In vitro characterization of intra-generic inhibition of growth in Salmonella typhimurium

The intra-generic inhibition of bacterial growth observed previously in vivo and in vitro with strains of Salmonella, Citrobacter and E. coli was studied in vitro using S. typhimurium strain F98. There was complete inhibition of multiplication of S. typhimurium when it was added to stationary-phase broth cultures of different Salmonella serotypes, but only partial inhibition when added to broth cultures of E. coli. The degree of inhibition between different mutants of F98 was affected by the numbers of bacteria of the inhibiting strain, but this was not the only factor, since exponential-phase bacterial cells were less inhibitory than stationary-phase cells. The inhibitory effect was produced at temperatures between 20°C and 40°C. The complete inhibition of growth observed between F98 mutants was abolished by ampicillin, rifampicin and streptomycin, but not by nalidixic acid. Inhibition was also prevented by separating the two cultures by a dialysis membrane. A Tnpho A Insertion mutant of F98 was produced which did not show inhibition in vitro but was still inhibitory in vivo. It is suggested that this complete inhibition of bacterial multiplication between organisms of the same genus, which is greater than that produced between organisms from different genera, is mediated by a cell surface protein.

The antibacterial effects for Salmonella Enteritidis phage type 4 of different chemical disinfectants and cleaning agents tested under different conditions

A selection of commercially available disinfectants, sanitizers and water sanitizers based on iodophor, quaternary ammonium compounds (QACs) and phenolic compounds were tested for their activity against a phage type 4 strain of Salmonella serotype Enteritidis in the presence of a variety of organic materials. In general the phenolic preparations were the most effective followed by the QACs and the iodophors. They were all inactivated to different degrees by chick fluff, chicken faeces, feed and wood shavings. The inactivation was greatest when Salmonella organisms were pre-dried in feed. Under these conditions formaldehyde and glutaraldehyde were still active. There was some evidence that induced resistance to stress conditions including culture at 42°C and anaerobic culture increased resistance to one of the water sanitizers.

Salmonella em carcaças de frango congeladas

Hundred and fifty frozen broiler carcasses of four commercial brands, purchased at retail stores for Salmonella research, were examined: 43 of the carcasses referred to each of the brands A, B, D and 21 of brand C. Thirty-two percent of the samples were found positive; 11 serotypes were identified as S. Agona, S. Anatum, S. Enteritidis, S. Hadar, S. Havana, S. Mbandaka, S. Montevideo, S. Ouakam, S. Poona, S. Schwarzengrund and S.14, 5, 12:-. Antibiogram testing of the isolated strains showed 100% resistance to ampicilin, 75.0% to cefhalotin, 52.1% to cephoxitin, 22.9% to tobramicin, 6.2% to polimixin B and to tetracyclines, 4.2% to gentamicin, and 2.1% to netilmicin, to aztreonam and to amicacin. All strains showed total sensibility to chloramphenicol and to sulfazotrim.

Experimental Salmonella enterica serovar Pullorum infection in two commercial varieties of laying hens

An experiment was carried out to investigate the biology of Salmonella Pullorum in two varieties of laying hens, from 5 days of age up to 9 months. One variety was resistant to systemic salmonellosis (light layers producing white eggs) and the other was considered susceptible (brown layers producing brown eggs). The brown birds were more affected by the infection, showing signs of clinical disease in the first month of life. Later, these signs disappeared, but postmortem examination revealed persistent gross pathological changes in the liver, spleen, heart and ovary. The rapid agglutination test detected reactors throughout the experiment, with the strongest agglutination from 1 to 7 months post-infection. S. Pullorum was isolated from some of the organs and the eggs laid throughout the experiment. The relationship between white birds and S. Pullorum was less intense, and there were no noticeable signs of disease. There were few gross pathological changes, and the bacteria were isolated infrequently and only for a brief period after infection, although contaminated eggs were laid by these birds. The strongest serological response in the white chickens occurred between the second and the fifth month post-infection.

Avaliação do extrato de Momordica charantia em Salmonella typhimurium: Mutagenicidade e antimutagenicidade

In the last years some natural products has been described as supressors of the mutagenic process in bacteria, the antimutagenics. The literature reference that in most of the countries, the population makes use of medicinal plants. The plant Momordica charantia (Cucurbitaceae) is original from Africa being used popularly as purgative, antirheumatic and for skin problems, burns and hemorrhoids. The present work had as objective to evaluate the mutagenic and antimutagenic activities of the ethanolic extract of M. charantia in Salmonella/microsome assays using TA100, TA98 and TA102 strains. It was verified that the extract did not present mutagenic activity when evaluated in different concentrations (0.64, 1.27, 2.55 and 3.84 mg/plate) but acted as antimutagenic agent against the mutations induced by the sodium azide (TA100,-S9), 4-nitro-phenylenediamine (TA98, -S9), daunomycin (TA102, +S9) 2-anthramine (TA100 and TA98, +S9) and 2-aminofluorene (TA102, +S9). When the metabolic activation (+S9) was used, the percentage of inhibition of the mutagenicity varied in the range of 31%-96%, while in absence of metabolizing system (-S9), the maximum percentage of inhibition of the mutagenicity was 44%. In that way, we can conclude that the metabolites found in the extract has potential to protect the genetic material against the damages induced by different chemical agents.

Avaliação da atividade mutagênica do resíduo sólido de uma fábrica de confecções de meias e lingerie em ensaios com Salmonella typhimurium

Cancer is one of the most hazardous effects to human health caused by the exposition to chemical agents. The search for new technological solutions in the industrial field led to a rapid increase in the productive sector, causing the workers to be exposed to millions of potentially toxic agents, substances potentially harmful to health. This study presents the mutagenic activity of sweepings from a sock and lingerie factory in Araraquara-Brazil, assayed with Salmonella typhimurium. All the extracts from the factory had mutagenic on activity the YG1024 strain, which is extremely sensitive to detect the mutagenic activity of the arilhydroxilamines, nitroarenes and aromatic amines. The extracts were non-mutagenics for the strains TA100 and TA98. The analysis of the mutagenicity of industrial residues is highly important because employees that participate in the production are directly exposed to those agents, as well as to the environment where the garbage is deposited.

Effect of organic acids and probiotics on Salmonella enteritidis infection in broiler chickens

The effect of an organic acid mixture (OA) and a Lactobacillus-based probiotic culture on Salmonella enteritidis (SE) infection in broiler chicks was evaluated. In exp. 1, chicks were challenged by oral gavage with SE, held in chick boxes for 2 h and randomly assigned to either untreated control or continuous OA treatment in the drinking water. Crop and cecal tonsils were cultured at 48 h and 5 d post-challenge for recovery of SE. Recovery of SE in the crop and cecal tonsils at 48 h was significantly (p<0.05) lower in the OA treated group as compared to control chickens but not different at 5d. In exps.2 and 3, chicks were SE challenged, held in chick boxes for 2 h and randomly assigned to either untreated control, probiotic, OA, or probiotic+OA. After 24 or 48 h, crop and cecal tonsils were cultured for the presence or absence of SE. After 24 h, probiotic or probiotic+OA significantly reduced SE recovery from the crop as compared to controls. All treatments reduced SE recovery from the cecal tonsils at 24 h. While no significant differences were observed in SE recovery from crop at 48 h, SE recovery from probiotic and or probiotic+OA groups was significantly lower than the controls in the cecal tonsils. These data suggest that combination treatment with the selected OA and Lactobacillus-based probiotic culture is more effective than individual treatment for Salmonella reduction in chicks. © Asian Network for Scientific Information, 2007.

Effects of propolis from Brazil and Bulgaria on Salmonella serovars

Propolis shows biological properties such as antibacterial action. This bee product has a complex chemical composition, which depends on the local flora where it is produced. Salmonella serovars are responsible for human diseases that range from localized gastroenteritis to systemic infections. The aim of the present study was to investigate the susceptibility of Salmonella strains, isolated from food and infectious processes, to the antibacterial action of Brazilian and Bulgarian propolis, as well as to determine the behavior of these bacteria, according to the incubation period, in medium plus propolis. Dilution of ethanolic extract of propolis in agar was the used method. Brazilian and Bulgarian propolis showed an antibacterial action against all Salmonella serovars. The minimal inhibitory concentrations (MIC) of propolis were similar, although they were collected in different geographic regions. Salmonella typhimurium, isolated from human infection, was more resistant to propolis than Salmonella enteritidis.

Modulatory effect of Byrsonima basiloba extracts on the mutagenicity of certain direct and indirect-acting mutagens in Salmonella typhimurium assays

Byrsonima basiloba A. Juss. species is a native arboreal type from the Brazilian cerrado (tropical American savanna), and the local population uses it to treat diseases, such as diarrhea and gastric ulcer. It belongs to the Malpighiaceae family, and it is commonly known as murici. Considering the popular use of B. basiloba derivatives and the lack of pharmacological potential studies regarding this vegetal species, the mutagenic and antimutagenic effect of methanol (MeOH) and chloroform extracts were evaluated by the Ames test, using strains TA97a, TA98, TA100, and TA102 of Salmonella typhimurium. No mutagenic activity was observed in any of the extracts. To evaluate the antimutagenic potential, direct and indirect mutagenic agents were used: 4 nitro-o-phenylenediamine, sodium azide, mitomycin C, aflatoxin B1, benzo[a]pyrene, and hydrogen peroxide. Both the extracts evaluated showed antimutagenic activity, but the highest value of inhibition level (89%) was obtained with the MeOH extract and strain TA100 in the presence of aflatoxin B1. Phytochemical analysis of the extracts revealed the presence of n-alkanes, lupeol, ursolic and oleanolic acid, (+)-catechin, quercetin-3-O-α-L-arabinopyranoside, gallic acid, methyl gallate, amentoflavone, quercetin, quercetin-3-O-(2″-O-galloyl)-β-D- galactopyranoside, and quercetin-3-O-(2″-O-galloyl)-α-L- arabinopyranoside. © 2008 Mary Ann Liebert, Inc.

Surto de salmonella enteritidis/enteridis em granja produtora de frango caipira na região sul do maranhão

The aim of this trial was to detect the agent that causes high mortality of chickens in a farm in the south of Maranhão, Brazil, as well as determining the infection source. Necropsy of the chickens was done and carried through bacteriological analyses of liver, intracardiac blood and chicken food. The samples taken from the heart blood, liver and initial chicken feed had presented characteristic colonies of Salmonella. These colonies had been submitted to the biochemical and serologic tests for evidence of the patogenicity. Salmonelosis is considered an important disease in the poultry keeping and can cause serious ambient and economic losses, beyond the problem of public health. This paper stands out the importance of a good sanitary handling and programs of control and prevention of illnesses in the animal breeding.

Pesquisa de Salmonella e das condições sanitárias em frangos e lingüiças comercializados na cidade de Botucatu

In the present investigation were evaluated the sanitary conditions of poultry and several types of sausages retailed in Botucatu, São Paulo, Brazil for the determination of the most probable number of coliforms at 45°C/g besides the research of Salmonella using traditional methodology and PCR. In order to do so, 50 samples of poultry and 75 of sausages were collected from nine different establishments in the city, in the period of April to November of 2006. Of the 50 samples of chicken meat, 35 (70%) were out of the microbiologic parameters, according to Brazilian Sanitary Resolution RDC no 12 of Anvisa (>104 coliforms at 45°C/g). In this Resolution, the research of Salmonella is not demanded, but 4 samples (8%) presented the pathogen using the traditional methodology. That presence was confirmed by PCR, which was also positive in another 23, in a total of 27 positive samples (54%). Among 75 samples of sausages, 30 (40%) were out of the allowed limits, with 7 positive samples for Salmonella, using traditional methodology. However, if we consider PCR test, the number of positive samples increases to 42 (56%). Adding this number to coliforms microbiological limits, 86.7% of the analyzed sausages were inappropriate for the consumption.

Experimental infection of commercial layers using a Salmonella enterica serovar Gallinarum strain: Leukogram and serum acute-phase protein concentrations

The aim of the present study was to evaluate white blood cell counts and serum protein profiles of commercial layers experimentally infected with Salmonella Gallinarum (SG) in order to better understand the pathophysiology of the disease caused by this bacterium. 180 five-day-old commercial layers were divided into 3 groups (G); G1 and G2 received 0.2 mL of inoculate containing 3.3x10 8 CFU or 3.3×10 5 CFU SG resistant to nalidix acid (Nal r)/mL, respectively, directly into their crops. G3 group did not receive the inoculum. Birds were sacrificed 24 hours before (T1) and 24 hours after the infection (T2), and three (T3), five (T4), seven (T5), and ten (T6) days after the administration of the inoculum. White blood cell counts were carried out in a Neubauer hemocytometer and in blood smears. Serum protein concentrations, including acute-phase proteins, were determined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Data were submitted to analysis of variance, and means were compared by Tukey's test (P <0.05). G1 and G2 groups presented higher leukocyte counts on T4 and T5, respectively, due to the increase of circulating lymphocytes and heterophils, with a significant difference relative to G3. In electrophoresis, an increase in the serum levels of ceruloplasmin, haptoglobin, and hemopexin and a decrease in transferrin, which are acute-phase proteins, was verified. IgA serum levels did not change; however, IgG concentration increased during the infection. In conclusion, the results provide information for the better understanding of the pathophysiology of fowl typhoid.

Participation of genes involved in the process of anaerobic respiration of infection in chickens by salmonella typhimurium

Intestinal pathogens are exposed to various stress conditions during their infectious cycle. Anaerobiosis, one of such hostile condition, is offered by the host within gut and intestinal lumen, where survival, multiplication and entry into intestinal epithelial cells are priority for the invasion of the pathogen. The fumarate reductase (frdABCD), dimethyl sulfoxide (DMSO)-trimethylamine N-oxide (TMAO) reductase (dmsABC), and nitrate reductase (narGHIJ) operons in Salmonella Typhimurium (STM) encode enzymes involved in anaerobic respiration to the electron acceptors fumarate, DMSO, TMAO, and nitrate, respectively. They are regulated in response to nitrate and oxygen availability and changes in cell growth rate. Vitamin B12 (cobalamin) is synthesized by Salmonella Typhimurium only under anaerobic growth conditions used as a cofactor in four known reactions. The deletion of cobS and cbiA genes prevent any form of cobalamin production. In the present study we evaluate the infection of birds by mutants of STM, with the anaerobic respiratory system committed by mutations in the genes: narG, napA, cobS, cbiA, frdA, dmsA, and torC. Virulence was assessed by oral inoculation of groups of one-day-old broilers with 0.1 mL of culture contained 10 8 colony forming units (CFU)/mL or diluted at 10 -3 and 10 -2 of strains mutants of Salmonella Typhimurium. Clinical signs and mortality were recorded over a period of 21 days. In general, the symptoms of chickens infected with the mutant strains were similar to those presenting by control birds. Except for STMNalr cbiA, all showed reduced capacity to cause mortality in comparison with the original strain. The mortality of group of chickens infected with STMNal r △narG, STMNal r △frdA, STMNal r △dmsA and STMNal r △cobS△cbiA showed significant decrease in mortality compared to control group (p<0.05).

Mutagenicidade de duas espécies do gěnero Alchornea avaliadas através de ensaios com Salmonella microssomo e teste do micronúcleo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)