Immunocytochemistry of bone marrow aspirates: a tool in the diagnosis of feline leukemia virus infection in cats.

Feline leukemia virus (FeLV) is a highly debilitating cat pathogen due to its ability to cause many pathological changes. Therefore, identifying the virus directly in bone marrow can be a highly relevant diagnostic tool even in the absence of viraemia. The aim of this study was to compare the diagnostic efficiency of immunocytochemistry (ICC) of bone marrow aspirates with enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Blood samples were collected from 188 cats and separated into aliquots of whole blood for nested PCR using the U3 LTR region and the gag gene of FeLV-A as reference and serum for detection of the p27 antigen by ELISA. Bone marrow samples from these cats were placed on silanized slides for anti-FeLV ICC using gp70 as primary antibody. A total of 28.2% of the cats tested for FeLV were positive in at least one of the tests, with 26.6% positive by PCR, 18.1% by ICC and 11.2% by ELISA. Cohen's kappa agreement test revealed moderate agreement between ELISA and PCR results and substantial agreement between ICC and ELISA and between ICC and PCR. The results indicated that ICC of bone marrow is an efficient novel diagnostic test for FeLV infection.

PARROT BORNAVIRUSES IN PSITTACINES KEPT IN CAPTIVITY IN THE STATE OF SANTA CATARINA, BRAZIL.

Parrot bornaviruses are responsible for proventricular dilatation disease (PDD) in psittacines. This study aimed to determine the occurrence and factors associated with Parrot bornaviruses infection in psittacines kept in captivity in a state in the southern region of Brazil. A cross-sectional study was carried out with 192 birds from two facilities (A and B) in 2019, using choanal, esophageal, and cloacal swabs and feathers, totaling 768 samples subjected to reverse-transcription polymerase chain reaction (RT-PCR), for the matrix (M) protein gene with a final product of 350 base pairs (bp). Genetic sequencing of three positive samples was performed by the Sanger method. In the study, the overall virus occurrence was 35.9% (69/192), with 40.4% (42/104) in Facility A and 30.7% (27/88) in Facility B. Sequencing analysis of the samples revealed the presence of Parrot bornavirus 2 (PaBV-2) in both facilities. Swab samples from the choanal (40/69), esophageal (30/69), cloacal (35/69), and feather (15/69) tested positive, facilitating the molecular diagnosis of Parrot bornaviruses. The results indicated that there is no single ideal sample type for antemortem molecular diagnosis of this virus. Simultaneously testing all four samples at the same time point yielded more diagnoses than testing any single sample among the four. Most of the 29 sampled psittacine species were native, and 46.9% of the birds (90/192) consisted of endangered species. Among the psittacines that tested positive, 88.4% (61/69) were clinically healthy, and 8.7% (6/69) exhibited clinical or behavioral signs, including behavioral changes, alterations in feathering, and changes in body score at the time of collection. This study showcases the application of minimally invasive sampling for diagnosing Parrot bornaviruses, enabling sample collection when the birds are restrained for clinical evaluation. This approach facilitates a prompt and effective antemortem diagnosis, thereby serving as an efficient screening method for parrots kept in captivity.

Detection of virulence genes and antimicrobial susceptibility profile of Listeria monocytogenes isolates recovered from artisanal cheese produced in the Southern region of Brazil.

Listeria monocytogenes is an opportunistic pathogen that causes listeriosis, a foodborne disease with low incidence but with high mortality rate in humans. This microorganism has been recovered from several dairy products, especially those produced with raw milk. The objective of this work was to investigate the presence of virulence genes, and also to define the antimicrobial susceptibility profile of L. monocytogenes isolates recovered from serrano artisanal cheese produced in Southern region of Brazil. Nine strains of L. monocytogenes (serotypes 1/2b and 4b) were evaluated through PCR to detect the presence of the virulence genes hly, inlA, inlC, inlJ, actA, plcB and iap, while antimicrobial susceptibility profile was determined via disk diffusion method. All strains exhibited the presence of the genes hly and plcB, whereas the other genes (iap, actA, inlA, inlC and inlJ) were only detected in eight strains. We verified that all strains were resistant to at least one antimicrobial agent and three of them showed multidrug resistance. These findings demonstrated the serrano artisanal cheese offers risks to consumers' health and point to a need of adaptations and monitoring of manufacturing process of this food, in order to prevent the dissemination of L. monocytogenes.

Enterotoxigenic potential of Staphylococcus spp. isolates recovered from raw milk and artisanal cheese.

In this work, we investigated the phenotypic profile of Staphylococcus spp. isolates recovered from raw milk and artisanal cheese, and their enterotoxigenic potential through the detection of classical enterotoxin genes (sea, seb, sec, sed and see). A total of 104 isolates (58 coagulase-positive Staphylococcus - CoPS; and 46 coagulase-negative Staphylococcus- CoNS) were used, of which 33 were retrieved from raw milk and 71 from artisanal cheese produced in the Serrana region of Santa Catarina. Identification of CoPS was conducted via biochemical tests. Detection of the genes sea, seb, sec, sed, and see was carried out by multiplex PCR technique. Among the 58 CoPS analyzed, 64% were identified as S. aureus, 22% as S. scheiferi coagulans, 12% as S. hyicus and as 2% S. intermedius. In the present study was noted that 40% of CoPS isolates retrieved from milk harbored seb gene, while only one from artisanal cheese was positive for gene sea. In this study all CoNS samples investigated were negative for enterotoxins genes. The enterotoxigenic potential of CoPS, is an issue of great importance for public health. For that reason, it is necessary that cheese factories strictly follow the safety processes involved in manufacturing.