Host stress drives tolerance and persistence: The bane of anti-microbial therapeutics.

Antibiotic resistance, typically associated with genetic changes within a bacterial population, is a frequent contributor to antibiotic treatment failures. Antibiotic persistence and tolerance, which we collectively term recalcitrance, represent transient phenotypic changes in the bacterial population that prolong survival in the presence of typically lethal concentrations of antibiotics. Antibiotic recalcitrance is challenging to detect and investigate-traditionally studied under in vitro conditions, our understanding during infection and its contribution to antibiotic failure is limited. Recently, significant progress has been made in the study of antibiotic-recalcitrant populations in pathogenic species, including Mycobacterium tuberculosis, Staphylococcus aureus, Salmonella enterica, and Yersiniae, in the context of the host environment. Despite the diversity of these pathogens and infection models, shared signals and responses promote recalcitrance, and common features and vulnerabilities of persisters and tolerant bacteria have emerged. These will be discussed here, along with progress toward developing therapeutic interventions to better treat recalcitrant pathogens.

Estradiol mediates greater germinal center responses to influenza vaccination in female than male mice.

Adult females of reproductive age develop greater antibody responses to inactivated influenza vaccines (IIV) than males. How sex, age, and sex steroid concentrations impact B cells and durability of IIV-induced immunity and protection over 4 months post-vaccination (mpv) was analyzed. Vaccinated adult females had greater germinal center B cell and plasmablast frequencies in lymphoid tissues, higher neutralizing antibody responses 1-4 mpv, and better protection against live H1N1 challenge than adult males. Aged mice, regardless of sex, had reduced B cell frequencies, less durable antibody responses, and inferior protection after challenge than adult mice, which correlated with diminished estradiol among aged females. To confirm that greater IIV-induced immunity was caused by sex hormones, four core genotype (FCG) mice were used, in which the testes-determining gene, Sry, was deleted from chromosome Y (ChrY) and transferred to Chr3 to separate gonadal sex (i.e., ovaries or testes) from sex chromosome complement (i.e., XX or XY complement). Vaccinated, gonadal female FCG mice (XXF and XYF) had greater numbers of B cells, higher antiviral antibody titers, and reduced pulmonary virus titers following live H1N1 challenge than gonadal FCG males (XYM and XXM). To establish that lower estradiol concentrations cause diminished immunity, adult and aged females received either a placebo or estradiol replacement therapy prior to IIV. Estradiol replacement significantly increased IIV-induced antibody responses and reduced morbidity after the H1N1 challenge among aged females. These data highlight that estradiol is a targetable mechanism mediating greater humoral immunity following vaccination among adult females.IMPORTANCEFemales of reproductive ages develop greater antibody responses to influenza vaccines than males. We hypothesized that female-biased immunity and protection against influenza were mediated by estradiol signaling in B cells. Using diverse mouse models ranging from advanced-age mice to transgenic mice that separate sex steroids from sex chromosome complement, those mice with greater concentrations of estradiol consistently had greater numbers of antibody-producing B cells in lymphoid tissue, higher antiviral antibody titers, and greater protection against live influenza virus challenge. Treatment of aged female mice with estradiol enhanced vaccine-induced immunity and protection against disease, suggesting that estradiol signaling in B cells is critical for improved vaccine outcomes in females.

Estradiol Mediates Greater Germinal Center Responses to Influenza Vaccination in Female than Male Mice.

Adult females of reproductive ages develop greater antibody responses to inactivated influenza vaccine (IIV) than males. How sex, age, and sex steroid changes impact B cells and durability of IIV-induced immunity and protection over 4-months post-vaccination (mpv) was analyzed. Vaccinated adult females had greater germinal center (GC) B cell and plasmablast frequencies in lymphoid tissues, higher neutralizing antibody responses 1-4 mpv, and better protection against live H1N1 challenge than adult males. Aged mice, regardless of sex, had reduced B cell frequencies, less durable antibody responses, and inferior protection after challenge than adult mice, which correlated with diminished estradiol among aged females. To confirm that greater IIV-induced immunity was caused by sex hormones, four core genotype (FCG) mice were used, in which the testes determining gene, Sry, was deleted from ChrY and transferred to Chr3, to separate gonadal sex (i.e., ovaries or testes) from sex chromosome complement (i.e., XX or XY complement). Vaccinated, gonadal female FCG mice (XXF and XYF) had greater numbers of B cells, higher antiviral antibody titers, and reduced pulmonary virus titers following live H1N1 challenge than gonadal FCG males (XYM and XXM). To establish that lower estradiol concentrations cause diminished immunity, adult and aged females received either a placebo or estradiol replacement therapy prior to IIV. Estradiol replacement significantly increased IIV-induced antibody responses and reduced morbidity after the H1N1 challenge among aged females. These data highlight that estradiol is a targetable mechanism mediating greater humoral immunity following vaccination among adult females.

A novel rodent model of chronic spinal implant-associated infection.

BACKGROUND CONTEXT: Bacterial infection of spinal instrumentation is a significant challenge in spinal fusion surgery. Although the intraoperative local application of powdered vancomycin is common practice for mitigating infection, the antimicrobial effects of this route of administration are short-lived. Therefore, novel antibiotic-loaded bone grafts as well as a reliable animal model to permit the testing of such therapies are needed to improve the efficacy of infection reduction practices in spinal fusion surgery. PURPOSE: This study aims to establish a clinically relevant rat model of spinal implant-associated infection to permit the evaluation of antimicrobial bone graft materials used in spinal fusion. STUDY DESIGN: Rodent study of chronic spinal implant-associated infection. METHODS: Instrumentation anchored in and spanning the vertebral bodies of L4 and L5 was inoculated with bioluminescent methicillin-resistant Staphylococcus aureus bacteria (MRSA). Infection was monitored using an in vivo imaging system (IVIS) for 8 weeks. Spines were harvested and evaluated histologically, and colony-forming units (CFUs) were quantified in harvested implants and spinal tissue. RESULTS: Postsurgical analysis of bacterial infection in vivo demonstrated stratification between MRSA and phosphate-buffered saline (PBS) control groups during the first 4 weeks of the 8-week infection period, indicating the successful establishment of acute infection. Over the 8-week chronic infection period, groups inoculated with 1 × 105 MRSA CFU and 1 × 106 MRSA CFU demonstrated significantly higher bioluminescence than groups inoculated with PBS control (p = 0.009 and p = 0.041 respectively). Histological examination at 8 weeks postimplantation revealed the presence of abscesses localized to implant placement in all MRSA inoculation groups, with the most pervasive abscess formation in samples inoculated with 1 × 105 MRSA CFU and 1 × 106 MRSA CFU. Quantification of CFU plated from harvested spinal tissue at 8 weeks post-implantation revealed the 1 × 105 MRSA CFU inoculation group as the only group with a significantly greater average CFU count compared to PBS control (p = 0.017). Further, CFU quantification from harvested spinal tissue was greater than CFU quantification from harvested implants across all inoculation groups. CONCLUSION: Our model demonstrated that the inoculation dosage of 1 × 105 MRSA CFU exhibited the most robust chronic infection within instrumented vertebral bodies. This dosage had the greatest difference in bioluminescence signal from control (p < 0.01), the lowest mortality (0% compared to 50% for samples inoculated with 1 × 106 MRSA CFU), and a significantly higher amount of CFUs from harvested spine samples than CFUs from control harvested spine samples. Further, histological analysis confirmed the reliability of this novel rodent model of implanted-associated infection to establish infection and biofilm formation of MRSA for all inoculation groups. CLINICAL SIGNIFICANCE: This model is intended to simulate the infection of instrumentation used in spinal fusion surgeries concerning implant locality and material. This model may evaluate potential antimicrobial and osteogenic biomaterials and investigate the relationship between implant-associated infection and failed fusion.

Integrating Tobacco Use Assessment and Treatment in the Oncology Setting: Quality Improvement Results from the Georgetown Lombardi Smoking Treatment and Recovery Program.

As part of the NCI's Cancer Center Cessation (C3i) initiative, we initiated, expanded, and maintained an evidence-based tobacco treatment program at the Georgetown Lombardi Comprehensive Cancer Center. We present a quality improvement (QI) assessment of the implementation process and patient-level outcomes. At two hematology/oncology outpatient clinical sites, five oncology-based teams (clinical administrators, clinical staff, pharmacy, information technology, and tobacco treatment staff) developed implementation strategies for opt-out patient assessment and enrollment, centralized tobacco treatment, audit, feedback, and staff training. Among eligible patients (tobacco use in ≤30 days), we assessed demographic, clinical, and tobacco-related characteristics to examine predictors of enrollment (baseline completed), treatment engagement (≥one sessions completed), and self-reported 7-day abstinence (6 months post-enrollment). Across both sites, medical assistants screened 19,344 (82.4%) patients for tobacco use, which identified 1345 (7.0%) current tobacco users, in addition to 213 clinician referrals. Of the 687/1256 (54.7%) eligible patients reached, 301 (43.8%) enrolled, and 199 (29.0%) engaged in treatment, of whom 74.5% were African American and 68% were female. At the larger site, significant multivariate predictors of enrollment included African American race (vs. white/other) and clinician referral (vs. MA assessment). Treatment engagement was predicted by greater nicotine dependence, and abstinence (27.4%) was predicted by greater treatment engagement. In summary, the systematic utilization of multiple oncology-based teams and implementation strategies resulted in the development and maintenance of a high-quality, population-based approach to tobacco treatment. Importantly, these strategies addressed inequities in tobacco treatment, as the program reached and engaged a majority-African-American patient population. Finally, the opt-out patient assessment strategy has been implemented in multiple oncology settings at MedStar Health through the Commission on Cancer's Just Ask program.

Protocol for detecting Yersinia pseudotuberculosis nitric oxide exposure during in vitro growth.

Yersinia pseudotuberculosis (Yptb) is a bacterial pathogen that causes foodborne illness. Defense against the host antimicrobial gas, nitric oxide (NO), by the bacterial NO-detoxifying gene, hmp, promotes Yptb replication in mouse models of infection. Here, we detail the use of fluorescent signals as readouts for NO exposure within individual cells and subsequent detection of heterogeneity within a population, using single-cell imaging and analysis. This protocol quantifies NO exposure in culture, without capturing the full complexity of the host environment. For complete details on the use and execution of this protocol, please refer to Patel et al. (2021).

A Randomized Trial of Telephone-Based Smoking Cessation Treatment in the Lung Cancer Screening Setting.

BACKGROUND: Lung cancer mortality is reduced via low-dose computed tomography screening and treatment of early-stage disease. Evidence-based smoking cessation treatment in the lung screening setting can further reduce mortality. We report the results of a cessation trial from the National Cancer Institute's Smoking Cessation at Lung Examination collaboration. METHODS: Eligible patients (n = 818) aged 50-80 years were randomly assigned (May 2017-January 2021) to the intensive vs minimal arms (8 vs 3 phone sessions plus 8 vs 2 weeks of nicotine patches, respectively). Bio-verified (primary) and self-reported 7-day abstinence rates were assessed at 3, 6, and 12 months post random assignment. Logistic regression analyses evaluated the effects of study arm. All statistical tests were 2-sided. RESULTS: Participants reported 48.0 (SD = 17.2) pack-years, and 51.6% were not ready to quit in less than 30 days. Self-reported 3-month quit rates were statistically significantly higher in the intensive vs minimal arm (14.3% vs 7.9%; odds ratio [OR] = 2.00, 95% confidence interval [CI] = 1.26 to 3.18). Bio-verified abstinence was lower but with similar relative differences between arms (9.1% vs 3.9%; OR = 2.70, 95% CI = 1.44 to 5.08). Compared with the minimal arm, the intensive arm was more effective among those with greater nicotine dependence (OR = 3.47, 95% CI = 1.55 to 7.76), normal screening results (OR = 2.58, 95% CI = 1.32 to 5.03), high engagement in counseling (OR = 3.03, 95% CI = 1.50 to 6.14), and patch use (OR = 2.81, 95% CI = 1.39 to 5.68). Abstinence rates did not differ statistically significantly between arms at 6 months (OR = 1.2, 95% CI = 0.68 to 2.11) or 12 months (OR = 1.4, 95% CI = 0.82 to 2.42). CONCLUSIONS: Delivering intensive telephone counseling and nicotine replacement with lung screening is an effective strategy to increase short-term smoking cessation. Methods to maintain short-term effects are needed. Even with modest quit rates, integrating cessation treatment into lung screening programs may have a large impact on tobacco-related mortality.

NO-Stressed Y. pseudotuberculosis Has Decreased Cell Division Rates in the Mouse Spleen.

Fluorescence dilution approaches can detect bacterial cell division events and can detect if there are differential rates of cell division across individual cells within a population. This approach typically involves inducing expression of a fluorescent protein and then tracking partitioning of fluorescence into daughter cells. However, fluorescence can be diluted very quickly within a rapidly replicating population, such as pathogenic bacterial populations replicating within host tissues. To overcome this limitation, we have generated two revTetR reporter constructs, where either mCherry or yellow fluorescent protein (YFP) is constitutively expressed and repressed by addition of tetracyclines, resulting in fluorescence dilution within defined time frames. We show that fluorescent signals are diluted in replicating populations and that signal accumulates in growth-inhibited populations, including during nitric oxide (NO) exposure. Furthermore, we show that tetracyclines can be delivered to the mouse spleen during Yersinia pseudotuberculosis infection and defined a drug concentration that results in even exposure of cells to tetracyclines. We then used this system to visualize bacterial cell division within defined time frames postinfection. revTetR-mCherry allowed us to detect slow-growing cells in response to NO in culture; however, this strain had a growth defect within mouse tissues, which complicated results. To address this issue, we constructed revTetR-YFP using the less toxic YFP and showed that heightened NO exposure correlated with heightened YFP signal, indicating decreased cell division rates within this subpopulation in vivo. This revTetR reporter will provide a critical tool for future studies to identify and isolate slowly replicating bacterial subpopulations from host tissues.

Psychological predictors of delayed active treatment following active surveillance for low-risk prostate cancer: The Patient REported outcomes for Prostate cARE prospective cohort study.

Objectives: In a prospective, comparative effectiveness study, we assessed clinical and psychological factors associated with switching from active surveillance (AS) to active treatment (AT) among low-risk prostate cancer (PCa) patients. Methods: Using ultra-rapid case identification, we conducted pretreatment telephone interviews (N = 1139) with low-risk patients (PSA ≤ 10, Gleason≤6) and follow-up interviews 6-10 months post-diagnosis (N = 1057). Among men remaining on AS for at least 12 months (N = 601), we compared those who continued on AS (N = 515) versus men who underwent delayed AT (N = 86) between 13 and 24 months, using Cox proportional hazards models. Results: Delayed AT was predicted by time dependent PSA levels (≥10 vs. <10; HR = 5.6, 95% CI 2.4-13.1) and Gleason scores (≥7 vs. ≤6; adjusted HR = 20.2, 95% CI 12.2-33.4). Further, delayed AT was more likely among men whose urologist initially recommended AT (HR = 2.13, 95% CI 1.07-4.22), for whom tumour removal was very important (HR = 2.18, 95% CI 1.35-3.52), and who reported greater worry about not detecting disease progression early (HR = 1.67, 1.05-2.65). In exploratory analyses, 31% (27/86) switched to AT without evidence of progression, while 4.7% (24/515) remained on AS with evidence of progression. Conclusions: After adjusting for clinical evidence of disease progression over the first year post-diagnosis, we found that urologists' initial treatment recommendation and patients' early treatment preferences and concerns about AS each independently predicted undergoing delayed AT during the second year post-diagnosis. These findings, along with almost one-half undergoing delayed AT without evidence of progression, suggest the need for greater decision support to remain on AS when it is clinically indicated.

Dynamic PET-facilitated modeling and high-dose rifampin regimens for Staphylococcus aureus orthopedic implant-associated infections.

Staphylococcus aureus is a major human pathogen causing serious implant­associated infections. Combination treatment with rifampin (10 to 15 mg/kg per day), which has dose-dependent activity, is recommended to treat S. aureus orthopedic implant­associated infections. Rifampin, however, has limited bone penetration. Here, dynamic 11C-rifampin positron emission tomography (PET) performed in prospectively enrolled patients with confirmed S. aureus bone infection (n = 3) or without orthopedic infection (n = 12) demonstrated bone/plasma area under the concentration-time curve ratio of 0.14 (interquartile range, 0.09 to 0.19), exposures lower than previously thought. PET-based pharmacokinetic modeling predicted rifampin concentration-time profiles in bone and facilitated studies in a mouse model of S. aureus orthopedic implant infection. Administration of high-dose rifampin (human equipotent to 35 mg/kg per day) substantially increased bone concentrations (2 mg/liter versus <0.2 mg/liter with standard dosing) in mice and achieved higher bacterial killing and biofilm disruption. Treatment for 4 weeks with high-dose rifampin and vancomycin was noninferior to the recommended 6-week treatment of standard-dose rifampin with vancomycin in mice (risk difference, −6.7% favoring high-dose rifampin regimen). High-dose rifampin treatment ameliorated antimicrobial resistance (0% versus 38%; P = 0.04) and mitigated adverse bone remodeling (P < 0.01). Last, whole-genome sequencing demonstrated that administration of high-dose rifampin in mice reduced selection of bacterial mutations conferring rifampin resistance (rpoB) and mutations in genes potentially linked to persistence. These data suggest that administration of high-dose rifampin is necessary to achieve optimal bone concentrations, which could shorten and improve treatments for S. aureus orthopedic implant infections.

Modifying TIMER to generate a slow-folding DsRed derivative for optimal use in quickly-dividing bacteria.

It is now well appreciated that members of pathogenic bacterial populations exhibit heterogeneity in growth rates and metabolic activity, and it is known this can impact the ability to eliminate all members of the bacterial population during antibiotic treatment. It remains unclear which pathways promote slowed bacterial growth within host tissues, primarily because it has been difficult to identify and isolate slow growing bacteria from host tissues for downstream analyses. To overcome this limitation, we have developed a novel variant of TIMER, a slow-folding fluorescent protein, named DsRed42, to identify subsets of slowly dividing bacteria within host tissues. The original TIMER folds too slowly for fluorescence accumulation in quickly replicating bacterial species (Escherichia coli, Yersinia pseudotuberculosis), however DsRed42 accumulates red fluorescence in late stationary phase cultures of E. coli and Y. pseudotuberculosis. We show DsRed42 signal also accumulates during exposure to sources of nitric oxide (NO), suggesting DsRed42 signal detects growth-arrested bacterial cells. In a mouse model of Y. pseudotuberculosis deep tissue infection, DsRed42 signal was detected, and primarily accumulates in bacteria expressing markers of stationary phase growth. There was no significant overlap between DsRed42 signal and NO-exposed subpopulations of bacteria within host tissues, suggesting NO stress was transient, allowing bacteria to recover from this stress and resume replication. This novel DsRed42 variant represents a tool that will enable additional studies of slow-growing subpopulations of bacteria, specifically within bacterial species that quickly divide.

Yersinia pseudotuberculosis: Cultivation, Storage, and Methods for Introducing DNA.

Yersinia pseudotuberculosis has been studied for many decades, and research on this microbe has taught us a great deal about host-pathogen interactions, bacterial manipulation of host cells, virulence factors, and the evolution of pathogens. This microbe should not be cultivated at 37°C because this is a trigger that the bacterium uses to sense its presence within a mammalian host and results in expression of genes necessary to colonize a mammalian host. Prolonged growth at this temperature can result in accumulation of mutations that reduce the virulence of the strain, so all protocols need to be modified for growth at room temperature, or 26°C. This article describes protocols for cultivating this microbe and for its long-term storage and its genetic manipulation by transformation and conjugation. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Growth of Y. pseudotuberculosis from a stock Basic Protocol 2: Growth of Y. pseudotuberculosis in liquid medium from a single colony Basic Protocol 3: Freezing Y. pseudotuberculosis in glycerol for long-term storage Basic Protocol 4: Transformation of Y. pseudotuberculosis by electroporation Basic Protocol 5: Tri-parental mating/conjugation.

Subpopulations of Stressed Yersinia pseudotuberculosis Preferentially Survive Doxycycline Treatment within Host Tissues.

Severe systemic bacterial infections result in colonization of deep tissues, which can be very difficult to eliminate with antibiotics. It remains unclear if this is because antibiotics are not reaching inhibitory concentrations within tissues, if subsets of bacteria are less susceptible to antibiotics, or if both contribute to limited treatment efficacy. To detect exposure to doxycycline (Dox) present in deep tissues following treatment, we generated a fluorescent transcriptional reporter derived from the tet operon to specifically detect intracellular tetracycline exposure at the single bacterial cell level. Dox exposure was detected in the spleen 2 h after intraperitoneal injection, and by 4 h postinjection, this treatment resulted in a significant decrease in viable Yersinia pseudotuberculosis bacteria in the spleen. Nitric oxide-stressed bacteria preferentially survived treatment, suggesting that stress was sufficient to alter Dox susceptibility. Many bacteria (∼10%) survived a single dose of Dox, and the antibiotic accumulated at the periphery of microcolonies to growth inhibitory concentrations until 48 h posttreatment. After this time point, antibiotic concentrations decreased and bacterial growth resumed. Dox-treated mice eventually succumbed to the infection, albeit with significantly prolonged survival relative to that of untreated mice. These results indicate that Dox delivery by intraperitoneal injection results in rapid diffusion of inhibitory concentrations of antibiotic into the spleen, but stressed cells preferentially survive drug treatment, and bacterial growth resumes once drug concentrations decrease. This fluorescent reporter strategy for antibiotic detection could easily be modified to detect the concentration of additional antimicrobial compounds within host tissues following drug administration.IMPORTANCE Bacterial infections are very difficult to treat when bacteria spread into the bloodstream and begin to replicate within deep tissues, such as the spleen. Subsets of bacteria can survive antibiotic treatment, but it remains unclear if this survival is because of limited drug diffusion into tissues, or if there are changes within the bacteria, promoting survival of some bacterial cells. Here, we have developed a fluorescent reporter to detect doxycycline (Dox) diffusion into host tissues, and we show that Dox impacts the bacterial population within hours of administration and inhibits bacterial growth for 48 h. However, bacterial growth resumes when antibiotic concentrations decrease. Subsets of bacteria, stressed by the host response to infection, survive Dox treatment at a higher rate. These results provide critical information about the dynamics that occur within deep tissues following antibiotic administration and suggest that subsets of bacteria are predisposed to survive inhibitory concentrations of antibiotic before exposure.

Topologically correct synthetic reconstruction of pathogen social behavior found during Yersinia growth in deep tissue sites.

Within deep tissue sites, extracellular bacterial pathogens often replicate in clusters that are surrounded by immune cells. Disease is modulated by interbacterial interactions as well as bacterial-host cell interactions resulting in microbial growth, phagocytic attack and secretion of host antimicrobial factors. To overcome the limited ability to manipulate these infection sites, we established a system for Yersinia pseudotuberculosis (Yptb) growth in microfluidics-driven microdroplets that regenerates microbial social behavior in tissues. Chemical generation of nitric oxide (NO) in the absence of immune cells was sufficient to reconstruct microbial social behavior, as witnessed by expression of the NO-inactivating protein Hmp on the extreme periphery of microcolonies, mimicking spatial regulation in tissues. Similarly, activated macrophages that expressed inducible NO synthase (iNOS) drove peripheral expression of Hmp, allowing regeneration of social behavior observed in tissues. These results argue that topologically correct microbial tissue growth and associated social behavior can be reconstructed in culture.

For the Greater (Bacterial) Good: Heterogeneous Expression of Energetically Costly Virulence Factors.

Bacterial populations are phenotypically heterogeneous, which allows subsets of cells to survive and thrive following changes in environmental conditions. For bacterial pathogens, changes within the host environment occur over the course of the immune response to infection and can result in exposure to host-derived, secreted antimicrobials or force direct interactions with immune cells. Many recent studies have shown host cell interactions promote virulence factor expression, forcing subsets of bacterial cells to battle the host response, while other bacteria reap the benefits of this pacification. It still remains unclear whether virulence factor expression is truly energetically costly within host tissues and whether expression is sufficient to impact the growth kinetics of virulence factor-expressing cells. However, it is clear that slow-growing subsets of bacteria emerge during infection and that these subsets are particularly difficult to eliminate with antibiotics. This minireview will focus on our current understanding of heterogenous virulence factor expression and discuss the evidence that supports or refutes the hypothesis that virulence factor expression is linked to slowed growth and antibiotic tolerance.

Selecting Active Surveillance: Decision Making Factors for Men with a Low-Risk Prostate Cancer.

Background. Men with a low-risk prostate cancer (PCa) should consider observation, particularly active surveillance (AS), a monitoring strategy that avoids active treatment (AT) in the absence of disease progression. Objective. To determine clinical and decision-making factors predicting treatment selection. Design. Prospective cohort study. Setting. Kaiser Permanente Northern California (KPNC). Patients. Men newly diagnosed with low-risk PCa between 2012 and 2014 who remained enrolled in KPNC for 12 months following diagnosis. Measurements. We used surveys and medical record abstractions to measure sociodemographic and clinical characteristics and psychological and decision-making factors. Men were classified as being on observation if they did not undergo AT within 12 months of diagnosis. We performed multivariable logistic regression analyses. Results. The average age of the 1171 subjects was 61.5 years (s = 7.2 years), and 81% were white. Overall, 639 (57%) were managed with observation; in adjusted analyses, significant predictors of observation included awareness of low-risk status (odds ratio 1.75; 95% confidence interval 1.04-2.94), knowing that observation was an option (3.62; 1.62-8.09), having concerns about treatment-related quality of life (1.21, 1.09-1.34), reporting a urologist recommendation for observation (8.20; 4.68-14.4), and having a lower clinical stage (T1c v. T2a, 2.11; 1.16-3.84). Conversely, valuing cancer control (1.54; 1.37-1.72) and greater decisional certainty (1.66; 1.18-2.35) were predictive of AT. Limitations. Results may be less generalizable to other types of health care systems and to more diverse populations. Conclusions. Many participants selected observation, and this was associated with tumor characteristics. However, nonclinical decisional factors also independently predicted treatment selection. Efforts to provide early decision support, particularly targeting knowledge deficits, and reassurance to men with low-risk cancers may facilitate better decision making and increase uptake of observation, particularly AS.

Iron-Sulfur Cluster Repair Contributes to Yersinia pseudotuberculosis Survival within Deep Tissues.

To successfully colonize host tissues, bacteria must respond to and detoxify many different host-derived antimicrobial compounds, such as nitric oxide (NO). NO has direct antimicrobial activity through attack on iron-sulfur (Fe-S) cluster-containing proteins. NO detoxification plays an important role in promoting bacterial survival, but it remains unclear if repair of Fe-S clusters is also important for bacterial survival within host tissues. Here we show that the Fe-S cluster repair protein YtfE contributes to the survival of Yersinia pseudotuberculosis within the spleen following nitrosative stress. Y. pseudotuberculosis forms clustered centers of replicating bacteria within deep tissues, where peripheral bacteria express the NO-detoxifying gene hmp. ytfE expression also occurred specifically within peripheral cells at the edges of microcolonies. In the absence of ytfE, the area of microcolonies was significantly smaller than that of the wild type (WT), consistent with ytfE contributing to the survival of peripheral cells. The loss of ytfE did not alter the ability of cells to detoxify NO, which occurred within peripheral cells in both WT and ΔytfE microcolonies. In the absence of NO-detoxifying activity by hmp, NO diffused across ΔytfE microcolonies, and there was a significant decrease in the area of microcolonies lacking ytfE, indicating that ytfE also contributes to bacterial survival in the absence of NO detoxification. These results indicate a role for Fe-S cluster repair in the survival of Y. pseudotuberculosis within the spleen and suggest that extracellular bacteria may rely on this pathway for survival within host tissues.

Study protocol for a telephone-based smoking cessation randomized controlled trial in the lung cancer screening setting: The lung screening, tobacco, and health trial.

Lung cancer mortality can be reduced by 20% via low dose CT lung cancer screening (LCS) and treatment of early-stage disease. Providing tobacco use treatment to high risk cigarette smokers in the LCS setting may result in health benefits beyond the impact of LCS. As one of the nine trials in the National Cancer Institute's Smoking Cessation at Lung Examination (SCALE) collaboration, the goal of the Lung Screening, Tobacco, and Health (LSTH) trial is to develop a scalable and cost-effective cessation intervention for subsequent implementation by LCS programs. Guided by the RE-AIM Framework, the LSTH trial is a two-arm RCT (N = 1330) enrolling English- and Spanish-speaking smokers registered for LCS at one of seven collaborating sites. Participants are randomly assigned to Usual Care (UC; three proactive telephone counseling sessions/two weeks of nicotine patches) vs. Intensive Telephone Counseling (ITC; eight proactive sessions/eight weeks of nicotine patches, plus discussion of the LCS results to increase motivation to quit). Telephone counseling is provided by tobacco treatment specialists. To increase continuity of care, referring physicians are notified of participant enrollment and smoking status following the intervention. Outcomes include: 1) self-reported 7-day, 30-day, and sustained abstinence, and biochemically-verified at 3-, 6-, and 12-months post-randomization, 2) reach and engagement of the interventions, and 3) cost-effectiveness of the interventions. The Cancer Intervention and Surveillance Modeling Network (CISNET) will model long-term impacts of six SCALE trials on the cost per life year saved, quality-adjusted life years saved, lung cancer mortality reduction, and population mortality. CLINICAL TRIALS REGISTRATION: The trial is registered at clinical trials.gov: NCT03200236.

One for All, but Not All for One: Social Behavior during Bacterial Diseases.

It has been known for decades that individual cells within pathogenic bacterial populations have reduced antibiotic susceptibility, which is linked to decreased metabolic rates. A similar phenomenon occurs with virulence-associated proteins, as reduced expression is associated with increased fitness of individual cells. Non-producers within the population can benefit from the virulence proteins produced by others in the population without suffering a fitness cost, thus maintaining a genetically uniform population. Cooperative behavior has been reported for Salmonella and Yersinia, consistent with selection of social behavior to retain genes associated with pathogenesis; however, cooperation was unclear within Mycobacterium populations. This review focuses on these recent descriptions of cooperation, discusses the mechanisms driving heterogeneity, and evaluates the evidence that expression of virulence-associated proteins comes at a fitness cost.

All Yersinia Are Not Created Equal: Phenotypic Adaptation to Distinct Niches Within Mammalian Tissues.

Yersinia pseudotuberculosis replicates within mammalian tissues to form clustered bacterial replication centers, called microcolonies. A subset of bacterial cells within microcolonies interact directly with host immune cells, and other subsets of bacteria only interact with other bacteria. This establishes a system where subsets of Yersinia have distinct gene expression profiles, which are driven by their unique microenvironments and cellular interactions. When this leads to alterations in virulence gene expression, small subsets of bacteria can play a critical role in supporting the replication of the bacterial population, and can drive the overall disease outcome. Based on the pathology of infections with each of the three Yersinia species that are pathogenic to humans, it is likely that this specialization of bacterial subsets occurs during all Yersiniae infections. This review will describe the pathology that occurs during infection with each of the three human pathogenic Yersinia, in terms of the structure of bacterial replication centers and the specific immune cell subsets that bacteria interact with, and will also describe the outcome these interactions have or may have on bacterial gene expression.