Department of Pharmacy

Introduction

This document is designed to assist the clinician in the selection of empiric antimicrobial therapy for initial infections. Whenever possible, only the first isolate of a given species from an individual patient has been included for analysis. Historical information on changing patterns of Staphylococcus aureus and Escherichia coli can be found on this webpage.

The Clinical Microbiology Laboratory utilizes microdilution MIC testing as the primary method of susceptibility testing, and supplements this testing as needed by the addition of other methods such as disk diffusion and the Etest.

Interpretation of testing results (S, I, or R) is based on guidelines developed by the Clinical Laboratory Standards Institute (CLSI). Selection of antimicrobials to be tested is made in collaboration with the pediatric and adult Infectious Diseases faculties, the hospital Pharmacy Department, and the Antibiotic Review Committee.

The Clinical Microbiology Department can develop antibiograms for specific areas of the medical center (specific floors or special care units, or individual clinics). Discuss your requests with the Director of Clinical Microbiology or with the Manager, Frances Williams (ext. 57846).

Haemophilus Influenzae (101 Isolates) (PDF Version)

PERCENT SUSCEPTIBLE TO ANTIBIOTIC TESTED

	Penicillin/Ampicillin
% Susceptible	86

Gram Positive Cocci (PDF Version)

PERCENT ORGANISMS SUSCEPTIBLE TO ANTIBIOTIC TESTED

	Number of Isolates Tested	Ampicillin	Penicillin	Oxacillin	Erythromycin	Clindamycin	Ciprofloxacin	Gentamicin	Vancomycin	Trimethoprim/Sulfamethoxazole	Tetracycline	Rifampin	Nitrofurantoin Only Urines Tested	Percent of isolates from urine
In-Patients, Staph. aureus,methicillin susceptible (42%)	376		22	100	68	82	91	98	100	99	94	99	100	10
In-Patients, Staph. aureus,methicillin resistant (58%)	511		0	0	10	73	50	97	100	98	89	91	97	8
Out-Patients, Staph. aureus,methicillin susceptible (40%)	396		20	100	59	83	89	99	100	100	93	99	99	26
Out-Patients, Staph. aureus,methicillin resistant (60%)	588		0	0	9	85	56	96	100	97	94	99	100	11
Staph epidermidis	583		5	18	17	44	47	55	100	53	88	92
Staph. coag. neg.* IP+OP	703		14	36	29	64	51	77	100	59	84	96	98	39
Enterococcus species**	620	99					74		100				99	77
Enterococcus faecalis	132	96					62		95
Enterococcus faecium	106	1					0		16

*Not identified to species level unless isolated from a normally sterile site.
**Not identified to species level unless isolated from a normally sterile site or resistance is seen to ampicillin and/or vancomycin.

Streptococcus Pneumoniae (91 Isolates) (PDF Version)

PERCENT SUSCEPTIBLE TO ANTIBIOTIC TESTED

	Penicillin	Cefotaxime: non-CSF*	Cefotaxime: CSF*	Ceftriaxone: non-CSF*	Ceftriaxone: CSF*	Chloramphenicol	Vancomycin	Erythromycin	Trimethoprim/Sulfamethoxazole	Tetracycline	Clindamycin	Moxifloxacin
% Susceptible	54	92	83	98	86	98	100	52	70	70	73	100
% Intermediate	36	8	9	2	12
% Resistant	10	0	8	0	2

*Interpreted using CLSI standards.

Fermentative Gram Negative Rods (PDF Version)

PERCENT ORGANISMS SUSCEPTIBLE TO ANTIBIOTIC TESTED

	Number of Isolates Tested	Ampicillin	Amoxicillin/Clavulanate	Ampicillin/Sulbactam	Timentin	Piperacillin/Tazobactam	Cefazolin	Ceftazidine	Ceftriaxone	Cefuroxime	Amikacin	Gentamicin	Tobramycin	Ciprofloxacin	Aztreonam	Imipenem	Trimethoprim/Sulfamethoxazole	Tetracycline	Nitrofurantoin Only Urines Tested	Percent of isolates from urine
Escherichia coli: Inpatient	577	43	88	48	86	94	84	97	97	97	99	85	86	69	97	>99	70	71	99	59
Escherichia coli: Outpatient	1267	51	93	57	90	98	91	98	98	95	100	89	89	75	97	100	71	75	98	92
Klebsiella pneumoniae	591	0	94	82	93	94	91	95	94	83	99	94	95	91	94	>99	91	71	54	61
Enterobacter cloacae	198	0	2	7	68	84	0	82	78	32	99	96	97	95	85	100	91	89	25	30
Enterobacter aerogenes	101	0	4	55	77	94	0	80	85	66	98	98	99	96	93	99	89	86	28	40
Serratia marcescens	122	0	0	8	92	87	0	87	95	0	99	98	86	90	85	100	97	9	0	27
Citrobacter koseri	103	0	98	97	100	96	98	100	99	89	99	100	100	99	95	100	100	91	93	58
Citrobacter freundii	66	0	24	50	70	91	0	76	76	61	100	91	92	85	76	100	80	92	89	71
Proteus mirabilis	378	90	98	92	98	100	92	98	99	97	98	90	91	89	93	100	91	4	0	57
Morganella morganii	63	0	5	8	89	97	0	81	97	6	100	79	87	76	92	100	71	42	0	60
Providencia stuartii	27	0	0	0	85	89	0	78	89	56	89	74	67	44	85	96	56	5	0	30
Shigella sp. (2001-2008)	41	17												100			90
Salmonella sp. (2001-2008)	41	88							100					100			100

Nonfermentative Gram Negative Rods (PDF Version)

PERCENT ORGANISMS SUSCEPTIBLE TO ANTIBIOTIC TESTED

	Number of IsolatesTested	Piperacillin	Timentin	Piperacillin/Tazobactam	Ceftazidine	Ceftriaxone	Cefotaxime	Amikacin	Gentamicin	Tobramycin	Ciprofloxacin	Aztreonam	Imipenem	Trimethoprim/Sulfamethoxazole
Acinetobacter baumannii	136	67	74	NT	84	56	53	97	71	76	71	NT	95	74
Stenotrophomonas maltophilia	61	NT	61	NT	66	NT	NT	NT	NT	NT	NT	NT	NT	100
Pseudomonas aeruginosa: Inpatients	217	73	NT	76	74	15	8	89	72	87	70	64	71	NT
Pseudomonas aeruginosa: Outpatients	77	94	NT	95	91	29	17	92	77	86	66	76	91	NT

• NT = Not Tested