Coccus Tao Chuan-min Tel:

Outline Staphylococcus Streptococcus Enterococcus Neisseria and Branhamella Classification 、 Clinical Significance 、 Microbial Characters 、 Microbial diagnostics

Staphylococcus Gram-positive cocci that occur singly and in pairs, tetrads, and irregular grape-like clusters

Common description Widespread in nature Mainly found living on the skin, skin glands and mucous membranes of mammals and birds Also found in the environment Sometimes found in the mouth, blood, and intestinal, and upper respiratory tracts

Classification Currently composed of 32 species and 15 subspecies Important Staphylococcus S. aureus S. epidermidis S. capitis S. hominis S. saprophyticus Coagulase Coagulase positive Staphylococci Coagulase negative Staphylococci

Clinical significant S. aureus Important pathogen  Enzymes:catalase, coagulase,staphylokinase, et al  Toxin: exotoxin, enterotoxin, et al Community- and hospital acquired infection Acute pyogenic infection  Common infection ： boil 、 cellulitis 、 postoperative wound infections  Serious infection ： bacteremia 、 pneumonia 、 osteomyelitis 、 meningitis ， acute endocarditis, et al

Boils Infection of hair follicles by S. aureus Impetigo School sores; common mostly among children Abscess Osteomyelitis

Food poisoning: enterotoxin Toxic shock syndrome(TSS) ： toxic shock syndrome toxin 1(TSST-1) Scaled skin syndrome

Coagulase negative staphylococcus, CONS Normal flora of human Causing nosocomial infections S. epidermidis  Prosthetic valve endocarditis  Intravascular catheter-related infection  Peritoneal dialysis-related infection  Prosthetic joint infection  Why The increase in the use of prosthetic and indwelling devices Immunocompromised patients in hospitals S. saprophyticus  Urinary tract infection

Microbial Characters Gram positive coccus arranged ： single 、 pairs 、 tetrads, short chains and grape-like clusters Facultatively anaerobe Colonial appearance Color, smooth, entire, heamolytic characters Chemical reaction: active metabolism, fermenting carbohydrates Catalase ： +(differentiates from streptococcus) Coagulase: +/-

Microbial diagnostics procedure specimen Smear and stain culture direct examination colony Smear and stain biochemical serology antibiotic identification identification susceptibility Isolated culture Broth culture

Specimen collection Routine method  Avoid normal flora contamination  Surface swab, pus, blood, spinal fluid, sputum, et al Specimen direct diagnostics Smear and Gram stain report Culture and identification Media selection  Blood agar  Broth  Selective agar

Colonial appearance S. epidermidis Small, smooth, entire, slightly raised, white, nonheamolysis S. aureus Large,smooth,entire, slightly raised, pigment from cream-yellow to orange, β heamolysis

Catalase Staphylococcus produce catalase Convert hydrogen peroxide into water and oxygen (formation of bubbles)

Coagulase production Ability to clot plasma Rapid and economical test Dehydrated rabbit plasma containing EDTA Slide test Bound coagulase ＋ plasma clot(10s) +: S. aureus and S. intermedius Tube test Free coagulase Other: latex agglutination test

Heat-stable nuclease + ： S. aureus, S. schleiferi, S. intermedius and S. carnosus Heat-stable staphylococcal nuclease (thermonuclease[TNase]) Method: metachromatic agar diffusion procedure and DNA- toluidine blue agar Phosphatase activity + ： S. epidermidis, S. aureus, S. schleiferi and S. intermedius

Pyrrolidonyl arylamidase activity (PYR test) principle: bacteria L-pyrrolidonyl-β-naphthylamide β-naphthylamine ＋ N,N-dimethylaminocinnamaldehyde red color

Other Ornithine decarboxylase activity β-galactosidase activity Novobiocin resistance

Antibiotic susceptibilities A class （ routine antibiotic ） oxacillin,penicillin B class （ use mainly antibiotic in clinical ） azithromycin,clindamycin,TMP/SMZ,vacomycin C class （ resistant to A class ） ciprofloxacin,gentamicin,chloramphenicol U class （ bacteria from urine ） norfloxacin, nitrofurantoin

Methecillin resistant Staphylococcus, MRS MRSA 、 MRSE 、 MRSCO Main pathogen in nosocomial infection Resistant to oxacillin resistant ： high resistant heteroresistant ： borderline Two subpopulations coexist: one susceptible and the other resistant

MRS Detection methods The presence of NaCl （ 2 to 4% ） cooler temperatures (30 to 35 ℃ ) prolonged incubation(up to 48h) mecA gene probe PCR

MRS Resistant mechanism chromosome mecA gene mediated, produce low affinity penicillin binding protein(PBP), PBP2’ or PBP2a characters Multidrug-resistant Resistant to all β － lactams Clinical use Vacomycin, teicoplanin, ciprofloxin, TMP-SMZ, et al

Summary Gram stain ＋ colonial appearance Catalase + + S. aureus _ coagulase CONS Attention: MRS