Roberto Alonso - Academia.edu (original) (raw)
Papers by Roberto Alonso
Frontiers in Cellular and Infection Microbiology
IntroductionSince the COVID-19 outbreak, specific mRNA-based anti-SARS-CoV-2 vaccines have been d... more IntroductionSince the COVID-19 outbreak, specific mRNA-based anti-SARS-CoV-2 vaccines have been developed and distributed worldwide. Because this is the first time that mRNA vaccines have been used, there are several questions regarding their capacity to confer immunity and the durability of the specific anti-SARS-CoV-2 response. Therefore, the objective of this study was to recruit a large cohort of healthcare workers from the Gregorio Marañón Hospital vaccinated with the mRNA-1273 or BNT126b2 vaccines and to follow-up on IgG anti-RBD levels at 8 months post-vaccination.MethodsWe recruited 4,970 volunteers and measured IgG anti-RBD antibodies on days 30 and 240 post-vaccination.ResultsWe observed that both vaccines induced high levels of antibodies on day 30, while a drastic wane was observed on day 240, where mRNA-1273 vaccinated induced higher levels than BNT162b2. Stratifying by vaccine type, age, gender, and comorbidities, we identified that older mRNA-1273-vaccinated volunteer...
Biomedicines
Vaccination against SARS-CoV-2 has become the main method of reducing mortality and severity of C... more Vaccination against SARS-CoV-2 has become the main method of reducing mortality and severity of COVID-19. This work aims to study the evolution of the cellular and humoral responses conferred by two mRNA vaccines after two doses against SARS-CoV-2. On days 30 and 240 after the second dose of both vaccines, the anti-S antibodies in plasma were evaluated from 82 volunteers vaccinated with BNT162b2 and 68 vaccinated with mRNA-1273. Peripheral blood was stimulated with peptides encompassing the entire SARS-CoV-2 Spike sequence. IgG Anti-S antibodies (humoral) were quantified on plasma, and inflammatory cytokines (cellular) were measured after stimulation. We observed a higher response (both humoral and cellular) with the mRNA-1273 vaccine. Stratifying by age and gender, differences between vaccines were observed, especially in women under 48 and men over 48 years old. Therefore, this work could help to set up a vaccination strategy that could be applied to confer maximum immunity.
Journal of Fungi, 2022
There is scarce information on the actual incidence of candidemia in COVID-19 patients. In additi... more There is scarce information on the actual incidence of candidemia in COVID-19 patients. In addition, comparative studies of candidemia episodes in COVID-19 and non-COVID-19 patients are heterogeneous. Here, we assessed the real incidence, epidemiology, and etiology of candidemia in COVID-19 patients, and compared them with those without COVID-19 (2020 vs. 2019 and 2020, respectively). We also genotyped all C. albicans, C. parapsilosis, and C. tropicalis isolates (n = 88), causing candidemia in both groups, providing for the first time a genotypic characterization of isolates gathered in patients with either COVID-19 or non-COVID-19. Incidence of candidemia was higher in patients with COVID-19 than non-COVID-19 (4.73 vs. 0.85 per 1000 admissions; 3.22 vs. 1.14 per 10,000 days of stay). No substantial intergroup differences were found, including mortality. Genotyping proved the presence of a low number of patients involved in clusters, allowing us to rule out rampant patient-to-patien...
Journal of Fungi, 2021
The implementation of 1,3 β-d-glucan (BDG) has been proposed as a diagnostic tool in antifungal s... more The implementation of 1,3 β-d-glucan (BDG) has been proposed as a diagnostic tool in antifungal stewardship programs (ASPs). We aimed to analyze the influence of serum BDG in an ASP for oncologic patients and solid organ transplant (SOT) recipients. We conducted a pre–post study. In the initial period (PRE), the ASP was based on bedside advice, and this was complemented with BDG in the post-period (POST). Performance parameters of the BDG assay were determined. Antifungal (AF) use adequacy was evaluated using a point score. Clinical outcomes and AF costs were also compared before and after the intervention. Overall, 85 patients were included in the PRE-period and 112 in the POST-period. Probable or proven fungal infections were similar in both groups (54.1% vs. 57.1%; p = 0.67). The determination of BDG contributed to improved management in 75 of 112 patients (66.9%). The AF adequacy score improved in the POST-period (mean 7.75 vs. 9.29; p < 0.001). Median days of empiric AF trea...
Journal of Clinical Microbiology, 1999
JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML),... more JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a central nervous system infection that mainly affects AIDS patients. The extensive application of highly active antiretroviral therapy (HAART) is leading to the appearance of “long-term” survival PML patients. A reliable and feasible qualitative-quantitative test for both the detection of JCV and follow-up of its viral burden in this emerging group of patients is clearly required. With this aim, a dual qualitative-quantitative nested PCR is presented in this study for the analysis of JCV DNA in cerebrospinal fluid (CSF). Two newly designed internal controls, one competitive and the other noncompetitive, have been constructed to adapt this PCR to either measure the JCV burden or to allow a highly confident determination of JCV presence or clearance. The analytical sensitivity of the technique allows the detection of 0.01 fg (three genomes) of JCV DNA. Its qualitative application has bee...
Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology, 2018
The Architect HIV Ag/Ab Combo Assay, a fourth-generation ELISA, has proven to be highly reliable ... more The Architect HIV Ag/Ab Combo Assay, a fourth-generation ELISA, has proven to be highly reliable for the diagnosis of HIV infection. However, its high sensitivity may lead to false-positive results. To evaluate the diagnostic performance of Architect in a low-prevalence population and to assess the role of the sample-to-cutoff ratio (S/CO) in reducing the frequency of false-positive results. We conducted a retrospective study of samples analyzed by Architect between January 2015 and June 2017. Positive samples were confirmed by immunoblot (RIBA) or nucleic acid amplification tests (NAATs). Different S/CO thresholds (1, 2.5, 10, 25, and 100) were analyzed to determine sensitivity, specificity, and negative and positive predictive values (NPV, PPV). ROC analysis was used to determine the optimal S/CO. A total of 69,471 samples were analyzed. 709 (1.02%) were positive by Architect. Of these, 63 (8.89%) were false-positive results. Most of them (93.65%) were in samples with S/CO < 10...
Annals of Pharmacotherapy, 2017
Background: Evidence about the use of dolutegravir (DTG) and rilpivirine (RPV) as an antiretrovir... more Background: Evidence about the use of dolutegravir (DTG) and rilpivirine (RPV) as an antiretroviral therapy (ART) in treatment-experienced patients is scarce. Objective: To explore the effectiveness, safety, and costs of switching to a DTG plus RPV regimen in this population. Methods: This observational, prospective study included all treatment-experienced patients who switched to DTG plus RPV between November 2014 and July 2016. Patients were excluded if resistance mutations to integrase inhibitors or RPV were found. The effectiveness endpoint was the proportion of patients who achieved virological suppression (viral load [VL] <50 copies/mL) at week 48 (W48). Safety (incidence of adverse events leading to discontinuation and laboratory abnormalities), adherence, and costs were analyzed. Results: A total of 35 patients were included, and 91.4% were virologically suppressed at baseline. Patients were treated with ART for a median of 14 years (interquartile range = 7-20). At W48, 9...
Enfermedades infecciosas y microbiologia clinica, Mar 25, 2017
Detection of hepatitis C virus (HCV) RNA and the HCV core antigen assay (HCV-Ag) are reliable tec... more Detection of hepatitis C virus (HCV) RNA and the HCV core antigen assay (HCV-Ag) are reliable techniques for the diagnosis of active and chronic HCV infection. Our aim was to evaluate the HCV-Ag assay as an alternative to quantification of HVC RNA. A comparison was made of the sensitivity and specificity of an HCV-Ag assay (204 serum samples) with those of a PCR assay, and the correlation between the two techniques was determined. The sensitivity and specificity of HCV-Ag was 76.6% and 100%, respectively. Both assays were extremely well correlated (Pearson coefficient=0.951). The formula (LogCV=1.15*LogAg+2.26) was obtained to calculate the viral load by PCR from HCV-Ag values. HCV-Ag was unable to detect viral loads below 5000IU/mL. Although the HCV-Ag assay was less sensitive than the PCR assay, the correlation between both assays was excellent. HCV-Ag can be useful as a first step in the diagnosis of acute or chronic HCV infection and in emergency situations.
Transplant Infectious Disease, 2016
Background: Immunoglobulin G (IgG) hypogammaglobulinemia (HGG) is a risk factor for development o... more Background: Immunoglobulin G (IgG) hypogammaglobulinemia (HGG) is a risk factor for development of severe infections after heart transplantation. We performed a clinical trial to preliminarily evaluate the efficacy and safety of early administration of intravenous immunoglobulin (IVIG) for prevention of severe infection in heart recipients with posttransplant IgG HGG. Methods: Twelve heart recipients with IgG HGG detected in a screening phase of the clinical trial (IgG<500 mg/dL) were recruited. Patients received IVIG (Flebogamma 5%), as follows: 2 doses of 200 mg/kg followed by up to 5 additional doses of 300 mg/kg to maintain IgG >750 mg/dL. IgG and specific antibody titers to distinct microorganisms were tested during follow-up. The primary outcome measure was development of severe infection during the study period. Data on the primary outcome were matched with those of 13 recipients with post-transplant HGG who were not included in the clinical trial and with those of 11 recipients who did not develop HGG during the same study period.
Enferm Infec Microbiol Clin, 2003
PloS one, 2015
Reactivation of cytomegalovirus (CMV) has been reported occasionally in immnunocompetent patients... more Reactivation of cytomegalovirus (CMV) has been reported occasionally in immnunocompetent patients in the intensive care unit (ICU). The epidemiology and association of CMV infection with adverse outcome is not well defined in this population. Patients undergoing major heart surgery (MHS) are at a particularly high risk of infection. CMV infection has not been systematically monitored in MSH-ICU patients. We assessed CMV plasma viremia weekly using a quantitative polymerase chain reaction assay in a prospective cohort of immunocompetent adults admitted to the MHS-ICU for at least 72 hours between October 2012 and May 2013. Risk factors for CMV infection and its potential association with continued hospitalization or death by day 30 (composited endpoint) were assessed using univariate and multivariate logistic regression analyses. CMV viremia at any level was recorded in 16.5% of patients at a median of 17 days (range, 3-54 days) after admission to the MHS-ICU. Diabetes (adjusted OR, ...
The Journal of antimicrobial chemotherapy, Jan 21, 2015
Microbiological strategies are necessary to help clinicians discontinue empirical antifungal ther... more Microbiological strategies are necessary to help clinicians discontinue empirical antifungal therapy in patients with suspected invasive candidiasis. Culture methods and biomarkers each show low sensitivity. We analysed the value of combining different biomarkers as a decision-making tool for discontinuing empirical antifungal treatment. We studied stored serum samples from 31 patients with candidaemia (Candida albicans 40%, Candida tropicalis 20%, Candida parapsilosis 18%, Candida glabrata 12% and other 10%) and 50 patients with bacteraemia at Gregorio Marañón Hospital, Madrid, Spain. C. albicans germ tube antibody (CAGTA), mannan antigens (MN), antimannan antibodies (AMN) and (1→3)-β-d-glucan (BDG) were assayed using the manufacturer's and alternative cut-offs to improve the accuracy of the tests. The sensitivity of the biomarkers when used alone was low (58%-84%), but specificity was high (65.8%-92.0%). The best combinations were CAGTA and BDG using cut-offs of 1/80 and 80 pg...
Enfermedades Infecciosas y Microbiología Clínica
There are lots of early examples of biological warfare along the history. Nevertheless, recent ev... more There are lots of early examples of biological warfare along the history. Nevertheless, recent events have made microbiological threat jump from the very restricted and specialized circles to the public arena. Although bioterrorism concerns all segments of the population, the impact on clinical microbiologists is more direct. At this review we have made special mention to laboratory detection systems, as well as to the facilities and laboratory designs requested for this purpose including protection measurements. Preparedness plans and therapeutical considerations have also been mentioned. We think the clinical microbiologist has an undeniable role in the scenario of a potential biological attack, being extremely valuable in diagnosis duties as well as in epidemiological issues, organization and therapeutic advice.
The Pediatric Infectious Disease Journal, 2003
1. Burrage M, Robinson A, Borrow R, et al. Effect of vaccination with carrier protein on response... more 1. Burrage M, Robinson A, Borrow R, et al. Effect of vaccination with carrier protein on response to meningococcal C conjugate vaccines and value of different immunoassays as predictors of protection.
Medical Mycology, 2014
Patients with candidemia may have transient or catheter-related infections without involvement of... more Patients with candidemia may have transient or catheter-related infections without involvement of deep tissues or deep-seated candidiasis. Clinical differentiation of these entities may not be evident with conventional microbiological and imaging methods. Our aim was to determine if the detection of Candida albicans germ tube-specific antibody (CAGTA) in patients with candidemia was related to the extent of the disease. This study was conducted from 2003 to 2012 with 50 patients diagnosed as having candidemia, that is, 29 with deep-seated candidiasis and 21 with non-deep-seated candidiasis. The most common species recovered from samples obtained from these patients were C. albicans, 40%; C. tropicalis, 20%; C. parapsilosis, 18%; and C. glabrata, 12%. Serum samples were processed according to the manufacturer's recommendations (Vircell Microbiologist S.L., Granada, Spain). The CAGTA tests were positive in 1/21 non-deep-seated candidemias (DSCs; 4.76%) and 20/29 DSCs (68.96%; P < 0.01). Accordingly, the values for specificity and positive predictive values of CAGTA for identifying DSC were 95%. We concluded that the presence of a positive CAGTA test in a sample from a patient with candidemia suggests deep-seated candidiasis. Extension screening studies should be considered and origins other than catheters should be searched. Prospective studies are needed to determine the clinical implications of this finding and its potential use in defining the optimal duration of therapy.
Letters in Applied Microbiology, 1993
Rapid non-specific degradation of Serratia marcescens DNA extracted with guanidium thiocyanate, o... more Rapid non-specific degradation of Serratia marcescens DNA extracted with guanidium thiocyanate, occurred within 10 min of incubation with restriction endonuclease enzymes. The described modified method based on chemical and enzymatic deproteinization produced preparations of Ser. marcescens DNA of high yield and quality which did not autodegrade when incubated with restriction endonucleases.
Journal of Hospital Infection, 2001
Clostridium difficile is one of the most frequent causes of hospital-acquired diarrhoea. Our obje... more Clostridium difficile is one of the most frequent causes of hospital-acquired diarrhoea. Our objective was to prove that some stool samples with a direct negative cytotoxicity assay may indeed harbour toxigenic C. difficile and that this can be demonstrated by performing a "second-look" cytotoxicity assay using the isolated C. difficile strains. Over an eight-year period (1992-1999), the 8241 stool samples submitted for direct cell culture from patients with suspected C. difficile-associated diarrhoea (CDAD) were simultaneously plated on cycloserine cefoxitin fructose agar. C. difficile strains isolated from samples with a negative direct cell culture assay were re-tested for toxin production "second-look" cell culture assay). Using both methods 6423 samples (78%) were negative. Of the remaining 1818 samples, 127 (7%) yielded C. difficile isolates which were confirmed as non-producers of toxin by both methods, 1437 (85%) were positive in direct cell culture assay, and 254 were positive only after the "second-look" cell culture assay. Thus, our approach allowed us to detect an extra 15% of toxin-producing strains that could have gone undetected otherwise.The combination of direct-cell culture assay, culture for toxigenic C. difficile and "second-look" cell culture assay enhances the potential for diagnosis of CDAD and enables us to be more efficient with our patient care resources.
The Journal of Heart and Lung Transplantation, 2014
2.48-68.39, p= 0.024). A significant decrease in mean anti-CMV titers (baseline vs. day 30) was o... more 2.48-68.39, p= 0.024). A significant decrease in mean anti-CMV titers (baseline vs. day 30) was observed in both groups (CMV disease: 20419±14483 vs. 14235±11963, p= 0.044; no-CMV disease: 23232±2134 vs. 18247±1747, p< 0.001). There were no significative differences in mean specific anti-CMV titers between both groups in the analyzed study points. Conclusion: In conclusion, CMV-seropositive heart transplant recipients at risk for CMV disease can be identified based on readily assessable immunological biomarkers. Preventive strategies may be selectively targeted toward these patients.
Journal of Clinical Microbiology, 2014
The recently launched Liaison XL Murex HIV Ab/Ag assay (DiaSorin S.p.A) uses chemiluminescence im... more The recently launched Liaison XL Murex HIV Ab/Ag assay (DiaSorin S.p.A) uses chemiluminescence immunoassay technology for the combined qualitative determination of p24 antigen of HIV-1 and specific antibodies to both HIV-1 and HIV-2. We studied 571 serum samples from those submitted to our laboratory for HIV screening. The samples were divided into 3 subsets: subset A, 365 samples collected prospectively during 1 week; subset B, 158 samples from confirmed HIV-positive patients; and subset C, 48 samples with a positive screening result but a negative or indeterminate confirmatory test result. Our standard screening/confirmatory algorithm was used as a reference. In subset A (prospective), 5 samples were positive and 360 negative by the standard procedure. Liaison XL Murex HIV Ab/Ag correctly identified all 5 positive samples (100%) and 357 negative samples (99.2%). In subset B (confirmed positive), all 158 positive samples were in total agreement in both procedures. In subset C (scre...
Journal of Clinical Microbiology, 2014
Frontiers in Cellular and Infection Microbiology
IntroductionSince the COVID-19 outbreak, specific mRNA-based anti-SARS-CoV-2 vaccines have been d... more IntroductionSince the COVID-19 outbreak, specific mRNA-based anti-SARS-CoV-2 vaccines have been developed and distributed worldwide. Because this is the first time that mRNA vaccines have been used, there are several questions regarding their capacity to confer immunity and the durability of the specific anti-SARS-CoV-2 response. Therefore, the objective of this study was to recruit a large cohort of healthcare workers from the Gregorio Marañón Hospital vaccinated with the mRNA-1273 or BNT126b2 vaccines and to follow-up on IgG anti-RBD levels at 8 months post-vaccination.MethodsWe recruited 4,970 volunteers and measured IgG anti-RBD antibodies on days 30 and 240 post-vaccination.ResultsWe observed that both vaccines induced high levels of antibodies on day 30, while a drastic wane was observed on day 240, where mRNA-1273 vaccinated induced higher levels than BNT162b2. Stratifying by vaccine type, age, gender, and comorbidities, we identified that older mRNA-1273-vaccinated volunteer...
Biomedicines
Vaccination against SARS-CoV-2 has become the main method of reducing mortality and severity of C... more Vaccination against SARS-CoV-2 has become the main method of reducing mortality and severity of COVID-19. This work aims to study the evolution of the cellular and humoral responses conferred by two mRNA vaccines after two doses against SARS-CoV-2. On days 30 and 240 after the second dose of both vaccines, the anti-S antibodies in plasma were evaluated from 82 volunteers vaccinated with BNT162b2 and 68 vaccinated with mRNA-1273. Peripheral blood was stimulated with peptides encompassing the entire SARS-CoV-2 Spike sequence. IgG Anti-S antibodies (humoral) were quantified on plasma, and inflammatory cytokines (cellular) were measured after stimulation. We observed a higher response (both humoral and cellular) with the mRNA-1273 vaccine. Stratifying by age and gender, differences between vaccines were observed, especially in women under 48 and men over 48 years old. Therefore, this work could help to set up a vaccination strategy that could be applied to confer maximum immunity.
Journal of Fungi, 2022
There is scarce information on the actual incidence of candidemia in COVID-19 patients. In additi... more There is scarce information on the actual incidence of candidemia in COVID-19 patients. In addition, comparative studies of candidemia episodes in COVID-19 and non-COVID-19 patients are heterogeneous. Here, we assessed the real incidence, epidemiology, and etiology of candidemia in COVID-19 patients, and compared them with those without COVID-19 (2020 vs. 2019 and 2020, respectively). We also genotyped all C. albicans, C. parapsilosis, and C. tropicalis isolates (n = 88), causing candidemia in both groups, providing for the first time a genotypic characterization of isolates gathered in patients with either COVID-19 or non-COVID-19. Incidence of candidemia was higher in patients with COVID-19 than non-COVID-19 (4.73 vs. 0.85 per 1000 admissions; 3.22 vs. 1.14 per 10,000 days of stay). No substantial intergroup differences were found, including mortality. Genotyping proved the presence of a low number of patients involved in clusters, allowing us to rule out rampant patient-to-patien...
Journal of Fungi, 2021
The implementation of 1,3 β-d-glucan (BDG) has been proposed as a diagnostic tool in antifungal s... more The implementation of 1,3 β-d-glucan (BDG) has been proposed as a diagnostic tool in antifungal stewardship programs (ASPs). We aimed to analyze the influence of serum BDG in an ASP for oncologic patients and solid organ transplant (SOT) recipients. We conducted a pre–post study. In the initial period (PRE), the ASP was based on bedside advice, and this was complemented with BDG in the post-period (POST). Performance parameters of the BDG assay were determined. Antifungal (AF) use adequacy was evaluated using a point score. Clinical outcomes and AF costs were also compared before and after the intervention. Overall, 85 patients were included in the PRE-period and 112 in the POST-period. Probable or proven fungal infections were similar in both groups (54.1% vs. 57.1%; p = 0.67). The determination of BDG contributed to improved management in 75 of 112 patients (66.9%). The AF adequacy score improved in the POST-period (mean 7.75 vs. 9.29; p < 0.001). Median days of empiric AF trea...
Journal of Clinical Microbiology, 1999
JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML),... more JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a central nervous system infection that mainly affects AIDS patients. The extensive application of highly active antiretroviral therapy (HAART) is leading to the appearance of “long-term” survival PML patients. A reliable and feasible qualitative-quantitative test for both the detection of JCV and follow-up of its viral burden in this emerging group of patients is clearly required. With this aim, a dual qualitative-quantitative nested PCR is presented in this study for the analysis of JCV DNA in cerebrospinal fluid (CSF). Two newly designed internal controls, one competitive and the other noncompetitive, have been constructed to adapt this PCR to either measure the JCV burden or to allow a highly confident determination of JCV presence or clearance. The analytical sensitivity of the technique allows the detection of 0.01 fg (three genomes) of JCV DNA. Its qualitative application has bee...
Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology, 2018
The Architect HIV Ag/Ab Combo Assay, a fourth-generation ELISA, has proven to be highly reliable ... more The Architect HIV Ag/Ab Combo Assay, a fourth-generation ELISA, has proven to be highly reliable for the diagnosis of HIV infection. However, its high sensitivity may lead to false-positive results. To evaluate the diagnostic performance of Architect in a low-prevalence population and to assess the role of the sample-to-cutoff ratio (S/CO) in reducing the frequency of false-positive results. We conducted a retrospective study of samples analyzed by Architect between January 2015 and June 2017. Positive samples were confirmed by immunoblot (RIBA) or nucleic acid amplification tests (NAATs). Different S/CO thresholds (1, 2.5, 10, 25, and 100) were analyzed to determine sensitivity, specificity, and negative and positive predictive values (NPV, PPV). ROC analysis was used to determine the optimal S/CO. A total of 69,471 samples were analyzed. 709 (1.02%) were positive by Architect. Of these, 63 (8.89%) were false-positive results. Most of them (93.65%) were in samples with S/CO < 10...
Annals of Pharmacotherapy, 2017
Background: Evidence about the use of dolutegravir (DTG) and rilpivirine (RPV) as an antiretrovir... more Background: Evidence about the use of dolutegravir (DTG) and rilpivirine (RPV) as an antiretroviral therapy (ART) in treatment-experienced patients is scarce. Objective: To explore the effectiveness, safety, and costs of switching to a DTG plus RPV regimen in this population. Methods: This observational, prospective study included all treatment-experienced patients who switched to DTG plus RPV between November 2014 and July 2016. Patients were excluded if resistance mutations to integrase inhibitors or RPV were found. The effectiveness endpoint was the proportion of patients who achieved virological suppression (viral load [VL] <50 copies/mL) at week 48 (W48). Safety (incidence of adverse events leading to discontinuation and laboratory abnormalities), adherence, and costs were analyzed. Results: A total of 35 patients were included, and 91.4% were virologically suppressed at baseline. Patients were treated with ART for a median of 14 years (interquartile range = 7-20). At W48, 9...
Enfermedades infecciosas y microbiologia clinica, Mar 25, 2017
Detection of hepatitis C virus (HCV) RNA and the HCV core antigen assay (HCV-Ag) are reliable tec... more Detection of hepatitis C virus (HCV) RNA and the HCV core antigen assay (HCV-Ag) are reliable techniques for the diagnosis of active and chronic HCV infection. Our aim was to evaluate the HCV-Ag assay as an alternative to quantification of HVC RNA. A comparison was made of the sensitivity and specificity of an HCV-Ag assay (204 serum samples) with those of a PCR assay, and the correlation between the two techniques was determined. The sensitivity and specificity of HCV-Ag was 76.6% and 100%, respectively. Both assays were extremely well correlated (Pearson coefficient=0.951). The formula (LogCV=1.15*LogAg+2.26) was obtained to calculate the viral load by PCR from HCV-Ag values. HCV-Ag was unable to detect viral loads below 5000IU/mL. Although the HCV-Ag assay was less sensitive than the PCR assay, the correlation between both assays was excellent. HCV-Ag can be useful as a first step in the diagnosis of acute or chronic HCV infection and in emergency situations.
Transplant Infectious Disease, 2016
Background: Immunoglobulin G (IgG) hypogammaglobulinemia (HGG) is a risk factor for development o... more Background: Immunoglobulin G (IgG) hypogammaglobulinemia (HGG) is a risk factor for development of severe infections after heart transplantation. We performed a clinical trial to preliminarily evaluate the efficacy and safety of early administration of intravenous immunoglobulin (IVIG) for prevention of severe infection in heart recipients with posttransplant IgG HGG. Methods: Twelve heart recipients with IgG HGG detected in a screening phase of the clinical trial (IgG<500 mg/dL) were recruited. Patients received IVIG (Flebogamma 5%), as follows: 2 doses of 200 mg/kg followed by up to 5 additional doses of 300 mg/kg to maintain IgG >750 mg/dL. IgG and specific antibody titers to distinct microorganisms were tested during follow-up. The primary outcome measure was development of severe infection during the study period. Data on the primary outcome were matched with those of 13 recipients with post-transplant HGG who were not included in the clinical trial and with those of 11 recipients who did not develop HGG during the same study period.
Enferm Infec Microbiol Clin, 2003
PloS one, 2015
Reactivation of cytomegalovirus (CMV) has been reported occasionally in immnunocompetent patients... more Reactivation of cytomegalovirus (CMV) has been reported occasionally in immnunocompetent patients in the intensive care unit (ICU). The epidemiology and association of CMV infection with adverse outcome is not well defined in this population. Patients undergoing major heart surgery (MHS) are at a particularly high risk of infection. CMV infection has not been systematically monitored in MSH-ICU patients. We assessed CMV plasma viremia weekly using a quantitative polymerase chain reaction assay in a prospective cohort of immunocompetent adults admitted to the MHS-ICU for at least 72 hours between October 2012 and May 2013. Risk factors for CMV infection and its potential association with continued hospitalization or death by day 30 (composited endpoint) were assessed using univariate and multivariate logistic regression analyses. CMV viremia at any level was recorded in 16.5% of patients at a median of 17 days (range, 3-54 days) after admission to the MHS-ICU. Diabetes (adjusted OR, ...
The Journal of antimicrobial chemotherapy, Jan 21, 2015
Microbiological strategies are necessary to help clinicians discontinue empirical antifungal ther... more Microbiological strategies are necessary to help clinicians discontinue empirical antifungal therapy in patients with suspected invasive candidiasis. Culture methods and biomarkers each show low sensitivity. We analysed the value of combining different biomarkers as a decision-making tool for discontinuing empirical antifungal treatment. We studied stored serum samples from 31 patients with candidaemia (Candida albicans 40%, Candida tropicalis 20%, Candida parapsilosis 18%, Candida glabrata 12% and other 10%) and 50 patients with bacteraemia at Gregorio Marañón Hospital, Madrid, Spain. C. albicans germ tube antibody (CAGTA), mannan antigens (MN), antimannan antibodies (AMN) and (1→3)-β-d-glucan (BDG) were assayed using the manufacturer's and alternative cut-offs to improve the accuracy of the tests. The sensitivity of the biomarkers when used alone was low (58%-84%), but specificity was high (65.8%-92.0%). The best combinations were CAGTA and BDG using cut-offs of 1/80 and 80 pg...
Enfermedades Infecciosas y Microbiología Clínica
There are lots of early examples of biological warfare along the history. Nevertheless, recent ev... more There are lots of early examples of biological warfare along the history. Nevertheless, recent events have made microbiological threat jump from the very restricted and specialized circles to the public arena. Although bioterrorism concerns all segments of the population, the impact on clinical microbiologists is more direct. At this review we have made special mention to laboratory detection systems, as well as to the facilities and laboratory designs requested for this purpose including protection measurements. Preparedness plans and therapeutical considerations have also been mentioned. We think the clinical microbiologist has an undeniable role in the scenario of a potential biological attack, being extremely valuable in diagnosis duties as well as in epidemiological issues, organization and therapeutic advice.
The Pediatric Infectious Disease Journal, 2003
1. Burrage M, Robinson A, Borrow R, et al. Effect of vaccination with carrier protein on response... more 1. Burrage M, Robinson A, Borrow R, et al. Effect of vaccination with carrier protein on response to meningococcal C conjugate vaccines and value of different immunoassays as predictors of protection.
Medical Mycology, 2014
Patients with candidemia may have transient or catheter-related infections without involvement of... more Patients with candidemia may have transient or catheter-related infections without involvement of deep tissues or deep-seated candidiasis. Clinical differentiation of these entities may not be evident with conventional microbiological and imaging methods. Our aim was to determine if the detection of Candida albicans germ tube-specific antibody (CAGTA) in patients with candidemia was related to the extent of the disease. This study was conducted from 2003 to 2012 with 50 patients diagnosed as having candidemia, that is, 29 with deep-seated candidiasis and 21 with non-deep-seated candidiasis. The most common species recovered from samples obtained from these patients were C. albicans, 40%; C. tropicalis, 20%; C. parapsilosis, 18%; and C. glabrata, 12%. Serum samples were processed according to the manufacturer's recommendations (Vircell Microbiologist S.L., Granada, Spain). The CAGTA tests were positive in 1/21 non-deep-seated candidemias (DSCs; 4.76%) and 20/29 DSCs (68.96%; P < 0.01). Accordingly, the values for specificity and positive predictive values of CAGTA for identifying DSC were 95%. We concluded that the presence of a positive CAGTA test in a sample from a patient with candidemia suggests deep-seated candidiasis. Extension screening studies should be considered and origins other than catheters should be searched. Prospective studies are needed to determine the clinical implications of this finding and its potential use in defining the optimal duration of therapy.
Letters in Applied Microbiology, 1993
Rapid non-specific degradation of Serratia marcescens DNA extracted with guanidium thiocyanate, o... more Rapid non-specific degradation of Serratia marcescens DNA extracted with guanidium thiocyanate, occurred within 10 min of incubation with restriction endonuclease enzymes. The described modified method based on chemical and enzymatic deproteinization produced preparations of Ser. marcescens DNA of high yield and quality which did not autodegrade when incubated with restriction endonucleases.
Journal of Hospital Infection, 2001
Clostridium difficile is one of the most frequent causes of hospital-acquired diarrhoea. Our obje... more Clostridium difficile is one of the most frequent causes of hospital-acquired diarrhoea. Our objective was to prove that some stool samples with a direct negative cytotoxicity assay may indeed harbour toxigenic C. difficile and that this can be demonstrated by performing a "second-look" cytotoxicity assay using the isolated C. difficile strains. Over an eight-year period (1992-1999), the 8241 stool samples submitted for direct cell culture from patients with suspected C. difficile-associated diarrhoea (CDAD) were simultaneously plated on cycloserine cefoxitin fructose agar. C. difficile strains isolated from samples with a negative direct cell culture assay were re-tested for toxin production "second-look" cell culture assay). Using both methods 6423 samples (78%) were negative. Of the remaining 1818 samples, 127 (7%) yielded C. difficile isolates which were confirmed as non-producers of toxin by both methods, 1437 (85%) were positive in direct cell culture assay, and 254 were positive only after the "second-look" cell culture assay. Thus, our approach allowed us to detect an extra 15% of toxin-producing strains that could have gone undetected otherwise.The combination of direct-cell culture assay, culture for toxigenic C. difficile and "second-look" cell culture assay enhances the potential for diagnosis of CDAD and enables us to be more efficient with our patient care resources.
The Journal of Heart and Lung Transplantation, 2014
2.48-68.39, p= 0.024). A significant decrease in mean anti-CMV titers (baseline vs. day 30) was o... more 2.48-68.39, p= 0.024). A significant decrease in mean anti-CMV titers (baseline vs. day 30) was observed in both groups (CMV disease: 20419±14483 vs. 14235±11963, p= 0.044; no-CMV disease: 23232±2134 vs. 18247±1747, p< 0.001). There were no significative differences in mean specific anti-CMV titers between both groups in the analyzed study points. Conclusion: In conclusion, CMV-seropositive heart transplant recipients at risk for CMV disease can be identified based on readily assessable immunological biomarkers. Preventive strategies may be selectively targeted toward these patients.
Journal of Clinical Microbiology, 2014
The recently launched Liaison XL Murex HIV Ab/Ag assay (DiaSorin S.p.A) uses chemiluminescence im... more The recently launched Liaison XL Murex HIV Ab/Ag assay (DiaSorin S.p.A) uses chemiluminescence immunoassay technology for the combined qualitative determination of p24 antigen of HIV-1 and specific antibodies to both HIV-1 and HIV-2. We studied 571 serum samples from those submitted to our laboratory for HIV screening. The samples were divided into 3 subsets: subset A, 365 samples collected prospectively during 1 week; subset B, 158 samples from confirmed HIV-positive patients; and subset C, 48 samples with a positive screening result but a negative or indeterminate confirmatory test result. Our standard screening/confirmatory algorithm was used as a reference. In subset A (prospective), 5 samples were positive and 360 negative by the standard procedure. Liaison XL Murex HIV Ab/Ag correctly identified all 5 positive samples (100%) and 357 negative samples (99.2%). In subset B (confirmed positive), all 158 positive samples were in total agreement in both procedures. In subset C (scre...
Journal of Clinical Microbiology, 2014