Table 1.

β-Lactamase-mediated ampicillin resistance among respiratory tract isolates of H. influenzae and M. catarrhalis from U.S. and Canadian medical centers

CountrySiteH. influenzaeM. catarrhalis
No. of isolates% β-Lactamase positiveNo. of isolates% β-Lactamase positive
United StatesVeterans Administration Medical Center, Boston, Mass.3520.01888.9
Columbia Presbyterian Medical Center, New York, N.Y.3729.71593.3
Long Island Jewish Medical Center, New Hyde Park, N.Y.3125.87100.0
Strong Memorial Hospital, Rochester, N.Y.3943.61989.5
The Medical Center of Delaware, Wilmington3243.81984.2
University of Virginia Health Sciences Center, Charlottesville1637.55100.0
Carolinas Medical Center, Charlotte, N.C.4037.51989.5
University Medical Center, Jacksonville, Fla.3727.02085.0
University of Mississippi Medical Center, Jackson2138.19100.0
University of Louisville Hospital, Louisville, Ky.3330.32095.0
Summa Health Systems, Akron, Ohio3732.4666.7
Henry Ford Hospital, Detroit, Mich.3847.41593.3
Methodist Hospital of Indiana, Indianapolis3923.11687.5
Northwestern Memorial Hospital, Chicago, Ill.1533.34100.0
University of Illinois Hospital, Chicago2250.01090.0
Froedtert Memorial Lutheran Hospital, Milwaukee, Wis.4037.51070.0
Barnes-Jewish Hospital, St. Louis, Mo.2123.81080.0
University of Iowa Hospitals and Clinics, Iowa City3548.620100.0
Creighton University Medical Center, Omaha, Nebr.3729.71888.9
Parkland Health & Hospital System, Dallas, Tex.911.1785.7
University of Texas Medical Branch at Galveston, Galveston2433.321100.0
Denver General Hospital, Denver, Colo.2934.5466.7
University of New Mexico Hospital, Albuquerque3938.510100.0
St. Jude Medical Center, Fullerton, Calif.3630.611100.0
Kaiser Regional Laboratory, Berkeley, Calif.3135.517100.0
Sacred Heart Medical Center, Spokane, Wash.3318.22195.2
University of Washington, Seattle2548.010100.0
Subtotal (United States)83734.237492.0
CanadaQueen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia3948.72185.7
Royal Victoria Hospital, Montreal, Quebec3423.51675.0
Ottawa General Hospital, Ottawa, Ontario3821.120100.0
Mount Sinai Hospital, Toronto, Ontario1926.320100.0
The Hospital for Sick Children, Toronto, Ontario3737.817100.0
Health Sciences Centre, Winnipeg, Manitoba3528.62395.7
University of Alberta Hospital Site, Edmonton3828.91291.7
Subtotal (Canada)24031.312993.0
Grand total1,07733.550392.2