Trabalho de Conclusão de Curso de Especialização
Resistência antimicrobiana de Staphylococcus spp. isolados de vacas leiteiras da região sul do Brasil
Fecha
2013-07-12Autor
Kowalski, Ananda Paula
Institución
Resumen
The bovine mastitis is an infectious disease of major importance in the dairy farm due to its high occurrence and the economic losses, in addition to the potential risk to public health. Mastitis is characterized by an inflammatory process of the mammary gland and the clinical presentation may vary according to the etiology and severity of the disease, besides the subclinical form shows great occurrence in herds. Intramammary bacterial infections are the major cause of the mastitis, and bacteria belonging to the genus Staphylococcus are involved as main causative agent of subclinical mastitis. Treatment of the disease is predominantly based on the use of antimicrobials; however, the resistance of these pathogens to the drugs commonly used in clinical practice has been a major obstacle to the success of the therapy. This study aimed to analyze the profile of antimicrobial resistance of 2,430 Staphylococcus spp. isolates from milk samples of cows with mastitis during the period 1992-2011. Additionally, it was also observed possible tendency or changes in the behavior of these pathogens against the major drugs used in the treatment of the disease in these two decades. Of the total, 729 Staphylococcus spp. isolates (30%) were susceptible to all antimicrobials tested. In general, there was a reduction in the percentage of resistance during the first decade analyzed (29.2%) compared to the second period (17.1%) (P<0.0004). The highest rates of resistance (P<0.0001) were observed for the class of betalactamics (34.3%), except for cephalexin (6.9%), and tetracyclines (28%). In regarding to the other drugs (norfloxacin, sulfazotrim, gentamicin and neomycin) Staphylococcus spp. isolates showed on average of resistance between 7.6% and 15.7%. In the regression analysis of isolates against antimicrobials during 20 years, it was possible to verify a reduction of resistance to penicillin and ampicillin. However, the micro-organisms tested demonstrated a decrease in the resistance against oxacillin and neomycin during the first decade, followed by an increase in the second period. Regarding to sulfazotrim, there was a tendency to decrease the resistance while to the other antimicrobials, no tendency was highlighted. The results indicated no tendency of increasing resistance of Staphylococcus spp. isolates from bovine mastitis for the most antimicrobial tested, reinforcing the importance of monitoring the resistance patterns of these pathogens, in order to preserve these drugs as a therapeutic reserve.