Overview
Selective broth medium is a microbiological growth medium designed to favor the growth of target microorganisms while suppressing competing flora. It typically consists of a nutrient base (e.g., tryptone, peptones) combined with selective agents such as antibiotics, dyes, or salts. These media are crucial for isolating pathogens from complex samples like clinical specimens, food, or environmental swabs. Unlike general-purpose media, selective broths incorporate chemical inhibitors that exploit biochemical differences between microbial species. For example, MacConkey broth contains bile salts to select for Gram-negative bacteria, while Selenite F broth inhibits Gram-positive organisms. Their liquid form allows for enrichment of low-concentration targets through incubation before plating on solid media.
Physical and Chemical Properties
Selective broths are aqueous solutions with adjusted pH (usually 7.2-7.4) and may contain pH indicators like phenol red for visual monitoring. Their osmotic pressure is isotonic to prevent cell lysis. The selective components vary widely: antibiotics (e.g., vancomycin), heavy metals (e.g., tellurite), or surfactants (e.g., sodium lauryl sulfate) are common. Most commercial formulations are pre-sterilized by filtration or autoclaving and remain stable for 6-12 months when refrigerated. Color changes (e.g., from tetrazolium reduction) often signal microbial growth. Some broths include resuscitation agents to repair stressed cells, enhancing detection of injured pathogens in processed foods or treated wastewater.
Main Applications
In clinical labs, selective broths like GN Hajna or Tetrathionate broth are used to isolate Salmonella and Shigella from stool samples. Food testing employs Listeria Enrichment Broth (LEB) or Buffered Peptone Water with selective supplements to detect pathogens per ISO and FDA standards. The pharmaceutical industry uses Thioglycollate Medium for sterility testing, while environmental monitoring relies on Azide Dextrose Broth for water coliform counts. Recent advances include chromogenic broths that combine selection with color-based identification, reducing the need for subculturing. Dual-purpose broths also exist, such as Rappaport-Vassiliadis broth that simultaneously enriches and selects for Salmonella at elevated temperatures.
Safety and Storage
Selective agents like sodium azide or antimicrobials pose health risks; always consult SDS sheets. Use gloves and eye protection when handling, especially with powdered formulations. Avoid mouth pipetting due to potential pathogen exposure after inoculation. Store unopened bottles at 2-8°C, avoiding freezing. Once opened, use within 2 weeks to prevent contamination or component degradation. Discard any medium showing precipitation, color change, or turbidity. Autoclave used broths before disposal to inactivate pathogens. For heat-sensitive components (e.g., antibiotics), aseptic addition post-autoclaving is required—follow manufacturer's reconstitution guidelines precisely.
B2B Procurement Guide
When sourcing selective broths, specify the target organism and required selectivity (e.g., 'suppresses E. coli but not S. aureus'). Verify compliance with relevant standards (e.g., USP, EP for pharmaceuticals; ISO 11133 for food). Bulk purchases (10+ liters) typically offer 15-30% cost savings but require validated shelf-life extension protocols. Prefabricated media in sterile, ready-to-use bottles reduce lab preparation time but cost 20-50% more than powder formulations. For global shipments, ensure cold chain logistics with temperature monitoring. Key suppliers include Merck, Thermo Fisher, and HiMedia—request certificates of analysis for each batch, particularly for antibiotic-containing media where potency variations affect performance.
Related Manufacturers
- 主营：马铃薯、增菌液、噬菌体、培养基、营养盐、串珠菌、琼脂粉、西红柿、活性炭、营养液、酵母氮、基础盐、血琼脂、酵母膏、磁螺菌、缓冲液、抑菌剂、氯化钠、玉米粉、三糖铁、洗脱液、中和剂、结冷胶、沉降菌、橄榄油
- 主营：培养皿、菌检测、菌落计数器、培养基、ms培养基、支原体培养基、路桥培养基、马铃薯葡萄糖琼脂培养基、三药培养基、海博培养基、水质检测、微生物检测仪器设备、接种环、微生物检验、微生物检测、程控定量封口机、菌种鉴定
- 主营：科研试剂、高效试剂
- 主营：琼脂培养基
- 主营：折射仪、钼酸铵、弹簧钢、分装瓶、指示剂、水分仪、方钢坯、合金钢、容器板、离子计、测定仪、容器钢、六角钢、测试片、样品瓶、浊度计、穿线管、齿轮钢、测试笔、切定尺、样品杯、清洗液、比色皿、排型钢、移液管
- 主营：架桥剂、YW100 锂萃取剂、端羧基液体丁腈橡胶、肉汤、10-羟基癸酸、苯乙烯磷酸、肉豆蔻酸镁、硬脂酸钴、全氟三丁胺、乙烯基磷酸二乙酯、磷酸锰铁锂、β-磷酸三钙、十一烯酸、钨酸铝、1-乙炔基环已醇、间二异丙苯、锂硅合金、溴甲酚绿、生物活性玻璃、溴代海因树脂颗粒、红铝、龙涎酮、原丁酸三甲酯
- 主营：实验细胞、微生物菌种、微生物质控品、标准物质
- 主营：培养基默克培养基、标准品、DRE
- 主营：冻存管、淋洗液发生罐、阴离子抑制器、样品瓶、试剂槽、色谱柱、离子色谱柱、细胞过滤器
- 主营：无菌培养基现货、分析纯试剂
- 主营：2ml冻存管、5ml样品瓶、淋洗液发生罐、八联管、巴氏吸管、试剂槽、细胞过滤器、冷冻管、无粉乳胶手套、移液器、离心管、丁腈手套、棕色冻存管、细胞培养锥形瓶、移液管、冻存盒、2mL样品瓶、冻存管
- 主营：无水乙醇、乙酸乙酯、磷酸、营养肉汤、甲醇、乙二醇、二氯甲烷、异丙醇、二甲苯、各种化学试剂、化工原料
- 主营：离心瓶、冻存管、冻存盒、巴氏吸管、细胞过滤器、乳胶手套、丁腈手套、淋洗液发生罐、样品瓶、导电吸头、移液管、采样锥、截取锥、离子色谱柱、离子抑制器、萃取池、氘灯、石墨管、萃取小柱
- 主营：化工中间体、有机中间体、香精香料、大豆肉汤、添加剂、表面活性剂、天然/合成树脂、分析试剂、日化原料、催化剂、高分子材料
- 主营：透析袋、移液器、SIGMA、肉汤培养基、赛默飞、爱思进、康宁、离心管、巴氏吸管、保存管、封板膜、细胞爬片、滤器、ELISA试剂盒
- 主营：7h9肉汤、肉汤管、琼脂培养基、大肠杆菌、磷酸盐缓冲液、胰蛋白胨胆盐
- 主营：透析袋、移液器、SIGMA、肉汤培养基、赛默飞、爱思进、吸头/枪头、离心管、巴氏吸管、保存管、封板膜、细胞爬片、滤器、ELISA试剂盒
- 主营：上海佑科、实验设备、检测仪器、分光光度计、水分测定仪、气相色谱仪、华港通科技、舜宇科技、鼎泰高科、洁盟超声、超声波清洗机、世纪方舟仪器、普析仪器、安捷伦、气象色谱柱、日本岛津、三信仪器、大龙仪器、标准物质、北京奥博星、生物试剂、化学试剂