Selective culture media · Founded 2024–2025

A selective agar built from a kitchen spice, not antibiotics or dyes.

CultureClove is turning a published laboratory medium into a ready-to-pour plate: Mueller Hinton Agar enriched with 15% v/v clove water extract. Gram-negative bacteria grow on it, while the Gram-positive pathogens tested did not.

See the solutionView the results
15% v/vclove water extract in the agar (MHA-C15)
4Gram-negative species that grew on it
0Gram-positive growth on MHA-C15 in the study
Medium profile At a glance
Base agarMueller Hinton Agar
MHA
Selective agentWater extract of clove
15% v/v
IncubationStandard aerobic culture
37 °C · 24 h
Why it matters: Selectivity comes from one natural extract, with no antibiotic or dye added to the plate.
The problem

Mixed samples hide the bacteria you need to find

Clinical and environmental samples often contain Gram-positive and Gram-negative bacteria together. Separating them is the first step of many workflows.

Overgrowth slows isolation

When Gram-positive organisms share the plate, Gram-negative colonies are harder to pick and identify.

Selectivity usually means additives

Common selective media rely on chemical agents such as dyes or bile salts to suppress unwanted growth.

Phenotype must stay intact

A useful selective medium should not change how the isolates stain or respond to antibiotics later.

Our solution

One extract, a clear dividing line

The research team found that clove water extract, added to Mueller Hinton Agar at the right level, separates the two groups. CultureClove is building that formula into a standardised product.

Selectivity

Gram-positives held back

0Gram-positive counts on MHA-C15
  • S. aureus, S. epidermidis, S. pneumoniae and S. pyogenes tested
  • E. faecalis, B. subtilis and S. mutans also tested
  • None of the major Gram-positive pathogens tested grew
Recovery

Gram-negatives still grow

4Gram-negative species recovered
  • E. coli and K. pneumoniae
  • P. aeruginosa and S. typhimurium
  • P. aeruginosa grew best in the study
Integrity

Isolates stay comparable

SameGram stain and disk-diffusion results vs plain MHA
  • Gram staining unchanged after growth on MHA-C15
  • Antibiotic sensitivity profile unchanged
  • Supports use before downstream testing
How it works

How the medium is made

The method follows the published protocol step by step.

  1. 1

    Extract the clove

    Clove powder at 20% w/v is stirred in hot distilled water at 50 °C for 30 min, then filtered.

    20% w/v50 °C30 min
  2. 2

    Blend into agar

    The extract is added to Mueller Hinton Agar to give 15% v/v, the level the study named MHA-C15.

    MHA15% v/v
  3. 3

    Plate the sample

    Strains or samples are streaked onto the plate and incubated under standard conditions.

    37 °C24 h
  4. 4

    Read and pick

    Gram-negative colonies grow while the Gram-positive pathogens tested do not, so colonies can be taken forward for identification.

    Gram stainDisk diffusion
Results

What the laboratory study showed

In vitro testing on reference bacterial strains, with colony counts from three independent experiments.

15%lowest extract level that separated the two groups
5% and 10%levels where both groups still grew
25%level that inhibited both groups
11bacterial species tested in total
Growth by extract level (as reported)
MediumGram-positiveGram-negative
MHA-C5 and MHA-C10GrowthGrowth
MHA-C15No growthGrowth
MHA-C25InhibitedInhibited

Source: Al-Blooshi et al., BMC Research Notes 14, 211 (2021). doi:10.1186/s13104-021-05628-2

Who it's for

Who it is for

Labs that routinely need to pull Gram-negative organisms out of mixed growth.

Clinical microbiology labs

  • Primary isolation of Gram-negative pathogens
  • A simple plate format for routine use
  • Isolates ready for stain and sensitivity testing

Teaching laboratories

  • Shows selective media with a familiar ingredient
  • Low-hazard preparation
  • Clear visual contrast between groups

Media manufacturers

  • A natural selective agent to license
  • Defined preparation method
  • Room for further formulation work
Where we are

Where the evidence stands

We are clear about what has and has not been shown.

Laboratory strains only

The study tested a limited number of pathogenic species. Performance on real clinical samples has not been reported.

Active compound unknown

The authors suggest eugenol or tannins may be responsible, but the active component has not been identified.

Batch consistency

A natural extract can vary between sources. Standardising each batch is part of our development work.

The team

The team

Founded in 2024–2025 by the research team behind the clove-based selective medium study.

SA

Shooq Yousef Al-Blooshi

Co-author of the CultureClove research.

ML

Mustafa Amir Abdul Latif

Co-author of the CultureClove research.

NS

Nour K. Sabaneh

Co-author of the CultureClove research.

MM

Michael Mgaogao

Co-author of the CultureClove research.

AH

Ashfaque Hossain

Co-author of the CultureClove research.

Frequently asked questions

What is in the medium?

Mueller Hinton Agar with a water extract of clove at 15% v/v. No antibiotics or dyes are added.

Which bacteria grow on it?

In the study, E. coli, K. pneumoniae, P. aeruginosa and S. typhimurium grew on MHA-C15.

Which bacteria are held back?

The Gram-positive species tested, including S. aureus, S. pneumoniae, S. pyogenes, E. faecalis and S. mutans, did not grow.

Does it change the isolates?

Gram staining and disk-diffusion antibiotic sensitivity were unchanged compared with plain Mueller Hinton Agar.

Is it available to buy?

Not yet. The evidence is from laboratory strains, and testing on clinical samples is still needed.

The research

Peer-reviewed science behind CultureClove.

Read the full study behind the product.

Read the paper

Al-Blooshi, S. Y., Latif, M. A. A., Sabaneh, N. K., Mgaogao, M., & Hossain, A. (2021). Development of a novel selective medium for culture of Gram-negative bacteria. BMC Research Notes, 14, 211. https://doi.org/10.1186/s13104-021-05628-2

https://doi.org/10.1186/s13104-021-05628-2