Early microbial colonization of cystic fibrosis patients identified by neonatal screening, with emphasis on Staphylococcus aureus.
OBJECTIVE
To assess bacterial colonization prospectively in patients with cystic fibrosis identified by neonatal screening. To assess susceptibility to antimicrobials and to perform the molecular typing of Staphylococcus aureus strains isolated from the oropharynx of patients during the study.


METHODS
Twenty-five cystic fibrosis patients receiving regular treatment at the Cystic Fibrosis Outpatient Clinic of Hospital de Clínicas of Universidade Federal do Paraná, Brazil, were included in the study. All patients were identified by trypsin-like immunoreactivity and their diagnosis was confirmed by two or more sweat tests. Oropharyngeal swabs were collected and cultured according to routine methods; bacterial colonies were phenotypically identified and their susceptibility to antimicrobials was tested. S. aureus isolates were submitted to molecular typing using pulsed-field gel electrophoresis.


RESULTS
Out of 234 oropharyngeal swabs, S. aureus was the most frequently isolated strain (76% of patients, 42% of swabs), followed by Pseudomonas aeruginosa (36% of patients, 16% of swabs) and Haemophilus spp. (76% of patients; 19% of swabs). Seventy-three isolates were obtained from 19 patients colonized with S. aureus, of which 18 were oxacillin-resistant (24.6%), isolated from two patients, with the same electrophoretic profiles as that of the Brazilian clone. The remaining oxacillin-sensitive isolates were distributed into 18 electrophoretic profiles.


CONCLUSIONS
There was higher prevalence of S. aureus, with earlier isolation than other pathogens. Multi-sensitive isolates were distributed into different clones, characterizing non-transmissibility among community-acquired strains. The isolated oxacillin-resistant S. aureus showed identical electrophoretic profiles, probably acquired in hospital. P. aeruginosa was not so frequent in the studied population.
Souza
Helena A P H M
HA
Universidade Federal do Paraná (UFPR), Curitiba, PR. helenahms@onda.com.br
Nogueira
Keite S
KS
Matos
Adriana P
AP
Vieira
Ricardo P
RP
Riedi
Carlos A
CA
Rosário
Nelson A
NA
Telles
Flávio Q
FQ
Costa
Libera M Dalla
LM
D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015373:Bacterial Typing Techniques; D001938:Brazil / Q000453:epidemiology; D015169:Colony Count, Microbial; D003550:Cystic Fibrosis / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016106:Methicillin Resistance / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015997:Neonatal Screening; D010068:Oxacillin / Q000627:therapeutic use*; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology* / Q000635:transmission; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D010068:Oxacillin