Respiratory Tract Infections - Bacteria and Viruses - PDF

MIKROBIOLOGI SALURAN PERNAFASAN dr Ranthi,Sp.MK dr. Ni Luh Ranthi Kurniawathi, Sp.MK Dept. Biomedik Undiksha/Laboratorium Mikrobiologi Klinik RSUD Buleleng 2023 SALURAN NAFAS dr Ranthi,Sp.MK SISTEM...

MIKROBIOLOGI SALURAN PERNAFASAN dr Ranthi,Sp.MK dr. Ni Luh Ranthi Kurniawathi, Sp.MK Dept. Biomedik Undiksha/Laboratorium Mikrobiologi Klinik RSUD Buleleng 2023 SALURAN NAFAS dr Ranthi,Sp.MK SISTEM PERNAPASAN THE MOST ACCESSIBLE SYSTEM IN THE BODY Breathing brings in clouds of potentially infectious pathogens. dr Ranthi,Sp.MK THE BODY HAS A VARIETY OF HOST DEFENSE MECHANISMS. Innate immune response -the cells and mechanisms that defend the host from infection by other organisms, in a non-specific manner Adaptive immune It is adaptive immunity because the body's immune system prepares itself for future challenges.  BARRIERS OF RESPIRATORY TRACT TO INFECTION dr Ranthi,Sp.MK nasal hair mucociliary cells that line mucosal surfaces coughing secretory immunoglobulin normal biota (normal flora) phagocytic inflammatory cells defensins  Role of Normal Flora dr Ranthi,Sp.MK Normal flora of the nasopharynx and oropharynx helps protect the host by preventing colonization by pathogenic organisms Can prevent proliferation and invasion of pathogenic organisms through competition for the same nutrients and the same receptor sites on host cells Produce bacteriocins, bacterial products that are toxic to potential pathogens Stimulates cross-protective immune factors known as natural antibodies cont’ -Pathogens of the respiratory system Some pathogens are restricted to certain sites. Legionella only infects the lung. Other pathogens cause infection in multiple sites. Streptococcus can cause: Middle ear infections. Sinusitis. Pneumonia.  Virulence Factors of Microbes involved in RTI Adherence Primary step in process of infection Mediated by adhesins or other microbial surface molecules or organelles Specific bacterial adhesins interact with specific cellular receptors Toxin Evasion of Host Defense S. pneumoniae, H. influenzae, and mucoid Pseudomonas aeruginosa, evade host defenses by expressing polysaccharide capsules that prevent phagocytosis by host leukocytes. Chlamydiae are obligate intracellular parasites that are taken up by host cells M. tuberculosis, another intracellular pathogen, survives by inhibiting phagosome-lysosome fusion Upper Respiratory Tract Infections Bacteria infecting the respiratory system SPECIMEN COLLECTION dr Ranthi,Sp.MK Respiratory Tract: Throat Swab Push the tongue using spatula Swab both tonsil and pharynx, avoid to touch tongue or uvula Respiratory Tract: Nasal swab Insert swab 1 cm into the nose Rotate the swab, let it 10- 15 sec Insert to transport medium (Amies medium) www.thechelmsford.co.uk Respiratory Tract: Sputum Collect sputum, not saliva! Sputum, expectorated sputum, inhalation Gurgle (minimize oral flora contamination), deep coughing Sterile container, wide mouth, screw-capped Respiratory Tract: Sputum for Mycobacterium Sputum Sputum: (Sewaktu dan Pagi/ SP) Acid Fast Bacilli (AFB) staining (Ziehl Neelsen staining) Sterile, wide-mouth, screw- capped container 3-5 ml Bacterial Detection: Gram staining Microscopy: Gram staining result MICROSCOPY: ZIEHL NEELSEN (ZN) STAINING FOR AFB MICROSCOPY: ZIEHL NEELSEN (ZN) STAINING FOR AFB DETECTION OF BACTERIA TYPE Detected by Blood Agar Cultures Hemolytic Reactions: Blood agar is a solid growth medium that contains red blood cells. The medium is used to detect bacteria that produce enzymes to break apart the blood cells. This process is also termed hemolysis. The degree to which the blood cells are hemolyzed is used to distinguish bacteria from one another.  Beta Hemolysis  Complete Hemolysis  Clear Zone Around Colonies on Blood Agar  Alpha Hemolysis  Incomplete Hemolysis  Greenish Zone Around Colonies on Blood Agar Gamma Reaction:  Absence of a Hemolytic Reaction  No Change Around Colonies on Blood Agar Microbiological/ Bacterial Culture: Type of hemolysis Observed on blood agar plate Gram positive cocci: Beta (clear zone): S. pyogenes Alpha (greenish zone): S. pneumoniae Gamma: no hemolysis BACTERIAL INFECTIONS OF THE UPPER RESPIRATORY TRACT BACTERIAL INFECTIONS OF THE UPPER RESPIRATORY TRACT Laryngitis & Epiglottitis Otitis media, mastoiditis, and sinusitis Pharyngitis Scarlet fever Diphtheria LARYNGITIS & EPIGLOTTITIS Laryngitis is swelling and irritation (inflammation) of the voice box (larynx) that is usually associated with hoarseness or loss of voice-Haemophilus influenzae & Streptococcus pneumoniae, could be fungal and viral. Epiglottitis- Inflammation of the cartilage that covers the trachea (windpipe)- Haemophilus influenzae, Streptococcus pneumoniae or Streptococcus pyogenes. OTITIS (URT) Otitis media- general term for infection or inflammation of the ear- fluid/exudates/pus/in the middle ear due to Haemophilus influenzae, Streptococcus pneumoniae or Streptococcus pyogenes. OTITIS MEDIA, MASTOIDITIS, AND SINUSITIS  Middle ear, mastoid cavity, and sinuses are connected to the nasopharynx.  Sinuses and eustachian tubes have ciliated epithelial cells. ◦ A virus initially invades the ciliated epithelium. ◦ This destroys the ciliated cells, allowing bacteria to invade.  Mastoiditis is uncommon but very dangerous. Mastoid cavity is close to the nervous system and large blood vessels.  Sinusitis- Inflammation of the sinuses and nasal passages, upper respiratory tract infection, the most common three causative agents are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis MICROORGANISM  STREPTOCOCCUS PNEUMONIAE  Gram positive coccus  0.5 to 1.2 μm in diameter, oval or lancet shaped, and arranged in pairs and short chain  Older cells decolorize readily and appear gram-negative.  Alpha hemolytic on BAP  Catalase negative Microbiology: A Clinical Approach © Garland Science  Gram staioning S. pneumoniae Microbiology: A Clinical Approach © Garland Science PHYSIOLOGY AND STRUCTURE Virulent strains of S. pneumoniae are covered with a complex polysaccharide capsule. It is these polysaccharides that are used for the serologic classification of strains; currently, 90 serotypes are recognized. Purified capsular polysaccharides from the most commonly isolated serotypes are used in the pneumococcal vaccine.  Haemophilus influenzae Aerobic gram-negative bacteria Polysaccharide capsule Six different serotypes (a-f) of polysaccharide capsule 95% of invasive disease caused by type b Organism colonizes nasopharynx In some persons organism invades bloodstream and cause infection at distant site Antecedent upper respiratory tract infection may be a contributing factor Microbiology: A Clinical Approach © Garland Science  Haemophilus influenzae Gram staioning Haemophilus Haemophilus influenzae needs factors X and V Microbiology: A Clinical Approach © Garland Science Haemophilus influenzae type b Epidemiology Reservoir Human Asymptomatic carriers Transmission Respiratory droplets Temporal pattern Peaks in Sept-Dec and March-May Communicability Generally limited but higher in some circumstances Moraxella catarhalis  Gram negative diplococcus  Non motil  Aerob  Oxidase positive Pharyngitis  A variety of bacteria can cause infection in the pharynx.  A classic infection is strep throat.  Caused by Streptococcus pyogenes  Contains M proteins which inhibits phagocytosis  Produces pyrogenic toxins which cause the symptoms seen with pharyngitis  Group A streptococci can cause abscesses on the tonsils.  S. pyogenes can cause scarlet fever and toxic shock syndrome. Streptococcal Pharyngitis-reddened adenoids -side of the throat (URT Bacterial Diseases) Scarlet fever Caused by Group A streptococci Usually seen in children under age of 18 years Symptoms usually begin with appearance of a rash. Tiny bumps on the chest and abdomen Can spread over the entire body Appears redder in armpits and groin Rash lasts 2-5 days Streptococcus pyogenes Coccus Gram positive Catalase negative Chain arrangement Virulence Factors S. pyogenes Diphtheria Caused by the toxin produced by Corynebacterium diphtheriae A potent inhibitor of protein synthesis It is a localized infection. Presents as severe pharyngitis Can be accompanied by plaque-like pseudomembrane in the throat  …Diphtheria Corynebacterium diphtheriae © Visuals Unlimited Microbiology: A Clinical Approach © Garland Science Diphtheria: vaccination Vaccination against diphtheria- Infection is rare when vaccination is in place. Diphtheria still occurs frequently in some parts of the world, particularly where conditions do not permit vaccination. Toxin neutralization (exotoxin) is the most important. Must be done as quickly as possible Antitoxin can only neutralize free toxin. Pathogen elimination is also important. Corynebacterium diphtheriae is sensitive to many antibiotics DIPHTHERIA: Pathogenesis Corynebacterium diphtheriae is a small Gram-positive bacillus. Has V and L forms Forms are caused by a unique cell division process – snapping. Corynebacterium is poorly invasive. Effects of infection are due to the exotoxin. DIPHTHERIA: Pathogenesis  Local effects include epithelial cell necrosis and inflammation.  Pseudomembrane is composed of a mixture of fibrin, leukocytes, cell debris. ◦ Size varies from small and localized to extensive ◦ An extensive membrane can cover the trachea.  Incubation takes two to four days.  Disease usually presents as pharyngitis or tonsillitis with fever, sore throat, and malaise.  Pseudomembrane can develop on tonsils, uvula, soft palate, or pharyngeal walls. ◦ May extend downward toward larynx and trachea. VIRAL INFECTIONS OF THE UPPER RESPIRATORY TRACT Viral infections of the upper respiratory tract RHINOVIRUS INFECTION -There are several hundred serotypes of rhinovirus. Fewer than half have been characterized. 50% that have are all picornaviruses. Extremely small, non-enveloped, single-stranded RNA viruses Optimum temperature for picornavirus growth is 33˚C. The temperature in the nasopharynx Viral infections of the upper respiratory tract PARAINFLUENZA: There are four types of parainfluenza virus. All belong to the paramyxovirus group. Single-stranded enveloped RNA viruses Contain hemagglutinin and neuraminidase Transmission and pathology similar to influenza virus, but there are differences. Parainfluenza virus replicates in the cytoplasm. Influenza virus replicates in the nucleus. PARAINFLUENZA Parainfluenza is genetically more stable than influenza. Very little mutation Little antigenic drift No antigenic shift Parainfluenza is a serious problem in infants and small children. Only a transitory immunity to reinfection Infection becomes milder as the child ages. BACTERIAL INFECTIONS OF THE LOWER RESPIRATORY TRACT Bacterial infections of the lower respiratory tract 1. Bacterial pneumonia 2. Chlamydial pneumonia 3. Mycoplasma pneumonia 4. Tuberculosis 5. Pertussis 6. Inhalation anthrax 7. Legionella pneumonia (Legionnaire’s disease) BACTERIAL PNEUMONIA One of the most serious lower respiratory tract infections. Bacterial pnemonia can be divided into two types: Nosocomial Community-acquired Each type can be caused by a variety of organisms. BACTERIAL PNEUMONIA  Hospital acquired pneumonia (HAP)  Occurs approximately 48 hours after admission to hospital  Caused by Gram-negative bacteria (E. coli, K. pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii)  Particularly difficult to deal with if pathogen is resistant to antibiotics  Community-acquired pneumonia (CAP)  Usually presents as a lobar pneumonia  Accompanied by fever, chest pain, and production of purulent sputum Types of bacteria causing pneumonia Gram-positive bacteria: Streptococcus pneumoniae, often called "pneumococcus" , Staphylococcus aureus, with Streptococcus agalactiae. Gram-negative bacteria: Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Moraxella catarrhalis. CHLAMYDIAL PNEUMONIA Caused by Chlamydia pneumoniae: Found throughout the world Responsible for 10% of pneumonia cases- pharyngitis Lower-respiratory-tract infection Infection occurs throughout the year. Spread by person-to-person contact More infections in the elderly Can cause both community-acquired and nosocomial infections Similar to Mycoplasma pneumonia. Tetracycline or erythromycin MYCOPLASMA PNEUMONIA Mild form of pneumonia Accounts for about 10% of all pneumonias Referred to as walking pneumonia No need for hospitalization. Most common age for infections between 5 and 15 years. Causes approximately 30% of all teenage pneumonias. MYCOPLASMA PNEUMONIA  Caused by Mycoplasma pneumoniae ◦ Lacks a cell wall ◦ Acquired by droplet transmission ◦ Infectious dose fewer than 100 pathogens ◦ Found throughout the world, especially in temperate climates  Infection affects the trachea, bronchi, and bronchioles. ◦ May extend down to the alveoli Fever, headache, and malaise for 2 to 4 days ◦ Mild tracheobronchitis. ◦ Fever, cough, headache, and malaise. ◦ Sore throat. ◦ Otitis media ◦ Treatment : erythromycin or tetracycline TUBERCULOSIS An estimated 1.7 billion people are infected. 3 million die each year AIDS and HIV infection have had a significant role in the increase of tuberculosis. They increase the efficiency of the tuberculosis transmission cycle. Poverty and poor socioeconomic conditions are breeding grounds for tuberculosis. …TUBERCULOSIS  Drug resistance is becoming increasingly dangerous.  A major reason for resistance is noncompliance. ◦ Many patients stop taking the drugs early.  Early detection is vital.  Initial symptoms are similar to those seen in other respiratory infections – it is important to look for: ◦ Fever ◦ Fatigue ◦ Weight loss ◦ Chest pain ◦ Shortness of breath ◦ Congestion with coughing …TUBERCULOSIS Caused by Mycobacterium tuberculosis Rod-shaped bacillus Acid-fast stain Nonspore forming Produces mycolic acid Makes it difficult to Gram stain Protects the pathogen from antibiotic therapy and host defenses PERTUSSIS (WHOOPING COUGH) Spread by airborne droplets from patients in the early stages. Highly contagious Infects 80-100% of exposed susceptible individuals. Spreads rapidly in schools, hospitals, offices, and homes – just about anywhere. ….PERTUSSIS Caused by Bordetella pertussis Gram-negative coccobacillus Does not survive in the environment Reservoir is humans. Symptoms can be similar to those of a cold. Infected adults often spread the infection to schools and nurseries. …PERTUSSIS  Mortality is highest in infants and children under 1 year old.  Immunization against pertussis started in the 1940s.  Continues today as part of DTaP vaccination  Pertussis appears to be making a comeback.  Epidemics are occurring every 3-5 years.  Greatest numbers of infections are among 10-20 year-olds.  People who were not immunized  Shows a relationship between lack of vaccination and infection..PERTUSSIS: Pathogenesis  Bordetella pertussis has an affinity for ciliated bronchial epithelium.  After attaching, it produces a tracheal toxin.  Immobilizes and progressively destroys the ciliated cells.  Causes persistent coughing  Caused by the inability to move the mucus that builds up  Pertussis does not invade cells of the respiratory tract or deeper tissues.  Incubation period is 7 to 10 days...PERTUSSIS: Pathogenesis Infection has three stages: Persistent perfuse and mucoid rhinorrhea (runny nose) May have sneezing, malaise, and anorexia Most communicable during this stage Complication of pertussis can lead to superinfection with Streptococcus pneumonia. PERTUSSIS: Pathogenesis Most common complications of pertussis are: Superinfection with Streptococcus pneumonia. Convulsions. Subconjunctival and cerebral bleeding and anoxia. INHALATION ANTHRAX Produces a fulminate pneumonia Comes on suddenly with great severity Leads to respiratory failure and death Anthrax primarily a disease of herbivores Acquired from spores found in pastures If spores are inhaled, anthrax can occur in the respiratory tract...INHALATION ANTHRAX  Infection is infrequently seen in healthy individuals.  Usually presents as localized lesions where it occurs.  Has been recent interest in inhalation anthrax as a biological weapon  In October 2001, letters contaminated with powdered anthrax spores were mailed to various locations in the US.  Several deaths resulted...INHALATION ANTHRAX: Pathogenesis The causative agent is Bacillus anthracis. Gram-positive rod Spore-forming Spores germinate in human tissues. Antiphagocytic properties of the capsule aid its survival and growth in large numbers....INHALATION ANTHRAX Pathogenesis Pathogenesis results from the powerful exotoxin produced.  Symptoms of pulmonary anthrax are:  1-5 days of nonspecific malaise, mild fever, nonproductive cough.  Progressive respiratory distress and cyanosis.  Rapid and massive spread to the central nervous system and bloodstream is followed by death.  Antibiotic therapy can be successful.  B. anthracis is susceptible to penicillin.  Doxicycline and ciprofloxacin are alternative prophylactics. LEGIONELLA PNEUMONIA (LEGIONNAIRES’ DISEASE) Caused by Legionella pneumophila Gram-negative rod Cannot be stained or grown using normal techniques Transmitted to humans as a humidified aerosol;not person to person Legionella is ubiquitous in fresh water. Erythromycin is better than penicillin. VIRAL INFECTIONS OF THE LOWER RESPIRATORY TRACT 75-80% of all acute respiratory tract infections in the US are of viral origin. Everyone has 3 or 4 per year Incidence varies inversely with age. Greatest in young children VIRAL INFECTIONS OF THE LOWER RESPIRATORY TRACT  Majority of acute viral infections are in the lower respiratory tract and caused by: Influenza virus. Respiratory syncytial virus. Common characteristics of infection are: Short incubation period of 1 to 4 days. Transmission from person to person. Transmission can be direct or indirect. Direct – through droplets Indirect – through hand transfer of contaminated secretions INFLUENZA Influenza virus is an orthomyxovirus. Virions are surrounded by an envelope. Genome is single-stranded RNA Allows a high rate of mutation Three major serotypes of virus: A, B, and C. Differences are based on antigens associated with the nucleoprotein. INFLUENZA Influenza is a significant health concern. Human virus can combine with an avian virus to produce a highly pathogenic virus. Humans are the hosts for influenza. Aquatic birds are the reservoir. Epidemiology INFLUENZA Primary manifestation of infection is severe respiratory problems. Outbreaks have been described since the sixteenth century. Differ in severity nearly every year Occur more frequently in the winter Direct droplet transmission most common method of spreading. Pathogenesis INFLUENZA  Influenza virus prefers the respiratory epithelium.  Viremia is rare.  Virus multiplies in the ciliated cells of lower respiratory tract.  Results in functional and structural abnormalities  Cellular synthesis of nucleic acids and proteins is shut down.  Ciliated and mucus-producing epithelial cells are shed.  Substantial interference with clearance mechanisms  Localized inflammation …Pathogenesis Three bacteria are common causes of superinfection. Streptococcus pneumoniae Haemophilus influenzae Staphylococcus aureus Treatment INFLUENZA  Two basic approaches  Symptomatic care  Anticipation of potential complications  The best treatments are:  Rest and fluid intake  Conservative use of analgesics for myalgia and headache  Cough suppressants.  Amantidine and rimantadine are useful only if the infection is diagnosed within 12-24 hours.  Summary Viral and bacteria as agents of Respiratory Tract Infections TERIMAKASIH Microbiology: A Clinical Approach © Garland Science