The detection of penicillin-resistant pneumococci. The compliance of hospital laboratories with recommended methods.

Isolations of pneumococci with diminished susceptibility to penicillin have been reported with increasing frequency in recent years. The first reported isolations of such organisms in Tennessee occurred in December 1982, and prompted a survey of acute-care hospitals to determine the methods being used to test pneumococcal isolates for penicillin susceptibility. All 77 acute-care hospitals in Tennessee with 100 or more beds were surveyed. Eighteen (23%) did not test the penicillin susceptibility of any pneumococcal isolates obtained from blood or cerebrospinal fluid. Thirty-eight hospitals (49%) tested some or all such isolates, but did not perform the tests in accord with established standards; 21 (27%) properly tested all such isolates. There was no correlation between the proper testing of pneumococcal isolates for penicillin susceptibility and the mode of governance, numbers of beds, or medical school affiliations of the respondent hospitals. It is recommended that appropriate pneumococcal isolates be tested for penicillin susceptibility. Such testing is most reliably performed by the disk diffusion method, using a 1-microgram oxacillin disk.