title: Evaluation of survival of Actinobacillus pleuropneumoniae and Haemophilus parasuis in four liquid media and two swab specimen transport systems.
abstract: OBJECTIVE
  To determine duration and rates of recovery of Actinobacillus pleuropneumoniae and Haemophilus parasuis from 4 liquid media and 2 swab specimen transport systems and compare findings with those of Escherichia coli.
  
  
  METHODS
  One strain each of A pleuropneumoniae (biovar 1, serotype 1), H parasuis (serovar 5), and E coli (serotype O149:K91:H19).
  
  
  METHODS
  Strains were incubated in brain heart infusion broth supplemented with horse serum and other nutrients or in horse serum alone, with and without nicotinamide-adenine dinucleotide in both instances, for 150 days at 4 degrees C or room temperature (21 degrees C). Similarly, strains were tested in Stuart and Amies transport systems after storage at room temperature for 8 days.
  
  
  RESULTS
  Colony counts greater than those of the initial inoculum were observed after incubation in horse serum for A pleuropneumoniae but not for H parasuis. Overall, incubation at 4 degrees C in the 4 liquid media resulted in longer recovery duration and higher rates than at room temperature. Culture of H parasuis resulted in lower recovery rates and shorter durations of recovery than culture of A pleuropneumoniae, except for culture in horse serum. Haemophilus parasuis survived longer than A pleuropneumoniae in the transport systems, and all organisms survived longer in the Amies system.
  
  
  CONCLUSIONS
  Survival of A pleuropneumoniae and H parasuis indicated that horse serum prolongs survivability, which may result in exposure of more animals during a prolonged period. The Amies system might be a good choice for collection of clinical samples from animals, especially for recovery of H parasuis.
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000254:growth & development* / Q000302:isolation & purification; D000818:Animals; D015169:Colony Count, Microbial / Q000662:veterinary; D003470:Culture Media; D004926:Escherichia coli / Q000254:growth & development; D006190:Haemophilus / Q000254:growth & development* / Q000302:isolation & purification; D006736:Horses; D013048:Specimen Handling / Q000379:methods
chemical_list: D003470:Culture Media