Molecular mechanisms of multidrug resistance in clinically relevant enteropathogenic bacteria (Review).

Multidrug resistant (MDR) enteropathogenic bacteria are a growing problem within the clinical environment due to their acquired tolerance to a wide range of antibiotics, thus causing severe illnesses and a tremendous economic impact in the healthcare sector. Due to its difficult treatment, knowledge and understanding of the molecular mechanisms that confer this resistance are needed. The aim of the present review is to describe the mechanisms of antibiotic resistance from a genomic perspective observed in bacteria, including naturally acquired resistance. The present review also discusses common pharmacological and alternative treatments used in cases of infection caused by MDR bacteria, thus covering necessary information for the development of novel antimicrobials and adjuvant molecules inhibiting bacterial proliferation.

Detection of Salmonella spp. and diarrheagenic Escherichia coli in fresh pork sausages / Pesquisa de Salmonella spp. e Escherichia coli diarreiogênica em linguiças suínas frescas

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.(AU)

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.(AU)

Detection of Salmonella spp. and diarrheagenic Escherichia coli in fresh pork sausages / Pesquisa de Salmonella spp. e Escherichia coli diarreiogênica em linguiças suínas frescas

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.

Impact of urban contamination of the La Paz River basin on thermotolerant coliform density and occurrence of multiple antibiotic resistant enteric pathogens in river water, irrigated soil and fresh vegetables.

La Paz River in Andean highlands is heavily polluted with urban run-off and further contaminates agricultural lowlands and downstream waters at the Amazon watershed. Agricultural produce at this region is the main source of vegetables for the major Andean cities of La Paz and El Alto. We conducted a 1 year study, to evaluate microbial quality parameters and occurrence of multiple enteropathogenic bacteria (Enterohemorrhagic E. coli-EHEC, Enteroinvasive E. coli or Shigella-EIEC/Shigella, Enteroaggregative E. coli-EAEC, Enteropathogenic E. coli-EPEC Enterotoxigenic E. coli-ETEC and Salmonella) and its resistance to 11 antibiotics. Four sampling locations were selected: a fresh mountain water reservoir (un-impacted, site 1) and downstream sites receiving wastewater discharges (impacted, sites 2-4). River water (sites 1-4, N = 48), and soil and vegetable samples (site 3, N = 24) were collected during dry (April-September) and rainy seasons (October-March). Throughout the study, thermotolerant coliform density values at impacted sites greatly exceeded the guidelines for recreational and agricultural water uses. Seasonal differences were found for thermotolerant coliform density during dry season in water samples nearby a populated and hospital compound area. In contrast to the un-impacted site, where none of the tested enteropathogens were found, 100 % of surface water, 83 % of soil and 67 % of vegetable samples at impacted sites, were contaminated with at least one enteropathogen, being ETEC and Salmonella the most frequently found. ETEC isolates displayed different patterns of toxin genes among sites. The occurrence of enteropathogens was associated with the thermotolerant coliform density. At impacted sites, multiple enteropathogens were frequently found during rainy season. Among isolated enteropathogens, 50 % were resistant to at least two antibiotics, with resistance to ampicillin, nalidixic acid, trimethoprim-sulfamethoxazole and tetracycline commonly present. Moreover, some Salmonella isolates were distinguished by their multi-resistance to ≥8 antibiotics, within soil and vegetable samples. Overall, this study demonstrates that La Paz River-an affluent of the Amazon macrobasin-is heavily polluted along the year with a high density of thermotolerant coliforms and is a reservoir of multiple antibiotic resistant enteropathogens, present in river water, soil and vegetables. These data highlight health risk associated with food and waterborne diseases at the region.

Actividad bacteriostática y bactericida de la tintura de propóleos sobre bacterias enteropatógenas / Bacteriostatic and bactericidal activity of propolis tincture on enteropathogenic bacteria

El propóleos es una sustancia resinosa que las abejas Apis mellífera adultas producen para garantizar la total asepsia de la colmena. Otras especies de abejas también producen propóleos. Con el objeto de evaluar la actividad bacteriostática y bactericida in vitro de la tintura etanólica de propóleos comercial al 70 % v/v proveniente de un apiario del Estado Cojedes, Venezuela sobre bacterias enteropatógenas ATCC. Se utilizaron Salmonella entérica subsp entérica serotipo paratyphi A, Salmonella entérica subsp entérica serotipo paratyphi B Salmonella entérica subsp entérica serotipo typhi, Shigella sonnei, Shigella flexneri, Yersinia enterocolitica y Escherichia coli enterohemorrágica (O157:H7). Las cepas mencionadas se expusieron a distintas concentraciones de tintura de propóleos durante 24 horas para determinar la Concentración Mínima Inhibitoria (CMI) y la Concentración Mínima Bactericida (CMB) utilizando el método de macrodilución en tubos. Resultados: Salmonella paratyphi A fue la única bacteria con efecto inhibitorio total en agar BHI. En las demás bacterias se evidenció efecto bacteriostático parcial. Yersinia enterocolítica fue la más sensible con una CMI 4% y CMB 8 %, seguida por Shigella sonnei, Salmonella paratyphi B, Salmonella typhi y Escherichia coli (O157:H7), con CMI 8% Y CMB 11% y finalmente Shigella flexneri y Salmonella paratyphi A fueron las más resistente con CMI 11% y CMB 15%. Se demostró que la tintura de propóleos tiene efecto bacteriostático y bactericida in vitro en las cepas estudiadas y que el etanol presente como solvente no es el responsable de tal efecto.

Propolis is a resinous substance produced by adult bees Apis mellífera to ensure complete asepsis of the hive. Other species of bees also produce propolis. The aim of this study was to assess the bacteriostatic and bactericidal activity in vitro of commercial ethanolic tincture of propolis 70% v/v from an apiary in Cojedes State, Venezuela on enteropathogenic bacteria ATCC. Used Salmonella enterica subsp enterica suptype paratyphi A, Salmonella enterica subsp enterica suptype paratyphi B, Salmonella enterica subsp enterica subtype typhi, Shigella sonnei, Shigella flexneri, Yersínia enterocolitica, and Escherichia coli (O157:H7). The strains mentioned were exposed to different concentrations of propolis for 24 hours to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the macrodilution method in tubes. Results: S. paratyphi A was the only bacterium with a total inhibitory effect on agar BHI. In other bacteria, a partial bacteriostatic effect was observed. Y. enterocolítica was the most sensitive with a CMI 4% and CMB 8 %, followed by E. coli (O157:H7). S. typhi, S. paratyphi B and S. sonnei with CMI 8% and CMB 11% and finally S. flexneri and S. paratyphi A were the most resistant with CMI 11% and CMB 15%. Results indicate that propolis tincture has a bacteriostatic and bactericidal effect in vitro in the strains studied, and that such effect is not due to the ethanol present as solvent.

Calidad microbiológica y bacterias enteropatógenas en vegetales tipo hoja / Microbiological quality and enteropathogenic bacteria in leaf vegetables

Para analizar la calidad microbiológica en vegetales tipo hoja y la incidencia de bacterias enteropatógenas se analizaron 150 muestras (50 lechugas, 50 cilantros y 50 perejiles) recolectadas en dos supermercados de Maracaibo. Se determinó Coliformes Totales (CT) y Escherichia coli (EC) según la norma COVENIN Nº3276:1997; para la determinación de bacterias enteropatógenas (Salmonella, Aeromonas y Vibrio) se utilizaron medios de enriquecimiento y selectivos. La identificación de especies se realizó empleando pruebas bioquímicas. En 81,33% (122/150) de las muestras se obtuvieron contajes de CT entre 10³-10 5 UFC/g. La recuperación de EC fue de 10,00%. La frecuencia de enteropatógenos fue de 28%, siendo Aeromonas el género más aislado con un 95,91%. La mayor recuperación de enteropatógenos se obtuvo en las muestras de cilantro (40,00%), seguida de perejil (34,00%) y lechuga (20,00%); A. caviae fue la especie más recuperada (59,18%) seguida de A. hydrophila (30,62%). Salmonella spp se recuperó en 2 (4,08%) muestras. La presencia de indicadores entéricos (CT y EC) y de bacterias enteropatógenas sugiere que los vegetales tipo hoja presentan una inadecuada calidad sanitaria y pueden ser fuente de gastroenteritis

To analyze the microbiological quality of leaf vegetables and the incidence of enteropathogenic bacteria, 150 samples (50 lettuce, 50 coriander and 50 parsley) collected in two supermarkets in Maracaibo, were studied. Total coliforms (TC) and Escherichia coli (EC) according to COVENIN guideline N° 3276: 1997, were determined; for the identification of enteropathogenic bacteria (Salmonella, Aeromonas, Vibrio), enrichment and selective media were used. Species identification was made using biochemical tests. In 81.33% (122/150) of the samples obtained, TC counts were between 10³-10 5 CFU/g. EC recovery was 10.00%. The frequency of enteropathogens was 28%, with Aeromonas the most isolated genus (95.91%). Greater recovery of enteropathogens was obtained from coriander (40.00%), followed by the parsley (34.00%) and lettuce samples (20.00%); A. caviae was the most recovered specie (59.18%) followed by A. hydrophila (30,62%). Salmonella spp were recovered in 2 samples (4.08%). The presence of enteric indicators (TC and EC) and enteropathogenic bacteria suggests that the sanitary condition of the leafy vegetables is inadequate and can be a source of gastroenteritis

Calidad microbiológica en frutas de conchas comestibles expendidas en mercados populares de los municipios Valencia y San Diego, estado Carabobo, Venezuela / Microbiological quality of fruits that have edible peels sold at popular markets of the Valencia and San Diego Municipalities, Carabobo State, Venezuela

Las frutas constituyen un grupo de nutrientes indispensables para la salud y bienestar del individuo. Se evaluó la calidad microbiológica en frutas de concha comestible (fresas, guayabas y duraznos) expendidas en mercados populares de Valencia y San Diego, estado Carabobo, Venezuela. Se determinó el número de UFC/g de mesófilos aerobios (MA), coliformes totales y fecales (CT, CF) y Salmonella spp. según Normas COVENIN. La mayoría de los recuentos obtenidos de MA fueron elevados en la mayoría de las frutas. Los niveles de contaminación por estos microorganismos se encontraron entre 1,4x10(5) y 6,6x10(10) UFC/g. Los recuentos encontrados para CT generalmente resultaron inferiores a los obtenidos para los MA, y se encontraron en un rango de 2,6x10³ a 7,2 x 10(10) UFC/g. No se detectó la presencia de CF y de Salmonella spp., en las muestras evaluadas. De las frutas analizadas las fresas fueron las que presentaron el mayor grado de contaminación microbiológica tanto por MA como CT. La ausencia de CF y Salmonella spp. sugiere que las condiciones a las cuales fueron sometidas las frutas durante el período de pre y postcosecha, estuvieron aparentemente dentro los límites permisibles de calidad sanitaria.

Fruits constitute a group of indispensable nutrients for the health and wellbeing of individuals. We evaluated the microbiological quality of fruits with edible peels (strawberries, guavas and peaches) sold at popular markets in Valencia and San Diego, Carabobo State, Venezuela. We determined the number of CFU/g of mesophilic aerobics (MA), total and fecal coliforms (TC, FC) and Salmonella spp. according to COVENIN guidelines. Most of the MA counts obtained were high in most fruits. The contamination levels by these microorganisms were found to be between 1.4x10(5) and 6.6x10(10) CFU/g. The counts found for TC were generally lower than those for MA, and occurred in amounts of between 2.6x10³ and 7.2x10(10) CFU/g. The presence of FC and Salmonella spp. was not detected in the samples evaluated. Of the fruits studied, strawberries were the ones which showed the highest microbiological contamination degree both by MA and TC. The absence of TC and Salmonella spp. suggests that the conditions to which the fruits were submitted during the pre and post harvest period apparently were within the permissible limits of sanitary quality.

Isolamento de bactérias enteropatogênicas de coproculturas realizadas durante o período 1977-1983 na Seção de Bacteriologia do Instituto Adolfo Lutz, São Paulo / Isolation of enteropathogenic bacteria from stool cultures performed during the period 1977-1983 at the Bacteriology Section of Instituto Adolfo Lutz, São Paulo

Durante o período compreendido entre 1977 e 1983 foram realizadas 19.284 coproculturas na Seção de Bacteriologia do Instituto Adolfo Lutz. A positividade foi de 31,850/0, onde 15,890/0 pertencia à Salmonella, 12,130/0 à Escherichia coli enteropatogênica, enteroinvasiva e enterotoxigênica, e 3,830/0 à Shigella. Em 11,070/0 dos exames positivos foi isolada mais de uma enterobactéria patogênica em uma mesma amostra. S. typhimurium e S. agona foram os sorotipos mais freqüentes, correspondendo a 89,950/0 do total das salmonelas isoladas. Os sorogrupos de E. coli enteropatogênica de maior incidência foram 0111 e 0119. Entre as E. coli enteroinvasivas, os sorogrupos mais frequentes foram 028ac, 0124 e 0136. Mais de 500/0 das cepas de E. coli enterotoxigênica pertencia ao sorogrupo 0128, e as cepas enterotoxigênicas portadoras dos fatores de colonização CFAjI ou CFAjII correspondiam a aproximadamente 350/0 do total. Assemelhando-se à incidência em outros países, mais de 95% das cepas de Shigella pertencia à Shigella flexneri e à Shigella sonnei. Salmonella, Shigella e E. coli representam, ainda, os principais agentes etiológicos em nosso meio. Durante o período de um ano não foi isolada nenhuma cepa de Yersinia enterocolitica. ° isolamento de Campylobacte.· jejuni, nos dois últimos anos de pesquisa realizada na Seção de Bacteriologia (AU).