Isolation and identification of bacteria from Respiratory tract and Phenotypic and molecular investigation of Hla gene bacteria in Staphylococcus aureus isolated

The study included the collection of 120 clinical samples from the middle ear, nose and pharynx regions, 101 showed positive growth, while 19 isolates did not show growth, and for the period between 1-11-2021 to 1-3-2022, from both sexes in different age groups from hospitals (Samarra General - Dhuluiya year), after conducting microscopic and biochemical tests and using the Vitek compact system 2 device, 32 (31.6%) isolates of S. aureus bacteria 19 (18.8%) isolates of P. aeruginosa 15 (14.8%) isolates of K. pneumonia bacteria 13 (13.13%) isolates of S. pyogenes 7 (6.9%) isolates of E. faecalis 6 (5.9%) isolates of M. catarrhalis 5 (4.9%) isolates of E. coli 4 (3.9%) isolates of P. mirabilis bacteria, the resistance of the diagnosed bacterial isolates to antibiotics was tested by using 10 antibiotics, Azethromycin, Vancomycin, Chloramphenicol, Gentamicin, Penicillin G , Erythromycin, Ceftriaxone, Cephalothin, Amoxcillin clavulinic acid and Cefotaxime. The results of the molecular examination of the gene (Hla) in S. aureus bacteria, which is responsible for hemolysin, showed that 20 isolates of these bacteria were selected because they were clearer and more effective in hemolysis for the purpose of investigating the Hla gene encoded for the production of hemolysin using PCR technique. Responsible for the production of hemolysin, which is one of the virulence factors in S. aureus bacteria, Primer amplification products showed that 19 out of 20 samples possessed this gene (95%), where the bands appeared after being transferred on the agarose gel within the expected region of this gene (535 base pairs).