Brucellar Endocarditis of the Tricuspid Valve: A Case Report and Review of the Literature.

Brucellar endocarditis is a rare entity commonly described as a severe disease associated with high mortality and generally requiring valve surgery for cure. Right-sided endocarditis, a very uncommon presentation of brucellosis, may be associated with a better prognosis. We describe the case of a 72-year-old woman admitted to our institution with a persistent fever and multiple pulmonary infiltrates. Transthoracic echocardiography and serologic tests led to the diagnosis of brucellar tricuspid endocarditis. The patient responded favorably to antibiotic treatment alone and did not need surgery. Prolonged antibiotic therapy with a combination of drugs active on intracellular microorganisms in the absence of surgical treatment could be effective in brucellar tricuspid endocarditis when the valve is not severely damaged.

Vaccine-Induced Subacute Thyroiditis (De Quervain's) after mRNA Vaccine against SARS-CoV-2: A Case Report and Systematic Review.

De Quervain's thyroiditis, sometimes referred to as subacute thyroiditis (SAT), is the most common granulomatous disease of the thyroid, typically found after a viral infection in middle-aged women. The mRNA encoding for the angiotensin-converting enzyme-2 (ACE-2) receptor is expressed in follicular thyroid cells, making them a potential target for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides infection, SARS-CoV-2 vaccines have also been implicated in SAT pathogenesis. We present a case of a woman developing SAT following vaccination with Comirnaty by Pfizer Inc. (New-York, USA). We performed a systematic review of similar cases available in the literature to provide a better understanding of the topic. We searched the databases PubMed and Embase and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Patient records were then sorted according to the type of administered vaccine and a statistical analysis of the extracted data was performed. No statistically significant difference between mRNA vaccines and other vaccines in inducing SAT was found, nor was any found in terms of patient demographics, symptoms at presentation, initial, or follow-up blood tests. In our case report, we described the possible association between SARS-CoV-2 mRNA-based vaccine Comirnaty and SAT.

Synergy Between Vitamin D and Sex Hormones in Respiratory Functionality of Patients Affected by COVID-19.

The outcome of COVID-19 appears to be influenced by vitamin D status of population. Although epidemiological data indicate that COVID-19 produces more severe symptoms and higher mortality in elderly in comparison to young patients and in men in comparison to women to date sex and age differences in vitamin D status in infected patients have not been evaluated yet. In this study we evaluated the levels of circulating 25(OH)D in patients hospitalized for COVID-19 divided accordingly to their sex and age. We also correlated 25(OH)D levels with patient's respiratory status (i.e., PaO2/FiO2 ratio) and with sex hormones plasma levels to analyze the potential relationship of these parameters. We found no significant differences in plasma levels of 25(OH)D between pre- and post-menopausal female patients and age matched male patients. Interestingly, the 25(OH)D plasma levels positively correlated to PaO2/FiO2 ratio only in young patients, regardless of their sex. We also found a significantly positive correlation between 17ß-estradiol and 25(OH)D in elderly women and between testosterone and 25(OH)D in elderly men, supporting the role of sex hormones in maintaining 25(OH)D levels. In conclusion, we suggest that a synergy between vitamin D and sex hormones could contribute to the age-related outcome of COVID-19.

Risk and predictive factors of prolonged viral RNA shedding in upper respiratory specimens in a large cohort of COVID-19 patients admitted to an Italian reference hospital.

BACKGROUND: Limited data are available about the predictors and outcomes associated with prolonged SARS-CoV-2 RNA shedding (VS). METHODS: A retrospective study including COVID-19 patients admitted to an Italian hospital between March 1 and July 1, 2020. Predictors of viral clearance (VC) and prolonged VS from the upper respiratory tract were assessed by Poisson regression and logistic regression analyses. The causal relation between VS and clinical outcomes was evaluated through an inverse probability weighted Cox model. RESULTS: The study included 536 subjects. The median duration of VS from symptoms onset was 18 days. The estimated 30-day probability of VC was 70.2%. Patients with comorbidities, lymphopenia at hospital admission, or moderate/severe respiratory disease had a lower chance of VC. The development of moderate/severe respiratory failure, delayed hospital admission after symptoms onset, baseline comorbidities, or D-dimer >1000ng/mL at admission independently predicted prolonged VS. The achievement of VC doubled the chance of clinical recovery and reduced the probability of death/mechanical ventilation. CONCLUSIONS: Respiratory disease severity, comorbidities, delayed hospital admission and inflammatory markers negatively predicted VC, which resulted to be associated with better clinical outcomes. These findings highlight the importance of prompt hospitalization of symptomatic patients, especially where signs of severity or comorbidities are present.

Frequency and Duration of SARS-CoV-2 Shedding in Oral Fluid Samples Assessed by a Modified Commercial Rapid Molecular Assay.

BACKGROUND: RT-PCR on nasopharyngeal (NPS)/oropharyngeal swabs is the gold standard for diagnosis of SARS-CoV-2 infection and viral load monitoring. Oral fluid (OF) is an alternate clinical sample, easy and safer to collect and could be useful for COVID-19 diagnosis, monitoring viral load and shedding. METHODS: Optimal assay conditions and analytical sensitivity were established for the commercial Simplexa™ COVID-19 Direct assay adapted to OF matrix. The assay was used to test 337 OF and NPS specimens collected in parallel from 164 hospitalized patients; 50 bronchoalveolar lavage (BAL) specimens from a subgroup of severe COVID-19 cases were also analysed. RESULTS: Using Simplexa™ COVID-19 Direct on OF matrix, 100% analytical detection down to 1 TCID50/mL (corresponding to 4 × 103 copies (cp)/mL) was observed. No crossreaction with other viruses transmitted through the respiratory toute was observed. Parallel testing of 337 OF and NPS samples showed highly concordant results (κ = 0.831; 95 % CI = 0.771-0.891), and high correlation of Ct values (r = 0.921; p < 0.0001). High concordance and elevated correlation was observed also between OF and BAL. Prolonged viral RNA shedding was observed up to 100 days from symptoms onset (DSO), with 32% and 29% positivity observed in OF and NPS samples, respectively, collected between 60 and 100 DSO. CONCLUSIONS: Simplexa™ COVID-19 Direct assays on OF have high sensitivity and specificity to detect SARS-CoV-2 RNA and provide an alternative to NPS for diagnosis and monitoring SARS-CoV-2 shedding.

Probiotics and infective endocarditis in patients with hereditary hemorrhagic telangiectasia: a clinical case and a review of the literature.

BACKGROUND: In the last decades, probiotics have been widely used as food supplements because of their putative beneficial health effects. They are generally considered safe but rare reports of serious infections caused by bacteria included in the definition of probiotics raise concerns on their potential pathogenic role in patients with particular predisposing factors. Patients with hereditary hemorrhagic telangiectasia (HHT) are exposed to infections because of telangiectasias and arteriovenous malformations (AVMs). We describe what is, to our knowledge, the first case of infective endocarditis (IE) caused by Lactobacillus rhamnosus in a patient with HHT. A systematic review of the relevant medical literature is presented. CASE PRESENTATION: A patient with HHT and an aortic bioprosthesis was admitted because of prolonged fever not responding to antibiotics. The patient had a history of repeated serious infections with hospitalizations and prolonged use of antibiotics, and used to assume large amounts of different commercial products containing probiotics. Weeks before the onset of symptoms the patient had been treated with nasal packings and with surgical closure of a nasal bleeding site because of recurrent epistaxis. A diagnosis of IE of the aortic bioprosthesis was made. All blood coltures were positive for L. rhamnosus. The patients responded to a cycle of 6 weeks of amoxicillin/clavulanate plus gentamicin. A systematic review of IE linked to consumption of probiotics, and of infective endocarditis in patients with HHT was conducted. 10 cases of IE linked to probiotics consumption and 6 cases of IE in patients with HHT were found. CONCLUSIONS: Consumption of probiotics can pose a risk of serious infections in patients with particular predisposing factors. Patients with HHT can be considered at risk because of their predisposition to infections. Prophylaxis with antibiotics before nasal packings in patients with HHT can be considered.

Simplification to co-formulated rilpivirine/emtricitabine/tenofovir in virologically suppressed patients: Data from a multicenter cohort.

BACKGROUND: To assess efficacy and safety of treatment simplification to co-formulated Rilpivirine/Emtricitabine/Tenofovir (RPV/FTC/TDF) in virologically suppressed patients. MATERIALS AND METHODS: Endpoints of the analysis were: (a) treatment discontinuation of RPV/FTC/TDF for any reasons and (b) occurrence of virological failure (VF) defined as confirmed HIV-RNA >50 cp/mL). RESULTS: Overall, 508 patients from five Italian reference centres were included: male gender 71.9%; median age 47 years (IQR 40-52); IVDU as HIV risk 17.7%; HCV-AB positive 23.4%; CDC-C stage 17.5%; median CD4 cells/µL at switch 655 (IQR: 487-843); median number of previous regimens three (IQR 2-7). In a median follow-up of 196 days (IQR: 84-287), 31 patients discontinued RPV/FTC/TDF (virological failure n=5, hypersensitivity reaction n=2, GI-toxicity n=6, liver toxicity n=1, CNS-toxicity n=4, kidney toxicity n=5, patient's decision/lost in follow-up n=10). Moreover, VF occurred in eight patients (five discontinued regimen, while three remained on RPV/FTC/TDF). At survival analysis, the probabilities of treatment discontinuation or VF were 5.5% and 1.2% at 6 months, 13.2% and 2.8% at 12 months, respectively (Figure 1). At adjusted Cox model, factors associated with discontinuation were: <200 CD4 cells/µL at switch (HR 5.3, 95% CI 1.1-25.9, p=0.038), number of pre-switch regimens (for each extra regimen: HR 1.05, 95% CI 1.01-1.10, p=0.024), male gender (HR 0.4, 95% CI 0.2-0.9, p=0.032). Only the number of pre-switch regimens was associated with VF (HR 1.13, 95% CI 1.06-1.21, p=0.001). Type of pre-switch regimen was not associated with discontinuation or failure, but no VF was observed if switching from co-formulated Efavirenz/FTC/TDF or from Raltegravir containing regimens. Switching to RPV/FTC/TDF led to significant improvement in fasting lipids levels: the decrease in cholesterol, LDL and triglycerides was observed switching from any regimen, but was more marked from boosted PI. In contrast, a moderate increase in transaminase (switching from all regimens except NNRTI-containing) and creatinine (except from TDF-containing regimens) were observed. CONCLUSIONS: Our data suggest that switching to RPV/FTC/TDF in virologically suppressed patients could be a good strategy with low risk of virological failure or treatment discontinuation; the switch is also associated with significant improvement in lipid profile.

A very low geno2pheno false positive rate is associated with poor viro-immunological response in drug-naïve patients starting a first-line HAART.

BACKGROUND: We previously found that a very low geno2pheno false positive rate (FPR ≤ 2%) defines a viral population associated with low CD4 cell count and the highest amount of X4-quasispecies. In this study, we aimed at evaluating whether FPR ≤ 2% might impact on the viro-immunological response in HIV-1 infected patients starting a first-line HAART. METHODS: The analysis was performed on 305 HIV-1 B subtype infected drug-naïve patients who started their first-line HAART. Baseline FPR (%) values were stratified according to the following ranges: ≤ 2; 2-5; 5-10; 10-20; 20-60; >60. The impact of genotypically-inferred tropism on the time to achieve immunological reconstitution (a CD4 cell count gain from HAART initiation ≥ 150 cells/mm(3)) and on the time to achieve virological success (the first HIV-RNA measurement <50 copies/mL from HAART initiation) was evaluated by survival analyses. RESULTS: Overall, at therapy start, 27% of patients had FPR ≤ 10 (6%, FPR ≤ 2; 7%, FPR 2-5; 14%, FPR 5-10). By 12 months of therapy the rate of immunological reconstitution was overall 75.5%, and it was significantly lower for FPR ≤ 2 (54.1%) in comparison to other FPR ranks (78.8%, FPR 2-5; 77.5%, FPR 5-10; 71.7%, FPR 10-20; 81.8%, FPR 20-60; 75.1%, FPR >60; p = 0.008). The overall proportion of patients achieving virological success was 95.5% by 12 months of therapy. Multivariable Cox analyses showed that patients having pre-HAART FPR ≤ 2% had a significant lower relative adjusted hazard [95% C.I.] both to achieve immunological reconstitution (0.37 [0.20-0.71], p = 0.003) and to achieve virological success (0.50 [0.26-0.94], p = 0.031) than those with pre-HAART FPR >60%. CONCLUSIONS: Beyond the genotypically-inferred tropism determination, FPR ≤ 2% predicts both a poor immunological reconstitution and a lower virological response in drug-naïve patients who started their first-line therapy. This parameter could be useful to identify patients potentially with less chance of achieving adequate immunological reconstitution and virological undetectability.

Reliability and clinical relevance of the HIV-1 drug resistance test in patients with low viremia levels.

BACKGROUND: We evaluated reliability and clinical usefulness of genotypic resistance testing (GRT) in patients for whom combination antiretroviral therapy (cART) was unsuccessful with viremia levels 50-1000 copies/mL, for whom GRT is generally not recommended by current guidelines. METHODS: The genotyping success rate was evaluated in 12 828 human immunodeficiency virus type 1 (HIV-1) plasma samples with viremia >50 copies/mL, tested using the commercial ViroSeq HIV-1 Genotyping System or a homemade system. Phylogenetic analysis was performed to test the reliability and reproducibility of the GRT at low-level viremia (LLV). Drug resistance was evaluated in 3895 samples from 2200 patients for whom treatment was unsuccessful (viremia >50 copies/mL) by considering the resistance mutations paneled in the 2013 International Antiviral Society list. RESULTS: Overall, the success rate of amplification/sequencing was 96.4%. Viremia levels of 50-200 and 201-500 copies/mL afforded success rates of 67.2% and 88.1%, respectively, reaching 93.2% at 501-1000 copies/mL and ≥97.3% above 1000 copies/mL. A high homology among sequences belonging to the same subject for 96.4% of patients analyzed was found. The overall resistance prevalence was 74%. Drug resistance was commonly found also at LLV. In particular, by stratifying for different viremia ranges, detection of resistance was as follows: 50-200 copies/mL = 52.8%; 201-500 = 70%; 501-1000 = 74%; 1001-10 000 = 86.1%; 10 001-100 000 = 76.7%; and >100 000 = 63% (P < .001). Similar bell-shaped results were found when the GRT analysis was restricted to 2008-2012, although at a slightly lower prevalence. CONCLUSIONS: In patients failing cART with LLV, HIV-1 genotyping provides reliable and reproducible results that are informative about emerging drug resistance.

Impact of pre-therapy viral load on virological response to modern first-line HAART.

BACKGROUND: We tested whether pre-HAART viraemia affects the achievement and maintenance of virological success in HIV-1-infected patients starting modern first-line therapies. METHODS: A total of 1,430 patients starting their first HAART (genotype-tailored) in 2008 (median; IQR: 2006-2009) were grouped according to levels of pre-HAART viraemia (≤ 30,000, 30,001-100,000, 100,001-300,000, 300,001-500,000 and > 500,000 copies/ml). The impact of pre-therapy viraemia on the time to virological success (viraemia ≤ 50 copies/ml) and on the time to virological rebound (first of two consecutive viraemia values > 50 copies/ml after virological success) were evaluated by Kaplan-Meier curves and Cox regression analyses. RESULTS: Median pre-HAART viraemia was 5.1 log10 copies/ml (IQR 4.5-5.5), and 53% of patients had viraemia > 100,000 copies/ml. By week 48, the prevalence of patients reaching virological success was > 90% in all pre-HAART viraemia ranges, with the only exception of range > 500,000 copies/ml (virological success = 83%; P < 0.001). Higher pre-HAART viraemia was tightly correlated with longer median time to achieve virological success. Cox multivariable estimates confirmed this result: patients with pre-HAART viraemia > 500,000 copies/ml showed the lowest hazard of virological undetectability after adjusting for age, gender, pre-HAART CD4+ T-cell count, transmitted drug resistance, calendar year and third drug administered (adjusted hazard ratio [95% CI]: 0.27 [0.21, 0.35]; P < 0.001). Pre-HAART viraemia > 500,000 copies/ml was also associated with higher probability of virological rebound compared with patients belonging to lower viraemia strata at weeks 4, 12 and 24 (P = 0.050). CONCLUSIONS: At the time of modern HAART, and even though an average > 90% of virological success, high pre-HAART viraemia remains an independent factor associated with delayed and decreased virological success. Patients starting HAART with > 500,000 copies/ml represent a significant population that may deserve special attention.

QTc interval prolongation in HIV-infected patients: a case-control study by 24-hour Holter ECG recording.

BACKGROUND: Aim of the study was to assess QTc interval by a 24-hour ECG recording in a group of HIV-infected individuals with a basal prolonged QTc. The risk factors associated with QTc prolongation and the indices of cardiovascular autonomic control were also evaluated. METHODS: A case-control study was performed using as cases 32 HIV-infected patients with prolonged (>440 msec) QTc interval as assessed by Holter ECG, and as controls 64 HIV-infected subjects with normal QTc interval. Autonomic function was evaluated by heart rate variability analysis during 24-hour recording. RESULTS: Duration of HIV disease was significantly longer among cases than among controls (p=0.04). Waist/hip ratio was also higher among cases than among controls (p=0.05). Frequency domain analysis showed the absence of physiologic decrease of low frequency (LF) in the night period in both cases and controls. The LF night in cases showed a statistically significant reduction when compared with controls (p=0.007). CONCLUSIONS: In our study group, QTc interval prolongation was associated with a longer duration of HIV infection and with a greater waist/hip ratio. HIV patients with QTc interval prolongation and with a longer duration of HIV infection were more likely to have an impairment of parasympathetic and sympathetic cardiac component.

Comparative analysis of drug resistance among B and the most prevalent non-B HIV type 1 subtypes (C, F, and CRF02_AG) in Italy.

In recent years, increasing numbers of patients infected with HIV-1 non-B subtypes have been treated with modern antiretroviral regimens. Therefore, a better knowledge of HIV drug resistance in non-B strains is crucial. Thus, we compared the mutational pathways involved in drug resistance among the most common non-B subtypes in Italy (F, C, and CRF02_AG) and the B subtype. In total, 2234 pol sequences from 1231 virologically failing patients from Central Italy were analyzed. The prevalence of resistance mutations in protease and reverse transcriptase between non-B and B subtypes has been evaluated. Among patients treated with nucleoside/nucleotide reverse transcriptase inhibitors (NRTI) and with thymidine analogues (TA) experience, TAMs1 M41L and L210W were less prevalent in CRF02_AG, while TAMs2 T215F and K219E were more prevalent in the F subtype. In NRTI-treated patients having experience with abacavir, didanosine, tenofovir, or stavudine the K65R mutation was mostly prevalent in the C subtype. In non-NRTI (NNRTI)-treated patients infected by the C subtype the prevalence of K103N was lower than in patients infected with other subtypes, while the prevalence of Y181C and Y188L was higher compared to subtype B. The prevalence of Y181C was higher also in subtype F as compared to subtype B. In patients treated with protease inhibitors, L89V was predominantly found in CRF02_AG, while the TPV resistance mutation T74P was predominantly found in the C subtype. Some differences in the genotypic drug resistance have been found among patients infected with B, C, F, and CRF02_AG subtypes in relationship to treatment. These results may be useful for the therapeutic management of individuals infected with HIV-1 non-B strains.

Consensus document on controversial issues in the diagnosis and treatment of bloodstream infections and endocarditis.

BACKGROUND: The treatment of severe bloodstream infections (sepsis, endocarditis, and infections of vascular prostheses) caused by Gram-positive microorganisms is made even more difficult by the emergence of resistant strains. The introduction of new antibiotics with activity against these strains has created new opportunities, but many controversial issues remain. CONTROVERSIAL ISSUES: The aim of this GISIG (Gruppo Italiano di Studio sulle Infezioni Gravi) working group - a panel of multidisciplinary experts - was to define recommendations for some controversial issues using an evidence-based and analytical approach. The controversial issues concerned the duration of therapy and role of aminoglycosides and teicoplanin in the treatment of Gram-positive bacterial endocarditis, the optimal use of the new antibiotics in the treatment of bloodstream infections caused by resistant Gram-positive strains, and the use of microbiological techniques (i.e., bactericidal serum testing and synergy testing) and of pharmacokinetic data (e.g., monitoring of plasma levels of antibiotics) in the treatment of difficult-to-treat Gram-positive bloodstream infections. METHODS: A systematic literature search of randomized controlled trials and/or non-randomized studies was performed mainly using the MEDLINE database. A matrix was created to extract evidence from original studies using the CONSORT method to evaluate randomized clinical trials and the Newcastle-Ottawa Quality Assessment Scale for non-randomized studies. The GRADE method for grading the quality of evidence and strength of recommendation was applied.

Historical resistance profile helps to predict salvage failure.

BACKGROUND: This study compared the predictive value for treatment failure of extended resistance detected in the current genotype resistance test (GRT) versus those from GRT history in patients with multiple combination antiretroviral therapy (cART) failures. METHODS: Patients who underwent three GRT between 1999 and 2007 were included. Extended resistance at genotypic sensitivity score (GSS) using the Rega 7.1 interpretation system compared with a non-standard definition (defined as class-wide resistance [CWR] on the basis of International AIDS Society-USA mutations) was assessed both for current and historical GRTs (a combination of mutations was detected in all three tests). The predictive role of extended resistance for treatment failure was evaluated with an adjusted Cox proportional hazard model. RESULTS: Overall, 177 patients were included. The historical GRT increased the number of patients with extended resistance to all three major drug classes by 25% in comparison with the current GRT. Using the GSS method, the absence of detection of any active drug in any drug class was predictive of failure with both the current and historical GRTs. Similarly, the number of active drugs in the cART regimen after the third resistance test, used as continuous variable, was also predictive of failure. Using both GSS approaches, current genotype had a higher effect than historical genotype on risk of treatment failure. Using the non-standard definition (CWR), historical resistance predicted failure better than current resistance. CONCLUSIONS: Our results provide an epidemiological demonstration that analysis of a combined latest and historical GRT, which also considers archived mutations, might better identify of the more virologically impaired patients in order to assess the best salvage treatment.

Role of hepatitis B virus, hepatitis D virus and other determinants on suppression of hepatitis C viraemia in HIV infected patients with chronic HCV infection: a longitudinal evaluation.

The role of hepatitis B virus (HBV) or hepatitis D virus (HDV) coinfections as determinants of hepatitis C virus (HCV) suppression in the setting of HIV-HCV coinfection are poorly understood. Our aim was to assess whether HCV viral replication may be affected by HBV or HDV coinfection in the setting of immunodeficiency driven by HIV.Among the 138 enrolled patients 28(20.3%) tested HCV RNA negative and 110 (79.7%) tested HCV RNA negative. The HCV RNA negative patients showed an higher rate of HBsAg positivity compared with those tested HCVRNA positive [12/28 (42.9%) and 5/110 (4.6%), respectively]. Patients with HCV-HBV-HDV coinfection had the highest chance of having an undetectable HCV RNA (adjusted odds ratio (AOR): 92.0, 95% confidence interval (CI) 5.7-1483.5, p<0.0001). Furthermore, HBV coinfection per se was also found to be independently associated with negative HCV viraemia (AOR: 18.5, 95% CI 2.4-143.5, p<0.0001). HBsAg-positive patients with negative HCV viraemia maintained undetectable levels over time. Our results support a direct role of HBV and HDV coinfections in suppressing HCV viraemia in HIV infected patients. This effect is durable over time, and is not influenced by HAART including anti-HBV drugs.

Self-reported sexual dysfunction is frequent among HIV-infected persons and is associated with suboptimal adherence to antiretrovirals.

Increased occurrence of sexual dysfunction (SD) among patients treated with highly active antiretroviral therapy (HAART) has been reported. To assess prevalence of self-reported SD and to identify factors related to this alteration with special focus to its relationship with adherence behavior, we conducted an intercohort analysis among HIV-infected persons treated with HAART. In an anonymous questionnaire investigating HAART nonadherence, patients were asked to report the occurrence of dysfunction in sexual activity over the previous 4 weeks. Among 612 participants, 125 (21%) reported some degree of SD. "Moderate"/"severe" alterations were reported in 6% and were independently associated with self-reported worsening of viro-immunological parameters (OR 3.90; 95% CI 1.08-14.18), higher symptom score (OR 1.13; 95% CI 1.05-1.22), and reporting abnormal fat accumulation (OR 4.33; 95% CI 1.55-12.11). Furthermore, nonadherent persons had an increased risk of SD (OR 3.44; 95% CI 1.30-9.08). In conclusion, patients' perceived SD represents a relevant problem for HIV-infected persons treated with antiretrovirals and is strongly associated with suboptimal HAART adherence.

gp41 sequence variability in HIV type 1 non-B subtypes infected patients undergoing enfuvirtide pressure.

Enfuvirtide is the first of a new class of antiretroviral drugs that inhibits HIV entry. It is a 36 amino acid synthetic peptide that mimics the HR2 region of the HIV-1 gp41, preventing the fusion of viral and cellular membranes. Up to now, enfuvirtide was designed based on the HIV-1 B-subtype gp41, and resistance mutations to the fusion inhibitor have been investigated primarily in individuals infected with this subtype. To fill the gap, we analyzed the full length gp41 protein sequence of HIV-1 non-B strains from individuals receiving enfuvirtide-containing regimens. No primary resistance to the enfuvirtide binding domain (36-45 residues) was found. Resistance mutations were detected at follow-up visits and were comparable to those described among B-subtype HIV-1-infected patients; no sequence changes were detected in crucial HR1/HR2 gp41 sites such as the cytotoxic T lymphocyte epitope, cysteine loop, ectodomain, and 5-helix interaction and binding region.