Nigerian Microbiologist Bridget Ugochi Anyanwueze develops improved laboratory method to advance antimicrobial drug discovery and research

Her research introduces a time-dependent approach to measuring bacterial inhibition, offering additional information that could support the laboratory evaluation of potential antimicrobial compounds. As antimicrobial resistance continues to threaten global health, researchers are investigating new compounds capable of inhibiting bacterial growth and improving the laboratory methods used to evaluate their activity.

Among these efforts is the research of microbiologist Bridget Ugochi Anyanwueze, whose work examines how antibiotic inhibition zones develop over time and how these measurements could contribute to future antimicrobial investigations. Her sole-authored research paper, “An Improved in vitro Method for Quantifying the Kinetics of Bacterial Inhibition-Zone Development,” was published on June 27, 2026, in the IPS Journal of Applied Microbiology and Biotechnology, with link to article The study was conducted within her broader research interests in microbiology and antimicrobial activity, with her affiliation listed as the Department of Biology at Southeast Missouri State University, Cape Girardeau, United States.

The research addresses a limitation of the traditional Kirby-Bauer disc diffusion assay, a laboratory method used to assess bacterial susceptibility to antibiotics. Traditionally, the method measures the diameter of the clear zone surrounding an antibiotic disc after a specified incubation period. Although this measurement provides important information about bacterial susceptibility, it does not describe how the inhibition zone develops during the preceding hours.

Anyanwueze investigated whether repeated measurements could provide additional information about the progression of bacterial inhibition. Using Staphylococcus epidermidis as the test organism, she examined inhibition-zone development following exposure to ampicillin, erythromycin, and neomycin. Measurements were collected at 4, 8, 12, 16, 20, and 25 hours of incubation, allowing changes in inhibition-zone diameter and expansion rate to be examined over time.

The findings revealed that the antibiotics exhibited different patterns of inhibition-zone development. Ampicillin produced the greatest absolute increase in inhibition-zone diameter, expanding by 10.23 millimetres, while erythromycin demonstrated the highest percentage expansion at 137.9%. The study also found that inhibition zones generally expanded more rapidly during earlier observations before slowing at later incubation intervals.

These differences demonstrate that final inhibition-zone diameters do not capture every aspect of how inhibition zones develop. By incorporating repeated measurements, the improved approach provides additional quantitative information about the progression of measurable bacterial growth inhibition. The findings were supported by statistical analysis that identified significant effects of antibiotic type, incubation time, and their interaction, indicating that inhibition-zone development differed among the antibiotics investigated.

Beyond its methodological contribution, the research connects with Bridget’s broader scientific interest in discovering antimicrobial agents from medicinal plants. Her previous investigations involving Azadirachta indica (Neem), Moringa oleifera, and Jatropha tanjorensis, examined the antimicrobial properties of plant extracts against selected microorganisms.

These studies reflect her interest in identifying naturally occurring substances with potential applications in antimicrobial development. The inhibition-zone kinetics study offers a complementary direction by examining how laboratory measurements could provide more detailed information about antimicrobial activity. “With further validation, my method could be applied to investigate how inhibition zones develop following exposure to plant-derived antimicrobial compounds.

By comparing these patterns with those of established antibiotics, researchers may obtain additional information to support the characterization of potential antimicrobial candidates,” Bridget explained. This potential application is relevant to early-stage antimicrobial discovery, where researchers evaluate candidate compounds to determine whether they demonstrate sufficient activity to justify further investigation.

For example, researchers investigating medicinal plant extracts could use repeated inhibition-zone measurements to examine changes in zone diameter, relative expansion, and expansion rates during incubation. When combined with minimum inhibitory concentration testing and appropriate experimental controls, these measurements could complement established approaches for characterizing antimicrobial activity.

However, inhibition-zone development is influenced by several factors, including compound diffusion through agar, bacterial growth characteristics, concentration, and incubation conditions. Consequently, larger or faster-expanding inhibition zones do not necessarily indicate greater