Experimental genital tract infection demonstrates Neisseria gonorrhoeae MtrCDE efflux pump is not required for in vivo human infection and identifies gonococcal colonization bottleneck.

The MtrCDE efflux pump of Neisseria gonorrhoeae exports a wide range of antimicrobial compounds that the gonococcus encounters at mucosal surfaces during colonization and infection and is a known gonococcal virulence factor. Here, we evaluate the role of this efflux pump system in strain FA1090 during in vivo human male urethral infection with N. gonorrhoeae using a controlled human infection model. With the strategy of competitive infections initiated with mixtures of wild-type FA1090 and an isogenic mutant FA1090 strain that does not contain a functional MtrCDE pump, we found that the presence of the efflux pump is not required for an infection to be established in the human male urethra. This finding contrasts with previous studies of in vivo infection in the lower genital tract of female mice, which demonstrated that mutant gonococci of a different strain (FA19) lacking a functional MtrCDE pump had a significantly reduced fitness compared to their wild-type parental FA19 strain. To determine if these conflicting results are due to strain or human vs. mouse differences, we conducted a series of systematic competitive infections in female mice with the same FA1090 strains as in humans, and with FA19 strains, including mutants that do not assemble a functional MtrCDE efflux pump. Our results indicate the fitness advantage provided by the MtrCDE efflux pump during infection of mice is strain dependent. Owing to the equal fitness of the two FA1090 strains in men, our experiments also demonstrated the presence of a colonization bottleneck of N. gonorrhoeae in the human male urethra, which may open a new area of inquiry into N. gonorrhoeae infection dynamics and control. TRIAL REGISTRATION. Clinicaltrials.gov NCT03840811.

Safety and Immunogenicity of Respiratory Syncytial Virus Prefusion Maternal Vaccine Coadministered With Diphtheria-Tetanus-Pertussis Vaccine: A Phase 2 Study.

BACKGROUND: Respiratory syncytial virus (RSV) fusion protein stabilized in the prefusion conformation (RSVPreF3) was under investigation as a maternal vaccine. METHODS: This phase 2, randomized, placebo-controlled, single-dose, multicenter study enrolled healthy, nonpregnant women, randomized 1:1:1:1:1 to 5 parallel groups studying RSVPreF3 (60 or 120 µg) coadministered with diphtheria, tetanus, and acellular pertussis vaccine (dTpa) or placebo, and dTpa coadministered with placebo. Safety and humoral immune responses were assessed. An extension phase also assessed a RSVPreF3 120 µg vaccination 12-18 months after first vaccination. RESULTS: The safety profile of RSVPreF3 was unaffected by dose or dTpa coadministration. Solicited and unsolicited adverse events (AEs) were evenly distributed across study groups. Injection-site pain was higher following the second vaccination versus the first vaccination. Medically attended AEs were rare (<5% overall). Both RSVPreF3 dose levels (alone and with dTpa) were immunogenic, increasing levels of RSV-A neutralizing antibody ≥8-fold and anti-RSVPreF3 IgG antibody ≥11-fold at 1 month postvaccination, which persisted at 12-18 months postvaccination; modest 2-fold increases were observed with a second RSVPreF3 vaccination. CONCLUSIONS: This study indicates RSVPreF3 coadministration with dTpa induces robust immune responses and is well tolerated, regardless of the RSVPreF3 dose level used. CLINICAL TRIALS REGISTRATION: NCT04138056.

The Utility of Echocardiography in Pediatric Patients with Structurally Normal Hearts and Suspected Endocarditis.

The objective of this study was to evaluate the utility of transthoracic echocardiography (TTE) in children with structurally normal hearts suspected of having infective endocarditis (IE). We hypothesized that the diagnostic yield of TTE is minimal in low-risk patients with normal hearts. We performed a retrospective chart review of TTEs performed for concern for endocarditis at a pediatric tertiary care referral center in Portland, Oregon. Three hundred patients met inclusion criteria (< 21 years old, completed TTE for IE from 2005 to 2015, no history of congenital heart disease or endocarditis). We recorded findings that met the modified Duke criteria (MDC) including fever, positive blood culture, and vascular/immunologic findings; presence of a central line; whether or not patients were diagnosed with IE clinically; and if any changes to antibiotic regimens were made based on TTE. Ten patients (3%) had echocardiograms consistent with IE. When compared to the clinical diagnosis of IE, the positive predictive value (PPV) of one positive blood culture without other major/minor MDC was 0. Similarly, the PPV of two positive blood cultures without other major/minor criteria was 0.071. Patients should be evaluated using the MDC to assess the clinical probability of IE prior to performing a TTE. Patients with a low probability for IE should not undergo TTE as it has a low diagnostic yield and patients are unlikely to be diagnosed with disease.

Transcatheter closure of perimembranous ventricular septal defects with the Amplatzer Vascular Plug-II.

OBJECTIVE: The aim of this study was to evaluate the safety and efficacy of the Amplatzer Vascular Plug-II used for the closure of perimembranous ventricular septal defects. BACKGROUND: There are no FDA-approved transcatheter devices for the closure of perimembranous ventricular septal defects. Several studies have reported on the use of various devices either off-label or under clinical trial protocols. However these reports have described significant adverse events including residual shunts, complete heart block, arrhythmia, and new valve regurgitations. Thus far, no study on the Amplatzer Vascular Plug-II has been reported. METHODS: We conducted a 4-year retrospective chart review from August, 2010 to August, 2014, of patients with perimembranous ventricular septal defects associated with ventricular septal aneurysm who underwent transcatheter closure using the Amplatzer Vascular Plug-II. RESULTS: A total of 16 patients underwent Amplatzer Vascular Plug-II transcatheter closure of their perimembranous ventricular septal defects. The median age was 2.56 years (range: 0.5-27.3). Their median weight was 13.0 kg (range: 6.9-71.6). The left ventricular median defect size was 9.3 mm (range: 5.9-14.4). The right ventricular median defect size was 3.6 mm (range: 2.3-5.8). All the patients underwent successful device implantation with 83% of the patients having complete echocardiographic closure at the 1-year follow-up; however, one procedure was complicated by early device embolisation. The device was successfully retrieved and replaced with a larger device. There were no device-related outflow tract obstructions, rhythm abnormalities, or haemolysis. CONCLUSION: Application of the Amplatzer Vascular Plug-II for closure of perimembranous ventricular septal defects appears to be a safe and effective treatment option. Prospective clinical trials and longer follow-up periods are warranted.

Neisseria gonorrhoeae MtrCDE Efflux Pump During In Vivo Experimental Genital Tract Infection in Men and Mice Reveals the Presence of Within-Host Colonization Bottleneck.

The MtrCDE efflux pump of Neisseria gonorrhoeae exports a wide range of antimicrobial compounds that the gonococcus encounters at mucosal surfaces during colonization and infection. Here, we evaluate the role of this efflux pump system in strain FA1090 in human male urethral infection with a Controlled Human Infection Model. Using the strategy of competitive multi-strain infection with wild-type FA1090 and an isogenic mutant strain that does not contain a functional MtrCDE pump, we found that the presence of the efflux pump during human experimental infection did not confer a competitive advantage. This finding is in contrast to previous findings in female mice, which demonstrated that gonococci of strain FA19 lacking a functional MtrCDE pump had a significantly reduced fitness compared to the wild type strain in the lower genital tract of female mice. We conducted competitive infections in female mice with FA19 and FA1090 strains, including mutants that do not assemble a functional Mtr efflux pump, demonstrating the fitness advantage provided byt the MtrCDE efflux pump during infection of mice is strain dependent. Our data indicate that new gonorrhea treatment strategies targeting the MtrCDE efflux pump functions may not be universally efficacious in naturally occurring infections. Owing to the equal fitness of FA1090 strains in men, our experiments unexpectedly demonstrated the likely presence of an early colonization bottleneck of N. gonorrhoeae in the human male urethra. TRIAL REGISTRATION: Clinicaltrials.gov NCT03840811 .

Effect of iron depletion in carbohydrate-intolerant patients with clinical evidence of nonalcoholic fatty liver disease.

BACKGROUND & AIMS: Increased body iron, genetic hemochromatosis (GH) mutations, and nonalcoholic fatty liver disease (NAFLD) tend to cluster in carbohydrate-intolerant patients. In an attempt to further clarify the interrelationships among these conditions, we studied 42 carbohydrate-intolerant patients who were free of the common GH mutations C282Y and H63D, and had a serum iron saturation lower than 50%. METHODS: We measured body iron stores, and induced iron depletion to a level of near-iron deficiency (NID) by quantitative phlebotomy. RESULTS: In the 17 patients with clinical evidence of NAFLD, we could not demonstrate supranormal levels of body iron (1.6 +/- 0.2 vs. 1.4 +/- 0.2 g; P = 0.06). However, at NID, there was a 40%-55% improvement (P = 0.05-0.0001) of both fasting and glucose-stimulated plasma insulin concentrations, and near-normalization of serum alanine aminotransferase activity (from 61 +/- 5 to 32 +/- 2 IU/L; P < 0.001). CONCLUSIONS: These results reflect the insulin-sparing effect of iron depletion and indicate a key role of iron and hyperinsulinemia in the pathogenesis of NAFLD.