1. Pseudomonas
Acinetobacter
Dr Kamran Afzal
Asst Prof Microbiology

2. 30 years old female
Accidentally got burnt in her house
Treated with wound dressings
I/V Vancomycin + Ceftriaxone

3. Gram stain from wound pus

5. Pseudomonas aeruginosa

6. Characteristics
 Gram negative rod
 NLF
 Oxidase and Catalase +
 Motile
 Obligate aerobe
 Non-fermentative
 Non-Enterobacteriaceae
 Optimum growth
 37˚C, can grow at 42˚C
 Minimal nutritional
requirements

7.  Two forms
 Planktonic and Biofilm
 Some strains produce
diffusible pigments
 Pyocyanin (blue/green)
 Fluorescein (yellow)
 Pyorubin (red)
 Grape-like odor
 Blue-green pus and colonies
 Broad antibiotic resistance

8. Colony types
Three types of colonies
Small rough Large smooth
colonies colonies
Mucoid
colonies

9. Transmission in hospital
 Ubiquitous to soil,  Respiratory and other
water, and vegetation hospital equipment
 Introduced in hospitals  Contaminates soaps,
on the soles of shoes,
ointments, eye drops,
on ornamental plants
and flowers disinfectants
 Persist in dampness or  Resistant to weak
standing water antiseptics and many
 Sinks, taps and mops commonly used antibiotics

10. Virulence factors

11. Pathogenicity
 Endocarditis
 Respiratory infections
 Bacteremia and Septicemia
 C N S infections
 Ear infections- otitis externa
 Eye infections
 Bone and joint infections
 Urinary tract infections
 Gastrointestinal infections
 Skin and soft tissue
infections- wound infections,
pyoderma and dermatitis

12. Bacterial Endocarditis
 IV drug users
 Prosthetic heart valves
 Bacteremia

13. Respiratory Infections
 Pneumonia
 Bacteremic pneumonia commonly occurs in
neutropenic cancer and CCF patients
 Cystic fibrosis
 Lower resp tract colonization of cystic fibrosis patients
by mucoid strains of Pseudomonas aeruginosa
Characteristics
 Production of very viscid bronchial secretions
 Tends to lead to stasis in the lungs
 Predisposes to infection

14. Bacteremia and Septicemia
 Primarily in immunocompromised patients
 Predisposing conditions
 Hematologic malignancies
 Immunodeficiency relating to AIDS
 Neutropenia
 Diabetes mellitus
 Severe burns
 Ecthyma gangrenosum

15. CNS Infections
 Meningitis
 Brain abscess
 Portal of Entry
 Inner ear or paranasal sinus
 Inoculated directly
 Surgery
 Invasive diagnostic procedures
 May spread from another
site of infection like the
urinary tract

16. Ear infections
 Otitis externa
 "swimmer's ear"

17. Eye infections
 Bacterial keratitis
 Neonatal ophthalmia
 Contaminated contact
lenses

18. Bone and Joint Infections
 Particular tropism for fibro-cartilagenous joints
of the axial skeleton
 Direct inoculation of the bacteria
 Hematogenous spread
 Osteo-chondritis
 Puncture wounds of the foot

19. Urinary Tract Infections
 Usually hospital-acquired
 UT catheterization, instrumentation or surgery
 3rd leading cause of hospital-acquired UTIs
 Most adherent to the bladder uroepithelium
 Pseudomonas can invade the bloodstream from
the urinary tract
 Source of nearly 40 % of Pseudomonas bacteremias

20. Gastrointestinal infections
 The GI tract is also an important portal of entry
in Pseudomonas septicemia
 Any part of the gastrointestinal tract
 Perirectal infections
 Pediatric diarrhea
 Gastroenteritis
 Necrotizing enterocolitis

21. Skin and Soft tissue infections
 Wound infections, pyoderma and dermatitis
 Localized and diffuse skin infections
 ‘Jaccuzzi rash’ or ‘Whirlpool rash’
 Common predisposing factors
 Breakdown of the integument
 Burns, trauma or dermatitis
 AIDS and other IC states

22. Treatment
 Pseudomonas aeruginosa is frequently resistant
to many commonly used antibiotics
 Many strains are susceptible to
 3rd and 4th gen Cephalosporins, aminoglycosides,
fluoroquinolones, carbapenems and colistin, but
resistant forms have developed
 Aminoglycoside + ceftazidime is frequently used
to treat severe Pseudomonas infections
 4th gen Cephalosporin or Carbapenem as
monotherapy

23. Acinetobacter

24.  The name, Acinetobacter, comes from the Latin
word for "motionless," because they lack cilia or
flagella with which to move

25. INTRODUCTION
 Gram-negative pleomorphic rods
 Colonize aquatic environment
 Associated with biofilms
 Survives on inanimate surfaces for weeks
 Infections and outbreaks
 Intensive care unit and healthcare settings
 Compromised immune systems at risk
 Colonized and infected patients as point sources

26.  Mostly isolated from hospital environment
 Not part of normal human flora
 A. baumannii is often a source of nosocomial
infections
 Can reach a very high percentage of infections in ICU
settings
 Unfortunately it has the potential to often be multi-drug
resistant

27.  Resistance to multiple drugs
 - Over-expression of efflux pumps
 - Expression of ß-lactamases
(Including ESBLs and metallo-ß-lactamases which
can cause carbapenem resistance)
 This can necessitate use of drugs with greater
toxicity (such as polymyxins)

28. Genus: Acinetobacter
CLASSIFICATION
Name Genomic species No.
A. calcoacetius 1
A. baumanii 2
A. haemolyticus 4
A. junii 5
A. johnsonii 7
A. lwoffi 8
A. radioresistens 12
Unnamed (14)

29. EPIDEMIOLOGY
Habitat
Free living saprophyte in soil and water
Human colonization
25% healthy adults - cutaneous
7% healthy adults and infants - pharyngeal
Most common GNR - hospitalized patients
n Prevalence - Worldwide

30. TRANSMISSION
Acinetobacter can be spread from person to
person (infected or colonized patients), contact
with contaminated surfaces of exposure to the
environment

31. PATHOGENICITY
Virulence factors – Mostly unknown
n LPS and Capsule
n Opportunistic infections - Immunocompromised
n Growth at low pH and high and low temperatures
n Ability to survive for months on inanimate
surfaces

32. Risk factors for nosocomial infections
Prolonged hospitalization
Catheterization - Urinary or IV
Broad spectrum antimicrobials
Endotracheal intubation
Colonic colonization
Burns

33. CLINICAL MANIFESTATIONS
Nosocomial pneumonia
Catheter associated-UTI
Wound infections
Septicemia
Peritonitis
Meningitis - shunt associated
Infective endocarditis

34. LABORATORY DIAGNOSIS
Gram stain
Culture
Biochemical reactions

35. MORPHOLOGY
Gram negative rods
Pleomorphic [Coccobacilli]
Gram variability
Non-motile
Capsulated

36. CULTURAL CHARACTERISTICS
n Grows aerobically on routine culture media
n Grows at 44° C
n Colony morphology
BA: 1-2mm round, smooth, opaque, mucoid,
dome shaped, non-pigmented, hemolytic
MA: NLF with purplish hue

37. BIOCHEMICAL REACTIONS
Catalase - Positive
Oxidase - Negative
Nitrate reduction – Negative
Indole negative
Do not ferment glucose or most other sugars
Saccharolytic [A. baumanii]
Asaccharolytic [A. lwoffi]
Urease production - Some strains
Citrate utilization - Some strains

38. DIFFERENTIAL DIAGNOSIS
n Gram stain: Neisseria species
n Biochemical reactions: Enterobacteriaceae
Organism Growth Oxidize Esculin L A Nit Litmus
on MA Glucose D D
C H
Stenotrophomonas + + ± + - ± +
Acinetobacter
Sacchorylitic + + - - ± - -
Asaccharolytic + - - - ± - -
CDC Group NO-1 ± - - - - + ±

39. TREATMENT
General Principles
n Colonization vs. infection: Don’t treat colonization
with systemic antimicrobials
n Mild infections: Removal of prosthetic devices/
foreign body, antimicrobials - not required
n Superficial infections: Local management
n Moderately severe infections: Monotherapy
n Severe/extensive deep infections:
Combination therapy and debridement/drainage
n Therapeutic failure to beta-lactams:
3rd or 4th generation Cephalosporins

40. ANTIMICROBIALS
Carbapenems
[Ampicillin + Salbactam]
[Cefoperazone + Salbactam]
n 4-fluoroquinolones
n 3rd and 4th generation cephalosporins
n Aminoglycosides
n Piperacillin/tazobactam
n Doxycycline
n Co-trimoxazole
n Polymyxin B/ Colistin

41. COMBINATION THERAPY
Imipenem +/- Rifampicin
Unasyn + aminoglycoside
Carbenicillin + aminoglycoside
Quinolone + amikacin

42. PREVENTION
Isolation
Contact precautions
Ventilator care
House keeping
Local antimicrobial prescribing
policy