TRAUMATIC PULMONARY HERNIATION: A RARE CHEST TRAUMA MANIFESTATION.

Traumatic pulmonary hernia is an uncommon occurrence resulting from chest trauma, typically covered by the skin. Chest trauma may arise from penetrating or blunt mechanisms, with blunt trauma being more frequently observed. When lung herniation transpires, various symptoms such as chest pain, dyspnea, subcutaneous emphysema, bone crepitation, and hemoptysis (in cases of lung parenchymal damage) may manifest. We present the case of a 66-year-old woman suffering from chest pain and dyspnea after blunt chest trauma due to a fall induced by delirium following alcohol abuse.

Lack of evidence for the transmission of hepatitis E virus by coagulation factor concentrates based on seroprevalence data.

BACKGROUND: Whether hepatitis E virus (HEV) infection can be transmitted by coagulation factor concentrates remains unclear. OBJECTIVES: The HEV seroprevalence in blood donors and recipients of coagulation factor concentrates was compared to obtain evidence of whether a transmission of HEV by coagulation factor concentrates could occur. METHODS: Archived samples from whole blood donors and patients who had received coagulation factor concentrates were investigated for the presence of anti-HEV IgG by ELISA. Western blotting was used to confirm the positive samples that showed reactivity in the ELISA. RESULTS: Of 357 blood donors, 68 (19%) presented IgG antibodies against HEV. Two of 92 patients who had received coagulation factor concentrates (2·2%) and 1 of the 69 patients who had received plasma-derived products (1·5%) tested positive for anti-HEV IgG. The seroprevalence of HEV in the patient group was significantly lower (P = 0·038) than that in the donor group. The two positive patients were a 72-year-old man treated with plasma-derived products and a 5-year-old girl treated with a recombinant coagulation factor concentrate. CONCLUSION: HEV seroprevalence was significantly higher in the blood donors than in the patients with a history of coagulation factor concentrate administration. In one of two patients with detectable anti-HEV IgG antibodies, the coagulation factor concentrate was not the probable source of infection. Our data suggest that HEV is efficiently inactivated during the manufacturing process of coagulation factor concentrates. Thus, testing for the presence of HEV RNA in plasma donated for the preparation of coagulation factor concentrates may not be necessary.

Look-back study on recipients of Parvovirus B19 (B19V) DNA-positive blood components.

BACKGROUND AND OBJECTIVES: To assess the relevance of Parvovirus B19 (B19V) DNA at low to intermediate concentrations in blood donors for the recipients of their blood components. MATERIAL AND METHODS: We studied recipients of B19V DNA-positive blood components [red blood cell concentrates (RBCs), pooled platelet concentrates and fresh frozen plasma]. This included archived pretransfusion samples as well as follow-up samples investigated by ELISA or NAT and genome sequence analysis. RESULTS: In 132 out of 424 recipients, we could detect no anti-B19V IgG before transfusion. In 67 out of 132 sero-negative recipients, a follow-up sample was available. Sixty-five of these received blood components from donors with <10(4) IU B19V DNA/ml plasma and had no evidence of transfusion-transmitted (TT)-B19V infection. Homology in genome sequences in donor and recipient provided evidence for a TT-B19V infection in two recipients. Both patients received RBC containing 3.4 × 10(6) and 1.8 × 10(4) IU B19V DNA/ml plasma, respectively. The anti-B19V IgG titres in the donors were 2 and 76 IU/ml plasma, respectively. The antibodies in the second donor were directed against capsid proteins and are thus considered as potential neutralizing antibodies. CONCLUSIONS: TT-B19V infections through blood components with low (<10(4) IU/ml plasma) B19V DNA concentrations did not occur in our study. One of the TT-B19V infections occurred from RBC with intermediate B19V DNA concentration despite the presence of potential neutralizing antibodies in the donor, but its clinical significance was low.

Persistence of Parvovirus B19 (B19V) DNA and humoral immune response in B19V-infected blood donors.

BACKGROUND AND OBJECTIVES: Parvovirus B19 (B19V) DNA seems to persist in the plasma of B19V-infected blood donors. The relevance of this for recipients of single-donor blood components is yet unclear. MATERIAL AND METHODS: We studied serial archive and follow-up samples from 75 B19V-infected blood donors to obtain more data about the duration and degree of viraemia and the presence of IgG and IgM anti-B19V. IgG antibodies were further characterized by Western blot analysis in 29 donors. RESULTS: In 411 B19V DNA-positive samples collected, we found high concentrations (>10(6) IU B19V DNA/ml plasma) in five. B19V DNA persisted for a mean of 21·5 months (range: 2·3-52·4; 95% confidence interval, 19·1-23·9 months) in all donors. Only 15 such samples had either no or low-titre IgG anti-B19V. IgG antibodies were predominantly directed against epitopes on the minor capsid protein VP1, thus probably of neutralizing type with high avidity. IgM anti-B19V was detectable in 9/13 samples with high DNA concentrations. CONCLUSIONS: The vast majority of single-donor blood components with detectable B19V DNA are probably not infectious for their recipients because DNA is at only low levels and the donors also have potentially neutralizing antibodies with high avidity. Anti-B19V IgM testing does not identify every donation with high B19V DNA concentrations, but, in addition to B19V NAT testing, donors with persistent IgG anti-B19V might be considered 'B19V-safe' for single-donor blood components.

Comparison of the two fully automated anti-HCMV IgG assays: Abbott Architect CMV IgG assay and Biotest anti-HCMV recombinant IgG ELISA.

OBJECTIVE AND BACKGROUND: To assess the performance characteristics of two fully automated human cytomegalovirus (HCMV) antibody tests. MATERIALS AND METHODS: Samples from negatively or not pre-screened blood donors were tested by the Biotest anti-HCMV recombinant IgG enzyme-linked immunosorbent assay (ELISA) in comparison to the Abbott Architect CMV IgG assay [chemiluminescent microparticle immunoassay (CMIA)]. For clarification, samples with discordant results between both assays were subjected to supplemental testing for anti-HCMV IgG, IgM and HCMV DNA in plasma. RESULTS: From 4938 samples tested, 362 delivered positive results in both assays (7.3%). 91 (1.8%) samples were discordant. Of 43 (two not further tested) samples positive only by ELISA, 41 were false positive, one true positive and one indeterminate. Of 45 (one not further tested) samples positive only by CMIA, 20 were false positive, 9 indeterminate and 16 true positive. Anti-HCMV IgM and HCMV DNA testing from the plasma were negative in indeterminate samples. Considering the results of supplemental testing, the CMIA achieved altogether better results concerning resolved sensitivity, resolved specificity as well as negative predictive value. Both assays had an inferior positive predictive value, with a better result for CMIA. CONCLUSION: Overall, the performance characteristics of the CMIA were better than those of the ELISA. Owing to the inferior positive predictive value, positive test results require confirmation if blood products from donors with remote HCMV infection should be administered.

Preanalytical stability of HIV-1 and HCV RNA: impact of storage and plasma separation from cells on blood donation testing by NAT.

BACKGROUND: The aim of this study was to evaluate the optimal preanalytical conditions prior to nucleic acid amplification technology (NAT) for human immunodeficiency virus-1 (HIV-1) or Hepatitis C virus (HCV) RNA in pools of 96 plasma specimens with regard to storage temperature, time and plasma separation in a blood donation environment. STUDY DESIGN AND METHODS: Changes in viral nucleic acid concentration of HIV-1 and HCV were observed for 5 days according to the Paul-Ehrlich-Institute's (PEI) guidelines that demand 95%-detection limit of at least 10 000 IU mL(-1) for HIV-1 RNA and 5000 IU mL(-1) for HCV RNA within a single donor blood specimen. Ninety-five per cent detection limits of HIV-1 RNA over 3 days after storage at either 5 or 21 °C were evaluated by using standardised HIV-1 RNA-positive plasma. RESULTS: HCV RNA in whole blood samples proved to be more stable than HIV-1 RNA. Whole blood storage at 21 °C was shown to decrease the detectability of HIV-1 RNA even after only 18 h. Plasma samples once used for NAT at time 18 h did not alter viral stability up to 48 h after donation. Ninety-five per cent detection limits of HIV-1 RNA were securely below 10 000 IU mL(-1) for 24 h after whole blood storage at 5 °C. CONCLUSIONS: These results may lead to a discussion around the most suitable preanalytical conditions in blood donation environments. Contrary to the current PEI guidelines that allow storage of whole blood specimens up to 18 h at 21 °C, these results suggest that immediate storage in a 5 °C container after blood donation is more suitable and would permit storage of whole blood up to 24 h prior to the separation of plasma from cells.

The natural course of primary cytomegalovirus infection in blood donors.

BACKGROUND AND OBJECTIVES: As cytomegalovirus (CMV) DNA is frequently detectable in the plasma of recently infected sero-positive blood donors, information concerning primary CMV infection is important for the identification of possibly infectious donors. MATERIALS AND METHODS: Monitoring of 17 982 donors for CMV antibodies and DNA in plasma identified 14 subjects with ongoing primary CMV infection. Thirteen donors were interrogated for possible sources of infection and CMV-related symptoms, and monitored for CMV antigens, CMV DNA in plasma, leucocytes and urine, course of IgG and IgM antibodies as well as markers of systemic infection and parameters of organ function. RESULTS: CMV antigens and DNA were detectable in peripheral blood for up to 54 and 269 days respectively. Clearance of CMV DNA from blood correlated with clearance of IgM antibodies, development of IgG antibodies against the membrane glycoprotein gB and development of high avidity IgG antibodies. Eighty-five percent of subjects with primary CMV infection, but even 69% of matched controls reported possibly CMV-related symptoms. Sixty-two and 23%, respectively, had contact with possible sources of infection. One donor developed a febrile illness accompanied by increased levels of CMV DNA in peripheral blood 2 to 3 weeks after seroconversion. In other donors, neither markers of systemic infection nor parameters of organ function correlated with the course of CMV DNA and antigens. CONCLUSION: Potentially infectious donors can be identified by measuring CMV DNA, IgM antibodies or avidity of IgG antibodies. Alternatively, blood products donated during the first year after seroconversion should not be used for immunocompromised patients.

Detection of herpes simplex virus DNA in plasma of patients with primary but not with recurrent infection: implications for transfusion medicine?

Among the family of herpes viruses, only cytomegalovirus (CMV) and, to a lesser extent, human herpes virus 8 (HHV-8) are of relevance in transfusion medicine. Due to neutropism, herpes simplex viruses (HSV) types 1 and 2 are considered to be of minor relevance. However, several reports gave evidence that a HSV DNAemia might occur and HSV could therefore be transmissible by blood products. The aim of our study was to collect data about prevalence of HSV antibodies among blood donors and to clarify whether HSV DNAemia is possible. HSV antibody states of 653 blood donors were investigated. Blood specimens of 46 patients with primary and recurrent HSV infection were tested for HSV-1 and HSV-2 DNA using TaqMan polymerase chain reaction. In 505 of the 653 blood donors HSV antibodies were detectable, most of which were HSV-1 antibodies. HSV DNA was detected in plasma, but not in peripheral blood mononuclear cells (PBMCs) of seven rather seriously ill patients with primary herpes genitalis. No HSV viraemia was detectable in otherwise healthy patients with recurrent herpes labialis. Thus, HSV DNAemia is possible, but seems to be limited to primary infections and could not be detected in the recurrent infection. Therefore, blood donors with primary herpes infection should be deferred from donation. Blood donors with recurrent HSV infection are probably not at risk of transmitting HSV, but further studies are necessary to prove this hypothesis. Detection of HSV DNA in PBMCs as described formerly could not be confirmed by this study.

Fractal conductance fluctuations of classical origin.

In mesoscopic systems, conductance fluctuations are a sensitive probe of electron dynamics and chaotic phenomena. We show that the conductance of a purely classical chaotic system, with either fully chaotic or mixed phase space, generically exhibits fractal conductance fluctuations unrelated to quantum interference. This might explain the unexpected dependence of the fractal dimension of the conductance curves on the (quantum) phase breaking length observed in experiments on semiconductor quantum dots.

Multi-organ affecting CMV-associated cryoglobulinemic vasculitis.

We report on a 67-year-old female patient who was admitted to our intensive care unit with acute renal failure and severe hypoxemia. Transiently, the patient had to be treated with kidney replacement therapies and artificial ventilation. The actual illness started with general weakness, recurrent bloody diarrhea and intermittent dermatitis of the lower legs. Skin symptoms were initially observed 2 years before the actual clinical findings. The bloody diarrhea was attributed to an inflammatory stenosis of the sigma. The life-threatening clinical aggravation was due to diffuse alveolar hemorrhage and alveolitis. In the search for the cause of the systemic disease, both a monoclonal y-globulinemia, causing a cryoglobulinemia type II and an acute cytomegalovirus infection were diagnosed. Additionally, the course of the disease was complicated by a secondary antibody deficiency as well as an endocarditis of the aortic valve caused by Enterococcus faecium. A cryoglobulinemic vasculitis type II was histologically found in biopsy specimen of the kidney. Thus, the present case reports on a coincidence of a monoclonal gammopathy causing a cryoglobulinemia type II with extensive organ involvement and a florid CMV infection. We hypothesize that the CMV infection has triggered the cryoglobulinemia and its particular severe organ involvement.

Dynamical phase diagram of Gaussian wave packets in optical lattices.

We study the dynamics of self-trapping in Bose-Einstein condensates (BECs) loaded in deep optical lattices with Gaussian initial conditions, when the dynamics is well described by the discrete nonlinear Schrödinger equation (DNLSE). In the literature an approximate dynamical phase diagram based on a variational approach was introduced to distinguish different dynamical regimes: diffusion, self-trapping, and moving breathers. However, we find that the actual DNLSE dynamics shows a completely different diagram than the variational prediction. We calculate numerically a detailed dynamical phase diagram accurately describing the different dynamical regimes. It exhibits a complex structure that can readily be tested in current experiments in BECs in optical lattices and in optical waveguide arrays. Moreover, we derive an explicit theoretical estimate for the transition to self-trapping in excellent agreement with our numerical findings, which may be a valuable guide as well for future studies on a quantum dynamical phase diagram based on the Bose-Hubbard Hamiltonian.

Circulating hepatitis B virus nucleic acids in chronic infection : representation of differently polyadenylated viral transcripts during progression to nonreplicative stages.

PURPOSE: Beside the established maturation of hepatitis B virus (HBV) transcripts at a polyadenylation signal downstream of the HBV x protein open reading frame, maturation at an internal polyadenylation signal has been observed in the chronically infected liver. In the present study, it was the aim to identify the respective circulating full-length and truncated transcripts in plasma/serum of carriers. EXPERIMENTAL DESIGN: Nucleic acids extracted from sera were analyzed using established PCR and reverse transcription-PCR procedures targeted to HBV x protein gene regions. Amplification products were cloned and sequenced. RESULTS: Base substitution patterns were determined, which indicated infection stages advanced to different degrees regardless of the transcript type analyzed. HBV full-length RNA (fRNA) showed a high correlation with hepatitis B e antigen and viral DNA, indicative for a replicative infection. In contrast, truncated RNA (trRNA) appeared to be independent of hepatitis B e antigen and showed only a weak association with circulating viral DNA. No correlation was observed between the levels of trRNA and the apparent liver damage as reflected by alanine transaminase levels. An age-dependent representation of fRNA and trRNA was observed: fRNA decreased progressively to low levels, whereas trRNA remained at comparably high values. trRNA and RNA not polyadenylated at either of the two polyadenylation signals were detected even in the absence of any other conventional HBV seromarker, including viral DNA. This was shown for patients with cryptogenic cirrhosis and hepatitis C virus carriers. CONCLUSIONS: The identification of HBV RNA in human serum has a diagnostic potential for apparent and for inapparent infection stages.

Association between clinical disease activity and Epstein-Barr virus reactivation in MS.

OBJECTIVE: To assess the potential significance of Epstein-Barr virus (EBV) reactivation in disease activity in MS patients. METHODS: The prevalence of antibodies against herpes simplex virus type 1 (HSV-1), HSV-2, EBV, and cytomegalovirus was determined in a group of 108 MS patients and in 163 healthy control subjects. Sera were analyzed using combinations of novel assay systems employing highly purified viral and recombinant antigens. In addition, PCR for the detection of EBV DNA was performed in serial samples. RESULTS: In contrast to the control populations, antibodies against EBV were present in 100% of MS patients. Among the tested human herpesviruses, this high extent of seropositivity was only found for EBV. Primary infection was found exclusively in the control group (3.7%), whereas serologic evidence of EBV reactivation was seen in MS patients (13. 9%) as well as control subjects (17.2%). There was no temporal coincidence between EBV reactivation and disease activity in MS patients. However, in 19 patients followed monthly for 1 year, active viral replication as measured by increased immunoglobulin (Ig) M and IgA responses to EBV early antigens (p54 + p138) and positive serum DNA was seen in 72.7% of patients with exacerbations during the study period and in none of the patients with clinically stable disease. CONCLUSIONS: The results demonstrate an association between EBV reactivation and disease activity in MS patients over time, and suggest that EBV might play an indirect role in MS as an activator of the underlying disease process.

Quantification of platelet-associated IgG for differential diagnosis of patients with thrombocytopenia.

Immune thrombocytopenia is due to platelet destruction by circulating glycoprotein-specific antibodies and is found in various disorders. Methods for the detection of platelet-associated IgG (PAIgG) are generally sensitive but unspecific, whereas glycoprotein-specific assays are highly specific but less sensitive. Usefully, a sensitive screening method for PAIgG detection would also provide information for differential diagnosis. We developed a quantitative direct Platelet Immunofluorescence Test (PIFT) by flow cytometry and studied 79 thrombocytopenic patients with immune thrombocytopenia and other disorders. The sensitivity of the assay was 94%, its specificity 66% for the detection of a clinically obvious immune thrombocytopenia. PAIgG levels of patients with immune thrombocytopenia differed significantly from those of other patients with low platelet counts (p <0.001). The quantitative PIFT proved to be a sensitive method for PAIgG detection and should therefore be used as a screening method. In addition, it could be helpful for differential diagnosis in marked thrombocytopenia where a MAIPA is not feasible.

Altered prevalence and reactivity of anti-Epstein-Barr virus antibodies in patients with multiple sclerosis.

In this study, the prevalence and reactivity of anti-Epstein-Barr virus (EBV) antibodies were investigated in 107 patients with multiple sclerosis (MS) in comparison to age- and gender-matched healthy controls from a north German state. We found a significant 100% EBV-seropositivity and a significant lack of primary EBV infections in the MS group, indicating that all MS patients are infected with EBV before the development of MS. Although there were no differences in reactivities of EBV-specific anti-early antigen (EA)-immunoglobulin G (IgG), -IgM, and -IgA antibodies between each group, MS patients had significant lower anti-Epstein-Barr nuclear antigen (EBNA)1-IgG antibody titers as a possible serological sign for a defective control of the persistent latent EBV carrier state and EBV reactivations. Longitudinal studies of MS patients are necessary to further determine the implications of EBV reactivations on the course and disease activity of MS.

Metal-binding proteins as metal pollution indicators.

The fact that metal-binding proteins are a consequence of elevated metal concentration in organisms is well known. What has been overlooked is that the presence of these proteins provides a unique opportunity to reformulate the criteria of metal pollution. The detoxification effect of metal-binding proteins in animals from polluted areas has been cited, but there have been only very few studies relating metal-binding proteins to pollution. This lack is due partly to the design of most experiments, which were aimed at isolation of metal-binding proteins and hence were of too short duration to allow for correlation to adverse physiological effects on the organism. In this study metal-binding proteins were isolated and characterized from five different marine animals (rock lobster, Jasus lalandii; hermit crab, Diogenes brevirostris; sandshrimp, Palaemon pacificus; black mussel, Choromytilus meridionalis; and limpet, Patella granularis). These animals were kept under identical metal-enriched conditions, hence eliminating differences in method and seasons. The study animals belonged to different phyla; varied in size, mass, age, behavior, food requirements and life stages; and accumulated metals at different rates. It is possible to link unseasonal moulting in crustacea, a known physiological effect due to a metal-enriched environment, to the production of the metal-binding protein without evidence of obvious metal body burden. Thus a new concept of pollution is defined: the presence of metal-binding proteins confirms toxic metal pollution. This concept was then tested under field conditions in the whelk Bullia digitalis and in metal-enriched grass.

Evaluation of newly developed microparticle enzyme immunoassays for the detection of HCV antibodies.

The newly developed anti-HCV assays AxSYM HCV version 3.0 and IMx HCV version 3.0 were evaluated with regard to their precision, sensitivity and specificity in comparison to the HCV EIA 3.0 (Abbott GmbH, Wiesbaden, Germany). Precision testing was undertaken using five positive controls with different anti-HCV levels for each assay. Specificity was estimated by testing 4383 blood donor specimens. The supplemental assay Matrix HCV 2.0 (Abbott GmbH, Wiesbaden, Germany) was used to confirm repeatedly reactive results. Samples which had been found to be positive or indeterminate by Matrix HCV 2.0 were tested by qualitative polymerase chain reaction after reverse transcription (RT-PCR, Amplicor HCV test, Roche Diagnostic Systems, Basel, Switzerland). To determine sensitivity, 20 commercially available seroconversion panels were tested. Based on supplemental testing, the apparent specificities of AxSYM HCV version 3.0, IMx HCV version 3.0 and HCV EIA 3.0 were estimated to be 99.84, 99.98 and 99.80%, respectively. In seroconversion panel testing, AxSYM and IMx HCV version 3.0 detected seroconversion in up to 12/20 panels earlier and in up to 1/20 cases later than the comparison EIA. The highest sensitivity was shown in AxSYM HCV version 3.0, followed by IMx HCV version 3.0 and HCV EIA 3.0. Based on the improved seroconversion sensitivity and specificity, the AxSYM and IMx HCV version 3.0 assays appear to be suitable for detecting HCV antibodies in blood donor testing and other routine laboratory assessments.

Lack of evidence for Marek's disease virus genomic sequences in leukocyte DNA from multiple sclerosis patients in Germany.

Herpes viruses have repeatedly been associated with the etiology of multiple sclerosis (MS). In the course of investigations on a cluster of MS patients in Key West, Florida, it was suggested that Marek's disease virus (MDV), a cell-associated avian herpes virus, might be involved in the pathogenesis of the disease. The aim of our study was to investigate 107 well-defined MS patients with regard to latent MDV infection. Using a highly-sensitive polymerase chain reaction technique, we did not find MDV-related sequences in leukocyte DNA of any of the patients. The results of our study do not suggest an implication of MDV in the pathogenesis of MS.

Fractal dynamics in chaotic quantum transport.

Despite several experiments on chaotic quantum transport in two-dimensional systems such as semiconductor quantum dots, corresponding quantum simulations within a real-space model have been out of reach so far. Here we carry out quantum transport calculations in real space and real time for a two-dimensional stadium cavity that shows chaotic dynamics. By applying a large set of magnetic fields we obtain a complete picture of magnetoconductance that indicates fractal scaling. In the calculations of the fractality we use detrended fluctuation analysis-a widely used method in time-series analysis-and show its usefulness in the interpretation of the conductance curves. Comparison with a standard method to extract the fractal dimension leads to consistent results that in turn qualitatively agree with the previous experimental data.

The Importance of Accurate Microorganism Identification in Microbial Challenge Tests of Membrane Filters. Part II. The Comparison of Hydrogenophaga pseudoflava ATTC 33668 and Curvibacter sp. ATCC 700892 by Microbial Challenge Tests with Membrane Filters.

The ASTM 838-05 standard describes a bacteria challenge test procedure based on Brevundimonas diminuta (ATCC 19146) to verify a 0.2 µm rated sterilizing-grade filter. For process validation procedures a correct identification of the challenge organism is essential. The test strain ATCC 700892 repeatedly used for microbial challenge tests was incorrectly named Hydrogenophaga pseudoflava but is phylogenetically linked to the genus Curvibacter, as shown in Part I of this series. Based on these studies the misconception was consolidated that Hydrogenophaga pseudoflava, a widely isolated microorganism also found in biopharmaceutical production settings, is able to penetrate 0.2 µm rated filters. Here we show that the bacteria challenge test results of the strains Curvibacter sp. ATCC 700892 and Hydrogenophaga pseudoflava ATCC 33668 are different. In previous challenge tests analytical filter membranes were used; these do not represent the process scenarios within the sterilizing filtration in industrial processes. To represent process systems, the study data presented were determined with 10" filter cartridge elements. The strain Hydrogenophaga pseudoflava ATCC 33668 is completely retained by 0.2 µm and 0.1 µm rated filters. Depending on the different 0.2 µm filter material there are different retention rates of the strain Curvibacter sp. ATCC 700892; only the 0.1 µm rated filters showed consistent complete retention. However, up to date the genus Curvibacter seems to be of low relevance within biopharmaceutical production settings. LAY ABSTRACT: Bacteria challenge tests are used to determine the retention performance of sterilizing-grade filters. The model organism used for bacteria challenge tests and the verification of a 0.2 µm rated sterilizing-grade filter is Brevundimonas diminuta. In previous studies another proposed, model organism used for challenge tests was incorrectly labelled as Hydrogenophaga pseudoflava. Given the predefined retention characteristics, this mislabelled organism was recommended to be included in bacteria challenge studies. However, the herein presented testing demonstrated that the organism is actually phylogenetically affiliated to the genus Curvibacter and not to the strain Hydrogenophaga pseudoflava ATCC 33668. In this report, we demonstrate that the retention of the strain Hydrogenophaga pseudoflava ATCC 33668 with 0.1 µm and 0.2 µm rated filters is comparable to the retention of Brevundimonas diminuta ATCC 19146.