Streptococcus pseudopneumoniae

Streptococcus pseudopneumoniae is a gram-positive coccus that may cause pneumonia in humans.^[1][2] It was first described in 2004.^[1] The organism is often mistaken for S. pneumoniae^[1] and its clinical importance is as yet uncertain. It seems likely that most cases of S. pseudopneumoniae pneumonia are misdiagnosed as S. pneumoniae.^[2]

Streptococcus pseudopneumoniae
Scientific classification
Domain:	Bacteria
Kingdom:	Bacillati
Phylum:	Bacillota
Class:	Bacilli
Order:	Lactobacillales
Family:	Streptococcaceae
Genus:	Streptococcus
Species:	S. pseudopneumoniae
Binomial name
Streptococcus pseudopneumoniae Arbique et al. 2004

The bacterium has a number of features that allows it to be distinguished from S. pneumoniae:^[2]

• There is no pneumococcal capsule (and is therefore not typable).^[2]
• It is not soluble in bile.^[2]
• It is sensitive to optochin when incubated in ambient air, but appears resistant or to have indeterminate susceptibility when incubated in 5% carbon dioxide.^[2]
• Commercial DNA probe hybridization tests (e.g., AccuProbe Streptococcus pneumoniae culture identification test; Gen-Probe, San Diego, CA) are falsely positive.^[2]

Penicillin is the treatment of choice.^[2] Most reported isolates are resistant to erythromycin and to tetracycline.