Márcia Raquel Pegoraro de Macedo

Identification of Staphylococcus aureus, S. intermedius and S. hyicus by PCR amplification of coa and nuc genes

Sixty-five strains of coagulase positive staphylococci (Staphylococcus aureus, S. intermedius and S. hyicus) were identified at species level by PCR amplification of the coa gene, specific for S. aureus, and of the nuc gene, specific for S. intermedius and for S. hyicus.

Listeria spp. no processamento de lingüiça frescal em frigoríficos de Pelotas, RS, Brasil

Food that is highly manipulated, such as fresh sausages, is frequently responsible for spreading food borne diseases. Due to the threat that the bacterium Listeria monocytogenes represents to public health, the aim of this work was to study the presence of Listeria spp., especially Listeria monocytogenes, during processing of fresh sausages, in three slaughterhouses with state food inspection, in the city of Pelotas, Brazil. The raw material used for the sausage elaboration, the equipment used in the processing and the end products were analyzed. The results showed Listeria spp. in 100% of the 41 samples analyzed. Among the different species, L. innocua was the most frequent, isolated from 97.6% of the samples, followed by the L. monocytogenes and L. welshimeri that were isolated from 29.3% and 24.4% of the samples, respectively. The presence of these microorganisms in the samples analyzed, especially in the end product, shows the need for adequateness of the cleaning and sanitation practices of the food processing plants analyzed. It also shows a potential risk of listeriosis to the consumer.

Morphological, molecular and phylogenetic analyses of Diplotriaena bargusinica Skrjabin, 1917 (Nematoda: Diplotriaenidae)

The nematode Diplotriaena bargusinica is a bird air sac parasite, and its taxonomy is based mainly on morphological and morphometric characteristics. Increasing knowledge of genetic information variability has spurred the use of DNA markers in conjunction with morphological data for inferring phylogenetic relationships in different taxa. Considering the potential of molecular biology in taxonomy, this study presents the morphological and molecular characterization of D. bargusinica, and establishes the phylogenetic position of the nematode in Spirurina. Twenty partial sequences of the 18S region of D. bargusinica rDNA were generated. Phylogenetic trees were obtained through the Maximum Likelihood and Bayesian Inference methods where both had similar topology. The group Diplotriaenoidea is monophyletic and the topologies generated corroborate the phylogenetic studies based on traditional and previously performed molecular taxonomy. This study is the first to generate molecular data associated with the morphology of the species.

Occurrence of Chandleronema longigutturata (Nematoda: Acuariidae) in Procyon cancrivorus in the Neotropical region

Procyon cancrivorus is a wild animal that is found from Central America to Uruguay and northeastern Argentina. It is one of the least studied carnivore species in Brazil. For the purpose of identifying helminths that parasitize P. cancrivorus, individuals of this species that had been run over and killed by motor vehicles were collected from highways in the southern part of the state of Rio Grande do Sul. At necropsy, their organs, along with organ contents and mucous membranes, were examined for parasite collection. The nematodes found in the stomachs of these Procyonidae were cleared with lactophenol and Chandleronema longigutturata was identified. This report provides the first record of occurrences of C. longigutturata in the Neotropical region and its parasitism in P. cancrivorus.

Detection of Toxocara canis DNA in tissues of experimentally infected mice

The main etiological agent of toxocariasis is the helminth Toxocara canis. Several difficulties are found in the diagnosis of this disease, because of nonspecific clinical signs and possible cross-reactions that may occur in the available test, the indirect ELISA. Therefore, molecular diagnosis has been indicated as an alternative to conventional diagnosis. The purpose of this study was to evaluate the polymerase chain reaction (PCR) technique for the identification of T. canis in tissues of experimentally infected mice. To this end, nine mice were inoculated with 1500 embryonated eggs and were divided into two groups, the first euthanized 48 h (G1) and the other 30 days post inoculation (G2). Lungs, brain, liver and blood were collected from all the animals for DNA Extraction and tissue digestion, also was collected blood samples for DNA extraction and ELISA test (serum). Toxocara canis DNA was identified in all the inoculated animals using the ITS-2 target gene. The PCR test successfully identified the parasite in the brain, lung and liver of the animals euthanized 48 h PI and 30 days PI. This technique yielded good results in the identification of the parasite in the brain, being more sensitive than the method for the recovery of larvae, in the group with acute infection (48 h PI). The infection was confirmed by PCR within 48 h after infection, while the ELISA indicated serological conversion occurred only 14 days after inoculation. This study demonstrates the ability of PCR to identify T. canis in the liver, lungs and brain during acute and chronic infection.