Career
With Nina Springer and Wolfgang Ludwig he characterized the bacterium Parachlamydia acanthamoebae in 1997. As of 2011, he had an h-index of 78 and 19,173 citations to his 240 articles He was an Inter-Services Intelligence Highly Cited Researcher 2001 and 2014.
He is the Executive Editor of the journal Systematic and Applied Microbiology.