Comparison of Three ß-Glucan Tests for the Diagnosis of Invasive Candidiasis in Intensive Care Units.

The (1→3)-ß-d-glucan (BDG) is a marker of invasive fungal infection that can be detected in serum by different commercial kits. In this study, we compared the performance of the Fungitell assay (FA), the Fungitell STAT assay (STAT), and the Wako ß-glucan test (WA) for the diagnosis of invasive candidiasis (IC) in the intensive care unit (ICU). Patients for whom at least one BDG testing was required for a clinical suspicion of IC were retrospectively enrolled. A total of 85 serum samples from 56 patients were tested by the three BDG tests. The rate of IC was 23% (13/56) with a predominance of noncandidemic (intra-abdominal) IC. STAT and WA results exhibited overall good correlation with those obtained by FA (Spearman's coefficient R = 0.90 and R = 0.89, respectively). For the recommended cutoffs of positivity, sensitivity and specificity for IC diagnosis were 77%/51% (FA, 80 pg/mL), 69%/53% (STAT, ratio 1.2), and 54%/65% (WA, 7 pg/mL), respectively. Optimal performance was obtained at 50 pg/mL (FA), ratio 1.3 (STAT), and 3.3 pg/mL (WA) with sensitivity/specificity of 85%/51%, 69%/57%, and 77%/58%, respectively. Overall, the three BDG tests showed comparable but limited performance in this setting with positive and negative predictive values for an estimated IC prevalence of 20% that were in the range of 30 to 35% and 85 to 95%, respectively.

Rational Use of Microbiological Tests in the Diagnosis of Central Nervous System Infections Using Restrictive Criteria: a Retrospective Study.

Central nervous infections, mostly represented by meningitis and encephalitis, remain a diagnostic challenge despite substantial advances in microbiological tools in recent years. Meanwhile, extensive microbiological workups, which often prove to be irrelevant retrospectively, continue to be processed on a large scale, therefore leading to unnecessary costs. The main goal of this study was to evaluate a systematic approach enabling more rational use of microbiological tools in the setting of community-acquired central nervous system infection diagnosis. In this single-center descriptive study, the modified Reller criteria were retrospectively extended to all neuropathogens tested in cerebrospinal fluid (CSF) samples with the FilmArray meningitis/encephalitis panel (BioFire Diagnostics, LLC) and bacterial culture. The inclusion period was 30 months. In total, 1,714 fluid (CSF) samples analyzed from 1,665 patients over 2 and a half years were reported. According to the retrospective application of the modified Reller criteria, microbiological testing was considered unnecessary in 544 CSF samples. Fifteen positive microbiological results were found among these samples, interpreted either as inherited chromosomally integrated human herpesvirus 6 (HHV-6), a false-positive result, or a true microbial detection without clinical relevance. No CNS infection case would have been missed if these analyses were not carried out, while about one-third of all meningitis/encephalitis multiplex PCR panels would have been saved. Our retrospective analysis suggests that the modified Reller criteria could be safely applied to all microbiological tests performed in CSF, thereby saving substantial costs. IMPORTANCE Microbiological testing in general and in the setting of central nervous system (CNS) infection in particular are often excessive, leading to superfluous laboratory work and costs. In this regard, restrictive criteria, named Reller criteria, have been developed to reduce unnecessary CSF herpes simplex virus 1 (HSV-1) PCR testing when suspecting encephalitis. These criteria were then adapted for increased safety to become the modified Reller criteria. This retrospective study aims at evaluating the safety of these criteria when applied to CSF microbiological testing in general, including multiplex PCR, direct examination, and bacterial culture. The postulate was that a CNS infection can be excluded if none of these criteria is present. According to our data set, no CNS infection would have been missed if the modified Reller criteria would have been applied to save microbiological tests. This study therefore proposes a simple way to reduce unnecessary microbiological testing in the context of CNS infection suspicion.

Causes of fever in Tanzanian adults attending outpatient clinics: a prospective cohort study.

OBJECTIVES: Exploring fever aetiologies improves patient management. Most febrile adults are outpatients, but all previous studies were conducted in inpatients. This study describes the spectrum of diseases in adults attending outpatient clinics in urban Tanzania. METHODS: We recruited consecutive adults with temperature ≥38°C in a prospective cohort study. We collected medical history and performed a clinical examination. We performed 27 364 microbiological diagnostic tests (rapid tests, serologies, cultures and molecular analyses) for a large range of pathogens on blood and nasopharyngeal samples. We based our diagnosis on predefined clinical and microbiological criteria. RESULTS: Of 519 individuals, 469 (89%) had a clinically or microbiologically documented infection and 128 (25%) were human immunodeficiency virus (HIV) -infected. We identified 643 diagnoses: 264 (41%) acute respiratory infections (36 (5.6%) pneumonia, 39 (6.1%) tuberculosis), 71 (11%) infections with another focus (31 (4.8%) gastrointestinal, 26 (4.0%) urogenital, 8 (1.2%) central nervous system) and 252 (39%) infections without focus (134 (21%) dengue, 30 (4.7%) malaria, 28 (4.4%) typhoid). Of the 519 individuals, 318 (61%), 179 (34%), 30 (6%) and 15 (3%), respectively, had a viral, bacterial, parasitic and fungal acute infection. HIV-infected individuals had more bacterial infections than HIV-negative (80/122 (66%) versus 100/391 (26%); p < 0.001). Patients with advanced HIV disease had a higher proportion of bacterial infections (55/76 (72%) if CD4 ≤200 cells/mm3 and 25/52 (48%) if CD4 >200 cells/mm3, p 0.02). CONCLUSIONS: Viral diseases caused most febrile episodes in adults attending outpatient clinics except in HIV-infected patients. HIV status and a low CD4 level strongly determined the need for antibiotics. Systematic HIV screening is essential to appropriately manage febrile patients.

Accuracy of comprehensive PCR analysis of nasopharyngeal and oropharyngeal swabs for CT-scan-confirmed pneumonia in elderly patients: a prospective cohort study.

OBJECTIVES: We aimed to assess the accuracy of PCR detection of viruses and bacteria on nasopharyngeal and oropharyngeal swabs (NPS) for the diagnosis of pneumonia in elderly individuals. METHODS: We included consecutive hospitalized elderly individuals suspected of having pneumonia. At inclusion, NPS were collected from all participants and tested by PCR for the presence of viral and bacterial respiratory pathogens (index test, defined as comprehensive molecular testing). Routine diagnostic tests (blood and sputum culture, urine antigen detection) were also performed. The reference standard was the presence of pneumonia on a low-dose CT scan as assessed by two independent expert radiologists. RESULTS: The diagnosis of pneumonia was confirmed in 127 of 199 (64%) included patients (mean age 83 years, community-acquired pneumonia in 105 (83%)). A pathogen was identified by comprehensive molecular testing in 114 patients (57%) and by routine methods in 22 (11%). Comprehensive molecular testing was positive for viruses in 62 patients (31%) and for bacteria in 73 (37%). The sensitivity and specificity were 61% (95% CI 53%-69%) and 50% (95% CI 39%-61%) for comprehensive molecular testing, and 14% (95% CI 82%-21%) and 94% (95% CI 86%-98%) for routine testing, respectively. Positive likelihood ratio was 2.55 for routine methods and 1.23 for comprehensive molecular testing. CONCLUSION: Comprehensive molecular testing of NPS increases the number of pathogens detected compared with routine methods, but results are poorly predictive of the presence of pneumonia. Hence, comprehensive molecular testing is unlikely to impact clinical decision-making (NCT02467192). CLINICAL TRIALS REGISTRATION: NCT02467192.

Low-conductance high selective inositol (1,4,5)-trisphosphate activated Ca2+ channels in plasma membrane of A431 carcinoma cells.

In many cells, activation of receptors coupled to PIP2 turnover results in Ca2+ release from the intracellular stores accompanied by Ca2+ influx across the PM. It is not well established yet whether Ca2+ influx is activated by IP3 or by an unknown signal generated upon Ca2+ store depletion. We report here a single-channel study of low-conductance IP3-activated channels of very high selectivity for Ca2+ in the PM of A431 carcinoma cells. The channels are strongly potential dependent and sensitive to [Ca2+]i within the physiological range. The data obtained argues for IP3 acting directly on plasma membrane Ca2+ channels.

[A new type of IP3-sensitive highly selective calcium channels of low conductance in the plasma membrane of carcinoma A 431 cells]. / Novyi tip IP3-chuvstvitel'nykh vysokoselektivnykh kal'tsievykh kanalov nizkoi provodimosti v plazmaticheskoi membrane kletok kartsinomy A 431.

Application of 0.2-15.0 mM inositol 1,4,5-trisphosphate (IP3) to excised plasma membrane patches from A 431 cells induced activity of low conductance channels that were highly selective for Ca2+ and Ba2+. With 100 mM Ca2+ or 105 mM Ba2+, the channel conductance was 1.1 pS for the minor conductance substrate. The dose response curve gave an apparent binding constant of 0.18 microM IP3. The channel open probability displayed a strong potential dependence: it decreased markedly upon depolarization, and the half-maximum value was achieved at 73 mV. The dependence of channel activity on the intracellular free Ca2+ concentration was bell shaped, but markedly different from that reported for endoplasmic IP3 receptor. The same channels were detected in intact cells upon application of calcium mobilizing reagents. The activity induced in cell attached mode disappeared after patch excision but could be resumed by application of IP3. The data obtained argue for IP3 acting directly on plasma membrane Ca2+ channels.

[Activation of mechanosensitive ion channels in plasma membrane of K562 cells]. / Aktivatsiia mekhanochuvstvitel'nykh ionnykh kanalov v plazmaticheskoi membrane kletok K562.

Patch clamp method in cell-attached configuration was used to search for mechanogated ion channels in plasma membrane of human myeloid leukemia K562 cells. A reversible activation of transmembrane currents in response to negative pressure applied to membrane patch was observed. Four types of mechanosensitive channels were identified in K562 cells: two main types were characterized with conductance values of 16 and 25 pS; while two others, showing higher conductance values (about 35 and 50 pS), were rarely met. In terms of gating, all channels described here could be assigned to the stretch-activated type. No inactivation of mechanosensitive channels at the sustained stimulation was observed. The activation of mechanosensitive channels in K562 cells was not dependent upon the presence of bivalent cations in the extracellular solution.

Epidemiology of viral respiratory infections in a tertiary care centre in the era of molecular diagnosis, Geneva, Switzerland, 2011-2012.

Few studies have examined the epidemiology of respiratory viral infections in large tertiary centres over more than one season in the era of molecular diagnosis. Respiratory clinical specimens received between 1 January 2011 and 31 December 2012 were analysed. Respiratory virus testing was performed using a large panel of real-time PCR or RT-PCR. Results were analysed according to sample type (upper versus lower respiratory tract) and age group. In all, 2996 (2469 (82.4%) upper; 527 (17.6%) lower) specimens were analysed. Overall positivity rate was 47.4% and 23.7% for upper and lower respiratory samples, respectively. The highest positivity rate was observed in patients under 18 years old (p <0.001); picornaviruses were the most frequent viruses detected over the year. Influenza virus, respiratory syncytial virus, human metapneumovirus and coronaviruses showed a seasonal peak during the winter season, while picornaviruses and adenoviruses were less frequently detected in these periods. Multiple viral infections were identified in 12% of positive cases and were significantly more frequent in children (p <0.001). In conclusion, we observed significant differences in viral infection rates and virus types among age groups, clinical sample types and seasons. Follow-up of viral detection over several seasons allows a better understanding of respiratory viral epidemiology.

Long-term hepatitis E viral load kinetics in an immunocompromised patient treated with ribavirin.

Hepatitis E virus (HEV) can cause chronic infections in immunocompromised hosts. Viral kinetics in plasma and stools are poorly understood, particularly during antiviral treatment. Prolonged faecal shedding may be a concern for transmission. We describe HEV kinetics in an immunocompromised patient with prolonged faecal shedding despite undetectable viraemia on ribavirin treatment.