The investigation was performed in the farm where polyarthritis was observed in cattle for the last two years. The farm consisted 106 milkings cows and 250 fattened calves per year. The calves originated partly from the farm and partly have been bought at the market. They suffered mostly from bronchitis and bronchopeumonia. Clinical symptoms of polyarthritis associated with anorexia, growth inhibition and moving discordance appeared in 28 culled fattened bulls. First symptoms of painfulness of the joints have been observed in some animals already 1—2 months after fattening started. Most disorders intensity has been stated at the end of fattening period, when the swelling and deformation in consequence of chronic tissues inflamation, mostly in carpal- and tarsal- then in elbow-, shoulder-, knee- and also hip- joints, developed. Post-mortem findings revealed fibrinous exudate in the joints and degenerative lesions on the surface of joint cartilages. In one living bull, Mycoplasma bovis was isolated from the joint exudate obtained by punction of the carpal joint. Mycoplasma was isolated also from the nasal swabs in 15 amongst 17 collected from 1—20-mont -old animals showing polyarthritis symptoms. The isolation of Mycoplasma and negative results of bacteriological examination indicate the pathogenic role of these microorganisms in enzootic polyarthritis in Poland.
Mycoplasma bovis is the smallest known bacterium that does not have a cell wall. It is therefore resistant to some antibiotics that inhibit the synthesis of the cell structure. Little is known about the mechanisms of antibiotic resistance in M. bovis, since it has no plasmids and there are insufficient data about the role of the biofilm formation by these bacteria. Previous studies have shown that the development of antibiotic resistance is due to gene mutations. Antibiotics generally considered as effective against M. bovis infection are macrolides, fluoroquinolones, tetracyclines, lincosamides, aminoglycosides, and chloramphenicol. Several recent studies, however, indicate that the efficacy of tetracyclines, macrolides, and lincosamides has diminished. Increased resistance to erythromycin, spectinomycin, and tilmicosin, antibiotics commonly used in the treatment of M. bovis infections, has also been reported. Among field strains of M. bovis no resistance or rare resistance has only been observed for enrofloxacin, florfenicol, tylosin, and tulathromycin. Considering the rapidly growing antibiotic resistance of the isolated strains of M. bovis, it is necessary to search for alternative compounds that could effectively inhibit these bacteria.
The aim of the study was to investigate the influence of Mycoplasma bovis challenge in calves on the alteration of acute- phase response (APR). The study was performed on twelve calves aged 4-8 weeks. The animals were divided into two equal groups: experimental and control. Calves in the experimental group were intratracheally challenged with pathogenic strain of Mycoplasma bovis, whereas controls received sterile physiological saline as placebo. The blood samples were collected before (1st d) and after the mycoplasma challenge (3, 5, 7 and 9th d). The following parameters were assayed in serum: acute phase proteins (APPs), i.e. haptoglobin (Hp) and amyloid A (SAA), and eicosanoids such as prostaglandin E₂ (PGE₂), prostaglandin F₂ₐ (PGF₂ₐ), leukotrien B4 (LTB₄), and tromboxan B₂ (TXB₂). In calves of experimental group, a significant increase in concentrations of Hp and SAA was observed when compared with the controls. A decrease in both APPs to the initial values, i.e. before the challenge, was noted on the 9th d of experiment. On the other hand, the inoculation of Mycoplasma bovis caused a significant increase of the examined eicosanoids, which maintained elevated during the whole study. The stimulation of synthesis of APPs and eicosanoids in response to the challenge with Mycoplasma bovis probably indicates the effective activation of APR under these conditions.
This article reviews the main molecular methods used for the diagnosis of Mycoplasma bovis infection in cattle. At present, infections with these bacteria constitute a major epidemiological and economical problem in many countries. Its control is difficult because of rising antibiotic resistance and a lack of commercially available vaccines used in specific immunoprophylaxis. M. bovis infection does not cause specific clinical signs, it is therefore important to have an effective and multidirectional diagnosis. Recently, among these are molecular techniques improving the reliability of the mycoplasmal examinations. One of the basic methods is polymerase chain reaction (PCR). Different variations of PCR are constantly enhanced to attain the highest sensitivity and specificity. There were also new methods applied based on other mechanisms. For example, there is the classic PCR modification which includes a highly discriminating identification system for PCR products based on denaturing gradient gel electrophoresis (DGGE) capable of detecting difficult to cultivate microbes (like most of the mycoplasmas) and bacteria from mixed cultures. Another advanced approach for the diagnosis of M. bovis infections is DNA microarray testing. Mycoplasma diagnosis using a few tests also gives more adequate data about the origin and specific properties of examined microorganisms.
Mycoplasma mastitis is one of the most pressing problems in herds of cows, especially in regions of increased milk production. Clinical signs in infected animals are not specific and the diagnosis of its causes should be based on laboratory testing. The classical scheme of investigation used in laboratories does not allow for their detection and should be extended to one of their methods of detection. Increased opportunities to detect mycoplasma are attained by proper storage of the milk samples.
The object of the study was to evaluate the effect of an experimental vaccine against Mycoplasma bovis infections on selected humoral immune parameters in the calves. The study was carried out on twelve calves divided into two equal groups: experimental and control. The experimental calves were subcutaneously injected with experimental vaccine composed of suspension of the M. bovis field strain of with saponin and lysozyme. The control group was administered with PBS by the same route. Blood samples for laboratory analyses were collected from all the animals directly prior to the proper experiment (zero test), then at daily intervals up to the 7th day of observation and next at weekly ones up to the 12th week after the vaccination. Serum samples were examined for total bovine immunoglobulins (Ig) and their individual classes (IgG, A i M) using suitable ELISA kits. In response to the vaccine the total serum concentration of Ig was at first lower than in the control animals up to the 56th day of observation, then it increased up to the end of the study. A distinct stimulation of the IgG synthesis was observed in the experimental animals throughout the study with the exception of the 42nd and 77th days when it was slightly decreased. On the other hand the IgA concentration was considerably lower in the experimental calves when compared to the control up to the 7th day of observation, whereas it was visibly increased at day 63rd and 70th after the vaccination. In response to the vaccination the IgM concentration had comparable values to the control throughout the study with the exception of the 4th and 56th days when they were considerably higher, whereas the IgM decrease was observed only at the 21st day after the vaccination. The experimental vaccine composed of the field strain of M. bovis with saponin and lysozyme caused significant activation of selected indices of humoral immunity in the affected animals.
The aim of this study was to detect Mycoplasma species in the respiratory tract of 110, 310 and 510 day-old groups of cattle by serological, bacteriological and histopathological investigations. Antibodies against M. bovis were found in 75% of the 110 day-old, in 50% – of the 310 day-old and in 55% – of the 510 day-old groups of cattle. Bacteriological examination of the samples from nasal cavities revealed that Mycoplasma carriers were found in 60% of the 110 day-old group of cattle, 40% of the 310 day-old and 40% of the 510 day-old group of cattle. Using the PCR method Mycoplasma was isolated from 25% of lung samples of the 510 day-old group of cattle. Mycoplasma bovis and Mycoplasma dispar were confirmed by serological investigations. Foci of bronchointerstitial pneumonia were determined by histopathological examination in 27.5% of lung samples. Mycoplasma bovis was isolated in 72.7% of bronchointerstitial pneumonia cases. Data processing with an SPSS 13.0 statistical package led to the conclusion that Mycoplasma bovis was found more frequently in the 110 day-old group of cattle (the youngest age group in this study) rather than in the 310 and 510 day-old groups of cattle (χ2 = 6.531; p = 0.038). The results obtained led to the conclusion that serological, bacteriological and histopathological examinations are important in detecting particular animal – carriers of Mycoplasma.
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