Detection of Mycoplasma hyopneumoniae in bronchoalveolar lavage fluids of pigs by PCR.

In the present investigation we developed a method for the detection of Mycoplasma hyopneumoniae in bronchoalveolar lavage fluid (BALF) of pigs by PCR with a primer pair flanking a DNA fragment of 853 bp specific for M. hyopneumoniae. Several methods were tested to eliminate the amplification inhibitors present in BALFs. The best results were obtained by the extraction of the DNA from the BALFs. By the PCR performed with the extracted DNA, 10(2) CFU of M. hyopneumoniae could be detected in 1 ml of BALF from specific-pathogen-free swine experimentally inoculated with M. hyopneumoniae. DNA from 11 other mycoplasma species and 17 cell-walled bacterial species colonizing the respiratory tracts of pigs was not amplified. In a field study BALFs from 40 pigs from farms with a history of chronic pneumonia were tested for M. hyopneumoniae by cultivation and by PCR (i) with BALFs incubated in Friis medium and (ii) with DNA extracted from the BALFs. In addition, PCR was performed with postmortem lung washings from 19 of the 40 pigs, and immunofluorescence tests were carried out with sections of lungs from 18 of the 40 pigs. M. hyopneumoniae could not be detected in 18 of the 40 pigs by any of the five methods tested. The remaining 22 pigs showed a positive reaction by the PCR with DNA extracted from the BALFs and variable positive reactions by the other tests. A complete correspondence could be observed between the immunofluorescence test result and the result of PCR with DNA. The investigation shows that the PCR with DNA extracted from BALFs is a suitable technique for the sensitive and specific in vivo detection of M. hyopneumoniae.

[Bronchoalveolar lavage on pig breeding farms]. / Lungenspülungen bei Schweinen im Erzeugerbetrieb.

In 182 pigs lung lavage was performed using a endotracheal tube and a catheter. The collected bronchoalveolar lavage fluid (BALF) was examined microbiologically. With decreasing numbers alpha-hämolytic Streptococci, Bordetella bronchiseptica, Haemophilus parasuis, Pasteurella multocida were cultured. Actinobacillus pleuropneumoniae was isolated from 3 BALFs. In one farm piglets were lavaged routinely for monitoring of the lung health status.

[Demonstration of pneumonia in swine as a constant problem: culture and immunofluorescence microscopic studies of bronchioalveolar lavage (BAL) and serological findings]. / Nachweis von Pneumonieerregern bei Schweinen aus Problembeständen: Kulturelle und immunfluoreszenzmikroskopische Untersuchungen der bronchoalveolären Lavage (BAL) und serologische Befunde.

Bronchoalveolar lavage was performed in 128 pigs from five fattening units showing acute pneumonia (48 animals), subclinical purulent pneumonia (17 animals), and chronic purulent pneumonia (63 animals). These samples were investigated for bacteria. Additionally immunofluorescence microscopy as well as serological investigations were performed to detect antibodies against several bacteria and viruses. Pasteurella multocida could be detected in more than a half of the samples of pigs with acute pneumonia. Bordetella bronchiseptica and mycoplasmas were isolated in a lower amount. Probably these bacteria infected the pigs of at least one herd after a primary infection with influenza virus because (i) influenza virus could be detected in three of four animals investigated for influenza virus by culture methods, (ii) the virus could be detected in one third of the animals investigated for by immunofluorescence microscopy, and (iii) antibodies against influenza virus could be detected in almost all animals. From pigs with subclinical purulent pneumonia Bordetella bronchiseptica as the only bacterial lung pathogen could be isolated exclusively from nearly each sample. From the samples of pig suffering from chronic purulent pneumonia first of all Bordetella bronchiseptica, Pasteurella multocida and different mycoplasma species could be detected. Using cultural methods Actinobacillus pleuropneumoniae could be isolated from six samples only, in contrast to frequent positive reactions against Actinobacillus pleuropneumoniae antigens obtained by immunofluorescence microscopy and CFT.

[Treatment of swine with chronic pneumonia with chlortetracycline-medicated feed]. / Behandlungsergebnisse mit der Chlortetracyclin-Futtermedikation bei chronisch Pneumonie-kranken Schweinen.

26 fattening pigs with spontaneous severe chronic bronchopneumonitis were orally treated with feed containing 800 ppm chlortetracycline (CTC) over 3 weeks. With the help of clinical investigation, transcutaneous measurement of the oxygen-saturation of the blood, X-ray of the thorax and bronchoalveolar lavage significant effects could be measured during and after finishing the treatment. In 19 spontaneous fallen ill untreated control animals recovery could not be detected by the used methods. After the end of the 3 weeks interval there were significant differences between treated and untreated animals detectable. By this investigations practical observations that oral treatment with 800 ppm in fattening pigs is effective was verified. But because of pharmacokinetic data higher concentrations would be recommendable. In the treated pigs a significant increase of the oxygen saturation of the blood occurred not before the 8th day of treatment. This underlines the importance of sufficient length of the treatment interval.