Co-infection with Pseudomonas aeruginosa impacts virulence of Staphylococcus aureus and intensifies the severity of infection.

Multi-specie infections display diverse interactions among pathogens that influence the severity of disease. Staphylococcus aureus and Pseudomonas aeruginosa are the two most important opportunistic, nosocomial and drug-resistant pathogens. Poly-infections due to S. aureus and P. aeruginosa are more destructive and result in worse patient outcome than mono-infection. The two organisms are commonly isolated from cystic fibrosis respiratory cultures. Studies demonstrated that S. aureus pre-colonization among cystic fibrosis patients is a hazardous for beginning P. aeruginosa aviation route infection. This work meant to explore the impact of P. aeruginosa on the destructiveness of S. aureus and the level of disease's seriousness by utilizing in-vitro co-culture and host cell model. The outcomes showed that P. aeruginosa outcompetes and suppresses the growth of S. aureus when co-cultured. The host factors expression profile indicated elevated expression of TNFα, IL-6 and IL-12, recommending the unique mechanism of host cell healing inhibition by multispecies. Co-infection resulted in significant increase in IL-8 together with the 10-fold induction of iNOS expression when contrast with S. aureus mono-infection. This indicates that the presence of P. aeruginosa heads the infection towards more severity and complications and delays cell healing process.

In vitro antimicrobial activity of plant fractions against major respiratory pathogens.

From the ancient times, the use of plants is considered as a cure for many diseases and now, they are being used as a new resource for producing agents that could act as alternative to antibiotics. Current work was carried to investigate the antimicrobial potential of 42 different aqueous plant extracts and oils against Staphylococcus aureus, Candida albicans and Pseudomonas aeruginosa. In vitro antimicrobial activity of different concentrations (1.50mg/ml and 0.75mg/ml) of plant fractions was investigated against three clinical isolates: S. aureus, C. albicans and P. aeruginosa by agar well diffusion assay. Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentrations (MBCs) were evaluated by broth dilution and plating method respectively. Among 42 plant fractions, methanol fractions of Cassia fistula leaves and flowers were active against S. aureus. Hexane fractions of Ixora coccinea stalk and leaves, methanol fractions of C. fistula flowers and chloroform fraction of C. fistula leaves were active against C. albicans. Methanol fractions of I. coccinea leaves and stalk were active against P. aeruginosa. The MICs of active fractions were found to be 0.45mg/ml and 0.6mg/ml for P. aeruginosa, S. aureus and C. albicans. The MBCs were found to be 1.50mg/ml for P. aeruginosa, 0.75mg/ml for S. aureus and 1.50mg/ml and 0.75mg/ml for C. albicans. In antibiotic susceptibility testing, all isolates were found to be sensitive to their respective antibiotics.

Oral administration of Lactobacillus acidophilus alleviates exacerbations in Pseudomonas aeruginosa and Staphylococcus aureus pulmonary infections.

Staphylococcus aureus and Pseudomonas aeruginosa are largely the cause of morbidity and mortality in both hospital and community settings. These pathogens remain the important cause of pulmonary infections in patients with cystic fibrosis with a worldwide prevalence. Although, antibiotics are efficient measures of treating bacterial lung infections, the occurrence of antibiotic resistant bacteria has been encouraging the researchers to explore novel therapeutic approaches. It has been discovered that certain lactic acid bacteria possess protective effects against bacterial and viral respiratory infections. The aim of present study was to investigate the capability of orally administered L. acidophilus to ameliorate S. aureus and P. aeruginosa pulmonary infections. Animals were exposed to aerosol of pathogenic suspension. After 24 hours of infection, L. acidophilus treatment was administered orally for 7 consecutive days. Evaluation of tissue bacteriology, histopathology and serum cytokinomics were performed. In parallel, human alveolar A549 cells were utilized to determine possible role of probiotic on pulmonary infections. Oral administration of L. acidophilus significantly (P<0.05) alleviate lung bacterial load and severity of infection as depicted by our histopathological studies. Results obtained from cytokinomics revealed that pro-inflammatory cytokines induced due to lung infection were suppressed in oral probiotic treatment groups. In addition, treatment with L. acidophilus induced murine lung anti inflammatory, IL-10 cytokine level. Current work suggests that orally administered L. acidophilus in mice is able to attenuate S. aureus and P. aeruginosa induced lung cytotoxicity by modulation of host immune response.

Determining the role of a probiotic in the restoration of intestinal microbial balance by molecular and cultural techniques.

The human intestine has a vast variety of microorganisms, and their balance is dependent on several factors. Antibiotics affect microfloral balance and allow naturally opportunistic organisms to multiply. Azithromycin is the most widely used macrolide antibiotic, active against a wide number of pathogens including Pseudomonas aeruginosa and Staphylococcus aureus. It is currently used in the treatment of cystic fibrosis patients. The use of probiotics has advantages in gastrointestinal conditions, including infectious diarrhea and imbalance due to antibiotic use. In this research, the effect of azithromycin on the intestinal microbiota of Sprague Dawley rats and the role of Lactobacillus acidophilus in the restoration of the balance by employing molecular and cultural techniques was investigated. PCR with universal primers targeting the V3 region of the 16S rRNA gene followed by DGGE was used to characterize the overall intestinal microbiota composition. Cultivable fecal bacteria count using microbiological media and semi-quantitative PCR with group-specific primers were also utilized to analyze the effects of antibiotic and probiotic on microflora. We found that the total amount of 16S rRNA gene and fecal aerobic bacterial count was reduced following azithromycin administration along with elimination of non-pathogenic Escherichia coli, but it was restored by the use of the probiotic. The results from PCR with group-specific primers showed that Bacteroides sp was present in the control and probiotic groups, but it was nearly eliminated in the antibiotic group. Moreover, semi-quantitative PCR revealed that the numbers of Enterobacteriaceae were nearly the same in the probiotic group and decreased in the antibiotic group, while Bifidobacterium was significantly increased in the probiotic group and decreased in the antibiotic group (P < 0.05) as compared with that in the control group. Azithromycin-induced dysbiosis can result in prolonged deleterious effects on the host. The present study revealed that the use of lactic acid bacteria particularly L. acidophilus helped to restore intestinal microfloral balance.