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1.
JAMA Dermatol ; 158(10): 1216-1218, 2022 Oct 01.
Article in English | MEDLINE | ID: mdl-35921087

ABSTRACT

This case report describes a woman in her 40s with a 2-week history of abrupt painful ulcerations of the perineum.


Subject(s)
Perineum , Skin Ulcer , Humans , Skin Ulcer/diagnosis , Skin Ulcer/etiology
2.
Dermatitis ; 31(5): 321-327, 2020.
Article in English | MEDLINE | ID: mdl-32947460

ABSTRACT

BACKGROUND: The ideal patient-reported outcome measure to assess sleep disturbance in atopic dermatitis (AD) has not been determined. OBJECTIVE: We sought to determine the measurement properties of the Patient-Reported Outcomes Measurement Information System (PROMIS) Itch Questionnaire Mood and Sleep (PIQ-MS), Sleep Disturbance (SD), Sleep-Related Impairment (SRI), and Epworth Sleepiness Scale (ESS) in adults with AD. METHODS: A prospective dermatology practice-based study was performed using questionnaires and evaluation by a dermatologist (n=611). RESULTS: PIQ-MS, PROMIS SD, SRI, and ESS had good convergent validity with intensity and frequency of sleep disturbance, Patient-Oriented Eczema Measure, Eczema Area and Severity Index, total and objective-Scoring AD, Numerical Rating Scale of worst-itch and average-itch, and Dermatology Life Quality Index. PIQ-MS had significantly better correlations with other severity measures than the other sleep measures (Fisher z-scores, P≤0.007). PIQ-MS, and to lesser extent PROMIS SD, PROMIS SRI and ESS had good discriminant validity. All four sleep assessments showed fair responsiveness to change of severity of sleep-disturbance, AD and itch. PIQ-MS had the best reliability. PIQ-MS, PROMIS SD, SRI and ESS showed good internal consistency and were feasible for use in clinical practice. CONCLUSIONS: PIQ-MS, followed by PROMIS SD, had the best construct validity and reliability in adult AD.


Subject(s)
Dermatitis, Atopic/complications , Patient Reported Outcome Measures , Quality of Life/psychology , Severity of Illness Index , Sleep Wake Disorders/etiology , Adult , Dermatitis, Atopic/psychology , Female , Humans , Male , Middle Aged , Prospective Studies , Sleep Wake Disorders/psychology , Surveys and Questionnaires
3.
Ann Allergy Asthma Immunol ; 124(3): 261-266, 2020 03.
Article in English | MEDLINE | ID: mdl-31830585

ABSTRACT

BACKGROUND: The optimal approaches for monitoring sleep disturbances in adults with atopic dermatitis (AD) is not established. Multiple patient-reported outcome measures for AD and itch have sleep-related items. These items have not been validated previously. OBJECTIVE: Assess the measurement properties of sleep-related items from the Patient-Oriented Eczema Measure (POEM), SCORing AD (SCORAD), 5-dimensions of itch (5D), and ItchyQOL in adults with AD. METHODS: We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 115). RESULTS: There was modest overlap and weak-moderate concordance of responses to the different assessments. Regarding concurrent validity, POEM-sleep, SCORAD-sleep, 5D-sleep, and ItchyQOL-sleep showed moderate correlations with each other. Regarding convergent validity, all items showed moderate correlation with total POEM, but weak correlations with Eczema Area and Severity Index (EASI), objective and total SCORAD, moderate to strong correlations with mean ItchyQOL and Dermatology Life Quality Index (DLQI), but poor or no significant correlation with Numeric Rating Scale (NRS) for worst or average itch. Regarding discriminant validity, all items showed significant and stepwise increases with increasing self-reported and physician-reported AD severity (Kruskal-Wallis, P < .01 for all). Floor effects were observed for POEM-sleep (n = 53, 46.1%), SCORAD-sleep (n = 28, 24.4%), 5D-sleep (n = 41, 35.7%), and ItchyQOL-sleep (n = 33, 28.7%); no ceiling effects were observed. Change in sleep-related item scores showed moderate strong correlations with change in POEM, 5Ditch, mean ItchyQOL, DLQI, objective and total SCORAD, and EASI, but inconsistent correlations with change of itch severity. CONCLUSION: Sleep-related items from POEM, SCORAD, 5D and ItchyQOL showed good validity and responsiveness to monitor sleep disturbances in adult AD patients.


Subject(s)
Dermatitis, Atopic/epidemiology , Quality of Life , Sleep Wake Disorders/epidemiology , Sleep , Adolescent , Adult , Aged , Aged, 80 and over , Dermatitis, Atopic/complications , Dermatitis, Atopic/diagnosis , Female , Humans , Male , Middle Aged , Patient Reported Outcome Measures , Prospective Studies , Pruritus , Public Health Surveillance , Reproducibility of Results , Self Report , Sleep Wake Disorders/etiology , Surveys and Questionnaires , Young Adult
4.
J Am Acad Dermatol ; 82(5): 1174-1180, 2020 May.
Article in English | MEDLINE | ID: mdl-31812620

ABSTRACT

BACKGROUND: The Patient-Reported Outcomes Measurement Information System (PROMIS) Itch Questionnaire (PIQ) was recently developed. OBJECTIVE: To validate PIQ short forms in adults with AD. METHODS: Self-administered questionnaires and skin examinations were performed in 239 adults with atopic dermatitis (AD) in a dermatology practice setting. RESULTS: PIQ items had good content validity. PIQ item bank T-scores strongly correlated with each other, moderately correlated with numeric and verbal rating scales for worst or average itch and with itch frequency, moderately to strongly correlated with patient-oriented eczema measure, and weakly to moderately correlated with the Eczema Area and Severity Index and Objective-Scoring AD (Spearman correlations, P < .0001). There were significant and stepwise increases of T-scores for all item banks with increasing patient-reported global severity (Wilcoxon rank sum test, P < .0001). However, there was limited ability to discriminate between the lowest or highest 2 levels of AD or itch severity. Item banks showed good internal consistency (Cronbach α, 0.91-0.95). No differential item functioning was identified by age, sex, race/ethnicity, or educational level. There were floor effects for total scores, particularly in almost clear/mild AD or itch. LIMITATIONS: Single-center study. CONCLUSIONS: PIQ item bank short forms showed good content and construct validity and are feasible for potential use in clinical trials and practice.


Subject(s)
Dermatitis, Atopic/physiopathology , Patient Reported Outcome Measures , Pruritus/physiopathology , Quality of Life , Surveys and Questionnaires , Adult , Aged , Dermatitis, Atopic/psychology , Feasibility Studies , Female , Humans , Male , Middle Aged , Pruritus/psychology , Reproducibility of Results , Severity of Illness Index , Statistics, Nonparametric , United States
5.
Clin Dermatol ; 36(5): 595-605, 2018.
Article in English | MEDLINE | ID: mdl-30217272

ABSTRACT

Atopic dermatitis (AD) is driven by a complex gene-environment interaction. Many of the risk factors and genetic underpinning previously observed for pediatric AD may not apply to adult atopic dermatitis, suggesting that these may largely be different disorders. Whereas AD is classically thought of as a pediatric disease, recent studies have shown high rates of disease in adults as well. Risk factors for persistence of childhood-onset AD, as well as adult-onset AD, are reviewed. Adults with AD are particularly vulnerable to exogenous insults from the outside environment, including climate, ultraviolet exposure, pollution, irritants and pruritogens, and microbes. Finally, adult AD is associated with a substantial health care burden, with increased utilization, direct and indirect costs of care, and lost work productivity.


Subject(s)
Dermatitis, Atopic/epidemiology , Adult , Age of Onset , Aged , Aged, 80 and over , Cost of Illness , Dermatitis, Atopic/economics , Dermatitis, Atopic/ethnology , Dermatitis, Atopic/genetics , Health Care Costs , Humans , Internationality , Middle Aged , Prevalence , Risk Factors , Sex Factors , United States/epidemiology , Young Adult
6.
J Allergy Clin Immunol Pract ; 6(4): 1306-1312, 2018.
Article in English | MEDLINE | ID: mdl-29133223

ABSTRACT

BACKGROUND: Little is known about adult-onset atopic dermatitis (AD). OBJECTIVE: To determine the associations and clinical characteristics of adult-onset AD. METHODS: A prospective study of 356 adults with AD (age ≥18 years) was performed using standardized questionnaires and examination. AD severity was assessed using the Patient-Oriented Eczema Measure, Eczema Area and Severity Index, Scoring Atopic Dermatitis, body surface area, and numeric rating scale for itch and sleeplessness. Latent class analysis was used to determine dominant clinical phenotypes. Multivariate logistic regression was used to determine the relationship between adult-onset AD and distinct phenotypes. RESULTS: One hundred forty-nine adults (41.9%) reported onset of AD during adulthood, with 87 (24.4%) after the age of 50 years. Adult- versus childhood-onset AD was associated with birthplace outside the United States (χ2, P = .0008), but not sex, race/ethnicity, current smoking status, or alcohol consumption (P ≥ .11); and decreased personal history of asthma, hay fever, and food allergy and family history of asthma and food allergy (P ≤ .0001 for all). There was no significant difference in the Eczema Area and Severity Index, Scoring Atopic Dermatitis, body surface area, numeric rating scale for itch and sleeplessness, or Patient-Oriented Eczema Measure between adult- and childhood-onset AD (Mann-Whitney U test, P ≥ .10). Latent class analysis identified 3 classes: (1) high probability of flexural dermatitis and xerosis with intermediate to high probabilities of head, neck, and hand dermatitis; (2) high probability of flexural dermatitis and xerosis, but low probabilities of head, neck, and hand dermatitis; and (3) lower probability of flexural dermatitis, but the highest probabilities of virtually all other signs and symptoms. Adult-onset AD was significantly associated with class 1 (multivariate logistic regression; adjusted odds ratio, 5.54; 95% CI, 1.59-19.28) and class 3 (adjusted odds ratio, 14.03; 95% CI, 2.33-85.50). CONCLUSIONS: Self-reported adult-onset AD is common and has distinct phenotypes with lesional predilection for the hands and/or head/neck.


Subject(s)
Dermatitis, Atopic/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Phenotype , Prospective Studies , Self Report , Severity of Illness Index , Surveys and Questionnaires , Young Adult
7.
Dermatol Online J ; 24(9)2018 09 15.
Article in English | MEDLINE | ID: mdl-30677841

ABSTRACT

The original article was published on August 15, 2018 and corrected on September 15, 2018. The revised version of the article removes a co-author, unintentionally retained during the editorial proofing process. This change appears in the revised online PDF copy of this article.


Subject(s)
Conflict of Interest/economics , Dermatology/ethics , Editorial Policies , Periodicals as Topic/ethics , Dermatology/economics , Humans , Periodicals as Topic/economics
8.
Dermatol Online J ; 24(8)2018 08 15.
Article in English | MEDLINE | ID: mdl-30677845

ABSTRACT

BACKGROUND: Financial relationships between editorial board members of peer-reviewed journals and pharmaceutical and medical device manufacturing companies can potentially lead to biases and loss of objectivity of the medical literature. The purpose of this study was to evaluate the potential financial conflicts of interest that exist among editorial board members of dermatology journals. METHODS: Editorial board members for 36 dermatology journals were identified and searched using the Open Payments database on the Center for Medicare and Medicaid Services website. The total amount of general payments made to these physician editors were collected and stratified using a tier system: 1) nothing reported, 2) >$0 and <$10,000, 3) >$10,000 and <$100,000, and 4) >$100,000. RESULTS: We identified 551 editors from 36 dermatology journals for use in our analysis. Some form of general payment was made to 87% of these physicians (480 of 551). Four journals had >25% of their editorial staff receiving >$100,000. CONCLUSIONS: Financial relationships exist between editorial board members of dermatology journals and pharmaceutical/medical device manufacturing companies, which could lead to financial conflicts of interest. Publications coming from journals with highly paid physician editors have more potential to be biased.


Subject(s)
Conflict of Interest , Dermatology , Financial Support , Periodicals as Topic , Physicians , Centers for Medicare and Medicaid Services, U.S. , Databases, Factual , Drug Industry , Equipment and Supplies , Humans , Manufacturing Industry , United States
9.
Ann Allergy Asthma Immunol ; 119(6): 548-552.e3, 2017 12.
Article in English | MEDLINE | ID: mdl-29223299

ABSTRACT

BACKGROUND: Atopic dermatitis (AD) is associated with itch, skin inflammation and barrier disruption, and scratching, all of which may be associated with skin pain. OBJECTIVE: To characterize the patient burden of skin pain in AD. METHODS: We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist. RESULTS: Overall, 305 patients (age range, 13-97 years) were included in the study, with 564 encounters. The cohort included 195 females (63.9%) and 193 whites (63.7%). The mean (SD) age at enrollment was 42.3 (18.1) years, and the mean (SD) age of patient-reported AD onset was 29.6 (31.9) years. At baseline, 144 patients (42.7%) reported skin pain in the past week, with 42 (13.8%) reporting severe or very severe pain. Twenty-four (16.8%) thought the skin pain was part of their itch, 16 (11.2%) from scratching, and 77 (72.0%) from both. Patients with skin pain were more likely to describe their itch using terms that resembled neuropathic pain. Prevalence of skin pain was increased in patients with vs without excoriations (72.6% vs 57.6%; χ2 test P = .02) but not other morphologic characteristics. Skin pain severity was most strongly correlated with the Patient-Oriented Eczema Measure (Spearman ρ = 0.54), followed by ItchyQOL (ρ = 0.52), 5-dimensions of itch scale (ρ = 0.47), Dermatology Life Quality Index (ρ = 0.45), numeric rating scale for itch (ρ = 0.43) and sleep (ρ = 0.36), Patient Health Questionnaire 9 (ρ = 0.36), patient-reported global AD severity (ρ = 0.34), Eczema Area and Severity Index (ρ = 0.23), and objective Scoring AD index (ρ = 0.20) (P < .001 for all). Patients with both severe itch and pain vs those with only one or neither symptom being severe had significant increases in all these measures. CONCLUSION: Skin pain is a common and burdensome symptom in AD. Skin pain severity should be assessed with itch severity in AD patients and may be an important end point for monitoring treatment response.


Subject(s)
Dermatitis, Atopic/diagnosis , Pain Measurement/methods , Pain/diagnosis , Pruritus/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prospective Studies , Quality of Life , Severity of Illness Index , Surveys and Questionnaires , Young Adult
10.
Ann Allergy Asthma Immunol ; 119(5): 435-440, 2017 11.
Article in English | MEDLINE | ID: mdl-29150071

ABSTRACT

BACKGROUND: Bleach baths have been proposed as a treatment for decreasing the severity of atopic dermatitis (AD). However, conflicting results have been found regarding their efficacy. OBJECTIVE: To determine the efficacy of bleach vs water baths at decreasing AD severity. METHODS: We performed a systematic review of all studies evaluating the efficacy of bleach baths for AD. Cochrane, EMBASE, GREAT, LILACS, MEDLINE, and Scopus were searched. Two authors independently performed study selection and data extraction. RESULTS: Five studies were included in the review. Four studies reported significantly decreased AD severity in patients treated with bleach on at least 1 time point. However, of 4 studies comparing bleach with water baths, only 2 found significantly greater decreases in AD severity with bleach baths, 1 found greater decreases with water baths, and 1 found no significant differences. In pooled analyses, there were no significant differences observed between bleach vs water baths at 4 weeks vs baseline for the Eczema Area and Severity Index (I2 = 98%; random effect regression model, P = .16) or body surface area (I2 = 96%; P = .36). CONCLUSION: Although bleach baths are effective in decreasing AD severity, they do not appear to be more effective than water baths alone. Future larger-scale, well-designed randomized controlled trials are needed.


Subject(s)
Balneology/methods , Bleaching Agents/therapeutic use , Dermatitis, Atopic/therapy , Disease Progression , Humans , Treatment Outcome
11.
Int J Radiat Oncol Biol Phys ; 99(4): 854-858, 2017 11 15.
Article in English | MEDLINE | ID: mdl-28847411

ABSTRACT

PURPOSE: To inform goals of care discussions at the time of palliative radiation therapy (RT) consultation, we sought to characterize intensive care unit (ICU) outcomes for patients treated with palliative RT compared to all other patients with metastatic cancer admitted to the ICU. METHODS AND MATERIALS: We conducted a retrospective cohort study of patients with metastatic cancer admitted to an ICU in a tertiary medical center from January 2010 to September 2015. We compared in-hospital mortality between patients who received palliative RT in the 12 months before admission and all other patients with metastatic cancer. We used multivariable logistic regression to evaluate the association between receipt of palliative RT and in-hospital mortality, adjusting for patient characteristics and acute illness severity. RESULTS: Among 1424 patients with metastatic cancer, 11.3% (n=161) received palliative RT before ICU admission. In-hospital mortality was 36.7% for palliative RT patients, compared with 16.6% for other patients with metastatic cancer (P<.001). Receipt of palliative RT was associated with increased in-hospital mortality (odds ratio 2.08, 95% confidence interval 1.34-3.21, P=.001), after adjusting for patient characteristics and severity of critical illness. Only 34 patients (21.1%) treated with palliative RT received additional cancer-directed treatment after ICU admission. CONCLUSIONS: For patients with metastatic cancer, prior treatment with palliative RT is associated with increased in-hospital mortality after ICU admission. Nearly half of patients previously treated with palliative RT either died during hospitalization or were discharged with hospice care, and few received further cancer-directed therapy. Palliative RT referral may represent an opportunity to discuss end-of-life treatment preferences with patients and families.


Subject(s)
Hospital Mortality , Intensive Care Units , Neoplasms/mortality , Neoplasms/radiotherapy , Palliative Care/methods , Terminal Care , Adult , Aged , Aged, 80 and over , Female , Hospice Care/statistics & numerical data , Humans , Intensive Care Units/statistics & numerical data , Logistic Models , Male , Middle Aged , Neoplasms/pathology , Odds Ratio , Organ Dysfunction Scores , Palliative Care/statistics & numerical data , Retrospective Studies , Terminal Care/statistics & numerical data , Treatment Outcome
12.
J Cancer Res Clin Oncol ; 143(11): 2341-2350, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28752235

ABSTRACT

PURPOSE: We examined overall survival in a large cohort of patients with human papillomavirus (HPV)-positive and HPV-negative non-oropharyngeal squamous cell carcinoma of the head and neck (non-OPSCC). METHODS: Patients diagnosed with non-OPSCC and known HPV status were identified in the National Cancer Database (NCDB). Multivariate logistic regression was applied to examine factors associated with HPV status. Multivariate analysis was utilized to determine factors correlated with overall survival. Propensity score-weighted Kaplan-Meier estimation was used to adjust for confounders in survival analyses. Multiple imputation method was used for sensitivity analysis. RESULTS: We identified 19,993 non-OPSCC patients with 5070 being positive for HPV in the NCDB. Median follow-up was 23.5 months. HPV-positive patients were more commonly male, white, with a lower comorbidity index score, presenting with T-stage <2, and N-stage ≥1. Unadjusted 3-year overall survival was 62% and 80% for HPV-negative and HPV-positive patients, respectively (p < 0.0001). On multivariate analysis, mortality was reduced for HPV-positive patients with early stage (HR = 0.68) and locally advanced disease (HR = 0.46). Adjusted 3-year overall survival was 65% for HPV-negative and 76% for HPV-positive patients (p < 0.0001). The survival advantage of HPV was maintained in all subsites and robust on sensitivity analysis. CONCLUSIONS: Patients with HPV-positive non-OPSCC exhibit similar characteristics as HPV-positive OPSCC. Overall survival was significantly higher for patients with HPV-positive versus HPV-negative non-OPSCC. These data reveal that HPV-positive non-OPSCC represent a favorable cohort that warrants recognition in the design of future clinical trial investigation.


Subject(s)
Carcinoma, Squamous Cell/pathology , Oropharyngeal Neoplasms/pathology , Papillomavirus Infections/complications , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/therapy , Carcinoma, Squamous Cell/virology , Combined Modality Therapy , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Staging , Oropharyngeal Neoplasms/therapy , Oropharyngeal Neoplasms/virology , Papillomaviridae , Papillomavirus Infections/virology , Prognosis , Retrospective Studies , Survival Rate , Young Adult
14.
Pract Radiat Oncol ; 7(2): e91-e97, 2017.
Article in English | MEDLINE | ID: mdl-28274406

ABSTRACT

PURPOSE: The purpose of this article is to report the long-term rate and timing of complications associated with postmastectomy radiation therapy (PMRT) following immediate breast reconstruction in a large patient population. METHODS AND MATERIALS: We identified and reviewed the charts of all patients with stages I through IIIC breast cancer who underwent mastectomy with immediate reconstruction followed by subsequent radiation therapy between November 1997 and May 2010. We aimed to assess the rate of major complications, defined as events requiring a separate and distinct procedure. Statistical analysis between variables was evaluated using Fisher exact test and Pearson χ2 Elder et al. (2005) test. RESULTS: In total, 134 patients met inclusion criteria for having adequate long-term follow-up and documentation. The median follow-up for all patients was 77.4 months (range, 6-185 months). The overall major complication rate was found to be 44%. Nine patients (6.7%) experienced complications for which a secondary procedure could not be performed to retain a reconstructed breast. The average time between initiation of PMRT and the first major complication was 13.5 months, with 68.3% of first major complications occurring within 1 year of PMRT initiation and 81.7% within 2 years. The difference in incidence of major complications for patients undergoing immediate tissue expander/implant reconstruction followed by PMRT was not statistically different when compared with that for patients with immediate autologous tissue reconstruction followed by PMRT (47.3% vs 30.4%, P = .168). CONCLUSIONS: The risk of first major complications and reconstruction loss in patients undergoing PMRT on immediately reconstructed breasts is greatest within 1 year of beginning radiation therapy and decreases significantly with time. Immediate autologous tissue reconstruction followed by PMRT can be performed with reasonable complication rates.


Subject(s)
Breast Neoplasms/radiotherapy , Breast Neoplasms/surgery , Mammaplasty/methods , Mastectomy , Postoperative Complications/epidemiology , Radiotherapy, Adjuvant/adverse effects , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Incidence , Middle Aged , Retrospective Studies , Tissue Expansion Devices , Treatment Outcome
15.
J Arthroplasty ; 31(9 Suppl): 192-6, 2016 09.
Article in English | MEDLINE | ID: mdl-27421583

ABSTRACT

BACKGROUND: The arthroplasty population is increasingly comorbid, and current quality improvement initiatives demand accurate risk stratification. Metabolic syndrome (MetS) has been identified as a risk factor for adverse events after arthroplasty; however, its interaction with obesity in contributing to risk is unclear. METHODS: A retrospective analysis of all Medicare patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at a single institution from 2009 to 2013 investigated the interaction between MetS, body mass index (BMI), and risk for Centers for Medicare and Medicaid Services (CMS)-reportable complications, readmission, and discharge disposition. RESULTS: A total of 1462 patients (942 TKA, 538 THA) were included, of which 16.2% had MetS. Regression analysis found that MetS was significantly related to risk of CMS complications (odds ratio [OR] = 1.96, 95% confidence interval [CI] 1.16-3.31, P = .012) and nonhome discharge (OR = 1.78, 95% CI 1.39-2.27, P < .001), but not readmission (OR = 1.23, 95% CI 0.7-2.18, P = .485). Within the MetS cohort, increasing BMI was not associated with increasing complications (P = .726) or readmissions (P = .206) but was associated with nonhome discharge (OR = 1.191 per unit increase in BMI, 95% CI 1.038-1.246, P = .001). CONCLUSION: MetS increases risk for CMS-reportable complications and nonhome discharge disposition after THA and TKA regardless of BMI. Obesity is of less value than MetS in assessing overall risk for complication after THA and TKA.


Subject(s)
Arthroplasty, Replacement, Hip/adverse effects , Arthroplasty, Replacement, Knee/adverse effects , Metabolic Syndrome/complications , Obesity/complications , Postoperative Complications/etiology , Female , Humans , Male , Medicare , Odds Ratio , Patient Discharge , Regression Analysis , Retrospective Studies , Risk Assessment , Risk Factors , United States
16.
J Bacteriol ; 195(2): 368-77, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23144253

ABSTRACT

Proteus mirabilis is an opportunistic pathogen that is frequently associated with urinary tract infections. In the lab, P. mirabilis cells become long and multinucleate and increase their number of flagella as they colonize agar surfaces during swarming. Swarming has been implicated in pathogenesis; however, it is unclear how energetically costly changes in P. mirabilis cell morphology translate into an advantage for adapting to environmental changes. We investigated two morphological changes that occur during swarming--increases in cell length and flagellum density--and discovered that an increase in the surface density of flagella enabled cells to translate rapidly through fluids of increasing viscosity; in contrast, cell length had a small effect on motility. We found that swarm cells had a surface density of flagella that was ∼5 times larger than that of vegetative cells and were motile in fluids with a viscosity that inhibits vegetative cell motility. To test the relationship between flagellum density and velocity, we overexpressed FlhD(4)C(2), the master regulator of the flagellar operon, in vegetative cells of P. mirabilis and found that increased flagellum density produced an increase in cell velocity. Our results establish a relationship between P. mirabilis flagellum density and cell motility in viscous environments that may be relevant to its adaptation during the infection of mammalian urinary tracts and movement in contact with indwelling catheters.


Subject(s)
Flagella/physiology , Locomotion , Proteus mirabilis/cytology , Proteus mirabilis/physiology , Trans-Activators/biosynthesis , Environmental Microbiology , Gene Expression , Trans-Activators/genetics
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