MICROBIOLOGY PPT LECTURE NOTES | Karya Tulis Ilmiah

(1)

ENTEROBACTERIACEAE

(2)

Morphology & Identification

 Gram-negative non-spore forming rods. When motile, by perit

richous flagella.

 Primarily normal flora of gastrointestinal tract. E. coli>Klebsi

ella>Proteus>Enterobacter

 Free living, also transient colonizers of skin.

 Facultative anaerobes: mixed acid fermentation

 All ferment glucose; all reduce nitrates to nitrites; all oxidase

negative.

 Lactose fermentation: normal flora positive and pathogens ne

gative.

 Primary isolation media include eosin-methylene-blue (EMB)

and MacConkey agar.

 Differential selective media for specific organisms including dy

(3)

Classification

~29 genera, over 100 species.

~29 genera, over 100 species.

(4)

Antigenic

Structure

– _{Most are motile by peritrichous flagella --}_{Most are motile by peritrichous flagella --}_H_H_antig_antig

ens.

– Capsule – _{Capsule –} KK antigen (antigen ( ViVi for Salmonella).for Salmonella).

– _{Cell envelope (wall)}_{Cell envelope (wall)}

– LPS (endotoxin) –_{LPS (endotoxin) –} OO antigen. antigen.

– _{various outer membrane proteins.}_{various outer membrane proteins.}

– _{Pili - various antigen types, some encoded by plas}_{Pili - various antigen types, some encoded by plas}

mids

(5)

鞭鞭鞭鞭鞭 H 鞭

(6)

– _septicemia,_septicemia, – pneumonia, _pneumonia,

– _meningitis_meningitis

– _{urinary tract infections}_{urinary tract infections}

Citrobacter Enterobacter Escherichia Hafnia Morganella Providencia Serratia

Opportunistic diseases

(7)

Enterobacteriaceae

:

gastrointestinal diseases

– _{Escherichia coli}_{Escherichia coli} – _Salmonella_Salmonella

– _Shigella_Shigella

(8)

• Histocompatibility antigen (HLA) B27_{Histocompatibility antigen (HLA) B27}

– _{Enterobacteriaceae}

*_Salmonella *_Shigella

*_Yersinia

–_Not_Not _{Enterobacteriaceae}_{Enterobacteriaceae} *Campylobacter_{Campylobacter}

*_Chlamydia_Chlamydia

(9)

• _{community acquired}

• otherwise healthy people

– _{Klebsiella pneumoniae}

*_{respiratory diseases} * prominent capsule

–urinary tract infection

–_{fecal contamination} *_{E. coli}

*Proteus

– _{urease (degrades urea)}_{urease (degrades urea)} – _{alkaline urine}_{alkaline urine}

Enterobacteriaceae

(10)

Enterobacteriaceae

•

gram negative facultative anaerobic rods

–

(11)

•

E. coli

–

lactose positive

–

not usually identified

–

lactose positive sp. common, healthy intestine

•

Shigella, Salmonella,Yersinia

–

lactose negative

–

identified

Feces

(12)

• _{other sites}_{other sites}

– identified biochemicallyidentified biochemically

Enterobacteriaceae

(13)

Serotypes



reference laboratory

–

antigens

O (lipopolysaccharide) O (lipopolysaccharide)

H (flagellar) H (flagellar)

(14)

Escherichia coli

(15)

Escherichia coli

 Toxins: two types of enterotoxin; Shiga-type

toxin; Enteroaggregative ST-like toxin; Hemolysin s; Endotoxin

 Type III secretion system

 Adhesions –colonization factors ; both pili or fim

briae ;non-fimbrial factors involved in attachmen t. There are at least 21 different types of adhesion s.

 Virulence factors that protect the bacteria from h

ost defenses: Capsule/Iron capturing ability (enter ochelin)

(16)

E. coli

fimbriae

mannose

mannose

Type 1

• galactose _galactose

– _glycolipids_glycolipids – _{glycoproteins}_{glycoproteins}

P

(17)

E.coli-urinary tract infection

(18)

E.coli-Meningitis and Sepsis



Neonatal meningitis – is the leading cause

of neonatal meningitis and septicemia

with a high mortality rate. Usually

(19)

Enteropathogenic

E. coli



fever



infant

diarrhea



vomiting



nausea



non-bloody stools



Destruction of surface microvilli

1.

loose attachment mediated by bundle f

orming pili (Bfp);

2.

Stimulation of intracellular calcium lev

el;

(20)

Enterotoxigenic

E. coli



A

watery diarrhea, nausea, abdominal cr

amps and low-grade fever for 1-5 days.



T

ravellers diarrhea

and

diarrhea in child

ren in developing countries



Transmission is via contaminated food or

water.

(21)

Enterotoxigenic

E. coli



diarrhea like cholera



milder

(22)

Enterotoxigenic

E. coli

 Heat labile toxin_{Heat labile toxin}

– like choleragen_{like choleragen}

– Adenyl cyclase activated _{Adenyl cyclase activated}

– _{cyclic AMP}_{cyclic AMP}

– secretion water/ions_{secretion water/ions}

 Heat stable toxin_{Heat stable toxin}

– _{Guanylate cyclase activated}_{Guanylate cyclase activated} – _{cyclic GMP}_{cyclic GMP}

(23)

(24)

E.coli-E.coli-

Enteroinvasive (EIEC)

 The organism attaches to the intestinal mucosa v

ia pili

 Outer membrane proteins are involved in direct

penetration, invasion of the intestinal cells, and d estruction of the intestinal mucosa.

 There is lateral movement of the organism from

one cell to adjacent cells.

 Symptoms include fever,severe abdominal cramp

s, malaise, and watery diarrhea followed by scant y stools containing blood, mucous, and pus.

(25)

Enteroinvasive

E. coli

(EI

EC

)



Dysentery

-

resembles shigellosis

(26)

E.coli-E.coli-

c. Enteropathogenic (EPEC)

 Malaise and low grade fever_{diarrhea, vomiting,}

nausea, non-bloody stools

 Bundle forming pili are involved in attachment

to the intestinal mucosa.

 This leads to changes in signal transduction in t

he cells, effacement of the microvilli, and to inti mate attachment via a non-fimbrial adhesion c alled intimin.

 This is a problem mainly in hospitalized infants

(27)

(28)

E.coli-E.coli-

d. Enterohemorrhagic (EHEC)

 Hemorrhagic

– _{bloody, copious diarrhea} – _{few leukocytes}

– _afebrile

 hemolytic-uremic syndrome

– _{hemolytic anemia}

(29)

Enterohemorrhagic

E. coli

•

Usually O157:H7

(30)

Enterohemorrhagic

E. coli



Vero toxin

–

“

shiga-like”



Hemolysins



younger than 5 year

(31)

Enteroaggregative

E. c

oli

肠肠肠肠肠肠肠肠



a cause of persistent, watery diarrhea with vo

miting and dehydration in infants.



That is autoagglutination in a ‘stacked brick’

arrangement.



the bacteria adheres to the intestinal mucosa

and elaborates enterotoxins (enteroaggregativ

e heat-stable toxin, EAST).



The result is mucosal damage, secretion of la

(32)

E.coli-E.coli-

Enteroaggregative (EAggE

C)

 Mucous associated autoagglutinins cause aggre

gation of the bacteria at the cell surface and res ult in the formation of a mucous biofilm.

 The organisms attach via pili and liberate a cyt

otoxin distinct from, but similar to the ST and LT enterotoxins liberated by ETEC.

 Symptoms incluse watery diarrhea, vomiting, d

(33)

(34)

Summary of

E.coli

str

ains that cause gastr

oenteritis.

(35)

Sanitary significance



Totoal bacterial number: number of bact

eria contained per ml or gm of the sampl

e; the standard of drinking water is less t

han 100.



Coliform bacteria index: the number of c

oliform bacteria detected out per 1000 m

l sample; the standard of drinking water

is less than 3

(36)

Escherichia coli

 _Genetically_{E. coli}_and_Shigella_{are genetically highly closely related. For practical reasons (primarily to avoid confusion)}

they are not placed in the same genus. Not surprisingly there is a lot of overlap between diseases caused by the two organi sms.

 _{1) Enteropathogenic}_{E. coli}_{(EPEC). Certain serotypes are commonly found associated with infant diarrhea. The use of ge}

ne probes has confirmed these strains as different from other groups listed below. There is a characteristic morphological l esion with destruction of microvilli without invasion of the organism that suggests adhesion is important. Clinically one o bserves fever, diarrhea, vomiting and nausea usually with non-bloody stools.

 _{2) Enterotoxigenic}_{E. coli}_{(ETEC) produce diarrhea resembling cholera but much milder in degree. Also cause "traveler’s}

diarrhea". Two types of plasmid-encoded toxins are produced. a) Heat labile toxins which are similar to choleragen (see c holera section below). Adenyl cyclase is activated with production of cyclic AMP and increased secretion of water and ion s. b) Heat stable toxins; guanylate cyclase is activated which inhibits ionic and water uptake from the gut lumen. Watery d iarrhea, fever and nausea result in both cases.

 _{3) Enteroinvasive}_{E. coli}_{(EIEC) produce dysentery (indistinguishable clinically from shigellosis, see bacillary dysentery}

below).

 _{4) Enterohemorrhagic}_{E. coli}_{(EHEC). These are usually serotype O157: H7. These organisms can produce a hemorrhagic}

colitis (characterized by bloody and copious diarrhea with few leukocytes in afebrile patients). Outbreaks are often caused by contaminated hamburger meat. The organisms can disseminate into the bloodstream producing systemic hemolytic-ure mic syndrome (hemolytic anemia, thrombocytopenia and kidney failure). Production of Vero toxin (biochemically similar to shiga toxin thus also known as "shiga-like") is highly associated with this group of organisms; encoded by a phage. He molysins (plasmid encoded) are also important in pathogenesis.

 _{As noted above, there are at least 4 etiologically distinct diseases. However, in the diagnostic laboratory generally the gro}

(37)

Shigella

(38)

Shigella



S. flexneri, S. boydii, S. sonnei, S.

dysenteriae

–

bacillary dysentery

–

shigellosis

(39)

Genral

features



Pili.



Most strains can not ferment lactos

e; S. sonnei can slowly_ ferment lac

tose.

(40)

Shigellosis



within 2-3 days

(41)

Shiga toxin



enterotoxic



cytotoxic



inhibits protein synthesis

(42)

Shigella

attachment and penetration

 W_Within 2-3 days_{ithin 2-3 days}

 E_Epithelial cell damag_{pithelial cell damag}

e

(43)

Clinical significance



man only "reservoir"



mostly young children

–

fecal to oral contact

–

children to adults

(44)

Clinical significance

 The infective dose required to cause infection is ver

y low (10-200 organisms).

 There is an incubation of 1-7 days followed by fever

, cramping, abdominal pain, and watery diarrhea (due to the toxin)for 1-3 days.

 This may be followed by frequent, scant stools with

blood, mucous, and pus (due to invasion of intestina l mucosa).

 Is is rare for the organism to disseminate.

 The severity of the disease depends upon the specie

(45)

Immunity

(46)

Diagnosis of Shigella infection



Specimen: stool.



Culture and Identification



Quick immunological methods:

(47)

Prevention



streptomycin dependent (SD)

(48)

Treating shigellosis



manage dehydration



patients respond to antibiotics ,

P

roblem of drug-resistance

(49)

Shigella

 _{Shigella (4 species; S. flexneri, S. boydii, S. sonnei, S. dysenteriae) all cause bac}

illary dysentery or shigellosis, (bloody feces associated with intestinal pain). T he organism invades the epithelial lining layer, but does not penetrate. Usually , within 2-3 days, dysentery results from bacteria damaging the epithelium lini ng layers of the intestine often with release of mucus and blood (found in the f eces) and attraction of leukocytes (also found in the feces as "pus"). Shiga toxi n (chromosomally encoded) is neurotoxic, enterotoxic and cytotoxic plays a ro le. The toxin inhibits protein synthesis (acting on the 80S ribosome and lysing 28S rRNA). This is primarily a disease of young children occurring by fecal-o ral contact. Adults can catch this disease from children. However it can be tra nsmitted by infected adult food handlers, contaminating food. The source in e ach case is unwashed hands. Man is the only "reservoir".

 Patients with severe dysentery are usually treated with antibiotics (e.g. ampici

(50)

Salmonella

 Salmonellosis may pres

(51)

The antigenic structures of salmonellae

The antigenic structures of salmonellae

used in serologic typing

(52)

Salmonella



2000 antigenic "types”



disease category

–

S. enteritidis

– many serotypes_{many serotypes}

(53)

Virulence factors

 Endotoxin – may play a role in intracellular survival  Capsule (for S. typhi and some strains of S. paratyphi)  Adhesions – both fimbrial and non-fimbrial

 Type III secretion systems and effector molecules – 2 different sy

stems may be found:

– One type is involved in promoting entry into intestinal epithelial cel ls

– The other type is involved in the ability of Salmonella to survive ins ide macrophages

 Outer membrane proteins - involved in the ability of Salmonella t

o survive inside macrophages

 Flagella – help bacteria to move through intestinal mucous  Enterotoxin - may be involved in gastroenteritis

(54)

(55)

Enteric or typhoid fever

 Enteric or typhoid fever occurs when the bacteria l_{Enteric or typhoid fever occurs when the bacteria l}

eave the intestine and multiply within cells of the r

eave the intestine and multiply within cells of the r

eticuloendothelial system.

 The bacteria then re-enter the intestine, causing ga_{The bacteria then re-enter the intestine, causing ga}

strointestinal symptoms.

 Typhoid fever has a 10-14 day incubation period aTyphoid fever has a 10-14 day incubation period a

nd may last for several weeks.

nd may last for several weeks.

 Salmonella typhi is the most common species isolat_{Salmonella typhi is the most common species isolat}

ed from this salmonellosis.

 H_Human reservoir_{uman reservoir}:carrier state common_:  C_Contaminated food_{ontaminated food}:_:water supply _{water supply}

(56)

Typhoid

•acute phase, gastroenteritis _{acute phase, gastroenteritis}

gall bladder

gall bladder

–shedding, weeks_{shedding, weeks}

Septicemia

-occurs 10-14 days

– _{lasts 7 days}_{lasts 7 days}

gastrointenteritis

(57)

鞭鞭 --- 鞭鞭 --- 鞭鞭鞭 / 鞭鞭鞭鞭鞭鞭

鞭 --- 鞭鞭鞭 --- 鞭鞭鞭鞭 --- 鞭鞭鞭

鞭鞭 ---- 鞭鞭鞭鞭 -- 鞭鞭鞭

伤伤伤伤伤伤伤伤伤伤伤

鞭鞭鞭鞭鞭鞭鞭鞭鞭

鞭鞭鞭鞭鞭鞭

鞭鞭鞭鞭鞭鞭鞭鞭鞭鞭鞭鞭

鞭鞭鞭鞭鞭鞭鞭鞭鞭鞭

(58)

Typhoid -Therapy



Antibiotics

–

essential



Vaccines

(59)

Salmonella

gastroenteritis

 Salmonella gastroenteritis is the most common _{Salmonella gastroenteritis is the most common}

form of salmonellosis and generally requires an

form of salmonellosis and generally requires an

8-48 hour incubation period and may last from

2-5 days.

 Symptoms include nausea, vomiting and diarrh_{Symptoms include nausea, vomiting and diarrh}

ea

ea ((non-bloody stoolnon-bloody stool)). Salmonella enteritidis is t. Salmonella enteritidis is t he most common isolate.

he most common isolate.

(60)

Salmonella

septicemia

 Salmonella septicemia (bacteremia) may be c

(61)

Immunity (

S. typhi

)

(62)

D

iagnosis



A. Specimens



a) Enteric fever: blood, bone marrow, st

ool, urine.



b) Food poisoning: stool, vomitus, suspe

cted food.



c) Septicemia: blood.



B. Culture and identification

(63)

(64)

Salmonella

 _{Using appropriate antibodies more than 2000 antigenic “types” have been recognized. The}

re are, however, only a few types that are commonly associated with characteristic human diseases (most simply referred to as S. enteritidis, S. cholerae-suis and S. typhi).

 _{Salmonellosis, the common salmonella infection, is caused by a variety of serotypes (S. en}

teritidis) and is transmitted from contaminated food (such as poultry and eggs). It does not have a human reservoir and usually presents as gastroenteritis (nausea, vomiting and non-bloody stools). The disease is usually self-limiting (2-5 days). Like Shigella they invade t he epithelium and do not produce systemic infection. In uncomplicated cases of salmonell osis, which are the vast majority, antibiotic therapy is not useful. S. cholerae-suis (seen m uch less commonly) causes septicemia after invasion. In this case, antibiotic therapy is req uired. .

 _{The severest form of salmonella infections "typhoid" (enteric fever), caused by}_Salmonell

(65)

Klebsiella

– _{NF of GI tract, but potential pathogen in other areas} – _{Virulence factors}

 Capsule  Adhesions

 Iron capturing ability

– _{Clinical significance}

 Causes pneumonia, mostly in immunocompromised hosts.

Permanent lung damage is a frequent occurrence (rare in o ther types of bacterial pneumonia)

 A major cause of nosocomial infections such as septicemia a

(66)

Klebsiella



K. pneumoniae (Friedlander bacilli): may c

ause primary pneumonia, urinary tract and

wound infections, bacteremia, meningitis, et

c.



K. rhinoscleromatis: pathogen of granumat

ous destruction of nose and pharynx.



K. ozaenae: causes chronic atrophic rhinitis

.

(67)

Proteus

 General characteristics: “swarming” phenomenon o_{General characteristics: “swarming” phenomenon o}

n nonselective agar

n nonselective agar (P.vulgaris; P.mirabilis and P.my(P.vulgaris; P.mirabilis and P.my xofaciens)

xofaciens)

 P.vulgaris strains (OX-19, OX-K, OX-2)have commo_{P.vulgaris strains (OX-19, OX-K, OX-2)have commo}

n antigen with Rickettsia (Weil-Felix test).