Drug Resistance

Some Streptococcus pneumoniae (pneumococcus) are resistant to one or more antibiotics. Resistance can lead to treatment failures.

Latest data

CDC’s Antibiotic Resistance Threats in the United States, 2019 includes the latest national death and infection estimates that underscore the continued threat of antibiotic resistance. The report identifies drug-resistant S. pneumoniae as a serious threat.

View the Streptococcus pneumoniae reportpdf icon.

Background

Until 2000, pneumococcal infections caused 60,000 cases of invasive disease each year. According to Active Bacterial Core surveillance (ABCs) data, up to 40% of these infections were caused by pneumococcal bacteria that were resistant to at least one antibiotic. These numbers have decreased greatly following:

  • The introduction of pneumococcal conjugate vaccines for children
  • A change in definition of non-susceptibility (resistance) to penicillin in 2008

In 2019, ABCs estimatedpdf icon there were about 30,300 cases of invasive pneumococcal disease. Available data show that pneumococcal bacteria are resistant to one or more antibiotics in more than 30% of cases. How common drug-resistant Streptococcus pneumoniae (DRSP) is varies throughout the United States.

State and local health departments have reported outbreaks of DRSP in

  • Long-term care settings
  • Institutions for people living with HIV
  • Childcare centers

Trends

Prior to 2000, seven serotypes (6A, 6B, 9V, 14, 19A, 19F, and 23F) accounted for most DRSP in the United States. In 2000, CDC began recommending 7-valent pneumococcal conjugate vaccine (PCV7) for all U.S. children. PCV7 protected against most of the serotypes that caused DRSP at the time but not 19A. After PCV7 introduction, serotype 19A emerged to cause most DRSP. The United States began using 13-valent pneumococcal conjugate vaccine (PCV13), which protects against 19A, in 2010. Since then, rates of disease caused by serotype 19A have greatly decreased.

Both PCV7 and PCV13 prevented many infections due to drug-resistant pneumococcal serotypes.

In 2022, CDC began recommending a 15-valent or 20-valent pneumococcal conjugate vaccine for all adults aged 65 years and older and adults at increased risk for pneumococcal disease. The impact these higher valency vaccines will have on drug-resistant pneumococcal serotypes is yet to be determined.

Costs

DRSP is associated with increased costs compared to infections caused by non-resistant (susceptible) pneumococcus. This is because of

  • The need for more expensive antibiotics, new antibiotic drug development, and for surveillance to track resistance patterns
  • Repeat disease due to treatment failures
  • Educational requirements for patients, clinicians, and microbiologists

Risk Groups

People who attend or work at childcare centers are at increased risk for infection with DRSP. People with pneumococcal infections who recently used antibiotics are more likely to have a resistant infection than those who have not.

Surveillance

CDC funds ABCs, an active, population-based surveillance system in 10 states. All types of invasive pneumococcal disease (including DRSP) are included in the national public health surveillance system, National Notifiable Diseases Surveillance System (NNDSS). These surveillance data are used to estimate how many cases of invasive pneumococcal disease (including DRSP) occur each year in the United States.

Several private-sector systems also track DRSP.

Prevention: Challenges and Opportunities

There are several factors that create challenges for preventing emerging drug resistance of pneumococcus, including

  • Widespread overuse of antibiotics
  • Spread of resistant serotypes
  • Underuse of recommended vaccines for adults with indications
  • Lack of adoption by some clinical laboratories of standard methods (NCCLS guidelines) for identifying and defining DRSP
  • Lack of vaccine availability to protect against all serotypes of pneumococcus

Improving judicious use of antibiotics and expanding use of vaccines may slow or reverse emerging drug resistance. Prevention of infections could improve through expanded use of recommended vaccines (PCV13, PCV15, PCV20, PPSV23).