Bernard Vandercam

Amplification-Based DNA Analysis in the Diagnosis of Prosthetic Joint Infection.

Microbiological cultures are moderately sensitive for diagnosing prosthetic joint infection (PJI). This study was conducted to determine whether amplification-based DNA methods applied on intraoperative samples could enhance PJI diagnosis compared with culture alone in routine surgical practice. Revision arthroplasty was performed for suspected PJI (n = 41) and osteoarthrosis control (n = 28) patients, and a diagnosis of PJI was confirmed in 34 patients. Amplification by polymerase chain reaction was performed on both 16S ribosomal DNA universal target genes and femA Staphylococcus-specific target genes. Species identification was achieved through amplicon sequencing. Amplification of the femA gene led to subsequent testing for methicillin resistance by amplification of the mecA gene. Microbiological and molecular assays identified a causative organism in 22 of 34 patients (64.7%) and in 31 of 34 patients (91.2%), respectively. In 18 of the 22 culture-positive patients, molecular and microbiological results were concordant for bacterial genus, species, and/or methicillin resistance. Bacterial agents were identified only by molecular methods in nine PJI patients, including seven who were receiving antibiotics at the time of surgery and one with recent but not concomitant antibiotherapy. DNA-based methods were found to effectively complement microbiological methods, without interfering with existing procedures for sample collection, for the identification of causative pathogens from intraoperative PJI samples, especially in patients with recent or concomitant antibiotherapy.

A double-blind comparison of itraconazole oral solution and fluconazole capsules for the treatment of oropharyngeal candidiasis in patients with AIDS.

This double-blind trial compared the clinical and mycological efficacy and safety of itraconazole oral solution with those of fluconazole capsules in the treatment of oropharyngeal candidiasis in patients with AIDS. A total of 244 patients were enrolled and randomized to one of three groups for treatment with itraconazole oral solution (100 mg twice daily for 7 days or 100 mg once daily for 14 days) or fluconazole capsules (100 mg once daily for 14 days). Among 194 evaluable cases, complete response (clearance of all symptoms and signs) or marked improvement was noted in 54 of 60 patients (90%) receiving once-daily itraconazole and in 65 of 72 fluconazole-treated patients (90%) at the end of treatment; these results were statistically equivalent (P = .0024). Twice-daily itraconazole produced a clinical response in 51 of 62 patients (82%). The groups were equivalent in terms of early relapse (within the 18-day period studied); 37% of patients in the twice-daily itraconazole group, 35% in the once-daily itraconazole group, and 34% in the fluconazole group relapsed. Drug tolerability was comparable between the three groups. These results show that, in the treatment of oropharyngeal candidiasis, itraconazole oral solution and fluconazole capsules at a 100-mg single daily dose for 14 days are equally effective.

Low molecular weight proteinuria in human immunodeficiency virus-infected patients

To determine whether human immunodeficiency virus (HIV) infection is associated with incipient tubular or glomerular defects, we determined the urinary excretion of four low molecular weight proteins (LMWP); beta2-microglobulin (U-beta2-m), cystatin C (U-cyst C), Clara cell protein (U-CC16), and retinol-binding protein (U-RBP), the markers of tubular dysfunction, the excretion of albumin (U-Alb), a marker of glomerular defect, and the excretion of N-acetyl-beta-D-glucosaminidase (U-NAG), a marker of structural damage of the proximal tubular epithelium. Their determinants have been assessed by stepwise regression analysis using as possible predictors age, sex, serum-beta2-m (S-beta2-m), CD4 lymphocyte count, or HIV infection stage and therapy. The study involved 76 HIV-infected patients without renal disease, 56 with S-beta2-m < 5 mg/L (Group B1), 20 with S-beta2-m > or = 5 mg/L (Group B2), and 30 HIV-negative controls. Fourteen patients (18.4%) had no abnormal urinary protein loss, and 62 (81.6%) had elevated urinary excretion of at least one protein (Alb, LMWP, or NAG). A single urinary protein was abnormal in 21 patients (U-beta2-m, n = 9; U-RBP, n = 2; U-CC16, n = 4; and U-Alb, n = 6). At least two LMWP were abnormal without increased U-Alb in 23 patients (12 with increased and 11 with normal U-NAG). Ten patients had an increased urinary excretion of at least one LMWP together with U-Alb (5 with increased and 5 with normal U-NAG). An increased urinary excretion of all proteins was observed in the last 8 patients. The average urinary excretion of all proteins (except cyst C) was significantly higher in HIV than in the control group. As expected, U-beta2-m and the prevalence of abnormal U-beta2-m values were higher in the B2 than in the B1 group (P = 0.0001), whereas the average urinary excretion and the prevalence of elevated values of Alb, LMWP (except beta2-m) or NAG were the same in both HIV groups. By stepwise regression analysis, age emerged as a significant determinant of urinary excretion of beta2-m and CC16, whereas male sex was associated with increased U-CC16. S-beta2-m, CD4-lymphocyte count, or HIV infection stage emerged as significant determinants only for U-beta2-m as a consequence of a close correlation between S-beta2-m and either HIV infection stage (r = -0.52, P = 0.0001), or CD4 count (r = -0.45, P = 0.0002). Over 80% of HIV-infected patients without overt renal disease have evidence of glomerular permeability defects or tubular dysfunction, whatever the stage of the disease. U-Alb, RBP, and CC16 appear as the most sensitive and reliable early markers of these abnormalities. Their cause and prognostic value remain to be determined.

Epidemiology and prevention of Clostridium difficile infections in a leukemia unit.

A 29-month prospective study was carried out in a leukemia unit with the aim of investigating the epidemiology ofClostridium difficileinfections and limiting their spread. Systematic cultures of stools and assays for cytotoxin were performed on patient admission and at weekly intervals, yielding 1,355 cultures and assays. The study period was divided in period A, before total unit renovation, and period B, afterwards. During period B all patient carriers ofClostridium difficilereceived vancomycin. A comparison of the two periods showed that the percentage of positive cultures fell from 16.6 % to 3.6 % and the positive toxin assays from 9.9% to 1.2%. It was concluded that colonization byClostridium difficilecan be prevented in hospital wards with generally high rates of infection by a combination of decontamination of the environment, introduction of preventive measures and treatment ofClostridium difficilecarriage with vancomycin.

Molecular characterization of femA from Staphylococcus hominis and Staphylococcus saprophyticus, and femA-based discrimination of staphylococcal species.

The femA gene encodes a protein precursor which plays a role in peptidoglycan biosynthesis in Staphylococcus aureus and is also considered as a factor influencing the level of methicillin resistance. A femA homologous gene was recently characterized in S. epidermidis, entailing the possibility of femA phylogenetic conservation in staphylococcal species. Accordingly, we assessed the presence of femA homologous genes in S. hominis and S. saprophyticus. Strategy for identification relied upon alignment of S. aureus and D. epidermidis femA sequences and upon identification of potentially conserved regions. Amplifications of portions of the femA genes were performed under permissive annealing conditions, by using several sets of primers designed to match the consensus regions. DNA sequencing of overlapping PCR fragments led to the characterization of the entire femA genes of S. hominis and S. saprophyticus, and provided more precise information on the femA start codon for all five species. The genomic organization of all these femA genes appeared highly conserved, with alternance of homologous and variable regions. On this basis, a consensus sequence of the femA gene was defined and interspecies variations were exploited to design strategies for staphylococci species-specific identification, including multiplex PCR amplification and a reverse hybridization assay.

Influence of host genetic factors on efavirenz plasma and intracellular pharmacokinetics in HIV-1-infected patients

BACKGROUND Efavirenz (EFV) is characterized by interindividual pharmacokinetic variability causing inconsistent clinical responses. Previous studies have identified some possible genetic determinants of the variability in plasma concentrations. However, their impact on EFV intracellular pharmacokinetics remains mostly unexplored. AIMS To confirm previous observations concerning the influence of genetic polymorphisms on EFV plasma concentrations and to assess their effect on the intracellular pharmacokinetics of EFV. MATERIALS & METHODS EFV concentrations in plasma ([EFV](Cmin)) and in peripheral blood mononuclear cells ([EFV](CC)) were determined in 50 HIV-infected patients. Subjects were genotyped for 13 polymorphisms in 5 different genes (CYP2A6, CYP2B6, CYP3A5, UGT2B7 and ABCB1). Relationships between genetic status and [EFV](Cmin), [EFV](CC) or EFV accumulation in peripheral blood mononuclear cells (EFV accumulation ratio or accumulation ration [AR]) were then evaluated. RESULTS CYP2B6 allelic status was associated with differences in [EFV](Cmin) but also in [EFV](CC). Patients carrying at least one mutated allele showed significantly higher [EFV](Cmin) and [EFV](CC) than homozygous wild-type (mutated homozygous [m/m] >heterozygous [wt/m]>homozygous wild-type [wt/wt], p<0.001). ABCB1 rs3842T>C was significantly associated with higher EFV AR (p = 0.032). Finally, the ABCB1 3435C>T SNP was associated with a lower increase in CD4-cell count after EFV therapy initiation. CONCLUSION Our study corroborates previous findings indicating that knowledge of CYP2B6 genetic status should be taken into account for an EFV treatment. Our results also constitute the first demonstration of the significant influence of CYP2B6 genetic polymorphisms on [EFV](CC) and suggest that ABCB1 SNPs may also influence the clinical impact of EFV treatment.

Infectious complications after 2-chlorodeoxyadenosine therapy.

Abstract: Infection is a common adverse event after therapy with nucleoside analogs, including 2‐chlorodeoxyadenosine (CdA). However, the incidence of CdA‐related infections has been poorly documented. In this study we compare, in the same patient population, the incidence of infectious episodes during the 6‐month period before CdA to their incidence during the 6 months after initiating therapy. Ninety‐five patients with hematological malignancies were studied. The incidence of infectious episodes almost doubled after CdA (0.87 vs. 0.47 during the pre‐CdA period). The following factors were associated with an increased risk of infection after therapy: a history of previous chemotherapy, infection during the pre‐CdA period and a diagnosis of chronic lymphocytic leukemia or of non‐Hodgkins lymphoma. Age, neutrophil and lymphocyte count at onset of CdA and time interval between diagnosis and therapy with CdA did not correlate with the infectious risk. The pattern of infections was modified after therapy with an increase of herpes virus infections (1 vs. 8 episodes, p = 0.04) and of fever of unknown origin (6 vs. 17 episodes, p = 0.03). In conclusion, a population at high risk for developing infectious complications after CdA therapy can be identified. Specific measures aimed at reducing the incidence of infectious events should concentrate on this population.

Elevation of serum thyroxine-binding globulin (but not of cortisol-binding globulin and sex hormone-binding globulin) associated with the progression of human immunodeficiency virus infection.

PURPOSE In order to assess the relation of thyroid function tests to human immunodeficiency virus (HIV) infection, we determined the levels of serum thyroid hormones, serum binding proteins [thyroxine-binding globulin (TBG), cortisol-binding globulin (CBG), and sex hormone-binding globulin (SHBG)], and serum tumor necrosis factor (TNF) in HIV-seropositive subjects at different clinical stages. PATIENTS AND METHODS Thirty-seven HIV-seropositive patients were studied: 7 at stage II, 13 at stage III, and 17 at stage IV (eight ambulatory and nine hospitalized) according to the Centers for Disease Controls criteria. RESULTS As compared with stage II and stage III patients, stage IV patients had significantly higher mean TBG and total thyroxine (TT4) values, similar and normal total triiodothyronine (TT3) levels, and similar and abnormally low reverse triiodothyronine (rT3) concentrations. However, stage IV hospitalized patients had significantly lower TT3 values than stage IV ambulatory patients. In contrast to TBG, mean levels of CBG and SHBG were comparable in the three groups and within normal limits. For the whole population of HIV patients, there was a highly significant correlation between the CD4 lymphocyte count and TBG (r = -0.529, p less than 0.001) but not with CBG and SHBG levels. Finally, TNF values higher than 10 pg/mL were detected in six of the 17 stage IV patients and in only one of the 13 stage III patients (p = 0.059); elevated TNF levels correlated with a lower CD4 count (p less than 0.01) but not with serum TBG levels. CONCLUSION The progression of HIV infection is associated with an elevation of serum TNF and TBG, but not of CBG or SHBG. HIV-infected patients have an unexpectedly normal TT3-low rT3 state.

Prevalence and epidemiology of HIV type 1 drug resistance among newly diagnosed therapy-naive patients in Belgium from 2003 to 2006.

This study is the first prospective study to assess the prevalence, epidemiology, and risk factors of HIV-1 drug resistance in newly diagnosed HIV-infected patients in Belgium. In January 2003 it was initiated as part of the pan-European SPREAD program, and continued thereafter for four inclusion rounds until December 2006. Epidemiological, clinical, and behavioral data were collected using a standardized questionnaire and genotypic resistance testing was done on a sample taken within 6 months of diagnosis. Two hundred and eighty-five patients were included. The overall prevalence of transmitted HIV-1 drug resistance in Belgium was 9.5% (27/285, 95% CI: 6.6-13.4). Being infected in Belgium, which largely coincided with harboring a subtype B virus, was found to be significantly associated with transmission of drug resistance. The relatively high rate of baseline resistance might jeopardize the success of first line treatment as more than 1 out of 10 (30/285, 10.5%) viruses did not score as fully susceptible to one of the recommended first-line regimens, i.e., zidovudine, lamivudine, and efavirenz. Our results support the implementation of genotypic resistance testing as a standard of care in all treatment-naive patients in Belgium.

Meropenem versus ceftazidime as empirical monotherapy for febrile neutropenic cancer patients.

Abstract A total of 101 cancer patients with 121 febrile neutropenia episodes were randomised to receive empirical treatment with i.v. meropenem (1 g/8 h) or ceftazidime (2 g/8 h). After 3 days, 89% of patients were on unmodified therapy in the meropenem group, compared with 83% in the ceftazidime group. Of the evaluable episodes (n=106), the success rate with unmodified empirical therapy until the end of the treatment course was slightly higher with meropenem than with ceftazidime (48% vs 38%, P=0.39). Furthermore, initial success with further infections was observed in 22% of episodes treated with meropenem and in 13% of episodes treated with ceftazidime. Glycopeptides were used as first modification in 28% and 39% of meropenem and ceftazidime recipients, respectively. Both treatments were well tolerated and there were no reports of drug-related nausea/vomiting or seizures. No significant differences in response rate or in tolerability were observed when analysing only the first febrile episodes. In conclusion, meropenem seems to be as efficacious and well tolerated as ceftazidime and may be associated with a lesser requirement for the addition of glycopeptides.