Can a patient be a carrier of Group A Streptococcus (GAS) without a previous diagnosis of strep?

Group A Streptococcal Carriers Without Prior Diagnosis

Yes, patients can be carriers of Group A Streptococcus (GAS) without ever having been diagnosed with strep throat in the past. 1

Understanding GAS Carriers

• During winter and spring in temperate climates, up to 20% of asymptomatic school-aged children may be GAS carriers without any history of diagnosed streptococcal infection 1
• Carriers have GAS present in their pharynx but show no evidence of an active immunologic response to the organism, such as rising anti-streptococcal antibody titers 1
• These individuals may be colonized by GAS for 6 months or longer without ever developing symptoms or being diagnosed with strep throat 1

Characteristics of GAS Carriers

• Carriers are unlikely to spread the organism to their close contacts 1
• They are at very low risk, if any, for developing suppurative complications (like peritonsillar abscess) or nonsuppurative complications (like acute rheumatic fever) 1
• Carriers may experience episodes of intercurrent viral pharyngitis that can be mistaken for streptococcal pharyngitis when testing reveals GAS in the throat 1

Distinguishing Carriers from Acute Infection

• In practice, it is difficult to differentiate a carrier with an intercurrent non-GAS infection from a patient with acute streptococcal pharyngitis 1
• Helpful clues to distinguish carriers from true infections include:
  • Patient's age (school-aged children have higher carrier rates) 1
  • Season of the year (higher carrier rates in winter/spring) 1
  • Local epidemiology (presence of influenza or enteroviral illnesses) 1
  • Precise nature of presenting symptoms 1
• Serological testing can help distinguish carriers from true infections, though this is not routinely performed in clinical practice 1, 2

Clinical Implications

• Streptococcal carriers do not ordinarily require antimicrobial therapy 1
• Testing asymptomatic individuals for GAS is not recommended as it may lead to unnecessary antibiotic use 3, 4
• The Infectious Diseases Society of America recommends against testing asymptomatic household contacts of patients with GAS pharyngitis 3
• It is more difficult to eradicate GAS from the upper respiratory tracts of carriers compared to those with acute infections 1

Special Considerations

• In rare cases, eradication of the carrier state may be warranted, such as:
  • When "Ping-Pong" spread of GAS has been occurring within a family 1
  • In healthcare workers who have been linked to nosocomial outbreaks 5
  • In communities with outbreaks of acute rheumatic fever or post-streptococcal glomerulonephritis 1

Common Pitfalls

• Treating carriers with intercurrent viral infections with antibiotics leads to unnecessary antibiotic use 3, 4
• Failing to recognize that a positive strep test in a patient with viral symptoms may represent carriage rather than acute infection 1
• Performing follow-up throat cultures after treatment in asymptomatic patients is not recommended in most cases 1