PHARMACEUTICAL MICROBIOLOGY -1I PHT 313 Dr. Rasheeda HamidAbdalla Assistant Professor E-mail rasheedahamed12@hotmail.com

Other Enterobacteriaceae

Objectives Enterobacter Citrobacter Proteus Salmonella

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

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.

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

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

Swarming Growth On Blood Agar

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

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

Antigenic Structures of Salmonellae Used in Serologic Typing

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

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

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

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

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.

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

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