The effect of dietary fish oil on survival after infection with Klebsiella pneumoniae or Streptococcus pneumoniae

Inhibition performance of almond shell hydrochar-based fish oil emulsion gel on Klebsiella pneumonia inoculated fish skin and its characteristics

In this study, the inhibition potential against Klebsiella pneumoniae (K. pneumoniae) and the characterization of fish oil (FO) emulsion gel (EGE) containing almond shell hydrochar (AH) were investigated. Oily water of mullet liver was emulsified using tween 80, then gelled using gelatin and finally immobilized into hydrochar using an ultrasonic homogenizer. Characteristics and surface analysis of hydrochar-based emulsion gel (HEGE) were examined using FTIR and SEM. Stability, particle size distribution and zeta potential of HEGE were measured. In this study, a zeta potential of -18.46 indicated that HEGE was more stable than EGE (35.7 mV). The addition of hydrochar to the emulsion gel containing micro-droplets enabled the structure to become fully layered and stable. Time-dependent inactivation of K. pneumoniae exposed to HEGE and fixed in 6 mm-fish skin was evaluated for the first time in this study. While the highest log reduction and percent reduction in the bacterial count were achieved within 5 min with 0.87 CFU/cm2 and 86.60% with EGE, the lowest log reduction and percent reduction were achieved with 0.003 CFU/cm2 and 0.082% with HEGE in 30 min. In conclusion, the almond shell hydrochar-immobilized emulsion gel is a functional adsorbent that can inhibit K. pneumonia, and its stability and performance make it a unique candidate for further studies in this field.

Differential fatty acid analysis of cerebrospinal fluid in infants and young children with suspected meningitis

PURPOSE

Meningitis is relatively common in infants and young children and can cause permanent brain damage. The aim of this study was to determine whether meningitis is associated with fatty acids in cerebrospinal fluid (CSF).

METHODS

CSF samples from children between 3 months and 6 years of age admitted to the Tabriz public hospitals who met clinical criteria of meningitis were collected at enrollment. A total of 81 samples were analyzed for fatty acid profile by gas-liquid chromatography.

RESULTS

Children with a purulent meningitis demonstrated a higher percentage of oleic acid (p < 0.05, >10 %) and lower percentages of omega-3 polyunsaturated fatty acids (p < 0.001, <-40 %) than aseptic meningitis and nonmeningitis groups did. There was an inverse relationship between CSF long-chain omega-3 fatty acids and the total number of leukocytes and differential counts of neutrophils and lymphocytes in the purulent meningitis group. Moreover, significantly lower omega-3 fatty acids (p = 0.001, -37 %) and higher ratio of n-6/n-3 (p = 0.02, -29 %) were found in patients with purulent meningitis with sepsis than in those with meningitis and no sepsis.

CONCLUSIONS

This study provides evidence that purulent meningitis and its complication with sepsis are associated with important disturbances in CSF fatty acids, mainly deficiency in long-chain omega-3 polyunsaturated fatty acids.

Dietary supplementation with omega-3 polyunsaturated fatty acids ameliorates acute pneumonia induced by Klebsiella pneumoniae in BALB/c mice

The immune benefits associated with the optimal intake of dietary fatty acids are widely known. The objective of the present investigation was to elucidate the role of omega-3 polyunsaturated fatty acids (n-3 PUFA) food source on acute pneumonia induced by Klebsiella pneumoniae. Three different n-3 PUFA preparations (cod liver oil, Maxigard, and flaxseed oil) were orally supplemented and infection was induced in different groups of experimental mice. Mice fed olive oil and normal saline served as oil and saline controls, respectively. After 2 weeks of fatty acid feeding, no effect on the establishment of infection was observed when acute pneumonia was induced in animals. On the other hand, 6 weeks of n-3 PUFA administration was found to improve resistance in mice, as reduced lung bacterial load coupled with significant improvement in pathology was seen in infected mice. Alveolar macrophages collected from all 3 groups of mice fed n-3 PUFA exhibited a significant decrease in the level of apoptosis following infection with K. pneumoniae and an enhanced in vitro phagocytic potential for the pathogen. Lower lung levels of nitric oxide, malondialdehyde, and lactate dehydrogenase were associated with a decrease in the severity of tissue damage. There was a significant increase in the lung levels of pro-inflammatory cytokines (tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β)). No significant change was observed in the levels of interleukin-10 (IL-10). This study highlights that dietary n-3 PUFA supplementation exerts an overall beneficial effect against acute experimental pneumonia. This mechanism is operative through upregulation of nonspecific and specific immune defenses of the host.

Assessment of interleukin-12, gamma interferon, and tumor necrosis factor alpha secretion in sera from mice fed with dietary lipids during different stages of Listeria monocytogenes infection

Recent experimental observations have determined that long-chain n-3 polyunsaturated fatty acids suppress immune functions and are involved in the reduction of infectious disease resistance. BALB/c mice were fed for 4 weeks with one of four diets containing either olive oil (OO), fish oil (FO), hydrogenated coconut oil, or a low fat level. Interleukin-12p70 (IL-12p70), gamma interferon (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha) production in the sera of mice fed these diets and challenged with Listeria monocytogenes were determined by enzyme-linked immunosorbent assay. In addition, bacterial counts from spleens of mice were carried out at 24, 72, or 96 h of infection. Here, we quantified an initial diminution of production of both IL-12p70 and IFN-gamma, which appear to play an important role in the reduction of host resistance to L. monocytogenes infection. In addition, an efficient elimination of L. monocytogenes was observed in spleens of mice fed a diet containing OO at 96 h of infection, despite reductions in IL-12p70 and TNF-alpha production, suggesting an improvement of immune resistance. Overall, our results indicate that the initial reduction of both IL-12 and IFN-gamma production before L. monocytogenes infection represents the most relevant event that corroborates the impairment of immune resistance by n-3 polyunsaturated fatty acids during the different stages of infection. However, we speculate that the modulation of other cytokines must be also involved in this response, because the alteration of cytokine production in mice fed an FO diet in a late phase of L. monocytogenes infection was similar to that in mice fed OO, whereas the ability to eliminate this bacterium from the spleen was improved in the latter group.