The aim of the study was the molecular characterization of Staphylococcus aureus (S. aureus) from the Caribbean islands of Trinidad, Tobago and Jamaica to gain an up-to-date understanding of the distribution and epidemiology of the genetically diverse bacterial species. More than 100 isolates were isolated from patients with skin and soft tissue infections for this purpose.
Using various DNA sequencing techniques, as well as a microarray-based assay developed by research campus partner INTER-ARRAY by fzmb GmbH (INTER-ARRAY Genotyping Kit S. aureus), the researchers identified and characterized typical S. aureus, as well as closely related S. argenteus strains. Emphasis was placed on the study of antibiotic resistance, virulence factors, and the ability to produce certain toxins. This enabled the classification of the isolates into different S. aureus groups, the so-called clonal complexes.
In almost 40 percent of the isolates examined, the genetic information for the production of Panton-Valentine leukocidin (PVL) was detected. PVL is a toxin that causes damage to white blood cells at the site of infection and thus weakens the immune defense system. The ability to produce PVL is not widespread in S. aureus and can be regarded as a warning sign for significantly increased pathogenicity. Finally, the actual production of the toxin could be detected in almost all (37 of 38 isolates) by means of a novel rapid test (Senova, Weimar, Germany).
With one exception, the PVL-producing S. aureus characterized in the research project showed sensitivity to the antibiotic methicillin. Although this makes it easier to treat a patient compared with methicillin-resistant S. aureus (MRSA), infections of PVL-producing, methicillin-sensitive S. aureus (MSSA) are significantly riskier compared with infections of PVL-negative S. aureus because they can often cause more serious and recurrent infections.
"In the case of skin and soft tissue infections of travelers returning from the Caribbean, physicians should thus consider a possible staphylococcal infection," emphasized Dr. Stefan Monecke, senior scientist in the Optical Molecular Diagnostics and Systems Technology group and first author of the study. In the event of an inpatient admission, testing for S. aureus using a rapid test is recommended in order to initiate prompt and targeted treatment if necessary and to prevent further spread in the hospital.
The study was conducted as part of the InfectoGnostics research projects "ADA" and "ResiCheck", in which detection systems are being developed for the rapid identification and characterization of S. aureus. Part of the work is also part of the basic technologies for the establishment of the Leibniz Center for Photonics in Infection Research.
Link to original publication in Antibiotics: https://doi.org/10.3390/antibiotics12061050
Monecke S, Akpaka PE, Smith MR, Unakal CG, Thoms Rodriguez C-A, Ashraph K, Müller E, Braun SD, Diezel C, Reinicke M, et al. Clonal Complexes Distribution of Staphylococcus aureus Isolates from Clinical Samples from the Caribbean Islands. Antibiotics. 2023; 12(6):1050.