Twice-Daily Dolutegravir Based Antiretroviral Therapy with One Month of Daily Rifapentine and Isoniazid (1HP) for TB Prevention

BACKGROUND

One month of daily rifapentine + isoniazid (1HP) is an effective, ultrashort option for TB prevention in people with HIV (PWH). However, rifapentine may decrease antiretroviral drug concentrations and increase the risk of virologic failure. ACTG A5372 evaluated the effect of 1HP on the pharmacokinetics of twice daily dolutegravir.

METHODS

A5372 was a multicenter, pharmacokinetic study in PWH (≥18 years) already on dolutegravir-containing antiretroviral therapy with HIV RNA < 50 copies/mL. Participants received daily rifapentine/isoniazid (600mg/300mg) for 28 days as part of 1HP. Dolutegravir was increased to 50mg twice daily during 1HP and intensive pharmacokinetic sampling was performed on day 0 (before 1HP) and on the final day of 1HP treatment.

RESULTS

Thirty-two participants (41% female; 66% Black/African; median (Q1, Q3) age 42 (34, 49) years) were included in the pharmacokinetic analysis. Thirty-one of 32 had HIV RNA levels <50 copies/mL at the end of 1HP dosing. One participant had an HIV RNA of 160 copies/mL at day 28, with HIV RNA <50 copies/mL upon repeat testing on day 42. The median (Q1, Q3) dolutegravir trough concentration was 1751 ng/mL (1195, 2542) on day 0 vs. 1987ng/mL (1331, 2278) on day 28 (day 28:day 0 GMR 1.05, [90% CI 0.93-1.2]; p = 0.43). No serious adverse events were reported.

CONCLUSION

Dolutegravir trough concentrations with 50mg twice daily dosing during 1HP treatment were greater than those with standard dose dolutegravir once daily without 1HP. These pharmacokinetic, virologic, and safety data provide support for twice daily dolutegravir use in combination with 1HP for TB prevention.

Effect of Canakinumab vs Placebo on Survival Without Invasive Mechanical Ventilation in Patients Hospitalized With Severe COVID-19: A Randomized Clinical Trial

Importance

Effective treatments for patients with severe COVID-19 are needed.

Objective

To evaluate the efficacy of canakinumab, an anti-interleukin-1β antibody, in patients hospitalized with severe COVID-19.

Design, Setting, and Participants

This randomized, double-blind, placebo-controlled phase 3 trial was conducted at 39 hospitals in Europe and the United States. A total of 454 hospitalized patients with COVID-19 pneumonia, hypoxia (not requiring invasive mechanical ventilation [IMV]), and systemic hyperinflammation defined by increased blood concentrations of C-reactive protein or ferritin were enrolled between April 30 and August 17, 2020, with the last assessment of the primary end point on September 22, 2020.

Intervention

Patients were randomly assigned 1:1 to receive a single intravenous infusion of canakinumab (450 mg for body weight of 40-<60 kg, 600 mg for 60-80 kg, and 750 mg for >80 kg; n = 227) or placebo (n = 227).

Main Outcomes and Measures

The primary outcome was survival without IMV from day 3 to day 29. Secondary outcomes were COVID-19-related mortality, measurements of biomarkers of systemic hyperinflammation, and safety evaluations.

Results

Among 454 patients who were randomized (median age, 59 years; 187 women [41.2%]), 417 (91.9%) completed day 29 of the trial. Between days 3 and 29, 198 of 223 patients (88.8%) survived without requiring IMV in the canakinumab group and 191 of 223 (85.7%) in the placebo group, with a rate difference of 3.1% (95% CI, -3.1% to 9.3%) and an odds ratio of 1.39 (95% CI, 0.76 to 2.54; P = .29). COVID-19-related mortality occurred in 11 of 223 patients (4.9%) in the canakinumab group vs 16 of 222 (7.2%) in the placebo group, with a rate difference of -2.3% (95% CI, -6.7% to 2.2%) and an odds ratio of 0.67 (95% CI, 0.30 to 1.50). Serious adverse events were observed in 36 of 225 patients (16%) treated with canakinumab vs 46 of 223 (20.6%) who received placebo.

Conclusions and Relevance

Among patients hospitalized with severe COVID-19, treatment with canakinumab, compared with placebo, did not significantly increase the likelihood of survival without IMV at day 29.

Trial Registration

ClinicalTrials.gov Identifier: NCT04362813.

1048. Weight Gain after Initiation of Anti-Retroviral Therapy in Acute HIV-1

Background

Background: Excess weight gain with integrase strand transfer inhibitors (INSTIs) has been reported in some people with chronic HIV. In antiretroviral therapy (ART)-naïve people, greater weight gain over 18 months was reported with dolutegravir than other agents. We hypothesized that initiating an INSTI-based regimen during acute HIV infection (AHI) would result in more weight gain than a non-INSTI-based regimen, and INSTIs other than elvitegravir (EVG) would be associated with greater weight gain than EVG.

Methods

Methods: We performed a retrospective, observational, single center chart review analysis of adults with AHI (Feibig Stages 1-5) who were initiated on ART and followed for 48 (+/- 12) weeks. Changes in weight between people on INSTI- vs non-INSTI regimens were compared, and in a subgroup analysis, EVG vs non-EVG and tenofovir alafenamide (TAF) vs non-TAF were compared. Chi-square, t-test, or Wilcoxon Rank Sum test were used, when appropriate.

Results

Results: Baseline characteristics of the 61 participants are shown in Table 1. Overall median (IQR) weight change was 4.53 (1.22-8.36; within-group P&lt; 0.0001) kg (Figure 1). Median weight change in 58 people initiated on INSTI was 4.66 (1.22-8.43; P&lt; 0.0001) kg vs 1.64 (-3.08-6.57; P=0.75) kg in 3 people not on INSTI (between-group P= 0.33). Median weight change on EVG was 4.40 (0.91-6.71; P&lt; 0.0001) kg vs 7.10 (4.97-13.15; P= 0.0001) kg for non-EVG INSTIs (between-group P= 0.008, Figure 2). Median weight change on TAF (n=33) was 2.66 (0.81-7.53; P= 0.002) kg vs 5.31 (3.72-9.34; P &lt; 0.0001) kg in non-TAF (n=25) recipients (between-group P= 0.06). Lower baseline CD4+ T cell count correlated with greater weight gain (P= 0.012). No association between weight gain and race (P= 0.930) or gender (P= 0.379) was noted.

Baseline characteristics and median weight change (kg) from baseline

Conclusion

People initiating ART during AHI gained weight over 48 weeks, with persons taking INSTIs gaining more weight, though this finding did not reach statistical significance due to small sample size. Amongst INSTI-treated persons, those not on EVG gained more weight than those on EVG. While the benefits of starting ART during AHI on immune system preservation and reservoir should not be underscored, risk and consequences of weight gain following ART initiation should be discussed when initiating ART during AHI.

Disclosures

Jordan Lake, MD, Gilead Sciences (Grant/Research Support, Scientific Research Study Investigator)

376. Effect of Parasitic Infections on Gut Epithelial Barrier and Immune Activation among Foreign-Born HIV-infected Patients

Background

Strongyloides stercoralis often causes an asymptomatic infection despite continuous autoinfection for the lifetime of the host. Both HIV and recurrent enteric parasitic infections cause gut damage and increased microbial translocation, but little is known about the effects of co-infection. We aimed to evaluate changes in immune activation, mucosal damage, and microbial translocation in people with HIV-1 (PWH) and parasite co-infection.

Methods

In this pilot prospective cohort study, we enrolled foreign-born PWH on suppressive antiretroviral therapy (ART) in an ambulatory clinic in Houston, Texas. We evaluated serum Strongyloides IgG using ELISA with an S. stercoralis-specific recombinant protein. Intestinal fatty acid-binding protein (I-FABP), soluble CD14 (sCD14), sCD163, IL-6, and sTNFRII were analyzed as markers of enterocyte turnover, inflammation, and immune activation. Non-parametric tests were used for analysis.

Results

52 participants born in 14 countries were enrolled February–March 2019. Median CD4 count was 464/uL [95% CI 315–598]. Fourteen (27%) were positive for Strongyloides IgG. Strongyloides IgG levels correlated positively with sCD14 levels [r=0.36; P = 0.008]. Strongyloides+ participants had significantly higher sCD14 levels compared with Strongyloides− participants [1.67 vs. 1.48 μg/mL, P = 0.031]. Among the Strongyloides+ participants, Strongyloides IgG levels correlated with sCD163 levels [r=0.65, P = 0.026]. There were no difference in the other biomarkers. Logistical regression analysis showed that predictors of Strongyloides+ include absolute eosinophil count (AEC) (OR 1.45 for every 100 increase of AEC [95% CI: 1.02, 2.15; P = 0.047]). CD4 count, number of years living in the United States, country of origin, and years from HIV diagnosis were not associated with test positivity.

Conclusion

Strongyloides co-infection is common among foreign-born PWH and may contribute to chronic monocyte/macrophage activation, a predictor of morbidity and mortality in PWH. Future directions include stool PCR confirmation of these infections, continued enrollment, and follow-up assays 6 months after treatment of Strongyloides to determine the impact on inflammation and risk of co-morbidities.

Disclosures

All authors: No reported disclosures.

2517. Oral Fecal Microbiota Transplantation Increases Gut Microbiome Diversity and Alters the Microbiome Distribution in People with HIV

Background

Reduced microbiota diversity (dysbiosis) in people with HIV (PWH) can damage the intestinal barrier and increase microbial translocation, resulting in inflammation, a driver of morbidity and mortality. We hypothesized that fecal microbiota transplants (FMT) would reverse dysbiosis in PWH.

Methods

We administered 6 weekly oral doses of a novel lyophilized fecal microbiota product from 2 healthy donors to 6 men who have sex with men with HIV on suppressive ART. Shotgun sequencing on stool before, after 6 weekly FMT, and 20 weeks after the last FMT (Weeks 0, 6 and 26), and from donors, was performed to determine bacterial community profiles. Biomarkers were measured by Luminex assays and ELISAs. All comparisons used Wilcoxon matched-pairs signed rank test.

Results

Median age at Week 0 was 41 years, CD4+ T-cell count 504 cells/mm³, VL < 20 copies/mL. Mean α diversity by observed species index increased from Week 0 to 6 (61.2 to 70.2, P = 0.29; Figure 1) and decreased by Week 26 (70.2 to 52.2, P = 0.33) to be similar to the donors’ (63.5, P = 0.86). Microbiome distribution by principal component analysis shifted toward the donors’ distribution in most participants at Week 6 but shifted away by Week 26 (Figure 2). Biomarkers did not change significantly during the study. PID3, with HIV > 35 years, had chronic constipation that resolved with FMT with a large shift in distribution but recurred at Week 26. Fusobacterium gonidiaformans, Porphyromonas somerae, and Haemophilus parainfluenzae comprised 27% of his microbiome at Week 0 but 0.73% at Week 6; untyped Bacteroides comprised 35% at Week 6. I-FABP (6,899 to 2,736 pg/mL), sCD14 (1.67 to 1.31 μg/mL), IL-6 (1.51 to 1.13 pg/mL) and sTNFRII (11,659 to 8,300 pg/mL) levels decreased in PID3; Week 0 levels in PID3 were higher than in other recipients. No related serious adverse events occurred.

Conclusion

Weekly FMT resulted in increased intestinal microbiome α diversity and a shift in microbiome distribution in most participants. These changes did not persist after stopping FMT. PWH with long-term HIV and/or greater inflammation or gut damage may be most likely to benefit from FMT. The effects of recurrent FMT were transient, suggesting longer duration of treatment or intermittent FMT boosting may be required to maintain its benefits.

Disclosures

All authors: No reported disclosures.

Treatment-Naïve HIV-Infected Patients Have Fewer Gut-Homing β7 Memory CD4 T Cells than Healthy Controls

OBJECTIVES

The integrin α4β7 is the gut-homing receptor for lymphocytes. It also is an important co-receptor for human immunodeficiency virus (HIV) via glycoprotein (gp)120 binding. Depletion of gut cluster of differentiation (CD)4 T cells is linked to chronic inflammation in patients with HIV; however, measuring CD4 cells in the gut is invasive and not routine. As such, establishing a peripheral marker for CD4 depletion of the gut is needed. We hypothesized that α4β7 CD4 T cells are depleted in the peripheral blood of treatment-naïve patients with HIV compared with healthy controls.

METHODS

The study groups were treatment-naïve patients with HIV and uninfected controls. Subjects were included if they were 18 years or older with no history of opportunistic infections, active tuberculosis, or cancer. We collected peripheral blood and examined on whole blood using flow cytometry for the following cell surface markers: CD4, CD45RO, chemokine receptor type 5, C-X-C chemokine receptor type 4 (CXCR4), and the integrin β7. We collected demographic information, including age, sex, and ethnicity, as well as viral load (VL) and CD4 count. Two-sample t tests and Fisher exact tests were used to compare the differences between the two groups. Spearman correlation coefficients were calculated between CD4 count and log10^- VL and percentage of CD4⁺/CD45RO⁺/β7⁺ and log10^- VL in patients.

RESULTS

Twenty-two subjects were enrolled in the study (12 patients with HIV and 10 controls). There were no differences in age or sex between the two groups. There were more Hispanics and fewer Asians in the group comprising patients with HIV compared with the control group (7 vs 2 and 0 vs 4, P = 0.05, respectively). Patients infected with HIV had significantly lower frequencies of CD4⁺/CD45RO⁺/β7⁺ cells (median 12%, range 5-18 compared with uninfected controls: median 20%, range 11-26, P = 0.0007). There was a statistically significant difference in the percentage of CD4⁺/CD45RO⁺/C-X-C chemokine receptor type 4⁺ cells between patients (72%, range 60%-91%) compared with controls (79%, range 72%-94%, P = 0.04). The percentage of CD4⁺/CD45RO⁺/chemokine receptor type 5⁺ did not differ between the group of patients with HIV and the control groups (22%, range 11%-57% vs 27%, range 14%-31%; P = 0.8, respectively). There was no correlation between percentage of CD4⁺/CD45RO⁺/β⁺ cells and log10^- VL as measured by the Spearman correlation coefficient (r = 0.05, P = 0.88) in patients infected with HIV.

CONCLUSIONS

Memory CD4 β7⁺ cells are reduced significantly in the peripheral blood of untreated patients infected with HIV, which could be used as a noninvasive indicator of intestinal CD4 T cell loss and recovery. Further studies are needed to examine whether depletion of these CD4⁺/CD45RO⁺/β7⁺ cells in the peripheral blood parallels depletion in the gut of treatment-naïve patients with HIV and whether levels return to control levels after treatment.

Evaluation of Xpert MTB/RIF Versus AFB Smear and Culture to Identify Pulmonary Tuberculosis in Patients With Suspected Tuberculosis From Low and Higher Prevalence Settings

BACKGROUND

The Xpert MTB/RIF (Xpert) assay is a rapid nucleic acid amplification test widely used in settings of high tuberculosis prevalence to detect tuberculosis as well asrpoBmutations associated with rifampin resistance. Data are needed on the diagnostic performance of Xpert in lower-prevalence settings to inform appropriate use for both tuberculosis detection and the need for respiratory isolation.

METHODS

Xpert was compared to 2 sputum samples, each evaluated with acid-fast bacilli (AFB) smear and mycobacterial culture using liquid and solid culture media, from participants with suspected pulmonary tuberculosis from the United States, Brazil, and South Africa.

RESULTS

Of 992 participants enrolled with evaluable results, 22% had culture-confirmed tuberculosis. In 638 (64%) US participants, 1 Xpert result demonstrated sensitivity of 85.2% (96.7% in participants with AFB smear-positive [AFB(+)] sputum, 59.3% with AFB smear-negative [AFB(-)] sputum), specificity of 99.2%, negative predictive value (NPV) of 97.6%, and positive predictive value of 94.9%. Results did not differ between higher- and low-prevalence settings. A second Xpert assay increased overall sensitivity to 91.1% (100% if AFB(+), 71.4% if AFB(-)), with specificity of 98.9%. In US participants, a single negative Xpert result predicted the absence of AFB(+)/culture-positive tuberculosis with an NPV of 99.7%; NPV of 2 Xpert assays was 100%, suggesting a role in removing patients from airborne infection isolation. Xpert detected tuberculosis DNA and mutations associated with rifampin resistance in 5 of 7 participants with rifampin-resistant, culture-positive tuberculosis. Specificity for rifampin resistance was 99.5% and NPV was 98.9%.

CONCLUSIONS

In the United States, Xpert testing performed comparably to 2 higher-tuberculosis-prevalence settings. These data support the use of Xpert in the initial evaluation of tuberculosis suspects and in algorithms assessing need for respiratory isolation.

Poly-tobacco use among HIV-positive smokers: implications for smoking cessation efforts

INTRODUCTION

Poly-tobacco use is defined as cigarette and other tobacco consumption with either product used daily or nondaily. While concurrent use of different types of tobacco has been documented within the general population, less is known about poly-tobacco use among HIV-positive smokers and its impact on smoking cessation efforts.

OBJECTIVE

To characterize the profile of poly-tobacco users (PTU) in a sample of HIV-positive smokers participating in a cessation program.

METHODS

The study sample consisted of 474 HIV-positive smokers enrolled in a 2-group randomized controlled trial of cigarette smoking cessation comparing a cell phone-based intervention to usual care. Prevalence was determined, and risk factors for poly-tobacco use were evaluated using logistic regression.

RESULTS

In this cohort of HIV-positive cigarette smokers, 21.6% of participants were PTU, with cigars (73.4%) the most common tobacco product consumed. Among PTU, 73.5% used other form(s) of tobacco some days, and 26.5% use them every day. Perceived discrimination and unemployment were significantly associated with poly-tobacco use after adjusting for other demographic, behavioral, and psychosocial factors. Analysis showed that participants in the cell phone group (vs. usual care) were more likely to report 24-hr abstinence, both among monocigarette users (16.6% vs. 6.3%, p < .001) and PTU (18.5% vs. 0%, p < .001).

CONCLUSION

Poly-tobacco use prevalence among adult HIV-positive smokers was considerably higher than in the general population. Special attention must be placed on concurrent use of cigarettes and cigars among HIV-positive smokers. Because PTU are a unique population less likely to succeed in brief smoking cessation interventions, effective cessation programs are needed.

Factors associated with past research participation among low-income persons living with HIV

We described influences on past research participation among low-income persons living with HIV (PLWH) and examined whether such influences differed by study type. We analyzed a convenience sample of individuals from a large, urban clinic specializing in treating low-income PLWH. Using a computer-assisted survey, we elicited perceptions of research and participating in research, barriers, benefits, "trigger" influences, and self-efficacy in participating in research. Of 193 participants, we excluded 14 who did not identify any type of study participation, and 17 who identified "other" as study type, resulting in 162 cases for analysis. We compared results among four groups (i.e., 6 comparisons): past medical participants (n=36, 22%), past behavioral participants (n=49, 30%), individuals with no past research participation (n=52, 32%), and persons who had participated in both medical and behavioral studies (n=25, 15%). Data were analyzed using chi-square tests for categorical variables and ANOVA for continuous variables. We employed a multinomial probit (MNP) model to examine the association of multiple factors with the outcome. Confidence in ability to keep appointments, and worry about being a 'guinea pig' showed statistical differences in bivariate analyses. The MNP regression analysis showed differences between and across all 6 comparison groups. Fewer differences were seen across groupings of medical participants, behavioral participants, and those with no past research experience, than in comparisons with the medical-behavioral group. In the MNP regression model 'age' and level of certainty regarding 'keeping yourself from being a guinea pig' showed significant differences between past medical participants and past behavioral participants.

Evaluation of Subcutaneous Proleukin (interleukin-2) in a Randomized International Trial (ESPRIT): geographical and gender differences in the baseline characteristics of participants

BACKGROUND

ESPRIT, is a phase III, open-label, randomized, international clinical trial evaluating the effects of subcutaneous recombinant interleukin-2 (rIL-2) plus antiretroviral therapy (ART) versus ART alone on HIV-disease progression and death in HIV-1-infected individuals with CD4+ T-cells > or =300 cells/microL.

OBJECTIVES

To describe the baseline characteristics of participants randomized to ESPRIT overall and by geographic location.

METHOD

Baseline characteristics of randomized participants were summarized by region.

RESULTS

4,150 patients were enrolled in ESPRIT from 254 sites in 25 countries. 41%, 27%, 16%, 11%, and 5% were enrolled in Europe, North America, South America, Asia, and Australia, respectively. The median age was 40 years, 81% were men, and 76%, 11%, and 9% were Caucasian, Asian, and African American or African, respectively. 44% of women enrolled (n = 769) were enrolled in Thailand and Argentina. Overall, 55% and 38% of the cohort acquired HIV through male homosexual and heterosexual contact, respectively. 25% had a prior history of AIDS-defining illness; Pneumocystis jirovecii pneumonia, M. tuberculosis, and esophageal candida were most commonly reported. Median nadir and baseline CD4+ T-cell counts were 199 and 458 cells/muL, respectively. 6% and 13% were hepatitis B or C virus coinfected, respectively. Median duration of antiretroviral therapy (ART) was 4.2 years; the longest median duration was in Australia (5.2 years) and the shortest was in Asia (2.3 years). 17%, 13%, and 69% of participants began ART before 1995, between 1996 and 1997, and from 1998 onward, respectively. 86% used ART from two or more ART classes, with 49% using a protease inhibitor-based regimen and 46% using a nonnucleoside reverse transcriptase inhibitor-based regimen. 78% had plasma HIV RNA below detection (<500 cp/mL).

CONCLUSION

ESPRIT has enrolled a diverse population of HIV-infected individuals including large populations of women and patients of African-American/African and Asian ethnicity often underrepresented in HIV research. As a consequence, the results of the study may have wide global applicability.

Increasing access to smoking cessation treatment in a low-income, HIV-positive population: the feasibility of using cellular telephones

This study examined the feasibility of using cellular telephones to improve access to smoking cessation counseling in a low-income, HIV-positive population. Two pilot studies were conducted: (a). A survey of interest and barriers in participating in a smoking cessation intervention (n=49) and (b). a cellular telephone smoking cessation intervention in which participants were provided with free cellular telephones and received six telephone counseling sessions over a 2-week period (n=20). A primary care clinic serving a multiethnic, medically indigent, HIV-positive population served as the setting. Demographics and smoking status were assessed by self-report and expired-air carbon monoxide testing. In study 1, participants reported multiple barriers to participating in a smoking cessation intervention, including transportation, transience, and telephone availability. However, they also reported a high level of interest in participating in a smoking cessation intervention, with the greatest interest in a cellular telephone intervention. In study 2, 19 of the 20 participants successfully completed 2 weeks of smoking cessation counseling with a 93% (106 of 114 calls) contact rate. A total of 19 participants made a quit attempt, and the 2-week end of treatment point-prevalence abstinence rate was 75%. The provision of cellular telephones allowed for the implementation of a proactive telephone smoking cessation intervention providing an underserved population with access to care. Cellular telephones also may provide unique benefits because of the intensity of counseling and support provided as well as the ability to provide counseling in real-world, real-time situations (in vivo counseling).

Short‐Term Safety and Antiretroviral Activity of T‐1249, a Second‐Generation Fusion Inhibitor of HIV

T-1249 is a 39-aa synthetic peptide that inhibits fusion of human immunodeficiency virus (HIV) to the host target cell. A 14-day open-label, phase 1/2 dose-escalation monotherapy study of the safety and antiretroviral activity of T-1249 was performed on 115 HIV-1-infected adults. At baseline, the majority of the patients had advanced HIV disease (baseline median CD4(+) cell count, 57 cells/microL) and had extensive pretreatment (i.e., pre-T-1249) experience with antiretroviral medications (median, 11 antiretroviral drugs). Patients received T-1249 monotherapy by subcutaneous injection, for 14 days, at doses ranging from 6.25 to 192 mg/day. T-1249 was generally well tolerated, and no dose-limiting toxicity was identified. Injection-site reactions were the most commonly reported adverse event (57%). Dose-dependent decreases in plasma HIV-1 RNA load were observed; the median maximum change from baseline across dose groups ranged from -0.29 log(10) copies/mL (95% confidence interval [CI], -0.43 to -0.05 log(10) copies/mL) for the lowest dose to -1.96 log(10) copies/mL (95% CI, -2.02 to -1.37 copies/mL) for the highest dose. These results indicate that T-1249 is a potent new therapeutic agent for HIV-1 infection.

Persistence of immunity and seroprotection 4 years after a primary vaccination schedule with a Hansenula polymorpha recombinant hepatitis B vaccine

To evaluate the persistence of the immune response in a population of healthy volunteers that had been vaccinated with a new Hansenula polymorpha recombinant hepatitis B vaccine in a previous clinical study 4 years before, we measured the titre of anti-HBs. All, but one of the evaluated volunteers remained protected. None of them had experienced any adverse event related to the vaccine from the moment of immunization, to the present. The vaccine proved to be immunogenic and to confer long-term protection in this group.

HEp-2 cell-adherent Escherichia coli and intestinal secretory immune response to human immunodeficiency virus (HIV) in outpatients with HIV-associated diarrhea

HEp-2 cell-adherent Escherichia coli and the human immunodeficiency virus (HIV) itself have recently been incriminated as causes of chronic HIV-associated diarrhea. This study sought to determine the prevalence of these two agents among HIV-infected patients with diarrhea in an outpatient setting in the United States and to compare their prevalence to that of other commonly recognized enteropathogens known to be present in this population. HEp-2 cell-adherent E. coli was found in 20 of 83 (24.1%) patients with diarrhea. A diffuse pattern of adherence was the most common, found in 14 of 20 (70%) patients, followed by a localized adherence pattern (6 of 20; 30%). An intestinal secretory immune response against the p24 antigen of HIV was found in 9 of 34 (27.5%) patients with HIV-associated diarrhea. The following pathogens or products were also detected in lower frequencies: Cryptosporidium spp. (10.8%), Clostridium difficile toxin (8.8%), microsporidia (6%), Isospora belli (3.6%), Blastocystis hominis (2.4%), Giardia spp. (1.2%), Salmonella spp. (1.2%), and Mycobacterium spp. (1.2%). The role of HEp-2 cell-adherent E. coli and HIV enteric infections in patients with HIV-associated diarrhea deserves further study.

Study to determine the ability of clinical laboratories to detect antimicrobial-resistant Enterococcus spp. in Buenos Aires, Argentina

Few reports of vancomycin-resistant enterococci have appeared outside the USA. Therefore, we evaluated the ability of five laboratories in Buenos Aires, Argentina, to perform susceptibility testing using the disk diffusion method. Laboratories had difficulty identifying the low- and intermediate-level vancomycin-resistant phenotypes. This suggests that the disk diffusion method used by laboratories abroad may fail to detect some vancomycin-resistant enterococci.