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Arthur Dessi Roman MD MTM FPCP FPSMID
Internal Medicine – Infectious Diseases
Outline
• Basic Bacteriology
– Structure a...
3
Highschool recall: Eukaryotes
• Eukaryote - organism whose cells contain complex
structures enclosed within membranes
– ...
4
Size comparison of cells
Bacterium
Bacterial cell structure
5
Prokaryotes Eukaryotes
Simple structure Membrane-bound structures
(nucleus, mitochondria)
Plasmids
Peptidoglycan that st...
6
Generalities
• Most cocci are gram positive
• Most bacilli are gram negative
Gram positive Bacilli/rods
• Bacillus sp.
–...
7
Gram negative cocci
• N. meningitides, N. gonorrhea
• Acinetobacter spp.
• Coccobacilli:
– Pasteurella multocida
– Borde...
8
Identify
Identify
9
Bacterial morphology
Gram staining
10
11
The Gram Stain
• Quick procedure that reveals bacterial cell
morphology (cocci vs. bacilli, G+ vs G-)
• Gram negative: ...
12
Rise of the superbugs
Resistance of bacteria to antibiotics after their liberal
use in hospitals may be assimilated by ...
13
Gram-positive & Gram-negative cell wall
Gram + Gram -
Cell wall made of thick
peptidoglycan
Thin peptidoglycan
No outer...
14
Bacterial cell wall peptidoglycan
PBPs
• Penicillin-binding proteins (PBPs) catalyze the
synthesis of the PG in the cel...
15
Beta-Lactams
Sulbactam
• A beta-lactamase inhibitor
• Binds to B-lactamase irreversible B-lactamase
canNOT deactivate ...
16
Beta-Lactams
Meropenem
17
(Livermore and Woodford, Trends in Microbiol, 2006)
The Gram Negative Cell Wall
Porin
channels
PBPs
Efflux system
B-lac...
18
BETA-LACTAM ANTIBIOTIC
S. aureus
mecA gene
DNA
SCC
PBP2A
MRSA
19
Anaerobic vs. aerobic bacteria
• Aerobic: need oxygen to grow
• Anaerobic: fail to grow in the presence of oxygen
• Obl...
20
Spot Quiz
What are single-celled, prokaryotic
microorganisms that sometime produce disease
in humans and are usually su...
21
What is the rigid structure outside the cell
membrane which protects and maintains the
shape of bacteria?
Answer: CELL ...
22
What are the proteins that facilitate formation
of peptidoglycans?
Answer: PENICILLIN-BINDING PROTEINS
(PBPs)
What is t...
23
Differentiate the call walls of gram-positive and
gram-negative cell walls.
Answer: Gram-negative cell walls have an ou...
24
The outer membrane of gram-negative bacteria
act as a barrier to some antibiotics, but
antibiotics and other nutrients ...
25
Bacterial reproduction via binary fission
Bacterial culture
26
Bacterial Identification
• Subsequent bacterial identification is based
from initial Gram staining results from
bacteri...
27
Normal Flora
28
Bacterial growth curve
Pathogens
• Microorganisms causing disease
• Pathogenicity: ability to cause disease
(increased ...
29
Host Defenses
Types of Infection
Acute: Chronic:
- develop rapidly - develop more slowly
- usually associated with feve...
30
Types of Infection
• Bacteremia: presence of bacteria in the blood.
• Septicemia: blood poisoning; systemic disease ass...
31
Symptoms of Infection
• Provide subjective information on patient’s condition.
• Inflammation: Process that occurs in t...
32
Signs of Infection
• Elevated blood levels of C-reactive protein.
• Increase in pulse rate, respiration rate, anxiety, ...
33
Non-specific immunity: cilia
Non-specific immunity: phagocytes
34
Specific immunity: antibodies
Specific immunity: T cells
35
Spot quiz(zes)
What do you call the microorganisms that
normally live in our bodies?
Answer: NORMAL FLORA
36
What do you call a microorganism that cause
disease?
Answer: PATHOGEN
What do you have when bacteria invade body
tissue...
37
What do you call the body’s response to
infection?
Answer: IMMUNITY
What is the importance of knowing the normal
flora ...
38
Antibiotic Classes
32
Case 1
• 35/male who was admitted for severe
abdominal pain and fever.
• Took paracetamol but did...
39
32
Case 1
• A> Acute appendicitis  underwent OR
• He was discharged improved.
• On ff-up with the surgeon after 5 days...
40
Staphylococcus aureus
• frequently found in the human respiratory tract and on
the skin
• NOT always pathogenic
• Cause...
41
Coagulase and Staphylokinase
Staphylokinase
Staphylokinase
Clotting protein
36
Hyaluronidase (Spreading factor)
Hyaluro...
42
Clinical manifestation of S. aureus infection
38
40
43
Staphylococcus aureus
1. Local Stap. Infection – drainage
> antibiotics –semi synthetic PCN
Cloxacillin Erythromycin
Ce...
44
Question
What is the current MRSA rate in the Philippines
according to the ARSP 2014?
A. <5%
B. 35%
C. 60%
D. 90%
Perce...
45
Percent resistance of S. aureus,
(n=3,529), ARSP, 2014
ANTIMICROBIAL RESISTANCE SURVEILLANCE PROGRAM (ARSP) 2014 ANNUAL...
46
Enterococci
• Gram-positive cocci in chain
44
Enterococci
• Gram-positive cocci in chain
• Commensals of the GI tract o...
47
Vancomycin-Resistant
Enterococci (VRE)
46
• An emerging pathogen but none yet in PH
• Acquired via plasmids
• Cephalosp...
48
32
Case 2
• Treated as stroke and underwent rehab after 5
days doing well
• On Day 6 cough and difficulty of breathin...
49
Pseudomonas aeruginosa
•Aerobic gram-negative bacilli, non-
spore forming
•Produces cyanin pigment
•Produces grape-like...
50
• MOST important hospital-acquired pathogen
• Other pseudomonads: Burkholderia mallei,
Burkholderia cepacia
•High tende...
51
23
• Causes nosocomial infections- extensive burns, trauma
to the skin or conjunctiva, urinary tract manipulations
• cy...
52
Treatment
• Aminoglycosides
• Third and fourth generation cephalosporins
(ceftazidime, cefepime)
• Carbapenems (imipene...
53
32
Case 3
• 15/male with cerebral palsy recurrently
admitted for pneumonia
• He already has a tracheostomy tube in plac...
54
Case 3
• After 3 days of antibiotics, he was still febrile
• Developed hypotension and further
respiratory distress
Cas...
55
Acinetobacter
• Aerobic gram-negative coccobacilli,
non-spore forming
• > 25 species
• A common cause of ventilator-
as...
56
A. baumannii
Persistence in the hospital
environment : 3 days to 5 months
1. Resistance to major antimicrobial
drugs
2....
57
A. baumannii
Treatment:
• Meropenem
• Colistin
• Tigecycline
• Ampicillin-Sulbactam
31
Acinetobacter
• Aerobic gram-neg...
58
A. baumannii
Clinical manifestation of A. baumannii
infection1.Hospital-acquired pneumonia
especially VAP
2.Community-a...
59
A. baumannii
31
A. baumannii
Treatment:
• Meropenem
• Colistin
• Tigecycline
• Ampicillin-Sulbactam
31
60
Enterobactereaceae
• Gram-negative, nonspore-forming rods
• Facultative anaerobic
• Grow in simple media (MacConkey aga...
61
*Proteus Group
– P. mirabilis
– P. vulgaris
– Morganella – M. morganii
– Providencia – P. rettgeri
*Edwardsiella – E. h...
62
Epidemiology
• Fecal-oral transmission transmission among infants in
hospital nurseries.
• Food-borne transmission of E...
63
Gram’s Stain and Culture
Klebsiellae
• Encapsulated
• The species of Klebsiella include
- Klebsiella pneumoniae- most i...
64
• Mucoid colony
• มีแคปซูลหนา
Klebsiella
18
Diseases:
• Community acquired and nosocomial
pneumonia w/ underlying medic...
65
• Hypermotile
• Swarming
growth
Proteus vulgaris
66
Enterobacteriaceae: Treatment
• Empiric therapy with aminoglycoside and
third cephalosporin
Case 4
• 35/female who just...
67
Case 4
• She underwent EL on Day 3
• Doing well
• Day 10 of meropenem and clinda, developed
high fever
• No cough. No d...
68
Laboratory Diagnosis
• Culture of stool specimens
• Cytotoxin Assay
– Tissue culture assay
– immunoassays
• Colonoscopy...
69
• Drug of choice
– Metronidazole (30 mg/day in 4 divided
doses) – drug of choice in the initial
treatment of most patie...
70
Case 5
• Labs done: WBC 20 Neut 90%
• Chest xray: normal
• Urinalysis: WBC 50 RBC 0-3 EC few yeast cells
few
• Started ...
71
Candida spp.
• normal flora of the skin, mucous membranes, and
gastrointestinal tract
• colonize the mucosal surfaces o...
72
Systemic Candidiasis (Candidemia)
• Causes:
– indwelling catheters, surgery, intravenous drug abuse,
aspiration, or dam...
73
Outline
• Basic Bacteriology
– Structure and Characteristics
– Bacterial Culture
• Host defenses
• Gram positive Pathog...
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World of Microbes

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World of Microbes

  1. 1. 1
  2. 2. 2 Arthur Dessi Roman MD MTM FPCP FPSMID Internal Medicine – Infectious Diseases Outline • Basic Bacteriology – Structure and Characteristics – Bacterial Culture • Host defenses • Cases – Gram positive Pathogens – Gram negative Pathogens – Bonus(es) • Question and Answer Portion • Sportswear Competition
  3. 3. 3 Highschool recall: Eukaryotes • Eukaryote - organism whose cells contain complex structures enclosed within membranes – the defining membrane-bound structure is the nucleus, which contains the genetic material – also contain other membrane-bound organelles: mitochondria, chloroplasts and the Golgi apparatus – e.g. animals, plants and fungi Highschool recall: Prokaryotes • Prokaryote - NO cell nucleus , or any other membrane-bound organelles. – DNA and other sites of metabolic activity: openly accessible, free-floating – asexual reproduction, usually by binary fission or budding – Genetic exchange and recombination still occur, but this is a form of horizontal gene transfer and is NOT a replicative process, simply involving the transference of DNA between two cells, as in bacterial conjugation.
  4. 4. 4 Size comparison of cells Bacterium Bacterial cell structure
  5. 5. 5 Prokaryotes Eukaryotes Simple structure Membrane-bound structures (nucleus, mitochondria) Plasmids Peptidoglycan that strengthens bacterial cell wall Bacterial morphology
  6. 6. 6 Generalities • Most cocci are gram positive • Most bacilli are gram negative Gram positive Bacilli/rods • Bacillus sp. – Normal flora of the skin – B. anthracis, B. cereus • Lactobacillus (shirota strain et al) • Corynebacterium • Clostridium sp. • Listeria • Erysipelothrix
  7. 7. 7 Gram negative cocci • N. meningitides, N. gonorrhea • Acinetobacter spp. • Coccobacilli: – Pasteurella multocida – Bordetella pertussis – Legionella Identify
  8. 8. 8 Identify Identify
  9. 9. 9 Bacterial morphology Gram staining
  10. 10. 10
  11. 11. 11 The Gram Stain • Quick procedure that reveals bacterial cell morphology (cocci vs. bacilli, G+ vs G-) • Gram negative: red/pink • Gram positive: violet/blue • The color difference is based on the amount of the peptidoglycan layer (G+=thick = more dye uptake=blue/violet color) • Results guide initial antibiotic therapy The Prokaryotic genome has many plasmids. • encode genes that carry specialized functions (eg. Resistance to bacteria) • Also encode for genes that mediate their transfer from one organism to another as well as other genes associated with genetic acquisition or rearrangement of DNA.
  12. 12. 12 Rise of the superbugs Resistance of bacteria to antibiotics after their liberal use in hospitals may be assimilated by plasmids of other non-resistant bacteria Gram-positive vs Gram-negative cell wall
  13. 13. 13 Gram-positive & Gram-negative cell wall Gram + Gram - Cell wall made of thick peptidoglycan Thin peptidoglycan No outer membrane Outer membrane present No endotoxin contains LPS/ Lipid A/ endotoxin responsible for sepsis More susceptible to penicillins (lysozymes, detergents, etc.) due to absence of outer layer Outer membrane provides barrier has porins for entry of nutrients NO periplasmic space Periplasmic space contains B- lactamase/other enzymes that may degrade antibiotics Possess teichoic acids NO teichoic acids
  14. 14. 14 Bacterial cell wall peptidoglycan PBPs • Penicillin-binding proteins (PBPs) catalyze the synthesis of the PG in the cell wall • B-lactam antibiotics work by inhibiting PBPs • Some bacteria produce enzymes that alter the PBPs or inactivate the B lactam ring  resistance
  15. 15. 15 Beta-Lactams Sulbactam • A beta-lactamase inhibitor • Binds to B-lactamase irreversible B-lactamase canNOT deactivate the beta-lactam ring
  16. 16. 16 Beta-Lactams Meropenem
  17. 17. 17 (Livermore and Woodford, Trends in Microbiol, 2006) The Gram Negative Cell Wall Porin channels PBPs Efflux system B-lactamases Mechanism of Resistance to β-lactams CELL WALL PENICILLIN BINDING PROTEIN (cell wall synthesis) S. aureus
  18. 18. 18 BETA-LACTAM ANTIBIOTIC S. aureus mecA gene DNA SCC PBP2A MRSA
  19. 19. 19 Anaerobic vs. aerobic bacteria • Aerobic: need oxygen to grow • Anaerobic: fail to grow in the presence of oxygen • Obligate anaerobes: grow only in aerobic environment • Facultative anaerobes: can grow with or without oxygen • Microaerophilic bacteria: grow best in an environment with reduced oxygen • Aerotolerant: can grow in the presence of air, but do NOT use oxygen Important Bacterial Pathogens Bacteria Gram positive* Gram negative* Atypical Cocci Bacilli Cocci Bacilli *can be aerobic/anaerobic
  20. 20. 20 Spot Quiz What are single-celled, prokaryotic microorganisms that sometime produce disease in humans and are usually susceptible to antibiotics? Answer: BACTERIA
  21. 21. 21 What is the rigid structure outside the cell membrane which protects and maintains the shape of bacteria? Answer: CELL WALL What is the main component of bacterial cell walls? Answer: PEPTIDOGLYCAN
  22. 22. 22 What are the proteins that facilitate formation of peptidoglycans? Answer: PENICILLIN-BINDING PROTEINS (PBPs) What is the procedure that can help visualize bacteria under the microscope and differentiate them into gram-positive and gram-negative bacteria? Answer: GRAM STAIN
  23. 23. 23 Differentiate the call walls of gram-positive and gram-negative cell walls. Answer: Gram-negative cell walls have an outer membrane made up of a thinner layer of peptidoglycan and an outer membrane, which is in turn made up of lipopolysacharide or endotoxin. What is the enzyme that can degrade beta lactam antibiotics found in the periplasmic space of gram-negative bacteria? Answer: BETA LACTAMASE
  24. 24. 24 The outer membrane of gram-negative bacteria act as a barrier to some antibiotics, but antibiotics and other nutrients can enter the bacteria via “holes” called: Answer: PORINS Differentiate aerobes from anaerobes. Answer: Aerobes are bacteria that need oxygen to grow, while anaerobes are bacteria that cannot grow in the presence of oxygen.
  25. 25. 25 Bacterial reproduction via binary fission Bacterial culture
  26. 26. 26 Bacterial Identification • Subsequent bacterial identification is based from initial Gram staining results from bacteria from isolated colonies on agar plate • Subsequent testing uses bacterial nutritional requirement and metabolic capacities • Most bacteria will grow in 24-48 hours except for fastidious or anaerobes which may require more time. • Culture/identification is performed so a physician can come up with a diagnosis and prescribe the most appropriate antibiotic.
  27. 27. 27 Normal Flora
  28. 28. 28 Bacterial growth curve Pathogens • Microorganisms causing disease • Pathogenicity: ability to cause disease (increased by the presence of bacterial enzymes and bacterial toxins) • Stages of infection: adherence, invasion, multiplication, dissemination in the host
  29. 29. 29 Host Defenses Types of Infection Acute: Chronic: - develop rapidly - develop more slowly - usually associated with fever - milder symptoms - generally of short duration - longer-lasting Acute infections may become chronic, chronic infections may become acute. Local: Systemic: - Limited to one site - throughout the body Local infections may occasionally cause systemic symptoms or may serve as nucleus for spread of infection to other body areas (e.g. dental infection).
  30. 30. 30 Types of Infection • Bacteremia: presence of bacteria in the blood. • Septicemia: blood poisoning; systemic disease associated with presence and persistence of pathogenic microorganisms or their toxins in the blood. Phases of Infection 1. Invasion: Bacteria gain entry into the host, or host tissues, where it’s not part of normal flora. 2. Incubation: Period before any manifestation of illness. It represents the time required for pathogens to multiply to a critical population size. Patient can be infectious. 3. Prodrome: Period characterized by nonspecific symptoms (e.g. headache, malaise). 4. Clinical illness: Period when specific symptoms (fever) appear. Body damage may result due to toxin, death of host cells, actions of host’s immune system. 5. Convalescence or Resolution: Period of recovery, even without symptoms patient may still be infectious.
  31. 31. 31 Symptoms of Infection • Provide subjective information on patient’s condition. • Inflammation: Process that occurs in tissues as a reaction to injury. It involves vasodilation, increased permeability of capillaries to fluid and large molecules, and attraction and accumulation of WBCs and other immune system components in injured area. - Results in pain, swelling, heat and throbbing. • Fever: Not true in all infections. Microbes produce pyrogens (fever-causing substances) that cause release of cytokines that cause the fever. • Symptoms depend on organs or systems affected and are helpful to MDs in diagnosing specific conditions. Signs of Infection • Provide objective measures of disease; vary depending on nature and severity of condition. • Fever: Both a sign and symptom. • Increased number of neutrophils in blood. • Increased in proportion of immature WBC (shift to the left). • Neutropenia or granulocytopenia: abnormally, low neutrophils in overwhelming, severe infections. (Normal value: 1,500-7,800 /mL). The incidence of infection rises as neutrophil count declines. • Anemia: reduction below normal in number of RBCs per mm3, hemoglobin, or volume of packed RBC per 100 ml of blood. • Increased ESR (erythrocyte sedimentation rate) which measures the rate at which RBCs settle in uncoagulated blood – a non-specific measure of inflammation or disease activity.
  32. 32. 32 Signs of Infection • Elevated blood levels of C-reactive protein. • Increase in pulse rate, respiration rate, anxiety, confusion, delirium, and other abnormalities in mental status. • Hyperglycemia: elevated blood sugar levels, especially in diabetics. • Changes in kidney and liver function. Non-specific host defenses • Directed against any pathogen • Mechanical • Chemical • Phagocytes and complement system
  33. 33. 33 Non-specific immunity: cilia Non-specific immunity: phagocytes
  34. 34. 34 Specific immunity: antibodies Specific immunity: T cells
  35. 35. 35 Spot quiz(zes) What do you call the microorganisms that normally live in our bodies? Answer: NORMAL FLORA
  36. 36. 36 What do you call a microorganism that cause disease? Answer: PATHOGEN What do you have when bacteria invade body tissues, multiply in them, and cause damage to the host’s cells? Answer: INFECTION
  37. 37. 37 What do you call the body’s response to infection? Answer: IMMUNITY What is the importance of knowing the normal flora in terms of dealing with infections? Answer: It helps in determining EMPIRIC THERAPY.
  38. 38. 38 Antibiotic Classes 32 Case 1 • 35/male who was admitted for severe abdominal pain and fever. • Took paracetamol but did not improveER • PE: febrile, direct and rebound tenderness RLQ
  39. 39. 39 32 Case 1 • A> Acute appendicitis  underwent OR • He was discharged improved. • On ff-up with the surgeon after 5 days, STAPHYLOCOCCUS
  40. 40. 40 Staphylococcus aureus • frequently found in the human respiratory tract and on the skin • NOT always pathogenic • Causes skin infections (e.g. boils), respiratory disease (e.g. sinusitis), and food poisoning • Producing potent toxins • Common cause of device-related infections • Carriage in healthy individuals (nostrils) • The emergence of antibiotic-resistant forms of pathogenic S. aureus (e.g. MRSA) is a worldwide problem in clinical medicine. Staphylococcus aureus • Virulence factors – Coagulase – Staphylokinase – Hyaluronidase
  41. 41. 41 Coagulase and Staphylokinase Staphylokinase Staphylokinase Clotting protein 36 Hyaluronidase (Spreading factor) Hyaluronidase digests hyaluronic acid, the “glue” that holds cells together 37
  42. 42. 42 Clinical manifestation of S. aureus infection 38 40
  43. 43. 43 Staphylococcus aureus 1. Local Stap. Infection – drainage > antibiotics –semi synthetic PCN Cloxacillin Erythromycin Cehalosporin (1st gen.) 2. Systemic Infection: Parenteral Vancomycin Oxacillin Methiallin Cephalosporin Question What is the current MRSA rate in the Philippines according to the ARSP 2014? A. <5% B. 35% C. 60% D. 90%
  44. 44. 44 Question What is the current MRSA rate in the Philippines according to the ARSP 2014? A. <5% B. 35% C. 60% D. 90% Percent resistance of S. aureus, (n=3,529), ARSP, 2014 ANTIMICROBIAL RESISTANCE SURVEILLANCE PROGRAM 2014 ANNUAL REPORT FIGURE 32. Yearly penicillin, oxacillin and vancomycin resistance rates of S. aureus, ARSP, 2005-2014 ANTIMICROBIAL RESISTANCE SURVEILLANCE PROGRAM (ARSP) 2014 ANNUAL REPORT, Research Institute for Tropical Medicine, Department of Health Philippines
  45. 45. 45 Percent resistance of S. aureus, (n=3,529), ARSP, 2014 ANTIMICROBIAL RESISTANCE SURVEILLANCE PROGRAM (ARSP) 2014 ANNUAL REPORT, Research Institute for Tropical Medicine, Department of Health Philippines Percent resistance of S. aureus, ARSP, 2014 ANTIMICROBIAL RESISTANCE SURVEILLANCE PROGRAM 2014 ANNUAL REPORT Antimicrobial Resistance The 2014 resistance rate of S. aureus against the β-lactam oxacillin is at 60.3% (n=3,323; 95% CI: 58.6-62). The 2014 rate of methicillin-resistant S. aureus (MRSA) rates increased significantly from 53.2% in 2013 to the 60.3% in 2014 (p value 0.0001). Resistance rates against the antibiotics tested against S. aureus for 2014 and the past decade are see n FIGURES 40-43. The 2014 resistance rates to the rest of the antibiotics tested did not differ significantly from the reports from 2013 except for the significant increase in co-trimoxazole resistance from 14% in 2013 to 22% for 2014 (p value 0.0001). Although there were 17 isolates reported as vancomycin resistant, none of these S. aureus isolates were sent for confirmatory testing at the reference laboratory. FIGURE 30. Percent resistance against penicillins, vancomycin, clindamycin and erythromycin of S. aureus, ARSP, 2014 ANTIMICROBIAL RESISTANCE SURVEILLANCE PROGRAM (ARSP) 2014 ANNUAL REPORT, Research Institute for Tropical Medicine, Department of Health Philippines • Overall cumulative MRSA rate for 2014 was at 60.3% (from 53.2%, p=0.0001) • 85% were isolated from specimens taken from patients in the OPD, emergency room and admission within their 1st 2 hospital days • 60% MRSA rate from all blood isolates (n=570)
  46. 46. 46 Enterococci • Gram-positive cocci in chain 44 Enterococci • Gram-positive cocci in chain • Commensals of the GI tract of humans & animals • Diseases : • Consist of 16 species :- E. faecalis, E. faecium - Urinary tract infection (UTI) - Bacteremia, endocarditis 44
  47. 47. 47 Vancomycin-Resistant Enterococci (VRE) 46 • An emerging pathogen but none yet in PH • Acquired via plasmids • Cephalosporin use is a risk factor • Can be carried by healthy people 32 Case 2 • 65/male DM, HPN admitted for sudden left sided weaknessER • PE: no motor movement left UE and LE, shallow right NSLF, slurred speech
  48. 48. 48 32 Case 2 • Treated as stroke and underwent rehab after 5 days doing well • On Day 6 cough and difficulty of breathing, high fever, auscultation revealed rales on right lung field • Eventually intubated due to respiratory distress Case 2 • Started empirically on PipTazo • ETA GS revealed many PMNs and many Gram _____________.
  49. 49. 49 Pseudomonas aeruginosa •Aerobic gram-negative bacilli, non- spore forming •Produces cyanin pigment •Produces grape-like odor •Inhabitant of the GI tract •Saprophytic (natural habitat: soil and water) •An opportunistic pathogen Pseudomonas aeruginosa •
  50. 50. 50 • MOST important hospital-acquired pathogen • Other pseudomonads: Burkholderia mallei, Burkholderia cepacia •High tendency to develop antibiotic resistance Pseudomonas aeruginosa 21 Resistance Pattern of P. aeruginosa, ARSP 2011
  51. 51. 51 23 • Causes nosocomial infections- extensive burns, trauma to the skin or conjunctiva, urinary tract manipulations • cystic fibrosis. • Ear infections – swimmer’s ear • Bacteremia in debilitated patients, accounts for 10% of all Gram(-) associated with a 50% mortality rate Pseudomonas aeruginosa 21
  52. 52. 52 Treatment • Aminoglycosides • Third and fourth generation cephalosporins (ceftazidime, cefepime) • Carbapenems (imipenem, meropenem) • Pip-tazo • Colistin Pseudomonas aeruginosa Clinical manifestation of P. aeruginosa infections
  53. 53. 53 32 Case 3 • 15/male with cerebral palsy recurrently admitted for pneumonia • He already has a tracheostomy tube in place • Developed progressive cough and respiratory distressER 32 Case 3 • PE: drowsy, highly febrile, rales all over R>L • Hooked to MV and started on Pip-Tazo
  54. 54. 54 Case 3 • After 3 days of antibiotics, he was still febrile • Developed hypotension and further respiratory distress Case 4 • EC = few PMN=moderate • Gram negative diplococci-few • Gram negative coccobacilli-many
  55. 55. 55 Acinetobacter • Aerobic gram-negative coccobacilli, non-spore forming • > 25 species • A common cause of ventilator- associated pneumonia (VAP) • Opportunistic pathogen 28 • Local isolates are very highly resistant to antibiotics A. baumannii Clinical manifestation of A. baumannii infection1.Hospital-acquired pneumonia especially VAP 2.Community-acquired pneumonia :The source of infection may be throat carriage, which occurs in 10% of community residents with excessive alcohol consumption 3.Bloodstream infection & endocarditis 4.Skin/soft tissue infection 5.UTI 6.Meningitis 29
  56. 56. 56 A. baumannii Persistence in the hospital environment : 3 days to 5 months 1. Resistance to major antimicrobial drugs 2. Resistance to desiccation 3. Resistance to disinfectant Three factors contributing to the persistence 31 A. baumannii 31
  57. 57. 57 A. baumannii Treatment: • Meropenem • Colistin • Tigecycline • Ampicillin-Sulbactam 31 Acinetobacter • Aerobic gram-negative coccobacilli, non-spore forming • > 25 species • A common cause of ventilator- associated pneumonia (VAP) • Opportunistic pathogen 28 • Local isolates are very highly resistant to antibiotics
  58. 58. 58 A. baumannii Clinical manifestation of A. baumannii infection1.Hospital-acquired pneumonia especially VAP 2.Community-acquired pneumonia :The source of infection may be throat carriage, which occurs in 10% of community residents with excessive alcohol consumption 3.Bloodstream infection & endocarditis 4.Skin/soft tissue infection 5.UTI 6.Meningitis 29 A. baumannii Persistence in the hospital environment : 3 days to 5 months 1. Resistance to major antimicrobial drugs 2. Resistance to desiccation 3. Resistance to disinfectant Three factors contributing to the persistence 31
  59. 59. 59 A. baumannii 31 A. baumannii Treatment: • Meropenem • Colistin • Tigecycline • Ampicillin-Sulbactam 31
  60. 60. 60 Enterobactereaceae • Gram-negative, nonspore-forming rods • Facultative anaerobic • Grow in simple media (MacConkey agar) • Ferment glucose (LF) • Motile with peritrichous flagella except Shigella • Some possess capsule Impt. Human pathogens • Escherichia - E. coli • Enterobacter (E. aerogenes, E. cloacae) • Citrobacter - C. freundii • Serratia - S. marcescens • Hafnia - H. alvei • Klebsiella
  61. 61. 61 *Proteus Group – P. mirabilis – P. vulgaris – Morganella – M. morganii – Providencia – P. rettgeri *Edwardsiella – E. hoshinae Escherichia coli • Escherichia coli and certain related bacteria (e.g., Klebsiella, Enterobacter, Citrobacter) form the group known as the coliforms • presence in drinking water is considered evidence of fecal contamination • used as an index of fecal pollution.
  62. 62. 62 Epidemiology • Fecal-oral transmission transmission among infants in hospital nurseries. • Food-borne transmission of E. coli 0157:H7 - contaminated meat, from cattle; this serotype behaves as a zoonotic agent. • UTI –perineum; In women, UTI is associated with sexual activity, hence the term "honeymoon cystitis". Diseases associated with Escherichia coli: • Diarrhea • Meningitis – impt. cause of neonatal meningitis in the neonates • Sepsis • Urinary Tract Infection -most common cause
  63. 63. 63 Gram’s Stain and Culture Klebsiellae • Encapsulated • The species of Klebsiella include - Klebsiella pneumoniae- most infections -Klebsiella oxytoca -Klebsiella ozaenae -Klebsiella rhinoscleromatis
  64. 64. 64 • Mucoid colony • มีแคปซูลหนา Klebsiella 18 Diseases: • Community acquired and nosocomial pneumonia w/ underlying medical problems such as alcoholism, COPD or diabetes mellitus • Lung abscess may also develop. • Urinary tract infection • Wound infection • Epidemic diarrhea - newborns • Septicemia
  65. 65. 65 • Hypermotile • Swarming growth Proteus vulgaris
  66. 66. 66 Enterobacteriaceae: Treatment • Empiric therapy with aminoglycoside and third cephalosporin Case 4 • 35/female who just delivered a baby boy via NSD 1 week ago rushed back to the ER for severe hypogastric pain • PE: highly febrile, direct tenderness at the hypogastric area, purulent vaginal discharge • Diagnosis? • Started on meropenem and clindamycin (MRSA)
  67. 67. 67 Case 4 • She underwent EL on Day 3 • Doing well • Day 10 of meropenem and clinda, developed high fever • No cough. No dysuria but she was having LBM 5-7x/day • Diagnosis? Clostridium Difficile • Gm (+) bacillus, obligate anaerobe • Spore forming contact precautions • Causes pseudomembranous colitis and antibiotic-associated diarrhea
  68. 68. 68 Laboratory Diagnosis • Culture of stool specimens • Cytotoxin Assay – Tissue culture assay – immunoassays • Colonoscopy or Signoidoscopy with Biopsy Endoscopic findings – pseudomembranes and hyperemic rectal mucosa Treatment • Antimicrobial therapy should be discontinued • Maintenance of fluid & electrolyte balance • Avoid drugs which intestinal motility
  69. 69. 69 • Drug of choice – Metronidazole (30 mg/day in 4 divided doses) – drug of choice in the initial treatment of most patients with colitis – Oral Vancomycin (40 mg/kg/day in 4 divided doses) – indicated only for seriously ill patients or those who do not respond to vancomycin – Bacitracin – ssecond alternative therapeutic choice Case 5 • 70/female post stroke and chronically bed ridden was admitted for decreased sensorium • Because of urinary incontinence, has been on foley catheter and PEG for episodes of aspiration • PE: drowsy, T 37 C BP 70/50 HR 100 • Clear breath sounds, no nuchal rigidity
  70. 70. 70 Case 5 • Labs done: WBC 20 Neut 90% • Chest xray: normal • Urinalysis: WBC 50 RBC 0-3 EC few yeast cells few • Started on Ceftriaxone 1g IV q24h • FC was changed • Urine GS CS requested Case 5 • Urine GS: PMN many yeast cells few G+cocci in clusters many
  71. 71. 71 Candida spp. • normal flora of the skin, mucous membranes, and gastrointestinal tract • colonize the mucosal surfaces of all humans during or soon after birth • Candida albicans – the most common pathogen • Others: C albicans, C tropicalis, C parapsilosis, C glabrata, C guilliermondii, and C dubliniensis) • The widespread use of fluconazole has precipitated the emergence of more azole-resistant species, such as C krusei and C lusitaniae. Cutaneous & Mucosal Candidiasis • The risk factors: AIDS, pregnancy, diabetes, young or old age, birth control pills, and trauma (burns, maceration of the skin), corticosteroids or antibiotics, hyerglycemia, and cellular immunodeficiency • Cutaneous candidiasis- when the skin is weakened by trauma, burns, or maceration. Vulvovaginitis - irritation, pruritus, and vaginal discharge; often preceded by factors such as diabetes, pregnancy, or antibacterial drugs that alter the microbial flora, local acidity, or secretions.
  72. 72. 72 Systemic Candidiasis (Candidemia) • Causes: – indwelling catheters, surgery, intravenous drug abuse, aspiration, or damage to the skin or gastrointestinal tract • most often associated with: – chronic administration of corticosteroids or other immunosuppressive agents; with hematologic diseases such as leukemia, lymphoma, and aplastic anemia; or with chronic granulomatous disease Candidiasis: Treatment • Systemic candidiasis: amphotericin B with/without oral flucytosine, fluconazole, or caspofungin
  73. 73. 73 Outline • Basic Bacteriology – Structure and Characteristics – Bacterial Culture • Host defenses • Gram positive Pathogens • Gram negative Pathogens • Bonus(es) 감사합니다!!!! ㅋㅋㅋ
  • MichaelPrades

    Nov. 28, 2018

by Dr. Arthur Dessie E. Roman

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