pneumococcal meningitis

WordNet

1. infectious disease characterized by inflammation of the meninges (the tissues that surround the brain or spinal cord) usually caused by a bacterial infection; symptoms include headache and stiff neck and fever and nausea
2. of or derived from or caused by bacteria of the genus pneumococcus

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1. 脳膜炎

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/07/23 13:36:19」(JST)

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Pneumococcal infection
Classification and external resources
MeSH	D011008

Pneumococcal infection is an infection of the bacterium Streptococcus pneumoniae.

Infections

Pneumococcal meningitis

S. pneumoniae is responsible for 15–50% of all episodes of community acquired pneumonia, 30–50% of all cases of acute otitis media and a significant proportion of bacteremia and bacterial meningitis.

As estimated by WHO in 2005 it killed about 1.6 million children every year worldwide with 0.7–1 million of them being under the age of five. The majority of these deaths were in developing countries.

Pathogenesis

S. pneumoniae is normally found in the nose and throat of 5–10% of healthy adults, and 20–40% of healthy children. It can be found in higher amounts in certain environments, especially those where people are spending a great deal of time in close proximity to each other (day care centers, military barracks). It attaches to nasopharyngeal cells through interaction of bacterial surface adhesins. This normal colonization can become infectious if the organisms are carried into areas such as the Eustachian tube or nasal sinuses where it can cause otitis media and sinusitis, respectively. Pneumonia occurs if the organisms are inhaled into the lungs and not cleared (again, viral infection, or smoking-induced ciliary paralysis might be contributing factors). The organism's polysaccharide capsule makes it resistant to phagocytosis, and if there is no pre-existing anticapsular antibody, alveolar macrophages cannot adequately kill the pneumococci. The organism spreads to the blood stream (where it can cause bacteremia) and is carried to the meninges, joint spaces, bones, and peritoneal cavity, and may result in meningitis, brain abscess, septic arthritis, or osteomyelitis.

S. pneumoniae has several virulence factors, including the polysaccharide capsule mentioned earlier, that help it evade a host's immune system. It has pneumococcal surface proteins that inhibit complement-mediated opsonization, and it secretes IgA1 protease that will destroy secretory IgA produced by the body and mediates its attachment to respiratory mucosa.

The risk of pneumococcal infection is much increased in persons with impaired IgG synthesis, impaired phagocytosis, or defective clearance of pneumococci. In particular, the absence of a functional spleen, through congenital asplenia, splenectomy, or sickle-cell disease predisposes one to a more severe course of infection (Overwhelming post-splenectomy infection) and prevention measures are indicated (see asplenia).

People whose immune systems are compromised, such as those living with HIV, are also at higher risk of pneumococcal disease. In HIV patients with access to treatment, the risk of invasive pneumoccal disease is 0.2–1% per year and has a fatality rate of 8%.

There is an association between pneumococcal pneumonia and influenza. Damage to the lining of the airways (respiratory epithelium) and upper respiratory system caused by influenza may facilitate pneumococcal entry and infection.

Other risk factors include smoking, injection drug use, Hepatitis C, and COPD.

Virulence factors

S. pneumoniae expresses different virulence factors on its cell surface and inside the organism. These virulence factors contribute to some of the clinical manifestations during infection with S. pneumoniae.

• Polysaccharide capsule—prevents phagocytosis by host immune cells by inhibiting C3b opsonization of the bacterial cells
• Pneumolysin (Ply)—a 53-kDa pore-forming protein that can cause lysis of host cells and activate complement
• Autolysin (LytA)—activation of this protein lyses the bacteria releasing its internal contents (i.e., pneumolysin)
• Hydrogen peroxide—causes damage to host cells (can cause apoptosis in neuronal cells during meningitis) and has bactericidal effects against competing bacteria (Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus)
• Pili—hair-like structures that extend from the surface of many strains of S. pneumoniae. They contribute to colonization of upper respiratory tract and increase the formation of large amounts of TNF by the immune system during sepsis, raising the possibility of septic shock
• Choline binding protein A/Pneumococcal surface protein A (CbpA/PspA)—an adhesin that can interact with carbohydrates on the cell surface of pulmonary epithelial cells and can inhibit complement-mediated opsonization of pneumococci

Diagnosis

Depending on the nature of infection, an appropriate sample is collected for laboratory identification. Pneumococci are typically gram-positive, cocci, seen in pairs or chains. When cultured on blood agar plates with added optochin antibiotic disk, they show alpha-hemolytic colonies and a clear zone of inhibition around the disk meaning they're sensitive to the antibiotic. Pneumococci are also bile soluble. Just like other streptococci, they are catalase-negative. A Quellung test can identify specific capsular polysaccharides.

Pneumococcal antigen (cell wall C polysaccharide) may be detected in various body fluids. Older detection kits, based on latex agglutination, added little value above Gram staining and were occasionally false-positive. Better results are achieved with rapid immunochromatography, which has a sensitivity (identifies the cause) of 70–80% and >90% specificity (when positive identifies the actual cause) in pneumococcal infections. The test was initially validated on urine samples, but has been applied successfully to other body fluids. Chest X-rays can also be conducted to confirm an infection.

Prevention

Main article: Pneumococcal vaccine

Vaccines against Streptococcus pneumoniae are available.

Treatment

Throughout history, treatment relied primarily on β-lactam antibiotics. In the 1960s, nearly all strains of S. pneumoniae were susceptible to penicillin, but, since that time, there has been an increasing prevalence of penicillin resistance, especially in areas of high antibiotic use. A varying proportion of strains may also be resistant to cephalosporins, macrolides (such as erythromycin), tetracycline, clindamycin and the quinolones. Penicillin-resistant strains are more likely to be resistant to other antibiotics. Most isolates remain susceptible to vancomycin, though its use in a β-lactam-susceptible isolate is less desirable because of tissue distribution of the drug and concerns of development of vancomycin resistance. More advanced beta-lactam antibiotics (cephalosporins) are commonly used in combination with other drugs to treat meningitis and community-acquired pneumonia. In adults, recently developed fluoroquinolones such as levofloxacin and moxifloxacin are often used to provide empiric coverage for patients with pneumonia, but, in parts of the world where these drugs are used to treat tuberculosis, resistance has been described. Susceptibility testing should be routine, with empiric antibiotic treatment guided by resistance patterns in the community in which the organism was acquired, pending the results. There is currently debate as to how relevant the results of susceptibility testing are to clinical outcome. There is slight clinical evidence that penicillins may act synergistically with macrolides to improve outcomes.

History

In the 19th century, it was demonstrated that immunization of rabbits with killed pneumococci protected them against subsequent challenge with viable pneumococci. Serum from immunized rabbits or from humans who had recovered from pneumococcal pneumonia also conferred protection. In the 20th century, the efficacy of immunization was demonstrated in South African miners.

It was discovered that the pneumococcus's capsule made it resistant to phagocytosis, and in the 1920s it was shown that an antibody specific for capsular polysaccharide aided the killing of S. pneumoniae. In 1936, a pneumococcal capsular polysaccharide vaccine was used to abort an epidemic of pneumococcal pneumonia. In the 1940s, experiments on capsular transformation by pneumococci first identified DNA as the material that carries genetic information.

In 1900, it was recognized that different serovars of pneumococci exist, and that immunization with a given serovar did not protect against infection with other serovars. Since then over ninety serovars have been discovered, each with a unique polysaccharide capsule that can be identified by the quellung reaction. Because some of these serovars cause disease more commonly than others, it is possible to provide reasonable protection by immunizing with less than 90 serovars; the current vaccine contains 23 serovars (i.e., it is "23-valent").

The serovars are numbered according to two systems: the American system, which numbers them in the order in which they were discovered, and the Danish system, which groups them according to antigenic similarities.

References

External links

• November 2nd: World Pneumonia Day Website
• Pneumococcal Vaccine Accelerated Development and Introduction Plan

UpToDate Contents

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• 1. 成人における特定病原体により引き起こされる細菌性髄膜炎の治療treatment of bacterial meningitis caused by specific pathogens in adults [show details]
  …further declines in the incidence of pneumococcal meningitis may be seen. However, in one study that examined the impact of PCV13 on the incidence of pneumococcal meningitis in children, the number of cases …
• 2. 小児における肺炎球菌性髄膜炎pneumococcal meningitis in children [show details]
  …obtundation, coma) is more likely in children with pneumococcal meningitis compared with other causes of bacterial meningitis ; in a multicenter pneumococcal meningitis surveillance study, 11 percent of patients …
• 3. 成人における細菌性髄膜炎の疫学epidemiology of bacterial meningitis in adults [show details]
  …the incidence of pneumococcal meningitis were seen. This was shown in a study in children after introduction of PCV13 in France in which the number of cases of pneumococcal meningitis decreased by 27 percent …
• 4. 成人における細菌性髄膜炎の神経学的合併症予防のためのデキサメタゾンdexamethasone to prevent neurologic complications of bacterial meningitis in adults [show details]
  …dexamethasone use in adults with pneumococcal meningitis . Dexamethasone was initiated with or before the first dose of antibiotics in 84 percent of 357 patients with pneumococcal meningitis in 2006 to 2009 but in …
• 5. 成人の急性細菌性髄膜炎の臨床的特徴と診断clinical features and diagnosis of acute bacterial meningitis in adults [show details]
  …cerebral infarction occurred in 25 percent of episodes and in 36 percent of patients with pneumococcal meningitis . Seizures have been described in 15 to 30 percent of patients and focal neurologic deficits …

English Journal

• Lack of formyl peptide receptor 1 and 2 leads to more severe inflammation and higher mortality in mice with of pneumococcal meningitis.

• Oldekamp S1, Pscheidl S, Kress E, Soehnlein O, Jansen S, Pufe T, Wang JM, Tauber SC, Brandenburg LO.
• Immunology.Immunology.2014 Nov;143(3):447-61. doi: 10.1111/imm.12324.
• Bacterial meningitis is, despite progress in research and the development of new treatment strategies, still a cause of severe neuronal sequelae. The brain is protected from penetrating pathogens by both the blood-brain barrier and the innate immune system. The invading pathogens are recognized by p
• PMID 24863484

• Experimental study of the efficacy of daptomycin for the treatment of cephalosporin-resistant pneumococcal meningitis.

• Vivas M1, Force E2, Garrigós C2, Tubau F3, Platteel AC2, Ariza J2, Cabellos C2.
• The Journal of antimicrobial chemotherapy.J Antimicrob Chemother.2014 Nov;69(11):3020-6. doi: 10.1093/jac/dku231. Epub 2014 Jun 23.
• OBJECTIVES: To determine the efficacy of daptomycin for the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis using in vitro and in vivo methods.METHODS: In vitro killing curves were determined with clinically achievable CSF antibiotic concentrations. In a rabbit model of
• PMID 24962033

Japanese Journal

• 無脾症候群における重症細菌感染症（髄膜炎・敗血症）の検討：早期診断の重要性とワクチン予防に対する考察

• 江原 英治,村上 洋介,佐々木 赳,藤野 光洋,平野 恭悠,小澤 有希,吉田 修一朗,吉田 葉子,鈴木 嗣敏,金谷 知潤,石丸 和彦,前畠 慶人,西垣 恭一
• Pediatric Cardiology and Cardiac Surgery 30(1), 39-46, 2014
• 背景：無脾症患者は細菌感染，特に肺炎球菌に罹患しやすく，時に致死的となる．わが国では2010年より7価肺炎球菌結合型ワクチンが使用可能となり小児での予防効果が期待されている．目的：7価肺炎球菌結合型ワクチン導入前の時期での，無脾症患者における重症細菌感染症の臨床像を明らかにし，新しいワクチンを含めた今後の対策について検討すること．対象と方法：1988～2009年までに出生し，当院で治療を受けた無脾 …
• NAID 130003398235

• Spontaneous Meningitis Due to Streptococcus salivarius Subsp. salivarius: Cross-reaction in an Assay with a Rapid Diagnostic Kit that Detected Streptococcus pneumoniae Antigens

• Shirokawa Taijiro,Nakajima Jun,Hirose Kazuhito,Suzuki Hiromichi,Nagaoka Shoko,Suzuki Masatsune
• Internal Medicine 53(3), 279-282, 2014
• … salivarius occasionally causes meningitis associated with iatrogenic or traumatic events. … We herein describe a case of meningitis caused by this organism in a patient without any apparent risk factors. … In an assay of the patient's cerebrospinal fluid, cross-reaction occurred with Streptococcus pneumoniae antigen-coated latex particles in the PastorexTM Meningitis Kit. …
• NAID 130003392632

Related Links

• Pneumococcal Meningitis - Meningitis Research Foundation

Pneumococcal meningitis has the same symptoms as other forms of bacterial meningitis. Pneumococcal bacteria (Streptococcus pneumoniae) are the second biggest cause of bacterial meningitis in the UK and Ireland.

• Pneumococcal infection - Wikipedia, the free encyclopedia

Pneumococcal infection refers to an infection caused by Streptococcus pneumoniae. ... The organism spreads to the blood stream (where it can cause bacteremia) and is carried to the meninges, joint spaces, bones, and peritoneal cavity, and ...

Related Pictures

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★リンクテーブル★

リンク元	「肺炎球菌性髄膜炎」「Streptococcus pneumoniae meningitis」「肺炎球菌髄膜炎」
拡張検索	「experimental pneumococcal meningitis」
関連記事	「pneumococcal」

「肺炎球菌性髄膜炎」

　　[★]

英

pneumococcal meningitis、Streptococcus pneumoniae meningitis

関

肺炎球菌髄膜炎、実験的肺炎球菌髄膜炎

「Streptococcus pneumoniae meningitis」

　　[★]

肺炎球菌性髄膜炎

関

experimental pneumococcal meningitis、pneumococcal meningitis

「肺炎球菌髄膜炎」

　　[★]

英

pneumococcal meningitis

関

実験的肺炎球菌髄膜炎、肺炎球菌性髄膜炎

「experimental pneumococcal meningitis」

　　[★]

• 実験的肺炎球菌髄膜炎

関

pneumococcal meningitis、Streptococcus pneumoniae meningitis

「pneumococcal」

　　[★]

• adj.

• 肺炎球菌の

関

pneumococci、pneumococcus、S. pneumoniae、Streptococcus pneumoniae