Prevalence And Characterization Of Vaginal Lactobacillus Species In Women At Reproductive Age Without Vulvovaginitis [prevalência E Caracterização De Espécies De Lactobacilos Vaginais Em Mulheres Em Idade Reprodutiva Sem Vulvovaginites]

PURPOSE: To identify species of lactobacillus isolated from the vaginal contents of healthy and asymptomatic women, determining the most prevalent species and characterizing them phenotypically. METHODS: Lactobacillus have been isolated in selective milieu from samples of the vaginal contents of 135 women without complaints of vaginal secretion, and with negative laboratorial diagnosis of vaginal infection, followed up at an outpatient clinic. After being identified by multiplex PCR, the isolates have been submitted to RNAr 16S gene sequencing, when necessary. They have also been evaluated concerning the production of lactic acid, H2O2, bacteriocins and the ability to adhere to epithelial cells. RESULTS: eight-three lactobacillus strains were isolated and identified, L. crispatus (30.1%), L. jensenii (26.5%), L. gasseri (22.9%) e L. vaginalis (8.4%), being the prevalent species. Only 20 of those isolates did not present H2O2 production, in detectable amounts. From the 37 strains selected for the test of adhesion to the epithelial cells, 12 presented 50 to 69% of adhesion, 10 presented 70% or more, and the remaining, little or no adhesion at all. None of the tested strains produced bacteriocins. CONCLUSIONS: The lactobacillus species more prevalent in women without vulvovaginitis, isolated in selective culture milieu and identified by molecular methods were L. crispatus, L. jensenii and L. gasseri. 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Reply to: Caution in inferring viral strategies from abundance correlations in marine metagenomes

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Marine viruses discovered via metagenomics shed light on viral strategies throughout the oceans

Marine viruses are key drivers of host diversity, population dynamics and biogeochemicalcycling and contribute to the daily flux of billions of tons of organic matter. Despite recentadvancements in metagenomics, much of their biodiversity remains uncharacterized. Here wereport a data set of 27,346 marine virome contigs that includes 44 complete genomes. Theseoutnumber all currently known phage genomes in marine habitats and include members ofpreviously uncharacterized lineages. We designed a new method for host prediction based onco-occurrence associations that reveals these viruses infect dominant members of the marinemicrobiome such as Prochlorococcus and Pelagibacter. A negative association between hostabundance and the virus-to-host ratio supports the recently proposed Piggyback-the-Winnermodel of reduced phage lysis at higher host densities. An analysis of the abundance patternsof viruses throughout the oceans revealed how marine viral communities adapt to variousseasonal, temperature and photic regimes according to targeted hosts and the diversity ofauxiliary metabolic genes

Lytic to temperate switching of viral communities

Microbial viruses can control host abundances via density-dependent lytic predator–prey dynamics. Less clear is how temperate viruses, which coexist and replicate with their host, influence microbial communities. Here we show that virus-like particles are relatively less abundant at high host densities. This suggests suppressed lysis where established models predict lytic dynamics are favoured. Meta-analysis of published viral and microbial densities showed that this trend was widespread in diverse ecosystems ranging from soil to freshwater to human lungs. Experimental manipulations showed viral densities more consistent with temperate than lytic life cycles at increasing microbial abundance. An analysis of 24 coral reef viromes showed a relative increase in the abundance of hallmark genes encoded by temperate viruses with increased microbial abundance. Based on these four lines of evidence, we propose the Piggyback-the-Winner model wherein temperate dynamics become increasingly important in ecosystems with high microbial densities; thus ‘more microbes, fewer viruses’