Campeche indicated that collected samples harbored V. cholerae non-O1 in 31.5% and 8.7% respectively. There was a particular pattern of distribution of V. cholerae non-O1 serotypes among different studied regions. Accordingly, V. cholerae non-O1 serotype O14 predominated in the deep pools of Campeche and together with V. cholerae non-O1, O155 were preferentially founds in samples taken from intradomiciliary faucets in the neighbourhood of Morelos. Samples from Becal predominantly presented the serotype O112. 60% and 53.8% of all studied strains of V. cholerae non-O1 proved to be resistant to ampicillin and carbenicillin. 3.1%, 7.7% and 6.2% presented resistant to doxycycline, trimethoprim-sulfamethoxazole and erythromycin respectively. The study showed the necessity of performing a strong epidemiologic surveillance for emergence and distribution of V. cholerae non-O1.