Шұжық тәрізді бактерия: Streptococcus suis және адамға жұғу қаупі

Species of bacterium

Streptococcus suis is a peanut shaped, Gram positive bacterium, and an important pathogen of pigs. Endemic in nearly all countries with an extensive pig industry, S. suis is also a zoonotic disease, capable of transmission to humans from pigs. Humans can be infected with S. suis when they handle infected pig carcasses or meat, especially with exposed cuts and abrasions on their hands. Human infection can be severe, with meningitis, septicaemia, endocarditis, and deafness as possible outcomes of infection. Fatal cases of S. suis are uncommon, but not unknown.

The first sign in pigs is usually pyrexia and there may be sudden deaths in the herd. Respiratory disease, with pneumonia, nasal discharge and respiratory difficulties, may also be present. Neurological signs result from meningitis, and signs may be severe, ranging from tremors to seizures and death. Joints may become infected and pigs may be lame or have swollen limbs. Skin disease is another presentation, and reproductive disease can also occur. Meningitis is the most common presentation in humans. The bacterium can be isolated from various body fluids, and serological testing with an ELISA can also be performed. A smaller outbreak occurred at the same time in Hong Kong, affecting 11 people. A total of 204 human cases were documented during the Sichuan outbreak, with 38 fatalities. The human outbreak coincided with one in the local pig populations. There was no evidence of human to human transmission; all of the patients had been in direct contact with pigs. Many of the patients, and almost all of the fatal cases, had typical symptoms of Streptococcal toxic shock syndrome (STSS). To date, STSS has only been documented in patients infected with S. pyogenes, another member of the Streptococcus family but very different from S. suis. However, the bacteria isolates from the human and pig samples were clearly S. suis, and those isolates were able cause typical S. suis disease in piglets. The 2012 deaths of 64 of 66 children in Cambodia affected with a complex syndrome including meningitis and pneumonia has been linked to a multiple infection of the children with Dengue fever, Enterovirus 71 and S. suis The use of steroids in the treatment of the severe illness has also been associated with the deaths, and the WHO has advised against the use of steroids in the treatment of this syndrome.

Detection of the zoonotic bacterial pathogen Streptococcus suis was achieved using magnetic glycoparticles. The bacteria contain an adhesion protein for the carbohydrate sequence Gal 1,4Gal. After incubation with various amounts of the pathogen, magnetic concentration and ATP detection, bacterial levels down to 10^5 cfu could be detected.