# Middlebrook 7H10 Agar

> growth medium used to culture Mycobacterium species

**Wikidata**: [Q6391649](https://www.wikidata.org/wiki/Q6391649)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Middlebrook_7H10_Agar)  
**Source**: https://4ort.xyz/entity/middlebrook-7h10-agar

## Summary
Middlebrook 7H10 Agar is a specialized growth medium formulated to culture Mycobacterium species, the bacteria responsible for tuberculosis and related infections. It is a solid agar-based variant of the Middlebrook series that provides the nutrients and conditions these slow-growing organisms require for laboratory isolation and study.

## Key Facts
- **Instance of**: growth medium (Wikidata classification)
- **Primary use**: selective culture of Mycobacterium spp.
- **Language coverage**: Wikipedia articles available in Arabic, English, Japanese, Polish, and Thai
- **Wikidata sitelinks**: 5 across all language editions
- **Freebase ID**: /m/0bhb4ww
- **Discontinued Microsoft Academic ID**: 2780816980
- **Arabic alias**: آغار مدلبروك ٧H١٠

## FAQs
### Q: What organism is Middlebrook 7H10 Agar designed to grow?
A: It is formulated specifically for Mycobacterium species, including the slow-growing M. tuberculosis complex and non-tuberculous mycobacteria.

### Q: Is Middlebrook 7H10 Agar a liquid or solid medium?
A: It is an agar-based solid medium, making colony morphology visible and allowing isolation of pure cultures.

### Q: How does 7H10 differ from other Middlebrook formulations?
A: 7H10 is the agar version; Middlebrook 7H9 is the corresponding broth. Both share the same basal nutrients but differ in physical state.

### Q: Why is a special medium needed for mycobacteria?
A: Mycobacteria grow extremely slowly (weeks rather than days) and have a lipid-rich cell wall that impedes uptake of standard nutrients; Middlebrook media supply fatty acids, albumin, catalase, and dextrose to overcome these limitations.

## Why It Matters
Middlebrook 7H10 Agar is a cornerstone medium in clinical and research mycobacteriology. Because Mycobacterium tuberculosis can take 3–8 weeks to form visible colonies, the medium must sustain slow metabolism without overgrowth by faster contaminants. The transparent agar allows microscopic inspection of colony morphology early in incubation, aiding presumptive identification. Its selectivity, achieved by added antibiotics in clinical formulations, suppresses normal flora in sputum specimens, increasing the chance of detecting low numbers of acid-fast bacilli. Consequently, 7H10 plates are still referenced in global tuberculosis guidelines as a gold-standard solid medium, even as rapid molecular tests proliferate. For researchers, the defined nutrient composition supports biochemical assays, drug-susceptibility testing, and genetic manipulation protocols that underpin new diagnostics and therapeutics against one of humanity’s oldest pathogens.

## Notable For
- **First transparent agar for mycobacteria** – colonial morphology visible without disturbing the plate
- **Widely cited in WHO and CDC tuberculosis laboratory manuals** as the reference solid medium
- **Compatible with antibiotic supplementation** (e.g., PANTA) for direct specimen inoculation
- **Stable long incubation** – resists dehydration during the 6–8-week observation period required for slow growers

## Body
### Formulation and Physical Properties
Middlebrook 7H10 Agar is prepared from a base of inorganic salts, vitamins, and a high concentration of glycerol. The key enrichment is Middlebrook OADC (Oleic Acid–Albumin–Dextrose–Catalase) supplement added after sterilization. The final gel is clear and colorless, allowing transmitted-light examination of micro-colonies as early as one week.

### Intended Use
Primary isolation of Mycobacterium spp. from decontaminated clinical specimens (sputum, tissue, sterile body fluids) and sub-culturing of reference strains for drug-susceptibility testing.

### Incubation Conditions
Standard protocol specifies 5–10 % CO₂, 35–37 °C, sealed or humidified environment to prevent desiccation during the extended incubation period.

### Interpretation
Visible colonies appear after 7–21 days for rapid growers and up to 8 weeks for M. tuberculosis complex. Typical M. tuberculosis colonies are rough, non-pigmented, and buff-colored.

### Storage and Shelf Life
Prepared plates are stored at 2–8 °C and generally used within one month; commercial variants containing antibiotics have shorter expiration dates once supplemented.