airborne infection

AIRBORNE INFECTION

AIRBORNE INFECTIONS:

Contracted by inhalation of microorganisms or

spores suspended in air on water droplets or

dust particles

RESPIRATORY TRACT INFECTIONS

Infections involving the respiratory tracts

Classified as an upper respiratory tract or a lower

respiratory tract infections 

Lower respiratory infections, such as pneumonia,

tend to be far more serious conditions than upper

respiratory infections, such as the common cold

URTI

Infections in the: Nose

Sinuses

Pharynx

Larynx

Middle ear

URTI TYPICAL INFECTIONS Tonsillitis Pharyngitis Laryngitis Sinusitis (can be cause by fungi) Otitis media (can be cause by fungi) Influenza Common cold

SYMPTOMS OF URTIS Cough Sore throat Runny nose Nasal congestion Headache Low grade fever Sneezing

FUNGAL INFECTIONS OF THE UPPER RESPIRATORY TRACTS

FUNGAL INFECTIONS OF THE UPPER RESPIRATORY TRACTS Fungal Ear infections

Fungal nasal sinusitis

Fungal infections of the oral cavity

Fungal keratitis

FUNGAL EAR INFECTIONS“OTOMYCOSIS”Otitis externa & Otitis media

OTITIS EXTERNA

Fungal infection of the external ear canal

World-wide, but more common in tropical and sub-tropical regions

ETIOLOGY Caused mainly by:

Aspergillus fumigatus

Aspergillus niger

Candida albicans

Candida tropicalis

OTHER CAUSES MAY INCLUDE

Malassezia species

Pseudallescheria boydii

Absidia species

Acremonium species

Penicillium species

Rhizopus species

Scopulariopsis brevicaulis

CLINICAL MANIFESTATION Inflammation Itching Scaling Discomfort Masses of debris containing hyphae Pain

Otitis Externa

LABORATORY DIAGNOSIS Direct examination of epithelial debris

Hyphae and in some instances the fruiting structures of the etiologic agent

Culture: Sabouraud dextrose agar incubated at 30°C

(without cycloheximide)

MANAGEMENT

Removal of debris and cleaning

Topical azole cream

Gauze packs soaked in amphotercib B +

natamycin or imidazole

FUNGAL PARANASAL SINUSITIS

FUBGAL PARANASAL SINUSITIS

Sinusitis caused by different fungi

Especially in patients with a history of allergic rhinitis or immunosuppression

CAUSATIVE AGENTS Dematiaceous fungi (phaeohyphomycosis):

Bipolaris species Curvularia species Alternaria species

Non Dematiaceous fungi (haylohyphomycosis): Aspergillus species Zygomycetes

Curvularia geniculata (Atlas of Clinical Fungi, De Hoog et al. 2000)

Curvularia lunata

Bipolaris

Alternaria

Zygomycetes

Zygomycetes

Zygomycetes in tissues

MANAGEMENT OF PARANASAL SINUSITIS

Surgery

Antifungal (Amphotericin B or Azoles)

ORAL THRUSHOral candidiasis or candidosis

ORAL CANDIDIASIS OR CANDIDOSIS (ORAL THRUSH) Over growth of C. albicans in the oral cavity Whitish removable layer cover reddish,

eroded, easily bleeding mucosa May extend to the esophagus Mainly seen in:

Prolonged use of broad spectrum antibiotics Impaired T-cell immunity

Oral candidiasis

TREATMENT

For healthy adults and children

Eating unsweetened yogurt

Taking acidophilus capsules or liquid

For adults with weakened immune

systems

Azoles

Amphotericin B

KERATOMYCOSISmycotic keratitis

KERATOMYCOSIS Corneal infection caused by either filamentous fungi or

yeast The most important risk factors:

Trauma (generally with plant material) Chronic ocular surface diseases Contact lens usage Surgery Eye-drops abuse Immunodeficiencies

Condition related to warm climates

Keratitis

Fungi type Moulds Yeasts

Predisposing factors • Outdoor or vegetable-related trauma

• Contact lens usage • Eye surgery

• Chronic ocular surface diseases

• Chronic mucocutaneous candidiasis

• Immunosuppression, including AIDS

• Corneal anesthetic abuseMost common

etiologic agents

• Fusarium spp • Aspergillus spp • Acremonium • Other

• Candida albicans • Candida parapsilosis • Candida tropicalis

EPIDEMIOLOGICAL AND CLINICAL DIFFERENCES BETWEEN THE TWO FORMS OF THE INFECTION

LABORATORY DIAGNOSIS Microscopic examination

Hyphae in corneal scrapings

Fungi are usually deep within the corneal structure, not on the surface.

Extensive debridement may be necessary to obtain satisfactory clinical material (swabs are unsatisfactory)

Septate hyphaeThe fungus was seen in several repeated corneal samplings

MANAGEMENT

Drug of choice is Natamycin

Amphotericin B a second alternative

Systemic therapy with azoles

Surgery may be necessary

LOWER RESPIRATORY TRACTS INFECTIONS

LOWER RESPIRATORY TRACTS INFECTIONS

Generally more serious than upper

respiratory infections

The leading cause of death among

all infectious diseases

The two most common LRIs: Bronchitis and pneumonia

PNEUMONIA

Pneumonia is an inflammatory condition of

the lung

Especially affecting the microscopic air sacs

(alveoli)

Associated with fever, chest symptoms, and a

lack of air space (consolidation) on a chest X-ray

CAUSES

Microbial infections: Bacteria, 

Viruses

Fungi

Parasites

Other causes

TYPICAL SYMPTOMS Cough

Chest pain

Fever

Difficulty breathing

DIAGNOSIS

X-rays

Sputum examination

CLASSIFICATION Community-acquired Aspiration Hospital-acquired Ventilator-associated pneumonia

Lobar pneumonia Bronchial pneumonia

By the causative organism

CAUSATIVE AGENTS Viruses and bacteria (most common) Fungi and parasites (less common)

Mixed infections with both viruses and bacteria: Up to 45% of infections in children 15% of infections in adults

Causative agent is not isolated in approximately half of cases

FUNGAL PNEUMONIA

FUNGAL PNEUMONIA

Uncommon

Occur in individuals with weakened immune

systems due to: AIDS

Immunosuppressive drugs

Other medical problems

FUNGAL SPECIES Opportunistic:

Aspergillus species Candida species Pneumocystis jiroveci

Primary: Histoplasma capsulatum Blastomyces dermatitidis Coccidioides immitis 

ASPERGILLUS SPECIES Pulmonary Aspergillosis:

Allergic, aspergilloma and invasive aspergillosis

The common etiological agents are: Aspergillus fumigatusAspergillus flavusAspergillus nigerAspergillus nidulansAspergillus terreus

Aspergillosis of the lung Methenamine silver stained tissue section showing

dichotomously branched, septate hyphae (left) and a conidial head of A. fumigatus (right)

Aspergillus species

OTHER OPPORTUNISTIC FUNGAL INFECTIONS:CANDIDA SPECIES

C. albicans (50-60 % of all yeast infections)

C. glabrata C. tropicalis C. parapsilosis

Candida albicans in the lung of an immunocompromised patient, PAS stain

Pneumocystis jiroveci

PNEUMOCYSTIS JIROVECII

 Yeast-like fungus of the genus Pneumocystis

Pneumocystis  pneumonia

Prior to its discovery as a human-specific pathogen, P. Jirovecii was known as P. carinii

PATHOGENICITY AND CLINICAL SIGNIFICANCE Pneumocystis is one of the major causes of

opportunistic mycoses in immunocompromised

Clinical forms: Asymptomatic infections Infantile (interstitial plasma cell) pneumonia Pneumonia in immuno-compromised host Extra-pulmonary infections

DIAGNOSIS OF P. JIROVECI PNEUMONIA

Depend of morphologic identification

Culture is difficult

Trophic (trophozoite)

Intracystic spores

Pneumocystis jiroveci morphology

The cysts of P. jiroveci are spherical in shape and measure approximately 4-7 µm

Gomori's Methenamine Silver Stain

X 1000

Cysts of Pneumocystis jiroveci in lung tissue GMS stain

The walls of the cysts are stained black and often appear crescent shaped or like crushed ping-pong

balls

Pneumocystis jiroveci and artifacts

Yeast cells Pneumocystis jiroveci

Pneumocystis in induced sputum; wright stain stains

trophozoites

Pneumocystis in bronchoalveolar lavage;

toluidine blue highlights cyst forms

END