ばい菌

• Reading: ばいきん
• Romaji: baikin
• Kanji breakdown: 菌 (kin) — fungus, germ, bacteria
• Pronunciation: /bai.kiɴ/

Meaning

Germs; bacteria; a bug. Microorganisms that cause disease.

A colloquial noun for harmful microorganisms. More casual than 細菌 (saikin, bacteria) or 微生物 (biseibutsu, microorganism). Commonly used with children and in everyday hygiene contexts. The phrase ばい菌が入る (germs get in) is used when warning about wound infection. Also used as a cruel childhood insult (ばい菌扱い, treating someone like a germ/outcast), which has become a topic in bullying discussions.

Examples

1. 手を洗わないとばい菌がついたままだよ。 If you don't wash your hands, you'll still have germs on them.
2. 傷口からばい菌が入らないように消毒した。 I disinfected the wound to prevent germs from getting in.
3. 生肉にはばい菌がいるので十分に加熱してください。 Raw meat contains bacteria, so please cook it thoroughly.

Usage Guide

Context: hygiene, health, children, daily life

Tone: casual

Origin & History

From ばい (bai, from 黴 meaning mould/mildew) + 菌 (kin, fungus/germ). The first character is usually written in hiragana because the kanji 黴 is complex and uncommon.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal