#sheet (15) PART.1 Enterobacteriaceae

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1 1Page #sheet (15) PART.1 Enterobacteriaceae Made by: marah al-hiary corrected by: Mohammad al-momani date: 10/11/2016 1

2 2Page *in this lecture we will talk about a big family which is Enterobacteriaceae: this family contains a lot of species, some are normal flora and others are pathogenic. *aceae: mean family *if the enterobacteriaceae is normal flora we mostly found it in the gut and if it cause disease"pathogenic" then the disease is related to gastrointestinal tract. *the Enterobacteriaceae is gram negative rod bacteria. there are other types of gram (-) bacteria other than Enterobacteriaceae related to variation in biochemical characteristic such as" pseudomonodaceae" it is gram negative rod bacteria but it is oxidase positive while Enterobacteriaceae is oxidase negative. The largest, most heterogeneous collection of medically important gram-negative rods >40 genera and 150 species Fewer than 20 species are responsible for more than 95% of the infections (e.g: E.coli responsible for more than 90% of UTI & salmonella responsible for more than 80% of gastroenteritis ) Ubiquitous organisms, found worldwide in soil, water, and vegetation, food. Part of the normal intestinal flora ex: E.coli "the most important one" &proteus& Klebsiella & Enterobacter &acinetobacter. 30% to 35% of all septicemias, more than 70% of urinary tract infections (UTIs), and many intestinal infections *some make contamination such as serratia. *some of them may found as a normal flora in animal and some may cause pathogenic effect in animal we get it from chicken meat such as salmonella. Sometimes people are carriers for them such as proteus&enterobacter. *endogenous mean get the infection from the human itself. *exogenous mean get the infection from outside the human body (environment). *we use the ability of motile to differentiate between the species using S.S.agar Salmonella Shigella agar Salmonella motile Shigella----- nonmotile *these two type responsible for gastroenteritis and both we can cultivate in the same media and appear in the same shape we use this method to differentiate between them according to motility instead of go to biochemical method which need a lot of effort and time. 2

3 3Page Become pathogenic when they acquire virulence factor Can originate from an animal or from a human carrier, or through the endogenous spread of organisms Either nonmotile or motile with peritrichous flagella All except Klebsiella, Shigella and Yersinia are motile Do not form spores Facultative anaerobes Have simple nutritional requirements (not fastidious) *its pathogenicity can be in the CNS: E.coli "meningitis" or lower respiratory tract: Klebsiella pneumonia, E.coli or Blood stream: E.coli, Enterobacter, Klebsiella or Gastrointestinal tract: salmonella, Shigella, 5 type of E.coli, Yersinia cause plaque and Enterocolities And UTI: E.coli, proteus, Klebsiella aerogenes or other spp "may be the same genus but different species", morgonella. *also E.coli bacteria that cause UTI different from E.coli that cause lower respiratory tract infection. ferment glucose, reduce nitrate catalase positive and oxidase negative The ability to ferment lactose Escherichia, Klebsiella, Enterobacter, Citrobacter, Shigella sonni, and Serratia spp Do not ferment lactose Proteus, Salmonella, Shigella, and Yersinia spp. Some have prominent capsules such as Klebsiella. 3

4 4Page Most bacteria ferment glucose but not lactose so we use lactose. *MaCconky agar selective &differentiate agar. *Enterobacteriaceae we cultivate it in selective media macconky agar: which let gram ( ) bacteria to grow and inhibit growth of gram (+)(it differentiate between lactose fermentale which appear pink and nonfermentale which look pale). *macconky can be selective and differentiate media at the same time. *when it is a differentiate media it Distinct between the member of Enterobacteriaceae family (lactose fermental && non lactose fermental) then when we know its type.we make biochemical reaction to know more details. *Kligler ion agar* :to know which type of suger it use (glucose,sucrose,or both,..) فحص تخمر السكريات * Shigella sonni 'only from Shigella spp', and Serratia are lactose fermentation bacteria other type nonlactose fermentation. *we use swelling test or quellung test to know if the bacteria has capsules. *the color will change when we change the PH of the media. *bacteria that use lactose sure it also use glucose on the other hand bacteria that use glucose may or not use lactose (first it will use monosaccharaide glucose then disacharid ). Lactose fermentation Lactose non-fermentation Common Medically Important Enterobacteriaceae Citrobacter freundii, Citrobacter koseri Enterobacter aerogenes, Enterobacter cloacae Escherichia coli Klebsiella pneumonia cause pneumonia, Klebsiella oxytoca cause UTI Morganella morganii Proteus mirabilis, Proteus vulgaris Salmonella enterica 4

5 5Page Serratia marcescens:use transparent nutrient agar appear red. it cause UTI &spoil of food Shigella sonnei, Shigella flexneri Yersinia pestis, Yersinia enterocolitica, Yersinia pseudotuberculosis تسبب الطاعونpestis *Yersinia *cholera: yellow fever 22:00min Death: black *الطاعون يعمل نزيف بالشعيرات الموية تحت الجلد فيظهر الجسم بلون اسود *We distribute family according to DNA composition Based on clinical infections produced, Enterobacteriaceae members are divided into two categories: 1. Opportunistic pathogens normally part of the usual intestinal flora that may produce infection outside the intestine (when it change its site it becomes pathogenic) 2. Primary intestinal pathogens (fecal - oral), salmonella, shigella, and yersinia spp(it cannot be normal flora) *lipid A responsible for endotoxin. *Gram negative bacteria which has capsule it also has antigen k or vi, motile has flagella antigen (H) *we has 2 type of antigen (O)-LPS-somatic, each type has it and H if it is motile such as salmonella has both. Escherichia coli The most common gram-negative rods isolated from patients with Sepsis Responsible for causing more than 80% of all community-acquired UTIs Gastroenteritis in developing countries 5

6 Most infections are Endogenous especially in E.coli. Diseases Min 30:00 6Page Bacteremia (most commonly isolated gram-negative rod) anus UT urethra bladder ureter kidney blood "bacteremia" Urinary tract infection (most common cause of bacterial UTIs); limited to bladder (cystitis) or can spread to kidneys (pyelonephritis) or prostate (prostatitis) E.coli (usually the infection happen in the lower part ) سهل عالج Lower UT مقارنة ب Upper UT At least five different pathogenic groups cause Gastroenteritis (EPEC, ETEC, EHEC, EIEC, EAEC); most cause diseases in developing countries, although EHEC is an important cause of hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) (there is RBC with urine) Neonatal meningitis (usually with strains carrying the K1 capsular antigen) Intraabdominal infections (associated with intestinal perforation Gastroenteritis ETEC "enterotoxigenic E.coli": Traveler's diarrhea; infant diarrhea in developing countries (toxin) watery diarrhea, vomiting, cramps, nausea, low-grade fever Plasmid-mediated, heat-stable (ST) and/or heat-labile (LT) enterotoxins that stimulate hypersecretion of fluids and electrolytes *this activate adenelel cyclase which convert ATP CAMP &GTP CGMP this cause secretion of fluid and decrease reabsorbtion of Na this will cause diarrhea. *LT act on ATP *ST act on GTP EPEC "enteropathogenic E.coli": Infant diarrhea in underdeveloped countries; watery diarrhea and vomiting, nonbloody stools(responsible for 2 type of enterotoxin the first one heat stable the second is heat labial toxinboth stimuli secretion of fluid and ----) )After attachment, there is loss of microvilli (effacement 6

7 villus 7Page EAEC "enteroagregative E.coli": Infant diarrhea in underdeveloped countries; traveler's diarrhea, persistent or chronic diarrhea Plasmid-mediated aggregative adherence of rods يزيد افراز السوائل ويقلل امتصاص االيونات (EAST) Enteroaggregative heat stable toxin *invasidness means bacteria act on blood cell *diarrhea related to lose the microvilli their ability of absorption not to toxin cause.(make cup) EHEC "enterohemorrhagic :خطيرة" E.coli Initial watery diarrhea, followed by grossly bloody diarrhea (hemorrhagic colitis) with abdominal cramps; may progress to hemolytic uremic syndrome (HUS) Mediated by cytotoxic Shiga toxins "like Shigella, which disrupt protein synthesis( lesions ) cause necrosis in intestine it is very dangerous Destruction of intestinal microvillus resulting in decreased absorption EIEC "enteroinvasive E.coli": fever, cramping, watery diarrhea; may progress to dysentery with scant, bloody stools"from RBC", fever, severe inflammation. Plasmid-mediated invasion and destruction of epithelial cells Escherichia coli-uti Colon Contaminate Urethra ascending to the bladder and may migrate to kidney or prostate UTIs: adhesins (primarily P pili) and hemolysin Min 46:00 Escherichia coli-neonatal Meningitis E.coli and group B - Streptococci major CNS pathogens K1 capsular antigen help in its pathogenicity Commonly present in the GIS "in GIT" Escherichia coli-septicemia May be originated from UT or GIS "in GIT" Mortality is high 7