Antimicrobial-resistant Enterobacterales colonization in people with HIV.

Background: People with HIV (PWH) may be at increased risk for MDR Enterobacterales (MDR-E) infection or colonization, relative to individuals without HIV, due to a greater burden of comorbidities as well as HIV-related intestinal inflammation and microbiota alterations. Objectives: To characterize antibiotic susceptibility of enteric Enterobacterales and risk factors for antimicrobial-resistant bacterial infections in a sample of PWH attending routine clinic visits. Methods: Participants provided self-administered rectal swabs and completed questionnaires regarding healthcare, travel and occupational exposures for the prior 12 months. Rectal samples were processed to identify Enterobacterales species, and susceptibility testing was performed. Results: Among 82 participants, 110 Enterobacterales isolates were obtained. Non-susceptibility was common for penicillins, sulphonamides and first-generation cephalosporins. MDR-E was present in 20% of participants. HIV-related characteristics, including current or nadir CD4 cell count, viral suppression, or AIDS-defining clinical conditions, were not associated with MDR-E. Conclusions: MDR-E colonization is common in this population of PWH. Further research evaluating risk factors for MDR-E in PWH may inform infection prevention approaches to better protect at-risk populations from these difficult-to-treat infections.

A Randomized Clinical Trial Comparing the Efficacy and Safety of 2% Versus 4% Chlorohexidine Gluconate for Surgical Preparation of the Vagina.

IMPORTANCE: There have been no studies comparing 2% and 4% chlorhexidine gluconate (CHX) for vaginal surgical site preparation despite both commonly being used. OBJECTIVES: The primary objective was to assess the noninferiority of 2% CHX versus 4% CHX to reduce bacterial contamination rates at 60 minutes after surgical preparation of the vagina. Secondary objectives were to assess differences in colony-forming units and the sensation of postoperative vaginal burning and pain. STUDY DESIGN: This is a single-blinded randomized controlled trial of women who underwent vaginal prolapse surgery. Study participants were randomized into 2 groups: 2% CHX versus 4% CHX. Two vaginal bacterial cultures were collected: (1) preoperatively before vaginal preparation and (2) intraoperatively at 60 minutes. A questionnaire on vaginal pain and burning was administered preoperatively and postoperatively. For our sample size, assuming that 2% CHX would have double the contamination rate of 4% CHX, 26 participants were needed per group to demonstrate noninferiority. RESULTS: Sixty-one women participated in the study. There were no differences in baseline demographics, length of surgery, or surgical procedures. For our primary outcome, the postpreparation contamination rates were 7% for 2% CHX versus 10% for 4% CHX, with a difference of 3% ( P = 0.52). This difference did meet the criteria for noninferiority. Secondary outcomes were not different between groups. CONCLUSIONS: Two percent CHX is noninferior to 4% CHX in reducing vaginal bacterial contamination at 60 minutes after vaginal surgical site preparation, with low rates of postpreparation contamination and vaginal discomfort.

Lysis-Hi-C as a method to study polymicrobial communities and eDNA.

Microbes interact in natural communities in a spatially structured manner, particularly in biofilms and polymicrobial infections. While next generation sequencing approaches provide powerful insights into diversity, metabolic capacity, and mutational profiles of these communities, they generally fail to recover in situ spatial proximity between distinct genotypes in the interactome. Hi-C is a promising method that has assisted in analysing complex microbiomes, by creating chromatin cross-links in cells, that aid in identifying adjacent DNA, to improve de novo assembly. This study explored a modified Hi-C approach involving an initial lysis phase prior to DNA cross-linking, to test whether adjacent cell chromatin can be cross-linked, anticipating that this could provide a new avenue for study of spatial-mutational dynamics in structured microbial communities. An artificial polymicrobial mixture of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli was lysed for 1-18 h, then prepared for Hi-C. A murine biofilm infection model was treated with sonication, mechanical lysis, or chemical lysis before Hi-C. Bioinformatic analyses of resulting Hi-C interspecies chromatin links showed that while microbial species differed from one another, generally lysis significantly increased links between species and increased the distance of Hi-C links within species, while also increasing novel plasmid-chromosome links. The success of this modified lysis-Hi-C protocol in creating extracellular DNA links is a promising first step toward a new lysis-Hi-C based method to recover genotypic microgeography in polymicrobial communities, with potential future applications in diseases with localized resistance, such as cystic fibrosis lung infections and chronic diabetic ulcers.