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. 

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 dependent on living in animals.

Streptococcus sobrinus

Structure and Physiology

This bacteria is a Gram-positive, sphere-shaped, anaerobic microorganism that is pathogenic within humans.

Transmission and Disease

Found 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. The high consumption of these sugars may facilitate the growth of these organisms and because of this, may be one of the of the onsets of early childhood tooth decay.

Micrococcus luteus

Structure and Physiology

This bacteria is Gram-positive, spherical, and an obligate aerobe. M. luteus is part of the normal flora of the human skin.

Transmission and Disease

M. luteus is rarely found to be responsible for infections. Only those with compromised immune systems are thought to be susceptible to an infection.

Streptococcus pneumoniae

Structure and Physiology

This bacteria is Gram-positive, aerotolerant, and spherical-shaped. S. pneumonia is part of the normally occurring flora of the upper respiratory tract.

Transmission and Disease

S. pneumoniae can be responsible for numerous infections including pneumonia, bacteremia, and meningitis.

Disinfection

S. pneumoniae has exhibited susceptibility to several antimicrobial products and is moderately easy to disinfect.

Notes

References

Staphylococcus epidermidis (MRSE)

Structure and Physiology

This bacteria is a Gram-positive, cocci-shaped, facultative anaerobe which is resistant to the penicillin-derivative antibiotic methicillin. S. epidermidis is part of normal human bacterial flora and is mostly located on skin.

Transmission and Disease

 It is an opportunistic and pathogenic; infections caused by this bacteria can be very difficult to treat.

Disinfection

Most Staphylococcus species are hardy microorganisms capable of surviving on surfaces and under dry conditions.

Notes

Staphylococcus epidermidis

Structure and Physiology

This bacteria is a Gram-positive, cocci-shaped, facultative anaerobe. S. epidermidis is part of the human bacterial flora, mostly located on skin.

Transmission and Disease

It is not usually pathogenic; however, antibiotic resistant strains have evolved.

Disinfection

Most Staphylococcus species are a hardy microorganisms capable of surviving on surfaces and under dry conditions. This bacteria, specifically, is regularly used in quality control, media testing, and pharmaceutical/personal care products testing.

Staphylococcus aureus (MRSA)

Structure and Physiology

Methicillin-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, nafcillin, oxacillin, and cephalosporins. Resistance does not increase the virulence of the microbe but does make it more difficult to treat.

Enterococcus faecalis (VRE)

Structure and Physiology

Enterococcus 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 clinical trials and have shown to be resistant to vancomycin and teicoplanin. The current treatment in the U.S for VRE is linezolid.

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 of 1-2 mm. E. faecium can survive for long periods of time inside hospital, sewage, and soil.