Population bottlenecks can have major effects in the evolution of RNA viruses, but their possible influence in the evolution of DNA viruses is largely unknown. Genetic and biological variation of ...herpes simplex virus type 1 (HSV-1) has been studied by subjecting 23 biological clones of the virus to 10 plaque-to-plaque transfers. In contrast to large population passages, plaque transfers led to a decrease in replicative capacity of HSV-1. Two out of a total of 23 clones did not survive to the last transfer in 143 TK(-) cells. DNA from three genomic regions (DNA polymerase, glycoprotein gD and thymidine kinase) from the initial and passaged clones was sequenced. Nucleotide substitutions were detected in the TK and gD genes, but not in the DNA polymerase gene. Assuming a uniform distribution of mutations along the genome, the average rate of fixation of mutations was about five mutations per viral genome and plaque transfer. This value is comparable to the range of values calculated for RNA viruses. Four plaque-transferred populations lost neurovirulence for mice, as compared with the corresponding initial clones. LD(50) values obtained with the populations subjected to serial bottlenecks were 4- to 67-fold higher than for their parental clones. These results equate HSV-1 with RNA viruses regarding fitness decrease as a result of plaque-to-plaque transfers, and show that population bottlenecks can modify the pathogenic potential of HSV-1. Implications for the evolution of complex DNA viruses are discussed.
The development of sonication protocols over the last few years has improved the sensitivity of conventional cultures for the diagnosis of prosthetic-joint infection (PJI). However, the development ...of a new, specifically designed kit for the molecular diagnosis of PJI could provide a major improvement in this field.
Prostheses retrieved from patients who underwent implant removal from May 2014 to May 2015 were sent for culture, and processed according to a previously defined protocol that included sonication. Furthermore, 180 microlitres of sonication fluid were used to carry out the multiplex PCR test (Unyvero i60 system®). A comparison of the sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, was performed. The study was approved by the Clinical Research Ethics Committee.
The analysis included 88 prostheses from 68 patients (1.29 prostheses/patient). The type of prostheses studied were knee (n=55), total hip (n=26), partial hip (n=5), and shoulder (n=2). Twenty-nine patients were diagnosed with a PJI (15 delayed, 12 acute, and 2 haematogenous infections). In 24 cases, the result of the PCR was positive, all but 1 corresponding to patients with clinical criteria of PJI. Nine resistance mechanisms were detected from 5 samples. The Unyvero i60 system® showed slightly better results than traditional culture in terms of specificity and PPV.
The Unyvero i60 system® may play a role in rapid diagnosis of PJI, due to its high specificity and PPV. However, despite these results, cultures have to be performed to detect organisms not detected by the system.
El desarrollo de la sonicación durante los pasados años ha incrementado la sensibilidad de los cultivos convencionales para el diagnóstico de Infecciones de Prótesis Articulares (IPA). Sin embargo, el desarrollo de un nuevo kit, diseñado específicamente para el diagnóstico de las IPA podría suponer un avance significativo en este campo.
Todas las prótesis retiradas de pacientes entre mayo 2014 y mayo 2015 fueron enviadas para cultivo mediante un protocolo de procesamiento que incluye la sonicación del implante. Además, se emplearon 180 microlitros del líquido de sonicado en la realización de una PCR múltiple (Unyvero i60®). Se realizó una comparación de la sensibilidad, especificidad, valor predictivo positivo (VPP) y negativo (VPN). El estudio fue aprobado por el Comité de Ética en Investigación Clínica.
Se analizaron 88 prótesis de 68 pacientes (1,29 prótesis/paciente). Las prótesis estudiadas fueron rodillas (n=55), total de cadera (n=26), parcial de cadera (n=5), y hombro (n=2). Veintinueve pacientes fueron diagnosticados de IPA (15 crónicas, 12 agudas y 2 hematógenas). En 24 casos, el resultado de la PCR fue positivo, siendo todas menos 1 de estas de pacientes con criterios de IPA. Se detectaron además 9 mecanismos de resistencia en 5 muestras. El sistema Unyvero i60® mostró resultados ligeramente superiores al cultivo tanto en especificidad como en VPP.
El sistema Unyvero i60® puede tener un papel en el diagnóstico rápido de IPA debido a su elevada especificidad y VPP. Sin embargo, a pesar de estos resultados, debe realizarse cultivo para detectar organismos no detectados por el sistema.
Summary Objective To assess the current clinical features and determinants of outcome of Candida tropicalis bloodstream infection (BSI). Methods A population-based surveillance on Candida BSI was ...conducted from May 2010 to April 2011 in 29 Spanish hospitals. Antifungal susceptibility testing (EUCAST methodology) was centrally performed. The characteristics and outcome of C. tropicalis BSI episodes were compared with those due to other species. Results Fifty-nine out of 752 episodes (7.8%) were due to C. tropicalis (annual incidence: 0.62 cases per 100,000 population). Resistance to fluconazole and voriconazole was found in 23.2% and 26.8% of isolates. Breakthrough BSI occurred in 10.5% of episodes. Risk factors for C. tropicalis BSI were age (odds ratio OR: 1.01; P -value = 0.05), underlying leukaemia (OR: 4.77; P -value = 0.001) and chronic lung disease (OR: 2.62; P -value = 0.002). There were no differences in clinical failure (persistent BSI for ≥72 h after initiation of therapy and/or 30-day all-cause mortality) between C. tropicalis (39.6%) and non- C. tropicalis groups (45.6%). The appropriateness of antifungal therapy or the fluconazole MIC values had no significant impact on outcome, whereas early central venous catheter removal exerted a protective effect. Conclusions C. tropicalis BSI was associated with advanced age, haematological malignancy and respiratory comorbidity. We found no correlation between the unexpectedly high resistance rate to azoles observed and outcome.
Summary
The aim of the study was to analyse the epidemiology and prognosis of candidaemia in elderly patients. We performed a comparison of clinical presentation of candidaemia according to age and a ...study of hazard factors within a prospective programme performed in 29 hospitals. One hundred and seventy‐six episodes occurred in elderly patients (>75 years), 227 episodes in middle‐aged patients (61‐75 years) and 232 episodes in younger patients (16‐60 years). Central venous catheter, parenteral nutrition, neutropenia, immunosuppressive therapy and candidaemia caused by Candida parapsilosis were less frequent in elderly patients. These patients received inadequate antifungal therapy (57.3%) more frequently than middle‐aged and younger patients (40.5% P < .001). Mortality during the first week (20%) and 30 days (42%) was higher in elderly patients. The variables independently associated with mortality in elderly patients during the first 7 days were acute renal failure (OR: 2.64), Pitt score (OR: 1.57) and appropriate antifungal therapy (OR: 0.132). Primary candidaemia (OR: 2.93), acute renal failure (OR: 3.68), Pitt score (OR: 1.38), appropriate antifungal therapy (OR: 0.3) and early removal of the central catheter (OR: 0.47) were independently associated with 30‐day mortality.In conclussion, inadequate antifungal treatment is frequently prescribed to elderly patients with candidaemia and is related with early and late mortality.
We aimed to develop a simple prediction score to identify fluconazole non-susceptible (Flu-NS) candidaemia using simple clinical criteria. A derivation cohort was extracted from the CANDIPOP study, a ...prospective, multicentre, population-based surveillance programme on candidaemia conducted in 29 hospitals in Spain from April 2010 to May 2011. The score was validated with an external, multicentre cohort of adults with candidaemia in six tertiary hospitals in three countries. The prediction score was based on three variables selected by a logistic regression model together with the severity of disease. In total, 617 and 297 cases of candidaemia were included in the derivation and validation cohorts, respectively; of these, 134 (21.7%) and 57 (19.2%) were caused by Flu-NS strains. Factors independently associated with Flu-NS were transplant recipient status (adjusted odds ratio (AOR) 2.13; 95% CI 1.01–4.55; p 0.047), hospitalization in a unit with a high prevalence (≥15%) of Flu-NS strains (7.53; 4.68–12.10; p < 0.001), and previous azole therapy for at least 3 days (2.04; 1.16–3.62; p 0.014). The area under the receiver operating characteristics curve (AUC) was 0.76 (0.72–0.81), and using 2 points as the Flu-NS prediction score cut-off gave a sensitivity of 82.1%, a specificity of 65.6%, and a negative predictive value of 93%. The AUC in the validation cohort was 0.72 (95% CI 0.65–0.79). Hence, the Flu-NS prediction score helped to exclude Flu-NS Candida strains. This could improve the selection of empirical treatments for candidaemia in the future.
COVID-19 severity and progression are determined by several host and virological factors that may influence the final outcome of SARS-CoV-2-infected patients. The objective of this work was to ...determine a possible association between viral load, obtained from nasopharyngeal swabs, and the severity of the infection in a cohort of 448 SARS-CoV-2-infected patients from a hospital in Madrid during the first outbreak of the pandemic in Spain. To perform this, we clinically classified patients as mild, moderate and severe COVID-19 according to a number of clinical parameters such as hospitalization requirement, need of oxygen therapy, admission to intensive care units and/or death. Also, Ct values were determined using SARS-CoV-2-specific oligonucleotides directed to ORF1ab. Here we report a statistically significant association between viral load and disease severity, a high viral load being associated with worse clinical prognosis, independently of several previously identified risk factors such as age, sex, hypertension, cardiovascular disease, diabetes, obesity and lung disease (asthma and chronic obstructive pulmonary disease). The data presented here reinforce viral load as a potential biomarker for predicting disease severity in SARS-CoV-2-infected patients. It is also an important parameter in viral evolution since it relates to the numbers and types of variant genomes present in a viral population, a potential determinant of disease progression.
Cryptococcal meningoencephalitis (CM) is an uncommon entity, but remains a major cause of morbidity and mortality in patients with AIDS.
Review of CM cases in a university hospital. The diagnosis was ...determined by isolation of Cryptococcus neoformans in cerebrospinal fluid. Morbidity and mortality was assessed at 12 weeks (early mortality) and between 3 and 18 months after diagnosis (late mortality).
We analyzed 32 patients from 2,269 AIDS cases (1.41%). 10 patients between 1990-1996 and 22 between 1997-2014. Cryptococcal antigen in CSF was positive in all cases, with titers>1,024 in 19 patients (63%); this group had lower CD4+ counts (40 ± 33 vs. 139 ± 78 cel/μL) and greater disseminated involvement. After a first CM episode the relapse rate was 34%. Global mortality rate was 28% (9/32), much higher in the pre-HAART era.
CM morbidity and mortality is related to severe immunodeficiency, disseminated disease, high titers of antigen in CSF and delayed initiation of HAART.
Combined, simultaneous or sequential antifungal therapy has often been considered an appropriate option to improve the results obtained with monotherapy. Anidulafungin belongs to the echinocandin ...family, which has a different mechanism of action from the remaining antifungal agents, a characteristic that heralds a good chance of synergy with other groups. However, most of the data available on the efficacy of different combinations comes from animal models of infection, "in vitro" data and case reports, while data from controlled clinical trials are scarce. The available data are insufficient to allow us to conclude that the efficacy of combined therapy is significantly superior to that of monotherapy. However, the efficacy of combined therapy may be adequate for the treatment of severe invasive mycoses associated with high mortality rates, such as forms of aspergillosis that provoke central nervous system involvement, extensive pulmonary involvement, cavitated areas, or respiratory failure and infections caused by multiresistant fungi.
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