RESUMO
Oxacillin (methicillin) resistance in methicillin-resistant Staphylococcus aureus (MRSA) is associated with an increased incidence of resistance to other antibiotics, which has increased since it was first reported in 1969. In 1992 a new phenotype of MRSA arose in France; this was characterized by a heterogeneous expression of resistance to oxacillin and susceptibility to various antibiotics, including gentamicin but also tetracycline, minocycline, lincomycin, pristinamycin, co-trimoxazole, rifampin, and fusidic acid. In French hospitals a longitudinal nationwide surveillance of antibiotic resistance in S. aureus has allowed for the detection of changes in antibiotic susceptibility profiles. Seven French clinical laboratories (six from the mainland and one from the West Indies) reported the results of susceptibility testing of 57,347 S. aureus strains isolated in their institutes between 1992 and 1998. Over a 7-year period the incidence of isolation of gentamicin-susceptible MRSA (GS-MRSA) strains has steadily increased to represent, in 1998, 46.8 to 94.4% of the MRSA strains, irrespective of the overall incidence of MRSA. Two predominant types recognized by pulsed-field gel electrophoresis (PFGE) accounted for the majority of the GS-MRSA in different mainland hospitals, both differing from the predominant type observed in the French West Indies. Some GS-MRSA and gentamicin-resistant MRSA (GR-MRSA) strains had closely related PFGE profiles, and hybridization studies confirmed the lack in GS-MRSA of the aac6'-aph2" gene, which confers resistance to all aminoglycosides, with conservation of the ant4' gene, which confers resistance to kanamycin, tobramycin, and amikacin. Thus, it is likely that certain GS-MRSA strains could have emerged from GR-MRSA strains by excision or deletion of the aac6'-aph2" gene.
Assuntos
Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Resistência Microbiana a Medicamentos/genética , Resistência a Múltiplos Medicamentos/genética , Eletroforese em Gel de Campo Pulsado , França/epidemiologia , Deleção de Genes , Genes Bacterianos , Genes MDR , Gentamicinas/farmacologia , Humanos , Resistência a Meticilina/genética , Fenótipo , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Fatores de Tempo , Índias Ocidentais/epidemiologiaRESUMO
Most reports concerning the use of streptokinase (SK) for thrombolysis in myocardial infarction (MI) have employed doses over 1,000,000 units. We evaluated the efficacy of a dose of 500,000 U in 40 patients with acute MI who received full heparin dose before, during and after SK. Thrombolytic effect, as measured by the protamine neutralized thrombin time was shown to be strong in 60% of cases, moderate in 17% and weak in 22%, and this was not modified by larger SK doses. A patent culprit artery was demonstrated at coronary arteriography performed 3 days after SK in 90% of patients. Only one instance of severe bleeding was observed. Thus, a reduced SK dose in association to heparin provides adequate lytic effect and artery patency rate in patients with MI.