scholarly journals Preliminary assessment of small scale bacterial depuration of Crassostrea gigas and Anadara spp., Gulf of Nicoya, Costa Rica

2013 ◽  
Vol 5 ◽  
pp. 107
Author(s):  
Luis A. Vega Corrales ◽  
Carolina Marín Vindas ◽  
Oscar Pacheco Prieto ◽  
Gerardo Zúñiga Calero
Keyword(s):  
Escherichia Coli ◽  
Costa Rica ◽  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Small Scale ◽  
Bivalve Molluscs ◽  
Salmonella Spp ◽  
E Coli ◽  
Gulf Of Nicoya

Bivalve molluscs are sold without any sanitary control in Costa Rica, which represents a public health risk dueto the possible accumulation of pathogenic bacteria. Small scale bacterial depuration treatments were preliminarilyevaluated on Crassostrea gigas and Anadara spp. from the Gulf of Nicoya, Costa Rica, through the useof a recirculating system with UV irradiation. The levels of Escherichia coli in the water were determined usingthe MPN method. The MPN of E. coli and the presence of Salmonella spp., Vibrio parahaemolyticus and V. cholerae were determined in molluscs. Results confirm the effectiveness of the E. coli depuration system designin C. gigas and Anadara spp. The MPN of E. coli in the molluscs was reduced between 79% and 100% after 24h. None of the other types of bacteria were found in the samples analyzed. This is the first C. gigas depurationstudy in Costa Rica and the first report concerning UV depuration for bacterial indicators of fecal contaminationin Anadara spp. This research serves as a basis for the implementation and improvement of mollusc purification conditions in the country. It is recommended to monitor extraction and harvesting areas, as well as to implement the depuration of bivalve molluscs so that traditional producers can offer an innocuous product with added value.Los moluscos bivalvos son comercializados sin ningún control sanitario en Costa Rica; por tanto, representan un riesgo para la salud pública, debido a que pueden acumular bacterias patógenas. Se evaluaron preliminarmente tratamientos para la depuración bacteriana a pequeña escala de Crassostrea gigas y Anadara spp. en el Golfo de Nicoya, Costa Rica, utilizando un sistema recirculado e irradiado con luz UV. Los niveles de Escherichia coli en el agua se determinaron mediante el método del NMP. A los moluscos se les determinó el NMP de E. coli y la presencia de Salmonella spp., Vibrio parahaemolyticus y V. cholerae. Los resultados confirman la efectividad del diseño del sistema para la depuración de E. coli en C. gigas y Anadara spp. A las 24 h, el NMP de E. coli en los moluscos se redujo entre el 79% y el 100%. No se comprobó la presencia de las demás bacterias en las muestras analizadas. Este es el primer estudio sobre depuración de C. gigas en Costa Rica y el primer reporte de depuración con UV de indicadores bacterianos de contaminación fecal en Anadara spp. Este trabajo sirve de base para implementar y mejorar las condiciones de la depuración de moluscos en el país. Se recomienda monitorear las áreas de extracción y cultivo e implementar la depuración de los moluscos bivalvos para que los productores artesanales puedan ofrecer un producto inocuo y con valor agregado.

scholarly journals Preliminary assessment of small scale bacterial depuration of Crassostrea gigas and Anadara spp., Gulf of Nicoya, Costa Rica

2013 ◽  
Vol 5 ◽  
pp. 107
Author(s):  
Luis A. Vega Corrales ◽  
Carolina Marín Vindas ◽  
Oscar Pacheco Prieto ◽  
Gerardo Zúñiga Calero
Keyword(s):  
Escherichia Coli ◽  
Costa Rica ◽  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Small Scale ◽  
Bivalve Molluscs ◽  
Salmonella Spp ◽  
E Coli ◽  
Gulf Of Nicoya

Bivalve molluscs are sold without any sanitary control in Costa Rica, which represents a public health risk dueto the possible accumulation of pathogenic bacteria. Small scale bacterial depuration treatments were preliminarilyevaluated on Crassostrea gigas and Anadara spp. from the Gulf of Nicoya, Costa Rica, through the useof a recirculating system with UV irradiation. The levels of Escherichia coli in the water were determined usingthe MPN method. The MPN of E. coli and the presence of Salmonella spp., Vibrio parahaemolyticus and V. cholerae were determined in molluscs. Results confirm the effectiveness of the E. coli depuration system designin C. gigas and Anadara spp. The MPN of E. coli in the molluscs was reduced between 79% and 100% after 24h. None of the other types of bacteria were found in the samples analyzed. This is the first C. gigas depurationstudy in Costa Rica and the first report concerning UV depuration for bacterial indicators of fecal contaminationin Anadara spp. This research serves as a basis for the implementation and improvement of mollusc purification conditions in the country. It is recommended to monitor extraction and harvesting areas, as well as to implement the depuration of bivalve molluscs so that traditional producers can offer an innocuous product with added value.Los moluscos bivalvos son comercializados sin ningún control sanitario en Costa Rica; por tanto, representan un riesgo para la salud pública, debido a que pueden acumular bacterias patógenas. Se evaluaron preliminarmente tratamientos para la depuración bacteriana a pequeña escala de Crassostrea gigas y Anadara spp. en el Golfo de Nicoya, Costa Rica, utilizando un sistema recirculado e irradiado con luz UV. Los niveles de Escherichia coli en el agua se determinaron mediante el método del NMP. A los moluscos se les determinó el NMP de E. coli y la presencia de Salmonella spp., Vibrio parahaemolyticus y V. cholerae. Los resultados confirman la efectividad del diseño del sistema para la depuración de E. coli en C. gigas y Anadara spp. A las 24 h, el NMP de E. coli en los moluscos se redujo entre el 79% y el 100%. No se comprobó la presencia de las demás bacterias en las muestras analizadas. Este es el primer estudio sobre depuración de C. gigas en Costa Rica y el primer reporte de depuración con UV de indicadores bacterianos de contaminación fecal en Anadara spp. Este trabajo sirve de base para implementar y mejorar las condiciones de la depuración de moluscos en el país. Se recomienda monitorear las áreas de extracción y cultivo e implementar la depuración de los moluscos bivalvos para que los productores artesanales puedan ofrecer un producto inocuo y con valor agregado.

scholarly journals Detection of Salmonella spp. and diarrheagenic Escherichia coli in fresh pork sausages

2018 ◽  
Vol 39 (4) ◽  
pp. 1533
Author(s):  
Paola Bianca Barbosa Cavalin ◽  
Juan Josue Puño Sarmiento ◽  
Renata Katsuko Takayama Kobayashi ◽  
Gerson Nakazato ◽  
Armando Navarro Ocaña ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Meat Products ◽  
Economic Losses ◽  
Processing Plant ◽  
Pathogenic Microorganisms ◽  
Salmonella Spp ◽  
Pork Sausage ◽  
E Coli ◽  
Inspection Service

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.

scholarly journals Assessment of a multiplex detection method for Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes in cow milk

2019 ◽  
Vol 24 (1) ◽  
pp. 277-294
Author(s):  
Rocio Esperanza Patiño-Burbano ◽  
Ana Karina Carrascal ◽  
Jorge Luis Parra-Arango ◽  
José Luis Rodríguez-Bautista
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Detection Rate ◽  
Pathogenic Bacteria ◽  
Simultaneous Detection ◽  
Cow Milk ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
E Coli ◽  
Microbiological Methods

Raw cow milk is considered one of the most important vehicles for pathogenic bacteria like Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. These three bacteria are responsible for foodborne diseases. Routine microbiological methods to detect these microorganisms in cow milk can be complicated and time consuming. The aim of this work was to evaluate a method to simultaneously detect Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes in experimentally contaminated cow milk. The assessed method combined a standard microbiological culture step, using a pre-enrichment medium that favors the growth of the three focal microorganisms: SEL broth, followed by a single PCR assay. A total of 43 interference bacterial strains were used to evaluate the method’s specificity. The detection rate for the microbiological method with standard culture media was 10 UFC/mL, and that of the PCR detection, following pre-enrichment in SEL broth, was 10 UFC/mL for S. enterica and L. monocytogenes and between 1 and 5 UFC/mL for E. coli O157:H7. The PCR method showed specificity for the reference strains. Simultaneous detection by multiple PCR using SEL broth was successful for the detection of S. enterica, E. coli O157:H7, and L. monocytogenes in samples of experimentally contaminated cow milk, featuring both a high detection rate and a high specificity. This approach promises to be a feasible routine procedure when testing milk samples in industry and public health control setups.

scholarly journals Escherichia coli as Commensal and Pathogenic Bacteria among Food-Producing Animals: Health Implications of Extended Spectrum β-Lactamase (ESBL) Production

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2239
Author(s):  
Sónia Ramos ◽  
Vanessa Silva ◽  
Maria de Lurdes Enes Dapkevicius ◽  
Manuela Caniça ◽  
María Teresa Tejedor-Junco ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Severe Infection ◽  
Farm Animals ◽  
Neonatal Meningitis ◽  
Salmonella Spp ◽  
E Coli

Escherichia coli are facultative, anaerobic Gram-negative rods with many facets. Within resistant bacterial populations, they play an important ecological role and can be used as a bioindicator of antimicrobial resistance. All animal species used for food production, as well as humans, carry E. coli in their intestinal tracts; plus, the genetic flexibility and adaptability of this bacteria to constantly changing environments allows it to acquire a great number of antimicrobial resistance mechanisms. Thus, the prevalence of antimicrobial resistance in these commensal bacteria (or others, such as enterococci) can be a good indicator for the selective pressure caused by the use of antimicrobial agents, providing an early warning of the emergence of antimicrobial resistance in pathogens. As many as 90% of E. coli strains are commensals inhabiting the intestinal tracts of humans and warm-blooded animals. As a commensal, it lives in a mutually beneficial association with its hosts and rarely causes diseases. However, E. coli also remains as one of the most frequent causes of several common bacterial infections in humans and animals. In humans, it is the prominent cause of enteritis, community- and hospital-acquired urinary tract infection (UTI), septicemia, postsurgical peritonitis, and other clinical infections, such as neonatal meningitis, while, in farm animals, it is more prominently associated with diarrhea. On a global scale, E. coli can be considered the most important human pathogen, causing severe infection along with other major bacterial foodborne agents, such as Salmonella spp. and Campylobacter. Thus, the importance of resistance in E. coli, typically considered a benign commensal, should not be underestimated.

Rapid and Simultaneous Detection of Vibrio parahaemolyticus, Salmonella spp. and Escherichia coli in Fish by Multiplex PCR

2020 ◽  
Vol 15 (2) ◽  
pp. 53
Author(s):  
Radestya Triwibowo ◽  
Novalia Rachmawati ◽  
Dwiyitno Dwiyitno
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Internal Control ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Target Genes ◽  
Simultaneous Detection ◽  
Salmonella Spp ◽  
Fish Products ◽  
Confirmatory Assay

Pathogenic bacteria are commonly found as natural contaminants in seafood and fish products. Globally, several countries have been imposing strict regulations on the maximum levels of pathogens and consequently require microbial testing of pathogens before the products can be marketed. A culture-based method with biochemical assay has been widely used to detect pathogenic bacteria in food, despite its long and extensive process. Meanwhile, the alternative molecular-based method to overcome this problem, cannot differentiate between viable and nonviable cells, which may lead to underestimation. This study aimed to develop a multiplex PCR (mPCR) method as a confirmatory assay for the culture-based method to detect pathogens in fish products simultaneously. This method applied a pre-enrichment step to ensure the growth of low-level pathogens and the injured cells in the sample. The target genes were ToxR, InvA, and UidA for Vibrio parahaemolyticus, Salmonella spp. and Escherichia coli, respectively. This assay also amplified the 16S rDNA gene of bacteria as an internal control for the PCR reaction. By implementing liquid-based DNA extraction during analysis, the developed-mPCR was comparable to detect the targeted bacteria in artificially-contaminated samples. The method was more sensitive in naturally-contaminated samples, where the number of E. coli, Salmonella spp. and V. parahaemolyticus detected were 28, 7, and 22, respectively. While the conventional method only detected 26, 5, and 19 of the respective pathogens. With a relatively shorter time and lower operation cost, the mPCR method is potential as an alternative for the culture-based method.

scholarly journals High-density transposon libraries utilising outward-oriented promoters identify mechanisms of action and resistance to antimicrobials

2020 ◽  
Vol 367 (22) ◽  
Author(s):  
Chris Coward ◽  
Gopujara Dharmalingham ◽  
Omar Abdulle ◽  
Tim Avis ◽  
Stephan Beisken ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Selective Advantage ◽  
Mechanisms Of Action ◽  
Over Expression ◽  
E Coli ◽  
Synthase Inhibitor ◽  
Established Technique ◽  
Bacterial Transposon

ABSTRACT The use of bacterial transposon mutant libraries in phenotypic screens is a well-established technique for determining which genes are essential or advantageous for growth in conditions of interest. Standard, inactivating, transposon libraries cannot give direct information about genes whose over-expression gives a selective advantage. We report the development of a system wherein outward-oriented promoters are included in mini-transposons, generation of transposon mutant libraries in Escherichia coli and Pseudomonas aeruginosa and their use to probe genes important for growth under selection with the antimicrobial fosfomycin, and a recently-developed leucyl-tRNA synthase inhibitor. In addition to the identification of known mechanisms of action and resistance, we identify the carbon–phosphorous lyase complex as a potential resistance liability for fosfomycin in E. coli and P. aeruginosa. The use of this technology can facilitate the development of novel mechanism-of-action antimicrobials that are urgently required to combat the increasing threat worldwide from antimicrobial-resistant pathogenic bacteria.

PCR for the Specific Detection of an Escherichia coli O157:H7 Laboratory Control Strain

2015 ◽  
Vol 78 (9) ◽  
pp. 1738-1744 ◽  
Author(s):  
MICHAEL KNOWLES ◽  
DOMINIC LAMBERT ◽  
GEORGE HUSZCZYNSKI ◽  
MARTINE GAUTHIER ◽  
BURTON W. BLAIS
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Control Measure ◽  
Positive Control ◽  
Food Microbiology ◽  
Escherichia Coli O157 ◽  
Control Strain ◽  
E Coli ◽  
Signature Sequences ◽  
Materials Used

Control strains of bacterial pathogens such as Escherichia coli O157:H7 are commonly processed in parallel with test samples in food microbiology laboratories as a quality control measure to assure the satisfactory performance of materials used in the analytical procedure. Before positive findings can be reported for risk management purposes, analysts must have a means of verifying that pathogenic bacteria (e.g., E. coli O157:H7) recovered from test samples are not due to inadvertent contamination with the control strain routinely handled in the laboratory environment. Here, we report on the application of an in-house bioinformatic pipeline for the identification of unique genomic signature sequences in the development of specific oligonucleotide primers enabling the identification of a common positive control strain, E. coli O157:H7 (ATCC 35150), using a simple PCR procedure.

Mannose-Binding Activity of Escherichia coli: a Determinant of Attachment and Ingestion of the Bacteria by Macrophages

1980 ◽  
Vol 29 (2) ◽  
pp. 417-424
Author(s):  
Zvi Bar-Shavit ◽  
Rachel Goldman ◽  
Itzhak Ofek ◽  
Nathan Sharon ◽  
David Mirelman
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Pathogenic Bacteria ◽  
Binding Activity ◽  
Exponential Phase ◽  
Restrictive Temperature ◽  
Filamentous Bacteria ◽  
Phagocytic Cells ◽  
E Coli ◽  
Mannose Binding

Recently, it was suggested that a mannose-specific lectin on the bacterial cell surface is responsible for the recognition by phagocytic cells of certain nonopsonized Escherichia coli strains. In this study we assessed the interaction of two strains of E. coli at different phases of growth with a monolayer of mouse peritoneal macrophages and developed a direct method with [ 14 C]mannan to quantitate the bacterial mannose-binding activity. Normal-sized bacteria were obtained from logarithmic and stationary phases of growth. Nonseptated filamentous cells were formed by growing the organisms in the presence of cephalexin or at a restrictive temperature. Attachment to macrophages of all bacterial forms was inhibited by methyl α- d -mannoside and mannan but not by other sugars tested. The attachment of stationary phase and filamentous bacteria to macrophages, as well as their mannose-binding activity, was similar, whereas in the exponential-phase bacteria they were markedly reduced. The results show a linear relation between the two parameters ( R = 0.98, P < 0.001). The internalization of the filamentous cells attached to macrophages during 45 min of incubation was much less efficient (20%) compared to that of exponential-phase, stationary-phase, or antibody-coated filamentous bacteria (90%). The results indicate that the mannose-binding activity of E. coli determines the recognition of the organisms by phagocytes. They further suggest that administration of β-lactam antibiotics may impair elimination of certain pathogenic bacteria by inducing the formation of filaments which are inefficiently internalized by the host's phagocytic cells.

scholarly journals Detection and Quantification of Superoxide Formed within the Periplasm of Escherichia coli

2006 ◽  
Vol 188 (17) ◽  
pp. 6326-6334 ◽  
Author(s):  
Sergei Korshunov ◽  
James A. Imlay
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Phagocytic Cells ◽  
Free Living ◽  
E Coli ◽  
Superoxide Formation ◽  
Genes Encoding ◽  
Copper Zinc ◽  
Primary Substrate

ABSTRACT Many gram-negative bacteria harbor a copper/zinc-containing superoxide dismutase (CuZnSOD) in their periplasms. In pathogenic bacteria, one role of this enzyme may be to protect periplasmic biomolecules from superoxide that is released by host phagocytic cells. However, the enzyme is also present in many nonpathogens and/or free-living bacteria, including Escherichia coli. In this study we were able to detect superoxide being released into the medium from growing cultures of E. coli. Exponential-phase cells do not normally synthesize CuZnSOD, which is specifically induced in stationary phase. However, the engineered expression of CuZnSOD in growing cells eliminated superoxide release, confirming that this superoxide was formed within the periplasm. The rate of periplasmic superoxide production was surprisingly high and approximated the estimated rate of cytoplasmic superoxide formation when both were normalized to the volume of the compartment. The rate increased in proportion to oxygen concentration, suggesting that the superoxide is generated by the adventitious oxidation of an electron carrier. Mutations that eliminated menaquinone synthesis eradicated the superoxide formation, while mutations in genes encoding respiratory complexes affected it only insofar as they are likely to affect the redox state of menaquinone. We infer that the adventitious autoxidation of dihydromenaquinone in the cytoplasmic membrane releases a steady flux of superoxide into the periplasm of E. coli. This endogenous superoxide may create oxidative stress in that compartment and be a primary substrate of CuZnSOD.

scholarly journals The Survey of Microbial Quality of the Dry Sample, Extract and Brewing of some Medicinal Plants

2014 ◽  
Vol 6 (4) ◽  
pp. 478-482
Author(s):  
Razieh VALIASILL ◽  
Majid AZIZI ◽  
Maasome BAHREINI ◽  
Hossein AROUIE
Keyword(s):  
Medicinal Plants ◽  
Pathogenic Bacteria ◽  
Agar Medium ◽  
Total Count ◽  
Plate Count ◽  
Microbial Quality ◽  
Salmonella Spp ◽  
E Coli ◽  
Wide Range

Medicinal plants may be exposed to a wide range of microbial contamination during pre- and post- harvest stages and they can present high microbial counts. In this study, the microbial quality of 44 samples of dry herbs namely: mint (Menthaspp.), lemon balm (Melissa officinalis), summer savory (Satureja hortensis), zataria (Zataria multiflora), Indian valerian (Valeriana wallichii), their brewing and extracts were analyzed. Total count using plate count agar medium (PCA), coliform count by Violet Red Bile Agar (VRBL), Enterobacteriacea by Violet Red Bile Glucose (VRBG) were evaluated. Medium Baird-Parker agar (BP) medium and Tryptone Bile X-Gluc (TBX) medium were used for the isolation and enumeration of Staphylococcus aurous and E. coli spp. respectively. Furthermore, Xylose Lysine Deoxycholate agar medium (XLD) and Bismuth Sulfite Agar medium(BSA) were used for detection of Salmonella spp. Fungal and mold contamination was assessed using yeast extract glucose chloramphenicol agar. The results showed that the contamination of the samples with total count (100%) and Enterobacteriaceae (85%), total coliform (83%), mold and yeast (98%) and E. coli ssp. (2.27) were detected, including in the study samples the absence of pathogenic bacteria like Staphylococcus aurous, Salmonella spp. Moreover, the extract had a lower microbial load in comparison to dry herb samples. Also, the lowest and the highest of contamination rates were observed for Indian valerian and zataria, respectively. According to the results, there is a need to control the environmental conditions and improve hygiene in the production process; even more, it is recommended to choose a suitable decontamination method for disinfection during packing medicinal plants and during post-packing manipulation and transport.

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