Penicillin Binding Protein Substitutions Cooccur with Fluoroquinolone Resistance in Epidemic Lineages of Multidrug-Resistant Clostridioides difficile.

Clostridioides difficile remains a key cause of healthcare-associated infection, with multidrug-resistant (MDR) lineages causing high-mortality (≥20%) outbreaks. Cephalosporin treatment is a long-established risk factor, and antimicrobial stewardship is a key control. A mechanism underlying raised cephalosporin MICs has not been identified in C. difficile, but among other species, this is often acquired via amino acid substitutions in cell wall transpeptidases (penicillin binding proteins [PBPs]). Here, we investigated five C. difficile transpeptidases (PBP1 to PBP5) for recent substitutions, associated cephalosporin MICs, and co-occurrence with fluoroquinolone resistance. Previously published genome assemblies (n = 7,096) were obtained, representing 16 geographically widespread lineages, including healthcare-associated ST1(027). Recent amino acid substitutions were found within PBP1 (n = 50) and PBP3 (n = 48), ranging from 1 to 10 substitutions per genome. ß-Lactam MICs were measured for closely related pairs of wild-type and PBP-substituted isolates separated by 20 to 273 single nucleotide polymorphisms (SNPs). Recombination-corrected phylogenies were constructed to date substitution acquisition. Key substitutions such as PBP3 V497L and PBP1 T674I/N/V emerged independently across multiple lineages. They were associated with extremely high cephalosporin MICs; 1 to 4 doubling dilutions >wild-type, up to 1,506 µg/mL. Substitution patterns varied by lineage and clade, showed geographic structure, and occurred post-1990, coincident with the gyrA and/or gyrB substitutions conferring fluoroquinolone resistance. In conclusion, recent PBP1 and PBP3 substitutions are associated with raised cephalosporin MICs in C. difficile. Their co-occurrence with fluoroquinolone resistance hinders attempts to understand the relative importance of these drugs in the dissemination of epidemic lineages. Further controlled studies of cephalosporin and fluoroquinolone stewardship are needed to determine their relative effectiveness in outbreak control. IMPORTANCE Fluoroquinolone and cephalosporin use in healthcare settings has triggered outbreaks of high-mortality, multidrug-resistant C. difficile infection. Here, we identify a mechanism associated with raised cephalosporin MICs in C. difficile comprising amino acid substitutions in two cell wall transpeptidase enzymes (penicillin binding proteins). The higher the number of substitutions, the greater the impact on phenotype. Dated phylogenies revealed that substitutions associated with raised cephalosporin and fluoroquinolone MICs were co-acquired immediately before clinically important outbreak strains emerged. PBP substitutions were geographically structured within genetic lineages, suggesting adaptation to local antimicrobial prescribing. Antimicrobial stewardship of cephalosporins and fluoroquinolones is an effective means of C. difficile outbreak control. Genetic changes associated with raised MIC may impart a "fitness cost" after antibiotic withdrawal. Our study therefore identifies a mechanism that may explain the contribution of cephalosporin stewardship to resolving outbreak conditions. However, due to the co-occurrence of raised cephalosporin MICs and fluoroquinolone resistance, further work is needed to determine the relative importance of each.

Critical Care Nurses' Experiences of Caring for Patients With COVID-19: Results of a Thematic Analysis.

BACKGROUND: The COVID-19 pandemic has challenged health care professionals, especially those working in intensive care units (ICUs). OBJECTIVES: To explore critical care nurses' experiences with and perceptions of the COVID-19 pandemic during the early phases of the pandemic. METHODS: Data were from national surveys conducted during March and April 2020 to assess ICU providers' perceptions of the initial phases of the pandemic. A total of 831 responses from nurses to open-ended questions were examined by using thematic analysis. The questions assessed potentially limited resources in the ICU, adequacy of staffing, and measures used to reduce the possibility of spreading COVID-19 to family members. RESULTS: Overarching themes concerned access to equipment and preventive measures taken to reduce exposure to the virus. These themes included "sheltering the patient when I don't have enough" and "protecting those I love when I am a vector of transmission." Subthemes for the first overarching theme included not having enough personal protective equipment, not enough staff and not enough properly trained staff, and not enough institutional support. Subthemes for the second overarching theme included "isolating myself from everyone I care about" and "isolating everything I touch from everyone I care about." CONCLUSIONS: This thematic analysis identified several concerns of ICU nurses related to caring for patients in the initial phases of the COVID-19 pandemic. Ensuring adequate supplies, staffing, and administrative and emotional support are provided to frontline health care providers during the ongoing pandemic remains essential.

Biofilms harbour Clostridioides difficile, serving as a reservoir for recurrent infection.

C. difficile infection (CDI) is a worldwide healthcare problem with ~30% of cases failing primary therapy, placing a burden on healthcare systems and increasing patient morbidity. We have little understanding of why these therapies fail. Here, we use a clinically validated in vitro gut model to assess the contribution of biofilms towards recurrent disease and to investigate biofilm microbiota-C. difficile interactions. Initial experiments show that C. difficile cells became associated with the colonic biofilm microbiota and are not depleted by vancomycin or faecal microbiota transplant therapies. We observe that transferring biofilm encased C. difficile cells into a C. difficile naïve but CDI susceptible model induces CDI. Members of the biofilm community can impact C. difficile biofilm formation by acting either antagonistically or synergistically. We highlight the importance of biofilms as a reservoir for C. difficile, which can be a cause for recurrent infections.

Evidence-based practice center network and health technology assessment in the United States: bridging the cultural gap.

OBJECTIVES: The purpose of this study was to identify the Evidence-Based Practice Center (EPC) network participants' perceptions of the characteristics of the EPC process and the relationship of the process to the success of EPC reports. METHODS: Semistructured interviews were conducted with the three groups involved in the EPC: EPC staff, Agency for Healthcare Research and Quality (AHRQ) staff, and representatives of partner organizations. RESULTS: The analysis of the coded transcripts revealed three related major themes, which form the conceptual basis for the interpretation presented here: the definition of a successful report, the determinants of a successful report, and the role of AHRQ in the process. CONCLUSIONS: A successful report is a report that is used. The ultimate success of the core health technology assessment objective, moving from research to policy, depends on balancing two values: excellence and relevance. Our findings are consistent with the "two communities thesis," which postulates the existence of two camps that confer different values to excellence and relevance, with resulting tension. A promising model for approaching this tension is integration or collaboration, which requires linking researchers and policy makers, promoting productive dialogues about the formulation and timing of analysis, and early consideration of how the resulting analysis will be used. This effort suggests that actively blurring the frontiers between these two groups will enhance their interaction. Furthermore, enhancing the role of the AHRQ as scientific broker will maximize the potential of the EPC network.

Dissemination of Evidence-based Practice Center reports.

The Evidence-based Practice Center (EPC) program within the Agency for Healthcare Research and Quality (AHRQ) provides detailed evidence reports for partner organizations that they can translate into activities that improve patient care. A review of these dissemination activities provides a rich opportunity to understand how to create more successful linkages between best evidence and best practice. On the basis of interviews with EPC directors, AHRQ staff, and representatives of public and private users of EPC reports, we summarize the variety of efforts to disseminate the work of the EPCs. We also identify a case example of a successful dissemination of an EPC report. Experience to date reinforces the importance of creating close ties between researchers and the policymakers, clinicians, and other decision makers who use EPC evidence reports; developing a conceptual framework to guide the process; and establishing the resource foundation for the entire effort.