Healthcare Associated Pneumonia & Emerging Viral Diseases PDF

Faculty of Medicine  Faculty of Medicine Modern University for Technology and Information  Respiratory System Module Healthcare associated Pneumonia & emerging viral diseases Medical Microbiology & Immunology Department ...

Faculty of Medicine  Faculty of Medicine Modern University for Technology and Information  Respiratory System Module Healthcare associated Pneumonia & emerging viral diseases Medical Microbiology & Immunology Department  ILOs By the end of this lecture, Students will be able to: Define healthcare associated pneumonia. List causative agents of healthcare associated pneumonia and VAP. Outline healthcare associated pneumonia. Outline management of healthcare associated pneumonia. Outline emerging viral diseases. Explain management of emerging viral diseases.  Pneumonia Pneumonia is an inflammation of the lung affecting the alveoli. Pneumonia classified according to Presenting symptoms & Source of infection causative organism Community acquired Hospital-acquired Typical Atypical (acquired outside of the (48 hrs. or more after pneumonia pneumonia hospital) admission to hospital) 11/14/2024 Medical microbiology and immunology department - MTI  Healthcare associated pneumonia Pneumonia that occurs 48 hours or more after admission to the hospital and was not present nor incubated at the time of admission. 11/14/2024 Medical microbiology and immunology department - MTI  Causative agents of Healthcare associated pneumonia Bacteria Viruses Fungi Gram-negative bacilli: Influenza, parainfluenza, Aspergillus fumigatus, E. coli adenovirus, and respiratory Candida species may cause klebsiella pneumoniae, syncytial virus. nosocomial pneumonia in Pseudomonas aeruginosa  RSV outbreaks of bronchiolitis and organ transplant or immunocompromised, Acinetobacter species. pneumonia are more neutropenic patients. Gram-positive cocci: common in children’s But is uncommon in especially S. aureus. wards. immunocompetent patients.  Influenza A is the most common viral cause in adult patients. 11/14/2024  Sources of infection Environment Devices Air Water (respiratory Equipment devices and Fomites equipment) Other patients Staff The severity of the patient’s underlying disease, prior surgery, exposure to antibiotics, other medications 11/14/2024 Medical microbiology and immunology department - MTI  Routes of Pathogens entry into the lower respiratory tract causing pneumonia Aspiration of oropharyngeal pathogens. Inhalation of pathogens from contaminated aerosols. Direct inoculation, Hematogenous spread from a distant body site (less common). 11/14/2024 Medical microbiology and immunology department - MTI  Clinical Manifestations & Complications Clinical Manifestations: High fever (may be the only presentation). Increased respiratory secretions. Increased oxygen requirements. Complications: Pleural effusion. Pleural empyema. 11/14/2024 Medical microbiology and immunology department - MTI  Diagnosis The gold standard for diagnosis is an infiltrate on a plain chest radiograph. Clinical data may be helpful. Sputum analysis for Gram stain and culture & blood cultures may be helpful in the hospitalized patient. PCR tests for various respiratory pathogens e.g. Influenza virus, RSV are useful. Diagnosis= Radiologic + Clinical +Microbiological. 11/14/2024 Medical microbiology and immunology department- MTI  Treatment Patients with suspected hospital-acquired pneumonia may be given broad spectrum agents e.g. carbapenem (ertapenem) depending on the local epidemiology (Many hospital acquired infections are multidrug resistant). Prompt initiation of antibiotics is important because morbidity and mortality increase after a delay of > 8 hours. Drainage of empyema or infected pleural fluid. 11/14/2024 Medical microbiology and immunology department - MTI  Pneumonia that occurs 48–72 hours after endotracheal intubation. 11/14/2024 Medical microbiology and immunology department - MTI  In ICU patients, 90% of hospital acquired pneumonia occur during mechanical ventilation.  The artificial airway increases the opportunity for aspiration and colonization.  The incidence of VAP increases with duration of ventilation. 11/14/2024 Medical microbiology and immunology department - MTI  Organisms Causing VAP Early onset VAP Late onset VAP  >5 days since intubation.  Within 4 days of intubation.  Patient mortality and morbidity.  Usually carry a better prognosis.  More likely to be caused by  More likely to be caused by antibiotic multidrug-resistant(MDR) bacteria. sensitive bacteria. Pseudomonas aeruginosa Streptococcus pneumoniae. Staphylococcus aureus (MRSA). Acinetobacter species.  Haemophilus influenzae. E. Coli. Staphylococcus aureus. Klebsiella species. 11/14/2024 Medical microbiology and immunology department - MTI  Emerging viral diseases Viral diseases emerge following one of three general patterns: Recognition of a new agent. Abrupt increase in illnesses caused by an endemic agent.  Invasion of a new host population. 11/14/2024 Medical microbiology and immunology department - MTI  Factors contribute to disease emergence Environmental changes (deforestation, flood or drought). Human behavior (sexual behavior, drug use, outdoor recreation). Socioeconomic and demographic phenomena (population growth, migration). Travel and commerce (international air travel). Food production (globalization of food supplies, changes in methods of food processing and packaging). 11/14/2024 Medical microbiology and immunology department - MTI  Factors contribute to disease emergence Health care (new medical devices, blood transfusions, organ and tissue transplantation, drugs causing immunosuppression). Microbial adaptation: new viral strains arising through mutation, reassortment resulting in changes in transmissibility, virulence, or development of drug resistance). Public health measures (inadequate sanitation and vector control measures, limited prevention programs). Examples of emerging viral agents: CoV- SARS. MERS-CoV. SARS-CoV-2. Hantavirus. 11/14/2024 Ebola virus. Medical microbiology and immunology department - MTI  Coronaviruses Coronaviruses are second to rhinoviruses as an important cause of the common cold. New CoVs have emerged: CoV- SARS which causes the severe acute respiratory syndrome (SARS). MERS-CoV which causes the middle East respiratory syndrome (MERS). SARS-CoV-2 which causes the Coronavirus disease 2019 (COVID-19). 11/14/2024 Medical microbiology and immunology department - MTI  Structure of Corona virus  Non-segmented, single-stranded, positive-sense RNA genome with a helical nucleocapsid. The envelope contains prominent club- shaped spikes that gives the appearance a corona. 11/14/2024 Medical microbiology and immunology department - MTI  CoV-SARS  SARS originated in China in 2002 and spread rapidly to other countries.  Bats are the natural reservoir.  The civet cat serving as an intermediate host.  Human-to-human transmission occurs. 11/14/2024 Medical microbiology and immunology department - MTI  MERS-CoV  In 2012, MERS-CoV caused an outbreak of serious, often fatal pneumonia in Saudi Arabia and other countries in the region.  Bats are the reservoir.  Humans are infected through close contact with infected camels.  Human-to-human transmission is low. 11/14/2024 Medical microbiology and immunology department - MTI  SARS-CoV-2  Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2.  It was first identified in December 2019 in Wuhan, China. Most patients were epidemiologically linked to animal market in Wuhan.  In March 2020, The World Health Organization (WHO) has declared the COVID-19 as a global pandemic.  SARS-CoV-2 Originated in Bats. 11/14/2024 Medical microbiology and immunology department - MTI  Pathogenesis Transmitted by respiratory droplets. Infection is limited to the mucosal cells of the respiratory tract. 50% of infections are asymptomatic. Pneumonia caused by CoV-SARS is characterized by diffuse edema resulting in hypoxia. The binding of the virus to angiotensin- converting enzyme-2 (ACE-2) on the surface of respiratory tract epithelium may contribute to the dysregulation of fluid balance that causes the edema in the alveolar space. MERS-CoV binds to CD-26 on the respiratory mucosa. 11/14/2024 Medical microbiology and immunology department - MTI  Clinical manifestations of corona viruses The common cold caused by coronavirus: runny nose, scratchy sore throat and low-grade fever. Coronaviruses also cause bronchitis. The incubation period for CoV-SARS & MERS-CoV ranges from 2 to 10 days. SARS is a severe atypical pneumonia characterized by a fever, nonproductive cough, dyspnea, and hypoxia. Chills, rigors, malaise, and headache. Some patients progress to acute respiratory distress syndrome. Chest X-ray reveals interstitial “ground-glass” infiltrates, Leukopenia and thrombocytopenia are seen. The clinical findings of MERS are similar to those of SARS. 11/14/2024 Medical microbiology and immunology department - MTI  Clinical manifestations of corona viruses The incubation period for SARS-CoV-2 ranges from 2 to 14 days. COVID-19 characterized by respiratory symptoms (cough, shortness of breath, breathing difficulties, + fever). In severe cases: infection can cause pneumonia, severe acute respiratory syndrome. 11/14/2024 Medical microbiology and immunology department - MTI 11/14/2024 Medical microbiology and immunology department - MTI  Laboratory Diagnosis PCR assay to detect viral RNA in respiratory tract specimens. Antibody-based tests to detect a rise in antibody titer. 11/14/2024 Medical microbiology and immunology department - MTI  Prevention Important Vaccines against COVID19: Vaccine Immunogen Preparation type RNA Messenger RNA for Enclosed in lipid spike protein nanoparticles. (Pfizer and Moderna) Vector Human adenovirus Adenovirus is engineered to (serotype 26) be nonreplicating. (Johnson containing DNA spike &Johnson) protein Vector Chimpanzee Chimpanzee adenovirus is adenovirus containing nonreplicating and DNA encoding spike nonpathogenic in humans protein (AstraZenica) 11/14/2024 Medical microbiology and immunology department - MTI  Prevention 2- Monoclonal antibodies can be used for prevention as well as treatment. They can be used either preexposure or postexposure. 3-Public health and hygiene measures to interrupt transmission: Wearing a mask and physical distancing frequent hand washing, practicing cough and sneeze etiquette, Personal protective equipment (PPE) for medical personnel is essential to interrupt transmission in hospitals. 4-The public health measures of isolation and quarantine are also very important. 5-Contact tracing to identify those who have been exposed is important to interrupt the chain of transmission. 11/14/2024 Medical microbiology and immunology department - MTI  Hantavirus Hantaviruses are members of the bunyavirus family. Enveloped viruses with single-stranded, segmented, negative sense RNA. Rodent-borne viruses: transmitted from rodents directly. Cause hemorrhagic fever with renal syndrome (Korean hemorrhagic fever). 11/14/2024 Medical microbiology and immunology department - MTI  Hantavirus Pulmonary Syndrome A new disease, Hantavirus Pulmonary Syndrome has emerged. Reservoir: Deer mice. Acquired by inhalation of aerosols of the rodent’s urine and feces. No human to human transmission. The disease characterized by influenza like symptoms followed rapidly by acute respiratory failure. The mortality rate is very high. Prevention depends on rodent control& avoidance of contact with rodents and rodent droppings. 11/14/2024 Medical microbiology and immunology department - MTI Which of the following is the target receptor of MERS-CoV in the respiratory tract? a) Angiotensin-converting enzyme-2. b) CD-26. c) Neuraminic acid. d) Sialic acid. Answer: B 11/14/2024 Medical microbiology and immunology department - MTI Which of the following best describes the mode of transmission of hantavirus? a)Bite of ticks. b)Ingestion of contaminated meat. c)Inhalation of aerosols of rodent’s feces and urine. d)Direct contact with infected animal tissues. Answer: C 11/14/2024 Medical microbiology and immunology department - MTI  REFERENCES -Review of Medical Microbiology and Immunology (2022) Warren L, 17th edition by McGraw- Hill Education. -Microbiology: an introduction (2013) Gerard J. Tortora, Berdell R. Funke, Christine L. Case, 11th Edition, Pearson Education -Jawetz, Melnick, & Adelberg’s Medical Microbiology (2019) Riedel S, Morse SA, Mietzner TA, Miller S, 28th edition by McGraw- Hill Education.  SCAN ME Than k You