scholarly journals Genetic and virulence variation in an environmental population of the opportunistic pathogen Aspergillus fumigatus

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 742-751 ◽  
Author(s):  
Fadwa Alshareef ◽  
Geoffrey D. Robson
Keyword(s):  
Aspergillus Fumigatus ◽  
Galleria Mellonella ◽  
Rapd Analysis ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Environmental Isolates ◽  
Pathogenic Potential ◽  
Patient Infection ◽  
Selection Of ◽  
Virulence Variation

Environmental populations of the opportunistic pathogen Aspergillus fumigatus have been shown to be genotypically diverse and to contain a range of isolates with varying pathogenic potential. In this study, we combined two RAPD primers to investigate the genetic diversity of environmental isolates from Manchester collected monthly over 1 year alongside Dublin environmental isolates and clinical isolates from patients. RAPD analysis revealed a diverse genotype, but with three major clinical isolate clusters. When the pathogenicity of clinical and Dublin isolates was compared with a random selection of Manchester isolates in a Galleria mellonella larvae model, as a group, clinical isolates were significantly more pathogenic than environmental isolates. Moreover, when relative pathogenicity of individual isolates was compared, clinical isolates were the most pathogenic, Dublin isolates were the least pathogenic and Manchester isolates showed a range in pathogenicity. Overall, this suggests that the environmental population is genetically diverse, displaying a range in pathogenicity, and that the most pathogenic strains from the environment are selected during patient infection.

scholarly journals Robust, Comprehensive Molecular, and Phenotypical Characterisation of Atypical Candida albicans Clinical Isolates From Bogotá, Colombia

2020 ◽  
Vol 10 ◽  
Author(s):  
Giovanni Rodríguez-Leguizamón ◽  
Andrés Ceballos-Garzón ◽  
Carlos F. Suárez ◽  
Manuel A. Patarroyo ◽  
Claudia M. Parra-Giraldo
Keyword(s):  
Candida Albicans ◽  
Galleria Mellonella ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
High Genetic Diversity ◽  
Cluster Membership ◽  
Protein Mass ◽  
Molecular Tests ◽  
Well Differentiated ◽  
Clade 1

Candida albicans is commensal in human microbiota and is known to be the commonest opportunistic pathogen, having variable clinical outcomes that can lead to up to 60% mortality. Such wide clinical behaviour can be attributed to its phenotypical plasticity and high genetic diversity. This study characterised 10 Colombian clinical isolates which had already been identified as C. albicans by molecular tests; however, previous bioinformatics analysis of protein mass spectra and phenotypical characteristics has shown that this group of isolates has atypical behaviour, sharing characteristics of both C. africana and C. albicans. This study was aimed at evaluating atypical isolates’ pathogenic capability in the Galleria mellonella model; susceptibility profiles were determined and MLST was used for molecular characterisation. Cluster analysis, enabling unbiased bootstrap to classify the isolates and establish their cluster membership and e-BURST, was used for establishing clonal complexes (CC). Both approaches involved using representative MLST data from the 18 traditional C. albicans clades, as well as C. albicans-associated and minor species. Ten atypical isolates were distributed as follows: 6/10 (B71, B41, B60, R6, R41, and R282) were grouped into a statistically well-supported atypical cluster (AC) and constituted a differentiated CC 6; 2/10 of the isolates were clearly grouped in clade 1 and were concurrent in CC 4 (B80, B44). Another 2/10 atypical isolates were grouped in clade 10 and concurred in CC 7 (R425, R111); most atypical isolates were related to geographically distant isolates and some represented new ST. Isolates B41 and R41 in the AC had greater virulence. Isolate B44 was fluconazole-resistant and was grouped in clade 1. The atypical nature of the isolates studied here was demonstrated by the contrast between phenotypical traits (C. africana-like), molecular markers (C. albicans-like), virulence, and antifungal resistance, highlighting the widely described genetic plasticity for this genus. Our results showed that the atypical isolates forming well-differentiated groups belonged to C. albicans. Our findings could contribute towards developing molecular epidemiology approaches for managing hospital-acquired infection.

scholarly journals Phylogenetic Analysis ofStenotrophomonasspp. Isolates Contributes to the Identification of Nosocomial and Community-Acquired Infections

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Vinicius Godoy Cerezer ◽  
Silvia Yumi Bando ◽  
Jacyr Pasternak ◽  
Marcia Regina Franzolin ◽  
Carlos Alberto Moreira-Filho
Keyword(s):  
Phylogenetic Analysis ◽  
Multidrug Resistance ◽  
Phylogenetic Profile ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Environmental Distribution ◽  
Pathogenic Potential ◽  
Clinical Strains ◽  
Specific Fragment ◽  
Clonal Variability

Stenotrophomonasssp. has a wide environmental distribution and is also found as an opportunistic pathogen, causing nosocomial or community-acquired infections. One species,S. maltophilia, presents multidrug resistance and has been associated with serious infections in pediatric and immunocompromised patients. Therefore, it is relevant to conduct resistance profile and phylogenetic studies in clinical isolates for identifying infection origins and isolates with augmented pathogenic potential. Here, multilocus sequence typing was performed for phylogenetic analysis of nosocomial isolates ofStenotrophomonasspp. and, environmental and clinical strains ofS. maltophilia. Biochemical and multidrug resistance profiles of nosocomial and clinical strains were determined. The inferred phylogenetic profile showed high clonal variability, what correlates with the adaptability process ofStenotrophomonasto different habitats. Two clinical isolates subgroups ofS. maltophiliasharing high phylogenetic homogeneity presented intergroup recombination, thus indicating the high permittivity to horizontal gene transfer, a mechanism involved in the acquisition of antibiotic resistance and expression of virulence factors. For most of the clinical strains, phylogenetic inference was made using only partialppsA gene sequence. Therefore, the sequencing of just one specific fragment of this gene would allow, in many cases, determining whether the infection withS. maltophiliawas nosocomial or community-acquired.

scholarly journals INCIDENCE OF BROODER PNEUMONIA AND GENOTYPING ASPERGILLUS FUMIGATUS IN BROILER FARMS IN SULAIMNAIYAH

2021 ◽  
Vol 52 (3) ◽  
pp. 527-534
Author(s):  
B. A. Mahmood ◽  
B. M. Al-Jaff
Keyword(s):  
Aspergillus Fumigatus ◽  
Incidence Rate ◽  
Microsatellite Dna ◽  
Clinical Isolates ◽  
Dna Repeats ◽  
Post Mortem ◽  
Environmental Isolates ◽  
Causative Agents ◽  
Short Tandem

Brooder pneumonia is aspergillosis occurs in chicks caused by Aspergillus fumigatus during the first-week post-hatching. It has not been confirmed yet that all A. fumigatus strains cause brooder pneumonia or it restricted to pathogenic strains. From an outbreak included 28 broiler farms in Sulaimaniyah province, 575 dead and sick chicks were randomly selected, diagnosed clinically, histopathologically, and by post-mortem isolation of A. fumigatus, among them 321 chicks were confirmed to be infected by aspergillosis with incidence rate of (57.5 %). Twenty eight clinical isolates of A. fumigatus along with 15 farm environment isolates represented all the farms were subjected to genotyping through (CA)n and (CACCAC)n short tandem microsatellite DNA repeats. All clinical and environmental isolates were highly polymorphic except two clinical isolates from two different farms which were with the same genotype. It could be concluded that all A. fumigatus strains are potential causative agents of brooder pneumonia.

Distribution of Epidemic Clonal Genetic Markers among Listeria monocytogenes 4b Isolates

2007 ◽  
Vol 70 (3) ◽  
pp. 574-581 ◽  
Author(s):  
GIOVANNA FRANCIOSA ◽  
CONCETTA SCALFARO ◽  
ANTONELLA MAUGLIANI ◽  
FRANCESCA FLORIDI ◽  
ANTONIETTA GATTUSO ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Genetic Markers ◽  
Pulsed Field Gel Electrophoresis ◽  
Genomic Diversity ◽  
Clinical Isolates ◽  
Specific Marker ◽  
Environmental Isolates ◽  
Environmental Persistence ◽  
Pathogenic Potential ◽  
Serotype 4B

Recent genome sequencing of isolates of Listeria monocytogenes serotype 4b implicated in some major outbreaks of foodborne listeriosis has revealed unique genetic markers in these isolates. The isolates were grouped into two distinct epidemic clones, ECI and ECII. In the present study, selected ECI- and ECII-specific genetic markers were detected in 16 and 15 of 89 L. monocytogenes 4b isolates, respectively. The ECI markers were found in 6 of 34 clinical isolates, 9 of 50 food isolates, and 1 of 5 environmental isolates, and the ECII markers were detected in 7 of 34 clinical isolates, 7 of 50 food isolates, and 1 of 5 environmental isolates. Hence, of the isolates with the epidemic clonal genetic markers, 38% (13 of 34) were of clinical origin, 32% (16 of 50) were of food origin, and 40% (2 of 5) were of environmental origin. The predominance of the epidemic clonal markers among the clinical and environmental isolates supports the hypothesis that these markers are correlated with the pathogenic potential of strains and with their environmental persistence. Several isolates had only one epidemic clonal marker, either the ECI-specific marker 133 or the ECII-specific marker 4bSF18. Pulsed-field gel electrophoresis analysis revealed higher genomic diversity among the strains with ECII-like characteristics than among those strains carrying the ECI-specific genetic markers.

scholarly journals Measuring intraspecific variation in the response of clinical isolates of Aspergillus fumigatus to oxidative stress.

2019 ◽  
Author(s):  
Sam El-Kamand ◽  
Carl Ramirez ◽  
Catriona Halliday ◽  
Sharon C-A. Chen ◽  
Charles Oliver Morton
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Uv Light ◽  
Pathogenic Fungus ◽  
Clinical Isolates ◽  
Complex Interplay ◽  
Pathogenic Potential ◽  
Increased Sensitivity

Abstract Objective In this study, the survival of clinical isolates of the pathogenic fungus Aspergillus fumigatus against the oxidative stressors, hydrogen peroxide and menadione, and UV light, was examined to see if there was variation between isolates and if the variation was linked to virulence. Results Fifteen isolates were tested, five from cases of invasive aspergillosis (IA isolates) and ten from cases where the fungus had colonised a patient (colonising isolates). Exposure to UV light and hydrogen peroxide did not show significant differences between the groups of isolates. Colonising isolates showed a trend for greater survival when treated with hydrogen peroxide, mean survival 18.9%, compared to IA isolates, mean survival 8%. Treatment with 50mM menadione confirmed this trend in colonising isolates with an average conidial survival of 72% compared to 50% in IA isolates. Overall significant sensitivity to 50mM menadione was observed in 1/10 colonising isolates compared to 4/5 IA isolates. Increased sensitivity to oxidative stress in IA isolates may seem counterintuitive but could be utilised as an indicator of pathogenic potential in isolates of the fungus and be used in further studies to unravel the complex interplay between host and pathogen.

scholarly journals Insertion sequences drive the emergence of a highly adapted human pathogen

2020 ◽  
Vol 6 (9) ◽  
Author(s):  
Erwin Sentausa ◽  
Pauline Basso ◽  
Alice Berry ◽  
Annie Adrait ◽  
Gwendoline Bellement ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Opportunistic Pathogen ◽  
Insertion Sequences ◽  
Pathogenic Potential ◽  
Highly Pathogenic ◽  
Type Iv ◽  
Genome Wide ◽  
Outer Membrane Porin ◽  
Specific Antigens ◽  
Different Levels

Pseudomonas aeruginosa is a highly adaptive opportunistic pathogen that can have serious health consequences in patients with lung disorders. Taxonomic outliers of P. aeruginosa of environmental origin have recently emerged as infectious for humans. Here, we present the first genome-wide analysis of an isolate that caused fatal haemorrhagic pneumonia. In two clones, CLJ1 and CLJ3, sequentially recovered from a patient with chronic pulmonary disease, insertion of a mobile genetic element into the P. aeruginosa chromosome affected major virulence-associated phenotypes and led to increased resistance to the antibiotics used to combat the infection. Comparative genome, proteome and transcriptome analyses revealed that this ISL3-family insertion sequence disrupted the genes for flagellar components, type IV pili, O-specific antigens, translesion polymerase and enzymes producing hydrogen cyanide. Seven-fold more insertions were detected in the later isolate, CLJ3, than in CLJ1, some of which modified strain susceptibility to antibiotics by disrupting the genes for the outer-membrane porin OprD and the regulator of β-lactamase expression AmpD. In the Galleria mellonella larvae model, the two strains displayed different levels of virulence, with CLJ1 being highly pathogenic. This study revealed insertion sequences to be major players in enhancing the pathogenic potential of a P. aeruginosa taxonomic outlier by modulating both its virulence and its resistance to antimicrobials, and explains how this bacterium adapts from the environment to a human host.

scholarly journals Azole Resistance of Environmental and Clinical Aspergillus fumigatus Isolates from Switzerland

2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Arnaud Riat ◽  
Jérôme Plojoux ◽  
Katia Gindro ◽  
Jacques Schrenzel ◽  
Dominique Sanglard
Keyword(s):  
Aspergillus Fumigatus ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Resistant Isolate ◽  
Azole Resistance ◽  
Clinical Settings ◽  
Content Type ◽  
Azole Antifungals ◽  
First Time

ABSTRACT Aspergillus fumigatus is a ubiquitous opportunistic pathogen. This fungus can acquire resistance to azole antifungals due to mutations in the azole target ( cyp51A ). Recently, cyp51A mutations typical for environmental azole resistance acquisition (for example, TR 34 /L98H) have been reported. These mutations can also be found in isolates recovered from patients. Environmental azole resistance acquisition has been reported on several continents. Here we describe, for the first time, the occurrence of azole-resistant A. fumigatus isolates of environmental origin in Switzerland with cyp51A mutations, and we show that these isolates can also be recovered from a few patients. While the TR 34 /L98H mutation was dominant, a single azole-resistant isolate exhibited a cyp51A mutation (G54R) that was reported only for clinical isolates. In conclusion, our study demonstrates that azole resistance with an environmental signature is present in environments and patients of Swiss origin and that mutations believed to be unique to clinical settings are now also observed in the environment.

Heterogeneity of Environmental, Retail, and Clinical Isolates of Vibrio vulnificus as Determined by Lipopolysaccharide-Specific Monoclonal Antibodies

2001 ◽  
Vol 64 (8) ◽  
pp. 1172-1177 ◽  
Author(s):  
AMY B. ZUPPARDO ◽  
ANGELO DePAOLA ◽  
JOHN C. BOWERS ◽  
KEVIN L. SCHULLY ◽  
JANET A. GOOCH ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Vibrio Vulnificus ◽  
Gulf Coast ◽  
Membrane Surface ◽  
Atlantic Coast ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Environmental Isolates ◽  
Serotype 1 ◽  
Different Seasons

The opportunistic pathogen Vibrio vulnificus expresses lipopolysaccharide (LPS) antigens on its outer membrane surface. A serological typing system was developed for these antigens, utilizing the discriminatory recognition of monoclonal antibodies (MAb) by ELISA. MAb were used to recognize five unique types of LPS-associated antigens for examination of clinical, environmental, and retail isolates of V. vulnificus. The overall serotype profile of the clinical isolates was significantly different (P < 0.05) from that of the environmental and retail isolates. A higher percentage of clinical isolates were typable (61%) compared to the environmental isolates (41%) and retail isolates (44%). In particular, the percentage of serotype 1/5 among clinical isolates (33%), compared to that of environmental (9%) and retail (4%), was highly significant (P < 0.0001). Among the environmental Gulf Coast isolates, there were differences in the prevalence of serotypes 2 and 3 (P < 0.05), depending on whether isolates were obtained from Louisiana or Alabama harvest sites. There were no statistically significant differences between the serotype profiles of Gulf and Atlantic Coast retail isolates despite the absence of serotype 1/5 from the Atlantic Coast. While some serotype diversity was detected in V. vulnificus isolated during different seasons, from different geographic locations, and at retail versus at harvest, there was no apparent concordance between any of the serotype distributions obtained from oysters versus that isolated clinically. The heterogeneity of environmental isolates and relative homogeneity among clinical isolates suggest that human risk may not be predicted on quantitative exposure alone.

scholarly journals Frequency of Iron Uptake Proteins Related Genes Among Klebsiella pneumoniae Isolates

2020 ◽  
Vol 14 (1) ◽  
pp. 107-112
Author(s):  
Tahereh Elhaki ◽  
Ali Gheysarzadeh ◽  
Nourkhoda Sadeghifard ◽  
Iraj Pakzad ◽  
Ava Behrouzi ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
High Frequency ◽  
Iron Uptake ◽  
Ferric Iron ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Klebsiella Pneumonia ◽  
Immunocompromised Patients ◽  
Environmental Isolates ◽  
Pcr Method

Aims: The present study aimed to evaluate Iron uptake protein-related genes in clinical and environmental Klebsiella pneumoniae isolates. Background: Klebsiella pneumoniae as an opportunistic pathogen cause infections in immunocompromised patients. Iron uptake systems play an important role in the pathogenesis of Klebsiella pneumonia. Objectives: This study was designed to investigate the prevalence of iron uptake coding genes among isolates of Klebsiella pneumonia. Materials and Methods: A total of 300 isolates of Klebsiella pneumonia including 150 clinical isolates and 150 environmental isolates were selected. Finally, the frequency of iroN, iucD, kfuA,hmuR, and ybt [yHPI] genes were detected by PCR method. Results: The frequency of kfuA, iucD, iroN, yHPI in clinical isolates were 33.3%, 16.7%, 24.7%, 15.3%, respectively and these genes among environmental isolates were 20.7%, 6%, 49.3% and 0.7%, respectively. Among the clinical isolates, the most frequency genes were kfuA gene [50 isolates] and after that iroN [37 isolates], iucD [25 isolates] and yHPI [23 isolates], the genes with the most frequency among environmental isolates were iroN gene [74 isolates] and following that kfuA [31 isolates], iucD [9 isolates] and yHPI [1 isolate]. No hmuR positive samples among all clinical or environmental isolates were found. Conclusion: The result of this study showed that because of the high frequency of ferric iron system coding gene kfu among clinical isolates, this system might play an important role in the survival of bacteria against its host.

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