Part 2 Bacteriology Quiz Gram Positive Rods

III. Bacillus and Other GPR - LARGE GREY FLAT IRREGULAR COLONIES, RHIZOID OR MEDUSA'S HEAD

Bacterial Species Other names Important Characteristics Lab Identification Types of Infections & Clinical significance
Bacillus anthracis Anthrax in soil, enters via food, wound or inhalation (Woolsorter's disease) Pen sensitive

GPR, long chains, very
rectangular cells, colonies large dry, rhizoid or medusa head

Terrorism
Easily treated with Pen

Anthrax - inhalation, wound (cutaneous) and GI

Bacillus cereus   Creates two types of intoxication; diarrheal & emetic Pen resistant  food intoxication & rarely wound (trauma to eye or heart)

IV. Listeria, Corynebacterium, Erysipelothrix & Lactobacillus

Bacterial Species Other names Important Characteristics Lab Identification Types of Infections & Clinical significance
Corynebacterium diphtheriae   Carried in Humans; lysogenic; requires antitoxin treatment Palisades & Chinese letters
can't be differentiated from normal flora, non-motile, urease - , catalase +, ferments glucose and maltose
Use selective media : Cysteine-tellurite blood agar & Tinsdale's
Diphtheria - pseudomembrane
Listeria monocytogenes   Found in the environment, food pathogen, associated with Short chains GPR; small colonies, catalase +, esculin +, beta hemolytic
hippurate positive
Gastrointestinal to blood to meninges (stillbirths)
Erysipelothrix rhusiopathiae   Carried by animals short rods and long filaments

non-motile catalase -, H2S +

Puncture wound associated with animal contact to septicemia
Lactobacillus spp.   GPR pleomorphic catalase -, nonspore forming GPR  
Gardnerella vaginalis Haemophilus vaginalis   coccobacilli; clue cells; grows on CAP, CNA but not BAP Bacterial vaginosis

V. Branching and Partial AFB GPR - difficult to isolate and identify

Bacterial Species Other names Important Characteristics Lab Identification Types of Infections & Clinical significance
Nocardia asteroides (80% of Nocardia infections) LONG GROWTH PERIODS GPR beaded, branched and filamentous; hyphal-like elements; ubiquitous in the environment direct examination p359
mycolic acid in cell wall
catalase +, strict aerobes, filamentous and branching, hyphal -like
Mostly immunocompromised patients

Traumatic wound or inhalation

Some are intracellular parasites

Streptomyces   non-AFB   Wounds
Actinomycetes   non-AFB; branching presence of granules in the specimen Wounds

 

Return to PAL home page