bacteria意思是細菌，有致病的也有不致病的。

germs通常指的是有害菌，病菌。

例句如下所示：

bacteria

1、Chlorine is added to kill bacteria.

加氯是為了殺死細菌。

2、To confirm the diagnosis, the hospital laboratory must culture a colony of bacteria.

為進一步確診，醫院實驗室必須培養一個細菌菌落。

3、If your urine specimen shows the presence of bacteria, you"ll be prescribed antibiotics.

如果你的尿樣顯示有細菌存在，醫生會給你開抗生素。

germs

1、The wound was infected with germs.

傷口沾染了細菌。

2、Germs invade the organism.

病菌會侵入機體。

3、Chlorine is widely used to kill germs.

氯氣被廣泛用於殺菌。