Gram Negative Bacilli

Glucose-fermenter Oxidase-negative

Enterobacteriaceae

Glucose-fermenter
Oxidase-positive

- Vibrionaceae
- Plesiomonaceae

Non-glucose fermenter

- Pseudomonas
- Burkholderia
- Flavobacteria
- Acinetobacter

Fastidious and Other GNB

- Bordetella
- Campylobacter
- Eikenella
- Gardnerella
- Haemophilus
- Pasteurella
- Brucella
- Cardiobacterium
- Kingella
- Legionella
- Helicobacter

only gram negative bacilli that is not inhabitant of large intestine

Yersinia pestis

Lactose Fermenter

- E. coli
- Klebsiella spp.
- Enterobacter spp.
- Citrobacter spp.
- Serratia spp.
- Edwardsiella spp.
- Hafnia spp.
- Shigella sonnei
- Salmonella arizonae
- Yersinia enterocolitica

Non-Lactose Fermenter

- Proteus spp.
- Providencia spp.
- Morganella spp.
- Salmonella spp.
- Shigella spp.
- Yersinia spp.
- Erwinia spp.
- Arizona spp.

H2S PRODUCERS

- Proteus spp.
- Salmonella spp.
- Citrobacter spp.
- Edwardsiella spp.
- Salmonella arizonae

significant as an indicator of disease or infection (gastrointestinal manifested by diarrhea) when isolated

1. Salmonella spp.
2. Shigella spp.
3. Yersinia spp.
4. Some strains of Escherichia coli

is Enterobacteriaceae glucose fermenter?

YES

is Enterobacteriaceae facultative aerobe?

NO

Enterobacteriaceae is Oxidase POSITIVE

NO

Enterobacteriaceae is Catalase POSITIVE

YES

is Enterobacteriaceae a non-spore former?

YES

Enterobacteriaceae is non-encapsulated

YES

Oxidase POSITIVE Enterobacteriaceae

Plesiomonas shigelloides

Catalase NEGATIVE Enterobacteriaceae

Shigella dysenteriae type 1

encapsulated Enterobacteriaceae

Klebsiella spp. and Enterobacter spp.

is Enterobacteriaceae motile or non-motile?

MOTILE

non-motile Enterobacteriaceae

Klebsiella spp. and Shigella spp.

resident flora in GIT

Enterobacteriaceae

does Enterobacteriaceae reduce NITRITE TO NITRATE?

NO

characteristics of Enterobacteriaceae in BAP

large, dull-gray colonies with variable hemolysis

Pathogenicity of Enterobacteriaceae

- Lipopolysaccharide
- Antigens
- Virulence factors

Lipopolysaccharide of Enterobacteriaceae

● Core polysaccharide
● O polysaccharide (somatic antigen)
● Lipid A (endotoxin)

Antigens of Enterobacteriaceae

● Somatic (O)

● Capsular (K)

● Flagellar (H)

● Virulence (Vi)

binding sites of specific antibody

Antigen

Antigen found in the cell wall

Somatic (O) antigen

Antigen found in the capsule

Capsular (K) antigen

Antigen found in the flagella

Flagellar (H) antigen

Antigen that is specific and exclusive only for Salmonella typhi

Virulence (Vi)

Virulence factors of Enterobacteriaceae

● Immune evasion
● Adhesins
● Endotoxins
● Hemolysins
● Iron-binding compounds
● Plasmids

Immune evasion subtypes

○ Capsule

○ Fimbriae

○ Type III secretion system

anti-phagocytic

capsule

present in flagellated bacteria except Neisseria gonorrhoeae

Fimbriae

2 types of toxins found in Gram Negative Bacilli

Exotoxin and Endotoxin

Toxin that is released from the cell before or after lysis

Exotoxin

Toxin that is an integral part of cell wall

Endotoxin

Toxin that has protein

Exotoxin

Toxin that has lipopolysaccharide

Endotoxin

Toxin that is heat labile

Exotoxin

Toxin that is heat stable

Endotoxin

Toxin that is antigenic and Immunogenic

Exotoxin and Endotoxin

Toxoids can be produced

Exotoxin

Toxoids CANNOT be produced

Endotoxin

ability to stimulate production
of antibody

immunogenic

produced by B cells (B
lymphocyte)

antibody

Toxin that has specific effect on host

Exotoxin

Toxin that has MANY effect on host

Endotoxin

Toxins that are produced by gram-positive and gram negative organisms

Exotoxin

Toxin that are produced by gram-negative organisms only

Endotoxin

component of somatic (O) antigen

Lipopolysaccharide

component of capsular (K) antigen

polysaccharide

component of flagellar (H) antigen

protein

component of virulence (Vi) antigen

polysaccharide

characteristics of somatic (O) antigen

heat stable

characteristics of capsular (K) antigen

heat labile

characteristics of flagellar (H) antigen

heat labile

characteristics of virulence (Vi) antigen

heat labile

may be described as Typhoid fever, Paratyphoid fever, or Non-typhoid fever

Salmonellosis

S. typhi disease

typhoid fever

S. parathypi A disease

paratyphoid fever, with or without
gastroenteritis / diarrhea

S. enteritidis or typhymurium disease

food poisoning / acute gastroenteritis

S. cholerasuis disease

non-typhoidal fever without or with gastroenteritis / diarrhea

Enterobacteriaceae is generally referred to as

"Enterics"

Enterobacteriaceae are considered as pathogens and non-glucose fermenters

pathogens and GLUCOSE FERMENTERS

Enterobacteriaceae is considered as endogenous and exogenous

YES

Enterobacteriaceae mode of transition

- ingestion
- inhalation
- nosocomial
- iatrogenic infection
- direct skin penetration

nosocomial means

hospital acquired

iatrogenic infection means

transmitted via medical procedure

"Enterics" majority exist in what organ of humans and animals

large intestine

SYMPTOMS of Typhoid fever / Enteric fever

Severe frontal headache
Anorexia
Malaise
Myalgia

SYMPTOMS of Acute Gastroenteritis

Fever
Abdominal pain
Watery diarrhea
Nausea
Chills
Vomiting

SYMPTOMS of Bacteremia

prolonged fever

site of long-term carriage of Typhoid Fever/Enteric Fever

gallbladder

occurs with or without extraintestinal infection caused by
non-typhoidal species

Bacteremia

does Shigella species on culture media have almost the same
morphological characteristics and same requirements to grow?

YES

usually used for Shigella typing

somatic antibody

Shigella species resides in

large intestines

What is the cause if the bacteria you are testing is negative to all serotypes?

It has a capsule

How can you correct if the bacteria you are testing is negative to all serotypes?

put NSS or distilled water in a sterile test tube -> put
a colony of bacteria → put in a beaker with water → put on a hot plate

required temperature to destroy the capsule of Shigella

50-60°C

serological type of S. dysenteriae

serotype A

serological type of S. flexneri

serotype B

serological type of S. boydii

serotype C

serological type of S. sonnei

serotype D

other name of S. dysenteriae

Shiga's bacillus

other name of S. flexneri

Strong's bacillus

other name of S. boydii

new castle manchester bacillus

other name of S. sonnei

Duval's bacillus

bacillary dysentery or shigellosis is characterized by

acute inflammatory colitis and bloody diarrhea

agent of bacillary dysentery

Shigella

agent of amoebic dysentery

Amoeba (Entamoeba histolytica)

Fecalysis: many RBC

bacillary dysentery

Fecalysis: Many WBC but no RBC

amoebic dysentery

symptoms of bacillary dysentery after several hours

Fever
Abdominal cramps
Tenesmus
Chills
Painful bowel movement

Feeling of defecating but there is nothing coming out

tenesmus

2 significant Yersinia spp.

Yersinia pestis and Yersinia enterocolitica

transmitted via ingestion causing gastroenteritis

Yersinia enterocolitica

causes plague via flea

Yersinia pestis