Objectives: The objective of the study is the evaluation of the actual resistance to second, third, and fourth generation cephalosporins over bacterial strains isolated from respiratory infections. The main causes for cephalosporin resistance of pathogenic and conditioned pathogen bacteria are: widespread usage, and impair immune response. Materials and methods: The analyzed specimens were throat swabs and sputum, from adult patients. The tests were performed using disk diffusion technique. We tested the following cephalosporin: From second generation: cefuroxime axetil; from third generation: cefotaxime, ceftazidime, cefpodoxime; Combinations of cephalosporins and beta-lactamase inhibitors: cefotaxime + clavulanic acid; ceftazidim + clavulanic acid; From fourth generation: cefepime; and association cefepime and clavulanic acid. Results: The following bacterial strains were isolated: Staphylococcus aureus, Streptococcus pneumoniae, Group C β-hemolytic Streptococcus, E. coli, Klebsiella pneumoniae and Proteus sp. The Group A. β-hemolytic Streptococcus isolated strains were not tested. For Staphylococcus aureus, E. coli, K. pneumoniae and Proteus, we found a high frequency resistance to 1.

Daptomycin is the first antibiotic in a new class of cyclic lipopeptides, active in vitro against Gram - positive cocci. The mechanism of action is a rapid depolarization of the bacterial membrane potential, loss of cytoplasmic contents, mainly K+ ions and inhibition of protein, DNA and RNA synthesis, followed by the bacterial cell death. There were investigated 112 strains of Gram-positive cocci recommended for daptomycin susceptibility testing. Since the main clinical indications of daptomycin are the severe skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus, vancomicin-resistant enterococci and penicillinresistant Streptococcus spp, we tested daptomycin activity only in these species. The susceptibility tests was performed by Kirby- Bauer disc-diffusion method on Muller-Hinton agar supplemented with Ca 50 mg / ml. (CAMH - Ca 2 + ) as recommended by CLSI. During the period in which we conducted the study we isolated 112 strains of Gram-positive cocci, which we tested sensitivity to daptomycin. Resistance to Daptomycin of Staphylococcus aureus (4.11%) was lower than resistance to vancomycin (6.76%), but higher than the resistance to teicoplanin (2.71%) and linezolid (1.38%). In our study we did not identify daptomycin resistant strains of Enterococcus spp. In severe infections that require more aggressive treatment using active antibiotics on MRSA, daptomycin is a valid therapeutic option, but a susceptibility test is required to ensure effective indication. There were no daptomycin resistant Enterococcus spp. strains