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Published on: April 18, 2019
Emergence of linezolid-resistant Staphylococcus epidermidis in the tertiary children's hospital in Cracow, Poland
Maja Kosecka-Strojek1, Ewa Sadowy2, Iwona Gawryszewska2
1Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland.
Insights
Linezolid-resistant Staphylococcus epidermidis strains are a growing threat, especially in vulnerable patients. Genetic analysis revealed specific mutations and genes responsible for this resistance, highlighting the need for monitoring and prevention.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, are opportunistic pathogens affecting immunocompromised individuals and neonates.
- Increasing antibiotic resistance, especially linezolid resistance (LRSE), is a significant global health concern, with LRSE strains emerging in Europe since 2014.
Purpose of the Study:
- To genetically characterize 11 linezolid-resistant Staphylococcus epidermidis isolates recovered from pediatric patients in Poland.
- To investigate the molecular mechanisms underlying linezolid resistance and multidrug resistance in these strains.
Main Methods:
- Species identification using 16S rRNA sequencing and RFLP of the saoC gene.
- Phenotypic characterization of antimicrobial resistance patterns.
- Molecular analyses including PFGE, MLST, SCCmec typing, ica operon detection, and antimicrobial resistance determinant analysis.
Main Results:
- All 11 isolates were multidrug-resistant, including methicillin resistance, and displayed the PhLOPSA phenotype.
- PFGE analysis indicated clonal relatedness among most isolates, identified as ST2 and harboring the ica operon for biofilm formation.
- Linezolid resistance was linked to an A157R mutation in ribosomal protein L3 and the presence of the cfr gene. Novel SCCmec cassette element composition was observed.
Conclusions:
- The study identified specific genetic determinants (A157R mutation, cfr gene) contributing to linezolid resistance in Staphylococcus epidermidis.
- The prevalence of multidrug-resistant, biofilm-forming ST2 strains underscores the threat posed by LRSE in pediatric populations.
- Enhanced surveillance, infection prevention programs, and monitoring of linezolid-resistant strains are crucial to mitigate risks in clinical settings.
Abstract:
Coagulase-negative staphylococci, ubiquitous commensals of human skin, and mucous membranes represent important pathogens for immunocompromised patients and neonates. The increasing antibiotic resistance among Staphylococcus epidermidis is an emerging problem worldwide. In particular, the linezolid-resistant S. epidermidis (LRSE) strains are observed in Europe since 2014. The aim of our study was to genetically characterize 11 LRSE isolates, recovered mostly from blood in the University Children's Hospital in Krakow, Poland, between 2015 and 2017. For identification of the isolates at the species level, we used 16S rRNA sequencing and RFLP of the saoC gene. Isolates were characterized phenotypically by determining their antimicrobial resistance patterns and using molecular methods such as PFGE, MLST, SCCmec typing, detection of the ica operon, and analysis of antimicrobial resistance determinants. All isolates were multidrug-resistant, including resistance to methicillin, and exhibited so-called PhLOPSA phenotype. In PFGE, all isolates (excluding one from a catheter) represented identical patterns, were identified as ST2, and harbored the ica operon, responsible for biofilm formation. Linezolid resistance was associated with acquisition of A157R mutation in the ribosomal protein L3 and the presence of cfr gene. All isolates revealed new SCCmec cassette element composition. Recently, pediatric patients with serious staphylococcal infections are often treated with linezolid. The increasing linezolid resistance in bacterial strains becomes a real threat for patients, and monitoring such infections combined with surveillance and infection prevention programs is very important to decrease number of linezolid-resistant staphylococcal strains.
