A new MALDI-TOF approach for the quick sequence type identification of Legionella pneumophila.

BACKGROUND: Recently, MALDI-TOF has emerged as a quick tool for bacterial typing. The aim was to evaluate if MALDI-TOF based typing of Legionella pneumophila can achieve the same discriminatory power as that of the Sequence Based Typing (SBT) method. METHODS: The Sequence Type (ST) was obtained from the 90 strains included in the training set and an in-house MALDI-TOF library based on the Main Spectra Profile (MSP) was generated for the identification of such ST. Then, our library was validated by three procedures: a) creating a dendrogram, b) searching for specific peaks present exclusively in each MSP entry, and c) analysing a validation set composed of 14 strains with known ST. Fully characterized L. pneumophila ATCC 33152, which belongs to ST 36, was used as a control strain. RESULTS: In the training set, 17 strains belonged to ST 1, 1 to ST 20, 63 to ST 22, 1 to ST 146, 6 to ST 578, and 2 to ST 1086. Specific peaks present in each MSPs spectrum, which are considered type-specific biomarkers, ranged from 2 to 11; more concretely, MSP for ST 1 identification shows 2 specific peaks; MSP for ST 20 identification: 9 specific peaks; MSP for ST 22 and ST 36 identification: 11 specific peaks; MSP for ST 146 identification: 5 specific peaks; and MSP for ST 578 and ST 1086 identification: 3 specific peaks. Using the validation set (nine strains belonging to ST 22 and five to ST 1), MALDI-TOF assigned accurately the ST in 30 min per tested strain with a full match. CONCLUSIONS: The ST of L. pneumophila can be identified and reported in few minutes directly from colonies grown on BCYE agar using MALDI-TOF.

Quick identification and epidemiological characterization of Francisella tularensis by MALDI-TOF mass spectrometry.

INTRODUCTION: Currently, Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) is being evaluated for its efficacy as a fast bacterial typing tool due to its great speed compared to other molecular methods. In this study, we evaluated MALDI-TOF as a tool for quick identification and typing of Francisella tularensis. MATERIALS AND METHODS: This study encompassed 86 strains from two different geographical origins (Spain and the Czech Republic), which were previously characterised by Pulsed-Field Gel Electrophoresis (PFGE) and Multiple-Locus Variable Number Tandem Repeat Analysis (MLVA). The direct colony method was used for microbial identification. High-quality spectra of the 86 strains were obtained and their main spectra profiles (MSPs) were created for epidemiological typing using MALDI-TOF. Based on the MSPs, principal components were generated and a dendrogram was constructed. An in-house MALDI-TOF library entry was created for each group of PFGE and MLVA strains based on their high-quality spectra. Two dendrograms were obtained using these entries and the unique peaks in each entry were searched. RESULTS: All strains were correctly identified to the species level. No clear divisions were found in the 86-strain dendrogram; however, Spanish and Czech strains appeared separately in dendrograms created using MLVA and PFGE entries. Entries from our in-house MALDI-TOF library revealed 2-4 biomarker peaks for the detection of the five PFGE groups and 1-12 biomarker peaks for the detection of the seven MLVA groups. Finally, two and one specific biomarkers were found in the Czech and Spanish strains, respectively. CONCLUSION: MALDI-TOF can be used to accurately identify F. tularensis strains in less than 15 min. Moreover, data on geographical origin and PFGE and MLVA groups could be obtained in less than one hour after colony growing.

[Seroprevalence of viral hepatitis in a representative general population of an urban public health area in Castilla y León (Spain)]. / Seroprevalencia de las hepatitis virales en población general representativa de una zona básica de salud urbana en Castilla y León.

INTRODUCTION: Viral hepatitis is a major social, health and economic problem worldwide, requiring strict epidemiological control. METHODS: This study presents the viral hepatitis seroprevalence in a representative sample from an urban health care area in Valladolid (Spain). RESULTS: Antibody prevalence was as follows: anti-HAV 52%; anti-HBc, 8.2%; anti-HCV, 1.1%; anti-HEV, 0.8%; and anti-HGV 5.8%. Prevalence of anti-HAV, anti-HBc and anti-HGV increased significantly with age (P < 0.005 in all cases). In individuals younger than 20, prevalence of anti-HAV was 3.8%, anti-HBc < 0.28% and anti-HGV 1.3%. In the 20-39 year-old group, seroprevalence against HAV was associated with low educational levels (P = 0.009) and with birth in other provinces (P = 0.016). Anti-HBc seroprevalence was mainly associated with three factors: prior hospitalization before 1990 (P = 0.002; OR 3.32 [1.48-7.42]); compulsory military service before 1990 (P < 0.0001; OR 37.33 [3.68-378.03]); and acupuncture treatments (P = 0.018; OR 57.75 [26.17-127.42]). Seroprevalence against HGV was associated with hospitalizations before 1990 (P = 0.019; OR = 2.969 [1.154-7.639]). Seropositive status to HCV revealed a transfusion history (2 cases), hospitalization (1 case) or drug addiction (1 case). Only one case among those seropositive to HEV had a history of a prior trip to a HEV-endemic area. CONCLUSIONS: Our study shows that the seroprevalences of viral hepatitis in a representative sample of urban population of Castille and Leon are similar to the seroprevalences observed in the rest of Spain and other developed countries, lower than the ones observed in the studies performed in Spain in the last 20 years due to the measures of prophylaxis that were taken.

Seroprevalencia de las hepatitis virales en población general representativa de una zona básica de salud urbana en Castilla y León / Seroprevalence of viral hepatitis in a representative general population of an urban public health area in Castilla y León (Spain)

Introducción. Las hepatitis virales constituyen uno de los principales problemas sociosanitarios y económicos a nivel mundial por lo que precisan un estrecho control epidemiológico. Métodos. En el presente trabajo estudiamos la seroprevalencia de las hepatitis virales una muestra representativa de la población de una zona básica de salud urbana en Valladolid (España). Resultados. La prevalencia de anticuerpos anti-VHA (AcVHA) fue del 52%, de HBcAc del 8,2%, de AcVHC del 1,1%, de AcVHE 0,8% y AcVHG 5,8%. La prevalencia de AcVHA, HBcAc y AcVHG aumenta significativamente con la edad (p < 0,005 en todos los casos). En menores de 20 años la prevalencia de AcVHA es del 3,8%, HBcAc < 0,28% y AcVHG 1,3%. En el grupo de edad de 20-39 años, la seroprevalencia frente al VHA se asocia con niveles educativos bajos (p 5 0,009) y con el nacimiento en otras provincias (p 5 0,016). La seroprevalencia de HBcAc se asocia principalmente con hospitalizaciones anteriores a 1990 (p 5 0,002; OR: 3,32 [1,48-7,42]), realización del servicio militar obligatorio anterior a 1990 (p < 0,0001; OR: 37,33 [3,68-378,03]) y prácticas de acupuntura (p 5 0,018; OR: 57,75 [26,17-127,42]). La seroprevalencia frente a VHG se asocia con hospitalizaciones antes de 1990 (p 5 0,019; OR: 2,969 [1,154-7,639]). Los seropositivos frente a VHC tenían antecedentes de transfusiones (2 casos) hospitalización (1 caso) o drogadicción (1 caso). De los seropositivos frente a VHE sólo un caso tenía antecedentes de viaje a zona endémica para VHE. Conclusiones. Nuestro estudio muestra que las seroprevalencias de las hepatitis virales en una muestra representativa de población urbana de Castilla y León son similares a las seroprevalencias obtenidas en el resto de España y de los países desarrollados, inferior a la observada en los estudios realizados en España en los últimos 20 años consecuencia de las medidas profilácticas adoptadas (AU)

Introduction. Viral hepatitis is a major social, health and economic problem worldwide, requiring strict epidemiological control. Methods. This study presents the viral hepatitis seroprevalence in a representative sample from an urban health care area in Valladolid (Spain). Results. Antibody prevalence was as follows: anti-HAV 52%; anti-HBc, 8.2%; anti-HCV, 1.1%; anti-HEV, 0.8%; and anti-HGV 5.8%. Prevalence of anti-HAV, anti-HBc and anti-HGV increased significantly with age (P < 0.005 in all cases). In individuals younger than 20, prevalence of anti-HAV was 3.8%, anti-HBc < 0.28% and anti-HGV 1.3%. In the 20-39 year-old group, seroprevalence against HAV was associated with low educational levels (P 5 0.009) and with birth in other provinces (P 5 0.016). Anti-HBc seroprevalence was mainly associated with three factors: prior hospitalization before 1990 (P 5 0.002; OR 3.32 [1.48-7.42]); compulsory military service before 1990 (P < 0.0001; OR 37.33 [3.68-378.03]); and acupuncture treatments (P 5 0.018; OR 57.75 [26.17-127.42]). Seroprevalence against HGV was associated with hospitalizations before 1990 (P 5 0.019; OR 5 2.969 [1.154-7.639]). Seropositive status to HCV revealed a transfusion history (2 cases), hospitalization (1 case) or drug addiction (1 case). Only one case among those seropositive to HEV had a history of a prior trip to a HEV-endemic area. Conclusions. Our study shows that the seroprevalences of viral hepatitis in a representative sample of urban population of Castille and Leon are similar to the seroprevalences observed in the rest of Spain and other developed countries, lower than the ones observed in the studies performed in Spain in the last 20 years due to the measures of prophylaxis that werw taken (AU)

Seroepidemiologic study of Leishmania infantum infection in Castilla-Leon, Spain.

Leishmaniasis has increased in importance in recent years because infection with human immunodeficiency virus (HIV) has emerged as a risk factor for this disease. However, the actual prevalence of leishmaniasis in the general population of Spain is unknown. We present a study of the seroprevalence of infection with Leishmania infantum in the general population of Castilla-Leon, Spain. A random sample of individuals presenting to health care clinics (4,825 sera) and of HIV-infected patients in the autonomous community of Castilla-Leon was collected in 1996. The sero-prevalence of antibodies to L. infantum was determined by an indirect enzyme immunoassay and found to be 4.9% in the general population. There was a significant increase in seroprevalence with age (P = 0.001), from 3.96% in those 14-20 years old to 7.2% in those > 70 years old. There were no significant differences between women and men (5.0% versus 4.9%; P = 0.9534). Seroprevalence was significantly higher in people from rural areas than in those from cities (6.0% versus 3.4%; P = 0.001). Patients infected with HIV had a seroprevalence for L. infantum of 64.0%. No differences were observed between women and men, and prevalence did not increase with age.