Evidence for a pseudo-outbreak of Candida guilliermondii fungemia in a university hospital in Brazil

Abstract

Fungal infections due to Candida species represent an important cause of nosocomial bloodstream infections. We report a large pseudo-outbreak of Candida guilliermondii fungemia that occurred in a university hospital in Brazil. C. guilliermondii was identified in 64 (43%) of the 149 blood samples drawn between June 2003 and July 2004. The samples were from patients in different wards of the hospital but concentrated in pediatric units. None of the patients had clinical signs of fungemia, and observational analysis revealed errors in the collection of blood samples. During the investigation of the pseudo-outbreak, C. guilliermondii was isolated from environmental surfaces and from the skin and nails of members of the nursing team. Through a subtyping analysis it was found that some of the nonpatient isolates were highly related to the patient isolates, and all the patient isolates were highly related. This is consistent with the hypothesis that the pseudo-outbreak was from a limited number of common sources. The adoption of intervention measures was effective in resolving the outbreak, supporting the hypothesis that the outbreak was due to poor techniques of drawing blood samples for culture.

FIG. 1.

Distribution of C. guilliermondii cases isolated at the Hospital São Paulo, São Paulo, Brazil, from April 2003 to July 2004 and intervention measures. The numbers on the y axis and in the bars are the numbers of cases.

FIG. 2.

RAPD fingerprints of Brazilian cluster strains using primer UBC738 or 405627. (A) South American control and U.S. control strains. (B) U.S. control and Brazilian outbreak strains 2004010446 to 2004010450 (21 to 25, respectively, in text). The white arrow indicates the absence of bands for isolates 22 to 24. (C) Brazilian outbreak strains 2004010326 to 2004010337 (strains 1 to 12, respectively, in text). I to III in the lanes show examples of the three representative groups. M, molecular size markers.

FIG. 3.

HinfI digestion pattern B for five environmental isolates in the Brazilian cluster strains. Molecular sizes (in kilobases) are shown at the sides of the gel.

FIG. 4.

Cluster analysis of RAPD fingerprint patterns obtained with primers UBC147 and UBC738 by the unweighted-pair group method using average linkages. The 29 nonoutbreak strains and three examples of the outbreak strains are shown. Roman numerals I to III correspond to the three major taxonomic groups. Percent relatedness is shown on the horizontal axis.