RSU e-resource repository

Rīga Stradiņš University institutional open access e-resource repository on DSpace platform stores different types of digital and digitized materials created by RSU:

  • the results of scientific and academic activities (articles and monographs)
  • didactic and informative materials
  • doctoral theses and students' final theses
  • conference materials
  • other resources

Instruction to access doctoral theses and students' final theses

 

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Streptococcus pneumoniae serotypes and factors associated with antimicrobial resistance in Invasive pneumococcal disease cases in Latvia, 2012–2022
(2025-03-12) Savrasova, Larisa; Villeruša, Anita; Zeltiņa, Indra; Krūmiņa, Angelika; Čupeca, Hedija; Balasegaram, Sooria; Grēve, Māra; Savicka, Oksana; Selderina, Solvita; Galajeva, Jelena; Dushacka, Diana; Institute of Public Health; Department of Infectology; Department of Human Physiology and Biochemistry; Statistics Unit
Background: Streptococcus pneumoniae is a major cause of Invasive pneumococcal disease (IPD), including bacteremic pneumonia, septicemia, and meningitis. The introduction of pneumococcal conjugate vaccines (PCVs) has significantly reduced the incidence of IPD caused by vaccine-covered serotypes. However, serotype replacement and antimicrobial resistance remain concerns. In Latvia, vaccination against pneumococcal disease was introduced into the NIP in 2010 with PCV7, later transitioning to PCV10 in 2012 and to PCV15 in 2024. This study aims is to determine the changes in S. pneumoniae antimicrobial resistance and its association with PCV10 serotypes in Latvia. Materials and methods: We conducted a population-based cross-sectional study using IPD surveillance data from Latvia over an 11-year period (2012–2022). IPD cases were defined according to the European Union case definition. Serotyping and antimicrobial susceptibility testing were performed on isolates from normally sterile sites. We analyzed the differences in IPD incidence, serotype distribution, and antimicrobial resistance using chi-square tests and multivariable logistic regression was used to determine associations between antimicrobial resistance and risk factors. Results: A total of 811 IPD cases were reported, with significant differences observed across the study period (p < 0.001). The most common serotypes were 3 and 19A. The proportion of IPD cases caused by PCV10 serotypes significantly decreased over the years, while cases caused by PCV13, PCV15, and PPPV23 serotypes increased. Antimicrobial susceptibility testing revealed resistance rates of 3.8% to penicillin, 5.4% to erythromycin, and 1.2% to cefotaxime/ceftriaxone. Erythromycin resistance showed significant variation over time (p = 0.016), decreasing from 7.1% in 2012 to 4.8% in 2022. Multivariable logistic regression indicated that IPD cases with S. pneumoniae PCV10 serotypes and meningitis were significantly associated with an increased likelihood of penicillin and erythromycin resistance. Conclusion: The study highlights a decrease in erythromycin resistance in IPD cases over time and significant associations between PCV10 serotypes and meningitis in IPD cases and penicillin and erythromycin resistance. The findings underscore the importance of continuous surveillance of S. pneumoniae serotypes and antimicrobial resistance patterns to inform treatment guidelines and vaccination policies. Further research is needed to assess the long-term impact of the PCV15 vaccine on S. pneumoniae serotype distribution and resistance.
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Mandibular chondroblastic type osteosarcoma primarily diagnosed as chondrosarcoma as a result of radiation therapy : a case report
(2025-03) Rone, Alise Elizabete; Bāgante, Ieva; Vasilcenko, Irina; Zariņš, Jānis; Deksnis, Renārs; Hasnere, Sigita; Department of Oral and Maxillofacial Surgery and Oral Medicine
Radiation therapy is a recognized etiological factor for osteomyelitis, osteoradionecrosis and multiple sarcomas such as chondrosarcoma and osteosarcoma. Here we present a case of mandibular chondroblastic type osteosarcoma induced by radiotherapy which was primarily misdiagnosed as chondrosarcoma. A female presented with main complaint of pain at the extraction site following multiple teeth extraction and sequestrectomy on the right lower jaw. Medical history revealed stage IV squamous cell carcinoma of the base of the tongue which was treated by surgical excision, chemotherapy and radiotherapy ten years ago. Four recurring sequestrectomies were performed, but only histological material from the fourth sequestrectomy revealed grade 2 chondrosarcoma. This was followed by resection of the tumour and floor of the mouth, mandibular, lip and facial skin reconstruction and operation material through histology was again confirmed to be grade 2 chondrosarcomas. In a year’s time, pathological nodule in thyroid gland was found on CT, surgery was performed. Operation material now revealed high grade chondroblastic type osteosarcoma and additional radiotherapy and chemotherapy was prescribed. This case illustrated chondrosarcoma and chondroblastic type osteosarcoma as a rare malignant incidence, with diagnostical difficulties and treatment. Differential diagnosis should be considered if no positive changes are observed after the designated therapy as well as importance of immunohistological evaluation. One treated malignancy does not exclude development of another unrelated malignancy.