Cystic fibrosis (CF) is one of the most common genetic lung diseases worldwide. The production of sticky viscous mucus leads to enhanced bacterial colonization and infection, but yeasts and filamentous fungi are also found abundantly in the mucus of patients suffering from CF. The role of fungi in the airways of CF patients is still not understood completely. Furthermore, recent investigations have shown that the spectrum of fungi isolated from the airways of CF patients depends strongly on the methods used. In this study, different mycological culture methods were compared: culture with a native inoculum, culture with homogenization of CF sputum, and culture after homogenization and serial dilutions of CF sputum. Altogether, 934 sputum samples from 113 patients were examined from July 2009 through December 2011. A total of 1,744 fungal isolates was recovered; 20 different yeasts and 14 filamentous fungal species were identified. Candida albicans, C. dubliniensis, and C. parapsilosis were the most common species of yeast. For the filamentous fungi, Aspergillus fumigatus was the most common, followed by Scedosporium apiospermum/Pseudallescheria boydii group and A. terreus. Many fungal, species such as Exophiala dermatitidis, Rasamsonia (Geosmithia) argillacea, and others, were isolated only from homogenized sputum samples. The longitudinal data also show that fungal colonization of CF patients is quite stable, even when treated with itraconazole. In conclusion, we recommend homogenizing CF sputa with a mucolyticum, to prepare serial dilutions, and to use appropriate fungal culture media with added antibiotics.
Cystic fibrosis (CF) is the most common hereditary lung disease in the Caucasian population, characterized by viscous bronchial secretion, consecutive defective mucociliary clearance, and unavoidable colonization with microorganisms. Besides
Pseudomonas
aeruginosa
,
Staphylococcus
aureus
is the most common bacterial species colonizing the CF respiratory tract. Under antibiotic pressure
S.
aureus
is able to switch to small colony variants (SCV). These small colony variants can invade epithelial cells, overcome antibiotic therapy inside the cells and can be the starting point for extracellular recolonization. The aim of the present study was the isolation and characterization of
S. aureus
small colony variants from Austrian cystic fibrosis patients. Samples collected from 147 patients were screened for the presence of
S. aureus
wild-type and small colony variants. Antibiotic susceptibility testing and determination of the small colony variants causing auxotrophism were performed. Wild-type isolates were assigned to corresponding small colony variants with spa typing. In total, 17 different small colony variant isolates and 12 corresponding wild-type isolates were obtained. 13 isolates were determined thymidine auxotroph, 2 isolates were auxotroph for hemin, and none of the tested isolates was auxotroph for both, respectively. The presence of SCVs is directly related to a poor clinical outcome, therefore a monitoring of SCV prevalence is recommended. This study revealed rather low SCV ratios in CF patients compared to other countries.
After intestinal colonization with extended-spectrum β-lactamase-producing enterobacteriaceae at the neonatal ICU, infants potentially remain carriers during the first year after discharge. Intrafamilial spread has been proven.
Background: Cystic fibrosis (CF) is the most common life-limiting inherited disease in Caucasian populations. While pathological changes can be seen in various organs, morbidity and mortality are mainly related to the respiratory tract, with patients suffering from chronic bronchopulmonary infections with characteristic pathogens including Staphylococcus aureus.Objectives: To date, there is only very limited data on the genetic and phenotypic characteristics of S. aureus in CF patients. Therefore, in our study, we characterized 58 S. aureus isolates collected from CF patients in Austria by spa typing, DNA microarray profiling, as well as antimicrobial susceptibility testing in order to determine common genomic and antimicrobial resistance features. The tested strain collection exhibited high genomic diversity. Results: The 58 isolates were assigned to 16 clonal complexes and 48 spa types and differed greatly regarding their virulence and resistance gene profiles. The predominant clonal complexes were MLST CC30 (22%), CC15 (16%), CC45 (14%), and CC5 (12%), complexes that are highly prevalent worldwide among S. aureus strains isolated from humans colonized or infected with S. aureus. DNA microarray profiles showed a wide variety of genes encoding antimicrobial resistance and virulence factors such as various leukocidins, haemolysins, enterotoxins, exfoliative toxins, toxic shock syndrome toxin, as well as genes involved in adhesion and immune evasion. Conclusions: While a large number of strains exhibited resistance to one or several antimicrobial agents, methicillin-resistant S. aureus was found at a low prevalence of 3% (n = 2) only. The two methicillin-resistant S. aureus isolates were assigned to CC152/t355 (SCCmecV) and CC5/t001 (SCCmecI). This is the first study to genetically characterize S. aureus isolates in CF patients in Austria.
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