2. By Prof. Dr. Asem Shehabi and Dr. Suzan Matar
Enteric Bacteria By
Prof. Dr. Asem Shehabi and Dr. Suzan Matar

3. Enterobacteriaceae
E.coli
Klebsiella-Enterobacter species
Proteus-Providencia species
Salmonella and Shigella
Pseudomonas aeruginosa
Vibrio cholerae
Campylobacter
Helicobacter
Brucella

4. Enteric Bacteria (Escherichia, Klebsiella, Enterobacter, Proteus, Salmonella, Shigella, Yersinia )
General Characteristics:
Gram - ve bacilli,
Facultative anaerobes,
Intestinal normal flora..
Humans, animals, birds..
Common waste water, natural water, soil, vegetation
Lactose fermenters and Lactose non fermenters
Catalase +ve & Oxidase –ve
Opportunistic Pathogens & Obligate Pathogens
- Causing all types of human infection, some common nosocomial infections.
All ferment glucose
Lactose fermenting genera are generally benign; non lactose fermenting genera are more pathogenic.
Human pathogens: Salmonella , Shigella, Yersinia are invasive . Disease acquired from animal reservoirs or human carriers.
Opportunistic organisms : E.coli, Klebsiella, Enterobacter and Proteus are noninvasive, part of normal flora. Disease occurs when organisms are introduced into normally sterile sites. Immunocompromised and debilitated patients are at greatest risk …some acquire specific virulence factors.
Nosocomial infections: by Enterobacter and Klebsiella

5. O-H-K-Antigens. Develop specific antibodies following blood infections
Pathogenicity:
Various Enterotoxins,
Endotoxins
Capsule,
Flagella,
O-H-K-Antigens. Develop specific antibodies following blood infections
Coliform Group:
1. Escherichia coli:
Common Urinary Tract Infection (40-80%)
Single organism, Septicemia, Neonatal Meningitis, Wounds.
Endotoxin mediated toxicity with septicemia …
Fever, Leukopenia followed by leukocytosis
Thrombocytopenia, DIC, decresaed peripheral circulation and perfusin to major organs, shock and death
E. Coli primary cause of UTI
E. Coli and group B streptococci are the most common causes of neonatal meningitis

6. Diarrheagenic E. coli Types
6 major types causing diarrhea: Common types.
1- Enteropathogenic (EPEC)
Numerous strains (mostly infants 1-6 months),Watery diarrhea, less Vomiting, Chronic cases/ fatal.
2-Enterotoxigenic (ETEC)
(Heat-labile/stable enterotoxins)/ watery diarrhea, Children more than adults, Traveler’s diarrhea, fecal water contamination /vegetables / fresh food, Indicator standard of hygiene,
Self-limited diarrhea and no antibiotics treatment.
3 Enterohaemorrhagic (EHEC):O157:H7, Verotoxins, Common in intestinal Cattle, Contamination Ground meat/Hamburger, Dairy products, bloody diarrhea, Haemolytic-uremic syndrome (HUS), fatal
Diarrheagenic E. coli Types
Diarrheagenic= Gastroenteritis
EPEC= Adherence and destruction of epithelial cells (small intestine)
ETEC= Enterotoxins (small intestine)

7. E. coli Culture – Red color on MacConkey agar indicates Lactose positive & Gram-stain

8. Coli-form Bacteria 2. Klebsiella - Enterobacter species :
UTI, Septicemia, Wounds.. Rare Meningitis.. Common Hospitalized patients..
Encapsulated K. pneumoniae cause Nosocomial infections and Pneumonia
3. Proteus-Providencia species:
UTI, Septicemia, Wounds, Nosocomial infection.
Proteus causes renal stones. Urease positive .
Encapsulated K. pneumoniae= antiphagositic properties
Pneumonia in alcoholics and individulas with compromised pulmonary function.
Pseudomonas : enzymes prevent phagocytosis, damage host tissues and antibiotic resistance.
Fruity odor
External otitis media= swimmer’s ear
Moist reservoirs: respiratory and dialysis equipments, cut flowers, sinks , bars of soap.
Exotoxin A= inhibit protein synthesis

9. 3. Pseudomonas group
Pseudomonas species , Gram-ve bacilli , Facultative anaerobe, oxidase+ve and Lactose-ve.. Found in soil, water, plants , animals. . Survive under harsh condition, including Alcohol used in aseptic procedure. More than 20 pseudomonal species can cause human infections.
P. aeruginosa :opportunistic pathogen.. colonize URT & intestine humans.. Produce blue-green pigmention / pyocyanin and fluorescein..release many enzymes. It is the most common species causes a clinically significant infection.. often causing nosocomial infections..serious and often life-threatening diseases..wound, blood sepsis, pneumonia, External ear infection..burn cases, Urinary catheters, intravenous [IV] line, endotracheal tubes. P. aeruginosa .. innate resistance to many antibiotics.. Develop rapidly resistance to antimicrobial agents.

10. E. coli- Flagella- Fimbriae - Pili Klebsiella pneumonia-Capsule

11. Salmonella group Gram-ve bacilli.. Facultative anaerobes
Lactose-non fermenters
Endotoxin / LPS.
Common in Nature (water and soil), Humans, Animals, Birds. They are not part of the normal human flora.
O/H Antigens with specific antibodies.
Pathogenic when ingested causing enteritis, systemic infections and enteric fever.
1. Nontyphoidal Salmonellosis / Gastroenteritis /Food-poisoning S. enterica/enteritidis Serotypes..
Numerous serotypes are recognized based on surface antigens.

12. - Food borne disease , Incubation 8-24 h..
Zoonotic .. Common Birds, Farm Chickens, Pets, Reptiles.. Contamination fresh food, Chicken, Meat-Eggs, Dairy products.. Large number of Salmonella cells causing diarrhea
- Food borne disease , Incubation h..
Mild-severe watery-bloody diarrhea, Vomiting, Fever
Self-Limiting in healthy persons
Rarely Septicemia - Meningitis Infant / young Children.. Immunocompromised patients.
Human healthy carriers.. Short periods..animals long period crriers
Lab Diagnosis
Culture Feces or Food.. Prevention and Control , Sanitation & hygiene in restaurants & slaughter houses and food-handlers
High risk patients could be offered antibiotics fpr short time ….

13. Salmonella/ Flagella

14. Hektoen–Enteric agar: Salmonella transparent colonies, +H2s Lactose-ve
Hektoen–Enteric agar: Salmonella transparent colonies, +H2s Lactose-ve. Shigella : transparent,lactose-ve E. coli : orange colonies, Lactose-ve
Shigella = green
Salmonella transparent with black dots except S. typhi .

15. SS agar for Salmonella & Shigella Salmonella. Transparent colonies+H2s
SS agar for Salmonella & Shigella Salmonella..Transparent colonies+H2s.. Ohers fecal flora will be inhibited to 98%

16. Typhoidal Salmonella 2- Typhoidal Salmonella: (Human Enteric Fever)
Salmonella enterica /typhi & paratyphi A, B, C
Few cells Invasive, Only infect human, Fecal-Oral
Water , Food.. Incubation:1-3 Weeks
High continuous fever, Bloody Diarrhea and constipation, Septicemia, Meningitis, osteomyelitis, Hepatosplenomegaly, Intestinal perforation.
Healthy Carriers: Gallbladder, Intestine, Short period or Life Long .
- Human Healthy Carriers ..mostly women, Gallbladder (1-3%)
Lab Diagnosis: Culture Feces, blood, Urine, CSF, Bone marrow, Selective Media: S-S Agar, Hektoen-enteric.
Serological Widal Test for detection of specific antibodies against O & H antigens (Titer > 160)
Antibiotics, Human vaccine is available..
Typhoid fever
Constipation then bloody diarrhea
Contamination of food or water by salmonellae shed from carriers can spread disease (typhoid Mary)
Widal test: tube dilution agglutination test
Cholecystectomy for carrier with antibiotic treatment
O titer = acute
H titer = past infection
Sickle cell anemia are more susceptible to Salmonella
Two injections of acetone-killed bacterial suspensions of Salmonella Typhi, followed by a booster injection some months later, give partial resistance to small infectious
inocula of typhoid bacilli but not to large ones. Oral administration of a live avirulent mutant strain of Salmonella Typhi has given significant protection in areas of high endemicity. Vaccines against other salmonellae give less protection and are not recommended.

17. Shigella group Pathogenicity:
Common serotypes: S. Sonnei, S.boydii, S. dysenteriae
- Gram -ve, Lactose-ve , Susceptible to dryness, acid, Low-High Temperature
- Fecal-Oral infection. Water, fresh Vegetations,
- Few serotypes.. Infect only humans. Incubation 1-2 Days
Pathogenicity:
Endo/Enterotoxins released intestine.. Purulent-Bloody-Diarrhea.. (bacillary dysentery) with abdominal pain, fever, not invasive. No chronic or healthy carriers
S. dysenteriae (Shiga type toxins)
- Enterotoxin /Neurocytotoxin, Severe intestinal Necrosis, Fever, Severe Purulent-Bloody-Diarrhea, Abdominal Cramps, CNS Rare Septicemia.. Can be fatal without treatment.
Lab Diagnosis:
Rapid culture Feces/rectal swabs on S-S Agar, Hektoen –Enteric Agar.. Recommended Antimicrobials Treatment.. Control Sanitation & hygiene food .. Foodhandlers
Shigellae are transmitted by “food, fingers, feces, and flies” from person to person.
Invades Mucosa cells
S. Sonnei, S.boydii= mild infections
S. Dysenteriae = severe infections= shiga type I= heat labile exotoxin = affects gut and central nervous system.

18. Vibrio cholerae Gram-ve Vibrios ’comma shaped’ , motile.
Lactose-ve, oxidase positive,
Aerobic Growth and alkaline medium (pH >8-9)..
Water.. Fresh Food.. Reservoir contaminated water. Salt tolerant.
Endemic In India/Bangladish but epidemic Disease, causing human Outbreaks.. Asymptomatic/symptomatic person
V. cholerae-01: Type El-Tor..
Only Human, Fecal-oral infection.. Raw Sea/ Fresh Foods,
Small Intestine Infect.
Cholera toxin- enterotoxin, Incubation 8-48 h, Heat labile toxin
Severe water diarrhea (rice water stool), Severe dehydration, Blood acidosis, Shock, Death within hours. No invasion.
Lab Diagnosis: Feces Culture.. Selective TCBS agar.
Treatment: Rapid replacement fluids & electrolytes.. Antibiotic Public Heath sanitation measurements. Human Vaccine.
Cholera toxin- cAMP.
Human vaccine not very effective ..short term protection.
Public Heath sanitation measurements= decontaminate water .
Has over 150 identified serotypes based on O-antigen Only O1 and O139 are toxigenic and cause Cholera disease

19. Cholera

20. TCBS agar for isolation of V. cholerae
Thiosulfate-citrate-bile salts-sucrose agar

21. Brucellosis/Malta Fever
Brucella species
Brucellosis/Malta Fever
Gram-ve coccobacilli, Microaerophilic.. Endotoxins ..Highly infectious
Primarily pathogens of animals (Zoonosis), Localized Infection in animal reproductive Organs, Sepsis ..Abortions.
B. abortus (Cattle), B. melitensis (Goats/Sheep).
- Rare other species in Jordan & Arab countries.
Transmitted to Humans:
The bacteria are transmitted from animals to humans by ingestion infected food products (Dairy ), direct contact with an infected animal, inhalation of aerosols. 
Pathogenicity:
Enter through GI, skin abrasions, eye, inhalation/Droplets
Intracellular (macrophages), Incubation:1-6 Weeks.. Intermittent fever, headaches, fatigue, joint and bone pain, GI Symptoms, Sweats, septicemia, meningitis, chronic disease with complication on CNS
Lab Diagnosis: Blood, CSF, Bone marrow cultures, Brucella weeks culture incubation. agglutination Test. Specific Antibodies (IgM and IgG)..Treatment: 6-8 Weeks with Antimicrobial drugs
The disease is an old one that has been known by various names, including Mediterranean fever, Malta fever, gastric remittent fever, and undulant fever
Brucella melitensis (from sheep; highest pathogenicity)
Brucella suis (from pigs; high pathogenicity)
Brucella abortus (from cattle; moderate pathogenicity)
Brucella canis (from dogs; moderate pathogenicity)

22. Campylobacter Species
Many species.. Most human infection C. jejuni, C. infantis
Microaerophilic.. Optimal Growth 42 C , Gram-negative thin- curved, Motile Bacilli/Bipolar flagella , Grow slowly over 3-6 days in vitro culture…This bacterium became important enteric pathogen since Widely spread in small animals, dogs, cats, birds It is primarily an animal pathogen causing abortion and enteritis in sheep and cattle.
- Human illness usually occurs 2-5 days after ingestion of the contaminated Chicken meat, Milk, fresh food , water.
- Multiply in the small intestine  invade the epithelium  produce mild inflammation  cause bloody-watery/ mild-moderate.. Few fecal leukocytes in feces..causes occasionally blood sepsis in children
Other symptoms often present are fever, abdominal pain, nausea, headache and muscle pain.. Infection may be associated with arthritis
Diagnosis: Stool culture .. Selective Campylobacter Media including 3 antibiotics/ biochemical tests.. Or direct detection of bacteria by PCR.
Lack of gastric acids and hypogammaglobulinemia increase risk of C. jejuni

23. Flagella of Helicobacter pylori & Campylobacter jejuni , Modified G-stain

24. Helicobacter Species H.pylori Helicobacter pylori
Spiral shaped bacterium with multiple flagella.
Lives in the mucus lining stomach & duodenum causes chronic inflammation..Gastritis/Ulcers
Only pathogenic in human
Release urease, converted urea into CO2/bicarbonate & ammonia neutralize stomach acidity and protects colonizing .
H.pylori
Found worldwide, up to 10% of children - 80% of adults can have evidence of an H. pylori colonization/ mild infection - usually without having any clinical signs or symptoms..
Transmission route..
- Close personal contact.
Former name - Campylobacter pylori
Diseases: Stomach and duodenal ulcers. Chronic gastritis  gastric adenocarcinoma.

25. Helicobacter Species-2
Common symptoms:
Gastritis /Peptic ulcer..Painful sores or ulcers in Stomach or duodenum...Duodenal ulcers , Nausea, Vomiting.
Persistence of ulcers  increased risk of stomach cancer and Lymphoma.
H. pylori can be successfully eradicated (95%) using a combination of certain antibiotics and medicines that suppress stomach acid production. Common Re-occurrence within few weeks - months. No vaccine
Diagnosis:
- Urea Breath test, Culture biopsy stomach .. Selective Medium with 3 antibiotics.. Incubation 37C, 4-6 days.
- Serological test: H. pylori antibodies not significant for clinical diagnosis alone.
-abdominal pain
-nausea
-flatulence
-bad breath

26. Acinetobacter group A. baumannii :
Many species.. Pleomorphic aerobic gram-negative bacillus, aerobic
Catalase +, Oxidase-ve, lactose-ve.. Commonly found in water, moist hospital environment ..contaminate irrigating solutions and intravenous solutions and respiratory equipments, catheters
Asymptomatic skin carriage, nasopharyngeal carriage
Commensal, low virulence .. Opportunistic pathogen
A. baumannii :
Common species, often represent colonization rather than infection
Found in skin, urine, wound & sputum hospitalized patients.
Nosocomial infections: in Immunodeficient patients & others ICUs-Patients . Infections: Pneumonia, Bloodstream Wound, Meningitis .. Develop rapidly resistance to most used antibiotics .. Multidrug-resistant  A baumannii  is a new emerging pathogen in hospitals worldwide with high mortality.
Acinetobacter= means non motile
Resist dryness
The organism can survive for months on clothing and bedclothes, bed rails, ventilators and other surfaces in the environment, including sinks and doorknobs, making Nosocomial transmission extremely difficult to control.
Acinetobacter commonly colonizes patients in the intensive care setting. Acinetobacter colonization is particularly common in patients who are intubated and in those who have multiple intravenous lines or monitoring devices, surgical drains, or indwelling urinary catheters..