Sequential or Combination Treatments as Rescue Therapies in Immunocompromised Patients with Persistent SARS-CoV-2 Infection in the Omicron Era: A Case Series

Prolonged SARS-CoV-2 infections are widely described in immunosuppressed patients, but safe and effective treatment strategies are lacking. We aimed to outline our approach to treating persistent COVID-19 in patients with immunosuppression from different causes. In this case series, we retrospectively enrolled all immunosuppressed patients with persistent SARS-CoV-2 infections treated at our centers between March 2022 and February 2023. Patients received different sequential or combination regimens, including antivirals (remdesivir, nirmatrelvir/ritonavir, or molnupiravir) and/or monoclonal antibodies (mAbs) (tixagevimab/cilgavimab or sotrovimab). The main outcome was a complete virological response (negative SARS-CoV-2 RT-PCR on nasopharyngeal swabs) at the end of treatment. Fifteen patients were included as follows: eleven (11/15; 73%) with hematological disease and four (4/15; 27%) with recently diagnosed HIV/AIDS infection. Six patients (6/15; 40%) received a single antiviral course, four patients (4/15; 27%) received an antiviral and mAbs sequentially, and two patients (13%) received three lines of treatment (a sequence of three antivirals or two antivirals and mAbs). A combination of two antivirals or one antiviral plus mAbs was administered in three cases (3/15, 20%). One patient died while still positive for SARS-CoV-2, while fourteen (14/15; 93%) tested negative within 16 days after the end of treatment. The median time to negativization since the last treatment was 2.5 days. Both sequential and combination regimens used in this study demonstrated high efficacy and safety in the high-risk group of immunosuppressed patients.

Transient plasma viral rebound after SARS-CoV-2 vaccination in an exceptional HIV-1 elite controller woman

BACKGROUND

Elite controllers are able to control viral replication without antiretroviral therapy. Exceptional elite controllers do not show disease progression for more than 25 years. Different mechanisms have been proposed and several elements of both innate and adaptive immunity are implicated. Vaccines are immune stimulating agents that can promote HIV-RNA transcription; transient plasma HIV-RNA detectability has been described within 7-14 days after different vaccinations. The most reliable mechanism involved in virosuppressed people living with HIV is a generalized inflammatory response that activates bystander cells harboring latent HIV. So far no data about viral load increase in elite controllers after SARS-CoV-2 vaccination are reported in literature.

CASE PRESENTATION

We report the case of a 65-year-old woman of European ancestry, diagnosed with HIV-1/HCV co-infection more than 25 years ago. Since then, HIV-RNA remained undetectable and she never received ARV therapy. In 2021 she was vaccinated with mRNA-BNT162b2 vaccine (Pfizer-BioNTech®). She was administered with three doses in June, July and October 2021, respectively. The last available viral load was undetectable in March 2021. We observed an increase of VL at 32 cp/ml and 124 cp/mL, two and seven months after the second vaccine dose, respectively. During monthly follow-up, HIV-RNA gradually and spontaneously dropped becoming undetectable without ARV intervention. COVID-19 serology was positive with IgG 535 BAU/mL, showing response to vaccination. We measured total HIV-DNA at different time-points and we found it detectable both at the time of the higher plasma HIV-RNA (30 cp/10^6 PBMCs) and when it was undetectable (13 cp/10^6 PBMCs), in reduction.

CONCLUSIONS

This case is the first report, to our knowledge, describing a rebound of plasma HIV-RNA in an elite controller after three doses of mRNA-BNT162b2 vaccine for SARS-CoV-2. Concomitantly with a spontaneous reduction of plasma HIV-RNA ten months after the third dose of mRNA-BNT162b2 vaccine (Pfizer-BioNTech®) without antiretroviral therapy intervention, we observed a reduction of total HIV-DNA in peripheral mononuclear cells. The potential role of vaccinations in altering HIV reservoir, even in elite controllers when plasma HIV-RNA is undetectable, could be a valuable aspect to take into account for the future HIV eradication interventions.

Fast and reliable real life data on COVID-19 triaging with ID NOW

In the context of SARS-CoV-2 pandemic, rapid and easy-to-perform diagnostic methods are essential to limit the spread of the virus and for the clinical management of COVID-19 patients. Although real-time polymerase chain reaction remains the “gold standard” to diagnose acute infections, this technique is expensive, requires trained personnel, well-equipped laboratory and is time-consuming. A prospective evaluation of the Abbott ID NOW COVID-19 point-of-care testing that uses isothermal nucleic acid amplification for the qualitative detection of SARS-CoV-2 RdRp gene was run in the Emergency Department during the third wave of COVID-19 pandemic. ID-NOW significantly simplified SARS-CoV-2 identification and COVID-19 patient triaging, being highly valuable in rapidly locating febrile patients in or out of COVID-19 areas, and can be considered as a first-line diagnostic test in the Emergency Room setting.

SARS-CoV-2 microfluidic antigen point-of-care testing in Emergency Room patients during COVID-19 pandemic

In Emergency Room, Point-of-care antigen testing for SARS-CoV-2 antigen can expedite clinical strategies for patient management. We tested 1,232 consecutive patients during Italian second wave peak using the recent LumiraDx microfluidic assay. This assay showed high concordance (96.9 %), sensitivity and specificity compared to molecular testing, being highly valuable.

Urgent need of rapid tests for SARS CoV-2 antigen detection: Evaluation of the SD-Biosensor antigen test for SARS-CoV-2

At the time of writing, FIND has listed four CE-marked SARSCoV-2 antigen tests. We evaluated the recently CE-approved rapid POCT SD-Biosensor for SARS-CoV-2 nucleoprotein detection in nasopharyngeal secretions from 330 patients admitted to the Emergency Room for a suspect of COVID-19 and travelers returning home from high risk countries. Sensitivity, specificity, accuracy, negative and predictive values were consistent with the use of the test to mass-screening for SARS-CoV-2 surveillance.

HIV-1 detection in the olfactory mucosa of HIV-1-infected participants

OBJECTIVE

HIV infection chronically affects the central nervous system (CNS). Olfactory mucosa is a unique site in the respiratory tract that is directly connected to the CNS; thus we wanted to evaluate olfactory mucosa as a surrogate of CNS sampling.

DESIGN

We conducted a preliminary study examining HIV populations and susceptible cells in the olfactory mucosa.

METHODS

Olfactory mucosa was sampled by minimally invasive brushing. Cerebrospinal fluid (CSF) analyses were performed as per routine clinical procedures. Olfactory marker protein, CD4+, CD8+, and trans-activator of transcription (TAT) expressions were assessed by immunohistochemistry. Plasma, CSF, and olfactory mucosa HIV-RNA were quantified using the Cobas AmpliPrep/Cobas TaqMan assay, whereas HIV proviral DNA was evaluated on peripheral blood mononuclear cell and olfactory mucosa. HIV-1 env deep sequencing was performed for phylogenetic analysis.

RESULTS

Among ART-naive participants, 88.2% (15/17), and among ART-treated participants, 21.4% (6/28) had detectable HIV-RNA in samples from their olfactory mucosa; CSF escape was more common in patients with olfactory mucosa escape (50 vs. 7.9%; P = 0.010). Olfactory mucosa samples contained few cells positive for CD4, CD8, or HIV-DNA, and no HIV TAT-positive cells, indicating that this approach efficiently samples virions in the olfactory mucosa, but not HIV-infected cells. Yet, using a deep sequencing approach to phylogenetically compare partial HIV env genes in five untreated participants, we identified distinct viral lineages in the OM.

CONCLUSIONS

The results of this study suggest that nasal brushing is a well tolerated and useful technique for sampling the olfactory mucosa. HIV-RNA was detected in most naïve and in some treated patients, warranting larger longitudinal studies.

Evaluation of the performance of a new automated HIV combination assay

BACKGROUND

More and more countries test for HIV infection using combination assays that simultaneously detect p24 antigen and HIV antibodies.

OBJECTIVE

To assess the performance of a new HIV combo assay: LIAISON^® XL murex HIV Ab/Ag HT.

STUDY DESIGN

The assays were examined with a total of 3090 samples that included 769 selected HIV antibody-negative samples, 1849 unselected HIV samples, 15 HIV-1 p24 Ag reference samples, 90 primary HIV-1 infection (PHI) samples, 167 HIV-1 antibody-positive samples (well characterized of groups M and O), 95 HIV-1 antibody-positive samples and 105 HIV-2 antibody-positive samples.

RESULTS

The specificity of the LIAISON^® XL murex HIV Ab/Ag HT was 99.7%. The analytical sensitivity of Ag p24 of the LIAISON^® XL murex HIV Ab/Ag HT was 0.58IU/mL and 9.93pg/mL when using WHO and French national standards, respectively. All screened HIV subtypes was identified by this assay. Also, 90 PHI specimens were detected by this screening assay.

CONCLUSION

The sensitivity and specificity of the LIAISON^® XL murex HIV Ab/Ag HT assay are high. Hence the assay offers automated high-throughput screening with ability to detect primary infection.

Cerebrospinal fluid viral load and neopterin in HIV-positive patients with undetectable viraemia

BACKGROUND

Cerebrospinal fluid (CSF) HIV RNA is commonly used as a marker of compartmental antiviral activity in HIV-positive patients. Undetectable CSF HIV RNA levels have been associated with low CSF neopterin levels and better neurocognitive performances. The aim of this study was to analyse the prevalence and predictors of non-detectable CSF HIV RNA using a commercial assay.

METHODS

In adult HIV-positive HAART-treated patients with confirmed plasma HIV RNA <50 copies/ml, CSF HIV RNA (with Roche Amplicor Assay) and neopterin were measured.

RESULTS

112 adult patients were included. Plasma and CSF HIV RNA were non-detectable (target not detected [TND]) in 29 (25.9%) and 36 (32.1%) patients, respectively. CSF TND was observed more frequently in patients with plasma TND (P=0.005, OR=3.87). CSF neopterin levels were associated with age (rho =0.333, P=0.002) and current (rho= -0.272, P=0.015) and nadir (rho =-0.240, P=0.038) CD4⁺ T-lymphocytes; the lowest CSF neopterin concentration was observed in patients with CSF TND versus other viral load strata (0.62 mg/dl versus 0.78 mg/dl; P=0.048).

CONCLUSIONS

Efficaciously treated HIV-positive patients with detectable plasma HIV RNA might imperfectly control CSF viral replication. Prospective studies addressing the management and neurocognitive consequences of CSF low-level viraemia are warranted.

First external quality assurance program of the Italian HLA-B*57:01 Network assessing the performance of clinical virology laboratories in HLA-B*57:01 testing

BACKGROUND

Since the HLA-B*57:01 allele is strongly associated with abacavir hypersensitivity reaction, testing for the presence of HLA-B*57:01 is mandatory before administration of abacavir. While HLA-B*57:01 testing is usually provided by pharmacogenetics, genetics or blood transfusion services, clinical virology laboratories can be an optimal opportunity for HLA-B*57:01 testing since they receive blood samples for routine HIV monitoring and have the expertise for convenient and less expensive PCR-based point mutation assays.

OBJECTIVES

The Italian HLA-B*57:01 Network gathers accredited clinical virology laboratories offering HLA-B*57:01 testing in Italy with the aim to share protocols, test new methods, develop and maintain external quality assurance (EQA) programs.

STUDY DESIGN

A panel of 9HLA-B*57:01-positive and 16HLA-B*57:01-negative frozen blood samples were blindly distributed to 10 units including 9 clinical virology laboratories and one reference pharmacology laboratory. Each laboratory was free to use its own routine method for DNA extraction and HLA-B*57:01 testing.

RESULTS

DNA was extracted by automated workstations in 6 units and by manual spin columns in 4. Eight units used the Duplicα Real Time HLA-B*57:01 kit by Euroclone and two units used two different PCR homemade protocols. All the 10 units correctly identified all the 25 samples.

CONCLUSIONS

The first HLA-B*57:01 EQA program run in Italy showed that clinical virology units are equipped and proficient for providing HLA-B*57:01 testing by inexpensive assays easy to integrate into their routine.

HIV-1 Very Low Level Viremia Is Associated with Virological Failure in Highly Active Antiretroviral Treatment-Treated Patients

The aim of this study was to evaluate the impact of HIV-1 very low-level viremia (<50 copies/ml) on the 2-year risk of virological failure. A retrospective analysis including HIV-positive patients presenting two consecutive HIV RNA below 50 copies/ml (outpatient clinic in Italy, first semester of 2010) was performed. HIV RNA was measured through real time polymerase chain reaction (PCR) assay CAP/CTM HIV-1 version 2.0 (detection limit: 20 copies/ml) and stratified as undetectable RNA ("Target Not Detected", TND), <20 copies/ml, 20-50 copies/ml. After 96 weeks virological failure was defined as two consecutive viral loads above 50 copies/ml. Log-rank tests and a multivariate Cox proportional hazard model were used for univariate and multivariate analysis. A total of 1,055 patients (71.4% male, 87.4% white, aged 46.7 years) were included: nadir and current CD4 cell counts were 203 cells/mm(3) (106-292) and 554 cells/mm(3) (413-713.5). HIV RNA was undetectable in 781 patients (74%), <20 copies/ml in 190 patients (18%) and 20-50 copies/ml in 84 patients (8%). Virological failure was observed in 81 patients (7.7%); at multivariate analysis detectable RNA at baseline (p=0.017), HCV infection (p=0.020), more than three pills in the regimen (p=0.003), and duration of HIV RNA <50 copies/ml below 2 years (p<0.001) were independently associated with virological failure. In 14 patients newly selected resistance-associated mutations were observed. Undetectable HIV RNA by real-time PCR is significantly associated with a lower 2-year risk of virological failure along with Ab HCV negativity, longer viral control, and lower pill burden. Studies investigating the management of residual viremia under antiretroviral treatment are warranted.

Etiological diagnosis of bloodstream infections through a multiplex real-time polymerase chain reaction test in pediatric patients: a case series from a tertiary Italian hospital

BACKGROUND

The outcome of bloodstream infections (BSIs) is strongly related to microbiological diagnosis. Several factors may reduce blood culture (BC) diagnostic yield in pediatric BSIs, making the application of molecular methods quite promising.

METHODS

Multiplex real-time polymerase chain reaction (PCR) tests (the LightCycler Septifast Test MGRADE by Roche Diagnostics--LC-SF) performed in the tertiary centre of Regina Margherita Children's Hospital (Turin, Italy) over a 3-year period were retrospectively evaluated. Results of the LC-SF test were compared with those of BC (Automated Bact/Alert 3D, Biomerieux) collected at a close time point.

RESULTS

545 LC-SF tests were collected from 289 patients (183 males, median age 6.8 years, interquartile range (IQR) = 2.7-13.1); 163 had congenital or acquired immunodeficiency. In 515 cases (94.5%) the LC-SF test was performed with ongoing empirical antimicrobial therapy. Etiological definition was achieved in 111 BSI cases (20.4%). Both LC-SF and BC identified the responsible pathogen in 39 episodes. The LC-SF test alone gave a positive result in 29 septic episodes; BC alone permitted the etiological diagnosis in 43 episodes, but isolates were not included in the LC-SF master list in 10 cases. A 26% increase in bacterial identification chances due to the LC-SF test was documented. Cohen's kappa test indicated a moderate strength of agreement (0.49) between LC-SF tests and BCs closely collected.

CONCLUSIONS

BC remains the gold standard for the etiological diagnosis of BSIs, but PCR methods proved to be a valuable adjunctive diagnostic tool in pediatric BSIs, especially in children receiving empirical chemotherapy.

Combination of conventional blood cultures and the SeptiFast molecular test in patients with suspected sepsis for the identification of bloodstream pathogens

We evaluated performances of the molecular test SeptiFast (SF) for the detection of agents of bloodstream infection (BSI) in patients with suspected sepsis, the majority of them under antibiotic treatment and at high prevalence of HIV-1 infection (10.5%). Matched SF and blood culture (BC) samples (n=1186) from 1024 patients were studied. Two hundred fifty-one episodes of BSI out of 1144 were identified with the combined methods (22%). SF identified more episodes of BSI than BC: 206 versus 176 (χ(2)=7.008, P=0.0081) and a significantly higher number of Gram-negative bacteria than BC (77 versus 53, χ(2)=9.12; P=0.0025), as well as of polymicrobial infections (χ(2)=4.50, P=0.0339). In conclusion, SF combined with BC improved the diagnosis of sepsis, especially in immunocompromised patients.

Genotypic testing on HIV-1 DNA as a tool to assess HIV-1 co-receptor usage in clinical practice: results from the DIVA study group

PURPOSE

We have developed a sequencing assay for determining the usage of the genotypic HIV-1 co-receptor using peripheral blood mononuclear cell (PBMC) DNA in virologically suppressed HIV-1 infected patients. Our specific aims were to (1) evaluate the efficiency of V3 sequences in B versus non-B subtypes, (2) compare the efficiency of V3 sequences and tropism prediction using whole blood and PBMCs for DNA extraction, (3) compare the efficiency of V3 sequences and tropism prediction using a single versus a triplicate round of amplification.

RESULTS

The overall rate of successful V3 sequences ranged from 100 % in samples with >3,000 copies HIV-1 DNA/10(6) PBMCs to 60 % in samples with <100 copies total HIV-1 DNA /10(6) PBMCs. Analysis of 143 paired PBMCs and whole-blood samples showed successful V3 sequences rates of 77.6 % for PBMCs and 83.9 % for whole blood. These rates are in agreement with the tropism prediction obtained using the geno2pheno co-receptor algorithm, namely, 92.1 % with a false-positive rate (FPR) of 10 or 20 % and of 96.5 % with an FPR of 5.75 %. The agreement between tropism prediction values using single versus triplicate amplification was 98.2 % (56/57) of patients using an FPR of 20 % and 92.9 % (53/57) using an FPR of 10 or 5.75 %. For 63.0 % (36/57) of patients, the FPR obtained via the single amplification procedure was superimposable to all three FPRs obtained by triplicate amplification.

CONCLUSIONS

Our results show the feasibility and consistency of genotypic testing on HIV-1 DNA tropism, supporting its possible use for selecting patients with suppressed plasma HIV-1 RNA as candidates for CCR5-antagonist treatment. The high agreement between tropism prediction by single and triple amplification does not support the use of triplicate amplification in clinical practice.

A(H1N1)pdm09 hemagglutinin D222G and D222N variants are frequently harbored by patients requiring extracorporeal membrane oxygenation and advanced respiratory assistance for severe A(H1N1)pdm09 infection

Background

In patients with A(H1N1)pdm09 infection, severe lung involvement requiring admission to intensive care units (ICU) has been reported. Mutations at the hemagglutinin (HA) receptor binding site (RBS) have been associated with increased virulence and disease severity, representing a potential marker of critical illness.

Objectives

To assess the contribution of HA‐RBS variability in critically ill patients, A(H1N1)pdm09 virus from adult patients with severe infection admitted to ICU for extracorporeal membrane oxygenation support (ECMO) during influenza season 2009–2011 in Piemonte (4·2 million inhabitants), northwestern Italy, was studied.

Patients and methods

We retrospectively analyzed HA‐RBS polymorphisms in ICU patients and compared with those from randomly selected inpatients with mild A(H1N1)pdm09 disease and outpatients with influenza from the local surveillance program.

Results

By HA‐RBS direct sequencing of respiratory specimens, D222G and D222N viral variants were identified in a higher proportion in ICU patients (n = 8/24, 33·3%) than in patients with mild disease (n = 2/34, 6%) or in outpatients (n = 0/44) (Fisher's exact test P < 0·0001; OR 38·5; CI 95% 4·494–329·9). Eleven ICU patients died (42%), three of them carrying the D222G variant, which was associated with RBS mutation S183P in two. D222G and D222N mutants were identified in upper and lower respiratory samples.

Conclusions

A(H1N1)pdm09 HA substitutions D222G and D222N were harbored in a significantly higher proportion by patients with acute respiratory distress for A(H1N1)pdm09 severe infection requiring ICU admission and ECMO. These data emphasize the importance of monitoring viral evolution for understanding virus–host adaptation aimed at the surveillance of strain circulation and the study of viral correlates of disease severity.

Performance of genotypic tropism testing on proviral DNA in clinical practice: results from the DIVA study group

OBJECTIVE

The DIVA study is aimed at setting up a standardized genotypic tropism-testing on proviral-DNA for the routine clinical diagnostic-laboratory.

METHODS

Twelve local centres and 5 reference centres (previously cross-validated) were identified. For inter-center validation-procedure, 60 peripheral-blood mononuclear cells (PBMCs) aliquots from 45 HAART-treated patients were randomly chosen for population V3 sequencing on proviral-DNA at local HIV centre and at reference-laboratory. Viral tropism was predicted by Geno2Pheno algorithm (False Positive Rate [FPR] = 20%) as proposed by the European-Guidelines. Quantification of total HIV-1 DNA was based on a method described by Viard (2004).

RESULTS

Quantification of HIV-1 DNA was available for 35/45 (77.8%) samples, and gave a median value of 598 (IQR:252- 1,203) copies/10 PBMCs. A total of 56/60 (93.3%) samples were successfully amplified by both the reference and the local virological centers. The overall concordance of tropism prediction between local and reference centers was 54/56 (96.4%). Results of tropism prediction by local centers were: 33/54 (61.1%) R5 and 21/54 (38.9%) X4/DM.

CONCLUSION

There was high concordance in the genotypic tropism prediction based on proviral DNA among different virological centers throughout Italy. Our results are in line with other European studies, and support the use of genotypic tropism testing on proviral DNA in patients with suppressed plasma HIV-1 RNA candidate to CCR5-antagonist treatment.

Valganciclovir as pre-emptive therapy for cytomegalovirus infection post-allogenic stem cell transplantation: implications for the emergence of drug-resistant cytomegalovirus

OBJECTIVES

Valganciclovir is a well established drug for the management of cytomegalovirus (CMV) infection in haematopoietic stem cell transplantation (HSCT). Data concerning its safety regarding the development of drug resistance are required. The aim of the present study was to retrospectively investigate CMV drug resistance in a group of HSCT patients experiencing relapses of CMV infection after a first-line pre-emptive antiviral therapy.

METHODS

Thirteen adult HSCT patients out of 26 with asymptomatic CMV infection, experiencing relapsing infections 45-155 days after either intravenous (iv) ganciclovir (2 patients) or valganciclovir (11 patients), were studied. Genotypic assays for mutations in the viral phosphotransferase (UL97) and DNA-polymerase (UL54) genes were directly applied on patient specimens. Baseline CMV sequences were compared with those at the time of relapses to identify drug-resistant strains.

RESULTS

UL97 mutations A594V and M460V known to confer drug resistance developed in one relapsing patient who received iv ganciclovir as first-line therapy, corresponding to a rate of 7.7% of relapses due to drug-resistant strains and an overall 3.8% rate of infections due to CMV drug-resistant strains. UL54 drug resistance mutations were absent. No evidence of drug resistance was found in patients on valganciclovir either as first-line therapy or as treatment for relapses.

CONCLUSIONS

The safety profile of valganciclovir as anti-CMV pre-emptive therapy was confirmed, as well as that monitoring CMV drug resistance with genotypic tests on sequential isolates over the time-course of therapy offers guidance to tailor antiviral treatment in a clinically relevant time frame.

Clinical evaluation of the COBAS Ampliprep/COBAS TaqMan for HCV RNA quantitation in comparison with the branched-DNA assay

Diagnosis and monitoring of HCV infection relies on sensitive and accurate HCV RNA detection and quantitation. The performance of the COBAS AmpliPrep/COBAS TaqMan 48 (CAP/CTM) (Roche, Branchburg, NJ), a fully automated, real-time PCR HCV RNA quantitative test was assessed and compared with the branched-DNA (bDNA) assay. Clinical evaluation on 576 specimens obtained from patients with chronic hepatitis C showed a good correlation (r = 0.893) between the two test, but the CAP/CTM scored higher HCV RNA titers than the bDNA across all viral genotypes. The mean bDNA versus CAP/CTM log10 IU/ml differences were -0.49, -0.4, -0.54, -0.26 for genotype 1a, 1b, 2a/2c, 3a, and 4, respectively. These differences reached statistical significance for genotypes 1b, 2a/c, and 3a. The ability of the CAP/CTM to monitor patients undergoing antiviral therapy and correctly identify the weeks 4 and 12 rapid and early virological responses was confirmed. The broader dynamic range of the CAP/CTM compared with the bDNA allowed for a better definition of viral kinetics. In conclusion, the CAP/CTM appears as a reliable and user-friendly assay to monitor HCV viremia during treatment of patients with chronic hepatitis. Its high sensitivity and wide dynamic range may help a better definition of viral load changes during antiviral therapy.

Comparison of the Cobas Ampliprep/Cobas TaqMan HBV Test versus the Cobas Amplicor HBV monitor for HBV-DNA detection and quantification during antiviral therapy

Performances of the new automatic system COBAS AmpliPrep/COBAS TaqMan 48 (CAP/CTM) (Roche, Branchburg, NJ) for HBV DNA extraction and real-time PCR quantification were assessed and compared with the endpoint PCR COBAS AMPLICOR HBV Monitor (CAHBM, Roche). Analytical evaluation with proficiency panels from UK National External Quality Assessment Scheme (UK NEQAS) over a 1-year period of distribution showed that CAP/CTM correctly measured HBV DNA levels with a close correlation between expected and observed values (r=0.995). Clinical evaluation as tested with samples from 11 HBsAg-positive patients undergoing antiviral therapy (71 serial specimens of plasma), demonstrated excellent correlation with CAHBM (r=0.958, mean difference in quantitation: 0.14 log, IU/ml), but CAP/CTM detected longer period of residual viremia. HBV DNA reduction was much higher in the combination schedule (Lamivudine+Adefovir), than in Adefovir monotherapy (5.1 vs. 3.5 logs). In conclusion, CAP/CTM allows for an accurate and standardized quantification of HBV DNA in high through-put laboratories. Due to it high sensitivity, it may further improve the detection of emerging drug resistance strains and the assessment of antiviral therapy.

Oral valganciclovir as preemptive therapy for cytomegalovirus infection post allogeneic stem cell transplantation

Antiviral compounds including ganciclovir, foscarnet, and cidofovir are routinely used in the treatment of cytomegalovirus (CMV) infection and disease; however, these agents have a poor oral bioavailability and have the inconvenience and expense of intravenous administration.

AIM OF THE STUDY

To evaluate the safety and efficacy of oral valganciclovir (VGCV) for preemptive treatment of CMV reactivation in the setting of allogeneic hematopoietic stem cell transplantation (HSCT).

PATIENTS AND METHODS

We treated 15 patients receiving allogeneic HSCT from related (n=9) or unrelated (n=6) donors. In all patients, either the donor, host, or both were CMV Ig G positive pretransplant. Indication for therapy was preemptive treatment of CMV infection defined as one or two consecutive positive tests of pp65 antigenemia assay or CMV-polymerase chain reaction (PCR). VGCV was administered orally in a dosage of 900 mg b.i.d. for 2 weeks, followed by 450 mg b.i.d. for 2 additional weeks.

RESULTS

Patients developed a positive CMV-PCR after a median of 52 days (range 37-427) post HSCT and a positive pp65 antigenemia after a median time of 74 days (range 37-427) post HSCT. Preemptive treatment with VGCV was started a median time of 56 days (range 37-429) after transplant. In all, 11 patients (73%) completed the 28 days of therapy with VGCV. All patients showed a complete clearance of the virus. The median time to achieve a negative CMV-PCR was 6 days (range 4-18). A relapse of CMV infection after VGCV preemptive therapy occurred in 6 patients (40%). No patient developed early or late CMV disease. Six patients (40%) presented hematological toxicity including neutropenia and/or thrombocytopenia that required drug discontinuation in 4 cases.

CONCLUSION

VGCV administered as preemptive therapy for CMV infection in patients receiving an allogeneic HSCT showed promise for treating this frequent complication. Prospective randomized studies in this setting are mandatory to yield more definitive results.

COBAS AmpliPrep-COBAS TaqMan hepatitis B virus (HBV) test: a novel automated real-time PCR assay for quantification of HBV DNA in plasma

Success in antiviral therapy for chronic hepatitis B is supported by highly sensitive PCR-based assays for hepatitis B virus (HBV) DNA. Nucleic acid extraction from biologic specimens is technically demanding, and reliable PCR results depend on it. The performances of the fully automatic system COBAS AmpliPrep-COBAS TaqMan 48 (CAP-CTM; Roche, Branchburg, NJ) for HBV DNA extraction and real-time PCR quantification were assessed and compared to the endpoint PCR COBAS AMPLICOR HBV monitor (CAHBM; Roche). Analytical evaluation with a proficiency panel showed that CAP-CTM quantitated HBV DNA levels in one single run over a wide dynamic range (7 logs) with a close correlation between expected and observed values (r = 0.976, interassay variability below 5%). Clinical evaluation, as tested with samples from 92 HBsAg-positive patients, demonstrated excellent correlation with CAHBM (r = 0.966, mean difference in quantitation = 0.36 log(10) IU/ml). CAP-CTM detected 10% more viremic patients and longer periods of residual viremia in those on therapy. In lamivudine (LAM)-resistant patients, the reduction of HBV DNA after 12 months of Adefovir (ADF) was higher in the combination (LAM+ADF) schedule than in ADF monotherapy (5.1 logs versus 3.5 logs), suggesting a benefit in continuing LAM. CAP-CTM detected HBV DNA in liver biopsy samples from 15% of HBsAg-negative, anti-HBcAg-positive graft donors with no HBV DNA in plasma. The amount of intrahepatic HBV DNA was significantly lower in occult HBV infection than in overt disease. CAP-CTM can improve the management of HBV infection and the assessment of antiviral therapy and drug resistance, supporting further insights in the emerging area of occult HBV infection.

Burkholderia respiratory tract infections in Italian patients with cystic fibrosis: Molecular characterization

OBJECTIVES

To characterize by molecular techniques Burkholderia strains responsible for respiratory tract infections in cystic fibrosis (CF) patients (children and adults), to assign the Burkholderia cepacia complex (Bcc) isolates to a genomovar and to assess the presence of cblA and esmR genes in bacteria. Unique or sequential Burkholderia isolates (n=48) that had been collected from eight CF children and 17 adults over several (4-6) years were investigated; moreover 11 reference strains were analyzed.

METHODS

The microorganisms were identified by using biochemical methods, genotyped by pulse field gel electrophoresis (PFGE) and random-amplified polymorphic DNA fingerprinting-PCR (RAPD-PCR), and assessed by PCR assays for the genomovar and cblA and esmR genes of Bcc.

RESULTS

Among isolates 70.8% were identified as Bcc genomovar III-A; one child was infected by Burkholderia ambifaria and four adults were colonized with Burkholderia gladioli. The cblA gene was not detected in any of the isolates, while the esmR gene was detected in the 52.1% of the strains, all belonging to genomovar III-A.

CONCLUSION

Molecular analysis of strains revealed in CF patients a colonization with a persistent Burkholderia flora with strains of one genotype. The prevalence of Bcc of genomovar III-A in the two categories of patients and of B. gladioli in four adults demonstrated that transmission may have occurred between subjects. Moreover the B. ambifaria infection demonstrated in a child may be environmentally derived.

Quantitation of cytomegalovirus DNA by real-time polymerase chain reaction in peripheral blood specimens of patients with solid organ transplants: Comparison with end-point PCR and pp65 antigen test

The polymerase chain reaction (PCR) for cytomegalovirus (CMV) DNA quantitation provides sensitive and specific data for detecting CMV as well as monitoring the infection and determining the appropriate antiviral strategy. A recently introduced real-time PCR assay for CMV DNA quantitation was applied on 158 peripheral blood leukocytes (PBLs) from 32 liver-transplanted patients with CMV asymptomatic infection and correlated with a commercial quantitative end-point PCR (COBAS AMPLICOR CMV Monitor) and CMV pp65 antigenemia. A good correlation was found between real-time PCR and pp65 antigen test (r2 = 0.691) and the two PCR assays (r2 = 0.761). Real-time PCR data were higher in pre-emptive treated patients (>20 pp65 + positive cells, median CMV DNA value: 3.8 log(10) copies/500,000 PBLs) than in not-treated ones (2.9 logs). According to pp65 levels of 0, 1-10, 11-20, 21-50, 51-100, and >100 positive cells/200,000 PBLs, median CMV DNA by real-time PCR was 2.6, 3.0, 3.6, 4.0, 4.2, and 4.8 logs, respectively, (CMV DNA levels by COBAS AMPLICOR: 2.8, 2.9, 3.8, 3.7, 3.9, and 4.0 logs). For samples with >20 pp65 + cells, real-time PCR gave significantly higher values than in groups with <20 pp65 + cells, whereas the COBAS AMPLICOR results showed a slower progression rate. Dilutions of CMV AD169 strain were used to probe real-time PCR reproducibility (between and intra-assay variability <2%) and sensitivity (100% detection rate at 10 copies/reaction, 28.5% with end-point PCR). In conclusion, real-time PCR significantly improves the study of CMV DNA dynamics due to a more reliable quantitation of CMV DNA for moderate and high DNA level compared to end-point PCR with better sensitivity and specificity. Real-time PCR provides more precise information for evaluating infection progress and assessing antiviral response, simplifying and accelerating the process of producing a reliable quantitation of CMV DNA for clinical purposes.

Survey of phenotypic and genetic features of streptococcus pyogenes strains isolated in Northwest Italy

Streptococcus pyogenes (group A Streptococcus [GAS]) is an important pathogen whose virulence is related to the production of exotoxins and the presence of particular surface components. One hundred eighty-two GAS strains were collected in northwestern Italy between 1994 and 2002 and analyzed for phenotypic characteristics (opacity factor, proteolyic activity, and antimicrobial susceptibility) and by polymerase chain reaction for the presence of genes responsible for the production of exotoxins implicated in pathogenesis speA and speF and of prtF(1) (encoding fibronectin-binding protein F1). All strains were speF positive and 19.2% were speA positive and prtF(1) negative, whereas the prtF(1) gene was identified in 39.5% of the other strains. Of these, approximately half revealed the same pulse-field gel electrophoresis (PFGE) pattern but differed in both speA gene and macrolide resistance.

Antileishmanial activity of HIV protease inhibitors

The proteasomes of some protozoa are possible targets for chemotherapy. Leishmaniasis is a major health problem in human immunodeficiency virus (HIV) co-infected subjects. Two HIV protease inhibitors (PI), indinavir and saquinavir, have been shown to block proteasome functions; we therefore investigated their effects on the growth of two Leishmania spp. (Leishmania major and Leishmania infantum). After 24 h of treatment, both drugs exhibited a dose-dependent antileishmanial activity, with 50% lethal dose (LD50) values of, respectively, 8.3 microM and 7 microM on L. major; minor activity was observed on L. infantum. These results add new in vitro insights into the wide-spectrum efficacy of PI and suggest studying their action on amastigote forms of leishmania within macrophages in order to validate their potential contribution against opportunistic infections in treated seropositive patients.

Antimicrobial activity of euplotin C, the sesquiterpene taxonomic marker from the marine ciliate Euplotes crassus

Strains of the marine ciliate protist Euplotes crassus produce exclusive terpenoids called euplotins that play an ecological role. Among these derivatives, euplotin C is the main of four secondary metabolites isolated from cultures of this protozoon and represents the sesquiterpene taxonomic marker from E. crassus. Because different terpenoid metabolites of plant origin showed a certain antimicrobial activity, we assessed the compound euplotin C, purified by high-pressure liquid chromatography and solubilized in two solubility enhancers, against the protozoa Leishmania major and Leishmani infantum, the fungus Candida albicans, and nine strains of gram-positive and gram-negative microorganisms. An activity of euplotin C against Leishmania promastigotes was demonstrated (50% lethal doses were 4.6 or 8.1 microg/ml depending on the agent used to solubilize the compound), while the effect was less evident on Candida and nearly absent on bacteria. A nonsignificant cytotoxicity (50% lethal dose, >200 microg/ml) against the J774 cell line was observed. A leishmanicidal activity was also shown by the living, euplotin-producing cells of E. crassus cultured together with promastigotes; this activity increased with time from 10 min to 6 h of incubation. This study provides an initial rationale for the evaluation of euplotin C and other similar natural products as alternative or possibly synergistic compounds for current antiprotozoon chemotherapeutics.