Recent Graduations

By dhadmin
Monday, 13th November 2017
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Congratulations to Alexandros Lazaris and to Grainne Brennan on recently completing their Ph.D.s under the supervision of Professor David Coleman and Dr. Anna Shore from the Division of Oral Biosciences, Microbiology Research Unit.

Alex’s Ph.D. involved investigated the molecular mechanisms of emerging antibiotic resistance in Staphylococcis aureus and coagulase-negative staphylococci (CoNS) in hospitalised patients in Ireland in recent years. Using whole genome sequencing he identified the presence of a variety of novel plasmids in MRSA and CoNS encoding resistance to the antibiotic linezolid encoded by the cfr and fexA genes, an antibiotic of last resort. This work included the first report of cfr in the pandemic MRSA clones ST22. He also identified for the first time a unique combination of the cfr and optrA resistance genes co-located on a single plasmid in vancomycin resistant Enterococcus faecium. Alex also identified a range of distinct plasmids in MRSA harbouring the ileS2 gene encoding resistance to the antibiotic mupirocin. Mupirocin is one of the few antibiotics available to eradicate S. aureus colonization. Many of the plasmides encoding cfr or ileS2 harboured additional resistance genes, indicating that the overuse of linezolid and mupirocin can exert selective pressure for retention of antibiotic resistance genes in Irish hospitals. Alex’s research during his Ph.D. contrubuted to four publications in peer-reviewed international journals.

Gráinne’s Ph.D. involved the molecular characterisation of unusual methicillin-resistant Staphylococcus aureus (MRSA) strains that have emerged in Ireland and revealed evidence of the importation and spread of a diverse range of MRSA among and between animals and humans, both in hospitals and in the community. She also identified the increasing prevalence of fusC-encoded fusidic acid resistance among MRSA here. Using whole-genome sequencing she identified seven novel combinations of the methicillin resistance gene mecA and fusC mobile staphylococcal cassette chromosome mec elements in these isolates. Lastly, during her  Ph.D. Gráinne evaluated the usefulness of whole-genome sequencing and DNA microarrays for MRSA typing and chromogenic agar for the detection of MRSA. To date, Gráinne’s research during her Ph.D. contributed to six publications in peer-reviewed international journals.

Congratulations to Keira Malone who graduated from The University of Dublin with her Doctorate (DCh Dent Oral Surgery) on Friday 10th November 2017.

Pictured in the photos are Grainne Brennan, Alex Lazaris and Keira Malone.