Comparative in vitro activity of ceftaroline,ceftaroline-avibactam,and other antimicrobial agents against aerobic and anaerobic bacteria cultured from infected diabetic foot wounds

Foot infections are the most common infectious complication of diabetes. Moderate to severe diabetic foot infections (DFI) are typically polymicrobial with both aerobic and anaerobic organisms. The role of MRSA in these wounds has become an increasing concern. To determine if the addition of avibactam, a novel non-beta-lactam beta-lactamase inhibitor, to ceftaroline would be more active than ceftaroline alone, we tested 316 aerobic pathogens and 154 anaerobic recovered from patients with moderate to severe DFI, and compared ceftaroline with and without avibactam to other agents. Testing on aerobes was done by broth microdilution and by agar dilution for anaerobes, according to CLSI M11-A8, and M7-A8 standards. Ceftaroline-avibactam MIC₉₀ for all Staphylococcus spp. including MRSA was 0.5 μg/mL, and for enterococci was 1 μg/mL. The MIC₉₀s for enteric Gram-negative rods was 0.125 μg/mL. The addition of avibactam to ceftaroline reduced the ceftaroline MICs for 2 strains of resistant Enterobacter spp. and for 1 strain of Morganella. Against anaerobic Gram-positive cocci ceftaroline-avibactam had an MIC₉₀ 0.125 μg/mL and for clostridia 1 μg/mL. Avibactam improved ceftaroline’s MIC₉₀s for Bacteroides fragilis from >32 to 2 μg/mL and for Prevotella spp. from >32 to 1 μg/mL. Ceftaroline alone demonstrates excellent in vitro activity against most of the aerobes found in moderate to severe DFI. The addition of avibactam provides an increased spectrum of activity including the beta-lactamase producing Prevotella, Bacteroides fragilis and ceftaroline resistant gram-negative enteric organisms.     

Sequential Changes in Luminal Microflora and Mucosal Cytokine Expression during Developing of Colitis in HLA-B27/β 2 -Microglobulin Transgenic Rats

Background: Transgenic rats expressing HLA-B27 and human β 2 -microglobulin (HLA-B27 rats) spontaneously develop chronic colitis resembling human inflammatory bowel disease. We investigated the sequential changes in the luminal bacterial flora and mucosal cytokine mRNA expression in this model. Methods: HLA-B27 rats were maintained in a specific pathogen-free environment, and luminal microflora was evaluated by standard bacterial culture technique. The expression of mucosal cytokine mRNA was analysed by RT-PCR methods. Results: Clinical symptoms of colitis appeared at 8 weeks of age. The total number of obligate anaerobes was higher than those of facultative anaerobes during the experimental period. At 6 weeks of age, the colonization of Bacteroides spp., Bifidobacterium spp. and Lactobacillus spp. was already detectable at high concentrations, whereas Clostridium spp. and Eubacterium spp. were not detected. The expression of proinflammatory cytokines (IL-1 β , IL-8 and TNF- α ) appeared at 8 weeks of age, and these were detectable until 17 weeks. A similar pattern was observed in the expression of Th1 cytokines (IL-2, IL-12 and IFN- &#110 ). On the other hand, the expression of Th2 cytokines (IL-4, IL-10 and TGF- β ) was weak. IL-4 mRNA expression was weakly detectable only at 6 and 8 weeks of age. The expression of IL-10 and TGF- β mRNA was scarcely detectable throughout the experimental period. Conclusion: The development of colitis may be mediated by both the predominant expression of Th1 cytokines and the weakness of Th2 cytokine expression in the mucosa. The colonization of anaerobic bacteria, especially Bacteroides spp., may be initiating and promoting these cytokine responses.     

Bacteroides forsythus ATCC43037菌体蛋白与人类唾液酸性富脯蛋白的相互作用

目的：探讨福赛类杆菌与人类唾液富脯蛋白相互作用的蛋白分子。方法：Western—blot方法。将人工合成唾液富脯蛋白用生物素标记，福赛类杆菌全菌蛋白凝胶电泳，半干转移至纤维膜上，观察二者的相互作用。结果：富脯蛋白能与分子量为85KD、65KD、60KD、以及49KD的福赛类杆菌蛋白发生结合。结论：福赛类杆菌存在与人类唾液富脯蛋白相互结合的粘附素。     

Comparative mitogenicity and polyclonal B cell activation capacity of eight oral or nonoral bacterial lipopolysaccharides in cultures of spleen cells from athymic (nu/nu-BALB/c) and thymic (BALB/c) mice

Optimal stimulatory doses of purified phenol-water extracted lipopolysaccharides (LPS) from 5 selected strains of 3 putative periodontopathogens (Fusobacterium nucleatum, Prevotella intermedia, and Veillonella), 3 strains of 2 nonoral bacterial species (Bacteroides fragilis and Salmonella enteritidis), and pokeweed mitogen (PWM) induced significantly higher maximum mitogenic responses and polyclonal Ig production in cultures of unfractionated spleen cells from nu/nu-BALB/c (nude) than from BALB/c (normal) mice. Compared with PWM, the LPS were stronger mitogens showing relative mitogenic capacities: B. fragilis LPS greater than F. nucleatum LPS greater than S. enteritidis LPS, Veillonella LPS, and P. intermedia LPS. B. fragilis LPS was the most and S. enteritidis LPS the least effective polyclonal B cell activator of total Ig, IgG2a, IgG2b, IgG3, IgA, and IgM secretion. IgG1 was not detected. P. intermedia LPS was the strongest IgA inducer. Kinetic observations indicated mitogenic responses and polyclonal B cell activation in a close sequential order in nude and normal cells. The LPS were potent Ag- and T cell-independent polyclonal B cell activators and LPS of subgingival plaque bacteria may therefore play a nonspecific role in the pathogenesis of periodontal diseases.     

Molecular genetic detection of Bacteroides heparinolyticus in adult periodontitis

Bacteroides heparinolyticus in subgingival plaque was identified using a digoxigen-in-labeled whole genomic DNA probe and a polymerase chain reaction (PCR) assay based on 16S rRNA species-specific primers (5'-ATG GTG ATT CCG CAT GGT TTC TCC-3'(base position, 188-212) and 5'-CAA ACT TTC ACA GCT GAC TTA AGC-3'(592-615)). Subgingival specimens obtained by paper points from 3 deep periodontal pockets in each of 113 adults were examined. The DNA probe reacted with all pure isolates tested of B. heparinolyticus and did not react with other oral species tested; the probe showed positive reactions in 74.3% of the patient samples examined. The PCR primers produced the 428 bp species specific amplification product in all B. heparinolyticus test strains and did not reveal detectable amplicons with strains of other subgingival species. The PCR method detected 50 B. heparinolyticus cells dispersed in subgingival plaque. PCR only revealed B. heparinolyticus in 6.2% of the patient samples studied. The higher level of positive specimens with the DNA probe was probably due to false-positive reactions from cross-hybridization with unknown subgingival species. This study suggests that the PCR method amplifying specific 16S rRNA sequences represents an easy and valuable means to detect B. heparinolyticus in subgingival plaque. The low prevalence of subgingival B. heparinolyticus does not incriminate the organism in the etiology of adult periodontitis.     

Bacterqides ureolyticus in men consulting for infertility

Summary: A screening of 3196 semen analyses performed in our clinic from January 1986 to December 1990 revealed 314 (9.8%) patients whose semen was infected with Bacteroides ureolyticus . Investigating the relationship between the presence of B. ureolyticus , the seminal microflora and the conventional semen parameters, we observed that the presence of this micro-organism in the semen was coupled (1) to an increased presence of Enterococcus species, (2) to an increased number of short-tailed spermatozoa and epithelial cells, and (3) to a decreased total fructose concentration (mg ejaculate⁻¹). These results suggest that B. ureolyticus or its toxins may influence sperm morphology and function by yet unknown mechanisms and may also increase the number of epithelial cells by soft tissue infection in vivo . The decreased fructose levels suggest that this anaerobic micro-organism might specifically colonize the seminal vesicles, while the normal zinc values recorded suggest a normal prostatic function. Overall, our data support the hypothesis that the presence of B. ureolyticus is not associated with nongonococcal urethritis.     

脆弱类杆菌多糖复合物抗原的提取及其鉴定

经酸、ＥＤＴＡ、脱氧胆酸钠和加热处理后从脆弱类杆菌ＡＴＣＣ２５２８５和ＣＤＣ１４４６２提取到两种多糖复合物。每种复合物中糖类与蛋白质的比例接近１：１，两种复合物之间糖类和蛋白质的相对含量世接近，提示有共同的基本结构。三类糖基可能由荚膜多糖和脂多糖成分组成。免疫血清学鉴定的结果表明两种多糖复合物都是本菌特异的表面抗原决定簇。提示可建立更特异免疫学方法诊断本菌感染。     

Features of gut microbiota in patients with anorexia nervosa

Background:Anorexia nervosa (AN) is a psychological disorder, which is characterized by the misunderstanding of body image, food restriction, and low body weight. An increasing number of studies have reported that the pathophysiological mechanism of AN might be associated with the dysbiosis of gut microbiota. The purpose of our study was to explore the features of gut microbiota in patients with AN, hoping to provide valuable information on its pathogenesis and treatment.Methods:In this cross-sectional study, from August 2020 to June 2021, patients with AN who were admitted into Peking University Third Hospital and Peking University Sixth Hospital (n = 30) were recruited as the AN group, and healthy controls (HC) were recruited from a middle school and a university in Beijing (n = 30). Demographic data, Hamilton Depression Scale (HAMD) scores of the two groups, and length of stay of the AN group were recorded. Microbial diversity analysis of gut microbiota in stool samples from the two groups was analyzed by 16S ribosomal RNA (rRNA) gene sequencing.Results:The weight (AN vs. HC, [39.31 ± 7.90] kg vs. [56.47 ± 8.88] kg, P < 0.001) and body mass index (BMI, AN vs. HC, [14.92 ± 2.54] kg/m²vs. [20.89 ± 2.14] kg/m², P < 0.001) of patients with AN were statistically significantly lower than those of HC, and HAMD scores in AN group were statistically significantly higher than those of HC. For alpha diversity, there were no statistically significant differences between the two groups; for beta diversity, the two groups differed obviously regarding community composition. Compared to HC, the proportion of Lachnospiraceae in patients with AN was statistically significantly higher (AN vs. HC, 40.50% vs. 31.21%, Z = −1.981, P = 0.048), while that of Ruminococcaceae was lower (AN vs. HC, 12.17% vs. 19.15%, Z = −2.728, P = 0.007); the proportion of Faecalibacterium (AN vs. HC, 3.97% vs. 9.40%, Z = −3.638, P < 0.001) and Subdoligranulum (AN vs. HC, 4.60% vs. 7.02%, Z = −2.369, P = 0.018) were statistically significantly lower, while that of Eubacterium_hallii_group was significantly higher (AN vs. HC, 7.63% vs. 3.43%, Z = −2.115, P = 0.035). Linear discriminant effect (LEfSe) analysis (LDA score >3.5) showed that o_Lachnospirales, f_Lachnospiraceae, and g_Eubacterium_hallii_group (o, f and g represents order, family and genus respectively) were enriched in patients with AN. Microbial function of nutrient transport and metabolism in AN group were more abundant (P > 0.05). In AN group, weight and BMI were significantly negatively correlated with the abundance of Bacteroidota and Bacteroides, while positively correlated with Subdoligranulum. BMI was significantly positively correlated with Firmicutes; HAMD scores were significantly negatively correlated with Faecalibacterium.Conclusions:The composition of gut microbiota in patients with AN was different from that of healthy people. Clinical indicators have correlations with the abundance of gut microbiota in patients with AN.     

Fibronectin fragmentation induced by dental plaque and Bacteroides gingivalis

Abstract – Degradation of fibronectin (FN) by subgingival and supragingival plaque and Bacteroides gingivalis (Bg) was studied in vitro. The degradation of FN by both types of plaque was relatively rapid, continuous but incomplete. Some differences were found between supra-and subgingival samples. Supragingival plaque extracts produced several FN fragments of 110–180 kd during short incubations, of 15–60 min. The predominant fragment after overnight incubation was a 110 kd polypeptide. With subgingival plaque extract a more extensive degradation of FN was noted. The main degradation product was a 120 kd fragment after overnight incubation. Several peptide fragments were released from fibronectin by Bg extracts. Their molecular size was different from those produced by trypsin, elastase or dental plaque. When cell extracts of Bg were fractionated by high performance liquid chromatography, three separate peaks of fibronectin degrading activity were obtained. Two of those peaks also contained trypsin-like enzyme activity. The degradation of fibronectin and the subsequent formation of biologically active peptides may have many effects in periodontal pockets. These may include modifying effects on plaque growth and wound healing.     

Transfer of plasmid pE5-2 from Escherichia coli to Bacteroides gingivalis and B. intermedius

A unique shuttle plasmid, pE5-2, previously constructed to mediate gene transfer from Escherichia coli to colonic Bacteroides spp. has also been transferred via conjugation from E. coli to isolates of Bacteroides gingivalis and B. intermedius. The transfer occurred at a frequency of 1.4 to 2 x 10(-7) per recipient. The presence of the plasmid in transconjugants was verified by hybridization of the total DNA of B. gingivalis recipients with sequences of the pE5-2 plasmid, as well as by standard plasmid isolation techniques.