3-4b Bacterial phyla and genera

Rickettsia

Genus in Phylum Proteobacteria, a group of tick-borne bacteria that cause diseases such as Rocky Mountain spotted fever.

Shigella

Genus in Phylum Proteobacteria, a bacteria closely related to Escherichia that produces the diarrhea-causing Shiga toxin.

Spirochetes

Bacterial phylum: Corkscrew shape and movement, due to flagella between two layers of membrane surrounding cell. Vary in size and lifestyle, with some important human pathogens including Borrelia, Treponema, Leptospira.

Proteobacteria

Bacterial phylum: Extremely large and diverse phylum. Gram negative, include a spectrum of metabolic types, environments, etc. Include non oxygenic photosynthesis, nitrogen fixation, related to mitochondria, and some pathogens and microbiome residents.

Firmicutes

Bacterial phylum: Mostly gram positive, mostly cocci but some bacilli. Range of environments and required conditions. Some form endospores. Important in microbiome and as pathogens. Pathogens include some members of Clostridium, Listeria, Staphylococcus, Streptococcus. Enterococcus is symbiont in gut, pathogen elsewhere.

Tenericutes

Bacterial phylum: No peptidoglycan cell wall, evolved from Firmicutes. So, gram negative and floppy in shape, cytoskeleton allows them to move or control shape. Mostly intracellular symbionts or pathogens. Pathogenic genus: Mycoplasma.

Bacteroidetes

Bacterial phylum: gram negative, not spore forming, rod shaped (bacillus), can be aerobic or anaerobic. Widely distributed in environment, major proportion of human gut microbiome.

Chlamydiae

Bacterial phylum: gram negative, tiny ovoid cells, obligate intracellular parasites or symbionts of eukaryotes. Most common bacterial STD in humans. Genus: Chlamydia.

Actinobacteria

Bacterial phylum: gram positive. mostly soil bacteria, some fix nitrogen. Genera of interest: Mycobacterium (acid fast), Nocardia (partially acid fast), Corynebacterium, and Ureaplasma are pathogenic, Streptomyces (soil bacteria) make antibiotics.

Corynebacterium

Genus in Phylum Actinobacteria, commensal members of the microbiome. Pathogen causes diphtheria, one of the diseases covered in the childhood vaccine regimen.

Mycobacterium

Genus in Phylum Actinobacteria, rod shaped and gram negative but acid fast due to high concentration of mycolic acid. Cell wall structure and slow metabolism gives pathogens resistance to most antibiotics and many sanitizing agents. Pathogens cause tuberculosis and leprosy.

Enterococcus

Genus in Phylum Firmicutes, named for living in the gut and cell shape. Lactic acid bacteria, part of healthy gut microbiome. Pathogenic if in other regions of the body.

Staphylococcus

Genus in Phylum Firmicutes, named for the shape of the cells/colonies, most species are part of the skin/mucous membrane microbiome. Includes highly variable strains of S. aureus, including many pathogenic, toxin-producing strains that are often antibiotic resistant. Include MRSA and VRSA.

Lactobacillus

Genus in Phylum Firmicutes, rod shaped, essential members of the human microbiome, especially gut and urogenital.

Listeria

Genus in Phylum Firmicutes, small rod shaped, pathogenic species L. monocytogenes causes food poisoning (gastroenteritis), can lead to septic infection or meningitis.

Pseudomonas

Genus in Phylum Proteobacteria, a widespread, diverse genus. Cell wall structure, efflux pumps, and biofilms make these bacteria resistant to antibiotics. P aeruginosa has become an important opportunistic pathogen, especially in hospital setting.

Brucella

Genus in Phylum Proteobacteria, cause brucellosis, a zoonotic infection that leads to fevers and infection in many systems of the body. These bacteria are found in infected animals, including their meat or milk.

Bordetella

Genus in Phylum Proteobacteria, cause respiratory diseases in humans, including pertussis, one of the childhood vaccine diseases.

Escherichia

Genus in Phylum Proteobacteria, essential component of the gut microbiome, providing Vitamin K to their host. Pathogenic strains can cause severe food poisoning, UTIs.

Campylobacter

Genus in Phylum Proteobacteria, food borne bacteria, found especially in raw chicken, but can contaminate dairy or vegetables. Killed by cooking. Cause acute diarrhea/dysentery, is self limiting.

Salmonella

Genus in Phylum Proteobacteria, intracellular parasites that are common cause of food poisoning. One serotype can cause typhoid fever.

Francisella

Genus in Phylum Proteobacteria, intracellular parasites that cause the disease tularemia. Carried by some insects, can also be passed from infected animal to human, but not human-to-human.

Helicobacter

Genus in Phylum Proteobacteria, live inside the digestive system, causal agent of peptic ulcers and can contribute to stomach cancer.

Vibrio

Genus in Phylum Proteobacteria, named for the bean-shaped cell. These live in water, and can cause food poisoning in undercooked seafood, or from contaminated water, and can invade wounds and cause sepsis.

Yersinia

Genus in Phylum Proteobacteria, one species can be transmitted to humans via fleas from their natural mammalian hosts, and causes plague. This disease was endemic in Eurasian rats and is now endemic in animals in western U.S.

Haemophilus

Genus in Phylum Proteobacteria, part of the healthy mucus membrane microbiome, pathogenic members include H. influenzae and the causative agent of chanchroid.

Neisseria

Genus in Phylum Proteobacteria, part of the mucous membrane microbiome. Pathogens include the bacteria that causes the sexually transmitted disease gonorrhea.

Bartonella

Genus in Phylum Proteobacteria, requires an insect and mammalian host. Humans can be the host, or get the disease from another host such as a cat (cat scratch disease). Symptoms can include fever, endocarditis, bacteremia.

Legionella

Genus in Phylum Proteobacteria, this bacteria includes the pathogen that causes Legionnaires disease and Pontiac fever. The bacteria can contaminate water sources and is transmitted by inhaling water droplets, is not spread from person to person.

Leptospira

Genus in Phylum Spirochaetes, bacteria found in animal urine that can cause leptospirosis in humans.

Treponema

Genus in Phylum Spirochaetes, causes the sexually transmitted disease syphilis, and the skin cutaneous tropical disease yaws.

Borrelia

Genus in Phylum Spirochaetes, numerous species cause Lyme disease and other tick-borne diseases.

Mycoplasma

Genus in Phylum Tenericutes, pathogens: M. pneumoniae causes walking pneumonia, M. genitalium can cause vaginosis.

Bacillus

Genus in phylum Firmicutes, named for cell shape. Endospore forming, pathogens cause anthrax and food poisoning.

Streptococcus

Genus, Phylum Firmicutes, named for shape of cells/colonies, important members of the microbiome. Pathogens cause strep throat, impetigo, and dental caries, as well as dangerous infections like streptococcal toxic shock, necrotizing fasciitis, and pneumonia.

Clostridium

genus in Phylum Firmicutes, endospore forming, rod shaped, pathogens cause botulism, tetanus, food poisoning, cellulitis, gas gangrene.