Browsing by Author "Bandere, Dace"
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Item Adherence Level to Arterial Hypertension Treatment: A Cross-Sectional Patient Survey and Retrospective Analysis of the NHS Prescription Database(2021-08-23) Gavrilova, Anna; Bandere, Dace; Logviss, Konstantīns; Šmits, Dins; Urtāne, Inga; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Department of Applied Pharmacy; Department of Public Health and EpidemiologyOne of the major problems in cardiology practice is poor adherence to antihypertensive medication. This study aimed to evaluate medication adherence; we also aim to investigate the predictors of intentional and unintentional non-adherence. We issued a survey containing questions about patient demographics, blood pressure control, pharmaceutical care, and adherence level to medication. Retrospective analysis of the prescription database of the National Health Service of the Republic of Latvia was performed. The prevalence of non-adherence was 45.9%. The lowest adherence rate (38.2%) was found among patients taking medication for 2–4.9 years. Even though 84.7% of respondents had a blood pressure monitor at home, only 25.3% of them reported measuring blood pressure regularly. There were differences between the groups of adherent patients in terms of the patients’ net income (p = 0.004), medication co-payments (p = 0.007), and whether the pharmacist offered to reduce the costs of drug therapy (p = 0.002). Roughly half of the prescriptions (50.4%) containing perindopril were purchased by patients from pharmacies. The medication adherence level and blood pressure control at home were assessed as low. Intentionally non-adherent respondents discontinued their medication because of fear of getting used to medicines. The pharmacists’ behaviour in terms of offering to reduce the costs of medications used was influenced by socio-economic factors.Item Advantages of analysing both pairwise SNV-distance and differing SNVs between Mycobacterium tuberculosis isolates for recurrent tuberculosis cause determination.(2023-03-01) Sadovska, Darja; Nodieva, Anda; Pole, Ilva; Ķimsis, Jānis; Vīksna, Anda; Ozere, Iveta; Norvaiša, Inga; Bandere, Dace; Ranka, Renāte; Department of Infectology; Department of Pharmaceutical ChemistryEndogenous reactivation and exogenous reinfection are two possible causes of recurrent tuberculosis (TB). However, in some cases, precise cause determination can be challenging. In this study, we used whole genome sequencing to determine pairwise SNV distances and detect differing SNVs in initial and subsequent isolates for recurrent TB cases when the first and second episodes were caused by Mycobacterium tuberculosis ( Mtb) strains with an identical spoligotype pattern. In total, 104 Mtb isolates from 36 recurrent TB and 16 single TB episode patients were included in the study. Most isolate pairs belonged to the SIT1 (n=21), SIT42 (n=9), SIT53 (n=9), and SIT254 (n=7) spoligotypes, and in 27 cases, resistance to at least one anti-TB drug was found in either isolate. Drug susceptibility was more common in the recurrent TB patient cohort, and longitudinal single TB episode isolates were more prone to be drug-resistant (p=0.03), while the association between patient cohort and spoligotype was not statistically significant (p=0.07). The pairwise SNV-distance between the longitudinal single TB episode isolates was small (0-7 SNVs). Among the recurrent TB isolates, based on the high SNV-distance (38-273 SNVs), six reinfection cases (16.7%) were identified. This distance was small (<10 SNVs) in the remaining 30 isolate pairs. Further analysis of differing SNVs revealed that 22 (61.1%) cases could be classified as possible reactivation. Notably, despite the small distance of 2-7 SNVs, initial isolates of eight patients (22.2%) had several SNVs that were not found in the second isolates; therefore, these cases were classified as reinfection with a closely related Mtb strain. No statistically significant difference in the time interval between specimen collection in the reactivation and reinfection Mtb sample groups (p=0.13) or an association between recurrence cause and drug resistance status (p=0.62) or spoligotype (p=0.79) could be detected. The mycobacterial median mutation rate of longitudinal single TB episodes and possible reactivation isolate pairs (n=37) was 0.12 SNVs/genome/year (IQR 0-0.39), and in 18 cases (48.6%), it was equal to zero. No statistically significant differences in mutation rate were found between recurrent TB and longitudinal single TB episode isolates (p=0.087), drug-susceptible and resistant isolates (p=0.37) or isolates of Beijing and other genotype families (p=0.33). Furthermore, four cases of fluoroquinolone resistance development through the acquired SNVs in the gyrA gene were identified. To conclude, this study highlighted the complexity of recurrent episode cause determination and showed the usefulness of differing SNV identification in both Mtb isolates in such cases. Expected drug susceptibility was the only discriminative factor for recurrent TB episode-causing mycobacterial strains, while no differences between reactivation and reinfection sample groups could be identified.Item Anthelmintic Activity of Tanacetum vulgare L. (Leaf and Flower) Extracts against Trichostrongylidae Nematodes in Sheep In Vitro(2023-07) Kļaviņa, Alīna; Keidāne, Dace; Ganola, Kristīne; Lūsis, Ivars; Šukele, Renāte; Bandere, Dace; Kovalcuka, Liga; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš UniversityDue to the high prevalence of gastrointestinal nematodes in sheep, the growing anthelmintic resistance, and the development of organic farming systems, sustainable alternatives are being sought. One such method is phytotherapy. This study aimed to evaluate the in vitro ovicidal and larvicidal activity of extracts of tansy ( Tanacetum vulgare L.) growing in Latvia on gastrointestinal nematodes (Trichostrongylidae) in sheep. The leaves and flowers of the tansy were extracted separately in 70%, 50%, and 30% ethanol and acetone. Six concentrations were prepared from each extract 500 mg/mL, 200 mg/mL, 100 mg/mL, 50 mg/mL, 20 mg/mL, and 10 mg/mL. In vitro egg hatching test and micro-agar larval development test were performed. Extracts of tansy have strong larvicidal activity. The highest percentage of larvae inhibition for most of the extracts was 100%, but for egg inhibition, it was 95.8% for the 200 mg/mL concentration of 50% acetone and 93.3% for the 500 mg/mL concentration of 50% ethanol leaf extracts. All tansy extracts had ovicidal and larvicidal activity against Trichostrongylidae in sheep.Item Antibacterial activity against bovine mastitis-inducing pathogens and antiradical activity of polyphenolic-compounds-containing plant extracts. Doctoral Thesis(Rīga Stradiņš University, 2025) Teterovska (Šukele), Renāte; Bandere, Dace; Koka, RudīteBovine mastitis is an infectious disease of the cow’s udder, which is usually treated with antibiotics. The overuse and misuse of antibiotics has led to the widespread development of bacterial resistance. Restrictions on the use of antibiotics create a need for alternative treatments and prophylactic measures to reduce the incidence and spread of mastitis. Antioxidant properties of plants – ability to scavenge free radicals, help animals recover and heal faster. Herbal medicine has been used traditionally by farmers for centuries to treat infectious and chronic diseases. However, there is little scientific evidence on the veterinary use of plant extracts. The Thesis aims to provide information on the use of plant extracts against bovine mastitis pathogens, their antiradical activity and to characterise their polyphenolic content. The dried plant material was extracted with 30 %, 50 %, 70 % ethanol and acetone and then freeze-dried for further analysis. The total phenolic, flavonoid, and tannin contents were determined by spectroscopic methods. Fourier transform infrared spectroscopy and high-performance liquid chromatography were used to characterise the chemical composition of the extracts. Clinical isolates inducing bovine mastitis (Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus) and reference cultures of S. aureus and E. coli were used for antibacterial tests. All extracts were screened for their antibacterial activity using a disc diffusion test, and the minimum inhibitory concentration and the minimum bactericidal concentration were determined for the most effective extracts. The antiradical activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The type of solvent affected the amount of phenolics extracted and the pharmacological effects of the extracts. The plants contained comparable amounts of tannins, which are not often reported in studies but have pharmacological activities. The acetone extracts had a higher total phenolic content and a higher total flavonoid content. All the plant extracts analysed were effective against S. aureus, but the effect against other bovine mastitis pathogens varied by the type of extract used. The types of phenolic compounds present in these plant extracts have a significant impact on the antioxidant activity. The bark of Q. robur and the herbs of C. vulgaris, and the flower and leaf of T. vulgare had good antioxidant and antibacterial potential. Plant extracts have promising pharmacological effects in vitro for the development of a product for bovine mastitis.Item Antibacterial activity against bovine mastitis-inducing pathogens and antiradical activity of polyphenolic-compounds-containing plant extracts. Summary of the Doctoral Thesis(Rīga Stradiņš University, 2025) Teterovska (Šukele), Renāte; Bandere, Dace; Koka, RudīteBovine mastitis is an infectious disease of the cow’s udder, which is usually treated with antibiotics. The overuse and misuse of antibiotics has led to the widespread development of bacterial resistance. Restrictions on the use of antibiotics create a need for alternative treatments and prophylactic measures to reduce the incidence and spread of mastitis. Antioxidant properties of plants – ability to scavenge free radicals, help animals recover and heal faster. Herbal medicine has been used traditionally by farmers for centuries to treat infectious and chronic diseases. However, there is little scientific evidence on the veterinary use of plant extracts. The Thesis aims to provide information on the use of plant extracts against bovine mastitis pathogens, their antiradical activity and to characterise their polyphenolic content. The dried plant material was extracted with 30 %, 50 %, 70 % ethanol and acetone and then freeze-dried for further analysis. The total phenolic, flavonoid, and tannin contents were determined by spectroscopic methods. Fourier transform infrared spectroscopy and high-performance liquid chromatography were used to characterise the chemical composition of the extracts. Clinical isolates inducing bovine mastitis (Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus) and reference cultures of S. aureus and E. coli were used for antibacterial tests. All extracts were screened for their antibacterial activity using a disc diffusion test, and the minimum inhibitory concentration and the minimum bactericidal concentration were determined for the most effective extracts. The antiradical activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The type of solvent affected the amount of phenolics extracted and the pharmacological effects of the extracts. The plants contained comparable amounts of tannins, which are not often reported in studies but have pharmacological activities. The acetone extracts had a higher total phenolic content and a higher total flavonoid content. All the plant extracts analysed were effective against S. aureus, but the effect against other bovine mastitis pathogens varied by the type of extract used. The types of phenolic compounds present in these plant extracts have a significant impact on the antioxidant activity. The bark of Q. robur and the herbs of C. vulgaris, and the flower and leaf of T. vulgare had good antioxidant and antibacterial potential. Plant extracts have promising pharmacological effects in vitro for the development of a product for bovine mastitis.Item Antibacterial Activity of Tanacetum vulgare L. Extracts against Clinical Isolates of Bovine Mastitis(2023-03) Šukele, Renāte; Bārzdiņa, Ance; Koka, Rudīte; Skadins, Ingus; Lauberte, Līga; Brangule, Agnese; Kovalcuka, Liga; Bandere, Dace; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Department of Biology and Microbiology; Laboratory of Finished Dosage FormsA bovine mastitis is an infectious disease, which is usually treated with antibiotics. Alternatively, herbal medicine has been proposed due to bacterial resistance. The aim of this study was to determine the antibacterial activity of the acetonic and ethanolic extracts of dried flowers and leaves of Tanacetum vulgare L. against bovine mastitis-inducing clinical isolates such as Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus, and reference cultures of S. aureus and E. coli. The extracts of T. vulgare showed partial antibacterial activity against tested strains of S. aureus. The MIC and MBC values of a 70% ethanol extract of flowers (MIC = 3.4 mg/mL, MBC = 3.4–6.8 mg/mL) were lower than for the 70% ethanol extract of leaves (MIC = 15.7–31.4 mg/mL, MBC = 62.9–125.9 mg/mL). The flower extracts showed low activity against E. coli (MIC = 53.9 mg/mL, MBC = 53.9–107.8 mg/mL) and S. agalactiae (MIC, MBC = 53.9 mg/mL). T. vulgare leaf extracts had minimal antibacterial effects against Streptococcus strains (MIC = 31.4–62.9 mg/mL, MBC = 53.9–125.9 mg/mL) and Serratia liquefaciens (MIC, MBC = 125.9 mg/mL). However, flower extracts had a higher phenolic content that did not correlate with antibacterial effects. T. vulgare flower and leaf extracts could be combined to obtain broader antibacterial effects.Item Antibacterial effects of oak bark (Quercus robur) and heather herb (Calluna vulgaris L.) extracts against the causative bacteria of bovine mastitis(2022-09) Šukele, Renāte; Skadiņš, Ingus; Koka, Rudīte; Bandere, Dace; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Department of Biology and MicrobiologyBackground and Aim: Bovine mastitis has a negative impact on animals, and improper antibiotic use has caused an increase in bacterial resistance. Therefore, medicinal plants could serve as an alternative treatment for this condition. Polyphenols have potential as antibiotic agents. Oak bark has long been used as a medicine and has shown antibacterial effects. Moreover, research on heather plant demonstrated that it has antibacterial properties. This study aimed to assess the antibacterial effects of oak (Quercus robur) bark and heather (Calluna vulgaris L.) herb extracts against common bovine mastitis pathogens. Materials and Methods: Dried oak bark and heather herb were used to prepare extracts using 30%, 50%, and 70% ethanol and acetone as solvents. Their polyphenol content was determined using the Folin-Ciocalteu method. Bovine mastitis-inducing clinical isolates of Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus, and reference cultures of S. aureus and E. coli were used for antibacterial tests. All extracts were screened through a disk diffusion test to ascertain their antibacterial effects, and the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined for the most effective extracts. Results: Oak bark extracts had variable antibacterial effects against S. aureus and Streptococcus strains, but no statistically significant difference was observed in activity against E. coli. The disk diffusion test showed that the oak bark extracts obtained using acetone and ethanol at 30% yielded the best results. However, the 70% acetone oak extract alone affected all types of bacteria. Further antibacterial tests of 70% acetone and 30% ethanol oak extracts revealed that the lowest MIC and MBC scores were against S. aureus strains and E. coli reference cultures. Conversely, the heather herb extracts exhibited broader activity against all types of bacteria, although better results were observed against Gram-positive bacteria. There was also a negative correlation between solvent concentration and antibacterial effect (p < 0.05, r = −0.507). The highest inhibition zone scores and broadest spectrum were observed in samples prepared in 30% ethanol. There was no statistically significant correlation between the phenolic content of plants and their antibacterial effects. Conclusion: Oak bark and heather extracts could be used as potential antibacterial agents against bovine mastitis pathogens.Item Antidiabetic Properties of the Root Extracts of Dandelion (Taraxacum officinale) and Burdock (Arctium lappa)(2024-04-03) Zolotova, Daria; Teterovska, Renāte; Bandere, Dace; Lauberte, Līga; Niedra, Santa; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Laboratory of Finished Dosage FormsSeveral preclinical studies suggest the potential of edible plants in controlling blood sugar levels and stabilizing diet. The goals of the study were to examine, analyze, and describe whether there are chemical compounds in dandelion and burdock roots that could have antidiabetic properties. The 70% ethyl alcohol and lyophilizate extracts (AE and LE, respectively), were used, and analyses were carried out on their total polysaccharide (TP), total phenolic content (TPC), tannin, and inulin. The antioxidant activity of extracts was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, and hypoglycemic properties were based on α-amylase activity. Liquid chromatography–mass spectrometry was used for the tentative identification of the chemical components. Qualitative techniques confirmed the presence of inulin in both roots. Analysis of TPC, tannin content, DPPH assay, and α-amylase activity revealed higher values for burdock compared to dandelion. However, dandelion exhibited higher TP content. Burdock contained a small amount of tannin, whereas the tannin content in dandelion was insignificant. All LE consistently exhibited higher values in all analyses and assays for all roots compared to AE. Despite burdock root showing overall better results, it is uncertain whether these plants can be recommended as antidiabetic agents without in vivo studies.Item Antimicrobial and Antibiofilm Properties of Latvian Honey against Causative Agents of Wound Infections(2023-04-26) Skadiņš, Ingus; Labsvārds, Krišs Dāvids; Grava, Andra; Amirian, Jhaleh; Tomsone, Laura Elīna; Ruško, Jānis; Viksna, Arturs; Bandere, Dace; Brangule, Agnese; Department of Biology and Microbiology; Department of Pharmaceutical ChemistryHoney is widely used in traditional medicine and modern wound healing biomaterial research as a broad-spectrum antimicrobial, anti-inflammatory and antioxidant agent. The study’s objectives were to evaluate the antibacterial activity and polyphenolic profiles of 40 monofloral honey samples collected from beekeepers in the territory of Latvia. The antimicrobial and antifungal activity of Latvian honey samples were compared with commercial Manuka honey and the honey analogue sugar solutions–carbohydrate mixture and tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, clinical isolates Extended-Spectrum Beta-Lactamases produced Escherichia coli, Methicillin-resistant Staphylococcus aureus and Candida albicans. Antimicrobial activity was evaluated with the well-diffusion method (80% honey solution w/v) and microdilution method. The honey samples with the highest antimicrobial potential were tested to prevent biofilm development and activity against a preformed biofilm. The principal component analysis of the antimicrobial properties of honey samples vs. polyphenolic profile was performed. Eleven honey samples exhibited antibacterial activity to all investigated bacteria. The antibacterial effect of the samples was most significant on the Gram-positive bacteria compared to the studied Gram-negative bacteria. Latvian honey presents promising potential for use in wound healing biomaterials, opening the possibility of achieving long-term antibacterial effects.Item The Antioxidant Activity of Wild-Growing Plants Containing Phenolic Compounds in Latvia(2023-12) Teterovska, Renāte; Sīle, Inga; Paulausks, Artūrs; Kovalcuka, Liga; Koka, Rudīte; Mauriņa, Baiba; Bandere, Dace; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Department of Applied Pharmacy; Laboratory of Finished Dosage Forms; Department of Biology and MicrobiologyEthnobotanical reports from Latvia show that Tanacetum vulgare, Calluna vulgaris, Quercus robur, Artemisa absinthium, and Artemisia vulgaris contain phenolic compounds that have antioxidant properties, which can be beneficial in the treatment and prophylaxis of many diseases. The aim of this study was to characterize the phenolic compounds and antioxidant properties of these plants. Plant extracts were prepared using ethanol or acetone and then freeze-dried. Their total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC) were determined and characterized by HPLC. Their antioxidant properties were determined using a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. C. vulgaris herb and T. vulgare leaf extracts contained the highest amounts of flavonoids, but the bark of Q. robur had mostly tannins and phenolic acids. A. absinthium and A. vulgaris had the lowest amounts of polyphenols. When compared using extraction solvents, all acetone extracts had more TPC, more TFC, and better antioxidant activity. All plants contained chlorogenic acid, which contributes to antioxidant properties. The analysed plant extracts could be used in future studies to develop medicinal products with antioxidant properties.Item Application of Mycobacterium tuberculosis whole-genome sequencing to address epidemiologically and clinically relevant issues and improve tuberculosis control strategies. Doctoral Thesis(Rīga Stradiņš University, 2025) Sadovska, Darja; Ranka, Renāte; Bandere, DaceDespite significant advancements in tuberculosis (TB) diagnostics, treatment, and prevention, the disease remains a major global public health challenge, with only limited reductions in incidence rates observed. In recent years, whole-genome sequencing (WGS) of Mycobacterium tuberculosis isolates has become a key approach for studying various aspects of TB, providing high-resolution insights into strain phylogenetic diversity, drug resistance mechanisms, disease transmission dynamics, and recurrence causes. Although WGS offers a promising alternative to widely implemented molecular and culture-based M. tuberculosis analysis methods, further improvements in sequencing data analysis strategies are needed to fully unlock its potential for addressing critical scientific, epidemiological, and clinical challenges in TB control. This doctoral thesis aimed to apply WGS to M. tuberculosis isolates from Latvian patients to address unresolved epidemiologically and clinically relevant issues impacting TB control and propose improvements for current WGS data analysis strategies. This research focused on two key subsets of patients with TB: those who experienced recurrent TB episodes and those suspected of being part of the same TB clusters based on epidemiological data and conventional genotyping results. The studied population included adults and children with pulmonary or extrapulmonary TB. M. tuberculosis isolates were subjected to WGS for genetic-variant-based strain genotyping, phylogenetic analyses, determination of the causes of recurrent TB episodes, identification of epidemiologically relevant TB clusters, delineation of transmission chains, detection of mixed-strain infections, and WGS-based drug susceptibility testing (DST). Relevant clinical and epidemiological data and results from previous M. tuberculosis isolate analyses were retrieved from patients’ medical records. Conventional genotyping (spoligotyping and insertion sequence 6110 restriction fragment length polymorphism analysis) and phenotypic DST results were compared with WGS findings. Patients’ diagnoses, sputum smear microscopy results, specimen collection timelines, contact tracing and geospatial data were integrated to interpret the WGS results according to the analysis objective. WGS-assigned lineages and sub-lineages generally agreed with the spoligotyping results of the M. tuberculosis isolates studied, with both methods revealing significant variability in M. tuberculosis genotypes in Latvia, even within specific TB patient subsets. The isolates within the two most prevalent M. tuberculosis genotype families in Latvia, Beijing and LAM, exhibited greater genetic relatedness than isolates from other genotype families, with varying drug resistance distribution frequencies observed among different M. tuberculosis spoligotypes. Distinguishing between the two possible causes of TB recurrence (endogenous reactivation and exogenous reinfection) was more precise when performed as a part of the TB cluster transmission chain delineation. This approach integrated WGS data with relevant clinical and epidemiological information, as identifying pairwise single nucleotide variant (SNV) distances and analysing differing SNVs between isolates proved insufficient. Using genetic distance thresholds of 12 SNVs for identifying epidemiologically relevant TB clusters and 5 SNVs for inferring recent transmission events proved effective in a low-to-moderate TB incidence setting. However, the close genetic relatedness of isolates belonging to Beijing and LAM genotype families, which are highly prevalent in Latvia, should be considered during TB cluster identification to avoid the risk of false clustering. Limitations in TB transmission chain delineation included unidentified active TB cases, variability in M. tuberculosis mutation rate, low genetic variability of the pathogen, and tight specimen collection timeline of genetically identical isolates. The proposed integrated approach significantly complemented epidemiological investigation and conventional genotyping results, enabling more accurate identification of source cases and evaluation of index cases. However, its application may not be necessary for all epidemiologically relevant cases. Lastly, discordances between phenotypic and WGS-based DST among the studied isolates were attributed to the technical complexities of phenotypic tests, the variable effects of genetic variants on the minimal inhibitory concentration of drugs, and insufficient data on drug-resistance-conferring variants. While WGS-based DST cannot fully replace pDST, combining these methods provides the most accurate assessment of drug resistance patterns. To conclude, this research provided valuable insights into the TB transmission dynamics in Latvia, the genetic diversity of M. tuberculosis genotypes circulating in the country, and the distribution of drug-resistance-conferring variants among these genotypes. It also highlighted challenges in phenotypic and WGS-based DST, evaluated different WGS-based strategies for determining the causes of recurrent TB, and proposed an integrative approach for delineating TB transmission chains. These findings support the potential of integrating WGS into routine practice as part of a comprehensive local TB surveillance program.Item Application of Mycobacterium tuberculosis whole-genome sequencing to address epidemiologically and clinically relevant issues and improve tuberculosis control strategies. Summary of the Doctoral Thesis(Rīga Stradiņš University, 2025) Sadovska, Darja; Ranka, Renāte; Bandere, DaceDespite significant advancements in tuberculosis (TB) diagnostics, treatment, and prevention, the disease remains a major global public health challenge, with only limited reductions in incidence rates observed. In recent years, whole-genome sequencing (WGS) of Mycobacterium tuberculosis isolates has become a key approach for studying various aspects of TB, providing high-resolution insights into strain phylogenetic diversity, drug resistance mechanisms, disease transmission dynamics, and recurrence causes. Although WGS offers a promising alternative to widely implemented molecular and culture-based M. tuberculosis analysis methods, further improvements in sequencing data analysis strategies are needed to fully unlock its potential for addressing critical scientific, epidemiological, and clinical challenges in TB control. This doctoral thesis aimed to apply WGS to M. tuberculosis isolates from Latvian patients to address unresolved epidemiologically and clinically relevant issues impacting TB control and propose improvements for current WGS data analysis strategies. This research focused on two key subsets of patients with TB: those who experienced recurrent TB episodes and those suspected of being part of the same TB clusters based on epidemiological data and conventional genotyping results. The studied population included adults and children with pulmonary or extrapulmonary TB. M. tuberculosis isolates were subjected to WGS for genetic-variant-based strain genotyping, phylogenetic analyses, determination of the causes of recurrent TB episodes, identification of epidemiologically relevant TB clusters, delineation of transmission chains, detection of mixed-strain infections, and WGS-based drug susceptibility testing (DST). Relevant clinical and epidemiological data and results from previous M. tuberculosis isolate analyses were retrieved from patients’ medical records. Conventional genotyping (spoligotyping and insertion sequence 6110 restriction fragment length polymorphism analysis) and phenotypic DST results were compared with WGS findings. Patients’ diagnoses, sputum smear microscopy results, specimen collection timelines, contact tracing and geospatial data were integrated to interpret the WGS results according to the analysis objective. WGS-assigned lineages and sub-lineages generally agreed with the spoligotyping results of the M. tuberculosis isolates studied, with both methods revealing significant variability in M. tuberculosis genotypes in Latvia, even within specific TB patient subsets. The isolates within the two most prevalent M. tuberculosis genotype families in Latvia, Beijing and LAM, exhibited greater genetic relatedness than isolates from other genotype families, with varying drug resistance distribution frequencies observed among different M. tuberculosis spoligotypes. Distinguishing between the two possible causes of TB recurrence (endogenous reactivation and exogenous reinfection) was more precise when performed as a part of the TB cluster transmission chain delineation. This approach integrated WGS data with relevant clinical and epidemiological information, as identifying pairwise single nucleotide variant (SNV) distances and analysing differing SNVs between isolates proved insufficient. Using genetic distance thresholds of 12 SNVs for identifying epidemiologically relevant TB clusters and 5 SNVs for inferring recent transmission events proved effective in a low-to-moderate TB incidence setting. However, the close genetic relatedness of isolates belonging to Beijing and LAM genotype families, which are highly prevalent in Latvia, should be considered during TB cluster identification to avoid the risk of false clustering. Limitations in TB transmission chain delineation included unidentified active TB cases, variability in M. tuberculosis mutation rate, low genetic variability of the pathogen, and tight specimen collection timeline of genetically identical isolates. The proposed integrated approach significantly complemented epidemiological investigation and conventional genotyping results, enabling more accurate identification of source cases and evaluation of index cases. However, its application may not be necessary for all epidemiologically relevant cases. Lastly, discordances between phenotypic and WGS-based DST among the studied isolates were attributed to the technical complexities of phenotypic tests, the variable effects of genetic variants on the minimal inhibitory concentration of drugs, and insufficient data on drug-resistance-conferring variants. While WGS-based DST cannot fully replace pDST, combining these methods provides the most accurate assessment of drug resistance patterns. To conclude, this research provided valuable insights into the TB transmission dynamics in Latvia, the genetic diversity of M. tuberculosis genotypes circulating in the country, and the distribution of drug-resistance-conferring variants among these genotypes. It also highlighted challenges in phenotypic and WGS-based DST, evaluated different WGS-based strategies for determining the causes of recurrent TB, and proposed an integrative approach for delineating TB transmission chains. These findings support the potential of integrating WGS into routine practice as part of a comprehensive local TB surveillance program.Item Changes in intraocular pressure and horizontal pupil diameter during use of topical mydriatics in the canine eye(2017) Kovalcuka, Liga; Ilgazs, Agris; Bandere, Dace; Williams, David L.; Department of Pharmaceutical ChemistryThe objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically normal canine patients (between the ages of 2 and 6 years) of varying breed and sex were used in this study. Animals were randomly divided into four groups of ten and given one drop of tropicamide, atropine, phenylephrine or saline into one eye. IOP and HPD were measured in both eyes every 5 minutes for 60 minutes. Tropicamide increased IOP by 8.8±4.0 mmHg 35 minutes post-treatment compared to pre-treatment (P<0.01) only in treated eye. IOP in the contralateral eye did not increase. With atropine the maximum increase in IOP was 2.6±2.8 mmHg at 20 minutes post treatment in the treated eye (P<0.01). IOP in the contralateral eye did not increase. Phenylephrine increased IOP by 2.3±2.1 mmHg (P<0.05) 10 minutes after treatment. Also in the untreated eye IOP increased by 2.3±2.1 mmHg, 20 minutes post-treatment. Maximum HPD in eyes treated with tropicamide occurred at 55 minutes and with atropine at 60 minutes. There were no HPD changes in the contralateral, untreated eye. Topical 10% phenylephrine showed maximal pupil dilation 60 minutes after treatment, but the HPD of the – untreated eye slightly decreased at 15 minutes, but this change only reached statistical significance at 40 min post- treatment (P<0.05). Normal saline showed no influence on IOP or HPD. The drugs investigated here show a significant increase in IOP after mydriatics.Item Chemical Profiling and Antioxidant Activity of Tanacetum vulgare L. Wild-Growing in Latvia(2023-05) Šukele, Renāte; Lauberte, Liga; Kovalcuka, Liga; Logviss, Konstantins; Bārzdiņa, Ance; Brangule, Agnese; Horváth, Zoltán Márk; Bandere, Dace; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Laboratory of Finished Dosage FormsThe Tanacetum vulgare L. (Tansy) has several ethnobotanical uses, mostly related to the essential oil and sesquiterpene lactones, whereas information regarding other compounds is scarce. This research is designed to characterize the phenolic compounds (flavonoids, phenolic acids, and tannins) to analyze the thujone (which is toxic in high concentrations) content and to detect the antioxidant activity (DPPH assay) of extracts. The main highlights of our work provide a chemical profile of phenolic compounds of T. vulgare harvested from different regions of Latvia, as well as simultaneously support the ethnomedicinal uses for wild T. vulgare through the integration of phenolic compounds as one of the value constituents of leaves and flowers. The extraction yield was 18 to 20% for leaves and 8 to 16% for flowers. The total phenol content in the extracts of T. vulgare as well as their antioxidant activity was different between collection regions and the aerial parts ranging from 134 to 218 mg GAE/g and 32 to 182 mg L−1, respectively. A remarkable variation in the thujone (α + β) content (0.4% up to 6%) was detected in the extracts. T. vulgare leaf extracts were rich in tannins (up to 19%). According to the parameters detected, the extracts of T. vulgare could be considered promising for the development of new herbal products.Item Development of Composite Sponge Scaffolds Based on Carrageenan (CRG) and Cerium Oxide Nanoparticles (CeO2 NPs) for Hemostatic Applications(2023-09-04) Kimia, Alizadeh; Dezvare, Yasaman; Kamyab, Shirin; Amirian , Jhaleh; Brangule, Agnese; Bandere, Dace; Department of Pharmaceutical ChemistryIn this study, a novel absorbable hemostatic agent was developed using carrageenan (CRG) as a natural polymer and cerium oxide nanoparticles (CeO2 NPs). CRG-CeO2-0.5 and CRG-CeO2-1 composites were prepared by compositing CeO2 to CRG + CeO2 at a weight ratio of 0.5:100 and 1:100, respectively. The physicochemical and structural properties of these compounds were studied and compared with pristine CRG. Upon incorporation of CeO2 nanoparticles into the CRG matrix, significant reductions in hydrogel degradation were observed. In addition, it was noted that CRG-CeO2 exhibited better antibacterial and hemostatic properties than CRG hydrogel without CeO2 NPs. The biocompatibility of the materials was tested using the NIH 3T3 cell line, and all samples were found to be nontoxic. Particularly, CRG-CeO2-1 demonstrated superior hemostatic effects, biocompatibility, and a lower degradation rate since more CeO2 NPs were present in the CRG matrix. Therefore, CRG-CeO2-1 has the potential to be used as a hemostatic agent and wound dressing.Item Difterijas antibakteriālā terapija: raksturojums, efektivitāte, problēmas(2008) Bandere, DaceItem Effect of NAT2, GSTM1 and CYP2E1 genetic polymorphisms on plasma concentration of isoniazid and its metabolites in patients with tuberculosis, and the assessment of exposure-response relationships(2024-03) Ulanova, Viktorija; Kivrane, Agnija; Viksna, Anda; Pahirko, Leonora; Freimane, Lauma; Sadovska, Darja; Ozere, Iveta; Cirule, Andra; Sevostjanovs, Eduards; Grinberga, Solveiga; Bandere, Dace; Ranka, Renate; Research Professor (Tenured Professor) Group at the Faculty of Pharmacy; Department of Pharmaceutical ChemistryObjectives: Isoniazid is a key drug in the chemotherapy of tuberculosis (TB), however, interindividual variability in pharmacokinetic parameters and drug plasma levels may affect drug responses including drug induced hepatotoxicity. The current study investigated the relationships between isoniazid exposure and isoniazid metabolism-related genetic factors in the context of occurrence of drug induced hepatotoxicity and TB treatment outcomes. Methods: Demographic characteristics and clinical information were collected in a prospective TB cohort study in Latvia ( N = 34). Time to sputum culture conversion (tSCC) was used as a treatment response marker. Blood plasma concentrations of isoniazid (INH) and its metabolites acetylisoniazid (AcINH) and isonicotinic acid (INA) were determined at three time points (pre-dose (0 h), 2 h and 6 h after drug intake) using liquid chromatography-tandem mass spectrometry. Genetic variations of three key INH-metabolizing enzymes (NAT2, CYP2E1, and GSTM1) were investigated by application PCR- and Next-generation sequencing-based methods. Depending on variables, group comparisons were performed by Student's t-test, one-way ANOVA, Mann-Whitney-Wilcoxon, and Kruskal-Wallis tests. Pearson correlation coefficient was calculated for the pairs of normally distributed variables; model with rank transformations were used for non-normally distributed variables. Time-to-event analysis was performed to analyze the tSCC data. The cumulative probability of tSCC was obtained using Kaplan-Meier estimators. Cox proportional hazards models were fitted to estimate hazard rate ratios of successful tSCC. Results: High TB treatment success rate (94.1%) was achieved despite the variability in INH exposure. Clinical and demographic factors were not associated with either tSCC, hepatotoxicity, or INH pharmacokinetics parameters. Correlations between plasma concentrations of INH and its metabolites were NAT2 phenotype-dependent, while GSTM1 genetic variants did not showed any effects. CYP2E1*6 (T > A) allelic variant was associated with INH pharmacokinetic parameters. Decreased level of AcINH was associated with hepatotoxicity, while decreased values of INA/INH and AcINH/INH were associated with month two sputum culture positivity. Conclusion: Our findings suggest that CYP2E1, but not GSTM1, significantly affects the INH pharmacokinetics along with NAT2. AcINH plasma level could serve as a biomarker for INH-related hepatotoxicity, and the inclusion of INH metabolite screening in TB therapeutic drug monitoring could be beneficial in clinical studies for determination of optimal dosing strategies.Item Evaluation of Antimicrobial Resistance in Clinical Isolates of Enterococcus spp. Obtained from Hospital Patients in Latvia(2024-06) Labecka, Linda; Ķibilds, Juris; Cīrulis, Aivars; Čeirāne, Evelīna Diāna; Zeltiņa, Indra; Reinis, Aigars; Vilima, Barba; Rudzīte, Dace; Erts, Renārs; Mauliņa, Inga; Bandere, Dace; Krūmiņa, Angelika; Department of Infectology; Department of Biology and Microbiology; Department of Pharmaceutical ChemistryBackground and Objective: Enterococci are typically found in a healthy human gastrointestinal tract but can cause severe infections in immunocompromised patients. Such infections are treated with antibiotics. This study addresses the rising concern of antimicrobial resistance (AMR) in Enterococci, focusing on the prevalence of vancomycin-resistant enterococcus (VRE) strains. Materials and Methods: The pilot study involved 140 Enterococci isolates collected between 2021 and 2022 from two multidisciplinary hospitals (with and without local therapeutic drug monitoring protocol of vancomycin) in Latvia. Microbiological assays and whole genome sequencing were used. AMR gene prevalence with resistance profiles were determined and the genetic relationship and outbreak evaluation were made by applying core genome multi-locus sequence typing (cgMLST). Results: The acquired genes and mutations were responsible for resistance against 10 antimicrobial classes, including 25.0% of isolates expressing resistance to vancomycin, predominantly of the vanB type. Genetic diversity among E. faecalis and E. faecium isolates was observed and seven potential outbreak clusters were identified, three of them containing sequence types ST6, ST78 and ST80. The prevalence of vancomycin resistance was highest in the hospital without a therapeutic drug-monitoring protocol and in E. faecium. Notably, a case of linezolid resistance due to a mutation was documented. Conclusions: The study illustrates the concerning prevalence of multidrug-resistant Enterococci in Latvian hospitals, showcasing the rather widespread occurrence of vancomycin-resistant strains. This highlights the urgency of implementing efficient infection control mechanisms and the need for continuous VRE surveillance in Latvia to define the scope and pattern of the problem, influencing clinical decision making and planning further preventative measures.Item Experience of Vancomycin Therapeutic Drug Monitoring in Two Multidisciplinary Hospitals in Latvia(2022-03) Mauliņa, Inga; Darbiniece, Karīna; Miķelsone-Jansone, Lāsma; Erts, Renārs; Bandere, Dace; Krūmiņa, Angelika; Department of Pharmaceutical Chemistry; Department of InfectologyBackground and Objectives: Management of infectious diseases is a huge burden to every healthcare system worldwide. Antimicrobial resistance, including antibacterial resistance, is an increasing problem worldwide; therefore, more new antibiotics are necessary to be discovered. Meanwhile, “old” antibacterial agents are still administered to fight infectious diseases caused by resistant bacteria. One of these antibacterial agents is vancomycin, which is effective in treating serious systemic infections caused by gram-positive bacteria. Thus, it is necessary to perform vancomycin concentration measurements in plasma due to its narrow therapeutic index. Various approaches are implemented for more precise therapy, including therapeutic drug monitoring (TDM) of vancomycin and with a supervision of a clinical pharmacist. The purpose of the study was to investigate if the TDM practice is improved with a local vancomycin TDM protocol applied in a hospital. The results of TDM in two multidisciplinary hospitals, one with a local TDM protocol implemented and applied and the other with no local TDM protocol implemented and applied, were compared. Materials and Methods: A retrospective study was performed in two multidisciplinary hospitals in Latvia. The data were collected for a time period of 4 years (2016–2020) in a hospital without a local TDM protocol and for a time period of 2 years (2018–2020) in a hospital with a local TDM protocol, starting with a period of time when the vancomycin TDM protocol was developed. The data about the patients included in the study were analyzed based on gender, age, body weight, and renal function. Vancomycin therapy was analyzed based on dosing schemes (vancomycin dose and dosing interval), data about loading and maintenance doses, vancomycin concentration, and details about vancomycin concentration (sampling time and concentration level). Results: Differences between the hospitals were found in terms of the initiation of vancomycin administration and concentration sampling. In the hospital with a TDM protocol compared with the hospital without a TDM protocol, more accurate initiation was found, alongside adaption of therapy (97.22% vs. 18.95%, p < 0.001), better performance of administration of a loading dose (22.73% vs. 1.29%, p < 0.01), and reaching of target concentration (55.56% vs. 35.29%, p < 0.01). Concentration sampling in the correct timeframe before the vancomycin dose and vancomycin administration did not show statistically better results in either of the hospitals (4.60% vs. 6.29%, p = 0.786). Conclusions: Better results of adequate adjustments of vancomycin therapy were achieved in the hospital with a TDM protocol. In the long term, sustainable results and regular medical professionals’ training is necessary.Item From Polymeric Nanoformulations to Polyphenols - Strategies for Enhancing the Efficacy and Drug Delivery of Gentamicin(2024-04) Bārzdiņa, Ance; Plotniece, Aiva; Sobolev, Arkadij; Pajuste, Karlis; Bandere, Dace; Brangule, Agnese; Department of Pharmaceutical ChemistryGentamicin is an essential broad-spectrum aminoglycoside antibiotic that is used in over 40 clinical conditions and has shown activity against a wide range of nosocomial, biofilm-forming, multi-drug resistant bacteria. Nevertheless, the low cellular penetration and serious side effects of gentamicin, as well as the fear of the development of antibacterial resistance, has led to a search for ways to circumvent these obstacles. This review provides an overview of the chemical and pharmacological properties of gentamicin and offers six different strategies (the isolation of specific types of gentamicin, encapsulation in polymeric nanoparticles, hydrophobization of the gentamicin molecule, and combinations of gentamicin with other antibiotics, polyphenols, and natural products) that aim to enhance the drug delivery and antibacterial activity of gentamicin. In addition, factors influencing the synthesis of gentamicin-loaded polymeric (poly (lactic-co-glycolic acid) (PLGA) and chitosan) nanoparticles and the methods used in drug release studies are discussed. Potential research directions and future perspectives for gentamicin-loaded drug delivery systems are given.