Staphylococcal food poisoning (SFP)- Staphylococcus aureus enterotoxins

Staphylococcal food poisoning

Staphylococcal food poisoning (SFP) is one of the most probably occurring food-borne diseases which cause intoxication from the consumption of food containing preformed staphylococcal enterotoxins (SEs). Staphylococcal enterotoxins are mainly produced by Staphylococcus aureus which is enterotoxigenic strains of coagulase and Thermo nuclease (TNase) positive staphylococci. While occasionally SFP causing coagulase-negative staphylococcus species are Staphylococcus intermedius, Staphylococcus hyicus, Staphylococcus lutrae, Staphylococcus agnetis, and Staphylococcus schleiferi subsp. coagulans. Similarly, one of the exceptional cases of TNase negative coagulase-positive staphylococci is Staphylococcus … Read more

Biochemical Test of Staphylococcus epidermidis

Biochemical Test of Staphylococcus epidermidis

Biochemical Test of Staphylococcus epidermidis ­Basic Characteristics Properties (Staphylococcus epidermidis) Capsule Mostly Capsulated Catalase Positive (+ve) Citrate Negative (-ve) Coagulase Negative (-ve) Gas Positive (+ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Positive (+ve) H2S Positive (+ve) Hemolysis Negative (-ve) Motility Negative (-ve) MR (Methyl Red) Negative (-ve) Nitrate Reduction Positive (+ve) Oxidase Negative (-ve) Pigment Negative (-ve) Shape Cocci Urease Positive (+ve) VP (Voges Proskauer) Positive (+ve) Fermentation of Arabinose Negative (-ve) Cellobiose Negative (-ve) DNase Negative (-ve) Dulcitol Negative … Read more

Biochemical Test of Staphylococcus aureus

Biochemical Test of Staphylococcus aureus

Biochemical Test of Staphylococcus aureus ­Basic Characteristics Properties (Staphylococcus aureus) Capsule Non-Capsulated Catalase Positive (+ve) Citrate Positive (+ve) Coagulase Positive (+ve) Gas Negative (-ve) Gelatin Hydrolysis Positive (+ve) Gram Staining Positive (+ve) H2S Negative (-ve) Hemolysis Positive (+ve)- Beta Indole Negative (-ve) Motility Negative (-ve) MR (Methyl Red) Positive (+ve) Nitrate Reduction Positive (+ve) OF (Oxidative-Fermentative) Fermentative Oxidase Negative (-ve) Pigment Mostly Positive (+ve) PYR Negative (-ve) Shape Cocci Spore Non-Sporing Urease Positive (+ve) VP (Voges Proskauer) Positive (+ve) Fermentation … Read more

Staphylococcus saprophyticus- An Overview

Staphylococcus saprophyticus

What is Staphylococcus saprophyticus? Staphylococcus saprophyticus is a Gram-positive, coagulase-negative coccus that is an important part of the group of microorganisms causing urinary tract infections (UTIs), particularly in young sexually active females. Like all Staphylococci, S. saprophyticus is also clustering Gram-positive cocci, nonmotile, non-spore-forming, and facultatively anaerobic. S. saprophyticus is a part of the normal flora in humans that colonizes the areas like the perineum, rectum, urethra, cervix, and gastrointestinal tract. This bacterium is also a common gastrointestinal flora in pigs … Read more

Staphylococcus aureus- An Overview

Staphylococcus aureus

Image Source: ASM and Bacteria in Photos. Habitat of Staphylococcus aureus The natural habitat is mammalian body surfaces. They are normal flora of the skin and mucous membrane. Also present in the nose / the anterior nares. They can also be found in Pharynx. Found in stratified epithelial cells or mucous or serum constituents associated with these cells. Found in skin/nasal passage and axillae of humans. They act as a benign or symbiotic relationship with the hosts. Enterogeneric strains of S. aureus … Read more

Staphylococcus lugdunensis- An Overview

Staphylococcus lugdunensis

What is Staphylococcus lugdunensis? Staphylococcus lugdunensis is a Gram-positive, coagulase-negative coccus that is a part of human normal flora but recently has been associated with various skin and soft tissue infections. S. lugdunensis has a significant pathogenic potential compared with other coagulase-negative staphylococci owing to its various virulence factors. Like all Staphylococci, S. lugdunensis is also clustering Gram-positive cocci, non-motile, non-spore-forming, and facultatively anaerobic. It was first isolated and described by Jean Freney et al. in 1988 from human clinical … Read more

Staphylococcus hominis- An Overview

Staphylococcus hominis

What is Staphylococcus hominis? Staphylococcus hominis is a Gram-positive coagulase-negative member of Staphylococci that exists as a commensal on the human body, especially in the areas with apocrine glands, axillae, and the pubic region. Like most other coagulase-negative Staphylococci, S. hominis is also known to cause various nosocomial or hospital-acquired infections and may occasionally cause infection in patients with abnormally weak immune systems The term ‘hominis’ is derived from the Latin term ‘hominis’ which means humans, and it thus is … Read more

Staphylococcus capitis- An Overview

Staphylococcus capitis

What is Staphylococcus capitis? Staphylococcus capitis is a Gram-positive, coagulase-negative coccus, present as a part of the human normal flora mostly localized in areas around the scalp and face that have been lately associated with bacteria in neonates. Staphylococcus capitis is a coagulase-negative Staphylococci with documented potential for both human disease and nosocomial spread. It is non-motile, non-spore-forming facultatively anaerobic even though the best growth is observed under aerobic conditions. The species name ‘capitis’ is derived from the Latin name … Read more

Coagulase Test- Principle, Procedure, Types, Result, Uses

Coagulase Test

Coagulase Test Definition A coagulase test is a biochemical test that is used to differentiate Staphylococcus aureus from other Staphylococci species like S. epidermidis and S. saprophyticus on the basis of the ability to produce the coagulase enzyme. The coagulase test is an important test that differentiates the species of the genus Staphylococci into two groups; Coagulase positive Staphylococci and Coagulase Negative Staphylococci. The coagulase enzyme acts as a virulence factor in some organisms as it interacts with the fibrinogen … Read more

Staphylococcus epidermidis- An Overview

Staphylococcus epidermidis - An Overview

What is Staphylococcus epidermidis? Staphylococcus epidermidis is a Gram-positive bacterium belonging to the genus Staphylococcus and is the most frequently isolated species from human epithelia. Staphylococci are known as clustering Gram-positive cocci, nonmotile, non-spore-forming facultatively anaerobic that classified into two main groups, coagulase-positive and coagulase-negative. S. epidermidis belongs to the group of coagulase-negative staphylococci (CoNS), which is different from coagulase-positive staphylococci such as S. aureus by lacking the enzyme coagulase. It colonizes the axillae, head, and nares predominantly and is assumed to … Read more