School of Medical Sciences

Immunocompromised hosts

Principal investigator


We have focused on the clinical and therapeutic aspects of infections occurring in the immunocompromised host, particularly those patients with HIV infection. The research is predominantly based in the clinic, including participation in multicentre studies, but a number of local trials have been established, as well as collaboration with more laboratory-centred research groups.

Investigation of the characteristics of disease in HIV-infected persons

The clinical presentation, results of investigation and responses to treatment of HIV-infected patients with a variety of clinical problems have been investigated. We have contributed to a number of international collaborations investigating antiretroviral treatment including the DELTA, OZCOMBO, CREST, INITIO and SECONDLINE studies. We have also collaborated with local investigators in studies of bone mineral density in HIV-infected patients. We have reported excellent results with a relatively low-dose TMP-SMX treatment of PJP in HIV-infected patients. We have studied a number of health psychology issues related to HIV infection including treatment adherence and the psychological effects of lipodystrophy.

Investigation of the characteristics of a variety of other infections

The clinical presentation, results of investigation and responses to treatment of miscellaneous infectious diseases have been studied. We have focused on infections involving the CNS and on infections due to N. meningitidis or S. aureus. We have published on: treatment of meningococcal disease with IV benzyl penicillin given for 3 days; S.aureus bacteraemia in hospitalised patients in Auckland; S. aureus meningitis; bacterial meningitis following neurosurgical procedures; P. acnes post-neurosurgical infections and tuberculous meningitis.

Infections in the immunocompromised host

We are interested in the diagnosis and management of infection in non-HIV infected immunocompromised patients, including fungal infections in haematology-oncology patients, therapy of neutropenic fever and opportunistic infections in patients following liver, bone marrow or renal transplantation.

Antimicrobial stewardship and relationship to antimicrobial resistance

We are investigating the level of consumption of antimicrobial agents in community and hospital care in New Zealand to develop instruments to foster prudent use of antimicrobials to delay the spread of antimicrobial resistance.

Recent relevant publications

  1. Briggs, S., Ellis-Pegler, R. B., Raymond, N., Thomas, M.G., Wilkinson, L. (2004). Gram-negative bacillary meningitis after cranial surgery or trauma in adults. Scandinavian Journal of Infectious Diseases, 36:165-173.
  2. Briggs, S., Ellis-Pegler, R. B., Roberts, S., Thomas, M.G., Woodhouse, A. (2004). Short course intravenous benzylpenicillin treatment of adults with meningococcal disease. Internal Medicine Journal, 34: 383-387.
  3. Thomas, M.G., Morris, A.J. (2005). Cannula-associated Staphylococcus aureus bacteraemia: outcome in relation to treatment. Internal Medicine Journal, 35 (6): 315-318.
  4. Thomas, M.G., Woodfield, D.G., Moses, C., Amos, G. (2005). Soil-transmitted helminth infection, anaemia, and growth retardation in schoolchildren of Taveuni Island, Fiji. New Zealand Medical Journal, 118:1-12.
  5. Yang, L.P., Thomas, M.G., Woodhouse, A., Martin, D., Fraser, J.D., Proft, T.K. (2005). Involvement of streptococcal mitogenic exotoxin Z in streptococcal toxic shock syndrome. Journal of Clinical Microbiology, 43: 3570-3573. Note: corresponding author.
  6. Thomas, M.G., Nisbet, M. (2005). Liver abscess associated with persistent Streptococcus anginosus bacteremia. Clinical Infectious Diseases, 41: 403-405.
  7. Bolland, M.J., Grey, A.B., Horne, A.M., Briggs, S., Thomas, M.G., Ellis-Pegler, R., Woodhouse, A., Gamble, G.D., Reid, I.R. (2006). Bone mineral density is not reduced in HIV-infected Caucasian men receiving highly active antiretroviral therapy. Clinical Endocrinology, 65: 191-197.
  8. Ritchie, S.R., Rupali, P., Roberts, S.A., Thomas, M.G. (2007). Flucloxacillin treatment of Staphylococcus aureus meningitis.  European Journal of Clinical Microbiology & Infectious Diseases, 26: 501-504, 2007.
  9. Nisbet, M., Briggs, S., Ellis-Pegler, R.B., Thomas, M.G., Holland, D.J. (2007). Proprionibacterium acnes: an under-appreciated cause of post-neurosurgical infection. Journal of Antimicrobial Chemotherapy, 60 (5): 1097-1103.
  10. Bolland, M.J., Grey, A.B., Horne, A.M., Briggs, S.E., Thomas, M.G., Ellis-Pegler, R.B., Woodhouse, A.F., Gamble, G.D., Reid, I.R. (2007). Bone mineral density remains stable in HAART-treated HIV-infected men over 2 years. Clinical Endocrinology, 67: 270-275.
  11. Fu, J., Thomas, M.G. (2007). Two cases of endocarditis due to Bartonella henselae. New Zealand Medical Journal, 120 (1255): 1-5.
  12. Rupali, P., Condon, R., Roberts, S.A., Wilkinson, L., Voss, L.M., Thomas, M.G. (2007). Prevention of mother to child transmission of HIV infection in Pacific countries. Internal Medicine Journal, 37: 216-223.
  13. Nisbet, S.M., Reeve, M., Ellis-Pegler, R.B., Woodhouse, A., Ingram, J., Roberts, S., McAllister, S., Thomas, M.G. (2007). Good outcome in HIV infected refugees after resettlement in New Zealand. Internal Medicine Journal, 37: 290-294.
  14. McManus, T., Thomas, M.G., Rogers, D., Harrison, A. (2009). Pleuropulmonary paragonimiasis. Internal Medicine Journal. 39 (3): 203.
  15. Plowman, G.M., Watson, M.W., D'Souza, H., Thomas, M.G. (2009). Obstructive endo-bronchial pseudotumour due to Herpes simplex type 2 infection in an HIV infected man. International Journal of STD & AIDS, 20: 737-738.
  16. Dittmer, I.D., Williams, L.C., Carpenter, L.D., Croxson, K., Thomas, M.G., Pilmore, H., Collins, J.D., Thomas, S.M. (2009). Fatal human herpesvirus-6 infection after renal transplantation. Transplantation, 88 (6): 762-765.
  17. Thomas, M.G., Rupali, P., Woodhouse, A., Ellis-Pegler, R.B. (2009). Good outcome with trimethoprim 10 mg/kg/day-sulphamethoxazole 50 mg/kg/day for Pneumocystis jirovecii pneumonia in HIV infected patients. Scandinavian Journal of Infectious Diseases, 4: 1862-868.
  18. Anderson, N.E., Somaratne, J., Mason, D.F., Holland, D., Thomas, M.G. (2010). Neurological and systemic complications of tuberculous meningitis and its treatment at Auckland City Hospital, New Zealand. Journal of Clinical Neuroscience, 17: 1114-1118.
  19. Anderson, N.E., Somaratne, J., Mason, D.F., Holland, D., Thomas, M.G. (2010) A review of tuberculous meningitis at Auckland City Hospital, New Zealand. Journal of Clinical Neuroscience, 17: 1018-1022.