The concentration and the species composition of airborne gram-negative bacteria were studied in four cattle houses, one pig house and one poultry barn. On average only between 0.02 and 5.2% of the total number of culturable aerobic bacteria were identified as gram-negative bacteria. Obligate anaerobic gram-negative bacteria were not isolated at all. In the airborne gram-negative bacterial flora the following bacterial families dominated: the Enterobacteriaceae, the Pseudomonadaceae and the Neisseriaceae. Within the family of the Enterobacteriaceae the species Escherichia coli and Enterobacter agglomerans were predominant. In animal houses using straw as bedding material Ent. agglomerans was most frequent, whereas in animal houses without litter E. coli was mainly found. Airborne Neisseriaceae were isolated very frequently in cow barns with Acinetobacter lowffii as the primary species. Airborne Pseudomonadaceae were found in high concentrations during periods of high air humidity. The results presented may also give some indications on the origin and sources of airborne endotoxins in animal housing.
Thus, the use of S. aureus as an indicator to study the origin and spread of airborne pathogens from chicken houses is potentially useful for enhancing public health and understanding the airborne epidemiology of this pathogen. Meanwhile it can provide evidence for studying the spreading model of airborne pathogens.
Summary
PCR fingerprinting technique was applied to subtype 44 Pasteurella multocida subspecies multocida (P.m.sp.m.) isolates from the respiratory system of pigs. Two single primers were tested for their abilities to generate individual fingerprints by using PCR. Primer 1 (core sequence of the M13 phage) grouped the 44 P.m.sp.m. strains into five distinct fingerprinting profiles, while primer 2 ((GACA)4) grouped them into seven profiles. The results suggest that PCR fingerprinting is an efficient technique to detect DNA polymorphism in the species P.m.sp.m. This technique could be used to differentiate P.m.sp.m. strains of the same capsular serotype.
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