Detection of high-risk Avian Pathogenic Escherichia coli (APEC) isolated from broilers in São Paulo, Brazil

Some high-risk Avian Pathogenic Escherichia coli (APEC) clones have been associated with increased economic losses caused by avian colibacillosis. They may represent an additional food consumption concern due to the potential zoonotic role causing urinary tract infections mainly related to E. coli ST73 and ST95 lineages. This study aimed to characterize APEC isolated from slaughterhouse carcasses presenting lesions compatible with avian colibacillosis. We analyzed about 6500 broilers carcasses, and 48 showed lesions consistent with colibacillosis. Forty-four strains of E. coli were isolated, with 77.27% (n = 34/44) classified as APEC. The isolates belonged to the phylogenetic groups B2 (41.17%, n = 14/34), G (20.59%, n = 7/34), A (17.65%, n = 6/34), B1 (8.82%, n = 3/34), and E (5.88%, n = 2/34). Determining the phylogenetic group of 5.88% (n = 2/34) of the strains was impossible. Moreover, 20.59% (n = 7/34) were positive to the clonal groups ST117, 8.82% (n = 3/34) to ST95, and 8.82% (n = 3/34) were classified as belonging to serogroup O78 by PCR screening. Strains of APEC from O78 serogroup and ST117 are considered high-risk clones for poultry, and our data reinforced the need for surveillance of these pathogens in poultry farms and slaughterhouses.

Evaluation of clinical and subclinical endometritis impacts on the reproductive performance and milk production of dairy cows in Brazilian herds

Clinical endometritis (CE) and subclinical endometritis (SE) are two of the main uterine diseases in dairy cows during the puerperium period that can directly affect milk production and fertility in dairy herds. The first objective of this study was to investigate the effects of the CE and SE on the subsequent reproductive performance and milk production of dairy cows in Brazilian herds, and the second objective was to evaluate the reproductive performance and milk production of dairy cows according to the positive or negative isolation of bacteria in the uterine environment. A total of 279 lactating Holstein dairy cows (28-33 days in milk) from six commercial farms were studied. These were classified into three groups: healthy cows (without CE and SE, n = 161), cows with CE (vaginal discharge score = 3 and ≥18% PMNL, n = 83) and cows with SE (absence of signs of CE and >18% PMNL, n = 35). According to the presence of bacteria isolated from the uterine environment, the animals were classified as healthy cows (n = 161), CE cows with positive (n = 68) and negative (n = 15) bacterial isolation; and SE cows with positive (n = 21) and negative (n = 14) bacterial isolation. Cows with CE (20.5%) and SE (31.4%) had a lower (p < .05) conception rate at first AI than healthy cows (47.8%). Furthermore, both cows with CE (3.1) and SE (2.8) needed more service to become pregnant than healthy cows (1.7) and more days to be pregnant (50.3 days in CE and 43.1 days in SE than healthy group; p < .001). Cows with CE (23.8 kg) and SE (23.7 kg) produced less milk than healthy cows on the day of sampling (28.2 kg); however, milk production during 305 DIM of cows with CE and SE was not impaired when compared to healthy cows. The logistic regression showed that parity, body condition score, 305 days milk production, last calving (eutocia or dystocia), twin birth and stillbirth were not associated with the incidence of CE and SE. In addition, we highlight that cows with CE and SE, but with negative bacteria isolation, did not have reproductive performance and milk production impaired during the postpartum period. These results support that the use of antibiotics would not be beneficial in these cows, contributing to the strategic and rational use of antibiotic therapy on dairy farms.

Antimicrobial Resistance and Pathogenicity of Aliarcobacter butzleri Isolated from Poultry Meat

Aliarcobacter butzleri (A. butzleri) is an emergent zoonotic food-related pathogen that can be transmitted through the consumption of poultry meat. Data regarding the pathogenicity and resistance of A. butzleri are still scarce, and the presence of virulent MDR strains of this zoonotic pathogen in poultry meat is an issue of particular concern to public health. This study aimed to characterize the pathogenicity and antimicrobial resistance profiles of A. butzleri strains isolated from poultry meat sold at retail markets in São Paulo, Brazil. The minimum inhibitory concentrations of 27 strains were determined using the broth microdilution method. The results showed that 77.7% of the isolates were resistant to clindamycin, 62.9% to florfenicol, 59.2% to nalidixic acid, 11.1% to azithromycin, 7.4% to ciprofloxacin and telithromycin, and 3.7% to erythromycin and tetracycline, although all were susceptible to gentamicin. Moreover, 55.5% of the virulent isolates were also multidrug-resistant (MDR). Three strains were selected for pathogenicity tests in vitro and in vivo. The tested strains expressed weak/moderate biofilm production and showed a diffuse adhesion pattern (3 h) in HeLa cells and toxicity in Vero cells (24 h). Experimental inoculation in 11-week-old chicks induced a transitory inflammatory enteritis. Intestinal hemorrhage and destruction of the intestinal crypts were observed in the rabbit ileal loop test. Considering the fact that Brazil is a major exporter of poultry meat, the data from this study point to the need of improvement of the diagnostic tools, as well as of the adoption of surveillance guidelines and more specific control strategies to ensure food safety, reducing the presence of pathogenic MDR strains in broilers.

Serotyping and Antimicrobial Susceptibility Profiling of Glaesserella parasuis Isolated from Diseased Swine in Brazil

Glaesserella parasuis is one of the major pathogens in swine intensive production systems. To date, 15 serovars have been described, and the prevalence of these serotypes in different geographical regions has been identified by several methods. G. parasuis outbreaks could be controlled with vaccination if it were not for serovar diversity and limited cross-serovar protection; consequently, antibiotic therapy continues to be necessary for infection control. Here, we present the isolation, identification, serotyping, and antibiotic susceptibility profiling of G. parasuis from diseased swine in Brazil. A total of 105 G. parasuis strains, originating from nine different Brazilian states, were evaluated, and serotypes 4 and 5 were found to be the most prevalent (27.6% and 24.8% respectively). Aminoglycosides, florfenicol, tiamulin, and β-lactams were tested, and they presented lower resistant rates against G. parasuis strains. The highest resistance rates were observed against tylosin (97.1%), sulfadimethoxine (89.5%), danofloxacin (80%), trimethoprim/sulfamethoxazole (62.5%), enrofloxacin (54.3%), and clindamycin (50.5%). Multidrug resistance was detected in 89.5% of tested strains, and a total of sixty resistance profiles were identified. The cluster analysis of resistance patterns showed no correlation with the isolation year or G. parasuis serotype.

Causes of Sow Mortality and Risks to Post-Mortem Findings in a Brazilian Intensive Swine Production System

The present study was conducted to investigate the risk factors for post-mortem findings and causes of sow mortality. A post-mortem examination and microbiological investigation were conducted on 123 sows from a breeding herd with 15,000 dams. The mortality of spontaneous death in sows occurred mostly in the peripartum period (53%; p < 0.05). The spontaneous deaths were associated with heart failures, hemorrhagic and perforating gastric ulcers, and liver torsion, while in the euthanized sows, the post-mortem findings were associated with locomotor disorders. A higher body condition score (BCS ≥ 3.5) increased (p < 0.05) heart failure on the post-mortem examination. The excessive use of manual obstetric interventions increased sow deaths resulting from cervix/uterus ruptures and increased the odds of death (p < 0.05) due to metritis. Sow mortality had a multifactorial etiology. Infections were polymicrobial. The main microbial agents identified from a septic lesion in locomotor, genitourinary, and respiratory systems were Trueperella pyogenes, Escherichia coli, and Actinobacillus pleuropneumoniae, respectively. In conclusion, sow mortality involved multiple risk factors and several bacterial agents. These results indicate that better management practices can reduce sow mortality in swine production and increase sow welfare.

Dynamics of Salmonella enterica and antimicrobial resistance in the Brazilian poultry industry and global impacts on public health

Non-typhoidal Salmonella enterica is a common cause of diarrhoeal disease; in humans, consumption of contaminated poultry meat is believed to be a major source. Brazil is the world’s largest exporter of chicken meat globally, and previous studies have indicated the introduction of Salmonella serovars through imported food products from Brazil. Here we provide an in-depth genomic characterisation and evolutionary analysis to investigate the most prevalent serovars and antimicrobial resistance (AMR) in Brazilian chickens and assess the impact to public health of products contaminated with S. enterica imported into the United Kingdom from Brazil. To do so, we examine 183 Salmonella genomes from chickens in Brazil and 357 genomes from humans, domestic poultry and imported Brazilian poultry products isolated in the United Kingdom. S. enterica serovars Heidelberg and Minnesota were the most prevalent serovars in Brazil and in meat products imported from Brazil into the UK. We extended our analysis to include 1,259 publicly available Salmonella Heidelberg and Salmonella Minnesota genomes for context. The Brazil genomes form clades distinct from global isolates, with temporal analysis suggesting emergence of these Salmonella Heidelberg and Salmonella Minnesota clades in the early 2000s, around the time of the 2003 introduction of the Enteritidis vaccine in Brazilian poultry. Analysis showed genomes within the Salmonella Heidelberg and Salmonella Minnesota clades shared resistance to sulphonamides, tetracyclines and beta-lactams conferred by sul2, tetA and bla_CMY-2 genes, not widely observed in other co-circulating serovars despite similar selection pressures. The sul2 and tetA genes were concomitantly carried on IncC plasmids, whereas bla_CMY-2 was either co-located with the sul2 and tetA genes on IncC plasmids or independently on IncI1 plasmids. Long-term surveillance data collected in the UK showed no increase in the incidence of Salmonella Heidelberg or Salmonella Minnesota in human cases of clinical disease in the UK following the increase of these two serovars in Brazilian poultry. In addition, almost all of the small number of UK-derived genomes which cluster with the Brazilian poultry-derived sequences could either be attributed to human cases with a recent history of foreign travel or were from imported Brazilian food products. These findings indicate that even should Salmonella from imported Brazilian poultry products reach UK consumers, they are very unlikely to be causing disease. No evidence of the Brazilian strains of Salmonella Heidelberg or Salmonella Minnesota were observed in UK domestic chickens. These findings suggest that introduction of the Salmonella Enteritidis vaccine, in addition to increasing antimicrobial use, could have resulted in replacement of salmonellae in Brazilian poultry flocks with serovars that are more drug resistant, but less associated with disease in humans in the UK. The plasmids conferring resistance to beta-lactams, sulphonamides and tetracyclines likely conferred a competitive advantage to the Salmonella Minnesota and Salmonella Heidelberg serovars in this setting of high antimicrobial use, but the apparent lack of transfer to other serovars present in the same setting suggests barriers to horizontal gene transfer that could be exploited in intervention strategies to reduce AMR. The insights obtained reinforce the importance of One Health genomic surveillance.

Non-typhoidal Salmonella enterica is a common cause of diarrhoeal disease; in humans, consumption of contaminated poultry meat is believed to be a major source. Here we determine that S. enterica serovars Heidelberg and Minnesota were the most prevalent serovars in Brazilian poultry and in poultry products imported from Brazil into the UK. However, long-term surveillance data collected by the UK Health Security Agency showed no increase in the incidence of Salmonella Heidelberg or Salmonella Minnesota in human cases of clinical disease in the UK following the increase of these two serovars in Brazilian poultry. Salmonella Heidelberg and Salmonella Minnesota clades shared resistance to sulphonamides, tetracyclines and beta-lactams conferred by sul2, tetA and bla_CMY-2 genes, not widely observed in other co-circulating serovars despite similar selection pressures. The sul2 and tetA genes were concomitantly carried on IncC plasmids, whereas bla_CMY-2 was either co-located with the sul2 and tetA genes on IncC plasmids or independently on IncI1 plasmids. These findings suggest that introduction of the Salmonella Enteritidis vaccine, in addition to increasing antimicrobial use, could have resulted in replacement of salmonellae in Brazilian poultry flocks with serovars that are more drug resistant, but less associated with disease in humans in the UK.

Assessment of the main pathogens associated with clinical and subclinical endometritis in cows by culture and MALDI-TOF mass spectrometry identification

Clinical endometritis (CE) and subclinical endometritis (SCE) are diseases that affect dairy cows during the puerperium, causing negative effects on the animals' milk production and fertility. The objective of this study was to assess the main bacteria related to cases of CE and SCE from uterine samples of dairy cows in Brazilian herds. Selective and differential media were used for isolation of aerobic and anaerobic bacteria and further MALDI-TOF mass spectrometry (MS) identification. A total of 279 lactating dairy cows with 28 to 33 d in milk from 6 commercial farms were evaluated. Initially, cows were classified in 3 groups: cytologic healthy cows (n = 161), cows with CE (n = 83), and cows with SCE (n = 35). Healthy animals presented 97 species, followed by the CE group with 53 identified species, and SCE cows presented only 21 bacterial species. We found a significantly higher isolation rate of Trueperella pyogenes in CE (26.5%) cows compared with healthy and SCE cows. Some anaerobic species were exclusively isolated from the CE group, even though they presented lower frequency. Interestingly, 18.1% of samples from CE cows and 40% of SCE cows were negative to bacterial isolation. Despite the use of culture-dependent methods instead of molecular methods, the present study enabled the identification of a complex community of 127 different species from 48 genera, composed of aerobic and anaerobic bacterial species among the 3 different animal groups. The method of sample collection, culture, and identification by MALDI-TOF MS were essential for the success of the analyses.

Antimicrobial Resistance Profile of Staphylococcus hyicus Strains Isolated from Brazilian Swine Herds

Staphylococcus hyicus is the causative agent of porcine exudative epidermitis. This disorder affects animals in all producing countries and presents a widespread occurrence in Brazil. This study evaluated strains from a historical collection in order to detect the presence of exfoliative-toxin-encoding genes (SHETB, ExhA, ExhB, ExhC, ExhD), characterize the strains using PFGE, and determine their respective antimicrobial resistance profiles. The results obtained from the evaluation of 77 strains from 1982 to 1987 and 103 strains from 2012 reveal a significant change in resistance profiles between the two periods, especially regarding the antimicrobial classes of fluoroquinolones, amphenicols, lincosamides, and pleuromutilins. The levels of multidrug resistance observed in 2012 were significantly higher than those detected in the 1980s. It was not possible to correlate the resistance profiles and presence of genes encoding toxins with the groups obtained via PFGE. Only 10.5% of the strains were negative for exfoliative toxins, and different combinations of toxins genes were identified. The changes observed in the resistance pattern of this bacterial species over the 30-year period analyzed indicate that S. hyicus could be a useful indicator in resistance monitoring programs in swine production. In a country with animal protein production such as Brazil, the results of this study reinforce the need to establish consistent monitoring programs of antimicrobial resistance in animals, as already implemented in various countries of the world.

Dermocystidium sp. infection in farmed striped catfish Pangasianodon hypophthalmus farmed in Ceará state, Northeastern Brazil

The genus Dermocystidium infects a wide range of animals. The host infection often occurs through the ingestion of endospores. The diagnosis depends on wet mounts and histopathological analysis of the affected tissue. The aim of this study was to investigate the incidence of Dermocystidium sp. infection on the skin of farmed striped catfish (Pangasianodon hypophthalmus) from a fish farm located in Fortaleza, Ceará state, northeastern Brazil. From these observations, we determined that 100% of the analyzed animals were infected with Dermocystidium sp. The wet mount and histopathology of the fish lesions revealed spore-filled cysts between the dermis and epidermis, encapsulated by connective tissue. Owing to a lack of research on the parasite and its prevalence among different fish species in Brazil and the rest of the world, additional studies are required to understand their endemicity in fish farms of Brazil, and consequently develop better disease prevention methods and increase the overall productivity.

Antimicrobial Use in Brazilian Swine Herds: Assessment of Use and Reduction Examples

Brazil, as a major pig producer, is currently experiencing the widespread use of antimicrobials as a serious issue to be addressed. For measures to be taken in this direction, the extent of the problem must be known. The goal of this study was to evaluate the use of antimicrobials in 25 Brazilian swine herds. Antimicrobial use from birth to slaughter was correlated with biosecurity and productivity. After the first assessment (2016; M0), 13 herds implemented good practices to reduce antimicrobial use. Four years after the implementation of these measures (2020; M1), data about antimicrobial usage from these herds were collected. The results of the first assessment (M0) demonstrated a troublesome scenario: the mean value of antimicrobials used was 358.4 mg/kg of pig produced; the median of the pig’s lifetime exposure to antimicrobials was 73.7%, and the median number of drugs used was seven. A positive correlation between the antimicrobials consumed and the pig’s antimicrobial exposure time was detected. Nevertheless, these data did not correlate with biosecurity score or productivity. A significant difference was detected in M1, where a median 30% reduction in antimicrobials consumed was detected. There was also a 44.3% reduction of the pig’s lifetime exposure to antimicrobials. The median number of drugs used was reduced from seven to five. Antimicrobial use did not always reflect the sanitary condition or the real therapeutic needs, easily leading to overuse.

Use of MALDI-TOF for identification and surveillance of gram-negative bacteria in captive wild psittacines

Microbiological studies of the sanitary and health status of psittacine birds that will be reintroduced is important in evaluating whether these animals act as carriers of pathogenic agents to other animals and humans. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a faster and more accurate method to identify bacteria than conventional microbiology methods. The aim of this study was to evaluate the health status of psittacines housed in captivity, by assessment of Gram-negative bacteria from fecal microbiota through MALDI- TOF MS identification. The results indicate high frequency of Gram-negative bacteria in feces (96.5%), especially from the Enterobacteriaceae family (88.7%). The most prevalent bacteria were Escherichia coli (39.0%), Proteus vulgaris (12.2%), Klebsiella spp. (12.1%) and Raoultella ornithinolytica (8.7%). Proteus hauseri, Citrobacter spp., Morganella morgannii, Providencia rettgeri, Enterobacter spp. and Escherichia hermannii were isolated with lower frequency. . All these agents are potentially pathogenic for parrots and can cause systemic infections in other animals and humans. These findings reinforce that MALDI- TOF MS proved to be a rapid and accurate method of identification of the microorganism and evaluation of the health status of psittacines, providing relevant data to assist decision-making regarding the sanitary protocols in wildlife centers, and possible future reintroduction of wild birds.

Silent mutations in ribosomal protein genes are associated with high-risk clones of carbapenem-resistant Acinetobacter baumannii prevalent in Brazil

OBJECTIVES

To analyze the relationship of ribosomal protein mutations and clonality of high-risk clones Acinetobacter baumannii.

METHODS

Seventy-nine carbapenem-resistant A. baumannii were subjected to whole-genome sequencing (Illumina NextSeq), and codifying sequences of ribosomal proteins were extracted and screened for mutations. MALDI-TOF MS analysis (Bruker Biotyper) and Spectra data from MALDI-TOF was employed to generate a dendrogram based on principal component analysis (PCA) data. Clones were identified by Multilocus sequencing typing (MLST) based on WGS.

RESULTS

Ribosomal RNA protein sequences extracted from the genomes identified mutations that were associated with clonal complexes, but most of them were silent. PCA did not cluster the isolates according to their clonality identified by MLST.

CONCLUSIONS

By comparing the nucleotide and amino acid sequences of diversified A. baumannii, and Bruker Biotyper profiles, we showed that silent mutations in ribosomal RNA nucleotides are associated with clonal complexes, but since most of the mutations were silent, MALDI-TOF MS raw data was not a useful tool for typing the high-risk clones of this species.

Vagococcus sp. a porcine pathogen: molecular and phenotypic characterization of strains isolated from diseased pigs in Brazil

INTRODUCTION

Vagococcus spp. is known for its importance as a systemic and zoonotic bacterial pathogen even though it is not often reported in pigs. This is related to the pathogen misidentification due to the lack of usage of more discriminatory diagnostic techniques. Here we present the first report of Vagococcus lutrae in swine and the characterization of Vagococcus fluvialis and Vagococcus lutrae isolated from diseased animals.

METHODOLOGY

Between 2012 and 2017, 11 strains with morphological characteristics similar to Streptococcus spp. were isolated from pigs presenting different clinical signs. Bacterial identification was performed by matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry and confirmed by 16S rRNA sequencing and biochemical profile. Strains were further genotyped by single-enzyme amplified fragment length polymorphism (SE-AFLP). Broth microdilution was used to determine the minimal inhibitory concentration of the antimicrobials of veterinary interest.

RESULTS

Ten strains were identified as V. fluvialis and one was identified as V. lutrae. The SE-AFLP analysis enabled the species differentiation with specific clustering of all V. fluvialis separately from the V. lutrae strain. Most strains presented growth in the maximum antibiotic concentration values tested for eight of the 10 analyzed antimicrobial classes.

CONCLUSIONS

The observed resistance pattern can represent a problem for veterinary and producers in the treatment of diseases associated Vagococcus spp. in swine production. Vagococcus species may also be a risk for pig industry workers. The data described here will be of great value in further understanding the behavior of this pathogen in animal production.

Chemical composition and antibacterial activity of essential oils against pathogens often related to cattle endometritis

INTRODUCTION

Endometritis is a condition marked by inflammation of the endometrium that affects dairy cows from 21 days after parturition, causing damage to herd fertility and economic losses on farms. The use of active compounds obtained from plant sources has gained importance as disease treatment agents in farm animals due to the high resistance rates currently observed against traditional antibiotics commonly used. The study was carried out to examine the chemical composition and to investigate the antibacterial activity of rosemary, cinnamon, cloves, eucalyptus, lemon, oregano and thyme essential oils against the reference strain of Escherichia coli (ATCC 25922), Fusobacterium necrophorum (ATCC 25286), Trueperella pyogenes (ATCC 19411) and Staphylococcus aureus (ATCC 29213), considered as typical bacteria causing endometritis.

METHODOLOGY

The chemical composition of the seven essential oils were analyzed by GC-MS and their antibacterial activity was evaluated by the disc diffusion method.

RESULTS

Thirty-six components were identified in total using GC-MS analyzes. The main compounds were cinnamaldehyde (86.5% for cinnamon essential oil), eugenol (85.7% for clove essential oil), 1,8-cineol (80% for eucalyptus and 47.8% rosemary essential oils), limonene (65.5% for lemon essential oil), carvacrol (72.1% for oregano essential oil) and thymol (48.8% for thyme essential oil). The disc diffusion assay revealed that cinnamon, clove, oregano, and thyme essential oils showed the best results compared to the other three essential oils, showing the largest zone of inhibition against all bacteria evaluated.

CONCLUSIONS

These findings indicated that essential oils are a potential agent to be used as an alternative for bovine endometritis treatment.

Scuticociliatosis caused by Uronema sp. in ten different ornamental aquarium reef fish in Brazil

Scuticociliatosis, caused by an opportunistic ciliate protozoan, is responsible for significant economic losses in marine ornamental fish. This study reports the occurrence of Uronema spp., parasitizing ten species of marine reef fish at an ornamental fish wholesaler: Blue green damselfish (Chromis viridis), Vanderbilt's Chromis (Chromis vanderbilti), Pennant coralfish (Heniochus acuminatus), Threespot angelfish (Apolemichthys trimaculatus), Goldspotted angelfish (Apolemichthys xanthopunctatus), Sea goldie (Pseudanthias squamipinnis), Orchid dottyback (Pseudochromis fridmani), Threadfin butterflyfish (Chaetodon auriga), Vagabond butterflyfish (Chaetodon vagabundus), and Bluecheek butterflyfish (Chaetodon semilarvatus). Diseased fish showed disorders such as hemorrhages and ulcerative lesions on the body surface. Histopathological analysis of the muscle, liver, gut, kidney, spleen, gills, and stomach revealed hemorrhages and degeneration of muscle fiber, vacuolar degeneration of hepatocyte, inflammatory process and granuloma in the liver, atrophy of intestinal villi, inflammatory process and granuloma in the kidney, melanomacrophage centers, as well as inflammatory process in the spleen, epithelial cells hyperplasia and granuloma formation in the gills, and vacuolar degeneration and eosinophils in the stomach. Due to the severity of the disease, it is necessary to implement biosecurity measures with rapid and accurate diagnosis to minimize the risk of economic losses caused by Uronema spp.

Infectious diseases in aquarium ornamental pet fish

Aquarium ornamental pet fish constitute a major segment in the pet industry, with the United States, Europe, and Japan dominating the market. There are approximately 1,500 marine fish species and over 4,500 freshwater fish species commercialized as aquarium ornamental pet fish. Fish are the fourth most common pet present in Brazilian homes. In Brazil, aquarium ornamental pet fish can be marketed and distributed from different parts of the Brazilian territory and the world. Commercialization and circulation of living animals without the use of adequate prophylactic management procedures enables dissemination of a number of agents responsible for infectious diseases. Aquarium pet fish can also carry pathogenic agents, of bacterial, viral, fungal, or parasitic etiology, that may have a zoonotic feature endangering the persons handling the animals. This review presents the main pathogenic infectious agents of bacterial, viral, andfungal etiology that affect aquarium pet fish, as well as the prevention and control measures to ensure sanitary excellence in this segment.

Edwardsiella tarda outbreak affecting fishes and aquatic birds in Brazil

Background:Edwardsiella tarda infections are frequent causes of severe outbreaks in the fish farming industry besides representing possible zoonotic risks. However, naturally occurring outbreaks that affect various species besides fishes are seldom described.

Aim: To report an outbreak of acute mortality caused by E. tarda affecting multiple species that inhabited a natural pond in the state of São Paulo, Brazil.

Materials and methods: Three adult tilapias, three Mallard ducks and one Snow egret were necropsied and subjected to further microbiological tests. Gross and microscopic lesions were documented. The antibiotic susceptibility and phylogenetic similarities among fish and avian strains were also determined. The E. tarda species was confirmed through MALDI-TOF, partial sodB sequencing and phylogenetic analysis.

Results: Macroscopical findings between the three species included intestinal dilatation, mucosal hyperaemia and mucous to liquid contents. Common histopathology findings included acute enteritis, increased number of intraepithelial lymphocytes with bacteria adhered to the intestinal epithelium and lymphoid depletion in the spleen. E. tarda was isolated from several organs from all affected species. The phylogeny employing amplified fragment length polymorphism (AFLP) of eleven strains revealed high similarity (>90%) among the isolates regardless of the affected species or sampled organs. Ten isolates of E. tarda showed susceptibility to all tested antibiotics.

Conclusions:E. tarda was identified as the cause of death of the species examined. Further studies would be necessary to determine the virulence of these strains and the possible risks regarding public health.

Phenotypic, molecular and genomic characterization of Actinobaculum suis isolated from swine in Brazil

Urinary tract infections (UTI) are considered one of the most important diseases of sows due to its close relationship with reproductive problems such as reduced litter size, increase in the rate of return to estrous, vulvar discharge, abortion, mastitis and anestrus. Actinobaculum suis is one of the main agents involved in porcine urinary tract infection and is responsible for the most severe and fatal cases in sows. In the present report, 23 A. suis strains isolated from a sow and boars in Brazil were identified by PCR and further characterized by broth microdilution, molecular typing by pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and whole-genome sequencing. All strains were sensitive to ceftiofur, linezolid, nitrofurantoin, quinupristin-dalfopristin and vancomycin. Ciprofloxacin, daptomycin, lincomycin, erythromycin and tylosin resistance was observed in 100% of tested strains. Tetracycline and tigecycline also presented high resistance rates (87% and 30.4%, respectively). PFGE with eight different restriction enzymes and three programs did not enable strain characterization; however, all strains were typed by SE-AFLP that clustered strains according to their origin, thus proving an effective tool for A. suis genotyping. Whole-genome sequencing and comparative analysis enabled species differentiation from closely related genus. This is the first report of genomic characterization of A. suis.

Assessment of different storage conditions for Staphylococcus hyicus survival

Introduction: Collecting swabs from skin lesions for bacteriological examination is frequently performed to the diagnosis of exudative epidermitis. This method is fast and non-invasive, but it depends directly on the viability of bacteria in clinical samples, which can be influenced by storage and shipment temperatures and the time of transportation. The aim of this study was to assess the capacity of four commercial transport media and swabs with no transport medium to preserve Staphylococcus hyicus (S. hyicus) for up to 10 days at room temperature and under refrigeration. Methodology: Samples were stored in swabs with no transport medium and four transport media (Amies, Amies with charcoal, Cary Blair and Stuart) for 10 days at room temperature and under refrigeration. Swabs were plated in Tween 80 Agar and colonies counted. Results: Samples kept in transport media showed better performance (P < 0.05) under refrigeration. Storage under refrigeration in Amies medium showed better results than all other transport media and swabs (P < 0.05). Amies medium and swabs with no transport medium showed comparable results in room temperature (P > 0.05). In additional, refrigerated Amies medium and swabs with no transport medium at room temperature showed high performance for up to nine and three storage days, respectively. Conclusions: The recovery of S. hyicus in samples stored in Amies medium under refrigeration was higher when compared to other transport media. In addition, swabs with no transport medium could also be indicated when samples are stored at room temperature within three days.

Prospective study of canine leptospirosis in shelter and stray dog populations: Identification of chronic carriers and different Leptospira species infecting dogs

Dogs are highly susceptible to the leptospiral infection, notably stray and sheltered dogs. Unsanitary conditions often observed in dog shelters may predispose the introduction and spread of leptospires among sheltered populations, potentially increasing the chances for the inadvertent adoption of asymptomatically infected animals. The present work describes a longitudinal study using a multidisciplinary approach for the identification of chronically infected dogs and the characterization of potentially pathogenic strains circulating among stray and sheltered dog populations in São Paulo, Brazil. A total of 123 dogs from three populations were included. The initial evaluation consisted of blood and urine quantitative PCR testing (qPCR), the detection of specific antibodies by microscopic agglutination test (MAT), physical examination and hematological and serum biochemistry analyses. The qPCR-positive dogs were prospectively examined, and reevaluations also included culture from urine samples. Positive qPCR samples were subjected to 16S rRNA and secY gene phylogenetic analysis. The recovered strains were characterized by Multilocus Sequence Typing, polyclonal serogroup identification and virulence determination. Leptospiruria was detected in all populations studied (13/123), and phylogenetic analysis revealed that 10 dogs had L. interrogans infection. Three dogs (3/13) had L. santarosai infection. The secY phylogenetic analysis revealed that the L. santarosai sequences clustered separately from those obtained from other hosts. Ten leptospiruric dogs were reevaluated, and three dogs presented persistent leptospiruria, allowing culturing from two dogs. The strains were characterized as L. interrogans serogroup Canicola (virulent) and L. santarosai serogroup Sejroe (not virulent). Serum samples were retested by MAT using the DU92 and DU114 strains as antigens, and no increased seroreactivity was detected. Asymptomatic L. santarosai infection was observed in all populations studied, suggesting a possible role of dogs in the chain of transmission of this leptospiral species. The results suggest a genetic distinction between lineages of Brazilian L. santarosai maintained by dogs and other animal hosts. Our findings revealed that dogs could act as maintenance hosts for distinct pathogenic Leptospira, highlighting also that asymptomatically infected dogs can be inadvertently admitted and adopted in dog shelters, potentially increasing the risks of zoonotic transmission.

Septicemia due to Streptococcus dysgalactiae subspecies dysgalactiae in vampire bats (Desmodus rotundus)

Beta-hemolytic Streptococcus dysgalactiae is a well-known pathogen for a wide range of animals and humans. Two subspecies are recognized: (i) equisimilis, associated to disease in horses and humans, and (ii) dysgalactiae mainly isolated from animal illness with only a few humans’ cases. This study describes the isolation and characterization of Streptococcus dysgalactiae subsp. dysgalactiae (SDSD) from vampire bats, maintained in captivity for research proposes. Animals presented neurologic, respiratory and gastroenteric symptoms and sudden death. Beta-hemolytic Gram-positive cocci were isolated in blood agar plates and further characterized as Lancefield group C. All isolates were identified as S. dysgalactiae by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and subspecies dysgalactiae was confirmed by 16S rRNA sequencing and phylogenetic analysis. Genotyping through SE-ALFP resulted in three profiles (A1–A3) with one bat being infected by profiles A1 and A3. This is the first report of SDSD causing illness in bats and especially in Desmodus rotundus species.

Pandemic extra-intestinal pathogenic Escherichia coli (ExPEC) clonal group O6-B2-ST73 as a cause of avian colibacillosis in Brazil

Extra-intestinal pathogenic Escherichia coli (ExPEC) represent an emerging pathogen, with pandemic strains increasingly involved in cases of urinary tract infections (UTIs), bacteremia, and meningitis. In addition to affecting humans, the avian pathotype of ExPEC, avian pathogenic E. coli (APEC), causes severe economic losses to the poultry industry. Several studies have revealed overlapping characteristics between APEC and human ExPEC, leading to the hypothesis of a zoonotic potential of poultry strains. However, the description of certain important pandemic clones, such as Sequence Type 73 (ST73), has not been reported in food sources. We characterized 27 temporally matched APEC strains from diverse poultry farms in Brazil belonging to the O6 serogroup because this serogroup is frequently described as a causal factor in UTI and septicemia in humans in Brazil and worldwide. The isolates were genotypically characterized by identifying ExPEC virulence factors, phylogenetically tested by phylogrouping and multilocus sequence type (MLST) analysis, and compared to determine their similarity employing the pulsed field gel electrophoresis (PFGE) technique. The strains harbored a large number of virulence determinants that are commonly described in uropathogenic E. coli (UPEC) and sepsis associated E. coli (SEPEC) strains and, to a lesser extent in neonatal meningitis associated E. coli (NMEC), such as pap (85%), sfa (100%), usp (100%), cnf1 (22%), kpsMTII (66%), hlyA (52%), and ibeA (4%). These isolates also yielded a low prevalence of some genes that are frequently described in APEC, such as iss (37%), tsh, ompT, and hlyF (8% each), and cvi/cva (0%). All strains were classified as part of the B2 phylogroup and sequence type 73 (ST73), with a cluster of 25 strains showing a clonal profile by PFGE. These results further suggest the zoonotic potential of some APEC clonal lineages and their possible role in the epidemiology of human ExPEC, in addition to providing the first description of the O6-B2-ST73 clonal group in poultry.

Molecular survey of Cytomegalovirus shedding profile in commercial pig herds in Brazil

Introduction: Porcine cytomegalovirus (PCMV) causes rhinitis in both young and older pigs. The present study describes the detection and characterization of shedding profiles of PCMV in nine farrow-to-finish Brazilian swine herds. Methodology: Tonsil swabs from sows, nursery and grow-finish pigs of nine farrow-to-finish commercial herds (n = 756) were evaluated for the presence of PCMV by PCR. Results: The virus was detected in all herds. Positive samples were concentrated in piglets of ages varying from 40 to 60 days (nursery phase), while none of the sows were positive for PCMV detection. Conclusions: These findings corroborate the literature regarding PCMV worldwide distribution, and introduce the first report of PCMV shedding profile in Brazilian pig farms.

A survey on gram-negative bacteria in saffron finches (Sicalis flaveola) from illegal wildlife trade in Brazil

No Estado de São Paulo, Brasil, os pássaros como os canários-da-terra têm sido uma das espécies mais frequentemente resgatadas do tráfico illegal e enviadas aos centros de vida selvagem. Em situações de estresse estas aves podem ser acometidas por infecções causadas por bactérias oportunistas. Este fato é de grande importância quando é planejada da reintrodução das aves na natureza. O presente trabalho foi delineado para avaliar o estado de saúde de canários-da-terra resgatados do tráfico ilegal. Foram colhidas soabes da traqueia e da cloaca de 100 aves resgatadas durante os anos de 2012 e 2013. Os resultados obtidos revelaram alta frequência de bactérias gram-negativas nas fezes e no orofaringe dos animais, com maior frequência para os membros da família Enterobacteriaceae (97,5%). Os gêneros mais frequentes foram Escherichia coli (46,55) e Klebsiella pneumoniae (10,4%). Outros microorganismos incluindo Enterobacter cloacae, Serratia liquefaciens, Serratia spp, Klebsiella oxytoca e Citrobacter freundii também foram isolados em menor frequencia de aves assintomáticas. A presença de estirpes de Escherichia coli enteropagênicas (EPEC) e as produtoras da toxina de Shiga confirmam o risco de zoonose e a importância para saúde pública deste tipo de ave. 

High-virulence CMY-2- and CTX-M-2-producing avian pathogenic Escherichia coli strains isolated from commercial turkeys

This study reports the high-virulence phylogenetic backgrounds of CMY-2- and CTX-M-2-producing avian pathogenic Escherichia coli strains isolated from turkeys sent to slaughter and condemned by airsacculitis in Brazil. Among 300 air sac samples, seven E. coli strains produced plasmid-mediated CMY-2-type AmpC, of which three carried also the bla_CTX-M-2 Extended Spectrum Beta-Lactamase encoding gene. Interestingly, the transfer of the bla_CMY-2 gene was positive for three E. coli strains, being associated with the presence of IncI1 plasmids. The complete sequence of the representative pJB10 plasmid revealed that the bla_CMY-2 gene was within a transposon-like element in the classical genetic environment consisting of tnpA-bla_CMY-2-blc-sugE structure. This plasmid with 94-kb belonged to the sequence type (ST) 12 among IncI1 plasmids, which has been associated with the worldwide spread of bla_CMY-2 among Salmonella enterica and E. coli. Furthermore, to the best of our knowledge, this is the first complete sequence of a CMY-2-encoding plasmid derived from an Escherichia coli isolated from food-producing animals in Latin America.

Molecular and serological characterization of the first Leptospira santarosai strain isolated from a dog

Leptospirosis is a zoonotic disease of global importance caused by pathogenic Leptospira species. Dogs can become asymptomatically infected, acting like reservoir hosts for pathogenic Leptospira, notably Leptospira interrogans serovar Canicola. Identification of such individuals and characterization of leptospires involved in chronic infections may unravel the role of dogs in the epidemiology of particular leptospiral strains. The aim of the present work was to describe the first Leptospira santarosai strain isolated from a dog. The dog was kept in a public shelter in São Paulo city, Brazil, and presented asymptomatic urinary shedding detected by PCR. Prospective evaluation was performed to fully characterize its chronic carrier state. The dog did not present anti-Leptospira titles or clinical/laboratorial abnormalities during the evaluations; nevertheless long-term urinary shedding was confirmed by PCR and leptospires were recovered from two occasions. The isolated strain was molecularly characterized by partial 16S rRNA and secY gene sequencing and MLST analysis. Serogroup identification was performed using polyclonal antibodies. The strain was identified as Leptospira santarosai, serogroup Sejroe. This is the first evidence in the literature of the isolation of L. santarosai in dogs. Our findings show that dogs can persistently harbor leptospires other than L. interrogans.

Genetic diversity of Streptococcus suis serotype 2 isolated from pigs in Brazil

Streptococcus suis is an emerging zoonotic pathogen that causes septicemia, meningitis, arthritis, and pneumonia in swine and humans. The present study aimed to characterize the genetic diversity of S. suis serotype 2 isolated from pigs showing signs of illness in Brazil using pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and profiling of virulence-associated markers. A total of 110 isolates were studied, 62.7% of which were isolated from the central nervous system and 19.1% from the respiratory tract. Eight genotypes were obtained from the combination of virulence genes, with 43.6% and 5.5% frequencies for the mrp (+) /epf (+) /sly (+) and mrp (-) /epf (-) /sly (-) genotypes, respectively. The presence of isolates with epf gene variation with higher molecular weight also appears to be a characteristic of Brazilian S. suis serotype 2. The PFGE and SE-AFLP were able to type all isolates and, although they presented a slight tendency to cluster according to state and year of isolation, it was also evident the grouping of different herds in the same PFGE subtype and the existence of isolates originated from the same herd classified into distinct subtypes. No further correlation between the isolation sites and mrp/epf/sly genotypes was observed.

Virulence and resistance pattern of a novel sequence type of linezolid-resistant Enterococcus faecium identified by whole-genome sequencing

Empirical use of linezolid has been advocated in neutropenic febrile patients colonised by vancomycin-resistant enterococci (VRE) because of the risk of bloodstream infection (BSI). This study aimed to genetically describe a vancomycin-resistant Enterococcus faecium (VREfm) BSI isolate resistant to linezolid (VRLRE) in a patient previously colonised by VREfm and to determine the incidence of colonisation and infection by VREfm in a bone marrow transplant unit over a 10-year period. Data for VREfm colonisation and infection were evaluated. PCR for the vanA and vanB genes, pulsed-field gel electrophoresis (PFGE) and microdilution antimicrobial susceptibility testing (vancomycin, teicoplanin, linezolid and aminoglycosides) were performed. Three isolates, including the VRLRE, were selected for whole-genome sequencing by Ion Torrent™, with E. faecium CP006620-Aus0085 used as a reference. Eighty-seven VREfm were analysed; all were linezolid-susceptible and harboured vanA, except for one blood isolate from a febrile neutropenic patient colonised by VREfm who received linezolid for 12 days and developed a BSI by VRLRE (linezolid MIC≥8μg/mL). Linezolid resistance was associated with a G2576T mutation in the 23SrRNA gene. PFGE analysis demonstrated that the 87 isolates belonged to four major clusters; however, the VRLRE presented only 50% similarity. Three sequence types (STs) were identified: ST412 (the predominant clone, which was more virulent compared with the other isolates); ST478 (linezolid-susceptible VREfm); and a novel ST named ST987 (VRLRE). SNP analysis showed a higher similarity between linezolid-susceptible VREfm and the predominant clone compared with VRLRE. VRLRE presented a G2576T mutation and belonged to a novel ST (ST987).

Shiga toxin-producing Escherichia coli (STEC): Zoonotic risks associated with psittacine pet birds in home environments

Psittacidae are frequently bred as pets worldwide, but little is known about the zoonotic risks of these animals. The objective of this study was to investigate the presence of Shiga toxin-producing Escherichia coli (STEC) in the feces of psittacine birds housed as pets. A total of 171 fecal samples (67 cockatiels, 59 budgerigars, and 45 agapornis) were cultured. Forty-two (E. coli) strains were identified, and the presence of the eae, stx1, and stx2 genes was determined using PCR. The antimicrobial resistance profiles of the STEC strains were determined using the disk diffusion method and phylogenetic analysis according to the new Clermont phylotyping method. Using these methods, 19.4% (8/42) of the STEC strains were determined to be positive for the eae and stx2 genes. The results revealed a STEC frequency of 4.6% in the birds (8/171), with a percentage of 8.47% in budgerigars (5/59), 4.47% in cockatiels (3/67), and 0% in agapornis (0/45). None of the STEC isolates belonged to the O157 serogroup. Most of the strains were classified as sensitive to the 18 antibiotics tested. None of the strains exhibited a multiresistance profile. In the phylogenetic analysis, two strains were classified as non-typeable, three were classified as B2, two were classified as F, and one was classified as Clade I. Seven of the eight STEC strains showed a clonal profile using AFLP. E. coli strains that are stx2(+) plus eae(+) are usually associated with severe human diseases such as hemorrhagic colitis and hemolytic-uremic syndrome. The STEC-positive results indicate the zoonotic risk of breeding psittacidae in home environments.

Characterization of Leptospira interrogans serovar Pomona isolated from swine in Brazil

INTRODUCTION

Leptospira interrogans swine infection is a cause of serious economic loss and a potential human health hazard. In Brazil, the most common serovars associated with swine infections are Pomona, Icterohaemorrhagie and Tarassovi. Cross-reactions among serovars and the failure of infected animals to seroconvert may complicate the interpretation of serological tests. Molecular methods with better discriminatory powers are useful tools for swine leptospirosis characterization and diagnosis.

METHODOLOGY

This study evaluated nine L. interrogans isolates from the States of Sao Paulo and Minas Gerais during different time periods. Isolates from diseased and apparently healthy swine were characterized by microscopic agglutination tests with polyclonal antibodies and were genotyped by VNTR, PFGE and MLST techniques. Broth microdilution was used to determine the minimal inhibitory concentration of the antimicrobials of veterinary interest.

RESULTS

The strains were identified as L. interrogans serogroup Pomona serovar Pomona Genotype A, while MLST grouped all of the isolates in sequence type 37. The PFGE analysis resulted in two pulsotypes with more than 70% similarity, distinguishing serovar Pomona isolates from the serovar Kennewicki reference strain. All of the isolates presented low MIC values to penicillin, ampicillin, ceftiofur and tulathromycin. High MIC values for fluoroquinolones, tiamulin, gentamicin, tetracyclines, neomycin, tilmicosin and sulfas were also observed.

CONCLUSIONS

All molecular techniques were concordant in L. interrogans serovar Pomona identification. This serovar may have a different antibiotic susceptibility profile than previously reported for Leptospira isolates.

West Nile Virus Surveillance in the Lombardy Region, Northern Italy

In 2013, the circulation of West Nile virus (WNV) was detected in the Lombardy region and the following year a surveillance programme was activated with the aim of early identification of the viral distribution in mosquitoes and wild birds. A total of 50 959 Culex spp. mosquitoes grouped in six hundred and forty-seven pools as well as 1400 birds were screened by RT-PCR for the presence of West Nile virus leading to the identification of the viral genome in 32 mosquito pools and 13 wild birds. The surveillance was able to detect the WNV circulation on an average of 42 days (CI 95% 29.98-53.86; Student's t-distribution) before the occurrence of human West Nile disease (WND) cases in the same area. These results demonstrate the presence of WNV in the Lombardy region and confirm entomological and wild birds surveillance as an effective measure for the early identification of WNV circulation in infected areas, thus providing a useful and cost-effective tool for the public health authorities in the application of measures to prevent human infection.

Clostridium perfringens type A enteritis in blue and yellow macaw (Ara ararauna)

This study describes an outbreak of necrotic enteritis caused by Clostridium perfringens type A in captive macaws (Ara ararauna). Two psittacine birds presented a history of prostration and died 18 hr after manifestation of clinical signs. The necropsy findings and histopathologic lesions were indicative of necrotic enteritis. Microbiologic assays resulted in the growth of large gram-positive bacilli that were identified as C. perfringens. PCR was used to identify clostridium toxinotypes and confirmed the identification of isolated strains as C pefringens type A, positive to gene codifying beta 2 toxin. The infection source and predisposing factors could not be ascertained.

Antimicrobial resistance and virulence gene profiles in P. multocida strains isolated from cats

Cats are often described as carriers of Pasteurella multocida in their oral microbiota. This agent is thought to cause pneumonia, conjunctivitis, rhinitis, gingivostomatitis, abscess and osteonecrosis in cats. Human infection with P. multocida has been described in several cases affecting cat owners or after cat bites. In Brazil, the cat population is approximately 21 million animals and is increasing, but there are no studies of the presence of P. multocida in the feline population or of human cases of infection associated with cats. In this study, one hundred and ninety-one healthy cats from owners and shelters in São Paulo State, Brazil, were evaluated for the presence of P. multocida in their oral cavities. Twenty animals were positive for P. multocida , and forty-one strains were selected and characterized by means of biochemical tests and PCR. The P. multocida strains were tested for capsular type, virulence genes and resistance profile. A total of 75.6% (31/41) of isolates belonged to capsular type A, and 24.4% (10/41) of the isolates were untypeable. None of the strains harboured toxA, tbpA or pfhA genes. The frequencies of the other genes tested were variable, and the data generated were used to build a dendrogram showing the relatedness of strains, which were clustered according to origin. The most common resistance profile observed was against sulfizoxazole and trimethoprim-sulphamethoxazole.

Intercostal and forearm muscle deoxygenation during respiratory fatigue in patients with heart failure: potential role of a respiratory muscle metaboreflex

The purpose of this study was to determine the effect of respiratory muscle fatigue on intercostal and forearm muscle perfusion and oxygenation in patients with heart failure. Five clinically stable heart failure patients with respiratory muscle weakness (age, 66±12 years; left ventricle ejection fraction, 34±3%) and nine matched healthy controls underwent a respiratory muscle fatigue protocol, breathing against a fixed resistance at 60% of their maximal inspiratory pressure for as long as they could sustain the predetermined inspiratory pressure. Intercostal and forearm muscle blood volume and oxygenation were continuously monitored by near-infrared spectroscopy with transducers placed on the seventh left intercostal space and the left forearm. Data were compared by two-way ANOVA and Bonferroni correction. Respiratory fatigue occurred at 5.1±1.3 min in heart failure patients and at 9.3±1.4 min in controls (P<0.05), but perceived effort, changes in heart rate, and in systolic blood pressure were similar between groups (P>0.05). Respiratory fatigue in heart failure reduced intercostal and forearm muscle blood volume (P<0.05) along with decreased tissue oxygenation both in intercostal (heart failure, -2.6±1.6%; controls, +1.6±0.5%; P<0.05) and in forearm muscles (heart failure, -4.5±0.5%; controls, +0.5±0.8%; P<0.05). These results suggest that respiratory fatigue in patients with heart failure causes an oxygen demand/delivery mismatch in respiratory muscles, probably leading to a reflex reduction in peripheral limb muscle perfusion, featuring a respiratory metaboreflex.

A novel attractant for Mexican fruit fly,Anastrepha ludens, from fermented host fruit

Chemicals from fermented chapote fruit were identified and evaluated as attractants for hungry adult Mexican fruit flies in laboratory and greenhouse bioassays. Twenty-eight chemicals identified from an attractive gas-chromatography fraction were as attractive as a chapote volatiles extract (CV) when mixed in the same amounts found in CV. Sixteen of the chemicals were slightly attractive to flies when tested individually. A mixture containing 15 of the chemicals by design and the 16th as an impurity, in arbitrary concentrations, was at least as attractive as the original CV. In a series of experiments, the number of chemicals was reduced to three by elimination of unnecessary components. The three-component mixture retained the attractiveness of the 15-component mixture. The three chemicals were 1,8-cineole, ethyl hexanoate, and hexanol (CEH). Attractiveness of the three-chemical mixture was equal to the sum of the attractiveness of the three individual components, suggesting that each chemical binds to a different receptor type that independently elicits partial attraction behavior. Optimal ratios were 10∶1∶1 of the three chemicals, respectively. Optimal test quantities ranged between 0.4-4Μg of 1,8-cineole and 40-400 ng each of ethyl hexanoate and hexanol applied to filter paper in the laboratory bioassays. A neat 10∶1∶1 mixture of the chemicals was 1.8 times more attractive than aqueous solutions ofTorula dried yeast and borax to starved 2-day-old flies when the lures were tested in competing McPhail traps in a large greenhouse cage.

Genotypic Characterization of Yersinia enterocolitica Biotype 4/O:3 Isolates from Pigs and Slaughterhouses Using SE-AFLP, ERIC-PCR, and PFGE

Yersinia enterocolitica is a foodborne pathogen that causes illness in humans and animals. The biotype 4/O:3 has been commonly associated with yersiniosis and is characterized by the presence of chromosomal and extra-chromosomal virulence genes. Molecular typing methods have been successfully used to characterize Y. enterocolitica genetic heterogeneity and to study the epidemiology of the bacteria from different origins. In this study, 320 Y. enterocolitica biotype 4/O:3 isolates originating in pigs and slaughterhouses were characterized according to the virulence profile, and 61 isolates were typified through SE-AFLP, ERIC-PCR, and PFGE techniques. The majority of the isolates originated from pigs, and the predominant virulence profile was ail+ virF+ rfbC+ ystA+, representing 83.4% of the tested isolates. All of the Y. enterocolitica 4/O:3 isolates were positive for at least ystA gene. The SE-AFLP and ERIC-PCR patterns were highly homogeneous. The SE-AFLP was more discriminative than the ERIC-PCR and tended to cluster isolates according to the slaughterhouse. Despite the limited genetic diversity of Y. enterocolitica 4/O:3, PFGE was shown to be the most discriminative technique considering one band of difference. Fattening pigs proved to be an important reservoir of Y. enterocolitica biotype 4/O:3 carrying virulence genes.

Actinobaculum suis detection using polymerase chain reaction

Actinobaculum suis is an important agent related to urinary infection in swine females. Due to its fastidious growth characteristics, the isolation of this anaerobic bacterium is difficult, thus impairing the estimation of its prevalence. The purpose of this study was to develop and test a polymerase chain reaction (PCR) for the detection and identification of A. suis and then compare these results with traditional isolation methods. Bacterial isolation and PCR were performed on one hundred and ninety-two urine samples from sows and forty-five preputial swabs from boars. The results indicate that this PCR was specific for A. suis, presenting a detection limit between 1.0 × 10¹ CFU/mL and 1.0 × 10² CFU/mL. A. suis frequencies, as measured by PCR, were 8.9% (17/192) in sow urine samples and 82.2% (37/45) in preputial swabs. Assessed using conventional culturing techniques, none of the urine samples were positive for A. suis; however, A. suis was detected in 31.1% (14/45) of the swabs. This PCR technique was shown to be an efficient method for the detection of A. suis in urine and preputial swabs.

Colistin resistance in Escherichia coli and Salmonella enterica strains isolated from swine in Brazil

Reports about acquired resistance to colistin in different bacteria species are increasing, including E. coli of animal origin, but reports of resistance in wild S. enterica of different serotypes from swine are not found in the literature. Results obtained with one hundred and twenty-six E. coli strains from diseased swine and one hundred and twenty-four S. enterica strains from diseased and carrier swine showed a frequency of 6.3% and 21% of colistin-resistant strains, respectively. When comparing the disk diffusion test with the agar dilution test to evaluate the strains, it was confirmed that the disk diffusion test is not recommended to evaluate colistin resistance as described previously. The colistin MIC 90 and MIC 50 values obtained to E. coli were 0.25 μg/mL and 0.5 μg/mL, the MIC 90 and MIC 50 to S. enterica were 1 μg/mL and 8 μg/mL. Considering the importance of colistin in control of nosocomial human infections with Gram-negative multiresistant bacteria, and the large use of this drug in animal production, the colistin resistance prevalence in enterobacteriaceae of animal origin must be monitored more closely.

Virulence genes and antimicrobial resistance profiles of Pasteurella multocida strains isolated from rabbits in Brazil

Pasteurella multocida is responsible for a wide range of diseases in domestic animals. In rabbits, the agent is related to nasal discharge, pneumonia, otitis media, pyometra, orchitis, abscess, and septicemia. One hundred and forty rabbits with respiratory diseases from four rabbitries in São Paulo State, Brazil were evaluated for the detection of P. multocida in their nasal cavities. A total of twenty-nine animals were positive to P. multocida isolation, and 46 strains were selected and characterized by means of biochemical tests and PCR. P. multocida strains were tested for capsular type, virulence genes, and resistance profile. A total of 45.6% (21/46) of isolates belonged to capsular type A, and 54.34% (25/46) of the isolates were untypeable. None of the strains harboured toxA or pfhA genes. The frequency of the other twenty genes tested was variable, and the data generated was used to build a dendrogram, showing the relatedness of strains, which were clustered according to origin. Resistance revealed to be more common against sulfonamides and cotrimoxazole, followed by erythromycin, penicillin, and amoxicillin.

Prevalence of avian pathogenic Escherichia coli (APEC) clone harboring sfa gene in Brazil

Escherichia coli sfa+ strains isolated from poultry were serotyped and characterized by polymerase chain reaction (PCR) and amplified fragment length polymorphism (AFLP). Isolates collected from 12 Brazilian poultry farms mostly belonged to serogroup O6, followed by serogroups O2, O8, O21, O46, O78, O88, O106, O111, and O143. Virulence genes associated were: iuc 90%, fim 86% neuS 60%, hly 34%, tsh 28%, crl/csg 26%, iss 26%, pap 18%, and 14% cnf. Strains from the same farm presented more than one genotypic pattern belonging to different profiles in AFLP. AFLP showed a clonal relation between Escherichia coli sfa+ serogroup O6. The virulence genes found in these strains reveal some similarity with extraintestinal E. coli (ExPEC), thus alerting for potential zoonotic risk.