Identification and determination of virulence factors of invasive ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด sensu lato in paediatric patients at Universitas Academic Hospital
| dc.contributor.advisor | Pohl-Albertyn, Carolina H. | en_ZA |
| dc.contributor.advisor | Albertyn, J. | en_ZA |
| dc.contributor.advisor | Musoke, Jolly | en_ZA |
| dc.contributor.advisor | Mosia, B. | en_ZA |
| dc.contributor.author | Moncho, Masego MaryJane | en_ZA |
| dc.date.accessioned | 2025-01-03T11:18:33Z | |
| dc.date.available | 2025-01-03T11:18:33Z | |
| dc.date.issued | 2024 | en_ZA |
| dc.description | Thesis (Ph.D.(Medical Microbiology))--University of the Free State, 2024 | en_ZA |
| dc.description.abstract | ๐๐ป๐๐ฟ๐ผ๐ฑ๐๐ฐ๐๐ถ๐ผ๐ป: Invasive fungal infections contribute to a rise in morbidity and mortality, extended stay in hospital and higher health care cost. Due to the increased risk factors among the neonates, this population continues to bear the brunt as the morbidity and mortality due to ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด remains high. This is further complicated by the rising predominance of azole-resistant strains. ๐๐ถ๐บ: This study aimed to identify the specific strains of C. ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด ๐ด๐ฆ๐ฏ๐ด๐ถ ๐ญ๐ข๐ต๐ฐ cultured from neonatal and paediatric patients at Universitas Academic Hospital and to determine their virulence potential. The clinical outcome data of the patients were correlated with the strainsโ data. ๐ ๐ฒ๐๐ต๐ผ๐ฑ๐ผ๐น๐ผ๐ด๐: The study was conducted at the Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein. This was a retrospective cross-sectional laboratory-based study. ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด as identified on Vitekยฎ2 (bioMรฉrieux Inc, Marcy lโEtoile, France), from invasive clinical samples sent for routine laboratory diagnosis to the Medical Microbiology laboratory from Universitas Hospitalโs neonatal and paediatric wards, were used. A sample size of approximately 30 was estimated based on the numbers from the previous yearโs however, only 21 strains were obtained, with one of the patients having two isolates. Therefore, 20 patientsโ strains were obtained. The ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด strains used for the study were those already stored in the laboratory at -80ยฐC from the year 2018 to 2020. Data obtained from Vitekยฎ2 (bioMรฉrieux Inc, Marcy lโEtoile, France) as well as patientsโ demographic data and clinical information from patient clinical files were recorded on an Excel sheet for analysis. No patient names were recorded. Only study numbers were used. D1/D2 sequencing was performed for species differentiation. Clinical records were reviewed, time to positivity, species identification, antifungal susceptibility testing results and patientsโ demographics were also retrieved from TrackCare. The QualiClean (QualiPharm, New Germany) used in the hospital setting at 1000 ppm for surface disinfection was tested against all the 20 strains to determine their susceptibility to the disinfectant. A crystal violet assay was conducted to determine biomasses of respective biofilms. For hydrolytic enzymes secretion, tributyrin agar was used for lipase activity, yeast carbon base bovine serum albumin agar for protease activity and the sabauraud dextrose agar supplemented with 8% egg yolk for phospholipase activity. Prostaglandin E2 production was evaluated by using the enzyme-linked immunosorbent assay (ELISA; Cayman Chemicals, Ann Arbour, USA) according to the manufacturerโs instructions. The biological method described by Brenner (Brenner, 1974) was followed for ๐ช๐ฏ ๐ท๐ช๐ท๐ฐ relative virulence in ๐๐ข๐ฆ๐ฏ๐ฐ๐ณ๐ฉ๐ข๐ฃ๐ฅ๐ช๐ต๐ช๐ด ๐ฆ๐ญ๐ฆ๐จ๐ข๐ฏ๐ด In addition, whole genome sequencing was conducted to study the ploidy of the study strains, genetic relatedness as well as the common antifungal resistance genes. ๐ฅ๐ฒ๐๐๐น๐๐: The strains were all ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด ๐ด๐ฆ๐ฏ๐ด๐ถ ๐ด๐ต๐ณ๐ช๐ค๐ต๐ฐ. Ninety percent of blood cultures had a time to positivity of 48 hours with 80% of the strains showing resistance to fluconazole and the intermediate resistance to voriconazole. For 70% of the strains, resistance to fluconazole and intermediate resistance to voriconazole was observed. In addition, the QualiClean disinfectant did not effectively inhibit any of the strains. Fifty-five percent of the patients were from neonatal intensive care unit followed by 35% from neonatal high care and 10% from paediatric wards. Eighty percent of the patients were males. Forty-one percent of the patients were categorized as very low birth weight and 55% delivered via caesarian section. The study population had multiple risk factors including the presence of invasive devices, total parenteral nutrition, gastrointestinal pathology, and administration of broad-spectrum antibiotics. Deaths were recorded for 47% of the patients. The strains produced biofilms, proteases, phospholipases, and prostaglandin Eโ in varying quantities. The three C. ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด strains tested for their virulence in C. ๐ฆ๐ญ๐ฆ๐จ๐ข๐ฏ๐ด, killed the nematodes rapidly when compared to the C. ๐ข๐ญ๐ฃ๐ช๐ค๐ข๐ฏ๐ด ATCC SC5314 strain. All strains were haploid and were found to group into four related Clades, with majority of the strains in Clade 4. Clade 4 also housed 94% of the fluconazoleresistant strains. The ๐๐๐1, ๐๐๐1 and ๐๐๐11 genes were highly conserved between strains with none of the mutations previously associated with resistance patterns. ๐๐ผ๐ป๐ฐ๐น๐๐๐ถ๐ผ๐ป: ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด ๐ด๐ฆ๐ฏ๐ด๐ถ ๐ด๐ต๐ณ๐ช๐ค๐ต๐ฐ is circulating with majority of strains resistant to fluconazole, suggesting that fluconazole should be avoided as the empiric therapy among this population. All strains were virulent and resisted the action of the disinfectant. The contact time will need to be increased or a different disinfectant used. Multiple infection prevention and control interventions including hand hygiene are also to be intensified. Further studies are required to identify the resistance mutations or novel mutations prevalent at the study site, including those outside the common regions. | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11660/12901 | |
| dc.language.iso | en | |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Candidemia | en_ZA |
| dc.subject | ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด | en_ZA |
| dc.subject | Virulence factors | en_ZA |
| dc.subject | Hydrolytic enzymes | en_ZA |
| dc.subject | Prostaglandin Eโ | en_ZA |
| dc.subject | Biofilm formation | en_ZA |
| dc.subject | Chlorine based disinfectant | en_ZA |
| dc.subject | ๐๐ข๐ฆ๐ฏ๐ฐ๐ณ๐ฉ๐ข๐ฃ๐ฅ๐ช๐ต๐ช๐ด ๐ฆ๐ญ๐ฆ๐จ๐ข๐ฏ๐ด | en_ZA |
| dc.subject | Whole genome sequencing | en_ZA |
| dc.subject | Ploidy | en_ZA |
| dc.title | Identification and determination of virulence factors of invasive ๐๐ข๐ฏ๐ฅ๐ช๐ฅ๐ข ๐ฑ๐ข๐ณ๐ข๐ฑ๐ด๐ช๐ญ๐ฐ๐ด๐ช๐ด sensu lato in paediatric patients at Universitas Academic Hospital | en_ZA |
| dc.type | Thesis |