agar and Pneumonia--Pneumococcal

Since the introduction of pneumococcal conjugate vaccine, there have been warnings of an increase in infections caused by non-vaccine type of Streptococcus pneumoniae strains. Among them, nonencapsulated Streptococcus pneumoniae (NESp) has been reported to cause invasive infections, especially in children and the elderly. Due to low virulence, however, basic experimental reports on invasive infections are limited.. We applied a liquid-agar method to establish a mouse model of invasive NESp infection. Mice were intratracheally administered a bacterial suspension including agar. With this technique, we investigated the pathogenicity of NESp and the effect of Pneumococcal surface protein K (PspK), a specific surface protein antigen of NESp. NESp wild-type strain (MNZ11) and NESp pspK-deleted mutant strain (MNZ1131) were used in this study. The survival rate, number of bacteria, cytokine/chemokine levels in the bronchoalveolar lavage fluid, and histology of the lung tissue were evaluated.. Mice that were intratracheally administered MNZ11 developed lethal pneumonia with bacteremia within 48 h. Conversely, MNZ1131 showed predominantly low lethality without significant pro-inflammatory cytokine production. NESp was found to cause severe pneumonia and bacteremia upon reaching the lower respiratory tract, and PspK was a critical factor of NESp for developing invasive infections.. The current study demonstrated the ability of NESp to develop invasive diseases, especially in connection with PspK by use of a mouse pneumonia model.

Topics: Agar; Animals; Bacteremia; Cytokines; Mice; Pneumococcal Infections; Pneumonia, Pneumococcal; Streptococcus pneumoniae; Virulence

Isolation, identification and drug sensitivity assay of microorganisms from pathological materials of 177 patients with nonspecific diseases of the lungs, mainly pneumonia, were performed on blood and selective "chocolate" agars by using Baktofok-MK, a new dry nutrient basis developed by the authors. Blood and "chocolate" agars based on the Hottinger's hydrolysate were used as the control media. It was shown that with the quantitative procedure for inoculating the pathological material, the experimental media based on Baktofok-MK were much more sensitive to growth properties that the control media. That made it possible to detect larger numbers of etiologically important microbial species on the blood agar and to isolate clinical strains of Hemophilus spp. from a larger number of specimens on the "chocolate" agar.

Topics: Agar; Anti-Bacterial Agents; Bronchoalveolar Lavage Fluid; Culture Media; Haemophilus Infections; Haemophilus influenzae; Humans; In Vitro Techniques; Pneumonia; Pneumonia, Pneumococcal; Sputum; Streptococcus pneumoniae