title: Selective medium for culture of Mycoplasma hyopneumoniae.
abstract: The fastidious porcine respiratory pathogen Mycoplasma hyopneumoniae has proven difficult to culture since it was first isolated in 1965. A reliable solid medium has been particularly challenging. Moreover, clinical and pathological samples often contain the fast-growing M. hyorhinis which contaminates and overgrows M. hyopneumoniae in primary culture. The aim of this study was to optimise the culture medium for recovery of M. hyopneumoniae and to devise a medium for selection of M. hyopneumoniae from clinical samples also containing M. hyorhinis. The solid medium devised by Niels Friis was improved by use of Purified agar and incorporation of DEAE-dextran. Addition of glucose or neutralization of acidity in liquid medium with NaOH did not improve the final yield of viable organisms or alter the timing of peak viability. Analysis of the relative susceptibility of M. hyopneumoniae and M. hyorhinis strains to four antimicrobials showed that M. hyopneumoniae is less susceptible than M. hyorhinis to kanamycin. This was consistent in all UK and Danish strains tested. A concentration of 2μg/ml of kanamycin selectively inhibited the growth of all M. hyorhinis tested, while M. hyopneumoniae was able to grow. This forms the basis of an effective selective culture medium for M. hyopneumoniae.
authors: Department of Pathology & Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
authors: Beth S
authors: BS
authors: Cook
authors: Department of Pathology & Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
authors: Jessica G
authors: JG
authors: Beddow
authors: Department of Pathology & Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
authors: Lucía
authors: L
authors: Manso-Silván
authors: Department of Pathology & Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
authors: Gareth A
authors: GA
authors: Maglennon
authors: Department of Pathology & Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK. Electronic address: arycroft@rvc.ac.uk.
authors: Andrew N
authors: AN
authors: Rycroft
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D045705:Mycoplasma hyopneumoniae / Q000502:physiology*; D045790:Mycoplasma hyorhinis / Q000502:physiology; D013045:Species Specificity
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media
keywords: Enzootic pneumonia; Mycoplasma hyopneumoniae; Pig; Selective culture