Streptococcus pneumoniae Invasive Disease, 2010

Statewide active surveillance for invasive Streptococcus pneumoniae (pneumococcal) disease began in 2002, expanded from the metropolitan area, where active surveillance was ongoing since 1995. In 2010, 649 (12.3 per 100,000) cases of invasive pneumococcal disease were reported. By age group, annual incidence rates per 100,000 were 23.9 cases among children aged 0-4 years, 3.4 cases among children and adults aged 5-39 years, 13.6 cases among adults 40-64 years, and 35.3 cases among adults aged 65 years and older.

In 2010, pneumonia accounted for 403 (62%) cases of invasive pneumococcal disease among all cases (i.e., those infections accompanied by bacteremia or isolation of pneumococci from another sterile site such as pleural fluid). Bacteremia without another focus of infection accounted for 168 (26%) cases statewide. Pneumococcal meningitis accounted for 38 (6%) cases. Sixty-three (10%) patients with invasive pneumococcal disease died. Health histories were available for 48 (76%) of the 63 cases who died. Of these, 46 had an underlying health condition reported. The conditions most frequently reported were chronic obstructive pulmonary disease (11), smoker (10), atherosclerotic cardiovascular disease (9), heart failure (9), and diabetes (7). In 1999, the year before the pediatric pneumococcal conjugate vaccine (Prevnar [PCV-7]) was licensed, the rate of invasive pneumococcal disease among children < 5 years in the metropolitan area was 111.7 cases per 100,000. Over the years 2000 through 2002 there was a major downward trend in incidence in this age group (Figure 5). Rates in each of the subsequent 8 years were somewhat higher, although there has not been a continuing upward trend (Figure 5). Based on the distribution of serotypes among isolates from these cases, this increase was limited to disease caused by non-vaccine serotypes (i.e. serotypes other than the seven included in PCV-7) (Figure 5). This small degree of replacement disease due to non-PCV-7 serotypes, similar to that seen in other parts of the country, has been far outweighed by the declines in disease caused by PCV-7 serotypes.

In March 2010, the FDA approved a new 13-valent pediatric pneumococcal conjugate vaccine (PCV-13 [Prevnar 13]) which replaces PCV-7. The new vaccine provides protection against the same serotypes in PCV-7, plus 6 additional serotypes (serotypes 1, 3, 5, 6A, 7F, and 19A). Since 2007, the majority of invasive pneumococcal disease cases among children under 5 years of age have been caused by the 6 additional serotypes included in PCV-13 (Figure 5). In 2010, 40% of cases occurring among Minnesotans of all ages were caused by 3 of the new PCV-13-included serotypes: 7F (17%), 19A (16%), and 3 (8%).
Of the 625 isolates submitted from 2010 cases, 146 (23%) isolates were resistant to penicillin using meningitis breakpoints. Using non-meningitis breakpoints, 4 (1%) of 625 isolates were resistant to penicillin and 56 (9%) exhibited intermediate level resistance (Note: CLSI penicillin breakpoints changed in 2008; refer to the MDH Antibiogram on pages 28-29 for details). Multi-drug resistance (i.e., high-level resistance to two or more antibiotic classes) was exhibited in 125 (20%) isolates.

Figure 4. Invasive Pneumococcal Disease Incidence Among Children <5 and Adults >65 years of Age, by Year and Serotype, Twin Cities Metropolitan Area, 1999-2008

Updated Monday, 28-Nov-2011 14:10:34 CST