1. PHARMACEUTICAL MICROBIOLOGY -1I PHT 313
Dr. Rasheeda HamidAbdalla
Assistant Professor

2. Other Enterobacteriaceae

3. Objectives
Enterobacter
Citrobacter
Proteus
Salmonella

4. Enterobacter Gram-negative, Facultative anaerobic, Rod-shaped,
Non-spore-forming bacteria of the family Enterobacteriaceae
Motile and Lac+
They are rarely cause primary disease in humans

6. Enterobacter
Frequently colonize hospitalized patients especially in associations with antibiotic treatment
Indwelling catheters
May infect burns ,wounds , the respiratory tract (causing pneumonia),or urinary tract Two clinically important species from this genus are
 E. aerogenes  and E. cloacae.

7. Citrobacter
Citrobacter  is a genus of  gram negative coliform bacteria in the Enterobacteriaceae family
Lac+
The species C. amalonaticus, C. koseri, and 
C. freundii can use citrate as a sole carbon source
Citrobacter species are differentiated by their ability to convert tryptophan to indole
Causes  UTI , infant meningitis, and sepsis

8. Proteus Species Proteus mirabilis and Proteus vulgaris
Proteus  includes pathogens responsible for urinary tract infections
Other extra-intestinal infection such as wound infections , pneumonias and septicemias , are associated with compromised patients
Proteus mirabilis and Proteus vulgaris
Isolated from urine, wounds, ear, and blood infections
Generally produce swarming on laboratory media
Burnt chocolate odor
Produce H2S
Produce urease

9. Swarming Growth On Blood Agar

10. Salmonella Gram-negative rods, facultatively anaerobic
Produce acid and gas during fermentation of glucose
Clear, colorless, non-lactose fermenting colonies with black centers
Lipopolysaccharides (both lipid A and O antigens) and Vi are virulence factors

11. Salmonella All strains are grouped in a single species, S.enterica
S.enterica divided into over 1500 serotype based on:-
The cell wall (O) antigen
Flagellar (H) antigen
Capsular (vi analogous to K) antigen
Serotypes Typhimurium and Typhi are of particular clinical significance

12. Antigenic Structures of Salmonellae Used in Serologic Typing

13. Clinical significance
Salmonella can cause both intestinal and extraintestinal diseases
1-Gastroenteritis
Local disease caused by
S.enteritidis and S.typhimurium
characterized by nausea , vomiting ,and diarrhea ( usually non-bloody),which develop generally within 48hours of ingesting contaminated food or water
Fever and abdominal cramping are common
In uncompromised patients the disease is generally self limiting (48-72 hours)
Convalescent carriage of the organisms may persist for a month or more

14. Clinical significance
2- Enteric(typhoid )Fever
It is caused primarily by S.typhi but other serotype can cause this disease
Ingestion of organism
Development of fever, malaise, anorexia, lethargy, myalgia, and a dull headache
30% of patients have a faint maculopapular rash on the trunk (rose spots
Looks like the flu
Reach the small intestine invade and penetrate the intestinal mucosa
Leads to constipation
Some time cause diarrhea
Enter the lymphatic system and are sustained in mesenteric lymph nodes

15. Typhoid Fever Disease Course (Cont’d)
Seed the bloodstream
Spread to spleen, liver, and bone marrow
Engulfed by monocytes and grow intracellularly
Rereleased into the blood stream
Prolonged bacteremia
“Rose spots” in the periumbilical region

17. Typhoid Fever Disease Course (Cont’d)
Invasion of the gallbladder and Peyer’s patches; and release of bacteria into the bowel via the biliary duct
Gallbladder is the foci in long-term infections
Severe infections can cause necrosis of gallbladder, Peyer’s patches
Hemorrhage and perforation of the bowel

18. Laboratory identification
In patients with diarrhea, Salmonella can typically be isolated from stools on MacConkey agar or moderately selective media
For patients with enteric fever, appropriate specimens include blood, bone marrow, urine, stool, and tissue from typical rose spots.

19. Treatment and prevention
For gastroenteritis in uncompromised hosts, antibiotic therapy is often not needed.
For enteric fever, appropriate antibiotics include β-lactams and fluoroquinolones
Prevention
-proper sewage disposal
- correct handling of food
- good personal hygiene

20. Thanks