Background: Reducing antibiotics overuse in animal agriculture is one key in combat against the spread of antibiotic resistance. Probiotics are a potential replacement of antibiotics in animal feed; however, it is not clear whether and how probiotics and antibiotics differ in impact on physiology and microbial ecology of host animals. Results: Host phenotype and fecal microbiota of broilers with either antibiotics or probiotics as feed additive were simultaneously sampled at four time points from birth to slaughter and then compared. Probiotic feeding resulted in a lower feed conversion ratio (FCR) and induced the highest level of immunity response, suggesting greater economic benefits in broiler farming. Probiotic use but not antibiotic use recapitulated the characteristics of age-dependent development of gut microbiota in the control group. The maturation of intestinal microbiota was greatly accelerated by probiotic feeding, yet significantly retarded and eventually delayed by antibiotic feeding. LP-8 stimulated the growth of many intestinal Lactobacillus spp. and led to an altered bacterial correlation network where Lactobacillus spp. are negatively correlated with 14 genera and positively linked with none, yet from the start antibiotic feeding featured a less-organized network where such inter-genera interactions were fewer and weaker. Consistently, microbiota-encoded functions as revealed by metagenome sequencing were highly distinct between the two groups. Thus, "intestinal microbiota maturation index" was proposed to quantitatively compare impact of feed additives on animal microecology. Conclusions: Our results reveal a tremendous potential of probiotics as antibiotics' substitute in poultry farming.

BackgroundMastitis, which affects nearly all lactating mammals including human, is generally thought to be caused by local infection of the mammary glands. For treatment, antibiotics are commonly prescribed, which however are of concern in both treatment efficacy and neonate safety. Here, using bovine mastitis which is the most costly disease in the dairy industry as a model, we showed that intestinal microbiota alone can lead to mastitis.ResultsFecal microbiota transplantation (FMT) from mastitis, but not healthy cows, to germ-free (GF) mice resulted in mastitis symptoms in mammary gland and inflammations in serum, spleen, and colon. Probiotic intake in parallel with FMT from diseased cows led to relieved mastitis symptoms in mice, by shifting the murine intestinal microbiota to a state that is functionally distinct from either healthy or diseased microbiota yet structurally similar to the latter. Despite conservation in mastitis symptoms, diseased cows and mice shared few mastitis-associated bacterial organismal or functional markers, suggesting striking divergence in mastitis-associated intestinal microbiota among lactating mammals. Moreover, an “amplification effect” of disease-health distinction in both microbiota structure and function was apparent during the cow-to-mouse FMT.ConclusionsHence, dysbiosis of intestinal microbiota may be one cause of mastitis, and probiotics that restore intestinal microbiota function are an effective and safe strategy to treat mastitis.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0578-1) contains supplementary material, which is available to authorized users.

No abstract

BackgroundBloodstream infections due to Candida species cause significant morbidity and mortality, and the epidemiology of Candida infection is changing. Surveillance for candidemia is necessary to detect trends in species distribution and antifungal resistance.MethodsThe medical and electronic records of all patients who had candidemia at the authors’ hospital from 2009 to 2011 were reviewed for demographic data and clinical information, including the infecting Candida species, resistance to antifungals and survival, and the presence of risk factors associated with candidemia.ResultsA total of 133 distinct episodes of candidemia were identified over the study period. The annual incidence of candidemia ranged between 0.71 and 0.85 cases/1000 hospital discharges. The most frequent Candida species were C. tropicalis (28.6%), followed by C. albicans (23.3%) and C. parapsilosis (19.5%). The rates of susceptibility to antifungal agents were as followed: voriconazole (97.8%), itraconazole (69.5%), fluconazole (46.1%), ketoconazole (38.9%). Out of 131 evaluable patients, 34 (26.0%) died within 30 days from the onset of candidemia. C. tropicalis candidemia was associated with the highest mortality rate (44.7%). Regarding the crude mortality in the different units, patients in Hemato-Oncology ward had the highest mortality rate (66.7%), followed by patients in cardiovascular wards and ICU (57.1% and 25.6%, respectively). Predictors of 30-day mortality were identified by uni- and multivariate analyses. Complicated abdominal surgery, presence of central venous catheter (CVC), neutropenia, candidemia due to C. tropicalis and poor treatment with fluconazole were significantly associated with the 30-day mortality. Presence of CVC (odds ratio[OR] = 4.177; 95% confidence interval [CI] = 1.698 to 10.278; P = 0.002) was the only independent predictor for mortality in the multivariate analysis.ConclusionThis report provides baseline data for future epidemiological and susceptibility studies and for the mortality rates associated with candidemia in our hospital. The knowledge of the local epidemiological trends in Candida species isolated in blood cultures is important to guide therapeutic choices.

No abstract

Chloroplast development requires the coordinated action of various proteins, many of which remain to be identified. Here, we report two novel genes, Mesophyll-cell RNAi Library line 7 (MRL7) and MRL7-Like (MRL7-L), that are involved in this process. An Arabidopsis knock-down transgenic plant (MRL7-RNAi) with delayed-greening phenotype was isolated from an RNA interference (RNAi) transformant library. Cotyledons and young leaves of MRL7-RNAi were pale in seedlings and gradually greened as the plant matured, while a knock-out in the MRL7 gene was seedling lethal. The MRL7 protein was shown to co-localize with a marker protein for nucleoids in chloroplasts, indicative of a role for the protein in chloroplast nucleic acid metabolism. Accordingly, chloroplast development was arrested upon loss of MRL7 function and the expression of plastid-encoded genes transcribed by plastid-encoded RNA polymerase (PEP) was significantly reduced in MRL7 knock-down and knock-out plants. A paralog of MRL7 (MRL7-L) was identified in the Arabidopsis genome. Both MRL7 and MRL7-L are only found in land plants and encode previously uncharacterized proteins without any known conserved domain. Like MRL7, knock-down of MRL7-L also resulted in a virescent phenotype, and a similar effect on plastid gene expression. However, the MRL7-L protein was localized to the chloroplast stroma. Taken together, our data indicate that the two paralogous proteins MRL7 and MRL7-L have essential but distinct roles during early chloroplast development and are involved in regulation of plastid gene expression.

ObjectiveEarly childhood caries (ECC) has become a prevalent public health problem among Chinese preschool children. The bacterial microflora is considered to be an important factor in the formation and progress of dental caries. However, high-throughput and large-scale studies of the primary dentition are lacking. The present study aimed to compare oral microbial profiles between children with severe ECC (SECC) and caries-free children.MethodsBoth saliva and supragingival plaque samples were obtained from children with SECC (n = 20) and caries-free children (n = 20) aged 3 to 4 years. The samples were assayed using the Human Oral Microbe Identification Microarray (HOMIM).ResultsA total of 379 bacterial species were detected in both the saliva and supragingival plaque samples from all children. Thirteen (including Streptococcus) and two (Streptococcus and Actinomyces) bacterial species in supragingival plaque and saliva, respectively, showed significant differences in prevalence between the two groups. Of these, the frequency of Streptococcus mutans detection was significantly higher in both saliva (p = 0.026) and plaque (p = 0.006) samples from the SECC group than in those from the caries-free group.ConclusionsThe findings of our study revealed differences in the oral microbiota between the SECC and caries-free groups Several genera, including Streptococcus, Porphyromonas, and Actinomyces, are strongly associated with SECC and can be potential biomarkers of dental caries in the primary dentition.

No abstract