The occurrence of clarithromycin resistance among Helicobacter pylori strains is a major cause of the treatment failure. Resistance to this drug is conferred by point mutations in 23S rRNA gene and the most prevalent mutations are A2143G and A2142G. The aim of the study was to evaluate the occurrence of A2143G and A2142G mutations in a group of H. pylori strains resistant to clarithromycin. The study included 21 clarithromycin-resistant H. pylori strains collected between 2006 and 2009 in southern Poland. Resistance to clarithromycin was quantitatively tested with the E-test to determine the minimal inhibitory concentration (MIC value). The point mutations of H. pylori isolates were detected by PCR followed by RFLP analysis. The MIC values for clarithromycin for the analyzed strains ranged from 1.5 mg/L to 64 mg/L. Nine H. pylori strains exhibited A2143G mutation and A2142G mutation was found in 9 isolates as well. The results of RFLP analysis of 3 clarithromycin-resistant strains were negative for both mutations. The average MIC values for A2143G and A2142G mutants were 6 and 30 mg/L, respectively. Frequencies of A2143G and A2142G mutations were the same in all isolates tested. Strains with A2143G mutation exhibited lower MIC values than A2142G mutants. Application of PCR-RFLP method for detection of clarithromycin resistance allows for better and more efficient management of H. pylori infections.

Background. An increasing resistance ofHelicobacter pyloristrains to antimicrobial agents is the serious therapeutic problem. The aim of this study was to compare the primary and secondary resistance ofH. pyloristrains isolated between 2006–2008 (data published) and 2009–2011 to clarithromycin and levofloxacin.Material and Methods. 220 dyspeptic patients (153 before treatment, 67 after), were enrolled in the study. 51H. pyloristrains were isolated. MIC values of clarithromycin and levofloxacin were determined by theE-test method. The statistical analysis was conducted with theχ2test with Yates correction at the 0.05 significance level (P≤0.05).Results. Between 2006 and 2008, 34% (39/115) ofH. pyloristrains were resistant to clarithromycin (primary 21% (19/90), secondary 80% (20/25)). 5% (6/115) of strains were resistant to levofloxacin (primary 2% (2/90), secondary 16% ((4/25); data published) Between 2009–2011, 22% (11/51) ofH. pyloristrains were resistant to clarithromycin (primary 19% (8/43), secondary 38% (3/8)). 16% (8/51) of strains were resistant to levofloxacin (primary 12% (5/43), secondary 38% (3/8)).Conclusion. The present study has shown the increasing amount of resistantH. pyloristrains isolated from patients in Southern Poland to levofloxacin and decreasing number of resistant strains to clarithromycin.

Human pathogens belonging to the Nakaseomyces clade include Candida glabrata sensu stricto, Candida nivariensis and Candida bracarensis. Their highly similar phenotypic characteristics often lead to misidentification by conventional laboratory methods. Therefore, limited information on the true epidemiology of the Candida glabrata species complex is available. Due to life-threatening infections caused by these species, it is crucial to supplement this knowledge. The aim of the study was to estimate the prevalence of C. bracarensis and C. nivariensis in a culture collection of C. glabrata complex isolates. The study covered 353 isolates identified by biochemical methods as C. glabrata, collected from paediatric and adult patients hospitalised at four medical centres in Southern Poland. The multiplex PCR was used to identify the strains. Further species confirmation was performed via sequencing and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) analysis. One isolate was recognised as C. bracarensis (0.28%). To our knowledge, it is the first isolate in Poland. C. glabrata sensu stricto species has been confirmed for all the remaining isolates. No C. nivariensis was found. Our study has shown that the prevalence of C. nivariensis and C. bracarensis strains is infrequent. However, it should be emphasised that the incidence of these strains may differ locally and depend on environmental factors and the population.

Orthodontic microimplants have revolutionized anchorage in orthodontics but remain vulnerable to microbial colonization, potentially leading to infection and failure. Surface modifications incorporating silver nanoparticles (AgNPs) offer antimicrobial benefits, providing long-term protection against bacterial infections, while improving partial osseointegration. This study investigates hybrid coatings enriched with AgNPs, calcium (Ca), and phosphorus (P) to improve antimicrobial efficacy and reduce biofilm formation. Microimplants fabricated from the Ti6Al4V alloy were divided into six groups with varying surface treatments, including etching in hydrofluoric acid and hybrid layers containing 0.5 mol% AgNPs and CaP. Antibacterial activity was evaluated using agar diffusion and biofilm formation assays against S. aureus, E. coli, and S. mutans. Surface roughness was analyzed and correlated with biofilm formation. The model assessing the impact of biomaterials on S. aureus biofilm revealed a strong association (R² = 0.94), with biomaterial choice significantly influencing biofilm formation. The model for E. coli biofilm exhibited exceptional predictability (R² = 0.99). The model for S. mutans biofilm demonstrated an association (R² = 0.68). Hybrid coatings exhibited a promising antimicrobial activity. Biofilm formation was higher on microimplants with rougher surfaces. Hybrid coatings enriched with AgNPs and CaP enhance antimicrobial properties and partially reduce biofilm formation. It is suggested that the optimization of microimplant surface areas varies according to function. An enhanced performance can be achieved by maintaining a smooth surface for soft tissue contact, while incorporating a rough surface enriched with bactericidal and bioactive modifiers for bone contact areas.