Spatial exploration of Streptococcus pneumoniae clonal clustering in São Paulo, Brazil.
OBJECTIVE
To examine the spatial distribution of Streptococcus pneumoniae and its clonal patterns collected between 2002 and 2006 in São Paulo, Brazil.


METHODS
As part of an observational study in São Paulo city, Brazil, S. pneumoniae isolates routinely cultured from blood, respiratory specimens, or cerebrospinal and other profound fluids were selected. Additionally, only isolates with either penicillin (PEN) intermediate (I) or resistant (R) status on routine antibiogram were included, in order to obtain a higher probability of clonal isolates. A single I/R S. pneumoniae isolate per patient was included and submitted to genotypic determination by pulsed field gel electrophoresis (PFGE). Minimum inhibitory concentrations (MICs) were determined for the isolates by Etest® to PEN and other antimicrobials. Each isolate was geocoded in a digital map. The Kernel function and ratio methods between total isolates vs. clones were used in order to explore possible cluster formations.


RESULTS
Seventy-eight (78) S. pneumoniae community isolates from two major outpatient centers in São Paulo, Brazil, were selected from the databank according to their penicillin susceptibility profile, i.e. R or I to penicillin assessed by oxacillin disc diffusion. Of these, 69 were submitted to PFGE, 65 to MIC determination, and 48 to spatial analytical procedures. Preliminary spatial analysis method showed two possible cluster formation located in southwest and southeast regions of the city.


CONCLUSIONS
Further analyses are required for precisely determining the existence of S. pneumoniae clusters and their related risk factors. Apparently there is a specific transmission pattern of S. pneumoniae clones within certain regions and populations. GIS and spatial methods can be applied to better understand epidemiological patterns and to identify target areas for public health interventions.
Special Laboratory of Clinical Microbiology, Universidade Federal de São Paulo, SP, Brazil.
Amilton
A
Mouro
Carlos
C
Kiffer
Paula C M
PC
Koga
Antonio M V
AM
Monteiro
Eduardo Celso Gerbi
EC
Camargo
Antonio Carlos Campos
AC
Pignatari
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D040362:Geographic Information Systems; D006801:Humans; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance / Q000235:genetics*; D010406:Penicillins / Q000494:pharmacology*; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics*
D000900:Anti-Bacterial Agents; D010406:Penicillins