1. Micrococcaceae Student Lab Division of Laboratory Sciences Michele Jurgensmeier MT(ASCP)

2. General Information Cause human infections Recover from various clinical specimens Found in many places Spread by direct contact Elaborate an inflammatory response Produce pathogenic effects Gram Positive Cocci

3. Family Micrococcaceae Gram Stain: Gram positive cocci Catalase: Positive

4. Gram Stain Gram Positive Cocci in tetrads Micrococcus species

5. Growth Characteristics Aerobic Colony morphology –Smooth, raised, opaque –Pigment Micrococcus species

6. Biochemical Characteristics Non-motile Non-spore forming Glucose oxidizer Modified oxidase + Bacitracin sensitive Furazolidine Resistant Lysostaphin Resistant Micrococcus species

7. Bacitracin Sensitive Zone size > 10 mm around disk Micrococcus species

8. Glucose Oxidizer Tube on left shows glucose oxidation by the presence of yellow color (No oil overlay) Tube on right shows no fermentation of glucose (oil overlay) Micrococcus species

9. Clinical Significance Rarely produces disease Normal flora Opportunistic infection –Immunocompromised Micrococcus species

10. Antibiotic Therapy Test methods and therapeutic guidelines do not exist Susceptible to beta-lactam antimicrobics Micrococcus species

11. Gram Stain Gram Positive Cocci in clusters Staphylococcus species

12. Growth Characteristics Facultative anaerobes Staphylococcus species Colony morphology –Opaque, smooth, circular –Gray-white, white, cream, yellow –Hemolysis S. aureus beta-hemolytic

13. Biochemical Characteristics Non-motile Non-spore forming Glucose fermenter Modified oxidase - Bacitracin resistant Furazolidine sensitive Most are sensitive to Lysostaphin Variable growth in 6.5 % Salt (Salt tolerance) Staphylococcus species

14. Micrococcus Staphylococcus species species Gram positive cocci Catalase = Positive Bacitracin = Sens. Mod. Oxidase = Pos Glucose Oxidizer Gram Positive cocci Catalase = Positive Bacitracin = Sens. Mod. Oxidase = Neg Glucose Fermenter

15. Colony morphology Opaque, smooth Raised colony with smooth border White-gold (cream) in color Beta hemolytic Staphylococcus aureus

16. Biochemical Characteristics Coagulase + Staphylococcus aureus Mannitol salt + DNase +

17. Mechanisms of Pathogenicity Capsule Enzymes –Catalase –Coagulase –Staphylokinase –Hyaluronidase –DNase –Beta-lactamase Toxins –Hemolysin –Leukocidin –Exfoliatin –Enterotoxin TSST-1 Staphylococcus aureus

18. Clinical Significance Staphylococcus aureus

19. Impetigo Scalded Skin Syndrome

20. Antibiotic Therapy Penicillinase (beta-lactamase) Agents resistant to penicillinase –Methicillin –Oxacillin –Nafcillin Methicillin Resistant Staph aureus –Drug of choice - vancomycin Staphylococcus aureus

21. Methicillin Resistant S. aureus “S” & “R” strains coexist “R” strains grow more slowly Growth requirements: –Media with neutral pH –Cooler temperature (30-35° C) –2-4% NaCl –Incubate full 24 hours Staphylococcus aureus

22. Clinical Significance Coagulase Negative Staphylococcus

23. Colony morphology Opaque Smooth, raised Staphylococcus epidermidis Gray- white in color

24. Biochemical Characteristics Coagulase - Staphylococcus epidermidis Mannitol salt - DNase – Novobiocin “S”

25. Mechanisms of Pathogenicity Staphylococcus epidermidis Capsule Extracellular slime substance

26. Clinical Significance Normal flora Subacute bacterial endocarditis Meningitis Bacteremia / Septicemia Wound infections Urinary tract infections Post-operative infections Staphylococcus epidermidis

27. Antibiotic Therapy More resistant than Staph aureus Susceptibility testing done if presumed pathogen Drugs of choice –Methicillin –Vancomycin (if methicillin “R”) Staphylococcus epidermidis

28. Biochemical Characteristics Coagulase - Staphylococcus saprophyticus Mannitol salt variable DNase – Novobiocin “R” (<16 mm)

29. Clinical Significance Urinary tract infections –Cystitis in young women –Frequency - 2 nd to E. coli Staphylococcus saprophyticus

30. Antibiotic Therapy Susceptibility testing not routinely done Drugs of choice –Nitrofurantoin –Trimethoprim/sulfamethoxizole –Fluoroquinolone Lack correlation between in vitro and in vivo response Staphylococcus saprophyticus

31. GPC - Catalase Positive Micrococcaceae Modified oxidase Bacitracin OF Glucose Positive Sensitive Oxidizer Negative Resistant Fermenter Micrococcus species + Coagulase - Staph aureus “R” Novobiocin “S” ProbableS taph sapro Coag neg Staph