Salmonella

Salmonella minnesota R595 bacteria were stripped of their natural antigenic determinants to yield acid-treated, naked bacteria. The proteins, human apolipoprotein A1 and carcino-embryonic antigen, were adsorbed to naked bacteria and these complexes were used to immunise rabbits. Although the antibody titres obtained were comparable to those achieved using Freund's adjuvant emulsions, much less antigen was needed for immunisation. This technique could be of great value where the amount of protein available for immunisation is very small.

A Salmonella permanece um importante problema na avicultura e, considerando os patógenos transmitidos por alimentos, aparece como um dos agentes principais em surtos de toxinfecções alimentares. Para auxiliar na avaliação de riscos em adquirir infecção alimentar via carne de frangos que sofreram cocção inadequada, ou através de contaminação cruzada a partir desses animais, torna-se importante determinar a extensão de contaminação por patógenos em carne crua. No presente trabalho, foram analisadas 180 carcaças de frangos resfriadas, adquiridas em varejos, para pesquisa de Salmonella com determinação do número de células da bactéria. Foi utilizado o método do número mais provável (NMP) nos ágares para isolamento verde brilhante com novobiocina (BGN) e xilose-lisina tergitol 4 (XLT4). Os resultados mostraram 12,2% de ocorrência de Salmonella nas carcaças de frangos resfriadas e a média de NMP de Salmonella por mL, na leitura pelo ágar XLT4 foi de 2,7 células e no ágar BGN foi de 1,3 cé...

The prevalence and characteristics of Escherichia coli and Salmonella spp. as well as counts of E. coli in raw oysters, condiments/spices, and raw oyster cocktails sampled from 72 vendors across Western Trinidad were determined. The microbial quality of the water used in the preparation of raw oysters was also investigated. Of 200 samples each of raw oysters, condiments/spices and oyster cocktails tested, 154 (77.0%), 89 (44.5%) and 154 (77.0%) respectively yielded E. coli. The differences were statistically significant (P = < 0.001; chi square = 62.91). The mean E. coli count per g in the ready-to-eat oyster cocktail ranged from 1.5 x 10(3) +/- 2.7 x 10(3) in Couva to 8.7x10(6) +/- 4.9x10(7) in San Fernando. One hundred and forty-six (73.0%) oyster cocktails contaminated with E. coli had counts that exceeded the recommended standard of 16 per g. Of a total of 590 E. coli isolates from various sources tested, 24 (4.1%), 20 (3.4%) and 69 (11.7%) were mucoid, haemolytic and non-sor...

The microbiological standard for detection of Salmonella relies on several cultural steps and requires more than 5 days for final confirmation, and as consequence there is a need for an alternative rapid methodology for its detection. The aim of this study was to compare different detection strategies based on real-time PCR for a rapid and sensitive detection in an ample range of food products: raw pork and poultry meat, ready to eat lettuce salad and raw sheep milk cured cheese. Three main parameters were evaluated to reduce the time and cost for final results: the initial sample size (25 and 50 g), the incubation times (6, 10 and 18 h) and the bacterial DNA extraction (simple boiling of the culture after washing the bacterial pellet, the use of the Chelex resin, and a commercial silica column). The results obtained demonstrate that a combination of an incubation in buffered peptone water for 18 h of a 25 g-sample coupled to a DNA extraction by boiling and a real-time PCR assay detected down to 2-4 Salmonella spp. CFU per sample in less than 21 h in different types of food products. This RTi-PCR-based method is fully compatible with the ISO standard, providing results more rapidly and cost-effectively. The results were confirmed in a large number of naturally contaminated food samples with at least the same analytical performance as the reference method.

Tuberculosis (TB) is one of the leading infectious causes of death due to single infectious agent after HIV/AIDS. Rifampicin (RIF), Isoniazid (INH), Ethambutol (EMB), Pyrazinamide (PZA) and/or their combinations are extensively prescribed to treat TB. Despite several therapeutic implications, these drugs also produce several toxic effects at cellular level. MTT assay and Ames test were adopted in this study for the determination of cytotoxic and mutagenic potential of these anti-TB drugs. Among all tested drugs, cytotoxic potential of RIF was strongest with highly significant decline (p < 0.001) in cell numbers at the concentration of 250 g/ml with LC 50 at 325 g/ml, while significant decline (p < 0.01) in cell count was observed in INH treated group at the concentration 500 g/ml with LC 50 at 1000 g/ml. Moreover, combination RIPE demonstrated significant reduction (p < 0.01) in cell number at the concentration of 25-500-500-500 g/ml with LC 50 at 60-1200-1200-1200 g/ml. It is apparent from the data that almost all drugs represented identical mutagenic pattern i.e., more significant results were achieved in TA100 with metabolic activation (+S9). RIF proved to be highly mutagenic of all tested drugs with significant mutagenicity (p < 0.01) at 0.0525 g/plate against TA98 strain with S9. The combination RIPE exhibited highly significant mutagenic activity (p < 0.01) at concentration 0.125-3-3-3 g/plate without S9, while addition of S9 resulted in similar activity at lower doses, i.e., 0.0525-1-1-1 g/plate. It was concluded from the data that all anti-TB drugs possess significant cytotoxic and mutagenic potential, especially in combination, making TB patient more vulnerable to cytotoxic and mutagenic effects of anti-TB drugs, which could produce further health complications in TB patients.

Aims:  To determine the counts and/or prevalence in fresh bovine faeces of Escherichia coli, enterococci, Campylobacter, Salmonella, shiga toxin-producing E. coli (STEC), Giardia and Cryptosporidium, as inputs to numerical models designed to estimate microbial loadings on pasture grazed by cattle in New Zealand.Methods and Results:  In each season over one year, samples of freshly deposited bovine faeces were collected from four New Zealand dairy farms (n = 155), and enumerated for E. coli, enterococci, Campylobacter, Giardia and Cryptosporidium. They were also tested for the presence of Salmonella and STEC. The overall median bacterial counts (g−1 wet weight) were E. coli– 5·9 × 106; enterococci – 1·3 × 104; Campylobacter– 3·9 × 105. All counts were highly variable within and between samplings, and few seasonal or regional patterns emerged. However, mean Campylobacter counts were consistently higher in spring. No Salmonella spp. was detected, and only two samples were positive for STEC. Cryptosporidium and Giardia were isolated from 5·2% and 4·5% of the samples, respectively, yielding low numbers of (oo)cysts (1–25 g−1 and 1–17 g−1, respectively).Conclusions:  Fresh bovine faeces are a significant source of E. coli, enterococci and Campylobacter on New Zealand pastures, although numbers are likely to vary markedly between faecal samples.Significance and Impact of the Study:  The study provides the first significant set of indicator and pathogen counts for one of the largest sources of faecal contamination of natural waters in New Zealand, and will be used to model these inputs.

Six strains of Salmonella (Anatum F4317, Dublin 15480, Enteritidis 13076, Enteritidis WY15159, Stanley H0588, and Typhimurium 14028) were individually inoculated into orange juice concentrate (OJC) and frozen to -20 degrees C. The frozen samples were treated with 0 (nonirradiated), 0.5, 1.0, or 2.0 kGy of gamma radiation and held frozen for 1 h, and the surviving bacterial population was assessed. The strains showed significant variability in their response to freezing and to freezing in combination with irradiation. The response was dose dependent. Relative to the nonfrozen, nonirradiated control, the reduction following the highest dose (2.0 kGy) ranged from 1.29 log CFU/ml (Salmonella Typhimurium) to 2.17 log CFU/ml (Salmonella Stanley). Samples of OJC inoculated with Salmonella Enteritidis WY15159 and irradiated were stored at -20 degrees C for 1, 2, 7, or 14 days, and the surviving population was determined. Relative to the nonfrozen, nonirradiated control, after 14 days, the p...

Aromatic amines represent one of the most important classes of industrial and environmental chemicals: many of them have been reported to be powerful carcinogens and mutagens, and/or hemotoxicants. Their toxicity has been studied also with quantitative structure-activity relationship (QSAR) methods: these studies are potentially suitable for investigating mechanisms of action and for estimating the toxicity of compounds lacking experimental determinations. In this paper, we first summarized the QSAR models for the rodent carcinogenicity of the aromatic amines. The gradation of potency of the carcinogenic amines depended firstly on their hydrophobicity, and secondly on electronic (reactivity, propensity to be metabolically transformed) and steric properties. On the contrary, the difference between carcinogenic and non-carcinogenic aromatic amines depended mainly on electronic and steric properties. These QSARs can be used directly for estimating the carcinogenicity of aromatic amines. A two-step prediction is possible: (1) estimation of yes/no activity; (2) if the answer from step 1 is yes, then prediction of the degree of potency. The QSARs for rodent carcinogenicity were put in a wider context by comparing them with those for: (a) Salmonella mutagenicity; (b) general toxicity; (c) enzymatic reactions; (d) physical-chemical reactions. This comparative QSAR exercise generated a coherent global picture of the action mechanisms of the aromatic amines. The QSARs for carcinogenicity were similar to those for Salmonella mutagenicity, thus pointing to a similar mechanism of action. On the contrary, the general toxicity QSARs (both in vitro and in vivo systems) were mostly based on hydrophobicity, pointing to an aspecific mechanism of action much simpler than that for carcinogenicity and mutagenicity. The oxidation of the amines (first step in the main metabolic pathway leading to carcinogenic and mutagenic species) had identical QSARs in both enzymatic and physical-chemical systems, thus providing evidence for the link between simple chemical reactions and those in biological systems. The results show that it is possible to generate mechanistically and statistically sound QSAR models for rodent carcinogenicity, and indirectly that the rodent bioassay is a reliable source of good quality data.

Lag-phase duration (LPD) and growth rate (GR) values were calculated from experimental data obtained using a previously described protocol (S. C. Ingham, M. A. Fanslau, G. M. Burnham, B. H. Ingham, J. P. Norback, and D. W. Schaffner, J. Food Prot. 70:1445-1456, 2007). These values were used to develop an interval accumulation-based tool designated THERM (temperature history evaluation for raw meats) for predicting growth or no growth of Salmonella serovars, Escherichia coli O157:H7, and Staphylococcus aureus in temperature-abused raw sausage. Data (time-temperature and pathogen log CFU per gram) were obtained from six inoculation experiments with Salmonella, E. coli O157:H7, and S. aureus in three raw pork sausage products stored under different temperature abuse conditions. The time-temperature history from each experiment was entered into THERM to predict pathogen growth. Predicted and experimental results were described as growth (&gt; 0.3 log increase in CFU) or no growth (&lt; ...

The genus Salmonella contains two species, S. bongori and S. enterica. Compared to the well-studied S. enterica there is a marked lack of information regarding the genetic makeup and diversity of S. bongori. S. bongori has been found predominantly associated with cold-blooded animals, but it can infect humans. To define the phylogeny of this species, and compare it to S. enterica, we have sequenced 28 isolates representing most of the known diversity of S. bongori. This cross-species analysis allowed us to confidently differentiate ancestral functions from those acquired following speciation, which include both metabolic and virulence-associated capacities. We show that, although S. bongori inherited a basic set of Salmonella common virulence functions, it has subsequently elaborated on this in a different direction to S. enterica. It is an established feature of S. enterica evolution that the acquisition of the type III secretion systems (T3SS-1 and T3SS-2) has been followed by the sequential acquisition of genes encoding secreted targets, termed effectors proteins. We show that this is also true of S. bongori, which has acquired an array of novel effector proteins (sboA-L). All but two of these effectors have no significant S. enterica homologues and instead are highly similar to those found in enteropathogenic Escherichia coli (EPEC). Remarkably, SboH is found to be a chimeric effector protein, encoded by a fusion of the T3SS-1 effector gene sopA and a gene highly similar to the EPEC effector nleH from enteropathogenic E. coli. We demonstrate that representatives of these new effectors are translocated and that SboH, similarly to NleH, blocks intrinsic apoptotic pathways while being targeted to the mitochondria by the SopA part of the fusion. This work suggests that S. bongori has inherited the ancestral Salmonella virulence gene set, but has adapted by incorporating virulence determinants that resemble those employed by EPEC.

Between 1995 and 2000, a prospective survey was undertaken to investigate the levels of contamination of raw retail chickens (n=1127) with salmonella and campylobacter. The levels of contamination over the 6-year period were 11% (95% CI±6·5%) for salmonella, and 57% (95% CI±9·5%) for campylobacter. S. Bredeney (20%) and S. Enteritidis (18%) were the dominant serovars. Although salmonella contamination was higher than in an earlier survey we conducted (7%), since 1998 it has declined to 6%. Many S. Enteritidis isolates (43%) were associated with one large integrated poultry organization that appears to have successfully managed the contamination, and the serovar has not been isolated since 1998. Contamination ranged from 0 to 44% between different producers. There was no significant difference between producers contributing large and small numbers of samples, although some small producers had much poorer contamination rates than others. S. Bareilly, S. Bredeney, S. Enteritidis and S....

Phenolic compounds present in berries selectively inhibit the growth of human gastrointestinal pathogens. Especially cranberry, cloudberry, raspberry, strawberry and bilberry possess clear antimicrobial effects against e.g. salmonella and staphylococcus. Complex phenolic polymers, such as ellagitannins, are strong antibacterial agents present in cloudberry, raspberry and strawberry. Berry phenolics seem to affect the growth of different bacterial species with different mechanisms. Adherence of bacteria to epithelial surfaces is a prerequisite for colonization and infection of many pathogens. Antimicrobial activity of berries may also be related to antiadherence activity of the berries. Utilization of enzymes in berry processing increases the amount of phenolics and antimicrobial activity of the berry products. Antimicrobial berry compounds are likely to have many important applications in the future as natural antimicrobial agents for food industry as well as for medicine.

Attenuated salmonella have been reported to be capable of both selectively growing in tumors and expressing exogenous genes for tumor-targeted therapy. As 6-methoxypurine 2′ ′ ′ ′-deoxyriboside (MoPdR) is similar to 6-methylpurine 2′ ′ ′ ′-deoxyriboside in structure, we aimed to evaluate the antitumoral effect of the Escherichia coli purine nucleoside phosphorylase (ePNP) gene, using an attenuated salmonella-mediated delivery system, in combination with MoPdR. A novel mutant serovar Typhimurium (SC36) was used to carry the pEGFP-C1-ePNP vector that contains an enhanced green fluorescent protein and an ePNP gene under the control of the cytomegalovirus promoter. The function of the ePNP expression vector was confirmed in vitro using the enzymic conversion of MoPdR into methoxypurine. We also observed a high bystander effect induced by the ePNP/MoPdR system with a very low proportion (1%) of ePNP-positive cells and 5 µ µ µ µg/mL MoPdR, although the growth of parental cells was affected appreciably by MoPdR. The killing effect and increased apoptosis induced by SC36 carrying the ePNP expression vector (SC/ePNP) were detected by cytotoxicity assay and propidium iodide staining flow cytometry analysis, in combination with MoPdR. SC/ePNP was given orally to mice bearing mammary carcinomas, and its antitumor effect was evaluated. SC/ ePNP plus MoPdR significantly inhibited tumor growth by approximately 86.6-88.7% and prolonged the survival of tumorhosting mice. Our data support the view that MoPdR combined with the ePNP gene could be used in gene-directed enzyme prodrug therapy. Attenuated salmonella could be a promising strategy to improve ePNP/MoPdR bystander killing due to its preferential accumulation and anticancer activity in tumors. (Cancer Sci 2008; 99: 1172-1179) Bruce A.. A novel purine-auxotrophic mutant SC36 (his G aro A cys pur I) with a low residual virulence was gained by diethyl sulfate mutagenesis of SL3261, as previously described. Bacterial strains were routinely grown at 37°C in Luria broth (LB) or agar supplemented with kanamycin (50 µg/mL). pEGFP-C1 and pEGFP-C1-ePNP were first transformed into LB5000 using electrotransformation in cuvettes (0.2 cm electrode gap; Eppendorf) with a single pulse of 12.5 kV/cm (2.5 kV, 200 Ω, 25 µF). After amplification of the colony, the plasmids were extracted from the transferred LB5000 (3S Spin Plasmid Miniprep Kit V3.1; Shanghai Shenergy Biocolors Bioscience & Technology Co. Ltd.) then introduced into SC36 (as carried out for LB5000) to generate SC/pEGFP and SC/ePNP. Cells, cell culture, and bacterial infection. Murine mammary carcinoma 4T1 cell lines were obtained from Shanghai No.1 People's Branch Hospital (China). The cells (10 5 cells/well) were cultured in 12-well plates overnight in antibiotic-free RPMI-1640 media (Gibco BRL) in a 5% CO 2 atmosphere at 37°C. Bacteria (SC/pEGFP or SC/ePNP) were shaken in LB broth with kanamycin (50 µg/mL) overnight at 37°C to reach the late logarithmic phase of growth (OD 600 of approximately 4) and suspended in antibiotic-free media. Then 2.5 × 10 7 c.f.u. of bacteria (at a multiplicity of infection of 1:250) were directly added into 12-well plates and co-incubated with tumor cells for 3 h. Subsequently, the cells were washed three times with phosphate-buffered saline (PBS) and replenished with complete media (containing 100 U/mL penicillin and 100 µg/mL streptomycin) and further cultured for 1 or 2 days. The infected cells were collected and some of them were used to monitor the gene expression by reverse transcription (RT)-PCR (AccessQuick;

In 2004/05, all European Union member states were required to carry out standardised prevalence surveys to establish the baseline prevalence of Salmonella in commercial laying flocks. As part of the survey in Great Britain, additional data were collected from 380 of the enrolled laying hen holdings to investigate risk factors for Salmonella at farm level. Stratified, simple random sampling was used to select holdings from which dust and boot swab samples were collected and tested for Salmonella using a modification of ISO 6579:2002. Using a multivariable logistic model weighted to account for the survey design, several factors significantly associated with Salmonella and Salmonella Enteritidis status were identified. Larger holdings (≥30,000 birds) were found to be at higher risk of Salmonella odds ratio [OR] 4.79, P=0.025), while vaccination (OR 0.28, P=0.013), providing foot dips with brushes (OR 0.27, P=0.042), washing and disinfecting the house at depopulation (OR 0.19, P=0.003), having a clean car park away from house (OR 0.14, P=0.001), using an independent (OR 0.19, P=0.007) or other non-company (OR 0.40, P=0.049) source of feed, being over 1 km from the nearest neighbouring farm (OR 0.45, P=0.021) and the presence of cats and dogs on the farm (OR 0.26, P=0.002) or on contiguous farms (OR 0.44, P=0.030) reduced the risk of any Salmonella serovars being present. Factors found to be associated specifically with an increased risk of S Enteritidis infection included holding size (OR 14.88, P=0.001) and frequent sightings of rats (OR 8.17, P<0.001) or mice (OR 5.78, P=0.006). Non-caged systems (OR 0.14, P=0.002), vaccination (OR 0.08, P=0.001), the use of a non-company feed source (OR 0.11, P=0.003), running the site as all-in/all-out (OR 0.06, P<0.001) and the presence of cats and dogs on the farm (OR 0.14, P=0.002) were associated with a reduced risk.

Biological nanofactories, which are engineered to contain modules that can target, sense and synthesize molecules, can trigger communication between different bacterial populations. These communications influence biofilm formation 1,2 , virulence 3,4 , bioluminescence 5,6 and many other bacterial functions 7,8 in a process called quorum sensing 9 . Here, we show the assembly of a nanofactory that can trigger a bacterial quorum sensing response in the absence of native quorum molecules. The nanofactory comprises an antibody (for targeting) and a fusion protein that produces quorum molecules when bound to the targeted bacterium. Our nanofactory selectively targets the appropriate bacteria and triggers a quorum sensing response when added to two populations of bacteria. The nanofactories also trigger communication between two bacterial populations that are otherwise non-communicating. We envision the use of these nanofactories in generating new antimicrobial treatments that target the communication networks of bacteria rather than their viability.

Significant effort has been targeted at reducing the risk of pathogens in U.S. beef products since the mid-1990s. These efforts were focused on Escherichia coli O157:H7 after it was declared an adulterant in ground beef or its components. Post-harvest interventions applied to hides and carcasses by beef processors resulted in significant progress. Effective pre-harvest approaches proved hard to identify and implement. Six additional pathogenic E. coli serogroups were made adulterants in some beef products in 2012 and discussion regarding Salmonella is ongoing. Success to date has resulted from the combination of regulatory, research, and industry efforts to reduce the presence of pathogens in beef.

This study was conducted to determine the occurrence and antimicrobial resistance of Salmonella serotypes isolates from feces, feed and broiler litter in poultry broilers in western Paraná between 2006 and 2010. The antigenic characterization and identification of serotypes confirmed 118 samples of Salmonella spp., belonging to 38 different serotypes. The most common serotypes identified were S. enteritidis (16.1%), S. heidelberg (5.9%), S. typhimurium (5.9%), S. hadar (5.0%), S. albany (4.2%), S. enterica (4.2) and S. saintpaul (4.2%). The serotypes of Salmonella spp. isolates were examined for resistance against 13 antibiotics using the disc diffusion method. Thirty-six samples (30.5%) were susceptible to all antimicrobials, and among the 82 resistant strains, there were 25 different resistance patterns. Serotypes' multi-resistant to streptomycin, nalidixic acid and tetracycline (20.7%), nalidixic acid (13.4%) and nalidixic acid and tetracycline (11.0%) were found at higher frequency. The results revealed high prevalence of Salmonella spp. mainly S. enteritidis (16.1%) in aviary environment and percentage of strains' resistant to conventional antibiotics.

Bats are one of the most widely distributed mammals in the world, and they are reservoirs or carriers of several zoonoses. Bats were trapped in 27 geographic locations across Trinidad and Tobago, and following euthanasia, gastrointestinal tracts were aseptically removed. Contents were subjected to bacteriologic analysis to detect Salmonella spp., Escherichia coli, and Campylobacter spp. Isolates of Salmonella were serotyped, and E. coli isolates were screened for O157 strains and antimicrobial sensitivity to eight antimicrobial agents; phenotypic characteristics also were determined. Of 377 tested bats, representing 12 species, four bats (1.1%) were positive for Samonella spp, 49 (13.0%) were positive for E. coli, and no bats were positive for E. coli O157 strain or Campylobacter spp. Isolated serotypes of Salmonella included Rubislaw and Molade, both from Noctilio leporinus, a fish-eating bat, Caracas recovered from Molossus major, and Salmonella Group I from Molossus ater, both insect-eating bats. Of the 49 isolates of E. coli tested, 40 (82%) exhibited resistance to one or more antimicrobial agents, and the prevalence of resistant strains was comparatively high to erythromycin (61%) and streptomycin (27%) but lower to gentamycin (0%) and sulphamethozaxole/trimethoprim (2%).

Abstract: Salmonella is one of the leading causes of foodborne illness in countries around the world. Treatment of Salmonella infections, in both animals and humans has become more difficult with the emergence of multidrug-resistant (MDR) Salmonella strains. Foodborne infections and outbreaks with MDR Salmonella are also increasingly reported. To better monitor and control the spread of MDR Salmonella, it is important to understand the mechanisms responsible for drug resistance and how drug resistance is transmitted to ...

The presence of Salmonella, Listeria monocytogenes, and Escherichia coli O157:H7 in ready-to-eat (RTE) meat products is considered a major concern for food control authorities worldwide. The aims of this study were to determine (i) the prevalence of Salmonella, L. monocytogenes, and E. coli O157:H7 in Mediterranean RTE chicken and beef (CB) products sold in Jordanian restaurants and (ii) the susceptibility of the isolates to antibiotics. A total of 1,028 samples of various types of RTE CB products (550 RTE chicken and 478 RTE beef products) were analyzed by methods described by the International Organization for Standardization followed by molecular confirmation of the isolates. The VITEK2 automated system was used for testing antibiotic susceptibility of the isolates. The overall prevalence of Salmonella serovars in RTE CB products was 0.5%, with 0.8 and 0.2% in RTE chicken and RTE beef, respectively. The overall prevalence of L. monocytogenes in RTE CB products was 2%, with 2.7 and 1.5% in RTE chicken and RTE beef products, respectively. E. coli O157:H7 was not isolated from any of the tested samples. Multidrug-resistant Salmonella and L. monocytogenes isolates were found. The majority of Salmonella isolates were sensitive to most of the tested antibiotics, and all of the isolates were resistant to more than one antibiotic. Similarly, more than 85% of L. monocytogenes isolates were sensitive to nine antibiotics, and the majority of L. monocytogenes isolates were resistant to fosfomycin and oxacillin.

A recent European Union Directive required member states to put monitoring and control programmes in place, of which vaccination is a central component. Live Salmonella vaccines generally confer better protection than killed vaccines, because the former stimulate both cell-mediated and humoral immunity. Administering Salmonella bacteria orally to newly hatched chickens results in extensive gut colonization and a strong adaptive immune stimulus but broiler chickens are immunologically immature. However, colonization exerts a variety of rapid (within 24 h) protective effects. These include specific colonization-inhibition (competitive exclusion) in which the protective bacteria exert a profound resistance to establishment and colonization by other related bacteria. This is thought to be primarily a metabolic attribute of the vaccinating bacteria but may also involve competition for attachment sites. The presence of large numbers of bacteria originating from a live Salmonella vaccine in the intestine can also induce infiltration of polymorphonuclear cells into the intestinal wall, which confers resistance to invasion and systemic spread by virulent Salmonella strains. This opens new perspectives for vaccine usage in broilers, layers and breeding poultry but also in other animals which show increased susceptibility to infection because of their young age or for other reasons, such as oral chemoprophylaxis or chemotherapy, where the lack of established normal gut flora is an issue. We recommend that all live vaccines considered for oral administration should be tested for their ability to induce the two protective effects described above. Further developments in live Salmonella vaccines are, however, currently hindered by fears associated with the use and release of live vaccines which may be genetically modified.

Aerobic mesophilic counts (AMC), coliform (CC) and coliform resuscitation counts (CRCs) were obtained by swabbing 50 cm 2 areas at three sites (ham, belly and neck) on pig carcasses, after each of seven stages of the slaughter/dressing process (bleeding, scalding, dehairing, singeing, polishing, evisceration and chilling). In most cases, there were no statistical differences ( P>0.05) among the counts derived by these three methods. Reductions in counts at individual sites were observed after scalding (3.5 log 10 cfu cm À 2 ), and singeing (2.5 log 10 cfu cm À 2 ). Increases in counts at individual sites were observed after dehairing (2.0 log 10 cfu cm À 2 ) and polishing (1.5 log 10 cfu cm À 2 ). The incidence of Salmonella on pig carcasses was also obtained by swabbing the outside surfaces of 100 half carcasses. Information on the incidence of Salmonella in scald tank water (108 samples) was also investigated. Carcass swabs and scald tank water were examined for the presence of Salmonella using standard enrichment methods. Salmonella were detected on 31% of carcasses immediately after bleeding, 7% of carcasses immediately after dehairing and evisceration, and 1% of carcasses immediately after scalding. Serovars included Salmonella Typhimurium, Salmonella Hadar, Salmonella Infantis and Salmonella Derby. No Salmonella were recovered from samples of scald tank water. The impact of pig slaughter/dressing processes on carcass microbiology and their potential use as critical control points (CCPs) during pork production are discussed. D

Salmonella is a key human pathogen worldwide, most often associated with food poisoning incidences. There is a small number of predominant serotypes found in human cases. The role of exposure in the epidemiology of Salmonella can be explained using dose-response assessment both for infection and acute enteric illness. Dose-response studies are traditionally based on human challenge experiments but an alternative is to use outbreak data. Such data were collected from the published literature which included estimates of the dose ingested and the attack rate. Separate dose-response models for infection and illness given infection were fitted using a multi-level statistical framework. These models incorporated serotype and susceptibility as categorical covariates, and adjusted for heterogeneity in exposure. The results indicate that both the risk of infection and the risk of illness given infection increase with dose. The dose-response model incorporating data from all outbreaks had an infection ID50 of 7 CFU's and illness ID50 of 36 CFUs. This is indicative of much higher infectivity and pathogenicity compared with feeding studies of healthy human volunteers with laboratory adapted strains. No differences were found in the outbreak models between serotypes and susceptibility categories. However, for serotypes other than S. Enteritidis or S. Typhimurium, results indicate that a minor proportion of individuals exposed will not fall ill even at high doses. The dose-response relations indicate that outbreaks are associated with higher doses making it more likely to have a higher attack rate. Applications of the dose-response model in outbreak situations where either dose or attack rate is missing were successfully used to clarify the epidemiology. Finally, the dose-response models described here can be readily used in quantitative microbiological risk assessment to predict human infection and illness rates. A simple Excel spreadsheet implementing the model has been prepared and is available from the authors.

Typhoid fever is a systemic infection caused by the bacterium Salmonella enterica subspecies enterica serotype typhi, a foremost public health predicament in developing countries. This study investigated hepatotoxicological changes associated with Salmonella typhi infection in Wistar rats and the potential of ethanol root extract of Millettia aboensis (EREMA) to reverse these changes. 51 animals were divided into six groups: group 1 was normal control with no treatment but were given feed and water ad libitum, group 2 was infected with Salmonella typhi without treatment (negative control), group 3, 4 and 5 were Salmonella typhi infected and treated with 100mg/kg, 200mg/kg and 400mg/kg of the extract respectively, and group 6 was infected and treated with 7.14mg/kg of ciprofloxacin. The animals were inoculated with a single infectious dose of Salmonella typhi bacterium (2.0 x 10 8 cfu/ml) and were subsequently treated with the graded doses of the extract and 7.14mg/kg of ciprofloxacin for a period of fifteen days. The rats were humanely sacrificed using diethyl ether anesthesia and blood samples taken for liver function investigation including [aspartate aminotransferase (AST) alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin (TB), Albumin, conjugate bilirubin (CB) and total protein (TP)] and liver harvested and processed for histological assessment. Inoculation with S. typhi caused significant increase in all the liver function parameters and different degrees of damages to the liver cells. These were all reversed on treatment with ethanol root extract of Millettia aboensis. Thus the extract exhibited both anti-Salmonella typhi as well as hepato-curative potentials on the Kuffer cells.

Food-borne salmonellosis continues to be a major public health concern, and contamination with Salmonella spp. in pre-harvest animal production is considered a primary contributor to this problem. Animal feeds can easily become contaminated during primary production, feed mixing and processing as well as during feeding. Consequently, monitoring and surveillance of feeds and feed ingredients for Salmonella spp. contamination may be useful or necessary in the prevention and control of this organism. Cultural and immunological detection methods for salmonellae have been used or suggested as possible approaches for use in animal feeds. Cultural methods remain advantageous owing to their ability to detect viable bacterial cells, while immunological methods have the capability of detecting nonculturable bacterial cells. Advancements and improvements in both methodologies offer opportunities for eventual routine use of these detection technologies in animal feed assays.

Consumption of minimally-processed, or fresh-cut, fruit and vegetables has rapidly increased in recent years, but there have also been several reported outbreaks associated with the consumption of these products. Sodium hypochlorite is currently the most widespread disinfectant used by fresh-cut industries. Neutral electrolyzed water (NEW) is a novel disinfection system that could represent an alternative to sodium hypochlorite. The aim of the study was to determine whether NEW could replace sodium hypochlorite in the fresh-cut produce industry. The effects of NEW, applied in different concentrations, at different treatment temperatures and for different times, in the reduction of the foodborne pathogens Salmonella, Listeria monocytogenes and Escherichia coli O157:H7 and against the spoilage bacterium Erwinia carotovora were tested in lettuce. Lettuce was artificially inoculated by dipping it in a suspension of the studied pathogens at 10 8 , 10 7 or 10 5 cfu ml −1 , depending on the assay. The NEW treatment was always compared with washing with deionized water and with a standard hypochlorite treatment. The effect of inoculum size was also studied. Finally, the effect of NEW on the indigenous microbiota of different packaged fresh-cut products was also determined. The bactericidal activity of diluted NEW (containing approximately 50 ppm of free chlorine, pH 8.60) against E. coli O157:H7, Salmonella, L. innocua and E. carotovora on lettuce was similar to that of chlorinated water (120 ppm of free chlorine) with reductions of 1-2 log units. There were generally no significant differences when treating lettuce with NEW for 1 and 3 min. Neither inoculation dose (10 7 or 10 5 cfu ml −1 ) influenced the bacterial reduction achieved. Treating freshcut lettuce, carrot, endive, corn salad and 'Four seasons' salad with NEW 1:5 (containing about 50 ppm of free chlorine) was equally effective as applying chlorinated water at 120 ppm. Microbial reduction depended on the vegetable tested: NEW and sodium hypochlorite treatments were more effective on carrot and endive than on iceberg lettuce, 'Four seasons' salad and corn salad. The reductions of indigenous microbiota were smaller than those obtained with the artificially inoculated bacteria tested (0.5-1.2 log reduction). NEW seems to be a promising disinfection method as it would allow to reduce the amount of free chlorine used for the disinfection of fresh-cut produce by the food industry, as the same microbial reduction as sodium hypochlorite is obtained. This would constitute a safer, 'in situ', and easier to handle way of ensuring food safety.

A study was carried out to estimate the proportion of diseases due to milk and milk products among food-borne diseases recorded in France and in other countries since 1980. Particular attention was given to whether the milk involved was heat-treated or not. Four etiologic agents were considered: Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and pathogenic Escherichia coli. An overview of food-borne disease annual reports from seven countries indicated that milk and milk products were implicated in 1-5% of the total bacterial outbreaks; however, details about the type of product and milk involved were usually not provided. When considering 60 outbreaks and four single cases described in the literature and implicating milk and milk products, confirmed or suspected food vehicles were distributed as follows: milk, 39.1%, cheese, 53.1%, other milk products, 7.8%. Overall, 32.8% of the food vehicles were made from pasteurised milk; 37.5% from raw milk; 10.9% from milk stated as &amp;quot;unpasteurised&amp;quot;; and 18.8% from unspecified milk. Salmonella spp. were responsible for 29 outbreaks, L. monocytogenes for 10 outbreaks and four well-documented single cases, pathogenic E. coli for 11 outbreaks, and S. aureus for 10 outbreaks. Analysis of unpublished data about food-borne disease outbreaks, listeriosis excluded, collected by the coordinator of the French surveillance system from 1992 to 1997, revealed 69 documented outbreaks for which milk and milk products were confirmed as the vehicle by the isolation of the etiologic agent. The food vehicles were distributed as follows: milk, 10%; cheese, 87%; others, 3%. UHT milk accounted for 1.5%, raw milk and raw milk products for 48%, and milk and milk products from unspecified milk for 50.5% of the 69 outbreaks. S. aureus was by far the most frequent pathogen associated with these outbreaks (85.5% of the outbreaks), followed by Salmonella (10.1%). This study demonstrates the limitations of the surveillance systems and the difficulties in estimating the contribution of milk and milk products to food-borne diseases. In particular, it was not possible to find out in many outbreaks what heat treatment, if any, the milk had undergone.

Green, hydrophobic device for controlled transdermal release of diclofenac sodium was designed from in situ nanosilica/acrylic acid grafted guargum membranes. Best grafting condition was assigned and nanocomposites were formed in situ using varying proportions of aqueous nanosilica sol. Nanocomposite/drug conjugates were formed by bringing down the medium pH from 9.0 to 7.0. The conjugates were characterized through infrared and solid state NMR spectroscopy, electron microscopy, hydro-swelling, surface contact angle, viscometry and biocompatibility. Most balanced property was exhibited by the membrane containing 1 wt% nanosilica. It also had shown the highest encapsulation efficacy vis-à-vis slowest release as compared to others during experimentation in a Franz diffusion cell.

Background and Aim: Pigeon rearing has been gaining popularity for recent years. They are reared remarkably very close to the house of the owner. This activity, therefore, may pose potential threats for humans as well as other animals as pigeons may carry and spread different pathogens including drug-resistant bacteria. This study was conducted to explore the prevalence of Escherichia coli and Salmonella spp. as well as their antibiogram profile along with an association analysis. Materials and Methods: Forty swab samples were collected from 20 pigeons during the study. E. coli and Salmonella spp. were isolated and identified on various types of agars, including MacConkey, Eosin methylene blue, Brilliant green, and Salmonella-Shigella agar. Biochemical tests such as the carbohydrate fermentation test, the triple sugar iron agar slant reaction, the indole test, the methyl red test, the catalase test, as well as the Voges–Proskauer test were also performed. Besides, the presence of E....

M. ZAMFIR, R. CALLEWAERT, P.C. CORNEA, L. SAVU, I. VATAFU and L. DE VUYST.1999.Lactobacillus acidophilus IBB 801 produces a small bacteriocin, designated acidophilin 801, with an estimated molecular mass of less than 6·5 kDa. It displays a narrow inhibitory spectrum (only related lactobacilli but including the Gram-negative pathogenic bacteria Escherichia coli Row and Salmonella panama 1467) with a bactericidal activity. The antimicrobial activity of cell-free culture supernatant fluid was insensitive to catalase but sensitive to proteolytic enzymes such as trypsin, proteinase K and pronase, heat-stable (30 min at 121 °C), and maintained in a wide pH range. The proteinaceous compound was isolated from cell-free culture supernatant fluid and purified. Crude bacteriocin was isolated as a floating pellicle after ammonium sulphate precipitation (40% saturation) and partially purified by extraction/precipitation with chloroform/methanol (2/1, v/v). Further purification to homogeneity was performed by reversed phase Fast Performance Liquid Chromatography. The amino acid composition was determined. Amino acid sequencing revealed that the N-terminal end was blocked.

Background: Salmonellosis is one of the most dangerous diseases that is caused by Salmonella agents and has a wide spectrum of clinical manifestations - from asymptomatic to severe septic forms. In the majority of Salmonella infection cases, the enterica subspecies serovars are isolated from animals and humans. According to the FAO, 20% of poultry products in the world are contaminated with salmonella. Every year 21 million cases of typhoid fever are registered wherein 216 thousand are lethal. Traditional microbiological methods for Salmonella typing (cultivation) are usually time-consuming. This necessitates the development of modern methodology for food safety. Goal: Development of a multiplex PCR protocol enabling identification of Salmonella spp. and typing of Enterisa Salmonella Enteritidis, Salmonella Enterisa Typhimurium, Salmonella Typhi, Salmonella Dublin, and Salmonella Gallinarum. Methods & Materials: For amplification the following primers were used: Salmonella spp.: Salm3-Salm4 (Ferretti, 2001); Salmonella enteritidis: SentF-SentR (Agron, 2001); Salmonella typhimurium: StypF-StypR (O’Regan, 2008); Salmonella Typhi: StyphiF-StyphiR (Kumar, 2008); Salmonella Dublin: SdubF-SdubR; Salmonella Gallinarum: SgalF-SgalR (Akiba, 2011). Optimization of multiplex PCR protocol was performed according to Elnifro (Elnifro, 2000). Results: To determine the optimal PCR primer's annealing temperature the assays were performed at 58◦C, 60◦C, 63◦C, and 65◦C. The optimal amplification mode was determined to be as follows: Initial denaturation - 94◦C-2 min; Denaturation - 94◦C-45s; Annealing - 63◦C-45s; Extension - 72◦C-60s (40 cycles); Final extension - 72◦C-5 min. The optimal composition of the reaction mixture for multiplex PCR was: 10×DreamTaq Buffer-2,5ul, dNTP Mix, 2mM each-2,5ul, 25mM MgCl2-0,5ul, Primers 20pM, Template DNA-5,0ul, DremTaq DNA Polymerase-2,0ul Water, nuclease-free-3,5ul. The resulting protocol allowed for the detection of Salmonella spp. DNA in the samples, as well as the simultaneous typing of Salmonella Enterica Enteritidis, Salmonella Enterica Typhimurium, Salmonella Typhi, Salmonella Dublin, and Salmonella Gallinarum.The simultaneous amplification of all 6 expected fragments occurred in the multiplex PCR. Conclusion: The developed protocol is promising for the biological control of food safety, as well as in routine investigations.

To ensure that the residents are kept as safe as possible from food poisoning and food-associated illness, by adopting the highest standards of food hygiene and food preparation. If food poisoning does occur, the organization will ensure that its staff is able to recognize the signs and symptoms do a full investigation and take corrective action.

Effects of mineral oil (MO) and 4 emulsions (prepared with different emulsifier types) of MO and chitosan solution (CH) at a fixed ratio of MO:CH = 25:75 as coating materials in preserving the internal quality of eggs were evaluated during 5 wk at 25 • C and 20 wk at 4 • C. Generally, as storage time increased, Haugh unit and yolk index values decreased whereas weight loss increased. However, MO and/or 4 emulsion coatings minimized the weight loss (<1.5%) and preserved the albumen and yolk quality of eggs (with the final B grade) for at least 3 wk longer than those observed for noncoated eggs at 25 • C. At 4 • C, all coated eggs changed from AA to A grade after 5 wk and they maintained this grade for 10 wk (5 wk longer than that of noncoated eggs). Although refrigeration (4 • C) alone could maintain the B grade of noncoated eggs for up to 20 wk, coating treatments were necessary to keep the weight loss below 2%. Compared with 4 • C, the increasing weight loss showed stronger negative correlation (P < 0.01) with the decreasing Haugh unit (-0.46 to -0.89) and yolk index (-0.36 to -0.89) at 25 • C. The emulsifier type used in this study generally did not affect the internal quality of eggs. Salmonella spp. detection was negative for all coated and noncoated eggs. This study demonstrated that MO and MO:CH emulsion coatings preserved the internal quality, prolonged the shelf-life, and minimized weight loss (<2%) of eggs.