The microbiota is vital for the development of the immune system and homeostasis. Changes in microbial composition and function, termed dysbiosis, in the respiratory tract and the gut have recently been linked to alterations in immune responses and to disease development in the lungs. In this Opinion article, we review the microbial species that are usually found in healthy gastrointestinal and respiratory tracts, their dysbiosis in disease and interactions with the gut-lung axis. Although the gut-lung axis is only beginning to be understood, emerging evidence indicates that there is potential for manipulation of the gut microbiota in the treatment of lung diseases.

/pdf/emerging-pathogenic-links-between-microbiota-and-the-gut-kqqzn58nt1.pdf

Emerging pathogenic links between microbiota and the gut-lung axis

The intestinal microbiota has increasingly been shown to have a vital role in various aspects of human health. Indeed, several studies have linked alterations in the gut microbiota with the development of different diseases. Among the vast gut bacterial community, Bifidobacterium is a genus which dominates the intestine of healthy breast-fed infants whereas in adulthood the levels are lower but relatively stable. The presence of different species of bifidobacteria changes with age, from the childhood to old age. Bifidobacterium longum, Bifidobacterium breve and Bifidobacterium bifidum are generally dominant in infants whereas Bifidobacterium catenulatum, Bifidobacterium adolescentis and, as well as B. longum are more dominant in adults. Increasingly, evidence is accumulating which shows beneficial effect of supplementation with bifidobacteria for the improvement of human health conditions ranging from protection against infection to different extra- and intra-intestinal positive effects. Moreover, bifidobacteria can be associated with the production of a number of potentially health promoting metabolites including short chain fatty acids, conjugated linoleic acid and bacteriocins. The aim of this mini-review is to describe the bifidobacteria composition changes associated with different stages in life, highlighting their beneficial role, as well as their presence in commonly known disease states.

/pdf/gut-bifidobacteria-populations-in-human-health-and-aging-15gswifkqx.pdf

Gut Bifidobacteria Populations in Human Health and Aging.

Metronidazole, a nitroimidazole, remains a front-line choice for treatment of infections related to inflammatory disorders of the gastrointestinal tract including colitis linked to Clostridium difficile. Despite >60 years of research, the metabolism of metronidazole and associated cytotoxicity is not definitively characterized. Nitroimidazoles are prodrugs that are reductively activated (the nitro group is reduced) under low oxygen tension, leading to imidazole fragmentation and cytotoxicity. It remains unclear if nitroimidazole reduction (activation) contributes to the cytotoxicity profile, or whether subsequent fragmentation of the imidazole ring and formed metabolites alone mediate cytotoxicity. A molecular mechanism underpinning high level (>256 mg/L) bacterial resistance to metronidazole also remains elusive. Considering the widespread use of metronidazole and other nitroimidazoles, this review was undertaken to emphasize the structure-cytotoxicity profile of the numerous metabolites of metronidazole in human and murine models and to examine conflicting reports regarding metabolite-DNA interactions. An alternative hypothesis, that DNA synthesis and repair of existing DNA is indirectly inhibited by metronidazole is proposed. Prokaryotic metabolism of metronidazole is detailed to discuss new resistance mechanisms. Additionally, the review contextualizes the history and current use of metronidazole, rates of metronidazole resistance including metronidazole MDR as well as the biosynthesis of azomycin, the natural precursor of metronidazole. Changes in the gastrointestinal microbiome and the host after metronidazole administration are also reviewed. Finally, novel nitroimidazoles and new antibiotic strategies are discussed.

/pdf/metronidazole-an-update-on-metabolism-structure-cytotoxicity-uttz1wdldy.pdf

Metronidazole: an update on metabolism, structure-cytotoxicity and resistance mechanisms.

Metronidazole resistance and nim genes in anaerobes: A review.

Recent years have brought additional data on the benefits of prebiotics and probiotics treatment in patients with atopic dermatitis. This review includes all the articles published in PubMed, Scopus, Embase and Cochrane databases until 05.06.2018. The terms used for the search were 'prebiotic', 'probiotic', 'atopic dermatitis', 'Severity Scoring of Atopic Dermatitis', and 'SCORAD'. There was an increase of the intestinal permeability reported in patients with atopic dermatitis and a reduction of the cutaneous microbiome diversity. Probiotics modulate the general microbiome and immune status by improving the intestinal barrier; these effects can be responsible for reducing allergic phenomenon and atopic dermatitis severity. We have structured the results by age groups as infants, 1-18 years, adults, and also pregnancy and lactation. Literature does not offer yet answers on the issues such as the optimal dosing, duration needed to see beneficial effects, the optimal time to start the treatment; the personalized use of probiotics according to colonic dysbiosis may be associated with better results. However, most randomized controlled trials and meta-analyzes support the administration of probiotics for at least 8 weeks in order to obtain beneficial effects in improving severity scoring of atopic dermatitis.

/pdf/prebiotics-and-probiotics-in-atopic-dermatitis-review-4mi8jg92ic.pdf

Prebiotics and probiotics in atopic dermatitis (Review)

The relationship between bifidobacteria and allergic asthma and/or allergic dermatitis: a prospective study of 0-3 years-old children in Turkey.

The prevalence of enterotoxin and antibiotic resistance genes in clinical and intestinal Bacteroides fragilis group isolates in Turkey

Background Anaerobic bacteria play an important role in eye infections; however, there is limited epidemiologic data based on the the role of these bacteria in the etiology of keratitis and endophthalmitis. The aim of this re- search is to determine the prevalence of anaerobic bacteria in perforated corneal ulcers of patients with keratitis and endophthalmitis and to evaluate their antimicrobial susceptibilities. Methods Corneal scrapings were taken by the ophthalmologist using sterile needles. For the isolation of anaerobic bacteria, samples were inoculated on specific media and were incubated under anaerobic conditions obtained with Anaero-Gen (Oxoid & Mitsubishi Gas Company) in anaerobic jars (Oxoid USA, Inc. Columbia, MD, USA). The molecular identification of anaerobic bacteria was performed by multiplex PCR and the susceptibilities of an- aerobic bacteria to penicillin, chloramphenicol, and clindamycin were determined with the E test (bioMerieux). Results 51 strains of anaerobic bacteria belonging to four different genuses were detected by multiplex PCR and only 46 strains were isolated by culture. All of them were found susceptible to chloramphenicol whereas penicillin resistance was found in 13.3% of P.anaerobius strains, clindamycin resistance was found in 34.8% of P.acnes and 13.3% of P. anaerobius strains. Additionnaly, one strain of P. granulosum was found resistant to clindamycin, one strain of B. fragilis and one strain of P.melaninogenica were found resistant to penicillin and clindamycin. Conclusions Routine analyses of anaerobes in perforated corneal ulcers is inevitable and usage of appropriate molecular methods, for the detection of bacteria responsible from severe infections which might not be deter- mined by cultivation, may serve for the early decision of the appropriate treatment. Taking into account the in- creasing antimicrobial resistance of anaerobic bacteria, alternative eye specific antibiotics effective against anaer- obes are needed to achieve a successful treatment.

Prevalence and antimicrobial susceptibilities of anaerobic bacteria isolated from perforated corneal ulcers by culture and multiplex PCR: an evaluation in cases with keratitis and endophthalmitis.

Achille Aime Kangaba

Papers

The relationship between bifidobacteria and allergic asthma and/or allergic dermatitis: a prospective study of 0-3 years-old children in Turkey.

The prevalence of enterotoxin and antibiotic resistance genes in clinical and intestinal Bacteroides fragilis group isolates in Turkey

Prevalence and antimicrobial susceptibilities of anaerobic bacteria isolated from perforated corneal ulcers by culture and multiplex PCR: an evaluation in cases with keratitis and endophthalmitis.