[Molecular characteristics and antibiotic resistance of Clostridioides difficile isolated from children in China].

Objective: To understand molecular characteristics and antibiotic resistance of Clostridioides (C.) difficile isolated from children in China, and provide data support the development of disease risk assessment and burden studies. Methods: A total of 155 strains of C. difficile isolated from children aged <12 years in 14 provinces (autonomous regions, municipalities) in China from 2010 to 2023 were used for the analyses on molecular characteristics and antibiotic resistance of C. difficile by PCR and drug susceptibility test. Results: A total of 26 sequence types (STs) and 18 ribotypes (RTs) were identified in the 155 C. difficile isolates, in which ST3 (20.65%), ST54 (16.13%), ST35 (12.90%), and RT012/ICDC007 (14.84%), RT001/ICDC001 (11.61%), RT046/ICDC018 (8.39%) were the most common. One highly virulent strain with RT078 and 27 non-toxin-producing strains were also found; the predominant toxin gene was tcdA+tcdB+cdt-. All the strains were sensitive to metronidazole and vancomycin, and there were 29 multidrug-resistant strains, in which 1 strain was resistant to all the seven antibiotics except for vancomycin and metronidazole. Conclusions: Molecular characteristics and antibiotic resistance of C. difficile in children were similar to those in whole population in China, but there were regional distribution differences. It is necessary to strengthen the routine drug-resistance surveillance for C. difficile infection in children in China.

Hand and environmental hygiene: respective roles for MRSA, multi-resistant gram negatives, Clostridioides difficile, and Candida spp.

Healthcare-associated infections (HAIs) caused by multidrug-resistant organisms (MDROs) represent a global threat to human health and well-being. Because transmission of MDROs to patients often occurs via transiently contaminated hands of healthcare personnel (HCP), hand hygiene is considered the most important measure for preventing HAIs. Environmental surfaces contaminated with MDROs from colonized or infected patients represent an important source of HCP hand contamination and contribute to transmission of pathogens. Accordingly, facilities are encouraged to adopt and implement recommendations included in the World Health Organization hand hygiene guidelines and those from the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology. Alcohol-based hand rubs are efficacious against MDROs with the exception of Clostridiodes difficile, for which soap and water handwashing is indicated. Monitoring hand hygiene adherence and providing HCP with feedback are of paramount importance. Environmental hygiene measures to curtail MDROs include disinfecting high-touch surfaces in rooms of patients with C. difficile infection daily with a sporicidal agent such as sodium hypochlorite. Some experts recommend also using a sporicidal agent in rooms of patients colonized with C. difficile, and for patients with multidrug-resistant Gram-negative bacteria. Sodium hypochlorite, hydrogen peroxide, or peracetic acid solutions are often used for daily and/or terminal disinfection of rooms housing patients with Candida auris or other MDROs. Products containing only a quaternary ammonium agent are not as effective as other agents against C. auris. Portable medical equipment should be cleaned and disinfected between use on different patients. Detergents are not recommended for cleaning high-touch surfaces in MDRO patient rooms, unless their use is followed by using a disinfectant. Facilities should consider using a disinfectant instead of detergents for terminal cleaning of floors in MDRO patient rooms. Education and training of environmental services employees is essential in assuring effective disinfection practices. Monitoring disinfection practices and providing personnel with performance feedback using fluorescent markers, adenosine triphosphate assays, or less commonly cultures of surfaces, can help reduce MDRO transmission. No-touch disinfection methods such as electrostatic spraying, hydrogen peroxide vapor, or ultraviolet light devices should be considered for terminal disinfection of MDRO patient rooms. Bundles with additional measures are usually necessary to reduce MDRO transmission.

Virulence factors, antibiotic susceptibility and sequence type distribution of hospital-associated Clostridioides difficile isolates in Israel, 2020-2022.

Biofilm formation and toxin production are some of the virulence factors of Clostridioides difficile (C. difficile), which causes hospital-acquired C. difficile infection (HA-CDI). This work investigated the prevalence and distribution of different strains recovered from HA-CDI patients hospitalized in 4 medical centres across Israel, and characterized strains' virulence factors and antibiotic susceptibility. One-hundred and eighty-eight faecal samples were collected. C. difficile 's toxins were detected by the CerTest Clostridium difficile GDH + Toxin A + B combo card test kit. Toxin loci PaLoc and PaCdt were detected by whole-genome sequencing (WGS). Multi-locus sequence typing (MLST) was performed to classify strains. Biofilm production was assessed by crystal violet. Antibiotic susceptibility was determined using Etest. Fidaxomicin susceptibility was tested via agar dilution. Sequence type (ST) 42 was the most (13.8%) common strain. All strains harboured the 2 toxins genes; 6.9% had the binary toxin. Most isolates were susceptible to metronidazole (98.9%) and vancomycin (99.5%). Eleven (5.85%) isolates were fidaxomicin-resistant. Biofilm production capacity was associated with ST (p < 0.001). In conclusion, a broad variety of C. difficile strains circulate in Israel's medical centres. Further studies are needed to explore the differences and their contribution to HA-CDI epidemiology.

Structure-Activity Relationship of Inositol Thiophosphate Analogs as Allosteric Activators of Clostridioides difficile Toxin B.

Clostridioides difficile is a bacterium that causes life-threatening intestinal infections. Infection symptoms are mediated by a toxin secreted by the bacterium. Toxin pathogenesis is modulated by the intracellular molecule, inositol-hexakisphosphate (IP6). IP6 binds to a cysteine protease domain (CPD) on the toxin, inducing autoproteolysis, which liberates a virulence factor in the cell cytosol. We developed second-generation IP6 analogs designed to induce autoproteolysis in the gut lumen, prior to toxin uptake, circumventing pathogenesis. We synthesized a panel of thiophosphate-/sulfate-containing IP6 analogs and characterized their toxin binding affinity, autoproteolysis induction, and cation interactions. Our top candidate was soluble in extracellular cation concentrations, unlike IP6. The IP6 analogs were more negatively charged than IP6, which improved affinity and stabilization of the CPD, enhancing toxin autoproteolysis. Our data illustrate the optimization of IP6 with thiophosphate biomimetic which are more capable of inducing toxin autoproteolysis than the native ligand, warranting further studies in vivo.

Adaptation mechanisms of Clostridioides difficile to auranofin and its impact on human gut microbiota.

Auranofin (AF), a former rheumatoid polyarthritis treatment, gained renewed interest for its use as an antimicrobial. AF is an inhibitor of thioredoxin reductase (TrxB), a thiol and protein repair enzyme, with an antibacterial activity against several bacteria including C. difficile, an enteropathogen causing post-antibiotic diarrhea. Several studies demonstrated the effect of AF on C. difficile physiology, but the crucial questions of resistance mechanisms and impact on microbiota remain unaddressed. We explored potential resistance mechanisms by studying the impact of TrxB multiplicity and by generating and characterizing adaptive mutations. We showed that if mutants inactivated for trxB genes have a lower MIC of AF, the number of TrxBs naturally present in clinical strains does not impact the MIC. All stable mutations isolated after AF long-term exposure were in the anti-sigma factor of σB and strongly affect physiology. Finally, we showed that AF has less impact on human gut microbiota than vancomycin.

Positive Intervention of Distinct Peptides in Clostridioides difficile Infection in a Mouse Model.

Clostridioides difficile infection (CDI) is a common healthcare-associated infection and the leading cause of gastroenteritis-related deaths worldwide. To investigate the effects of peptide composition of different protein products on CDI, we analyzed and compared the peptide sequences and compositions from Engraulis japonicus and Glycine max using Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). An animal model of CDI was also established to investigate the potential therapeutic effects of these peptides in vivo. The peptide compositions of E. japonicus and G. max differed, with only 11% of the peptide sequences being identical. Oral administration of the tested peptides could reduce intestinal inflammation, repair the intestinal barrier, increase the proportion of beneficial bacteria, and reduce the proportion of harmful bacteria, providing a therapeutic effect against CDI. However, the peptides may differ considerably in some aspects. E. japonicus peptides were superior to G. max peptides in promoting colon epithelial cell proliferation and repairing tight intestinal cell junctions. Interestingly, the two sources of peptides have different effects on the cecal microbiome. E. japonicus peptides can effectively restore the diversity and richness of intestinal microbiota, while G. max peptides have poor regulatory effects on the intestinal microbiota structure. Overall, E. japonicus peptides showed better results than G. max peptides in treating CDI. This study supports the potential treatment of CDI with natural peptides and promotes the development of specialty foods for CDI enteritis. Clostridioides difficile infection (CDI) is a common healthcare-associated infection and the leading cause of gastroenteritis-related deaths worldwide. To investigate the effects of peptide composition of different protein products on CDI, we analyzed and compared the peptide sequences and compositions from Engraulis japonicus and Glycine max using Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). An animal model of CDI was also established to investigate the potential therapeutic effects of these peptides in vivo. The peptide compositions of E. japonicus and G. max differed, with only 11% of the peptide sequences being identical. Oral administration of the tested peptides could reduce intestinal inflammation, repair the intestinal barrier, increase the proportion of beneficial bacteria, and reduce the proportion of harmful bacteria, providing a therapeutic effect against CDI. However, the peptides may differ considerably in some aspects. E. japonicus peptides were superior to G. max peptides in promoting colon epithelial cell proliferation and repairing tight intestinal cell junctions. Interestingly, the two sources of peptides have different effects on the cecal microbiome. E. japonicus peptides can effectively restore the diversity and richness of intestinal microbiota, while G. max peptides have poor regulatory effects on the intestinal microbiota structure.

The impact of 30-day antecedent antibiotic exposure on Clostridioidesdifficile ribotype patterns and the relationship with clinical outcomes: A single center study.

BACKGROUND: Antibiotic exposure is a known risk factor for Clostridioides difficile infection (CDI) and recurrence and can lead to infection with specific C. difficile strains. In this study, we sought to explore the relationship between antecedent antibiotic exposure and C. difficile antimicrobial resistance, and the impact of resistance on clinical outcomes. METHODS: This was a single center retrospective study evaluating patients with CDI between 2011 and 2021. A logistic regression model was used to evaluate the relationship between antecedent antibiotics in the 30 days prior to CDI and resistance among isolates. In addition, an exploratory analysis using a cause-specific Cox proportional hazards model evaluated the association between resistance and a composite outcome of clinical failure, relapse at 30 days or CDI-related death. RESULTS: we analyzed one isolate from 510 patients; resistance was noted in 339 (66.5 %) of the isolates. Exposure to fluoroquinolones and macrolides was associated with 2.4 (95 % CI 1.4-4.4) and 4.7 (95 % CI 1.1-20.5) increased odds of having resistance compared to other antibiotic class exposure, respectively. There were 58 (17.0 %) patients in the resistance group who developed the composite outcome and 24 (14.2 %) patients who lacked resistance who developed the composite outcome (HR 1.32, 95 % CI 0.81-2.14). CONCLUSION: These findings suggest that fluoroquinolone and macrolide exposure were significantly associated with isolating a resistant strain, but we did not find significant differences in clinical outcomes based on the presence of antimicrobial resistance.

Risk of Clostridioides difficile infection following different antibiotics: insights from multi-source medical data.

OBJECTIVE: Antibiotic utilization stands as the strongest modifiable determinant for Clostridioides difficile infection (CDI). However, previous studies have relied on aggregated antibiotic categories, leaving prescribers without detailed comparative risk information for individual antibiotics. The objective of this study was to estimate the risk of CDI comprehensively across specific antibiotics. METHODS: Two methodologies were integrated to access and rank the risk of CDI associated with individual antibiotics or classes. Initially, a network comparison was conducted by analysing data from randomized controlled trials (RCTs). Subsequently, a real-world disproportionality analysis using the Food and Drug Adverse Event Reporting System (FAERS) database complemented and enriched the findings from RCTs. RESULTS: The network comparison, encompassing 61 RCTs with 25,931 patients, revealed that exposure to cefepime [odds ratio (OR) 2.56, 95% confidence interval (CI) 1.20-5.44; P=0.02] and imipenem/cilastatin (OR 3.86, 95% CI 1.61-9.29; P=0.003) exhibited higher frequencies of CDI compared with piperacillin/tazobactam. No significant differences were observed between the carbapenems, albeit a trend indicating higher incidence of CDI with imipenem/cilastatin compared with meropenem (OR 3.89, 95% CI 0.94-16.09). In the FAERS disproportionality analysis, nearly all antibiotics displayed associations with CDI, and CDI risk signals often clustered within the majority of antibiotic classes. Among these, lincomycin demonstrated the strongest association (OR 112.17, 95% CI 51.68-243.43). Additionally, oral third-generation cephalosporins tended to exhibit higher CDI risk signals than other antibiotics. CONCLUSIONS: The findings unveiled substantial diversity in the risk of CDI, both within and between antibiotic classes, providing valuable guidance for clinicians in antibiotic prescription decisions and for initiatives aimed at antibiotic stewardship.

Symbiotic biofilms formed by Clostridioides difficile and bacteroides thetaiotaomicron in the presence of vancomycin.

Vancomycin (VAN) treatment in Clostridioides difficile infection (CDI) suffers from a relatively high rate of recurrence, with a variety of reasons behind this, including biofilm-induced recurrent infections. C. difficile can form monophyletic or symbiotic biofilms with other microbes in the gut, and these biofilms protect C. difficile from being killed by antibiotics. In this study, we analyzed the ecological relationship between Bacteroides thetaiotaomicron and C. difficile and their formation of symbiotic biofilm in the VAN environment. The production of symbiotic biofilm formed by C. difficile and B. thetaiotaomicron was higher than that of C. difficile and B. thetaiotaomicron alone in the VAN environment. In symbiotic biofilms, C. difficile was characterized by increased production of the toxin protein TcdA and TcdB, up-regulation of the expression levels of the virulence genes tcdA and tcdB, enhanced bacterial cell swimming motility and c-di-GMP content, and increased adhesion to Caco-2 cells. The scanning electron microscope (SEM) combined with confocal laser scanning microscopy (CLSM) results indicated that the symbiotic biofilm was elevated in thickness, dense, and had an increased amount of mixed bacteria, while the fluorescence in situ hybridization (FISH) probe and plate colony counting results further indicated that the symbiotic biofilm had a significant increase in the amount of C. difficile cells, and was able to better tolerate the killing of the simulated intestinal fluid. Taken together, C. difficile and B. thetaiotaomicron become collaborative in the VAN environment, and targeted deletion or attenuation of host gut B. thetaiotaomicron content may improve the actual efficacy of VAN in CDI treatment.

Identification of pathways to high-level vancomycin resistance in Clostridioides difficile that incur high fitness costs in key pathogenicity traits.

Clostridioides difficile is an important human pathogen, for which there are very limited treatment options, primarily the glycopeptide antibiotic vancomycin. In recent years, vancomycin resistance has emerged as a serious problem in several gram-positive pathogens, but high-level resistance has yet to be reported for C. difficile, although it is not known if this is due to constraints upon resistance evolution in this species. Here, we show that resistance to vancomycin can evolve rapidly under ramping selection but is accompanied by fitness costs and pleiotropic trade-offs, including sporulation defects that would be expected to severely impact transmission. We identified 2 distinct pathways to resistance, both of which are predicted to result in changes to the muropeptide terminal D-Ala-D-Ala that is the primary target of vancomycin. One of these pathways involves a previously uncharacterised D,D-carboxypeptidase, expression of which is controlled by a dedicated two-component signal transduction system. Our findings suggest that while C. difficile is capable of evolving high-level vancomycin resistance, this outcome may be limited clinically due to pleiotropic effects on key pathogenicity traits. Moreover, our data identify potential mutational routes to resistance that should be considered in genomic surveillance.

Importance of underlying mechanisms for interpreting relative risk of Clostridioides difficile infection among antibiotic-exposed patients in healthcare facilities.

Clostridioides difficile infection (CDI) is a significant public health threat, associated with antibiotic-induced disruption of the normally protective gastrointestinal microbiota. CDI is thought to occur in two stages: acquisition of asymptomatic colonization from ingesting C. difficile bacteria followed by progression to symptomatic CDI caused by toxins produced during C. difficile overgrowth. The degree to which disruptive antibiotic exposure increases susceptibility at each stage is uncertain, which might contribute to divergent published projections of the impact of hospital antibiotic stewardship interventions on CDI. Here, we model C. difficile transmission and CDI among hospital inpatients, including exposure to high-CDI-risk antibiotics and their effects on each stage of CDI epidemiology. We derive the mathematical relationship, using a deterministic model, between those parameters and observed equilibrium levels of colonization, CDI, and risk ratio of CDI among certain antibiotic-exposed patients relative to patients with no recent antibiotic exposure. We then quantify the sensitivity of projected antibiotic stewardship intervention impacts to alternate assumptions. We find that two key parameters, the antibiotic effects on susceptibility to colonization and to CDI progression, are not identifiable given the data frequently available. Furthermore, the effects of antibiotic stewardship interventions are sensitive to their assumed values. Thus, discrepancies between different projections of antibiotic stewardship interventions may be largely due to model assumptions. Data supporting improved quantification of mechanistic antibiotic effects on CDI epidemiology are needed to understand stewardship effects better.

Efficacy of fidaxomicin versus vancomycin in the treatment of Clostridium difficile infection: A systematic meta-analysis.

PURPOSE: To compare the efficacy, recurrence rate, adverse event rate and mortality of fidaxomicin compared with vancomycin in treating different types of Clostridium difficile infection (CDI). METHODS: A systematic search was conducted on PubMed, Embase, Web of Science, Cochrane Library and clinical trial registration databases for research on fidaxomicin versus vancomycin in the treatment of CDI and the retrieval period extended from the establishment of the database to July 22, 2022. A total of 15 studies were included, including 8 RCTs and 7 retrospective cohort studies. RESULTS: Results showed that there was no significant difference in the overall efficacy of the treatment between fidaxomicin and vancomycin, and results in the subgroups of CDI hypervirulent strains and recurrent CDI were obtained, but vancomycin was more effective than fidaxomicin in the treatment of severe CDI (RR = 0.94, 95% CI: 0.90-0.98, P < .01). Results showed that fidaxomicin is superior to vancomycin in terms of 40-day recurrence rate (RR = 0.52, 95% CI: 0.38-0.70, P < .01), 60-day recurrence rate (RR = 0.38, 95% CI: 0.21-0.69, P < .01) and 90-day recurrence rate (RR = 0.62, 95% CI: 0.50-0.77, P < .01). For the recurrence rate of the treatment in CDI hypervirulent strains, severe CDI and recurrent CDI, there was no significant difference between the 2 groups. In addition, there was no significant difference in the incidence of clinical adverse reactions, and same outcomes appeared in all-cause mortality at 40-day, severe CDI and recurrent CDI, but fidaxomicin was superior to vancomycin in all-cause mortality over 60-day (RR = 0.57, 95% CI: 0.34-0.96, P = .03). CONCLUSION: There were no significant differences between fidaxomicin and vancomycin in the treatment of CDI in therapeutic effectiveness and adverse reactions, while fidaxomicin was superior to vancomycin in terms of recurrence rate and long-term mortality, and vancomycin is more effective in treating severe CDI.

Atomic structures of a bacteriocin targeting Gram-positive bacteria.

Due to envelope differences between Gram-positive and Gram-negative bacteria, engineering precision bactericidal contractile nanomachines requires atomic-level understanding of their structures; however, only those killing Gram-negative bacteria are currently known. Here, we report the atomic structures of an engineered diffocin, a contractile syringe-like molecular machine that kills the Gram-positive bacterium Clostridioides difficile. Captured in one pre-contraction and two post-contraction states, each structure fashions six proteins in the bacteria-targeting baseplate, two proteins in the energy-storing trunk, and a collar linking the sheath with the membrane-penetrating tube. Compared to contractile machines targeting Gram-negative bacteria, major differences reside in the baseplate and contraction magnitude, consistent with target envelope differences. The multifunctional hub-hydrolase protein connects the tube and baseplate and is positioned to degrade peptidoglycan during penetration. The full-length tape measure protein forms a coiled-coil helix bundle homotrimer spanning the entire diffocin. Our study offers mechanical insights and principles for designing potent protein-based precision antibiotics.

Chemical optimization and derivatization of micrococcin p2 to target multiple bacterial infections: new antibiotics from thiopeptides.

Antimicrobial resistance poses a significant threat to humanity, and the development of new antibiotics is urgently needed. Our research has focused on thiopeptide antibiotics such as micrococcin P2 (MP2) and derivatives thereof as new anti-infective agents. Thiopeptides are sulfur-rich, structurally complex substances that exhibit potent activity against Gram-positive pathogens and Mycobacteria species, including clinically resistant strains. The clinical development of thiopeptides has been hampered by the lack of efficient synthetic platforms to conduct detailed structure-activity relationship studies of these natural products. The present contribution touches upon efficient synthetic routes to MP2 that laid the groundwork for clinical translation. The medicinal chemistry campaign on MP2 has been guided by computational molecular dynamic simulations and parallel investigations to improve drug-like properties, such as enhancing the aqueous solubility and optimizing antibacterial activity. Such endeavors have enabled identification of promising lead compounds, AJ-037 and AJ-206, against Mycobacterium avium complex (MAC). Extensive in vitro studies revealed that these compounds exert potent activity against MAC species, a subspecies of non-tuberculous mycobacteria (NTM) that proliferate inside macrophages. Two additional pre-clinical candidates have been identified: AJ-024, for the treatment of Clostridioides difficile infections, and AJ-147, for methicillin-resistant Staphylococcus aureus impetigo. Both compounds compare quite favorably with current first-line treatments. In particular, the ability of AJ-147 to downregulate pro-inflammatory cytokines adds a valuable dimension to its clinical use. In light of above, these new thiopeptide derivatives are well-poised for further clinical development.

Antimicrobial susceptibilities, resistance mechanisms and molecular characteristics of toxigenic Clostridioides difficile isolates in a large teaching hospital in Chongqing, China.

OBJECTIVES: Clostridioides difficile ranks among the primary sources of healthcare-related infections and diarrhoea in numerous nations. We evaluated the drug susceptibility and resistance mechanisms of C. difficile isolates from a hospital in Chongqing, China, and identified resistance rates and resistance mechanisms that differed from previous findings. METHODS: The toxin genes and drug resistance genes of clinical strains were detected using Polymerase Chain Reaction (PCR), and these strains were subjected to Multilocus Sequence Typing (MLST). The agar dilution technique was employed for assessing susceptibility of antibiotics. Clinical data collection was completed through a review of electronic medical records. RESULTS: A total of 67 strains of toxin-producing C. difficile were detected. All C. difficile isolates demonstrated susceptibility to both metronidazole and vancomycin. However, resistance was observed in 8.95%, 16.42%, 56.72%, 56.72%, 31.34% and 5.97% of the isolates for tigecycline, tetracycline, clindamycin, erythromycin, moxifloxacin and rifampin, respectively. Among the strains with toxin genotypes A + B + CDT - and belonging to the ST3, six strains exhibited reduced susceptibility to tigecycline (MIC=0.5mg/L) and tetracycline (MIC=8mg/L). The tetA(P) and tetB(P) genes were present in these six strains, but were absent in tetracycline-resistant strains. Resistance genes (ermB, tetM, tetA(P) and tetB(P)) and mutations (in gyrA, gyrB, and rpoB) were identified in resistant strains. CONCLUSIONS: In contrast to prior studies, we found higher proportions of ST3 isolates with decreased tigecycline sensitivity, sharing similar resistance patterns and resistance genes. In the resistance process of tigecycline and tetracycline, the tetA(P) and tetB(P) genes may play a weak role.

Antimicrobial Face Masks and Mask Covers with a Salt-Coated Stacked Spunbond Polypropylene Fabric: Effective Inactivation of Resilient Pathogens and Prevention of Contact Transmission.

In response to the ongoing threat posed by respiratory diseases, ensuring effective transmission protection is crucial for public health. To address the drawbacks of single-use face masks/respirators, which can be a potential source of contact-based transmission, we have designed an antimicrobial face mask and mask covering utilizing a stack of salt-coated spunbond (SB) fabric. This fabric acts as an outer layer for the face mask and as a covering over a conventional mask, respectively. We evaluated the universal antimicrobial performance of the salt-coated three-stacked SB fabric against enveloped/nonenveloped viruses and spore-forming/nonspore-forming bacteria. The distinctive pathogen inactivation efficiency was confirmed, including resistant pathogens such as human rhinovirus and Clostridium difficile. In addition, we tested other filter attributes, such as filtration efficiency and breathability, to determine the optimal layer for salt coating and its effects on performance. Our findings revealed that the outer layer of a conventional face mask plays a crucial role in contact transmission through contaminated face masks and respirators. Through contact transmission experiments using droplets involving three types of contaminants (fluorescent dyes, bacteria, and viruses), the salt-coated stacked SB fabric demonstrated a superior effect in preventing contact transmission compared to SB or meltblown polypropylene fabrics─an issue challenging to existing masks. Our results demonstrate that the use of salt-coated stacked SB fabrics as (i) the outer layer of a mask and (ii) a mask cover over a mask enhances overall filter performance against infectious droplets, achieving high pathogen inactivation and low contact-based transmission while maintaining breathability.

Clinical characteristics of community-onset Clostridioides difficile infections at a tertiary hospital in mainland China: A fourteen-year (2010-2023) retrospective study.

BACKGROUND: Clostridioides difficile infection (CDI) is an increasingly common disease in healthcare facilities and community settings. However, there are limited reports of community-onset CDI (CO-CDI) in China. METHODS: We collected diarrheal stool samples from 3885 patients who went to outpatient department or emergency department in a tertiary hospital in China during 2010-2023, analyzed the correlation between patients' basic information and the detection rate of CDI. Besides, all stool samples from 3885 outpatients included were tested by culturing. Moreover, we randomly selected 89 patients' stools during the 14 years and isolated 126 C. difficile strains from them. The presence of toxin genes (tcdA, tcdB, cdtA, and cdtB) were confirmed by PCR. Toxigenic strains were typed using multilocus sequence typing (MLST). Susceptibility to 9 antimicrobials was evaluated using the E-test. RESULTS: 528 of 3885 patients (13.6 %) with diarrhea were finally diagnosed as CDI. The median age of patients included was 51 years (6 months-95 years), while the median of patients with CDI was older than patients with negative results [55.5 years (6 months-93 years) vs. 50 years (9 months -95 years), p < 0.001]. In winter, patients with diarrhea might be more likely to have CDI. The detection rate of CDI of patients in emergency department was much higher than those in other outpatients (20.7 % vs. 12.4 %, p < 0.001), and did differ from each outpatient departments (p < 0.05). There were 95 isolated strains detected as toxigenic C. difficile. Among these strains, 82 (86.3 %) had the tcdA and tcdB genes (A+B+) and 5 of these 82 strains were positive for the binary toxin genes (cdtA and cdtB) (A+B+CDT+). There were 15 different sequence types (STs) by multilocus sequence typing (MLST), while the most ST was ST-54 (23.2 %). ST types composition was relatively stable over the time span of this study. Some strains had high resistance to ciprofloxacin, clindamycin, and erythromycin. Twenty-three isolates (24.2 %) were multidrug-resistant. CONCLUSIONS: Outpatients with CDI were common among patients having diarrhea during this period in our hospital. Elderly patients and patients went to emergency department may be susceptible to CDI. Based on MLST, the result revealed that the C. difficile isolates had high genetic diversity and maintained stability in this period. All isolates were susceptible to metronidazole and vancomycin, and nearly one quarter of all isolates had multidrug resistance.

Management of Clostridioides difficile infection: an Italian Delphi consensus.

BACKGROUND: Clostridioides difficile infection (CDI), a leading cause of nosocomial deaths, is a microbiota-mediated disease. As such, the use of broader spectrum antibiotics, such as vancomycin and metronidazole, can prime the gastrointestinal tract to become more prone to CDI recurrences. Fidaxomicin, a narrow-spectrum antibiotic, has been demonstrated to be superior in preventing recurrence and in preserving the intestinal microbiota; however, widespread employment worldwide has been hindered due to high acquisition costs. OBJECTIVES: To integrate the currently available guidelines on the management of CDI and to shed light on the timeliest employment of fidaxomicin. METHODS: An expert panel was gathered to obtain consensus using Delphi methodology on a series of statements regarding the management of CDI and on appropriate antibiotic use. RESULTS: Consensus was reached on 21 of the 25 statements addressing the management of CDI. CONCLUSIONS: Delphi methodology was used to achieve consensus on the management of CDI, on the identification of patients at risk of recurrences or severe infection, and on the most appropriate use of fidaxomicin, with the final aim of fostering clinical practice application of treatment algorithms proposed by previous guidelines, in absolute synergy. It could be an important tool to promote more appropriate and cost-effective CDI treatments in European settings with limited resources, like Italy.

Epidemiology of Clostridioides difficile infection at one hospital 10 years after an outbreak of the epidemic C. difficile strain BI/027: changing strain prevalence, antimicrobial susceptibilities, and patient antibiotic exposures.

In contrast to the epidemiology 10 years earlier at our hospital when the epidemic restriction endonuclease analysis (REA) group strain BI accounted for 72% of Clostridioides difficile isolates recovered from first-episode C. difficile infection (CDI) cases, BI represented 19% of first-episode CDI isolates in 2013-2015. Two additional REA group strains accounted for 31% of isolates (Y, 16%; DH, 12%). High-level resistance to fluoroquinolones and azithromycin was more common among BI isolates than among DH, Y, and non-BI/DH/Y isolates. Multivariable analysis revealed that BI cases were 2.47 times more likely to be associated with fluoroquinolone exposure compared to non-BI cases (95% confidence interval [CI]: 1.12-5.46). In addition, the odds of developing a CDI after third- or fourth-generation cephalosporin exposure was 2.83 times for DH cases than for non-DH cases (95% CI: 1.06-7.54). Fluoroquinolone use in the hospital decreased from 2005 to 2015 from a peak of 113 to a low of 56 antimicrobial days/1,000 patient days. In contrast, cephalosporin use increased from 42 to 81 antimicrobial days/1,000 patient days. These changes correlated with a decrease in geometric mean MIC for ciprofloxacin (61.03 to 42.65 mg/L, P = 0.02) and an increase in geometric mean MIC for ceftriaxone (40.87 to 86.14 mg/L, P < 0.01) among BI isolates. The BI strain remained resistant to fluoroquinolones, but an overall decrease in fluoroquinolone use and increase in cephalosporin use were associated with a decrease in the prevalence of BI, an increased diversity of C. difficile strain types, and the emergence of strains DH and Y.

A Novel Truncated CHAP Modular Endolysin, CHAPSAP26-161, That Lyses Staphylococcus aureus, Acinetobacter baumannii, and Clostridioides difficile, and Exhibits Therapeutic Effects in a Mouse Model of A. baumannii Infection.

Development of novel antibacterial agents is imperative due to the increasing threat of antibiotic-resistant pathogens. This study aimed to develop the enhanced antibacterial activity and in-vivo efficacy of a novel truncated endolysin, CHAPSAP26-161, derived from the endolysin LysSAP26, against multidrug-resistant bacteria. CHAPSAP26-161 exhibited higher protein purification efficiency in E. coli and antibacterial activity than LysSAP26. Moreover, CHAPSAP26-161 showed the higher lytic activity against A. baumannii with minimal bactericidal concentrations (MBCs) of 5-10 µg/ml, followed by Staphylococcus aureus with MBCs of 10-25 µg/ml. Interestingly, CHAPSAP26-161 could lyse anaerobic bacteria, such as Clostridioides difficile, with MBCs of 25-50 µg/ml. At pH 4-8 and temperatures of 4°C-45°C, CHAPSAP26-161 maintained antibacterial activity without remarkable difference. The lytic activity of CHAPSAP26-161 was increased with Zn2+. In vivo tests demonstrated the therapeutic effects of CHAPSAP26-161 in murine systemic A. baumannii infection model. In conclusion, CHAPSAP26-161, a truncated endolysin that retains only the CHAP domain from LysSAP26, demonstrated enhanced protein purification efficiency and antibacterial activity compared to LysSAP26. It further displayed broad-spectrum antibacterial effects against S. aureus, A. baumannii, and C. difficile. Our in vitro and in-vivo results of CHAPSAP26-161 highlights its promise as an innovative therapeutic option against those bacteria with multiple antibiotic resistance.