Summary
This study was conducted to determine the concentration and frequency distribution of certain airborne micro-organisms on cattle farms and their potential health hazards to farm workers. The samples (60 air samples and 240 hand and nasal swabs from cattle farm workers) were collected from ten cattle farms (five dairy barns and five beef sheds) located in the Sharkia Governorate of Egypt. Air samples were collected for microbiological examination in liquid media using an all-glass impinger whereas those for fungal examination were placed on agar plates using slit air samplers (aeroscopes). The results showed that the overall means of total culturable bacterial and fungal counts were lower in the air of dairy cattle barns than in beef cattle sheds. Identification of the isolated bacteria revealed the recovery of the following species (from dairy cattle barns versus beef cattle sheds): Staphylococcus epidermidis (26.7% vs 36.7%), S. saprophyticus (20% vs 33.3%), S. aureus (10% vs 16.7%), Enterococcus faecalis (23.3% vs 26.7%), Enterobacter agglomerans (23.3 vs 13.3%), Escherichia coli, (16.7% vs 26.7%), Klebsiella oxytoca, (10% vs 16.7%), K. pneumoniae (3.3% vs 0%), Proteus rettegri (6.7% vs 13.3%), P. mirabilis (10% vs 10%), P. vulgaris (3.3% vs 6.7%), Pseudomonas species (6.7% vs 16.7%), respectively). Mycological examination of air samples revealed the presence of Aspergillus fumigatus (46.7% vs 63.3%), A. niger (20% vs 36.7%), A. flavus (13.3% vs 26.7%), Penicillium citrinum (16.7% vs 23.3%), P. viridicatum (13.3% vs 6.7%), P. capsulatum (3.3% vs 0%), Cladosporium spp. (30% vs 56.7%), Alternaria spp. (13.3 vs 23.3%), Mucor spp. (6.7% vs 16.7%), Fusarium spp. (3.3% vs 10%), Absidia spp. (6.7% vs 10%), Curvilaria spp. (10% vs 3.3%), Rhizopus spp. (6.7% vs 13.3%), Scopulariopsis (3.3% vs 6.7%), Epicoccum spp. (0% vs 3.4%) and yeast (13.3% vs 20%), respectively. In addition, microbiological examinations of farm workers revealed heavy contamination of their hands and noses with most of the micro-organisms detected in the air of cattle farms. The results showed that potential airborne microbial risks in beef cattle sheds were greater than in dairies.

Keywords
Air, Bacterium, Beef, Biohazard, Cattle, Dairy, Egypt, Fungi, Public health, Zoonoses.