Margareth Élide Genovez

A multiplex PCR for the detection of Brucella spp. and Leptospira spp. DNA from aborted bovine fetuses.

Bovine brucellosis and leptospirosis are important causes of bovine abortion around the world. Both diseases can be serologically diagnosed, but many factors may cause false positive and negative results. Direct methods based on bacteriological isolation are usually employed, but they are difficult, time consuming and dangerous. Monoplex polymerase chain reaction (PCR) have been successfully described for the detection of Brucella spp. and Leptospira spp. Aiming at improvement in the direct diagnosis, a multiplex PCR (mPCR) for the detection of these agents in aborted bovine fetuses is described. The detection threshold of the mPCR was evaluated in experimentally contaminated bovine clinical samples using a conventional proteinase K/SDS or a boiling-based extraction protocols. The mPCR was applied to two groups of clinical samples: 63 episodes of bovine abortion and eight hamsters experimentally infected with Leptospira interrogans serovar pomona. Adopting microbiological isolation as reference, the test showed a sensitivity of 100% in both groups of clinical samples. Seven samples collected from bovine fetuses were Brucella spp. culture negative but showed positive results in mPCR. Regarding Leptospira spp. detection, similar results were observed in three bovine clinical samples. All hamsters infected with Leptospira were positive in both microbiological culture and mPCR. The boiling extraction protocol showed better results in some clinical samples, probably by the removal of PCR inhibitors by heat treatment. The high sensitivity, simplicity and the possibility of detection of both bacteria in a single tube reaction support the use of the mPCR described in the routine diagnosis.

Ureaplasma diversum and reproductive disorder in Brazilian cows and heifers; first report.

The species Ureaplasma diversum is associated with bovine reproductive illnesses, in particular granular lesions of the vulva and vagina or granular vulvovaginitis (GVV). In Brazil, this pathology is unknown and, until this point in time, the presence of U. diversum in the Brazilian herds has been ignored. With the intention of detecting the microorganism, vulvovaginal mucuses of 152 animals located on seven farms in the São Paulo State, Brazil were analyzed. Those animals had evidence of reproductive disorders at the time of the sample collection. The technique used for microorganism detection was bacterial isolation. Statistical analysis assessed: the exposure of studied farms to U. diversum, relative risks for different symptoms, susceptibility of the animals according to age and breed. The frequency of that microorganism in tested animals was 38.8% and this frequency suggests that U. diversum can be related to GVV in Brazilian herds and possibly with other reproductive illnesses. As a result, the U. diversum differential diagnosis could be very important.

Detection of Leptospira spp. in the semen and urine of bulls serologically reactive to Leptospira interrogans serovar hardjo

This study evaluated PCR for the detection of leptospires in semen and urine of ten serologically reactive bulls, comparing these results with those obtained with other diagnosis techniques. Two collections of materials were done in alternate days. Semen and urine samples were separated in aliquots for: direct visualization in dark field microscopy; inoculation in hamsters (for semen only); isolation in culture media; and PCR. No hamster was positive by the microscopic agglutination test (MAT); kidney and liver fragments from the hamsters were used in an isolation attempt in culture media, with one positive isolation from the kidney of a hamster inoculated with semen of one bull, and from liver of hamsters inoculated with semen of three bulls. Isolation in culture was negative for all semen samples, but positive for five urine samples by direct inoculation. In PCR there was no positive result for semen samples, and only one urine sample was positive, which was coincident with one of the positive cultures. It was not possible to visualize leptospires in any of the samples by dark field microscopy.

Detection of CDT toxin genes in Campylobacter spp. strains isolated from broiler carcasses and vegetables in Sao Paulo, Brazil

Campylobacteriosis is a worldwide distributed zoonosis. One of the main virulence factors related to Campylobacter spp. in animals and humans is the cytolethal distending toxin (CDT), encoded by three adjacent genes (cdtA, cdtB, cdtC). The occurrence of Campylobacter spp. in samples of vegetables has not been reported in Brazil yet, and has seldom been described in the international literature. The detection of CDT in these strains has not been reported, either. The objectives of the present study were to determine the occurrence of Campylobacter spp. strains carrying virulence factors in samples of poultry and vegetables (lettuce and spinach) from different points of sale, thus verifying if vegetables are as an important vehicle for potentially virulent Campylobacter spp. strains as poultry. Twenty four strains were identified as Campylobacter jejuni by phenotypic and genotypic methods: 22 from broiler carcasses and two from lettuce samples. Three strains were identified as Campylobacter coli: two from broiler carcasses and one from lettuce. The presence of the cdt genes were detected in 20/24 (83.3%) C. jejuni strains, and 3/3 (100%) C. coli strains. The isolation of Campylobacter spp. strains with the cdt gene cluster in lettuce samples points to a new possible source of contamination, which could have an impact in the vegetable production chain and risk to public health. Results show that potentially virulent C. jejuni and C. coli strains remain viable in samples of broiler carcasses and vegetables at the points of sale.

Molecular subtyping of Campylobacter jejuni subsp. jejuni strains isolated from different animal species in the state of São Paulo, Brazil

O objetivo do presente trabalho foi caracterizar geneticamente estirpes de Campylobacter jejuni subsp. jejuni isoladas de humanos e de diferentes origens animais (bovinas, suinas, caes, primatas, javalis, suinos e aves de corte). Um total de 828 amostras (fezes, carcacas, fetos abortados e utero histerectomizado) foram analisadas por metodos de rotina bacteriologica e 36 estirpes de C. jejuni foram isoladas. Trinta estirpes de origem fecal humana foram obtidas de laboratorios de analises clinicas da cidade de Sao Paulo. As 66 estirpes de C. jejuni isoladas foram submetidas a caracterizacao genetica. Oligonucleotideos baseados no gene fla A foram usados na reacao de polimerase em cadeia (PCR) e amplificou um fragmento de 702 pb. Os produtos obtidos pela PCR foram avaliados pelas tecnicas de sequenciamento e analise genealogica. Analise da variabilidade genetica das 66 estirpes revelou 44 diferentes subtipos de C. jejuni. Um subtipo de origem humana apresentou sequencia identica a de C. jejuni depositada no GenBank (GENBANK acesso numero AF050186). A subtipagem das estirpes de C. jejuni baseadas no sequenciamento da regiao variavel do gene fla A e na analise do alinhamento das sequencias pelo metodo da Maxima Parcimonia, mostraram-se altamente discriminatorios fornecendo melhores condicoes para a correta diferenciacao entre estirpes originarias de surto e as isoladas esporadicamente. Este foi o primeiro estudo de subtipagem molecular de estirpes de C. jejuni de origem humana e animal utilizando a tecnica do sequenciamento com analise genealogica realizado no Estado de Sao Paulo, Brasil.

Detecção dos genes da toxina citoletal distensiva em estirpes de Campylobacter jejuni isoladas de carcaças de frangos

Eighty samples of refrigerated broiler thighs purchased in street markets and supermarkets in the city of Sao Paulo, SP, were analyzed. Thirteen Campylobacter spp. strains were isolated in 10 (12.5%) thighs, five of them from street market samples and other five from supermarkets. Eleven strains were identified as Campylobacter jejuni and two of them as Campylobacter coli. The 11 strains were confirmed to be C. jejuni using PCR for hippuricase (hip) gene. From these, multiplex-PCR showed that four (36.4%) strains presented the three genes (cdtA, cdtB, and cdtC) encoding cytolethal distending toxin: three strains from supermarket and one from street market samples. These results are important, because they demonstrate the presence of virulent C. jejuni strains in refrigerated broiler thigh samples, not only in the slaughterhouse but in the final point of the distribution chain, at the two most important food retail commercer.

An in vitro growth inhibition test for measuring the potency of Leptospira spp. Sejroe group vaccine in buffaloes

Leptospira spp. serovars Hardjo and Wollfi from Sejroe serogroup have been detected in livestock in Brazil, where the main control procedures rely on vaccination. The potency of two commercial vaccines available in this country was monitored by microagglutination test-MAT and in vitro growth inhibition test-GIT in serum samples from 33 female buffaloes divided into: G1-unvaccinated control; G2-vaccinated with Leptobac-6 containing serovars Hardjo and Wolffi and G3-vaccinated with Triangle-9 containing serovar Hardjo. G2 and G3 animals were vaccinated on day zero, and received a booster and two revaccinations on days 30, 210 and 390 and G1 animals received phosphate buffered saline. Serum samples were collected at 15-day intervals between days 0 and 60; and at 30-day intervals between days 60 and 540 and were tested by MAT and GIT with serovars Hardjo and Wolffi. G1 remained negative throughout the experiment. Both vaccines were able to induce agglutinating and growth inhibition antibodies. Six months after the last revaccination, all animals tested negative by MAT, but still were positive by GIT until the end of experimental period. GIT could be a good tool to evaluate the potency and to monitor antibodies responses of vaccines of Sejroe group serovars.

Detecção de ácidos nucléicos de Brucella spp., Leptospira spp., herpesvirus bovino e vírus da diarréia viral bovina, em fetos bovinos abortados e em animais mortos no perinatal

Samples of 114 bovine fetuses and 10 calves, which dead in perinatal period, were examined for detection of DNA. The most common detected agent was Brucella spp. in 17 samples (13.7%) followed by Leptospira spp. in 4 cases (3.2%),bovine herpesvirus (BHV) and bovine viral diarrhea (BVDV) in 3 animals (2.4%) each, and 1 for the association of BVDV and BHV. In 77.4 % (96/124) of the samples it was not possible to detect any agent.

Excretion of Brucella abortus vaccine B19 strain during a reproductive cycle in dairy cows

This paper aimed to determine the excretion period of B19 vaccine strain during a complete reproductive cycle (from estrus synchronization, artificial insemination, pregnancy and until 30 days after parturition) of dairy cows from 3 to 9 years old that were previously vaccinated from 3 to 8 months. Three groups were monitored with monthly milk and urine collection during 12 months: G1 with seven cows from 3 to 4 years old; G2 with three cows from 5 to 6 years old; and G3 with four cows from 7 to 9 years old. Urine and milk samples were submitted to bacteriological culture and urine and PCR reactions for detection of Brucella spp. and PCR-multiplex for B19 strain identification. Ring test (RT) was also performed in the milk samples, and serum samples were tested by buffered acidified plate antigen test (BAPA). All animals were serologically negative at BAPA and Brucella spp. was not isolated from both urine and milk samples. RT revealed 13/210 (6.2%) positive milk samples. PCR reactions detected DNA of Brucella spp. in 86/420 (20.5%) samples. In urine it was found a significantly higher frequency (35.2%; 74/210) than in milk (5.7%; 12/210), more frequently from the estrus to 150 days of pregnancy and after parturition (6.7%; 10/150), and from 150 days of pregnancy to parturition (3.4%; 2/60), and they were all identified as B19 strain. In three groups, intermittent excretion of B19 strain was detected mainly in urine samples, which confirmed its multiplication and persistence in cows for until 9 years.

Interference of vaccinal antibodies on serological diagnosis of leptospirosis in vaccinated buffalo using two types of commercial vaccines

The vaccinal antibodies interference represents one of the Microscopic Agglutination test - MAT limitation in the animal leptospirosis serum diagnosis. Prospective studies showing the dimensions of this effect are rare in buffaloes. This study aimed to determine the anti-Leptospira serum agglutinin profile in vaccinated female buffaloes using two types of commercial vaccines against leptospirosis: bacterin (whole bacterial cell) and purified outer membrane and to evaluate the vaccinal interference on serum diagnosis. Three groups of 11 adult buffalo females were established: G1-control, non-vaccinated, G2- vaccinated with bacterin vaccine with six serovars, G3- outer membrane purified vaccine with five serovars. A booster dose was administrated 30 days after the first vaccination (dpv) and two re-vaccinations six months a part (210 and 390 dpv). Serum samples were collected on days 0, 15, 40, 45, 60 and every 30 days until 540 dpv. G1, G2 and G3 serum samples were submitted to MAT with the serovars present in the vaccines. G1 remained always negative. Both vaccines induced serologic responses in MAT at 150 dpv against all serovars and they revealed maximum titers around 45 and 60dpv as follows: Pomona: G2 (1600) and G3 (3200); Hardjo: G2 and G3 (1600); Wolffi: G2 (800) and G3 (1600); Icterohaemorrhagiae: G2 and G3 (800); Grippotyphosa: G2 and G3 (200) and Canicola: G2 (NR) and G3 (400). Even though, the Wolffi serovar is not present in the purified outer membrane vaccine, G3 showed a response to that serovar, probably due to cross reaction to the serovar Hardjo. The G3 titers were higher and appeared earlier than in G2, but with similar serologic profiles. At the re-vaccination there was an increase on agglutinin levels, but of less intensity than those previously observed. After six months from the second revaccination (540 dfv), G2 and G3 were almost negative, which demonstrated the short diagnostic interference.