Secreted frizzled-related protein 2 ameliorates diabetic cardiomyopathy by activating mitophagy.

OBJECTIVES: Secreted frizzled-related protein 2 (SFRP2), a novel adipokine that used to be considered an inhibitor of the canonical Wnt pathway, may play a protective role in metabolic disorders. However, its effect on diabetic cardiomyopathy was still unclear. Accumulating evidence indicates that mitophagy can protect cardiac function in the diabetic heart. The present study aimed to explore the roles of SFRP2 on diabetic cardiomyopathy, focusing on the effects and mechanisms for regulating mitophagy. METHODS: Wild-type H9c2 cells, Sfrp2 overexpression and knockdown H9c2 cells were exposed to a glucolipotoxic milieu. Reactive oxygen species (ROS) production, cell viability, apoptosis, mitophagy and lysosomal activity were detected. The interaction of SFRP2 with frizzled 5 (FZD5), and its effect on expression and intracellular localization of transcription factor EB (TFEB) and ß-catenin were also explored. Diabetic rats and Sfrp2 overexpression diabetic rats were constructed to further document the findings from the in vitro study. RESULTS: The expression of SFRP2 was low and mitophagy was inhibited in H9c2 cells in a glucolipotoxic milieu. Sfrp2 overexpression activated mitophagy and reduced H9c2 cells injury, whereas Sfrp2 deficiency inhibited mitophagy and worsened this injury. Consistent with the in vitro findings, Sfrp2 overexpression ameliorated the impairment in cardiac function of diabetic rats by activating mitophagy. Sfrp2 overexpression upregulated the expression of calcineurin and TFEB, but did not affect ß-catenin in vitro and in vivo. The calcineurin inhibitor tacrolimus can inhibit mitophagy and worsen cell injury in Sfrp2 overexpression H9c2 cells. Furthermore, we found that FZD5 is required for the SFRP2-induced activation of the calcineurin/TFEB pathway and interacts with SFRP2 in H9c2 cells. Transfection with small interfering RNA targeting FZD5 opposed the effects of Sfrp2 overexpression on mitophagy and cell survival in a glucolipotoxic environment. CONCLUSIONS: SFRP2 can protect the diabetic heart by interacting with FZD5 and activating the calcineurin/TFEB pathway to upregulate mitophagy in H9c2 cells.

Helicobacter pylori infection and risk of cardiovascular disease.

BACKGROUND: Whether Helicobacter pylori (H. pylori) infection is associated with an increased risk of cardiovascular disease (CVD) remains controversial. This study aimed to investigate the association between H. pylori infection and the risk of CVD. METHODS: Potentially related studies were searched in the electronic databases, including PubMed, EMBASE and Cochrane Library, from inception to 31 August 2022. Observational cohort studies that reported the multivariable-adjusted relative risks (RRs) for composite CVD, CHD, stroke, or all-cause mortality associated with H. pylori infection were included in the meta-analysis, using random-effects models. RESULTS: Forty-one cohort studies with 230,288 participants were included. After a median follow-up duration of 6.3 years, H. pylori infection was associated with a mildly increased risk of composite CVD (RR 1.10, 95% CI 1.03, 1.18) and coronary heart disease (RR 1.10, 95% CI 1.02, 1.18) compared with those without H. pylori infection. No significant association was observed between H. pylori infection and risk of stroke (RR 1.08, 95% CI 0.94, 1.23) or all-cause mortality (RR 1.02, 95% CI 0.90, 1.16). Compared with cytotoxin-associated gene-A (CagA) negative H. pylori infection, the risk of CVD was significantly increased in patients with CagA positive H. pylori infection (RR 1.58, 95% CI 1.03, 2.41). CONCLUSIONS: Helicobacter pylori infection is associated with a mildly increased risk of CVD. It may be of great public health and clinical significance to screen H. pylori infection in patients with a high risk of CVD.

Stains therapy and the risk of all bleeding and intracranial hemorrhage: A meta-analysis of randomized controlled studies.

AIMS: Statins had been used as a cornerstone in the primary and secondary prevention of cardiovascular disease. Widespread attention had been given to the risk of bleeding, especially intracranial hemorrhage (ICH) in patients receiving statins therapy. This study aimed to determine whether statins treatment was associated with the risk of bleeding and ICH in randomized controlled trials (RCTs). MATERIALS AND METHODS: Electronic databases were searched for studies up to September 8, 2022. Articles from RCTs were included in the meta-analysis if they reported the bleeding events associated with the treatment of statins or placebo/nonstatin treatment. The risk ratios (RR) of total bleeding and ICH were pooled from the number of patients with each outcome in the statins and control groups from the included studies. RESULTS: Twenty-nine studies comprising 145,929 individuals (2437 incident bleeding cases) were included in the meta-analysis. After a median follow-up duration of 3.65 years, statins treatment was not associated with the risk of all bleeding (RR = 1.03, 95% CI 0.93-1.15). Furthermore, in 26 studies comprising 144,177 participants, after a median follow-up duration of 3.95 years, statins treatment was not associated with the risk of ICH (RR = 1.05, 95% CI 0.84-1.31). Although in the subgroup analysis with patients with prior stroke, statins treatment showed an increased risk of ICH (RR = 1.47, 95% CI 1.07-2.01), sensitivity analysis showed that the result was unstable, which may be mainly driven by the SPARCL study. CONCLUSIONS: Statins therapy is not associated with the risk of all bleeding and ICH. Although a mildly increased risk of ICH in patients with prior stroke is observed, which may be caused by chance finding and warrant further documentation.

Association between the ratio of serum eicosapentaenoic acid to arachidonic acid and risk of coronary artery disease in young Chinese patients.

Objective: Long-chain (LC) omega-3 PUFAs, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may play an anti-inflammatory effect and decrease the risk of coronary artery disease (CAD). In contrast, omega-6 PUFA, mainly arachidonic acid (AA), has pro-inflammatory and pro-aggregatory effects, which may increase the risk of CAD. This study evaluated the associations between EPA, DHA, AA, and their ratios (EPA/AA and DHA/AA) with the risk of CAD in young Chinese patients. Methods: A total of 182 young patients with CAD and 143 age-matched controls were included. Traditional cardiovascular risk factors were recorded. Serum EPA, DHA and AA were measured by ultra-performance liquid chromatography-mass spectrometry. Results: The level of AA was significantly higher, while the level of EPA was lower in the CAD group than that in the control group. There was no significant difference in DHA level in the two groups. Both the ratios of EPA/AA and DHA/AA were lower in the CAD group than that in the control. Multivariate logistic regression analysis showed that higher serum AA level was associated with the increased risk of CAD, while EPA was a protective factor for CAD. There was no significant association between DHA level and the risk of CAD. Although both higher ratios of EPA/AA [per tertile increment, adjusted odds ratios (ORs) (OR) 0.356, 95% confidence intervals (CI) 0.247-0.513] and DHA/AA (adjusted OR = 0.465, 95%CI = 0.332-0.653) were associated with a lower risk of CAD in young patients. Receiver operating characteristic (ROC) curve analysis showed that compared with AA, the diagnostic value was increased in EPA/AA, but not in DHA/AA. Conclusion: EPA, but not DHA may play a protective role in CAD, while AA may be associated with the increased risk of CAD in young Chinese patients. The ratio of EPA/AA can increase the predictive value for diagnosing CAD than EPA or AA alone.

Prevalence and Related Factors of White Coat Hypertension and Masked Hypertension in Shunde District, Southern China.

Background: White coat hypertension (WCH) and masked hypertension (MH) can increase the risk of target organ damage. Home blood pressure monitoring is an important method for detecting WCH and MH. However, the prevalence and related factors of WCH and MH in China have been rarely reported. Objective: To explore the prevalence and related factors associated with white coat hypertension (WCH) and masked hypertension (MH) in Shunde District, Southern China. Methods: This study recruited subjects from the Physical Examination Center in Shunde Hospital, Southern Medical University. Office blood pressure and home blood pressure values were collected using the home blood pressure monitor with telemedicine device and office blood pressure monitor, and the prevalence of WCH and MH was calculated by the values. Multivariate logistic regression was used to explore the related factors for WCH and MH. Results: Four-hundred and sixty-one participants (61% male), with an average age of 49 years, were included. The prevalence of WCH and MH was 5.1 and 15.2%, respectively. Multivariate logistic regression analysis showed that smoking (OR = 4.71, 95% CI = 1.05-21.15) and family history of coronary heart disease (OR = 4.51, 95% CI = 1.08-18.93) were associated with higher odds of WCH. The associated factors for higher odds of MH were smoking (OR = 2.83, 95% CI = 1.11-7.23), family history of hypertension (OR = 2.17, 95% CI = 1.11-4.26) and family history of coronary heart disease (OR = 2.82, 95% CI = 1.07-7.45). Conclusion: WCH and MH are highly prevalent in the Physical Examination Center in Shunde Hospital, Southern Medical University. We found smoking and family history of coronary heart disease were related factors for WCH, and smoking, family history of hypertension and coronary heart disease were associated with the odds of MH. Home blood pressure monitoring with a telemedicine device should be recommended to identity abnormal BP phenotype.

Long-chain omega-3 polyunsaturated fatty acids and the risk of heart failure.

Aims: Adequate intake of long-chain (LC) omega-3 polyunsaturated fatty acids (n-3 PUFAs) is considered important for cardiovascular health. However, the effects of LC n-3 PUFAs on the risk of heart failure (HF) remain unclear. This systematic review and meta-analysis aimed to determine the role of LC n-3 PUFAs in the incidence of HF. Materials and Methods: Electronic databases were searched for studies up to 31 July 2021. Studies were included for the meta-analysis if they reported the adjusted associations between different dietary intakes or circulating concentrations of LC n-3 PUFAs and the risk of HF. A random-effect model was used to calculate the pooled estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for higher LC n-3 PUFA concentrations. Results: Thirteen studies were included in the meta-analysis. Eight studies comprising 316,698 individuals (11,244 incident HF cases), with a median follow-up of 10.7 years, showed that a higher dietary intake of LC n-3 PUFAs was associated with a lower risk of HF (highest versus lowest quintile: HR = 0.84, 95% CI = 0.75-0.94). Six studies, comprising 17,163 participants (2520 HF cases) with a median follow-up of 9.7 years, showed that higher circulating LC n-3 PUFA concentrations were associated with a lower risk of HF (highest versus lowest quintile: HR = 0.59, 95% CI = 0.39-0.91). Higher circulating docosahexaenoic acid concentrations were associated with a decreased risk of HF (top versus bottom quintile: HR = 0.44, 95% CI = 0.26-0.77). The associations between eicosapentaenoic acid (HR = 0.58, 95% CI = 0.26-1.25), docosahexaenoic acid (HR = 0.66, 95% CI = 0.24-1.82), and the risk of HF were not significant. Conclusion: High LC n-3 PUFA concentrations measured by dietary intake or circulating biomarkers are associated with a lower risk of developing HF.

Effects of statins in primary and secondary prevention for venous thromboembolism events: A meta analysis.

OBJECTIVE: The associations between statins use and incidence or recurrence of venous thromboembolism (VTE) are controversial. We aimed to conduct a meta-analysis to reconcile the conflicting results. METHODS: We searched PubMed, Embase and Cochrane Library for studies published from database inception until May 31, 2021. Cohort studies and Randomized Controlled Trials that reported incidence or recurrence of VTE using statins compared with placebo or non-statins were included for meta-analysis. RESULTS: A total of 43 studies comprising over 8.6 million participants were included for analysis. The median follow-up duration was 38.1 months. Compared with no statins treatment, statins appeared to have a protective effect in primary prevention of VTE (RR 0.78, 95% CI 0.72-0.85), but significant heterogeneity was found among included studies (I2 = 81%). Statins was also associated with a 26% reduced risk of recurrent VTE (RR 0.74, 95% CI 0.70-0.78), even in patients receiving anticoagulant therapy (RR 0.77, 95% CI 0.65-0.92). In patients with a history of VTE, statins was associated with a reduced risk of bleeding and all cause mortality. The NNT of statins to prevent one case of VTE in the cancer population, and one case of recurrent VTE in patients with a history of VTE was 103.1 and 90.7 person-years respectively. CONCLUSION: In high-risk patients, statins treatment may reduce the incidence of VTE. Statins can also reduce the risk of recurrent VTE and all-cause mortality in patients with a history of VTE.

Antiviral effect of a bacteriophage on murine norovirus replication via modulation of the innate immune response.

Bacteriophages (phages) are viruses of bacteria. Despite the growing progress in research on phage interactions with eukaryotic cells, our understanding of the roles of phages and their potential implications remains incomplete. The objective of this study was to investigate the effects of the Staphylococcus aureus phage vB_SauM_JS25 on murine norovirus (MNV) replication. Experiments were performed using the RAW 264.7 cell line. After phage treatment, MNV multiplication was significantly inhibited, as indicated by real-time quantitative polymerase chain reaction (RT-qPCR) analysis, western blotting, the 50% tissue culture infectious dose and immunofluorescence. Furthermore, we revealed transcriptional changes in phage/MNV co-incubated RAW 264.7 cells through RNA sequencing (RNA-seq) and bioinformatic analysis. Our subsequent analyses revealed that the innate immune response might play an important role in restriction of MNV replication, such as the cellular response to IFN-γ and response to IFN-γ. Additionally, gene expression of IL-10, Arg-1, Ccl22, GBP2, GBP3, GBP5, and GBP7 was increased significantly, which indicated a strong correlation between RT-qPCR and RNA-seq results. Furthermore, phage treatment activated guanylate binding proteins (GBPs), as revealed by RT-qPCR analysis, western blotting, and confocal microscopy. Taken together, these data suggest that the phage affects the innate response, such as the IFN-inducible GTPases and GBPs, and therefore exerts an antiviral effect in vitro. Collectively, our findings provide insights into the interactions of immune cells and phages, which establish phage-based antiviral effects.

Non-alcoholic fatty liver disease is associated with increased risk of chronic kidney disease.

BACKGROUND AND AIMS: Whether non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of incident chronic kidney disease (CKD) independent of established cardio-renal risk factors remains controversial. We aimed to provide a quantitative estimate of the association and strength between NAFLD and risk of CKD after adjustment for multiple cardio-renal risk factors. METHODS: We searched electronic databases (PubMed, Embase, and Google Scholar) for studies published from database inception until 30 November 2020. Analysis included cohort studies that reported multivariable-adjusted risk ratios [including odds ratios, relative risks (RRs), or hazard ratios] and 95% confidence intervals (CIs) for CKD of NAFLD compared with individuals without NAFLD. RESULTS: A total of 11 cohort studies were included comprising 1,198,242 participants (46.3% women) for analysis. The median follow-up duration was 3.7 years, with 31,922 cases of incident CKD. Compared with individuals without NAFLD, unadjusted models showed that NAFLD was associated with a higher risk of CKD (RR 1.54, 95% CI 1.38-1.71). After adjusting for multiple cardio-renal risk factors, the CKD risk was still significantly increased in patients with NAFLD (RR 1.39, 95% CI 1.27-1.52). Compared with individuals without NAFLD, the adjusted absolute risk increase in NAFLD for CKD was 5.1 (95% CI 3.5-6.8) per 1000 person-years. CONCLUSION: NAFLD is associated with an increased risk of incident CKD independent of established cardio-renal risk factors.

Association between prediabetes and adverse outcomes in heart failure.

AIMS: Patients with heart failure (HF) and with diabetes experienced significantly worse outcomes than those without diabetes. However, data on the prognostic impact of prediabetes in HF are inconclusive. This meta-analysis aimed to explore the association between prediabetes and the risk of all-cause mortality and adverse cardiac outcomes in patients with HF. MATERIALS AND METHODS: We searched multiple electronic databases (PubMed, Embase and Google Scholar) for relevant studies up to 31 March 2021. Studies were included for analysis if multivariable adjusted relative risks of adverse outcomes were reported in patients with prediabetes and with HF compared with those with normoglycaemia. Random-effects models were used to calculate the pooled hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Twelve studies comprising 28 643 patients with HF reported the risk of all-cause mortality and cardiac outcomes associated with prediabetes. The prevalence of prediabetes ranged from 9.6% to 37.2%. After a median follow-up duration of 2.3 years, patients with HF and with prediabetes were associated with an increased risk of all-cause mortality (HR 1.29, 95% CI 1.06-1.58), cardiovascular mortality (HR 1.59, 95% CI 1.09-2.32), HF hospitalization (HR 1.33, 95% CI 1.09-1.61), all-cause mortality and/or HF hospitalization (HR 1.22, 95% CI 1.01-1.47), as well as cardiovascular mortality and/or HF hospitalization (HR 1.21, 95% CI 1.07-1.37). CONCLUSIONS: Prediabetes is associated with a worse prognosis in patients with HF. Further risk stratification and effective treatment strategies are needed in patients with prediabetes and with HF to improve the prognosis.

Comparative Genomics of Three Novel Jumbo Bacteriophages Infecting Staphylococcus aureus.

The majority of previously described Staphylococcus aureus bacteriophages belong to three major groups, namely, P68-like podophages, Twort-like or K-like myophages, and a more diverse group of temperate siphophages. Here, we present the following three novel S. aureus "jumbo" phages: MarsHill, Madawaska, and Machias. These phages were isolated from swine production environments in the United States and represent a novel clade of S. aureus myophage. The average genome size for these phages is ∼269 kb with each genome encoding ∼263 predicted protein-coding genes. Phage genome organization and content are similar to those of known jumbo phages of Bacillus sp., including AR9 and vB_BpuM-BpSp. All three phages possess genes encoding complete virion and nonvirion RNA polymerases, multiple homing endonucleases, and a retron-like reverse transcriptase. Like AR9, all of these phages are presumed to have uracil-substituted DNA which interferes with DNA sequencing. These phages are also able to transduce host plasmids, which is significant as these phages were found circulating in swine production environments and can also infect human S. aureus isolates. IMPORTANCE This study describes the comparative genomics of the following three novel S. aureus jumbo phages: MarsHill, Madawaska, and Machias. These three S. aureus myophages represent an emerging class of S. aureus phage. These genomes contain abundant introns which show a pattern consistent with repeated acquisition rather than vertical inheritance, suggesting intron acquisition and loss are active processes in the evolution of these phages. These phages have presumably hypermodified DNA which inhibits sequencing by several different common platforms. Therefore, these phages also represent potential genomic diversity that has been missed due to the limitations of standard sequencing techniques. In particular, such hypermodified genomes may be missed by metagenomic studies due to their resistance to standard sequencing techniques. Phage MarsHill was found to be able to transduce host DNA at levels comparable to that found for other transducing S. aureus phages, making it a potential vector for horizontal gene transfer in the environment.

Prediabetes and the risk of heart failure: A meta-analysis.

AIM: To determine the role of prediabetes in the incidence of heart failure (HF). MATERIALS AND METHODS: We searched electronic databases (PubMed, Embase, Google Scholar and OpenGrey) for studies up to 31 December 2020. Studies were included for meta-analysis if they reported adjusted relative risks (RRs) and 95% confidence intervals (CIs) for the risk of HF for prediabetes compared with normoglycaemia. Prediabetes was defined as impaired fasting glucose (IFG) according to the World Health Organization (WHO) criteria (IFG-WHO), or according to the American Diabetes Association (ADA) definition (IFG-ADA), impaired glucose tolerance (IGT), raised HbA1c according to the ADA criteria (HbA1c-ADA), or according to the International Expert Committee (IEC) recommendation (HbA1c-IEC). RESULTS: A total of 15 studies comprising 9,827,430 individuals provided data for this analysis. The median follow-up duration of the included studies was 8.0 years. Compared with normoglycaemia, prediabetes was associated with an increased risk for HF: IFG-ADA (RR: 1.09, 95% CI: 1.05-1.13), IFG-WHO (RR: 1.18, 95% CI: 1.07-1.30), IGT (RR 1.58, 95% CI 1.04-2.39), HbA1c-ADA (RR 1.28, 95% CI 1.16-1.41) or HbA1c-IEC (RR 1.40, 95% CI 1.09-1.79), respectively. CONCLUSIONS: Prediabetes is associated with an increased risk of HF. Future studies are needed to evaluate effective treatments for prediabetes to prevent the development and progression of HF.

Complete Genome Sequence of Burkholderia gladioli Phage Maja.

Burkholderia gladioli is a Gram-negative bacterium associated with cystic fibrosis infections. Here, we describe the genome sequence of B. gladioli phage Maja. Maja is most related to another Burkholderia phage, BcepF1, and may be a temperate phage, despite the absence of repressor or integrase homologs in its genome sequence.

α-Linolenic Acid and Risk of Heart Failure: A Meta-Analysis.

Background: The α-linolenic acid is a plant origin n-3 fatty acid that may reduce the risk of cardiovascular disease. However, the effect of α-linolenic acid (ALA) on the risk of heart failure (HF) remains unclear. In this meta-analysis, we aimed to determine the role of ALA in the risk of incident HF. Methods: Electronic databases were searched for studies up to August 10, 2021. Studies were included for meta-analysis if the adjusted risk of HF in different dietary intake or circulating levels of ALA was reported. We used the random-effects model to calculate the estimated hazard ratios (HRs) and 95% CI for higher ALA. Results: A total of 6 studies (7 cohorts) comprising 135,270 participants were included for meta-analysis. After a median follow-up duration of 10 years, 5,905 cases of HF were recorded. No significant heterogeneity was observed among all the included studies. Random-effects model analyses showed that there was no significant association between ALA and the risk of incident HF, either assessed as quintiles (highest quintile vs. lowest quintile: HR = 0.95, 95% CI = 0.86-1.06) or per 1 SD increment (HR = 0.99, 95% CI = 0.95-1.01). Furthermore, we did not observe any association between ALA and the risk of HF in subgroup analyses performed according to age, sex, follow-up duration, and measuring method of ALA. Conclusions: We found no association between ALA and the risk of incident HF, suggesting that ALA might not be effective in the prevention of HF.

Pooled analysis of the Xpert MTB/RIF assay for diagnosing tuberculous meningitis.

BACKGROUND: Tuberculous meningitis (TBM) is one of the most serious types of extrapulmonary tuberculosis. However, low sensitivity of culture of cerebrospinal fluid (CSF) increases the difficulty in clinical diagnosis, leading to diagnostic delay, and misdiagnosis. Xpert MTB/RIF assay is a rapid and simple method to detect tuberculosis. However, the efficacy of this technique in diagnosing TBM remains unclear. Therefore, a meta-analysis was conducted to evaluate the diagnostic efficacy of Xpert MTB/RIF for TBM, which may enhance the development of early diagnosis of TBM. METHODS: Relevant studies in the PubMed, Embase, and Web of Science databases were retrieved using the keywords 'Xpert MTB/RIF', 'tuberculous meningitis (TBM)'. The pooled sensitivity, pooled specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, summary receiver operator characteristic curve, and area under the curve (AUC) of Xpert MTB/RIF were determined and analyzed. RESULTS: A total of 162 studies were enrolled and only 14 met the criteria for meta-analysis. The overall pooled sensitivity of Xpert MTB/RIF was 63% [95% confidence interval (CI), 59-66%], while the overall pooled specificity was 98.1% (95% CI, 97.5-98.5%). The pooled values of positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 20.91% (12.71-52.82%), 0.40% (0.32-0.50%), and 71.49% (32.64-156.56%), respectively. The AUC was 0.76. CONCLUSIONS: Xpert MTB/RIF exhibited high specificity in diagnosing TBM in CSF samples, but its sensitivity was relatively low. It is necessary to combine other high-sensitive detection methods for the early diagnosis of TBM. Moreover, the centrifugation of CSF samples was found to be beneficial in improving the sensitivity.

Emergence of plasmid-mediated high-level tigecycline resistance genes in animals and humans.

Tigecycline is a last-resort antibiotic that is used to treat severe infections caused by extensively drug-resistant bacteria. tet(X) has been shown to encode a flavin-dependent monooxygenase that modifies tigecycline1,2. Here, we report two unique mobile tigecycline-resistance genes, tet(X3) and tet(X4), in numerous Enterobacteriaceae and Acinetobacter that were isolated from animals, meat for consumption and humans. Tet(X3) and Tet(X4) inactivate all tetracyclines, including tigecycline and the newly FDA-approved eravacycline and omadacycline. Both tet(X3) and tet(X4) increase (by 64-128-fold) the tigecycline minimal inhibitory concentration values for Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii. In addition, both Tet(X3) (A. baumannii) and Tet(X4) (E. coli) significantly compromise tigecycline in in vivo infection models. Both tet(X3) and tet(X4) are adjacent to insertion sequence ISVsa3 on their respective conjugative plasmids and confer a mild fitness cost (relative fitness of >0.704). Database mining and retrospective screening analyses confirm that tet(X3) and tet(X4) are globally present in clinical bacteria-even in the same bacteria as blaNDM-1, resulting in resistance to both tigecycline and carbapenems. Our findings suggest that both the surveillance of tet(X) variants in clinical and animal sectors and the use of tetracyclines in food production require urgent global attention.

Insights Into the Bovine Milk Microbiota in Dairy Farms With Different Incidence Rates of Subclinical Mastitis.

Bovine mastitis continues to be a complex disease associated with significant economic loss in dairy industries worldwide. The incidence rate of subclinical mastitis (IRSCM) can show substantial variation among different farms; however, the milk microbiota, which have a direct influence on bovine mammary gland health, have never been associated with the IRSCM. Here, we aimed to use high-throughput DNA sequencing to describe the milk microbiota from two dairy farms with different IRSCMs and to identify the predominant mastitis pathogens along with commensal or potential beneficial bacteria. Our study showed that Klebsiella, Escherichia-Shigella, and Streptococcus were the mastitis-causing pathogens in farm A (with a lower IRSCM), while Streptococcus and Corynebacterium were the mastitis-causing pathogens in farm B (with a higher IRSCM). The relative abundance of all pathogens in farm B (22.12%) was higher than that in farm A (9.82%). However, the genus Bacillus was more prevalent in farm A. These results may be helpful for explaining the lower IRSCM in farm A. Additionally, the gut-associated genera Prevotella, Ruminococcus, Bacteroides, Rikenella, and Alistipes were prevalent in all milk samples, suggesting gut bacteria can be one of the predominant microbial contamination in milk. Moreover, Listeria monocytogenes (a foodborne pathogen) was found to be prevalent in farm A, even though it had a lower IRSCM. Overall, our study showed complex diversity between the milk microbiota in dairy farms with different IRSCMs. This suggests that variation in IRSCMs may not only be determined by the heterogeneity and prevalence of mastitis-causing pathogens but also be associated with potential beneficial bacteria. In the future, milk microbiota should be considered in bovine mammary gland health management. This would be helpful for both the establishment of a targeted mastitis control system and the control of the safety and quality of dairy products.

Corrigendum: Staphylococcus aureus Bacteriophage Suppresses LPS-Induced Inflammation in MAC-T Bovine Mammary Epithelial Cells.

[This corrects the article DOI: 10.3389/fmicb.2018.01614.].

Alterations in the diversity and composition of mice gut microbiota by lytic or temperate gut phage treatment.

Phages, the most abundant species in the mammalian gut, have numerous advantages as biocontrol agent over antibiotics. In this study, mice were orally treated with the lytic gut phage PA13076 (group B), the temperate phage BP96115 (group C), no phage (group A), or streptomycin (group D) over 31 days. At the end of the experiment, fecal microbiota diversity and composition was determined and compared using high-throughput sequencing of the V3-V4 hyper-variable region of the 16S rRNA gene and virus-like particles (VLPs) were quantified in feces. There was high diversity and richness of microbiota in the lytic and temperate gut phage-treated mice, with the lytic gut phage causing an increased alpha diversity based on the Chao1 index (p < 0.01). However, the streptomycin treatment reduced the microbiota diversity and richness (p = 0.0299). Both phage and streptomycin treatments reduced the abundance of Bacteroidetes at the phylum level (p < 0.01) and increased the abundance of the phylum Firmicutes. Interestingly, two beneficial genera, Lactobacillus and Bifidobacterium, were enhanced by treatment with the lytic and temperate gut phage. The abundance of the genus Escherichia/Shigella was higher in mice after temperate phage administration than in the control group (p < 0.01), but lower than in the streptomycin group. Moreover, streptomycin treatment increased the abundance of the genera Klebsiella and Escherichia/Shigella (p < 0.01). In terms of the gut virome, fecal VLPs did not change significantly after phage treatment. This study showed that lytic and temperate gut phage treatment modulated the composition and diversity of gut microbiota and the lytic gut phage promoted a beneficial gut ecosystem, while the temperate phage may promote conditions enabling diseases to occur.