Enterobacteriaceae Cultural Characteristics

Enterobacteriaceae Cultural Characteristics

Image Source: Cole-Parmer Instrument Company. Cultural Characteristics of Citrobacter freundii Citrobacter freundii on Nutrient Agar Smooth, convex, translucent, or opaque grey colored with a shiny surface and entire margin; mucoid or rough colonies occasionally. Citrobacter freundii on Blood Agar Circular, flat, entire red colored colonies. Citrobacter freundii on Mac-Conkey Agar Pink colored after 24 hr … Read more Enterobacteriaceae Cultural Characteristics

Bacterial Sizes, Shapes and Arrangement with Examples

Bacterial Sizes, Shapes and Arrangement with Examples

Bacteria are a type of biological cell that is prokaryotic and unicellular. Due to the lack of a membrane-bound nucleus, these are simpler than other types of living organisms. Although only some of them can be seen by naked eyes while the rest are microscopic, they display a wide range of shape, size, and structure. … Read more Bacterial Sizes, Shapes and Arrangement with Examples

Hemolysis of Streptococci- Types and Examples with Images

Hemolysis of Streptococci- Types and Examples with Images

Introduction A genus Streptococcus is a heterogeneous group of Gram-positive bacteria. Various streptococci are considered as the normal microbial flora of animals and humans, while some species under favorable conditions can also cause diseases ranging from sub-acute infection to acute or even chronic diseases/infections. Streptococci are spherical organisms that grow in chains because of incomplete … Read more Hemolysis of Streptococci- Types and Examples with Images

Gram-positive bacteria- cell wall, examples, diseases, antibiotics

Gram-positive bacteria

What are Gram-positive bacteria? These are bacteria whose classification has been based on their ability to retain the crystal violet dye after a brief wash with alcohol in the differential gram staining. Gram-positive bacteria stain purple while the Gram-negative bacteria stain Pink, after losing the purple color during the alcohol was thus taking up the … Read more Gram-positive bacteria- cell wall, examples, diseases, antibiotics

Gram-negative bacteria- cell wall, examples, diseases, antibiotics

Gram-negative bacteria

What are Gram-negative bacteria? These are bacteria that define the opposite of the gram-positive bacteria in relation to the differential staining technique.  During gram staining, the gram-negative bacteria will lose the crystal violet dye color after a wash with alcohol and take up the pink/red color of the counterstain, safranin. The two classes of bacteria … Read more Gram-negative bacteria- cell wall, examples, diseases, antibiotics

Epsilometer test (E test)

Epsilometer test (E test)

Introduction Epsilometer test (E- test) is defined as the “exponential gradient” method that determines the antimicrobial resistance of the microorganism. It is a cost-effective tool that has been developed to provide a direct quantification of antimicrobial susceptibility of microorganisms. It is a quantitative method that applies both the dilution of antibiotics and the diffusion of … Read more Epsilometer test (E test)

Shiga toxin-producing Escherichia coli (STEC)

Shiga toxin-producing Escherichia coli (STEC)

Shiga toxin-producing Escherichia coli (STEC) The Shiga toxin-producing E. coli (STEC), is also alternatively referred to as verocytotoxin-producing E. coli (VTEC), and enterohemorrhagic E. coli (EHEC). All members of this group are defined by the presence of Shiga toxin 1 (Stx1) or 2 (Stx2). Some but not all EHEC strains are LEE positive and form … Read more Shiga toxin-producing Escherichia coli (STEC)

Enterotoxigenic E. coli (ETEC)

Enterotoxigenic E. coli (ETEC)

Enterotoxigenic E. coli (ETEC) Enterotoxigenic E. coli (ETEC) is defined as containing the E. coli strains that elaborate at least one member of two defined groups of enterotoxins: heat-stable toxin (ST) and heat-stable toxin (LT). Enterotoxigenic Escherichia coli, or ETEC, is thus the name given to a group of E. coli that produces special toxins that stimulate the lining … Read more Enterotoxigenic E. coli (ETEC)

Shigella dysenteriae- Pathogenicity and Clinical Manifestation

Shigella dysenteriae- Pathogenicity and Clinical Manifestation

Shigella dysenteriae- Pathogenicity and Clinical Manifestation Shigella dysenteriae is a species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is extremely pathogenic and causes severe dysentery. Infection with this organism often leads to ulceration of the intestinal epithelium. It is known to produce an exotoxin (Shiga toxin) which disrupts protein synthesis and produces endothelial damage. Figure: … Read more Shigella dysenteriae- Pathogenicity and Clinical Manifestation

Neisseria gonorrhoeae- Laboratory Diagnosis, Treatment, Prevention

Neisseria gonorrhoeae- Laboratory Diagnosis, Treatment, Prevention

Neisseria gonorrhoeae is an obligate human pathogen and is the etiological agent of gonorrhea. In the United States, it is the second most commonly reported communicable disease, with more than 350,000 cases reported annually. Syndromes include cervicitis in women and urethritis, pharyngitis and proctitis in both sexes. If untreated, women may experience severe sequelae of … Read more Neisseria gonorrhoeae- Laboratory Diagnosis, Treatment, Prevention