Publication:Dialister pneumosintes Associated with Human Brain Abscesses

Rousée, J. M. et al. “Dialister pneumosintes Associated with Human Brain Abscesses.” Journal of Clinical Microbiology 40, no. 10(2013): 3871–3873. Accessed April 11th,1023.

It is amazing when scientist discover that the smallest bacterium present in the earth is responsible for deadly diseases in the human population. The Dialister Pneumosintes is the smallest bacteria known to mind kind. The size of the bacteria is approximately 0.5×0.5×1.6 µm. The bacterium is a nonfermentative, anaerobic, gram-negative rod which grows with small, circular, transparent, shiny, smooth colonies on blood agar. The bacteria cannot be identified by morphological and traditional methods and therefore is identified by sequencing of the 16S rRNA gene. A few years ago the bacteria was isolated from two patients by way of a blood culture and from a brain abscess in the brain.

The first patient from which the bacterium was isolated had various flu-like symptoms. Along with a high fever, a left temporal head ache and paralysis to an arm, there was also swelling of lymph nodes. Doctors passed this off as symptoms of a normal fever and treated it with antibiotics. However, as time went by the condition of the patient became worst. This lead to a CT scan which revealed an empyma compressing the frontal lobe .The empyma was evacuated and the frontal sinus drained and examined. Colonies of Streptococcus angrinosus were isolated. These are recognized as normal flora which if present in excess can lead to brain abscess. However the Streptoccus angrinosus were present in small amounts. Further examination of the empyma isolated Dialister pneumosintes. All other blood cultures tested negative for the presence of other bacteria.

The second patient displayed a variety of symptoms. He was admitted to the hospital for right-side tonic-clonic seizures. When examined the patient did not have a fever but was postictal and had a right side hemiparesis . A craniotomy was performed on the patient and green pus was drained from the frontal brain tissue. Examination of the sample revealed numerous Streptoccocus cells, gram positive rods and rare cultures of Diaslister pneumonsintes.

Before these two cases the bacteria was suspected to be involved in the formation of brain infections. This was never confirmed because of poor results of phenotypic characterization from the sequencing of the 16s rRNA. Doctors firmly believe that the two cases afore mentioned link Dialister pneumosintes with brain infections. In the first patient this was proved by the identification of the bacteria by the gram staining results and microscopic examination. The bacterium was believed to be the source of the infection in the frontal lobe. In the second patient the culture from the brain proved the involvement of the bacteria with the abscess. The scientists believe that the gram-positive stain was only achieved because of inadequate decolorization of the gram stain. From previous phenotypic characterization from gene sequencing the bacteria was expected to be present in oral cavities,nasopharyngeal and vaginal flora. It is believed that the bacterium is also responsible for gingivitis. From this it has been concluded that Diaslister pneumosintes in mixed flora can act as a deadly pathogen.

The findings of the research are very fascinating. However I find that two patients are not enough to confirm the involvement of the bacterium with brain infections. It is my belief that the doctors should continue to look for new ways to identify the organism. The fact may be that the infections were caused by other bacteria which were not identified by the cultures or even the Streptococcus bacteria which were identified. To be absolute positive that the Dialister pneumosintes caused the infection, a lot more research needs to be done.