[Are the antimicrobials used in community-acquired respiratory infection useful for preventing transmission of meningococcal disease? In vitro study]. / Son útiles los antimicrobianos utilizados en infección respiratoria de la comunidad para prevenir contactos de enfermedad meningocócica? Estudio in vitro.

This study evaluated whether certain antimicrobial agents used in the treatment of community-acquired respiratory infection were effective against the pathogen Neisseria meningitidis, whose natural habitat is the nasopharyngeal mucosa. Antimicrobial agents commonly use in primary healthcare (betalactams, cephalosporins and macrolides), quinolones and rifampicin were studied by determining minimal inhibitory and bactericidal concentrations, time-kill curves and postantibiotic effect. All of them showed bactericidal activity 24 h after incubation. We therefore believe that they are able to empirically eliminate the causative agent of meningococcal meningitis. However, the only antimicrobial agents capable of inducing a significant postantibiotic effect in the tested strain were the quinolones, which slowed down the growth of the microorganism for over 1 h.

¿Son útiles los antimicrobianos utilizados en infección respiratoria de la comunidad para prevenir contactos de enfermedad meningocócica? Estudio in vitro / Association between MLS antibiotic and tetracycline resistance genes in Streptococcus pneumoniae respiratory infection useful for preventing carriage of meningococcal disease? In vitro study

En el presente estudio valoramos la capacidad que tienen ciertos antimicrobianos utilizados en el tratamiento de la infección respiratoria de la comunidad frente a un patógeno como Neisseria meningitidis, cuyo hábitat natural lo constituye la mucosa nasofaríngea. Mediante determinación de las concentraciones mínimas inhibitorias y bactericidas, las curvas de letalidad y el efecto postantibiótico, se estudiaron los antimicrobianos habitualmente administrados de forma empírica en atención primaria (betalactámicos y macrólidos), quinolonas y rifampicina. Todos mostraron in vitro actividad bactericida a las 24 horas del ensayo, y pensamos que son capaces de eliminar empíricamente de la nasofaringe al agente causal de la meningitis meningocócica. No obstante, los únicos antimicrobianos capaces de inducir efecto postantibiótico significativo en la cepa probada son las quinolonas, que retardan el crecimiento del microorganismo en más de una hora (AU)

[Comparison of the in vitro and in vivo effects of meropenem and ciprofloxacin on the morphology of Escherichia coli and Staphylococcus aureus]. / Comparación del efecto in vitro e in vivo de meropenem y ciprofloxacino sobre la morfología de Escherichia coli y Staphylococcus aureus.

In the treatment of infections, subinhibitory concentrations are commonly present and induce a wide range of effects. Some of these effects have been reported to improve the efficacy of these compounds. One of these effects, the change of the bacterial morphology, was assayed in this study both in vitro and in vivo, and their results were compared. Two antimicrobial agents (meropenem and ciprofloxacin) and two standard Gram-positive and Gram-negative strains (S. aureus y E. coli) were used. The methods employed included the in vitro exposure of microorganisms on Mueller-Hinton agar plates, and the in vivo intraperitoneal infection model in mice. With all the sub-MICs tested, the in vitro results showed that meropenem induced the formation of round cells (spheroplasts) on E. coli, while ciprofloxacin produced filaments. With S. aureus, the two antimicrobial agents induced the formation of cellular aggregates (clusters) with a diameter greater than 1 mm. The in vivo results confirmed those observed in vitro, but to a lesser extent. These results agree with those expected in relation with the mechanisms of action of each drug, and could be important in order to prevent a lost in efficacy when the levels of the drug are below the MIC.