Ch. 19 Enterobacteriaceae

biochemical characteristics

Differentation of each genus of Enterobacteriaceae and definitive identification of species are based on ___________ ____________.

rose spots

Enteric Fevers (typhoid fevers)------_____ ______ (blanching, rose colored papules around the perumbilical region) appear during the second week of fever.

Typhoid fever

Enteric fever caused by Salmonella Typhi is known as _____ _____.

fecal-oral

Enteroinvasive Escherchia coli(EIEC)----direct transmission of EIEC from person to person via the ___ ____ route has been reported.

traveler's diarrhea

ETEC (Enterotoxigenic Escherrichia coli)----ETEC diarrhea is the most common cause of diarrheal disease, sometimes referred to as ______ ______.

Gallbladder

Enteric Fevers (typhoid fever)------The _____ becomes the foci of long-term carriage of the organism.

oxidase test SBA plate

Enterobacteriacea------Gram-negative isolates, especially NLFs, should be tested for cytochrome oxidase production. The _______ test should always be performed using young growth from an ___ plate.

K antigen

Enterobacteriaceae----- or capsular antigen, this is a heat labile polysaccharide found only in certain encapsulated species.

O antigen

Enterobacteriaceae------ somatic antigen, this is a heat stabile antigen located on the cell wall.

site of origin

Enterobacteriaceae--------To determine the clinical significance of the isolate, the microbiologist must consider the _____ __ _______.

H antigen

Enterobacteriaceae------flagellar antigen- heat labile antigen found on the surface of flagella, structures responsible for motility.

Vi antigen

Enterobacteriaceae------or salmonella enterica subsp. enterica serotype Typhi

Plesiomonas shigelloides

Enterobacteriaceae-----All members of the family are oxidase negative except for _______ _____.

gastroenteritis

Enterotoxin produced by certain salmonella strains that cause _________ has been implicated as a significant virulence factor.

UTIs

Escherichia coli is widely recognized as the most common cause of _____ in humans.

cold blooded animals rodents and birds

Many salmonella serotypes are typically found in _____ ______ _____ as well as ______ and _______, which serve as natural hosts.

lactose and sucrose color change pH

Media contains usually one or more carbohydrates, such as ____ and ______, Fermentation is indicated by the ____ ____ on the medium., which results from a drop in ___. (Enterobacteriacae)

self-limiting

Most cases of Salmonella gastroenteritis are ______ ______.

HE, XLD, MAC, SMAC (e-coli 0157;H7)

Most clinical microbiologists inoculate stool samples on highly selective media, such as ___ or ___ agars, in addition to regular ____ and ____ agar for E. coli 0157:H7.

lysine decarboxylase red colonies with black centers

NLF species such as Salmonella enterica, which produces ______ _____, produce ____ colonies with _____ ______.

Salmonella Shigella Yersinia E. coli 0157:H7 Aeromonas Campylobacter Vibrio Plesiomonas Shigelloides

Name the enteric pathogens (8)

Proteus

None of the members of this tribe ferment lactose.

mauve-colored

On CHROMagar Salmonella, Salmonella isolates will produce _____-______ colonies.

yellow (lactose fermenting) green (NLFs)

On HE agar, lactose fementing species produce ______ colonies, whereas NLFs such as Shigella spp. produce _____ colonies.

indole and ornithine decarboxylase tests P. mirabilis

P. mirabilis is differentiated from P. vulgaris by the ______ and _____ _____ tests; _ _______ does not produce indole from tryptophan and is ornithine positive.

negative hydrogen sulfide

Salmonella---- In most cases they do not ferment lactose. They are ______ for indole, the Voges-Proskauer test, phenylalanine deaminase, and urease. Most produce _____ _______.

Mac clear colorless black centers hydrogen sulfide production.

Salmonella----On Selective and differential media used primarily to isolate enteric pathogens, such as ___, salmonellae produce _____, _____, non lactose forming colonies; colonies with ____ ____ if seen if the media ( HE or XLD) contain indicators for _____ ______ production.

brick red color

Serratia spp. has a ____ ____ color.

pink to red pigment

Serratia-----S. marcescens, S. rubidaea, and S. plymuthica often produce a characteristic ______ to _____ pigment.

serologic grouping

Shigella spp. are also divided into four major O antigen grouped and must be identifiable by ______ ______.

hydrogen sulfide (black)

Shigella spp. do no produce _____ ____.

mucus and leukocytes colonic tissues

Shigellosis------Bloody stools containing _____ and numerous ____ follow the watery diarrhea, as the organisms invade the _____ ____ and cause an inflammatory reaction.

MAC agar containing sorbitol (SMAC)

Stool culture for E. coli 0157-H7 may be performed using _____ ___ containing _______ (____) instead of lactose.

respiratory transmission

Subsequent epidemic outbreaks may arise from the ______ ______ of the organisms of Y. pestis.

Hemolytic Uremic Syndrome (HUS)

The EHEC strain serotyping 0157-H7 has been associated with hemorrhagic diarrhea, colitis, and _________ __________ ____________ (_____)

gastrointestinal tract salmonella, shigella, and Yersinia

The Enterobacteriaceae, with a few exceptions, share a common niche, they reside in the ________ _____, except for (3)

somatic O and flagellar H Vi

The _____ ___ antigens and _______ ___ antigens are the primary antigenic structures used in serologic grouping of salmonellae. A few strains may possess capsular (K) antigens, designated ___ antigen.

Bloody diarrhea

The classic illness caused by EHEC produces watery diarrhea that progresses to _____ _______with abdominal cramps, a low grade fever, or an absence of a fever.

24-48 hours

The initial symptoms of Shigellosis are marked by a high fever, chills, abdominal cramps, and pain accompanied by tenemus, appear approximately __--_____ hours are ingestion of the organisms.

S. enterica, Shigella spp., and Yersinia

The primary pathogens of Enterobacteriaceae are (3), that is, they are not present as commensal biota in the GI tract of humans.

burnt chocolate

The swarmer cells also produce the distinct odor associated with Proteus colonies, sometimes described as ______ ______.

TSI agar or Kligler iron agar (KIA) Simmons citrate Sulfide, indole,motility (SIM)

The traditional biochemical tests to perform for identification include the following: **_____ agar or ______ ____ agar (___) to determine glucose and lactose or sucrose, utilization, and hydrogen sulfide production. ** _______ _______ to determine the ability to use citrate as the sole carbon source. **______,_______,_____ (____) or motility, indole, and orthinine (MIO) media (pg450)

Escherichia coli, Klebsiella pneumonia, and proteus mirabilis

There are many genera and species of Enerobacteriaceae, however clinical isolates in general acute-care facilities consist primarily og what 3?

Y. pestis

__ ____ is the causative agent of plague, a disease primarily of rodents transmitted to humans by fleas.

Shigella spp.

______ spp., are not members if the normal GI microbiota, and all ______ _____ can cause bacillary dysentery.

typhoid fever

________ ________, is the most severe form of enteric fever caused by salmonella serotype Typhi.

mucoid appearance

On MAC, K. pneumoniae has a ________ appearance. Pg 435 figure 19-3

swarming nonselective media such as SBA

P. mirabilis and P. Vulgaris produce _______ colonies on _______ media, such as _____.

hemorrhagic diarrhea and colitis

(EHEC) 0157:H7 strain of E coli was first recognized during an outbreak of ________ ________ and ______.

motile adhesive fimbriae sex pili O,H, and K antigens

4 characteristics of E-coli

plasmid-mediated extended-spectrum B-lactamases (ESBLs)

An increasing number of E. coli, K. pneumoniae, and K, oxytoca clinical strains produce, ___ ___ __ ___ ___, which can inactivate extended spectrum cephalosporin's, penicillin's, and aztreonam.

low infective

Because of the ____ _____ dose required to produce the disease, shigellosis is highly communicable.

hydrogen sulfide (black) urea

Both species (P. mirabilis and P. vulgaris) produce _____ _____ and hydrolyze _____.

gram-negative non-spore forming facutatively anaerobic bacilli coccobacilli or straight rods

Characteristics of Enterobacteriaceae (4)

yellow colonies with black centers

Citrobacter freundii usually produces _____ colonies with _____ _____.

nonlactose fermenters (NLFs) clear or colorless and translucent on MAC

Fecal pathogens are generally ____ _______ (___). These organisms appear as ____ or ________ and _______ colonies on ____ agar.

10^6

Gastroenteritis (salmonella caused)------The infective dose necessary to initiate the disease, ___ bacteria, is higher than that required for shigellosis.

blackening

HE and XLD agars contain sodium thiosulfate and ferric ammonium citrate, which produce _____ of H2S-producing colonies. (Enterobacteriaceae)

low platelet count hemolytic anemia kidney failure

HUS (hemolytic Uremic Syndrome) is characterized by what (3)

polysaccharide capsule phagocytosis

K. pneumoniae is the most commonly isolated species and has the distinct feature of possessing a __________ _________. This offers the organism protection against ________.

respiratory, urine, and blood blue-violet

Kluyvera-----They have been found in ______,______, and ____ cultures and may produce a _____-______ pigment.

O-antigen H antigen K antigen Vi antigen

Many members of Enterobacteriaceae family possess antigens that can be used in the identification of different serologic groups. What are these antigens?

slowly ferments lactose delayed positive fermentation of lactose

S. sonnei is unique in its ability to decarbocylate ornithine; it ____ _____ _____; that is, one sees a ______ _____ _____ of ______.

poultry, eggs

Salmonella and Shigella organisms produce GI illnesses in humans. Humans acquire the infection by ingesting organisms in contaminated animal food products or insufficiently cooked _____, milk, _____ and dairy products.

gram-negative

Salmonella organisms are gram-______, facultatively anaerobic bacilli that morphologically resemble other enteric bacteria.

lactose slowly

Serratia spp. ferment ______ ______.

8-36 hours

They symptoms of intestinal salmonellosis, which may appear ____ to ____ hours after ingestion of contaminated food, include nausea, vomiting, fever, and chills accompanied by watery diarrhea and abdominal pain.

P. mirabilis and P. vulgaris

Two species of Proteus:

cold 25 C

Y. enterocolitica grows better with _____ enrichment, and motility is clearly noted at ____ C.

bipolar

Y. enterocolitica morphology resmembles other Yersinia spp., which appear as gram-negative coccibaccilli with ________ staining.

packed RBCs

Y. enterocolitica sepsis is associated with the transfusion of contaminated ____ ________ have been reported.

household pets

Y. enterocolitica-------This infection can be acquired from contact with ______ ______.

blood

Y. enterocolitica-------stools may contain ______.

appendicitis

Y. enterocoliticia produces an infection that mimics ___________-.

Class A Bioterrorism Agents

Y. pestis is a ______ ___ _______ ________.

Gram-negative, short, plump bacillis

Y. pestis is a gram-______, ______, ______, ________.

bilpolar staining (safety pin)

Y. pestis shows ______ _______.

rodents guinea pigs

Yersinia psuedotuberculosis, like Y. pestis, is a pathogen primarily of ______, particularly _____ _____.

blood, mucus, and pus

Dysentery was characterized by the presence of ______,_____, and ____ in the stool.

Shiga toxigenic E. coli (STEC)

E coli strains that produce verotoxin I and vertoxin II-----they are also called _____ _____ _______ (_____)

B-hemolytic

E-coli are ___-________.

lactose positive (pink)

E-coli has a distinctive morphology. It usually presents as ____ _____ (_____) colony with a surrounding are of precipitated bile salts on MAC agar.

green metallic sheen

E-coli on EMB agar, presents with a _____ ____ ______.

colorless

E. coli 0157:H7 appears ______ on SMAC agar.

48 hours

E. coli 0157:H7 does not ferment sorbitol in _____ ______, a characteristic that differentiates it from most other E. coli strains.

undercooked hamburgers

EHEC-(0157-H7)-------Processed meats, such as _______ ______ served at fast food restaurants, unpasteurized dairy products and apple cider, bean sprouts., and spinach have all been implicated in the spread of infection.

leukocytes

EHEC-----the stool contains no _________, which distinguishes it from dysentery caused by shigella spp. or EIEC infections.