Irina Nastassja Riediger

Molecular identification and typing of Mycobacterium massiliense isolated from postsurgical infections in Brazil

OBJECTIVE One hundred thirty-one cases of postsurgical infections were reported in Southern Region of Brazil between August 2007 and January 2008. Thirty-nine (29.8%) cases were studied; this report describes epidemiological findings, species identification, antimicrobial susceptibility and clonal diversity of rapidly growing mycobacteria isolated in this outbreak. METHODS All 39 isolates were analyzed by Ziehl-Nielsen stained smear, bacterial culture and submitted to rpoB partial gene sequencing for identification. The isolates were also evaluated for their susceptibility to amikacin, cefoxitin, clarithromycin, ciprofloxacin, doxycycline, tobramycin and sulfamethoxazole. RESULTS Thirty-six isolates out of the confirmed cases were identified as Mycobacterium massiliense and the remaining three were identified as Mycobacterium abscessus, Mycobacterium chelonae and Mycobacterium fortuitum. All M. massiliense isolates were susceptible to amikacin (MIC90 = 8 µg/mL) and clarithromycin (MIC90 = 0.25 µg/mL) but resistant to cefoxitin, ciprofloxacin, doxycycline, tobramycin and sulfamethoxazole. Molecular analysis by pulsed-field gel electrophoresis clustered all 36 M. massiliense isolates and showed the same pattern (BRA 100) observed in three other outbreaks previously reported in Brazil. CONCLUSIONS These findings suggest a common source of infection for all patients and reinforce the hypotheses of spread of M. massiliense BRA100 in Brazilian hospital surgical environment in recent years.

Comparative performance evaluation of hepatitis C virus genotyping based on the 5' untranslated region versus partial sequencing of the NS5B region of brazilian patients with chronic hepatitis C.

BackgroundGenotyping of hepatitis C virus (HCV) has become an essential tool for prognosis and prediction of treatment duration. The aim of this study was to compare two HCV genotyping methods: reverse hybridization line probe assay (LiPA v.1) and partial sequencing of the NS5B region.MethodsPlasma of 171 patients with chronic hepatitis C were screened using both a commercial method (LiPA HCV Versant, Siemens, Tarrytown, NY, USA) and different primers targeting the NS5B region for PCR amplification and sequencing analysis.ResultsComparison of the HCV genotyping methods showed no difference in the classification at the genotype level. However, a total of 82/171 samples (47.9%) including misclassification, non-subtypable, discrepant and inconclusive results were not classified by LiPA at the subtype level but could be discriminated by NS5B sequencing. Of these samples, 34 samples of genotype 1a and 6 samples of genotype 1b were classified at the subtype level using sequencing of NS5B.ConclusionsSequence analysis of NS5B for genotyping HCV provides precise genotype and subtype identification and an accurate epidemiological representation of circulating viral strains.

Development of Hepatitis C Virus Genotyping by Real-Time PCR Based on the NS5B Region

Background Hepatitis C virus (HCV) genotyping is the most significant predictor of the response to antiviral therapy. The aim of this study was to develop and evaluate a novel real-time PCR method for HCV genotyping based on the NS5B region. Methodology/Principal Findings Two triplex reaction sets were designed, one to detect genotypes 1a, 1b and 3a; and another to detect genotypes 2a, 2b, and 2c. This approach had an overall sensitivity of 97.0%, detecting 295 of the 304 tested samples. All samples genotyped by real-time PCR had the same type that was assigned using LiPA version 1 (Line in Probe Assay). Although LiPA v. 1 was not able to subtype 68 of the 295 samples (23.0%) and rendered different subtype results from those assigned by real-time PCR for 12/295 samples (4.0%), NS5B sequencing and real-time PCR results agreed in all 146 tested cases. Analytical sensitivity of the real-time PCR assay was determined by end-point dilution of the 5000 IU/ml member of the OptiQuant HCV RNA panel. The lower limit of detection was estimated to be 125 IU/ml for genotype 3a, 250 IU/ml for genotypes 1b and 2b, and 500 IU/ml for genotype 1a. Conclusions/Significance The total time required for performing this assay was two hours, compared to four hours required for LiPA v. 1 after PCR-amplification. Furthermore, the estimated reaction cost was nine times lower than that of available commercial methods in Brazil. Thus, we have developed an efficient, feasible, and affordable method for HCV genotype identification.

A Novel Hepatitis C Virus Genotyping Method Based on Liquid Microarray

The strategy used to treat HCV infection depends on the genotype involved. An accurate and reliable genotyping method is therefore of paramount importance. We describe here, for the first time, the use of a liquid microarray for HCV genotyping. This liquid microarray is based on the 5′UTR — the most highly conserved region of HCV — and the variable region NS5B sequence. The simultaneous genotyping of two regions can be used to confirm findings and should detect inter-genotypic recombination. Plasma samples from 78 patients infected with viruses with genotypes and subtypes determined in the Versant™ HCV Genotype Assay LiPA (version I; Siemens Medical Solutions, Diagnostics Division, Fernwald, Germany) were tested with our new liquid microarray method. This method successfully determined the genotypes of 74 of the 78 samples previously genotyped in the Versant™ HCV Genotype Assay LiPA (74/78, 95%). The concordance between the two methods was 100% for genotype determination (74/74). At the subtype level, all 3a and 2b samples gave identical results with both methods (17/17 and 7/7, respectively). Two 2c samples were correctly identified by microarray, but could only be determined to the genotype level with the Versant™ HCV assay. Genotype “1” subtypes (1a and 1b) were correctly identified by the Versant™ HCV assay and the microarray in 68% and 40% of cases, respectively. No genotype discordance was found for any sample. HCV was successfully genotyped with both methods, and this is of prime importance for treatment planning. Liquid microarray assays may therefore be added to the list of methods suitable for HCV genotyping. It provides comparable results and may readily be adapted for the detection of other viruses frequently co-infecting HCV patients. Liquid array technology is thus a reliable and promising platform for HCV genotyping.

DETECTION OF RDRIO STRAIN OF MYCOBACTERIUM TUBERCULOSIS IN TAPIRS (TAPIRUS TERRESTRIS) FROM A ZOO IN BRAZIL

Tuberculosis is a chronic infection caused by strains of the Mycobacterium tuberculosis complex and occurs in both animal and human populations. The death of a tapir showing purulent material and a hard mass in the lungs at necropsy raised suspicion of a potential disease caused by mycobacteria species in a Brazilian zoo. Later, two other tapirs with similar signs died and were further investigated. Polymerase chain reaction (PCR) from bronco-alveolar lavages was performed, and both animals tested positive for the RD(Rio) strain of M. tuberculosis, which is a recently discovered Latin American-Mediterranean sublineage and the main cause of human tuberculosis in Rio de Janeiro, Brazil. To investigate the possibility of human infection and the source of transmission, all 50 zoo employees underwent tuberculin skin testing; four were reactive, but radiographic exams and direct sample staining did not suggest tuberculosis. Thus, direct human to animal transmission was not proven. However, the presence of RD(Rio) M. tuberculosis in tapirs highlights the lack of attention to diseases that human beings may transmit to wildlife.

AN OUTBREAK OF TUBERCULOSIS BY MYCOBACTERIUM BOVIS IN COATIS (NASUA NASUA)

Abstract:  Mycobacterium tuberculosis complex, which includes Mycobacterium bovis, infrequently causes severe or lethal disease in captive wildlife populations. A dead coati from a wildlife triage center showing pulmonary lesions compatible with tuberculosis had raised suspicion of a potential disease caused by mycobacteria species and was further investigated. Four native coatis (Nasua nasua) with suspected mycobacterial infection were sedated, and bronchoalveolar lavages and tuberculin skin tests (TSTs) were performed. All animals tested positive upon TST. Mycobacterial culturing, Ziehl–Neelsen staining, and genetic testing were performed on postmortem samples and the etiologic agent was identified as M. bovis. Molecular genetic identification using a polymerase chain reaction panel was crucial to achieving a definitive diagnosis.

Epstein-Barr virus: general factors, virus-related diseases and measurement of viral load after transplant

The Epstein-Barr virus is responsible for infectious mononucleosis syndrome and is also closely associated to several types of cancer. The main complication involving Epstein-Barr virus infection, both in recipients of hematopoietic stem cells and solid organs, is post-transplant lymphoproliferative disease. The importance of this disease has increased interest in the development of laboratory tools to improve post-transplant monitoring and to detect the disease before clinical evolution. Viral load analysis for Epstein-Barr virus through real-time polymerase chain reaction is, at present, the best tool to measure viral load. However, there is not a consensus on which sample type is the best for the test and what is its predictive value for therapeutic interventions.

Whole-Genome Characterization of a Novel Human Influenza A(H1N2) Virus Variant, Brazil

We report the characterization of a novel reassortant influenza A(H1N2) virus not previously reported in humans. Recovered from a a pig farm worker in southeast Brazil who had influenza-like illness, this virus is a triple reassortant containing gene segments from subtypes H1N2 (hemagglutinin), H3N2 (neuraminidase), and pandemic H1N1 (remaining genes).

Molecular epidemiology of influenza B virus and implications in immunization strategy, Southern Brazil

Epidemiological indicators have shown the substantial impact of influenza B (Flu B) on the development of severe acute respiratory infection (SARI) and on mortality rates. In Brazil, the trivalent vaccine, composed of only one Flu B lineage is available. We investigated Flu B infections in clinical samples collected by the epidemiological surveillance service of Paraná State, Brazil, from 2013 to 2016. The Flu B lineages Yamagata- (B/Yam) and Victoria-like (B/Vic) were identified using the qRT-PCR assay, and notification forms were reviewed. Among 379 Flu B positive samples evaluated, 370 (98%) were characterized as B/Yam or B/Vic lineages. Both co-circulated with a frequency of 47% and 53%, respectively. B/Yam infected equally both genders, while B/Vic was more frequent in females (71%). The median age of patients infected by B/Vic (23y; 11-35) was lower than that of patients infected by B/Yam (32y; 12-50). Mismatch between the vaccine and the circulating strain was observed in the 2013 season, with a high number of SARI cases. B/Vic lineage was associated with a larger number of SARI cases (62%), while B/Yam with influenza-like illness (ILI) (61%). Differences were observed in the strains circulating in separate regions of Paraná State. B/Vic was prevalent in the northwestern (67%) and B/Yam in the southeastern region (60%). The unpredictability of Flu B lineage circulation causes a substantial increase in severe disease during epidemics in a vaccine mismatch season. In addition, the differences in the epidemiological profile of the target population of Flu B infections in relation to other respiratory viruses, as well as among the B/Vic and B/Yam lineages may also be associated to an increase in disease burden. These findings have direct consequences on vaccination strategies. Therefore, further molecular epidemiology studies of Flu B in Brazil are required to corroborate these primary results.