Pathogenic bacteria

 ( Bacterial Diseases ) 

Pathogenic bacteria are bacteria that can cause disease.

This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and many are Probiotic but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are considered part of the gut flora, with a few hundred species present in each individual human's digestive tract.

The body is continually exposed to many species of bacteria, including beneficial , which grow on the skin and , and , which grow mainly in the soil and in decomposition matter. The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immune system or innate immunity against many microorganisms.

Pathogenic bacteria are specially adapted and endowed with mechanisms for overcoming the normal body defences, and can invade parts of the body, such as the blood, where bacteria are not normally found. Some pathogens invade only the surface epithelium, skin or mucous membrane, but many travel more deeply, spreading through the tissues and disseminating by the lymphatic system and blood streams. In some rare cases a pathogenic microbe can infect an entirely healthy person, but infection usually occurs only if the body's defence mechanisms are damaged by some local trauma or an underlying debilitating disease, such as wounding, intoxication, Chills, fatigue, and malnutrition. In many cases, it is important to differentiate infection and colonization, which is when the bacteria are causing little or no harm.

Caused by Mycobacterium tuberculosis bacteria, one of the with the highest disease burden is tuberculosis, which killed 1.4 million people in 2019, mostly in sub-Saharan Africa. Pathogenic bacteria contribute to other globally important diseases, such as pneumonia, which can be caused by bacteria such as Staphylococcus, Streptococcus and Pseudomonas, and foodborne illnesses, which can be caused by bacteria such as Shigella, Campylobacter, and Salmonella. Pathogenic bacteria also cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy.

Pathogenic bacteria are also the cause of high infant mortality rates in developing countries. A GBD study estimated the global health death rates from (33) bacterial pathogens, finding such infections contributed to one in 8 deaths (or ~7.7 million deaths), which the second largest cause of death globally in 2019.

Most pathogenic bacteria can be grown in cultures and identified by Gram stain and other methods. Bacteria grown in this way are often tested to find which will be an effective treatment for the infection. For hitherto unknown pathogens, Koch's postulates are the standard to establish a causality between a microbe and a disease.

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Diseases Each species has specific effect and causes symptoms in people who are infected. Some people who are infected with a pathogenic bacteria do not have symptoms. Immunocompromised individuals are more susceptible to pathogenic bacteria.

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Pathogenic susceptibility Some pathogenic bacteria cause disease under certain conditions, such as entry through the skin via a cut, through sexual activity or through compromised immune function. Some species of Streptococcus and Staphylococcus are part of the normal human flora and typically reside on healthy skin or in the nasopharyngeal region. Yet these species can potentially initiate skin infections. Streptococcus include sepsis, pneumonia, and meningitis. These infections can become serious creating a systemic inflammatory response resulting in massive vasodilation, shock, and death.

Other bacteria are opportunistic pathogens and cause disease mainly in people with immunosuppression or cystic fibrosis. Examples of these opportunistic pathogens include Pseudomonas aeruginosa, Burkholderia cenocepacia, and Mycobacterium avium.

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Intracellular Obligate intracellular parasites (e.g. Chlamydophila, Ehrlichia, Rickettsia) are only able to grow and replicate inside other cells. Infections due to obligate intracellular bacteria may be asymptomatic, requiring an incubation period. Examples of obligate intracellular bacteria include Rickettsia prowazekii (typhus) and Rickettsia rickettsii, (Rocky Mountain spotted fever).

Chlamydia are intracellular parasites. These pathogens can cause pneumonia or urinary tract infection and may be involved in coronary heart disease.

Other groups of intracellular bacterial pathogens include Salmonella, Neisseria, Brucella, Mycobacterium, Nocardia, Listeria, Francisella, Legionella, and Yersinia pestis. These can exist intracellularly, but can exist outside host cells.

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Infections in specific tissue Bacterial pathogens often cause infection in specific areas of the body. Others are generalists.

• Bacterial vaginosis is a condition of the vaginal microbiota in which an excessive growth of Gardnerella vaginalis and other mostly anaerobic bacteria displace the beneficial Lactobacilli species that maintain healthy vaginal microbial populations.
• Bacterial meningitis is a bacterial inflammation of the meninges, which are the protective membranes covering the brain and spinal cord.
• Bacterial pneumonia is a bacterial infection of the .
• Urinary tract infection is predominantly caused by bacteria. Symptoms include the strong and frequent sensation or urge to urinate, pain during urination, and urine that is cloudy. The most frequent cause is Escherichia coli. Urine is typically sterile but contains a variety of salts and waste products. Bacteria can ascend into the Urinary bladder or kidney and causing cystitis and /ref>
• Bacterial gastroenteritis is caused by enteric, pathogenic bacteria. These pathogenic species are usually distinct from the usually harmless bacteria of the normal gut flora. But a different strain of the same species may be pathogenic. The distinction is sometimes difficult as in the case of Escherichia.
• Bacterial include:
• Impetigo is a highly contagious human skin infection commonly seen in children. Page last reviewed: 17/07/2014 It is caused by Staphylococcus aureus, and Streptococcus pyogenes.Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; & Mitchell, Richard N. (2007). Robbins Basic Pathology (8th ed.). Saunders Elsevier. pp. 843
• Erysipelas is an acute streptococcus infection of the deeper skin layers that spreads via with lymphatic system.
• Cellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by contagious contact, and usually occurs through open skin, cuts, , cracks in the skin, , animal attacks, burns, , intravenous drug injection, or sites of intravenous catheter insertion. In most cases it is the skin on the face or lower legs that is affected, though cellulitis can occur in other tissues.

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Mechanisms of damage The symptoms of disease appear as pathogenic bacteria damage host tissues or interfere with their function. The bacteria can damage host cells directly or indirectly by provoking an immune response that inadvertently damages host cells,

(2026). 9780702040894, Churchill Livingstone. ISBN 9780702040894

or by releasing Microbial toxin.

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Direct Once pathogens attach to host cells, they can cause direct damage as the pathogens use the host cell for nutrients and produce waste products.

(2026). 9780321929150, Pearson Education. ISBN 9780321929150

For example, Streptococcus mutans, a component of dental plaque, metabolizes dietary sugar and produces acid as a waste product. The acid decalcifies the tooth surface to cause dental caries.

(2026). 9780123971883, Academic Press. ISBN 9780123971883

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Toxin production Endotoxins are the lipid portions of lipopolysaccharides that are part of the outer membrane of the cell wall of gram-negative bacteria. Endotoxins are released when the bacteria Lysis, which is why after antibiotic treatment, symptoms can worsen at first as the bacteria are killed and they release their endotoxins. Exotoxins are secreted into the surrounding medium or released when the bacteria die and the cell wall breaks apart.

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Indirect

An excessive or inappropriate immune response triggered by an infection may damage host cells.

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Survival in host

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Nutrients

Iron is required for humans, as well as the growth of most bacteria. To obtain free iron, some pathogens secrete proteins called siderophores, which take the iron away from iron-transport proteins by binding to the iron even more tightly. Once the iron-siderophore complex is formed, it is taken up by siderophore receptors on the bacterial surface and then that iron is brought into the bacterium.

Gerard Tortota (2026). 9780321733603, Pearson. ISBN 9780321733603

Bacterial pathogens also require access to carbon and energy sources for growth. To avoid competition with host cells for glucose which is the main energy source used by human cells, many pathogens including the respiratory pathogen Haemophilus influenzae specialise in using other carbon sources such as Lactic acid that are abundant in the human body

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Identification

Typically identification is done by growing the organism in a wide range of cultures which can take up to 48 hours. The growth is then visually or genomically identified. The cultured organism is then subjected to various assays to observe reactions to help further identify species and strain.

(2026). 9781617798177 ISBN 9781617798177

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Treatment

Bacterial infections may be treated with , which are classified as bacteriocide if they kill bacteria or bacteriostatic if they just prevent bacterial growth. There are many types of antibiotics and each class enzyme inhibitor a process that is different in the pathogen from that found in the host. For example, the antibiotics chloramphenicol and tetracyclin inhibit the bacterial ribosome but not the structurally different eukaryotic ribosome, so they exhibit selective toxicity. Antibiotics are used both in treating human disease and in intensive farming to promote animal growth. Both uses may be contributing to the rapid development of antibiotic resistance in bacterial populations. Phage therapy, using can also be used to treat certain bacterial infections.

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Prevention

Infections can be prevented by antiseptic measures such as sterilizing the skin prior to piercing it with the needle of a syringe and by proper care of indwelling catheters. Surgical and dental instruments are also sterilized to prevent infection by bacteria. Disinfectants such as bleach are used to kill bacteria or other pathogens on surfaces to prevent contamination and further reduce the risk of infection. Bacteria in food are killed by cooking to temperatures above 73 °C (163 °F).

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List of genera and microscopy features

Many genera contain pathogenic bacterial species. They often possess characteristics that help to classify and organize them into groups. The following is a partial listing.

BacillusUnless else specified in boxes then ref is: (2026). 9780781782159, Lippincott Williams & Wilkins. ISBN 9780781782159	Bacillus anthracis Bacillus cereus Positive	Rods	Facultative anaerobic	Extracellular
Bartonella	Bartonella henselae Bartonella quintana Negative	Rods	Aerobic	Facultative intracellular
Bordetella	Bordetella pertussis (2026). 9780781782159, Lippincott Williams & Wilkins. ISBN 9780781782159 Negative	Small coccobacilli	Aerobic	Extracellular
Borrelia	Borrelia burgdorferi Borrelia garinii Borrelia afzelii Borrelia recurrentis Negative, stains poorly	Spirochete	Anaerobic	Extracellular
Brucella	Brucella abortus Brucella canis Brucella melitensis Brucella suis Negative	Coccobacilli	Aerobic	Intracellular
Campylobacter	Campylobacter jejuni Negative	Spiral rods coccoid in older cultures	Microaerophilic	Extracellular
Chlamydia and Chlamydophila	Chlamydia pneumoniae Chlamydia trachomatis Chlamydophila psittaci (not Gram-stained)	Small, round, ovoid	Facultative or strictly aerobic	Obligate intracellular
Clostridium	Clostridium botulinum Clostridioides difficile Clostridium perfringens Clostridium tetani Positive	Large, blunt-ended rods	Obligate anaerobic	Extracellular
Corynebacterium	Corynebacterium diphtheriae Samuel Baron (1996). 9780963117212, University of Texas Medical Branch at Galveston, Galveston, Texas. ISBN 9780963117212 Positive (unevenly)	Rods	Mostly facultative anaerobic	Extracellular
Enterococcus	Enterococcus faecalis Enterococcus faecium Positive	Coccus	Facultative Anaerobic	Extracellular
Escherichia	Escherichia coli Negative	Rods	Facultative anaerobic	Extracellular or Intracellular
Francisella	Francisella tularensis Negative	Coccobacillus	Strictly aerobic	Facultative intracellular
Haemophilus	Haemophilus influenzae Negative	Coccobacilli to long and slender filaments	Facultative anaerobic 5 – 10% CO2	Extracellular
Helicobacter	Helicobacter pylori Negative	Spiral rod	Microaerophile	Extracellular
Legionella	Legionella pneumophila Negative, stains poorly	Cocobacilli	Aerobic	Facultative intracellular
Leptospira	Leptospira interrogans Leptospira santarosai Leptospira weilii Leptospira noguchii Negative, stains poorly	Spirochete	Strictly aerobic	Extracellular
Listeria	Listeria monocytogenes Positive, darkly	Slender, short rods	Facultative Anaerobic	Facultative intracellular
Mycobacterium	Mycobacterium leprae Mycobacterium tuberculosis Mycobacterium ulcerans (none)	Long, slender rods	Aerobic	Intracellular
Mycoplasma	Mycoplasma pneumoniae (none)	Indistinct 'fried egg' appearance, no cell wall	Mostly facultative anaerobic; M. pneumoniae strictly aerobic	Extracellular
Neisseria	Neisseria gonorrhoeae Neisseria meningitidis Negative	Kidney bean-shaped	Aerobic	Gonococcus: facultative intracellular N. meningitidis: extracellular
Pseudomonas Created: 30 September 2005. Last update: 01 April 2013	Pseudomonas aeruginosa Negative	Rods	Obligate aerobic	Extracellular
Rickettsia	Rickettsia rickettsii Negative, stains poorly	Small, rod-like coccobacillary	Aerobic	Obligate intracellular
Salmonella	Salmonella typhi Salmonella typhimurium Negative	Rods	Facultative anaerobic	Facultative intracellular
Shigella	Shigella sonnei Negative	Rods	Facultative anaerobic	Extracellular
Staphylococcus	Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus Positive, darkly	Round Coccus	Facultative anaerobic	Extracellular, facultative intracellular
Streptococcus	Streptococcus agalactiae Streptococcus pneumoniae Streptococcus pyogenes Positive	Ovoid to spherical	Facultative anaerobic	Extracellular
Treponema	Treponema pallidum Negative, stains poorly	Spirochete	Aerobic	Extracellular
Ureaplasma	Ureaplasma urealyticum Stains poorly	Indistinct, 'fried egg' appearance, no cell wall	Anaerobic	Extracellular
Vibrio	Vibrio cholerae Negative	Spiral with single polar flagellum	Facultative anaerobic	Extracellular
Yersinia	Yersinia pestis Yersinia enterocolitica Yersinia pseudotuberculosis Negative, bipolarly	Small rods	Facultative anaerobe	Intracellular

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List of species and clinical characteristics

File:Overall age-standardised mortality rate per 100 000 population for 33 pathogens investigated, 2019.jpg|Overall age-standardised mortality rate per 100 000 population for 33 pathogens investigated, 2019 File:Global number of deaths (A) and YLLs (B), by pathogen and infectious syndrome, 2019.jpg|Global number of deaths (A) and YLLs (B), by pathogen and infectious syndrome, 2019 File:Global number of deaths, by pathogen, age, and sex groups, 2019.jpg|Global number of deaths, by pathogen, age, and sex groups, 2019 This is description of the more common genera and species presented with their clinical characteristics and treatments.

+Species of human pathogenic bacteria
Actinomyces israelii		Oral flora	Actinomycosis: painful and cysts MRSA in the mouth, lungs, or gastrointestinal tract. Bowden GHW (1996). 9780963117212, Univ of Texas Medical Branch. ISBN 9780963117212	Prolonged penicillin G and drainage
Bacillus anthracis		Contact with cattle, sheep, goats and horses Spores enter through inhalation or through abrasions	Anthrax: pulmonary, gastrointestinal and/or cutaneous symptoms. In early infection: Penicillin Doxycycline Ciprofloxacin Raxibacumab	Anthrax vaccine Autoclaving of equipment
Bacteroides fragilis		Gut flora	in gastrointestinal tract, pelvic cavity and	metronidazole	Wound care Aspiration prevention
Bordetella pertussis		Contact with respiratory droplets expelled by infected human hosts.	Whooping cough Secondary bacterial pneumonia such as erythromycin, before paroxysmal stage	Pertussis vaccine, such as in DPT vaccine
Borrelia	B. burgdorferi Borrelia garinii Borrelia afzelii	Ixodes hard ticks Reservoir in mice, other small mammals, and birds	Lyme disease Early localized: erythema migrans Early disseminated: neuroborreliosis, Lyme carditis Late: Lyme arthritis, Achrodermatitis chronica ( B. afzelii only)	Doxycycline for adults, amoxicillin for children, ceftriaxone for neurological involvement	Wearing clothing that limits skin exposure to ticks. Insect repellent. Avoid areas where ticks are found.
	B. recurrentis (2026). 9781259835971, McGraw Hill Education. ISBN 9781259835971 and others	Pediculus humanus corporis body louse ( B. recurrentis only) and Ornithodoros soft ticks	Relapsing fever	Penicillin, tetracycline, doxycycline	Avoid areas where ticks are found Better access to washing facilities Reduce crowding Pesticides
Brucella	Brucella abortus Brucella canis B. melitensis Brucella suis	Direct contact with infected animal Oral, by ingestion of unpasteurized milk or milk products	Brucellosis: mainly fever, muscular pain and	doxycycline streptomycin or gentamicin
Campylobacter jejuni		Fecal–oral from animals (mammals and fowl) Uncooked meat (especially poultry) Contaminated water	Enteritis, bloody diarrhea Guillain–Barré syndrome (muscle weakness)	Treat symptoms Fluoroquinolone such as ciprofloxacin in severe cases	Good hygiene Avoiding contaminated water Pasteurizing milk and milk products Cooking meat (especially poultry)
Chlamydia	C. pneumoniae	Respiratory droplets Atypical pneumonia	Doxycycline Erythromycin None
	C. trachomatis	vaginal sex oral sex anal sex Vertical from mother to newborn(ICN) Direct or contaminated surfaces and flies (trachoma)	Trachoma Neonatal conjunctivitis Neonatal pneumonia Nongonococcal urethritis (NGU) Urethritis Pelvic inflammatory disease Epididymitis Prostatitis Lymphogranuloma venereum (LGV)	Erythromycin (adults) Doxycycline (infants and pregnant women)	Erythromycin or silver nitrate in newborn's eyes Safe sex Abstinence
Chlamydophila psittaci		Inhalation of dust with secretions or feces from birds (e.g. parrots)	Psittacosis, mainly atypical pneumonia	Tetracycline Doxycycline Erythromycin -
Clostridium	C. botulinum	Spores from soil, persevere in Canning food, smoked fish and honey	Botulism: Mainly muscle weakness and paralysis	Antitoxin Penicillin Hyperbaric oxygen Mechanical ventilation	Proper food preservation techniques
	C. difficile	Gut flora, overgrowing when other flora is depleted	Pseudomembranous colitis	Discontinuing responsible antibiotic Vancomycin or metronidazole if severe Fecal bacteriotherapy
	C. perfringens	Spores in soil Vaginal flora and gut flora	Anaerobic cellulitis Gas gangrene Acute food poisoning Gas gangrene: Debridement or amputation Hyperbaric medicine High doses of doxycycline or penicillin G and clindamycin Food poisoning: Supportive care is sufficient	Appropriate food handling
	C. tetani	Spores in soil, skin penetration through wounds	Tetanus: (2012). 9780983263135, Public Health Foundation. . ISBN 9780983263135	Tetanus immune globulin Sedatives Muscle relaxants Mechanical ventilation Penicillin or metronidazole	Tetanus vaccine (such as in the DPT vaccine)
Corynebacterium diphtheriae		respiratory droplets part of human flora	Diphtheria: Fever, sore throat and neck swelling, potentially narrowing airways.	Horse serum antitoxin Erythromycin Penicillin	DPT vaccine
Ehrlichia	Ehrlichia canis E. chaffeensis	Dog tick	Ehrlichiosis: headache, Myalgia, and fatigue	doxycycline rifampin
Enterococcus	E. faecalis E. faecium	Part of gut flora, opportunistic or entering through GI tract or urinary system wounds	Bacterial endocarditis, biliary tract infections, urinary tract infections	Ampicillin (combined with aminoglycoside in endocarditis) Vancomycin	No vaccine Hand washing and other nosocomial prevention
Escherichia	Escherichia coli (generally)	Gut flora, and in urinary tract Spreading extraintestinally or proliferating in the GI tract	Diarrhea Urinary tract infections (UTI) Meningitis in infants Hospital-acquired pneumonia Hospital-acquired sepsis |rowspan=5 UTI: (resistance-tests are required first) Co-trimoxazole Fluoroquinolone, e.g. ciprofloxacin Meningitis: Cephalosporin (e.g. cefotaxime) and gentamicin combination Diarrhea: Antibiotics above shorten duration Electrolyte and fluid replacement	(no vaccine or preventive drug) Cooking ground beef and pasteurizing milk against O157:H7 Hand washing and disinfection
	Enterotoxigenic E. coli (ETEC)	Fecal–oral through food and water Direct physical contact	Traveller's diarrhea
	Enteropathogenic E. coli	Vertical, in utero or at birth	Diarrhea in infants
	Enteroinvasive E.coli (EIEC)	Fecal–oral	Dysentery and fever
	Enterohemorrhagic (EHEC), including	Reservoir in cattle	Dysentery Hemolytic-uremic syndrome
Francisella tularensis		vector-borne by arthropods Infected wild or domestic animals, birds or house pets Tularemia: Fever, ulceration at entry site and/or lymphadenopathy. Page last reviewed: October 26, 2015 Can cause severe pneumonia.	Streptomycin Gentamicin	Avoiding insect vectors Precautions when handling wild animals or animal products
Haemophilus influenzae		Droplet contact Human flora of e.g. upper respiratory tract	Bacterial meningitis Upper respiratory tract infections Pneumonia, bronchitis Septic arthritis in infants Meningitis: (resistance-tests are required first) Third generation cephalosporin, e.g. cefotaxime or ceftriaxone Ampicillin and sulbactam combination	Hib vaccine to infants Rifampin prophylactically
Helicobacter pylori		Colonizing stomach Unclear person-to-person transmission	Peptic ulcer Chronic gastritis Risk factor for gastric carcinoma and gastric B-cell lymphoma	Tetracycline, metronidazole and bismuth salt combination (No vaccine or preventive drug)
Klebsiella pneumoniae		Mouth, skin flora, and gut flora. (2026). 9780838585290, McGraw Hill. ISBN 9780838585290 Pneumonia upon aspiration	Klebsiella pneumonia, with significant lung necrosis and hemoptysis Hospital-acquired urinary tract infection and sepsis	3rd generation cephalosporin ciprofloxacin	hand hygiene. Page last reviewed: November 24, 2010. Page last updated: August 27, 2012
Legionella pneumophila		Droplet contact, from e.g. , humidifiers, air conditioners and water distribution systems	Legionnaires' disease Pontiac fever	, such as erythromycin Rifampin (no vaccine or preventive drug) Heating water
Leptospira species		Food and water contaminated by urine from infected wild or domestic animals. Leptospira survives for weeks in fresh water and moist soil.	Leptospirosis: , muscle pains, and ; possible jaundice, kidney failure, pulmonary hemorrhage, and meningitis.	Doxycycline for mild cases (2026). 9781259835971, McGraw Hill Education. ISBN 9781259835971 Intravenous penicillin for severe cases Vaccine not widely used Doxycycline Prevention of exposure Rodent control
Listeria monocytogenes		Raw milk or cheese, ground meats, poultry Vertically to newborn or fetus	Listeriosis: *Meningitis *Sepsis	Ampicillin Co-trimoxazole (no vaccine) Proper food preparation and handling
Mycobacterium	M. leprae	Prolonged human-human contact, e.g. through exudates from skin lesions to abrasion of other person	Leprosy (Hansen's disease): of the nerves, respiratory tract, skin, and eyes. Tuberculoid form: Dapsone and rifampin Lepromatous form: Clofazimine	BCG vaccine shows some effects
	M. tuberculosis	Droplet contact	Tuberculosis: chronic cough with hemoptysis sputum, fever, night sweats, and weight loss	(difficult, see Tuberculosis treatment for more details) Standard "short" course: First 2 months, combination: Isoniazid Rifampicin Pyrazinamide Ethambutol Further 4 months, combination: Isoniazid Rifampicin	BCG vaccine Isoniazid
Mycoplasma pneumoniae		Human flora Respiratory droplets	Mycoplasma pneumonia	Doxycycline and erythromycin
Neisseria	N. gonorrhoeae	Sexually transmitted vertical in birth	Gonorrhea *Urethritis (men) *Pelvic inflammatory disease (women) Ophthalmia neonatorum Septic arthritis Uncomplicated gonorrhea: Ceftriaxone Tetracycline, e.g. doxycycline if also chlamydia is suspected Spectinomycin for resistance or patient allergy to cephalosporin Ophthalmia neonatorum: Erythromycin + ceftriaxone	(No vaccine) Safe sex Erythromycin into eyes of newborn at risk
	N. meningitidis	Droplet transmission	Meningococcal disease including meningitis Sepsis, including Waterhouse-Friderichsen syndrome	Penicillin G Ceftriaxone	NmVac4-A/C/Y/W-135 vaccine Rifampin
Pseudomonas aeruginosa		Opportunistic; Infects damaged tissues or people with immunodeficiency.	Pseudomonas infection: Pneumonia Urinary tract infection Keratitis Endocarditis Osteomyelitis Burn wound infection Sepsis Malignant external otitis	Anti-pseudomonal penicillins such as ticarcillin Aminoglycoside (no vaccine) Topical silver sulfadiazine for burn wounds
Nocardia asteroides		In soil	Nocardiosis: Pneumonia, endocarditis, keratitis, neurological or lymphocutaneous infection	TMP/SMX
Rickettsia rickettsii		Wood or dog tick	Rocky mountain spotted fever	Doxycycline Chloramphenicol (no preventive drug or approved vaccine) Vector control, such as clothing Prompt removal of attached ticks
Salmonella	Salmonella typhi	Fecal–oral route, through food or water	Typhoid fever type salmonellosis (fever, abdominal pain, hepatosplenomegaly, rose spots) Chronic carrier state	Ceftriaxone Fluoroquinolones, e.g. ciprofloxacin	Ty21a and ViCPS vaccines Hygiene and food preparation
	Other Salmonella species e.g. S. typhimurium	Fecal–oral Food contaminated by fowl (e.g. uncooked eggs) or turtles	Salmonellosis with gastroenteritis Paratyphoid fever Osteomyelitis in people with sickle cells Sepsis	Fluid and electrolyte replacement for diarrhea Antibiotics (in neonates and Immunodeficiency): * Ciprofloxacin * Ceftriaxone * TMP/SMX * Azithromycin (No vaccine or preventive drug) Proper sewage disposal Food preparation Good personal hygiene
Shigella	Shigella sonnei S. dysenteriae	Fecal–oral	Shigellosis (bacillary dysentery)	Fluid and electrolyte replacement Fluoroquinolone such as ciprofloxacin if severe	Protection of water and food supplies Vaccines are in trial stage Institut Pasteur Press Office - Vaccine against shigellosis (bacillary dysentery):a promising clinical trial 15 January 2009. Retrieved on 27 February 2009
Staphylococcus	aureus	Human flora on Mucous membrane in e.g. anterior nares, skin and vagina, entering through wound Coagulase-positive staphylococcal infections: Skin infections, including impetigo Acute infective endocarditis Septis Necrotizing pneumonia Meningitis Osteomyelitis Toxinoses Scalded skin syndrome Toxic shock syndrome Staphylococcal food poisoning	Incision and drainage of localized lesions Nafcillin, oxacillin, methicillin Vancomycin for Methicillin-resistant (MRSA) (no vaccine or preventive drug) Barrier precautions, washing hands and fomite disinfection in hospitals
	epidermidis	Human flora in skin, anterior nares and mucous membranes	Infections of implanted Prosthesis (e.g. heart valves and joints) and catheters	Vancomycin None
	saprophyticus	Part of normal vaginal flora	Cystitis in women	TMP/SMX or norfloxacin None
Streptococcus	agalactiae	Human flora in vagina, mucous membranes, rectum Vertically during childbirth Sexually	Neonatal meningitis Neonatal sepsis Neonatal pneumonia Endometritis in postpartum women Opportunistic infections with sepsis and pneumonia	Penicillin G Aminoglycoside in case of lethal infection None
	pneumoniae	Respiratory droplets Human flora in nasopharynx (spreading in immunocompromised)	Acute bacterial pneumonia & meningitis in adults Otitis media and sinusitis in children Sepsis	Penicillin G	23-serotype vaccine for adults (PPV) Heptavalent conjugated vaccine for children (PCV)
	pyogenes	Respiratory droplets Direct physical contact with impetigo lesions	Streptococcal pharyngitis Sepsis Scarlet fever Rheumatic fever Impetigo and erysipelas Puerperal fever Necrotizing fasciitis Poststreptococcal glomerulonephritis	Penicillin G or Penicillin V Macrolide, e.g. clarithromycin or erythromycin in penicillin allergy Drainage and debridement for necrotizing fasciitis No vaccine Rapid antibiotic treatment helps prevent rheumatic fever
	viridans	Oral flora, penetration through abrasions	Subacute bacterial endocarditis Dental cavities of brain and liver Penicillin G
Treponema pallidum subspecies pallidum		Sexual Vertical (from mother to fetus)	Syphilis: First a chancre, (a painless skin ulceration), then diffuse rash. Later: gummas (soft growths), neurological, or heart symptoms. Congenital syphilis	Penicillin G Doxycycline if penicillin allergy	Penicillin offered to recent sexual partners Antibiotics to pregnant women if risk of transmitting to child No vaccine available Safe sex
Vibrio cholerae		Fecal–oral route Contaminated water and raw seafood	Cholera: Severe "rice water" diarrhea	Fluid and electrolyte replacement Doxycycline	Proper sanitation Adequate food preparation
Yersinia pestis		from animals Ingestion of animal tissues Respiratory droplets Plague: Bubonic plague Pneumonic plague	Streptomycin primarily Tetracyclin Supportive therapy for shock	Plague vaccine Minimize exposure to rodents and fleas

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Genetic transformation

/ref> Natural transformation is a bacterial adaptation for transferring DNA from one cell to another. This process includes the uptake of exogenous DNA from a donor cell by a recipient cell and its incorporation into the recipient cell's genome by recombination. Transformation appears to be an adaptation for repairing damage in the recipient cell's DNA. Among pathogenic bacteria, transformation capability likely serves as an adaptation that facilitates survival and infectivity. The pathogenic bacteria able to carry out natural genetic transformation (of those listed in the table) are Campylobacter jejuni, Enterococcus faecalis, Haemophilus influenzae, Helicobacter pylori, Klebsiella pneumoniae, Legionella pneumophila, Neisseria gonorrhoeae, Neisseria meningitidis, Staphylococcus aureus, Streptococcus pneumoniae and Vibrio cholerae.

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See also

• Human microbiome project
• List of antibiotics
• Pathogenic viruses

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Notes

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External links

• Bacterial Pathogen Pronunciation by Neal R. Chamberlain, Ph.D. at A.T. Still University
• Pathogenic bacteria genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID

Categories: Bacterial Diseases

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