Bacterial infections are responsible for 60–90% of all sinusitis cases. One of the more common bacteria in patients with chronic sinusitis are coagulase negative staphylococci (CoNS).
CoNS are a heterogeneous group of bacteria that colonize the skin and mucous membranes of humans and animals. CoNS are typical saprophytes but become pathogens under certain conditions. Thus, coagulase-negative staphylococci contribute to the occurrence of infection in various locations, symptoms and course.
CoNS are widespread in ENT, especially in patients with chronic sinusitis.
Known in the past as "cutaneous staphylococci," CoNS have been interpreted as companion bacteria or contamination of diagnostic samples. Today, based on reports from advanced microbiological laboratories using molecular diagnostic methods, it is known that CoNS are dangerous pathogens responsible for infections, including nosocomial infections.
In clinical practice, there is a significant patient population with chronic sinusitis who remain refractory to treatment despite its stringent regimens, including surgery and prolonged antibiotic therapy.
Antibiotic-resistant and difficult to eradicate bacteria are the most common bacteria in these patients. Standard therapy based on the sensitivity of microorganisms is not sufficient in such cases. In addition to determining the mechanisms of antibiotic resistance, the properties of microorganisms are also important, including the ability to form biofilms and the presence of microbial virulence (pathogenicity) factors.
Performing an extended antibiogram and accurately determining the minimum inhibitory concentration (MIC) of an antibiotic and linking phenotypic antibiotic resistance with the presence and expression of antibiotic resistance genes in specific bacterial strains will contribute to understanding the mechanisms of the emergence and maintenance of antibiotic resistance. Such analysis is particularly important in patients susceptible to infections, it will allow for more targeted therapy in patients, and will also allow to track the transmission of antibiotic-resistant strains, which in the long run will contribute to lowering antibiotic resistance among bacteria. The information obtained in the course of genetic tests in conjunction with the results of other clinical trials and the interview obtained from the patient will allow for personalized, targeted treatment.