Microbiology Reference Libraries

Lactobacillus acidophilus is a species in the genus Lactobacillus. It is a homo-fermentative species, fermenting sugars into lactic acid, which grows readily at rather low pH values and has an optimum growth temperature of 37 °C. It occurs naturally in the human and animal gastrointestinal tract, mouth, and vagina. Some strains have probiotic characteristics. Strains are commercially used in...

Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose fermenting, facultative anaerobic, rod shaped bacterium found in the normal flora of the mouth, skin, and intestines. It is the most important member of the Klebsiella genus of Enterobacteriaceae. It is naturally occurring in soil and about 30% of strains can fix nitrogen in anaerobic conditions. Hans Christian Gram...

Haemophilus influenzae is a Gram-negative, rod-shaped bacterium first described in 1892 by Richard Pfeiffer during an influenza pandemic. It is generally aerobic but can grow as a facultative anaerobe. H. influenzae was mistakenly considered to be the cause of influenza until 1933 when the flu virology became apparent. It was the first free-living organism to have its entire genome...

Gardnerella is a genus of gram-variable-staining facultative anaerobic bacteria of which G. vaginalis is the only species. It grows as small, circular, convex, gray colonies on chocolate agar. Colistin-oxolinic acid blood agar is a selective medium for G. vaginalis. Bacterial vaginosis results in some women as a result of disruption of the normal vaginal microflora. Lactobacillus population...

Francisella tularensis is a pathogenic species of gram-negative bacteria and the causative agent of tularemia or rabbit fever. It is a facultative intracellular bacterium. It is classified as a Class A agent by the U.S. government due to its ease of spread by aerosol and its high virulence. In 1911 the species was found in ground squirrels in California. There are four subspecies that have...

Escherichia coli is a Gram-negative rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms. Most strains are harmless; however, some such as O157:H7 can cause food poisoning in humans and are often responsible for product recalls. The normal flora of the gut normally contains the harmless strains and often provide K2 to the body. They are not always...

Enterococcus faecalis "“ formerly classified as part of the Group D Streptococcus system "“ is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. It is one of the main constituents of some probiotic food supplements. E. faecalis can cause life-threatening infections in humans. It is frequently found in root canal-treated teeth in...

Corynebacterium diphtheriae is a pathogenic bacterium that causes diphtheria. It was discovered in 1884. There are four subspecies C. diphtheriae mitis, C. diphtheriae intermedius, C. diphtheriae gravis, and C. diphtheriae belfanti. They all are a little bit different in their colonial morphology and biochemical properties such as the ability to metabolize certain nutrients. The diphtheria...

Clostridium tetani is a rod-shaped, anaerobic bacterium of the genus Clostridium. It's a gram-positive and resembles tennis rackets or drumsticks on a gram stain. It can be found as spores in soil and the gastrointestinal tract of animals. It produces a potent biological toxin which is the causative agent of tetanus. Ancient people recognized the relationship between wounds and fatal muscle...

Clostridium perfringens (formerly known as C. welchii) is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. It is always present in nature and is a normal component of decaying vegetation, marine sediment, the intestinal tract of humans, other vertebrates, insects, and soil. It can be a human pathogen and also harmlessly ingested. Commonly it is...