Effect of antibiotics on the dynamics of color change in Ureaplasma urealyticum cultures

Abstract

Color change of pH indicators in broth medium is commonly used to quantify growth of ureaplasmas. These organisms differ from other members of the Mollicutes by their abiity to hydrolyze urea to C02 and NH3. This study describes a method which continuously monitors color change in ureaplasmal broth cultures. Using this technique we found: (i) there was a pH-dependent absorbance at 554 nm in ureaplasmal broth medium containing phenol red, (ii) a sigmoidalshaped color changing curve (absorbance at 554 nm versus time) was produced by metabolizing organisms whereas a linear curve was generated by antibioticinhibited ureaplasmas, and (iii) the minimum cell density which elicited a growthinhibited color change was 1.25 x 104 colony-forming units per ml. Others have shown that apparently dead ureaplasmas can cause a color change in broth media. This color change is probably due to the presence of an active urease. This study graphically and quantitatively assesses growth-inhibited color change.

Molecular characterization of thymidine kinase from Ureaplasma urealyticum: nucleoside analogues as potent inhibitors of mycoplasma growth

“…Ureaplasma growth was monitored by colour change of a pH indicator (phenol red) in the growth media, caused by urea hydrolysis (Robertson, 1978). The colour change was measured at 562 nm with a Titertek Multiscan spectrophotometer (Flow Laboratories) at different interval as described (Bloomster and Lynn, 1981). Mycoplasma pneumoniae growth was measured at various times, up to 7 days, by estimating the colour change in each well in comparison with the positive growth control of the same inoculum size (Nagata et al ., 1995).…”

Interaction of a monoclonal antibody with the urease ofUreaplasma urealyticum

“…Undiluted ureaplasma growth medium and an antimyosin antibody were included as controls (Table 1) to eliminate the possibility of a false positive reaction with serum components. The urease activities in the cytoplasmic fraction from 6 other serotypes (1,2,3,6,7,10) were blocked to the same extent as serotype 8, although by immunoblot somewhat different patterns were exhibited (Fig. 3).…”

“…U.u serotypes 1, 2, 3, 6, 7, 8 and 10 (kindly provided by Prof. E.A. Freundt, Aarhus, Denmark) were grown in a medium supplemented with horse serum and urea [7]. Mycoplasma genitalium and M. hominis were grown as described [8].…”

High-throughput tandem-microwell assay for ammonia repositions FDA-Approved drugs to Helicobacter pylori infection

“…To construct the HTS assay, we compared three reported protocols for determination of the activity of JBU by using salicylic acid-hypochlorite and Nessler detection reagent, as well as phenol red(20,26,27), which undergo the indophenol and Nessler’s reaction with NH 3 , respectively. Salicylic acid-hypochlorite and Nessler’s reagents could dose-dependently and time-dependently monitor the activity of JBU at various concentrations (Figures S1A and B); however, the phenol red failed to detect it (Figure S1C).…”