D. Evaluation.C.Registration.html_________Updated June 98.

Evaluation depends on interpretative reading (L 15,16,18)of the sensitivity pattern and leads to the choice of the most suitable antibiotic or combination of antibiotics.

If resistance depends on a resistance mechanism, the demonstration of this leads to the reply:

R, resistant and if not: S, sensitive. I, intermediate, does not occur. Examples are resistance to penicillin and methicillin in Staphylococcus. F.species.html

Resistance to B-lactam antibiotics in the Enterobacteriaceæ requires information about species as well as the results of sensitivity testing with different B-lactam antibiotics as specified in table

D1.B-lactam.497.html . Most useful are at present in Denmark ampicillin, plus a carboxi -penicillin,i.e. carbenicillin, plus a weak cephalosporin, cephalothin or cefpodoxime (L 23). This means in all cases that isolates belonging to the groups named in table D1 divided after chromosomal or episomal B-lactamases can be reported as S or R. See F.species.html

One exception is E. coli: some isolates without B-lactamases may have ampicillin MIC >4 mg/l and should be reported as I. See also D. Surveillance.

 

Table D0. Antibiotics useful as markers, m, or as therapeutics, t.

Antibiotic

Gram positive

Coccus rod

Gram negative

Coccus rod

Anaerobe

A:

penicillin G

ampicillin

carbenicillin

piperacillin

mecillinam

cefalothin

cefuroxim

cefotaxim

ceftazidime

aztreonam

streptomycin

gentamicin

tobramycin

netilmicin

kanamycin

vancomycin

teicoplanin

polymyxin

tetracycline

chloramphenicol

erythromycin

nitrofurantoin

sulphonamide

trimetoprim

fluoroquinolones

 

m,t_____t

t_______t

m______m

m______-

m______-

t_______m,t

t_______t

-_______m

m______-

m______-

m,t_____t

m,t_____t

m,t_____t

m,t_____t

-______-

m,t_____t

m,t_____-

m______m

m______-

m______-

m,t_____t

t_______-

m______-

-_______-

-_______-

 

t_______t

-_______m,t

-_______m

-_______t

-_______m,t

-_______m

t________t

t________t

-________m,t

m_______m,t

-________m,t

-________m,t

-________m,t

-________m,t

-________m

-________m

-________m

m_______m

-________m,t

-________m,t

-________m

-________t

t________m,t

m_______m,t

t________m,t

 

m,t

-

-

m,t

-

-

-

t

-

-

-

-

-

-

-

-

-

-

t

t

t

-

-

-

-

 

B:

methicillin

carbapenemes

clindamycin

fucidin

rifampicin

metronidazole

 

m,t______-

t________-

t________-

t________-

t________-

-________-

 

-________-

-________m,t

-________-

-________-

-________-

-________-

 

m,t

t

t

-

-

t

Markers only:

optochin

oxacillin

novobiocin

nalidixan

 

m_______-

m_______-

m_______-

-________-

 

-________-

-________-

-________-

m_______m

 

-

-

-

-

A: For primary sensitivity testing. B: After initial identification

See also http://www.microbes-edu.org and http://www.microbes-edu.com