High biofilm production by invasive multiresistant staphylococci

Area of Science:

• Microbiology
• Infectious Diseases
• Molecular Epidemiology

Background:

• Staphylococci form biofilms, leading to opportunistic and invasive infections, particularly catheter-related ones.
• Controlling infection spread necessitates early detection of pathogenic strains and understanding their transferable resistance cassettes.

Purpose of the Study:

• To evaluate biofilm formation in staphylococci.
• To perform SCCmec (Staphylococcal Cassette Chromosome mec) typing on staphylococcal isolates.

Main Methods:

• Biofilm production assessed using a semi-quantitative microtiter plate method.
• SCCmec typing (types I-V) performed via multiplex PCR.
• Isolates categorized as invasive (n=74) or colonizing (n=30) based on clinical criteria.

Main Results:

• Biofilm formation was significantly higher in invasive (89%) versus colonizing (64%) isolates (p < 0.05).
• Invasive isolates showed significant differences in SCCmec types IV or V compared to colonizing isolates (p < 0.05).
• No correlation was found between biofilm intensity and specific SCCmec types.

Conclusions:

• Biofilm formation and SCCmec typing are relevant for understanding staphylococcal pathogenicity.
• The spread of SCCmec elements contributes to antimicrobial resistance evolution in biofilm-forming staphylococci.
• Further research into antimicrobial resistance in these strains is warranted.