The aim of this study was to investigate genetic diversity of Helicobacter pylori virulence markers to predict clinical outcome as well as to determine an antibiotic susceptibility of H. pylori strains in Poland. Gastric biopsies from 132 patients with gastrointestinal disorders were tested for presence of H. pylori with the use of rapid urease test, microbial culture, and polymerase chain reaction (PCR) detection. The genetic diversity of 62 H. pylori positive samples was evaluated by detection of cagA and PCR-typing of vacA and iceA virulence-associated genes. Most common H. pylori genotypes were cagA(+)vacAs1m2 (27.4%) and cagA(−)vacAs2m2 (24.2%). In logistic regression analysis, we recognized the subsequent significant associations: gastritis with ureC, i.e., H. pylori infection (p = 0.006), BMI index (p = 0.032); and negatively with iceA1 (p = 0.049) and peptic ulcer with cagA (p = 0.018). Thirty-five H. pylori strains were cultured and tested by E-test method showing that 49% of strains were resistant to at least one of the tested antibiotics. This is the first study that reports the high incidence and diversity of allelic combination of virulence genes in gastroduodenitis patients in Poland. Genotyping of H. pylori strains confirmed the involvement of cagA gene and vacAs1m1 genotype in development and severity of gastric disorder.

The emergence of drug-resistant bacterial strains continues to be one of the major challenges of medicine. For this reason, the importance of searching for novel structures of antibacterial drugs chemically different from the currently known antibiotics is still of great importance. In this study, we synthesized the thiosemicarbazide and 1,3,4-thiadiazole derivatives and tested them for antibacterial activity. In in vitro tests, we examined the activity of the synthesized substances against Gram-positive and Gram-negative bacteria strains. While all 1,3,4-thiadiazoles tested lacked significant activity, the antimicrobial response of the thiosemicarbazides was moderate and it was also dependent on the type and position of the substituent on the phenyl ring. The highest activity towards all Gram-positive bacteria strains was shown by all three linear compounds containing the trifluoromethylphenyl group in the structure. The MIC (minimum inhibitory concentration) values were in the range of 3.9–250 µg/mL. Additionally, we try to explain the mechanism of the antibacterial activity of the tested compounds using the molecular docking to DNA gyrase and topoisomerase IV, following previous reports on the molecular basis of the activity of thiosemicarbazides. Docking simulations allow the purposing dual mechanism of the antibacterial activity of the synthesized compounds through inhibition of topoisomerase IV DNA gyrase with the moderate prevalence of the topoisomerase pathway.

Six novel imidazoline derivatives were synthesized and tested in antifungal assays. One of the compounds, N-cyclohexyl-2-imino-3-(4-nitrophenyl)imidazolidine-1-carboxamide showed moderate activity against several clinical strains of Candida albicans. Its structure was solved by X-ray crystallography and its mode of action was deduced using molecular modelling. It was found to be similar to that of fluconazole. The potential for further optimization including SAR of the compound is briefly discussed.

(1) Background: Beta-lactams are the most frequently used antimicrobials, and are the first-line drugs in many infectious diseases, e.g., pneumonia, otitis media. Due to this fact, various bacteria have developed resistance to this group of drugs. (2) Methods: Eighty-seven Haemophilus parainfluenzae isolates were obtained from adults 18–70 years old in eastern Poland. The presence of 10 bla genes and 2 substitutions in ftsI reported as the most frequent in H. parainfluenzae were analyzed. (3) Results: Among 57 beta-lactam-resistant isolates, 63.2% encoded bla genes; blaTEM-1 predominated (54.4%), followed by blaOXA (19.3%), blaDHA (12.3%), blaSHV (10.5%), blaGES (7.0%), blaCMY (5.3%), blaVEB (1.8%) and blaROB-1 (1.8%). Lys-526 was the most common substitution in ftsI gene. The resistance genotypes were as follows: gBLNAS (17.5%), low-gBLNAR I (1.8%), low-gBLNAR II (1.8%), gBLNAR II (15.8%), gBLPAS (15.8%), gBLPAR (19.3%), gBLPBS I (8.8%) and gBLPBS II (1.8%); (4) Conclusions: This has been the first study to report on the high diversity of bla genes in H. parainfluenzae isolates in Poland. High sensitivity and specificity of benzylpenicillin test, as well as PCR of bla genes were shown, indicating that these methods may be useful as tools for the rapid screening of beta-lactamase prevalence and resistance to beta-lactams among H. parainfluenzae isolated from respiratory microbiota.

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