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At least 19 recordsLinked to original sources
PubMed1999

Evaluation of a multiplex PCR assay for simultaneous identification of Salmonella sp., Salmonella enteritidis and Salmonella typhimurium from environmental swabs of poultry houses.

A Multiplex PCR-based assay (m-PCR) with three sets of primers was developed for the detection of all serotypes of Salmonella enterica and the identification of Salmonella Enteritidis and Salmonella Typhimurium. This method was evaluated against a bacteriological method for the analysis of environmental swabs of poultry houses. Samples were preenriched in phosphate-buffered peptone water for 24 h and subjected to three different protocols prior to PCR: (i) an immunomagnetic separation using Dynabeads anti-Salmonella (Dynal); (ii) a DNA extraction procedure using the Instagene matrix; (iii) an additional step of culture on an MSRV medium. With protocols 1 and 2, eight positive results were found by PCR and 20 with the bacteriological method. Protocol 3 combining MSRV and PCR gave similar results to those obtained from bacteriological methods and allowed Salmonella detection within 2 days.

Animals↗
PubMedDate not supplied

[Molecular mechanism for pathogenicity of Salmonella sp].

Salmonella is a Gram negative bacillus that behaves like a facultative intracellular pathogen. Its environment is the human and animal gastrointestinal tracts, it is never found like a normal microbiota. It is associated with gastrointestinal problems, septicaemic disease and abortion, due to its cellular invasion capacity and its intraphagocytic survival. Nowadays, it is known that Salmonella contains five pathogenicity islands. Several genes involved in the cellular invasion of nonphagocytic cells such as epithelial cells, apoptosis of macrophages, activation of routes of MAP kinases and transcription factors are located in centisome 63, constituting the pathogenicity island 1 (SPI-1). The SPI-2 and SPI-3 islands control the intracellular survival and replication. The SPI-4 island encodes a putative type I secretion system and its believed that it participates in the intracellular survival. Finally, the SPI-5 island encodes for factors involved in the fluid secretion and inflammatory reaction in the intestinal mucosa. Due to a coordinated and precise regulation of the Salmonella genes, it allows for adaptation to environmental changes that occur during an inflammatory process.

Animals↗
PubMed2025

Detection of the mgtC gene in multidrug-resistant Salmonella sp. based on isolation of chicken eggshell swabs from traditional Surabaya markets.

BACKGROUND: The virulence of Salmonella sp. is increased by the presence of the mgtC gene, which allows the bacteria to survive in environments with low magnesium levels, such as inside macrophages. Salmonella sp. found on eggshells when they show resistance to three or more classes of antibiotics can be classified as multidrug-resistant (MDR) bacteria. AIM: This study aimed to identify the presence of Salmonella sp. MDR and the mgtC gene in chicken eggshell swabs from traditional markets in Surabaya. METHODS: Swab samples were collected from 160 eggs (80 from layer chickens and 80 from free-range chickens) at 10 traditional markets in Surabaya, Indonesia. Isolation and identification were performed using culture media, including Salmonella Shigella Agar, Gram staining, Triple Sugar Iron Agar, Sulfide Indole Motility, Simmons Citrate Agar, Methyl Red and Voges Proskauer, and Urea Agar. Antibiotic sensitivity testing was performed using the disc diffusion method on Mueller-Hinton Agar. Molecular detection of the mgtC gene was performed using polymerase chain reaction. RESULTS: The results showed that 16.87% (27/160) of the samples were detected positive for Salmonella sp. All Salmonella sp. isolates (27) were resistant to Erythromycin (100%). Resistance was also found to Ampicillin (77.77%, 21/27), Tetracycline (29.62%, 8/27), and Ciprofloxacin (18.51%, 5/27). No resistance to chloramphenicol was observed. In addition, eight of the 27 isolates (29.62%) were classified as Salmonella sp. MDR. The Salmonella sp. MDR isolates also carried the mgtC gene at 87.5% (7/8). CONCLUSION: These findings demonstrate the potential global public health threat posed by MDR Salmonella sp. with the mgtC gene, emphasizing the importance of monitoring and controlling antibiotic resistance in humans and animals.

Animals↗
PubMed2006

Unveiling contamination sources and dissemination routes of Salmonella sp. in pigs at a Portuguese slaughterhouse through macrorestriction profiling by pulsed-field gel electrophoresis.

Sixty-nine isolates of Salmonella sp. isolated from the ileum, tonsils, carcass and mandibular and ileocolic lymph nodes of individual pigs slaughtered for consumption in one abattoir were analyzed using serotyping and macrorestriction profiling by Pulsed-Field Gel Electrophoresis (RFLP-PFGE), in order to identify clonal relationships. XbaI macrorestriction was able to distinguish 18 genotypes among the eight identified serotypes: Salmonella Typhimurium (4 genotypes), Salmonella Rissen (3), Salmonella Tennessee (2), Salmonella Enteritidis (2), Salmonella 4,[5],12:i:- (4), Salmonella Give (1), Salmonella Anatum (1), and Salmonella Derby (1). Except for one sample, the serotype and the genotype identified in the samples from the same pork were always the same, allowing to unravel possible dissemination routes of Salmonella sp. through these pork tissues and equate presumptive sources of contamination or infection. Highly significant associations (p < 0.001) were observed for the presence of Salmonella sp. in the ileum and in the ileocolic lymph nodes, as well as between the carcass contamination and the presence of Salmonella sp. in others samples of the correspondent slaughtered pig, such as the ileum, the ileocolic and mandibular lymph nodes and the tonsils. Moreover, 80% of the pigs with ileum and ileocolic lymph nodes positive samples also presented the same salmonella genotype in the correspondent tonsils and, among pigs with positive tonsils, 70% also carried the same genotype in the corresponding mandibular lymph nodes. The occurrence of cross-contamination was also detected, since a genotype identified in other pigs slaughtered in the same day was found in 31% of positive carcasses. The global analysis of the genotypes suggested three different sources of pig infection: the farm of origin, the transportation and the lairage. A particular attention should be paid to the last one, since the majority of the isolates from pig samples were related to infection in the lairage. Since the presence of Salmonella sp. in the ileum of pigs and faeces ingestion promotes tonsils infection and internal dissemination of the agent through the mandibular lymph nodes, as well as drainage to the ileocolic lymph nodes, a potential risk exists at slaughter for Salmonella sp. contamination in the carcasses during pork processing. This risk may be increased by incorrect evisceration techniques and by hygienically inappropriate meat inspection procedures, especially those concerned to the mandibular lymph nodes incisions.

Abattoirs↗
PubMed1981

Homology between the invertible deoxyribonucleic acid sequence that controls flagellar-phase variation in Salmonella sp. and deoxyribonucleic acid sequences in other organisms.

The invertible deoxyribonucleic acid (DNA) segment cloned from Salmonella sp. was radioactively labeled and used as a probe to search for homologous sequences by Southern hybridization. Only one copy of the invertible segment could be found on the Salmonella sp. genome. Partial sequence homology with the invertible region was detected in bacteriophage Mu and P1 DNA by low-stringency hybridization. Under these conditions, no homology was detected with Escherichia coli DNA. A strain of Salmonella sp. defective in phase variation carrying the vH2- allele was also analyzed by DNA-DNA hybridization. The results show that there is sequence divergence between diphasic and vH2- strains within the invertible sequence.

Bacterial Proteins↗
PubMed1991

Use of a Salmonella typhimurium-derived virulence probe in the detection of Salmonella sp. and in the characterization of S. cholerae-suis virulence plasmids.

A genetic probe encoding a virulence gene from Salmonella typhimurium was useful in the detection of Salmonella from feces during an outbreak of salmonellosis at a local dairy. A 3.2-kb BamHI restriction endonuclease fragment of the S. typhimurium virulence plasmid, pStSR100, has been useful as a DNA probe for both detection of Salmonella sp. and characterization of virulence plasmids from numerous field isolates. This virA probe hybridizes to a highly conserved gene carried on the large virulence plasmids of invasive Salmonella isolates. Colony blots prepared from feces directly plated onto MaConkey's agar failed to detect low numbers of Salmonella sp. However, hybridization of the VirA probe to vacuum blots or colony blots prepared from feces in tetrathionate enrichment broth incubated for 16 hours at 37 C was effective for detecting Salmonella sp. and resulted in an 85.9% correlation with culture results. The probe also demonstrated the highly conserved nature (96%) of the virulence gene among S. cholerae-suis isolate plasmids detected using Southern blot analysis.

Animals↗
PubMed2004

AnDiaTec Salmonella sp. PCR-ELISA for analysis of food samples.

A commercially available PCR kit (AnDiaTec Salmonella sp. PCR-ELISA) was developed and evaluated for the detection of Salmonella sp. in food samples. The test is based on PCR amplification and hybridization of the amplified DNA to a microtiter plate followed by the detection of PCR product in the manner of an enzyme-linked immunosorbent assay test. The sensitivity and specificity were evaluated first with Salmonella pure cultures and artificially contaminated food samples, including food types for which an inhibition of the PCR reaction was expected. Both experiments proved a very good sensitivity, specificity, and reliability of the test with a very broad range of food types. In a second evaluation study, more than 1,100 food samples of different types were tested in parallel with the PCR method and with the International Standardization Organization 6579 bacteriological reference method. The results of this evaluation study and the results from other experiments on dilutions of artificially contaminated food samples led to the establishment of a positive-negative cutoff value (optical density at 450 nm of more than 0.9) with respect to the conventional bacteriological method. Using this positive-negative cutoff, 98% agreement to the bacteriological method was obtained.

DNA, Bacterial↗
PubMed2003

Irradiation D-values for Escherichia coli O157:H7 and Salmonella sp. on inoculated broccoli seeds and effects of irradiation on broccoli sprout keeping quality and seed viability.

Like alfalfa sprouts, broccoli sprouts can be a vehicle for bacterial pathogens, which can cause illness when they are consumed. The gamma irradiation process was used to reduce numbers of bacterial pathogens on broccoli sprouts and seeds, and the effect of this process on the seeds was studied. The irradiation destruct values for Salmonella sp. and for strains of Escherichia coli O157:H7 inoculated on broccoli seeds were determined. Results obtained in this study indicate that a dose of 2 kGy reduced total background counts for broccoli sprouts from 10(6) to 10(7) CFU/g to 10(4) to 10(5) CFU/g and increased the shelf life of the sprouts by 10 days. Yield ratio (wt/wt), germination percentage, sprout length, and thickness were measured to determine the effects of various irradiation doses on the broccoli seeds. Results show a decreased germination percentage at a dose level of 4 kGy, whereas the yield ratio (wt/wt), sprout length, and thickness decreased at the 2-kGy dose level. The radiation doses required to inactivate Salmonella sp. and strains of E. coli O157:H7 were higher than previously reported values. D-values, dose required for a 1-log reduction, for the nonvegetable and vegetable Salmonella sp. isolates were 0.74 and 1.10 kGy, respectively. The values for the nonvegetable and vegetable isolated strains of Escherichia coli O157:H7 were 1.43 and 1.11 kGy, respectively. With the irradiation process, a dose of up to 2 kGy can extend the shelf life of broccoli sprouts. A dose of > 2 kGy would have an adverse effect on the broccoli seed and decrease the yield of broccoli sprouts.

Brassica↗
PubMed1995

[Analysis of Salmonella sp. serotypes isolated in Spain en 1988-1992].

BACKGROUND: Salmonella sp. is the main cause of bacterial diarrhoea in Spain. Serotyping, is the most widely applied epidemiological marker. The epidemiological distribution of Salmonella serotypes isolated in Spain is analyzed by statistical methods. METHODS: Salmonella isolates were serotyped according to standard methods and the results were analyzed by the Mantel-Haenszel chi 2 test. RESULTS AND CONCLUSIONS: The number of isolates (20,595) was 17% higher than those analyzed in the previous five year period (1983-1987), mainly due to an increase in the number of isolates from non human origin. The three most commonly isolated serotypes were Enteritidis, Typhimurium and Virchow. Serotype Enteritidis decreased along the analyzed period, probably because of the effectiveness of the socio-sanitary measures taken by the national and regional administrations such as legal issues (use of commercial mayonnaise in restaurants) and sanitary education.

Animals↗
PubMed2005

Isolation of Salmonella sp. in sludge from septage treatment plant.

Waste stabilization ponds (WSP) are an often-used option to treat faecal sludges collected from on-site sanitation systems. Since agricultural use is one of the most attractive options for sludge disposal, specific guidelines on the hygienic sludge quality must be fulfilled, such as for viable helminth eggs and Salmonella sp. Although Salmonella isolation methods are well known for other types of samples, they are not suitable for faecal sludge. The reason can be attributed to the co-existence of a native bacterial sludge flora masking Salmonella development, especially if this bacteria is present at low concentrations. In order to select the best methodology for Salmonella recovery from septage sludge, different culture media were assayed at different incubation periods and temperatures. The proposed methodology for Salmonella recovery from sludge can be summarised as follows: (1) enrichment in Rappaport-Vassiliadis broth at 43 degrees C, 48 hours, and (2) isolation in XLD agar at 40 degrees C, 24 hours. Identification of suspected colonies by biochemical tests: TSI, LIA, urease and serological confirmation with Group O Antigen.

Agar↗
PubMed2005

Sorption kinetics of Escherichia coli and Salmonella sp on two soil layers associated with a groundwater table in Yaounde, Cameroon (Central Africa).

A laboratory study has been carried out on two soil layers (H[X] and H[Y]) located above a groundwater table in Yaounde, Cameroon (Central Africa). The main purpose of this study was to assess the retention potential or sorption kinetics of Escherichia coli and Salmonella sp. on these soil layers. For both soil layers, bacterial sorption on soil particles occurred rapidly during the first 30 minutes of incubation of bacteria and soil particles in aqueous media, and increased gradually with incubation time up to 300 min. In some cases, adsorption rates fluctuated after 30 min of incubation, probably due to bacterial cell sorption to and de-sorption from soil particles. Using Freundlich isotherms, it was noted that adsorption coefficient related to adsorption capacity varied from 19 to 4026 E. coli.mg(-1) of soil, and from 506 to 847 Salmonella sp.mg(-1) of soil. For both bacterial species, the adsorption coefficient of layer H[Y] (located in close proximity of the water table) was greater than that of H[X] (located above layer H[Y]) and seemed to positively correlate with the pH values and N/P ratios, and to negatively correlate with the values of C/N and C/P ratios. The linearity coefficient related to adsorption intensity varied from 0.5841 to 1.0023 for E. coli, and from 0.7068 to 1.5236 for Salmonella sp. The physico-chemical characteristics of soil particles seemed to influence the sorption kinetics of bacteria on soil.

Adsorption↗
PubMed2002

Evaluation of an immunochromatography strip assay for the detection of Salmonella sp. from poultry.

The present study was conducted to evaluate the sensitivity and specificity of an immunochromatography-based diagnostic kit for Salmonella. The analytical sensitivity of the test when using pure colonies of different Salmonella species was in the range of 1 X 10(4) to 1 x 10(5) colony-forming units per milliliter. The strip detected 19 of 22 strains of Salmonella spp. but failed to detect S. worthington, S. choleraesuis var. kunzendorf and S. johannesburg. The strip did not detect 27 different enteric bacteria, including Escherichia coli O157:H7, Campylobacter jejuni, Shigella sonnei, and Vibrio parahaemolyticus. In direct testing of feces (n = 66) from chickens infected with Salmonella typhimurium, the strip had a sensitivity of 12.3% and a specificity of 100%. Evaluation of the strip assay (n = 510) after sample pre-enrichment in 2% buffered peptone water (BPW) yielded a sensitivity of 93.8% and specificity of 89% when compared to isolation and identification with xylose-lysine-tergitol 4 (XLT4) selective plating media. Subsequent enrichment in Hajna tetrathionate (TT) broth yielded a higher sensitivity (94.7%) and specificity (96.8%). The agreement (kappa) between the strip test and isolation was 0.004 in direct fecal testing, 0.82 in BPW, and 0.89 in TT broth. The assay could detect Salmonella sp. as early as 18-48 hours during pre-enrichment and enrichment compared to isolation on XLT4, which required an overnight incubation step for the presumptive isolation and identification of Salmonella.

Animals↗
PubMed1987

Raw beef, pork and chicken in Japan contaminated with Salmonella sp., Campylobacter sp., Yersinia enterocolitica, and Clostridium perfringens--a comparative study.

One hundred and twenty samples each of raw ground beef, pork and chicken from ten local grocery stores in Shimane Prefecture, Japan, were examined for the presence of Salmonella sp. (Sal), Campylobacter jejuni (Cj), Campylobacter coli (Cc), Yersinia enterocolitica (Ye), and Clostridium perfringens (Cp) from April 1984 to March 1985. A total of 205 isolates of Sal (112 strains), Cj (64 strains), Cc (one strain), Ye (7 strains) and Cp (21 strains) were recovered from 17 beef (14.2%), 31 pork (25.8%) and 94 chicken (78.3%) of 120 samples each. Sal biogroup 1 was found in 8.3% of beef, 13.3% of pork and 35.0% of chicken, Sal biogroup 2 in 0.8% of beef, 4.2% of pork and 14.2% of chicken, Cj in 1.7% of beef and pork and 50.0% of chicken, Cc in 0.8% of pork, Ye serotype 03 was found in 5.0% of pork, and Cp in 1.7% of beef and pork and 10.8% of chicken. These enteropathogens were recovered concomitantly from two pork and 31 chicken samples, especially Sal and Cj. Sal was counted at less than or equal to 10(2)/100 g of beef and pork and at less than or equal to 10(3)/100 g of chicken, Cj was counted at less than or equal to 10(1)/g of beef and pork and at less than or equal to 10(2)/g of chicken, Ye serotype 03 was counted at less than or equal to 10(3)/g of pork, Cp was counted at less than or equal to 10(2)/g of pork and at less than or equal to 10(2)g of chicken, and Cc from pork and Cp from beef were recovered by using enrichment culture. This investigation showed that a second-contamination of Sal and Cj from chicken to beef and pork frequently occurred during the warm months of the year. It was suggested that chicken may become a source of infection with plural organisms of enteric pathogens, especially Sal and Cj, at the same time all the year round, and that pork may be an important source of infection with Ye during the cold months.

Animals↗
PubMed1995

Influence of freshwater sediment on the survival of Escherichia coli and Salmonella sp. as measured by three methods of enumeration.

Growth and survival of enteric bacteria in freshwater sediments should be of concern to public health officials because of potential contributions of bacteria to the water column. Bacteria densities were measured in sediment and water using direct counts (DC), direct viable counts (DVC) and standard plate counts (PC). Both Salmonella sp. and Escherichia coli survived in microcosms containing autoclaved water and sediment for at least 28 d, as measured by all three methods of enumeration. Moreover, when bacteria were enumerated from sediment-containing microcosms, the DC, DVC and PC values were equivalent. Plate counts showed that both organisms were present at high densities on day 56. In addition, parallel platings on MacConkey agar of E. coli from microcosms containing sediment gave results identical to PC values, indicating that E. coli was not stressed in these microcosms. In microcosms containing water only, E. coli densities declined gradually over 2 weeks by all three measures of enumeration. By day 14, only 58% of total DC was viable as measured by DVC. Due to the protective nature of sediments, the use of standard media may be adequate to enumerate E. coli from some freshwater sediments.

Colony Count, Microbial↗
PubMed1994

[Evaluation of three new culture media: brilliant-glycerol-lactose novobiocin-green agar, modified iron lysin agar and Rambach agar for the isolation of enteropathogenic E. coli, Salmonella sp. in acute gastroenteritis].

BACKGROUND: Acute gastroenteritis (AGE) is one of the most common diseases in children, particularly in those under the age of 5 years in whom a severe picture of hydroelectrolyte imbalance may be triggered accompanied, in most cases, by leukocyte response. The aim of this study was to evaluate three new culture media for the isolation of enteropathogens in infantile diarrhea. MATERIAL AND METHODS: From April to September, 1993, 170 samples of diarrhea stools from children up to 7 years of age attending pediatric hospitals in Bogota were studied. Three new culture media were used in the isolation of the enteropathogenic bacteria: BGLN, MILA agar, Rambach agar and a conventional agar medium S.S. Biochemical tests were performed to identify the isolated bacteria. RESULTS: A total of 98.5% of enteropathogenic E. coli was isolated in Rambach agar, which also presented excellent recovery rates of Salmonella sp. (100%) versus S.S> (64.3%) and BGLN (77.2%), respectively. The best selectivity for Shigella sp. was observed with BGLN with a 100% recovery rate. Out of the 170 samples 105 showed a leukocyte count of 70-75% and positive isolation for enteropathogenic bacteria. Six samples with the same leukocyte count did not present enteropathogenic bacteria, with the 59 remaining samples with a 20-25% PMN count being negative for enteropathogenic bacteria. CONCLUSIONS: The results suggest that the new culture media used in this study may have better recovery rates for enteropathogenic bacteria in acute gastroenteritis. Likewise, a correlation was observed between leukocyte count and isolation enteropathogenic bacteria.

Acute Disease↗
PubMed1995

Chemiluminescent and colorimetric enzymatic assays for the detection of PCR-amplified Salmonella sp. products in microplates.

To improve Salmonella detection, we developed nonradioactive hybridization assays of amplified products from pure Salmonella cultures. Biotin-labeled PCR products were trapped by internal probes covalently bound to CovaLink-NH MicroWells and detected by colorimetric or chemiluminescent enzymatic reactions. The sensitivities of colorimetric assays using peroxidase and alkaline phosphatase were similar to those obtained with an ethidium bromide-stained agarose gel; both procedures allow the detection of 50 Salmonella cells. Chemiluminescence was 10-fold more sensitive than colorimetry.

Alkaline Phosphatase↗