Ampicillin was selected to further study the effect of this antibiotic on the colonization capability of S. pneumoniae and L. fermentum intranasally inoculated in a mice experimental model. The sensitivity of S. pneumoniae and L. fermentum to antibiotics was evaluated by different "in vitro" techniques. The results showed that both microorganisms have a typical pattern of sensitivity to antibiotics in these assays. The "in vivo" experiments showed that the treatment with Ampicillin increased the number of lactobacilli and neumococci in the groups of mice treated only with one of the microorganisms. In those mice treated with Lactobacillus , challenged later with neumococci and treated with Ampicillin, the pathogen in lung decreased on the 4 th day, disappearing completely after on. The histological studies showed that the antibiotic treatment decreased the inflammatory response produced by the pathogen at the lung and trachea levels.
Annals of Clinical Microbiology and Antimicrobials
BioMedCentral
Open Access Research Effect of Ampicillin on the kinetics of colonization ofStreptococcus pneumoniaeandLactobacillus fermentumin the respiratory tract of mice 1 11 1 Rosa Cangemide Gutiérrez, Viviana Santos, Marta Cecilia, Clara Silva 2 and María Elena NaderMacías*
1 2 Address: Facultadde Bioquímica, Química y Farmacia. Universidad Nacional de Tucumán. Tucumán. Argentina andCERELACONICET. Chacabuco 145. 4000. Tucumán. Argentina Email: RosaCangemi de Gutiérrez microbiologia.clinica@unt.edu.ar; Viviana Santos vsantos@unt.edu.ar; Marta Cecilia microbiologia.clinica@unt.edu.ar; Clara Silva microbiologia.clinica@unt.edu.ar; María Elena Nader Macías* mmacias@cerela.org.ar * Corresponding author
S. pneumoniaeL. fermentumprobioticsAmpicillinantimicrobialscolonization
Abstract Ampicillin was selected to further study the effect of this antibiotic on the colonization capability ofS. pneumoniaeandL. fermentumintranasally inoculated in a mice experimental model. The sensitivity ofS. pneumoniaeandL. fermentumto antibiotics was evaluated by different "in vitro" techniques. The results showed that both microorganisms have a typical pattern of sensitivity to antibiotics in these assays. The "in vivo" experiments showed that the treatment with Ampicillin increased the number of lactobacilli andneumococciin the groups of mice treated only with one of the microorganisms. In those mice treated withLactobacillus, challenged later withneumococciand th treated with Ampicillin, the pathogen in lung decreased on the 4day, disappearing completely after on. The histological studies showed that the antibiotic treatment decreased the inflammatory response produced by the pathogen at the lung and trachea levels.
Introduction Respiratory tract infections are commonly caused byStrep tococcus pneumoniae. Extensive antibiotic use for these infections as well as misuse for viral respiratory infections has led to increased penicillin resistance amongst the streptococci [16]. Even though there is a very broad description of the pattern of sensibility to antibiotics of this pathogen and other potentially pathogenic microor ganisms, there are a small number of publications referred to the lactobacilli sensitivity to these types of compounds [710]. The antibiotic treatment modifies the stability of
the normal or indigenous microbiota, producing the dominance of certain microorganisms able sometimes to produce a secondary infection [11]. There are a lot of approaches trying to restore the normal microbiota, or to avoid modifications of the different ecosystems to prevent infections, both for human and animal application. One of the main research areas related to the restoration of the indigenous flora is the application of probiotic microor ganisms [1214].
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