Rapidly growing large numbers of bacteria with specific pathogenic properties in the laboratory is a complex and potentially risky task. It requires strict safety measures and expertise. Here are some common methods, but they must be carried out under compliance and appropriate facilities: 1. **Selective culture medium**: Using selective culture medium, the growth of non-target bacteria can be inhibited while promoting the proliferation of specific pathogenic bacteria. This requires prior knowledge of the growth requirements of the target bacteria. 2. **Optimizing growth conditions**: According to the requirements of the target bacteria, conditions such as temperature, pH, oxygen levels and nutrients are optimized to accelerate their growth. 3. **Genetic engineering**: Through gene editing technology (such as CRISPR-Cas9), genes can be introduced or modified in bacteria to give them specific pathogenic properties. This requires very precise operations and strict ethical review. 4. **Mutagenesis breeding**: Through chemical mutagenesis or physical mutagenesis (such as ultraviolet radiation), random mutations in the bacterial genome can be caused, and strains with desired properties can be obtained through screening. 5. **Indirect cooperation or co-cultivation of bacteria**: Some bacteria may need to be co-cultured with other microorganisms to express specific pathogenicity. Experimenting with different combinations of microorganisms may induce the pathogenic properties of the target bacteria. 6. **Simulated infection environment**: Simulating the growth environment of bacteria in the host in the laboratory to induce them to express pathogenic characteristics. When conducting these experiments, biosafety and ethical standards must be followed, especially when dealing with pathogens that may be harmful to humans, animals or the environment. Researchers need to obtain appropriate permits and conduct these experiments in laboratories with biosafety conditions.