Antibacterial and antibiofilm agents in the group of xanthone derivatives with piperazine moiety active against drug-resistant Helicobacter pylori strains.

Helicobacter pylori (H. pylori) cause chronic inflammation of the gastric mucosa which can lead to epithelial atrophy and metaplasia resulting in peptic ulcer disease and gastric cancer. The increasing resistance of H. pylori to antibiotics and chemotherapeutics used to treat the infection is a serious problem. However, it has been confirmed that the introduction of effective anti-H. pylori therapy can prevent the progression to cancerous changes. This problem calls for the search for new and effective therapies. Xanthones are a group of compounds with extensive biological activities, including antibacterial activity, also against H. pylori. Addressing this issue, the aim of the study was to evaluate the potential of a group of 13 xanthone derivatives against susceptible and resistant H. pylori strains. Moreover, our objective was to conduct tests aimed at determining their ability to inhibit biofilm formation. The antimicrobial evaluation revealed that benzylpiperazine coupled at the C-2 position to xanthone (compounds C11 and C12) had good selective bacteriostatic activity against reference and clinical H. pylori strains (MBC/MIC ratio >4) but with no activity against other bacteria such as Staphylococcus aureus, Escherichia coli, and Lactobacillus paracasei. Analysis of the activity of compounds C11 and C12 against the biofilm formed by H. pylori strain ATCC 700684, and the clinical strain showed that these compounds caused a significant reduction in the amount of biofilm produced (5-20×). Moreover, cell viability analysis confirmed a 3-4× reduction in the viability of cells forming biofilm after treatment with C11 and C12. Finally,both compounds did not impair human fibroblast viability at tested concentrations and were not mutagenic in the Ames test. Therefore, they could be promising leads as antibacterial candidates for multidrug-resistant strains of H. pylori.

Voluntary counselling and testing points (VCTs) in Poland as a complementary and accessible alternative to public healthcare facilities: A comparative analysis of epidemiological data from the VCTs and the National Institute of Public Health NIH-National Research Institute (2015-2022).

OBJECTIVE: Voluntary counselling and testing points (VCTs) offer anonymous and free HIV tests in Poland. They also play an essential role in educational initiatives focused on the prevention and diagnosis of HIV and other sexually transmitted infections. However, no comprehensive data is available that summarizes the results of the work carried out by these VCTs. Therefore, our aim was to conduct a comparative analysis of epidemiological data obtained from VCTs and data reported by the epidemiological surveillance undertaken by the National Institute of Public Health NIH-National Research Institute (NIPH NIH-NRI) covering the period from 2015 to 2022. METHODS: This retrospective analysis was conducted on data from 258 071 people attending VCTs in Poland in 2015-2022. RESULTS: On average, 32 259 individuals underwent testing each year, with a notable increase in the number of people being tested in November. The average positivity rate was 1.39% (3576/258 071). The Masovian voivodeship conducted the most tests and had the highest number of positive results. The comparative analysis of the frequency of detecting positive results in VCTs and those reported in NIPH NIH-NRI data revealed that, on average, 31.49% (3576/11 356) of positive results in Poland between 2015 and 2022 were identified through tests conducted at VCTs. CONCLUSION: The positive results identified in VCTs constituted approximately one-third of all results reported by the National Institute of Public Health NIH-National Research Institute, highlighting the importance of VCTs. Moreover, the high availability of testing in the Masovian voivodeship resulted in better detection of HIV. The educational actions performed during European Testing Week increased the number of tests performed in November.

Improving Activity of New Arylurea Agents against Multidrug-Resistant and Biofilm-Producing Staphylococcus epidermidis.

Multidrug-resistant (MDR) strains of Staphylococcus epidermidis (S. epidermidis), prevalent in hospital environments, contribute to increased morbidity and mortality, especially among newborns, posing a critical concern for neonatal sepsis. In response to the pressing demand for novel antibacterial therapies, we present findings from synthetic chemistry and structure-activity relationship studies focused on arylsulfonamide/arylurea derivatives of aryloxy[1-(thien-2-yl)propyl]piperidines. Through bioisosteric replacement of the sulfonamide fragment with a urea moiety, compound 25 was identified, demonstrating potent bacteriostatic activity against clinical multidrug-resistant S. epidermidis strains (MIC50 and MIC90 = 1.6 and 3.125 µg/mL). Importantly, it showed activity against linezolid-resistant strains and exhibited selectivity over mammalian cells. Compound 25 displayed antibiofilm-forming properties against clinical S. epidermidis strains and demonstrated the capacity to eliminate existing biofilm layers. Additionally, it induced complete depolarization of the bacterial membrane in clinical S. epidermidis strains. In light of these findings, targeting bacterial cell membranes with compound 25 emerges as a promising strategy in the fight against multidrug-resistant S. epidermidis strains.

Molecular Identification of Strains within the Mycobacterium abscessus Complex and Determination of Resistance to Macrolides and Aminoglycosides.

One of the most relevant and pathogenic groups among the rapidly growing mycobacteria (RGM) is Mycobacterium abscessus complex (MABC) that includes three subspecies: M. abscessus subsp. abscessus, M. abscessus subsp. bolletii, and M. abscessus subsp. massiliense. The aim of this study was the analysis of prevalence of MABC among other non-tuberculous mycobacteria isolated from patients in the Malopolska Region of Poland, between 2018 and 2021, as well as determination of their subspecies and molecular mechanisms of resistance to macrolides and aminoglycosides. The incidence of MABC was 5,4% (12/223). Eight strains were classified as M. abscessus subsp. abscessus, three as M. abscessus subsp. massiliense and one M. abscessus subsp. bolletii. Molecular analysis showed resistance to macrolides for eight strains of M. abscessus subsp. abscessus associated with erm(41)T28 gene mutations. One strain of M. abscessus subsp. abscessus showed resistance to macrolides (two mutations simultaneously: in erm(41)T28 and rrl genes) and aminoglycosides (point mutation in rrs gene). One strain of M. abscessus subs. bolletii was resistant to macrolides (erm(41)T28 mutation), whereas presented no mutations for aminoglycosides. M. abscessus subsp. massiliense reveal no mutations. High clarithromycin resistance of M. abscessus, determines the urgent need for susceptibility-based treatment. Molecular determination of resistance mechanisms to aminoglycosides and macrolides enables fast and accurate targeted treatment implementation.

Prevalence of Closely Related Candida albicans Species among Patients with Vulvovaginal Candidiasis in Southern Poland Based on the hwp1 Gene Amplification.

Candida albicans remains the most common species isolated from women with vulvovaginal candidiasis. However, closely related species such as Candida africana and Candida dubliniensis may also occur, although they are often misidentified. The aim of the study was to confirm the phenotypic identification of C. albicans and its closely related species isolated from women with genital tract infections by amplification of the hwp1 (hyphal wall protein 1) gene in a PCR assay. We report a detailed molecular identification of C. albicans and its closely related species among 326 patients in the Malopolska region, Poland. Initial phenotypic identifications were confirmed by amplification of the hwp1 gene. Based on molecular analysis, we revealed 307 strains (94.17%) as C. albicans and 17 as C. dubliniensis (5.22%). No strain of C. africana was detected. Two patients h ad co-infection with C. albicans and C. dubliniensis (0.61%). A PCR assay targeting the hwp1 gene was reliable for correctly identifying species among the C. albicans complex.

Design and synthesis of novel arylurea derivatives of aryloxy(1-phenylpropyl) alicyclic diamines with antimicrobial activity against multidrug-resistant Gram-positive bacteria.

The alarming increase in the resistance of bacteria to the currently available antibiotics necessitates the development of new effective antimicrobial agents that are active against bacterial pathogens causing major public health problems. For this purpose, our in-house libraries were screened against a wide panel of clinically relevant Gram-positive and Gram-negative bacteria, based on which compound I was selected for further optimization. Synthetic efforts in a group of arylurea derivatives of aryloxy(1-phenylpropyl) alicyclic diamines, followed with an in vitro evaluation of the activity against multidrug-resistant strains identified compound 44 (1-(3-chlorophenyl)-3-(1-{3-phenyl-3-[3-(trifluoromethyl)phenoxy] propyl}piperidin-4-yl)urea). Compound 44 showed antibacterial activity against Gram-positive bacteria including fatal drug-resistant strains i.e., Staphylococcus aureus (methicillin-resistant, MRSA; vancomycin-intermediate, VISA) and Enterococcus faecium (vancomycin-resistant, VREfm) at low concentrations (0.78-3.125 µg/mL) comparable to last resort antibiotics (i.e., vancomycin and linezolid). It is also potent against biofilm-forming S. aureus and Staphylococcus epidermidis (including linezolid-resistant, LRSE) strains, but with no activity against Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). Compound 44 showed strong bactericidal properties against susceptible and drug-resistant Gram-positive bacteria. Depolarization of the bacterial cytoplasmic membrane induced by compound 44 suggests a dissipation of the bacterial membrane potential as its mechanism of antibacterial action. The high antimicrobial activity of compound 44, along with its selectivity over mammalian cells (lung MCR-5 and skin BJ fibroblast cell lines) and no hemolytic properties toward horse erythrocytes, proposes arylurea derivatives of aryloxy(1-phenylpropyl) alicyclic diamines for development of novel antibacterial agents.

Antimicrobial susceptibility and prevalence of extended-spectrum beta-lactamases in clinical strains of Klebsiella pneumoniae isolated from pediatric and adult patients of two Polish hospitals.

Klebsiella pneumoniae due to the presence of multiple antibiotic resistance mechanisms is one of the most threatening human pathogens nowadays. The aim of the study was to characterize antimicrobial susceptibility, presence of resistance mechanisms and the prevalence of selected genes encoding ESBLs in 170 K. pneumoniae isolates recovered from children and adults hospitalized in two Polish medical centers from 2008 to 2015. The phenotypic identification of strains was confirmed by amplification of mdh gene. ESBLs, metallo-beta- lactamases, Klebsiella pneumoniae carbapenemases and OXA-48 were detected using phenotypic tests. The blaCTX-M-1, blaTEM and blaSHV ESBL genes were amplified by PCR. Pediatric K. pneumoniae isolates displayed significantly higher resistance to piperacillin/tazobactam, cefoxitin, imipenem, amikacin and ciprofloxacin than strains obtained from adults (P<0.05). The presence of ESBLs, OXA-48, KPC and MBL was confirmed in 80.6%, 21.8%, 8.2% and 2.4%, respectively, of the tested strains. The CTX-M-1 enzymes were predominant (91.2%), followed by TEM (63.5%) and SHV (11.8%). The blaTEM was significantly more common in adults than in children (P<0.05). Dual or triple bla genes were observed in 55.9% and 8.2% of K. pneumoniae isolates. Further local epidemiological studies are required to monitor the dissemination of multidrug-resistant K. pneumoniae strains.

Prevalence of human pathogens of the clade Nakaseomyces in a culture collection-the first report on Candida bracarensis in Poland.

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.

Nested PCR for the detection of Aspergillus species in maxillary sinus samples of patients with chronic sinusitis.

BACKGROUND: Fungal rhinosinusitis has become an increasingly recognized disease, being Aspergillus species responsible for most of the cases. Its diagnosis is quite difficult because of the non-specific symptoms and low sensitivity of the current diagnostic methods. AIMS: An Aspergillus-specific nested polymerase chain reaction (PCR) assay using biopsy specimens taken from the maxillary sinuses was performed in order to assess its usefulness. Conventional diagnostic methods (histology and culture) were also carried out. METHODS: A case-control study was performed in the Institute of Stomatology, Jagiellonian University in Kraków, between 2011 and 2014. The case group consisted of 21 patients with suspected rhinosinusal mycetoma while the control group included 46 patients with no suspicion of fungal rhinosinusitis. The two-step PCR assay amplified an Aspergillus specific portion of the 18S rRNA gene. Interval estimation of sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were calculated to assess the diagnostic test performance. The agreement between the PCR and the other tests was evaluated using the Kappa coefficient (k). RESULTS: Ninety percent of the samples obtained from patients diagnosed with mycetoma yielded positive PCR results. The PCR showed almost perfect concordance with histology (k=0.88). Sensitivity, specificity, PPV and NPV estimates were 90%; 95% CI: (55.5-99.7%), 98.3%; 95% CI: (90.9-100%), 90%; 95% CI: (55.5-99.7%) and 98.3%; 95% CI: (90.9-100%), respectively. One clinical sample showed growth of Aspergillus fumigatus and positive PCR despite the negative histological examination. CONCLUSIONS: Nested PCR assay is a promising diagnostic tool to evaluate the presence of Aspergillus in the tissue of maxillary sinus from patients with suspicion of sinus aspergillosis.

Preliminary antifungal activity assay of selected chlorine-containing derivatives of xanthone and phenoxyethyl amines.

The aim of this study was to evaluate antifungal activity in a diverse group of chlorine-containing xanthone and phenoxyethyl amine derivatives - and to select the most promising compounds for further studies. The antifungal efficacy of 16 compounds was tested with qualitative and quantitative methods against both reference and clinical strains of dermatophytes, moulds and yeasts. The disc-diffusion method has demonstrated that from 16 tested compounds, 7 possess good antifungal activity against dermatophytes and/or moulds while none of them has shown good efficacy against yeasts or bacterial strains. The most active compounds (2, 4, 10, 11, 12, 15, 16) were tested quantitatively by broth dilution method to obtain MIC values. The MIC values against dermatophytes ranged from 8 to 64 µg/ml. Compound 2 was the most active one against dermatophytes (MIC 50 and MIC 90 were 8 µg/ml). The MIC values for moulds ranged from 16 to 256 µg/ml. Compound 4 was the most active one against moulds, with MIC 50 and MIC 90 values amounting to 32 µg/ml. Among the tested compounds, compound 4 (derivative of xanthone) was the most active one and expressed good antifungal efficacy against clinical strains of dermatophytes and moulds. However, another xanthone derivative (compound 2) was the most active and selective against dermatophytes.

Anti-Helicobacter pylori activities of selected N-substituted cinnamamide derivatives evaluated on reference and clinical bacterial strains.

In this study, thirty-five N-substituted derivatives of cinnamic acid amide (cinnamamide) were evaluated for anti-Helicobacter pylori activity using an agar disc-diffusion method. Qualitative screening was performed on a reference H. pylori strain (ATCC 43504), resulting in the identification of the three most active compounds, 8 (R,S-(2E)-3-(4-chlorophenyl)-N-(2-hydroxypropyl)prop-2-enamide, minimal inhibitory concentration, MIC = 7.5 µg/mL), 23 ((2E)-3-(4-chlorophenyl)-N-(2-hydroxycyclohexyl)prop-2-enamide, MIC = 10 µg/mL), and 28 ((2E)-3-(4-chlorophenyl)-N-(4-oxocyclohexyl)prop-2-enamide, MIC = 10 µg/mL). These compounds were further tested on twelve well-characterized clinical strains, yielding MIC values that ranged from 10 to 1000 µg/mL. Preliminary safety assessments of the compounds were made using the MTT viability test for cytotoxicity and Ames test for mutagenicity, which showed them to be generally safe, although compounds 8 and 28 showed mutagenic activity at some of the tested concentrations. The results of this study showed the anti-H. pylori potential of cinnamamide derivatives.

Anti-Helicobacter pylori activity of some newly synthesized derivatives of xanthone.

A series of 20 xanthone derivatives was synthesized and evaluated for anti-Helicobacter pylori (H. pylori) activity. Qualitative and quantitative in vitro tests using the Kirby-Bauer method (agar disc-diffusion method) were performed. The tested compounds were screened against clarithromycin- and/or metronidazole-resistant strains of H. pylori. As a reference, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial strains were examined. On the basis of microbiological assays, xanthones can be considered as potential anti-H. pylori agents. They displayed significant activity against the examined strains, which was higher against the bacteria resistant to metronidazole than clarithromycin. The lowest MIC values ranging up to 20 mg l-1 were observed for the following compounds: 3, 4, 8, 9, 12, 19 (against the metronidazole-resistant strains) and the compound 10 (against the clarithromycin-resistant strain). These preliminary results for screening of xanthone derivatives form a part of an ongoing study of the structure-activity relationships of a large group of compounds. Microbiological assays will be conducted afterwards to determine the mechanism of xanthones' action against H. pylori.

Levofloxacin resistance of Helicobacter pylori strains isolated from patients in southern Poland, between 2006-2012.

An increasing resistance of Helicobacter pylori (H. pylori) to antimicrobial agents leads to the need of regional monitoring of the prevalence resistant strains (according to the Maastricht/Florence consensus report, 2012). The aim of the study was to assess the resistance to levofloxacin of H. pylori strains isolated from adult patients of Malopolska region in Poland. Bioptates taken from gastric mucosa during gastroscopy constituted the material for the study. Two hundred ten H. pylori strains were isolated from 811 patients. A majority of strains (171) came from patients before the treatment of H. pylori infections while the remaining 39 strains were isolated from patients after the failed therapy. Susceptibility of H. pylori to levofloxacin was determined by strips impregnated with antibiotic gradient (E-test, bioMerieux). The obtained minimum inhibitory concentration (MIC) values ranged from 0.002 mg/L to 32 mg/L. The percentage of strains resistant to levofloxacin amounted to 8.10% (17/210). Among the group of strains isolated from patients before the treatment, 5.85% (10/171) of H. pylori strains were resistant to levofloxacin. In the group of strains isolated from patients after the treatment 17.95% (7/39) of strains were resistant. The difference in the frequency of H. pylori strains resistant to levofloxacin in patients before and after the treatment of the infection due to H. pylori was statistically significant (p = 0.0297). The low percentage of H. pylori strains resistant to levofloxacin justify that the introduction of a triple therapy with levofloxacin is a good alternative in the treatment of H. pylori infections, especially in regions with high prevalence of H. pylori strains resistant to clarithromycin (> 20%).

PCR-RFLP detection of point mutations A2143G and A2142G in 23S rRNA gene conferring resistance to clarithromycin in Helicobacter pylori strains.

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Variability in Prevalence of Helicobacter pylori Strains Resistant to Clarithromycin and Levofloxacin in Southern Poland.

Background. An increasing resistance of Helicobacter pylori strains to antimicrobial agents is the serious therapeutic problem. The aim of this study was to compare the primary and secondary resistance of H. pylori strains 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. 51 H. pylori strains were isolated. MIC values of clarithromycin and levofloxacin were determined by the E-test method. The statistical analysis was conducted with the χ(2) test with Yates correction at the 0.05 significance level (P ≤ 0.05). Results. Between 2006 and 2008, 34% (39/115) of H. pylori strains 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) of H. pylori strains 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 resistant H. pylori strains isolated from patients in Southern Poland to levofloxacin and decreasing number of resistant strains to clarithromycin.