Detection of Thermoactinomyces Species in Selected Agricultural Substrates from Queensland

Abstract

Selected overheated substrates commercially available for public use in sub-tropical Queensland, Australia were screened for the presence of Thermoactinomyces species using an air sampler. All substrates with the exception of tea tree mulch were found to contain Thermoactinomyces species. Subsequent 16S rDNA oligonucleotide sequencing of the selected eight isolates indicated that some of these species were closely related to previously reported allergenic Thermoactinomyces vulgaris and Laceyella sacchari. In view of this, the isolates were tested to determine their adhesion ability and cytotoxicity to human lung cells (calu-3 cells). The results indicated that all eight isolates were highly adherent and showed cytotoxicity to this cell line. These findings might indicate that the presence of such species in overheated agricultural materials may constitute a public health risk if storage and handling conditions are not optimal and do not meet criteria defined for sub-tropical climates.

Identification of Thermophilic Aerobic Sporeformers in Bedding Material of Compost-Bedded Dairy Cows Using Microbial and Molecular Methods

“…The TAS amount in the unused bedding material from the store in winter 2017 was 1.96 log10 cfu/g, being lower than log10 cfu/g-values of the unused wood chips (<4.00-6.70 log10 cfu/g) identified by Driehuis et al [26]. Nevertheless, we also identified TAS spores in the stored bedding, as already shown [26,28]. Driehuis et al [26] postulated that TAS in stored products are due to the self-heating of the bedding material in the storage area.…”

“…The fact that the period between the complete renewal of the litter and the sampling day showed tendencies (p < 0.1; regression coefficient of −0.01 ± 0.00; Table S2) on the TAS concentration may be related to the fact that the fresh litter partly already contains TAS spores [26,28]. In the present study, we identified 1.96 log10 cfu TAS per g bedding material in one sample from the stock.…”

“…Bacillus licheniformis, Geobacillus thermodenitrificans and Ureibacillus thermosphaericus have previously been found in CBP samples [25,26]. Laceyella sacchari and Thermoactinomyces vulgaris are frequently isolated from outdoor environments such as soil and grassy pastures and thus show a wide distribution in cattle environments [28]. Consequently, the broad species spectrum is expected.…”

“…Accordingly, Wang et al [27] identified Bacillus licheniformis, Geobacillus thermodenitrificans and Ureibacillus thermophaericus in poultry and cattle manure composts. Furthermore, the TAS species Laceyella sacchari and Thermoactinomyces vulgaris, leading to respiratory diseases in farm animals, are frequently isolated from outdoor environments such as soil and grassy pastures as well as from mouldy hay, grain and horse manure [28]. Bacillus licheniformis is wildly distributed in the cattle environment and is detected, e.g., in fodders and in faeces.…”

Extrinsic allergic alveolitis-causing actinomycetes in indoor and farm environments

“…However, a pilot study, carried out in September to October 1989 around Queensland sugar mills, concluded that workers in these environments presented with symptoms related to certain occupational lung disease29 . In a more recent study Brinkmann et al30 investigated selected overheated substrates commercially available for public use in sub-tropical Queensland in Australia and detected the presence of thermoactinomycetes (Figure 1). Subsequent molecular identification of the isolates confirmed their close relationship to previously reported allergenic Thermoactinomyces vulgaris and Laceyella sacchari.…”