Optimized Media and Flow Cytometry Track Mycoplasma hyopneumoniae Growth in Real Time

Mycoplasma hyopneumoniae, the primary etiologic agent of swine enzootic pneumonia, is notoriously difficult to grow in the laboratory and in industrial settings. A study published in AMB Express on 2 October 2026 reports a practical attempt to ease that bottleneck, combining newly formulated culture media with a real-time growth monitoring platform for the CJ strain of the bacterium.

The researchers, led by Liangkun Zhang, Shuhong Gao, Kexin Xu and Li Chen, note that industrial production of the pathogen is severely constrained by its intrinsically slow growth, its fastidious nutrient demands, and the lack of robust real-time cell count quantification. Those constraints matter because vaccines remain the cornerstone of disease control, and vaccine manufacturing depends on reliable, scalable cultivation of the organism.

Conventional methods have added to the difficulty. The color change unit assay, a standard approach for quantifying mycoplasmas, requires 14 days of incubation, exhibits poor reproducibility, and precludes dynamic optimization of cultivation processes. In other words, producers have had little ability to adjust culture conditions while a batch is still running.

To address these problems, the team formulated two optimized Friis-based media, designated CL6 and GD-240.

The second major contribution is a dynamic monitoring platform that integrates a logistic growth model with flow cytometry. This combination was developed to enable real-time tracking of mycoplasma growth, replacing the need to wait days for a color change endpoint. From the platform, the researchers defined five key growth parameters that characterize how the organism behaves in each medium.

Kinetic profiling of the two formulations showed measurable differences. GD-240 increased maximum cell counts by 17.5 percent compared with the alternative, and it prolonged the rapid growth phase by 2.7 hours. Both figures come from the study’s model-based analysis of growth dynamics rather than from a single endpoint measurement, reflecting the continuous monitoring the platform makes possible.

Beyond cell counts, the study used quantitative PCR to clarify the temporal expression patterns of core metabolic and virulence genes during growth. As one example, the researchers found that deoB and ldh were upregulated at 30 hours and downregulated at 42 hours. This kind of time-resolved gene expression data offers a window into the physiology of the organism as it moves through different growth phases in a given medium.

The authors state that these practical methodological approaches were provided for the optimization of mycoplasma cultivation and dynamic physiological analysis. The work is presented as a methods-oriented contribution: it does not report vaccine efficacy or clinical outcomes, but rather tools and measurements intended to make cultivation of this slow-growing pathogen more controllable and better understood.

For researchers and manufacturers working with M. hyopneumoniae, the reported combination of optimized media, flow cytometry-based counting, and qPCR-based expression profiling offers a faster and more informative way to compare culture conditions than the traditional 14-day color change assay. The article, published as an open-access paper in AMB Express, is currently available as an accepted manuscript that is citable and carries a permanent DOI, with a final version of record to follow.

Subject of Research: Optimization of culture media and real-time growth monitoring for Mycoplasma hyopneumoniae

Article Title: Growth dynamic curve and gene expression analysis for optimized culture medium of Mycoplasma hyopneumoniae CJ strain

Article References: Zhang, L., Gao, S., Xu, K., & Chen, L. (2026). Growth dynamic curve and gene expression analysis for optimized culture medium of Mycoplasma hyopneumoniae CJ strain. AMB Express. https://doi.org/10.1186/s13568-026-02123-4

Image Credits: AI Generated

DOI: 10.1186/s13568-026-02123-4

Keywords: Mycoplasma hyopneumoniae, swine enzootic pneumonia, culture medium, flow cytometry, logistic growth model, qPCR, gene expression, Friis medium, vaccine production, microbiology, Growth, dynamic