Cryptococcus gattii in North American Pacific Northwest: Whole-Population Genome Analysis Provides Insights into Species Evolution and Dispersal

The emergence of distinct populations of Cryptococcus gattii in the temperate North American Pacific Northwest (PNW) was surprising, as this species was previously thought to be confined to tropical and semitropical regions. Beyond a new habitat niche, the dominant emergent population displayed increased virulence and caused primary pulmonary disease, as opposed to the predominantly neurologic disease seen previously elsewhere. Whole-genome sequencing was performed on 118 C. gattii isolates, including the PNW subtypes and the global diversity of molecular type VGII, to better ascertain the natural source and genomic adaptations leading to the emergence of infection in the PNW. Overall, the VGII population was highly diverse, demonstrating large numbers of mutational and recombinational events; however, the three dominant subtypes from the PNW were of low diversity and were completely clonal. Although strains of VGII were found on at least five continents, all genetic subpopulations were represented or were most closely related to strains from South America. The phylogenetic data are consistent with multiple dispersal events from South America to North America and elsewhere. Numerous gene content differences were identified between the emergent clones and other VGII lineages, including genes potentially related to habitat adaptation, virulence, and pathology. Evidence was also found for possible gene introgression from Cryptococcus neoformans var. grubii that is rarely seen in global C. gattii but that was present in all PNW populations. These findings provide greater.IMPORTANCE Cryptococcus gattii emerged in the temperate North American Pacific Northwest (PNW) in the late 1990s. Beyond a new environmental niche, these emergent populations displayed increased virulence and resulted in a different pattern of clinical disease. In particular, severe pulmonary infections predominated in contrast to presentation with neurologic disease as seen previously elsewhere. We employed population-level whole-genome sequencing and analysis to explore the genetic relationships and gene content of the PNW C. gattii populations. We provide evidence that the PNW strains originated from South America and identified numerous genes potentially related to habitat adaptation, virulence expression, and clinical presentation. Characterization of these genetic features may lead to improved diagnostics and therapies for such fungal infections. The data indicate that there were multiple recent introductions of C. gattii into the PNW. Public health vigilance is warranted for emergence in regions where C. gattii is not thought to be endemic

Pathogenic diversity amongst serotype C VGIII and VGIV Cryptococcus gattii isolates

Cryptococcus gattii is one of the causative agents of human cryptococcosis. Highly virulent strains of serotype B C. gattii have been studied in detail, but little information is available on the pathogenic properties of serotype C isolates. In this study, we analyzed pathogenic determinants in three serotype C C. gattii isolates (106.97, ATCC 24066 and WM 779). Isolate ATCC 24066 (molecular type VGIII) differed from isolates WM 779 and 106.97 (both VGIV) in capsule dimensions, expression of CAP genes, chitooligomer distribution, and induction of host chitinase activity. Isolate WM 779 was more efficient than the others in producing pigments and all three isolates had distinct patterns of reactivity with antibodies to glucuronoxylomannan. This great phenotypic diversity reflected in differential pathogenicity. VGIV isolates WM 779 and 106.97 were similar in their ability to cause lethality and produced higher pulmonary fungal burden in a murine model of cryptococcosis, while isolate ATCC 24066 (VGIII) was unable to reach the brain and caused reduced lethality in intranasally infected mice. These results demonstrate a high diversity in the pathogenic potential of isolates of C. gattii belonging to the molecular types VGIII and VGIV

Cryptococcus gattii in North American Pacific Northwest: whole-population genome analysis provides insights into species evolution and dispersal

The emergence of distinct populations of Cryptococcus gattii in the temperate North American Pacific Northwest (PNW) was surprising, as this species was previously thought to be confined to tropical and semitropical regions. Beyond a new habitat niche, the dominant emergent population displayed increased virulence and caused primary pulmonary disease, as opposed to the predominantly neurologic disease seen previously elsewhere. Whole-genome sequencing was performed on 118 C. gattii isolates, including the PNW subtypes and the global diversity of molecular type VGII, to better ascertain the natural source and genomic adaptations leading to the emergence of infection in the PNW. Overall, the VGII population was highly diverse, demonstrating large numbers of mutational and recombinational events; however, the three dominant subtypes from the PNW were of low diversity and were completely clonal. Although strains of VGII were found on at least five continents, all genetic subpopulations were represented or were most closely related to strains from South America. The phylogenetic data are consistent with multiple dispersal events from South America to North America and elsewhere. Numerous gene content differences were identified between the emergent clones and other VGII lineages, including genes potentially related to habitat adaptation, virulence, and pathology. Evidence was also found for possible gene introgression from Cryptococcus neoformans var. grubii that is rarely seen in global C. gattii but that was present in all PNW populations. These findings provide greater understanding of C. gattii evolution in North America and support extensive evolution in, and dispersal from, South America. Importance: Cryptococcus gattii emerged in the temperate North American Pacific Northwest (PNW) in the late 1990s. Beyond a new environmental niche, these emergent populations displayed increased virulence and resulted in a different pattern of clinical disease. In particular, severe pulmonary infections predominated in contrast to presentation with neurologic disease as seen previously elsewhere. We employed population-level whole-genome sequencing and analysis to explore the genetic relationships and gene content of the PNW C. gattii populations. We provide evidence that the PNW strains originated from South America and identified numerous genes potentially related to habitat adaptation, virulence expression, and clinical presentation. Characterization of these genetic features may lead to improved diagnostics and therapies for such fungal infections. The data indicate that there were multiple recent introductions of C. gattii into the PNW. Public health vigilance is warranted for emergence in regions where C. gattii is not thought to be endemic

Multilocus Sequence Typing Reveals Extensive Genetic Diversity of the Emerging Fungal Pathogen Scedosporium aurantiacum

Scedosporium spp. are the second most prevalent filamentous fungi after Aspergillus spp. recovered from cystic fibrosis (CF) patients in various regions of the world. Although invasive infection is uncommon prior to lung transplantation, fungal colonization may be a risk factor for invasive disease with attendant high mortality post-transplantation. Abundant in the environment, Scedosporium aurantiacum has emerged as an important fungal pathogen in a range of clinical settings. To investigate the population genetic structure of S. aurantiacum, a MultiLocus Sequence Typing (MLST) scheme was developed, screening 24 genetic loci for polymorphisms on a tester strain set. The six most polymorphic loci were selected to form the S. aurantiacum MLST scheme: actin (ACT), calmodulin (CAL), elongation factor-1α (EF1α), RNA polymerase subunit II (RPB2), manganese superoxide dismutase (SOD2), and β-tubulin (TUB). Among 188 global clinical, veterinary, and environmental strains, 5 to 18 variable sites per locus were revealed, resulting in 8 to 23 alleles per locus. MLST analysis observed a markedly high genetic diversity, reflected by 159 unique sequence types. Network analysis revealed a separation between Australian and non-Australian strains. Phylogenetic analysis showed two major clusters, indicating correlation with geographic origin. Linkage disequilibrium analysis revealed evidence of recombination. There was no clustering according to the source of the strains: clinical, veterinary, or environmental. The high diversity, especially amongst the Australian strains, suggests that S. aurantiacum may have originated within the Australian continent and was subsequently dispersed to other regions, as shown by the close phylogenetic relationships between some of the Australian sequence types and those found in other parts of the world. The MLST data are accessible at http://mlst.mycologylab.org. This is a joined publication of the ISHAM/ECMM working groups on “Scedosporium/Pseudallescheria Infections” and “Fungal Respiratory Infections in Cystic Fibrosis”.Peer Reviewe

Community-Based Outbreaks in Vulnerable Populations of Invasive Infections Caused by Streptococcus pneumoniae Serotypes 5 and 8 in Calgary, Canada

BACKGROUND: Outbreaks of invasive pneumococcal disease (IPD) typically occur within institutions. Beginning in 2005, we detected an increase in serotype (ST) 5 and ST8 IPD cases, predominantly in homeless persons living in an open community. METHODOLOGY/PRINCIPAL FINDINGS: CASPER (Calgary Area S. pneumoniae Epidemiology Research) surveillance study of all IPD (sterile site isolates) in our region (pop ~1,100,000). Interviews and chart reviews of all cases and all isolates phenotypically analyzed and selected isolated tested by multi-locus sequence typing (MLST). CONCLUSIONS/SIGNIFICANCE: During 2005-2007, 162 cases of ST5 IPD and 45 cases of ST8 IPD were identified. The isolates demonstrated phenotypic and genotypic clonality. The ST5 isolates were sequence type (ST) 289 and demonstrated intermediate susceptibility to TMP-SMX. The ST8 isolates were predominantly ST1268, with a susceptible antimicrobial susceptibility profile. Individuals with ST5 IPD were more likely to be middle aged (OR 2.6), homeless (OR 4.4), using illicit drugs(OR 4.8), and asthmatic(OR 2.6). Those with ST8 were more likely to be male (OR 4.4), homeless (OR 2.6), aboriginal (OR7.3), and a current smoker (OR 2.5). Overlapping outbreaks of ST5 and ST8 IPD occurred in an open community in Calgary, Canada and homelessness was a predominant risk factor. Homelessness represents a unique community in which pneumococcal outbreaks can occur

The status of cryptococcosis in Latin America

Cryptococcosis is a life-threatening fungal infection caused by the encapsulated yeasts Cryptococcus neoformans and C. gattii, acquired from the environment. In Latin America, as occurring worldwide, C. neoformans causes more than 90% of the cases of cryptococcosis, affecting predominantly patients with HIV, while C. gattii generally affects otherwise healthy individuals. In this region, cryptococcal meningitis is the most common presentation, with amphotericin B and fluconazole being the antifungal drugs of choice. Avian droppings are the predominant environmental reservoir of C. neoformans, while C. gattii is associated with several arboreal species. Importantly, C. gattii has a high prevalence in Latin America and has been proposed to be the likely origin of some C. gattii populations in North America. Thus, in the recent years, significant progress has been made with the study of the basic biology and laboratory identification of cryptococcal strains, in understanding their ecology, population genetics, host-pathogen interactions, and the clinical epidemiology of this important mycosis in Latin America.Fil: Firacative, Carolina. University of Sydney; AustraliaFil: Lizarazo, Jairo. Universidad de Pamplona; EspañaFil: Illnait Zaragozí, María Teresa. Tropical Medicine Institute Pedro Kourí; CubaFil: Castañeda, Maria Elizabeth. Instituto Nacional de Salud; Colombia. Latin American Cryptococcal Study Group; BrasilFil: Arechavala, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Córdoba, Susana Beatríz. Latin American Cryptococcal Study Group; Brasil. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Mazza, Mariana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Taverna, Constanza Giselle. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Isla, Guillermina. Latin American Cryptococcal Study Group; Brasil. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Chiapello, Laura Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Latin American Cryptococcal Study Group; BrasilFil: Vergara, Mario León Silva. Universidade Federal do Triangulo Mineiro; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Melhem, Marcia S. C.. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Szeszs, Maria Walderez. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Martins, Marilena dos Anjos. Latin American Cryptococcal Study Group; Brasil. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; BrasilFil: Bonfietti, Lucas Xavier. Latin American Cryptococcal Study Group; Brasil. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; BrasilFil: Oliveira, Rogério Antonio de. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Oliveira, Lidiane de. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Santos, Dayane Christine Silva. Latin American Cryptococcal Study Group; Brasil. Governo do Estado de São Paulo. Secretaria da Saúde. Instituto Adolfo Lutz; BrasilFil: Lazera, Marcia S.. Latin American Cryptococcal Study Group; Brasil. Fundación Oswaldo Cruz; BrasilFil: Wanke, Bodo. Fundación Oswaldo Cruz; Brasil. Latin American Cryptococcal Study Group; BrasilFil: Díaz, María Cristina. Latin American Cryptococcal Study Group; Brasil. Universidad de Chile; ChileFil: Escandón, Patricia. Instituto Nacional de Salud; Colombia. Latin American Cryptococcal Study Group; BrasilFil: Noguera, María Clara. Latin American Cryptococcal Study Group; Brasil. Universidad Metropolitana; ColombiaFil: Andreu, Carlos Manuel Fernández. Latin American Cryptococcal Study Group; BrasilFil: Castril­Lón, Laura. Universidad Nacional Autónoma de México; México. Latin American Cryptococcal Study Group; BrasilFil: Bustamante, Beatriz. Hospital Cayetano Heredia. Instituto de Medicina Tropical Alexander von Humboldt; Perú. Hospital Cayetano Heredia; Perú. Latin American Cryptococcal Study Group; BrasilFil: Dolande, Maribel. Universidad Central de Venezuela; Venezuela. Latin American Cryptococcal Study Group; BrasilFil: Ferrara, Giussepe. Universidad Central de Venezuela; Venezuela. Latin American Cryptococcal Study Group; Brasi

MALDI-TOF MS Enables the Rapid Identification of the Major Molecular Types within the Cryptococcus neoformans/C. gattii Species Complex

BACKGROUND: The Cryptococcus neoformans/C. gattii species complex comprises two sibling species that are divided into eight major molecular types, C. neoformans VNI to VNIV and C. gattii VGI to VGIV. These genotypes differ in host range, epidemiology, virulence, antifungal susceptibility and geographic distribution. The currently used phenotypic and molecular identification methods for the species/molecular types are time consuming and expensive. As Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) offers an effective alternative for the rapid identification of microorganisms, the objective of this study was to examine its potential for the identification of C. neoformans and C. gattii strains at the intra- and inter-species level. METHODOLOGY: Protein extracts obtained via the formic acid extraction method of 164 C. neoformans/C. gattii isolates, including four inter-species hybrids, were studied. RESULTS: The obtained mass spectra correctly identified 100% of all studied isolates, grouped each isolate according to the currently recognized species, C. neoformans and C. gattii, and detected potential hybrids. In addition, all isolates were clearly separated according to their major molecular type, generating greater spectral differences among the C. neoformans molecular types than the C. gattii molecular types, most likely reflecting a closer phylogenetic relationship between the latter. The number of colonies used and the incubation length did not affect the results. No spectra were obtained from intact yeast cells. An extended validated spectral library containing spectra of all eight major molecular types was established. CONCLUSIONS: MALDI-TOF MS is a rapid identification tool for the correct recognition of the two currently recognized human pathogenic Cryptococcus species and offers a simple method for the separation of the eight major molecular types and the detection of hybrid strains within this species complex in the clinical laboratory. The obtained mass spectra provide further evidence that the major molecular types warrant variety or even species status

Caracterización molecular de aislamientos invasores colombianos de Streptococcus pneumoniae serotipo 5, recuperados entre 1994 y 2004

Streptococcus pneumoniae serotipo 5 es una causa importante de enfermedad invasiva en Colombia. Estudios preliminares han demostrado la circulación de un clon reconocido por la red de epidemiología molecular de neumococo (PMEN) como clon 19-Colombia5, susceptible a penicilina pero asociado con resistencia a tetraciclina y cloranfenicol. Con el objetivo de establecer las relaciones genéticas de aislamientos invasores de S. pneumoniae serotipo 5 recuperados en Colombia entre 1994 y 2004, con el clon 19-Colombia5, se estudiaron 83 aislamientos, que tenían datos de susceptibilidad a penicilina, vancomicina, ceftriaxona, eritromicina, trimetoprim sulfametoxazol, cloranfenicol y tetraciclina, de los cuales, 29 fueron recuperados de niños menores de cinco años. Se les determinó el patrón de restricción por electroforesis de campo pulsado (PFGE), usando la enzima Sma I. La similitud genética entre los aislamientos y el clon se estableció según los criterios de Tenover utilizando el programa Fingerprinting‰ II para la generación de dendrogramas. Todos los aislamientos se agruparon en el patrón electroforético A, del cual se derivaron 18 subtipos, todos relacionados con el clon 19-Colombia5. El patrón A se estableció en 32 aislamientos (38,6%), el subtipo A8 en 18 (21,7%) y el A5 en 10 (12%), los patrones restantes agruparon los otros 23 aislamientos. Los 34 aislamientos resistentes a tetraciclina y cloranfenicol, estuvieron relacionados con el patrón electroforético A (n=32) y los subtipos A16 (n=1) y A28 (n=1), caracterizados por presentar una banda de 340 Kb, al igual que el clon. Estos resultados muestran la prevalencia y circulación continua de aislamientos de S. pneumoniae serotipo 5, los cuales están genéticamente relacionados con el clon 19-Colombia