Comparative assessment of methicillin resistant Staphylococcus aureus diagnostic assays for use in resource-limited settings

BACKGROUND

The rise of methicillin-resistant Staphylococcus aureus (MRSA) is a global health concern. Paucity of data on MRSA carriage prevalence and diagnostic methods in resource-limited settings hampers efforts to define the problem and plan an appropriate response. Additionally, high variability in cost and logistical characteristics of MRSA screening methods may impede infection control efforts. We compared the performance of locally-available chromogenic agar BD CHROMagar MRSA II and two PCR-based assays (Hain GenoQuick MRSA and Cepheid Xpert SA Complete) for the detection of asymptomatic MRSA carriage in nasal swabs.

RESULTS

During 2015, we enrolled 500 patients from five hospital wards at a Ugandan regional referral hospital. We found 30% prevalence of methicillin-sensitive Staphylococcus aureus (MSSA) nasal carriage, and 5.4% MRSA nasal carriage prevalence. Compared to a composite reference standard defined as a positive test result on any one of the three assays, Hain GenoQuick MRSA demonstrated the highest sensitivity (96%) followed by direct plating on CHROMagar at (70%), with the lowest sensitivity observed with Xpert SA Complete (52%). Cepheid Xpert provided the most rapid results (< 1 h) but was the most expensive (US $45-50/test). Substantially more labor was required for the Hain GenoQuick MRSA compared to Xpert SA Complete or CHROMagar tests.

CONCLUSION

MRSA nasal carriage prevalence rates were low, and high diagnostic sensitivity was achieved using Hain GenoQuick MRSA. Chromogenic media had significantly lower sensitivity, but may represent a viable local option given its lower cost compared to PCR-based assays.

Kerosene lighting contributes to household air pollution in rural Uganda

The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM_2.5 ) from living rooms and kitchens of 88 households in rural Uganda. Linear mixed-effects models with a random intercept for household were used to test the hypotheses that primary reported lighting source and kitchen location (indoor vs outdoor) are associated with PM_2.5 levels. During initial testing, households reported using the following sources of lighting: open-wick kerosene (19.3%), hurricane kerosene (45.5%), battery-powered (33.0%), and solar (1.1%) lamps. During follow-up testing, these proportions changed to 29.5%, 35.2%, 18.2%, and 9.1%, respectively. Average ambient, living room, and kitchen PM_2.5 levels were 20.2, 35.2, and 270.0 μg/m³ . Living rooms using open-wick kerosene lamps had the highest PM_2.5 levels (55.3 μg/m³ ) compared to those using solar lighting (19.4 μg/m³ ; open wick vs solar, P=.01); 27.6% of homes using open-wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting.

Re-inventing adherence: toward a patient-centered model of care for drug-resistant tuberculosis and HIV

BACKGROUND

Despite renewed focus on molecular tuberculosis (TB) diagnostics and new antimycobacterial agents, treatment outcomes for patients co-infected with drug-resistant TB and human immunodeficiency virus (HIV) remain dismal, in part due to lack of focus on medication adherence as part of a patient-centered continuum of care.

OBJECTIVE

To review current barriers to drug-resistant TB-HIV treatment and propose an alternative model to conventional approaches to treatment support.

DISCUSSION

Current national TB control programs rely heavily on directly observed therapy (DOT) as the centerpiece of treatment delivery and adherence support. Medication adherence and care for drug-resistant TB-HIV could be improved by fully implementing team-based patient-centered care, empowering patients through counseling and support, maintaining a rights-based approach while acknowledging the responsibility of health care systems in providing comprehensive care, and prioritizing critical research gaps.

CONCLUSION

It is time to re-invent our understanding of adherence in drug-resistant TB and HIV by focusing attention on the complex clinical, behavioral, social, and structural needs of affected patients and communities.

Prevalence of antiretroviral drug resistance in the HIV-1-infected urban indigent population in San Francisco: a representative study

We determined the prevalence of antiretroviral (ARV) resistance in HIV-1 infected indigent persons in San Francisco, California. Three hundred and twenty-seven subjects (159 (49%) ARV naïve, and 168 (51%) ARV-experienced), were recruited during 1996–97 and 1999–2000. Plasma HIV-1 viral load quantification and genotypic resistance testing were performed. Twice as many subjects received nucleoside reverse transcriptase inhibitors (NRTIs) as non-nucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs); resistance mutation prevalences were 30%, 14% and 16% respectively. Risk of any resistance mutations was strongly and independently associated with prior ARV exposure (OR = 1.3 per year of exposure, P < 0.0001) and with ARV exposure prior to HAART (OR = 2.5, P = 0.015). Prevalences of primary ARV resistance mutations among both treatment-naive and treatment-experienced subjects in this indigent urban population are low compared to other observational cohorts, are directly related to length and type of prior ARV exposure, and did not increase significantly between recruitment periods.

Adherence to HIV antiretroviral therapy in HIV+ Ugandan patients purchasing therapy

Our objective was to determine the level of adherence and reasons for non-adherence to antiretroviral therapy (ART) among HIV-positive (HIV+) people on ART in a resource-limited setting. Patients receiving ART were recruited into the cross-sectional study from three treatment centres in Kampala, Uganda. The number of missed doses over the last three days was assessed by structured patient interviews and dichotomized at ±95% adherence. Reasons for non-adherence were assessed with both structured patient interviews and unstructured qualitative interviews. Independent predictors of non-adherence were assessed with multivariate logistic regression. In all, 304 HIV-infected persons on ART were enrolled into the study. Factors associated with non-adherence were marital status (odds ratio (OR) = 2.93, 95% confidence interval (CI) 1.32–6.50) and low monthly income <50 US&dollar; [OR = 2.77, 95% CI 1.64–4.67]. We concluded that levels of self-reported adherence in patients receiving ART in Kampala are comparable to levels in resource-rich settings with inability to purchase and secure a stable supply as a major barrier to adherence.

Periconception HIV Risk Behavior Among Men and Women Reporting HIV-Serodiscordant Partners in KwaZulu-Natal, South Africa

HIV-infected men and women who choose to conceive risk infecting their partners. To inform safer conception programs we surveyed HIV risk behavior prior to recent pregnancy amongst South African, HIV-infected women (N = 209) and men (N = 82) recruited from antenatal and antiretroviral clinics, respectively, and reporting an uninfected or unknown-HIV-serostatus pregnancy partner. All participants knew their HIV-positive serostatus prior to the referent pregnancy. Only 11 % of women and 5 % of men had planned the pregnancy; 40 % of women and 27 % of men reported serostatus disclosure to their partner before conception. Knowledge of safer conception strategies was low. Around two-thirds reported consistent condom use, 41 % of women and 88 % of men reported antiretroviral therapy, and a third of women reported male partner circumcision prior to the referent pregnancy. Seven women (3 %) and two men (2 %) reported limiting sex without condoms to peak fertility. None reported sperm washing or manual insemination. Safer conception behaviors including HIV-serostatus disclosure, condom use, and ART at the time of conception were not associated with desired pregnancy. In light of low pregnancy planning and HIV-serostatus disclosure, interventions to improve understandings of serodiscordance and motivate mutual HIV-serostatus disclosure and pregnancy planning are necessary first steps before couples or individuals can implement specific safer conception strategies.

Late presentation to HIV/AIDS testing, treatment or continued care: clarifying the use of CD4 evaluation in the consensus definition

OBJECTIVES

Late presentation to HIV/AIDS services compromises treatment outcomes and misses opportunities for biomedical and behavioural prevention. There has been significant heterogeneity in how the term 'late presentation' (LP) has been used in the literature. In 2011, a consensus definition was reached using CD4 counts to define and measure late presenters and, while it is useful for clinical care, the consensus definition has several important limitations that we discuss in this article.

METHODS

Using the spectrum of engagement in HIV care presented by Gardner and colleagues, this article highlights issues and opportunities associated with use of the consensus definition.

RESULTS

The consensus definition is limited by three principal factors: (1) the CD4 count threshold of 350 cells/μL is being increasingly questioned as the biomedical justification grows for earlier initiation of treatment; (2) CD4 evaluations are conducted at multiple services providing HIV care; thus it remains unclear to which service the patient is presenting late; and (3) the limited availability of CD4 evaluation restricts its use in determining the prevalence of LP in many settings.

CONCLUSIONS

The consensus definition is useful because it describes the level of disease progression and allows for consistent evaluation of the prevalence and determinants of LP. Suggestions are provided for improving the application of the consensus definition in future research.

Association between use of specific drugs and antiretroviral adherence: findings from MACH 14

To determine the association between individual substances of abuse and antiretroviral adherence, analyses require a large sample assessed using electronic data monitoring (EDM). In this analysis, EDM data from 1,636 participants in 12 US adherence-focused studies were analyzed to determine the associations between recent use of various substances and adherence during the preceding 4 weeks. In bivariate analyses comparing adherence among patients who had used a specific substance to those who had not, adherence was significantly lower among those who had recently used cocaine, other stimulants or heroin but not among those who had used cannabis or alcohol. In multivariate analyses controlling for sociodemographics, amount of alcohol use and recent use of any alcohol, cocaine, other stimulants and heroin each was significantly negatively associated with adherence. The significant associations of cocaine, other stimulants, heroin, and alcohol use with adherence suggest that these are important substances to target with adherence-focused interventions.

Tuberculosis in HIV programmes in lower-income countries: practices and risk factors

BACKGROUND

Tuberculosis (TB) is a common diagnosis in human immunodeficiency virus (HIV) infected patients on antiretroviral treatment (ART).

OBJECTIVE

To describe TB-related practices in ART programmes in lower-income countries and identify risk factors for TB in the first year of ART.

METHODS

Programme characteristics were assessed using standardised electronic questionnaire. Patient data from 2003 to 2008 were analysed and incidence rate ratios (IRRs) calculated using Poisson regression models.

RESULTS

Fifteen ART programmes in 12 countries in Africa, South America and Asia were included. Chest X-ray, sputum microscopy and culture were available free of charge in respectively 13 (86.7%), 14 (93.3%) and eight (53.3%) programmes. Eight sites (53.3%) used directly observed treatment and five (33.3%) routinely administered isoniazid preventive treatment (IPT). A total of 19 413 patients aged ≥ 16 years contributed 13,227 person-years of follow-up; 1081 new TB events were diagnosed. Risk factors included CD4 cell count (>350 cells/μl vs. <25 cells/μl, adjusted IRR 0.46, 95%CI 0.33-0.64, P < 0.0001), sex (women vs. men, adjusted IRR 0.77, 95%CI 0.68-0.88, P = 0.0001) and use of IPT (IRR 0.24, 95%CI 0.19-0.31, P < 0.0001).

CONCLUSIONS

Diagnostic capacity and practices vary widely across ART programmes. IPT prevented TB, but was used in few programmes. More efforts are needed to reduce the burden of TB in HIV co-infected patients in lower income countries.

The relationship between HAART use and sexual activity among HIV-positive women of reproductive age in Brazil, South Africa, and Uganda

The purpose of this study was to determine whether current HAART use is associated with recent sexual intercourse among HIV-infected women (18-49 years) from Brazil, South Africa and Uganda. We conducted an analysis of survey data from a cross-sectional study, which enrolled 179 HIV-infected women receiving regular care from the Mbarara Hospital HIV Clinic in Uganda (n=85); the Perinatal HIV Research Unit in Soweto, South Africa (n=50); and the IPEC-Fiocruz cohort in Rio de Janeiro, Brazil (n=44). The primary outcome was sexual intercourse in the previous month. Secondary outcomes were protected sex and contraceptive use. We found that overall, 46% reported recent sexual intercourse. After adjusting for covariates, recent sexual intercourse was not associated with HAART use (AOR: 0.76; 95%CI: 0.34-1.72); however, it was significantly associated with being currently married, wanting to have more children and having higher HAART optimism. Among women reporting recent sexual intercourse (n=83), HAART users were significantly more likely to practice protected sex (crude OR: 3.64; 95%CI: 1.41-9.38) and non-significantly more likely to use contraceptive methods (crude OR: 2.15; 95%CI: 0.77-5.99). In summary, self-reported recent sexual intercourse is not more likely among women on HAART. Moreover, sexually active HAART users may be more likely to practice protected sex and use contraceptives.

Community-based rapid HIV testing in homeless and marginally housed adults in San Francisco

BACKGROUND

Standard two-step HIV testing is limited by poor return-for-results rates and misses high-risk individuals who do not access conventional testing facilities.

METHODS

We describe a community-based rapid HIV testing programme in which homeless and marginally housed adults recruited from shelters, free meal programmes and single room occupancy hotels in San Francisco received OraQuick Rapid HIV-1 Antibody testing (OraSure Technologies, Bethlehem, PA, USA).

RESULTS

Over 8 months, 1614 adults were invited to participate and 1213 (75.2%) underwent testing. HIV seroprevalence was 15.4% (187 of 1213 individuals) overall and 3.5% (37 of 1063) amongst high-risk individuals reporting no previous testing, a prior negative test, or previous testing without result disclosure. All 1213 participants received their results. Of 30 newly diagnosed persons who received confirmatory results, 26 (86.7%) reported at least one contact with a primary healthcare provider in the 6 months following diagnosis.

CONCLUSIONS

We conclude that community-based rapid testing is feasible, acceptable and effective based on the numbers of high-risk persons tested over a short period, the participation rate, the prevalence of new infection, the rate of result disclosure, and the proportion linked to care.

Peripheral CD4 loss of regulatory T cells is associated with persistent viraemia in chronic HIV infection

Chronic HIV infection is associated with T cell abnormalities and altered effector function. Regulatory T cells (Treg) are CD4+ T cells that play a critical role in regulating the immune system. The impact of regulatory T cells on HIV infection and disease progression may be highly significant. We hypothesize that chronic antigenic stimulation from a persistent, high viraemic state may promote a population of Treg that contributes to HIV-associated immune dysfunction. We evaluated the pattern of Treg in chronically infected, HIV-positive individuals over a course of 6 months. Treg are depleted at a distinct rate from that of absolute CD4 cells and loss of Treg is slower in the presence of viral suppression. In vitro depletion of CD25+ CD4+ cells resulted in increased Gag-specific CD4 and CD8 responses. A significant correlation between ex vivo measurement of Treg and Gag-specific CD4 T cell responses was observed (r=-0 x 41, P=0 x 018) with a trend observed with Gag-specific CD8 T cell responses (P=0 x 07). The impact of HIV infection on the Treg population directly complicates the measured effect of Treg on the immune dysfunction although our data support the important role of Treg on modulating the effector T cell response in chronic infection.

Effects of HIV-related stigma among an early sample of patients receiving antiretroviral therapy in Botswana

Botswana, with its estimated HIV prevalence of 37%, instituted a policy of universal access to antiretroviral therapy (ART) in 2002. Initial enrolment lagged behind expectations, with a shortfall in voluntary testing that observers have attributed to HIV-related stigma - although there are no published data on stigma among HIV-positive individuals in Botswana. We interviewed 112 patients receiving ART in 2000, finding evidence of pervasive stigma in patterns of disclosure, social sequelae, and delays in HIV testing. Ninety-four percent of patients reported keeping their HIV status secret from their community, while 69% withheld this information even from their family. Twenty-seven percent of patients said that they feared loss of employment as a result of their HIV status. Forty percent of patients reported that they delayed getting tested for HIV; of these, 51% cited fear of a positive test result as the primary reason for delay in seeking treatment, which was often due to HIV-related stigma. These findings suggest that success of large-scale national ART programmes will require initiatives targeting stigma and its social, economic and political correlates.

Explaining variability in the relationship between antiretroviral adherence and HIV mutation accumulation

OBJECTIVES

Determining the relationship between antiretroviral adherence and resistance accumulation is important for the design and evaluation of adherence interventions. Our objective was to explain heterogeneity observed in this relationship.

METHODS

We first conducted a systematic review to locate published reports describing the relationship between adherence and resistance. We then used a validated computer simulation to simulate the patient populations in these reports, exploring the impact of changes in individual patient characteristics (age, CD4, viral load, prior antiretroviral experience) on the shape of the adherence-resistance (A-R) curve.

RESULTS

The search identified 493 titles, of which 3 contained relevant primary data and 2 had sufficient follow-up for inclusion (HOMER and REACH cohorts). When simulating HOMER, the A-R curve had a high peak with a greatly increased hazard ratio (HR) of accumulating mutations at partial compared to complete adherence (simulation, HR 2.9; HOMER, HR 2.7). When simulating REACH, the A-R curve had a shallow peak with a slightly increased hazard of accumulating mutations at partial adherence (simulation, HR 1.2; REACH, HR 1.4). This heterogeneity was primarily attributable to differences in antiretroviral experience between the cohorts.

CONCLUSIONS

Our computer simulation was able to explain much of the heterogeneity in observed A-R curves.

The price of adherence: qualitative findings from HIV positive individuals purchasing fixed-dose combination generic HIV antiretroviral therapy in Kampala, Uganda

Contrary to early expectations, recent studies have shown near-perfect adherence to HIV antiretrovirals in sub-Saharan Africa We conducted qualitative interviews with patients purchasing low-cost, generic antiretroviral therapy to better understand the social dynamics underlying these findings. We found that concerns for family well-being motivate adherence, yet, the financial sacrifices necessary to secure therapy may paradoxically undermine family welfare. We suggest that missed doses may be more due to a failure to access medication rather than a failure to adhere to medications, and that structural rather than behavioral interventions may be most useful to insure optimal treatment response.

Case management is associated with improved antiretroviral adherence and CD4+ cell counts in homeless and marginally housed individuals with HIV infection

BACKGROUND

Case management (CM) coordinates care for persons with complex health care needs. It is not known whether CM is effective at improving biological outcomes among homeless and marginally housed persons with human immunodeficiency virus (HIV) infection. Our goal was to determine whether CM is associated with reduced acute medical care use and improved biological outcomes in homeless and marginally housed persons with HIV infection.

METHODS

We conducted a prospective observational cohort study in a probability-based community sample of HIV-infected homeless and marginally housed adults in San Francisco, California. The primary independent variable was CM, defined as none or rare (any CM in <or=25% of quarters in the study), moderate (>25% but <or=75%), or consistent (>75%). The dependent variables were 3 self-reported health service use measures (receipt of primary care, emergency department visits and hospitalizations, and antiretroviral therapy adherence) and 2 biological measures (increase in CD4(+) cell count of >or=50% and geometric mean HIV load of <or=400 copies/mL).

RESULTS

In multivariate models, CM was not associated with increased primary care, emergency department use, or hospitalization. Moderate CM, compared with no or rare CM, was associated with an adjusted beta coefficient of 0.13 (95% confidence interval [CI], 0.02-0.25) for improved antiretroviral adherence. Consistent CM (adjusted odds ratio [AOR], 10.7; 95% CI, 2.3-49.6) and moderate CM (AOR, 6.5; 95% CI, 1.3-33.0) were both associated with >or=50% improvements in CD4(+) cell count. CM was not associated with geometric HIV load <400 copies/mL when antiretroviral therapy adherence was included in the model. Study limitations include a lack of randomization.

CONCLUSION

CM may be a successful method to improve adherence to antiretroviral therapy and biological outcomes among HIV-infected homeless and marginally housed adults.

Modeling the Impact of Modified Directly Observed Antiretroviral Therapy on HIV Suppression and Resistance, Disease Progression, and Death

A simulation model that used Markov assumptions with Monte Carlo uncertainty analysis was evaluated 1500 times at 10,000 iterations. Modified directly observed therapy (MDOT) for human immunodeficiency virus was assumed to improve adherence to therapy to 90% of prescribed doses. The impact of MDOT interventions on modeled biological and clinical outcomes was compared for populations with mean rates of adherence (i.e., the mean percentage of prescribed doses taken by each member of the population who had not discontinued therapy) of 40%, 50%, 60%, and 70%. MDOT reduced the risk of virological failure, development of opportunistic infections, and death, yet increased the risk of drug resistance, for each adherence distribution among persons with detectable plasma virus loads. Over 1500 trials, for a population with 50% adherence to therapy and a 12-month period, MDOT increased the median rate of virological suppression from 13.2% to 37.0% of patients, decreased the rate of opportunistic infection from 5.7% to 4.3% of patients, and decreased the death rate from 2.9% to 2.2% of patients. In the same population, however, MDOT increased the rate of new drug resistance mutations from 1.00 to 1.41 per person during the 12-month period. The impact of MDOT was smaller in populations with higher levels of adherence. MDOT interventions will likely improve clinical outcomes in populations with low levels of adherence but may not be effective at preventing drug resistance in treatment-experienced populations. MDOT may be more effective in preventing drug resistance with potent regimens in treatment-naive patients.

Reliability and validity of the SF-36 in HIV-infected homeless and marginally housed individuals

OBJECTIVE

To assess the reliability and validity of the Short-Form 36 (SF-36) health survey as a health status indicator among HIV-infected homeless and marginally housed (HMH) individuals.

METHODS

Between July 1996 and May 2000, a sample of HMH individuals completed interviews that included the SF-36. Responses to the SF-36 were analyzed for missing data, range, internal consistency, and construct validity.

RESULTS

Among 330 individuals interviewed, 83% were male, 43% were African-American, and the median age was 39 years. All internal consistency reliability coefficients exceeded 0.70, all item-scale correlations exceeded 0.40, all items were more strongly correlated with their hypothesized scale than any other scale, and all reliability coefficients exceeded inter-scale correlations for the same scale. Three of four physical health scales were significantly associated with CD4 cell count and HIV viral load. All scales were significantly associated with depression.

DISCUSSION

We found that scales were internally consistent, items correlated to an acceptable degree with their hypothesized scales, items were distinct from other scales, physical scales were associated with CD4 cell count and viral load, and all scales were associated with depression. These analyses provide evidence for the reliability and validity of the SF-36 as a measure of health status in HIV-positive HMH individuals.

A computer-based assessment detects regimen misunderstandings and nonadherence for patients on HIV antiretroviral therapy

Accurately assessing nonadherence is a necessary first step toward improving adherence to highly active antiretroviral therapy (HAART). Patient self report is the most practical method for assessing adherence in clinical settings, but may produce unreliable and invalid results unless optimally performed. A computer-assisted, self-administered interview (CASI) may improve the disclosure of medication nonadherence by providing a neutral and seemingly private interview. One hundred and ten patients completed a computer program which assessed their understanding of and adherence to HIV medications and produced a report for their providers. Eleven providers of these patients completed a questionnaire describing their patients' medication regimens and estimating adherence. Patients completed a written exit survey and providers completed an exit interview to assess the acceptability of our CASI-based assessment. More than half of patients (54%) made at least one error in reporting their medication regimen. Providers tended to overestimate their patients' adherence and correctly classified only 24% of nonadherent patients at the 80% adherence level. Computerized HIV medication adherence assessment is feasible and acceptable to patients and providers. Clinical tools that can accurately and efficiently detect important medication errors and nonadherence, and alert providers to these problems, will help ensure the health of HIV-seropositive patients.

HIV incidence among repeat HIV testers at a county hospital, San Francisco, California, USA

OBJECTIVES

To estimate HIV incidence, characterize correlates of HIV seroconversion, and monitor temporal trends in HIV transmission among patients repeatedly tested for HIV by a county hospital in San Francisco.

DESIGN

Retrospective longitudinal study.

METHODS

HIV incidence was retrospectively calculated among persons voluntarily tested for HIV antibody more than once at San Francisco's county hospital or one of its affiliated satellite community clinics between 1993 and 1999. Linkage of HIV test results in computerized databases identified "seroconverters" as individuals who had a negative antibody test followed by a positive test. The interval between tests was used as the person-time at risk. Cox proportional hazards analysis identified correlates of HIV seroconversion.

RESULTS

A total of 84 HIV seroconversions were identified among 2893 eligible patients repeatedly tested for HIV antibody over a cumulative 5860 person-years (PYs) (incidence of 1.4 per 100 PYs, 95% confidence interval [CI]: 1.2-1.7). The majority of seroconversions (71 [84.5%]) were among injection drug users (IDUs) (incidence of 2.0 per 100 PYs, CI: 1.6-2.4). HIV incidence was highest among men who have sex with men (MSM) who were also IDUs (incidence of 3.8 per 100 PYs, CI: 2.7-5.1) and lowest among non-IDUs, heterosexual men, and non-IDU women (incidence of 0.3 per 100 PYs, CI: 0.1-0.6). In multivariate analysis, correlates of HIV seroconversion were age 25 to 29 years (hazard ratio [HR] = 3.9, CI: 2.4-6.3), MSM (HR = 2.9, CI: 1.9-4.4), and IDU (HR = 3.2, CI: 1.8-5.8). Overall, no temporal trend in annual HIV incidence was noted during the study period; however, HIV incidence among MSM IDUs increased from 2.9 per 100 PYs in 1996 to 4.7 per 100 PYs in 1998.

CONCLUSIONS

The rate of seroconversion in this hospital and affiliated clinic population is unexpectedly high. Moreover, HIV transmission among IDU patients has not decreased over the last several years. The San Francisco county hospital provides a high-risk sentinel population to monitor emerging trends in HIV transmission, especially among IDUs, and presents multiple opportunities for prevention interventions, because these patients are being seen repeatedly by clinicians.

Provider assessment of adherence to HIV antiretroviral therapy

BACKGROUND

Adherence assessment is an essential component of monitoring HIV antiretroviral therapy. Prior studies suggest that medical providers frequently estimate individual patient adherence inaccurately.

OBJECTIVE

We compared provider estimates of nonadherence to antiretroviral therapy with unannounced pill counts and structured patient interviews to determine the accuracy of adherence information obtained by providers and patients.

DESIGN, SETTING, AND PARTICIPANTS

Comparison of three adherence measures in homeless or marginally housed persons receiving HIV antiretroviral therapy (n = 45) and their providers (n = 35).

MEASUREMENTS

Provider estimate of percentage of pills taken; three successive patient structured reports of number of doses missed in the last 3 days; and three successive unannounced pill counts.

RESULTS

13% (95% confidence interval [CI], 4%-22%) of patients were not following their regimen as directed. Provider-adherence estimate explained only 26% (95% CI, 6%-47%) of the variation in pill count adherence, whereas patient report explained 72% (95% CI, 52%-96%). The sensitivity and specificity of provider estimates of nonadherence, defined as <80% of pills taken by pill count, were 40% and 85%, respectively. The sensitivity and specificity of patient interview were 72% and 95%, respectively.

CONCLUSIONS

Provider estimate of adherence was inaccurate whereas structured patient report was more closely related to pill count. Structured assessment over several short intervals may improve accuracy of adherence assessment in clinical practice.

Risk of infection from needle reuse at a phlebotomy center

OBJECTIVES

This study determined infection risk for HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) from needle reuse at a phlebotomy center that possibly exposed 3810 patients to infection.

METHODS

We used a model for the risk of infection per blood draw, supplemented by subsequent testing results from 1699 patients.

RESULTS

The highest risk of transmission was for HBV infection: 1.1 x 10(-6) in the best case and 1.2 x 10(-3) in the (unlikely) worst case. Subsequent testing yielded prevalence rates of 0.12%, 0.41%, and 0.88% for HIV, HBV, and HCV, respectively, lower than National Health and Nutrition Examination Survey III prevalence estimates.

CONCLUSIONS

The infection risk was very low; few, if any, transmissions are likely to have occurred.

A heterogeneous outbreak of Enterobacter cloacae and Serratia marcescens infections in a surgical intensive care unit

OBJECTIVE

To investigate an outbreak of invasive disease due to Enterobacter cloacae and Serratia marcescens in a surgical intensive care unit (ICU).

DESIGN

Pulsed-field gel electrophoresis (PFGE) analysis of restriction fragments was used to characterize the outbreak isolate genotypes. A retrospective cohort study of surgical ICU patients was conducted to identify risk factors associated with invasive disease. Unit staffing data were analyzed to compare staffing levels during the outbreak to those prior to and following the outbreak.

SETTING

An urban hospital in San Francisco, California.

PATIENTS

During the outbreak period, December 1997 through January 1998, there were 52 patients with a minimum ICU stay of > or = 72 hours. Of these, 10 patients fit our case definition of recovery of E. cloacae or S. marcescens from a sterile site.

RESULTS

PFGE analysis revealed a highly heterogeneous population of isolates. Bivariate analysis of patient-related risk factors revealed duration of central lines, respiratory colonization, being a burn patient, and the use of gentamicin or nafcillin to be significantly associated with invasive disease. Both respiratory colonization and duration of central lines remained statistically significant in a multivariate analysis. Staffing data suggested a temporal correlation between understaffing and the outbreak period.

CONCLUSIONS

Molecular epidemiological techniques provided a rapid means of ruling out a point source or significant cross-contamination as modes of transmission. In this setting, patient-related risk factors, such as respiratory colonization and duration of central lines, may provide a focus for heightened surveillance, infection control measures, and empirical therapy during outbreaks caused by common nosocomial pathogens. In addition, understaffing of nurses may have played a role in this outbreak, highlighting the importance of monitoring staffing levels.

Adherence to protease inhibitors, HIV-1 viral load, and development of drug resistance in an indigent population

OBJECTIVE

To examine the relationship between adherence, viral suppression and antiretroviral resistance in HIV-infected homeless and marginally housed people on protease inhibitor (PI) therapy.

DESIGN AND SETTING

A cross-sectional analysis of subjects in an observational prospective cohort systematically sampled from free meal lines, homeless shelters and low-income, single-room occupancy (SRO) hotels.

PARTICIPANTS

Thirty-four HIV-infected people with a median of 12 months of PI therapy.

MAIN OUTCOMES

Adherence measured by periodic unannounced pill counts, electronic medication monitoring, and self-report; HIV RNA viral load; and HIV-1 genotypic changes associated with drug resistance.

RESULTS

Median adherence was 89, 73, and 67% by self-report, pill count, and electronic medication monitor, respectively. Thirty-eight per cent of the population had over 90% adherence by pill count. Depending on the measure, adherence explained 36-65% of the variation in concurrent HIV RNA levels. The three adherence measures were closely related. Of 20 genotyped patients who received a new reverse transcriptase inhibitor (RTI) when starting a PI, three had primary protease gene substitutions. Of 12 genotyped patients who received a PI without a new RTI, six had primary protease gene substitutions (P < 0.03).

CONCLUSION

A substantial proportion of homeless and marginally housed individuals had good adherence to PI therapy. A strong relationship was found between independent methods of measuring adherence and concurrent viral suppression. PI resistance was more closely related to the failure to change RTI when starting a PI than to the level of adherence.

Reduction in tuberculin skin-test conversions among medical house staff associated with improved tuberculosis infection control practices

OBJECTIVE

To assess the efficacy of an infection control program as measured by tuberculin skin-test (TST) conversion rates in medical house staff.

DESIGN

Observational study.

SETTING

University-based hospital in New York City serving a large indigent population.

PARTICIPANTS

Medical house staff.

INTERVENTIONS

TST conversions were measured every 6 months in medical house staff from June 1992 to June 1994. Compliance with the isolation policy was measured by identifying room locations 24 hours after admission of patients who had Mycobacterium tuberculosis recovered from respiratory specimens.

RESULTS

The TST conversion rate decreased from 5.8 to 0, 2.3, and 0 per 100 person years of exposure in successive 6-month periods. The estimated annual TST conversion rate among interns fell from 7 per 100 person years in June 1992 to 0 per 100 person years in June 1993 and 0 per 100 person years in June 1994 (P < .029). The proportion of patients with pulmonary tuberculosis who were isolated in negative-pressure rooms increased from 38% to 75% over the study period (P < .01).

CONCLUSION

Development of a multifaceted infection control program can decrease the risk of nosocomial tuberculosis infection in medical house staff.

In vivo gonadotropin-releasing hormone release and serum luteinizing hormone measurements in ovariectomized, estrogen-treated rhesus macaques

The push-pull perfusion technique was used to measure GnRH release in unanesthetized female rhesus macaques (Macaca mulatta) and to examine the dynamic relationship between GnRH release and LH levels during the estrogen-induced LH surge. Each ovariectomized macaque was anesthetized and stereotaxically fitted with a push-pull cannula directed into the median eminence (ME). After at least 1 week of recovery, each animal received an estradiol benzoate (E2B) injection (42 micrograms/kg BW) or an oil (OIL) injection and underwent push-pull perfusion of the ME and blood sampling for at least 5 h between 28 and 56 h postinjection. Continuous 10-min push-pull perfusates were collected and prepared for GnRH RIA. Peripheral venous blood samples were obtained either hourly or every 10 min, and serum LH levels were determined by Leydig cell bioassay. GnRH release was detectable and pulsatile in areas in or adjacent to the ME or arcuate nucleus. In eight OIL monkeys, GnRH pulses were regular (approximately one pulse every 60 min) and of low amplitude (14.7 +/- 12.0 pg), with a mean GnRH release rate of 4.0 +/- 1.7 pg/10 min. In five E2B-treated monkeys, GnRH release during the rising phase of the LH surge occurred as an apparent burst of high amplitude GnRH pulses. The mean GnRH release rate (37.5 +/- 17.9 pg/10 min) and mean GnRH pulse amplitude (170.0 +/- 90.0 pg) during the 5 h before the peak LH level in E2B-treated monkeys were greater than OIL values (P less than 0.025, mean release; P less than 0.05, mean amplitude). Within individual E2B-treated monkeys, hourly mean GnRH release rates were significantly correlated with LH levels during the ascending limb of the LH surge (r = 0.75 +/- 0.11; P less than 0.025). We have concluded that an increase in GnRH neurosecretion occurs in E2B-treated monkeys and that it is associated with generation of the LH surge. On the basis of our observations, we hypothesize that the primate hypothalamus, through changes in GnRH secretion, actively participates in the E2B-induced LH surge.