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  • Author: Edvīns Miklaševičs x
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First Detection of Vancomycin Resistant Enterococcus faecium in Latvia

Enterococci have become one of the most important nosocomial pathogens in advanced treatment facilities. Though they are not considered as very pathogenic bacteria, their high levels of antimicrobial resistance are the subject of major concern. Particularly epidemiologically important are vancomycin-resistant enterococci (VRE) due to high risk of transmission of vancomycin resistance genes to staphylococci. We describe the first outbreak of VRE in a Latvian multidisciplinary hospital.

Abstract

Incidence of colorectal cancer is high worldwide and it mostly occurs as an accumulation of environmental factors and genetic alterations. Hereditary colorectal cancer can develop as a part of a hereditary syndrome. There is a suspected correlation between colorectal cancer and allelic variants of the POLE and POLD1 genes. The aim of the present study was to look for associations between the allelic variants in the POLE and POLD1 genes and colorectal cancer. One thousand, seven hundred and forty-nine DNA samples from colorectal cancer patients were collected from 2002 to 2013. Samples were divided in three groups: hereditary colorectal cancer patients, patients with different hereditary cancer syndromes in their families and patients with no cancer history in their families. The DNA samples were screened for allelic variants of POLE rs483352909 and POLD1 rs39751463 using denaturing high performance liquid chromatography (DHPLC). All patients were negative for allelic variants rs483352909 of the POLE gene and rs397514632 of the POLD1 gene. One allelic variant rs373243003 in the POLE gene and one novel duplication of four nucleotides at the excision site between intron and exon (c.1384-5dupCCTA) in the POLD1 gene, was found. We could not detect or confirm the connection between the genetic variants in the POLD1 and POLE genes and colorectal cancer patients, but we detected a novel genetic variant with an unknown significance.

Abstract

Development of chemoresistance remains a significant limitation for the treatment of cancer and contributes to recurrence of the disease. Both intrinsic and acquired mechanisms of chemoresistance are characteristics of cancer stem cells (CSCs) or stem-like cells (SLCs). The aim of the study was to assess the stem-like properties in the breast cancer cell line MDA-MB-231 during and after pulsed treatment with doxorubicin (DOX) in comparison to the untreated controls.The experimental cultures were exposed to therapeutic concentration of DOX for 48 hours (treatment cultures), and subcultured to post-treatment cultures 24 hours after the removal of DOX. Stem-like properties of the cellular populations in the treatment and post--treatment cultures were assessed by the expression of the stem-cell marker genes (CD24, CD44, ITGA6, ITGB1, POU5F1, NANOG, ALDH1A1), colony-formation efficiency, growth rates, and sensitivity to DOX, 5-fluorouracil (5FU), cisplatin (CIS), and vinblastine (VBL). Exposure to DOX induced formation of giant polyploid cells that persisted in the post-treatment culture. The recovery period was characterised by a decrease in the proliferation rate, viability, and cellular adherence. The post-treatment cultures displayed decreased sensitivity to DOX and increased sensitivities to 5FU, CIS, and VBL. Cells treated with DOX displayed increased expression levels of CD24, CD44, and ALDH1A, while their expression levels at least partially normalised in the post-treatment culture. The post-treatment cultures demonstrated significantly increased colony-formation ability. During treatment with sub-lethal levels of doxorubicin and during the acute recovery period, the survival mechanisms in the breast cancer cell line MDA-MB-231 may be mediated by formation of the cellular population with stem-like properties.

Abstract

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is a highly resistant and difficult to cure zoonotic microorganism, which makes up a large part of food toxic infections and has shown high prevalence among pig population all over the world. The aim of the study was to establish the occurrence of MRSA in slaughterhouses, evaluate its antimicrobial resistance, and verify whether there are any differences or similarities with reference to other European countries. Material and Methods: A total of 100 pigs, 105 carcasses, 19 workers, and 24 samples from the environment of several slaughterhouses were examined by conventional microbial and molecular methods. Results: In total, 78 MRSA isolates were found. MRSA prevalence in slaughtered pigs varied from 8.0% to 88.6% depending on the slaughterhouse, reaching higher prevalence in slaughterhouses with higher slaughter capacity. In total, 21.1% of all workers were carriers of MRSA and 6.7% of carcasses were contaminated with MRSA. The 98.2% of MRSA isolates were resistant to penicillin, 89.1% to tetracycline, 60.1% to erythromycin, 65.5% to gentamycin, and 15 different spa types were found, among which spa type t01333 was most widespread. Conclusion: The study indicated that MRSA prevalence and spa types differed according to slaughterhouse slaughter capacity and good hygiene practices. Quite high MRSA occurrence among slaughterhouse workers is one of the main factors which increase pork contamination risk.

Abstract

In developed and developing countries, most cases of acute gastroenteritis in children are caused by viruses, and rotaviruses are known as the leading cause. The aim of our study was to estimate the main circulating serotypes of rotavirus before the introduction of routine immunisation in Latvia, and to search for their possible correlation with clinical symptoms and circulating genotypes. A cross-sectional study was carried out among children who had been hospitalised in the Children’s Clinical University Hospital from April 2013 to December 2015. Genotyping was done for 462 stool samples. Among G/P combinations, the most predominant genotypes were G4P[8] (61.3%), G9P[8] (12.4%) and G2P[4] (10.0%) in children of age < 5 years, G4P[8] (45.5%), G2P[4] (18.2%), G9P[8], G3P[8], and G1P[8] (9.1%) in children of age > 5 years. There was a statistically significant correlation (p < 0.05) between clinical signs (vomiting, dehydration, chronic diseases) and G1P[8] and G8P[8] genotypes. Infants infected with genotype G4P[4] had a statistically significant negative correlation with severity of acute gastroenteritis episodes (p < 0.05). We detected nine different rotavirus G genotypes, and two different P genotypes. G4P[8], G9P[8], and G2P[8] were predominant. We observed correlation between the dominant genotypes and clinical manifestations of rotavirus infection.

Abstract

The aim of the study was to evaluate the role of ultrasound guided fine needle aspiration cytology (FNAC) in the restaging of node positive breast cancer after neoadjuvant chemotherapy (NAC). From January 2016 – October 2018, 90 node positive stage IIA-IIIC breast cancer cases undergoing NAC were included in the study. The largest, most superficial and the most caudal axillary node metastasis confirmed by fine needle aspiration cytology (FNAC) was marked with clip. After NAC, restaging of axilla was performed with ultrasound and FNAC of the marked and/or the most suspicious axillary node. Of the 90 cases, 58 with available ultrasound guided percutaneous needle biopsy data were further evaluated. Axilla conserving surgery was performed in 37 of 58 cases and axillary lymph node dissection (ALND) in 21 of 58 cases. False Positive Rate (FPR) of FNAC after NAC was 12%, False Negative Rate (FNR) — 58%, sensitivity — 54%, specificity — 82%, accuracy 62%. FNAC after NAC had low FPR and was found to be useful in predicting residual axillary disease and to streamline surgical decision making regarding ALND. However, FNR was unacceptably high and FNAC alone was not able to predict ypCR and omission of further axillary surgery.

Epidemiological, Clinical, Molecular Features and Early Detection Strategy of Most Frequent Hereditary Cancers in Latvia

The aim of the study was to determine epidemiological, clinical and molecular features of hereditary breast-ovarian, colorectal, endometrial, prostate and pancreatic cancer in Latvia. The study was performed from 2006 to 2009. Family cancer histories and DNA samples from 5,040 cancer cases were collected, and more than 6,000 molecular tests were performed including multiplex PCR, direct sequencing, denaturing high performance liquid chromatography and others. For the first time, a BRCA2 gene mutation positive hereditary breast cancer family was identified. The necessity of 2 BRCA1 gene founder mutations testing, irrespective of family cancer history for breast and ovarian cancer patients, was confirmed on a large number of positive cases. Regarding hereditary ovarian cancer, every ninth case affected with this malignancy was associated with the BRCA1 gene mutation. For the first time, positive familial adenomatous polyposis cases positive for APC gene mutation were reported and data on the clinical frequency of hereditary endometrial and prostate cancer were provided. In pancreatic cancer patients there was a 3.5% frequency of BRCA1 gene founder mutations.