Typhoid fever deepa babin

Diagnosis of

deepababin@gmail.com
Typhoid Fever
A Clinical Problem Based Learning
Deepa Babin
1

Case study
• A 20 years old male medical student presented with fever
since one week. The temperature chart shows step ladder
pattern of fever. On clinical examination patient is having
mild hepatomegaly.

• 1. What can be your provisional diagnosis?
• 2. What are the microbiological investigations for diagnosing
this condition?
• 3. What is the importance of Antibiotic sensitivity in this
condition?
• 4. How you will prevent this infection?
2

Observe the Step Ladder Pattern
of Temperature

3

Answer

• It can be case of Enteric fever
Microbiological diagnosis
• Specimens: Blood , Bone marrow ,Blood clot, Stool and

Urine can be cultured
• The best isolation rates from blood have
been seen in the first week of illness, with
faeces in the second week and with urine
the third week of illness. 4

Blood Cultures in Typhoid Fevers
• Bacteremia occurs
early in the disease
• Blood Cultures are
positive in
1st week in 90%
2nd week in 75%
3rd week in 60%
4th week and later in
25%

Isolation of the organism
Blood culture- Castaneda Biphasic medium

• Add a minimum of 10 ml of venous blood
from an adult patient to each of 50 ml of
Bile broth and Biphasic medium with
nutrient agar as slant and Brain heart

infusion broth as liquid medium
• From children at least 5 ml blood should
be inoculated in each of the bottles.
• Incubate the inoculated media at 37oC
overnight and subculture into
• MacConkey agar
6
• Blood agar

Further Incubation up to 7 days

• Incubate up to 7 days if subcultures fail to
yield any bacterial growth.
• Subculture again on day 7 and if no

growth is obtained blood culture may be
declared as negative for enteric fever
bacilli.
• Periodic subcultures are made after day 2,
5 and 7 on MacConkey agar.
7

Clot culture
• The clot culture has following advantages over
blood culture namely
• Serum is available for antibody titration.
• The clot can be put in blood culture bottles and

can be broken either mechanically or by adding
streptokinase, if available.
Urine culture
• Urine culture is positive in a quarter to one third
of cases, but there seems to be no regular
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excretion pattern in the urine

Clot culture
• Clot cultures are more
productive in yielding
better results in
isolation.

• A blood after clotting,
the clot is lysed with
Streptokinase ,but
expensive to perform in
developing countries.
9

Culture Medias
Mac Conkeys agar
Deoxycholate citrate agar (DCA)
Selenite F broth as enrichment
medium.
Cultural characters

DCA - pale yellow colonies, 2-3 mm
in diameter, moist, circular and
smooth convex surface.

MacConkeyagar-non lactose
fermenting colonies

10

Salmonella on Mac Conkey's agar

11

Salmonella on XLD agar

12

Biochemical reactions I M Vi C TSI U
_ + _ _ K/A H2s _

• Catalase positive and Oxidase
negative.
• I M Vi C _ + _ _
• TSI - K/A with H2S

• Urease Negative
• Gram smear-Gram negative
bacilli

13

Slide agglutination
• On the basis of biochemical reactions, the
organism has been identified as Salmonella; its
identity can be confirmed with slide agglutination
test, using polyvalent 'O' and polyvalent 'H'
antisera against salmonellae.

• For identification monovalent 'O' specific
antiserum for S.typhi is factor 9.
• To perform this test 1 drop each of normal saline
is placed at two different sites on a clean glass
slide.
14

Slide agglutination tests
• In slide agglutination
tests a known serum
and unknown culture
isolate is mixed,
clumping occurs within
few minutes
• Commercial sera are
available for detection
of A, B,C1,C2,D, and E.

Slide agglutination

• A loopful of biochemically suspect colony of
Salmonella is emulsified in both. One of these is
kept as central and another is tested first with
polyvalent 'O' antiserum against Salmonella.

• If this gives visible agglutination within 2
minutes, the process is repeated with
polyvalent 'H' antiserum and then with factor 9
antiserum

16

Other methods of Diagnosis of Typhoid
fever
• WIDAL TEST
• Serum agglutinins raise abruptly during the 2nd or 3rd
week.The widal test detects antibodies against O,
H,AH,BH antigens
• Two serum specimens obtained at intervals of 7 – 10

days to read the raise of antibodies.
• Serial dilutions on unknown sera are tested against the
antigens for respective Salmonella
• False positives and False negative limits the utility of the test
O > 1 in 160
H > 1 in 320
Typhidot
Detects specific IgM and IgG antibodies to S. typhi 17

. Antimicrobial susceptibility testing
• The emergence and spread of S.typhi
resistant to multiple antibiotics shows
the need for susceptibility testing.
• Multi-drug resistant typhoid fever has
become endemic in many developing
countries.

• Resistant to Chloramphenicol,
Ampicillin and Trimethoprim
sulfamethoxazole.
• Choice of drug
• Fluoroquinolones
(ciprofloxacin,Ofloxacin)
Third gen
Cephalosporins(Cefotaxime,Ceftri 18
azone,Ceftazidime)

BACTEK and Radiometric based
methods are in recent use

• BACTEK methods in
isolation of Salmonella
is a rapid and sensitive
method in early
diagnosis of Enteric
fever.
• Many Microbiology
Diagnostic Laboratories
are upgrading to
Bactek methods

Prevention

• Good Sanitary measures
• Typhoid vaccine(TAB Vaccine)
Heat inactivated phenol
preserved vaccine.

• Divalent vaccine in India
• Dosage- Two doses four weeks
apart with single booster dose
every three years
20

• Programme created for Medical and
Paramedical students for orientation on

Clinical Based Learning
• Email
• deepababin@gmail.com

21

Typhoid fever deepa babin

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