β-Lactamases em Acinetobacter baumannii multirresistente em isolados de pneumonia em um hospital na cidade de uberlândia

Abstract

Acinetobacter baumannii are Gram-negative from the type coccobacillus bacteria, they have high natural antimicrobial resistance and also easily acquire mechanisms of resistance, and therefore it is considered an opportunistic pathogen that survives in different environments, including hospitals, for long periods, especially in Intensive Care Units (ICU), causing serious infections such as in respiratory tract, urinary tract and septicemia. Carbapenem antibiotics were essential for the treatment of these infections, but the production of class B and D β-lactamase enzymes by the microorganism allows inactivation of the drug, giving rise to resistant strains. The point of this study was to determine the resistance of clinical samples of carbapenem-resistant A. baumannii toward other antimicrobials and the production of β-lactamases at Municipal Hospital and Maternity of the Uberlandia, MG. The clinical samples of A. baumannii were evaluated by the antibiograms and submitted to the synergism test with Meropenem discs with and without EDTA, Phenyl Boronic Acid and Cloxacillin. The result of the synergism test was interpreted according to the diameter difference of the inhibition halo. The main isolates were from the ICUs (86%), the main type of sample being tracheal secretions (88.5%). The year with the highest occurrence was 2013 (34.6%), in patients aged 41-80 years (64.1%). There was relationship between tracheal secretion samples and female patients in the ICU and bronchial lavage and male outside the ICU (P <0.05). The resistance to carbapenems occurred along with the quinolones, β-lactam combined with inhibitor and cephalosporins of third and fourth generation, but with 100% sensitivity to Polimixin B. The main resistance mechanisms identified in this study were the MBL-type enzymes (15.4%), followed by loss of porin (11.5%) especially in 2013 and in the sputum sample, and KPC-type enzymes (Klebsiella pneumoniae carbapenemase) in 9%, mainly in the year 2014. Prevention and control measures are increasingly important, including disinfection of the hospital environment, hand hygiene in contact with the patient and correct prescription of antimicrobials, as they contribute to the reduction of infections by multiresistant microorganisms, and phenotypic tests can help with fast diagnosis and efficient containment.