Dozens of diverse types of the bacteria Staphylococcus aureus were identified in the airways of cystic fibrosis (CF) patients, including five new types and one commonly associated with livestock, a study reports.
Findings were reported in the study, “Emergence and spread of worldwide Staphylococcus aureus clones among cystic fibrosis patients, published in the journal Infection and Drug Resistance.
S. aureus are pathogens found in the airways of CF patients that cause respiratory infections. These pathogens are isolated in approximately one-third of patients and sometimes persist throughout their lives.
A high number of isolated S. aureus types are resistant to antimicrobial agents, which kill or stop the growth of these bacteria, including the methicillin-resistant S. aureus (MRSA). This resistance may explain their growing prevalence among CF patients in Europe and the U.S.
It is crucial for scientists to track staphylococcal colonization to reduce the incidence of S. aureus in CF patients and prevent their spread.
In the study, researchers investigated the relationship between different types of S. aureus in CF patients’ airways and their antimicrobial resistance. They also looked at the prevalence of genes associated with the production of toxins.
Participants included 107 CF patients (1 month to 47 years old) treated at the Outpatient Cystic Fibrosis Clinic at Polanki Children’s Hospital in Gdansk, Poland, between 2012 and 2014. A total of 215 S. aureus isolates from throat swabs, sputum, and bronchoalveolar lavage were analyzed for molecular identification, antimicrobial resistance, and toxin genes.
Researchers found 69 types of S. aureus, of which five had never been reported before. A total of 12 (5.6%) MRSA isolates and 102 (47.7%) multidrug-resistant isolates were also identified. These results indicate that S. aureus isolates vary considerably in CF patients.
“CF patients do not seem to be colonized with any unique [S. aureus] type(s), but rather colonized with the types being currently spread in a given population” the researchers wrote.
The S. aureus types identified in the study are in line with the pattern seen in hospitals in Poland.
Regarding the prevalence of toxin genes in S. aureus isolates, researchers found that these also vary considerably in CF patients, with bacteria displaying diverse toxin gene profiles.
According to the team, this study was the first European report documenting the presence of a specific animal-related MRSA type (ST398) in a CF patient. This S. aureus type is commonly found in livestock, and can be associated with invasive lung infections.
“This implies that patients with CF can also be colonized with ST398 MRSA, and justifies constant monitoring of staphylococcal colonization and identification of epidemic S. aureus clones in this group,” the team concluded.