MICROBIAL AGENTS OF RESPIRATORY TRACTINFECTIONSDepart. of Microbiologi Medical Fac. Hasanuddin University2005

Agents of Respiratory Tract Infections Respiratory tract Infection agents:bacteria, viruses fungiparasites

MAJOR INFECTIOUS AGENTS OF UPPER RESPIRATORY DISEASE

MAJOR INFECTIOUS AGENTS OF UPPER RESPIRATORY DISEASE

MAJOR CAUSES OF ACUTE MIDDLE RESPIRATORY TRACT DISEASES

MAJOR CAUSES OF ACUTE MIDDLE RESPIRATORY TRACT DISEASES

MAJOR CAUSES OF LOWER RESPIRATORY TRACT DISEASES

MAJOR CAUSES OF LOWER RESPIRATORY TRACT DISEASES

TRANSMISSIONEndogenous : organ to organ Direct In-direct: - hematogenous - lymphogenousExogenous: man to man Direct contact: droplet Air borne transmissiaon

AIR BORNE TRANSMISSION

PREDISPOSING FACTORS

Age, Immunity dissorder, Difficulty in clearing upper respiratory secretions, Alcoholics, drug abusers, Unconsciousness, decreased laryngeal reflexes.

Haemophilus influenzae

CLASSIFICATIONGenera: Haemophilus Species: H. influenzae, H. haemolyticus; H. paraphrohaemolyticus; H. segnis; H. aphrophilus; H. ducrey, H. aegyptius, H. paraprophilusstrain H. influenzae: 6 major serotypes (a to f) - non-capsulated (R strain) 50-80% upper respiratory tract Pat. oportunistic - type b: strain capsulated (S strain) 2-4% pathogen. - type a and c-f: capsulated (1-2%) rarely incriminated as pathogens

CHARATERISTIC OF H. influaenzae Small, short rod (coccobacilllus), pleomorphicGram-negative, non-spore-formingNon-motile

Mostly non-capsulated, some with capusule (polisakharida).Facultative anaerob Fastidious: need X and V factors

VIRULENCE FACTORS Capsular polysaccharaides- anti fagositicMembrane lipopoligosac-charides-adhesion in host cellsIgA protease-inactivation IgA secretory

PATHOGENESIS

Portal of entry : upper respiratory tract nasopharinx.H influenzae type b penetrates nasopharengial epithelium either dissiminates hematogenously or spread directly to meninges.

CLINICAL MANIFESTATIONS

MeningitisOtitis media and sinusitis (young children). Acute bacterial epiglottitis (Children 2-5 yr) Cellulitis (face and neck). Bacteriemia Systemic infection (capsulated strain) meningitis or septic arthritis. Respiratory diseaseChronic bronchitisPneumonia

EPIDEMIOLOGY

a. Reservoirs - H. influenzae strictly human pathogen. - Human carrier: non-capsulated H. influenzae : . 60-90% healthy children , 35% adults. - 2% healthy children are asymptomatic carrier H. influenzae type b.b. Transmission: inhalation of infected droplet. Close contact favors transmission.

EPIDEMIOLOGY

c. Incidence. Frequency of invasive infection related to age, but infection during 2 moths of age rare (protective by mother immunity). d. Susceptibility Host-factors contributing to disease suscep tibility : 2nd humoral immune deficiency, sickle disease & chronic pulmonary infection.

LABORATORY DIAGNOSIS Specimens Upper resp. tract infection: blood Nasopharynx swabs: only for carrier. Lower Resp. tract infection: sputum, Other infection: cerebrospinal fluids

Laboratory1. Gram-stain of sputum and CSF.2. Culture.3. Particel agglutination test.

Legionella pneumophila

CLASSIFICATION

Family Legionellaceae Genera Legionella Species: L. pneumophila, L. micdadei, L. bozemanii, L. gormanii, L. dumoffii, L. jordanis, L. longbeachae, L. wadsworthii, dan L. oakridgensis.

GENERAL PROPERTIES thin, pleomorphic, Gram negatif tods difficult to stain with conventional staining , flagellated, motile produces catalase and -laktamasefastidious, microaerophilic

VIRULENCE FACTORS

Adhesion Ability to survive intracelullary: a. a peptide toxin inhibits a respiratory burst b. Produce catalase during the respiratory burst (H2O2 from phagocyte cell -- non-active) c. Unidentified factors

CINICAL MANIFESTATION

Incubation periods: 2-10 days.Legionnaires diseases: pneumonia fever, chill, head-ache, coughPontiac fever : flue like syndrome

EPIDEMIOLOGY

A. Distribution Worldwide. Exist in a wide range of physical and chemical habits, mostly aquatic. Found in water cooling tower, AC system, shower heads, and faucet B. Transmission Aquired through inhalation of airborne aerolized microorganisms. No evidence of person to person transmission.

EPIDEMIOLOGY

C. Susceptibility Several predisposing factors: including generalized immunosuppression and condition that decrease local defenses in lung (chronic diseases, smoking)Incidence: Exposure and subclinical infection rather frequent app. 20% of older US populations are sero-positive

LABORATORY DIAGNOSIS A. Specimens Tissue biopsyB. ExaminationsMicroscopic examination of sputum and tissue Isolation & identificationDNA Identification Serological test

Bordetella pertussis

CLASSIFICATIONGenera Bordetella Species: B. pertussis, B. parapertussis, B. bronchoseptica.

GENERAL PROPERTIESsmall coccobacil , Gram-negative capsulated, non-spora strict aerobe fastidious : need growth factors

PATHOGEN FACTORSAdhesinToxinsPertussis Toxin :Hipersensitivity cells to stimuli.Susceptibility to anaphylaxis .Insulin synthesis ,Leucocytosis Adenylate cylase-like toxin intracellulary cAMP & inhibits hemotaxis.Tracheal cytotoxin damage tracheal epithelium characyteristic cough .

PATHOGENESIS

Locally on upper respiratory tract, Most symptoms direct related to mucosal destruction Systemic effects: cause by either diffusion of pertussis toxin or by cross-reactive immune reaction.

CLINICAL MANIFESTION Pertussis: 3 phase: Catarrhal phaseParoxysmal phase: 6 weeks or moreConvalescence phase: 1-3 weeks

EPIDEMIOLOGY

1. Reservoir There is no animal reservoir B. pertussis strictly human pathogen2. Transmission: person to person by inhalation of droplet with bacteria 3. Insidence - Pertussis : cause significant morbidity and mortality. - With intensive immunization program insidence.4. Susceptibility - Affects mostly infants & particularly during the first 6 months of life - Morbidity & mortality rates are higher in girls.

LABORATORY DIAGNOSIS

Specimens Cough-plate SerumLab examinationsIsolation & identificartion Direct immunoflourescence methods: fast diagnosis. Enzyme immunoassay (EIA)

Streptococcus pneumoniae (PNEUMOCOCCUS)

CHARACTERISTIC OFStrept. pneumoniae Ovoid or lancet-shape cocci, Paired Gram-positive, Catalase negative-hemolyticCapsulated (polysaccharide)Facultative anaerob, microaerobicBile soluble Optochin-sensitive

CLASSIFICATION

lacks group-specific cell wall antigen can not be classified using Lancefield systemPolysaccharide capsule : antigenic 83 sero-types

VIRULENCE FACTORS

Polysaccharide capsul IgA protease

CLINICAL MANIFESTATIONSStr pneumoniae leading cause of bacterial pneumoniae in adults and children Other infections : otitis media, meningitis, sinusitis, bronchitis.

PREDISPOSING FACTORS

Impaired immune response Viral induced-immunosuppression and viral-induced tissue alteration Loss of splenic function

EPIDEMIOLOGY

Str. pneumoniae: human pathogen, no animal reservoir . Transmission: Person to person contact inhalation of contaminated droplets

LABORATORY DIAGNOSIS Specimen : Sputum, Blood, Cerebro-spnal fluids

Pemeriksaan: Rapid diagnostic tests: particle agglutination test.Isolation

Confirmation:1. Optochin sensitivity testing: inhibited by optochin. 2. Bile solubility testing soluble in bile 3. Tes Quellung

QUELLUNG TEST

Neisseria meningitidis (Meningococci)

CLASSIFICATIONFamily: Neisseriaceae,Genera: NeisseriaSpecies: Patogen: N. gonorrhoae (gonococci) dan N. meningitidis (meningococci), khas intraseluler. Normal flora: extracellular: N. lactamica, N. sicca, N. subflava, N. mucosa, N. flavascens, N. cinerea, M. catarrhalis. Identification: biochemial reaction.

GENERAL CHARACTERISTIC OF NEISSERIA Gram-negative cocciKidney-bean shape. often seen as diplococci Capsulated and piliated Aerobic, oxidase-positive, Complex growth requirement.

VIRULENCE FACTORSAdhesian factors: piliCapsule polysaccharide: antiphagocytic . Lipopolysaccharide (LPS, endotoxin) : 10 times more potent than other endotoxin IgA proteases : protect bacteria against the effect of secretory IgA

CLINICAL MANIFESTATION Febril illnesssMeningitisAcute meningococcemia: a. skin purpura, necrosis, gangren of the digits. b. Hipertention, multiple organ failure & septic shockPharyngitis, pneumonia.

LABORATORY DIAGNOSIS Specimen: Blood or cerebrospinal fluids Nasopharyngeal swab : only for carrier tracking. Bacterial diagnosis: 1. Gram preparation 2. IsolationSerology latex-agglutination test or hemagglutination test

Mycoplasma pneumoniae

CLASSIFICATION

Orde: MycoplasmatalesFamily: MycoplasmataceaeGenera: Mycoplasma & UreaplasmaSpecies : 1. Mycoplasma pneumoniae 2. Mycoplasma genitalium, 3. Mycoplasma hominis Species Ureaplasma:Ureaplasma urealyticum

MYCOPLASMA PROPERTIES

Pleomorphic, small cells Lack cell wall & do not stain with conventional bacteriologic stains. Smallest bacteria can grow in vitro, fastidious; grow slowly on complex, enriched media.Fried egg coloniesM. pneumoniae grow aerobically, other species are facultative anaerobes. Species can be easily differentiated by metabolic characteristics.

PATHOGENESIS OFM. pneumoniae

M. pneumoniae : primerily a pathogen of the respiratory tract. Once its reached the bronchi, adhesion to ciliatic mucosal epithelial cells. The central nervus system (CNS), myocardium, skin, joints, and blood may also be affected. Transmission : Man to man by respiratory tract secretion.

CLINICAL MANIFESTATIONS Incubation period: 15-25 days. Clinical diseases: pneumonia, tracheobronchitis, pharyngitis, or otitis media.Pneumonia not as serious as other bacterial pneumoniae, the patient often remain ambulatory atypical or working pneumonia: non-productive cough.

LABORATORY DIAGNOSIS Specimens Larinx or pharinx swabs, sputum, inflama-sion exudates, nose secret , urethral and genital secretions. Microbiological diagnosis1. Microscopically: Preparation smear from colony methalic blue in alcohols or fluoresence staining. 2. Isolation3. Serology testing cold-agglutinin Ab Other antibodies : Complement-fixing AbIgM Ab