The emergence of novel or recurring pathogens and the multi-resistance of certain species towards antibiotics have led us to the surveillance of the microbial prevalence in the hospital's air. This study has deployed a methodological demonstration of the prominence of nosocomial pathogens in the University Hospital, Bechar (Algeria). Airborne particles have been collected out of surgery and postoperative halls using the biocollector "M-Air-T". After identifying the collected species, the antibiotic resistance of bacterial strains was evaluated. The following pathogens were identified: Staphylococcus spp., with a dominance of 47.7%, in which we have found that 9% belong to the specific species of S. aureus, followed by 18.7% of Enterobacter spp., and noting an abundance of molds and yeast (Aspergillus spp.,including A. niger, Penicillium spp., Cladosporium spp., Alternaria spp., Rhizopus spp. and Mucor spp.) Antibiotic resistance pattern observed included: for S. aureus to oxacillin, amoxicillin and ampicillin, and for Pseudomonas aeruginosa, and Bacillus spp. to beta-lactam family antibiotics. Factors influencing the risk of nosocomial infection have been found to vary depending on the type of surgery, age, length of preoperative hospitalization, duration of the operation and the number of people in the operating room. So, control of nosocomial infections requires, on one hand a proper isolation of the implicated pathogens in order to clearly otuline this problem, and on the other hand awareness pf resistance patterns for each of these pathogens. It is obvious that in addition to compliance with the basic rules of hygiene, the judicious use of drugs, the implementation of a policy of monitoring and a consortium between clinicians, microbiologists, and hospital pharmacists, remain essential to fight these hospital acquired infections.