A point-of-care microfluidic biosensing system for rapid and ultrasensitive nucleic acid detection from clinical samples

Rapid and ultrasensitive point-of-care RNA detection plays a critical role in the diagnosis and management of various infectious diseases. The gold-standard detection method of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is ultrasensitive and accurate yet limited by the lengthy turnaround time (1-2 days). On the other hand, an antigen test offers rapid at-home detection (typically ~15 min) but suffers from low sensitivity and high false-negative rates. An ideal point-of-care diagnostic device would combine the merits of PCR-level sensitivity and rapid sample-to-result workflow comparable to antigen testing. However, the existing detection platforms typically possess superior sensitivity or rapid sample-to-result time, but not both. This paper reports a point-of-care microfluidic device that offers ultrasensitive yet rapid detection of viral RNA from clinical samples. The device consists of a microfluidic chip for precisely manipulating small volumes of samples, a miniaturized heater for viral lysis and ribonuclease inactivation, a Cas13a-electrochemical sensor for target preamplification-free and ultrasensitive RNA detection, and a smartphone-compatible potentiostat for data acquisition. As demonstrations, the devices achieve the detection of heat-inactivated SARS-CoV-2 samples with a limit of detection down to 10 aM within 25 minutes, which is comparable to the sensitivity of RT-PCR and rapidness of an antigen test. The platform also successfully distinguishes all nine positive unprocessed clinical SARS-CoV-2 nasopharyngeal swab samples from four negative samples within 25 minutes of sample-to-result time. Together, this device provides a point-of-care solution that can be deployed in diverse settings beyond laboratory environments for rapid and accurate detection of RNA from clinical samples. The device can potentially be expandable to detect other viral targets, such as human immunodeficiency virus self-testing and Zika virus, where rapid and ultrasensitive point-of-care detection is required.

Engineered LwaCas13a with enhanced collateral activity for nucleic acid detection

Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 13 (Cas13) has been rapidly developed for nucleic-acid-based diagnostics by using its characteristic collateral activity. Despite the recent progress in optimizing the Cas13 system for the detection of nucleic acids, engineering Cas13 protein with enhanced collateral activity has been challenging, mostly because of its complex structural dynamics. Here we successfully employed a novel strategy to engineer the Leptotrichia wadei (Lwa)Cas13a by inserting different RNA-binding domains into a unique active-site-proximal loop within its higher eukaryotes and prokaryotes nucleotide-binding domain. Two LwaCas13a variants showed enhanced collateral activity and improved sensitivity over the wild type in various buffer conditions. By combining with an electrochemical method, our variants detected the SARS-CoV-2 genome at attomolar concentrations from both inactive viral and unextracted clinical samples, without target preamplification. Our engineered LwaCas13a enzymes with enhanced collateral activity are ready to be integrated into other Cas13a-based platforms for ultrasensitive detection of nucleic acids.

Development of a Psychometric Tool to Measure Community Solidarity Among Sexual Minorities: Evidence From a Pay-it-Forward Randomized Controlled Trial

BACKGROUND

Community solidarity is increasingly important in public health. However, few studies have examined solidarity in relation to health outcomes. The purpose of this study was to develop a psychometric tool to measure solidarity among Chinese men who have sex with men (MSM) and assess whether community solidarity relates to differences in sexually transmitted infection testing.

METHODS

We used data from the pay-it-forward randomized controlled trial of 301 men from Beijing and Guangzhou, China. Men who have sex with men were randomized into pay-it-forward (participants receive free gonorrhea/chlamydia testing as gifts and choose to donate toward subsequent MSM's tests), pay-what you-want, and standard payment arms. After testing decision, participants completed a cross-sectional questionnaire to assess community solidarity. Factor analysis was conducted to identify dimensions of solidarity. The solidarity factors were compared across study arms and assessed against gonorrhea/chlamydia test uptake in multivariable logistic regression.

RESULTS

Two hundred eighty-eight participants responded to the survey. We identified 3 latent community solidarity factors: engagement, social network support, and sense of belonging. Several items related to belonging were significantly greater among participants in the pay-it-forward scenario compared with those assigned to other scenarios. Higher sense of belonging was associated with higher odds of gonorrhea and chlamydia test uptake.

CONCLUSIONS

Community solidarity among MSM in China can be characterized by 3 factors: engagement, social network support, and sense of belonging. Sense of belonging was higher in the pay-it-forward intervention arm and may be associated with the uptake of gonorrhea/chlamydia test. Future studies are warranted to confirm the psychometric structure of community solidarity and further investigate behavioral mechanisms of pay it forward.

Amplification-Free Detection of SARS-CoV-2 and Respiratory Syncytial Virus Using CRISPR Cas13a and Graphene Field-Effect Transistors

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated (Cas) systems have recently received notable attention for their applications in nucleic acid detection. Despite many attempts, the majority of current CRISPR‐based biosensors in infectious respiratory disease diagnostic applications still require target preamplifications. This study reports a new biosensor for amplification‐free nucleic acid detection via harnessing the trans‐cleavage mechanism of Cas13a and ultrasensitive graphene field‐effect transistors (gFETs). CRISPR Cas13a‐gFET achieves the detection of SARS‐CoV‐2 and respiratory syncytial virus (RSV) genome down to 1 attomolar without target preamplifications. Additionally, we validate the detection performance using clinical SARS‐CoV‐2 samples, including those with low viral loads (Ct value >30). Overall, these findings establish our CRISPR Cas13a‐gFET among the most sensitive amplification‐free nucleic acid diagnostic platforms to date.

Modeling HIV Transmission from Sexually Active Alcohol-Consuming Men in ART Programs to Seronegative Wives

BACKGROUND

The rollout of antiviral therapy in Low and Middle Income Countries (LMICs) has reduced HIV transmission rates at the potential risk of resistant HIV transmission. We sought to predict the risk of wild type and antiviral resistance transmissions in these settings.

METHODS

A predictive model utilizing viral load, ART adherence, genital ulcer disease, condom use, and sexual event histories was developed to predict risks of HIV transmission to wives of 233 HIV+ men in 4 antiretroviral treatment centers in Maharashtra, India.

RESULTS

ARV Therapy predicted a 5.71-fold reduction in transmissions compared to a model of using condoms alone, with 79.9%, of remaining transmissions resulting in primary ART-resistance.

CONCLUSIONS

ART programs reduce transmission of HIV to susceptible partners at a substantial increased risk for transmission of resistant virus. Enhanced vigilance in monitoring adherence, use of barrier protections, and viral load may reduce risks of resistant HIV transmissions in LMIC settings.

Human Brucellosis in Rural Uganda: Clinical Manifestations, Diagnosis, and Comorbidities at Kabale Regional Referral Hospital, Kabale, Uganda

Background

Brucellosis is a zoonotic infection transmitted to humans through direct contact with infected animals, their products, or excreta such as urine or dung. Brucellosis is associated with significant morbidity in Southwestern Uganda, where cattle and goat rearing are a major economic industry. As in many settings in sub-Saharan Africa, diagnosis and management of brucellosis remain a challenge due to the presence of comorbidities and limitations in resources for diagnostic testing and therapy.

Methods

A chart review was conducted to characterize the clinical manifestations, diagnosis, comorbidities, and management of 101 patients treated for brucellosis at the Kabale Regional Referral Hospital from September 2002 to May 2010.

Results

Patients presented with substantial comorbidities. The most common manifestation of illness was osteoarticular, but disease manifestations were quite varied. A high rate of focal illness in this cohort (77%) was observed.

Conclusions

Clinicians in this setting should be cognizant of the varied presentations, comorbidities, and treatment options for this disease.

Factors affecting patient presentation at a national dermatology referral clinic in Kampala, Uganda

BACKGROUND

This study sought to gain a better understanding of the patient population in Kampala and was further designed to elucidate barriers that may delay individuals from receiving proper dermatologic care.

METHODS

The study took place at the dermatovenereology clinic of a tertiary care hospital in Kampala. New adult patients were surveyed in July and August of 2013. The primary dependent variable was time from reported onset of symptoms to presentation to the clinic. Participant demographic characteristics, medical and treatment history, and perception of illness as measured by the dermatology life quality index (DLQI) were assessed.

RESULTS

A total of 232 subjects participated in the study. The most common skin diseases were allergic (20.3%), infectious (15.1%), follicular (7.8%), and papulosquamous (7.8%) disorders. Greater home distance from the clinic correlated with later presentation times (r = 0.259, P < 0.001). DLQI score was not correlated with presentation time. HIV+ individuals presented earlier (mean 5 vs. 11 months, P = 0.043) and had higher DLQI scores (mean 12.6 vs. 9.3, P = 0.006) than HIV- individuals. The majority of participants (72.5%) had contact with at least one other healthcare worker (HCW) for management of their dermatologic symptoms; 65.8% reported that these previous treatments were ineffective.

CONCLUSIONS

Efforts to educate HCWs should be focused on districts outside of Kampala and highlight recognition and proper treatment of allergic diseases. HCWs should aggressively treat skin problems in HIV+ individuals. HCWs practicing in Kampala without formal dermatological training should refer patients with skin disease to the clinic, as patients may receive care that is more appropriate.

The Addition of High-Risk HPV Testing to Anal Cytology Increases the Identification of Anal Dysplasia in HIV-Infected Patients

BACKGROUND

Anal dysplasia (AD) is prevalent in HIV-infected patients. Screening for AD is recommended for high-risk groups, including HIV-infected patients. We evaluated screening algorithms for AD using cytology, high-risk human papillomavirus (HRH) testing, or both.

METHODS

HIV-infected patients were offered AD screening by both anal cytology and PCR-based detection of HRH. Patients with abnormal cytology (AC) or HRH genotypes were referred to the same oncologic surgeon for high-resolution anoscopy (HRA).

RESULTS

Ninety patients underwent screening (84% men who have sex with men). Forty-four patients (52.6%) had abnormal screens (31.5% AC, 46% HRH). Twenty-six patients with AC and/or positive HRH had HRA. AC and nadir CD4+ cell count of < 200 cells/mm3 were predictors of abnormal histology on HRA by univariate analysis (OR 4.5 and 2.5, respectively). Using a log-linear model, we estimated that for every 49 cases with two normal screening tests, one case of AD would be missed. Conclusions: Universal screening for AD in an HIV+ population yielded a high percentage of abnormal findings. Addition of HRH to cytology screening increased positive screens by 24%. Larger studies are needed to determine the ideal screening method.

Proactive infectious disease approach to dermatologic patients who are taking tumor necrosis factor-alfa antagonists: Part II. Screening for patients on tumor necrosis factor-alfa antagonists

Tumor necrosis factor-alfa levels are linked to disease severity in patients with inflammatory conditions, such as psoriasis. Inhibitors of this cytokine are commonly used with significant success in the treatment of such inflammatory disorders. Their use, however, can be plagued by infectious complications. An awareness of potential infections associated with these therapies is critical in order to maximize preventive efforts both before and during therapy. This review provides a guide for dermatologists caring for patients in need of this type of biologic therapy to preemptively address the infectious risks. Part II of this continuing medical education article reviews recommended screening methods for patients undergoing evaluations for tumor necrosis factor inhibitor therapy for psoriasis or other dermatologic diseases, and discusses possible prophylactic strategies to use, including the appropriate use of immunizations.

Outcomes of a multifaceted medication adherence intervention for HIV-positive patients

Treatment of HIV infection with highly active antiretroviral therapy (HAART) requires high levels of adherence in order to obtain maximum benefit and minimize the development of antiviral resistance. Many patients in community clinical settings have imperfect adherence that may lead to poor clinical outcomes. The Connecticut HIV Medication Project (CHaMP) is a multidisciplinary program designed to evaluate patients receiving antiviral therapy. Based on results of a multifaceted assessment, a variety of targeted interventions and follow-up are offered. A retrospective analysis was performed on patients who were referred to the program over a 35-month period from March 2002 through January 2005. Two hundred forty-nine patients who were referred for adherence services had baseline and follow-up data available for analysis. Participants who maintained an unchanged antiretroviral regimen experienced a significant increase in self-reported adherence (89.1% to 96.9%, p < 0.001) and likelihood of reporting more than 95% adherence (36.6% to 73.1%, p < 0.001) by 7-day recall. Improvements in plasma HIV viremia (3.10 +/- 1.21 log copies to 2.78 +/- 0.98, p < 0.01) were also demonstrated. Limitations to this study included the unusually high level of baseline adherence, the large fraction of patients (28.6%) who were lost to follow-up, and follow-up that was limited to one time point at 12-16 weeks such that attrition of the intervention effect could not be assessed. The CHaMP experience demonstrates that the development of a multifaceted clinical program can have significant impact on medication adherence and viral burden in HIV infection.

Home Visits to Improve Adherence to Highly Active Antiretroviral Therapy

BACKGROUND

Few rigorously designed studies have documented the efficacy of interventions to improve medication adherence among patients prescribed highly active antiretroviral. Data are needed to justify the use of limited resources for these programs.

METHODS

A 2-arm, randomized, controlled trial evaluated the efficacy of a community-based, home-visit intervention to improve medication adherence. Participants were 171 HIV-infected adults prescribed a minimum of 3 antiretroviral agents. The majority had a past or current history of substance abuse. Subjects were randomly assigned to receive home visits for 1 year or usual care. Medication adherence was assessed with Medication Event Monitoring stem caps at 3-month intervals from randomization through 3 months after the conclusion of the intervention.

RESULTS

A larger proportion of subjects in the intervention group demonstrated adherence greater than 90% compared with the control group at each time point after baseline. The difference over time was statistically significant (Extended Mantel-Haenszel test: 5.80, P = 0.02). A statistically significant intervention effect on HIV-RNA level or CD4 cell count was not seen, but there was a statistically significant association between greater than 90% adherence and an undetectable HIV-RNA over time (P < 0.03).

CONCLUSION

Home visits from a nurse and a community worker were associated with medication adherence greater than 90% among a cohort of socially vulnerable people living with HIV/AIDS in northeastern United States.

Use of electronic monitoring devices to measure antiretroviral adherence: practical considerations

The purpose of this paper is to describe electronic monitoring device (EMD) (e.g., MEMS caps) use among HIV-infected adults enrolled in a randomized clinical trial and to make explicit some of the benefits and caveats of using electronic monitoring device technology. This is a descriptive, exploratory study of EMD use among 128 HIV-infected adults treated with at least three antiretroviral agents. Thirty-six percent of the sample admitted that they did not use the EMD consistently. Forty-one percent of the subjects reported taking out more than one dose at a time and 26% reported opening the EMD but not taking the medication. Special subject-related issues accounted for only a small percentage of all reported problems with EMD use (e.g., transient housing, incarceration, substance abuse relapse and drug treatment). Results of this study suggest that EMDs may underestimate antiretroviral adherence among HIV-infected adults. Recommendations for improving EMD data quality are presented.

Effects of illicit drug use on adherence to prescribed antiretroviral medication

This exploratory analysis compared adherence to antiretroviral medication on days that illicit drugs were used and on matched abstinence days in twelve subjects who used MEMS caps during participation in a clinical trial. Adherence on drug use days was lower in seven subjects, higher in one, and the same in four. Three subjects maintained 100% adherence despite illicit substance use on studied days. Thus, in a subset of patients, the actions involved in procuring drugs and the acute effects of using them contribute to non-adherence on those specific drug use days, associated with substance abuse. (Am J Addict 2003;12:455-458)

Cue-dose training with monetary reinforcement: pilot study of an antiretroviral adherence intervention

OBJECTIVE

To assess the feasibility and efficacy of two interventions for improving adherence to antiretroviral therapy regimens in HIV-infected subjects compared with a control intervention.

DESIGN

Randomized, controlled, pilot study.

SETTING

Department of Veterans Affairs HIV clinic and community-based HIV clinical trials site.

PARTICIPANTS

Fifty-five HIV-infected subjects on stable antiretroviral therapy regimens. Subjects were predominantly male (89%) and African American (69%), and had histories of heroin or cocaine use (80%).

INTERVENTIONS

Four weekly sessions of either nondirective inquiries about adherence (control group, C), cue-dose training, which consisted of the use of personalized cues for remembering particular dose times, and feedback about medication taking using Medication Event Monitoring System (MEMS) pill bottle caps, which record time of bottle opening (CD group), or cue-dose training combined with cash reinforcement for correctly timed bottle opening (CD+CR).

MEASUREMENTS

Opening of the pill bottle within 2 hours before or after a predetermined time was measured by MEMS.

RESULTS

Adherence to the medication as documented by MEMS was significantly enhanced during the 4-week training period in the CD+CR group, but not in the CD group, compared with the control group. Improvement was also seen in adherence to antiretroviral drugs that were not the object of training and reinforcement. Eight weeks after training and reinforcement were discontinued, adherence in the cash-reinforced group returned to near-baseline levels.

CONCLUSIONS

Cue-dose training with cash reinforcement led to transient improvement in adherence to antiretroviral therapy in a population including mostly African Americans and subjects with histories of drug abuse. However, we were not able to detect any sustained improvement beyond the active training period, and questions concerning the timing and duration of such an intervention require further study. Randomized, controlled clinical studies with objective measures of adherence can be conducted in HIV-infected subjects and should be employed for further evaluation of this and other adherence interventions.

Infection control concepts in critical care

Patients with critical illnesses requiring aggressive medical intervention are at risk of acquiring serious nosocomial infection that may lead to increases in medical expenditures, morbidity, and mortality. Infection control in this population entails continuous surveillance for hospital-acquired infection, with investigation of outbreaks. Policies for effective antibiotic utilization, disinfection of medical devices and hospital environment, and patient isolation may limit nosocomial infection in this population. Finally, an effective infection control program should protect the health care worker from hospital-acquired infections through educational programs, routine health surveillance, vaccinations, and post-exposure care.