Spectra of Susceptibility of Neisseria meningitidis to Antimicrobial Agents In Vitro 1

Abstract

The minimal inhibitory concentrations of 49 antimicrobial agents for 37 to 40 meningococcal strains freshly isolated from the nasopharynx of healthy carriers were determined. Coumermycin A1 and rifampin were the most effective agents tested. The geometric mean values of the minimal inhibitory concentrations for coumermycin A1 and rifampin were 0.0001 and 0.02,qg/ml, respectively. Sulfadiazine was effective during World War II both as a chemotherapeutic agent in meningococcal disease and as a chemoprophylactic agent in the elimination of meningococci from the nasopharynx of healthy carriers (2, 7, 13). Vollum and Griffiths (16) reported the successful prevention of meningitis in Nigeria by the administration of four 1-g doses of sulfonamide snuff over a period of 2 days. Although penicillin has replaced sulfadiazine in the treatment of meningococcal disease (14), sulfadiazine remains the most widely used antimicrobial agent against nasopharyngeal carriers of meningococci. Since Millar et al. (12) reported, in 1963, the prevalence of sulfadiazine-resistant meningococci among Naval personnel at the San Diego Naval Training Center, there has been no known effective antibacterial agent for controlling the spread of sulfadiazine-resistant meningococci. The prevalence of carriers of sulfadiazine-resistant meningococci among Naval personnel was discussed by Devine et al. (3) in 1969. Eickhoff and Finland (5), in 1965, reported on the spectrum of susceptibility in vitro of meningococci to sulfadiazine and several other commonly used antibiotics available at that time. Dowd et al. (4) reported the failure of oxytetracycline, erythromycin, penicillin G, and ampicillin to eliminate the meningococcal carrier state. Erythromycin estolate, doxycycline, and sulfadiazine plus pyrimethamine failed to eliminate sulfadiazine-resistant meningococci from the nasopharynx of carriers (3). The incidence of meningococcal disease among military recruits is much higher than among similar age groups of civilians (14). A prophylactic drug for control of epidemics is needed. Conse-' This investigation made in connection with Research Project M4305.

Pharmacodynamics of Antimicrobials against Mycoplasma mycoides mycoides Small Colony, the Causative Agent of Contagious Bovine Pleuropneumonia

“…In marked contrast to danofloxacin and OTC, the MIC of tulathromycin was approximately 330-fold lower in serum. Such a low MIC (0.06 µg/L) is not unprecedented; Devine and Hagerman [37] reported an MIC of 0.1 µg/L for coumermycin A 1 against Neisseria meningitidis . The potency of the weak base tulathromycin in acidic conditions is expected to be lower due to ionisation and the consequent inability to penetrate cell membranes.…”

Susceptibility of Neisseria meningitidis Strains from the Civilian Population to Sulfadiazine, Penicillin, and Rifampin

“…The zone sizes ranged from 32 to 50 mm for MIC values of 0.01 to 0.2 Ag/ml. DISCUSSION Several workers (5,7,15) dissolved rifampin in ethanol or methanol for their sensitivity studies. The lot of rifampin used in this study was only partially soluble in ethanol; however, this lot was completely soluble in DMSO and in N,N dimethyl formamide which were used as solvents by other workers (6,12,14).…”

“…These workers have used rifampin to treat carriers in military and civilian groups. Devine and Hagerman (7) have established the in vitro sensitivities to rifampin of meningococci strains from healthy military carriers. It is important that a base line of sensitivity to rifampin be established for meningococcal strains isolated from the civilian population and that these findings be related to the sensitivity of these same strains to sulfadiazine and penicillin.…”