[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Streptococci and enterococci](https://durgical.com/en/microbiology/groups/streptococci-and-enterococci/) › Other catalase-negative Gram-positive cocci

# 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.

Updated Nov 13, 2026

Also called: Abiotrophia and Granulicatella (nutritionally variant streptococci), Aerococcus, Gemella, Leuconostoc, Pediococcus, Lactococcus

## Quick facts

**Type**
Bacterium · [Streptococci and enterococci](https://durgical.com/en/microbiology/groups/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

On this page

- The basics Key points
- At a glance
- Morphology
- Transmission
- Memory aid
- What the colours mean

- Clinical Virulence factors
- Diseases it causes
- Clinical picture
- Diagnosis

- Treatment Treatment
- Prevention

- Study Test yourself

- Connections Connections

## Key points

- Satellite growth around S. aureus: nutritionally variant streptococci (Abiotrophia, Granulicatella).
- Their endocarditis is treated like enterococcal endocarditis.
- Catalase-negative cocci in clusters in the urine of an older man: Aerococcus urinae.
- Vancomycin-resistant Gram-positive cocci that are not enterococci: Leuconostoc or Pediococcus.

## 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 →](https://durgical.com/en/conditions/infective-endocarditis/)
- Urinary tract infection in older men with urological disease (Aerococcus urinae) [Urinary tract infection (acute cystitis) →](https://durgical.com/en/conditions/urinary-tract-infection/)
- Bacteraemia in immunocompromised or catheterised patients (Leuconostoc, Pediococcus, Lactococcus) [Sepsis and septic shock →](https://durgical.com/en/conditions/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:

- [Benzylpenicillin (penicillin G)](https://durgical.com/en/pharmacology/benzylpenicillin/)
- [Ampicillin](https://durgical.com/en/pharmacology/ampicillin/)
- [Ceftriaxone](https://durgical.com/en/pharmacology/ceftriaxone/)
- [Gentamicin](https://durgical.com/en/pharmacology/gentamicin/)
- [Vancomycin](https://durgical.com/en/pharmacology/vancomycin/)

## 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

## Memory aid

The «picky eaters» (Abiotrophia, Granulicatella) only grow if Staphylococcus shares its food; the «vancomycin rebels» (Leuconostoc, Pediococcus) are born resistant.

## 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.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/other-catalase-negative-gram-positive-cocci/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

## Connections

## Related 4

- [Viridans streptococci](https://durgical.com/en/microbiology/viridans-streptococci/)
- [Enterococcus](https://durgical.com/en/microbiology/enterococcus/)
- [Staphylococcus aureus](https://durgical.com/en/microbiology/staphylococcus-aureus/)
- [HACEK organisms](https://durgical.com/en/microbiology/hacek-organisms/)

## Related conditions 3

- [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/)
- [Urinary tract infection (acute cystitis)](https://durgical.com/en/conditions/urinary-tract-infection/)
- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)

[← Back to the group: Streptococci and enterococci](https://durgical.com/en/microbiology/groups/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](https://www.wjgnet.com/2307-8960/full/v13/i29/110965.htm) (World Journal of Clinical Cases, 2025); [Aerococcus urinae Mitral Valve Endocarditis-Related Stroke: A Case Report and Literature Review](https://pmc.ncbi.nlm.nih.gov/articles/PMC5833211/) (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.

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