Figure - Bacterial Growth Curve

Purpose

Visualize lag → log → stationary → death and when labs/AST “care” about phase.

Used In

• Bacterial Growth Curve
• Antimicrobial Susceptibility Testing
• Learning Media Hub

Diagram

%%{init: {'themeVariables': {'xyChart': {'plotColorPalette': '#2563eb'}}}}%%
xychart-beta
    title "Bacterial Growth Curve (conceptual)"
    x-axis [Lag, Log, Stationary, Death]
    y-axis "Log CFU" 0 --> 10
    line [2, 8, 9, 4]

flowchart LR
  A[Lag<br/>adapt enzymes] --> B[Log / Exponential<br/>constant doubling]
  B --> C[Stationary<br/>growth ≈ death]
  C --> D[Death / Decline<br/>net loss ± persisters]

  B -. preferred .-> AST[AST inoculum]
  C -. stress / spores .-> SP[[Bacterial Endospore]]
  C -. tolerance .-> BF[[Biofilm]]

Teaching Legend

Phase	Physiology	Clinical / lab hook
Lag	Induction, little CFU rise	Fresh inoculum adapting
Log	Fast, uniform growth	Standard AST; many β-lactams need growth
Stationary	Nutrient stress	Persisters; sporulation in some spp.
Death	Net die-off	Old cultures → weird Gram variability

Quick Self-Check

1. Which phase for McFarland inoculum prep?
2. Why might a “susceptible” drug fail against non-growing cells?