Difficile Colonization Research Articles

O19. Mother-offspring association: impact of sow’s diet on Clostridioides difficile colonisation in suckling piglets and colostrum potential against toxins in IPEC-J2

O19. Mother-offspring association: impact of sow’s diet on Clostridioides difficile colonisation in suckling piglets and colostrum potential against toxins in IPEC-J2

Notes from the Field: Escherichia coli O157:H7 Outbreak in Children with Clostridioides difficile Colonization Associated with an Improperly Treated Swimming Pool - Pennsylvania, June 2021.

Notes from the Field: Escherichia coli O157:H7 Outbreak in Children with Clostridioides difficile Colonization Associated with an Improperly Treated Swimming Pool - Pennsylvania, June 2021.

Clostridioides difficile: A diagnostic intervention

Background:Clostridioides difficile infection (CDI) is a leading cause of healthcare-associated infection and is associated with increased morbidity and mortality. Multiple strategies have been implemented to optimize the diagnostic accuracy of CDI testing algorithms. However, overdiagnosis of C. difficile colonization remains a challenge especially in the era of highly sensitive Nucleic acid amplification testing (NAAT). We implemented 2 interventions to reduce the rates of inappropriate C. difficile orders and tests. Methods: We performed a quasi-experimental retrospective study to examine the rates of all inpatient C. difficile test orders and results relative to 2 interventions between January 2018 and February 2021. We defined 3 periods: preintervention, after the first intervention, and after the second intervention. The first intervention, implemented May 2019, was a clinical decision support system (CDSS) tool to guide clinicians to order testing only if CDI criteria were met. The second intervention, implemented July 2020, was the requirement of mandatory antimicrobial team approval of PCR reflex testing for indeterminate toxin or antigen test results. This intervention included a discussion between clinicians and members of stewardship team prior to approval. To evaluate the impact of interventions on ordering appropriateness, chart review was conducted on a random subsample of 100 orders from each period. Hospital-onset CDI (HO-CDI) was calculated using CDC criteria. Results: In total, 3,004 C. difficile test orders were placed during the study period. The rates of reportable HO-CDI were significantly reduced by 57.1% (P = .003). We detected a significant reduction in the number of tests ordered over time from 11.6 to 7.51 per 1,000 patient days. (p Conclusions: CDSS tools target patients at high pretest probability of CDI. The restriction of PCR-reflex testing to the antimicrobial stewardship team is a novel effective measure to minimize the misdiagnosis of CDI. The incorporation of multiple strategies is necessary to improve the diagnostic accuracy of C. difficile testing.Funding: NoneDisclosures: None

Clostridioides difficile surface layer protein triggered inflammasome activation is mediated by membrane lipid raft

Clostridioides difficile is the leading cause of nosocomial infectious diarrhea, with clinical symptoms ranging from mild diarrhea to pseudomembranous colitis and toxic megacolon. Despite the use of vancomycin and fidaxomicin as standard drugs for the treatment of C. difficileinfection (CDI), clinical relapse rates remain high. Therefore, new alternative therapeutics to treat CDI are urgently required. Surface layer proteins (SLPs) are the most abundant proteins in the C. difficile cell wall, suggesting that they might involve in immune recognition. Here, we found SLPs as well as C. difficile induced inflammasome activation. In addition, the cholesterol‐rich microdomains, lipid rafts, on the cell membrane are thought to be crucial for bacterial adhesion and signal transduction. We demonstrated that lipid rafts participated in C. difficile SLPs binding to the cell membrane. Furthermore, both binding ability and inflammasome activation induced by SLP were abrogated with membrane cholesterol depletion by methyl‐β‐cyclodextrin (MβCD). The coalescence of SLPs in the cholesterol‐rich microdomains was confirmed in C. difficile‐infected cells. Our results demonstrate that SLPs recruit the lipid rafts, which may be a key step for C. difficile colonization and inducing inflammasome activation.

Improving Stewardship of Clostridioides difficile Testing with EMR and Provider Phone Calls.

IntroductionModern laboratory techniques cannot differentiate between Clostridium difficile colonization and infection; therefore, testing must be indicated clinically. To reduce hospital-onset of C. difficile infections (HO-CDI), Ascension Via Christi Hospitals (AVCH) in Wichita intervened in three stages by introducing: 1) a C. diflcile testing algorithm; 2) an electronic medical record (EMR)-based decision support system to enforce said algorithm; and 3) phone calls from the infection prevention department to providers to discontinue tests not collected within 24 hours of the order. The goal of this study was to determine if these interventions improved the HO-CDI rate.MethodsAt AVCH, the three study periods were compared: baseline with algorithm training only, the EMR intervention, and the EMR intervention with additional phone calls (EMR with phone calls). Data were abstracted from the hospital EMR.ResultsA total of 311 charts were reviewed. Adherence to the algorithm increased from 34% at baseline to 52% after the EMR intervention (p = 0.010). During the EMR with phone calls period, more tests were discontinued (87%; n = 39) compared to baseline (54%; n = 15) and EMR (54%; n = 15; p = 0.003). The HO-CDI rate ranged from 8.5 cases per 10,000 patient-days at baseline, to 7.9 during EMR, to 4.0 during EMR with phone calls (p = 0.007).ConclusionsThe EMR and EMR with phone call interventions were associated with a significant decrease in the HO-CDI rate and an increase in provider adherence to the algorithm.

Evaluating Cefoperazone-Induced Gut Metabolic Functional Changes in MR1-Deficient Mice.

Mucosal-associated invariant T cells are activated following the recognition of bacterial antigens presented by the major histocompatibility complex class I-related molecule (MR1). Previous metagenomics data showed that MR1−/− knock-out (KO) mice had distinct microbiota and displayed a resistance to Clostridioides difficile (CDI) colonization vs. wild-type (WT) mice. In the present study, LC/MS-based untargeted metabolomics are applied to evaluate the changes in metabolic activities, in accordance with the changes in gut microbiota caused by cefoperazone (Cef) treatment. Adult C57Bl/6J WT and MR1−/− KO mice were given sterile drinking water or spiked with 0.5 mg/mL Cef ad libitum for five days. Fecal pellets were collected daily, and both small intestinal and cecal contents were harvested at sacrifice. The PLS-DA score plots of the metabolomic data indicate that the microbiota is relatively less disturbed by Cef treatment in KO mice, which is consistent with the metagenomics data. The most noticeable differences in the metabolome of KO and WT mice were the increases in carbohydrates in the WT mice, but not in the KO mice. Metabolic functional biomarkers were identified through the correlation analysis of gamma-aminobutyric acid (GABA) and riboflavin. These detected metabolic functional biomarkers could provide information complementary to metagenomics data.

Environmentally Acquired Bacillus and Their Role in C. difficile Colonization Resistance.

Clostridioides difficile is an environmentally acquired, anaerobic, spore-forming bacterium which ordinarily causes disease following antibiotic-mediated dysbiosis of the intestinal microbiota. Although much is understood regarding the life cycle of C. difficile, the fate of C. difficile spores upon ingestion remains unclear, and the underlying factors that predispose an individual to colonization and subsequent development of C. difficile infection (CDI) are not fully understood. Here, we show that Bacillus, a ubiquitous and environmentally acquired, spore-forming bacterium is associated with colonization resistance to C. difficile. Using animal models, we first provide evidence that animals housed under conditions that mimic reduced environmental exposure have an increased susceptibility to CDI, correlating with a loss in Bacillus. Lipopeptide micelles (~10 nm) produced by some Bacilli isolated from the gastro-intestinal (GI)-tract and shown to have potent inhibitory activity to C. difficile have recently been reported. We show here that these micelles, that we refer to as heterogenous lipopeptide lytic micelles (HELMs), act synergistically with components present in the small intestine to augment inhibitory activity against C. difficile. Finally, we show that provision of HELM-producing Bacillus to microbiota-depleted animals suppresses C. difficile colonization thereby demonstrating the significant role played by Bacillus in colonization resistance. In the wider context, our study further demonstrates the importance of environmental microbes on susceptibility to pathogen colonization.

Fiber Composition in Sows\u2019 Diets Modifies Clostridioides difficile Colonization in Their Offspring

Dietary fiber has a potential to modulate the gut microbiota in sows. We hypothesized that a maternal diet rich in either high- or low-fermentable fiber during gestation and lactation influences Clostridioides difficile gut colonization in suckling piglets. Twenty sows were fed gestation and lactation diets enriched with either high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibers. C. difficile, toxin B (TcdB), fecal score, microbial abundance (16S-rDNA sequencing) and metabolites were measured in the feces from the sows and their piglets. C. difficile concentration was higher in piglets from the sows fed LNC than SBP along the study (P ≤ 0.05). Higher prevalence of C. difficile was noted in three-week-old piglets from sows fed LNC vs. SBP (45% vs. 0%, P = 0.001). TcdB prevalence was higher in six-day-old piglets from the sows fed LNC vs. SBP (60% vs. 17%, P = 0.009). In sows, fecal microbial metabolites were higher in SBP than LNC, while C. difficile concentration showed no difference. Higher microbial diversity Shannon index was noted in sows from SBP vs. LNC one week before parturition and at the parturition (P ≤ 0.05). Piglets from SBP vs. LNC tended to have higher microbial diversity Shannon index at two and three weeks of age. Diets enriched with high-fermentable fiber compared to low-fermentable fiber in sows reduced C. difficile colonization in their piglets. Susceptibility to colonization by C. difficile in neonatal piglets can be modulated by the sows’ diet, supporting the hypothesis of the early microbial programming in the offspring and the importance of the sow-piglet couple.

Health care associated Clostridioides difficile infection and colonization in patients admitted at tertiary care hospital Pakistan.

To evaluate the epidemiology of clostridioides difficile infections and colonisation in a tertiary-care setting. The cross-sectional study was conducted at the Combined Military Hospital, Rawalpindi, Pakistan, from June 1, 2017, to October 31, 2019, and comprised adult patients admitted in high-risk units of the hospital for any disease experiencing watery stools after 48 hours of hospital admission and passing more than 3 stools per day with no other recognised aetiology. Stool samples of the participants, diagnosed with antibiotic associated diarrhoea, were submitted for glutamate dehydrogenase antigen assay and clostridioides toxin A/B assay detected by enzyme-linked immunosorbent assay and clostridioides difficile toxin gene detection by polymerase chain reaction. Clostridium difficile-associated diarrhoea was diagnosed by a positive toxin assay or polymerase chain reaction. Data was analysed using SPSS25. Of the 715 subjects, 322(45%) were males and 393(55%) were females. The overall mean age was 56.64±8.57 years, and 488(68.3%) were aged <60 years, while 227(31.7%) were aged >60 years. The incidence of clostridioides difficile-associated diarrhoea was found in 10(1.4%) patients and was highest in oncology unit 3(4.3%). No positive case was detected from the high dependency unit and the surgical ward. All the10(1.4%) positive cases were on >2 antibiotics with a combination of oral vancomycin and intravenous metronidazole. Mortality rate was significantly higher in the positive cases compared to those with clostridioides difficile colonisation (p<0.05). The incidence of clostridioides difficile-associated diarrhoea was found to be low.

Disordered Intestinal Microbial Communities During Clostridioides difficile Colonization and Subsequent Infection of Hepatic Cirrhosis Patients in a Tertiary Care Hospital in China.

Patients with hepatic cirrhosis are more susceptible to Clostridioides difficile infection (CDI) and colonization with Clostridioides difficile (C. difficile). Asymptomatic C. difficile colonization is thought to predispose to subsequent CDI. However, the dynamic gut microbiota changes remain unclear. In this study, we used 16S rRNA gene sequencing to longitudinally monitor alterations in the intestinal microbiota of 22 hepatic cirrhosis patients with toxigenic C. difficile colonization at admission (pre-CDI) and developed CDI during hospitalization, subdivided into pre-CDI and CDI. 21 hospitalized cirrhotic patients without C. difficile colonization served as controls (HC). Compared with HC, pre-CDI and CDI samples had significantly decreased microbial richness and diversity, a significantly higher relative abundance of opportunistic pathogen Enterococcus, and a lower relative abundance of beneficial symbionts, such as Faecalibacterium, Dorea, and Roseburia. Three biomarkers showed high accuracy for distinguishing pre-CDI samples from HC with an area under the curve (AUC) up to 0.81. In conclusion, our study explored the changes of the gut microbiome before and after CDI. The gut microbial richness as well as diversity in CDI patients were notably reduced, relative to controls. Imbalance of the intestinal flora may be related to the risk for development of CDI. Identifying key members of the gut microbiota and illustrating their roles and mechanisms of action in CDI development are important avenues for future research.

"PREVENTIVE MEASURES FOR CLOSTRIDIOIDES DIFFICILE INFECTIONS IN HOSPITAL SETTINGS: A LITERATURE REVIEW OF RECOMMENDATIONS AND NOVEL TARGETED STRATEGIES"

"Introduction: Clostridioides difficile infections (CDIs) are one of the most frequent hospital- acquired infections. The microorganism is considered the leading cause of acute diarrheal syndrome after the use of antibiotics, in Romania. Objective: The main objective is to provide a comprehensive review summarizing existing evidence regarding how CDIs can be prevented. Methods: We screened PubMed, PubMed Central (PMC), ScienceDirect, and Google Scholar, clinical trials in different phases, and several national and international guidelines on the subject of prevention of C. difficile infections, using specific keywords. Results: We divided the recommendations into the following categories: good practice, strong, weak, and no recommendations, while novel strategies are detailed separately. The newly available treatment options have been analyzed as well as the ongoing efforts to obtain novel therapies, such as synthetic biologics that curb C. difficile colonization and proliferation, the association between ribaxamase (a poorly absorbable beta-lactamase) and parenteral broad-spectrum antibiotics, antisense molecules with potent anti-difficile activity or antibody-based therapeutics. Conclusions: At the time of submission, there is no globally accepted guideline in regard to the management of patients with Clostridioides difficile infections. Conventional strategies have lowered the incidence of CDIs but seem insufficient to eradicate hospital-acquired C. difficile infections. The challenge of CDIs has pushed researchers towards novel approaches, which may be the solution for many difficult-to-treat infections. Keywords: Clostridioides difficile, CDI, ribotype 027, post-antibiotic infection, pseudomembranous colitis, toxic megacolon"

The development of live biotherapeutics against Clostridioides difficile infection towards reconstituting gut microbiota

ABSTRACT Clostridioides difficile is the most prevalent pathogen of nosocomial diarrhea. In the United States, over 450,000 cases of C. difficile infection (CDI), responsible for more than 29,000 deaths, are reported annually in recent years. Because of the emergence of hypervirulent strains and strains less susceptible to vancomycin and fidaxomicin, new therapeutics other than antibiotics are urgently needed. The gut microbiome serves as one of the first-line defenses against C. difficile colonization. The use of antibiotics causes gut microbiota dysbiosis and shifts the status from colonization resistance to infection. Hence, novel CDI biotherapeutics capable of reconstituting normal gut microbiota have become a focus of drug development in this field.

High rate of Clostridioides difficile colonization in patients admitted to intensive care: A prospective cohort study

Here, we evaluated the frequency of C. difficile colonization and its impact on clinical outcomes in patients admitted to intensive care units in Brazil. From ninety-two patients screened 16 (17.3%) were colonized by C. difficile. Colonized patients had higher Simplified Acute Physiology Score III (SAPS III), however there was no association between C. difficile colonization with diarrhea or mortality. The C. difficile strains sequenced belonged to clade 1 and presented high vancomycin-resistant rates.

Clostridioides difficile colonization among very young children in resource-limited settings

ObjectivesTo describe the epidemiology and risk factors for Clostridioides difficile (C. difficile) colonization among young children in eight low-resource settings. MethodsWe tested 41 354 monthly non-diarrhoeal and diarrhoeal stools for C. difficile toxin genes (TcdA and TcdB) using quantitative PCR (qPCR) in 1715 children from birth to age two years in a multisite birth cohort study. We estimated the prevalence, cumulative incidence, and seasonality of C. difficile colonization and investigated the associations of C. difficile detection with risk factors of infection, markers of enteropathy, and growth. ResultsThe prevalence of C. difficile detection was lower in diarrhoeal (2.2%; n = 151/6731) compared to non-diarrhoeal stools (6.1%; n = 2106/34 623). By 24 months of age, the cumulative incidence of C. difficile varied widely by site, with 17.9% (n = 44; Pakistan) to 76.3% (n = 148; Peru) of children having at least one positive stool. Only Bangladesh and Pakistan had seasonal differences in C. difficile detection. Female sex (adjusted risk ratio (aRR): 1.18; 95% CI: 1.02–1.35), cephalosporin use in the past 15 days (aRR: 1.73; 95% CI: 1.39–2.16), and treated water (aRR: 1.24; 95% CI: 1.02–1.50) were risk factors for C. difficile positivity. The presence of C. difficile was significantly associated with elevated faecal myeloperoxidase, neopterin, and α-1-antitrypsin, but no associations were found between C. difficile and child growth at 24 months of age. DiscussionC. difficile colonization among children ages 0–2 years was variable across low-resource settings. Significant elevation of intestinal inflammation and barrier disruption markers associated with C. difficile detection suggests a subclinical impact of colonization.

Multi-omics investigation of Clostridioides difficile-colonized patients reveals pathogen and commensal correlates of C. difficile pathogenesis.

Clostridioides difficile infection (CDI) imposes a substantial burden on the health care system in the United States. Understanding the biological basis for the spectrum of C. difficile-related disease manifestations is imperative to improving treatment and prevention of CDI. Here, we investigate the correlates of asymptomatic C. difficile colonization using a multi-omics approach. We compared the fecal microbiome and metabolome profiles of patients with CDI versus asymptomatically colonized patients, integrating clinical and pathogen factors into our analysis. We found that CDI patients were more likely to be colonized by strains with the binary toxin (CDT) locus or strains of ribotype 027, which are often hypervirulent. We find that microbiomes of asymptomatically colonized patients are significantly enriched for species in the class Clostridia relative to those of symptomatic patients. Relative to CDI microbiomes, asymptomatically colonized patient microbiomes were enriched with sucrose degradation pathways encoded by commensal Clostridia, in addition to glycoside hydrolases putatively involved in starch and sucrose degradation. Fecal metabolomics corroborates the carbohydrate degradation signature: we identify carbohydrate compounds enriched in asymptomatically colonized patients relative to CDI patients. Further, we reveal that across C. difficile isolates, the carbohydrates sucrose, rhamnose, and lactulose do not serve as robust growth substrates in vitro, consistent with their enriched detection in our metagenomic and metabolite profiling of asymptomatically colonized individuals. We conclude that pathogen genetic variation may be strongly related to disease outcome. More interestingly, we hypothesize that in asymptomatically colonized individuals, carbohydrate metabolism by other commensal Clostridia may prevent CDI by inhibiting C. difficile proliferation. These insights into C. difficile colonization and putative commensal competition suggest novel avenues to develop probiotic or prebiotic therapeutics against CDI.

KLEBSIELLA PNEUMONIAE IN THE COLONIC MUCUS LAYER INFLUENCESCLOSTRIDIODES DIFFICILE PATHOGENESIS

Abstract BACKGROUND Clostridoides difficile is an intestinal pathogen responsible for 500,000 infections and 30,000 deaths annually in the US. Alarmingly, C. difficile infection is increased in patients with inflammatory bowel disease (IBD). When C. difficile infection is superimposed on colitis, it synergistically worsens both conditions. C. difficile infection is initiated by disruption of the gut microbiota; and it is well appreciated that IBD patients already have an altered fecal and mucus-associated microbiota. At present, it is not fully understood how gut microbes, particularly microbes found in IBD, influence C. difficile. Using stool-seeded bioreactors with mucus-coated inserts, we identified Klebsiella pneumoniae in the mucus-associated microbiota with C. difficile. K. pneumoniae is present at increased levels in IBD patients and we hypothesized that K. pneumoniae may promote C. difficile intestinal colonization. METHODS &amp; RESULTS To test this hypothesis, we cultured 12 strains of K. pneumoniae with four ribotypes of C. difficile in a fully defined bacteria media (ZMB1). Growth curve analysis of 24 hour cultures revealed that cell-free supernatant from all K. pneumoniae strains enhanced the growth of all C. difficile strains, suggesting that K. pneumoniae could produce metabolites that enhanced C. difficile growth. Importantly, C. difficile grew well with K. pneumoniae bacteria and both bacteria were present in the cultures by gram stain. Non-targeted metabolomics revealed that the presence of K. pneumonia shifted the metabolism of C. difficile away from carbohydrate utilization and toward alternative fuel sources. K. pneumoniae is well known for its ability to create biofilms. To examine biofilm production, we grew C. difficile alone or with K. pneumoniae and examined biofilm by crystal violet staining. Although biofilms were nominally enhanced with K. pneumoniae compared to C. difficile alone, these biofilms were significantly lower than K. pneumoniae alone; indicating that biofilm synthesis is not a significant component of C. difficile-Klebsiella interactions. Finally, we examined how K. pneumoniae impacts C. difficile infection in vitro using colonic organoids by RNA sequencing. Sequencing revealed significantly elevated pro-inflammatory pathways when C. difficile and K. pneumonia were incubated together than either pathogen alone. CONCLUSIONS These results suggest that K. pneumoniae can influence C. difficile metabolism and exacerbate inflammation.

Probiotic colonization dynamics after oral consumption of VSL#3® by antibiotic-treated mice.

Background: The ability of probiotic strains to provide health benefits to the host partially hinges on the survival of gastrointestinal passage and temporary colonization of the digestive tract. This study aims to investigate the colonization profile of individual probiotic strains comprising the commercial product VSL#3® and determine their impact on the host intestinal microbiota. Methods: Using a cefoperazone-treated mouse model of antibiotic treatment, we investigated the impact of oral gavage with ~108 CFU commercial VSL#3® product on the intestinal microbiota using 16S-based amplicon sequencing over 7 days. Results: Results showed that probiotic strains in the formulation were detected in treated murine fecal samples, with early colonization by Streptococcus thermophilus and Lactiplantibacillus plantarum subsp. plantarum, and late colonization by Lacticaseibacillus paracasei subsp. paracasei, Bifidobacterium breve and Bifidobacterium animalis subsp. lactis. Overall, VSL#3® consumption is associated with increased alpha diversity in the cecal microbial community, which is important in the context of antibiotic consumption. Probiotic supplementation resulted in an expansion of Proteobacteria, Bacteroidetes, and Actinobacteria, especially Bifidobacteriaceae and Lachnospiraceae, which are associated with Clostridioides difficile resistance in the murine gut. Conclusion: This study illustrates the need for determining the ability of probiotics to colonize the host and impact the gut microbiota, and suggests that multiple doses may be warranted for extended transient colonization. In addition, follow-up studies should determine whether VSL#3® can provide resistance against C. difficile colonization and disease in a mouse model.

Gut microbiota features associated with Clostridioides difficilecolonization in dairy calves.

Diarrheal disease, a major cause of morbidity and mortality in dairy calves, is strongly associated with the health and composition of the gut microbiota. Clostridioides difficile is an opportunistic pathogen that proliferates and can produce enterotoxins when the host experiences gut dysbiosis. However, even asymptomatic colonization with C. difficile can be associated with differing degrees of microbiota disruption in a range of species, including people, swine, and dogs. Little is known about the interaction between C. difficile and the gut microbiota in dairy calves. In this study, we sought to define microbial features associated with C. difficile colonization in pre-weaned dairy calves less than 2 weeks of age. We characterized the fecal microbiota of 80 calves from 23 different farms using 16S rRNA sequencing and compared the microbiota of C. difficile-positive (n = 24) and C. difficile-negative calves (n = 56). Farm appeared to be the greatest source of variability in the gut microbiota. When controlling for calf age, diet, and farm location, there was no significant difference in Shannon alpha diversity (P = 0.50) or in weighted UniFrac beta diversity (P = 0.19) between C. difficile-positive and-negative calves. However, there was a significant difference in beta diversity as assessed using Bray-Curtiss diversity (P = 0.0077), and C. difficile-positive calves had significantly increased levels of Ruminococcus (gnavus group) (Adj. P = 0.052), Lachnoclostridium (Adj. P = 0.060), Butyricicoccus (Adj. P = 0.060), and Clostridium sensu stricto 2 compared to C. difficile-negative calves. Additionally, C. difficile-positive calves had fewer microbial co-occurrences than C. difficile-negative calves, indicating reduced bacterial synergies. Thus, while C. difficile colonization alone is not associated with dysbiosis and is therefore unlikely to result in an increased likelihood of diarrhea in dairy calves, it may be associated with a more disrupted microbiota.

134. Impact of an Antibiotic Stewardship Treatment and Management Algorithm for Liver Abscesses

BackgroundAntibiotic prescribing for pyogenic liver abscess(es) (PLA) is highly variable with literature primarily aimed at assessing surgical intervention with a scarcity of data for antibiotic selection and duration of therapy. Given the lack of data, there is no clear consensus for treatment options or length of treatment. Our Antimicrobial Support Network (ASN) in collaboration with the hepatopancreatobiliary (HPB) team created a treatment and management algorithm to guide duration of therapy and antibiotic selection. MethodsA retrospective, quasi-experimental cohort study was performed at Carolinas Medical Center in hospitalized patients with PLA with an HPB and/or infectious diseases consult. The primary outcome was antipseudomonal beta-lactam days of therapy (DOT) per 1000 patient days (PD) in the pre-versus post-intervention group. Secondary outcomes included rates of treatment failure at 90 days, 90-day all-cause and abscess-related hospital readmission, C. difficile and multi-drug resistant organism (MDRO) colonization at 90 days from diagnosis, and hospital length of stay (LOS). Additional a priori subgroup analyses of duration of therapy, treatment failure, all-cause and abscess-related readmissions were also conducted based on surgical intervention. ResultsA total of 93 patients were included, 49 patients in the pre-intervention group and 44 patients in the post-intervention group. Baseline characteristics were similar between the groups. The majority of liver abscesses were unilocular and monomicrobial. Anti-pseudomonal beta-lactam DOT per 1000 PD decreased by 13.8% (507.4 versus 437.5 DOT/1000 PD). Treatment failure occurred in 30.6% of pre-intervention patients and 18.2% of post-intervention patients (p = 0.165). Patients in the post-intervention group were discharged a median of 2.4 days sooner than the pre-intervention period (12.2 days vs. 9.8 days, p = 0.159). No significant differences resulted in 90-day readmission rates or 90-day C. difficile or MDRO rates.Table 1. Primary Outcome for Patients with Pyogenic Liver Abscesses Treated Pre- and Post-Antibiotic Stewardship Algorithm Table 2. Secondary Outcomes for Patients with Pyogenic Liver Abscesses Treated Pre- and Post-Antibiotic Stewardship Algorithm ConclusionThe implementation of a PLA treatment and management algorithm led to a decrease in anti-pseudomonal beta-lactams without impacting clinical outcomes and a trend towards decreased LOS. Disclosures All Authors: No reported disclosures

Gut microbiota in burned patients with Clostridioides difficile infection

BackgroundThe survival rate of patients with severe burn is positively associated with increasing the incidence of the Clostridioides difficile (C. difficile) infection (CDI). The surviving rate of severe burn patients now has an improved but the incidence of Clostridioides difficile (C. difficile) infection (CDI) has been continues increasing during recent two decades.This study assessed the molecular typing and phenotypic characterization isolates of C. difficile in burn patients with diarrhea, as well as environmental and skin infections with C. difficile spores at a referral burn hospital in Isfahan, Iran. It mainly aimed to evaluate the dominant bacterial structure in the gut microbiome of burned subjects with and without CDI. MethodsIn general, 309 samples were collected from 189 burned patients with hospital-acquired diarrhea and 120 swabs were collected from the healthcare workers’ dominant hands, different sites of patients’ skin, and medical tools. In addition, C. difficile isolates were characterized considering the existence of antibiotic resistance and toxin genes. Clinical cultures with identification of organisms and antibiotic susceptibility were done. C. difficle isolates were then genotyped and compared to clinical outcomes. Finally, the clinical characteristics of the participants were gathered through their records, and the bacterial targets of the gut microbiome were detected using quantitative real-time polymerase chain reaction (PCR). ResultsBased on the findings, 51 C. difficile isolates were detected from 189 severe burn patients hospitalized in the hospital. Further, PCR amplification tcdB and tcdA showed 23 isolates (12.2%) as toxigenic. Overall, 18.3% (22/120) of skin and environment samples demonstrated a positive result for C. difficile colonization. A low concentration of metronidazole and vancomycin (MIC90, 0.5, and 1.2 mg/L) inhibited all toxigenic C. difficile strains. Moreover, these isolates represented the highest rates of resistance to moxifloxacin and clindamycin (MIC90, 0.5, and 1.6 mg/L). A significantly reduced abundance of Clostridium spp., Bacteroidetes, and Bifidobacterium and an increase in the quantity of Firmicutes was observed in the gastrointestinal microbiome of burn patients (P < 0.01). Burn patients with CDI showed a significant decrease in Faecalibacterium prausnitzii (F. prausnitzii) while higher Akkermansia muciniphila (A. muciniphila) loads in comparison with healthy controls (P < 0.001 and P < 0.05). Contrarily, burned cases displayed increased levels of opportunistic pathogenic bacteria including the members of Enterococcus spp. and Escherichia coli (P < 0.05). ConclusionsDespite appropriate infection control strategies in the burn intensive care unit, CDI remains prevalent in severe burn patients. Eventually, the overgrowth of A. muciniphila and the decreased abundance of F. prausnitzii in burn cases with CDI could be potential predictive microbiome biomarkers in burned patients.