In Vitro Sensitivity of Mycoplasmas Isolated From Various Animals and Sewage to Antibiotics and Nitrofurans

Abstract

A total of 15 strains of Mycoplasmawere examined for in vitro sensitivity to 22 commonly used antibiotics and 9 nitrofurans. They were strains of Mycoplasma mycoides var. mycoides, M. mycoides var. capriy M. hyorhinis, M. suipneumoniae (hyopneumoniae), M. granularum, M. cams, M. pulmonis, M. arthritidiSy M. neurolyticum, M. gallisepticum, and M. laidlawii, all of which were isolated from various animals, except for one strain of M. laidlawii which was isolated from sewage. The sensitivity was determined by observing inhibition of growth in the agar and broth dilution systems. Amongall the mycoplasmasexamined, there were no markeddifferences in susceptibility to these drugs, with the exception of erythromycin and oleandomycin. Anti-tumor antibiotics, i. e., actinomycin D and mitomycin C, were the most active of all the agents. Tylosin, bottromycin, spiramycin and tetracycline followed them in activity. Kasugamycin, polymyxin B and colistin were noninhibitory. M.suipneumoniaeå , which is known as the etiological agent of swine enzootic pneumonia (SEP), and other species of respiratory mycoplasmas of swine were compared with regard to minimuminhibitory concentrations (MIC) upon these drugs. The sensitivity of M. suipneumoniae to the drugs used was similar to that of other mycoplasma. Amongthe new nitrofurans tested, drugs with high activity against the mycoplasma were discovered. Manystudies have been made previously on the sensitivity of various mycoplasmas to antimicrobial drugs. Because of the high host specificity of mycoplasmas, strains derived from the same individual host species were chiefly used in such studies.

In Vitro Susceptibility of Mycoplasma hyopneumoniae and Mycoplasma hyorhinis to Fifty-One Antimicrobial Agents

“…In addition, M. hyopneumoniae and M. hyorhinis strains were resistant to cephaloridine and cephalothin but susceptible to furazolidone; the M. hyopneumoniae strains were susceptible, and M. hyorhinis was resistant, to oleandomycin. Our strains of M. hyopneumoniae and M. hyorhinis were susceptible to erythromycin, but Ogata et al (8) found some strains to be resistant. Strains of M. hyopneumoniae, as tested, were resistant to ampicillin, methicillin sodium, and penicillin.…”

“…Strains of M. hyopneumoniae, as tested, were susceptible to kanamycin, but Ogata et al (8) found strains to show some resistance to the agent, with a MIC of 20 ,ug/ml. In addition, M. hyopneumoniae and M. hyorhinis strains were resistant to cephaloridine and cephalothin but susceptible to furazolidone; the M. hyopneumoniae strains were susceptible, and M. hyorhinis was resistant, to oleandomycin.…”

“…Although considerable information about the effect of antibiotics against avian, bovine, human, and saprophytic mycoplasmas has been accumulated (2,7,8,11), few reports are available on the effects of antimicrobial agents against porcine mycoplasmas, Mycoplasma hyopneumoniae and M. hyorhinis (3,8). This lack of information is due in part to the difficulty of growing porcine mycoplasmas, particularly M. hyopneumoniae, in cell-free medium and the lack of a convenient assay system for determining antimicrobial activities against porcine mycoplasmas.…”

“…Each mycoplasmal strain in log phase was diluted in MF medium to 101 to 106 colony-forming units (CFU)/ml. The diluted strains were aseptically dispensed in triplicate in 0.2-ml fractions in test tubes (13 by 100 mm) containing separate serially diluted antimicrobial agents (8). Inoculated tubes were then tightly screw capped, placed in a rack with appropriately labeled tubes of uninoculated medium controls, and incubated on a rocker platform (Beilco Glass Inc., Vineland, N.J.) at 370C in a walk-in Depending on the particular strain being tested, the strain showing susceptibility to a given antimicrobial agent was prevented from lowering the initial medium pH of 7.4 to a pH, of resistant strains to an agent, varying from 5.8 to 6.4 in 5 days of incubation at 37°C.…”

Crystal structure of 2-[3,5-bis(trifluoromethyl)benzylsulfanyl]-5-(5-bromothiophen-2-yl)-1,3,4-oxadiazole, C15H7BrF6N2OS2

“…The uorine atoms of the disorderd CF 3 -group were located on a di erence Fourier map and re ned freely. chemistry as pharmacophores or auxophores possessing diverse pharmacological activities, including antibacterial [1][2][3][4][5], anticancer [6][7][8][9][10], antiviral [11][12][13], antihypertensive [14,15], anti-in ammatory [16,17] and antioxidant [18] activities. In addition, some 1,3,4-oxadiazoles are currently used as safe herbicides for crop protection [19][20][21].…”