DECLINE OF PREVALENCE OF RESISTANCE ASSOCIATED SUBSTITUTIONS TO NS3 AND NS5A INHIBITORS AT DAA- FAILURE IN HEPATITIS C VIRUS IN ITALY OVER THE YEARS 2015 TO 2018

Background: A minority of patients fails to eliminate HCV and resistance-associated substitutions (RASs) are commonly detected at failure of interferon-free DAA regimens . Methods: Within the Italian network VIRONET-C, the prevalence of NS3/NS5A/NS5B RASs was retrospectively evaluated in patients who failed an EASL recommended DAA-regimen in 2015-2018 . The geno2pheno system and Sorbo MC et al. Drug Resistance Updates 2018 were used to infer HCV- genotype/subtype and predict drug resistance . The changes in prevalence of RASs over time were evaluated by chi-square test for trend, predictors of RASs at failure were analysed by logistic regression . Results: We included 386 HCV infected patients: 75% males, median age was 56 years (IQR 52-61), metavir fibrosis stage F4 in 76%; 106 (28%) were treatment- experienced: 91 (86%) with IFN-based treatments, 26 (25%) with DAAs. Patients with HIV and HBV coinfection were 10% (33/317) and 8% (6/72), respectively. HCV genotype was 1b in 122 pts (32%), 3 in 109 (28%), 1a in 97 (25%), 4 in 37 (10%), 2 in 21 (5%). DAA regimens were: LDV/SOF in 115 (30%), DCV/SOF in 103 (27%), 3D in 83 (21%), EBR/GRZ in 32 (8%), VEL/SOF in 29 (7%), GLE/PIB in 18 (5%) and 2D in 6 (2%); ribavirin was administered in 123 (32%) . The NS5A fasta-sequence was available for all patients, NS5B for 361 (94%), NS3 for 365 (95%) . According to the DAA failed the prevalence of any RASs was 90%, namely 80/135 (59%) in NS3, 313/359 (87%) in NS5A, 114/286 (40%) in NS5B . The prevalence of any RASs significantly declined from 2015 to 2018 (93% vs 70%, p=0.004): NS5A RASs from 90% to 72% (p=0 .29), NS3 RASs from 74% to 18% (p<0 .001), while NS5B RASs remained stable . Independent predictors of any RASs included advanced fibrosis (AOR 6.1, CI 95% 1.8-20.3, p=0 .004) and genotype (G2 vs G1a AOR 0 .03, CI 95% 0 .002- 0 .31, p=0 .004; G3 vs G1a AOR 0 .08, CI 95% 0 .01-0 .62, p=0 .02; G4 vs G1a AOR 0 .05, CI 95% 0 .006-0 .46, p=0 .008), after adjusting for age, previous HCV treatment and year of genotype . Notably, full activity was predicted for GLE/PIB in 75% of cases and for at least two components of VEL/SOF/VOX in 53% of cases, no case with full-resistance to either regimen was found . Conclusion: Despite decreasing prevalence over the years, RASs remain common at virological failure of DAA treatment, particularly in patients with the highest grade of liver fibrosis. The identification of RASs after failure could play a crucial role in optimizing retreatment strategies

Traditional Cultures versus Next Generation Sequencing for Suspected Orthopedic Infection: Experience Gained from a Reference Centre

(Background) The diagnosis and the antimicrobial treatment of orthopedic infection are challenging, especially in cases with culture-negative results. New molecular methods, such as next-generation sequencing (NGS), promise to overcome some limitations of the standard culture, such as the detection of difficult-to-grow bacteria. However, data are scarce regarding the impact of molecular techniques in real-life scenarios. (Methods) We included cases of suspected orthopedic infection treated with surgery from May 2021 to September 2023. We combined traditional cultures with NGS. For NGS, we performed a metagenomic analysis of ribosomal 16s, and we queried dedicated taxonomic libraries to identify the species. To avoid false positive results, we set a cut-off of 1000 counts of the percentage of frequency of reads. (Results) We included 49 patients in our study. Our results show the presence of bacteria in 36/49 (73%) and 29/49 (59%) cases studied with NGS and traditional cultures, respectively. The concordance rate was 61%. Among the 19/49 discordant cases, in 11/19 cases, cultures were negative and NGS positive; in 4/19, cultures were positive and NGS negative; and in the remaining 4/19, different species were detected by traditional cultures and NGS. (Conclusions) Difficult-to-grow microorganisms, such as slow-growing anaerobic bacteria, were better detected by NGS compared to traditional culture in our study. However, more data to distinguish between true pathogens and contaminants are needed. NGS can be an additional tool to be used for the diagnosis of orthopedic infections and the choice of appropriate antimicrobial therapy

Tenofovir renal safety in HIV-infected patients: results from the SCOLTA project

Objective: To evaluate the prevalence and incidence of nephrotoxicity in HIV-infected patients enrolled in the SCOLTA Project tenofovir cohort and to identify possible risk factors. Design: The SCOLTA Project is a prospective, observational, multicenter study involving 25 infectious disease departments in Italy created to assess the incidence of severe adverse events in patients receiving new antiretroviral drugs. Patients: The SCOLTA Project tenofovir cohort includes a total of 754 HIV infected patients. Results: Data including grade IIeIV creatinine elevations according to ACTG scale were available in 354 patients, 237 (67%) males with a mean age of 40.1 ± 7.6 years enrolled in the SCOLTA Project tenofovir cohort. During a mean follow up of 19.5 ± 11.5 months creatinine elevations were reported in 9/354 (2.5%) patients, all males. Mean duration of tenofovir therapy at the event was 9.5 ± 5 months. The overall incidence was 1.6 (95% CI 1.5e1.7) per 100 person-years (p-y) and 0.5 (95% CI 0.4e0.6) p-y for grade III. No grade IV creatinine elevations were reported. Patients with nephrotoxicity were older and more frequently male, HCV infected, in CDC stage C and their CD4 cell count was significantly lower than those without nephrotoxicity. No significant difference was found between tenofovir co-administered antiretroviral drugs. Conclusions: Both prevalence and incidence of nephrotoxicity were low in patients receiving tenofovir in a non-selected clinical setting. Renal injury in patients receiving tenofovir seems associated with the presence of co-morbidities and with advanced HIV infection

Box-plot of Tenofovir (TDF) plasma trough concentrations measured in 100 HIV-infected patients.

<p>Box-plot of Tenofovir (TDF) plasma trough concentrations measured in 100 HIV-infected patients.</p

Main demographic, haematological and biochemical parameters of HIV-positive patients given tenofovir as part of their maintenance antiretroviral therapy (data were given as mean ± standard deviation).

<p>Main demographic, haematological and biochemical parameters of HIV-positive patients given tenofovir as part of their maintenance antiretroviral therapy (data were given as mean ± standard deviation).</p

Comparison of demographic, haematological and biochemical parameters of HIV-positive patients that did (n = 26) or did not (n = 74) develop tenofovir-related adverse events (data were given as mean ± standard deviation).

*<p>chi square test.</p

TDF plasma trough concentrations measured female (panel A) and male (panel B) HIV infected patients stratified according to median body weight (**p<0.01).

<p>TDF plasma trough concentrations measured female (panel A) and male (panel B) HIV infected patients stratified according to median body weight (**p<0.01).</p

Distribution of atazanavir (ATV) plasma trough concentrations according to daily drug dosage.

<p>*given either as 400 mg qd or 200 mg bid; IQR: interquartile range</p><p>Distribution of atazanavir (ATV) plasma trough concentrations according to daily drug dosage.</p