衷醫行樂

Salmonella (沙門氏桿菌) (要和Shigella比較)：侵犯血液淋巴(因為有鞭毛)

只有人有，在小腸

• attach to the mucosa of small intestine and invade into the M (microfold) cells
• type III secretion systems

invasion into the intestinal mucosa (Salmonella pathogenicity island 1 [SPI-1]) and subsequent systemic disease (SPI-2)

• intracellular replication in the phagosome
• Protected from stomach acids and the acid pH of the phagosome by an acid tolerance response (ATR) gene
• eating contaminated food
• Direct fecal-oral (adapted to human)

• Highly adapted to humans can survive in the gallbladder (膽囊)
• Replicate after being transported to the liver, spleen, and bone marrow
• Typhoid fever (傷寒) (在 developing country) (Typhoid Mary)
• Enteric fever (腸熱症)

S. typhi produce a febrile illness called typhoid fever (傷寒)

Shigella：少量即可致病，fecal-oral，沒有鞭毛(不侵犯血液淋巴)

只有人有，在大腸

• S. sonnei is the most common cause of shigellosis in the industrial world
• S. flexneri is the most common cause in developing countries
• invade the M cells
• survive phagocytosis by inducing programmed cell death (apoptosis)

S. dysenteriae (痢疾志賀氏桿菌) produce an exotoxin, Shiga toxin

Shiga toxin has one A subunit and five B subunits (Like the toxin produced by EHEC)

• damage to the intestinal epithelium and glomerular endothelial cells (resulting in HUS)

HUS(Hemolytic uremic syndrome)àShigella、EHEC 最嚴重

• Humans are only reservoir for Shigella

Yersinia.pestis：

• with a protein capsule, resist to phagocytic killing
• highly virulent pathogen that causes systemic disease with a high mortality rate
• zoonotic infection：flea bites (鼠蚤叮咬)
• inhalation of infectious aerosols (具感染性的口沫)

causes bubonic plague 腺鼠疫 (most common) and pulmonary plague肺鼠疫

Cold enrichment culture (寒冷增值法)

– Prolonged storage at 4°C can selectively enhance isolation

Klebsiella.pneumonia：

重要àcommunity-acquired，COPD

• Klebsiella.pneumonia primary liver abscess (KLA)
• K1、K2 capsular serotypes à biofilm

Proteus.mirabilis：

有很多ureaseà產生CO2，造成PH值上升à所以會有 renal stone ( kidney stone)

One minute exam

• 下列有關腸桿菌科菌種病原性決定因素的敘述，何者錯誤？

(A)有些腸桿菌會產生腸毒素，腸毒素為內毒素一種，可引起腹瀉

(B)內毒素的產生會引起病人發燒，甚至休克而死亡

(C)志賀氏菌、傷寒沙門氏桿菌均具有穿透腸道表皮層的能力

(D)腸內桿菌如克雷伯氏菌具有莢膜，能抵抗吞噬作用

Ans：(A)

• 大腸桿菌（Escherichia coli）所引起各種不同型態的腹瀉症（ diarrhea）主要取決於：

(A)共同感染的其他細菌之種類

(B)此菌的體表抗原性

(C)宿主的免疫力

(D)此菌所產生的毒力因素

Ans:(D)

• 腸內桿菌科中比較容易感染呼吸道，造成鼻病及肺炎的細菌屬於下列何種細菌？

(A)克雷白氏桿菌屬(Klebsiella)

(B)志賀氏桿菌屬(Shigella)

(C)變形桿菌屬(Proteus)

(D)耶爾辛氏桿菌屬(Yersinia)

Ans:(A)

• 以下有關鼠疫之敘述，何者正確？

(A)肺鼠疫主要由鼠蚤之叮咬所引起

(B)腺鼠疫主要由吸入含鼠疫桿菌之飛沫所引起

(C)敗血性鼠疫乃因鼠疫桿菌由淋巴系統進入血流後所引起

(D)人類、鼠、蚤皆為鼠疫桿菌之自然宿主

Ans：(C)