Pseudomonas aeruginosa transmission is infrequent in New Zealand cystic fibrosis clinics

¹ Institute of Molecular Biosciences, Massey University, Palmerston North
² Dept of Medicine, University of Auckland, Auckland
³ Paediatric Gastroenterology Service, Starship Children's Health, Auckland
⁴ Dept of Infectious Disease, Waikato Hospital, Hamilton
⁵ Dept of Paediatrics, Palmerston North Hospital, Palmerston North
⁶ Respiratory Medicine, Wellington Hospital, Wellington
⁷ Respiratory Services, Christchurch Hospital, Christchurch
⁸ Dept of Paediatrics, University of Otago – Christchurch
⁹ Otago Respiratory Research Unit, University of Otago – Dunedin
¹⁰ Dept of Paediatrics and Child Health, University of Otago - Wellington, New Zealand

^* To whom correspondence should be addressed. E-mail: Keith_Grimwood{at}health.qld.gov.au.

	Abstract

Pseudomonas aeruginosa is an important pathogen in cystic fibrosis (CF). Although most patients harbour unique P. aeruginosa isolates, some clinics report patients sharing common strains. The overall importance of person-to-person transmission in P. aeruginosa acquisition and whether routine patient segregation is necessary remains uncertain. We therefore investigated the extent of P. aeruginosa transmission in New Zealand CF clinics.

We assessed New Zealand's seven major CF centres, combining epidemiological data with computer-assisted SalI DNA fingerprinting of 496 isolates from 102 patients.

One cluster of related isolates was significantly more prevalent in the largest clinic than expected by chance. The seven patients with isolates belonging to this cluster had more contact with each other than the remaining patients attending this centre. We found no other convincing evidence of transmission in any of the other smaller clinics. Three P. aeruginosa strains believed to be transmissible between patients in Australian and British CF clinics are present in New Zealand, but there was no definite evidence they had spread.

P. aeruginosa transmission is currently infrequent in New Zealand CF clinics. This situation could change rapidly and ongoing surveillance is required. Our results confirm that computer-assisted SalI DNA fingerprinting is ideally suited for such surveillance.