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PubMed1991

Evidence for recent diarrhoeal morbidity as a risk factor for persistent diarrhoea: a case-control study.

The association between persistent diarrhoea and 'recent morbidity' defined as that occurring within the two-month period immediately preceding the onset of persistent diarrhoea was investigated in a population-based case-control study in rural North India. In two separate matched case-control analyses children with persistent diarrhoea (cases) were compared to population controls (five controls matched to each case) and acute diarrhoeal controls (three controls matched to each case). After correcting for possible confounding variables, comparing children with persistent diarrhoea and matched population controls, presence of a recent diarrhoeal illness was significantly associated with persistent diarrhoea with an odds ratio (OR) 2.6 (95%) confidence interval (CI): 1.1-7.1; p less than 0.05); during infancy this OR was 5.2 (95% CI: 1.0-31.9; p less than 0.01). Comparing children with persistent diarrhoea to matched acute diarrhoeal controls, presence of recent diarrhoeal illness was associated with an OR of 5.1 (95% CI: 1.3-20.3) in favour of the episode becoming persistent; in infants this OR was 10.4 (95% CI: 1.1-132.4; p less than 0.001).

Acute Disease↗
PubMed2003

Persistency of use of COX-2-specific inhibitors and non-specific non-steroidal anti-inflammatory drugs (NSAIDs) in Quebec.

The effectiveness of pharmacological therapies is dependent in part on patient persistency with the prescribed therapeutic regimen. In the case of non-specific non-steroidal anti-inflammatory drugs (NSAIDs), effectiveness is often compromised by undesirable side-effects, poor compliance or discontinuation of therapy. While patterns of utilization of non-specific NSAIDs have been investigated, few data are available on the patterns of persistency for cyclooxygenase (COX)-2-specific inhibitors. This study used a provincial health-care system database in Quebec, Canada, to determine the duration of treatment in new users of COX-2-specific inhibitors and non-specific NSAIDs over the first 3 months of treatment, and to characterize the factors associated with treatment persistency. Results demonstrate that the median duration of treatment was longer among patients initially prescribed COX-2-specific inhibitors (30 days and 23 days for celecoxib and rofecoxib respectively) than in those prescribed non-selective NSAIDs (10 days). Although the percentage of patients remaining on COX-2-specific drugs declined over the course of treatment, few patients on either celecoxib or rofecoxib switched drugs, either to the other COX-2-specific inhibitor or to non-specific NSAIDs. Factors associated with persistent drug use were: COX-2-specific inhibitors, age, and the use of gastroprotective agents either at treatment initiation or during follow-up. Dosage, chronic disease score and prescriber's specialty were only marginally associated with persistency. Prior use of gastroprotective agents was associated with lower persistency. Although the limitations of this study, which included lack of information on the indication for the prescription and the reason for switch or discontinuation, preclude definite conclusions regarding patterns of use of these drugs, the data suggest that the use of COX-2-specific inhibitors may result in increased persistency with treatment.

Adolescent↗
PubMed2006

Persistent negative symptoms in schizophrenia: an overview.

Persistent negative symptoms represent an alternative approach for assessing negative symptoms in the context of clinical trials. Persistent negative symptoms are designed to capture those symptoms that lead to functional impairment but are currently understudied and for which there are no currently available effective treatments. Persistent negative symptoms differ from the 2 most commonly used approaches: primary, enduring negative symptoms or deficit symptoms and negative symptoms broadly defined to include negative symptoms, regardless of their etiology or duration. In contrast to deficit symptoms, persistent negative symptoms may include secondary negative symptoms. However, in contrast to negative symptoms broadly defined, the secondary negative symptoms included in the assessment of persistent negative symptoms only include those that have failed to respond to usual treatments for secondary negative symptoms. In consequence, the presence of persistent negative symptoms identifies a patient population with clinically relevant symptomatology, which is larger than the one with the deficit syndrome but less heterogeneous than that captured through the use of a nonrestrictive definition of negative symptoms. This may facilitate the selection of subjects for inclusion into research and efforts to develop new pharmacological treatments and enhance our understanding of a relevant clinical problem. Ultimately, the investigation of the different entities characterized by negative symptoms, such as persistent negative symptoms, and the enhanced understanding of their biological and clinical characteristics may help to unravel the psychopathological and biological heterogeneity of schizophrenia.

Affect↗
PubMed1999

Persistent and recurrent blue nevi.

Persistence of common melanocytic nevi has been fairly well characterized, clinically and histologically. In contrast, persistence of blue nevi has been reported infrequently. To define this entity better, nine cases of biologically persistent and clinically recurrent blue nevi are described. The persistent lesions in four cases were spindle-fascicular blue nevi; one showed senescent or "ancient" change and one had additional deep penetrating/epithelioid blue nevus features with atypical changes worrisome for malignancy. These changes included increased cellularity, cellular pleomorphism, mitotic figures, and a lymphocytic infiltrate. Three were biphasic dendritic-sclerotic/spindle-fascicular blue nevi, one of which had atypical changes. One case was a dendritic-sclerotic ("common") blue nevus. The original histology in one case was unavailable, but the recurrence was a combined blue nevus. The interval from initial biopsy to biopsy of the recurrent lesion was often longer (mean 2.7 years) for recurrent blue nevi than for recurrent common compound or intradermal melanocytic nevi. In addition, in contrast to recurrent common melanocytic nevi, the recurrence, in at least one case, extended beyond the scar of the original excision. These cases demonstrated that blue nevi of all histiotypes and combinations are capable of persistence with clinical recurrence. The persistence usually was histologically similar to the original, but in some cases was more "cellular" because, for the most part, the excisions of the persistent lesion revealed a deeper spindle-fascicular ("cellular") component not evident in the original superficial biopsy. In two cases, the original blue nevus appeared completely banal, but the persistent/recurrent lesions were histologically distinct and demonstrated atypical histologic features. Yet, follow-up (average 3.7 years) supports benign biology. Clinical recurrence is often associated with malignant transformation in blue nevus, but this series demonstrates that malignant tumor progression is not necessarily the case. In the absence of necrosis en mass, marked cytologic atypia, and frequent mitotic figures, the described atypical morphologic parameters in previously biopsied small blue nevi are probably reactive and "pseudomalignant." Awareness of this potential change may avoid diagnostic and prognostic errors.

Adolescent↗
PubMed2002

A case of clear cell adenocarcinoma of the müllerian duct in persistent müllerian duct syndrome: the first reported case.

We report a case of a 67-year-old man with clear cell adenocarcinoma of the remnant uterus in persistent Müllerian duct syndrome. He had a normal penis, urethra, and scrotum, and there was also a vagina and uterus. He died in a traffic accident, and clear cell adenocarcinoma was discovered incidentally at autopsy. Clear cell adenocarcinoma of the remnant uterus metastasized to the retroperitoneal lymph nodes and bilateral lungs. Persistent Müllerian duct syndrome is characterized by the persistence of Müllerian derivatives in otherwise normally virilized males. A variety of germ cell tumors of the testis have been reported in association with persistent Müllerian duct syndrome. However, no malignant change of the persistent Müllerian duct structures has been reported. This represents the first reported case of malignant change of the persistent Müllerian duct structures in persistent Müllerian duct syndrome.

Accidents, Traffic↗
PubMed2002

Persistent pain after cardiac surgery: an audit of high thoracic epidural and primary opioid analgesia therapies.

UNLABELLED: Persistent pain is an underreported morbidity after cardiac surgery. We sent pain surveys to all patients who underwent coronary artery bypass graft surgery from 1997 to 1999 from a single surgeon's experience. Two analgesia strategies were used: high thoracic epidural (HTEA) or IV and oral opiates (OPIOID) for 48-72 h after surgery. Persistent pain was defined as pain still present two or more months after surgery, and all questions referred to the time of survey only. From 356 questionnaires, 305 patients responded, and 61 of them refused consent, leaving 244 patients with complete surveys (HTEA, 150 patients [69%]; OPIOID, 94 patients [68%]). The incidence of persistent pain at any site was 29% and for sternotomy was 25%. The intensity of pain reported was mild, with only 7% reporting interference with daily living. Other common locations of persistent pain were the shoulders (17.4%), back (15.9%), and neck (5.8%). Twenty patients (8%) described symptoms suggestive of the internal mammary artery syndrome. A comparative audit of the HTEA and OPIOID groups showed no significant differences in the frequency or intensity of pain, although the time of survey from operation was longer in the OPIOID group. Mild persistent chest pain after sternotomy is common but infrequently interferes with daily life. IMPLICATIONS: Persistent wound pain after coronary artery bypass surgery is common, but it is usually is mild and infrequently interferes with daily living. An audit of two pain relief strategies (epidural analgesia or opiate analgesia) did not show any difference in the incidence of persistent pain.

Activities of Daily Living↗
PubMed2001

Persistence of intracellular HIV-1 mRNA correlates with HIV-1-specific immune responses in infected subjects on stable HAART.

OBJECTIVE: To determine if low level, persistent, HIV-1 replication within specific immune cells contributes to HIV-1-specific immune responsiveness. DESIGN: We analyzed 59 HIV-1-infected subjects on stable highly active antiretroviral therapy (HAART) therapy (not including zidovudine) with suppressed plasma viremia (< 400 copies/ml) for phenotypic and lymphoproliferative correlates of immune function. METHODS: Peripheral blood mononuclear cells were collected for immunophenotyping, lymphoproliferative assays, and simultaneous immunophenotyping/ultrasensitive in situ hybridization. Plasma was collected for plasma viral load as determined by the Ultra Sensitive Roche Amplicor RT-PCR. Descriptive statistics (mean and SD, median, first and third quartiles) were determined for all variables in two groups defined as having persistent viral replication present or absent. The two-sided Wilcoxon test (continuity correction, 0.5) was used to compare lymphocyte phenotypes, lymphoproliferative assay responses, intracellular gag-pol mRNA, lowest CD4 counts and CD4% of these two groups. RESULTS: HIV-1 replication in CD4, CD45RO memory T lymphocytes persists in spite of undetectable plasma viral load. Patients (n = 24) with persistent intracellular expression of HIV-1 mRNA (> 0.3%) showed significant in vitro proliferative responses to HIV-1 p24 (stimulation index > or = 10) compared to patients (n = 35) without persistent intracellular replication. The group with persistent HIV-1 replication in cells showed no significant response to the recall antigen tetanus toxoid but a trend toward higher responses to pathogen antigens. There were no differences between the groups in the prevalence of AIDS or occurrences of opportunistic infections; however, the high viral persistence group was more HAART experienced (P < 0.05). CONCLUSIONS: These results suggest that HIV-1-specific immune responses correlate with evidence of ongoing HIV-1 replication.

Antiretroviral Therapy, Highly Active↗
PubMed1995

Etiology and epidemiology of persistent diarrhea in northeastern Brazil: a hospital-based, prospective, case-control study.

With the improved therapy for acute diarrhea, persistent diarrhea (> 14 days) is emerging as a major problem in developing countries. However, the etiologies and pathogenesis of persistent diarrhea remain poorly understood. We conducted a prospective case-control study in children < 3 years old presenting to the hospital with persistent diarrhea in Fortaleza, Brazil. Over the study period (August 1988 to March 1991), 56 children seen with persistent diarrhea, 52 children seen with acute diarrhea, and 42 controls attending the same hospital/clinic for illnesses other than diarrhea were enrolled. A potential pathogen was found in 91% of children with persistent diarrhea and 90% of those with acute diarrhea versus 45% of controls (both p's < 0.01). Thirty-four percent of persistent (19/56) and 38% of acute (20/52) diarrhea cases versus 2% (1/42) of controls (both p's < 0.01) had multiple pathogens. Enteroaggregative Escherichia coli (EAggEC) were found in 68% (38/56) of children with persistent diarrhea versus 31% (13/42) of controls (p < 0.01) and in 46% (24/52) of those with acute diarrhea. Furthermore, when the EAggEC were subdivided into aggregative adherence (AA) gene probe positive (18/56; 32%) and negative (20/56; 36%), both subgroups were still significantly different from controls [6/42 (14%) and 7/42 (17%), respectively; both p's < 0.05].(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed2006

Predictors of low risk of persistent trophoblastic disease in molar pregnancies.

OBJECTIVE: To search for predictive factors for low risk of persistent trophoblastic disease in patients with molar pregnancies. METHODS: A total of 270 consecutively collected, histologically confirmed hydatidiform moles were classified by ploidy using karyotyping and flow cytometry. The parental origin of the genome was determined by analysis of microsatellite polymorphisms. Data on clinical features and pathology reports were collected for each patient. RESULTS: The observed frequency of persistent trophoblastic disease in patients with triploid moles was 0 of 105, (95% confidence interval 0-2.8%), whereas 28 of 162 patients with diploid molar pregnancies developed persistent trophoblastic disease (P < .001). Patients with a diploid mole and an initial hCG level lower than 49,000 units per liter did not develop persistent trophoblastic disease (P = .03). CONCLUSION: The risk of persistent trophoblastic disease after a triploid mole is very low. By combining the present data with data from published studies with valid ploidy assessment, the frequency of persistent trophoblastic disease in patients with triploid moles is 0 of 196 (95% confidence interval 0-1.5%). We suggest that the surveillance program for patients with triploid molar pregnancies is shortened. Initial hCG less than 49,000 units per liter is a possible predictor of low risk of persistent trophoblastic disease in women with diploid molar pregnancies, but this observation needs confirmation in larger studies.

Adult↗
PubMed2006

Healthcare and workloss costs associated with patients with persistent asthma in a privately insured population.

OBJECTIVE: The objective of this study was to estimate annual healthcare and workloss costs of patients with persistent asthma by severity. METHODS: A persistent asthma patient sample (<65 years) was selected from an employer claims database. Asthma persistence and severity were determined by a novel algorithm based on Health Plan Employer Data and Information Set criteria, Leidy's Reliever and Oral Steroid Method, and Global Initiative for Asthma guidelines. Healthcare costs were compared between asthma patients and demographically matched controls and by asthma severity. RESULTS: Average annual excess costs for persistent patients were $4412 for health care and $924 for workloss (P < 0.01). Although costs for severe patients were higher than moderate patients (P < 0.05), moderate patients' costs were similar to that for mild patients. Persistent use of inhaled corticosteroids was lower in mild (9.0%) relative to moderate (78.1%) and severe (86.4%) patients. CONCLUSIONS: Persistent asthma is expensive. Underutilization of inhaled corticosteroids is higher in patients with mild persistent asthma.

Adolescent↗
PubMed2004

When can persistent hydroureteronephrosis in posterior urethral valve disease be considered residual stretching?

PURPOSE: Persistent hydroureteronephrosis (HUN) is often seen in boys with a history of a posterior urethral valve even years after valve ablation and it is often assumed to represent residual stretching. We determined the association of HUN with urodynamic abnormalities, the effect on HUN of treating these abnormalities and when persistent HUN could be considered residual stretching. MATERIALS AND METHODS: Of 71 patients with a posterior urethral valve evaluated after valve ablation 20 (28.2%) had persistent HUN in a total of 32 renal units (RUs). The degree of HUN was graded as mild, moderate or severe. Videourodynamics were performed in all patients with persistent HUN and abnormal urodynamic findings were aggressively treated. HUN was then reassessed and categorized as resolved, improved or unchanged. RESULTS: Abnormal urodynamic findings, primarily hypocompliance and instability, were noted in all 20 patients with HUN. All patients compliant with treatment showed dramatic improvement or complete resolution of abnormal urodynamic parameters. The 32 RUs with persistent HUN were initially graded as mild (8), moderate (13) and severe (11). HUN resolved in 15 RUs and improved to a lower grade in 11 in 26 of the 27 RUs (96.3%) in the 17 patients compliant with treatment. The 3 boys (5 RUs) who were noncompliant with treatment had neither decreased HUN nor improved urodynamic parameters. The 12 of 27 RUs (44.4%) in the treatment group in which HUN failed to resolve completely had no distal ureteral obstruction or identifiable persistent urodynamic abnormality and, thus, they can be labeled as having residual stretching. CONCLUSIONS: Persistent HUN following valve ablation should not be considered residual dilatation until a thorough urodynamic evaluation has been done and any abnormal parameters are addressed. With correction of these abnormal parameters one can expect significant lessening of HUN and hopefully improved long-term preservation of renal function.

Child↗
PubMed2006

Adherence and persistence associated with the pharmacologic treatment of osteoporosis in a managed care setting.

BACKGROUND: The effectiveness of chronic therapies can be compromised by poor adherence and persistence. MATERIALS AND METHODS: Investigators identified a continuously benefit-eligible cohort of women from a large, geographically diverse, national managed care plan who were newly diagnosed and treated for osteoporosis with alendronate, risedronate, or raloxifene. Drug utilization parameters were evaluated over a 12-month follow-up period for the study population. Adherence was assessed using a medication possession ratio calculated as total days of therapy for medication dispensed/365 days of study follow-up. Persistence was defined as continuous therapy on the same drug for each month over the entire study period. Adherence and persistence were also evaluated for all three study agents in women > or = 65 years of age. RESULTS: In the study cohort (N = 10,566), 12-month adherence/ persistence rates were alendronate 61%/21%, risedronate 58%/19%, and raloxifene 54%/16%. Rates in women > or = 65 years were similar to those in the entire study cohort. Weekly bisphosphonate users had slightly higher 12-month adherence (63% versus 54%, P < 0.05) and persistence (22% versus 19%, P = NS) rates than did daily users, independent of agent. CONCLUSION: Chronic oral-dosed osteoporosis therapies are associated with poor adherence and persistence, regardless of age or dosing regimen. Drug therapies and patient management approaches associated with improved adherence and persistence could improve the likelihood of achieving the therapeutic benefits observed in rigorously controlled clinical trials.

Aged↗
PubMed2006

Persistence with polypharmacy and excessive dosing in patients with schizophrenia treated in four European countries.

The purpose of this study was to calculate the proportion of patients with schizophrenia receiving persistent antipsychotic polypharmacy and excessive dosing in four European countries; to test the hypothesis that excessive dosing and/or antipsychotic polypharmacy is associated with higher levels of psychopathology; and to establish whether use of second-generation antipsychotics is a protective or a risk factor for polypharmacy and excessive dosing. Participants with schizophrenia were recruited from patients under the care of psychiatric services serving geographical catchment areas in Croydon (UK), Verona (Italy), Amsterdam (Netherlands), and Leipzig (Germany). We defined patients persistently receiving high antipsychotic dose (i.e. excessive dosing) as those with a prescribed daily dose/defined daily dose ratio of >1.5 both at initial assessment and after 1 year of follow-up. Similarly, we defined patients persistently receiving polypharmacy as those being prescribed two or more antipsychotic drugs both at baseline and at follow-up. A sample of 375 participants with schizophrenia was analyzed. A proportion of 28% of patients persistently received high-dose antipsychotic drugs, and a proportion of 13% of patients persistently received antipsychotic polypharmacy. In the multivariate analysis, psychopathology was not a predictor of persistent polypharmacy and excessive dosing; similarly, use of second-generation antipsychotics was not associated with polypharmacy and excessive dosing; however, persistence with high antipsychotic doses was predicted by baseline use of first-generation antipsychotics and second-generation antipsychotics concurrently. Antipsychotic drug use for patients with schizophrenia is only sometimes satisfactory and offers the opportunity of improvement. Clinicians should consider that dose reduction strategies have been shown to be a feasible intervention in patients with schizophrenia.

Adolescent↗
PubMed1985

Influence of interferon on persistent infection caused by Borna disease virus in vitro.

The effect of interferon (IFN) on infection and maintenance of persistent infection of Borna disease (BD) virus in cell cultures was investigated. Acutely BD virus-infected primary rabbit brain and rat lung cells produced significant levels of interferon detectable 3 days post-infection in the culture supernatants. Rat brain and rat lung cells persistently infected with BD virus produced only moderate levels of IFN over a long period. In contrast, persistently infected Madin-Darby canine kidney (MDCK) cells did not produce detectable amounts of IFN. Exogenous homologous IFN completely inhibited the expression of BD virus antigen in acutely infected rabbit brain cells, when added during the first 24 h after infection. IFN added later (2 to 6 days post-infection) reduced virus titres to different degrees depending on the onset of treatment. However, IFN added to persistently infected rat lung cells did not appear to influence the degree or quality of BD virus antigen expression or the intracellular amount of infectious virus. Two facts indicate that IFN is not involved in the establishment or maintenance of persistent BD virus infection in vitro. Thus, MDCK cells, which could not be induced to produce IFN, can be readily persistently infected with BD virus in vitro, and exogenous IFN did not appear to influence persistent BD virus infection.

Animals↗
PubMed1988

Phenotypes of St Louis encephalitis virus mutants produced in persistently infected mosquito cell cultures.

Viral mutants that appeared during long-term persistent infections of mosquito cell cultures (Aedes albopictus, A. dorsalis and Culex tarsalis) with St Louis encephalitis virus were characterized. Evidence was obtained for the presence of temperature-sensitive mutants in the A. dorsalis and C. tarsalis persistently infected cultures, and small plaque mutants were predominant in all cultures except one of two cell cultures of C. tarsalis. Virus from persistently infected A. albopictus cell cultures was growth-restricted in Vero and C. tarsalis cells. One of two persistently infected A. dorsalis cell cultures also produced viral mutants that were growth-restricted in C. tarsalis cells. Further, Western blots of persistently infected A. albopictus cell extracts showed an overproduction of capsid (C) and envelope (E) structural proteins and reduced production of an Mr 27K protein (p27) which was immunologically related to the E protein. In contrast, the production of E and C proteins in persistently infected C. tarsalis cultures was consistent with the amount of infectious virus present, whereas p27 was relatively overproduced. These observations suggest that the host cell has an important influence on both the types and relative quantities of viral mutants that accumulate during long-term persistent infections.

Aedes↗
PubMed1989

Coevolution of virulent virus and resistant cells as a mechanism of persistence of herpes simplex virus type 1 in a human T lymphoblastoid cell line.

Infection of the lymphoblastoid CEM cell line with herpes simplex virus (HSV) type 1 results in a persistent infection with production of infectious virus. Evidence suggests that the persistent infection was not maintained by interferon or non-interferon-soluble antiviral inhibitors. Treatment of persistently infected cells with anti-HSV serum (termed CEMACR cells) or elevated temperature (39 degrees C) for 14 days (termed CEMTCR cells) resulted in loss of evidence of virus. HSV DNA was not detected in CEMACR or CEMTCR cells by Southern blot or in situ hybridization. The CEMACR or CEMTCR cells, however, were resistant to reinfection with homologous, parental virus (HSV0), but were susceptible to heterologous virus (vesicular stomatitis virus). Resistance to reinfection with HSV was not absolute; CEMACR or CEMTCR cells were less permissive to virus isolated from persistently infected cultures at times early in the course of infection, but were more permissive for HSV isolated at later times. Virus isolated later during persistent infection also displayed progressively increased virulence for the parental CEM cells. These results suggest that persistent infection of a human T lymphoblastoid cell line, CEM, with HSV-1 is maintained by a genetically determined cell-virus equilibrium, in which the resistance of cells and virulence of virus increase during persistence.

Animals↗
PubMed2025

Strain-level differences in Gardnerella urinary tract persistence and pathogenesis are consistent with comparative phylogenomic analyses.

BACKGROUND: Gardnerella is a genus of gram variable anaerobic bacteria that is commonly present in the female urogenital tract, especially during bacterial vaginosis (BV). BV is linked with increased risk of urinary tract infections (UTI) and Gardnerella has been frequently detected in urine collected directly from the bladder. Understanding the contribution of Gardnerella to urogenital pathogenesis has been complicated by its genetic heterogeneity and a shortage of data from in vivo models. Recently, a clinical isolate of Gardnerella displayed covert pathogenesis in a mouse urinary tract inoculation model, triggering urothelial exfoliation and promoting UTI by uropathogenic E. coli. Data from clinical studies suggests differential association of Gardnerella phylogenetic clades with BV or urogenital infections. In vitro data has demonstrated heterogeneity in the presence and expression of putative virulence determinants between Gardnerella strains. This study was designed to compare diverse Gardnerella strains in vivo to identify genomic variation associated with urinary tract persistence and pathogenesis. METHODS: Eighteen Gardnerella clinical isolates from each of the four main phylogenetic clades were individually inoculated transurethrally into female C57BL/6 mice. Bacteriuria was monitored by quantitative culturing of Gardnerella in urine. Pathologic features were assessed by immunofluorescent and histological staining of bladder tissues. Pan-genome phylogenetic analyses were performed on the 18 Gardnerella isolates used for mouse infections to identify accessory genes that were associated with observable in vivo phenotypes, including long and short-term persistence, urothelial exfoliation and bladder edema. Genes that were significantly associated to phenotype were then matched against a pangenome analysis of 291 publicly available Gardnerella genomes to determine the conservation of these putative colonization and virulence factors across the genus. RESULTS: Gardnerella strains displayed clear differences in persistence and pathogenesis in the mouse bladder that were congruent with phylogeny. Clade 2 strains were more persistent in the urinary tract whereas strains from the other three clades either caused transient bacteriuria or were undetectable. Strains from clade 2 and 4 induced urothelial exfoliation while edema was triggered by strains from clades 2, 3 and 4. Pangenome analyses revealed 45 genes that were associated with in vivo persistence and pathogenicity. Among the wider 291 publicly available genomes, clade 2 strains encoded more of the genes associated with bacteriuria phenotypes compared to strains in the other three clades. Exfoliation-associated genes were present in most clade 4 strains. Clade 3 strains lack most of the in vivo-associated genes, whereas clade 1 strains were more heterogenous. CONCLUSIONS: This study provides in vivo evidence for differential urinary tract colonization and pathogenesis by strains from different clades/species within the genus Gardnerella and identifies new putative persistence and virulence factors. Utilizing the in vivo data from tested strains, pangenome analyses predicts that clade 2 Gardnerella are the most likely to persist in the urinary tract and that clades 2 and 4 have the highest uropathogenic potential. These findings inform future targeted screening and treatment approaches aimed at limiting harmful Gardnerella urinary tract exposures.

Journal Article↗
PubMed2003

Persistence in q-state Potts model: a mean-field approach.

We study the persistence properties of the T=0 coarsening dynamics of one-dimensional q-state Potts model using a modified mean-field approximation (MMFA). In this approximation, the spatial correlations between the interfaces separating spins with different Potts states is ignored, but the correct time dependence of the mean density P(t) of persistent spins is imposed. For this model, it is known that P(t) follows a power-law decay with time, P(t) approximately t(-theta(q)), where theta(q) is the q-dependent persistence exponent. We study the spatial structure of the persistent region within the MMFA. We show that the persistent site pair correlation function P2(r,t) has the scaling form P2(r,t)=P(t)(2)f(r/t(1/2)) for all values of the persistence exponent theta(q). The scaling function has the limiting behavior f(x) approximately x(-2theta) (x<<1) and f(x)-->1 (x>>1). We then show within the independent interval approximation (IIA) that the distribution n(k,t) of separation k between two consecutive persistent spins at time t has the asymptotic scaling form n(k,t)=t(-2phi)g(t,k/t(phi)), where the dynamical exponent has the form phi=max(1/2,theta). The behavior of the scaling function for large and small values of the arguments is found analytically. We find that for small separations k< >t(phi), g(t,x) decays exponentially with x. The unusual dynamical scaling form and the behavior of the scaling function is supported by numerical simulations.

Journal Article↗