Evaluation of Mycobacterium avium subsp. paratuberculosis isocitrate lyase (IcL) and ABC transporter (BacA) knockout mutants as vaccine candidates.

There has been little success in controlling Johne's disease, caused by Mycobacterium avium subsp. paratuberculosis, due to suboptimal diagnostics and the ineffectiveness of available vaccines. By knocking out BacA and IcL, genes required for MAP survival in dairy calves, two live-attenuated vaccine candidates were created. This study evaluated the host-specific attenuation of MAP IcL and BacA mutants in mouse and calf models, as well as the elicited immune responses. Deletion mutants were generated in MAP strain A1-157 through specialized transduction and found viable in vitro. First, the mutants' attenuation and elicited cytokine secretion were assessed in a mouse model, 3 weeks after intraperitoneal inoculation with MAP strains. Later, vaccine strains were assessed in a natural host infection model where calves received 109CFU oral dose of MAP wild-type or mutant strains at 2 weeks old. Transcription levels of cytokines in PBMCs were evaluated at 12-, 14-, and 16-weeks post-inoculation (WPI) and MAP colonization in tissue was assessed at 4.5 months after inoculation. Whereas both vaccine candidates colonized mouse tissues similarly to wild-type strain, both failed to persist in calf tissues. In either mouse or calf models, gene deletion did not reduce immunogenicity. Instead, inoculation with ΔBacA induced a greater upregulation of proinflammatory cytokines than ΔIcL and wild-type in both models and a greater expansion of cytotoxic and memory T-cells than uninfected control in calves. ΔBacA and wild-type strains significantly increased secretion of IP-10, MIG, TNFα, and RANTES in mice serum compared to uninfected control. This agreed with upregulation of IL-12, IL-17, and TNFα in calves inoculated with ΔBacA at all time points. The ΔBacA also gave rise to greater populations of CD4+CD45RO+, and CD8+ cells than uninfected control calves at 16 WPI. Low survival rate of MAP in macrophages co-incubated with PBMCs isolated from the ΔBacA group indicated that these cell populations are capable of killing MAP. Overall, the immune response elicited by ΔBacA is stronger compared to ΔIcL and it is maintained over two different models and over time in calves. Further investigation is warranted to evaluate the BacA mutant's protection against MAP infection as a live attenuated vaccine candidate.

Povidone-iodine irrigation reduces infection after total hip and knee arthroplasty.

INTRODUCTION: One of the most important challenges faced by orthopedic surgeons is periprosthetic joint infection (PJI). PJI is a common cause for total joint arthroplasty failure with an incidence of 0.3-1.9%. PJI can be devastating for the patient and extremely costly for the healthcare system. There is concern that a major cause of PJI is intra-operative colonization and recent studies have shown a decrease in PJI with the use of dilute povidone-iodine (Betadine®, Avrio Health L.P, Stamford, CT) irrigation prior to wound closure. This study presents our experience with the use of dilute Betadine® irrigation prior to wound closure and its effect on our post-operative hip and knee arthroplasty acute infection rate. MATERIALS AND METHODS: Retrospective chart review performed at our hospital looking at PJI amongst patients who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) between 2013 and 2017 comparing different irrigation methods (n = 3232). The study group (n = 1207) underwent irrigation prior to wound closure with dilute Betadine for 3 min and the control group (n = 1511) underwent irrigation using normal saline (NS). RESULTS: Using a logistic regression model where the following variables were adjusted for; ASA, age, sex, foley insertion, surgical duration and diabetes mellitus status a statistical significant reduction was seen in any infection (OR 0.45 [0.22; 0.89], p value < 0.05) and SSI (OR 0.30 [0.13; 0.70], p value 0.01) with the Betadine group. No significant reduction was seen with deep infections with the Betadine group compared to the NS group. CONCLUSION: PJI is a devastating complication following total joint arthroplasty and we found Betadine compared to NS irrigation provides an inexpensive and simple method to lower any PJI and more specifically SSI in THA and TKA. LEVEL OF EVIDENCE: III.

Oral vaccination stimulates neutrophil functionality and exerts protection in a Mycobacterium avium subsp. paratuberculosis infection model.

Mycobacterium avium subsp. paratuberculosis (Map) causes paratuberculosis (PTB), a granulomatous enteritis in ruminants that exerts high economic impact on the dairy industry worldwide. Current vaccines have shown to be cost-effective against Map and in some cases confer beneficial non-specific effects against other pathogens suggesting the existence of trained immunity. Although Map infection is mainly transmitted by the fecal-oral route, oral vaccination has not been deeply studied. Therefore, the aim of this study was to compare the oral route with a set of mycobacterial and non-mycobacterial vaccines with a subcutaneously administered commercially available vaccine. Training effects on polymorphonuclear neutrophils (PMNs) and homologous and heterologous in vivo protection against Map were investigated in the rabbit infection model. Oral vaccination with inactivated or live vaccines was able to activate mucosal immunity as seen by elevation of serum IgA and the expression of IL4 in peripheral blood mononuclear cells (PBMCs). In addition, peripheral PMN phagocytosis against Map was enhanced by vaccination and extracellular trap release against Map and non-related pathogens was modified by both, vaccination and Map-challenge, indicating trained immunity. Finally, PBMCs from vaccinated animals stimulated in vitro with Map antigens showed a rapid innate activation cytokine profile. In conclusion, our data show that oral vaccination against PTB can stimulate neutrophil activity and both innate and adaptive immune responses that correlate with protection.

Operating Room Educational Environment in Canada: Perceptions of Surgical Residents.

OBJECTIVE: The educational experience in operating rooms (OR) plays a central role in the transformation of a trainee into a surgeon. As Canadian residency programs transition to competency-based medical education, and since most surgical competencies are attained in the OR, we investigated the perceptions of Canadian surgical residents about their OR learning environment. DESIGN: Cross-sectional, national survey. SETTING: An online questionnaire, including the validated 40-item operating room educational environment measure (OREEM) inventory, was sent to residency programs of all surgical specialties in Canada. The OREEM assesses the trainees' perceptions of the "trainer and training," "learning opportunities," "atmosphere in the operating room," "supervision, workload, and support," Each individual item was rated using a 5-point Likert scale ranging from "strongly disagree" (scores 1) to "strongly agree" (scores 5). The mean score of each individual item was measured, and the mean scores of each subscale and an overall score of the questions were also measured. PARTICIPANTS: Surgical residents in Canada. RESULTS: Four hundred thirty residents were included for final analysis. The overall mean OREEM score was 3.72 ± 0.4. "Atmosphere in the OR" was the subscale with the highest mean score (3.87 ± 0.5), while "supervision, workload, and support" had the lowest subscale mean score (3.49 ± 0.5). The overall OREEM mean score for junior and senior residents was 3.67 ± 0.4 and 3.80 ± 0.4, respectively (p = 0.001). No significant differences were seen in the mean OREEM score between males and females or different surgical programs. Nevertheless, general surgery had the lowest "supervision, workload, and support" subscale score (3.27 ± 0.5; p < 0.001). CONCLUSIONS: The overall educational environment in OR may be considered satisfactory as perceived by Canadian surgical residents; however, several areas for potential improvement are identified and suggestions for optimizing the learning environment are described.

Inducing cellular immune responses with a marked Mycobacterium avium subsp. paratuberculosis strain in dairy calves.

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Johne's disease, a chronic granulomatous enteritis with a high global prevalence in dairy cattle. This disease causes significant economic loss in the dairy industry and has been challenging to control, as current diagnostic assays are low in sensitivity and specificity, and previously developed vaccines do not prevent infection and face regulatory concerns due to interference with bovine tuberculosis diagnostics. To remediate this issue, positive and negative immune markers were created in a MAP strain as a step towards a vaccine capable of differentiating infected from vaccinated animals (DIVA). A gene coding for an immunogenic protein (MAP1693c) in the MAP genome was replaced with a library of epitope-tagged immunogenic genes (pepA) via a stable allelic exchange method. These markers were evaluated in a calf infection trial, where Holstein-Friesian dairy calves were inoculated at two weeks of age with either the marked strain or the parent strain, or remained uninfected controls. Cellular immune responses to the markers were measured using an interferon gamma release assay (IGRA). There were no MAP1693c marker-specific differences in cellular immune responses between infection groups. A scrambled version of the HA (human influenza hemagglutinin) epitope, but not the actual HA epitope, induced a significant IFN-γ response in marker-infected calves compared to WT-infected and uninfected groups at 4.5 months post-inoculation. This scrambled HA epitope thus holds potential as a diagnostic tool as part of a DIVA vaccine for Johne's disease.

Disparities in hepatitis C virus infection screening among Baby Boomers in the United States.

BACKGROUND: The study objective was to identify potential sociodemographic disparities in hepatitis C virus (HCV) infection screening among Baby Boomers in the United States. METHODS: We analyzed cross-sectional data from the 2013-2016 National Health Interview Survey. The outcome was whether a person had an HCV infection screening (yes/no). Key independent variables were race/ethnicity, geographic region, poverty level, education level, and health insurance status. Multivariate logistic regression was performed to examine the factors associated with the receipt of HCV screening. RESULTS: The study sample included a total of 41,914 United States Baby Boomers, who represented a population size of 69,554,339. In 2016, the HCV screening rate among Baby Boomers was 13.9%. In the multivariate logistic regression, we found that Asians had 27% lower odds of receiving an HCV screening compared to Blacks (odds ratio [OR] = 0.74, P = .02). People who lived in the Northeast, South, and West had a higher likelihood of having an HCV screening than those who lived in the Midwest (OR = 1.33, 1.39, and 1.69, respectively; all P values <.001). Additionally, people with less education, lower income, and private health insurance were significantly less likely to have an HCV screening. CONCLUSION: Future studies or interventions are needed to target these disadvantaged populations to improve HCV screening in Baby Boomers.