Treatment of psoriasis vulgaris using Bacteroides fragilis BF839: a single-arm, open preliminary clinical study / 生物工程学报

Psoriasis is considered as an inflammatory disease driven by T cells, and its pathogenesis is closely related to the imbalance of intestinal bacteria flora. It has been reported that Bacteroides fragilis could play an anti-inflammatory role by regulating the expression of cytokines in T cells. To date, there is no report using B. fragilis to treat psoriasis. In this study, we explored the therapeutic effect of B. fragilis BF839 on psoriasis. We selected 27 psoriasis patients who were treated in the Second Affiliated Hospital of Guangzhou Medical University from April to October 2019. The patients were given B. fragilis BF839 orally for 12 weeks while maintaining the original treatment. The psoriasis area and severity index (PASI) score was evaluated before and after the treatment. The rate of drug withdrawal and reduction after 12 weeks of treatment were calculated. Our results showed that the rate of 12-week trial completion was 96.3% (26/27). We used PASIN to define the proportion of people whose PASI score decreased more than or equal to N% after treatment. At 12 weeks, PASI30, PASI50, and PASI75 were 65.4%, 42.3%, and 19.2%, respectively. The PASI score was 9.1±5.9 and 5.8±4.9 before and after 12 weeks of treatment respectively, and the difference was statistically significant (P0.05). The adverse reaction rate of patients was 3.8% (1/26) within 12 weeks of treatment, including 1 case of constipation, and the rate of drug withdrawal and reduction was 60.0%. The above results suggest that B. fragilis BF839 may be functional on the treatment of psoriasis by reducing the PASI score and the drug usage rate with few side effect, which deserves further study.

Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Abstract Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Bacteroides Fragilis induces conformational alterations in Trichomonas Vaginalis ultrastructure in an in vitro interaction

Bacteroides genus are commonly found on mucous membranes, including the female genital tract, acting as agents for several site infections. Anaerobic infections are usually polymicrobial and endogenous. Trichomonas vaginalis, the trichomoniasis etiologic agent, is a facultative anaerobic flagellated parasite spread worldwide. The purpose of this study was to explore the association between vaginal bacteria and T. vaginalis, as well as to understand factors that may favour the infection of T. vaginalis. We have, therefore, used T. vaginalis trophozoites and the species Bacteroides fragilis, which is considered the most important in its genus, once it is the most commonly isolated bacteria from endogenous infections. The parasite-bacteria interaction was performed in different proportions in periods varying from 1 to 12 hours applying viability tests. The data were analyzed to compare the parasite viability in vitro in the presence and absence of B. fragilis. The results indicate that in the 1:100 proportion postinteraction analysis, ultrastructural alterations were noticeable after 6 hours. After 8 hours, T. vaginalis viability decreased, and after 12 hours of interaction no viable trophozoites were found. These data suggest that the parasite can deal with B. fragilis in short interaction periods. However, in longer interaction periods the trophozoites collapse, indicating that B. fragilis may produce toxic metabolites against T. vaginalis activity.

Recuperación de bacterias aerobias y anaerobias de pacientes con apendicitis aguda mediante botellas de hemocultivo / Recovery of aerobic and anaerobic bacteria from patients with acute appendicitis using blood culture bottles

Introducción. La apendicitis aguda es la primera causa de abdomen agudo; sin embargo, poco se conoce sobre las bacterias asociadas y su perfil de sensibilidad. Objetivo. Identificar y determinar el patrón de resistencia de las bacterias aerobias y anaerobias aisladas en cultivo de líquido periapendicular tomado de los pacientes con apendicitis aguda, y establecer la proporción de bacterias según la fase clínica. Materiales y métodos. Se llevó a cabo un estudio descriptivo y prospectivo en el Hospital Universitario de San José de Bogotá (Colombia), en pacientes mayores de 16 años sometidos a apendicectomía abierta. Se tomaron muestras de líquido periapendicular, las cuales se sembraron directamente en botellas de hemocultivos para aerobios y anaerobios. Resultados. Se incluyeron 154 pacientes. Del total de cultivos, el 87 % (n=134) fueron positivos: 77 % (n=118) para aerobios y 51 % (n=79) para anaerobios. La proporción de cultivos positivos fue inferior en los casos de apendicitis no complicada, en comparación con aquellos de apendicitis complicada (80 % (66/83) Vs. 95 % (67/71); p=0,003). Los microorganismos aislados con mayor frecuencia fueron: Escherichia coli (53 %) (n=84), Bacteroides sp. (25 %) (n=25), Propionibacterium acnes (21 %) (n=21), Staphylococci coagulasa negativo (17 %) (n=27), Enterococcus sp. (10 %) (n=15) y Fusobacterium sp. (11 %) (n=11). La sensibilidad de E. coli a la amplicilina sulbactam fue de 30 %. La sensibilidad de Bacteroides spp. a la clindamicina y la ampicilina sulbactam fue de 91 %. El 100 % de los anaerobios fueron sensibles a piperacilina tazobactam, ertapenem, meropenem y metronidazol. Conclusiones. Los cultivos intraoperatorios son pertinentes en la apendicitis para determinar el patrón epidemiológico local, y establecer los antibióticos profilácticos y terapéuticos para esta enfermedad. Su siembra directa en botellas de hemocultivo permite una gran recuperación de microorganismos.

Introduction: Acute appendicitis is the first cause of acute abdomen, however, there is a little information about the associated bacteria and its sensibility profile. Objetive: To identify and to determine the resistance pattern of aerobic and anaerobic bacteria isolated in periapendicular fluid cultures taken in patients with acute appendicitis and to establish the proportions of isolates according to the clinical phase. Materials and methods: A descriptive and prospective study was undertaken at the Hospital Universitario de San José (Bogotá, Colombia) of patients older than sixteen years of age, undergoing an open appendectomy. A sample of periappendiceal fluid was taken, which was deposited directly into aerobic and anaerobic blood culture bottles. Results: One hundred and fifty-four patients were included. The overall positivity of cultures was 87% (n=1344); 77% (n=118) for aerobes and 51% (n=79) for anaerobes. The proportion of positive cultures was lower in the uncomplicated appendicitis cases as compared to the complicated ones (80% (66/83) vs. 95%(67/71), p = 0.003). The microorganisms isolated most frequently were: Escherichia coli (53%) (n=84); Bacteroides spp. (25%) (n=25); Propionibacterium acnes (21%) (n=21); coagulase negative Staphylococci (17%) (n=27); Enterococcus spp. (11%) (n=15), and Fusobacterium spp. (11%) (n=11). The sensitivity of E.coli to ampicillin/sulbactam was 30%. The sensitivity of Bacteroides spp. to clindamycin and ampicillin/sulbactam was 91%. All anaerobe isolates were sensitive to piperacillin/tazobactam, ertapenem, meropenem and metronidazole. Conclusions: Intraoperative cultures in acute appendicits are relevant in order to determine the local epidemiological pattern and to establish prophylactic and therapeutic antibiotics for this pathology; direct inoculation in blood culture bottles allows a high recovery of microorganisms.

Inactivation of MarR gene homologs increases susceptibility to antimicrobials in Bacteroides fragilis

ABSTRACT Bacteroides fragilis is the strict anaerobic bacteria most commonly found in human infections, and has a high mortality rate. Among other virulence factors, the remarkable ability to acquire resistance to a variety of antimicrobial agents and to tolerate nanomolar concentrations of oxygen explains in part their success in causing infection and colonizing the mucosa. Much attention has been given to genes related to multiple drug resistance derived from plasmids, integrons or transposon, but such genes are also detected in chromosomal systems, like the mar (multiple antibiotic resistance) locus, that confer resistance to a range of drugs. Regulators like MarR, that control expression of the locus mar, also regulate resistance to organic solvents, disinfectants and oxygen reactive species are important players in these events. Strains derived from the parental strain 638R, with mutations in the genes hereby known as marRI (BF638R_3159) and marRII (BF638R_3706) were constructed by gene disruption using a suicide plasmid. Phenotypic response of the mutant strains to hydrogen peroxide, cell survival assay against exposure to oxygen, biofilm formation, resistance to bile salts and resistance to antibiotics was evaluated. The results showed that the mutant strains exhibit statistically significant differences in their response to oxygen stress, but no changes were observed in survival when exposed to bile salts. Biofilm formation was not affected by either gene disruption. Both mutant strains however, became more sensitive to multiple antimicrobial drugs tested. This indicates that as observed in other bacterial species, MarR are an important resistance mechanism in B. fragilis.

Identification of the alpha-enolase P46 in the extracellular membrane vesicles of Bacteroides fragilis

BACKGROUND Members of the Bacteroides fragilis group are the most important components of the normal human gut microbiome, but are also major opportunistic pathogens that are responsible for significant mortality, especially in the case of bacteraemia and other severe infections, such as intra-abdominal abscesses. Up to now, several virulence factors have been described that might explain the involvement of B. fragilis in these infections. The secretion of extracellular membrane vesicles (EMVs) has been proposed to play a role in pathogenesis and symbiosis in gram-negative bacteria, by releasing soluble proteins and other molecules. In B. fragilis, these vesicles are known to have haemagglutination and sialidosis activities, and also contain a capsular polysaccharide (PSA), although their involvement in virulence is still not clear. OBJECTIVE The aim of this study was to identify proteins in the EMV of the 638R B. fragilis strain by mass spectrometry, and also to assess for the presence of Bfp60, a surface plasminogen (Plg) activator, previously shown in B. fragilis to be responsible for the conversion of inactive Plg to active plasmin, which can also bind to laminin-1. METHODS B. fragilis was cultured in a minimum defined media and EMVs were obtained by differential centrifugation, ultracentrifugation, and filtration. The purified EMVs were observed by both transmission electron microscopy (TEM) and immunoelectron microscopy (IM). To identify EMV constituent proteins, EMVs were separated by 1D SDS-PAGE and proteomic analysis of proteins sized 35 kDa to approximately 65 kDa was performed using mass spectrometry (MALDI-TOF MS). FINDINGS TEM micrographs proved the presence of spherical vesicles and IM confirmed the presence of Bfp60 protein on their surface. Mass spectrometry identified 23 proteins with high confidence. One of the proteins from the B. fragilis EMVs was identified as an enolase P46 with a possible lyase activity. MAIN CONCLUSIONS Although the Bfp60 protein was not detected by proteomics, α-enolase P46 was found to be present in the EMVs of B. fragilis. The P46 protein has been previously described to be present in the outer membrane of B. fragilis as an iron-regulated protein.

Effects of various prophylactic procedures on titanium surfaces and biofilm formation

PURPOSE: The aim of this study was to evaluate the effects of various prophylactic treatments of titanium implants on bacterial biofilm formation, correlating surface modifications with the biofilms produced by Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and bacteria isolated from saliva. METHODS: Pure titanium disks were treated with various prophylactic procedures, and atomic force microscopy (AFM) was used to determine the degree to which surface roughness was modified. To evaluate antibiofilm activity, we used P. aeruginosa PAO1, S. aureus, and saliva-isolated Streptococcus spp., Bacteroides fragilis, and Staphylococcus epidermidis. RESULTS: AFM showed that the surface roughness increased after using the air-polishing device and ultrasonic scaler, while a significant reduction was observed after using a curette or polishing with Detartrine ZTM (DZ) abrasive paste. In addition, we only observed a significant (P < 0.01) reduction in biofilm formation on the DZ-treated implant surfaces. CONCLUSION: In this study, both AFM and antibiofilm analyses indicated that using DZ abrasive paste could be considered as the prophylactic procedure of choice for managing peri-implant lesions and for therapy-resistant cases of periodontitis.

Intestinal microbiota, chronic inflammation, and colorectal cancer

In addition to genetic and epigenetic factors, various environmental factors, including diet, play important roles in the development of colorectal cancer (CRC). Recently, there is increasing interest in the intestinal microbiota as an environmental risk factor for CRC, because diet also influences the composition of the intestinal microbiota. The human intestinal microbiota comprises about 100 trillion microbes. This microbiome thrives on undigested dietary residues in the intestinal lumen and produces various metabolites. It is well known that the dietary risk factors for CRC are mediated by dysbiosis of the intestinal microbiota and their metabolites. In this review, we describe the bacterial taxa associated with CRC, including Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, Escherichia coli, and butyrate-producing bacteria. We also discuss the host-diet interaction in colorectal carcinogenesis.

Impact of microbiota in colorectal carcinogenesis: lessons from experimental models

A role of gut microbiota in colorectal cancer (CRC) growth was first suggested in germ-free rats almost 50 years ago, and the existence of disease-associated bacteria (termed pathobionts) had becoming increasingly evident from experimental data of fecal transplantation, and microbial gavage or monoassociation. Altered bacterial compositions in fecal and mucosal specimens were observed in CRC patients compared to healthy subjects. Microbial fluctuations were found at various cancer stages; an increase of bacterial diversity was noted in the adenoma specimens, while a reduction of bacterial richness was documented in CRC samples. The bacterial species enriched in the human cancerous tissues included Escherichia coli, Fusobacterium nucleatum, and enterotoxigenic Bacteroides fragilis. The causal relationship of gut bacteria in tumorigenesis was established by introducing particular bacterial strains in in situ mouse CRC models. Detailed experimental protocols of bacterial gavage and the advantages and caveats of different experimental models are summarized in this review. The microbial genotoxins, enterotoxins, and virulence factors implicated in the mechanisms of bacteria-driven tumorigenesis are described. In conclusion, intestinal microbiota is involved in colon tumorigenesis. Bacteria-targeting intervention would be the next challenge for CRC.

Anaerobic Bacteremia: Impact of Inappropriate Therapy on Mortality

BACKGROUND: Investigation on incidence and mortality of anaerobic bacteremia (AB) is clinically relevant in spite of its infrequent occurrence and not often explored, which report varies according to period and institutions. Therefore, it is necessary to analyze the incidence and risk factors related to mortality and assess clinical outcomes of AB in current aspect. MATERIALS AND METHODS: Characteristics of AB patients and anaerobic bacteria from blood culture at a university hospital in 2012 were reviewed retrospectively. The correlation between risk factors and 28-day patient mortality was analyzed. RESULTS: A total of 70 non-duplicated anaerobic bacteria were isolated from blood of 70 bacteremia patients in 2012. The history of cardiovascular disease as host's risk factor was statistically significant (P = 0.0344) in univariate and multivariate analysis. Although the inappropriate therapy was not statistically significant in univariate and multivariate analysis, the survival rate of bacteremia was significantly worse in patients who had inappropriate therapy compared with those underwent appropriate therapy (hazard ratio, 5.4; 95% confidence interval, 1.7-6.9; P = 0.004). The most frequently isolated organism was Bacteroides fragilis (32 isolates, 46%), followed by Bacteroides thetaiotaomicron (10, 14%), and non-perfringens Clostridium (7, 10%). CONCLUSION: The incidence of AB in 2012 was 2.3% (number of AB patients per 100 positive blood culture patients) and the mortality rate in patients with clinically significant AB was 21.4%. In addition, AB was frequently noted in patients having malignancy and the survival rate of AB was significantly worse in patients who received inappropriate therapy compared with those underwent appropriate therapy.

Bacteroides nordii and Bacteroides salyersiae Isolated from Post-operative Peritonitis Patients

In this study, we report three cases in which two species of the Bacteroides fragilis group, 'Bacteroides nordii' and 'Bacteroides salyersiae', were isolated from peritoneal fluid cultures from post-operative peritonitis patients. The two species of the B. fragilis group were initially misidentified as B. fragilis/Bacteroides stercoris and Bacteroides ovatus by Rapid ID 32A (bioMérieux, France), and finally confirmed as B. nordii and B. salyersiae using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16s rRNA sequencing. For the identification of anaerobes, particularly B. fragilis group organisms, MALDI-TOF MS is a useful method not only because of its concordance with 16S rRNA sequencing results, but also because of its rapidity and simple procedure.

Enterotoxigenic and non-enterotoxigenic Bacteroides fragilis from fecal microbiota of children

Enterotoxigenic Bacteroides fragilis (ETBF) is an important part of the human and animal intestinal microbiota and is commonly associated with diarrhea. ETBF strains produce an enterotoxin encoded by the bft gene located in the B. fragilis pathogenicity island (BfPAI). Non-enterotoxigenic B. fragilis (NTBF) strains lack the BfPAI and usually show two different genetic patterns, II and III, based on the absence or presence of a BfPAI-flanking region, respectively. The incidence of ETBF and NTBF strains in fecal samples isolated from children without acute diarrhea or any other intestinal disorders was determined. All 84 fecal samples evaluated were B. fragilis-positive by PCR, four of them harbored the bft gene, 27 contained the NTBF pattern III DNA sequence, and 52 were considered to be NTBF pattern II samples. One sample was positive for both ETBF and NTBF pattern III DNA sequences. All 19 B. fragilis strains isolated by the culture method were bft-negative, 9 belonged to pattern III and 10 to pattern II. We present an updated overview of the ETBF and NTBF incidence in the fecal microbiota of children from Sao Paulo City, Brazil.

Evaluación farmacocinética/farmacodinámica (PK/PD) de un esquema de administración oral de metronidazol en intervalo ampliado para el manejo de infecciones producidas por Bacteroides fragilis / Pharmacokinetics/pharmacodinamic (PK/PD) evaluation of a short course of oral administration of metronidazole for the management of infections caused by Bacteroides fragilis

Introduction: Metronidazole is the antibiotic of choice for the management of infections caused by anaerobes. Its administration requires multiple daily doses causing increased medication errors. Due to its high post-antibiotic effect and rapid concentration-dependent bactericidal activity, administration of this antibiotic in an extended dosing interval would achieve PK/PD parameters effectively. Objective: To assess the probability of achieving effective PK/PD relationship with the administration of 1,000 mg every 24 hours of metronidazole for Bacteroides fragilis infections. Methods: A clinical trial was conducted in a group of volunteers who received a single oral dose of 500 or 1,000 mg of metronidazole. Determinations of values of Cmax, t max, and AUCC0-24 h. determined using the trapezoidal method, were obtained for a Markov simulation that would allow for determining the likelihood of achieving a AUC0-24 h/MIC ratio above 70 for infections caused by susceptible B. fragilis. Results: Cmax (24,03 ± 6,89 mg/L) and t max (1,20 ± 0.80 hrs) and the value of AUC0-24 h (241.91 ± 48.14 mg * h/L) were determined. The probability of obtaining a AUC0-24 h/MIC ratio greater than 70 was greater than 99%. Conclusion: From a pharmacokinetic perspective, with the administration of a daily dose of 1,000 mg of metronidazole, it is possible to achieve a therapeutic goal of AUC0-24 h/MIC ratio above 70 for the treatment of anaerobic infections.

Introducción: Metronidazol es el antimicrobiano de elección para el manejo de infecciones anaeróbicas. Su administración requiere de dosis múltiples provocando aumento en errores medicamentosos. Debido al efecto post-antibiótico y a la actividad bactericida concentración-dependiente, la administración de metronidazol en intervalos ampliados de administración permitiría alcanzar parámetros PK/PD efectivos. Objetivo: Evaluar la probabilidad de alcanzar una relación PK/PD efectiva con la administración de 1.000 mg cada 24 h de metronidazol para infecciones por Bacteroides fragilis. Método: Se realizó un ensayo clínico sobre un grupo de voluntarios a quienes se les administró una monodosis oral de 500 y 1.000 mg de metronidazol, respectivamente. Se establecieron parámetros farmacocinéticos empleando el método trapezoidal. Se realizó una simulación de Markov que permitiera establecer la probabilidad de alcanzar una relación AUC0-24 h/CIM > 70 en infecciones por B. fragilis. Resultados: Se determinaron los valores de Cmax (24,03 ± 6,89 mg/L), t max (1,20± 0,8h) y AUC0-24 h (241,91 ± 48,14 mg*h/L), con lo cual la probabilidad de alcanzar una relación AUC0-24 h/CIM > 70 con 1.000 mg de metronidazol fue superior a 99%. Conclusión: Con la administración de 1.000 mg cada 24 h sería posible alcanzar una relación PK/PD efectiva para el tratamiento de infecciones anaeróbicas.

Comparative Analysis of Gastrointestinal Microbiota Between Normal and Caudal-Related Homeobox 2 (Cdx2) Transgenic Mice

BACKGROUND/AIMS: Caudal-related homeobox 2 (Cdx2) is expressed in the human intestinal metaplastic mucosa and induces intestinal metaplastic mucosa in the Cdx2 transgenic mouse stomach. Atrophic gastritis and intestinal metaplasia commonly lead to gastric achlorhydria, which predisposes the stomach to bacterial overgrowth. In the present study, we determined the differences in gut microbiota between normal and Cdx2 transgenic mice, using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). METHODS: Twelve normal (control) and 12 Cdx2 transgenic mice were sacrificed, and the gastric, jejunal, ileac, cecal and colonic mucosa, and feces were collected. To quantitate bacterial microbiota, we used real-time qRTPCR with 16S rRNA gene-targeted, species-specific primers. RESULTS: The total numbers of bacteria in the gastric, jejunal, ileac, cecal, and colonic mucosa of the Cdx2 transgenic mice were significantly higher than those of the normal mice. The Bacteroides fragilis group and also Prevotella were not detected in the stomach of the normal mice, although they were detected in the Cdx2 transgenic mice. Moreover, the Clostridium coccoides group, Clostridium leptum subgroup, Bacteroides fragilis group, and Prevotella were not detected in the jejunum or ileum of the normal mice, although they were detected in the Cdx2 transgenic mice. The fecal microbiota of the normal mice was similar to that of the Cdx2 transgenic mice. CONCLUSIONS: Our results showed the differences in composition of gut microbiota between normal and Cdx2 transgenic mice, which may be caused by the development of gastric achlorhydria and intestinal metaplasia in Cdx2 transgenic mice.

The Growth Inhibition Effect on the Bacterial Vaginosis Causative Bacteria by Citric Acid and Trisodium Phosphate

Bacterial vaginosis (BV) is the most frequent vaginal disease being apt to relapse. The growth inhibition effect of the mixture of citric acid (CA) and trisodium phosphate (TSP) on BV causative bacteria and probiotics was measured. Gardnerella vaginalis was reduced to zero in WCCT-1 (CA 0.25% and TSP 0.55% in Wilkins-Chalgren broth), 2.0 x 10(4)/ml in WCCT-2 (CA 0.5% and TSP 0.8% in WC), and 3.3 x 10(3)/ml in WCCT-3 (CA 1.0% and TSP 2.6% in WC) comparing with 1.3 x 10(5)/ml in WC after 48 h. Bacteroides fragilis was reduced to 6.0 x 10(3)/ml in WCCA (CA 0.34% in WC), 2.3 x 10(2)/ml in WCCT (CA 0.5% and TSP 0.2% in WC), 7.0 x 10(3)/ml in WCHCl (HCl in WC) after 48 h. Mobiluncus mulieris was reduced to 1.08 x 10(4)/ml in WCCA, 1.03 x 10(3)/ml in WCCT, and 10 ea/ml in WCHCl after 48 h. Peptostreptococcus asaccharolyticus was completely inhibited in WCCA, WCCT, and WCHCl after 24 h. Probiotics, Steroidobacter denitrificans YH1 (3.4 x 10(7)/ml) and Lactobacillus crispatus YH2 (2.7 x 10(6)/ml), grew to 1.25 x 10(8)/ml and 2.6 x 10(7)/ml in MRSCA (CA 1.0% in MRS), 1.8 x 10(7)/ml and 4.6 x 10(6)/ml in MRSCT (CA 1.5% and TSP 0.58% in MRS), 1.2 x 10(8)/ml and 2.3 x 10(7)/ml in MRSHCl after 48 h, respectively. These results mean that the CA-TSP mixture can be used as the useful vaginal pH controller, growth inhibitor on BV causative bacteria, and an efficient means for settlement of probiotics.

Multicenter Study of Antimicrobial Susceptibility of Anaerobic Bacteria in Korea in 2012

BACKGROUND: Periodic monitoring of regional or institutional resistance trends of clinically important anaerobic bacteria is recommended, because the resistance of anaerobic pathogens to antimicrobial drugs and inappropriate therapy are associated with poor clinical outcomes. There has been no multicenter study of clinical anaerobic isolates in Korea. We aimed to determine the antimicrobial resistance patterns of clinically important anaerobes at multiple centers in Korea. METHODS: A total of 268 non-duplicated clinical isolates of anaerobic bacteria were collected from four large medical centers in Korea in 2012. Antimicrobial susceptibility was tested by the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin, piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, metronidazole, and tigecycline. RESULTS: Organisms of the Bacteroides fragilis group were highly susceptible to piperacillin-tazobactam, imipenem, and meropenem, as their resistance rates to these three antimicrobials were lower than 6%. For B. fragilis group isolates and anaerobic gram-positive cocci, the resistance rates to moxifloxacin were 12-25% and 11-13%, respectively. Among B. fragilis group organisms, the resistance rates to tigecycline were 16-17%. Two isolates of Finegoldia magna were non-susceptible to chloramphenicol (minimum inhibitory concentrations of 16-32 mg/L). Resistance patterns were different among the different hospitals. CONCLUSIONS: Piperacillin-tazobactam, cefoxitin, and carbapemems are highly active beta-lactam agents against most of the anaerobes. The resistance rates to moxifloxacin and tigecycline are slightly higher than those in the previous study.

Antimicrobial Susceptibility of Clinical Isolates of Bacteroides fragilis Group Organisms Recovered from 2009 to 2012 in a Korean Hospital

BACKGROUND: Periodic monitoring of antimicrobial resistance trends of clinically important anaerobic bacteria such as Bacteroides fragilis group organisms is required. We determined the antimicrobial susceptibilities of clinical isolates of B. fragilis group organisms recovered from 2009 to 2012 in a tertiary-care hospital in Korea. METHODS: A total of 180 nonduplicate clinical isolates of B. fragilis group organisms were collected in a tertiary care hospital. The species were identified by conventional methods: the ATB 32A rapid identification system (bioMerieux, France) and the Vitek MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (bioMerieux). Antimicrobial susceptibility was determined by the CLSI agar dilution method. RESULTS: Imipenem and meropenem resistance rates were 0-6% for B. fragilis group isolates. The rate of resistance to piperacillin-tazobactam was 2% for B. fragilis and 0% for other Bacteroides species, but 17% for B. thetaiotaomicron isolates. High resistance rates to piperacillin (72% and 69%), cefotetan (89% and 58%), and clindamycin (83% and 69%) were observed for B. thetaiotaomicron and other Bacteroides spp. The moxifloxacin resistance rate was 27% for other Bacteroides spp. The MIC50 and MIC90 of tigecycline were 2-4 microg/mL and 8-16 microg/mL, respectively. No isolates were resistant to chloramphenicol or metronidazole. CONCLUSIONS: Imipenem, meropenem, chloramphenicol, and metronidazole remain active against B. fragilis group isolates. Moxifloxacin and tigecycline resistance rates are 2-27% and 8-15% for B. fragilis group isolates, respectively.

Virulence factors and biofilm production by isolates of Bacteroides fragilis recovered from dog intestinal tracts

Bacteroides fragilis colonizes dog guts both as a commensal and as an opportunistic pathogen. This study aims to evaluate virulence factors of 13 B. fragilis strains isolated from dog intestinal tracts and their ability for biofilm formation. Capsules were detected in all the evaluated strains. A total of 61.5% of all strains were biofilm producers. These attributes most likely play an important role in B. fragilis persistent colonization in the gut.

Aislamientos bacterianos en apendicitis aguda / Bacterial isolations in acute appendicitis

La apendicitis aguda es una patología de interés a nivel mundial con una incidencia de 100 por cada 100.000 personas/año, reportada a nivel europeo y norteamericano. La fisiopatología en forma experimental se ha relacionado con un proceso obstructivo, que evoluciona a estado isquémico favoreciendo la translocación bacteriana, por lo cual se han relacionado los distintos microorganismos como factor de importancia en el desarrollo de sus complicaciones. Se realizó una revisión de los estudios publicados en PubMed en los últimos veinte años con términos MeSH appendicitis, bacteria y etiology donde se documento la E. coli comoel germen bacteriano más común y B. fragilis como un anaerobio frecuente. No se encontraron estudios que reporten perfiles de sensibilidad a resistencia antibiótica.

Acute appendicitis is a common clinical condition worldwide. Its current incidence is about 100 per 100,000 people-yearin Europe and North America. Experimentally, its pathophysiology has been related to an obstructive process which progresses to ischemia favoring bacterial translocation, due to which various microorganisms have been implicated asan important factor in the development of complications. A review of the studies published in PubMed during the last twenty years was performed using MeSH terms, appendicitis, bacteria and etiology. E. coli is documented in reviewed literature as the commonest bacteria isolated and B. fragilis as a frequent anaerobic organism. No studies reporting antibiotic sensitivity/ resistance profiles were found.

Primary Aortoenteric Fistula to the Sigmoid Colon in Association with Intra-abdominal Abscess / 대한소화기학회지

Primary aortoenteric fistula (PAEF) is a rare but catastrophic cause of massive gastrointestinal bleeding. Diagnosis of PAEF is difficult to make and is frequently delayed without strong clinical suspicion. Timely surgical intervention is essential for patient's survival. We report on a case of an 86-year-old woman with no history of abdominal surgery, who presented with abdominal pain. Initially, computed tomography scan showed an intra-abdominal abscess, located anterior to the aortic bifurcation. However, she was discharged without treatment because of spontaneous improvement on a follow-up computed tomography scan, which showed a newly developed right common iliac artery aneurysm. One week later, she was readmitted due to recurrent abdominal pain. On the second day of admission, sudden onset of gastrointestinal bleeding occurred for the first time. After several endoscopic examinations, an aortoenteric fistula bleeding site was found in the sigmoid colon, and aortography showed progression of a right common iliac artery aneurysm. We finally concluded that intra-abdominal abscess induced an infected aortic aneurysm and enteric fistula to the sigmoid colon. This case demonstrated an extremely rare type of PAEF to the sigmoid colon caused by an infected abdominal aortic aneurysm, which has rarely been reported.