Poster Presentation The 2nd Prato Conference on the Pathogenesis of Bacterial Diseases of Animals 2012

Survivability of Mycoplasma hyopneumoniae on dry surfaces and dust (#53)

Christopher Browne 1 , Anette Loeffler 1 , David Lloyd 1 , Mandy Nevel 1
  1. The Royal Veterinary College, Hertfordshire, UK, AL9 7TA

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the causal agent of enzootic pneumonia (EP). Transmission of M. hyopneumoniae is via direct contact and aerosol spread (Stärk et al., 1998). Transmission via contaminated environments may also occur but little is known about the persistence and survivability of M. hyopneumoniae within the environment (Friis, 1973). The aim of this work is to investigate in vitro thesurvivability of M. hyopneumoniae on surfaces and dust under conditions representative of pig accommodation. M. hyopneumoniae (40μl) was dried out onto 6-well plates for 0,1,2,4,8 and 16 days, and then stored at three temperature ranges (4°C, 25°C and 37°C). Growth was assessed by serial dilution in 96-well plates, measuring colour changes units (CCU) per ml. The dilutions were grown in Friis medium, incubated at 37°C, and read after the growth period. The results indicate (figure 1) that dried M. hyopneumoniae was able survive up to eight days when stored at 4°C, but only two and one days at 25°C and 37°C respectively, this is in agreement with Friis, (1973) who showed that M. hyopneumoniae could not survive when dried for longer than eight days (20 - 25°C).

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Figure 1: The survivability of M. hyopneumoniae when dried at 4°C, 25°C and 37°C from 0 to 16 days.

Goodwin, (1985) explored the survival of M. hyopneumoniae on filter paper and cloth, but not on dust, a known risk factor of EP (Stärk et al., 1998). Here, M. hyopneumoniae was deposited onto autoclaved pig barn dust, allowed to dry and serial dilutions were performed. The results indicated that dust inhibited M. hyopneumoniae growth from dilutions of 10-1 and 10-2, but continued to grow at higher dilutions. Stärk et al., (1998) found that dust inhibited M. hyopneumoniae detection by nested PCR, similarly to the culture findings seen here. In conclusion, M. hyopneumoniae can survive for substantial periods on plastic (polystyrene) surfaces and on dust, even though dust may have an inhibitory effect. Investigations into novel control strategies, which address such environmental contamination, are warranted in the future.

  1. FRIIS, N. F. (1973) Resistance of porcine Mycoplasmas to drying. Acta Veterinaria Scandinavica 14, 489-491.
  2. GOODWIN, R. F. W. (1985) Apparent reinfection of enzootic-pneumonia-free pig herds - search for possible causes. Veterinary Record 116, 690-694.
  3. STARK, K. D., NICOLET, J. & FREY, J. (1998) Detection of Mycoplasma hyopneumoniae by air sampling with a nested PCR assay. Appl Environ Microbiol 64, 543-548.