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Microsatellite typing to trace Aspergillus flavus infections in a hematology unit
Inès Hadrich1, Fattouma Makni, Ali Ayadi
1Laboratoire de Biologie Moléculaire Parasitaire et Fongique, Faculté de Médecine de Sfax, Sfax, Tunisia.
Abstract:
Assessing the relatedness of strains isolated from patients and their environment is instrumental in documenting the source of preventable health care-associated life-threatening Aspergillus flavus human infection clusters. The present study aimed at identifying and selecting suitable microsatellite markers for A. flavus typing. This typing scheme was then applied to investigate the A. flavus epidemiology within a hematology unit in Sfax, Tunisia. Use of a combination of five markers made it possible to discern clusters of isolates and to substantiate the genetic diversity of A. flavus within clusters. Isolates from Tunisia and Marseille, France, displayed distinct haplotypes, indicating a highly significant geographical structuring of A. flavus. The typing of clinical and environmental A. flavus isolates in a hematology unit provided insights into its hospital epidemiology. From a heterogeneous genetic background, a cluster indicative of a clonal propagation episode within the unit could be identified. In two patients with invasive aspergillosis, the same genotype was found in clinical and environmental isolates, indicating hospital-acquired colonization and infection. In further studies, this novel microsatellite typing scheme might be instrumental in illuminating important epidemiological issues about A. flavus population genetics or epidemiology, including tracing the sources and routes of transmission.
Insights
This study developed microsatellite markers to track Aspergillus flavus infections. The new method identified infection sources in a hospital, revealing clonal spread and hospital-acquired cases.
Area of Science:
- Medical Mycology
- Molecular Epidemiology
- Infectious Disease Control
Background:
- Healthcare-associated infections (HAIs) caused by Aspergillus flavus pose significant risks, particularly in immunocompromised patients.
- Accurate strain typing is crucial for identifying infection sources and preventing outbreaks of life-threatening Aspergillus flavus clusters.
- Existing typing methods may lack the discriminatory power needed for detailed epidemiological investigations.
Purpose of the Study:
- To identify and select robust microsatellite markers for typing Aspergillus flavus.
- To investigate the epidemiology of Aspergillus flavus within a hematology unit.
- To trace the sources and transmission routes of Aspergillus flavus in a hospital setting.
Main Methods:
- Development and validation of a microsatellite typing scheme using five distinct markers.
- Application of the typing scheme to clinical and environmental Aspergillus flavus isolates from a hematology unit in Sfax, Tunisia.
- Comparative analysis of isolates from Tunisia and Marseille, France, to assess geographical structuring.
Main Results:
- The five-marker microsatellite scheme effectively discerned Aspergillus flavus isolate clusters and revealed genetic diversity.
- Distinct haplotypes were observed between Tunisian and French isolates, indicating significant geographical structuring.
- Evidence of clonal propagation within the hematology unit was identified, alongside direct links between clinical and environmental isolates in two invasive aspergillosis cases.
Conclusions:
- The novel microsatellite typing scheme is a valuable tool for investigating Aspergillus flavus epidemiology in healthcare settings.
- The study successfully identified hospital-acquired colonization and infection, providing insights into transmission dynamics.
- This method holds promise for future studies on Aspergillus flavus population genetics and outbreak investigations.
