Agglutination,Toxigenicity and Sorbitol Fermentation of Clostridium difficile

A total of 79 Clostridium difficile strains from different sources (50 strains from the fecal specimens of healthy adults, 13 from patients receiving antibiotics without gastrointestinal complications, 13 from antibiotic-associated pseudomembranous colitis (PMC) or diarrhea patients, and three strains from ATCC) were investigated for agglutinability, using formol-treated cells as antigen, in relation to toxigenicity. C. difficile strains tested were divided into four serovars, I, II, III, and IV, by the cross-agglutination test. The agglutinin absorption test revealed that strains of serovar I, agglutinable with high titers (5,120–10,240) to antiserum prepared against a highly toxigenic C. difficile strain, ATCC 17859, possessed the serovar-specific antigen. All of the strains of serovar I were highly toxigenic and all 13 strains isolated from the fecal specimens of antibiotic-associated PMC or diarrhea patients belonged to this serovar, whereas 19 (38%) out of 50 strains from healthy adults and four (30.8%) out of 13 strains from patients receiving antibiotics without gastrointestinal complications possessed this antigen. None of the strains of other clostridial species than C. difficile were agglutinated by the three reference antisera used. Further study on the sugar fermentation test disclosed that the sorbitol-fermenting property of C. difficile is very closely related to the toxigenicity and agglutinability.     

Clostridium difficile in emergency room

Clostridium difficile strains are known as etiological agents of pseudomembranous colitis (PMC), antibiotic-associated diarrhea (AAC) and colitis (AAC) and hospital-acquired infections. The aim of this study was to determine the frequency of C. difficile infection among patients in the emergency room and to compare isolated strains by phenotypic and genotypic characteristics. During a period of 11 months, 56 stool samples taken from diarrheic patients hospitalized in the emergency room of the Medical Center UC Davis and 14 environmental samples were cultured for isolation of C. difficile strains. Eighteen C. difficile strains were isolated from stool samples cultured on selective TCCCA plates and 5 strains from environmental samples using Rodac plates. Eleven toxigenic (TcdA+/TcdB+), 6 non-toxigenic (TcdA-/TcdB-) and unique toxin A-negative/toxin B-positive (TcdA-/TcdB+) C. difficile strains were detected among patients' isolates and 3 toxigenic and 2 non-toxigenic strains-among environmental samples. The majority of C. difficile-positive patients were treated previously by antibiotics. Four strains isolated from patients' fecal samples and one strain isolated from the environment demonstrated high-level resistance to erythromycin and clindamycin (MIC >256mug/mL). The results obtained by AP-PCR and PCR-ribotyping revealed genetic heterogeneity among the strains isolated from patients' fecal samples. However, similarity was observed among environmental strains and strains isolated from patients' fecal samples. Considering the importance of emergency room patients as a potential source of C. difficile strains, it appears to be important examine these patients for C. difficile before transfer to the other hospital units.     

Eremomycin in the treatment of antibiotic-associated colitis in golden hamsters]

The efficacy of eremomycin, a new glycopeptide antibiotic, was studied on a model of antibiotic-associated colitis in golden hamsters. The colitis was induced by intraperitoneal or intragastric administration of lincomycin. In a dose of 100 mg/kg administered orally once a day for 5 days eremomycin protected the animals from the lincomycin-induced colitis: some animals survived, the others died in later periods. When the animals were infected with a pathogenetic strain of Clostridium difficile followed by exposure to lincomycin the use of eremomycin produced the similar effect.     

Overuse of high stability antibiotics and its consequences in public and environmental health

In this paper the ecological aspects of widespread antibiotic consumption are described. Many practitioners, veterinarians, breeders, farmers and analysts work on the assumption that a antibiotics undergo spontaneous degradation. It is well documented that the indiscriminate use of antibiotics has led to the water contamination, selection and dissemination of antibiotic-resistant organisms, alteration of fragile ecology of the microbial ecosystems. The damages caused by the overuse of antibiotics include hospital, waterborne and foodborne infections by resistant bacteria, enteropathy (irritable bowel syndrome, antibiotic-associated diarrhea etc.), drug hypersensitivity, biosphere alteration, human and animal growth promotion, destruction of fragile interspecific competition in microbial ecosystems etc. The consequences of heavy antibiotic use for public and environmental health are difficult to assess: utilization of antibiotics from the environment and reduction of irrational use is the highest priority issue. This purpose may be accomplished by bioremediation, use of probenecid for antibiotic dosage reduction and by adoption of hospital infections methodology for control resistance in natural ecosystems.     

Evaluation of the effect of medicines on biological properties of Clostridium difficile

The presence of the persistence factors (anti-lysozyme and anti-complement activity) in the vegetative forms of C. difficile was experimentally proved. The effect of different medicines (vitamins B1, B6 and C, prebiotic inulin, probiotics Bifidumbacterin and Enterol) on the persistence factors of C. difficile and microbial resistance to vancomycin, thienam, lincomycin, clindamycin was evaluated. The anti-lysozyme and anti-complement activity of C. difficile was found to decrease under the influence of vitamins B1, B6, C, inulin, exometabolites of bifidobacteria. Under the impact of the preparations used in this study changes in the sensitivity of C. difficile to antibiotics of the lincoamide, carbapenem, glycopeptide groups were found to occur. The data obtained reveal one of the possible mechanisms of the corrective action of the medicines under study on the intestinal microbiocenosis in patients with antibiotic-associated colitis.     

Feasibility of Outpatient Self-Administration of Parenteral Antibiotics

It is customary to treat patients with infective endocarditis or osteomyelitis for a prolonged period in hospital with parenteral antibiotics. It was felt that it might be feasible to allow parenteral administration of antibiotics by the patients themselves at home. Results in 13 patients who administered antibiotics parenterally themselves (experimental group) were compared with those in 7 patients (control group) treated entirely within the hospital. Antibiotic-related complications were similar in both groups. There was no instance of infection of the intravenous cannula in either group. The average daily cost of antibiotic therapy decreased from $243.22 for inpatients to $69.35 for outpatients. The average cost of illness was $6,357.22 in the experimental group and $10,022.23 in the control group. If patients are carefully selected and well educated, the outpatient self-administration of antibiotics parenterally is both economical and safe.     

Antimicrobial Susceptibility of Clostridium difficile from Different Sources

A total of 79 Clostridium difficile strains from healthy young and elderly adults, elderly patients without gastrointestinal disease, elderly patients receiving antibiotics without gastrointestinal complications, and elderly patients with antibiotic-associated diarrhea or pseudomembranous colitis were tested for their susceptibilities to 24 antimicrobial agents. All of the 79 strains were inhibited by low concentrations of rifampicin, metronidazole, fusidic acid, vancomycin, ampicillin, and penicillin G. The strains were highly resistant to aminoglycosides, trimethoprim, sulfamethoxazole, nalidixic acid, and cycloserine and often resistant to neomycin, cefoxitin, and cefalexin. Wide variations in the susceptibility of C. difficile strains to erythromycin, clindamycin, lincomycin, chloramphenicol, and tetracycline were found. Strains resistant to erythromycin, clindamycin, and lincomycin were more frequently found among strains isolated from elderly adults than those isolated from young adults, with particularly high frequency among strains isolated from elderly patients receiving antibiotics. None of the 23 strains isolated from healthy young adults was resistant to chloramphenicol. All of the 14 strains resistant to erythromycin, clindamycin, lincomycin, and chloramphenicol were sensitive to tetracycline and all of the 15 strains resistant to erythromycin, clindamycin, lincomycin, and tetracycline were sensitive to chloramphenicol. Only one out of 19 tetracycline-resistant strains was highly toxigenic, whereas 42 (70%) of 60 sensitive strains were highly toxigenic.     

Structure and mode of action of clostridial glucosylating toxins: the ABCD model

Toxins A and B, which are the major virulence factors of antibiotic-associated diarrhea and pseudomembranous colitis caused by Clostridium difficile, are the prototypes of the family of clostridial glucosylating toxins. The toxins inactivate Rho and Ras proteins by glucosylation. Recent findings on the autocatalytic processing of the toxins and analysis of the crystal structures of their domains have made a revision of the current model of their actions on the eukaryotic target cells necessary.     

Comparative study of the therapeutic effect of the glycopeptide antibiotics eremomycin, vancomycin and ristomycin in a model of antibiotic-associated colitis in golden hamsters]

Experiments with a model of intraperitoneal or intragastric lincomycin-induced fatal colitis indicated that eremomycin, vancomycin and ristomycin administered orally in daily doses of 100, 100 and 200 mg/kg, respectively, for 5 days protected the animals from development of antibiotic-associated colitis (AAC), which was evident from prolongation of their life-span to 10-23 days against 3-9 days in the controls. Eremomycin administered intraperitoneally according to an analogous scheme protected the animals from development of AAC, prevented 45 per cent of the animals from death and prolonged the life-span of the other animals to 15-28 days against 3-9 days in the controls. Vancomycin administered intraperitoneally was somewhat more efficient. Still, unlike eremomycin it had a local irritating effect. The protective effect of ristomycin administered intraperitoneally was much lower than that of vancomycin and eremomycin.     

Identification and susceptibility to antimicrobial agents of strictly anaerobic bacteria isolated from hospitalized patients

The aim of this study was to identify anaerobic strains isolated in 2001 from clinical specimens obtained from patients of Warsaw hospital and to evaluate a susceptibility of these strains to antimicrobial agents. In 2001 two hundred and twenty five clinical strains of obligate anaerobes were cultured, which were identified in the automatic ATB system (bioMérieux, France) using biochemical tests API 20 A. Drug-susceptibility of strains was determined also in ATB system with the use of ATB ANA strips. C. difficile strains were isolated on selective CCCA medium. Toxins A/B of C. difficile directly in stool specimens were detected by means of ELISA test (TechLab, USA). Fifty four strains of Gram-negative anaerobes (B. fragilis strains dominated) and 171 strains of Gram-positive anaerobes (the greatest number of strains belonged to genus Peptostreptococcus) were cultured from clinical specimens. In the cases of antibiotic-associated diarrhea 28 C. difficile strains were isolated and C. difficile toxins A/B were detected in 39 stool samples. The most active in vitro antimicrobials against Gram-negative anaerobes were metronidazole, imipenem, ticarcillin combined with clavulanic acid and piperacillin with tazobactam. Gram-positive, clinical strains of anaerobes were the most susceptible in vitro to beta-lactam antibiotics combined with beta-lactamase inhibitors (amoxicillin/clavulanate, piperacillin/tazobactam, ticarcillin/clavulanate) and imipenem.     

儿科病房抗生素相关性腹泻的临床观察

目的 观察儿科病房抗生素相关性腹泻（antibiotic associated diarrhea,AAD）的临床表现。方法 对983例使用抗生素的患儿进行分析,根据是否发生AAD分为两组,AAD组共有76例患儿,未发生AAD的对照组有907例患儿。分析AAD组患儿使用抗生素的情况,并对两组患儿的基本情况进行比较分析。结果 对AAD患儿抗生素使用种类进行分析,发现导致AAD的抗生素主要有三类,其中美洛西林/舒巴坦使用率最高,为18.4%,其次为美洛西林、头孢哌酮/舒巴坦和阿奇霉素,均为14.5%。并且,AAD的发生与性别无关（P>0.05）。但是AAD在体重较轻、低龄、抗生素使用时间较长和抗生素联用患儿中多发（P<0.05）。这些因素均会导致患儿住院时间延长并出现重要器官损伤现象。结论 儿科病房中抗生素的使用要合理科学,尽量减少AAD的发生。     

The search for disease-associated compositional shifts in bowel bacterial communities of humans

The bowels of humans contain resident bacterial communities, the members of which are numerous and biodiverse. Changes in the composition of bowel communities is accepted to occur in relation to antibiotic-associated colitis of the elderly, but compositional alterations could also be relevant to allergic diseases in children and inflammatory bowel diseases (i.e. Crohn's disease and ulcerative colitis). It is timely, therefore, to reflect on current knowledge of the bacterial community of the human bowel in relation to disease. Modern analytical methods provide tools by which compositional shifts in bacterial communities can be detected, but inadequate bowel-sampling procedures and poorly designed studies hamper progress. Moreover, demonstration that population shifts cause the disease and are not just reflections of a diseased state is necessary. Therefore, important challenges remain for bacteriologists in investigations of the bowel bacterial community in relation to disease.     

宏转录组测序分析老年抗生素相关性腹泻患者肠道菌群组成及耐药通路特点

为探究老年抗生素相关性腹泻(AAD)患者肠道菌群结构变化的特点以及与细菌耐药性之间的关联。

对来自华山医院老年科的6名老年AAD患者的肠道菌群进行宏转录组测序, 并以另5名相同饮食标准下接受抗生素治疗但未发生腹泻的患者作为对照, 深入分析老年AAD患者肠道菌群物种组成及耐药通路变化。

AAD组物种丰度和多样性均低于对照组, 且两组菌群组成在不同分类学水平上存在明显差异(P < 0.05)。KEGG比对结果显示, AAD组多条抗生素耐药通路的表达量均有显著上调, 包括与β-内酰胺类抗生素耐药相关的青霉素结合蛋白pbp1B、pbp5、金属β-内酰胺酶bla2, β-内酰胺酶基因表达调节因子ampR、ampC等, 与万古霉素耐药相关的VanX、VanB、VanW和VanH等。另外, mlaC、natB、znuC、tcyB、tcyC等53条ATP结合盒超家族(ABC转运蛋白)相关通路在AAD组中显著上调。

菌群结构变化、某些优势菌属的扩张、菌群失调相关的代谢变化以及抗生素耐药性等因素与老年人AAD有潜在联系。

     

In vivo lysogenization of a Clostridium difficile bacteriophage ФCD119

Clostridium difficile is a nosocomial pathogen identified as the cause of antibiotic-associated diarrhea and colitis. In this study, we have documented the lysogeny of a C.?difficile bacteriophage in hamsters during C.?difficile infection. The lysogens isolated from the hamsters were toxin typed and their phage integration site was confirmed by PCR. Through toxin ELISA it was found that the toxin production in the in?vivo isolated lysogens was affected due to ФCD119 lysogenization as in the case of in?vitro isolated ФCD119 lysogens. Together our findings indicate that a baceriophage can lysogenize its C.?difficile host even during the infection process and highlights the importance of lysogeny of C.?difficile phages as an evolutionary adaptation for survival.     

Diagnosis of pseudomembranous colitis.

Twenty-eight patients with histologically proved pseudomembranous colitis have been seen in one hospital since July 1975. All patients with the disease had received antibiotics, six for infections not requiring operations; the other 22 cases all occurred after major surgery. All the patients had diarrhoea; six patients also had fever with clinical signs of sepsis, and three had abdominal pain thought to be due to anastomotic dehiscence after colonic resection. Pseudomembranous colitis was associated with white blood counts over 15 000/mm3 in 17 patients and albumin concentrations of less than 30 g/1 in 18. Pseudomembranous colitis was an incidental finding at necropsy in two of six patients who had not had an operation. Of the 22 patients who had had major surgery, nine died from this complication; in all except two of these cases the diagnosis was made only at necropsy. If pseudomembranous colitis is suspected on clinical grounds or if there is an unexplained complication after colorectal surgery repeat sigmoidoscopy and testing for faecal toxins should be carried out to establish the diagnosis so that prompt supportive treatment can be given.     

Cytotoxic component(s) of Klebsiella oxytoca on HEp-2 cells

A cytotoxic component(s) was detected in culture filtrates of Klebsiella oxytoca isolated from patients with antibiotic-associated hemorrhagic colitis. Eleven of 12 isolates exhibited cytotoxicity on HEp-2 cells. The cytotoxic activity of K. oxytoca strain MH43-1 was stable for the treatment of 60 C for 30 min, but inactivated by the treatment of 100 C for 15 min. This cytotoxicity was not destroyed by the treatment with trypsin or pronase, and the component was filtrable through a membrane filter which cut off molecular weight 5,000.     

Chest diseases-epitomes of progress: new diagnostic techniques for thrombophlebitis

In 1974 in California, 72,645 patients were admitted to hospital for backache. In 50 percent of these patients there was a diagnosis compatible with discogenic disease. Surgical treatment was done in 27 percent of the patients admitted to hospital. Total figures were determined for hospital costs and the costs of physician-related services. Costs for surgical treatment exceeded medical costs. Extrapolated to a national scale, it appears that the national cost for patients in hospital because of backache in 1974 was $1.38 billion. This does not include outpatient care expense or loss of income.     

Passive immunisation of hamsters against Clostridium difficile infection using antibodies to surface layer proteins

Clostridium difficile is a major cause of antibiotic-associated diarrhoea and the primary cause of pseudomembraneous colitis in hospitalised patients. We assessed the protective effect of anti-surface layer protein (SLP) antibodies on C. difficile infection in a lethal hamster challenge model. Post-challenge survival was significantly prolonged in the anti-SLP treated group compared with control groups (P=0.0281 and P=0.0283). The potential mechanism of action of the antiserum was shown to be through enhancement of C. difficile phagocytosis. This report indicates that anti-SLP antibodies can modulate the course of C. difficile infection and may therefore merit closer investigation for use as constituents of multi-component vaccines against C. difficile associated diarrhoea.