Microbiology Lab

Microbiology Lab

Respiratory tract infection Done by : Yasmin El Helu Rana Abu Zuhri Asmaa Abu Shamla

Fungal infection of the respiratory tract

Aspergillosis Is an allergic reaction, invasive infection or growth caused by Aspergillusfumigatus. Inhaling of certain species of this fungi’s mold spores can lead to dire consequences, particularly by those with weak immune systems.

Aspergillosis takes on different forms:- • Allergic bronchopulmonaryaspergillosis allergic reaction to aspergillus, developing in those with pre-existing lung problems, such as asthma or cystic fibrosis.

Invasive pulmonary aspergillosis The most severe form of the disease by aspergillus mold spores. Almost exclusively affecting those with weakened immune systems, this infection spreads rapidly. It comes with a high risk of invading and damaging tissue throughout your body, especially your lungs , brain , heart and kidneys.

Aspergilloma • Is a fungus ball, occurring in those who had a previous lung disease. • Lungs that have air space damage caused by emphysema, tuberculosis, histoplasmosis, cystic fibrosis, sarcoidosis, lung cancer or other lung diseases develop pulmonary aspergilloma.

Histoplasmosis • Is an infectious disease caused by inhaling the spores of a fungus called Histoplasmacapsulatum. • Histoplasmosis is not contagious. • Primarily affects a person's lungs, and its symptoms vary greatly. The vast majority of infected people are asymptomatic , or can appear as a mild, flu-like respiratory illness . • People with weakened immune systems are at the greatest risk for developing severe and disseminated histoplasmosis.

Fungal Sinusitis Fungi involved in sinusitis include: • Aspergillus is the most common cause of all forms of fungal sinusitis. • Other fungi include, Alternaria, Cryptococcus, Candida, Sporothrix,, andMucormycosis.

Thrush Is an oral infection with the fungus Candida albicans, which causes yellow, raised sores in the mouth, sometimes extending to the throat (cause of sore throat).

Bacterial infection of the respiratory tract

Respiratory tract infection caused by Bacteria:- 1-Upper respiratory tract infections. 2- Otitis media 3-Lower respiratory tract infections. 4-Tuberculosis (TB).

The upper respiratory tract: includes the sinuses, nasal passages, pharynx, and larynx. • An upper respiratory tract infection : is an infectious process of any of the components of the upper airway.

Upper respiratory tract infection (URI): - • Represents the most common acute illness evaluated in the outpatient setting. • Viruses account for most URIs. • Bacteria account for up to 25 percent of upper respiratory tract infections. • Bacterial primary infection or superinfection may require targeted therapy. • Specific manifestations of URIs:- Rhinitis, pharyngitis, sinusitis, epiglottitis, laryngitis, and tracheitis .

Pharyngitis:- Is defined as an infection or irritation of the pharynx and/or tonsils. • The etiology is usually infectious:- 1- Viral origin, which is the most common cause. These cases are benign and self-limiting for the most part. 2- Bacterial origin, which is self-limiting, but are concerning because of suppurative and nonsuppurative complications. 3-Fungal origin • Non-infectious allergy, trauma(mechanical, chemical or thermal irritation), toxins, and neoplasia.

Bacteria causes pharyngitis:- 1-Streptococcal pharyngitis • Caused by group A beta hemolytic streptococcus (GAS)-(Streptococcus pyogenes). • The most significant bacterial agent causing pharyngitis in both adults and children. • Symptoms include fever ,sore throat,, and enlarged lymph node. • It is the cause of 37% of sore throats among children. • A definitive diagnosis is made based on the results of a throat culture

A culture positive case of streptococcal pharyngitis with typical tonsillar exudate in a 16 year old.

Note the redness and edema of the oropharynx, the petechiae, or small red spots, on the soft palate. This is an uncommon but highly specific finding in streptococcal pharyngitis.

2-Fusobacterium necrophorum • Are normal inhabitants of the oropharyngeal flora. • responsible for 10% of all acute sore throats, 21% of all recurring sore throats, and 23% of peritonsillar abscesses • In 1 out of 400 untreated cases, Lemierre's syndrome occurs- Known as (human necrobacillosis)- It’s a form of thrombophlebitis.

Fusobacteriumnecrophorumbacteria cultured in a thioglycollate medium for 48 hours.F. necrophorum is a nonmotile, gram-negative anaerobe that normally inhabitants the pharynx, gastrointestinal tract, and female genital tract.

3- Diphtheria life threatening upper respiratory infection caused by Corynebacteriumdiphtheriaewhich has been largely eradicated in developed nations since the introduction of childhood vaccination programs, but is still reported in the Third Worldand increasingly in some areas in Eastern Europe. • Clinical criteria • Upper respiratory tract illness with sore throat • Low-grade fever • An adherent pseudomembrane of the tonsil(s), pharynx, and/or nose.

Epiglottitis:- • Inflammation of the epiglottis , swelling of this structure can interfere with breathing and constitutes a medical emergency . • The infection can cause the epiglottis to either obstruct or completely close off the trachea. • Caused by:- Haemophilus influenzae type B, although some cases are attributable to Streptococcus pneumoniae , Streptococcus agalactiae, Staphylococcus aureus, and Streptococcus pyogenes

Acute H influenzae type b epiglottitis with striking erythema and swelling of the epiglottis.

` Tracheitis:- Although the trachea is usually considered part of the lower respiratory tract, in ICD-10 tracheitis is classified under "Acute upper respiratory infections". Bacterial tracheitis • A bacterial infection of the trachea and is capable of producing airway obstruction. • One of the most common causes is Staphylococcus aureusand often follows a recent viral upper respiratory infection. • It is the most serious in young children, possibly because of the relatively small size of the trachea that gets easily blocked by swelling.

Sinusitis • The bacteria most commonly implicated in sinusitis include: • Streptococcus pneumoniae. This bacterium is found in up to 45% of adults and children with sinusitis. • H. influenzae(a common bacterium associated with many upper respiratory infections). This bacterium causes about 25% of sinusitis cases in children. • Moraxellacatarrhalis. Over 75% of all children harbor this bacterium, which causes about 25% of sinusitis cases.

Other possible bacteria include: • Other streptococcal strains • Staphylococcus aureus • P. aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter species, and Escherichia coli • Fusobacterium nucleatum and Prevotella intermedia)

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Bacterial lower respiratory tract infections Done By: Rana Abu Zuhri

Lower respiratory tract infection The lower respiratory tract consists of the trachea ,bronchial tubes, the bronchioles, and the lung. Lower respiratory tract infections are generally more serious than upper respiratory infections. LRIs are the leading cause of death among all infectious diseases. The most common LRIs are bronchitis, pneumonia, and empyema.

Acute Bronchitis Bronchitis is the inflammation of the mucus membranes of the bronchi. Usually caused by viruses and rarely by bacteria. Characteristic symptoms include cough, sputum production, shortness of breath ,wheezing. Bacteria like 1. mycoplasma pneumoniae, 2.streptococcus pneumoniae, 3.bordatella pertussis and 4.chlamydophila pneumoniae account for about 10% of acute cases .

Diagnosis is by clinical examination and sometimes microbiological examination of the sputum. Treatment for acute bronchitis is typically symptomatic, as viruses cause most cases of it, antibiotics should not be used unless microscopic examination of gram-stained sputum reveals large numbers of bacteria.

Chronic bronchitis Chronic bronchitis, a type of chronic obstructive pulmonary disease . Cigarette smoking is the most common cause, followed by air pollution and occupational exposure to irritants.

Pneumonia Pneumonia can be generally defined as inflammation of the lung parenchyma, in which consolidation of the affected part and a filling of the alveolar air spaces with exudate. Often pneumonia begins after an upper respiratory tract infection (an infection of the nose and throat) ,pneumonia begin after 2 or 3 days. Sign and symptoms: fever ,rigors ,cough, dyspnea ,chest pain, hemoptysis

Typical pneumonia Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, bile-soluble aerotolerant anaerobic member of the Streptococci. S. pneumoniae was recognizedas a major cause of pneumonia.

Atypical pneumonia The bacteria responsible for causing atypical pneumonia are: 1.Chlamydophila pneumoniae, 2.Mycoplasma pneumoniae and 3.Legionella pneumophila. Most forms of atypical pneumonia are characterized by mild symptoms; However, the pneumonia caused by Legionella sometimes result in severe symptoms. The mortality rate of Legionella induced pneumonia is quite high.

Community acquired pneumonia Community acquired pneumonia : is the 4th most widespread cause of fatality. 85 percent of the CAP episodes occur due to typical pathogens like 1.Haemophilus influenza, 2.Moraxella catarrhalis and 3.Streptococcus pneumoniae. The other 15 percent of the CAP cases occur due to atypical pathogens like 1.Legionella species, 2.Chlamydia pneumoniae and 3.Mycoplasma pneumoniae. In rare cases the condition can also be triggered by: 1.Acinetobacter, 2.Pseudomonas aeruginosa and 3.Enterobacter.

Hospital-Acquired Pneumonia Develops at least 48 h after hospital admission. The most common pathogens are : 1.gram-negative bacilli mainly : Enterobacter sp, Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, Proteus sp, Acinetobacter sp. 2.Staphylococcus aureus, 3.Haemophilus influenzae.

Pseudomonas aeruginosa, which is especially common in pneumonias acquired in intensive care settings and in patients with cystic fibrosis, neutropenia, advanced AIDS, and bronchiectasis. Drug-resistant organisms are an important concern. Etiology: The most common cause is microaspiration of bacteria that colonize the oropharynx and upper airways in seriously ill patients.

Other types Tuberculosis can cause pneumonia in some people, especially those with a weak immune system. Pneumonia caused by Yersinia pestisis usually called pneumonic plague.

Diagnosis: Chest x-ray and clinical criteria. Sometimes bronchoscopy, blood cultures. Treatment: Empirically chosen antibiotics active against resistant gram-negative and gram-positive organisms If the diagnosis is suspected, treatment is with antibiotics that are chosen empirically based on local sensitivity patterns.

Microbiology Lab