Sporicidal Activity of the KMT reagent in its vapor phase against Geobacillus stearothermophilus Spores

In an investigation of the sporicidal activity of the KMT reagent, a vapor phase study was performed using five kinds of carriers contaminated with Geobacillus stearothermophilus spores. When 25 ml of the KMT reagent was vaporized in a chamber (capacity; approximately 95 liters), the 2-step heating method (vaporization by a combination of low temperature and high temperature) showed the most effective sporicidal activity in comparison with the 1-step heating method (rapid vaporization). The 2-step heating method appeared to be related to the sporicidal activity of vaporized KMT reagent, i.e., ethanol and iodine, which vaporized mainly when heated at a low temperature such as 55 C, and acidic water, which vaporized mainly when heated at a high temperature such as 300 C. We proposed that the KMT reagent can be used as a new disinfectant not only in the liquid phase but also in the vapor phase in the same way as peracetic acid and hydrogen peroxide.     

Fate of Ingested Clostridium difficile Spores in Mice

Clostridium difficile infection (CDI) is a leading cause of antibiotic-associated diarrhea, a major nosocomial complication. The infective form of C. difficile is the spore, a dormant and resistant structure that forms under stress. Although spore germination is the first committed step in CDI onset, the temporal and spatial distribution of ingested C. difficile spores is not clearly understood. We recently reported that CamSA, a synthetic bile salt analog, inhibits C. difficile spore germination in vitro and in vivo. In this study, we took advantage of the anti-germination activity of bile salts to determine the fate of ingested C. difficile spores. We tested four different bile salts for efficacy in preventing CDI. Since CamSA was the only anti-germinant tested able to prevent signs of CDI, we characterized CamSa’s in vitro stability, distribution, and cytotoxicity. We report that CamSA is stable to simulated gastrointestinal (GI) environments, but will be degraded by members of the natural microbiota found in a healthy gut. Our data suggest that CamSA will not be systemically available, but instead will be localized to the GI tract. Since in vitro pharmacological parameters were acceptable, CamSA was used to probe the mouse model of CDI. By varying the timing of CamSA dosage, we estimated that C. difficile spores germinated and established infection less than 10 hours after ingestion. We also showed that ingested C. difficile spores rapidly transited through the GI tract and accumulated in the colon and cecum of CamSA-treated mice. From there, C. difficile spores were slowly shed over a 96-hour period. To our knowledge, this is the first report of using molecular probes to obtain disease progression information for C. difficile infection.     

Proteomic and Genomic Characterization of Highly Infectious Clostridium difficile 630 Spores

Clostridium difficile, a major cause of antibiotic-associated diarrhea, produces highly resistant spores that contaminate hospital environments and facilitate efficient disease transmission. We purified C. difficile spores using a novel method and show that they exhibit significant resistance to harsh physical or chemical treatments and are also highly infectious, with <7 environmental spores per cm² reproducibly establishing a persistent infection in exposed mice. Mass spectrometric analysis identified ∼336 spore-associated polypeptides, with a significant proportion linked to translation, sporulation/germination, and protein stabilization/degradation. In addition, proteins from several distinct metabolic pathways associated with energy production were identified. Comparison of the C. difficile spore proteome to those of other clostridial species defined 88 proteins as the clostridial spore “core” and 29 proteins as C. difficile spore specific, including proteins that could contribute to spore-host interactions. Thus, our results provide the first molecular definition of C. difficile spores, opening up new opportunities for the development of diagnostic and therapeutic approaches.Clostridium difficile is a gram-positive, spore-forming, anaerobic bacterium that can asymptomatically colonize the intestinal tracts of humans and other mammals (3, 30, 39). Antibiotic treatment can result in C. difficile overgrowth and can lead to clinical disease, ranging from diarrhea to life-threatening pseudomembranous colitis, particularly in immunocompromised hosts (2, 4, 7). In recent years, C. difficile has emerged as the major cause of nosocomial antibiotic-induced diarrhea, and it is frequently associated with outbreaks (21, 22). A contributing factor is that C. difficile can be highly infectious and difficult to contain, especially when susceptible patients are present in the same hospital setting (13).Person-to-person transmission of C. difficile is associated with the excretion of highly resistant spores in the feces of infected patients, creating an environmental reservoir that can confound many infection control measures (29, 44). Bacterial spores, which are metabolically dormant cells that are formed following asymmetric cell division, normally have thick concentric external layers, the spore coat and cortex, that protect the internal cytoplasm (15, 42). Upon germination, spores lose their protective external layers and resume vegetative growth (24, 27, 36). Bacillus spores and the spores of most Clostridium species germinate in response to amino acids, carbohydrates, or potassium ions (24, 36). In contrast, C. difficile spores show an increased level of germination in response to cholate derivatives found in bile (40, 41). Thus, spores are well adapted for survival and dispersal under a wide range of environmental conditions but will germinate in the presence of specific molecular signals (24, 36).While the spores of a number of Bacillus species, such as Bacillus subtilis and Bacillus anthracis, and those of other Clostridium species, such as Clostridium perfringens (15, 20), have been well characterized, research on C. difficile spores has been relatively limited. A greater understanding of C. difficile spore biology could be exploited to rationalize disinfection regimes, molecular diagnostics, and the development of targeted treatments such as vaccines. Here we describe a novel method to isolate highly purified C. difficile spores that maintain their resistance and infectious characteristics, thus providing a unique opportunity to study C. difficile spores in the absence of vegetative cells. A thorough proteomic and genomic analysis of the spore provides novel insight into the unique composition and predictive biological properties of C. difficile spores that should underpin future research into this high-profile but poorly understood pathogen.     

Ultrastructural Variability of the Exosporium Layer of Clostridium difficile Spores

The anaerobic sporeformer Clostridium difficile is the leading cause of nosocomial antibiotic-associated diarrhea in developed and developing countries. The metabolically dormant spore form is considered the transmission, infectious, and persistent morphotype, and the outermost exosporium layer is likely to play a major role in spore-host interactions during the first contact of C. difficile spores with the host and for spore persistence during recurrent episodes of infection. Although some studies on the biology of the exosporium have been conducted (J. Barra-Carrasco et al., J Bacteriol 195:3863–3875, 2013, http://dx.doi.org/10.1128/JB.00369-13; J. Phetcharaburanin et al., Mol Microbiol 92:1025–1038, 2014, http://dx.doi.org/10.1111/mmi.12611), there is a lack of information on the ultrastructural variability and stability of this layer. In this work, using transmission electron micrographs, we analyzed the variability of the spore''s outermost layers in various strains and found distinctive variability in the ultrastructural morphotype of the exosporium within and between strains. Through transmission electron micrographs, we observed that although this layer was stable during spore purification, it was partially lost after 6 months of storage at room temperature. These observations were confirmed by indirect immunofluorescence microscopy, where a significant decrease in the levels of two exosporium markers, the N-terminal domain of BclA1 and CdeC, was observed. It is also noteworthy that the presence of the exosporium marker CdeC on spores obtained from C. difficile biofilms depended on the biofilm culture conditions and the strain used. Collectively, these results provide information on the heterogeneity and stability of the exosporium surface of C. difficile spores. These findings have direct implications and should be considered in the development of novel methods to diagnose and/or remove C. difficile spores by using exosporium proteins as targets.     

Detection and Enumeration of Clostridium difficile Spores in Retail Beef and Pork

Recent studies have identified Clostridium difficile in food animals and retail meat, and concern has been raised about the potential for food to act as a source of C. difficile infection in humans. Previous studies of retail meat have relied on enrichment culture alone, thereby preventing any assessment of the level of contamination in meat. This study evaluated the prevalence of C. difficile contamination of retail ground beef and ground pork in Canada. Ground beef and ground pork were purchased from retail outlets in four Canadian provinces. Quantitative and enrichment culture was performed. Clostridium difficile was isolated from 28/230 (12%) samples overall: 14/115 (12%) ground beef samples and 14/115 (12%) ground pork samples (P = 1.0). For ground beef, 10/14 samples (71%) were positive by enrichment culture only. Of the 4 ground beef samples that were positive by direct culture, 20 spores/g were present in 2 while 120 and 240 spores/g were present in 1 each. For ground pork, 10/14 (71%) samples were positive by enrichment culture only. Of the 4 ground pork samples that were positive by direct culture, 20 spores/g were present in 3 while 60 spores/g were present in 1. Ribotype 078 predominated, consistent with some previous studies of C. difficile in food animals. Ribotype 027/North American pulsotype 1 was also identified in both retail beef and pork. This study has identified relatively common contamination of retail ground beef and pork with C. difficile spores; however, the levels of contamination were very low.Clostridium difficile is an important cause of enteric disease in humans. It is the most commonly diagnosed cause of hospital- and antimicrobial agent-associated diarrhea in people, and recent evidence suggests that it may be emerging as an important community-associated pathogen (2, 5). In addition to humans, C. difficile can be found in the intestinal tracts of a variety of animal species, including food animals, such as cattle and pigs (7, 10, 13). Clostridium difficile has also been found in retail meat (11, 12, 17), and concerns about the role of food in the epidemiology of community-associated C. difficile infection (CA-CDI) have been expressed (5, 8, 15).Initial studies have reported isolation of C. difficile from 4.6 to 45% of retail meat samples (11, 12, 17). However, all studies have used broth enrichment protocols, which could detect very low spore numbers and provide no information about the number of organisms present in a sample. No studies have evaluated numbers of C. difficile spores in food. While the infectious dose is not known, an understanding of the level of contamination may be an important factor in determining the relevance of contamination of food. Additionally, the use of different methods between studies hampers comparison of results. Recently a study was performed to evaluate different methods for qualitative and quantitative detection of C. difficile (21). This study determined that the detection threshold of enrichment culture could be at least as low as 10 spores/g of meat. It also determined that quantitative culture can accurately determine the level of contamination in experimentally inoculated meat samples, albeit with a higher detection threshold. The objective of this study was to determine the prevalence of C. difficile contamination of retail ground beef and ground pork using both qualitative and quantitative methods.     

Temperature-Induced Changes in the Sporicidal Activity and Chemical Properties of Glutaraldehyde

Freshly prepared 2% acid and alkaline glutaraldehyde solutions were stored at 4, 20, and 37 C. At intervals, samples were removed and changes in pH, ultraviolet spectrum, and sporicidal activity (against Bacillus pumilus spores) were recorded. Alkaline solutions stored at 4 C showed little changes in these properties, whereas such solutions stored at 37 C became turbid and showed a decrease in pH, marked changes in ultraviolet spectrum, and an almost complete loss of sporicidal activity. Intermediate results were obtained with alkaline solutions stored at 20 C. In contrast, acid 2% glutaraldehyde solutions (initial pH 3.5) showed comparatively few changes in their properties. Treatment of spores with freshly prepared glutaraldehyde solutions (0.5%) at temperature above 40 C reduced the effect of pH on sporicidal activity.     

Contribution of Spores to the Ability of Clostridium difficile To Adhere to Surfaces

Clostridium difficile is the commonest cause of hospital-acquired infection in the United Kingdom. We characterized the abilities of 21 clinical isolates to form spores; to adhere to inorganic and organic surfaces, including stainless steel and human adenocarcinoma cells; and to germinate. The composition of culture media had a significant effect on spore formation, as significantly more spores were produced in brain heart infusion broth (Student''s t test; P = 0.018). The spore surface relative hydrophobicity (RH) varied markedly (14 to 77%) and was correlated with the ability to adhere to stainless steel. We observed no correlation between the ribotype and the ability to adhere to steel. When the binding of hydrophobic (DS1813; ribotype 027; RH, 77%) and hydrophilic (DS1748; ribotype 002; RH, 14%) spores to human gut epithelial cells at different stages of cell development was examined, DS1813 spores adhered more strongly, suggesting the presence of surface properties that aid attachment to human cells. Electron microscopy studies revealed the presence of an exosporium surrounding DS1813 spores that was absent from spores of DS1748. Finally, the ability of spores to germinate was found to be strain and medium dependent. While the significance of these findings to the disease process has yet to be determined, this study has highlighted the importance of analyzing multiple isolates when attempting to characterize the behavior of a bacterial species.     

Triggering Germination Represents a Novel Strategy to Enhance Killing of Clostridium difficile Spores

Background

Clostridium difficile is an anaerobic, spore-forming bacterium that is the most common cause of healthcare-associated diarrhea in developed countries. Control of C. difficile is challenging because the spores are resistant to killing by alcohol-based hand hygiene products, antimicrobial soaps, and most disinfectants. Although initiation of germination has been shown to increase susceptibility of spores of other bacterial species to radiation and heat, it was not known if triggering of germination could be a useful strategy to increase susceptibility of C. difficile spores to radiation or other stressors.

Principal Findings

Here, we demonstrated that exposure of dormant C. difficile spores to a germination solution containing amino acids, minerals, and taurocholic acid resulted in initiation of germination in room air. Germination of spores in room air resulted in significantly enhanced killing by ultraviolet-C (UV-C) radiation and heat. On surfaces in hospital rooms, application of germination solution resulted in enhanced eradication of spores by UV-C administered by an automated room decontamination device. Initiation of germination under anaerobic, but not aerobic, conditions resulted in increased susceptibility to killing by ethanol, suggesting that exposure to oxygen might prevent spores from progressing fully to outgrowth. Stimulation of germination also resulted in reduced survival of spores on surfaces in room air, possibly due to increased susceptibility to stressors such as oxygen and desiccation.

Conclusions

Taken together, these data demonstrate that stimulation of germination could represent a novel method to enhance killing of spores by UV-C, and suggest the possible application of this strategy as a means to enhance killing by other agents.     

Chemical Sensitization of Clostridium botulinum Spores to Radiation in Meat

Beef ground round inoculated with 1,000,000 spores of Clostridium botulinum 33-A per gram and containing various additives was exposed to gamma radiation. Spores were inactivated in samples (irradiated at 2.0, 2.5, and 3.0 Mrad) which contained sodium nitrate (1,000 ppm) plus sodium chloride (2.5%). Similar results were obtained when sodium nitrite (200 ppm) was substituted for sodium nitrate, except that there was evidence of spore survival in 1 of 120 cans irradiated at 2.0 Mrad. Spore destruction was based upon the absence of spores and mouse-lethal toxin in meat subcultures made from cans incubated at 35 C for 120 days. Spores were not destroyed when exposed to 2.5 or 3.0 Mrad in the absence of sodium nitrate, sodium nitrite, or sodium chloride. Furthermore, the use of these chemicals individually, together with radiation, was ineffective. The additives alone in the absence of radiation also did not cause spore destruction. Radiation levels of 2.0, 2.5, and 3.0 Mrad, when used with sodium chloride at 1.5 or 2.0% and sodium nitrate at 500 ppm or sodium nitrite at 100 ppm, were ineffective.     

Use of Purified Clostridium difficile Spores To Facilitate Evaluation of Health Care Disinfection Regimens

Clostridium difficile is a major cause of antibiotic-associated diarrheal disease in many parts of the world. In recent years, distinct genetic variants of C. difficile that cause severe disease and persist within health care settings have emerged. Highly resistant and infectious C. difficile spores are proposed to be the main vectors of environmental persistence and host transmission, so methods to accurately monitor spores and their inactivation are urgently needed. Here we describe simple quantitative methods, based on purified C. difficile spores and a murine transmission model, for evaluating health care disinfection regimens. We demonstrate that disinfectants that contain strong oxidizing active ingredients, such as hydrogen peroxide, are very effective in inactivating pure spores and blocking spore-mediated transmission. Complete inactivation of 10⁶ pure C. difficile spores on indicator strips, a six-log reduction, and a standard measure of stringent disinfection regimens require at least 5 min of exposure to hydrogen peroxide vapor (HPV; 400 ppm). In contrast, a 1-min treatment with HPV was required to disinfect an environment that was heavily contaminated with C. difficile spores (17 to 29 spores/cm²) and block host transmission. Thus, pure C. difficile spores facilitate practical methods for evaluating the efficacy of C. difficile spore disinfection regimens and bringing scientific acumen to C. difficile infection control.Clostridium difficile is a Gram-positive, spore-forming, anaerobic bacterium that is a major cause of health care-acquired infections and antibiotic-associated diarrhea (2). In recent years, several genetic variants of C. difficile have emerged as important health care pathogens (6). Perhaps most notable is the “hypervirulent” variant, commonly referred to as PCR ribotype 027/restriction endonuclease analysis (REA) group BI, that produces elevated levels of toxins TcdA and TcdB (17, 19). Other virulent ribotypes that display extensive heterogeneity among their toxin protein sequences (26) and gene activities (8) have emerged. Using whole-genome sequencing, we demonstrated that there are broad genetic differences between the entire genomes of several common variants, including ribotype/REA group variants 012/R, 017/CF, and 027/BI used in this study (12, 27, 31). In contrast, phylogeographic analysis of 027/BI isolates from Europe and the United States demonstrates that this clade is extremely clonal and implies recent transcontinental spread of hypervirulent C. difficile (12).C. difficile is distinct from many other health care pathogens because it produces highly infectious spores that are shed into the environment (25, 28). C. difficile spores can resist disinfection regimens that normally inactivate other health care pathogens, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, therefore challenging current infection control measures (2). A multifaceted approach is normally used to control C. difficile in health care facilities (32). Interventions include antimicrobial stewardship, increased clinical awareness, patient isolation (11), and enhanced environmental disinfection regimens based on hydrogen peroxide (H₂O₂) vapor (HPV) (4). While attempts to break the spore-mediated infection cycle and interrupt these efficient routes of transmission are important for infection control measures, there is little quantitative evidence indicating which interventions are most effective (7). Here we describe the exploitation of pure C. difficile spores (16) and a murine transmission model (15) in simple, practical methods to quantitatively monitor the impact of health care disinfection regimens on C. difficile viability. These methods can be used to optimize disinfection regimens targeted at C. difficile.     

Spores of Clostridium difficile clinical isolates display a diverse germination response to bile salts

Clostridium difficile spores play a pivotal role in the transmission of infectious diarrhoea, but in order to cause disease spores must complete germination and return to vegetative cell growth. While the mechanisms of spore germination are well understood in Bacillus, knowledge of C. difficile germination remains limited. Previous studies have shown that bile salts and amino acids play an important role in regulating the germination response of C. difficile spores. Taurocholate, in combination with glycine, can stimulate germination, whereas chenodeoxycholate has been shown to inhibit spore germination in a C. difficile clinical isolate. Our recent studies of C. difficile sporulation characteristics have since pointed to substantial diversity among different clinical isolates. Consequently, in this study we investigated how the germination characteristics of different C. difficile isolates vary in response to bile salts. By analysing 29 isolates, including 16 belonging to the BI/NAP1/027 type, we show that considerable diversity exists in both the rate and extent of C. difficile germination in response to rich medium containing both taurocholate and glycine. Strikingly, we also show that although a potent inhibitor of germination for some isolates, chenodeoxycholate does not inhibit the germination, or outgrowth, of all C. difficile strains. Finally, we provide evidence that components of rich media may induce the germination of C. difficile spores, even in the absence of taurocholate. Taken together, these data suggest that the mechanisms of C. difficile spore germination in response to bile salts are complex and require further study. Furthermore, we stress the importance of studying multiple isolates in the future when analysing the nutrients or chemicals that either stimulate or inhibit C. difficile spore germination.     

Novel Strategies for Enhanced Removal of Persistent Bacillus anthracis Surrogates and Clostridium difficile Spores from Skin

Background

Removing spores of Clostridium difficile and Bacillus anthracis from skin is challenging because they are resistant to commonly used antimicrobials and soap and water washing provides only modest efficacy. We hypothesized that hygiene interventions incorporating a sporicidal electrochemically generated hypochlorous acid solution (Vashe^®) would reduce the burden of spores on skin.

Methods

Hands of volunteers were inoculated with non-toxigenic C. difficile spores or B. anthracis spore surrogates to assess the effectiveness of Vashe solution for reducing spores on skin. Reduction in spores was compared for Vashe hygiene interventions versus soap and water (control). To determine the effectiveness of Vashe solution for removal of C. difficile spores from the skin of patients with C. difficile infection (CDI), reductions in levels of spores on skin were compared for soap and water versus Vashe bed baths.

Results

Spore removal from hands was enhanced with Vashe soak (>2.5 log₁₀ reduction) versus soap and water wash or soak (~2.0 log₁₀ reduction; P <0.05) and Vashe wipes versus alcohol wipes (P <0.01). A combined approach of soap and water wash followed by soaking in Vashe removed >3.5 log₁₀ spores from hands (P <0.01 compared to washing or soaking alone). Bed baths using soap and water (N =26 patients) did not reduce the percentage of positive skin cultures for CDI patients (64% before versus 57% after bathing; P =0.5), whereas bathing with Vashe solution (N =21 patients) significantly reduced skin contamination (54% before versus 8% after bathing; P =0.0001). Vashe was well-tolerated with no evidence of adverse effects on skin.

Conclusions

Vashe was safe and effective for reducing the burden of B. anthracis surrogates and C. difficile spores on hands. Bed baths with Vashe were effective for reducing C. difficile on skin. These findings suggest a novel strategy to reduce the burden of spores on skin.     

Bactericidal activity of telavancin,vancomycin and metronidazole against Clostridium difficile

We compared the time-kill activities of telavancin, vancomycin and metronidazole at concentrations of 2 times, 4 times, and 8 times their respective MICs against five Clostridium difficile strains including REA type BI, using inocula that contained predominantly either vegetative cells or spores. Telavancin MICs (0.125–0.25 μg/ml) were 2–8-fold lower than those of vancomycin. Telavancin was bacteriostatic, reducing the inoculum by 1–2.5 log₁₀ after 24 h. No major differences occurred with the different inoculum forms or the REA types. Although telavancin MICs were 2–8 times lower than vancomycin, both demonstrated similar bacteriostatic activity against C. difficile while metronidazole was bactericidal.     

Synthesis and antibacterial activity against Clostridium difficile of novel demethylvancomycin derivatives

To explore the structure-activity relationships (SAR) of demethylvancomycin (2) and find more effective new chemical entities than known glycopeptides for the treatment of Clostridium difficile (C. difficile), 17 novel N-substituted (N-arylmethylene or -aliphatic substituents) demethylvancomycin derivatives were prepared. These analogues have been evaluated in vitro for their antibacterial activities against C. difficile and Enterococcus faecium (E. faecium). Compounds 5d, 5h, and 5i with N-arylmethylene substituents, structurally similar to Oritavancin, showed more potent antibacterial activity against C. difficile than vancomycin (1) or demethylvancomycin (2). Meanwhile, compound 5k with an undecyl side chain showed the most potent antibacterial activity against E. faecium (vancomycin-resistant strain).     

Prebiotic-non-digestible oligosaccharides preference of probiotic bifidobacteria and antimicrobial activity against Clostridium difficile

Bifidobacterium breve 46, Bifidobacterium lactis 8:8 and Bifidobacterium longum 6:18 and three reference strains B. breve CCUG 24611, B. lactis JCM 10602, and Bifidobacterium pseudocatenulatum JCM 1200 were examined for acid and bile tolerance, prebiotic utilization and antimicrobial activity against four Clostridium difficile (CD) strains including the hypervirulent strain, PCR ribotype NAP1/027. B. lactis 8:8 and B. lactis JCM 10602 exhibited a high tolerance in MRSC broth with pH 2.5 for 30 min. B. breve 46 and B. lactis 8:8 remained 100% viable in MRSC broth with 5% porcine bile after 4 h. All six strains showed a high prebiotic degrading ability (prebiotic score) with galactooligosaccharides (GOS), isomaltooligosaccharides (IMOS) and lactulose as carbon sources and moderate degradation of fructooligosaccharides (FOS). Xylooligosaccharides (XOS) was metabolized to a greater extent by B. lactis 8:8, B. lactis JCM 10602, B. pseudocatenulatum JCM 1200 and B. longum 6:18 (prebiotic score >50%). All strains exhibited extracellular antimicrobial activity (AMA) against four CD strains including the CD NAP1/027. AMA of B. breve 46, B. lactis 8:8 and B. lactis JCM 10602 strains was mainly ascribed to a combined action of organic acids and heat stable, protease sensitive antimicrobial peptides when cells were grown in MRSC broth with glucose and by acids when grown with five different prebiotic-non-digestible oligosaccharides (NDOs). None of C. difficile strains degraded five prebiotic-NDOs. Whole cells of B. breve 46 and B. lactis 8:8 and their supernatants inhibited the growth and toxin production of the CD NAP1/027 strain.     

艰难梭菌特异性鸡卵黄抗体的研制及初步应用

目的制备艰难梭菌菌体特异性鸡卵黄抗体,探讨其对艰难梭菌感染小鼠的治疗作用。方法建立艰难梭菌相关腹泻(CDAD)小鼠模型,将30只CDAD小鼠随机分为5组,每组6只,以11.86mg/mL、1.186mg/mL、0.1186mg/mL艰难梭菌菌体特异性IgY灌胃,设立空白对照组及阴性对照组,1d/次,0.5mL/只,连续3d。末次治疗24h后处死小鼠,取盲肠组织中段制作病理切片;其余盲肠组织进行DAO、D-乳酸和TNF-α含量测定;测定回肠组织含水率。结果阴性对照组和空白对照组小鼠盲肠黏膜脱落伴大量炎细胞浸润;高IgY组小鼠盲肠黏膜完整,未见炎性细胞浸润;中IgY组小鼠盲肠黏膜少量炎细胞浸润;低IgY组小鼠盲肠黏膜上皮细胞脱落,少量炎细胞浸润。高IgY组小鼠盲肠DAO含量均显著高于空白对照组和阴性对照组(P0.01);中IgY组小鼠DAO含量高于阴性对照组(P0.05);中、高IgY组小鼠TNF-α含量均低于低IgY组、空白对照组和阴性对照组(P0.05)。结论艰难梭菌菌体特异性IgY对艰难梭菌感染小鼠具有治疗作用。