Hydrogen Sulfide levels are often used to diagnosis SIBO. (Hydrogen sulphide in exhaled breath: a potential biomarker for small intestinal bacterial overgrowth in IBS. 2016) Today I saw a naive comment and would like to educate SIBO folks on what is known from actual studies.
“Hydrogen sulfide producing bacteria are gram negative proteobacteria.A post on Facebook
Who produces hydrogen sulfide?
- Fusobacterium from cysteine 
- Fusobacterium nucleatum 
- Desulfosporosinus orientis (gram POSITIVE) and Desulfovibrio desulfuricans 
- Low pH 
- Saccharomyces cerevisiae  aka saccharomyces boulardii
- Bilophila wadsworthia from taurine 
- Mycoplasma pneumoniae 
- Veillonella from cysteine, Veillonella dispar, Veillonella parvula 
- Tissierella from peptone, Desulfosporosinus 
- Desulfovibrio piger, Lactate has the potential to promote hydrogen sulphide formation in the human colon.
- Veillonella, Actinomyces , Prevotella 
- Enterococcus faecium strain L86 reduced it