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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
Methicillin resistance and virulence genes in invasive and nasal Staphylococcus epidermidis isolates from neonates
Vivian Carolina Salgueiro1, Natalia Lopes Pontes Iorio2, Marcelle Cristina Ferreira1
1Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Av Carlos Chagas Filho, no 373, CCS, Bloco I, Sala 010, Cidade Universitária, Rio de Janeiro, Brazil.
Background:
Staphylococcus epidermidis is an opportunistic pathogen involved in hospital-acquired infections, particularly in those related to medical devices. This study characterized 50 genetically unrelated S. epidermidis isolates from bloodstream infections (BSIs, n = 31) and nares (n = 19) of neonates in relation to staphylococcal chromosomal cassette mec (SCCmec) type, biofilm production and associated genes, and the arginine catabolic mobile elements (ACME), in order to detect virulence factors that could discriminate a potential invasiveness isolate or predict an increasing pathogenicity.
Results:
Isolates from both groups showed no difference for biofilm production and ACME genes detection. However, BSI isolates harbored more frequently the sdrF and sesI genes (p < 0.05), whereas biofilm producer isolates were associated with presence of the aap gene. The sdrF gene was also significantly more in the biofilm producer isolates from BSI. The SCCmec type IV and the ccr2 complex were related to BSI isolates (p < 0.05), while 83% of the nasal isolates were non-typeable for the SCCmec elements, with the mec complex and ccr undetectable as the most frequent profile.
Conclusions:
Despite the great clonal diversity displayed by S. epidermidis isolates from neonates, BSI isolates harbored more frequently the sdrF and sesI adhesin genes, while nasal isolates were very variable in SCCmec composition. These aspects could be advantageous to improve colonization in the host increasing its pathogenicity.
Insights
Staphylococcus epidermidis bloodstream infection isolates from neonates more frequently carried specific adhesin genes (sdrF, sesI) and SCCmec type IV, suggesting increased pathogenicity compared to nasal isolates.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Staphylococcus epidermidis is a key cause of hospital-acquired infections, especially those linked to medical devices.
- Neonatal bloodstream infections (BSIs) and nasal colonization by S. epidermidis are significant clinical concerns.
- Understanding virulence factors is crucial for predicting S. epidermidis pathogenicity.
Purpose of the Study:
- To characterize S. epidermidis isolates from neonatal BSIs and nares.
- To investigate the association of staphylococcal chromosomal cassette mec (SCCmec) type, biofilm production, and arginine catabolic mobile elements (ACME) with infection source.
- To identify virulence factors differentiating invasive S. epidermidis isolates.
Main Methods:
- Genomic analysis of 50 genetically distinct S. epidermidis isolates from neonatal BSIs (n=31) and nares (n=19).
- Assessment of staphylococcal chromosomal cassette mec (SCCmec) types, biofilm production, and arginine catabolic mobile elements (ACME).
- Detection of specific virulence genes including sdrF, sesI, and aap.
Main Results:
- No significant differences in biofilm production or ACME genes between BSI and nasal isolates.
- BSI isolates more frequently harbored sdrF and sesI genes (p<0.05).
- SCCmec type IV and ccr2 complex were associated with BSI isolates; 83% of nasal isolates were non-typeable for SCCmec.
Conclusions:
- Neonatal S. epidermidis isolates exhibit significant clonal diversity.
- The presence of sdrF and sesI adhesin genes in BSI isolates may contribute to increased pathogenicity.
- Variability in SCCmec composition of nasal isolates warrants further investigation.
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