Podcast
Questions and Answers
What is a characteristic feature of Staphylococcus aureus?
What is a characteristic feature of Staphylococcus aureus?
Which transmission method is associated with Streptococcus pyogenes?
Which transmission method is associated with Streptococcus pyogenes?
Which disease is NOT caused by Staphylococcus aureus?
Which disease is NOT caused by Staphylococcus aureus?
What is a common source of infection for Staphylococcus aureus?
What is a common source of infection for Staphylococcus aureus?
Signup and view all the answers
What is the first-line treatment for serious invasive infections due to MRSA?
What is the first-line treatment for serious invasive infections due to MRSA?
Signup and view all the answers
Which of the following organisms is catalase negative?
Which of the following organisms is catalase negative?
Signup and view all the answers
What infection is most likely caused by Staphylococcus aureus in children under 4 years of age?
What infection is most likely caused by Staphylococcus aureus in children under 4 years of age?
Signup and view all the answers
What factors contribute to antibiotic resistance in Staphylococcus aureus?
What factors contribute to antibiotic resistance in Staphylococcus aureus?
Signup and view all the answers
Which of the following syndromes is characterized by multisystem toxicity following soft tissue infection and may lead to shock and organ failure?
Which of the following syndromes is characterized by multisystem toxicity following soft tissue infection and may lead to shock and organ failure?
Signup and view all the answers
What bacterial species is primarily responsible for causing neonatal meningitis and septicemia?
What bacterial species is primarily responsible for causing neonatal meningitis and septicemia?
Signup and view all the answers
Which Clostridium species is known to produce botulinum toxin, leading to botulism?
Which Clostridium species is known to produce botulinum toxin, leading to botulism?
Signup and view all the answers
Which of the following bacteria is a common cause of urinary tract infections and can also lead to neonatal meningitis?
Which of the following bacteria is a common cause of urinary tract infections and can also lead to neonatal meningitis?
Signup and view all the answers
Among the following bacteria, which one is identified as being non-motile?
Among the following bacteria, which one is identified as being non-motile?
Signup and view all the answers
Which of the following conditions is NOT typically associated with Clostridium perfringens infection?
Which of the following conditions is NOT typically associated with Clostridium perfringens infection?
Signup and view all the answers
Which bacterial genus is primarily responsible for dental caries?
Which bacterial genus is primarily responsible for dental caries?
Signup and view all the answers
Which of the following Gram-positive bacilli is identified as an obligate anaerobe?
Which of the following Gram-positive bacilli is identified as an obligate anaerobe?
Signup and view all the answers
Study Notes
Overview of Bacterial Infections
- Bacteria are classified as gram-positive or gram-negative.
- Gram-positive cocci are arranged in clusters, are catalase-positive, and coagulase-positive.
- Gram-positive cocci are also arranged in chains. These are catalase-negative.
- Staphylococcus aureus is a facultative anaerobe found in healthy carriers. Transmission is skin-to-skin, contact with pus, and contact with objects.
- Diseases caused by S. aureus include bacteremia, endocarditis, pneumonia, meningitis, skin and soft tissue infections, food poisoning, and major bone infections.
Staphylococcus Aureus
- Gram positive cocci arranged in grape-like clusters
- Catalase-positive
- Coagulase-positive
- Facultative anaerobe
Sources of Infection
- Healthy carriers harbor bacteria in the nose, throat, skin, and under the nails.
Mode of Transmission
- Contact with pus from an infected wound
- Skin-to-skin contact with an infected person
- Contact with objects used by an infected person (e.g., towels, sheets, clothing, or athletic equipment)
Diseases Caused by Staphylococcus Aureus
- Bacteremia
- Endocarditis
- Pneumonia
- Meningitis
- Skin and soft tissue infections
- Food poisoning
- Scalded skin syndrome
- Major bone and joint infections like osteomyelitis and septic arthritis
- Urinary tract infections
Antibiotic Resistance
- Antibiotic resistance is widespread in S. aureus, including Methicillin-Resistant S. aureus (MRSA).
- MRSA is resistant to certain antibiotics, including methicillin.
- First-line treatment for serious invasive infections caused by MRSA includes glycopeptide antibiotics(vancomycin and teicoplanin).
Streptococcus pyogenes
- Gram-positive cocci arranged in chains
- Catalase-negative
- Mode of transmission includes inhalation of respiratory droplets, skin contact with infectious lesions, and contact with contaminated objects, surfaces, or dust.
- Diseases include:
- Streptococcal pharyngitis and tonsillitis
- Scarlet fever
- Skin infections (impetigo)
- Erysipelas
- Invasive skin infection
- Cellulitis
- Streptococcal Toxic Shock Syndrome (TSS)
Other Gram-positive cocci
-
Streptococcus pneumoniae
- Causes pneumonia, otitis media, sinusitis, and meningitis
Streptococcus viridans
- Dental caries, bacteremia
- Subacute bacterial endocarditis
- Neonatal meningitis (and Neonatal pneumonia) occurs from transmitted during the birth canal.
Clostridium
- Gram-positive bacilli
- Obligate anaerobe
- Clostridium botulinum produces botulinum toxin in food or wounds and causes botulism
- Clostridium perfringens cause a range of symptoms- cellulitis, fasciitis, necrotic enteritis, gas gangrene
- Clostridium tetani causing tetanus
- Clostridium difficile causes antibiotic associated diarrhea
Gram-Negative Bacteria
- Includes diplococci, coccobacilli, bacilli, comma shaped
- Examples: Escherichia coli, Klebsiella pneumoniae, Salmonella, Neisseria, Helicobacter pylori
Escherichia coli
- Gram negative bacilli
- Facultative anaerobe
- Peritrichate flagella
- Ferments lactose
- Common in the human lower intestine
- Some serotypes cause serious forms of gastroenteritis, Uropathogenic E. coli is a major cause of urinary tract infections.
- Can also causes neonatal meningitis.
Klebsiella pneumoniae
- Gram negative bacilli
- Facultative anaerobe
- Non motile
- Diseases caused by K. pneumonia include:
- Pneumonia
- Urinary tract infections
- Sepsis
- Wound infection
- Meningitis
Salmonella
- Gram-negative bacilli
- Facultative anaerobes
- Do not ferment lactose
- Most infections are due to ingestion of contaminated food or water
- Typhoidal serotypes (e.g., Typhoid fever) only transfer from human to human
Neisseria
- Gram-negative diplococci
- Oxidase-positive and aerobic
- Important pathogens include N. meningitides and N. gonorrhoeae
- N. gonorrhoeae causes the sexually transmitted genitourinary infection gonorrhoea
- N. meningitides causes meningitis and other forms of meningococcal disease such as meningococcemia
Helicobacter pylori
- Gram-negative spiral (helical) shaped bacilli
- Usually found in the stomach
- Has four to six unipolar flagella for penetrating stomach mucus lining
- May cause no symptoms but can lead to gastritis, ulcers in the stomach or the first part of the small intestine (duodenum)
- Associated with the development of certain stomach cancers.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers key concepts related to bacterial infections, focusing on the classification and characteristics of gram-positive and gram-negative bacteria. Special emphasis is placed on Staphylococcus aureus, its modes of transmission, and diseases it can cause. Test your knowledge about the sources and risks associated with these infections.
