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BackgroundThe COVIH study is a prospective coronavirus disease 2019 (COVID-19) vaccination study in 1154 people with HIV (PWH), of whom 14% showed reduced antibody levels after primary vaccination. We evaluated whether an additional vaccination boosts immune responses in these hyporesponders.MethodsThe primary end point was the increase in antibodies 28 days after additional mRNA-1273 vaccination. Secondary end points included neutralizing antibodies, S-specific T-cell and B-cell responses, and reactogenicity.ResultsOf the 66 participants, 40 previously received 2 doses ChAdOx1-S, 22 received 2 doses BNT162b2, and 4 received a single dose Ad26.COV2.S. The median age was 63 years (interquartile range [IQR], 60–66), 86% were male, and median CD4+ T-cell count was 650/μL (IQR, 423–941). The mean S1-specific antibody level increased from 35 binding antibody units (BAU)/mL (95% confidence interval [CI], 24–46) to 4317 BAU/mL (95% CI, 3275–5360) (P < .0001). Of all participants, 97% showed an adequate response and the 45 antibody-negative participants all seroconverted. A significant increase in the proportion of PWH with ancestral S-specific CD4+ T cells (P = .04) and S-specific B cells (P = .02) was observed.ConclusionsAn additional mRNA-1273 vaccination induced a robust serological response in 97% of PWH with a hyporesponse after primary vaccination.Clinical Trials Registration. EUCTR2021-001054-57-N.

Background & Aims: Patients with chronic or resolved hepatitis B are at risk of hepatitis B reactivation (HBVr) when treated with high-risk immunosuppressive therapy such as rituximab. Therefore, international guidelines recommend HBV screening prior to rituximab treatment and subsequent antiviral prophylaxis among patients with a (resolved) infection. In this study, we evaluated the adherence to those recommendations. Methods: This is a retrospective multicentre study including patients treated with rituximab between 2000-2021. Performance of correct screening was assessed, defined as the measurement of hepatitis B surface antigen (HBsAg) and hepatitis B core antibodies (anti-HBc). Next, initiation of antiviral prophylaxis and HBVr rate among patients with a chronic or resolved HBV infection was studied. Results: We enrolled 3,176 patients of whom 1,448 (46%) were screened correctly. Screening rates differed significantly between academic and non-academic hospitals; respectively 65% vs 32% (p

Background: Invasive mechanical ventilation is the treatment of choice in COVID-19 patients when hypoxemia persists, despite maximum conventional oxygen administration. Some frail patients with severe hypoxemic respiratory failure are deemed not eligible for invasive mechanical ventilation. Objectives: To investigate whether High-flow nasal cannula (HFNC) in the wards could serve as a rescue therapy in these frail patients. Methods: This retrospective cohort study included frail COVID-19 patients admitted to the hospital between March 9th and May 1st 2020. HFNC therapy was started in the wards. The primary endpoint was the survival rate at hospital discharge. Results: Thirty-two patients with a median age of 79.0 years (74.5–83.0) and a Clinical Frailty Score of 4 out of 9 (3–6) were included. Only 6% reported HFNC tolerability issues. The overall survival rate was 25% at hospital discharge. Conclusions: This study suggests that, when preferred, HFNC in the wards could be a potential rescue therapy for respiratory failure in vulnerable COVID-19 patients.

Background: In the midst of the COVID-19 crisis, many frail elderly adults were admitted to our hospital with COVID-19. Some faced severe respiratory failure but were not eligible for invasive mechanical ventilation, due to frailty, functional status, comorbidity or wish of the patient. Our main objective was to investigate whether High-flow nasal cannula (HFNC) treatment on the wards could be an effective alternative treatment for these patients.Methods: A retrospective cohort study amongst COVID-19 adult patients with respiratory failure defined as persisting hypoxemia despite maximum conventional oxygen administration requiring invasive mechanical ventilation in the Intensive Care Unit (ICU) but being treated with HFNC as they were non-eligible due to frailty or wish of the patient.Results: The study included 32 patients between March 9th and May 1st, 2020. The median age was 79.0 years (74.5-83.0) with a median of three comorbidities (3-4) and a median Clinical Frailty Score of 4 out of 9 (3-6). The median SpO2/FiO2 Ratio was 157.5 indicating moderate ARDS. Overall survival rate in the HFNC cohort was 25%. Age (80.5 (78.0-84.3) vs 69.5 (65.5-74.3) p=0.0040) and hypertension (92% vs 25%, p=0.0008) were correlated with mortality.Conclusion: This study suggests that HFNC could be an effective last resort respiratory management strategy for respiratory failure in vulnerable elderly COVID-19 patients who failed on conventional high dose oxygen supply and are not eligible for invasive mechanical ventilation.

Hypercoagulation is one of the most distinct prognostic factors of patients with COVID-19 and has been associated with arterial thrombosis and other venous thrombotic events (VTE). Bleeding complications are far less encountered. The International Society on Thrombosis and Haemostasis (ISTH) guidance advises giving prophylactic low-molecular-weight heparin (LMWH) to prevent these events, although there is evidence that the incidence remains high despite using prophylactic LMWH. We describe three cases of COVID-19 pneumonia that were admitted to our intensive care unit (ICU) and developed acute pulmonary embolisms (APE) despite high dosage prophylactic LMWH. These cases raise concerns about using prophylactic LMWH instead of therapeutic anticoagulation in severe and critically COVID-19 patients., Highlights • Hypercoagulation is one of the most distinct prognostic factors in COVID-19. • Despite prophylactic LMWH COVID-19 patients develop thrombotic complications. • Immune-thrombosis is a potential mechanism contributing to thrombotic complications.

Structured abstract for full paperBackgroundAfter recovery from COVID-19, most patients have anti-SARS-CoV-2 neutralizing antibodies. Their convalescent plasma could be an inexpensive and widely available treatment for COVID-19.MethodsThe Convalescent-plasma-for-COVID (ConCOVID) study was a randomized trial comparing convalescent plasma with standard of care therapy in patients hospitalized for COVID-19 in the Netherlands. Patients were randomized 1:1 and received 300ml of plasma with anti-SARS-CoV-2 neutralizing antibody titers of at least 1:80. The primary endpoint was day-60 mortality and key secondary endpoints were hospital stay and WHO 8-point disease severity scale improvement on day 15.ResultsThe trial was halted prematurely after 86 patients were enrolled. Although symptomatic for only 10 days (IQR 6-15) at the time of inclusion, 53 of 66 patients tested had anti-SARS-CoV-2 antibodies at baseline. A SARS-CoV-2 plaque reduction neutralization test showed neutralizing antibodies in 44 of the 56 (79%) patients tested with median titers comparable to the 115 donors (1:160 vs 1:160, p=0.40). These observations caused concerns about the potential benefit of convalescent plasma in the study population and after discussion with the data safety monitoring board, the study was discontinued. No difference in mortality (p=0.95), hospital stay (p=0.68) or day-15 disease severity (p=0.58) was observed between plasma treated patients and patients on standard of care.ConclusionMost COVID-19 patients already have high neutralizing antibody titers at hospital admission. Screening for antibodies and prioritizing convalescent plasma to risk groups with recent symptom onset will be key to identify patients that may benefit from convalescent plasma. Clinicaltrials.gov:NCT04342182

Background: In the midst of the COVID-19 crisis, many frail elderly were admitted to our hospital with COVID-19. We sought a treatment for those who had severe respiratory failure but were not eligible for invasive mechanical ventilation, due to frailty, functional status, comorbidity or wish of the patient. We started with applying High-flow nasal cannula (HFNC) treatment on the wards.Methods: A retrospective cohort study amongst COVID-19 adult patients with respiratory failure defined as persisting hypoxemia despite maximum conventional oxygen administration requiring invasive mechanical ventilation at the Intensive Care Unit (ICU) but being treated with HFNC as they were non-eligible due to frailty or wish of the patient.Results: We included 32 patients between March 9 and May 1, 2020. The median age was 79.0 years (74.5-83.0) with a median of three comorbidities (3-4) and a median Clinical Frailty Score of 4 out of 9 (3-6). The median SPO2/FiO2 Ratio was 157.5 indicating moderate ARDS. Overall survival rate in the HFNC cohort was 25%. Age (80.5 (78.0-84.3) vs 69.5 (65.5-74.3) p=0.0040) and hypertension (92% vs 25%, p=0.0008) were associated with mortality.Conclusion: HFNC can be used as a last resort respiratory management strategy in vulnerable elderly COVID-19 patients in respiratory failure on the wards who failed on conventional high dose oxygen supply and are not eligible for invasive mechanical ventilation.

Objectives: Voriconazole, like all other antifungals of the azole group, is potentially hepatotoxic. A large interpatient variability of liver enzyme elevations during oral or intravenous (iv) voriconazole administration is observed. This interpatient variability may be explained by differences in voriconazole metabolism because of cytochrome P450 polymorphisms. We examined the relationship between cytochrome P450 polymorphisms and hepatotoxicity in immunocompromised patients predominantly receiving oral formulations of voriconazole. Methods: In a single institution retrospective study of 86 immunocompromised patients receiving oral (n 5 74) or iv (n 5 12) voriconazole, we studied the influence of cytochrome P450 polymorphisms (CYP2C19, CYP2C9 and CYP3A5) on the maximum bilirubin and serum liver enzyme levels [alkaline phosphatase, gamma-glutamyl transpeptidase (GGT), serum aspartate aminotransferase and serum alanine aminotransferase] and their respective common toxicity criteria scores (CTC-scores). Results: Median serum bilirubin as well as the level of all other liver enzymes increased during voriconazole treatment. A decline in CTC-score was observed in zero (0%) to six (7%) patients; an increase in CTC-score was demonstrated in 36 (42%) to 54 (63%) patients. No statistically significant differences in maximum value or maximum increase of liver enzymes or CTC-score in relation to cytochrome P450 polymorphisms were observed. Only a trend towards higher maximum CTC-score of GGT for wild-type of CYP2C9 was observed (P 5 0.046). Conclusions: No significant relationship between CYP2C9, CYP2C19 or CYP3A5 polymorphisms and serum liver enzyme levels was observed in patients treated with voriconazole.

The purpose of this study was to describe the nonlinear pharmacokinetics of piperacillin observed during intermittent infusion and continuous infusion by using a nonparametric population modeling approach. Data were 120 serum piperacillin concentration measurements from eight adult cystic fibrosis (CF) patients. Individual pharmacokinetic parameter estimates during intermittent infusion or continuous infusion were calculated by noncompartmental analysis and with a maximum iterative two-stage Bayesian estimator. To simultaneously describe concentration-time data during intermittent infusion and continuous infusion, nonlinear models were parameterized as two-compartment Michaelis-Menten models. Models were fit to the data with the nonparametric expectation maximization algorithm. The calculations were executed on a remote supercomputer. Nonlinear models were evaluated by log-likelihood estimates, residual plots, and R 2 values, and predictive performance was based on bias (mean weighted error [MWE]) and precision (mean weighted square error [MWSE]). A linear pharmacokinetic model could not describe combined intermittent infusion and continuous infusion data well. A good population model fit to the intermittent infusion and continuous infusion data was obtained with the constructed nonlinear models. Maximum a posteriori probability (MAP) Bayesian R 2 values for the nonlinear models were 0.96 to 0.97. Median parameter estimates for the best nonlinear model were as follows: K m , 58 ± 75 mg/liter (mean and standard deviation); V max , 1,904 ± 1,009 mg/h; volume of distribution of the central compartment, 14.1 ± 3.0 liters; k 12 , 0.63 ± 0.41 h −1 ; and k 21 , 0.37 ± 0.19 h −1 . The median bias (MWE) and precision (MWSE) values for MAP Bayesian estimation with the Michaelis-Menten model were 0.05 and 4.6 mg/liters, respectively. The developed nonlinear pharmacokinetic models can be used to optimize piperacillin therapy administered via continuous infusion in patients with CF and have distinct advantages over conventional linear models.

Combination therapy with antimicrobial agents can be used against bacteria that have reduced susceptibilities to single agents. We studied various tobramycin and ceftazidime dosing regimens against four resistant Pseudomonas aeruginosa strains in an in vitro pharmacokinetic model to determine the usability of combination therapy for the treatment of infections due to resistant bacterial strains. For the selection of an optimal dosing regimen it is necessary to determine which pharmacodynamic parameter best predicts efficacy during combination therapy and to find a simple method for susceptibility testing. An easy-to-use, previously described E-test method was evaluated as a test for susceptibility to combination therapy. That test resulted in a MIC combi , which is the MIC of, for example, tobramycin in the presence of ceftazidime. By dividing the tobramycin and ceftazidime concentration by the MIC combi at each time point during the dosing interval, fractional inhibitory concentration (FIC) curves were constructed, and from these curves new pharmacodynamic parameters for combination therapy were calculated (i.e., AUC combi , C max-combi , T >MIC-combi , and T >FICi , where AUC combi , C max-combi , T >MIC-combi , and T >FICi are the area under the FIC combi curve, the peak concentration of FIC combi , the time that the concentration of the combination is above the MIC combi , and the time above the FIC index, respectively). By stepwise multilinear regression analysis, the pharmacodynamic parameter T >FICi proved to be the best predictor of therapeutic efficacy during combination therapy with tobramycin and ceftazidime ( R 2 = 0.6821; P < 0.01). We conclude that for combination therapy with tobramycin and ceftazidime the T >FICi is the parameter best predictive of efficacy and that the E-test for susceptibility testing of combination therapy gives promising results. These new pharmacodynamic parameters for combination therapy promise to provide better insight into the rationale behind combination therapy.

The influence of half-life on the postantibiotic effect (PAE) of tobramycin against Pseudomonas aeruginosa and Staphylococcus aureus was investigated during one dosing interval. Tobramycin half-lives of 0.5 to 2.5 h were simulated in an in vitro model, and the PAE was determined by an enzymatic inactivation method at different time points, i.e., when the tobramycin concentrations were 20×, 5×, and 1× the MIC. At the time point during therapy when the tobramycin concentrations had declined to 1× the MIC, at a tobramycin half-life of 0.5 h, the times of the PAEs were approximately 0.7 and 1.7 h for P. aeruginosa and S. aureus , respectively, and the PAE disappeared completely at half-lives corresponding to those found in humans (i.e., 2 to 2.5 h). The PAE itself cannot be fully explained by the presence of free intrabacterial tobramycin or the emergence of resistant subpopulations. The explanation for the disappearance of the PAE during the dosing interval may therefore be explained by the repair of sublethal damage. Since the standard method of determining the PAE in animal models is somewhat different from the method used for measurement of the PAE in vitro, the conditions under which the PAE is measured in vivo were also simulated in the in vitro model. This resulted in PAEs longer than those found by the standard method of obtaining in vitro PAE measurements. We conclude that the PAE of tobramycin, as determined by conventional in vitro methods, has virtually no clinical importance. PAEs determined in vivo may have some clinical relevance, but they are probably primarily caused by sub-MIC effects.

Contains fulltext : 167321.PDF (Publisher’s version ) (Open Access) BACKGROUND: Approval of drugs in chronic hepatitis C is supported by registration trials. These trials might have limited generalizability through use of strict eligibility criteria. We compared effectiveness and safety of real world hepatitis C patients eligible and ineligible for registration trials. METHODS: We performed a nationwide, multicenter, retrospective cohort study of chronic hepatitis C patients treated in the real world. We applied a combined set of inclusion and exclusion criteria of registration trials to our cohort to determine eligibility. We compared effectiveness and safety in eligible vs. ineligible patients, and performed sensitivity analyses with strict criteria. Further, we used log binomial regression to assess relative risks of criteria on outcomes. RESULTS: In this cohort (n = 467) 47% of patients would have been ineligible for registration trials. Main exclusion criteria were related to hepatic decompensation and co-morbidity (cardiac disease, anemia, malignancy and neutropenia), and were associated with an increased risk for serious adverse events (RR 1.45-2.31). Ineligible patients developed significantly more serious adverse events than eligible patients (27% vs. 11%, p< 0.001). Effectiveness was decreased if strict criteria were used. CONCLUSIONS: Nearly half of real world hepatitis C patients would have been excluded from registration trials, and these patients are at increased risk to develop serious adverse events. Hepatic decompensation and co-morbidity were important exclusion criteria, and were related to toxicity. Therefore, new drugs should also be studied in these patients, to genuinely assess benefits and risk of therapy in the real world population.

Background. In human immunodeficiency virus (HIV)-infected patients, the immunogenicity of hepatitis B vaccines is impaired. The primary and secondary aims of our study were to investigate the effectiveness and compliance of 2 different vaccination regimen in an HIV-infected population. Methods. A noninferiority trial with a 10% response margin was designed. Included were patients >= 18 years old, with negative HBsAg/anti-HBc serology, and not previously vaccinated against hepatitis B. Patients were stratified according to CD4(+) cell count: 500. Participants received 10 mu g HBvaxPRO intramuscularly according to a 0-1-3 week schedule or the standard 0-4-24 week schedule. Anti-HBs levels were measured at week 28, considered protective >= 10 IU/L. Results. Modified intention to treat analysis in 761 patients was performed. Overall response difference was 50%(standard arm) versus 38.7% (accelerated arm) =11.3% (95% confidence interval [CI], [4.3, 18.3]), close to the 10% response margin. In CD4(+) cell count group 200-500 cells/mm(3), the response difference was 20.8% (95% CI [10.9, 30.7]). However, the response difference in CD4(+) cell count group >500 cells/mm(3) was -1.8% (95% CI [-13.4,+9.7]). Compliance was significantly superior with the accelerated schedule, 91.8% versus 82.7% (P 500 cells/mm(3).

In 2002 a 73-year-old woman (non-smoking, medical history of allergic rhinitis) was referred to a rheumatologist because of synovitis of the metacarpophalangeal and proximal interphalangeal joints of both hands which had slowly developed over 3 months. Late-onset rheumatoid arthritis was suspected. Morning stiffness, rheumatoid nodules, erosions of cartilage or bone, rheumatoid factor and antibodies to cyclic citrullinated peptides were absent. Prednisone (2.5–5 mg daily) and non-steroidal anti-inflammatory drugs were started. In 2004 she was referred …

Objectives: Absorption of oral voriconazole is good and in contrast to the intravenous (iv) formulation it can be given in patients with renal insufficiency. Furthermore, the acquisition costs are significantly lower. The aim of this study was to compare the incidence of hepatotoxicity in patients treated with the oral formulation of voriconazole with that in patients treated with the iv formulation. Methods: This was a retrospective observational study. A total of 35 patients with haematological disease and an invasive fungal infection were treated with oral voriconazole during the entire regimen. We compared the incidence of hepatotoxicity with that in 11 patients treated intravenously during the first week. Results: The incidence of increased liver enzymes was comparable between both groups. Voriconazole was discontinued in two patients in the oral group and one patient in the iv group because of hepatotoxicity. The incidence of liver enzyme elevations in the entire study cohort of 46 patients was higher than that previously reported in a comparable study population (P < 0.001). However, clinically significant hepatotoxicity was infrequently observed (3/46 or 6.5%). Conclusions: In 35 patients with invasive fungal infections we instituted oral voriconazole therapy from day 1 and found an incidence of hepatotoxicity comparable to 11 controls treated intravenously.

Objective An acute hepatitis C virus (HCV) infection in an HIV-positive man who had sex with men (MSM) was notified. In the period of his seroconversion he was also diagnosed with a rectal lymphogranuloma venereum (LGV) infection, and was part of a cluster of 15 LGV cases in 2003. Our aim was to investigate HCV transmission and to search for potential spread among sexual contacts and known LGV patients. Methods Our case series included the index, two recent contacts, and 14 LGV cases. They were interviewed about parenteral exposure for HCV, history of sexually transmitted diseases(STDs), sexual behaviour and drug use. Laboratory investigations included anti-HCV antibodies, HCV-polymerase chain reaction, and HCV genotyping. Results Seven out of 17 MSM recently seroconverted for HCV (41%). Three genotypes were found. Parenteral risk factors were excluded. Six out of seven had LGV proctitis coinciding with HCV seroconversion, six (86%) were HIV infected. Unprotected anal contact was practised by both HCV uninfected and infected cases. Unprotected active and passive fisting was reported by all seven HCV infected men, compared with two of nine uninfected men (P = 0.003). Non-intravenous drug use during sexual activities was common among all MSM. Numerous, often anonymous, sexual contacts in various European countries were reported. Conclusions A cluster of acute HCV infection is reported among mostly HIV-positive MSM, with multiple partners throughout Europe. Sexual techniques potentially leading to mucosal damage (fisting), concomitant STDs such as LGV and drug use seem facilitating factors for spread. Extensive case finding and partner tracing is advocated as well as targeted prevention messages.

To the Editor: Mycobacterium haemophilum is an aerobic, slow-growing microorganism with optimal growth at 30°C to 32°C. It has a unique requirement for ferric iron–containing compounds (1), from which it acquired its name (i.e., haemophilum). Infections with M. haemophilum are rare, but cervicofacial lymphadenitis caused by M. haemophilum has been described in children (2). Besides cervicofacial lymphadenitis, extrapulmonary signs of M. haemophilum disease include subcutaneous noduli, arthritis, and osteomyelitis, which generally affect immunocompromised patients (3). Recently, 2 cases of cutaneous M. haemophilum infections after alemtuzumab treatment were reported (4). A small number of pulmonary M. haemophilum infections associated with AIDS or solid organ or bone marrow transplantation have been described (1). We report pulmonary M. haemophilum infection in a woman who had been immunosuppressed by tumor necrosis factor-α antagonist (TNF-αA) (adalimumab) treatment for rheumatoid arthritis. A 72-year-old woman with a history of rheumatoid arthritis and obstructive sleep apnea syndrome had signs and symptoms of fatigue, mild fever episodes, and a nonproductive cough 9 months after treatment for rheumatoid arthritis had begun with methotrexate (MTX) and TNF-αA. Physical examination was unremarkable except for a body temperature of 38.9°C. Laboratory testing showed an increased erythrocyte sedimentation rate (ESR) (77 mm/h), an increased C-reactive protein (CRP) level (60 mg/L), a normal leukocyte count (8,500 cells/μL), and relative monocytosis (12%). HIV serologic testing results were negative. Chest radiograph showed an infiltrate in the right upper lobe. Chest computed tomography confirmed this finding and showed lymphadenopathy in the right hilus and mediastinum. Notably, the tuberculin skin test result was negative at screening before she began the TNF-αA treatment, but was now positive (20 mm), suggesting mycobacterial infection. Auramine and Ziehl-Neelsen staining of sputum and bronchoalveolar liquids showed no acid-fast bacilli, and M. tuberculosis infection was not confirmed by PCR or culture. Eventually, a mediastinal lymph node biopsy was taken by endoscopic ultrasound guidance. Granulomatous inflammation and acid-fast bacilli were seen by microscopy. Corresponding cultures yielded a strain identified as M. haemophilum at the Netherlands National Institute for Public Health and the Environment (RIVM) by using the Inno-LiPA Mycobacteria v2 reverse line blot assay (Innogenetics, Ghent, Belgium). Strain identity was confirmed by sequencing of the complete 16S rDNA gene, which was identical to that of M. haemophilum available in the GenBank sequence database (National Center for Biotechnology Information; www.ncbi.nlm.nih.gov; accession no. {"type":"entrez-nucleotide","attrs":{"text":"X88923","term_id":"2832581"}}X88923). The RIVM performed drug susceptibility testing by using a modified agar dilution method (5). Middlebrook 7H10 media were enriched with 10% sheep blood hemolyzed by 1:1 dilution with water and subsequent freezing–thawing. Historic drug susceptibility data was reviewed (Table). Initially, adalimumab was discontinued, and our patient was treated with isoniazid, ethambutol, rifampin, and pyrazinimide because M. tuberculosis infection was suspected. After identification of M. haemophilum, our patient was treated with rifampin and azithromycin. A total treatment duration of 10 months resulted in complete resolution of the pulmonary infiltrate and normalization of ESR and CRP concentration. During the follow- up period of >12 months, the patient remained asymptomatic. Her rheumatoid arthritis was treated with MTX monotherapy. Table Antimicrobial drug susceptibility test results for Mycobacterium haemophilum isolate from rheumatoid arthritis patient and other M. haemophilum isolates* This case illustrates the risk for infectious diseases during TNF-αA treatment. Rheumatoid arthritis can be treated effectively with MTX and TNFαA (6). Side effects of concern are infectious diseases, which prompt the need for screening for latent mycobacterial infection before commencing treatment (7). Despite screening, mycobacterial infections have been diagnosed after prolonged treatment in various patients (8). This case shows that not only M. tuberculosis but also nontuberculous mycobacteria (NTM) should be considered as possible pathogens. This possibility is of clinical importance because of the diagnostic challenges. Diagnosing NTM infections may require specific culture media and molecular assays. Under optimal conditions, cultures show growth of most NTM species (including M. haemophilum) within 2–3 weeks. NTM are less susceptible to antimicrobial drugs than M. tuberculosis. M. haemophilum is generally resistant in vitro to isoniazid, ethambutol, and rifampicin (Table), but no standardized susceptibility methods for M. haemophilum exist. Therefore, following current guidelines from the American Thoracic Society (ATS) is advisable for NTM infections (9). No specific recommendations exist for pulmonary M. haemophilum infections, but for disseminated M. haemophilum infections, the ATS recommends a multidrug regimen combining clarithromycin, rifampicin/rifabutin, and ciprofloxacin. Although no studies on treatment duration for M. haemophilum infections have been conducted, the ATS guidelines recommend treatment until cultures taken during therapy are negative for 1 year (9). Whether TNF-αA treatment can be continued during antimycobacterial treatment is a matter of debate in the absence of sufficient safety data (8). In active tuberculosis infection, treatment with TNF-αA is contraindicated before patients complete a standard regimen of antituberculosis therapy; no information is available for NTM disease (10). This case is presented especially to demonstrate the diagnostic challenges of NTM infections. For such cases, clinicians are advised to consult experts in the field of NTM infections.

In this study, we determined the efficacy of various dosing regimens for erythromycin and azithromycin against four pneumococci with different susceptibilities to penicillin in an in vitro pharmacokinetic model and in a mouse peritonitis model. The MIC was 0.03 μg/ml, and the 50% effective doses (determined after one dose) of both drugs were comparable for the four pneumococcal strains and were in the range of 1.83 to 6.22 mg/kg. Dosing experiments with mice, using regimens for azithromycin of one to eight doses/6 h, showed the one-dose regimen to give the best result; of the pharmacodynamic parameters tested (the maximum drug concentration in serum [ C max ], the times that the drug concentration in serum remained above the MIC and above the concentration required for maximum killing, and the area under the concentration time curve), C max was the best predictor of outcome. The bacterial counts in mouse blood or peritoneal fluid during the first 24 h after challenge were not correlated to survival of the mice. The serum concentration profiles obtained with mice for the different dosing regimens were simulated in the in vitro pharmacokinetic model. Here as well, the one-dose regimen of azithromycin showed the best result. However, the killing curves in vivo in mouse blood and peritoneal fluid and in the vitro pharmacokinetic model were not similar. The in vitro killing curves showed a decrease of 2 log 10 within 2 and 3 h for azithromycin and erythromycin, respectively, whereas the in vivo killing curves showed a bacteriostatic effect for both drugs. It is concluded that the results in terms of predictive pharmacodynamic parameters are comparable for the in vitro and in vivo models and that high initial concentrations of azithromycin favor a good outcome.

In the recent literature, cystatin C has been advocated as a new and more accurate estimate of glomerular filtration rate (GFR) (1). Cystatin C is a 13-kDa endogenous cysteine proteinase inhibitor produced by all nucleated cells at a constant rate and broken down completely in the renal tubuli (2). Cystatin C concentrations are independent of age and body weight, and there is no need for urine collection for clearance estimations. Furthermore, serum concentrations of cystatin C are not influenced by malignancy or inflammation. In contrast, the often-used serum creatinine concentration is supposedly influenced by dietary intake, renal tubular metabolism, age, and variations in muscle mass. There are also various analytical difficulties with the widely used Jaffe colorimetric assay for creatinine. A slight decrease in GFR has been found in patients with hypothyroidism, which improved significantly after treatment (3)(4)(5). We wondered whether cystatin C would also be a good marker of renal …

We read with interest the article by Villa and coworkers [1] advocating the use of cystatin C as a measure of glomerular filtration rate (GFR) in critically ill patients. However, we should like to draw attention to several flaws in this study. First, Villa and coworkers compared cystatin C with creatinine as a measure of GFR, using body surface corrected creatinine clearance as, what they call, a 'gold standard'. However, in the Discussion section of that report inulin and iothalamate clearances are mentioned as gold standards, but they were not used by these investigators. The use of body surface area corrected creatinine clearance is questionable in both obese and excessively lean individuals because the correlation between surface area and lean body mass may be lost. Both types of patients are frequently encountered in intensive care. Second, Villa and coworkers employ a cutoff of 80 ml/min to identify renal dysfunction, whereas a value of 50 ml/min is generally accepted [2]. This could have a major influence on the presented results. Third, patients with thyroid disorders or on corticosteroid therapy were excluded. Almost all patients with critical illness have low tri-iodothyronine values because of changes in thyroid hormone metabolism ('nonthyroidal illness'), thus making recognition of thyroid disorders problematic. Finally, we showed [3] that, in patients with thyroid dysfunction, cystatin C is not a suitable measure of GFR. In hypothyroidism creatinine levels are elevated but cystatin C levels are low, whereas in hyperthyroidism creatinine levels are low and cystatin C levels elevated. Taken together, we disagree with the authors that cystatin C could be used as a marker of GFR in intensive care patients.