The most comprehensive handbook of microorganisms, Bergey's Manual of Systematic Bacteriology, lists about 4,000 types of bacteria.

最全面的微生物手册《伯吉氏系统化细菌学手册》列出了大约4000种细菌。

They found that this single small sample contained between 4,000 and 5,000 separate bacterial species, more than in the whole of Bergey's Manual.

他们发现，这个小小的样品里就有4000-5000种不同的细菌，比《伯吉氏手册》里收录的全部数量还要多。