RESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is the major pathogen involved in nosocomial infections, leading to high rates of morbidity and mortality in hospitals worldwide. The methicillin resistance occurs due to the presence of an additional penicillin-binding protein, PBP2a, which has low affinity for beta-lactam antibiotics. In the past few years, vancomycin has been the only antibiotic option for treatment of infections caused by multiresistant MRSA; however, reports of vancomycin-resistant strains have generated great concerns regarding the treatment to overcome these infections. In the present study, we report preliminary results regarding the humoral immune response generated in BALB/c mice by two different doses of naked DNA vaccine containing an internal region, comprising the serine-protease domain, of the PBP2a of MRSA. The immunization procedure consisted of four immunizations given intramuscularly within 15-day intervals. Blood was collect weekly and anti-PBP2a-specific antibodies were screened by ELISA. BALB/c mice immunized with DNA vaccine anti-PBP2a have shown higher antibody titers mainly after the fourth immunization, and intriguingly, no correlation between the humoral immune response and DNA dose was observed. Our results suggest that the DNA vaccine anti-PBP2a induced an immune response by production of specific antibodies anti-MRSA in a non-dose-dependent manner, and it could represent a new and valuable approach to produce specific antibodies for passive immunization to overcome MRSA infections.
Assuntos
Anticorpos Antibacterianos/biossíntese , Resistência a Meticilina/efeitos dos fármacos , Proteínas de Ligação às Penicilinas/imunologia , Peptídeo Sintases/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/imunologia , Vacinas de DNA/administração & dosagem , Animais , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Humanos , Resistência a Meticilina/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Reação em Cadeia da Polimerase , Vacinas Antiestafilocócicas/imunologia , Vacinas de DNA/imunologiaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is the major pathogen involved in nosocomial infections, leading to high rates of morbidity and mortality in hospitals worldwide. The methicillin resistance occurs due to the presence of an additional penicillin-binding protein, PBP2a, which has low affinity for b-lactam antibiotics. In the past few years, vancomycin has been the only antibiotic option for treatment of infections caused by multiresistant MRSA; however, reports of vancomycin-resistant strains have generated great concerns regarding the treatment to overcome these infections. In the present study, we report preliminary results regarding the humoral immune response generated in BALB/c mice by two different doses of naked DNA vaccine containing an internal region, comprising the serine-protease domain, of the PBP2a of MRSA. The immunization procedure consisted of four immunizations given intramuscularly within 15-day intervals. Blood was collect weekly and anti-PBP2a-specific antibodies were screened by ELISA. BALB/c mice immunized with DNA vaccine anti-PBP2a have shown higher antibody titers mainly after the fourth immunization, and intriguingly, no correlation between the humoral immune response and DNA dose was observed. Our results suggest that the DNA vaccine anti-PBP2a induced an immune response by production of specific antibodies anti-MRSA in a non-dose-dependent manner, and it could represent a new and valuable approach to produce specific antibodies for passive immunization to overcome MRSA infections.
Assuntos
Humanos , Animais , Camundongos , Anticorpos Antibacterianos/biossíntese , Resistência a Meticilina/efeitos dos fármacos , Proteínas de Ligação às Penicilinas/imunologia , Peptídeo Sintases/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Staphylococcus aureus/imunologia , Vacinas de DNA/administração & dosagem , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Resistência a Meticilina/imunologia , Camundongos Endogâmicos BALB C , Reação em Cadeia da Polimerase , Vacinas Antiestafilocócicas/imunologia , Vacinas de DNA/imunologiaAssuntos
Infecção Hospitalar/microbiologia , Transmissão de Doença Infecciosa do Profissional para o Paciente/estatística & dados numéricos , Resistência a Meticilina , Doenças Profissionais/microbiologia , Recursos Humanos em Hospital , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus , Brasil/epidemiologia , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Portador Sadio/transmissão , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/transmissão , Eletroforese em Gel de Campo Pulsado , Humanos , Controle de Infecções , Resistência a Meticilina/genética , Doenças Profissionais/epidemiologia , Recursos Humanos em Hospital/estatística & dados numéricos , Reação em Cadeia da Polimerase , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/transmissão , Staphylococcus aureus/genéticaAssuntos
Infecção Hospitalar/epidemiologia , Resistência a Meticilina/genética , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Brasil/epidemiologia , Infecção Hospitalar/transmissão , Eletroforese em Gel de Campo Pulsado , Humanos , Infecções Estafilocócicas/transmissão , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Uruguai/epidemiologiaRESUMO
Two hundred fifty-four methicillin-resistant Staphylococcus aureus (MRSA) strains typed by pulsed-field gel electrophoresis (PFGE) were tested by PCR for the mec-associated hypervariable region (HVR-PCR) to determine their number of direct repeat units (DRUs). Eight different groups of repeats were found among the MRSA strains and compared to 28 pulsotypes classified by PFGE. Some MRSA strains belonging to the same pulsotype showed different numbers of DRUs. HVR-PCR was rapid, easy to perform, and reproducible and has the ability to obtain an unambiguous positive result for each isolate analyzed. However, this technique shows a discriminatory power inferior to that of PFGE. We conclude that PFGE is a more reliable method of typing MRSA than HVR-PCR.
