Bacteria

Staphylococcus hominis

STRUCTURE AND PHYSIOLOGY S.hominisis a facultatively anaerobic, Gram-positive cocci generally found on human and animal skin, typically preferring more moist areas such as the axillae and pubic regions. S. hominis produces thioalcohol compounds, which contribute to body odor. TRANSMISSION AND DISEASE Though usually a harmless commensal microorganism, S. hominis can cause illness...

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Micrococcus yunnanensis

STRUCTURE AND PHYSIOLOGY M. yunnanensis is a Gram-positive, aerobic, non-endospore forming cocci. This nonmotile bacterium is found in the roots of the plant, Polyspora axillaris. TRANSMISSION AND DISEASE M. yunnanensis is not generally a pathogenic microorganism and has only been noted as an opportunistic pathogen with immunocompromised people. DISINFECTION As a non-spore-forming bacterium, M....

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Klebsiella oxytoca

STRUCTURE AND PHYSIOLOGY K. oxytoca is a Gram-negative, rod-shaped, facultatively anaerobic bacterium with a bi-membrane structure. Unlike its relative K. pneumoniae, K. oxytoca is indole-positive (ability to convert tryptophan into indole) and can perform lactose fermentation for metabolism. It is a naturally occurring bacterium in soil, and some strains can...

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Bordetella bronchiseptica

STRUCTURE AND PHYSIOLOGY B. bronchiseptica is a Gram-negative, aerobic, non-endospore forming coccobacillus. This bacterium is motile and oxidase and catalase positive.  TRANSMISSION AND DISEASE The pili of B. bronchiseptica attach to the ciliated epithelium of the respiratory tract. Although a primary pathogen for a wide range of animals, B. bronchiseptica, has been...

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Vibrio cholerae

STRUCTURE AND PHYSIOLOGY Vibrio cholerae is a Gram-negative, comma-shaped, highly motile, facultative anaerobic bacterium that has the ability to survive with or without oxygen. Humans are the only natural host for V. cholerae, but the bacterium can also live freely in fresh or salt water. TRANSMISSION AND DISEASE Cholera is a highly...

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Vibrio fischeri

STRUCTURE AND PHYSIOLOGY Vibrio fischeri is a Gram-negative, motile, rod-shaped bacterium that possesses the ability to produce light (bioluminescence) at high cell densities. The marine bacterium can live both as a free organism or as a symbiont for various marine fish and squids, particularly the Hawaiian bobtail squid. TRANSMISSION AND DISEASE Although...

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Gardnerella vaginalis

STRUCTURE AND PHYSIOLOGY Gardnerella vaginalis is a non-spore-forming, coccobacillary (intermediate shape between cocci and bacilli), non-motile bacterium. This microorganism possesses a very thin Gram-positive wall that can appear as either Gram-positive or Gram-negative when stained. G. vaginalis is a facultative anaerobe and is often found to proliferate with other anaerobic...

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Streptococcus mutans

STRUCTURE AND PHYSIOLOGY Streptococcus mutans is a Gram-positive, spherical, facultatively anaerobic bacterium found in the human oral cavity. This microorganism thrives in acidic environments and is known to form biofilms. TRANSMISSION AND DISEASE S. mutans is commonly associated with oral disease and tooth decay. By metabolizing sucrose to lactic acid, S. mutans...

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Shigella sonnei

STRUCTURE AND PHYSIOLOGY Shigella sonnei is a Gram-negative, rod-shaped, nonmotile, non-spore-forming bacterium and has historically been responsible for causing dysentery. S. sonnei is highly clonal (genetically identical cells), and a selective group of lineages is found worldwide. TRANSMISSION AND DISEASE S. sonnei causes the disease shigellosis, an intestinal infection that is spread...

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Proteus mirabilis

STRUCTURE AND PHYSIOLOGY Proteus mirabilis is a Gram-negative, rod-shaped, motile bacterium that produces high levels of urease, a protein that hydrolyzes urea to ammonia. P. mirabilis can be detected in the lab by its unique characteristic to swarm when grown on agar plates. Additionally, this bacterium gives off a strong...

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Porphyromonas gingivalis

STRUCTURE AND PHYSIOLOGY Porphyromonas gingivalis is a Gram-negative, rod-shaped, non-motile bacterium found in the human oral cavity. It is able to bind to host cells as well as with other bacteria to form a biofilm. TRANSMISSION AND DISEASE P. gingivalis secretes various potential virulence factors such as proteins that cause damage to...

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Haemophilus influenzae

STRUCTURE AND PHYSIOLOGY Haemophilus influenzae is a Gram-negative, coccobacillary (intermediate shape between cocci and bacilli), facultative anaerobic pathogenic bacterium. H. influenzae is capnophilic, meaning it thrives in environments with high levels of carbon dioxide. TRANSMISSION AND DISEASE While H. influenzae was believed to cause of influenza until 1933, this species of bacteria...

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Campylobacter jejuni

STRUCTURE AND PHYSIOLOGY Campylobacter comes from the Greek word meaning “curved rod”. Campylobacter jejuni is a helical-shaped, non-spore-forming, Gram-negative, nonfermenting motile bacteria with a single flagellum at one or both sides. C. jejuni is microaerophilic and can survive on low amounts of oxygen. When it is exposed to atmospheric oxygen,...

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Bacteroides fragilis

STRUCTURE AND PHYSIOLOGY Bacteroides fragilis is a Gram-negative, rod-shaped, non-motile bacterium found in the human colon. B. fragilis is an aerotolerant anaerobic bacteria, which allows it to survive in environments with low levels of oxygen. Maintaining a generally beneficial relationship with the host when retained in the gut, B. fragilis...

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Salmonella typhii

STRUCTURE AND PHYSIOLOGY A subspecies of S. enterica, Salmonella typhii is motile, Gram-negative, rod-shaped bacteria. The flagella present on this microorganism allow it to evade the host immune system, increasing its virulence. TRANSMISSION AND DISEASE The causative agent of typhoid fever, S. typhii is rare in developed countries, though still prevalent in...

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Staphylococcus saprophyticus

STRUCTURE AND PHYSIOLOGY S. saprophyticus is a gram-positive, coccoid, coagulase-negative, non-hemolytic bacteria that is commonly a part of the human microflora in the perineum, rectum, urethra, cervix, and gastrointestinal tract. TRANSMISSION AND DISEASE Other than E. coli, S. saprophyticus is one of the most common causative agents in uncomplicated Urinary Tract Infections...

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Staphylococcus intermedius

STRUCTURE AND PHYSIOLOGY S. intermedius is a gram-positive, coccoid, coagulase-positive bacteria that is commonly found as part of the skin and mucosal microflora of many different animals such as dogs, cats, and pigeons. It has been commonly misidentified as S. aureus in the past due to its nature as coagulase-positive. TRANSMISSION...

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Klebsiella aerogenes

STRUCTURE AND PHYSIOLOGY K. aerogenesis a gram-negative, rod-shaped, motile bacterium common to the gastrointestinal tract of humans. It is generally not pathogenic in healthy individuals. K. aerogenes was originally classified as Enterobacter aerogenes until its recent reclassification. TRANSMISSION AND DISEASE These bacteria can cause illness, such as sepsis, in hospital settings or...

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Pseudomonas fluorescens

STRUCTURE AND PHYSIOLOGY P. fluorescens is a gram-negative, rod-shaped bacterium that is found in soil, plants, and water. This microorganism is commonly found in the rhizosphere of plants where it produces antibiotics against other soil-borne plant pathogens as well as promotes overall plant growth and health. TRANSMISSION AND DISEASE P. fluorescens does...

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Pseudomonas aeruginosa

STRUCTURE AND PHYSIOLOGY P. aeruginosais a gram-negative, rod-shaped, strict anaerobe that is ubiquitous in the environment as it is found in humans, animals, and plants as well as soil and water. It is capable of surviving in low oxygen environments provided the right conditions and is known to form persistent...

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Pluralibacter gergoviae

STRUCTURE AND PHYSIOLOGY P. gergoviaeis a gram-negative, rod-shaped, facultative anaerobe that can be found in some plants, insects, and spring water. TRANSMISSION AND DISEASE It is considered an uncommon human pathogen associated with nosocomial infections in immunocompromised individuals. Risk factors include long hospital stays, use of steroids or antimicrobial agents, foreign devices,...

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Deinococcus radiodurans

STRUCTURE AND PHYSIOLOGY Deinococcus radiodurans is a Gram-positive, non-sporulating, aerobic, cocci-shaped bacterium. To the naked eye, it often has a red or pink pigment. Under a microscope, it forms visible tetrads (groups of four cells). TRANSMISSION AND DISEASE This microorganism has not been shown to cause disease in humans. UNIQUE OR INTERESTING FACT D....

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Pasteurella multocida

STRUCTURE AND PHYSIOLOGY Pasteurella multocida is a Gram-negative, coccobacillus, aerobic bacterium. It is oxidase and catalase positive. TRANSMISSION AND DISEASE Pasteurella multocida is the most common cause of soft tissue infections following a bite or scratch from a domestic pet. The bacteria enter the wound at the time of injury and can...

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Elizabethkingia meningosepticca

STRUCTURE AND PHYSIOLOGY Elizabethkingia meningosepticca is a Gram-negative slightly curved rod-shaped bacterium. This organism produces large, smooth colonies on blood and chocolate agars within 24 hours. The microorganism is found worldwide in soil, river water, and reservoirs. TRANSMISSION AND DISEASE E.meningosepticca can cause meningitis in newborns and immune-compromised individuals. However, outbreaks are...

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Geobacillus stearothermophilus

STRUCTURE AND PHYSIOLOGY Geobacillus stearothermophilus is a thermophilic, aerobic bacterium that can form biofilms and heat-resistant spores. Gram stains as Gram-positive rods. TRANSMISSION AND DISEASE There is no public health-related significance. However, due to its thermophilic nature, this organism can be found in dairy plants and can form biofilms on stainless steel...

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Rhizobium radiobacter

STRUCTURE AND PHYSIOLOGY Rhizobium radiobacter is an aerobic, gram-negative, bacilli found in soil worldwide. Colonies are typically circular, convex, semi-translucent, and raised on yeast-mannitol-mineral salts agar. TRANSMISSION AND DISEASE Rhizobium radiobacter is a plant pathogen that rarely affects humans who are not immunocompromised. In plants, Rhizobium radiobacter can cause Crown Gall Disease...

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Stachybotrys chartarum

STRUCTURE AND PHYSIOLOGY Stachybotrys chartarum is a slow-growing but hardy mold that is most often found in cellulose-rich building materials in damp or water-damaged buildings. TRANSMISSION AND DISEASE The spores of Stachybotrys chartarum are only released when the mold is mechanically disturbed, especially when wet. Health problems related to this mold have...

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Staphylococcus haemolyticus

STRUCTURE AND PHYSIOLOGY Staphylococcus haemolyticus is a Gram-positive, coagulase-negative facultative anaerobe. Cells are typically coccus-shaped. Colonies are circular, raised, smooth with smooth margins, and white in color. TRANSMISSION AND DISEASE Staphylococcus haemolyticus is an opportunistic pathogen causing localized or systemic infections. Infections of Staphylococcus haemolyticus are often associated with the insertion of...

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Clostridium septicum

STRUCTURE AND PHYSIOLOGY Clostridium septicum is a large, motile, Gram-positive, anaerobic bacillus found in the normal gut flora of humans and other animals. Clostridium septicum is a motile, spore-forming pathogen commonly isolated from the intestinal flora of humans TRANSMISSION AND DISEASE Clostridium septicum is more virulent than Clostridium perfringens and can cause...

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Dekkera bruxellensis

STRUCTURE AND PHYSIOLOGY Dekkera bruxellensis is a facultative anaerobe with a low growth rate. Cream-colored, dull and rough looking colonies have been observed on malt extract agar. TRANSMISSION AND DISEASE Dekkera bruxellensis is often spread through wine production facilities by contaminated equipment or by fruit flies. Dekkera bruxellensis occurs in fermented foods....

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Fusobacterium necrophorum

STRUCTURE AND PHYSIOLOGY: Fusobacterium necrophorum is a rod-shaped, gram-negative bacteria commonly found in the gastrointestinal tract of humans and other animals. TRANSMISSION AND DISEASE Fusobacterium necrophorum is transmitted via mucous membrane contact and contact with infected body fluids. Fusobacterium necrophorum can cause sore throat, peritonsillar abscesses, meningitis, thrombosis, and infection of the...

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Mycobacterium chimera

STRUCTURE AND PHYSIOLOGY Mycobacterium chimera is classified as a non-tuberculosis Mycobacterium that is a member of the Mycobacterium avium complex (MAC). As a member of MAC, Mycobacterium chimera is characterized as gram-positive, non-motile, and acid-fast-positive bacteria. TRANSMISSION AND DISEASE Mycobacterium chimera is an opportunistic pathogen responsible for respiratory infection mainly in immunocompromised...

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Pseudomonas putida

STRUCTURE AND PHYSIOLOGY Pseudomonas putida is a rod-shaped, aerobic bacteria with multiple flagella typically found in the soil and moist environments. TRANSMISSION AND DISEASE Pseudomonas putida is an occasional cause of catheter-related bacteremia as well as urinary tract infections, neonatal sepsis and war wounds but is generally considered non-pathogenic in non-immunocompromised individuals. UNIQUE...

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Corynebacterium xerosis

Corynebacterium xerosis

Structure and PhysiologyThis bacteria is a Gram positive, rod shaped aerobe. C. xerosis is referred to as a diptheriod because of its relation to C. diptheriae, the bacterium which causes diptheria.Transmission and DiseaseMostly inocuous, C. xerosis is commonly found on human skin and has been known to cause opportunistic...

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Mycobacterium terrae

Structure and Physiology Mycobacterium terrae is an aerobic, nonmotile, rod shaped, acid-fast Gram-positive bacterium.  A distinguishing characteristic of mycobacterium is that the cell wall is thicker than many other bacterium. M. terrae is a slow growing species of Mycobacterium and is sometimes referred to as the “radish bacillus” because it...

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Bacillus subtilis

Bacillus subtilis

Structure and Physiology Bacillus subtilis is a spore forming, motile, rod-shaped, Gram-positive, facultative aerobe. It is mostly found in soil and vegetation with an optimal growth temperature from 25-35 degrees Celsius. B. subtilis has the ability to produce and secrete antibiotics. The genomic structure of this microorganism contains five signal...

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Staphylococcus aureus

Staphylococcus aureus

Structure and PhysiologyStaphylococcus aureus is a Gram-positive, coccal-shaped, facultative anaerobic bacterium. During binary fission, the two daughter cells that are produced do not completely separate. Incomplete separations of the cells result in the cluster formation. S. aureus is a catalase-positive bacterium that is able to combat the electronegative oxidizing...

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Klebsiella pneumoniae

Klebsiella pneumoniae

Structure and Physiology Klebsiella pneumoniae is a Gram-negative, rod-shaped, facultative anaerobic bacterium. It is encapsulated and undergoes lactose fermentation for metabolic purposes when conditions allow. This nonmotile bacterium is found in humans within the normal flora of the mouth, skin, and intestines. It is a naturally occurring bacterium in the soil...

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Listeria monocytogenes

Listeria monocytogenes

Structure and PhysiologyListeria monocytogenes is a Gram-positive, rod-shaped, motile, facultative anaerobic bacterium that has the ability to survive with or without oxygen. Contrary to most non-spore forming bacterium, L. monocytogenes can survive the effects of freezing, drying, high pH, and high temperatures. It has the ability to grow at...

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Bacillus cereus

Bacillus cereus

Structure and PhysiologyBacillus cereus is a Gram-positive, rod-shaped, endopore-forming facultative aerobe bacterium related to Bacillus anthracis and Bacillus thuringiensis.Transmission and DiseaseAlthough B. cereus is commonly associated with food-borne illnesses, this microbe can also be responsible for several local and systemic infections.DisinfectionDue to this bacterium's ability to sporulate, B. cereus...

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Salmonella enterica

Salmonella enterica

Structure and Physiology Salmonella enterica is a Gram-negative, rod-shaped, facultative anaerobic bacterium that is common to all parts of the world. S. enterica contains flagella that are used for locomotion and a sensory organelle to measure the chemical nature and temperature of the extracellular space. A characteristic of this bacterium...

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Streptococcus pyogenes

Streptococcus pyogenes

Structure and PhysiologyStreptococcus pyogenes is a Gram-positive, spherical, and facultative anaerobic bacterium. Similar in cellular morphology to Staphylococcus species, this species of bacteria grows in long chains versus the grape-like clusters observed as Staphylococcus. Known as the flesh eating bacteria, S. pyogenes is the most pathogenic bacterium in the...

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Escherichia coli

Escherichia coli

Structure and PhysiologyEscherichia coli is a Gram-negative, rod-shaped, facultative anaerobic bacterium that is commonly found in the gastrointestinal tract of warm-blooded animals. Although most serotypes of this organism are harmless inhabitants of the intestinal flora, there are pathogenic strains of E. coli that produce toxins which cause illness in...

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Legionella pneumophila

Legionella pneumophila

Structure and Physiology This bacteria is a Gram-negative, flagellated aerobe that is nonencapsulated and pleomorphic. L. pneumophila is a facultative, intracellular parasite, meaning that while able to survive and replicate outside of a host, the natural resevoir of this microorganism is inside of free-living, ubiquitous ameoba, where it uses the host...

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Acinetobacter baumannii

Acinetobacter baumannii

Structure and Phisiology This bacteria is a Gram-negative, rod-shaped aerobe. A. baumannii can be responsible for infections such as pneumonia and septicemia in immunodeficient patients. The natural reservoir of this organism remains to be determined. These are among a class of bacteria that are "naturally transformable" - meaning that the...

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Enterococcus faecium

Structure and Physiology Enterococcus faecium is a Gram-positive, coccal shaped, facultative anaerobic bacterium that can occur in pairs or chains. Its natural habitat includes the gastrointestinal tract, oral cavity, and vaginal tract of a wide variety of animals. The colonies that are produced appear wet and have an average size...

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Enterobacter aerogenes

Enterobacter aerogenes

Structure and Physiology This bacteria is Gram-negative, rod-shaped, and radially surrounded by flagellum. It can be found in dairy products, soil, and the gastrointestinal tract of animals. E. aerogenes is closely related to a wide range of other common microorganisms including Escherichia, Klebsiella, Shigella, and Serratia.    Transmission and Disease This bacteria can be involved in...

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Enterobacter cloacae

Enterobacter cloacae

Structure and Physiology This bacteria is a Gram-negative, rod shaped, facultative anaerobe commonly found in the gastrointestinal tract of humans. It is not usually a primary pathogen although it is sometimes associated with urinary and respiratory tract infection. Transmission and Disease Enterobacter cloacae can be acquired through the skin, urinary tract, or gastrointestinal...

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Streptococcus pneumoniae

Streptococcus pneumoniae

Structure and PhysiologyThis bacteria is Gram-positive, aerotolerant, and spherical-shaped. S. pneumonia is part of the normally occurring flora of the upper respiratory tract.Transmission and DiseaseS. pneumoniae can be responsible for numerous infections including pneumonia, bacteremia, and meningitis.DisinfectionS. pneumoniae has exhibited susceptibility to several antimicrobial products and is moderately easy...

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Staphylococcus epidermidis

Staphylococcus epidermidis

Structure and PhysiologyThis bacteria is a Gram-positive, cocci-shaped, facultative anaerobe. S. epidermidis is part of the human bacterial flora, mostly located on skin.Transmission and DiseaseIt is not usually pathogenic; however, antibiotic resistant strains have evolved.DisinfectionMost Staphylococcus species are a hardy microorganisms capable of surviving on surfaces and under dry...

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Staphylococcus aureus (MRSA)

Staphylococcus aureus (MRSA)

Structure and PhysiologyMethicillin-resistant Staphylococcus aureus (MRSA) is a Gram-positive, coccal-shaped, facultative anaerobic bacterium that is responsible for many difficult to treat infections. MRSA is any strain of Staphylococcus aureus that has developed a resistance to beta-lactam antibiotics through the process of natural selection. Beta-lactam antibiotics include penicillin, methicillin, dicloxacillin,...

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Enterococcus faecalis (VRE)

Enterococcus faecalis (VRE)

Structure and PhysiologyEnterococcus faecalis is a Gram-positive, nonmotile, facultative anaerobic microbe.  Vancomycin Resistant Enterococcus (VRE) are strains that are resistant to the antibiotic vancomycin. There are six different types of vancomycin resistance shown by Enterococcus: Van-A, Van-B, Van-C, Van-D, Van-D, Van-E, Van-F. Van-A, Van-B, Van-C have been tested in...

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Micrococcus luteus

Micrococcus luteus

Structure and PhysiologyThis bacteria is Gram-positive, spherical, and an obligate aerobe. M. luteus is part of the normal flora of the human skin.Transmission and DiseaseM. luteus is rarely found to be responsible for infections. Only those with compromised immune systems are thought to be susceptible to an infection.DisinfectionM. luteus...

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S. marcescens

Serratia marcescens

Structure and Physiology This bacteria is a Gram-negative, rod-shaped, facultative anaerobe that has been classified as an opportunistic pathogen for immunocompromised individuals. This bacteria can be commonly found in damp environments like bathrooms, where it manifests as a pink-orange film due to a reddish-orange pigment called prodigiosin. Transmission and Disease S. marcescens can...

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Burkholderia cepacia

Burkholderia cepacia

Structure and Physiology This bacteria is Gram-negative, rod shaped, and capable of growth in a variety of environments including soil, water, animals, and plants. B. cepacia is closely related to Pseudomonas spp. and exhibits several similar morphological characteristics. Transmission and Disease Typically identified as a plant and human pathogen, it is known...

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Propionibacterium acnes

Propionibacterium acnes

Structure and Physiology This bacteria is a Gram-positive, rod shaped, aerotolerant anaerobe. Slow growing and aerotolerant, this microorganism is part of the normal flora of healthy human skin, living deep inside pores and follicles.  Transmission and Disease Excess sebum (oil) production due to overactive sebaceous glands or blockage of a follicle can...

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M. smegmatis

Mycobacterium smegmatis

Structure and Physiology This bacteria is an acid-fast, bacillus-shaped, aerobic microorganism that is commonly used a surrogate model for M. tuberculosis and is found in soil, plants, and water. Transmission and Disease M. smegmatis is non-pathogenic to humans except in rare cases, and is considered saprophytic. Unlike other pathogenic Mycobacterium, M. smegmatis isn't...

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M. bovis

Mycobacterium bovis BCG

Structure and Physiology This bacterium is a rod shaped, slow growing, aerobic bacterium. As this microbe is acid-fast, staining is done using the Ziehl-Neelson stain rather than gram staining.  Transmission and Disease Mycobacterium bovis BCG is the causative agent of tuberculosis in cattle and a close relative (>99.95% identical at the nucleotide...

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Streptococcus sobrinus

Streptococcus sobrinus

Structure and PhysiologyThis bacteria is a Gram-positive, sphere-shaped, anaerobic microorganism that is pathogenic within humans.Transmission and DiseaseFound in the human mouth in the form of biofilm and plaque, S. sobrinus thrives in the slightly acidic environment of the oral cavity because it metabolizes food sugars passing through the mouth....

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N. gonorrhoeae

Neiserria gonorrhoeae

Structure and Physiology This bacteria is a Gram-negative diplococci. Transmission and Disease Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection gonorrhea. This bacteria is capable of transformation and conjugation to spread genes and mutations. This makes it difficult for the immune system to recognize and an area of interest...

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Bordetella pertussis

Bordetella pertussis

Structure and Physiology This bacterium is a Gram-negative, non-motile, coccobacillus aerobe. Transmission and Disease B. pertussis is the organism responsible for whooping cough and is transmitted via airborne droplets contaminated with the organism, such as those produced by the act of coughing itself.  Once adhered to the surface of the thoat, B. pertussis releases a...

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