Microbial Disease of the Respiratory System PDF

MICROBIAL DISEASE OF THE RESPIRATORY SYSTEM Our Lady of Fatima University – College of Pharmacy  Unit Outcomes 1. Describe how microorganisms are prevented from entering the respiratory system. 2. Characterize the normal microbiota of the upper and lowe...

MICROBIAL DISEASE OF THE RESPIRATORY SYSTEM Our Lady of Fatima University – College of Pharmacy  Unit Outcomes 1. Describe how microorganisms are prevented from entering the respiratory system. 2. Characterize the normal microbiota of the upper and lower respiratory systems. 3. Differentiate pharyngitis, laryngitis, tonsillitis, sinusitis, and epiglottitis. 4. List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for streptococcal pharyngitis, scarlet fever, diphtheria, cutaneous diphtheria, and otitis media.  Unit Outcomes 5. List the causative agents and treatments for the common cold. 6. List the causative agent, symptoms, prevention, preferred treatment, and laboratory identification tests for pertussis and tuberculosis. 7. Compare and contrast the seven bacterial pneumonias discussed in this chapter. 8. List the etiology, method of transmission, and symptoms of melioidosis.  Unit Outcomes 9. List the causative agent, symptoms, prevention, and preferred treatment for viral pneumonia, RSV, and influenza. 10. List the causative agent, mode of transmission, preferred treatment, and laboratory identification tests for four fungal diseases of the respiratory system.  Unit Outline 1. Structure and Function of the Respiratory System 2. Normal Microbiota of the Respiratory System 3. Microbial Disease of the Upper Respiratory System a. Bacterial Infections b. Viral Infections 4. Microbial Disease of the Lower Respiratory System a. Bacterial Infections b. Viral Infections c. Fungal Infections 5. COVID-19 RESPIRATORY SYSTEM  Structure and Function of the Respiratory System Infections of the upper respiratory system are the most common type of infection. Pathogens that enter the respiratory system can infect other parts of the body.  Structure and Function of the Respiratory System The Upper Respiratory System The upper respiratory system consists of the nose, pharynx, and associated structures, such as the middle ear and auditory tubes.  Structure and Function of the Respiratory System Coarse hairs in the nose filter large particles from air entering the respiratory tract. The ciliated mucous membranes of the nose and throat trap airborne particles and remove them from the body.  Structure and Function of the Respiratory System Lymphoid tissue, tonsils, and adenoids provide immunity to certain infections.  Structure and Function of the Respiratory System The Lower Respiratory System The lower respiratory system consists of the larynx, trachea, bronchial tubes, and alveoli.  Structure and Function of the Respiratory System The ciliary escalator of the lower respiratory system helps prevent microorganisms from reaching the lungs. Microbes in the lungs can be phagocytized by alveolar macrophages. Respiratory mucus contains IgA antibodies.  Normal Microbiota of the Respiratory System The normal microbiota of the nasal cavity and throat can include pathogenic microorganisms. Microbial Disease of the UPPER RESPIRATORY SYSTEM  Microbial Diseases of the Upper Respiratory System Specific areas of the upper respiratory system can become infected to produce pharyngitis, laryngitis, tonsillitis, sinusitis, and epiglottitis. https://www.cdc.gov/antibiotic-use/community/for-patients/common-illnesses/sinus-infection.html  https://upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Pharyngitis.j pg/300px-Pharyngitis.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Pos_s trep.JPG/300px-Pos_strep.JPG https://coreem.net/core/epiglottitis/ Microbial Diseases of the Upper Respiratory System These infections may be caused by several bacteria and viruses, often in combination. Most respiratory tract infections are self- limiting. Haemophilus influenzae type b can cause epiglottitis.  Bacterial Diseases of the Upper Respiratory System  Streptococcal Pharyngitis Also known as strep throat This infection is caused by group A beta- hemolytic streptococci, the group that consists of Streptococcus pyogenes.  Streptococcal Pharyngitis Symptoms of this infection are inflammation of the mucous membrane and fever; tonsillitis and otitis media may also occur. Rapid diagnosis is made by enzyme immunoassays. Immunity to streptococcal infections is type- specific.  Scarlet Fever Strep throat, caused by an erythrogenic toxin- producing S. pyogenes, results in scarlet fever. S. pyogenes produces erythrogenic toxin when lysogenized by a phage. Symptoms include a red rash, high fever, and a red, enlarged tongue. https://www.gponline.com/infectious-diseases-scarlet- fever/infections-and-infestations/nfeictions-and- infestations/article/1324924 https://www.nhs.uk/conditions/scarlet-fever/  Diphtheria Diphtheria Caused by exotoxin-producing Corynebacterium diphtheriae. Exotoxin is produced when the bacteria are lysogenized by a phage.  Diphtheria A membrane, containing fibrin and dead human and bacterial cells, forms in the throat and can block the passage of air. https://upload.wikimedia.org/wikipedia/commons/thumb/4/47/Dirty_white_pseudomembrane_classically_seen_in_diphtheria_2013-07-06_11- 07.jpg/290px-Dirty_white_pseudomembrane_classically_seen_in_diphtheria_2013-07-06_11-07.jpg  Diphtheria The exotoxin inhibits protein synthesis, and heart, kidney, or nerve damage may result. Laboratory diagnosis is based on isolation of the bacteria and the appearance of growth on differential media. Routine immunization in the United States includes diphtheria toxoid in the DTaP vaccine.  Diphtheria Slow-healing skin ulcerations are characteristic of cutaneous diphtheria. There is minimal dissemination of the exotoxin in the bloodstream.  Otitis Media Earache, or otitis media, can occur as a complication of nose and throat infections. Pus accumulation causes pressure on the eardrum. Bacterial causes include Streptococcus pneumoniae, non- encapsulated Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pyogenes.  Viral Diseases of the Upper Respiratory System  The Common Cold Any one of approximately 200 different viruses, including rhinoviruses, coronaviruses, and EV-D68, can cause the common cold. We tend to accumulate immunities against these viruses during our lifetime.  The Common Cold The symptoms include sneezing, excessive nasal secretion, and congestion. The incidence of colds increases during cold weather, possibly because of increased interpersonal indoor contact or physiological changes. Microbial Disease of the LOWER RESPIRATORY SYSTEM Microbial Diseases of the Lower Respiratory System Many of the same microorganisms that infect the upper respiratory system also infect the lower respiratory system. Diseases of the lower respiratory system include bronchitis and pneumonia. https://www.medicalnewstoday.com/articles/327431  Bacterial Diseases of the Lower Respiratory System  Pertussis Also known as whooping cough. Pertussis is caused by Bordetella pertussis. The initial stage of pertussis resembles a cold and is called the catarrhal stage. The accumulation of mucus in the trachea and bronchi causes deep coughs characteristic of the paroxysmal (second) stage.  Pertussis The convalescence (third) stage can last for months. Regular immunization for children has decreased the incidence of pertussis.  Tuberculosis Tuberculosis is caused by Mycobacterium tuberculosis. Mycobacterium bovis causes bovine tuberculosis and can be transmitted to humans by unpasteurized milk. M. avium-intracellulare complex infects patients in the late stages of HIV infection.  Tuberculosis Tuberculosis An infectious disease caused by the bacterium M. tuberculosis, a thin rod and an obligate aerobe. https://publichealth.yale.edu/research_practice/departments/emd/diseases/tuberculosis/  Tuberculosis The rods grow slowly (20-hour or longer generation time), sometimes form filaments, and tend to grow in clumps.  Tuberculosis Mycobacteria stained with carbol fuchsin dye cannot be decolorized with acid-alcohol and are therefore classified as acid-fast. This is due to their high lipid cell wall containing mycolic acid. It is responsible for the resilient characteristic of the bacterium, i.e., resistant to drying, antiseptics and disinfectants.  Tuberculosis M. tuberculosis may be ingested by alveolar macrophages; if not killed, the bacteria reproduce in the macrophages.  Tuberculosis Lesions formed by M. tuberculosis are called tubercles; macrophages and bacteria form the caseous lesion that might calcify and appear in an X-ray image as a Ghon’s complex.  Tuberculosis Liquefaction of the caseous lesion results in a tuberculous cavity in which M. tuberculosis can grow.  Tuberculosis Clinical Disease a. Primary infection involves the mid or lower lung field, and the focus is usually single. b. Active tuberculosis may develop as a progression of primary infection or as a reactivation of a quiescent infection.  Tuberculosis c. Miliary (disseminated) tuberculosis involves new foci of infection which can develop when a caseous lesion ruptures and releases bacteria into blood or lymph vessels.  Tuberculosis Diagnosis A positive tuberculin skin test can indicate either an active case of TB, prior infection, or vaccination and immunity to the disease. Active infections can be diagnosed by detection of IFN-γ or rapid PCR test for M. tuberculosis. https://www.theurgentcare.com/tb-skin-tests/ https://www.cdc.gov/tb/topic/testing/tbtesttypes.htm  Tuberculosis Treatment Chemotherapy usually involves three or four drugs taken for at least 6 months; multidrug- resistant M. tuberculosis is becoming prevalent. BCG vaccine for tuberculosis consists of a live, avirulent culture of M. bovis.  Bacterial Pneumonias Pneumonia An infection that inflames your lungs' air sacs (alveoli). The alveoli may fill up with fluid or pus, causing symptoms such as a cough, fever, chills and trouble breathing. Pneumonia, caused by bacteria. Figure A shows pneumonia affecting part of the left lung. Figure B shows healthy alveoli (air sacs). Figure C shows alveoli filled with mucus. https://www.nhlbi.nih.gov/health-topics/pneumonia  Bacterial Pneumonias Typical pneumonia (two-thirds of cases) is caused by pneumococci. Atypical pneumonias are caused by other microorganisms. Pneumococcal pneumonia Caused by encapsulated Streptococcus pneumoniae. S. pneumoniae is a gram-positive, ovoid bacterium that usually appears in pair.  Bacterial Pneumonias Symptoms Pneumococcal pneumonia involves both the bronchi and the alveoli. Symptoms include high fever, breathing difficulty, and chest pain. The sputum is often rust colored from blood coughed up from the lungs.  Bacterial Pneumonias Diagnosis Optochin test Bile solubility test Latex indirect agglutination test Treatment Antibiotic Vaccine (conjugated pneumococcal, pneumococcal polysaccharide)  Bacterial Pneumonias Children under 5 and adults over 65 are most susceptible to Haemophilus influenzae pneumonia. H. influenzae is a gram-negative coccobacillus. Treatment 3rd generation cephalosphorins Hib vaccine  Bacterial Pneumonias Mycoplasma pneumoniae causes mycoplasmal pneumonia; it is an endemic disease. M. pneumoniae lacks cell wall. The symptoms, which persist for 3 weeks or longer, are low-grade fever, cough, and headache. Other terms for the disease are primary atypical and walking pneumonia.  Bacterial Pneumonias Legionellosis Also known as Legionnaire’s disease, is caused by the aerobic gram-negative rod Legionella pneumophila. Unknown until an outbreak in 1976 during American Legion Convention in Philadelphia. Characterized by a high fever of 40.5°C, cough, and general symptoms of pneumonia.  Bacterial Pneumonias L. pneumophila is also responsible for Pontiac fever, which is essentially another form of legionellosis. Its symptoms include fever, muscular aches, and usually a cough. The condition is mild and self-limiting. During outbreaks of legionellosis, both forms may occur.  Bacterial Pneumonias Diagnosis Culture on Charcoal-Yeast extract medium Serological test Treatment Azithromycin Macrolide antibiotics  Bacterial Pneumonias Chlamydophila psittaci, the bacterium that causes psittacosis (ornithosis), is transmitted by contact with contaminated droppings and exudates of fowl. C. psittaci, is a gram-negative, obligate intracellular bacterium.  Bacterial Pneumonias Chlamydophila pneumoniae causes pneumonia; it is transmitted from person to person.  Bacterial Pneumonias Q fever Caused by the obligate intracellular parasitic bacteria Coxiella burnetii. This bacteria naturally infects some animals, such as goats, sheep, and cattle. People can get infected by breathing dust contaminated with secretions from these animals. Bacterial Pneumonia  Melioidosis Melioidosis Infection caused by Burkholderia pseudomallei Transmitted by inhalation, ingestion, or through puncture wounds Symptoms include pneumonia, sepsis, and encephalitis.  Viral Diseases of the Lower Respiratory System  Viral Pneumonia Several viruses can cause pneumonia as a complication of infections such as influenza. The etiologies are not usually identified in a clinical laboratory because of the difficulty in isolating and identifying viruses.  Respiratory Syncytial Virus Respiratory Syncytial Virus (RSV) A common respiratory virus that usually causes mild, cold-like symptoms. The most common cause of bronchiolitis and pneumonia in infants.  Influenza Influenza (Flu) Caused by Influenzavirus and is characterized by chills, fever, headache, and general muscular aches. Hemagglutinin (HA) and neuraminidase (NA) spikes project from the outer lipid bilayer of the virus. https://micro.magnet.fsu.edu/cells/viruses/influenzavirus.html  Influenza Viral strains are identified by antigenic differences in their protein coats (A, B, and C); influenza A is further subdivided by differences in the HA and NA spikes. Antigenic shifts and antigenic drift enable the virus to evade natural immunity.  Influenza Multivalent vaccines are available. Zanamivir and oseltamivir are effective drugs against influenza A virus.  Fungal Diseases of the Lower Respiratory System  Fungal Diseases of the Lower Respiratory System Fungal spores are easily inhaled; they may germinate in the lower respiratory tract. https://www.technologynetworks.com/diagnostics/news/marker-indicates-those-more-at-risk-from-lethal-fungal-spores-309768  Fungal Diseases of the Lower Respiratory System The incidence of fungal diseases has been increasing in recent years. The mycoses in the following sections can be treated with itraconazole.  Histoplasmosis Histoplasmosis Histoplasma capsulatum causes a subclinical respiratory infection that only occasionally progresses to a severe, generalized disease. May be associated with a chronic inflammatory process known as fibrosing mediastinitis.  Histoplasmosis The disease is acquired by inhaling airborne conidia. Isolating or identifying the fungus in tissue samples is necessary for diagnosis.  Coccidioidomycosis Coccidioidomycosis Results from inhaling the airborne arthroconidia of Coccidioides immitis. Most cases of are clinically occult or mild infections. But some patients have progressive pulmonary infection and may suffer dissemination to the brain, bone, and other sites.  Pneumocystis Pneumonia Pneumocystis pneumonia Pneumocystis jirovecii is found in healthy human lungs. However, it causes disease in AIDS patients and other immunosuppressed patients.  Blastomycosis Blastomycosis Also known as North American Blastomycosis Blastomyces dermatitidis is the causative agent of blastomycosis The infection begins in the lungs and can spread to cause extensive abscesses  Other Fungi Involved in Respiratory Disease Opportunistic fungi can cause respiratory disease in immunosuppressed hosts, especially when large numbers of spores are inhaled. Among these fungi are Aspergillus, Rhizopus, and Mucor.  COVID-19 SARS-CoV-2 Infection  COVID-19 Coronavirus Disease 2019 Defined as illness caused by SARS-CoV-2 (formerly called 2019-nCoV) https://emedicine.medscape.com/article/2500114-overview  COVID-19 Timeline First identified amid an outbreak of respiratory illness cases in Wuhan City, Hubei Province, China (Dec 31, 2019). Global health emergency (Jan 30, 2020) Global pandemic (March 11, 2020)  COVID-19 Patient 1: First confirmed COVID-19 case in the Philippines (January 30, 2020). Patient 2: Second confirmed case and first COVID-19 deaths outside of China (February 1, 2020). Edrada, E.M., Lopez, E.B., Villarama, J.B. et al. First COVID-19 infections in the Philippines: a case report. Trop Med Health 48, 21 (2020). https://doi.org/10.1186/s41182-020-00203-0  COVID-19 President Rodrigo Duterte’s declaration placing Metro Manila (March 15, 2020) under community quarantine and the rest of Luzon two days later (March 17, 2020). In Philippines, from 3 January 2020 to 4:14pm CET, 29 December 2021, there have been 2,839,111 confirmed cases of COVID-19 with 51,213 deaths, reported to WHO. As of 15 December 2021, a total of 100,019,137 vaccine doses have been administered.  COVID-19 Comorbidities DM Significant association Heart conditions with risk of severe Immunocompromised state from solid organ COVID-19: transplant CA Obesity Cerebrovascular Pregnancy disease Smoking, current or CKD former COPD  COVID-19 Signs and Symptoms Headache May develop 2 days – New loss of taste or smell 2 weeks after exposure Sore throat Fever or chills Congestion or runny Cough nose Shortness of breath or Nausea or vomiting difficulty breathing Diarrhea Fatigue Muscle or body aches  COVID-19 Diagnosis RT–PCR is a variation of PCR, or polymerase chain reaction. The two techniques use the same process except that RT– PCR has an added step of reverse transcription of RNA to DNA, or RT, to allow for amplification. https://www.iaea.org/newscenter/news/how-is-the-covid-19-virus-detected-using-real-time-rt- pcrhttps://www.sigmaaldrich.com/PH/en/applications/genomics/pcr  COVID-19 Management Vaccination Monoclonal-directed antibodies Convalescent plasma Remdesivir – viral RNA polymerase inhibitor Baricitinib – a Janus kinase inhibitor Tocilizumab – an interleukin-6 inhibitor  END OF DISCUSSION  References Background photo by Polina Tankilevitch from Pexels Tortora, G.J., Funke, B.R., & Case, C.L. (2019). Microbiology: an introduction 13th edition. Boston, MA: Pearson Parker, N., Schneegurt, M., Tu, A. -H. T., Lister, P., & Forster, B.M. (2016). Microbiology. Houston, Texas: OpenStax. https://openstax.org/books/ microbiology/pages/22-introduction Centers for Disease Control and Prevention. (2018, June 26). Respiratory syncytial virus (RSV). Retrieved December 16, 2020, from https://www.cdc.gov/rsv/ Centers for Disease Control and Prevention. (2019, January 15). Q fever. Retrieved December 16, 2020, from https://www.cdc.gov/qfever/index.html  References Edrada, E.M., Lopez, E.B., Villarama, J.B. et al. First COVID-19 infections in the Philippines: a case report. Trop Med Health 48, 21 (2020). https://doi.org/10.1186/s41182-020-00203-0 Cennimo, D., Bronze, M., Boyd, D., Wolf, S., & Miller, M. (2021). Coronavirus Disease 2019 (COVID-19): Practice Essentials, Background, Route of Transmission. Retrieved 3 January 2022, from https://emedicine.medscape.com/article/2500114-overview