Microbiology Review Flashcards
(107 cards)
1
Q
Bordetella pertussis
A
Whooping cough
Gram negative aerobic coccobacillus capsulate
Humans are only known reservoir
2
Q
Bordetella pertussis: clinical manifestations
A
Onset of symptoms 1-3 weeks after exposure
Catarrhal Phase
Paroxysmal phase - Uncontrollable expirations, followed by gasping inhalation – whooping cough, associated with post cough cyanosis, gagging, and vomiting
Convalescent Phase -Reduction in frequency and severity of cough can last from weeks to months
3
Q
Bordetella pertussis: treatment
A
Supportive
Azithromycin
Chemoprophylaxis to control outbreaks
4
Q
Klebsiella pneumonia
A
Gram negative, non-motile, capsulate rods
Facultative anaerobes
UTI, soft tissue infections, endocarditis, central nervous system infections, and severe bronchopneumonia.
Community and hospital acquired pneumonias
Cavitary lung lesions
Currant Jelly sputum
5
Q
Moraxella catarrhalis
A
Gram negative bacteria that grows well on blood or chocolate agar diplococci Catalase positive Oxidase positive Pneumonia, especially in the elderly Otitis media in young children
6
Q
Neisseria meningitidis
A
Aerobic gram negative kidney shaped diplococci, capsule
Oxidase positive, ferments maltose and glucose Grows on Thayer-Martin media, chocolate agar
7
Q
Neisseria meningitidis: clinical manifestations
A
Meningitis
Septicemia
Pneumonia
Septic arthritis, pericarditis, chronic bactermia, or conjunctivitis
8
Q
Neisseria meningitidis: treatment & prevention
A
Penicillin
3rd generation cephalosporin
Chemoprophylaxis with rifampin in close contacts
Meningococcal polysaccharide-protein conjugate vaccines
9
Q
Neisseria meningitidis: prognosis
A
Untreated systemic disease with 70-90% mortality
10% mortality with treatment
Morbidity
Limb loss, hearing loss, long-term neurologic disability
10
Q
Pseudomonas aeruginosa
A
Aerobic gram-negative rod
Produces pyocyanin on laboratory medium – blue/green pigment
Primarily nosocomial pathogen
In hospital can colonize moist surfaces of the axilla, ear, and perineum
11
Q
Pseudomonas aeruginosa: infections
A
HAP, VAP
Community acquired infections related to hot tubs, whirlpools, swimming pools, and extended contact lenses
Otitis externa
Puncture wounds through tennis shoes
Endopthalmitis – complication of eye surgery
Endocarditis, from sharing contaminated needles
UTI
Skin Infections, burns, ecthyma gangrenosum
12
Q
Pseudomonas aeruginosa: Host & Bacterial Factors
A
Host Factors – Neutropenia increases risk
Bacterial Factors
exotoxins, endotoxins, type III secreted toxins, pili, flagella, proteases, phospholipases, iron-binding proteins, exopolysaccharides, the ability to form biofilms, and elaboration of toxic small molecules such as pyocyanin
13
Q
Pseudomonas aeruginosa: treatment
A
Extended spectrum penicillin and aminoglycoside combination
14
Q
Chlamydophila psittaci
A
Gram negative obligate intracellular bacteria Macrophages are the principal host cell Diseases Psittacosis Atypical pneumonia Febrile illness Transmission - Aerosolized bird secretions, dust Diagnosis - Serology
15
Q
Chlamydophila psitacci: treatment & prevention
A
Treatment : tetracyclines, macrolides, fluoroquinolones
Prevention
30 day quarantine for all imported psittacine birds and their treatment with feed containing chlortetracycline
16
Q
Chlamydophila pneumoniae
A
80% of adults are seropositive
Common infection in children under 5 years old
Atypical pneumonia
Incubation several weeks
Non productive cough
Preceded by nasal congestion, sore throat, and hoarseness
Headaches in ½ of patients
17
Q
Chlamydophila pneumoniae: PE
A
Examination Crackles, rhonchi Chest x-ray Pneumonitis Labs Normal white count Prolonged course over several weeks
18
Q
Chlamydophila pneumoniae: treatment
A
Tetracyclines
Macrolides
Fluoroquinolones
19
Q
Coxiella burnetii
A
Gram negative that infects hosts monocytes
Will multiply in immunocompromised patients and endocarditis patients despite high antibody levels
Infects mammals, birds, and ticks
Mammals infected by aerosols and may shed Coxiella in feces, urine, milk, and birth products
Survives in environment and can be spread by the wind
20
Q
Coxiella burnetii: Q fever
A
Prolonged fever, pneumonia, hepatitis, rash
Meningitis, encephalitis, meningoencephalitis, peripheral neuropathy
Pericarditis, myocarditis
Chronic uterine infection during pregnancy, may later experience multiple spontaneous abortions
Q-fever endocarditis
Intermittent fever
Vegetations frequently absent
Cerebral emboli, renal insufficiency, splenomegaly, hepatomegaly
21
Q
Coxiella burnetii: treatment
A
Doxycycline x 2 weeks in acute cases
Doxycycline + hydroxychloroquine(increases phagosomal pH) for 18-36 months for endocarditis
22
Q
Francisella tularensis
A
Small aerobic pleomorphic gram-negative bacillus
Not communicated person to person
Extreme risk to lab personnel
23
Q
Francisella tularensis: Ulceroglandular
A
Fever and constitutional symptoms Swollen lymph nodes that drain an inoculation site Ulcer formation Sore throat Patchy infiltrates on chest x-ray
24
Q
Francisella tularensis: Glandular & Typhoidal
A
Glandular
Fever
Constitutional symptoms
Lymphadenopathy
Typhoidal
Fever of unknown cause
25
Francisella tularensis: Oropharyngeal Disease
Uncommon in the United States
Mucous membranes of the mouth and pharynx are the portal of entry
Contaminated water or food such as inadequately cooked game meat is the source
Painful exudative pharyngitis and tonsillitis
Pharyngeal ulcers
Swollen retropharyngeal and cervical lymph nodes
26
Francisella tularensis: Pneumonic disease
Inhalation exposure
Fever, malaise, dry cough, substernal discomfort, pleural effusion, dyspnea, and sore throat
Chest x-ray with peribronchial infiltrates to bronchopneumonia with effusion
Hilar adenopathy
27
Fransicella tularensis: treatment
Gentamcin or streptomycin
Doxycycline
Ciprofloxacin
28
Bacillus anthracis
Spore forming gram-positive non motile rod, aerobic or facultatively anaerobic, catalase positive, hemolysis negative
Grows on sheep agar
Zoonotic infection
Animal related products include meat, wool, hides, bones, and hair
Soil contaminated with spores
29
Bacillus anthracis: clinical manifestations
```
Inhalation
Mediastinal adenopathy
Mediastinal widening
Pleural effusion
Rapidly fatal if not treated
Meningeal
Nearly always fatal, can occur as complication of inhalation, cutaneous , or gastrointestinal disease
```
30
Bacillus anthracis: treatment, prevention, prognosis
```
Treatment
Multi-drug regimen
Pleural drainage
Prevention
Vaccination for possible exposure
Post-exposure antibiotics
Prognosis
45% mortality of inhalation in 2001 attacks
20% mortality in untreated cutaneous disease
```
31
Yersinia pestis
Gram negative coccobacillus, microaerophilic, nonmotile, and non spore forming
Transmission cycles involve rodents and fleas, which act as vectors.
Prairie dogs are a common host
32
Bubonic Plague
Swollen, tender lymph nodes (buboes) closest to site of initial infection
Fevers, chills, myalgia, arthralgia, headache, malaise, and prostration
Untreated patients have continued fever, tachycardia, agitation, confusion, delirium, and convulsions
33
Septicemic Plague
Nausea, vomiting, diarrhea, and abdominal pain
Disseminated intravascular coagulation
Hypotension, renal failure, and obtundation
ARDS
34
Pneumonic Plague
Fever, cough, chest discomfort, tachycardia, dyspnea, bacteria laden sputum, chills, headache, myalgias, weakness, and dizziness
Respiratory distress, hemoptysis, cardiopulmonary insufficiency, and circulatory collapse
Death within2 24 hours of symptoms
35
Yersinia pestis: treatment
Streptomycin for pneumonic plague
Tetracyclines for bubonic plague
Chloramphenicol for meningitis
36
Leptospirosis
```
Spirochete with terminal hook
Identified on dark field microscopy or silver staining
Obligate aerobe
Clinical Manifestations
Weil’s Disease:
Pulmonary Hemorrhage Syndrome
```
37
Leptospirosis: early clinical manifestations
```
First 3-7 days
Fever, myalgia, and headache
Nausea, vomiting, abdominal pain, diarrhea, cough, and photophobia
Muscle tenderness
Rash
Conjunctival suffusion
```
38
Leptospirosis: Late Phase-Weil’s Disease
```
Jaundice
Acute hemorrhage
Renal Failure
Severe thrombocytopenia
GI bleeding
Pulmonary Hemorrhage
Myocarditis
Aseptic meningitis
```
39
Leptospirosis: diagnosis, treatment, prevention
```
Diagnosis
Agglutination test
Treatment
Doxycycline
Penicillin
Prevention
Doxycycline post-exposure
```
40
Haemophilus influenzae
Encapsulated gram negative pleomorphic rod
Aerobic or facultative anaerobic
Grows on chocolate agar
Factor X(hemin) and Factor V(NAD)
Nasopharynx of adults and children
H influenza type b was most common cause of meningitis in young children prior to effective vaccines
41
Haemophilus influenzae: meningitis
Children under 5 years old and in adults with skull trauma or CSF leaks
Type B strains
Diagnosis made by detecting PRP capsular antigens in CSF
42
Haemophilus influezae: epiglottitis
Life threatening infection in children that usually occurs in children younger than 5.
Symptoms include fever, drooling, dysphagia, and respiratory distress with stridor
Course is rapid over a couple of hours
Lateral neck film used for diagnosis
43
Haemophilus influenzae: pneumonia & bronchitis
```
Pneumonia:
Fever, cough, and lobar consolidation
Parapneumonic effusion and empyema
Diagnosed by blood culture or culture from pleural fluid
Smoking – risk factor
Bronchitis
Risk factor is chronic lung disease ( COPD)
Acute Sinusitis
Otitis Media
```
44
Haemophilus influenzae: treatment & prevention
Treatment:
3rd generation cephalosporin for meningitis
Prevention
Conjugate capsular polysaccharide-protein vaccine effective for type b disease
Antibiotic prophylaxis in nonimmunized household or daycare contacts of patients with H influenza type b
Rifampin
45
Corynebacterium diptheriae
```
Gram-positive bacillus – club shaped
Non-spore forming
Aerobic
Reservoir:
Throat and pharynx
Transmission:
Bacterium or phage via respiratory droplets
```
46
Respiratory Diptheria
Incubation of 1-7 days
Sore throat, malaise, and fever
Pharyngeal erythema followed by tonsillar exudate
Exudate changes into a grayish membrane that is tightly adherent and bleeds on attempted removal
47
Corynebacterium diptheriae: clinical
Cervical adenopathy – Bull Neck
Stridor
Extension of membrane can lead to airway obstruction
Myocariditis, recurrent laryngeal nerve palsy, and peripheral neuritis
48
Corynebacterium diptheriae: treatment & prevention
```
Treatment:
Erythromycin
Antitoxin
Prevention:
Vaccination with toxoid vaccine
```
49
Legionella pneumophila
Weakly gram-negative pleomorphic rod
Facultative intracellular
Requires cysteine and iron ( Charcoal yeast extract)
Water organism, amebae, air-conditioning water cooler tanks
No human to human transfer
Risk Factors: smokers over age 55 with high alcohol intake and immunosuppression
50
Legionaire’s disease
Fevers, malaise, cough, chills , dyspnea, myalgias, headache, chest pain, and diarrhea.
Myalgias, severe headaches, and diarrhea distinguish it from other pneumonias
Mental Confusion
51
Pontiac Fever
Fever, sore throat myalgia, headache, and extreme fatigue
| Short duration, lasting on average 3 days
52
Legionella pneumophila: diagnosis & treatment
Diagnosis
Antigen urine test
DFA ( direct fluorescent antibody)
Treatment
Fluoroquinolones, azithromycin, or erythromycin + rifampin for immunocompromised patients
Drug must penetrate human cells
53
Mycoplasma pneumonia
Smallest free-living bacteria
No cell wall – unaffected by cell-wall inhibiting antimicrobials such as B-lactams
Sterol containing membrane
Requires cholesterol for culture
Transmission: respiratory droplets, close contact, families, military recruits, dorms
Highest incidence age 5-20 years old
54
Mycoplasma pneumonia: clinical manifestations
```
Respiratory Infection
2-3 weeks incubation
Fevers, malaise, headache, and cough
5-10% progress to tracheobronchitis or pneumonia
Cough usually non-productive
Walking pneumonia
Bullous myringitis
```
55
Mycoplasma pneumoniae: diagnosis & treatment
Diagnosis
Positive cold agglutinins - positive in 65% of cases
Treatment
Macrolides: erythromycin, azithromycin, and clarithromycin
Tetracyclines
56
Streptococcus pneumonia
Gram positive diplococcus, lancet shaped
Facultative anaerobe, grows on blood agar plates
alpha hemolytic
Optochin sensitive
Lysed by bile
Reservoir – human upper respiratory tract
Transmission – respiratory droplets
57
Streptococcus pneumonia: patho
Pathogenesis:
Polysaccharide capsule
Risk Factors
Influenzae infection, COPD, CHF, Alcoholism, and asplenia
Pathobiology
Initially colonizes the nasopharynx then aspirated
58
Streptococcus pneumonia: clinical manifestations
```
Typical Pneumonia
Most common cause
Shaking chills, high fever, chills, rigors, lobar consolidation, blood tinged (rusty) sputum
Adult meningitis
Most common cause in adults
Otitis media and sinusitis
Most common cause in children
```
59
Streptococcus pneumonia: treatment
Treatment of pneumonia
Beta lactams
Macrolides
Fluoroquinolones
Treatment of meningitis
3rd generation cephalosporins
Vancomicin added if penicillin resistant
60
Severe Acute Respiratory Syndrome (SARS)
Coronavirus – second most common cause of the common cold
Reservoir: birds and small mammals
Virus is also found in urine, sweat, and feces
Original case thought to be transmitted from animal to human
61
SARS: clinical manifestations
```
Fever greater than 100.4 F
Flu-like illness
Dry cough
Dyspnea
Progressive hypoxia
```
Diagnosis
Clinical history and history of travel to endemic area or association with a traveler
Travel to far east or Toronto.
62
SARS: treatment
Treatment is supportive
| Mortality is 50% in the elderly
63
Varicella-Zoster Virus
Reservoir – human mucosa and nerves
Transmission – respiratory droplets
Virus infects epithelial cells and lymphocytes in the oropharynx and upper respiratory tract, then infected lymphocytes spread the virus throughout the body.
The virus enters the skin through endothelial cells in blood vessels and spreads to epithelial cells where it causes a vesicular rash.
Virus remains dormant in the cranial nerve ganglia and dorsal root ganglia. Reactivation of virus leads to Herpes zoster .
64
Varicella-Zoster Virus: treatment
Shingles – oral acyclovir
Immunocompromised with shingles – IV acyclovir
Aspirin contraindicated due to Reye’s syndrome
65
Varicella-Zoster Virus in immunocompromised
Vaccine contraindicated in hematologic malignant neoplasms, AIDS, HIV infection with CD4 count of 200/mm3 or lower, and in persons receiving high dose immunosuppressive therapy, or anti-tumor necrosis factor –a therapy.
VZIG (varicella-zoster immunoglobulin) post exposure prophylaxis of immunocompromised patients
66
Staphylococcus aureus
```
Gram positive cocci in clusters
Catalase positive
Coagulase positive
Beta hemolytic
Small yellow colonies on blood agar
Ferments mannitol
```
67
Staphylococcus aureus: virulence
Over 50 virulence factors including adhesins, toxins, enzymes, surface-binding proteins, and capsule polysaccharides
Pathogenesis from tissue invasion and toxin mediated
3 toxin mediated diseases
Staphylococcal food poisoning
Staphylococcal toxic shock syndrome
Staphylococcal scalded skin syndrome
68
Staphylococcus aureus: clinical manifestations
Skin manifestations include impetigo, folliculitis, furuncle, abscess, erysipelas, cellulitis, mastitis, necrotizing fasciitis, and wound infections
Bacteremia
Endocarditis
Roth’s spots, Osler’s nodes, Janeway lesions, and petichiae
Pericarditis
Osteomyelitis – hematogenous seeding
Septic Arthritis, Infected prosthetic joints
Pneumonia – nosocomial pneumonia, salmon colored sputum
69
SA Toxin Mediated Diseases
Food poisoning – Enterotoxins A-E
2-6 hours after eating nausea, vomiting, diarrhea, and abdominal pain; Self limited
Toxic Shock Syndrome TSST-1 a super antigen
Fever, erythroderma, hypotension, involvement of 3 or more organ systems, and desquamation of the palms and soles
Scalded Skin Syndrome – exfoliative toxin A or B
70
Staphylococcus aureus: treatment
Gastroenteritis is self limiting
Nafcillin/Oxacillin
MRSA – Vancomicin
71
Pnemocystis jirovecii
Fungus
Obligate extracellular parasite
Silver stain
Opportunistic infection in HIV patients with CD4 count less than 200
72
Pneumocystis jerovecci: pneumonia
Fever, nonproductive cough, and shortness of breath
X-ray with patchy infiltrate, ground glass appearance, lower lobe and periphery may be spared
Diagnosis : silver staining cysts in bronchial alveolar lavage fluids or biopsy
Treatment sulfamethaxazole/trimethoprim or dapsone
Prevention SMX/TMP prophylaxis for CD4 counts less than 200 in HIV patients
73
Histoplasma capsulatum
Dimorphic fungus
Facultative intracellular parasite – found in RES cells
Found in soil, caves, and abandoned buildings with bird and bat guano
Transmission - Disruption of soil; cleaning attics, bridges, and barns; tearing down old structures, and spelunking
Endemic to Mississippi and Ohio River Valleys
74
Histoplama capsulatum: clinical manifestations
Acute pulmonary
Most asymptomatic
Several weeks after exposure fevers, chills, fatigue, non-productive cough, anterior chest discomfort, and myalgias
Chronic pulmonary
Progressive, often fatal
Elderly, immunocompromised, and COPD patients at risk
75
Histoplamsa capsulatum: PE & treatment
X-ray
Acute Pneumonia with patchy lobar or multilobar infiltrate
Chronic Pneumonia with upper lobe infiltrates, multiple cavities, fibrosis of lower lobes – mimics TB
Treatmet
Itraconazole
Amphotericin B
76
Coccidiodes immitis
Dimorphic fungi
Inhaled arthroconidia enlarge and form spherules
Spherules undergo internal septation producing endospores
Endemic in southwest deserts
77
Coccidiodes immitis: pulmonary infection
Symptoms develop 5-21 days after exposure
Fever, weight loss, fatigue, dry cough, and pleuritic chest pain
Arthralgias
Erythema nodosum
Chest x-ray with pulmonary infiltrates, hilar adenopathy, and peripneumonic effusion
Pulmonary Nodule, cavitary
78
Coccidiodes immitis: treatment
Disseminated infection
Immunocompromised , e.g. AIDS
3rd trimester pregnancy
Skin, joints, and bones
Treatment
Itraconazole
Amphotericin B
79
Paramyxoviruses
```
Enveloped, helical nucleocapsid
Negative-sense ssRNA
Parainfluenza
Measles
Mumps
RSV
```
80
Parainfluenza
Transmission by large particle fomites and close person-to-person contact
Most children exposed by start of elementary school
Coryza, rhinorrhea, pharyngitis without lymphadenopathy, and low grade fever
Symptoms usually last 3-5 days
Signs of lower tract infection present as croup
81
Parainfluenza: clinical
Croup
Raspy, barking cough with inspiratory stridor, dyspnea, and respiratory distress
Symptoms result from subglottic inflammation and edema
Bronchiolitis or Pneumonia
Cough, rales, wheezing, and hypoxia
Cold
Reinfection of adults with parainfluenza typically causes cold symptoms in normal adults and children
82
Measles – Rubeola
Highly contagious
3 C’s cough, coryza, conjunctivitis
Generalized maculopapular rash
Fever
Transmission by direct contact with large respiratory droplets
Infectious 4 days prior to rash until 4 days after onset of rash
83
Measles – Rubeola: clinical
Incubation 8-12 days
Prodrome of fever, cough, coryza, conjunctivitis, and Koplik spots
Malaise, myalgia, and headache
Koplik spots proceed rash by 1 day and are resolved 2 days into rash
Rash typically starts 2-6 days after the onset of catarrhal symptoms and starts on face or behind ears as individual macules. Rash coalesces, forms papules and progresses from head to trunk to extremities. Rash covers entire body by 4 days. Fades in same order.
84
Measles – Rubeola: complications
Diarrhea, otitis media, and pneumonia
Postinfectious encephalomyelitis
2 weeks after rash with onset of headache, recurrence of fever, vomiting, stiff neck
25% mortality
33% of survivors with neurologic sequelae
Subacute sclerosing panencephalitis
Degenerative demyelinating disease due to chronic infection.
Occurs years after the acute measles infection and is universally fatal
85
Measles - Rubeola: treatment
Treatment is supportive
Prevention
Live, attenuated vaccine - MMR
86
Mumps
Transmission droplet spread of upper respiratory secretions
Incubation 18 days
Clinical Manifestations
Parotitis
Aseptic Meningitis – common and usually mild
Encephalitis rare and severe
Orchitis
Treatment – supportive
Prevention – live, attenuated vaccine - MMR
87
Respiratory Syncytial Virus
Epidemics begin in late fall in southern states and peak in February and March in colder climates
60% of bronchiolitis and 25% of pneumonia in infants
Transmission
Direct contact with large-particle fomites of respiratory secretions
88
RSV: Clinical Manifestations - infants
Conjunctival injection, mucopurulent nasal discharge, cough, low-grade fever
Otitis Media
Lower respiratory symptoms in 25-50% of infants with cough, wheezing, tachypnea, use of accessory muscles, and cyanosis.
Expiratory wheezing, rhonchi, and fine rales on lung examination
Chest x-ray
Hyperinflation and diffuse interstitial pneumonitis
89
RSV: treatment
Treatment – Ribavarin
Prevention
Frequent handwashing
No vaccination available
90
Strongyloides stercoralis
Exposed skin comes in contact with free-living filiariform larvae living in contaminated soil. After skin penetration, larvae enter the afferent circulation and travel to the pulmonary vasculature, where they rupture into the alveolar spaces, ascend the respiratory tree, and are swallowed into the GI tract. Development into adult worms occurs in the upper part of the small intestine. Female worms begin laying eggs. Eggs hatch in the lumen of the small intestine. Rhabditiform larvae migrate to the colon and are passed in the feces.
91
Strongyloides stercoralis: clinical
Pulmonary Manifestations
Can be severe in immunocompromised
Resembles ARDS with acute onset of dyspnea, productive cough, and hemoptysis accompanied by fever, tachypnea, and hypoxemia
Treatment - ivermectin
92
Aspergillosis
Ubiquitous organisms found in soil, decaying matter, and air.
Spore like conidia are aerosolized from the mold form of the organism.
They reach tissue and form invasive hyphae.
Can be isolated from basements, crawl spaces, bedding, humidifiers, ventilation ducts, potted plants, dust, condiments, and marijuana
93
Invasive Aspergillosis
```
Immunocompromised host
Fever
Pulmonary infiltrates
Nodules
Wedge-shaped densities resembling infarcts
Sinusitis
Extrapulmonary sites
CNS abscesses, endophthalmitis, MI, GI, renal, osteomyelitis, endocarditis
```
94
Invasive Aspergillosis: diagnosis & treatment
Diagnosis: BAL, needle aspiration, thoracoscopic biopsy, or open lung biopsy
Treatment
Antifungal- Voriconazole or liposomal amphotericin B
Reversal of immunosuppression
Surgical resection of infected lesions
95
Chronic Pulmonary Aspergillosis
Aspergilloma
Ball in cavity
Debris in preformed cavity from TB, Histoplamosis, or fibrocystic sarcoidosis
Treatment
Limited benefit with aspergilloma
Antifungal – itraconazole or voriconazole in chronic cavitary pulmonary aspergillosis
96
Allergic Bronchopulmonary Aspergillosis (ABPA)
History of chronic asthma or cystic fibrosis
Airway obstruction, fever, eosinophilia, positive sputum cultures, mucous plugs containing hyphae, brown flecks in sputum, transient infiltrates, proximal bronchiectasis, upper lobe contraction, elevated IgE.
Eosinophilia in blood, sputum, and lung tissue
97
Allergic Pulmonary Aspergillosis: diagnosis & treatment
```
Asthma
Immediate cutaneous reaction to A. fumigatus antigen
Serum IgE greater than 1000 ng/ml
A. fumigatus specific serum IgE levels
Precipitating serum antibodies to A. fumigatus
Central bronchiectasis
Peripheral eosinophilia
Pulmonary infiltrates
Treatment
Corticosteroids and itraconazole
```
98
Cryptococcosis
Occurs most often in the immunosuppressed – HIV
Meningitis is most common clinical manifestation
Pulmonary and other organ involvement can occur
Cryptococcus neoformans
Yeast
Environment and tissues
Polysaccharide capsule is the major virulence factor
99
Cryptococcus in immunocompromised
Patients at highest risk are those with AIDS and CD4 counts less than 50.
Inhaled from the environment and causes pulmonary infection initially. Most patient asymptomatic.
If the host becomes immunosuppressed the organism can reactivate and disseminate to other sites.
C. neoformans is neurotropic
100
Cryptococcus: meningoencephalitis
```
Headaches over several weeks
Nuchal rigidity
Lethargy
Personality changes
Confusion
Visual abnormalities
Nausea and vomiting
```
101
Cryptococcosis: Pulmonary Infection
Risk factors include COPD, Corticosteroid use, and solid organ transplant
Fever, cough, and dyspnea
Treated with antifungals
102
Cryptococcosis: diagnosis
Yeast is grown in culture from CSF, Blood, sputum, skin lesions, or other body fluids
India Ink stain – visualization of budding yeast with large capsule
Latex agglutination for Cryptococcal polysaccharide antigen
103
Cryptococcosis: treatment of CNS infections
Non-AIDS Patients
Amphotericin B and flucytosine for 6 weeks
AIDS Patients
Amphotericin B and flucytososine for 2 weeks, followed by fluconazole 400 mg daily for 8 weeks, then suppressive therapy with fluconazole 200 mg daily
104
Cytomegalovirus
Member of herpesvirus family
Double stranded DNA genome
Latent infections
Most clinical disease caused by reactivation of latent virus in the immunocompromised host.
Hallmark pathology is large central basophilic intranuclear inclusion “Owls eye”
105
Cytomegalovirus: clinical
Congenital and Neonatal
Microcephaly, intracerebral calcification, hepatosplenomegaly, and rash
Mental retardation and hearing loss
Mother with primary infection during pregnancy
Immunocompetent Most asymptomatic, few with mono like illness
106
Cytomegalovirus in immunocompromised
```
Transplant Recipients
Fever, neutropenia, atypical lymphocytes, and hepatosplenomegaly
Hepatitis – transplanted liver
Pneumonia
Colitis - diarrhea
AIDS
CD4 counts less than 50
Retinitis
Colitis
```
107
Cytomegalovirus: diagnosis, treatment, prevention
```
Diagnosis
Culture
CMV Antigen or nucleic acid detection
Serology
Prevention
Reducing exposure to body fluids, “safe sex”
Treatment
Antivirals
```
