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Acute infectious diarrheal disease

´Ù¾çÇÑ ÀÓ»óÀû Áõ»óÀÌ ÀÖÀ¸¸ç virus, bacteria, parasite¸¦ Æ÷ÇÔÇÑ ´Ù¾çÇÑ °¨¿°ÀÎÀÚµéÀÌ

°ü¿©ÇÑ´Ù.

1. Pathogenic mechanism

1) inoculum size

Salmonella, Vibrio cholera : 105-108°³

Shigella, Giardia lamblia, Entamoeba : 10-100°³ Á¤µµ·Îµµ infectionÀ» ÀÏÀ¸Å²´Ù.

* transmission

Shigella, Entamoeba, Giardia : person to person

Salmonella : food

2) Adherence

±ÕµéÀº º´À» ÀÏÀ¸Å°±â À§ÇØ Á¤»ó À§Á¡¸·¿¡ ºÎÂøÇØ¾ß Çϴµ¥ À̶§ normal flora¿Í °æÀïÇϸç

Áõ½ÄÇÑ´Ù. ¼¼±ÕÀº Àå³»¼¼Æ÷¿¡ ºÎÂøÇÏ´Â specific cell-surface proteinÀ» ºÐºñÇÑ´Ù.

¿¹> V. cholera : specific surface adhesin(toxin-coregulated pilus, ´Ù¸¥ accessory

colonization factors)À¸·Î ¼ÒÀå¼¼Æ÷ÀÇ brush border¿¡ ºÎÂøÇÑ´Ù.

ETEC : adherence protein(colonization factor Ag) ºÐºñ

EPEC, EHEC : Àå³» Á¤¸·¼¼Æ÷ÀÇ brush border¿¡ ºÎÂøÇÏ´Â virulence determinant»ý»ê

3) toxin production

¨ç enterotoxin : secretory mxÀ» ÅëÇÏ¿© watery diarrheaÀ¯¹ß

* prototype : cholera toxin

(A subunit : toxinÀÇ enzymatic activity, B subunit : enterocyte surface receptor¿¡

°áÇÕ)

ETEC : heat-labile enterotoxin(LT)»ý»ê-> secretory diarrheaÀ¯¹ß

¨è cytotoxin : mucosal cellÆÄ±«

-> inflammatory diarrhea, bloody diarrhea(dysenteryÀ¯¹ß)

S. dysentery(shiga toxin), V. parahemolyticus, C. difficile, EHEC(O157:H7)(shiga-like

toxin)

¨é neurotoxin : CNS, PNS¿¡ ÀÛ¿ë

Staphylococcal, Bacillus cereus toxin -> CNS¿¡ ÀÛ¿ëÇÏ¿© vomitingÀ¯¹ß

¨ê exotoxin : Shigella dysenteriae type 1 -> exotoxin»ý»ê -> enterotoxin, cytotoxic

activity

4) Invasion

Shigella, EIEC -> mucosal epithelial cell invasion

-> intraepithelial multiplication

subsequent spread to adjacent cell

Salmonella : bowel mucosa invasionÇÏÁö¸¸ enterocyte¸¦ ÆÄ±«Çϰųª dysentery¸¦

ÀÏÀ¸Å°Áö ¾Ê´Â´Ù.

S. typhi, Y. enterocolitica -> intestinal mucosa penetration

-> Peyer's patch, lymph node¿¡¼­ Áõ½Ä

-> Ç÷¾×À» Ÿ°í ÆÛÁü

-> enteric fever, headahce, relative bradycardia, abd pain, splenomegaly,

leucopenia

2. Host defenses

1) Normal flora : 99%ÀÌ»óÀÌ anaerobic bacteria

acidic pH, volatile fatty acid»ý¼ºÇÏ¿© colonizationÀ» ¸øÇϵµ·Ï ÇÑ´Ù.

2) Gastric acid : acidic pH of stomach = important barrier

gastric surgeryÈÄ Salmonella, shigella, G. lamblia, ¸¹Àº helminthsµîÀÇ °¨¿°ÀÌ

Áõ°¡ÇÑ´Ù.

antacid, H2 blocker·Î neuralization -> enteric colonization risk¡è

rotavirus : acidity¿¡µµ »ýÁ¸

3) intestinal motility : major mx

4) immunity : cell-mediated immunity, humoral immunity ¸ðµÎ Áß¿ä

3. Lab

pathogenic E. coli : routine culture·Î normal fecal¿Í ±¸º°¡¿

LT, STÀÇ special test : ´ëºÎºÐÀÇ lab¿¡¼­ À¯¿ë¡¿

cholera : TCBS agar

salmonella & shigella : MacConkey's agar

Tab 128-1 Acute diarrhea¸¦ ÀÏÀ¸Å°´Â pathogen

1) Noninflammatory(Enterotoxin) - proximal small bowel

- watery diarrhea

- stool WBC(-)

V. cholerae, ETEC, C. perfringens, Bacillus cereus, S. aureus

Aeromonas hydrophila, Plesiomona shigellosis, Rotavirusµî,

Giardia lamblia, Cryptosporidium

2) Inflammatory(Invasion or cytotoxin) - colon or distal small bowel

- dysentery or inflammatory diarrhea

- stool neutrophil(+)

Shigella, Salmonella, C. jejuni, EHEC, EIEC, Y. enterocolitica,

V. parahemolyticus, C. difficile, E. histolytica

3) Penetrating - distal small bowel

- enteric fever

- stool monocyte(+)

S. typhi, Y. enterocolitica

Tab 128-2 Bacterial food poisoning

1-6 hr incubation : S. aureus, B. cereus

8-16hr : C. perfringens, B. cererus

> 16hr : V. cholerae, ETEC, Salmonella, Shigella, V. parahemolyticus