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File:Clostridium tetani 01.png

Clostridium tetani

Bacterial infection
Classification and external resources
MeSH D001424

Pathogenic bacteria are bacteria that cause bacterial infection which may lead to bacterial disorders of interest to psychologists. This article deals with human pathogenic bacteria.

Although the vast majority of bacteria are harmless or beneficial, quite a few bacteria are pathogenic. One of the bacterial diseases with highest disease burden is tuberculosis, caused by the bacterium Mycobacterium tuberculosis, which kills about 2 million people a year, mostly in sub-Saharan Africa. Pathogenic bacteria contribute to other globally important diseases, such as pneumonia, which can be caused by bacteria such as 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.

Koch's postulates are criteria designed to establish a causal relationship between a causative microbe and a disease.


Each pathogenic species has a characteristic spectrum of interactions with its human hosts.

Conditionally pathogenic

Conditionally pathogenic bacteria are only pathogenic under certain conditions, such as a wound that allows for entry into the blood, or a decrease in immune function.

For example, Staphylococcus or Streptococcus are also part of the normal human flora and usually exist on the skin or in the nose without causing disease, but can potentially cause skin infections, pneumonia, meningitis, and even overwhelming sepsis, a systemic inflammatory response producing shock, massive vasodilation and death.[1]

Some species of bacteria, such as Pseudomonas aeruginosa, Burkholderia cenocepacia, and Mycobacterium avium, are opportunistic pathogens and cause disease mainly in people suffering from immunosuppression or cystic fibrosis.[2][3]


Other organisms invariably cause disease in humans, such as obligate intracellular parasites (e.g. Chlamydophila, Ehrlichia, Rickettsia) that are able to grow and reproduce only within the cells of other organisms. Still, infections with intracellular bacteria may be asymptomatic, such as during the incubation period. An example of intracellular bacteria is Rickettsia. One species of Rickettsia causes typhus, while another causes Rocky Mountain spotted fever.

Chlamydia, another phylum of obligate intracellular parasites, contains species that can cause pneumonia or urinary tract infection and may be involved in coronary heart disease.[4]

Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, and Yersinia pestis can exist intracellularly, though they are facultative (not obligate) intracellular parasites.

By location

Following is a list of bacterial infections classified by location in the body:

  • Bacterial vaginosis is a disease of the vagina caused by an imbalance of naturally occurring bacterial flora and is often confused with yeast infection (candidiasis), or infection with Trichomonas vaginalis (trichomoniasis), which are not caused by bacteria.[5][6]
  • Bacterial meningitis is a bacterial inflammation of the meninges, that is, the protective membranes covering the brain and spinal cord.
  • Bacterial pneumonia is a bacterial infection of the lungs.
  • Urinary tract infection is almost exclusively caused by bacteria. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine.[7] The main causal agent is Escherichia coli. Although urine contains a variety of fluids, salts, and waste products, it does not usually have bacteria in it,[8] but when bacteria get into the bladder or kidney and multiply in the urine, they may cause a UTI.
  • Bacterial gastroenteritis is caused by pathogenic enteric bacteria. Such pathogenic enteric bacteria are generally distinguished from the usually harmless bacteria of the normal gut flora, but the distinction is often not fully clear, and Escherichia, for example, can belong to either group.
  • Bacterial skin infections include:
    • Impetigo is a highly contagious bacterial skin infection most common among pre-school children.[9] It is primarily caused by Staphylococcus aureus, and sometimes by Streptococcus pyogenes.[10]
    • Erysipelas is an acute streptococcus bacterial infection[11] of the deep epidermis with lymphatic spread.
    • Cellulitis is a diffuse inflammation[12] of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters, burns, insect bites, surgical wounds, intravenous drug injection, or sites of intravenous catheter insertion. Skin on the face or lower legs is most commonly affected by this infection, though cellulitis can occur on any part of the body.


Main article: Antibiotics
See also overview list below

Bacterial infections may be treated with antibiotics, which are classified as bacteriocidal if they kill bacteria or bacteriostatic if they just prevent bacterial growth. There are many types of antibiotics and each class inhibits 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.[13] 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.[14] Phage therapy can also be used to treat certain bacterial infections.[15] 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).

List of pathogenic bacteria by basic laboratory characteristics

Following are the genera that contain the most important human pathogenic bacteria species:[16]

Genus Important species Gram staining Shape Capsulation Bonding tendency Motility Respiration Growth medium Intra/Extracellular
  • Bordetella pertussis
Gram-negative Small coccobacilli Encapsulated singly or in pairs aerobic Regan-Lowe agar extracellular
  • Borrelia burgdorferi
Gram-negative, but stains poorly spirochete Long, slender, flexible, spiral- or corkscrew-shaped rods highly motile anaerobic (difficult to culture) extracellular
  • Brucella abortus
  • Brucella canis
  • Brucella melitensis
  • Brucella suis
Gram-negative Small coccobacilli Unencapsulated singly or in pairs non-motile aerobic Blood agar intracellular
  • Campylobacter jejuni
Gram-negative Curved, spiral, or S-shaped
bacilli with single, polar flagellum
Unencapsulated Singly characteristic darting motion microaerophilic Blood agar inhibiting other fecal flora extracellular
Chlamydia and Chlamydophila
  • Chlamydia pneumoniae
  • Chlamydia trachomatis
  • Chlamydophila psittaci
(not Gram-stained) Small, round, ovoid Unencapsulated motile Facultative or strictly aerobic Obligate intracellular
  • Clostridium botulinum
  • Clostridium difficile
  • Clostridium perfringens
  • Clostridium tetani
Gram-positive Large, blunt-ended rods Normally encapsulated mostly motile Obligate anaerobic Anaerobic blood agar extracellular
  • Corynebacterium diphtheriae
Gram-positive (unevenly) Small, slender, pleomorphic rods Unencapsulated clumps looking like Chinese characters or a picket fence nonmotile Mostly facultative anaerobic Aerobically on Tinsdale agar extracellular
  • Enterococcus faecalis
  • Enterococcus faecium
Gram-positive Round to ovoid (cocci) pairs or chains Non-motile Facultative Anaerobic 6.5% NaCl, bile-esculin agar extracellular
Escherichia Gram-negative Short rods (bacilli) Encapsulated and Unencapsulated Normally motile Facultative anaerobic MacConkey agar extracellular or intracellular
  • Francisella tularensis
Gram-negative Small, pleomorphic coccobacillus Encapsulated Non-motile strictly aerobic (rarely cultured) Facultative intracellular
  • Haemophilus influenzae
Gram-negative Ranging from small coccobacillus to long, slender filaments Encapsulated or Unencapsulated Non-motile Chocolate agar with hemin and NAD+ extracellular
Helicobacter Gram-negative Curved or spiral rods
pultiple polar flagella
rapid, corkscrew motility Microaerophile Medium containing antibiotics against other fecal flora extracellular
  • Legionella pneumophila
Gram-negative, but stains poorly Slender rod in nature, cocobacillary in laboratory.
monotrichious flagella
unencapsulated motile aerobic Specialized medium facultative intracellular
  • Leptospira interrogans
Gram-negative, but stains poorly Long, very slender, flexible, spiral- or corkscrew-shaped rods Highly motile Strictly aerobic Specialized medium extracellular
  • Listeria monocytogenes
Gram-positive, darkly Slender, short rods diplobacilli or short chains Distinct tumbling motility in liquid medium Facultative Anaerobic enriched medium intracellular
  • Mycobacterium leprae
  • Mycobacterium tuberculosis
  • Mycobacterium ulcerans
(none) Long, slender rods Unencapsulated nonmotile aerobic M. tuberculosis: Lowenstein-Jensen agar
M. leprae: (none)
  • Mycoplasma pneumoniae
(none) Plastic, pleomorphic Encapsulated singly or in pairs Mostly facultative anaerobic; M.pneumoniae strictly aerobic (rarely cultured) extracellular
  • Neisseria gonorrhoeae
  • Neisseria meningitidis
Gram-negative Kidney bean-shaped Encapsulated or Unencapsulated diplococci Non-motile aerobic Thayer-Martin agar Gonococcus: facultative intracellular
N. meningitidis
: extracellular
  • Pseudomonas aeruginosa
Gram-negative rods encapsulated motile Obligate aerobic MacConkey agar extracellular
  • Rickettsia rickettsii
Gram-negative, but stains poorly Small, rod-like coccobacillary Slime/microcapsule Non-motile Aerobic (rarely cultured) Obligate intracellular
  • Salmonella typhi
  • Salmonella typhimurium
Gram-negative Bacilli Encapsulated Normally motile Facultative anaerobic MacConkey agar Facultative intracellular
  • Shigella sonnei
Gram-negative rods Unencapsulated Non-motile Facultative anaerobic Hektoen agar extracellular
  • Staphylococcus aureus
  • Staphylococcus epidermidis
  • Staphylococcus saprophyticus
Gram-positive, darkly Round cocci Encapsulated or Unencapsulated in bunches like grapes Non-motile Facultative anaerobic enriched medium (broth and/or blood) extracellular
  • Streptococcus agalactiae
  • Streptococcus pneumoniae
  • Streptococcus pyogenes
Gram-positive ovoid to spherical Encapsulated or Unencapsulated pairs or chains nonmotile Facultative anaerobic blood agar extracellular
  • Treponema pallidum
Gram-negative, but stains poorly Long, slender, flexible, spiral- or corkscrew-shaped rods highly motile Aerobic none extracellular
  • Vibrio cholerae
Gram-negative Short, curved, rod-shaped with single polar flagellum Unencapsulated rapidly motile Facultative anaerobic blood- or MacConkey agar. Stimulated by NaCl extracellular
  • Yersinia pestis
Gram-negative, stains bipolarly Small rods encapsulated nonmotile Facultative Anaerobe MacConkey or CIN agar Intracellular

List of pathogenic bacteria by clinical characteristics

This is a rather clinical description of the species presented in the previous section, containing the main examples of transmission, diseases, treatment, prevention and laboratory diagnosis, which all can differ substantially among the species of the same genus.

Species of human pathogenic bacteria[16]
Species Transmission Diseases Treatment Prevention laboratory diagnosis
Bacillus anthracis
  • Contact with sheep, goats and horses
  • Inhalation or skin penetration through abrasions of spore-contaminated dust
  • Cutaneous anthrax
  • Pulmonary anthrax
  • Gastrointestinal anthrax
In early infection:
  • Anthrax vaccine
  • autoclaving of instruments
  • Large, grayish, nonhemolytic colonies with irregular borders on blood agar
  • Direct immunofluorescence
Bordetella pertussis
  • Contact with respiratory droplets expelled by infected human hosts.
  • Whooping cough


  • Secondary bacterial pneumonia
Macrolide antibiotics
  • Azithromycin
  • Erythromycin
  • Clarithromycin
  • Pertussis vaccine, DPT vaccine
Borrelia burgdorferi Ixodes ticks
reservoir in deer, mice and other rodents
  • Early stages:
  • If arthritic symptoms have appeared:
    • Longer courses of antibiotics
  • Lyme vaccine
  • wearing clothing that limits skin exposure to ticks
  • insect repellent
  • Microscopy using Giemsa or Wright stain
  • PCR
  • serology (low precision rate)
  • Brucella abortus
  • Brucella canis
  • Brucella melitensis
  • Brucella suis
  • Direct contact with infected animal
  • Oral, by ingestion of unpasteurized milk or milk products
  • Brucellosis
Combination therapy of: -
  • Culture (difficult and time consuming)
  • Agglutination serology
Campylobacter jejuni
  • Fecal/oral from animals (mammals and fowl)
  • Contaminated meat (especially poultry)
  • Contaminated water
  • Acute enteritis
  • Symptomatically by fluid and electrolyte replacement
  • Ciprofloxacin in severe cases
No available vaccine
  • Good hygiene
  • Avoiding contaminated water
  • Pasteurizing milk and milk products
  • Cooking meat (especially poultry)
  • Finding campylobacter in feces
Chlamydia pneumoniae
  • Respiratory droplets
Community-acquired respiratory infection None None for routine use
Chlamydia trachomatis
  • Sexual (NGU, LGV)
  • Direct or contaminated surfaces and flies (trachoma)
  • Passage through birth canal (ICN)
  • Nongonococcal urethritis (NGU)
  • Lymphogranuloma venereum (LGV)
  • Trachoma
  • Inclusion conjunctivitis of the newborn (ICN)
No vaccine
  • Erythromycin or silver nitrate in newborn's eyes
  • Safe sex
  • Cellular cytoplasmic inclusions by immunofluorescence
  • DNA hybridization
  • ELISA for lipopolysaccharides
Chlamydophila psittaci Inhalation of dust with secretions or feces from birds (e.g. parrots) Psittacosis -
  • Rise in antibody titre
    • Complement fixation
    • indirect immunofluorescence
Clostridium botulinum Spores from soil and aquatic sediments contaminating vegetables, meat and fish
  • Proper food preservation techniques
  • Mouse inoculation detects toxin from food, intestinal contents or serum
  • Culture in standard aerobic culture
Clostridium difficile
  • Spores both indoors and outdoors
  • Human flora, overgrowing when other flora is depleted
  • Pseudomembranous colitis
  • Discontinuing predisposing antibiotic
  • Fluid and electrolyte replacement
  • Vancomycin or metronidazole if severe
  • ELISA for Toxin ELISA for toxin A or B
  • Endoscopy for pseudomembrane
Clostridium perfringens
  • Spores in soil
  • Human flora in vagina and GI tract
  • Gas gangrene
  • Acute food poisoning
  • Anaerobic cellulitis
Gas gangrene:

Food poisoning:

  • Self-limiting; Supportive care is sufficient
Appropriate food handling
  • Microscopically
  • Blood agar culture, forming double-zone β-hemolysis
  • Sugar fermentation
  • Organic acid production
Clostridium tetani
  • Spores in soil infecting puncture wounds, severe burns or surgery
  • DPT vaccine
Corynebacterium diphtheriae
  • Respiratory droplets
  • Part of human flora
  • Diphtheria
  • DPT vaccine
(no rapid)
  • Culture on Tinsdale agar, followed by immunologic precipitin reaction
Enterococcus faecalis and Enterococcus faecium
  • Part of human flora, opportunistic or entering through GI tract or urinary system wounds
  • Nosocomial infections
  • Penicillin and an aminoglycoside
  • Vancomycin
  • Quinupristin and dalfopristin
No vaccine
  • Hand washing and other nosocomial prevention
  • Culture in 6.5% NaCl
  • Can hydrolyze esculin in presence of bile
Escherichia coli (generally)
  • Part of gut flora, spreading extraintestinally or proliferating in the GI tract
  • Urinary tract infections (UTI)
  • Diarrhea
  • Meningitis in infants

(resistance-tests are required first)


  • Cephalosporin (e.g. cefotaxime) and gentamicin combination


  • Antibiotics above shorten duration
  • Electrolyte and fluid replacement
(no vaccine or preventive drug)
  • Food and water preparation
    • Cooking ground beef and pasteurizing milk against O157:H7
  • Hand washing and disinfection
  • Culture on MacConkey agar and study carbohydrate fermentation patterns:
    • Lactose fermentation (most E. coli strains)
    • Gas production in glucose fermentation
    • Mannitol fermentation
Enterotoxigenic Escherichia coli (ETEC)
  • Fecal-oral through food and water
  • Direct physical contact
  • Traveller's diarrhea
Enteropathogenic E. coli
  • Diarrhea in infants
E. coli O157:H7
  • Reservoir in cattle
  • Hemorrhagic colitis
  • Hemolytic-uremic syndrome
Francisella tularensis
  • vector-borne by arthropods
  • Infected wild or domestic animals, birds or house pets
  • Tularemia
  • Streptomycin
  • Gentamicin
  • Avoiding insect vectors
  • Precautions when handling wild animals or animal products
(rarely cultured)
  • Serology
Haemophilus influenzae
  • Droplet contact
  • Human flora of e.g. upper respiratory tract

(resistance-tests are required first)

  • Third generation cephalosporin, e.g. cefotaxime or ceftriaxone
  • Ampicillin and sulbactam combination
  • Hib vaccine to infants
  • Rifampin prophylactically
  • Culture on chocolate agar with hemin (factor X) and NAD+ (factor V)
  • Quellung reaction
  • Immunofluorescence staining of capsule
  • Detection of capsular antigen in CSF or other body fluids
Helicobacter pylori
  • Colonizing stomach
  • Unclear person-to-person transmission
  • Peptic ulcer
  • Risk factor for gastric carcinoma and gastric B-cell lymphoma
  • Tetracycline, metronidazole and bismuth salt combination
(No vaccine or preventive drug)
  • Microscopically
    • Corkscrew movement
  • Urease-positivity by radioactively labeled urea
  • Serology by ELISA
Legionella pneumophila
  • Droplet contact, from e.g. cooling towers, humidifiers, air conditioners and water distribution systems
  • Legionnaire's Disease
  • Pontiac fever
  • Macrolides, e.g. erythromycin or azithromycin
  • Fluoroquinolones
(no vaccine or preventive drug)

Heating water

  • Culture from respiratory secretions on buffered charcoal yeast extract enriched with L-cysteine, iron and α-ketoglutarate
  • Serology, including direct immunofluorescence and radioimmunoassay for antigen in urine
  • Hybridization to ribosomal RNA using DNA probe
Leptospira interrogans
  • Food and water contaminated by e.g. urine from wild or domestic animals. Leptospira survives for weeks in stagnant water.
  • Leptospirosis
(no vaccine)

Prevention of exposure

  • Rodent control
  • Dark-field microscopy on fresh blood smear (but doesn't stain well)
  • Serologic agglutionation tests
Listeria monocytogenes
  • Dairy products, ground meats, poultry
  • Vertical to newborn or fetus
  • Listeriosis
  • Ampicillin
  • Co-trimoxazole
(no vaccine)
  • Proper food preparation and handling
Isolation from e.g. blood and CSF
  • Beta-hemolysis and catalase production on blood agar
  • Microscopy for morphology and motility
Mycobacterium leprae
  • Prolonged human-human contact, e.g. through exudates from skin lesions to abrasion of other person
  • Leprosy (Hansen's disease)
Tuberculoid form:
  • Dapsone and rifampin

Lepromatous form:

  • Clofazimine
  • BCG vaccine shows some effects
Tuberculoid form:
Hard to isolate (diagnosis on clinical findings and histology of biopsies)

Lepromatous form:

  • Acid-fast staining from e.g. skin scrapings
Mycobacterium tuberculosis
  • Droplet contact

(difficult, see Tuberculosis treatment for more details)

Standard "short" course:

  • First 2 months, combination:
  • Further 4 months, combination:
  • Ziehl-Neelsen stain showing acid-fast bacteria
  • Hybridization probes for DNA, succeeded by PCR
  • Culture on Lowenstein-Jensen agar
Mycoplasma pneumoniae
  • Human flora
  • Droplet contact
  • Mycoplasma pneumonia
(difficult to culture)
  • Serologic tests, e.g. complement fixation test
  • DNA probes on sputum specimens
Neisseria gonorrhoeae
  • Gonorrhea
  • 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:

  • Tetracycline or erythromycin into eyes
(No vaccine)
  • Safe sex
  • Tetracycline or erythromycin into eyes of newborn at risk
  • Gram-negative diplococci in neutrophils from urethral exudates
  • Oxidase test on culture on Thayer-Martin agar under increased oxygen tension
  • Fermentation of glucose but not maltose
Neisseria meningitidis
  • Respiratory droplets
  • Meningococcal disease including meningitis
  • Waterhouse-Friderichsen syndrome
  • Penicillin G
  • Cefotaxime
  • Ceftriaxone
  • NmVac4-A/C/Y/W-135 vaccine
  • Rifampin
  • Microscopy showing gram-negative diplococci, often with PMNs
  • Culture on chocolate agar, giving positive oxidase test and fermentation of glucose and maltose in 5% CO2 in air
Pseudomonas aeruginosa Infects damaged tissues or people with reduced immunity.
  • Pseudomonas infection

Localized to eye, ear, skin, urinary, respiratory or gastrointestinal tract or CNS, or systemic with bacteremia, secondary pneumonia bone and joint infections, endocarditis, skin, soft tissue or CNS infections.

(no vaccine)
  • Topical silver sulfadiazine for burn wounds
  • Colourless colonies on MacConkey agar.
  • Production of pyocyanine and fluorescein
  • Positive oxidase test. No lactose fermentation.
Rickettsia rickettsii
  • Bite of infected wood or dog tick
  • Rocky mountain spotted fever
(no preventive drug or approved vaccine)
  • Vector control, such as clothing
  • Prompt removal of attached ticks
Salmonella typhi Human-human
  • Fecal-oral through food or water
  • Typhoid fever type salmonellosis (dysentery, colitis)
  • Ty21a and ViCPS vaccines
  • Hygiene and food preparation
  • Isolation from blood, feces, bone marrow, urine or rose spots on skin
  • Colorless, non-lactose fermenting colonies on MacConkey agar
  • Serology for antibodies against O antigen
Salmonella typhimurium
  • Fecal-oral
  • Food contaminated by fowl (e.g. eggs), pets and other animals
  • Fluid and electrolyte replacement for severe diarrhea
  • Antibiotics (in immunocompromised to prevent systemic spread)
(No vaccine or preventive drug)
  • Proper sewage disposal
  • Food preparation
  • Good personal hygiene
  • Colourless colonies on MacConkey agar
Shigella sonnei
  • Fecal-oral
  • Flies
  • Contaminated food or water
  • Bacillary dysentery/Shigellosis
  • Protection of water and food supplies
  • Vaccines are in trial stage[17]
  • Culture on Hektoen agar or other media for intestinal pathogens
Staphylococcus aureus
  • Human flora on mucosae in e.g. anterior nares and vagina, entering through wound
Coagulase-positive staphylococcal infections:
  • Localized skin infections
  • Diffuse skin infection (Impetigo)
  • Deep, localized infections
  • Acute infective endocarditis
  • Septicemia
  • Necrotizing pneumonia
  • Toxinoses
    • Toxic shock syndrome
    • Staphylococcal food poisoning
  • Incision and drainage of localized lesions
  • Nafcillin and oxacillin
  • Vancomycin for Methicillin-resistant (MRSA)
(no vaccine or preventive drug)
  • Barrier precautions, washing hands and fomite disinfection in hospitals
  • Microscopy showing strongly positive Gram stained cells in grape-like clusters
  • Positive Catalase test and coagulase test
  • Culture on enriched media producing deep yellow, hemolytic colonies
Staphylococcus epidermidis Human flora in skin and anterior nares
  • Infections of implanted prostheses, e.g. heart valves and catheters
  • Vancomycin
  • Microscopy showing strongly positive Gram stained cells in grape-like clusters
  • Positive Catalase test but negative coagulase test
  • Novobiocin-sensitivity (S. epidermidis)
  • Novobiocin-resistance (S. saprophyticus)
  • Culture on enriched media producing white, nonhemolytic colonies
Staphylococcus saprophyticus Part of normal vaginal flora
  • Penicillin G
Streptococcus agalactiae Human flora in vagina or urethral mucous membranes, rectum
  • Vertical transmission by birth
  • Sexual
  • Culture showing large colonies with β-hemolysis
  • Negative catalase test
  • Hydrolyzes sodium hippurate
Streptococcus pneumoniae
  • Respiratory droplets
  • Often human flora in nasopharynx (spreading in immunocompromised)
  • Penicillin G
  • Vancomycin for resistant strains
  • 23-serotype vaccine for adults (PPV)
  • Heptavalent conjugated vaccine for children (PCV)
  • Microscopy showing gram-positive, encapsulated lancet-shaped diplococci
  • α-hemolysis on blood agar, bile-soluble, optochin-sensitive
  • Positive Quellung reaction
Streptococcus pyogenes
  • Respiratory droplets
  • Direct physical contact with impetigo lesions
  • Streptococcal pharyngitis
  • Scarlet fever
  • Rheumatic fever
  • Impetigo and erysipelas
  • Puerperal fever
  • Necrotizing fasciitis
  • Penicillin G
  • Macrolide, e.g. clarithromycin or azithromycin in penicillin allergy
  • Drainage and debridement for Necrotizing fasciitis
No vaccine
  • Rapid antibiotic treatment helps prevent rheumatic fever
  • Culture on sheep blood agar forming small, opalescent surrounded by large zone of β-hemolysis
  • Serology for ASO
  • Very bacitracin-sensitive
Treponema pallidum
  • Sexual
  • Penicillin G
  • Erythromycin or tetracycline if penicillin allergy
No preventive drug or vaccine
  • Safe sex
  • Antibiotics to pregnant women at risk of transmitting congenital syphilis
Cannot be cultured or viewed in gram-stained smear
  • Dark field microscopy
  • Serology, including nontreponemal (VDRL, RPR) and treponemal tests (FTA-ABS, TPI, TPHA)
Vibrio cholerae
  • Contaminated water and food, especially raw seafood
  • Fluid and electrolyte replacement
  • e.g. doxycycline to shorten duration
  • Preventing fecal contamination of water supplies and food
  • Adequate food preparation
  • Culture on blood or MacConkey agar, enhanced by TCBS
  • Positive oxidase test
Yersinia pestis
  • Fleas from animals
  • Ingestion of animal tissues
  • Respiratory droplets
  • Streptomycin primarily
  • Gentamicin
  • Tetracyclin
  • Supportive therapy for shock
  • Formalin-killed plague vaccine
  • Minimize exposure to rodents and fleas
  • Gram-negative smear
  • If pneumonic, culture from aspirate on MacConkey or blood agar

See also


  1. Fish DN (February 2002). Optimal antimicrobial therapy for sepsis. Am J Health Syst Pharm 59 (Suppl 1): S13–9.
  2. Heise E (1982). Diseases associated with immunosuppression. Environ Health Perspect 43: 9–19.
  3. Saiman L (2004). Microbiology of early CF lung disease. Paediatr Respir Rev 5 (Suppl A): S367–9.
  4. Belland R, Ouellette S, Gieffers J, Byrne G (2004). Chlamydia pneumoniae and atherosclerosis. Cell Microbiol 6 (2): 117–27.
  5. Terri Warren, RN (2010). Is It a Yeast Infection?. URL accessed on 2011-02-23.
  6. Ferris DG, Nyirjesy P, Sobel JD, Soper D, Pavletic A, Litaker MS (March 2002). Over-the-counter antifungal drug misuse associated with patient-diagnosed vulvovaginal candidiasis. Obstetrics and Gynecology 99 (3): 419–425.
  7. Urinary Tract Infections. URL accessed on 2010-02-04.
  8. Adult Health Advisor 2005.4: Bacteria in Urine, No Symptoms (Asymptomatic Bacteriuria). URL accessed on 2007-08-25.
  9. NHS Impetigo
  10. Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; & Mitchell, Richard N. (2007). Robbins Basic Pathology (8th ed.). Saunders Elsevier. pp. 843 ISBN 978-1-4160-2973-1
  11. Template:DorlandsDict
  12. Template:DorlandsDict
  13. Yonath A, Bashan A (2004). Ribosomal crystallography: initiation, peptide bond formation, and amino acid polymerization are hampered by antibiotics. Annu Rev Microbiol 58: 233–51.
  14. Khachatourians GG (November 1998). Agricultural use of antibiotics and the evolution and transfer of antibiotic-resistant bacteria. CMAJ 159 (9): 1129–36.
  15. DOI:10.3389/fmicb.2012.00238
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  16. 16.0 16.1 Unless else specified then ref is: Fisher, Bruce; Harvey, Richard P.; Champe, Pamela C. (2007). Lippincott's Illustrated Reviews: Microbiology (Lippincott's Illustrated Reviews Series), 332–353, Hagerstown, MD: Lippincott Williams & Wilkins.
  17. Institut Pasteur Press Office - Vaccine against shigellosis (bacillary dysentery):a promising clinical trial 15 January 2009. Retrieved on 27 February 2009

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