1. 10Q review—enterobacteriaceae I

2. Lactose fermenters are what color on MacConkey agar
Colorless
Pink
Purple
Blue

3. E. coli are Gram positive, oxidase positive
Gram positive, oxidase negative
Gram negative, oxidase positive
Gram negative, oxidase negative

4. An endotoxin carried by Enterobacteriaceae is called
Polysaccharide
O-antigen
LPS
Capsule

5. E. coli are abundant normal flora in/on the
Gastrointestinal tract
Respiratory tract
Skin
Urinary tract

6. E. coli (with specific virulence factors) are associated with what kind of infection?
Conjunctivitis
Line associated bacteremia
Gastroenteritis
Endocarditis

7. Shiga-toxin carrying strains of E. coli can cause
Hemolytic uremic syndrome
Rheumatic fever
Glomerulonephritis
Respiratory tract infection

8. Treatment of STEC diarrhea with antibiotics is recommended?
Yes No

9. Clinical symptoms associated with ETEC are caused by
Invasion of the gastrointestinal epithelium
A super antigen toxin
A hyaluronidase
Heat-labile and heat-stabile toxins

10. EIEC is similar to which other bacteria
Salmonella
Shigella
Yersinia
Citrobacter

11. A common serotype of E. coli that is associated with food-borne illness is
OEIEIO

12. 10Q review—enterobacteriaceae II

13. Shigella are Lactose fermenters and H2S producers
Non-lactose fermenters and H2S producers
Lactose fermenters and do not produce H2S
Non-lactose fermenters and do not produce H2S

14. Only E. coli carry Shiga toxin
Yes No

15. Non-typhoid strains of Salmonella are normal flora for all but
Humans
Reptiles
Cows
Poultry

16. Typhoid strains are normal flora for
Humans
Reptiles
Cows
Poultry

17. A hallmark of Salmonella typhi infection is
Black eschar
Strawberry tongue
Rose spots
Purple halo

18. Klebsiella pneumonia can cause lobar pneumonia with sputum characterized as
Yellow goop
Currant jelly
Black tar
Grape jelly

19. Proteus produces an enzyme that promotes infection in the urinary tract
Oxidase
Catalase
Urease
Coagulase

20. A major reservoir for Yersinia enterocolitica is
Humans
Pigs
Cows
Poultry

21. Infection with Yersinia enterocolitica can mimic
Appendicitis
Kidney stones
Endocarditis
Hepatitis

22. EMB agar helps differentiate
Sucrose fermenters
Lactose fermenters
Shiga toxin producers
Oxidase positive organisms

23. Pseudomonas aeruginosa and Other Non-Fermenting Bacilli
SSOM-MHD
Pseudomonas aeruginosa and Other Non-Fermenting Bacilli
Amanda T. Harrington, PhD, D(ABMM)
Associate Professor, Pathology and Laboratory Medicine
Director, Clinical Microbiology Laboratory
@aharrington1884

24. Pseudomonas aeruginosa and Other Non-Fermenting Bacilli
Reading Assignment: Murray et al., Medical Microbiology, 8th ed., Chapter 27

25. Pseudomonas aeruginosa and Other Non-Fermenting Bacilli
OBJECTIVES
Describe the type of patients who acquire Pseudomonas aeruginosa infections
List major toxins produced by Pseudomonas aeruginosa and describe their principle effect on human cells.
Discuss the association of Burkholderia cepacia complex and pulmonary infection in cystic fibrosis patients
Describe the gene defect and resultant pathology of cystic fibrosis disease

26. Pseudomonas aeruginosa and Other Non-Fermenting Bacilli
OBJECTIVES
List diseases associated with Stenotrophomonas maltophilia, Burkholderia cepacia complex, Burkholderia pseudomallei, Acinetobacter baumannii
Name Non-Fermenting bacteria that are listed as potential bioterrorist agents

27. Some kid in PE told a shocker: Bacteria lived in his locker!
(What bio-class beaker's
As rich as old sneakers
And socks full of microbes from soccer?)
Poem by A. M. Warren on OEDILF

29. Glucose Non-Fermenting Gram-Negative Bacilli
Gram‑negative, nonsporeforming bacteria, may be rods, or coccobacilli
Obligate aerobes
Good growth usually seen in 24 h
Glucose not fermented
Natural Habitat: water, soil, plants

31. The Oxidase Test
Identify bacteria that produce cytochrome c oxidase, an enzyme of the bacterial electron transport chain.  
Cytochrome c oxidase oxidizes the reagent (tetramethyl-p-phenylenediamine) to (indophenols) purple color end product.

32. Pseudomonas aeruginosa Key Characteristics
Beta-hemolytic colonies
Gram negative rods
Oxidase +

33. Pseudomonas aeruginosa
Aerobic Gram negative rod
Motile with polar flagella
Mucoid polysaccharide slime layer
Pili on cell surface
Mucoid strains common is CF patients

34. Pseudomonas aeruginosa Epidemiology
Environmental organism
Grows in unsterile water, medications, disinfectants
Hospital environment
Moist areas
Sinks
Toilets
Cut flowers
Floor mops
Equipment

35. Pseudomonas aeruginosa Infection
Factors Predisposing to serious infection
Burn patients
Cystic fibrosis patients
Patients with hematologic malignancies
Immunocompromised patients
Can be part of the microbial flora in hospitalized patients and ambulatory, immunocompromised hosts
Infections occur at any site where moisture tends to accumulate, indwelling catheres, trach sites, burns, external ear

36. Pseudomonas aeruginosa Infection
Skin Infection
Burn wounds
Folliculitis
Hot tubs, whirlpools, swimming pools, water slides
Nail infections

37. Pseudomonas aeruginosa Infection
Pulmonary Infection
Asymptomatic colonization
Cystic fibrosis, chronic lung disease
Severe necrotizing bronchopneumonia
Most common cause of ventilator associated pneumonia (VAP)

38. Pseudomonas aeruginosa Infection
Urinary tract infections
Ear infections
“Swimmers ear”
Malignant external otitis
Chronic otitis media
Eye Infections
Contact lenses
Trauma
Bacteremia
Ecthyma gangrenosum
Sepsis
Endocarditis
IVDA and involves the tricuspid valve
Osteomyelitis

39. Pseudomonas aeruginosa Infection
Bacteremia with ecthyma gangrenosum
EG is a well-recognized but uncommon cutaneous infection most often associated with a Pseudomonas aeruginosa bacteremia.
EG usually occurs in patients who are critically ill and immunocompromised and is almost always a sign of pseudomonal sepsis.

40. Pseudomonas aeruginosa Infection
Ecthyma gangrenosum
Characteristic lesions are hemorrhagic pustules or infarcted-appearing areas with surrounding erythema that evolve into necrotic ulcers surrounded by erythema.
The transformation of an early lesion to a necrotic ulcer may occur in as little as 12 h

41. PSEUDOMONAS P—Pnuemonia S—Sepsis E—Ecthyma gangremosum U—UTI
D—Diabetes
O—Osteomyelitis
M—Mucoid polysaccahride capsule
O—Otitis externa
N—Nosocomial infection
A—Addiction (IVDU)
S—Skin infection

42. Pseudomonas aeruginosa Virulence Factors
Structural
Capsule, Pili, LPS and pyocyanin
Toxins and Enzymes
Exotoxin A
Exoenzyme S
Elastase
Phospholipase C

43. Pseudomonas aeruginosa Virulence Factors
Exotoxin A
Correlates with virulence
Blocks protein synthesis much like diphtheria toxin
Most likely contributes to dermatonecrosis in wounds and tissue damage in lungs
Exoenzyme S/Phospholipase C
Epithelial cell damage facilitates bacterial spread, tissue invasion and necrosis

44. Pseudomonas aeruginosa Virulence Factors
Elastase
Results in tissue destruction and hemorrhagic lesions (ecthyma gangrenosum)
Two enzymes: Las A and Las B act synergistically to degrade elastin
Degrades compliment components and inhibits neutrophil chemotaxis and function
Deegrading elastin leads to damage to elastin containing tissues and producing the lung parenchymal damage and hemorrhagic lesions (ecthyma gangrenosum) associated with P. aeruginosa infections.

45. Pseudomonas aeruginosa Lab Identification
Culture
Grows on blood producing spready colonies with a metallic sheen
Non-lactose fermenter on MacConkey agar
Identification
Glucose Non-Fermenter
Oxidase positive
Beta hemolytic
Grape-like odor
Produces Pyocyanin-blue water soluble pigment (next slide)
Grows at 42oC
P. aeruginosa on blood agar
Original Photo: P. Schreckenberger

46. Pseudomonas aeruginosa Lab Identification
Left: P. aeruginosa with blue-green pigmentation
Right: Mucoid form of P. aeruginosa on MacConkey Agar

47. Pseudomonas aeruginosa Treatment
Resistant to many of the common antibiotics used for Gram negative infections
Often not predictable
Resistance due to several different mechanisms
Combination therapy

48. Burkholderia species Burkholderia mallei Burkholderia pseudomallei
Burkholderia cepacia complex

49. Burkholderia pseudomallei
Originally named Pseudomonas
Changed to Burkholderia in 1992
B. mallei and B. pseudomallei belong to a single genomospecies

50. Burkholderia pseudomallei Epidemiology
Habitat: soil, water, vegetation of S.E. Asia, 20o north and south of equator.
Primarily found in India, Thailand, Vietnam, northern Australia. Also endemic in China, Taiwan, Laos
Disease: Melioidosis
Category B biothreat agent

51. Burkholderia pseudomallei Infection
Melioidosis
Acute Disease: septicemia with metastatic lesions. 95% mortality if untreated
Subacute Disease: most common. TB like pneumonia with cellulitis and lymphangitis
Chronic Disease: localized chronic cellulitis. Treat with antibiotics before draining otherwise become bacteremic

52. Burkholderia cepacia complex
Formerly a Pseudomonas
18 species
Recovered from water sources, wet surfaces, detergent solutions
60% isolated from respiratory tract infections.
Major clinical problem in patients with cystic fibrosis (CF) and chronic granulomatous disease (CGD)
Urinary tract infections
Septicemia
Other opportunistic infections

53. Overview of Cystic Fibrosis
Most common autosomal recessive genetic disease in Caucasians
Caused by a mutation in gene: cystic fibrosis transmembrane conductance regulator (CFTR)
Regulates components of sweat, digestive juices, mucus.
Persons without CF have two working copies of CFTR gene, only one is needed to prevent CF.
CF develops when neither allele can produce a functional CFTR protein and therefore has autosomal inheritance.
Approx. 1:25 persons of European descent, and 1:30 Caucasian Americans, carry CFTR gene mutation.

54. Overview of Cystic Fibrosis
Mutation in CFTR results in defects in innate immunity including
decreased nitric oxide levels
failure to internalize bacteria in bronchial epithelial cells
increased inflammation in CF airway
abnormal electrolyte transport causing thick, dry, sticky mucus
Abnormal mucus adversely effects mucocilliary clearance providing ideal niche for chronic lung infection

55. Overview of Cystic Fibrosis
Over 85% of premature deaths in CF are due to cardiopulmonary failure secondary to chronic lung infection
In US median life expectancy is 37 yrs.
Lung transplant is often necessary as CF worsens
CF may be diagnosed by many different methods including newborn screening, sweat testing, and genetic testing.

56. Burkholderia cepacia complex Lab Identification
Resistant to most antibiotics
Glucose non-fermenter
May be yellow pigmented
Slow oxidase-positive
Original Photo: Paul C. Schreckenberger

57. Stenotrophomonas maltophilia
First called Pseudomonas then Xanthomonas and now Stenotrophomonas
Opportunistic infection
Bacteremia
Pneumonia
Meningitis
Wound infections
Urinary tract

58. Stenotrophomonas maltophilia Epidemiology
Habitat:
Worldwide distribution
Soil, water, animals, vegetation, crops
Not part of normal skin or gastrointestinal flora but can be recovered from almost any clinical site
Respiratory tract most common (>60%)

59. Stenotrophomonas maltophilia Infection
>95% of all clinical infections are hospital acquired
2nd leading cause of Gram-negative non-fermentative bacillary infections
Hallmark of S. maltophilia disease is life-threatening systemic infections in debilitated patients (usually malignancy)

60. Stenotrophomonas maltophilia Lab Identification
Good growth on blood agar and MacConkey
Oxidase negative
Some strains have yellow pigment
Original Photo: Paul C. Schreckenberger

61. Stenotrophomonas maltophilia Treatment
Multi-drug resistant organism
Intrinsically resistant to carbapenems

62. Acinetobacter baumanii Key Characteristics
Non-lactose fermenter
Gram negative coccobacilli
Oxidase -

63. Acinetobacter baumanii Epidemiology
Habitat
Free living in water and soil
Isolated foods, hospital air, inanimate objects, numerous human sources
Common gram-negative organism carried on skin of hospital personnel
Found on hospital equipment

64. Acinetobacter baumanii Infection
Low virulence
Implicated in community acquired and nosocomial infections
Recovered from numerous human sources: blood, sputum, urine, feces, vagina
Found to colonize 45% of inpatient tracheostomy
Often multi-drug resistant

65. Acinetobacter baumanii Lab Identification
Gram negative coccobacilli on Gram stain
May be initially reported as Gram positive
Good growth on blood agar and MacConkey
Oxidase negative
Non-motile