Which is false regarding gram-positive cocci?
Ans. (c) Most enterococci are sensitive to penicillin Unlike streptococci, enterococci are not reliably killed by penicillin or ampicillin alone at concentration achieved clinically in the blood or tissues. Antimicrobial susceptibility testing should be performed routinely on enterococcal isolates. Enterococci resistance to penicillin is two mechanism: Penillin Resistance Penicilase production Altered penicillin binding protein Seen in E. faecalis Common in E. faecum Vancomycin, ampicillin/sulbactam, amoxicillin/clavulanate. Vancomycin plus gentamycin is usedimipenem may be used in combination with gentamycin Vancomycin plus gentamycin is used Other options Option 'a' Staph. saprophyticus specially causes UTI in sexually active young women. Option 'b' Micrococci are catalase and oxidase positive Gr +ve cocci. They are strict aerobes and are non-pathogenic. Micrococci are differentiated from Staphylococci by Hugh and Deifson oxidation fermentation test in which micro- * cocci shows oxidative pattern while staphylococci show fermentative pattern. Anaerobic Cocci Features Gram +ve Gram --ye Organism Peptostreptococci Intestine, vagina and mouth Veillonellae Inhabitation Puerperal sepsis Mouth, intestine and genital tract Diseases Visceral abscess No disease is identified till now. UTl, wound infection Gangrenousapendicitis Treatment Sensitive to penicillin, chloramphenicol and metronidazole
Staph. saprophyticus causes UTI in females
Micrococci are oxidase positive
Most enterococci are sensitive to penicillin
Pneumococci are capsulated