Antibiotic-Resistant Streptococcus pneumoniae

A computer-generated image of Streptococcus pneumoniae, based on scanning electron microscope images. CDC.

Key points

• Some Streptococcus pneumoniae (pneumococcus) bacteria resist one or more antibiotics.
• Resistance can make treatment fail.
• Vaccination helps prevent resistant pneumococcal infections.

How common it is

It varies across the United States. Today, pneumococci not susceptible to at least one antibiotic cause about 2 in 5 infections. New vaccines will be critical to cut the rest of this burden.

• CDC's report Antibiotic Resistance Threats in the United States, 2019 rates antibiotic-resistant S. pneumoniae a serious threat, with the latest national estimates of deaths and infections (report).
• CDC's Bact Facts Interactive dashboard shows, year by year, how much invasive pneumococcal disease (IPD) resists selected antibiotics.

What vaccines did

Pneumococcal vaccines protect against specific serotypes (strains). Pneumococcal conjugate vaccines (PCVs) cover the serotypes behind most resistant IPD, and their introduction brought a significant drop in resistant disease. Resistant cases also fell sharply after the definition of penicillin resistance changed in 2008.

CDC's PCV recommendations:

IPD from vaccine serotypes — most of them resistant — has fallen 90% in children and 60% in adults.

The serotype story:

• Before 2000: seven serotypes caused most resistant IPD — 6A, 6B, 9V, 14, 19A, 19F and 23F.
• 2000–2009: PCV7 covered six of them (not 19A). Disease from those six fell; overall and resistant IPD from 19A rose.
• 2010–2019: PCV13, which includes 19A, cut 19A disease sharply. No new serotype took its place as the main cause of resistant IPD in the U.S.
• 2020 to now: the effect of PCV15, PCV20 and PCV21 on resistant infections is not yet known.

CDC uses national surveillance data to estimate IPD cases, resistant ones included, each year.

Who is at risk

• people who recently took antibiotics;
• people who attend or work at childcare centers;
• people who have been hospitalized;
• people with weakened immune systems.

State and local health departments have reported outbreaks in long-term care settings and childcare centers.

Why resistance costs more

• more expensive antibiotics;
• developing new antibiotics;
• surveillance to track resistance;
• repeat illness when treatment fails;
• education for patients, clinicians and microbiologists.

What stands in the way

• unnecessary antibiotic use;
• labs not all using the standard methods (CLSI guidelines) to identify and define resistance;
• the spread of resistant serotypes;
• no vaccine against all serotypes.

What can help

Using antibiotics appropriately and expanding pneumococcal vaccination may slow or reverse resistance — and wider use of recommended vaccines could prevent more infections.

More: Active Bacterial Core surveillance reports · National Notifiable Diseases Surveillance System · Be Antibiotics Aware toolkit · Antimicrobial resistance

Sources

Based on "Antibiotic-resistant Streptococcus pneumoniae," Centers for Disease Control and Prevention; a work of the United States government in the public domain.