Local circulating clones of Staphylococcus aureus in Ecuador

Area of Science:

• Medical Microbiology
• Epidemiology
• Infectious Diseases

Background:

• Pandemic Staphylococcus aureus clones, particularly methicillin-resistant S. aureus (MRSA), require continuous surveillance for accurate epidemiological analysis.
• While the USA300 Latin American variant clone (USA300-LV) is known in Ecuador, data on other circulating MRSA strains are limited.

Purpose of the Study:

• To identify the sequence types (ST) of Staphylococcus aureus strains circulating in Quito, Ecuador, using a 14-locus Multiple-Locus Variable number tandem repeat Analysis (MLVA) genotyping approach.
• To characterize the epidemiological landscape of MRSA and methicillin-susceptible S. aureus (MSSA) in clinical settings within Quito.

Main Methods:

• Analysis of 132 S. aureus strains isolated between 2005 and 2013 from various clinical settings in Quito, Ecuador.
• Utilized a 14-locus MLVA genotyping method for sequence typing (ST) of the isolates.
• MRSA isolates constituted 46.97% (62/132) of the total S. aureus population studied.

Main Results:

• Identified the prevalent USA300-LV clone (ST8-MRSA-IV, Panton-Valentine Leukocidin [PVL] +) in 37 MRSA isolates.
• Detected other MRSA clones including the Brazilian clone (ST239-MRSA-III, PVL-), New York/Japan clone (ST5-MRSA-II, PVL-), Pediatric clone (ST5-MRSA-IV, PVL-), USA600 clone (ST45-MRSA-II, PVL-), and UK-EMRSA-15 clone (ST22-MRSA-IV, PVL-).
• Identified prevalent MSSA STs as ST8, ST45, ST30, ST5, and ST22, and detected a livestock-associated clone (ST398) in a hospital environment.

Conclusions:

• Quito exhibits a diverse MRSA landscape beyond the prevalent USA300-LV clone, including the Brazilian, Pediatric, and New York/Japan clones.
• The study reports the first detection of USA600 and UK-EMRSA-15 clones in Ecuador.
• Evidence of the livestock-associated S. aureus clone ST398 was found in a hospital setting, highlighting potential transmission pathways.