Protective efficacy of Emblica officinalis against Klebsiella pneumoniae induced pneumonia in mice.

BACKGROUND & OBJECTIVES: Emblica officinalis (amla), which is a good source of vitamin C, has been shown to be beneficial due to its immune system enhancing property coupled with its tonifying and antiageing effect. The present study was conducted to evaluate the effect of E. officinalis feeding on the susceptibility of experimental mice to respiratory tract infection induced by Klebsiella pneumoniae. METHODS: The effect of short- (15 days) and long (30 days)-term feeding of amla in mice on the course of K. pneumoniae ATCC43816 infection in lungs was studied, in terms of bacterial colonization, macrophage activity, malondialdehyde (MDA) and nitrite production in broncheoalveolar lavage fluid (BALF). Tumour necrosis factor (TNF)-alpha level in serum was also assessed. RESULTS: Though there was a decrease in bacterial colonization after short-term feeding, it was not significant. On the contrary, the decrease in bacterial load was significant (P < 0.05) on long-term feeding. The operative mechanisms in terms of lipid peroxidation, phagocytosis and nitrite production were studied by estimating their levels in broncheoalveolar lavage fluid (BALF). Maximum decrease in malondialdehyde (MDA) levels and increase in phagocytic activity and nitrite levels on long-term feeding was seen. INTERPRETATION & CONCLUSION: These results suggest that dietary supplementation with amla protects against bacterial colonization of lungs on long-term feeding in experimental model. Further studies need to be conducted to understand the actual mechanism.

Immunoprotective potential of polysaccharide-tetanus toxoid conjugate in Klebsiella pneumoniae induced lobar pneumonia in rats.

The polysaccharide (PS) derived from K. pneumoniae NCTC 5055 lipopolysaccharide (LPS) was covalently linked to tetanus toxoid by using carbodimide with adipic acid dihydrazide as a spacer molecule. The conjugate was found to be non-toxic and non-pyrogenic at 100 microg dose level. At a similar dose, the conjugate did not elicit any local skin reaction on intradermal preparatory injection in rabbits. The conjugate was immunoprotective as was evident from the decrease in relative colonization of bacteria in lungs of immunized rats as compared to the control animals. Immunization with the conjugate resulted in alveolar macrophage activation in terms of their ability to phagocytose bacteria in vitro.

Microbial contamination of weaning foods.

A survey was conducted to determine the prevalence rate of Escherichia coli in different foods being fed to children in the weaning age group. The samples were collected from middle income group (MIG) and high income group (HIG) houses in different localities in Chandigarh. A total of 530 MIG and 525 HIG houses were selected on the basis of availability of children in the weaning age group. A total of 2,016 samples of weaning foods were collected. Isolation of Escherichia coli from MIG and HIG houses was 66.75% and 8.5% respectively. Enterotoxigenic Escherichia coli were detected in 61.47% and 43.5% of the total Escherichia coli isolates from MIG and HIG houses respectively. 'O' serogrouping of the isolates was done and the predominant serotypes found were 06, 0106, 043, 057, 01. The laboratory studies showed that almost all weaning food samples prepared in the laboratory supported the growth of known enterotoxigenic Escherichia coli.

Incidence of klebocinogeny using two indicator systems.

The incidence of bacteriocinogeny among 117 clinical isolates of Klebsiella pneumoniae was examined using two systems of indicators-K. pneumoniae WC indicator and the Abbott-Shannon set of indicators. None of the isolate tested produced bacteriocin active on K. pneumoniae WC while 23 per cent positivity was observed with the Abbott-Shannon indicators. Most of the bacteriocin producers were urinary isolates (53.8%) followed by 15.3 and 30.7 per cent respectively of faecal and miscellaneous isolates. Our results indicate the advantages of using a set of indicators over a single indicator strain.