Maria da Graça Fichel do Nascimento

Detection of Mycoplasma pulmonis in laboratory rats

This work was conducted on rats in two premises located in Niteroi and Rio de Janeiro, Brazil. One is classified as conventional controlled and the other, conventional. The objective of the present study was to detect the presence of Mycoplasma pulmonis in animals with symptoms of respiratory disease and low reproductive performance. In the conventional controlled premises, 16 rats of Wistar-Furth strain were necropsied while in the conventional premises necropsy was performed on 12 rats of Hooded Lister strain. The clinical samples of lungs, trachea, oropharynx, middle ear, uterus and ovaries were subjected to culturing while the sera were tested for antibody detection. From 28 rats, 57.14% (16/28) were culture positive for M. pulmonis, being 81.25% (13/16) from the conventional controlled premises, and 25.00% (3/12) from the conventional premises. The ELISA test was carried out in 20 animals of both colonies. In the conventional controlled premises, 92.86% (13/14) were positive for M. pulmonis, and 7.14% (1/14) were suspicious, while in the conventional premises, 100% (6/6) of the samples were positive. The results confirmed that M. pulmonis was the etiologic agent of the disease that affected the rats under study, and that the ELISA positivity rated higher than culture.

An Improved Method for the Recovery of Mycoplasmas from the External Ear Canal of Goats

The efficacy of ear canal flushing and ear canal and mouth swabbing methods for the isolation of mycoplasmas was investigated in 39 goats. Of the 19 goats positive for Mycoplasma spp., 14 (73.7%) were positive with the ear canal flushing method, 4 (21.0%) were positive with both ear canal flushing and mouth swabbing methods, and 1(5.3%) was positive by the mouth swabbing method. Mycoplasma arginini, M. mycoides subsp. mycoides, and M. mycoides subsp. capri were identified by direct immunofluorescence and growth inhibition tests. Previous reports on the isolation of M. arginini from the ear canal of goats were not found in the literature.

Mycoplasma synoviae infection on Newcastle disease vaccination of chickens

A doenca de Newcastle e caracterizada por manifestacoes respiratorias associadas a sintomas nervosos e/ou digestivos. Sua prevencao e feita pela vacinacao com vacinas vivas atenuadas (cepas lentogenicas) e/ou inativadas. As cepas lentogenicas podem determinar acentuada reacao pos-vacinal, principalmente na presenca de outros patogenos. Entre eles, o Mycoplasma synoviae tem importância mundial, principalmente no Brasil. A disseminacao deste agente nos planteis avicolas tem sido facilitada, devido a dificuldades de reproducao e diagnostico da doenca em aves, variacao de virulencia entre as diferentes cepas de M.synoviae e atribuicao a outros patogenos de manifestacao tipica da micoplasmose por M.synoviae. Este estudo experimental em aves (Gallus gallus) SPF, previamente infectadas por M.synoviae e depois vacinadas contra Newcastle, foi realizado com objetivo de avaliar a patogenicidade do M.synoviae pela obtencao dareacao respiratoria pos-vacinal e a resposta sorologica para o virus vacinal da doenca de Newcastle, na ausencia de fatores ambientais. Um total de 86 aves, com tres dias de idade foram utilizadas, sendo 57 infectadas via ocular e intranasal, com cepa MS WVU 1853, ativada em galinhas. Sete dias depois, 21 aves infectadas por micoplasma e 29 nao infectadas foram vacinadas contra a doenca de Newcastle. Como resultados, aves nao infectadas e vacinadas produziram resposta sorologica para o virus vacinal da doenca de Newcastle, significativamente mais elevada e mais duradora que aquelas infectadas e vacinadas. Igualmente, aves infectadas e vacinadas produziram reacoes sorologicas para M.synoviae mais baixa, que aquelas apenas infectadas. Nao foram observadas reacoes respiratorias pos-vacinal nas aves vacinadas.

In vitro activity of naturally occurring peptides (defensins) against Listeria monocytogenes

Autoclaved distilled water samples were inoculated with L. monocytogenes strain V7 and strain VPH-1, and incubated aerobically, at 30 C for 48 hours. Each strain was tested individually, and growth curves were determined at 1, 2, 3, 4, 5, 21, 24, and 48 hours. The growth or survival of L. monocytogenes was similar for both strains, with survivors at 24 hour-incubation. The microbicidal activity of one synthetic cationic peptide (NP-2) was examined against L. monocytogenes strain V7, in a water system. Antibacterial activity of NP-2 (1, 5, and 10 g/ml) was best expressed at 60 minute-incubation, with 10 g/ml of peptide, at 30 C.