María Teresa Jiménez de Anta

Cross-reactivity of anti-Mycobacterium gordonae antibodies with the major mitochondrial autoantigens in primary biliary cirrhosis

Primary biliary cirrhosis is a chronic cholestatic liver disease associated with autoimmune disorders. Antimitochondrial autoantibodies and granulomatous portal lesions are characteristic in primary biliary cirrhosis. Since granuloma may be induced by Mycobacteria, and there is evidence implicating Mycobacteria as infectious agents capable of initiating autoimmunity, a study was performed to determine the presence of antibodies against 10 atypical Mycobacteria in 19 patients with primary biliary cirrhosis, and in 35 controls (25 patients with other chronic liver diseases and 10 healthy subjects). All primary biliary cirrhosis sera and none of the controls reacted with the extract from Mycobacterium gordonae, showing identical recognition profiles with two polypeptides of 70-65 and 55 kDa. No other reaction was found in primary biliary cirrhosis patients and in controls with the extracts from the other nine atypical Mycobacteria tested. Eluted immunoglobulins which reacted with the 70-65 and 55 kDa polypeptides from M. gordonae, bound to the mitochondrial antigens PDH-E2 and BCKDH-E2. Furthermore, when the extract from M. gordonae was tested with eluted immunoglobulins from recognized PDH-E2 and BCKDH-E2 by primary biliary cirrhosis patients, we observed both 70-65 and 55 kDa polypeptides. These data indicate that antibodies to M. gordonae, found in all primary biliary cirrhosis patients, cross-react with the major mitochondrial targets of the disease. We suggest that M. gordonae may play a potential pathogenic role in primary biliary cirrhosis.

New rapid antigen test for diagnosis of pneumococcal meningitis

Conventional diagnostic methods for bacterial meningitis are frequently not rapid or sensitive enough to guide initial antimicrobial therapy. Streptococcus pneumoniae is the most frequent and severe cause of community-acquired bacterial meningitis and treatment is complicated by the increasing prevalence of antimicrobial resistance to third-generation cephalosporins. We used a new rapid antigen test in the cerebrospinal fluid and urine of patients with suspected bacterial meningitis, and found it to be highly sensitive and specific for the detection of pneumococci. This test might help guide initial therapy for bacterial meningitis according to the local rates of pneumococcal antimicrobial resistance.

Relationship of Phylogenetic Background, Biofilm Production, and Time to Detection of Growth in Blood Culture Vials with Clinical Variables and Prognosis Associated with Escherichia coli Bacteremia

ABSTRACT In patients with Escherichia coli bacteremia, data on the relationship of phylogenetic background, biofilm production, and degree of bacteremia with clinical variables and prognosis are scarce. During a 1-year period, all adults with bacteremia due to Escherichia coli diagnosed at a university center were enrolled. Determination of phylogenetic background, biofilm production, and genotyping was performed with all strains, and the time to positivity of blood culture vials was recorded. A total of 185 episodes of diverse-source E. coli bacteremia was analyzed. Strains of phylogroup D were predominant (52%). Phylogroup A isolates were associated with pneumonia and prior antibiotic intake, B1 with an abdominal source of infection, B2 with the absence of urological abnormalities, and D with urological abnormalities and age below 65 years. Resistance to antibiotics and no biofilm production were concentrated in phylogroup A strains. Biofilm production was not associated with any clinical variable. An immunocompromising condition (odds ratio [OR] = 5.01, 95% confidence interval [CI] = 1.4 to 17.9), peritonitis (OR = 17, 95% CI = 3.32 to 87), pneumonia (OR = 9.97, 95% CI = 1.96 to 50.6), and ≤7 h to bacteremia detection (OR = 4.37, 95% CI = 1.38 to 13.8) were the best predictors of a fatal outcome. Results from this study suggest that the distribution of phylogenetic backgrounds among E. coli strains involved in diverse-source bacteremia may be subject to geographical variation and that, in afflicted individuals, some high-risk sources, the patients underlying condition, and the degree of bacteremia are more important than microbial factors in determining the outcome. Time to positivity of blood culture vials may be a variable of potential clinical impact.

Hepatitis G virus infection in chronic hepatitis C: frequency, features and response to interferon therapy

BACKGROUND/AIMS The pathogenic relevance of the hepatitis G virus (HGV) and its sensitivity to interferon are currently under investigation. This study aimed to investigate the prevalence of HGV infection in patients with chronic hepatitis C and to elucidate if HGV co-infection modifies the clinical course and the response to interferon therapy in this disease. METHODS HGV-RNA was investigated by reverse transcription-polymerase chain reaction in serum from 143 consecutive patients who received interferon alpha-2b (3 MU t.i.w.) for 24 weeks. Baseline features and response to therapy in HGV-infected and non-infected patients were compared. To assess the antiviral effect of interferon, serial quantitative measurement of HCV-RNA and HGV-RNA in serum was performed in patients co-infected with HCV and HGV. RESULTS Eight patients (5.6%) presented HGV-RNA sequences in serum. No significant differences were found between HGV-infected and non-infected patients in relation to age, sex, source of infection, liver function tests, liver histology and HCV genotype, nor in the biochemical response to interferon, which was sustained in 12% and 15%, transient in 37% and 30% and absent in 50% and 55% of HGV-infected and non-infected patients, respectively. HGV-RNA became negative in all treated patients, but sustained viral inhibition was observed only in those with low viral load. CONCLUSIONS The prevalence of HGV infection in HCV-infected patients is relatively low in our geographical area. HGV co-infection does not appear to modify the clinical presentation nor the response to interferon in chronic hepatitis C. HGV is sensitive to interferon, particularly if pre-treatment viral load is low.

Permanent response to alpha-interferon therapy in chronic hepatitis C is preceded by rapid clearance of HCV-RNA from serum

BACKGROUND/AIMS Prediction of response to interferon therapy is important in the management of chronic hepatitis C. Pre-therapy data are valuable but they may be inaccurate in some cases. Our aim was to investigate whether the biochemical and virological events that occur early during interferon therapy in chronic hepatitis C may predict the final result of the treatment. METHODS ALT and serum HCV-RNA were serially measured in 53 HCV-RNA-positive patients who received a standard 6-month course of interferon therapy. Eleven patients with a sustained response, 23 who responded but subsequently relapsed and 19 who did not respond were studied. HCV-RNA was measured with a commercial kit (Amplicor HCV). RESULTS After 4 weeks of treatment, HCV-RNA became negative in 73% of sustained responders, in 26% of transient responders (p = 0.02) and in none of the non-responders. Corresponding figures after 8 weeks of therapy were 82% in sustained responders, 61% in transient responders and 9% in non-responders. The difference between sustained and transient responders at this time was not significant. After 4 weeks of therapy, 82% of sustained responders, 52% of transient responders and none of the non-responders presented normalization of alanine transferase. The difference between sustained and transient responders was not significant. Corresponding figures for normalization of alanine transferase at 8 weeks were 82%, 96% and 0% respectively. At the end of treatment, all sustained responders, 70% of transient responders and none of the non-responders had cleared HCV-RNA from serum. CONCLUSIONS A rapid normalization of alanine transferase induced by interferon therapy is associated with response, but does not differentiate between transient and permanent response. In contrast, clearance of HCV-RNA after 4 weeks of treatment, but not after 8 weeks, is significatively associated with sustained response. Testing for HCV-RNA early during interferon administration may be valuable for further decisions concerning therapy in patients with chronic hepatitis C.

Pneumocystis jirovecii pneumonia in Spanish HIV-infected patients in the combined antiretroviral therapy era: prevalence of dihydropteroate synthase mutations and prognostic factors of mortality

The incidence of Pneumocystis jirovecii pneumonia (PCP) in HIV-infected patients has decreased thanks to sulfa prophylaxis and combined antiretroviral therapy. The influence of P. jirovecii dihydropteroate synthase (DHPS) gene mutations on survival is controversial and has not been reported in Spain. This prospective multicenter study enrolled 207 HIV-infected patients with PCP from 2000 to 2004. Molecular genotyping was performed on stored specimens. Risk factors for intensive care unit (ICU) admission and mortality were identified using a logistic regression model. Seven patients (3.7%; 95% confidence interval [CI], 1.5-7.5%) had DHPS mutations. Overall mortality was 15% (95% CI, 10-21%), rising to 80% (95% CI, 61-92%) in patients requiring mechanical ventilation. None of the patients with DHPS mutants died, nor did they need ICU admission or mechanical ventilation. PaO(2) <60 mm Hg at admission was a predictor of ICU admission (P = 0.01), and previous antiretroviral therapy predicted non-ICU admission (P = 0.009). PaO(2) <60 mm Hg at admission and ICU admission during the 1st week were predictors of mortality (P = 0.03 and P < 0.001, respectively). The prevalence of DHPS mutants in Spain is low and is not associated with a worse outcome. Severe respiratory failure at admission is the strongest predictor of PCP outcome.

D225G mutation in the hemagglutinin protein found in 3 severe cases of 2009 pandemic influenza A (H1N1) in Spain.

From 27 April to 16 December 2009, we analyzed the hemagglutinin gene sequence of 2009 pandemic influenza A (H1N1) virus in 189 respiratory specimens. We only found the D225G mutation in 3 severe cases. However, it was not found in samples from other cases with or without clinical criteria of severity. The biologic significance of this mutation remains still unclear.

Simultaneous Identification of Mycobacterium Genus and Mycobacterium tuberculosis Complex in Clinical Samples by 5′-Exonuclease Fluorogenic PCR

ABSTRACT Early diagnosis of tuberculosis and screening of other mycobacteria is required for the appropriate management of patients. We have therefore developed a 5′-exonuclease fluorogenic PCR assay in a single-tube balanced heminested format that simultaneously detects Mycobacterium tuberculosis complex (MTC) and members of the Mycobacterium genus (MYC) using the 16S ribosomal DNA target directly on clinical samples. One hundred twenty-seven clinical samples (65 smear negative and 62 smear positive) with a positive culture result from 127 patients were tested, including 40 negative control specimens. The finding of both a positive MTC and probe value and a positive MYC probe value confirmed the presence of MTC or mycobacteria with a 100% positive predictive value. However, a negative value for MTC or MYC did not discount the presence of mycobacteria in the specimen. Interestingly, the addition of the MYC probe allowed the diagnosis of an additional 7% of patients with tuberculosis and rapid screening of nontuberculous mycobacteria (NTM). Thus, over 75% of the patients were diagnosed with mycobacterial disease by PCR. The sensitivity was much higher on smear-positive samples (90.3%) than smear-negative samples (49.2%) and was slightly higher for MTC than NTM samples. With regard to the origin of the sample, MTC pulmonary samples gave better results than others. In conclusion, we believe this test may be useful for the rapid detection of mycobacteria in clinical samples and may be a valuable tool when used together with conventional methods and the clinical data available.

Selection and viral load kinetics of an oseltamivir-resistant pandemic influenza A (H1N1) virus in an immunocompromised patient during treatment with neuraminidase inhibitors

Prolonged viral excretion in immunocompromised hosts leads to long oseltamivir treatment and to the subsequent development of oseltamivir-resistant pandemic influenza virus selection. We report the selection and nasopharyngeal shedding kinetics of an oseltamivir-resistant strain in a hospitalized immunocompromised patient with prolonged influenza illness. Viral load quantification and genotyping methods were performed from 7 serial nasopharyngeal samples. Before initial oseltamivir treatment, the viral load was 5.78 log(10) copies/mL of sample and only wild-type virus population was detected. The nasopharyngeal viral load remained above the detection limit although there was a second course of oseltamivir treatment. Twelve days after the onset of symptoms, an oseltamivir-resistant strain was selected. After 12 days of inhaled zanamivir treatment, the patient was discharged asymptomatic. The study emphasizes the importance of viral load quantification and surveillance of emergence of resistant strains prospectively because the information provided has important implications in the clinical management of the patient.

Influenza C virus surveillance during the first influenza A (H1N1) 2009 pandemic wave in Catalonia, Spain

Although particular attention is paid to influenza A and B virus isolates during influenza surveillance, influenza C virus (FLUCV) coexisted during the first influenza A (H1N1) 2009 pandemic wave during the 2009-2010 season. From 27 April 2009 to 9 May 2010, 12 strains of FLUCV were detected in specimens collected from 1713 nonhospitalized patients with upper respiratory tract illness using a molecular method. Half of the patients with FLUCV infection were older than 14 years. The most frequent symptoms were cough and fever, similar to other viral respiratory infections. Phylogenetic analysis of the hemagglutinin-esterase gene revealed that the strains belonged to the C/Kanagawa/1/76-related and C/Sao Paulo/378/82-related lineages, demonstrating their co-circulation in Catalonia. In addition to regular virological surveillance that provides information about the incidence and the exact role of FLUCV in acute viral respiratory infections in the general population, the genetic lineage identification offers additional data for epidemiological purposes.