[Molecular epidemiology of a streptococcus pyogenes related nosocomial outbreak in a burn unit].
BACKGROUND
Group A Streptococcal (GAS) infections have increased in frequency and severity worldwide. During April 1996, a nosocomial outbreak associated to GAS infections affected seven patients admitted to a pediatric burn unit. The causative organism was likely disseminated from the source patient to another child in the emergency room before he was transferred to the burn unit. Patients developed burn infections or invasive disease. One of them died due to a toxic shock syndrome and 3 other lost their skin grafts. Perineal and nasal microbiological surveillance of 42 related health care workers identified only one of them as carrier of S pyogenes.


OBJECTIVE
To report a molecular analysis of an apparently clonal outbreak.


METHODS
The available isolates were analyzed by molecular methods including random amplified polymorphic DNA analysis (RAPD) with 4 different primers, Sma-I pulsed field gel electrophoresis (PFGE) analysis, and speA, speB and speC detection by polymerase chain reaction (PCR).


RESULTS
Two phylogenetically distant and sequentially isolated bacterial groups were identified either by RAPD analysis with selected primers or by Smal-PFGE analysis. The first group involved isolates identified in two patients that included the lethal case. The second bacterial group comprised 5 clinical isolates and the perineal and nasal isolates obtained from a health care worker. Only strains belonging to the first group harbored the speA gene and were associated with invasive disease. The second group could be split further in two subgroups according to their speB profile.


CONCLUSIONS
RAPD analysis with selected primers can reproduce the PFGE-discriminating ability on the epidemiological analysis of GAS infections.
Fica
Alberto
A
Departamento de Medicina, Hospital Clínico Universidad de Chile, Av. Santos Dumont 999, Independencia, Santiago. afica@ns.hospital.uchile.cl
Fernández
Jorge
J
Ebensperger
Germán
G
Cona
Erna
E
Galanti
Andrea
A
Alonso
Catalina
C
Ulloa
María Teresa
MT
Frola
Ana María
AM
Prat
Soledad
S
D002053:Burn Units; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002677:Chile / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology*; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D019105:Random Amplified Polymorphic DNA Technique; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D014774:Virulence
Epidemiología molecular de un brote de infecciones por streptococcus pyogenes en una unidad de quemados.