Shifting genetic structure of invasive serotype 19A pneumococci in the United States.
J Infect Dis
; 203(10): 1360-8, 2011 May 15.
Article
in En
| MEDLINE
| ID: mdl-21398395
ABSTRACT
BACKGROUND:
Following 7-valent conjugate vaccine introduction in the United States in 2000, invasive serotype (sero19A) pneumococcal disease (IPD) emerged rapidly. Sero19A IPD incidence increased slightly during 2005-2008 (from 2.3 cases to 2.5 cases per 100,000 population), whereas sero19A penicillin resistance (defined as a minimum inhibitor concentration [MIC] ≥2 µg/mL) increased significantly (from 28.7% to 43.7%). To better understand changes, we characterized sero19A isolates recovered during 2004-2008.METHODS:
We performed antimicrobial susceptibility testing on all 2767 sero19A IPD isolates identified through the Centers for Disease Control Active Bacterial Core surveillance during 2004-2008. We genotyped 1804 (96.3%) of 1874 sero19A isolates recovered during 2005-2007 and all 148 year 2008 sero19A isolates from children <5 years of age.RESULTS:
Resistant clonal complex (CC) 320/271(19A) increased from 20.9% (115 of 550) to 32.9% (208 of 633; P < .001) of IPD isolates during 2005-2007, which paralleled increased sero19A penicillin resistance (from 28.7% [163 of 567 isolates] to 39.5% [261 of 661 isolates]; P < .001). Total IPD due to 320/271(19A) increased during 2005-2007 and increased from 2.1 to 3.6 cases per 100,000 population during 2005-2008 in children <5 years of age. The penicillin-susceptible/intermediate, putative vaccine-escape CC695(19A) increased from 7.5% (41 of 550) to 13.6% (85 of 633) of sero19A isolates during 2005-2007 (P = .002).CONCLUSIONS:
Sero19A rates may have plateaued; however, clonal shifts are increasing resistance. Increased IPD caused by CC320/271(19A) and CC695(19A) could reflect additional selective advantages in addition to resistance.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pneumococcal Infections
/
Streptococcus pneumoniae
Type of study:
Prognostic_studies
/
Screening_studies
Limits:
Adolescent
/
Adult
/
Aged
/
Aged80
/
Child
/
Child, preschool
/
Humans
/
Infant
/
Middle aged
Country/Region as subject:
America do norte
Language:
En
Journal:
J Infect Dis
Year:
2011
Document type:
Article
Affiliation country:
Estados Unidos