Mycobacterium Infections of the GI Tract

The low pH of stomach fluid (pH 1.5-3.0) has antimicrobial properties, helping to prevent infection.

Normal flora prevents infection by competing with pathogens for space and resources, and by producing antimicrobial compounds.

The muscular surface of the GI tract ensures movement, termed peristalsis, which helps to remove pathogens and prevent infection.

<p>Mucus provides mechanical protection against infection by trapping pathogens and preventing them from reaching the epithelial surface.</p> Signup and view all the answers

<p>Secretory IgA is an antibody that provides immune protection by neutralizing pathogens and preventing infection.</p> Signup and view all the answers

<p>The incubation period of 'intoxication' is 1-2 hours, whereas the incubation period of 'infection' is 2-7 days.</p> Signup and view all the answers

<p>Toxin-producing bacteria, such as Clostridium perfringens, can produce toxins in the large intestine, leading to diarrhoea.</p> Signup and view all the answers

<p>Antibiotic treatment can make the infection worse, so it is generally not recommended.</p> Signup and view all the answers

<p>Diarrhoea is characterized by stools of a loose or liquid consistency, occurring more frequently than is normal for the individual.</p> Signup and view all the answers

<p>The type of food eaten can give a clue to the aetiology of the infection, as certain foods are more commonly associated with specific pathogens.</p> Signup and view all the answers

<p>The lower respiratory tract is essentially sterile, making it more susceptible to severe infections, whereas the upper respiratory tract is continuously exposed to airborne pathogens and has a more robust immune response.</p> Signup and view all the answers

<p>Airborne pathogens are a major portal of entry for respiratory infections, and they are easily transmitted from human to human through circulation within a community, often through aerosolized contaminated water.</p> Signup and view all the answers

<p>Normal flora in the upper respiratory tract, including fungi and bacteria, can be disrupted by viral infections, antibiotics, injury, or invasive testing, leading to opportunistic infections.</p> Signup and view all the answers

<p>Water can be a source of respiratory infections, particularly through contaminated water that is aerosolized and inhaled, leading to infections such as Legionellosis.</p> Signup and view all the answers

<p>Fungal infections, such as Aspergillus and Pneumocystis, are particularly dangerous in immunocompromised patients, and can cause problems with diagnosis due to overgrowth, making timely diagnosis and treatment challenging.</p> Signup and view all the answers

<p>‘rice-water stool’</p> Signup and view all the answers

<p>Production of toxins A and B, which cause areas of necrosis in the intestinal wall</p> Signup and view all the answers

<p>Blood/mucus in stool with abdominal cramps</p> Signup and view all the answers

<p>Weeks</p> Signup and view all the answers

<p>Vibrio Spp Thioshulphate citrate bile salts (TCBS) Agar</p> Signup and view all the answers

<p>E. coli O157:H7</p> Signup and view all the answers

<p>Pseudomembranous colitis</p> Signup and view all the answers

<p>The most severe form of infection</p> Signup and view all the answers

<p>Detection of toxin from faeces using enzyme immunoassay</p> Signup and view all the answers

<p>To distinguish between Salmonella, Shigella, and other non-pathogenic bacteria</p> Signup and view all the answers

<p>Acute bloody diarrhoea is characterized by the sudden onset of diarrhoea with obvious blood present. The common bacterial causes of this condition include Campylobacter spp., Shigella spp., Shiga-toxin-producing Escherichia coli (STEC), and Salmonella spp.</p> Signup and view all the answers

<p>Persistent diarrhoea is defined as diarrhoea that lasts for more than 14 days but fewer than 30 days. Protozoa such as Giardia spp., Cryptosporidium spp., Cyclospora cayetanensis, and Microsporidia spp. are commonly implicated in this condition.</p> Signup and view all the answers

<p>Acute diarrhoea with vomiting, also known as food poisoning, is characterized by the sudden onset of symptoms (within 1-4 hours) and can be severe in patients, especially infants and children. The common microbial causes of this condition include Bacillus cereus, norovirus, adenovirus, rotavirus, Vibrio spp., Staphylococcus aureus, and Clostridium perfringens.</p> Signup and view all the answers

<p>The primary difference between acute and chronic diarrhoea is the duration of the condition, with acute diarrhoea lasting less than 30 days and chronic diarrhoea lasting more than 30 days. Chronic diarrhoea is a major clinical feature and a leading cause of morbidity and mortality in uncontrolled HIV infection.</p> Signup and view all the answers

<p>Laboratory diagnosis is crucial in determining the underlying cause of diarrhoea, and the choice of diagnostic tests depends on the possible aetiology of the condition.</p> Signup and view all the answers

<p>The primary reservoir of <strong>Campylobacter jejuni</strong> is animals, and the common modes of transmission include ingestion of contaminated food, direct contact with pets that harbor the organism, and contaminated water and unpasteurized milk.</p> Signup and view all the answers

<p>The optimal temperature for the growth of <strong>C. jejuni</strong> is 42°C, and the optimal oxygen environment is between 5 and 10 percent.</p> Signup and view all the answers

<p>The most common source of <strong>Campylobacter</strong> contamination is undercooked poultry, and the primary mode of transmission in the UK is ingestion of contaminated food.</p> Signup and view all the answers

<p>The two most common strains of <strong>Salmonella</strong> isolated in the UK are <strong>S. enteritidis</strong> and <strong>S. typhimurium</strong>, and the primary mode of transmission is ingestion of contaminated food.</p> Signup and view all the answers

<p>Maldi-TOF is used for the confirmation of <strong>Campylobacter</strong> spp.</p> Signup and view all the answers

<p>The primary difference between <strong>Campylobacter</strong> and <strong>Salmonella</strong> is that <strong>Campylobacter</strong> has animals as its primary reservoir, while <strong>Salmonella</strong> has both animal and human reservoirs, and the modes of transmission differ accordingly.</p> Signup and view all the answers

<p><strong>Campylobacter Selective Agar (CAMPY)</strong> is used for the selective isolation of <strong>Campylobacter</strong> spp. by inhibiting the growth of normal faecal flora.</p> Signup and view all the answers

<p>The primary mode of transmission of <strong>Salmonella</strong> in the UK is ingestion of contaminated food, and human-to-human transmission is also an important mode of transmission.</p> Signup and view all the answers

<p>Nucleic acid detection by PCR is a less common method used for the diagnosis of <strong>Campylobacter</strong> and <strong>Salmonella</strong> infections.</p> Signup and view all the answers

<p>Direct microscopy on faeces is a common method used for the diagnosis of <strong>protozoa</strong> and <strong>helminths</strong> infections.</p> Signup and view all the answers