Staphylococcus Species Overview
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Questions and Answers

Which symptom is commonly associated with Toxic Shock Syndrome caused by Staphylococcus aureus?

  • Petechiae (correct)
  • Nausea and diarrhea
  • High blood pressure
  • Blistering of skin

    • What is the characteristic colony appearance of Staphylococcus aureus on NAM agar?

  • Greenish and slimy
  • Pink and smooth
  • Golden and convex (correct)
  • White and flat

    • Which test differentiates Staphylococcus aureus from Staphylococcus epidermidis?

  • Mannitol salt agar growth (correct)
  • Thioglycolate test
  • Catalase test
  • Gram staining

    • What would indicate a non-fermenter in Staphylococcus epidermidis growth on mannitol salt agar?

    <p>Pink coloration</p> Signup and view all the answers

    Which molecular test is commonly used to amplify genes associated with bacterial strains like MRSA?

    <p>RT-PCR</p> Signup and view all the answers

    What is the Gram stain result for both Staphylococcus aureus and Staphylococcus epidermidis?

    <p>Gram positive, cocci in cluster arrangement</p> Signup and view all the answers

    Which condition is Staphylococcus epidermidis commonly associated with in at-risk patients?

    <p>Infective endocarditis</p> Signup and view all the answers

    Which test is NOT used to identify Staphylococcus epidermidis?

    <p>Coagulase test</p> Signup and view all the answers

    What is the primary treatment for staphylococcal infections?

    <p>Drain and clean infected areas with anti-bacterials</p> Signup and view all the answers

    Which of the following antibiotics is classified as a semi-synthetic penicillin?

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

    What type of organism causes strep throat?

    <p>Streptococcus pyogenes</p> Signup and view all the answers

    Which of the following symptoms is commonly associated with Streptococcus pneumoniae infections?

    <p>Respiratory distress</p> Signup and view all the answers

    How is Vibrio cholerae primarily diagnosed?

    <p>Culturing from stool or vomiting samples</p> Signup and view all the answers

    What type of agar is used for culturing Vibrio cholerae due to its specificity?

    <p>Thiosulfate citrate bile salt sucrose agar (TCBS)</p> Signup and view all the answers

    What is a key symptom of Helicobacter pylori infection?

    <p>Bloating and cramps</p> Signup and view all the answers

    What is a treatment option for food poisoning caused by Campylobacter jejuni?

    <p>Food poisoning typically resolves self-limiting</p> Signup and view all the answers

    What type of Gram staining result is expected for Treponema pallidum?

    <p>Gram-negative spirochetes</p> Signup and view all the answers

    Which stage of syphilis presents with a maculopapular rash?

    <p>Secondary stage</p> Signup and view all the answers

    Which of the following antibiotics can develop resistance when treating Helicobacter pylori?

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

    What laboratory test confirms the presence of coagulase-negative Staphylococcus?

    <p>Latex agglutination test</p> Signup and view all the answers

    What is the main causative agent of cholera?

    <p>Vibrio cholerae</p> Signup and view all the answers

    Which of the following tests is used to differentiate between lactose fermenters and non-fermenters?

    <p>MacConkey agar</p> Signup and view all the answers

    What is the primary treatment for Herpes Zoster?

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

    Which symptom is characteristic of infectious mononucleosis?

    <p>Cervical lymphadenopathy</p> Signup and view all the answers

    What type of rash is typically seen in Varicella?

    <p>Macular rash leading to vesicles</p> Signup and view all the answers

    In what age group is Herpes Zoster most likely to recur?

    <p>Adults over 60</p> Signup and view all the answers

    What diagnostic method is most appropriate for detecting Cytomegalovirus?

    <p>PCR for CMV early antigen detection</p> Signup and view all the answers

    Which treatment option is specifically recommended for prophylaxis in transplant patients against Cytomegalovirus?

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

    What is a primary cause of malaria in sub-Saharan regions?

    <p>Plasmodium falciparum</p> Signup and view all the answers

    What is the primary symptom sequence of a malarial paroxysm?

    <p>Cold, fever, sweating</p> Signup and view all the answers

    What type of vaccine is Varilrix?

    <p>Live-attenuated vaccine</p> Signup and view all the answers

    What is the characteristic presentation of primary amoebic meningoencephalitis caused by Naegleria fowleri?

    <p>Headaches and delirium</p> Signup and view all the answers

    Which of the following treatments is NOT associated with Plasmodium vivax?

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

    Which herpesvirus is associated with causing oral hairy leukoplakia?

    <p>Epstein-Barr Virus</p> Signup and view all the answers

    Which of the following treatments is recommended for falciparum malaria that shows resistance to artemisinin?

    <p>Combination therapy with artemether and mefloquine</p> Signup and view all the answers

    What is the significance of the Dieterle stain in diagnosing certain infections?

    <p>It allows visualization of spirochaetes against a yellow background.</p> Signup and view all the answers

    Which bacterial treatment is recommended for early Lyme disease?

    <p>Doxycycline or tetracycline as first-line therapy.</p> Signup and view all the answers

    What is the primary method of diagnosing influenzavirus infections?

    <p>Direct nasal swab followed by PCR.</p> Signup and view all the answers

    Which of the following is NOT a symptom of Lyme disease?

    <p>Severe respiratory problems lasting over two weeks.</p> Signup and view all the answers

    What type of virus is the influenzavirus classified as?

    <p>ssRNA negative-sense virus with HA/NA antigens.</p> Signup and view all the answers

    What is the primary mode of transmission for herpes-simplex virus type 2?

    <p>Direct intimate contact.</p> Signup and view all the answers

    Which diagnostic method is least sensitive for detecting treponemal infections?

    <p>FTA ABS testing for fluorescent treponemal antibodies.</p> Signup and view all the answers

    For which condition is IV penicillin commonly administered?

    <p>Tertiary syphilis.</p> Signup and view all the answers

    Which of the following laboratory techniques is used for direct detection of adenovirus?

    <p>PCR and sequencing alignment.</p> Signup and view all the answers

    What symptom is specifically associated with acute herpes simplex viral infections?

    <p>Prodromal paraesthesia before lesions appear.</p> Signup and view all the answers

    What is a typical treatment approach for adenovirus-related conjunctivitis?

    <p>Increased chlorine in swimming pools.</p> Signup and view all the answers

    What is the preferred method for confirming a current infection of herpes simplex in a symptomatic patient?

    <p>PCR using HSV1-2 specific primers.</p> Signup and view all the answers

    What is the primary cause of secondary bacterial pneumonia during influenza infections?

    <p>Weakness of the immune system during influenza.</p> Signup and view all the answers

    What is the most significant complication associated with the treatment of fungal infections with Amphotericin B?

    <p>It has a 97% death rate even with treatment.</p> Signup and view all the answers

    Which symptom is commonly associated with Giardiasis caused by Giardia intestinalis?

    <p>Eggy breath.</p> Signup and view all the answers

    What is the primary method of diagnosing Balantidiasis?

    <p>Presence of cysts in stool samples.</p> Signup and view all the answers

    Which treatment is effective against Ascaris lumbricoides infection?

    <p>Albendazole.</p> Signup and view all the answers

    What is a key characteristic of Acute Invasive Aspergillosis (AIA)?

    <p>Has a 50-100% mortality rate.</p> Signup and view all the answers

    Which treatment option is recommended for Trichinella spiralis infection?

    <p>Albendazole.</p> Signup and view all the answers

    Which diagnostic method is most important for confirming a diagnosis of Aspergillus species?

    <p>Sputum and blood cultures.</p> Signup and view all the answers

    Which factor contributes to the high mortality rate in patients with Acute Invasive Aspergillosis?

    <p>Delay in treatment administration.</p> Signup and view all the answers

    Which of the following agents is used in the treatment of Taeniasis caused by Taenia solium?

    <p>Niclosamide.</p> Signup and view all the answers

    What role does Lactobacillus spp. play in the new therapy investigations for Giardiasis?

    <p>It converts conjugated bile salts into free bile salts.</p> Signup and view all the answers

    What is a common diagnosis method for Non-invasive Aspergillosis?

    <p>Patient symptom history and X-rays.</p> Signup and view all the answers

    Which parameter is not typically used in the diagnosis of Taenia infections?

    <p>Serological tests for antibodies.</p> Signup and view all the answers

    What symptom characterizes allergic bronchopulmonary aspergillosis (ABPA)?

    <p>Brown mucus plugs.</p> Signup and view all the answers

    Which of the following is true about the diagnostic approach for Giardia intestinalis?

    <p>Stool sample must show presence of trophozoites.</p> Signup and view all the answers

    What is a common treatment for mucosal candidiasis in immunocompromised patients?

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

    Which factor is NOT a predisposing condition for skin candidiasis?

    <p>High fiber diet</p> Signup and view all the answers

    Which method is used to confirm the presence of Candida albicans using culture?

    <p>Sabouraud's with Cycloheximide</p> Signup and view all the answers

    In the case of invasive candidiasis, which symptom is least likely to be observed?

    <p>Visible plaques in the mouth</p> Signup and view all the answers

    What is the significance of a germ tube test in diagnosing Candida species?

    <p>It confirms the presence of Candida albicans specifically</p> Signup and view all the answers

    Which treatment option may be considered potentially toxic for patients with Candida infections?

    <p>IV Amphotericin B</p> Signup and view all the answers

    Which of the following describes Cryptococcus neoformans infection?

    <p>Associated with avian environments and is more severe in HIV patients</p> Signup and view all the answers

    Which laboratory technique is used for the diagnosis of pulmonary cryptococcosis?

    <p>Latex agglutination for polysaccharide antigen</p> Signup and view all the answers

    Which population is most at risk for developing meningeal cryptococcosis?

    <p>Immunocompromised patients, particularly those with HIV</p> Signup and view all the answers

    What does the presence of white, creamy brown colonies on Sabouraud's agar indicate?

    <p>Possible Candida infection</p> Signup and view all the answers

    Which symptom is commonly associated with vaginal candidiasis?

    <p>Red itchy area with white discharge</p> Signup and view all the answers

    What type of infections can invasive candidiasis lead to in immunocompromised patients?

    <p>Meningitis and renal abscess</p> Signup and view all the answers

    What is the primary mode of acquiring Cryptococcus neoformans?

    <p>Inhalation of spores from soil or bird droppings</p> Signup and view all the answers

    Which therapeutic class does echinocandins belong to?

    <p>Antifungals targeting cell wall synthesis</p> Signup and view all the answers

    Study Notes

    Staphylococcus Species

    • Staphylococcus aureus causes skin and soft tissue infections (SSTIs), conjunctivitis, impetigo, rashes, food poisoning, infective endocarditis, UTIs, toxic shock syndrome, osteomyelitis, and community-acquired pneumonia. Symptoms vary depending on the infection, potentially including pus-filled lesions, skin rashes, eye inflammation, nausea, diarrhea, vomiting, fever, low blood pressure, petechiae, and heart murmurs.

    • Staphylococcus epidermidis causes SSTIs, forming biofilms on catheters, UTIs, and infective endocarditis. Patients with IV drug use or any skin-penetrating devices are high-risk.

    Diagnosis of Staphylococcus Species

    • Staphylococcus aureus

      • Sample collection from sterile or non-sterile sites, evaluating for common skin flora.
      • Colony isolation on nutrient agar (NAM): Observe gold, convex 2µm colonies.
      • Gram stain: Gram-positive cocci in clusters.
      • Blood agar: Alpha or beta hemolysis.
      • Mannitol salt agar: Mannitol fermenter (yellow).
      • Thioglycolate: Facultative aerobe.
      • Catalase test: Positive (bubbles).
      • Latex agglutination test: Coagulase positive.

    • Staphylococcus epidermidis

      • Sample collection from sterile or non-sterile sites, evaluating for common skin flora.
      • Colony isolation on nutrient agar (NAM): Observe white, convex 2µm colonies.
      • Gram stain: Gram-positive cocci in clusters.
      • Blood agar: Gamma hemolysis.
      • Mannitol salt agar: Non-fermenter (remains pink).
      • Thioglycolate: Facultative anaerobe.
      • Catalase test: Positive (bubbles).
      • Latex agglutination test: Coagulase negative.

    Molecular and Genotypic Testing

    • PCR/RT-PCR: Amplifies specific bacterial genes (e.g., 16S, MecA in MRSA) for identification and strain determination. Results can be analysed through Sanger sequencing and alignment to existing databases. Chromatogram quality can influence accuracy.

    • PFGE: Evaluates bacterial strain transmission and epidemiology.

    • MLST: Analyzes housekeeping and cell surface genes (e.g., spa) to identify bacterial strains.

    • MALDI-TOF MS: Time- and cost-effective method: Allows identification of protein fragments. A spectrum of protein fragments is produced by zapping samples in a well with a laser. Time of Flight is recorded and analyzed, separating molecules based on size. alignment to pre-existing BLAST database sequences can be conducted.

    Treatments for Staphylococcal Infections

    • General: Drain and clean infected areas (boils/SSTIs) with antimicrobials to decolonize. Autoclave patient bedding (Health-care-associated infections).

    • Antibiotics:

      • Semi-synthetic penicillins (Flucloxacillin, dicloxacillin)
      • Cephalosporins (Clindamycin, lincomycin, erythromycin)
      • MRSA Treatments (Clindamycin, minocycline, doxycycline, vancomycin - developing resistance)
      • Nosocomial MRSA (Rifampicin and Fusidic acid)
      • Newer (Linezolid, quinupristin/dalfopristin)

    Streptococcus Species

    • Streptococcus pyogenes causes strep throat, SSTIs, necrotizing fasciitis, scarlet fever, and rheumatic fever. Associated symptoms include sore throat/pharyngitis, swollen tonsils, temperature changes, rashes (scarlet fever), skin itching, cellulitis lesions, and other conditions.

    • Streptococcus pneumoniae causes pneumonia, bacterial meningitis, otitis media, and sinusitis. Characterized by respiratory distress, inflammation, earache, breathing obstruction, increased intracranial pressure, fever, and confusion.

    • Diagnosis (Streptococcus spp): - Sample acquisition (sterile/non-sterile, evaluate skin flora) - Colony isolation on NAM: Observe white convex 2µm colonies - Gram stain: Gram-positive cocci in chains. - Blood agar: Alpha or beta hemolysis. - Mannitol salt agar: Non-fermenter (pink) (pyogenes) - Thioglycolate: Facultative aerobe. - Catalase test: Negative. - Latex agglutination test: Coagulase negative (pyogenes).

      • Treat with Penicillin, amoxicillin, flucloxacillin

    Vibrio cholerae, Campylobacter jejuni, Helicobacter pylori

    • These pathogens cause various gastrointestinal infections, and the notes describe their respective causes, symptoms, diagnosis (including specific culture media and biochemical tests), and treatment procedures. The details are unique in terms of microbiology information, relevant aspects of diagnosis and treatments tailored for each causative pathogen.

    Treponema pallidum (Syphilis)

    • Syphilis progresses through four stages:

      1. Primary: Chancre formation, usually self-limiting.
      2. Secondary: Skin rash, systemic symptoms.
      3. Latent: Asymptomatic, but infectious.
      4. Tertiary: Severe organ damage (gummas, neuro-syphilis, endocarditis).

    • Diagnosis is primarily based on visual symptoms, dark-field microscopy (Dieterle stain), and serological tests (FTA-ABS).

    • Treatment is typically penicillin IV, tailored to the stage and severity of infection.

    Borrelia burgdorferi (Lyme Disease)

    • Lyme disease is characterized by a bullseye rash (erythema migrans), flu-like symptoms, and potential long-term complications (neurological, arthritic).

    • Diagnosed via blood tests (EIA, IFA, western blot), PCR, and possibly a blood smear.

    • Treatment typically involves antibiotics (long-term high dose for late-stage).

    Influenza Virus (Type A, B, and C), Adenovirus

    • These viruses cause various respiratory and other symptoms

    • Diagnosis involves testing for viral antigens (IFA), viral isolation, and PCR. Treatment is typically supportive care, and vaccine is type-specific for prevention.

    Herpesviruses (Alpha, Beta, Gamma)

    • The notes provide detailed information on herpes simplex viruses (HSV-1, HSV-2), varicella-zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV), including their subtypes, tropisms, causative diseases, symptoms, diagnosis, and treatment.

    Protozoa (Malaria, Naegleria fowleri, Balantidium coli, Giardia intestinalis)

    • These notes detail the causes, symptoms, diagnosis, and treatments of protozoan infections, differentiating between various Plasmodium species (Falciparum, Vivax, Ovale, Knowlesi, Malariae) , Naegleria fowleri, Balantidium coli, and Giardia intestinalis. Information relevant for diagnosis (microscopy, serology, PCR) and treatment is included.

    Helminths (Ascaris lumbricoides, Trichinella spiralis, Taenia solium)

    • These notes provide comprehensive information on roundworms and tapeworms, including causes, symptoms, diagnosis (stool samples, biopsies), and treatment (medication, potentially surgery).

    Fungi (Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans/gatti)

    • These notes describe fungal infections, including allergic bronchopulmonary aspergillosis (ABPA), non-invasive aspergillosis, acute invasive aspergillosis (AIA), superficial (oropharyngeal, skin, vaginal) and invasive candidiasis, and pulmonary/meningeal cryptococcosis, covering causes, symptoms, diagnosis (cultures, microscopy, serology), and specific treatment strategies for each type.

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    Description

    This quiz covers essential information about Staphylococcus species, particularly Staphylococcus aureus and Staphylococcus epidermidis. It includes details on their infections, symptoms, and diagnostic methods. Test your understanding of these important pathogens and their clinical implications.

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