Unfolded Von Willebrand Factor Binds Protein S and Reduces Anticoagulant Activity

Protein S (PS), the critical plasma cofactor for the anticoagulants tissue factor (TF) pathway inhibitor (TFPI) and activated protein C (APC), circulates in two functionally distinct pools: free (anticoagulant) or bound to complement component 4b-binding protein (C4BP) (anti-inflammatory). Acquired free PS deficiency is detected in several viral infections, but its cause is unclear. Here, we identified a shear-dependent interaction between PS and von Willebrand Factor (VWF) by mass spectrometry. Consistently, plasma PS and VWF comigrated in both native and agarose gel electrophoresis. The PS/VWF interaction was blocked by TFPI but not APC, suggesting an interaction with the C-terminal sex hormone binding globulin (SHBG) region of PS. Microfluidic systems, mimicking arterial laminar flow or disrupted turbulent flow, demonstrated that PS stably binds VWF as VWF unfolds under turbulent flow. PS/VWF complexes also localized to platelet thrombi under laminar arterial flow. In thrombin generation-based assays, shearing plasma decreased PS activity, an effect not seen in the absence of VWF. Finally, free PS deficiency in COVID-19 patients, measured using an antibody that binds near the C4BP binding site in SHBG, correlated with changes in VWF, but not C4BP, and with thrombin generation. Our data suggest that PS binds to a shear-exposed site on VWF, thus sequestering free PS and decreasing its anticoagulant activity, which would account for the increased thrombin generation potential. As many viral infections present with free PS deficiency, elevated circulating VWF, and increased vascular shear, we propose that the PS/VWF interaction reported here is a likely contributor to virus-associated thrombotic risk.

744. Infectious Diseases Providers Perspectives Around the Use of Outpatient Parenteral Antibiotic Therapy (OPAT) for Persons Who Inject Drugs (PWID), US, 2022

Background

Injection drug use-related infections are life threatening and may require prolonged courses of antibiotic therapy. There is no consensus on best practices for serious infections when patients are stable for discharge. Outpatient parenteral antimicrobial therapy (OPAT) has been shown to be feasible for people who inject drugs (PWID) especially when paired with medication for opioid use disorder. We set out to determine the current practice patterns and attitudes of infectious diseases (ID) clinicians in the United States regarding the use of OPAT for PWID.

Methods

We surveyed ID clinicians between January 2022 and March 2022. Topics focused on PWID including OPAT access, barriers to inclusion in OPAT, and factors clinicians considered for OPAT success. Responses from those who perceived PWID were eligible for OPAT (PWID-E) were compared to those who believed PWID were ineligible (PWID-I) using the Pearson chi-squared test.

Results

Of 239 clinician respondents, 80% were MD, 6% DO, 5% NP, 2% PA, and 7% Pharmacists. 187 (78.2%) work at an academic practice and 179 (75%) work in an urban setting. 182 (76%) respondents have access to inpatient addiction medicine services and 206 (86%) reported availability of outpatient addiction treatment, but only 86 (36%) described patient access to outpatient services as “good” or “excellent.”

Respondents were categorized as PWID-E (n=171, 72%) and PWID-I (n=68, 28%). Of the PWID-E group, only 48 (28%) have an institutional policy for determining eligibility. There was no significant difference in practice setting or access to addiction services between PWID-E and PWID-I. Access to inpatient and outpatient social work/case management was significantly higher for PWID-E. (Table 1).

Clinicians reporting PWID-I were more likely to cite risk of tampering with PICC (76.5% vs 62.6%, p = 0.04) and medical-legal risk (47.1% vs 19.3%, p < 0.001) as barriers to OPAT. (Table 2).

Conclusion

A high proportion of respondents to this national survey offer OPAT for PWID, but only a minority have an institutional policy for eligibility. Guidelines that outline a framework for discharge decision making, education regarding medical and legal risk, and development of best practices may help to standardize care across settings.

Disclosures

Ellen Eaton, MD, MPH, Gilead HIV Research Scholar: Grant/Research Support|Gilead HIV research scholar: Grant/Research Support Monica K. Sikka, MD, F2G: Site research investigator.

2065. Increasing the HIV screening rates in Rural Syringes Service Programs

Background

The Kentucky Income Reinvestment Program (KIRP) is a statewide reinvestment of income generated by the Ryan White HIV/AIDS Program (RWHAP) Kentucky AIDS Drug Assistance Program, which provides comprehensive early intervention services targeting those at the highest risk for HIV infection. The objective of this study was to compare the HIV screening rates in persons who inject drugs (PWID) at Syringe Service Programs (SSP) supported by KIRP versus SSPs not supported by KIRP in Kentucky

Methods

A cross-sectional study was conducted on 54 SSPs. We compared the HIV screening rates in the first quarter of 2020, 2021, and 2022. Fisher's exact test compared the HIV screening rates between the KIRP supported SSPs (KSSP) versus Non-KIRP supported SSPs (NKSSP). Study data were collected and managed using REDCap electronic data capture tools hosted at Kentucky Department for Public Health. The statistical analyses were performed with Stata 17 (College Station, TX: Stata Corp LLC).

Results

The analysis included data of 21,072 PWID who attended the SSPs utilizing the REDCap electronic data capture tool during the study timeframe. In the first quarter of 2022, a total of 1,607/4795 (33.5%) PWID were screened for HIV at KSSP vs 12/482 (2.5%) at NKSSP (p=&lt; 0.001). The difference in the screening rates has increased over the years since the KIRP began in 2019 (Figure 1).

Conclusion

The HIV screening rate in PWID has increased significantly in the SSPs supported by KIRP through RWHAP program income early intervention funds. This increase has occurred mainly in rural counties where people who inject drugs remain a significant population at risk for new HIV infections.

Disclosures

All Authors: No reported disclosures.

1246. Prevalence of Hepatitis C Antibodies (Ab) in people at risk for HIV infection in Kentucky

Background

The Kentucky Income Reinvestment Program (KIRP) provides comprehensive early intervention services targeting those at the highest risk for HIV infection. The objective of this study was to evaluate the prevalence of Hepatitis C Antibodies (HCV Ab) in people at risk for HIV infections in Kentucky.

Methods

A cross-sectional study was conducted using the KIRP Outreach database, including data from people at risk for HIV infections from January 2021 to March 2022. A screening tool was used to identify the people at risk. A Point-of-Care rapid test was used for the detection of HCV Ab. We compared the frequency of HCV Ab in People who inject drugs (PWID) versus people who denied the use of injected drugs. Study data were collected and managed using REDCap electronic data capture tools hosted at the University of Kentucky. Logistic Regression was performed, and the OR was reported. The statistical analyses were performed with Stata 17 (College Station, TX: Stata Corp LLC).

Results

The analysis included data of 8,225 people tested for Hepatitis C concomitant to screening for HIV; of them, 4,203 (51.1%) were female, and the median age was 41 years old (Range: 17 – 76). No previous test for HCV Ab detection was reported in 3,966 (48.2%).

A total of 1,180 (14.3%) tests were positive. HIV infection was detected in 14 (0.2%) people; of them 3 (21.5%) were in people with detectable HCV Ab. The prevalence of HCV Ab in PWID was 36.6%, and the prevalence in people who denied the use of injected drugs was 5.0% (p&lt; 0.001). Most people with detectable HCV Ab (68.0%) were younger than 45. After being adjusted by age, HCV Ab was strongly associated with PWID (OR: 9.3; 95% CI 7.9 – 11.0; p&lt; 0.001).

Conclusion

The prevalence of the Hepatitis C virus in Kentucky remains higher, mainly in PWID; it was not associated with age. HCV/HIV Coinfection was identified in more than 20% of the Clients. Efforts to continue screening both HIV and HCV infections in PWID are necessary.

Disclosures

All Authors: No reported disclosures.

Factors Associated With Systemic Immune Activation Indices in a Global Primary Cardiovascular Disease Prevention Cohort of People With Human Immunodeficiency Virus on Antiretroviral Therapy

BACKGROUND

Among antiretroviral therapy (ART)-treated people with human immunodeficiency virus (PWH), persistent systemic immune activation contributes to atherogenesis atherosclerotic, cardiovascular disease (CVD) events, and mortality. Factors associated with key immune activation indices have not previously been characterized among a global primary CVD prevention cohort of PWH.

METHODS

Leveraging baseline Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) data, we evaluated factors associated with soluble CD14 (sCD14) and oxidized low-density lipoprotein (oxLDL).

RESULTS

The primary analysis cohort included 4907 participants from 5 global-burden-of-disease regions (38% female, 48% Black, median age 50 years). In fully adjusted models for sCD14, female sex and White race (among those in high-income regions) were associated with higher sCD14 levels, while higher body mass index (BMI) and current use of nucleoside reverse transcriptase inhibitor + integrase strand transfer inhibitor ART were associated with lower sCD14 levels. In fully adjusted models for oxLDL, male sex, residence in high-income regions, White race (among those in high-income regions), and higher BMI were associated with higher oxLDL levels. In a subanalysis cohort of 1396 women with HIV, increased reproductive age was associated with higher sCD14 levels but not with higher oxLDL levels.

CONCLUSIONS

Factors associated with sCD14 and oxLDL, 2 key indices of immune-mediated CVD risk, differ. Future studies will elucidate ways in which medications (eg, statins) and behavioral modifications influence sCD14 and oxLDL and the extent to which dampening of these markers mediates CVD-protective effects.

CLINICAL TRIALS REGISTRATION

NCT0234429.

Long-term high-dose immunoglobulin successfully treats Long COVID patients with pulmonary, neurologic, and cardiologic symptoms

Introduction

Long COVID is the overarching name for a wide variety of disorders that may follow the diagnosis of acute SARS-COVID-19 infection and persist for weeks to many months. Nearly every organ system may be affected.

Methods

We report nine patients suffering with Long COVID for 101 to 547 days. All exhibited significant perturbations of their immune systems, but only one was known to be immunodeficient prior to the studies directed at evaluating them for possible treatment. Neurological and cardiac symptoms were most common. Based on this data and other evidence suggesting autoimmune reactivity, we planned to treat them for 3 months with long-term high-dose immunoglobulin therapy. If there was evidence of benefit at 3 months, the regimen was continued.

Results

The patients' ages ranged from 34 to 79 years-with five male and four female patients, respectively. All nine patients exhibited significant immune perturbations prior to treatment. One patient declined this treatment, and insurance support was not approved for two others. The other six have been treated, and all have had a significant to remarkable clinical benefit.

Conclusion

Long-term high-dose immunoglobulin therapy is an effective therapeutic option for treating patients with Long COVID.

Design and protocol of the Buprenorphine plus Outpatient Parenteral Antimicrobial Therapy (B-OPAT) study: a randomized clinical trial of integrated outpatient treatment of opioid use disorder and severe, injection-related infections

Introduction

A marked increase in hospitalizations for severe, injection-related infections (SIRI) has been associated with the opioid epidemic. Outpatient parenteral antibiotic therapy (OPAT) is typically not offered to persons with opioid use disorder (OUD) and SIRI, though increasing evidence suggests it may be feasible and safe. This study evaluates the efficacy and cost-effectiveness of an integrated care model combining Buprenorphine treatment of OUD with OPAT for SIRI (B-OPAT) compared with treatment as usual on key OUD, infectious disease, and health economic outcomes. B-OPAT expands and incorporates key elements of established clinical models, including inpatient initiation of buprenorphine for OUD, inpatient infectious disease consultation for SIRI, office-based treatment of OUD, and OPAT, and includes more frequent clinical outpatient visits than standard OPAT. A qualitative evaluation is included to contextualize effectiveness outcomes and identify barriers and facilitators to intervention adoption and implementation.

Methods

B-OPAT is a single-site, randomized, parallel-group, superiority trial recruiting 90 adult inpatients hospitalized with OUD and SIRI who require at least 2 weeks of intravenous (IV) antibiotic therapy. After screening, eligible participants are randomized 1:1 to either discharge once medically stable to an integrated outpatient treatment care model combining Buprenorphine and OPAT (B-OPAT) or to Treatment As Usual (TAU). The primary outcome measure is the proportion of urine samples negative for illicit opioids in the 12 weeks after discharge from the hospital. Key secondary OUD outcomes include self-reported number of days of illicit opioid abstinence and 12-week retention in buprenorphine treatment. The infection outcomes are completion of recommended IV antibiotic therapy, peripherally inserted central catheter (PICC) complications, and readmission related to primary SIRI.

Conclusions

The B-OPAT study will help address the important question of whether it is clinically effective and cost-effective to discharge persons with OUD and SIRI to an integrated outpatient care model combining OUD treatment with OPAT relative to TAU (Clinicaltrials.gov Identifier: NCT04677114).

Outpatient Parenteral Antimicrobial Therapy Plus Buprenorphine for Opioid Use Disorder and Severe Injection-related Infections

In a pilot randomized trial in persons with opioid use disorder hospitalized with injection-related infections, an innovative care model combining outpatient parenteral antimicrobial therapy with buprenorphine treatment had similar clinical and drug use outcomes to usual care (inpatient intravenous antibiotic completion) and shortened hospital length of stay by 23.5 days.

CLINICAL TRIALS REGISTRATION

NCT03048643.

Impact of the Affordable Care Act on Referral to Care for People Living with HIV in Appalachia

Introduction

The Affordable Care Act (ACA) enacted on March 23, 2010 significantly impacted access to healthcare for people living with HIV (PLWH). Expansion of care was accomplished in three areas: eliminating exclusions for pre-existing conditions, elimination of lifetime caps on healthcare expenditures, and expansion of Medicaid eligibility.

Purpose

This study evaluated the impact of state implementation of the ACA Medicaid expansion on referral to HIV care at a Ryan White federally funded clinic in Kentucky (University of Kentucky Bluegrass Care Clinic [UK BCC]).

Methods

Retrospective chart review of all newly enrolled patients at the UK BCC between March 2010 and June 2017. Data included patient demographics and referral source, and were divided into two groups to compare enrollments before and after Kentucky implemented the ACA Medicaid expansion. Data were collected from 2018-2019 and analyzed in 2020.

Results

Following Medicaid expansion there were statistically significant changes in the patterns of referral to federally funded HIV care. These included a significant decrease in the proportion of referrals from state and local health departments, and an increase in both proportion of referrals from outpatient clinics and transfers from different HIV care providers.

Implications

These results have implications for engaging more PLWH into HIV care, particularly in states where patients have increased access to screening and assessment of risk at primary care encounters through implementation of the ACA Medicaid expansion.

Integrated outpatient treatment of opioid use disorder and injection-related infections: A description of a new care model

Persons with opioid use disorder (OUD) hospitalized with severe, injection-related infections (SIRI) are frequently hospitalized for the duration of IV antibiotic treatment due to concerns regarding their eligibility for outpatient parenteral antimicrobial therapy (OPAT), which is the standard of care for prolonged IV antibiotic courses for patients without drug use. As part of a pilot study, a novel, integrated care model was developed where patients with OUD and SIRI receive addiction consultation and buprenorphine induction while hospitalized, followed by ongoing management in an outpatient clinic that combines office-based opioid treatment with buprenorphine pharmacotherapy and counseling services with OPAT. Through three illustrative case vignettes the outpatient model is described along with challenges, lessons learned and future directions.

Alcohol Use and Multimorbidity Among Individuals Living with HIV

Alcohol is prevalent among people living with HIV and can lead to multiple comorbid conditions (multimorbidity). The purpose of this study was to examine the relationship between alcohol use history and multimorbidity among people living with HIV. A retrospective cohort study design was conducted at an urban, academic infectious disease clinic in Kentucky. Individuals seeking care between 2010 and 2014 were included. Modified Poisson regression was used to examine the relationship between alcohol use history (never, current, and former use) and multimorbidity (≥ 2 conditions). A total of 949 individuals were included in the study, with 5.1 and 17.6% reporting former and current alcohol use, respectively. Sixty-five percent had ≥ 1 condition and 82.6% of those had ≥ 2 conditions diagnosed. The risk of multimorbidity was 1.70 (95% CI 1.35-2.14) times higher for a current user compared to a never user. Reductions in alcohol use may lead to lower rates of multimorbidity.

Persistence of Macrocytosis after Discontinuation of Zidovudine in HIV-Infected Patients

The duration of macrocytosis after stopping zidovudine (ZDV) is unknown. Among 104 HIV-infected patients treated with ZDV for more than 1 year, 84 patients had macrocytosis at ZDV discontinuation. The median mean corpuscular volume (MCV) was 114.6 fL (range 100-128 fL). Patients were divided into 2 groups: those who did (resolved macrocytosis, n = 36) and did not (persistent macrocytosis, n = 48) normalize MCV at 3 to 6 months after ZDV discontinuation. Alcohol use ( P = .02), smoking ( P = .03), and lower (but within normal range) folic acid levels ( P = .05) were related to the persistence of macrocytosis. A persistence of macrocytosis was observed in 57% at 3 to 6 months, 38% at 1 year and 37% at 2 years after ZDV therapy had stopped. Duration of ZDV therapy did not have an effect on the persistence of macrocytosis ( P = .73). The median time for the MCV to normalize after stopping ZDV was 12.5 months.

A Qualitative Approach to Increasing HIV Prevention in Primary Care Settings for Older Adults: Perspectives From Primary Care Providers

The purpose of this research was to explore primary care providers' willingness and ability to increase HIV prevention efforts among older adults and to gain recommendations for improving HIV prevention in primary care settings. Data were collected through 24 semistructured interviews with primary care providers. The results of the study reveal that the majority of providers find it necessary to increase HIV prevention efforts in primary care settings and are willing to do so; however, they cannot do so without assistance. Providers suggested strategies to increase HIV prevention in primary care, for instance, expanding the use of electronic reminders to include HIV prevention and increasing collaboration among providers of different specialties. As a result of the interviews, additional recommendations for increasing HIV prevention have been identified. These findings will aid in improving the quality of care provided to individuals older than 50 in primary care settings.

Estimated cost per HIV infection diagnosed through routine HIV testing offered in acute general medical admission units and general practice settings in England

OBJECTIVES

Following national guidelines to expand HIV testing in high-prevalence areas in England, a number of pilot studies were conducted in acute general medical admission units (ACUs) and general practices (GPs) to assess the feasibility and acceptability of testing in these settings. The aim of this study was to estimate the cost per HIV infection diagnosed through routine HIV testing in these settings.

METHODS

Resource use data from four 2009/2010 Department of Health pilot studies (two ACUs; two GPs) were analysed. Data from the pilots were validated and supplemented with information from other sources. We constructed possible scenarios to estimate the cost per test carried out through expanded HIV testing in ACUs and GPs, and the cost per diagnosis.

RESULTS

In the pilots, cost per test ranged from £8.55 to £13.50, and offer time and patient uptake were 2 minutes and 90% in ACUs, and 5 minutes and 60% in GPs, respectively. In scenario analyses we fixed offer time, diagnostic test cost and uptake rate at 2 minutes, £6 and 80% for ACUs, and 5 minutes, £9.60 and 40% for GPs, respectively. The cost per new HIV diagnosis at a positivity of 2/1000 tests conducted was £3230 in ACUs and £7930 in GPs for tests performed by a Band 3 staff member, and £5940 in ACUs and £18 800 in GPs for tests performed by either hospital consultants or GPs.

CONCLUSIONS

Expanded HIV testing may be more cost-efficient in ACUs than in GPs as a consequence of a shorter offer time, higher patient uptake, higher HIV positivity and lower diagnostic test costs. As cost per new HIV diagnosis reduces at higher HIV positivity, expanded HIV testing should be promoted in high HIV prevalence areas.

Fulminant Invasive Pulmonary Aspergillosis After a Near-Drowning Accident in an Immunocompetent Patient

OBJECTIVE

To report on invasive aspergillosis infection in an immunocompetent adult after a near-drowning event, which allowed this pathogen to easily gain access to the human respiratory system and result in rapid, severe infection.

CASE SUMMARY

A 51-year-old female developed severe pneumonia after a near-drowning accident. Two days after admission, a bronchial alveolar lavage (BAL) was performed and was positive for Aspergillus fumigatus. After a 30-day hospital course, multiple antifungals, and various routes of administration, the patient expired.

DISCUSSION:

Pneumonia is particularly common because of the aspiration of contaminated water. Whereas pneumococci, staphylococci, and Gram-negative bacteria are all common pathogens for this type of infection, fungi such as Aspergillus spp can also be involved and may be life threatening. Typically, these cases are reported in individuals with an immunodeficiency such as from receipt of myelosuppressive chemotherapy, bone marrow transplants, or lung transplants. Despite initiation of an appropriate empirical antifungal regimen, the rapid recovery of A fumigatus from pulmonary alveolar lavage and BAL samples as well as extremely elevated levels of galactomannan and (1→3)-β-D glucan may have indicated an invasive fungal infection (IFI).

CONCLUSION:

IFIs are uncommon in immunocompetent adults, but in the event of a near-drowning accident, environmental fungi can gain access to the human respiratory system and result in rapid, severe infection. Based on this case and the others described, it appears that near-drowning patients need an early initial evaluation for IFI.

Role of CD4 count in immunity development after hepatitis A and B vaccination among HIV-infected patients: Kentucky, 2002-2007

PURPOSE

To determine whether lower prevaccination CD4 counts decrease odds of immune development against hepatitis A virus/hepatitis B virus (HAV/HBV) among patients who receive the vaccine and examine the relationship between vaccine response and sex, race/ethnicity, health insurance status, tobacco use, substance abuse, or comorbidities.

METHODS

This study was performed among patients who received the standard dose for HAV and/or HBV vaccine.

RESULTS

Among 76 HIV-infected patients, immunity development to HAV or HBV increased as CD4 counts increased. In addition, males had greater vaccine response than females. Whites were observed to have higher rates of immunity than other races/ethnicities. Patients with private insurance had greater vaccine response than those with Medicaid, Medicare, or no insurance. Patients not experiencing hypertension and hyperlipidemia developed immunity more often than patients with these comorbidities. Substance abuse and tobacco use were also associated with lower vaccine response.

CONCLUSIONS

Higher CD4 counts improved likelihood of patients developing an antibody response after vaccination.

Trimethoprim-sulfamethoxazole exposure alters ex vivo function of B lymphocytes isolated from human immunodeficiency virus-infected patients receiving Zidovudine

STUDY OBJECTIVE

To determine if exposure to trimethoprim-sulfamethoxazole (TMP-SMX) causes a defect in peripheral B-cell function among patients with the human immunodeficiency virus (HIV) who are receiving zidovudine antiretroviral therapy.

DESIGN

Prospective, single-center, single-group, case-crossover design with a 4-week exposure period.

SETTING

University-affiliated infectious diseases outpatient clinic.

PATIENTS

Fourteen HIV-infected adult men receiving zidovudine, who had CD4(+) cell counts above 350 cells/mm(3) and undetectable viral loads.

INTERVENTION

Patients were administered a 28-day course of TMP 160 mg-SMX 800 mg/day (one double-strength tablet/day). Peripheral blood mononuclear cells (PBMCs) were obtained and isolated before and after exposure to TMP-SMX. Cells were cultured ex vivo with three mitogens of differing immunologic properties: pokeweed mitogen ([PWM] T-cell-dependent B-cell mitogen), Staphylococcus aureus Cowan ([SAC] T-cell-independent B-cell mitogen), and phytohemagglutinin A ([PHA] T-cell mitogen). Functionality of the B and T lymphocytes was then assessed.

MEASUREMENTS AND MAIN RESULTS

Proliferative capacity, cytokine secretion, and antibody production were measured and compared before and after TMP-SMX exposure. Reduced proliferative capacities of both PBMC and B cells stimulated with mitogens were observed at the 3-day culture time point in response to PWM, PHA, and SAC (p=0.029, 0.028, and 0.026, respectively). Proliferative capacity at day 7 of culture was not significantly different for any condition examined. Cytokine production was not altered by combination drug exposure after 10 days of culture when cells were stimulated with either PWM or PHA. Although antibody responses to PWM and PHA were similar, total immunoglobulin G concentration was lower in cells stimulated with SAC in samples obtained after TMP-SMX regimen completion compared with those obtained before exposure (p=0.005).

CONCLUSION

Although these data were affected by limitations in power and study design, they suggest that peripheral B-lymphocyte function is altered as a result of TMP-SMX exposure in HIV-infected patients concurrently receiving zidovudine. Further study of this effect is warranted.

Blunted Humoral Response to Influenza Vaccination in Patients Exposed to Zidovudine plus Trimethoprim-Sulfamethoxazole

STUDY OBJECTIVES

To determine as proof of principle the effect of combination exposure to zidovudine plus trimethoprim-sulfamethoxazole (TMP-SMX) on humoral immune responses to influenza vaccination in patients with human immunodeficiency virus (HIV).

DESIGN

Prospective, open-label trial.

SETTING

University-affiliated infectious diseases outpatient clinic.

PATIENTS

Twenty-three HIV-infected adults receiving antiretroviral therapy, with CD4+ cell counts greater than 350 cells/mm3 and undetectable viral loads.

INTERVENTION

Patients were assigned to one of four treatment groups: zidovudine (6 patients), TMP-SMX (7), zidovudine plus TMP-SMX (5), or neither drug (5); TMP-SMX was given as a 28-day course. Patients were subsequently immunized with the yearly influenza vaccine, and humoral responses were compared among groups 20-24 days after vaccination.

MEASUREMENTS AND MAIN RESULTS

Antibody responses to influenza A and B were measured, and total and activated T and B cell percentages in the peripheral blood were determined. Mean influenza B-specific serum immunoglobulin (Ig)G titers were significantly lower in patients receiving TMP-SMX alone (0.98 +/- 0.60 reference value, p=0.010) or the combination of zidovudine plus TMP-SMX (0.73 +/- 0.29 reference value, p=0.003) compared with those receiving neither drug (1.95 +/- 0.38 reference value). This corresponded to a significantly lower percentage of patients in the combination group that achieved immunoprotective titers to influenza B compared with the group who received neither drug (control group; 20% vs 100%, p=0.048). In addition, the relationship between serum IgG titer and CD4+ cell count was statistically significantly different for patients exposed to zidovudine plus TMP-SMX versus control patients for both influenza A and B (F statistics 8.72 and 11.70, respectively, compared with critical F value 7.26 for p<0.025). Likewise, the relationship between influenza B serum IgG and CD4+ cell count was different among patients who received TMP-SMX versus those who did not receive TMP-SMX (F statistic 5.95 compared with critical F value 4.56 for p<0.025). No significant differences were observed among T and B cell percentages in the blood.

CONCLUSION

Combination exposure to zidovudine plus TMP-SMX causes a clinically significant suppression of humoral immune responses to influenza vaccination in HIV-infected patients.

Testing practices and knowledge of HIV among prenatal care providers in a low seroprevalence state

As the prevalence of heterosexually transmitted HIV increases among women of childbearing age in the United States, so too does the potential for vertical transmission from mother to child. Early maternal diagnosis and appropriate management are critical to minimizing the risk of perinatal infection. We designed a study to evaluate current prenatal care provider testing practices and knowledge of HIV as it relates to pregnancy in a low seroprevalence state. A written questionnaire was mailed to 642 prenatal care providers in Kentucky. Responses were compared to a similar survey conducted in 1998 and to current federal guidelines for HIV management. Nearly all respondents reported to offer HIV testing to all prenatal patients, demonstrating a marked improvement since 1998 (p < 0.001). However, clinicians did not report adequate follow-up when testing is refused and appear to have limited knowledge of the disease as it relates to pregnancy. Only 9.3% of respondents demonstrated proficiency on two knowledge assessment questions. Those with previous experience treating prenatal patients with HIV were more likely to respond correctly (odds ratio [OR] 3.03; 95% confidence interval [CI] 1.08-8.50). Providers with little experience treating patients with HIV may not possess the basic knowledge required to manage the disease during pregnancy. Additional educational interventions are needed in low seroprevalence areas to ensure the appropriate treatment of all HIV-positive pregnant patients and to minimize the risk of preventable perinatal transmission.

Effects of Antiretroviral Therapy on Immunity in Patients Infected with HIV

Drug therapy for human immunodeficiency virus (HIV) is highly effective in suppressing viral replication and restoring immune function in patients with HIV. However, this same treatment can also be associated with immunotoxicity. For example, zidovudine and various other antiretroviral agents are capable of causing bone marrow suppression. Agents used to treat opportunistic infections in these individuals, including ganciclovir, foscarnet, and sulfamethoxazole-trimethoprim, can cause additional hematotoxicity. Drug-drug interactions must also be considered and managed in order to control iatrogenic causes of immunotoxicity. In this review, we examine the normal immune response to HIV, and the benefits of antiretroviral therapy in prolonging immune function. We then discuss immune-related adverse effects of drugs used to treat HIV and the opportunistic infections that are common among these patients. Finally, we address in vitro, animal, and clinical evidence of toxicity associated with various combination use of these agents.

Poppers: epidemiology and clinical management of inhaled nitrite abuse

Commonly referred to as "poppers," inhaled nitrites have a long history of abuse. Poppers are rapid-onset, short-acting potent vasodilators that produce a rush characterized by warm sensations and feelings of dizziness. Poppers sometimes are used to facilitate anal intercourse because of their actions on the anal sphincter. Epidemiologically, the frequent use of nitrites by men who have sex with men has led some experts to implicate these chemicals in the pathogenesis of Kaposi's sarcoma and acquired immunodeficiency syndrome. Controlled clinical trials to examine this potential correlation have not been conducted, and the use of nitrites simply may be a marker for other high-risk behaviors such as unprotected sex. Although regulated in the United States, many nitrite compounds and isomers are sold at various venues including bars, bookstores, and over the Internet. Adverse effects associated with these products vary from mild allergic reactions to life-threatening methemoglobinemia. The potential for drug-drug interactions and a propensity toward unsafe sex also exist. Clinicians should be familiar with the populations most likely to abuse these agents and with the clinical effects and management guidelines for acute ingestions.

Reproduction decision making for couples affected by HIV: a review of the literature

Medical issues faced by HIV-affected couples include transmission risks between partners and between mother and child, as well as the technologies and procedures available to reduce those risks. Assisted reproductive techniques discussed are artificial insemination, in vitro fertilization, intracytoplasmic sperm injection, self-insemination, and timed intercourse. It is important that physicians be aware of reproductive options available to couples affected by HIV and be prepared to engage in nonjudgmental dialogue with patients. This review is the result of a literature search performed to identify useful information to counsel HIV-serodiscordant and HIV-seroconcordant couples facing decisions on reproduction.

Noroviruses: agents in outbreaks of acute gastroenteritis

Noroviruses are the most common cause of acute gastroenteritis in the United States and are believed to be the most common cause of food borne illnesses.1 Noroviruses have avoided attention for years due to the difficulty of detection and inability to be cultured. Norovirus outbreaks have major implications for health care workers as they can occur in nursing homes and hospitals. To further complicate the picture, these viruses can infect persons of all ages which is a feature that distinguishes noroviruses from other agents. Factors that contribute to the significant impact of noroviruses include a large human reservoir, low infection dose, and the ability to be transmitted by various routes. This article provides an overview of noroviruses particularly as it relates to health care workers.

Metronidazole-induced pancreatitis in a patient with recurrent vaginal trichomoniasis

Recurrent acute pancreatitis associated with metronidazole developed in a 49-year-old woman who was taking the drug as treatment for vaginal trichomoniasis. The lack of alternative effective therapies for trichomoniasis governed the decision to rechallenge the patient with metronidazole despite a vague history of this reaction on a previous occasion. Six reports of this reaction are found in the literature. The patient was admitted to the hospital 12 hours after taking a single dose of metronidazole. Severe epigastric pain and elevated amylase and lipase concentrations led to the diagnosis of acute pancreatitis, although results of an abdominal ultrasound were unremarkable. The patient made a full recovery. Although this reaction occurs infrequently, this case report illustrates the need to develop additional therapies for treatment of trichomoniasis.

Levofloxacin failure in a patient with pneumococcal pneumonia

OBJECTIVE

To report a case of levofloxacin failure in a patient with a penicillin-sensitive Streptococcus pneumoniae pneumonia.

CASE SUMMARY

A previously healthy, immunocompetent, 53-year-old white man presented with penicillin-sensitive S. pneumoniae pneumonia. The patient was empirically placed on levofloxacin monotherapy, which was continued due to a local penicillin shortage. When the patient failed to improve, further susceptibility testing was ordered. The organism was found to have a penicillin minimum inhibitory concentration (MIC) of 0.023 microgram/mL and a levofloxacin MIC of 6 micrograms/mL. Effective antimicrobial therapy was delayed, as clinicians did not anticipate fluoroquinolone resistance.

DISCUSSION

Newer fluoroquinolones such as levofloxacin have good activity against most S. pneumoniae isolates and are used for the treatment of pneumonia. Although resistance to these agents is rare, it has been reported. Current guidelines from the National Committee for Clinical Laboratory Standards do not recommend initial fluoroquinolone susceptibility testing.

CONCLUSIONS

As fluoroquinolone resistance may not be identified by susceptibility patterns to other antibiotics, early fluoroquinolone susceptibility testing and increased awareness of resistance may aid clinicians in their treatment of pneumococcal disease.

Standardization of the experimental model of Haemophilus ducreyi infection in human subjects

Human volunteers were challenged with Haemophilus ducreyi. Twenty subjects were inoculated with 2 doses (approximately 30 cfu) of live and 1 dose of heat-killed bacteria at 3 sites on the arm. Eight subjects were assigned to biopsy 1 or 4 days after inoculation, and 12 were biopsied after they developed a painful pustular lesion or were followed until disease resolved. Papules developed at 95% of 40 sites infected with live bacteria (95% confidence interval [CI], 83. 1%-99.4%). In 24 sites followed to end point, 27% of the papules resolved, 69% (95% CI, 47.1%-86.6%) evolved into pustules, and 4% remained at the papular stage. Recovery rates of H. ducreyi from surface cultures ranged from 13% to 41%. H. ducreyi was recovered from biopsies of 12 of 15 pustules and 1 of 7 papules, suggesting that H. ducreyi replicates between the papular and pustular stages of disease.

Evaluation of an isogenic hemolysin-deficient mutant in the human model of Haemophilus ducreyi infection

Haemophilus ducreyi causes the genital ulcerative disease chancroid. One putative virulence factor of H. ducreyi is a pore-forming hemolysin that displays toxicity against human fibroblasts and keratinocytes. In order to test the role of the hemolysin in pathogenesis, an isogenic hemolysin-deficient mutant was constructed, designated 35000HP-RSM1. The lipooligosaccharide, outer membrane protein patterns, and growth attributes of 35000HP-RSM1 were identical to its parent, 35000HP. Human subjects were challenged on the upper arm with the isogenic isolates in a double-blinded, randomized, escalating dose-response study. Pustules developed at a similar rate at sites inoculated with the mutant or parent. The cellular infiltrate and bacterial load in lesions were also similar. These results indicate the hemolysin does not play a role in pustule formation. Due to the limitations of this model, the role of the hemolysin at later stages of infection could not be determined.

Prevention of experimental Haemophilus ducreyi infection: a randomized, controlled clinical trial

Human subjects were infected with Haemophilus ducreyi. All subjects developed papules and were randomized to treatment with a single dose of azithromycin (1 g) or ciprofloxacin (500 mg). At weekly intervals, volunteers were reinoculated with H. ducreyi, and drug concentrations were measured in peripheral blood mononuclear cells (PBMC). When papules developed, the subjects were treated with antibiotics and dismissed from the study. Eight of the ciprofloxacin-treated subjects developed papules 1 week after the initial treatment, and the ninth subject developed disease 2 weeks after treatment. The 9 azithromycin-treated subjects developed papules 4-10 weeks (mean, 6.8) after the initial treatment (P < .001). Azithromycin was detected in PBMC for 3-6 weeks (mean, 4). Pre- and posttreatment lesions had histology typical of experimental chancroid or were culture positive. Azithromycin prevents experimental chancroid for nearly 2 months. These findings have implications for strategies to prevent chancroid.

The importance of life-time changes in fluorescence depolarization

The rotational relaxation time, rho, calculated from measurements of fluorescence depolarization, is clearly dependent on the assumed mean life-time, tau, of the excited state. However, variations in tau with experimental conditions (temperature and solvent composition) occur and the effect of such alterations in tau is demonstrated. In particular it should be noted that, unless life-time changes can be excluded, the occurrence of linear plots of reciprocal degree of polarization against the temperature/viscosity ratio does not necessarily indicate the absence of intramolecular freedoms. An attempt to correct for such life-time changes by measurement of the fluorescence intensity is made for the bovine serum albumin-1-dimethyl-aminonaphthalene-5-sulphonyl chloride system. The value of rho/3tau thus obtained for this system at 20 degrees is approx. 4.7, as against approx. 3.4 obtained by several workers in the absence of life-time corrections.