Buscar en
Enfermedades Infecciosas y Microbiología Clínica (English Edition)
Toda la web
Inicio Enfermedades Infecciosas y Microbiología Clínica (English Edition)
Journal Information
Share
Share
Download PDF
More article options
ePub
Visits
...
Brief report
Effect of subinhibitory concentrations of ampicillin on Listeria monocytogenes
Efecto de las concentraciones subinhibitorias de ampicilina sobre Listeria monocytogenes
Visits
...
Ángel Rodríguez-Villodresa,b, José Antonio Lepea,b,
Corresponding author
jalepe@cica.es

Corresponding author.
, Jesús Blázquezc, Javier Aznard
a Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, Seville, Spain
b Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
c Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
d Department of Microbiology, University of Seville, Seville, Spain
Article information
Abstract
Full Text
Bibliography
Download PDF
Statistics
Figures (1)
Tables (1)
Table 1. Results of colony count (CFU/ml) and number of duplications (ND) of the two strains growing in antibiotic-free medium after the exposure at subinhibitory concentration of ampicillin and the control strain without previous antibiotic exposure.
Abstract

Listeria monocytogenes is an important cause of meningoencephalitis associated with high mortality. The treatment of choice for listeriosis is ampicillin alone or in combination with gentamicin or penicillin G. However, only low ampicillin concentrations are recorded in the central nervous system (CNS). In this study, we analysed the effect of subinhibitory concentrations of ampicillin on the morphology, growth and survival of L. monocytogenes. The non-inhibitory concentration (NIC), the minimum inhibitory concentration (MIC) and the MIC/NIC ratio were determined. Gram and Live/Dead staining showed aggregates of L. monocytogenes cells when grown at subinhibitory concentrations of ampicillin, with >90% of viable cells. The L. monocytogenes strains tested showed an intermediate heteroresistance to ampicillin, characterised by a MIC/NIC ratio of 4. Our results seem to indicate that both intermediate heteroresistance and the formation of aggregates could play a role in the clinical failure of ampicillin in the treatment of CNS infections caused by L. monocytogenes. However, more studies are necessary to elucidate this question.

Keywords:
Listeria monocytogenes
Ampicillin
Subinhibitory concentrations
Aggregates
Heteroresistance
Resumen

Listeria monocytogenes es una importante causa de meningoencefalitis asociada con una elevada mortalidad. El tratamiento de elección para la listeriosis es ampicilina asociada o no a gentamicina o penicilina G. Sin embargo, en el sistema nervioso central (SNC) solo se alcanzan concentraciones bajas de ampicilina. En este estudio, analizamos el efecto de las concentraciones subinhibitorias de ampicilina sobre la morfología, el crecimiento y la supervivencia de L. monocytogenes. Para ello determinamos la concentración no inhibitoria (CNI), la concentración mínima inhibitoria (CMI) y el cociente CMI/CNI. Además, la tinción de Gram y la de vivos y muertos mostraron agregados de L. monocytogenes cuando crece a concentraciones subinhibitorias de ampicilina, con >90% de las células viables. Las cepas de L. monocytogenes testadas mostraron heterorresistencia intermedia a la ampicilina, caracterizada por un cociente CMI/CNI de 4. Nuestros resultados parecen indicar que tanto la formación de agregados como la heterorresistencia intermedia podrían jugar un papel en el fracaso terapéutico observado en las infecciones del SNC causadas por L. monocytogenes. Sin embargo, se necesitan más estudios para aclarar esta cuestión.

Palabras clave:
Listeria monocytogenes
Ampicilina
Concentraciones subinhibitorias
Agregados
Heterorresistencia

Article

These are the options to access the full texts of the publication Enfermedades Infecciosas y Microbiología Clínica (English Edition)
Member

Socio de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica

Para acceder a la revista

Es necesario que lo haga desde la zona privada de la web de la SEIMC, clique aquí

Para realizar los cursos formativos

La actividad estará abierta para socios de la SEIMC. IMPORTANTE, recuerde que requiere registro previo gratuito. Empezar aquí

Subscriber
Subscriber

If you already have your login data, please click here .

If you have forgotten your password you can you can recover it by clicking here and selecting the option “I have forgotten my password”
Subscribe
Subscribe to

Enfermedades Infecciosas y Microbiología Clínica (English Edition)

Purchase
Purchase article

Purchasing article the PDF version will be downloaded

Price 19.34 €

Purchase now
Contact
Phone for subscriptions and reporting of errors
From Monday to Friday from 9 a.m. to 6 p.m. (GMT + 1) except for the months of July and August which will be from 9 a.m. to 3 p.m.
Calls from Spain
932 415 960
Calls from outside Spain
+34 932 415 960
E-mail
es en pt

¿Es usted profesional sanitario apto para prescribir o dispensar medicamentos?

Are you a health professional able to prescribe or dispense drugs?

Você é um profissional de saúde habilitado a prescrever ou dispensar medicamentos