Anin vitrocomparison of the effect of some antibacterial, antifungal and antiprotozoal agents on various strains ofMycoplasma(pleuropneumonia–like organisms: P.P.L.O.)

Abstract

A study was made in liquid medium over 7 days at 37° C. of the inhibitory action of nineteen antibacterial, antifungal and antiprotozoal drugs on twenty strains ofM. gallisepticum, eight other avian mycoplasmata, six mammalian mycoplasmata, two saprophytic mycoplasmata and the L-form ofStreptobacillus moniliformis(L–1).The twenty strains ofM. gallisepticumfrom Britain and other countries showed a similar range of drug sensitivity except where resistant strains were included. Tylosin and demethylchlortetracycline appeared to have the highest inhibitory action, followed by erythromycin, spiramycin, tetracycline, chlortetracycline, oxytetracycline and ethidium bromide. A ‘Zone Phenomenon’ frequently occurred with sodium aurothiomalate, inhibition often being observed between 0·1 and 2·0 μg./ml. Polymixin and nystatin had no inhibitory effect on the growth of any mycoplasmata tested. With the exception of erythromycin and streptomycin in some cases, the pattern of sensitivity observed with the mycoplasmata of diverse origin was similar to that ofM. gallisepticum, most strains, however, being somewhat more resistant thanM. gallisepticumto many of the drugs.

Sodium Aurothiomalate, Gold Keratinate, and Various Tetracyclines in Mycoplasma-Induced Arthritis of Rodents

“…Some difficulty was experienced, however, in obtaining consistent end-points in MIC titrations with the gold-containing drugs. Similar difficulties in assessing the in-vitro activity of ATM against human urogenital-tract mycoplasmas and against numerous strains of M. gallisepticum have been reported previously (Robinson, Wichelhausen and Brown, 1952;Newnham and Chu, 1965 carry-over contrast to the gold-containing compounds, the tetracyclines displayed activity at very low levels against M. arthritidis and M. pulmonis even after 7 days' incubation. It can be seen from table I1 that all the drugs examined were predominantly mycoplasmastatic in action.…”

“…Gold keratinate was virtually inactive against M. pulmonis. The " zoning " phenomenon, which occurs in tests for antimycoplasmal activity of gold-containing compounds against certain mycoplasma species (Newnham and Chu, 1965 ;Davidson and Thomas, 1966), was not observed with M. arthritidis or M . pulmonis.…”

Development of antibiotic resistance inMycoplasma gallisepticum in vitro

“…The phenomenon was attributed to the acquisition of antibiotic resistance and this was confirmed in the report of Fahey in 1957. Mataney (1957, Osborn & Pomeroy (1958), Osborn et al (1960) and Newnham and Chu (1965) observed that different strains of mycoplasmas showed considerable variations in sensitivity to a given antibiotic, probably due to extended or improperly administered therapy. Domermuth (1958Domermuth ( , 1960, Osborn et al (1960), Kiser et al (1961) and Zanella (1966) used a number of antibiotics to study, both in vivo and in vitro, how antibiotic resistance was induced in Mycoplasma gallisepticum (Mg).…”

In vitro evaluation of various antimicrobials against Mycoplasma gallisepticum and Mycoplasma synoviae by the micro‐broth method, and comparison with a commercially‐prepared test system

“…In vitro sensitivity of M. gallisepticum (Mg) and M. synoviae (Ms) to antimicrobials has been the subject of a number of studies (for example : Newnham & Chu, 1965;Kleven & Anderson, 1971;Levisohn, 1981;Whithear et al, 1983;Jordan & Knight, 1984;Lin, 1987;Jordan et al, 1989;Kempf et al, 1989, Tanner & Wu, 1992. Recently, a number of quinolone antibacterial agents have been synthesized which show improved anti-mycoplasma activity over the quinolone compounds that were available hitherto (Hannan et al, 1989).…”