Microbiology Reference Libraries

Treponema pallidum is a species of spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta and yaws. Since the organism has a waxy coat around it won't accept the gram stain. The Dieterle stain is used to detect the bacterium. It is detected by serology, including nontreponemal, Rapid plasma regain, and treponemal antibody tests. It is a motile...

Streptococcus salivarius is a species of spherical, Gram-positive bacteria which colonize the mouth and upper respiratory tract of humans a few hours after birth, making further exposure to the bacteria harmless. The bacterium is an opportunistic pathogen which rarely makes its way into the bloodstream where it is associated with septicemia cases in people with neutropenia. It has different...

Streptococcus pyogenes is a spherical, Gram-positive bacterium is the cause of Group A streptococcal infections. It displays streptococcal group A antigen on its cell wall. When it is cultured on blood agar plates it produces large zones of beta-hemolysis. They are catalase-negative and in ideal conditions it has an incubation period of about 1-3 days. It is an infrequent part of the skin...

Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, bile-soluble aerotolerant, anaerobic member of the genus Streptococcus. It was recognized as a major cause of pneumonia in the late 19th century and is thus the subject of many humoral immunity studies. It causes many other types of pneumococcal infections other than pneumonia including acute sinusitis, otitis...

Streptococcus oralis is a Gram positive bacterium that grows characteristically in chains. On a Wilkins-Chalgren agar plate it will form slam white colonies. It is classified as a member of the streptococcus mitis group and is found in high numbers in the oral cavity. S. oralis produce neuraminidase and an IgA protease and cannot bind α-amylase.

Streptococcus mutans is a Gram-positive cocci, Facultative anaerobic bacterium commonly found in the human oral cavity and is a significant contributor to tooth decay. J Kilian Clarke first described the microbe in 1924. The first colonizers of the tooth surface are mainly Neisseria spp. and streptococci, including S. mutans. The pioneer species changes the local environmental conditions...

Enterococcus is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. It is a main constituent of some probiotic food supplements. E. faecalis can cause life-threatening infections in humans, especially in the nosocomial environment, where the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity....

Staphylococcus epidermidis is one of thirty-three known species belonging to the genus Staphylococcus. It is part of our skin flora and can also be found in the mucous membranes and in animals. It is the most common species found in laboratory test due to contamination. It is not usually pathogenic; however, patients with a compromised immune system often risk infection. Infections can be...

Staphylococcus aureus is a facultative anaerobic gram-positive coccus, and is the most common cause of staph infections. It is commonly part of the skin flora found in the nose and on skin. Around 20% of the human population is long-term carriers. It gets its golden color due to its carotenoid pigment staphyloxanthin. The pigment acts as a virulence factor with an antioxidant action that allows...

Serratia marcescens is a species of Gram-negative, rod-shaped bacterium in the family Enterobacteriaceae. S. marcescens is involved in nosocomial infections particularly catheter-associated bacteremia. It is commonly found in respiratory and urinarty tracts of hospitalized adults and often in the gastrointestinal system of children. It is commonly found growing in bathrooms due to its...