Mortality in KPC-producing Klebsiella pneumoniae bloodstream infections: a changing landscape

OBJECTIVES

To assess the impact of carbapenem resistance on mortality in Klebsiella pneumoniae bloodstream infection (BSI) in the era of novel β-lactam/β-lactamase inhibitor combinations.

MATERIAL AND METHODS

Retrospective study of patients with K. pneumoniae BSI between January and August 2020 in 16 centres (CARBANEW study within the MULTI-SITA project).

RESULTS

Overall, 426 patients were included: 107/426 (25%) had carbapenem-resistant K. pneumoniae (CR-Kp) BSI and 319/426 (75%) had carbapenem-susceptible K. pneumoniae (CS-Kp) BSI. Crude cumulative 30 day mortality was 33.8% and 20.7% in patients with, respectively, CR-Kp BSI and CS-Kp BSI (P = 0.027). Carbapenemase production or carbapenemase-encoding genes were detected in 84/98 tested CR-Kp isolates (85.7%), mainly KPC (78/84; 92.9%). Ceftazidime/avibactam was the most frequently used appropriate therapy for CR-Kp BSI (80/107; 74.7%). In multivariable analyses, variables showing an unfavourable association with mortality after correction for multiple testing were age-adjusted Charlson comorbidity index (HR 1.20; 95% CI 1.10-1.31, P < 0.001) and Pitt score (HR 1.33; 95% CI 1.15-1.55, P < 0.001), but not carbapenem resistance (HR 1.28, 95% CI 0.74-2.22, P = 0.410). In a propensity score-matched analysis, there was no difference in mortality between patients appropriately treated with ceftazidime/avibactam for CR-Kp BSI and patients appropriately treated with other agents (mainly meropenem monotherapy or piperacillin/tazobactam monotherapy) for CS-Kp BSI (HR 1.07; 95% CI 0.50-2.29, P = 0.866).

CONCLUSIONS

Our results suggest that the increased mortality in CR-Kp BSI compared with CS-Kp BSI is not (or no longer) dependent on the type of therapy in areas where ceftazidime/avibactam-susceptible KPC-producing isolates are the most prevalent type of CR-Kp.

Epidemiology and Microbiology of Skin and Soft Tissue Infections: Preliminary Results of a National Registry

Skin and soft tissue infections (SSTIs) represent a wide range of clinical conditions characterized by a considerable variety of clinical presentations and severity. Their aetiology can also vary, with numerous possible causative pathogens. While other authors previously published analyses on several types of SSTI and on restricted types of patients, we conducted a large nationwide surveillance programme on behalf of the Italian Society of Infectious and Tropical Diseases to assess the clinical and microbiological characteristics of the whole SSTI spectrum, from mild to severe life-threatening infections, in both inpatients and outpatients. Twenty-five Infectious Diseases (ID) Centres throughout Italy collected prospectively data concerning both the clinical and microbiological diagnosis of patients affected by SSTIs via an electronic case report form. All the cases included in our database, independently from their severity, have been managed by ID specialists joining the study while SSTIs from other wards/clinics have been excluded from this analysis. Here, we report the preliminary results of our study, referring to a 12-month period (October 2016-September 2017). During this period, the study population included 254 adult patients and a total of 291 SSTI diagnoses were posed, with 36 patients presenting more than one SSTIs. The type of infection diagnosed, the aetiological micro-organisms involved and some notes on their antimicrobial susceptibilities were collected and are reported herein. The enrichment of our registry is ongoing, but these preliminary results suggest that further analysis could soon provide useful information to better understand the national epidemiologic data and the current clinical management of SSTIs in Italy.

Usefulness of suPAR in the risk stratification of patients with sepsis admitted to the emergency department

To investigate the role of suPAR in patients with sepsis admitted to the Emergency Department (ED). We performed multicentre prospective trial including patients admitted to the ED of three different Italian hospitals. Patients were studied upon admission on day 1, 2, 4 and 7. They were subdivided into two groups: sepsis (group 1) and severe sepsis or septic shock (group 2). The two groups were comparable for age, gender and CRP level on day 1. Patients with severe sepsis or septic shock displayed significantly higher baseline levels of suPAR, PCT and lactate. In both groups, suPAR decreased across the time (p < 0.0005). Group 1 was not different from group 2 (p = 0.545) in mortality at 7 days, while group 2 had higher mortality at 30 days than group 1 (p = 0.022). At the multivariate analysis, lactate1 (p = 0.012) and age (p = 0.019) were independent predictors of mortality at 7 days, whereas suPAR1 (p = 0.023) and age (p = 0.032) were independent predictors of mortality at 30 days. Lactate and suPAR resulted the most predictive biomarkers in the risk stratification of patients with suspected infection initially admitted to the ED, according to their role in predicting 7- and 30-day mortality, respectively.

Burden of non-AIDS-defining and non-virus-related cancers among HIV-infected patients in the combined antiretroviral therapy era

The risk of cancer is substantially increased in HIV-infected patients. However, little is known about non-AIDS-defining cancers (NADCs) without an infectious etiology. A total of 5,090 HIV-infected patients registered in the Local Health Authority (LHA) of Brescia and receiving primary care at our clinic were included in a retrospective (1999-2009) analysis. The cancer diagnoses were obtained through a record-linkage procedure between our database and the LHA general database and population-based Cancer Registry of LHA. We compared risks of these malignancies with those of the general population living in the same health area by using age-standardized incidence ratios (SIRs). Poisson regression analysis was used to assess factors associated with non-virus-related NADCs. We recorded an increase in the SIR of non-virus-related NADCs over time, with 138 cancers diagnosed in 131 patients. The mean incidence rate was 42.6/10,000 person years and the median age at the diagnosis was 49 (range, 28-78) years old. Stratifying for gender, only HIV-infected males had an increased risk of non-virus-related NADCs [SIR=1.86; 95% confidence interval (CI), 1.55-2.26]. Risk was higher for lung (SIR=3.59; 95% CI, 2.36-5.45) and testis cancer (SIR=3.11; 95% CI, 1.48-6.52). However,, cancers of the prostate and breast in HIV-positive men and women were null (SIR=1.10; 95% CI, 0.53-2.32 and SIR=0.91; 95% CI, 0.47-1.74, respectively). The only predictors of non-virus-related NADCs included older age [incidence rate ratio (IRR)=1.10; 95% CI, 1.08-1.12 per each additional year, p<0.001] and a shorter or no exposition to combined antiretroviral therapy (cART) (IRR=2.31; 95% CI, 1.38-3.89, p=0.002). A CD4⁺ count lower than 50/mm³ was significantly associated with cancers only in the univariate model (IRR=1.40; 95% CI, 0.99-1.98, p=0.057). HIV-infected men showed a 2-fold increased risk of non-virus-related NADCs compared to the general population. However, the use of cART appeared to be beneficial in protecting against the development of these malignancies.

Clinical characteristics, incidence, and risk factors of HIV-related Hodgkin lymphoma in the era of combination antiretroviral therapy

HIV-infected patients are at increased risk for developing HIV-related Hodgkin lymphoma (HIV-HL) despite the success of combination antiretroviral therapy (cART). To study the incidence of HIV-HL in HIV-patients with respect to the general population of Brescia, Italy, we conducted a single-center cohort study of HIV-patients followed from 1999 to 2009. The incidence of HIV-HL was compared to the incidence in the general population of Brescia using standardized incidence ratios (SIRs). Poisson analysis was used to study the association between covariates and HL. A total of 5085 HIV-patients were observed among 30,946 person-years; 30 patients developed HIV-HL. The incidence rate was 9.9 (95% confidence interval [CI], 6.7-14.1) per 10,000 person-years of follow-up. HL was substantially more frequent in HIV-patients than in the general population living in the same district area [standardized incidence rate, SIR=21.8 (95% CI, 15.33-31)]. The risk of HIV-HL tended to increase with lowering CD4+ cell counts at time of HL diagnosis [adjusted incidence relative risk (IRR) for CD4 cell count<50 cells/μL: 41.70, p<0.001]. HL risk had been elevated during the 6 months after combination antiretroviral therapy (cART) initiation (IRR: 26.65, p<0.001). Twenty-two HIV-HL cases were matched to 3280 controls. In the year preceding HIV-HL diagnosis the mean change in CD4+ cell counts between cases and controls was significantly different (-99 cells/μL for cases vs. +37 cells/μL for controls, p<0.0001). Compared with the general population, HIV-infected patients showed an increased risk for developing HL. The risk of HIV-HL increased significantly in the first months after cART initiation.

Incidence of AIDS-defining cancers and virus-related and non-virus-related non-AIDS-defining cancers among HIV-infected patients compared with the general population in a large health district of Northern Italy, 1999-2009

OBJECTIVES

The aim of the study was to investigate the incidence of AIDS-defining cancers (ADCs) and virus-related and non-virus-related non-AIDS-defining cancers (NADCs) in HIV-infected patients compared with the general population, and to assess the risk factors associated with these malignancies.

METHODS

We performed a retrospective cohort study for the period from 1999 to 2009 of HIV-infected patients residing in the Local Health Authority of Brescia (northern Italy). Observed cancers in patients with HIV infection were compared with expected cancers in the population living in the same area using standardized incidence ratios (SIRs). Risk factors were assessed using Poisson regression analysis.

RESULTS

A total of 5090 HIV-infected patients were included in the study, with 32 390 person-years of follow-up. We recorded 416 tumours in 390 HIV-infected patients. Two hundred of these (48.1%) were ADCs, 138 (33.2%) were non-virus-related NADCs and 78 (18.7%) were virus-related NADCs. An increased risk (SIR = 4.2) of cancers overall was found in HIV-infected patients. A large excess of ADCs (SIR = 31.0) and virus-related NADCs (SIR = 12.3) was observed in HIV-infected patients, while the excess risk for non-virus-related NADCs was small (SIR = 1.6). The highest SIRs were observed for Kaposi sarcoma among ADCs and for Hodgkin lymphoma among virus-related NADCs. Conversely, among non-virus-related NADCs, SIRs for a broad range of malignancies were close to unity. In multivariate analysis, increasing age and CD4 cell count < 50 cells/μL were the only factors independently associated with all cancers.

CONCLUSIONS

Among HIV-infected people there was an excess of ADCs and also of NADCs, particularly those related to viral infections. Ageing and severe immunodeficiency were the strongest predictors.

[A population-based database to study malignancies in HIV-infected patients in the Local Health Unit of Brescia (Northern Italy), period 1999-2009]

OBJECTIVE

to complete the database of all patients infected by the human immunodeficiency virus (HIV) who lives in the area belonging to the Local Health Unit (ASL) of Brescia, Northern Italy,with all the cancers diagnosed in the period 1999-2009.

DESIGN

diagnoses of cancer between 1999 and 2009 registered in the electronic database in use in the Clinic of Infectious and Tropical Diseases (source A) for the clinic follow-up of HIV-infected patients were checked. Then, the cases were integrated with the data recorded in the ASL database (source B) and in the Cancer Registry of Brescia (source C).

SETTING AND PARTICIPANTS

all HIV-infected patients belonging to the ASL of Brescia followed-up in the Clinic of Infectious and Tropical Diseases of Brescia.

MAIN OUTCOME MEASURES

in the database were included all HIV-positive patients who had a diagnosis of cancer between 1999 and 2009. The diagnosis of cancer had to be present at least in two of the three sources considered; if it was recorded only in one of them, the source had to be an histological document or confirmed directly by the patient him/herself.

RESULTS

from the sourceA, 339 diagnoses of cancer were recorded, then other 82 records from the sources B and C were added, achieving a total of 421 cancers, belonging to 391 different patients. Half of the diagnoses was present in all the three sources considered. Among the AIDS-defining cancers (No. 200; 47.5%), Kaposi's sarcoma and non-Hodgkin lymphoma were the most frequent diagnosed tumours (22.8% and 22.33%, respectively). Among the non-AIDS-defining cancers (No. 221; 52.5%), malignancies of the skin other than melanoma (No. 41; 9.74%), tumours of the liver (No. 34; 8.08%) and Hodgkin lymphoma (No. 31; 7.36%) were the most frequent tumours.

CONCLUSIONS

the database of all HIVpositive patients, including the diagnoses of cancer between 1999 and 2009, represents an important instrument, not only for the clinical practice: collecting clinical and sociodemographics characteristics of these patients, it would be possible to perform clinical and epidemiological studies.

Increase in standard cholesterol and large HDL particle subclasses in antiretroviral-naïve patients prescribed efavirenz compared to atazanavir/ritonavir

BACKGROUND

Cardiovascular risk in HIV-infected patients is related, at least in part, to serum lipid alterations before and after HAART. Lipoprotein-particle subclasses may also have an effect, but comparative data after standard HAART regimens are limited.

METHODS

This was a substudy of a trial in 91 antiretroviral-naïve patients randomized to tenofovir + emtricitabine + atazanavir/ritonavir (ATV/r) or efavirenz (EFV). Over-time trends from baseline to week 48 in total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), HDL particles (HDLp), and TC:HDL-C and TG:HDL-C ratios were analyzed by analysis of covariance (ANCOVA). Furthermore, confidence intervals for differences between the 2 groups at week 48 were calculated. Indications for lipid-lowering interventions and low HDL-C were also studied.

RESULTS

ANCOVA showed that, with respect to patients receiving ATV/r, those prescribed efavirenz (EFV) had greater increases reported as mean differences in lipid values at week 48: 14 mg/dL (95% CI, 0.2 to 27) for TC, 14 mg/dL (95% CI, 4 to 25) for LDL-C, 5 mg/dL (95% CI, 2 to 9) for HDL-C, and 2.2 mg/dL (95% CI, 0.4 to 4) for large HDLp. Proportions of subjects with indications for lipid-lowering interventions and with HDL-C <40 mg/dL did not differ significantly.

CONCLUSIONS

Patients prescribed EFV had greater increases in TC, LDL-C, and HDL-C. Although no significant differences were detected between the 2 groups for the TC:HDL ratio and for indications to start lipid-lowering interventions, large HDLp increased more in the EFV group compared to the ATV/r group, suggesting a protective effect associated with EFV use.

Male breast cancer in an HIV-infected patient: a case report

Male breast cancer is rare and few cases of breast cancer in human immunodeficiency virus (HIV)-infected patients are reported. We describe the case of breast cancer in a 65-year-old HIV-positive man who presented a nodule near the nipple of his left breast. He did not report risk factors for breast cancer, but he had liver cirrhosis. Biopsy of the lesion revealed a ductal carcinoma and he was submitted to mastectomy and axillary dissection. Staging resulted in pT1c/pN1a/M0; it was positive for the presence of oestrogen/progesterone receptors, negative for the human epidermal growth factor receptor-22. He was also treated with local radiotherapy and tamoxifen. At cancer diagnosis, he received highly active antiretroviral therapy (HAART) with undetectable HIV viral load, and his CD4+ T-cell count was 445 cells/mm(3). Patients with HIV infection have a higher cancer risk due to immunosuppression: it concerns not only malignancies related to human acquired immunodeficiency syndrome (AIDS), but also other cancers. A heightened awareness of male breast cancer by HIV specialists is needed, especially for particular risk categories, such as trans-sexuals who take oestrogen therapies, and for the presence of breast conditions, such as gynecomastia, usually considered as part of the lipodystrophy syndrome.

Lung cancer in HIV-infected patients: the experience in Brescia from 1999 to 2009

Lung cancer (LC) is the most common cancer among the non AIDS-defining malignancies in the highly active antiretroviral therapy (HAART) era. We described 23 HIV infected patients with a LC diagnosis followed in the Clinic of Tropical and Infectious Diseases of Brescia during the period of 1999–2009. All of these patients except two ( n = 21, 91.3%) were cigarette smokers and all had at least one risk factor for developing cancer of the lung, or predisposing comorbidities, such as a COPD (chronic obstructive pulmonary disease) or a previous pneumonia. The median age at LC diagnosis was 53.6 years (range 21.2–71.4 years). Adenocarcinoma and squamous cell carcinoma were diagnosed in 10 cases (43.5%) respectively. In 21 subjects (91.3%) cancer was detected at stage IV with metastases. The median survival was 5.95 months. Greater intervention focused on the cessation of smoking is necessary, as well as the implementation of closer screening policies, especially in HIV-positive subjects with LC risk factors.

Lopinavir pharmacokinetic profiles in HIV-infected patients during rifabutin-based anti-mycobacterial therapy

OBJECTIVES

To evaluate the pharmacokinetic profile of ritonavir-boosted lopinavir in HIV-infected patients during rifabutin-based anti-mycobacterial therapy.

PATIENTS AND METHODS

A longitudinal, cross-over pharmacokinetic evaluation of lopinavir with and without rifabutin in HIV-infected subjects with mycobacterial disease was done. All received lopinavir/ritonavir (400/100 mg twice a day) + an adjusted rifabutin dose of 150 mg every other day. Twelve-hour lopinavir pharmacokinetic sampling occurred at 2 weeks (T1) and 6 weeks (T2) after starting combined therapy and 10 weeks after completion of adjusted rifabutin (T3). Plasma was assayed using an HPLC method; lopinavir plasma concentration-time data were analysed using non-compartmental methods.

RESULTS

In 10 patients with complete lopinavir curves at T1, T2 and T3 pharmacokinetic values were, respectively: AUC(0-12), 187.5, 161.8 and 121.1 μg · h/mL; C(trough), 13.2, 10.0 and 7.7 μg/mL; C(max), 18.7, 15.9 and 13.3 μg/mL; and apparent oral clearance (CL/F), 0.035, 0.037 and 0.045 L/h/kg. Lopinavir C(trough) and AUC(0-12) were significantly higher at T1 compared with T3 while CL/F remained unchanged throughout. Combined treatment was well tolerated and none of the patients experienced moderate to severe lopinavir-related adverse events.

CONCLUSIONS

Lopinavir serum concentrations are not reduced when the drug is administered together with an adjusted dose of 150 mg of rifabutin every other day.

Prospective evaluation of bone markers, parathormone and 1,25-(OH)₂ vitamin D in HIV-positive patients after the initiation of tenofovir/emtricitabine with atazanavir/ritonavir or efavirenz

BACKGROUND

Increased risk of fractures and osteoporosis have been associated with the use of antiretroviral drugs. There is a paucity of prospective evaluations of bone markers after the initiation of drugs currently recommended to treat HIV infection and results on the evolution of these markers are conflicting. Lastly, the effect of tenofovir on 1,25-(OH)₂ vitamin D is uncertain.

METHODS

We performed a prospective study on the evolution of bone markers, parathormone and 1,25-(OH)₂ vitamin D before and after standard antiretroviral regimens. This was a sub-study of a trial conducted in antiretroviral-naïve patients randomized to tenofovir + emtricitabine in combination with either atazanavir/ritonavir (ATV/r) or efavirenz (EFV). Follow-up lasted 48 weeks. The following bone markers were analyzed: C-terminal cross-laps (CTx), osteocalcin (OC), osteoprotegerin (OPG), and receptor activator of nuclear factor κB ligand (RANKL). Mixed-factorial analysis of variance with random-coefficient general linear model was used to compare their trends over time and linear multivariable regression was performed with a backward selection method to assess predictors of their variations from baseline to week 48. Trends of parathormone and 1,25-(OH)₂ vitamin D were also evaluated.

RESULTS

Seventy-five patients were studied: 33 received EFV and 42 ATV/r. Significant increases were found for all markers except for RANKL. There was a significant direct association between CTx and OC increases. Multivariable analysis showed that higher glomerular filtration rate (estimated through cystatin C clearance) predicted greater OPG increase, while older age, higher HIV RNA at baseline and use of ATV/r predicted greater CTx increase. A significant increase of parathormone accompanied the evolution of the study markers. 1,25-(OH)₂ vitamin D remained stable, though a seasonality variation was demonstrated.

CONCLUSIONS

These data demonstrate CTx increase (bone resorption marker) corresponding to OC increase (bone formation marker) early upon HAART initiation. Moreover, predictors of bone marker increases have been suggested, possibly indicating that a stricter monitoring of bone health and pro-active interventions are needed in older patients, those with higher HIV RNA, prescribed ATV/r rather than EFV, and with decreased renal function at baseline. Further studies are needed to clarify the mechanisms responsible for up-regulation of bone turnover markers, as well as to understand if and what markers are best correlated or predictive of pathological fractures.

A randomized, pilot trial to evaluate glomerular filtration rate by creatinine or cystatin C in naive HIV-infected patients after tenofovir/emtricitabine in combination with atazanavir/ritonavir or efavirenz

BACKGROUND

Glomerular filtration rate (GFR) estimated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation based on creatinine or cystatine C may be more accurate methods especially in patients without chronic kidney disease. There is lack of data on GFR estimated by these methods in patients on highly active antiretroviral therapy.

METHODS

Antiretroviral-naive HIV-infected patients were randomized to tenofovir/emtricitabine in association with atazanavir/ritonavir (ATV/r) or efavirenz (EFV) Patients had to have an actual creatinine clearance >50 mL/minute (24-hour urine collection) and were followed for 48 weeks.

RESULTS

Ninety-one patients (48 ATV/r, 43 EFV) were recruited. Using the CKD-EPI creatinine formula, there was a significant decrease in GFR up to week 48 in patients receiving ATV/r (4.9 mL/minute/m(2), P = 0.02) compared with a not statistically significant increment in patients prescribed EFV. Using the cystatin C-based equation, we found greater decrease in GFR in both arms, although, in the EFV arm, the decrease was not statistically significant (5.8 mL/minute/m(2), P = 0.92). At multivariable analysis, ATV/r was a significant predictor of greater decrease in estimated glomerular filtration rate (eGFR) (P = 0.0046) only with CKD-EPI creatinine.

CONCLUSIONS

ATV/r plus tenofovir caused greater GFR decreases compared with EFV. The evaluation of eGFR by cystatin C confirmed this result, but this method seemed to be more stringent, probably precluding the possibility to detect a significant difference in the pattern of eGFR evolution between the two arms over time. More studies are needed to understand the clinical relevance of these alterations and whether cystatin C is a more appropriate method for monitoring GFR in clinical practice.

Prevalence and Risk Factors for Etravirine Resistance among Patients Failing on Non-Nucleoside Reverse Transcriptase Inhibitors

Background

Prevalence and factors associated with etravirine (ETV) resistance mutations among patients failing on first-generation non-nucleoside reverse transcriptase inhibitors (NNRTI) merit investigation.

Methods

The study comprised an analysis of all sequential patients attending the Institute of Infectious Diseases (Brescia, northern Italy) who performed a genotypic resistance testing (GRT) after ≥3 months of a stable NNRTI-based regimen between 2001 and 2006. Multivariable ordinal logistic regression analysis was performed to assess predictors of ETV resistance mutations.

Results

Out of 248 strains, 153 (61.7%) harboured ≥1 ETV resistance mutations. In particular, 88 (35.5%), 53 (21.4%) and 12 (4.8%) harboured one, two and three mutations, respectively. The most frequent mutations were G190A (23%), Y181C (23%) and K101E (14.1%). Use of nevirapine (odds ratio [OR] 2.73; 95% confidence level [CI] 1.62–4.62; P<0.001) and a longer time frame between first HIV RNA >500 copies/ml and GRT (per month, OR 1.05; 95% CI 1.01–1.09; P=0.012) were associated with a greater number of ETV resistance mutations. Conversely, higher CD4+ T-cell counts at nadir (per 100 cells/mm3, OR 0.81; 95% CI 0.67–0.98; P=0.029) and use of lamivudine/emtricitabine (OR 0.57; 95% CI 0.37–0.87; P=0.009) were protective. Accumulation of ETV resistance-associated mutations was demonstrated by sequential GRT in 4/35 patients (all treated with nevirapine).

Conclusions

Mutations associated with ETV resistance were common among patients failing on NNRTI, but prevalence of viral strains harbouring three mutations was low. Use of efavirenz and co-administration of lamivudine reduced the risk of ETV resistance. The continued use of the current NNRTI in a failing regimen may select for additional resistant variants.

Evidence of Long-Term Suppression of Hepatitis B virus DNA by Tenofovir as Rescue Treatment in Patients Coinfected by HIV

Background

The efficacy of long-term hepatitis B virus (HBV) treatment with tenofovir (TDF) in relation to lamivudine (LMV) resistance in HIV patients failing on LMV deserves further investigations.

Methods

HIV–HBV coinfected patients were selected, provided that LMV was included in the first highly active antiretroviral therapy regimen and TDF was subsequently introduced.

Results

Forty HIV–HBV patients were included, 25 had undetectable HBV DNA on LMV and 15 were failing on LMV treatment. Three cases of triple 173V+180M+ 204V HBV reverse transcriptase (rt) mutants were identified, as well as several mutations or polymorphisms in the surface antigen gene at positions possibly correlating with vaccine escape. A new mutation (rtI233V) was found in one adefovir-naive patient. In 10 patients, uninterrupted TDF treatment led to a sustained treatment response for a median of 160 (interquartile range 111–189) weeks. Two patients underwent intermittent treatment with TDF and LMV, responding any time TDF was reintroduced. In one patient, TDF without LMV provided treatment response. One patient did not respond to TDF because of low treatment adherence. One patient infected with the triple rt mutant did not respond to entecavir, but TDF was successful as rescue.

Conclusions

Combination therapy with TDF was effective against HBV mutant viruses resistant to LMV and provided sustained control of HBV replication over long-term follow-up, even after entecavir failure. Moreover, suppression of HBV vaccine escape variants could provide important benefits from a public health perspective.

Evidence of long-term suppression of hepatitis B virus DNA by tenofovir as rescue treatment in patients coinfected by HIV

BACKGROUND

The efficacy of long-term hepatitis B virus (HBV) treatment with tenofovir (TDF) in relation to lamivudine (LMV) resistance in HIV patients failing on LMV deserves further investigations.

METHODS

HIV-HBV coinfected patients were selected, provided that LMV was included in the first highly active antiretroviral therapy regimen and TDF was subsequently introduced.

RESULTS

Forty HIV-HBV patients were included, 25 had undetectable HBV DNA on LMV and 15 were failing on LMV treatment. Three cases of triple 173V + 180M + 204V HBV reverse transcriptase (rt) mutants were identified, as well as several mutations or polymorphisms in the surface antigen gene at positions possibly correlating with vaccine escape. A new mutation (rtl233V) was found in one adefovir-naive patient. In 10 patients, uninterrupted TDF treatment led to a sustained treatment response for a median of 160 (interquartile range 111-189) weeks. Two patients underwent intermittent treatment with TDF and LMV, responding any time TDF was reintroduced. In one patient, TDF without LMV provided treatment response. One patient did not respond to TDF because of low treatment adherence. One patient infected with the triple rt mutant did not respond to entecavir, but TDF was successful as rescue.

CONCLUSIONS

Combination therapy with TDF was effective against HBV mutant viruses resistant to LMV and provided sustained control of HBV replication over long-term follow-up, even after entecavir failure. Moreover, suppression of HBV vaccine escape variants could provide important benefits from a public health perspective.

Prevalence and risk factors for etravirine resistance among patients failing on non-nucleoside reverse transcriptase inhibitors

BACKGROUND

Prevalence and factors associated with etravirine (EW) resistance mutations among patients failing on first-generation non-nucleoside reverse transcriptase inhibitors (NNRTI) merit investigation.

METHODS

The study comprised an analysis of all sequential patients attending the Institute of Infectious Diseases (Brescia, northern Italy) who performed a genotypic resistance testing (GRT) after > or =3 months of a stable NNRTI-based regimen between 2001 and 2006. Multivariable ordinal logistic regression analysis was performed to assess predictors of ETV resistance mutations.

RESULTS

Out of 248 strains, 153 (61.7%) harboured > or =1 ETV resistance mutations. In particular, 88 (35.5%), 53 (21.4%) and 12 (4.8%) harboured one, two and three mutations, respectively. The most frequent mutations were G190A (230%), Y181C (23%) and K101E (14.1%). Use of nevirapine (odds ratio [OR] 2.73; 95% confidence level [CI] 1.62-4.62; P<0.001) and a longer time frame between first HIV RNA >500 copies/ml and GRT (per month, OR 1.05; 95% CI 1.01-1.09; P=0.012) were associated with a greater number of ETV resistance mutations. Conversely, higher CD4+ T-cell counts at nadir (per 100 cells/mm3, OR 0.81; 95% CI 0.67-0.98; P=0.029) and use of lamivudine/emtricitabine (OR 0.57; 95% CI 0.37-0.87; P=0.009) were protective. Accumulation of ETV resistance-associated mutations was demonstrated by sequential GRT in 4/35 patients (all treated with nevirapine).

CONCLUSIONS

Mutations associated with ETW resistance were common among patients failing on NNRTI, but prevalence of viral strains harbouring three mutations was low. Use of efavirenz and co-administration of lamivudine reduced the risk of ETW resistance. The continued use of the current NNRTI in a failing regimen may select for additional resistant variants.

Drug-induced modulation of IL-2 production in experimental murine trypanosomiasis

In this study we evaluated the effects of N-acetyl-cysteine and indomethacin in restoring IL-2 producing ability in vitro of splenocytes from mice infected with Trypanosoma equiperdum. Spleen cells from these mice were found to produce significantly lower levels of interleukin-2 (IL-2) in response to mitogen stimulation than spleen cells from uninfected control mice. This was accompanied by considerable suppression of IL-2-receptor expression, which was not attributable to the elimination of a particular T-cell subset. Impairment of IL-2 production was not due to a primary defect in L3T4+ T-cells, but rather to the presence of both adherent and non-adherent suppressor cells that apparently acted via prostaglandin-independent and dependent mechanisms. In fact, the IL-2-producing ability of lymphocytes from infected mice could be efficiently restored by in vitro exposure to N-acetyl-cysteine or indomethacin.

Involvement of the Th1 subset of CD4+ T cells in acquired immunity to mouse infection with Trypanosoma equiperdum

Heat- or merthiolate-inactivated Trypanosoma equiperdum was administered to recipient mice that were subsequently challenged with viable inocula of the same stabilate. Only mice inoculated with merthiolate-killed parasites were completely protected from a challenge inoculum of 10(3) trypanosomes, an effect that was abolished by prior immunosuppression of mice. Immune sera from protected animals contained high levels of interferon (IFN)-gamma and specific IgG2a antibodies. Spleen cells from these mice produced high amounts of interleukin (IL)-2 and IFN-gamma in vitro in response to specific antigen or concanavalin A, whereas splenocytes from mice receiving heat-killed parasites produced high amounts of IL-6. In contrast, the production of tumor necrosis factor (TNF)-alpha and colony-stimulating activity (CSA) was not significantly different in mice receiving either killed parasite preparation. The protection in immunized mice was associated with the detection of strong delayed-type hypersensitivity (DTH) to T. equiperdum antigens, an effect that could be adoptively transferred onto naive recipients by specifically immune CD4+ lymphocytes. These results suggest that the development of protective immunity in mice to T. equiperdum by our immunization protocol may involve the activity of helper/DTH T cells, particularly those of the Th1 subset.