Epidemiology of invasive pneumococcal disease in BC during the introduction of conjugated pneumococcal vaccine.
OBJECTIVE
Antimicrobial resistance in Streptococcus pneumoniae has increased in recent decades. We linked two surveillance programs to evaluate trends in incidence, serotype distribution, and antimicrobial resistance in invasive pneumococcal disease (IPD) since the heptavalent pneumococcal conjugate vaccine (PCV7) was introduced in BC in 2003.


METHODS
IPD case reports for BC from 2002-2005 from the BC Centre for Disease Control were linked to serotype and antimicrobial susceptibility results from the National Centre for Streptococcus (NCS).


RESULTS
There was a significant decrease in IPD incidence in children <5 from 54/100,000 in 2002 to 16/100,000 population in 2005 (70% decrease, p < 0.001). The most dramatic decline was in children aged 1 year, where the rate fell from 135/100,000 to 15/100,000 (89% decrease, p for trend <0.001). Overall, 728/1288 (56.5%) reported cases of IPD were referred to NCS. For all matched cases, the proportion of isolates of PCV7 preventable serotypes decreased from 68.9% to 43.8% (p for trend <0.001) between 2002 and 2005. In children <2 years, this proportion decreased from 83.0% (39/47 cases) to 16.7% (1/6 cases) (p = 0.006). The prevalence of non-susceptible isolates was highest for trimethoprim-sulfamethoxazole (15.3%, 111/725 tested), penicillin (9.1%, 66/728), and erythromycin (9.1%, 66/727). 10.3% (75/728) were non-susceptible to > or =2 classes of antimicrobials. Children <15 years of age had the highest proportion of non-susceptible isolates.


CONCLUSIONS
The incidence of IPD in children has decreased significantly since the introduction of PCV7. Comprehensive serotype and antimicrobial susceptibility can aid in evaluating the impact of immunization programs.
Winters
Meghan
M
Department of Health Care and Epidemiology, University of British Columbia, Vancouver, BC. mwinters@interchange.ubc.ca
Patrick
David M
DM
Marra
Fawziah
F
Buxton
Jane
J
Chong
Mei
M
Isaac-Renton
Judith L
JL
Shaw
Carol
C
Tyrrell
Gregory J
GJ
Lovgren
Marguerite
M
Paulus
Stephane
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D001955:British Columbia / Q000453:epidemiology; D016022:Case-Control Studies; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000627:therapeutic use; D005260:Female; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000627:therapeutic use; D011008:Pneumococcal Infections / Q000188:drug therapy* / Q000453:epidemiology* / Q000503:physiopathology / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D011159:Population Surveillance; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use
D010406:Penicillins; D022242:Pneumococcal Vaccines; D004917:Erythromycin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination