**7. Susceptibility testing of enterococci**

CLSI 31st Edition (2021) of performance standards for antimicrobial susceptibility testing, sets down the following procedure for reporting of Enterococcal susceptibility testing [14].

Penicillin can act as a surrogate for Ampicillin, Amoxycillin and all the Betalactam-lactamase combinations as long as beta lactamase is not produced by the strain, however, Ampicillin cannot be a surrogate for Penicillin.

	- a.Ampicillin has to be combined with an aminoglycoside to which there is no high level resistance (HLAR- as per procedure spelt out in CLSI M100).
	- b.If Ampicillin MIC is >16 μg/ml and less than 64 μg/ml and the strain is susceptible to Gentamicin (noHLAR), this combination will still be effective, if Ampicillin is given in high dose.
	- c.Combination is not effective if strain is resistant to either Ampicillin or Gentamicin.
	- d.HLAR test has to be done for Gentamicin and Streptomycin separately. Gentamicin is surrogate for all the other aminoglycosides.
