Genetic similarity of Burkholderia cenocepacia from cystic fibrosis patients.

Burkholderia cenocepacia may cause serious infections in patients with cystic fibrosis, and this microorganism can be highly transmissible. Pulsed-field gel electrophoresis is widely used to study the dynamics of strain spread in cystic fibrosis patients. The aim of this work was to perform pulsed-field gel electrophoresis-based molecular typing of B. cenocepacia isolates to evaluate the epidemiology of this species at our hospital. A total of 28 isolates from 23 cystic fibrosis patients were analyzed. Initially, we compared isolates obtained from the same patient at different periods of time. We then compared the pulsed-field gel electrophoresis profiles of 15 IIIA isolates, and in a third analysis, evaluated the genetic profile of 8 IIIB isolates from different patients. The pulsed-field gel electrophoresis profiles of isolates from the same patient indicated that they are genetically indistinguishable. Analysis of isolates from different patients revealed the presence of multiple clonal groups. These results do not indicate cross-transmission of a unique clone of B. cenocepacia among cystic fibrosis patients, although this has been observed in some patients. Our findings highlight the importance of adequate patient follow-up at cystic fibrosis centers and adherence to management and segregation measures in cystic fibrosis patients colonized with B. cenocepacia.

Distribution of staphylococcal cassette chromosome mec (SCCmec) types I, II, III and IV in coagulase-negative staphylococci from patients attending a tertiary hospital in southern Brazil.

Coagulase-negative staphylococci (CoNS) are now recognized as the aetiological agents of an important range of infections in humans. Most developed countries have reported an increase in CoNS infections in hospitalized patients that are resistant to meticillin and other antibiotics. Staphylococcal cassette chromosome mec (SCCmec) typing is essential for understanding the molecular epidemiology of meticillin-resistant Staphylococcus strains. SCCmec elements are currently classified into types I to VI based on the characteristics of the mec and ccr gene complexes and are further classified into subtypes according to their 'junkyard DNA' region. We evaluated the distribution of SCCmec types in CoNS from patients attending the Hospital de Clínicas de Porto Alegre over the period August 2004-December 2005. Among the 129 bloodstream isolates, 36 (27.9 %) harboured SCCmec type I, 4 (3.0 %) harboured SCCmec type II, 67 (52 %) harboured SCCmec type III, 1 (0.8 %) harboured SCCmec type IV and 4 (3.0 %) harboured SCCmec types I and III. Seventeen isolates were not typable. Identification of CoNS at the species level indicated that Staphylococcus epidermidis was the most common species, with 87 isolates, followed by Staphylococcus haemolyticus (15), Staphylococcus hominis (13), Staphylococcus capitis (12) and Staphylococcus sciuri (1). SCCmec type III was the most prevalent among isolates of S. epidermidis (52 %). Among these strains, 30 (23 %) harboured a modified SCCmec type III which contained an additional dcs region in comparison with regular type III. SCCmec type III was also highly prevalent (75 %) among S. capitis isolates. The predominant SCCmec type found among S. haemolyticus isolates was type I. However, all four isolates harbouring SCCmec type II belonged to S. haemolyticus. Our results indicate that SCCmec type III was the most prevalent among the CoNS. Isolates with SCCmec type III were more resistant to non-beta-lactam antimicrobials than isolates harbouring SCCmec types I, II and IV, although the increase in resistance was statistically significant only for clindamycin (P=0.021), rifampicin (P=0.010) and levofloxacin (P=0.005).