Molecular epidemiology and characterization of antimicrobial-resistant Staphylococcus haemolyticus strains isolated from dairy cattle milk in Northwest, China.

Introduction: Non-aureus Staphylococcus (NAS) species are currently the most commonly identified microbial agents causing sub-clinical infections of the udder and are also deemed as opportunistic pathogens of clinical mastitis in dairy cattle. More than 10 NAS species have been identified and studied but little is known about S. haemolyticus in accordance with dairy mastitis. The present study focused on the molecular epidemiology and genotypic characterization of S. haemolyticus isolated from dairy cattle milk in Northwest, China. Methods: In this study, a total of 356 milk samples were collected from large dairy farms in three provinces in Northwest, China. The bacterial isolation and presumptive identification were done by microbiological and biochemical methods following the molecular confirmation by 16S rRNA gene sequencing. The antimicrobial susceptibility testing (AST) was done by Kirby-Bauer disk diffusion assay and antibiotic-resistance genes (ARGs) were identified by PCR. The phylogenetic grouping and sequence typing was done by Pulsed Field Gel Electrophoresis (PFGE) and Multi-Locus Sequence Typing (MLST) respectively. Results: In total, 39/356 (11.0%) were identified as positive for S. haemolyticus. The overall prevalence of other Staphylococcus species was noted to be 39.6% (141/356), while the species distribution was as follows: S. aureus 14.9%, S. sciuri 10.4%, S. saprophyticus 7.6%, S. chromogenes 4.2%, S. simulans 1.4%, and S. epidermidis 1.1%. The antimicrobial susceptibility of 39 S. haemolyticus strains exhibited higher resistance to erythromycin (92.3%) followed by trimethoprim-sulfamethoxazole (51.3%), ciprofloxacin (43.6%), florfenicol (30.8%), cefoxitin (28.2%), and gentamicin (23.1%). All of the S. haemolyticus strains were susceptible to tetracycline, vancomycin, and linezolid. The overall percentage of multi-drug resistant (MDR) S. haemolyticus strains was noted to be 46.15% (18/39). Among ARGs, mphC was identified as predominant (82.05%), followed by ermB (33.33%), floR (30.77%), gyrA (30.77%), sul1 (28.21%), ermA (23.08%), aadD (12.82%), grlA (12.82%), aacA-aphD (10.26%), sul2 (10.26%), dfrA (7.69%), and dfrG (5.13%). The PFGE categorized 39 S. haemolyticus strains into A-H phylogenetic groups while the MLST categorized strains into eight STs with ST8 being the most predominant while other STs identified were ST3, ST11, ST22, ST32, ST19, ST16, and ST7. Conclusion: These findings provided new insights into our understanding of the epidemiology and genetic characteristics of S. haemolyticus in dairy farms to inform interventions limiting the spread of AMR in dairy production.

Effects of different composting methods on antibiotic-resistant bacteria, antibiotic resistance genes, and microbial diversity in dairy cattle manures.

Composting is a common practice used for treating animal manures before they are used as organic fertilizers for crop production. Whether composting can effectively reduce microbial pathogens and antibiotic resistance genes remain poorly understood. In this study, we compared 3 different dairy manure composting methods-anaerobic fermentation (AF), static compost (SC), and organic fertilizer production (OFP)-for their effects on antibiotic-resistant bacteria, antibiotic resistance genes, and microbial community diversity in the treated manures. The 3 composting methods produced variable and distinct effects on antibiotic-resistant bacteria, zoonotic bacteria, and resistance genes, some of which were decreased and others of which showed no significant changes during composting. Particularly, SC and OFP reduced chloramphenicol resistance gene fexA and opportunistic pathogen Vibrio fluvialis, whereas AF significantly reduced tetracycline resistance gene tetB and opportunistic pathogens Enterococcus faecium and Escherichia fergusonii. The compositions of microbial communities varied significantly during the composting processes, and there were significant differences between the 3 composting methods. In all 3 composts, the dominant phyla were Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. Interestingly, Firmicutes, Proteobacteria, and Bacteroidetes remained stable in the entire AF process, whereas they were dominated at the beginning, decreased at the early stage of composting, and rebounded at the later stage during SC and OFP. In general, SC and OFP produced a more profound effect than AF on microbial community diversities, pathogens, and dominant species. Additionally, Enterococcus aquimarinus was isolated from AF for the first time. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States function prediction analysis indicated that the genes related to membrane transport and amino acid metabolism were abundant in the 3 composts. The metabolism of amino acids, lipids, and carbohydrates increased as composting progressed. The biosynthesis of antibiotics was enhanced after fermentation in the 3 composting methods, and the increase in the SC was the most obvious. These results reveal dynamic changes in antibiotic-resistant bacteria, antibiotic resistance genes, microbial community composition, and function succession in different dairy manure composts and provide useful information for further optimization of composting practices.

Effects of CRRT on renal function and toxin clearance in patients with sepsis: a case-control study.

OBJECTIVE: To explore the effects of continuous renal replacement therapy (CRRT) on renal function and toxin clearance in patients with sepsis and concurrent acute kidney injury (AKI). METHOD: A retrospective analysis was performed using the medical records of 115 patients with sepsis and AKI. Among them, 60 patients received routine treatment (group A) and 55 patients received CRRT plus routine treatment (group B). RESULT: After treatment, the clearance rates of serum creatinine, lactic acid, and urea nitrogen were significantly lower in group A than in group B. The decrease in high-sensitivity C-reactive protein and tumor necrosis factor-α levels after treatment was significantly higher in group B than in group A. For the Acute Physiology Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores from the two groups, the scores were significantly lower in group B than in group A. The mortality rate within 28 days was significantly higher in group A than in group B. CONCLUSION: CRRT can effectively improve the condition of patients with sepsis and AKI, promote elimination of toxins (serum creatinine, lactic acid, and urea nitrogen) from the body, and reduce the mortality rate.

Effect of VTILVOT variation rate on the assessment of fluid responsiveness in septic shock patients.

This study aimed to assess the predictive value of velocity time integral (VTI) of the left ventricular outflow tract (LVOT) on volume expansion test (VET) as an indicator of volume responsiveness in septic shock patients. Septic shock patients undergoing mechanical ventilation were recruited. The hemodynamic parameters before and after VE were monitored by pulse indicated continuous cardiac output (PiCCO) and echocardiography. Heart rate, cardiac index (CI), mean arterial pressure (MAP), central venous pressure, stroke volume variation (SVV), CI and variation of pulse pressure (PPV), and the changes in cardiac parameters (Dheart rate, Dmean arterial pressure, Dcentral venous pressure, DSVV, DCI, and DPPV) were determined. The relationships of hemodynamic parameters and their changes with DVTI were further evaluated with Pearson relation analysis. The value of these parameters in fluid responsiveness prediction was evaluated by using the receiver operating characteristic (ROC) curve analysis. Results showed that 44 VETs were performed in 44 septic shock patients with responsiveness in 24 patients and non-responsiveness in 20. The CI increased by ≥ 15% in responsive patients, but by<15% in non-responsive patients after VET. There were significant differences in the SVV and PPV after VET between responsive and non-responsive groups. DSVV, DPPV, and DCI were positively related to DVTI. The area under ROC curve (AUC) for SVV in fluid responsiveness prediction was 0.80, and the sensitivity and specificity of SVV were 66.5% and 95%, respectively, when the cut-off value was 24.8%. The AUC for PPV in fluid responsiveness prediction was 0.843, and the sensitivity and specificity of PPV were 83.3% and 75%, respectively, when the cut-off value was 25.8%. The AUC for DVTILVOT in fluid responsiveness prediction was 0.956, and the sensitivity and specificity were 87.5% and 95%, respectively, when the cut-off value was 15.9%. In conclusion, DVTILVOT is effective to predict fluid responsiveness after VET in mechanical ventilation patients with septic shock. It may serve as a new, noninvasive and functional hemodynamic parameter with the same accuracy to SVV.

Clinical efficacy and safety of somatostatin in the treatment of early postoperative inflammatory small bowel obstruction: A protocol for systematic review and meta analysis.

BACKGROUND: As one of the complications after abdominal operation, early postoperative inflammatory small bowel obstruction (EPISBO) is a great trouble for many patients. The use of somatostatin in treating this disease had been widely reported, but its efficacy and safety were controversial. Therefore, the present research carried out a systematic review of the clinical efficacy and safety of somatostatin in treating EPISBO. METHODS: Computer retrieval was conducted in foreign databases (including PubMed, The Cochrane Library, and Embase) and Chinese database (including Sino Med, CNKI, VIP, and WangFang Data), supplementary search for the literatures included was performed, and manual retrieval was performed in abstracts, books, and non-electronic magazines related to the present research to ensure the recall rate. Among all republished relevant experimental studies in Chinese and English from January 1, 1996 to February 1, 2020, randomized controlled trials on the curative efficacy of somatostatin for EPISBO were collected. The evaluation measures included patients' total effective rate, peristaltic sound recovery time, time of disappearance of abdominal pain, time of first defecation after operation, drainage of gastrointestinal decompression and length of stay after treatment. The literatures were selected by two investigators independently to extract data according to the inclusion and exclusion criteria, Bias Risk Assessment Tool recommended by Cochrane Review Hand book 5.2 was used to assess literature quality, and meta-analysis was carried out by using soft Stata 12.0. RESULTS: This study will scientifically and effectively analyze the clinical efficacy and safety of somatostatin in the treatment of EPISBO through systematic review and meta-analysis. ETHICS AND DISSEMINATION: The results of this study will be published in a peer-reviewed SCI journal to provide evidence-based medical evidence for the clinical treatment of early postoperative inflammatory bowel obstruction. PROTOCOL AND REGISTRATION: Open Science Framework (https://osf.io, OSF), registration number: ryd2g.