Overview of Important Bacterial Pathogens and Their Effects

Rickettsia rickettsii

A Gram-negative bacterium transmitted by ticks, responsible for Rocky Mountain spotted fever. It infects the endothelial cells of blood vessels, causing fever, rash, and potential vascular damage.

Caulobacter

A genus of bacteria known for its unique cell cycle and stalk formation. Found in aquatic environments, it attaches to surfaces and is a model organism for studying cell differentiation.

Rhizobium

Soil bacteria that form symbiotic relationships with leguminous plants. They fix atmospheric nitrogen into ammonia, essential for plant growth, through root nodules.

Neisseria gonorrhoeae

A Gram-negative bacterium that causes gonorrhea, a sexually transmitted infection. It infects the mucous membranes of the reproductive tract, leading to inflammation and discharge.

Bordetella pertussis

The bacterium responsible for whooping cough (pertussis), a highly contagious respiratory disease. It produces toxins that paralyze cilia in the respiratory tract, causing severe coughing.

Thiobacillus

A genus of sulfur-oxidizing bacteria that plays a role in sulfur cycling by oxidizing inorganic sulfur compounds, typically found in soil and aquatic environments.

Escherichia coli

A common Gram-negative bacterium found in the intestines of humans and animals. While most strains are harmless, some can cause food poisoning, urinary tract infections, and other illnesses.

Salmonella typhi

The causative agent of typhoid fever, which spreads through contaminated food or water. It invades the intestinal wall and can cause systemic infection.

Salmonella enteritidis

A bacterium commonly associated with food poisoning, especially from raw or undercooked eggs and poultry, causing gastrointestinal illness.

Klebsiella pneumoniae

A Gram-negative bacterium that can cause pneumonia, urinary tract infections, and bloodstream infections, especially in hospitalized individuals.

Proteus vulgaris

A Gram-negative bacterium found in the human intestines, soil, and water. Known for causing urinary tract infections and wound infections, it is highly motile.

Serratia marcescens

An opportunistic pathogen that produces a red pigment. It can cause respiratory, urinary tract, and wound infections, especially in immunocompromised patients.

Yersinia pestis

The bacterium responsible for plague, transmitted by fleas. It causes bubonic, septicemic, and pneumonic forms of the disease, historically responsible for pandemics.

Vibrio cholerae

The causative agent of cholera, spread through contaminated water. It produces a toxin that leads to severe diarrhea and dehydration.

Chromatium

A genus of purple sulfur bacteria that perform photosynthesis, using hydrogen sulfide instead of water, releasing sulfur as a byproduct.

Bdellovibrio

A predatory bacterium that attacks other Gram-negative bacteria. It invades its prey and replicates inside, eventually killing it.

Desulfovibrio

Sulfate-reducing bacteria found in anoxic environments. They produce hydrogen sulfide gas by reducing sulfate, which has applications in bioremediation.

Cyanobacteria

Also known as blue-green algae, these photosynthetic bacteria produce oxygen. They are important for nitrogen fixation and are found in diverse aquatic and terrestrial environments.

Chlamydia trachomatis

A bacterium responsible for chlamydia, a common sexually transmitted infection, and trachoma, an eye infection that can lead to blindness.

Spirochetes

A group of spiral-shaped bacteria, including pathogens like Treponema pallidum and Borrelia burgdorferi, responsible for diseases such as syphilis and Lyme disease.

Treponema pallidum

The causative agent of syphilis, a sexually transmitted infection. It has a unique spiral shape and moves by corkscrew-like motion.

Borrelia burgdorferi

A spirochete responsible for Lyme disease, transmitted by tick bites. It can cause fever, rash, and long-term joint, heart, and neurological complications.

Leptospira interrogans

A spirochete that causes leptospirosis, transmitted through water contaminated with animal urine. It can cause flu-like symptoms and severe organ damage.

Bacteroides

A genus of Gram-negative anaerobic bacteria in the human gut microbiome. They aid in digestion but can cause infections if they spread to other parts of the body.

Mycoplasma pneumoniae

A small, wall-less bacterium that causes atypical pneumonia (walking pneumonia), characterized by respiratory symptoms and persistent cough.

Streptomyces

A genus of soil bacteria known for producing antibiotics like streptomycin. They have a filamentous structure and contribute to soil decomposition.

Clostridium

A genus of anaerobic, spore-forming bacteria. Some species produce powerful toxins and cause diseases, including botulism and tetanus.

Clostridium tetani

The bacterium that causes tetanus, releasing a neurotoxin that leads to muscle spasms and can be fatal if untreated.

Clostridium botulinum

Produces botulinum toxin, one of the most potent toxins known, causing botulism. The toxin blocks nerve function, leading to paralysis.

Clostridium perfringens

Known for causing gas gangrene and food poisoning, it produces toxins that damage tissue and can lead to rapid spread in wounds.

Bacillus anthracis

The causative agent of anthrax, which can infect the skin, lungs, or gastrointestinal tract. It forms durable spores that are resistant to environmental stresses.

Lactobacillus

A genus of lactic acid bacteria involved in food fermentation and beneficial gut flora. They help maintain a healthy digestive system.

Staphylococcus aureus

A Gram-positive bacterium that can cause skin infections, pneumonia, and toxic shock syndrome. It is known for antibiotic-resistant strains (MRSA).

Streptococcus pyogenes

Causes strep throat, scarlet fever, and rheumatic fever. It produces toxins that can damage tissues and the immune response.

Corynebacterium diphtheriae

The causative agent of diphtheria, a respiratory infection. It releases a toxin that inhibits protein synthesis, leading to cell death.

Mycobacterium tuberculosis

The bacterium that causes tuberculosis (TB). It infects the lungs and can form granulomas, making it difficult to eradicate.

Mycobacterium bovis

Related to M. tuberculosis, it causes TB in cattle and can infect humans through consumption of unpasteurized milk.

Mycobacterium leprae

The causative agent of leprosy, it infects the skin and nerves, leading to severe disfigurement and disability if untreated.