(+) coagulase; (+) catalase tests; beta hemolysis
S. aureus
gram + cocci in clusters; most pathogenic
has protein A
S. aureus
common area of colonization of S. aureus
nasopharyngeal mucosa
3 common clinical manifestations of S. aureus infection
Folliculitis
Furuncle
Carbuncle
Superficial inflammation of the hair follicle; small erythematous papules/pustules associated with follicles
Folliculitis
common name boil; painful lump with pus
deeper form of folliculitis; associated with pain
Furuncle
formed when furuncles coalesce; found in thick skin; seen in diabetic patients
carbuncle
also called as acne inversa; disorder of the apocrine gland; common location axilla, mammary and perianal regions.
Hiradenitis suppurativa
yellowish crust on the skin
impetigo
also called as Ritter’s disease or pemphigus neonatorum
Staphylococcal Scalded Skin Syndrome
most aggressive form of S. infection; production of exfolatin by bacteria causes infection
Staphylococcal Scalded Skin Syndrome or Ritter’s disease
S. aureus grows in ________
BAP; MSA
biochemical tests for S. aureus
coagulase and catalase (+)
treatment of S. aureus skin infection
wound cleaning and surgical drainage; Penicillin
if MRSA, vancomycin
common cause of Sore throat; gram positive cocci in pairs; strict parasite; sensitive to bactracin; beta hemolytic
Streptococcus pyogenes
Common reservior of S. pyogenes in humans
nasopharyngeal
mode of transmission of S. pyogenes
Droplet/ Direct
enhance transmission of strep infection
overcrowding, warm climate
non infectious sequelae of Strep infection
Rheumatic heart disease and acute glomerulonephritis
Typical secondary infection in a child with atopic dermatitis
impetigo contagiosa
main character of impetigo, strep infection
yellow crusting
infection of the epidermis which extends to the dermis with characteristic punched out lesions
ecthyma
strep caused deep seated infection of the subcutaneous dermis an emergency case with violaceous discoloration of the skin
necrotizing fascitis
laboratory diagnosis of strep
G (+) cocci in pairs
BAP; b-hemolysis
(+) bacitracin
latex agglutination (Ig monoclonal to C-carbohydrate)
treatment of strep infection
penicillin ; alternative; macrolides, eryhromycin
gram negative aerobic bacilli; oppurtunistic pathogen which secretes pyocyanin, pyoverdin, pyorubin
pseudomonas aeruginosa
biochemical test for P. aeruginosa
oxidase test positive
definitive diagnosis of p. aeruginosa
production of pyocyanin and fluorescein
clinical manifestations of P. aeruginosa
green nail syndrome secondary wound infection hot tub folliculitis burn wound sepsis ecthyma gangrenosum
paronchychial infection that develop in individuals whose hands are infrequently submerged in water
green nail syndrome
occur in patients with decubitus ulcer, eczema and tinea pedis
secondary wound infection
pruritic follicular, maculopapular, vesicular or pustular lesions on any part of the body that was immersed in water
hot tub folliculitis
pseudomonal bacteremia produces well-recognized but uncommon distinctive skin lesions
ecthyma gangrenosum
classic disease associated with Corynebacterium diphtheriae
Diphtheria
Mybacterium marinum
Fish tank granuloma
M. chenolae
skin abscess
caused by a closely related group of fungi which have the ablity to utilize keratin as nutrient source
dermatophytoses
an anthropophilic fungus and is the most common and widely distributed dermatophyte of humans
trichophyton rubrum
Key features of T. rubrum
culture characteristics, microscopic morphology and failure to perforate hair in vitro