Anderlise Borsoi

Effects of oxytocin microinjected into the central amygdaloid nucleus and bed nucleus of stria terminalis on maternal aggressive behavior in rats

The central effect of oxytocin (OT) on the aggressive behavior of lactating rats was studied. Female rats are more aggressive than nonlactating resident females, vigorously attacking conspecific intruder male or females. This behavior is considered important for pup protection against infanticide. The present work aimed to test the effects on maternal aggressive behavior of OT infused into the central amygdaloid nucleus (CeM) or bed nucleus of stria terminalis (BNST). The surgeries for bilateral cannula implantation were performed between the 2nd and 4th postpartum day. Three days after the surgery, saline or OT was infused and 5 min later a male intruder was placed in the home-cage and the behaviors were videotaped for 10 min. The frequency of the aggressive behaviors and the duration of locomotion during the aggressive behavior test were measured. The latency to retrieve the pups was also evaluated. The results showed that OT injected into CeM (10 and 20 ng/nucleus) decreased frequency of biting and frontal attack while in the BNST (10 and 20 ng/nucleus) decreased the frequency of biting. No significant change on retrieval activity was detected. OT in CeM and BNST has an inhibitory effect on the aggressive behavior of lactating female rats.

Inoculation of newly hatched broiler chicks with two Brazilian isolates of Salmonella Heidelberg strains with different virulence gene profiles, antimicrobial resistance, and pulsed field gel electrophoresis patterns to intestinal changes evaluation

Salmonella Heidelberg is one of the 3 most frequently isolated serovars from human Salmonella cases in Canada, and the fourth most commonly reported Salmonella serovar in human foodborne disease cases in the United States. Since 1962, Salmonella Heidelberg has been isolated and reported in poultry and poultry products in Brazil. The poultry industry has focused efforts on reducing salmonellae incidence in live production in an effort to reduce Salmonella in the processing plant. A better understanding of the initial infection in chicks could provide approaches to control Salmonella contamination. The objective of the present study was to evaluate 2 Salmonella Heidelberg strains that differed in the presence of virulence genes invA, agfA, and lpfA; antimicrobial resistance profiles; and epidemiologic profiles on aspects of pathogenicity and intestinal morphology. Newly hatched broiler chicks were inoculated with 2 strains (SH23 and SH35) of Salmonella Heidelberg and cecal morphometry, histopathology, electron microscopy, and bacterial counts in the liver and cecum were assessed. The SH23 and SH35 strains resulted in different changes in villi height and crypt depth and inflammatory cell infiltration in the cecum. The SH35 group had higher liver and cecum bacterial cell counts when compared with SH23 strains.

Behavior of Salmonella heidelberg and Salmonella enteritidis strains following broiler chick inoculation: evaluation of cecal morphometry, liver and cecum bacterial counts and fecal excretion patterns

Over the years, Salmonella Heidelberg (SH) has gained prominence in North America poultry production and in the poultry production of other countries. Salmonella Heidelberg has been isolated and reported from poultry and poultry products in Brazil since 1962, whereas Salmonella Enteritidis (SE) has only emerged as a serious problem in poultry and public health since 1993. These strains of Salmonella can cause intestinal problems in newly hatched chicks, and infection may persist until adulthood. Upon slaughter of chickens, Salmonella can contaminate carcasses, a condition that poses a threat to human health. The aim of this study was to compare the fecal excretion of Salmonella Enteritidis and Salmonella Heidelberg in newly hatched chicks (orally inoculated with 105ufc/mL each) until 20 days of age. In addition, the ratio of cecal villus height:crypt depth (morphometry) and liver and cecum cell counts was analyzed in chicks ranging from 0 to 3 days of age and infected with these two Salmonella strains. One hundred seventeen chicks were separated into one of three experimental groups: a control group, an SE-infected group and an SH-infected group. Eight chicks per group were euthanized at 6, 12 and 72 hours post-inoculation (pi) to allow for Salmonella isolation from the liver and cecum and for the collection of the cecum for villi and crypt analysis. Other birds were allowed to mature to 20 days of age and cloacal swabs were taken at 2, 6, 13 and 20 days pi to compare the fecal excretion of inoculated strains. The Salmonella Enteritidis group had a higher number of cells excreted during the trial. Both strains were isolated from the liver and cecum by 6h pi. At 12h pi the Salmonella Heidelberg group had high cell counts in the cecum. No difference was found in liver cell counts. Both strains showed lower villus height:crypt depth ratio than the control group post-infection.

Detection of virulence-associated genes in Salmonella Enteritidis isolates from chicken in South of Brazil

Salmonella spp. are considered the main agents of foodborne disease and Salmonella Enteritidis is one of the most frequently isolated serovars worldwide. The virulence of Salmonella spp. and their interaction with the host are complex processes involving virulence factors to overcome host defenses. The purpose of this study was to detect virulence genes in S. Enteritidis isolates from poultry in the South of Brazil. PCR-based assays were developed in order to detect nine genes (lpfA, agfA, sefA, invA, hilA, avrA, sopE, sivH and spvC) associated with the virulence in eighty-four isolates of S. Enteritidis isolated from poultry. The invA, hilA, sivH, sefA and avrA genes were present in 100% of the isolates; lpfA and sopE were present in 99%; agfA was present in 96%; and the spvC gene was present in 92%. It was possible to characterize the isolates with four different genetic profiles (P1, P2, P3 and P4), as it follows: P1, positive for all genes; P2, negative only for spvC; P3, negative for agfA; and P4, negative for lpfA, spvC and sopE. The most prevalent profile was P1, which was present in 88% of the isolates. Although all isolates belong to the same serovar, it was possible to observe variations in the presence of these virulence-associated genes between different isolates. The characterization of the mechanisms of virulence circulating in the population of Salmonella Enteritidis is important for a better understanding of its biology and pathogenicity. The frequency of these genes and the establishment of genetic profiles can be used to determine patterns of virulence. These patterns, associated with in vivo studies, may help develop tools to predict the ability of virulence of different strains.

Antimicrobial resistance in Campylobacter spp isolated from broiler flocks

The aim of this study was to assess the antimicrobial susceptibility of 62 Campylobacter spp. strains obtained from broiler flocks using the agar diffusion method. The Campylobacter spp strains were isolated from 22 flocks aged between 3 and 5 weeks of life, isolated from cloacae swabs, stools and cecal droppings in the farm and from the carcass rinsing in the slaughterhouse. Campylobacter spp strains were tested on Mueller-Hilton (MH) agar (27 samples) and MH plus TTC agar (35 samples). The antimicrobial susceptibility test revealed a 62.5% resistance to at least one drug, especially to enrofloxacin (71%), neomycin (50%), lincomycin (50%), tetracycline (43%), penicillin (42%), ceftiofur (33%) amoxicillin (27%), spiramycin (20%), ampicillin (18%) and norfloxacin (14%), whereas a lower percentage of strains was resistant to erythromycin (10%) and doxycycline (10%). All strains were sensitive to gentamicin and lincomycin-spectinomycin and 80% of them to colistin. These results indicate that it is necessary to reduce the use of antimicrobials in veterinary and human medicine.

Isolamento de Salmonella Heidelberg em diferentes pontos da tecnologia de abate de frangos de corte

Bacteria of the genus Salmonella are part of the normal flora of poultry, and its occurrence in poultry products varies with the production management methods and slaughter technology, representing risks to the consumer and difficulties in exports. S. Heidelberg appears to be more invasive and to cause more severe disease than other non-typhoidal serovars. The objective of the present study was to search for Salmonella at different points of the slaughterhouse and to report on the isolation of S. Heidelberg in a slaughterhouse under federal inspection. S. Heidelberg was isolated in poultry soon after feathering-out and in the chiller water, indicating that, although it was not isolated at another sampled points, the bacteria was present in the environment and could contaminate carcasses ready for consumption, with an impact on public health. This concern is underscored by the fact that S. Heidelberg is a proven causative agent of foodborne infections.

Número mais provável de Salmonella isoladas de carcaças de frango resfriadas

Salmonella in poultry remains an important worldwide problem, and among foodborne pathogens, the Salmonella appears as one of the most important outbreaks agents. To assess the risks of acquiring infection via undercooked poultry or cross contamination from chickens, it is important to determine the extent of the contamination on raw poultry with this pathogen. In this study, 180 refrigerated broiler carcasses, obtained from local stores, were assessed to recover Salmonella by the most probable number (MPN) method to quantify bacterias cells onto brilliant green agar with novobiocin (BGN) and xylose lysin tergitol 4 agar (XLT4). The results showed 12,2% occurrence of Salmonella by conventional microbiological method from refrigerated broiler carcasses. The MPN per ml rates was 2,7 cells on XLT4 agar and 1,3 cells on BGN agar plate. The Salmonella serovars isolated from broiler carcasses were S. Enteritidis, S. Agona, S. Rissen, S. Heidelberg and S. Livingstone. Results analysis showed that could be a variable number of cells contaminating refrigerated broiler carcasses, which have been selling to the consumer.

Avaliação in vitro de clorexidina, amônia quaternária e ácido peracético frente a amostras de Salmonella Heidelberg isoladas de abatedouro avícola em 2005 e 2009

The objective of this investigation was to evaluate the in vitro sensibility of Salmonella Heidelberg to three commercially available disinfectants used for sanitization in poultry slaughterhouses. A total of 20 S. Heidelberg were tested (14 isolated in 2005 and six in 2009), and as active ingredients were used chlorhexidine (0.5%), quaternary ammonium (0.5 %) and peracetic acid (1%) at contact intervals of 5, 10, 15 e 20 minutes. All isolates were found to be sensitive to peracetic acid at four specific contact intervals. One hundred percent of S. Heidelberg isolated in 2005 was found to be sensitive to quaternary ammonium, while 33% of 2009 isolates were resistant at a 5-minute contact interval and 16.6% at 10-minutes. With respect to chlorhexidine, 25% of the 2005 isolates were resistant at a 5-minute contact interval, 33% of the 2009 isolates were resistant with the same time, and 17% at a 10-minute contact interval. It can be concluded that the highest disinfectant activity in vitro was found to be with peracetic acid for S. Heidelberg isolates in 2005 and 2009, whereas chlorhexidine and quaternary ammonium had a reduced action against 2009 isolates, indicating the progression of bacterial resistance against these sanitizers and the need for periodic evaluation and rotation of active principles for sanitization.

In vitro efficiency of disinfectants against salmonella enteritidis samples isolated from broiler carcasses

The threat to public health represented by Salmonella is at least partially a consequence of its ecology in poultry hosts. Good manufacturing practices in the processing plant can reduce the contamination of poultry products, and critical control point principles are essential throughout the chain production. One procedure adopted in critical points control to prevent and to reduce Salmonella in farms and poultry products is the use of disinfectants. This study aimed at evaluating disinfectant efficiency against Salmonella enteritidis samples isolated from broiler carcasses in Rio Grande do Sul State between 1995 and 1996. The tested disinfectants were: phenol 1:256, quaternary ammonium 1:2500, glutaraldehyde 1:200, and iodine 1:500, with contact times of 5, 10, 15, and 20 in an in vitro test. .Phenolic compounds showed better results, iodine and glutaraldehyde showed intermediary results, and quaternary ammonium presented efficiency at all contact times evaluated in the in vitro test.

Campylobacter in broiler slaughter samples assessed by direct count on mCCDA and Campy-Cefex agar

Campylobacter spp. cause foodborne illnesses in humans primarily through the consumption of contaminated chicken. The aim of this study was to evaluate the United States Department of Agricultures (USDA) recommended methodology, protocol MLG 41.02, for the isolation, identification and direct plate counting of Campylobacter jejuni and C. coli samples from the broiler slaughtering process. A plating method using both mCCDA and Campy-Cefex agars is recommended to recover Campylobacter cells. It is also possible to use this method in different matrices (cloacal swabs and water samples). Cloacal swabs, samples from pre-chiller and post-chiller carcasses and samples of pre-chiller, chiller and direct supply water were collected each week for four weeks from the same flock at a slaughterhouse located in an abattoir in southern Brazil. Samples were analyzed to directly count Campylobacter spp., and the results showed a high frequency of Campylobacter spp. on Campy-Cefex agar. For the isolated species, 72% were identified as Campylobacter jejuni and 38% as Campylobacter coli. It was possible to count Campylobacter jejuni and Campylobacter coli from different samples, including the water supply samples, using the two-agar method. These results suggest that slaughterhouses can use direct counting methods with both agars and different matrices as a monitoring tool to assess the presence of Campylobacter bacteria in their products.