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Pathogens (Basel, Switzerland) Feb 2022is a commensal fungus that asymptomatically colonizes the skin and mucosa of 60% of healthy individuals. Breaches in the cutaneous and mucosal barriers trigger... (Review)
Review
is a commensal fungus that asymptomatically colonizes the skin and mucosa of 60% of healthy individuals. Breaches in the cutaneous and mucosal barriers trigger candidiasis that ranges from asymptomatic candidemia and mucosal infections to fulminant sepsis with 70% mortality rates. Fungi influence at least several diseases, in part by mechanisms such as the production of pro-carcinogenic agents, molecular mimicking, and triggering of the inflammation cascade. These processes impact the interactions among human pathogenic and resident fungi, the bacteriome in various organs/tissues, and the host immune system, dictating the outcomes of invasive infections, metabolic diseases, and cancer. Although mechanistic investigations are at stages of infancy, recent studies have advanced our understanding of host-fungal interactions, their role in immune homeostasis, and their associated pathologies. This review summarizes the role of and other opportunistic fungi, specifically their association with various diseases, providing a glimpse at the recent developments and our current knowledge in the context of inflammatory-bowel disease (IBD), cancers, and COVID-19. Two of the most common human diseases where fungal interactions have been previously well-studied are cancer and IBD. Here we also discuss the emerging role of fungi in the ongoing and evolving pandemic of COVID-19, as it is relevant to current health affairs.
PubMed: 35215155
DOI: 10.3390/pathogens11020212 -
Sexually Transmitted Infections Jun 2020Although rapid screening and treatment programmes have been recently implemented to tackle STIs, testing (MG) among asymptomatic populations is not currently...
OBJECTIVES
Although rapid screening and treatment programmes have been recently implemented to tackle STIs, testing (MG) among asymptomatic populations is not currently recommended due to the lack of scientific evidence and the emergence of antibiotic resistance. The main objective of this study was to estimate the prevalence of MG and macrolide resistance among asymptomatic people visiting a point of care service for rapid STI screening and to identify risk factors associated with the acquisition of this infection.
METHODS
Between October 2017 and January 2018, a total of 890 asymptomatic individuals attending to the STI screening service Drassanes Exprés in Barcelona, Spain, were tested for MG and macrolide resistance using the molecular ResistancePlus MG assay (SpeeDx, Australia). Asymptomatically infected individuals were invited to attend the STI Unit for resistance-guided antimicrobial therapy.
RESULTS
Overall, the prevalence of MG was 7.4% (66/890; 95% CI 5.8% to 9.3%), being higher among men who have sex with men (MSM) (46/489) compared with heterosexual men and women (20/401; p=0.012). Macrolide resistance was found in 32/46 (69.6%; 95% CI 54.2% to 82.3%) MSM, while only 2/20 (10.0%; 95% CI 1.2% to 31.7%) infections among heterosexuals presented macrolide resistance-mediated mutations (p<0.001). MSM behaviour, receptive anal intercourse, HIV positive status, syphilis history and high-risk sexual activity (more than five sexual partners in the last 3 months) were significantly associated with MG infection. Furthermore, the resistance-guided therapy approach was implemented in 36/66 (54.6%) individuals.
CONCLUSIONS
The research provides further data regarding the prevalence of MG and macrolide resistance among asymptomatic individuals. It also identifies higher risk subpopulations which might be targets for MG screening. Nevertheless, there is insufficient data to justify MG testing among asymptomatic individuals and current STI guidelines should be followed until evidence shows the cost and effectiveness of screening.
Topics: Adult; Anti-Bacterial Agents; Asymptomatic Diseases; Cross-Sectional Studies; Drug Resistance, Bacterial; Female; Humans; Macrolides; Male; Mycoplasma Infections; Mycoplasma genitalium; Prevalence; Risk Factors; Spain
PubMed: 31451540
DOI: 10.1136/sextrans-2019-054124 -
JAMA Jan 1990Twenty-seven women with recurrent genital herpes simplex virus infection underwent daily home culturing to detect asymptomatic genital herpes simplex virus shedding....
Twenty-seven women with recurrent genital herpes simplex virus infection underwent daily home culturing to detect asymptomatic genital herpes simplex virus shedding. Asymptomatic herpes simplex virus shedding was documented on 1% of the days on which cultures were obtained. Asymptomatic shedding from the vulva was as frequent as asymptomatic cervicovaginal shedding, and 45% of asymptomatic episodes were identified only by positive results from vulvar cultures. All women who obtained samples on more than 100 days and 80% of women who obtained samples on more than 50 days had documented asymptomatic viral shedding, compared with only 6% of those who obtained samples for fewer than 25 days. Asymptomatic shedding was not related to contraceptive use or menstrual cycle. These data suggest that all women with recurrent genital herpes simplex virus infection should be instructed about the possible risk, albeit infrequent, of asymptomatically shedding virus from the genital tract.
Topics: Adult; Cervix Uteri; Cohort Studies; Female; Genitalia, Female; Herpes Genitalis; Humans; Middle Aged; Recurrence; Simplexvirus; Specimen Handling; Vagina
PubMed: 2152951
DOI: No ID Found -
Mathematical Biosciences Jun 2017In this paper, we introduce a malaria model with an asymptomatic class in human population and exposed classes in both human and vector populations. The model assumes...
In this paper, we introduce a malaria model with an asymptomatic class in human population and exposed classes in both human and vector populations. The model assumes that asymptomatic individuals can get re-infected and move to the symptomatic class. In the case of an incomplete treatment, symptomatic individuals move to the asymptomatic class. If successfully treated, the symptomatic individuals recover and move to the susceptible class. The basic reproduction number, R, is computed using the next generation approach. The system has a disease-free equilibrium (DFE) which is locally asymptomatically stable when R<1, and may have up to four endemic equilibria. The model exhibits backward bifurcation generated by two mechanisms; standard incidence and superinfection. If the model does not allow for superinfection or deaths due to the disease, then DFE is globally stable which suggests that backward bifurcation is no longer possible. Simulations suggest that total prevalence of malaria is the highest if all individuals show symptoms upon infection, but then undergoes an incomplete treatment and the lowest when all the individuals first move to the symptomatic class then treated successfully. Total prevalence is average if more individuals upon infection move to the asymptomatic class. We study optimal control strategies applied to bed-net use and treatment as main tools for reducing the total number of symptomatic and asymptomatic individuals. Simulations suggest that the optimal control strategies are very dynamic. Although they always lead to decrease in the symptomatic infectious individuals, they may lead to increase in the number of asymptomatic infectious individuals. This last scenario occurs if a large portion of newly infected individuals move to the symptomatic class but many of them do not complete treatment or if they all complete treatment but the superinfection rate of asymptomatic individuals is average.
Topics: Asymptomatic Infections; Basic Reproduction Number; Humans; Incidence; Malaria; Models, Biological; Prevalence; Superinfection
PubMed: 28284964
DOI: 10.1016/j.mbs.2017.03.003 -
The Journal of Hospital Infection Jun 2019Estimates of the prevalence of asymptomatically carried Clostridium difficile in elderly patients in long-term care range from 0% to 51%. Asymptomatic carriage is...
BACKGROUND
Estimates of the prevalence of asymptomatically carried Clostridium difficile in elderly patients in long-term care range from 0% to 51%. Asymptomatic carriage is possibly a risk factor for the development of infection, and there is ongoing debate surrounding the role of asymptomatic carriage in transmission.
AIM
To investigate the prevalence of asymptomatic carriage amongst patients residing in intermediate care (bedded) facilities (ICBFs), and to investigate whether asymptomatically carried C. difficile strains contribute to nosocomial C. difficile infection (CDI).
METHODS
Stools were collected from eligible asymptomatic patients in ICBFs, and a subset was also processed from symptomatic patients accessing primary or secondary care outside of ICBFs. All samples were cultured for C. difficile, and resulting colonies were processed through whole genome sequencing.
FINDINGS
In total, 151 asymptomatic patients were sampled, 22 of which were positive for C. difficile through stool culture, representing a carriage rate of 14.6%. Sequencing of these isolates, alongside 14 C. difficile polymerase chain reaction and culture-positive isolates from symptomatic individuals, revealed that all asymptomatic patients were carrying toxigenic C. difficile, and these strains were genetically similar to those from symptomatic patients.
CONCLUSION
This small study of asymptomatic carriage revealed a rectal asymptomatic carriage rate of 14.6% in patients nursed in ICBFs, and a high level of genetic similarity of these strains to those recovered from symptomatic patients. As such, asymptomatic carriers may be important for the transmission of symptomatic CDI, although it is acknowledged that this study was small, and many other factors govern whether C. difficile is carried asymptomatically or causes symptoms.
Topics: Aged; Aged, 80 and over; Bacteriological Techniques; Carrier State; Clostridioides difficile; Clostridium Infections; Cross Infection; Disease Transmission, Infectious; Feces; Female; Genome, Bacterial; Humans; Long-Term Care; Male; Molecular Epidemiology; Prevalence; Whole Genome Sequencing
PubMed: 30359648
DOI: 10.1016/j.jhin.2018.10.012 -
The Indian Journal of Radiology &... Jan 2021With COVID-19 cases rising, despite CT chest being of value in diagnosis and prognostication in COVID-19, its role in mild or asymptomatic suspected COVID-19, before...
Demographic and clinico-radiological profile on High-Resolution Computerized Tomography (HRCT) thorax in mild or asymptomatic clinically suspected COVID-19 patients in high-endemicity area of India-Can HRCT be the first screening tool? -The DECRYPTION study.
BACKGROUND
With COVID-19 cases rising, despite CT chest being of value in diagnosis and prognostication in COVID-19, its role in mild or asymptomatic suspected COVID-19, before RT-PCR test is lacking.
METHOD
This is a retrospective observational study involving asymptomatic or mildly symptomatic clinically suspected COVID-19 infection in a high endemicity area. Of 2532 HRCT chest database, 376 eligible cases were analyzed for clinico-radiological correlation for CT findings based CORADS and CT severity score between positive vs negative group.
RESULTS
Of 376, 186 (48.46%) had COVID-19 features on HRCT in mild and asymptomatic suspected patients. 98 (26.06%) had CO-RARDS - 5, 88 (23.40%) had CO-RADS - 4. 48 (12.76%), 128 (34.04%), 14 (3.72%) had CO-RADS score of 3,2,1, respectively. Positive CT findings were more likely beyond 3 days of symptoms compared to those presenting earlier {days: (Mean) 4.2 vs 2.76} Positive CT was significantly associated with patients with anosmia and dyspnea. The common presenting symptoms were Fever 196 (52.12%) and followed by sore throat in 173 (46.01%). The common HRCT findings were Ground glass opacity (GGO) (74.60%), followed by Lymphadenopathy (LN) (27.92%). LN which was more prevalent in symptomatic patients {99/343 (28.86%) vs {6/33 (18.18%)} asymptomatics (: 0.04)}. Consolidation was significantly more in asymptomatics with COPD (: 0.004). 6 (3.22%) patients had CT score >17/25.
CONCLUSION
Chest HRCT picked 48.46% positive cases in mildly symptomatic and asymptomatic patients of which 3.22% had severe involvement (>17). Being a noninvasive, rapid, sensitive, low risk of cross infection with high reproducibility, chest CT is worth evaluating as screening modality even in asymptomatic and mildly symptomatic clinically suspected COVID-19.
PubMed: 33814771
DOI: 10.4103/ijri.IJRI_796_20 -
Infection and Immunity Jan 2006Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic... (Comparative Study)
Comparative Study
Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract. The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. Deliberate colonization of UTI-susceptible individuals with E. coli 83972 has been used successfully as an alternative approach for the treatment of patients who are refractory to conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human urine and show that it can outcompete a representative spectrum of UPEC strains for growth in urine. The unique ability of ABU E. coli 83972 to outcompete UPEC in urine was also demonstrated in a murine model of human UTI, confirming the selective advantage over UPEC in vivo. Comparison of global gene expression profiles of E. coli 83972 grown in lab medium and human urine revealed significant differences in expression levels in the two media; significant down-regulation of genes encoding virulence factors such as hemolysin, lipid A, and capsular polysaccharides was observed in cells grown in urine. Clearly, divergent abilities of ABU E. coli and UPEC to exploit human urine as a niche for persistence and survival suggest that these key differences may be exploited for preventative and/or therapeutic approaches.
Topics: Adhesins, Bacterial; Animals; Bacteriuria; Carbohydrate Metabolism; Disease Models, Animal; Escherichia coli; Female; Gene Expression; Humans; Iron; Male; Mice; Mice, Inbred CBA; Oligonucleotide Array Sequence Analysis; Species Specificity; Urinary Bladder; Urinary Tract Infections; Virulence Factors
PubMed: 16369018
DOI: 10.1128/IAI.74.1.615-624.2006 -
Research and Practice in Thrombosis and... Mar 2024Managing central venous catheters in patients with neoplasms is challenging, and peripherally inserted central catheter PORT (PICC-PORT) has emerged as a promising...
Incidence and clinical progression of asymptomatic peripherally inserted central catheterrelated thrombosis in solid neoplasm patients: ultrasound insights from a prospective cohort study.
BACKGROUND
Managing central venous catheters in patients with neoplasms is challenging, and peripherally inserted central catheter PORT (PICC-PORT) has emerged as a promising option for safety and efficacy. However, understanding the clinical progression of catheter-related thrombosis (CRT) in cancer patients with central venous catheters remains limited, especially in certain neoplasm types associated with a higher risk of venous thrombosis.
OBJECTIVES
This study aims to assess the effectiveness of ultrasound-guided management in detecting and treating asymptomatic CRT in cancer patients with PICC.
METHODS
In this prospective cohort study of 120 patients with solid neoplasms receiving chemotherapy, we investigated the incidence of isolated upper-extremity superficial vein thrombosis, upper-extremity deep vein thrombosis, and fibrin sheath formation through ultrasound follow-up at 30 and 90 days after catheter insertion. We analyzed risk factors associated with CRT and compared incidence rates between PICC-PORT and traditional PICC.
RESULTS
Among the cohort, 69 patients (57.5%) had high-risk thromboembolic neoplasm, and 31 cases (25.8%) of CRT were observed, mostly within 30 days, with only 7 cases (22.6%) showing symptoms. Traditional PICC use (odds ratio, 5.86; 95% CI, 1.14-30) and high-risk thromboembolic neoplasm (odds ratio, 4.46; 95% CI, 1.26-15.81) were identified as independent risk factors for CRT.
CONCLUSION
The majority of CRT present asymptomatically within the first 30 days of venous catheter insertion in patients with solid neoplasms. Ultrasound follow-up is valuable for detecting asymptomatic CRT. The risk of CRT was lower with PICC-PORT than with PICC. Additionally, the risk of CRT was found to be higher in patients with high-risk thromboembolic neoplasms. It is crucial for larger studies to confirm the utility of treating asymptomatic thromboses and isolated superficial thrombosis.
PubMed: 38660454
DOI: 10.1016/j.rpth.2024.102391 -
Microorganisms Sep 2019Fungi represent a common and diverse part of the microbial communities that associate with plants. They also commonly colonise various plant parts asymptomatically. The...
Fungi represent a common and diverse part of the microbial communities that associate with plants. They also commonly colonise various plant parts asymptomatically. The molecular mechanisms of these interactions are, however, poorly understood. In this study we use transcriptomic data from to demonstrate that RNA-seq data are a neglected source of information to study fungal-host interactions, by exploring the fungal transcripts they inevitably contain. We identified fungal transcripts from data based on their sequence dissimilarity to the genome and predicted biological functions. Taxonomic classifications identified, amongst other fungi, many well-known pathogenic fungal taxa in the asymptomatic tissue of . The comparison of a clone of resistant to with a susceptible clone revealed a significant difference in the number of fungal transcripts, while the number of fungal taxa was not substantially affected. Classifications of transcripts based on their respective biological functions showed that the fungal communities of the two clones associate with fundamental biological processes, with some notable differences. To shield the greater host defence machinery in the resistant clone, fungi produce more secondary metabolites, whereas the environment for fungi associated with the susceptible clone is more conducive for building fungal cellular structures and biomass growth. Secreted proteins included carbohydrate active enzymes that potentially are involved in fungal-plant and fungal-microbe interactions. While plant transcriptome datasets cannot replace the need for designed experiments to probe plant-microbe interactions at a molecular level, they clearly hold potential to add to the understanding of the diversity of plant-microbe interactions.
PubMed: 31547186
DOI: 10.3390/microorganisms7100375 -
Microbiology (Reading, England) Jun 2006Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic...
Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infection (UTI), very little is known about the mechanisms by which these strains colonize the urinary tract. Bacterial adhesion conferred by specific surface-associated adhesins is normally considered as a prerequisite for colonization of the urinary tract. The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. This study characterized the molecular status of one of the primary adhesion factors known to be associated with UTI, namely F1C fimbriae, encoded by the foc gene cluster. F1C fimbriae recognize receptors present in the human kidney and bladder. Expression of the foc genes was found to be up-regulated in human urine. It was also shown that although strain 83972 contains a seemingly intact foc gene cluster, F1C fimbriae are not expressed. Sequencing and genetic complementation revealed that the focD gene, encoding a component of the F1C transport and assembly system, was non-functional, explaining the inability of strain 83972 to express this adhesin. The data imply that E. coli 83972 has lost its ability to express this important colonization factor as a result of host-driven evolution. The ancestor of the strain seems to have been a pyelonephritis strain of phylogenetic group B2. Strain 83972 therefore represents an example of bacterial adaptation from pathogenicity to commensalism through virulence factor loss.
Topics: Agglutination; Amino Acid Substitution; Bacteriuria; Escherichia coli; Escherichia coli Proteins; Female; Fimbriae, Bacterial; Humans; Molecular Sequence Data; Multigene Family; Mutation; Oligonucleotide Array Sequence Analysis; Sequence Analysis, DNA; Urine
PubMed: 16735742
DOI: 10.1099/mic.0.28711-0