Other catalase-negative Gram-positive cocci
- Bacterium
Gram-positive
Thick peptidoglycan wall: stains purple.- For completeness
Rare relatives of streptococci from the mouth, gut and food that mostly cause endocarditis, bloodstream and urinary infections.
Also called: Abiotrophia and Granulicatella (nutritionally variant streptococci), Aerococcus, Gemella, Leuconostoc, Pediococcus, Lactococcus
Quick facts
- Type
- Bacterium · Streptococci and enterococci
- Gram / shape
- Gram-positive · Cocci in chains
- Spread
- Endogenous from mouth · Leuconostoc
- Causes
- Infective endocarditis · Urinary tract infection
- Treatment
- Endocarditis from Abiotrophia
At a glance
- Gram
- Gram-positive
- Shape
- Cocci in chains, pairs, clusters or tetrads, depending on the genus
- Oxygen
- Facultative anaerobes
- Family
- Several families outside Streptococcus (Carnobacteriaceae, Aerococcaceae and others)
Morphology
- Abiotrophia and Granulicatella grow only with pyridoxal and L-cysteine, or as satellites around a Staphylococcus aureus streak
- Aerococcus: catalase-negative cocci in pairs and clusters that look like staphylococci on Gram stain; alpha-haemolytic
- Gemella stains weakly and may look Gram-negative
- Leuconostoc and Pediococcus are naturally resistant to vancomycin
Transmission
- Endogenous from mouth, gut or urinary tract flora
- Leuconostoc, Pediococcus and Lactococcus can come from food and dairy products
- Catheters and intravenous lines in hospital patients
Reservoir: Human mouth, gut and genitourinary tract; plants, dairy and fermented foods
Isolation precautions
What the care team adds to standard precautions.
- Standard
Virulence factors
- Low virulence; they need damaged valves, devices or weak defences
- Adhere to heart valves and form vegetations
Diseases it causes
- Infective endocarditis, often culture-negative (Abiotrophia, Granulicatella, Gemella, Aerococcus) Infective endocarditis →
- Urinary tract infection in older men with urological disease (Aerococcus urinae) Urinary tract infection (acute cystitis) →
- Bacteraemia in immunocompromised or catheterised patients (Leuconostoc, Pediococcus, Lactococcus) Sepsis and septic shock →
Clinical picture
- Endocarditis from nutritionally variant streptococci relapses and fails treatment more often than other viridans endocarditis
- Aerococcus urinae: older man with prostate disease, urosepsis and sometimes embolic stroke from endocarditis
Diagnosis
- Tell the laboratory when endocarditis is suspected; supplemented media or satellite tests are needed for Abiotrophia and Granulicatella
- MALDI-TOF mass spectrometry and 16S rRNA sequencing (also on valve tissue)
- A vancomycin-resistant Gram-positive coccus that is not an enterococcus: think Leuconostoc or Pediococcus
Treatment
Endocarditis from Abiotrophia or Granulicatella is treated like enterococcal endocarditis: penicillin, ampicillin or ceftriaxone combined with gentamicin, with vancomycin as an alternative; Aerococcus responds to a beta-lactam, often with an aminoglycoside; Leuconostoc and Pediococcus are treated with penicillin or ampicillin, never vancomycin.
Drug class only; doses and regimens are set by the clinician from the current guideline.
In Pharmacology:
Prevention
- Oral hygiene and dental care in people with valve disease
- Endocarditis prophylaxis for the highest-risk cardiac patients before dental procedures
- Catheter care in immunocompromised patients
Test yourself
Think of the answer, then tap the question to see it.
What is satellitism and which organisms show it?
Growth only near a Staphylococcus aureus streak, which supplies nutrients; seen in Abiotrophia and Granulicatella.
How is endocarditis due to Granulicatella or Abiotrophia usually treated?
Like enterococcal endocarditis: a beta-lactam (penicillin, ampicillin or ceftriaxone) plus gentamicin, or vancomycin.
Which catalase-negative coccus causes urinary infection and endocarditis in older men?
Aerococcus urinae.
Which Gram-positive cocci other than enterococci are naturally resistant to vancomycin?
Leuconostoc and Pediococcus.
Connections
← Back to the group: Streptococci and enterococci
Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Granulicatella infections: Comprehensive review of an elusive opportunistic pathogen (World Journal of Clinical Cases, 2025); Aerococcus urinae Mitral Valve Endocarditis-Related Stroke: A Case Report and Literature Review (Journal of Investigative Medicine High Impact Case Reports, 2018).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.