Gram Positive Rods

Bacillus cereus: Morphology, Disease, Biochemical Tests

Bacillus cereus: Morphology, Disease, Biochemical Tests

Bacillus is a gram-positive rods. It produces two enterotoxins, emetic (vomiting) and diarrheal – causing two types of illness.

Actinomyces: Properties, Disease, Lab Diagnosis

Actinomyces: Properties, Disease, Lab Diagnosis

Actinomyces is a heterogeneous group of gram-positive, pleomorphic bacilli responsible for the disease actinomycosis.

Corynebacterium diphtheriae: Pathogenesis, Lab Diagnosis

Corynebacterium diphtheriae: Pathogenesis, Lab Diagnosis

Gram positive club shaped (chinese letter form) bacteria responsible for diphtheria.

Clostridium perfringens: Properties, Diseases, Diagnosis

Clostridium perfringens: Properties, Diseases, Diagnosis

Commensal in the large intestine of humans and is responsible for the disease, gas gangrene.

Clostridium tetani: Properties, Pathogenesis, Lab Diagnosis

Clostridium tetani: Properties, Pathogenesis, Lab Diagnosis

Gram positive, obligate anaerobe, looks like drum-stick shaped and causes tetanus.

Clostridium botulinum: Properties, Pathogenesis, Lab Diagnosis

Clostridium botulinum: Properties, Pathogenesis, Lab Diagnosis

Gram positive, anaerobic rod which produces powerful neurotoxin "botulinum toxin".

Bacillus anthracis: Properties, Pathogenesis, Lab Diagnosis

Bacillus anthracis: Properties, Pathogenesis, Lab Diagnosis

A potential biological weapon which causes important zoonotic disease called anthrax.

Toxins of Clostridium perfringens and their roles

Toxins of Clostridium perfringens and their roles

Alpha (α) toxin, Beta (β) toxin, Epsilon (ε) toxin, and Iota (ι) toxin are the major toxins of Clostridium perfringens.

Gram-Positive Bacilli (Rods) and Diseases

Gram-Positive Bacilli (Rods) and Diseases

Gram-positive bacilli are a diverse group of bacteria responsible for variety of infections such as gas-gangrene, tetanus, anthrax, etc.

Clostridioides difficile: Characteristics, Disease, Lab Diagnosis

Clostridioides difficile: Characteristics, Disease, Lab Diagnosis

Gram positive obligate anaerobe responsible for a unique colonic disease, pseudomembranous colitis.

Elek Test: Principle, Procedure, Results

Elek Test: Principle, Procedure, Results

Elek test is an in vitro immunoprecipitation test to determine whether or not a strain of Corynebacterium diphtheriae is toxigenic.

Endospore Staining: Principle, Procedure, Results

Endospore Staining: Principle, Procedure, Results

In Schaeffer-Fulton`s method, primary stain-malachite green is forced into the spore by steaming the smear, safranin is counterstain.

Shapes of Bacteria: Cocci, Bacilli, and Spirochetes

Shapes of Bacteria: Cocci, Bacilli, and Spirochetes

Bacteria exist in four basic morphologies: cocci; rod-shaped cells, or bacilli; spiral-shaped cells, or spirilla; and comma-shaped cells, or vibrios.

Bacterial Spores: Structure and Spore-Forming Bacteria

Bacterial Spores: Structure and Spore-Forming Bacteria

Bacterial spores are highly resistant, dormant structures formed in response to adverse environmental conditions