The activities of 16 antimicrobial agents against 103 clinical isolates of Campylobacterjejuni were tested. All the strains were susceptible to kanamycin and gentamicin. Chloramphenicol, nalidixic acid, and clindamycin were active against most of the strains. More than one-third of the strains were resistant to the tetracyclines and 12.5% were resistant to erythromycin.During the past few years, several reports have dealt with the susceptibility of Campylobacterjejuni to antimicrobial agents (1-7). Studies have shown geographical differences in the frequency of resistance of this organism to some drugs, especially erythromycin and tetracycline (1,3,6 (Oxford) and Escherichia coli ATCC 25922. The plates were incubated at 37°C under microaerophilic conditions as described above, and the results were read after 48 h. The minimal inhibitory concentration (MIC) was defined as the lowest concentration of antimicrobial agent that prevented macroscopic growth.For the two control strains, the MIC of each drug always fell into the expected range of concentrations. The susceptibilities of the isolates to the antimicrobial agents studied are summarized in Table 1. All the strains were susceptible to kanamycin and particularly to gentamicin, which was active at low concentrations (50% MIC, 0.125 ,ug/ml; 90% MIC, 0.25 ,ug/ml). All but one strain were susceptible to chloramphenicol and nalidixic acid. Clindamycin was active against almost all the isolates, and its activity was better than that of erythromycin, to which 12.6% of the strains were resistant. A higher percentage of isolates were also resistant to the two tested tetracyclines (37.9% to tetracycline and 38.8% to doxycycline). More than 50%o of the strains were susceptible to ampicillin (50% MIC, 4.0 ,ug/ml). Penicillin G, polymyxin B, colistin, sulfamethoxazole, and co-trimoxazole showed little activity against the strains. Cefazolin and trimethoprim were completely inactive.Our results are in general agreement with previous reports on the susceptibilities of C. jejuni isolates to antimicrobial agents (1-7). However, our isolates showed an unusual resistance to erythromycin and the tetracyclines.

A total of 229 clinical isolates of Streptococcus pneumoniae recovered from 225 patients were serotyped and tested for susceptibility to penicillin G, ampicillin, mezlocillin, cefazolin, erythromycin, clindamycin, chloramphenicol, and sulfamethoxazole-trimethoprim. Of all the isolates, 48 Penicillin resistance in pneumococci has been reported in many parts of the world during the last few years, and the problem has been recently reviewed (13). The degree of penicillin resistance reported for pneumococci is variable, but even with strains having intermediate resistance to penicillin (PIR strains), unsuccessful treatment, especially of meningitis, has been reported (1,3,4,7,11). Information about serotypes of penicillin-resistant (PR) pneumococcal strains is needed in order to design an epidemiological policy for control measures (13) and because the effectiveness of the 14-valent pneumococcal vaccine to prevent the development of systemic pneumococcal disease and reduce the transmission of PR strains (8) depends on the inclusion of appropriate serotypes. In addition, studies on the susceptibility of PR strains to other antimicrobial agents are important to detect multiply resistant organisms and to assess alternative therapeutic approaches (13).The purpose of this work was twofold: (i) to investigate the susceptibility of clinically significant isolates of Streptococcus pneumoniae to penicillin G and to other antimicrobial agents used in the treatment pf pneumococcal infections, and (ii) to establish the serotype distribution of the PR strains. plied for each isolate included the age, sex, and ethnic origin of the patient, source of isolation, and mortality. Typing was performed with sera supplied by the Statens Seruminstitut, Copenhagen, Denmark. The bacteria were lyophilized and stored at 4°C until tested. Confirmation and final typing were performed at the Statens Seruminstitut by Henrichsen. Three different serotypes in one patient and two different serotypes in each of two additional patients were isolated from ear pus sampled on different dates. Susceptibility testing. Since one strain was isolated from both blood and cerebrospinal fluid cultures of the same patient, 229 isolates were tested for susceptibility to penicillin G, ampicilLin, cefazolin, mezlocillin, erythromycin, clindamycin, chloramphenicol, and sulfamethoxazole-trimethoprim by the agar dilution method (16) with Iso-Sensitest agar (Oxoid Ltd., London) supplemented with 5% defibrinated human blood. All the antibacterial media were freshly prepared and used within 48 h of preparation. The test organisms were grown overnight in Todd-Hewitt broth (Difco Laboratories, Detroit, Mich.) at 37°C. The cultures were adequately diluted to give a final inoculum of about 105 CFU in each spot with a multipoint inoculator (400 U; Mast). Controls were prepared with Staph-