Sketchy Microbiology

Questions and Answers

What role does urease play in the survival of Helicobacter pylori in the stomach?

It promotes the growth of gastric mucosa.

It produces cytotoxins to destroy stomach cells.

It enhances transmission through fecal-oral routes.

It neutralizes stomach acid, allowing survival. (correct)

Which of the following diseases is primarily associated with Helicobacter pylori infection?

Celiac disease

Type 2 diabetes

Irritable bowel syndrome

Chronic gastritis (correct)

What is a characteristic feature of Helicobacter pylori?

It is a Gram-positive cocci.

It thrives in aerobic conditions.

It is motile with flagella. (correct)

It lacks urease activity.

Which biotype of Helicobacter pylori is known for producing vacuolating cytotoxins?

Type I Signup and view all the answers

What method is NOT typically recommended for the treatment of Helicobacter pylori infection?

Increased gastric acid production Signup and view all the answers

What is the primary transmission route for Helicobacter pylori?

Fecal-oral and oral-oral Signup and view all the answers

Which of the following is a serious complication associated with Helicobacter pylori infection?

Gastric adenocarcinoma Signup and view all the answers

How is the new vaccine designed to prevent Helicobacter pylori infections primarily effective?

By inducing an immune response against the bacteria Signup and view all the answers

Which bacteria is characterized by asymmetrical arthritis and proctitis?

Neisseria gonorrhoeae Signup and view all the answers

What is the significance of detecting intracellular gram-diplococci in PMNs?

Indicates an infection by Neisseria gonorrhoeae Signup and view all the answers

Which treatment option is primarily recommended for Neisseria gonorrhoeae infection?

Ceftriaxone Signup and view all the answers

What feature distinguishes Klebsiella pneumoniae from Enterobacter and Serratia?

Non-motile Signup and view all the answers

How does the capsule of Klebsiella pneumoniae affect its virulence?

Impairs phagocytosis Signup and view all the answers

Which of the following is a correct association for Klebsiella pneumoniae?

Community-acquired pneumonia in alcoholics Signup and view all the answers

What is one of the primary pathogens in nosocomial urinary tract infections?

Klebsiella pneumoniae Signup and view all the answers

What laboratory finding is typically associated with Salmonella species when cultured?

Black colonies on Hektoin agar Signup and view all the answers

Which additional testing is essential when treating a suspected Neisseria gonorrhoeae infection?

Testing for C. trachomatis Signup and view all the answers

What unique characteristic do Enterobacter and Serratia share?

Lactose fermenting ability Signup and view all the answers

What is the primary receptor for Lyme disease in the human body?

Skin Signup and view all the answers

Which symptom is characteristic of Stage 1 Lyme disease?

Target rash (bull's eye) Signup and view all the answers

Which of the following is used for the serodiagnosis of Lyme disease?

ELISA Signup and view all the answers

What is the most common treatment option for stage 1 Lyme disease?

Doxycycline Signup and view all the answers

Which complication may arise during Stage 2 of Lyme disease?

Myocarditis Signup and view all the answers

What preventative measure is suggested to avoid Lyme disease?

Using DEET on skin Signup and view all the answers

Which organism causes Leptospirosis?

Leptospira interrogans Signup and view all the answers

How is Leptospira interrogans primarily transmitted?

Contact with animal urine in water Signup and view all the answers

What birth defect is associated with anterior bowing of the tibia?

Saber-shins Signup and view all the answers

Which method is NOT typically used for diagnosing Chlamydia infections?

Culture on inert media Signup and view all the answers

What type of organism is Chlamydia trachomatis classified as?

Obligate intracellular bacteria Signup and view all the answers

How is trachoma primarily transmitted?

Hand-to-eye contact Signup and view all the answers

Which of the following statements about Chlamydia diagnostics is true?

Cytoplasmic inclusions are visible in Giemsa stained smears. Signup and view all the answers

Which of the following diseases is NOT associated with Chlamydia serotypes D-K?

Lymphogranuloma venereum Signup and view all the answers

Which feature characterizes the infective form of Chlamydia?

Elementary bodies Signup and view all the answers

What is a common symptom of a Chlamydia infection in neonates?

Staccato cough Signup and view all the answers

Which of these features is consistent with Chlamydia's inability to produce energy independently?

Obligate intracellular lifestyle Signup and view all the answers

Which condition is characterized by watertight discharge and is associated with Chlamydia infections?

Cervicitis Signup and view all the answers

Which bacterium is associated with dental carries and infective endocarditis?

Streptococcus mutans Signup and view all the answers

What characteristic does Enterococcus faecium display that makes it more dangerous than Enterococcus faecalis?

Higher pathogenic potential Signup and view all the answers

What is a predisposing condition for infective endocarditis caused by Streptococcus mutans?

Dental work without prophylactic antibiotics Signup and view all the answers

Which method is primarily used for diagnosing infections caused by Bacillus cereus?

PCR and serology Signup and view all the answers

What type of toxin does Bacillus cereus produce that leads to fast-acting vomiting and diarrhea?

Emetic toxin Signup and view all the answers

What antibiotic combination is recommended for treating infective endocarditis associated with Streptococcus mutans?

Penicillin G with aminoglycosides Signup and view all the answers

What characteristic is common to both Enterococcus faecalis and faecium?

Hydrolyze esculin in 40% bile Signup and view all the answers

Which of the following is not a disease associated with Enterococcus species?

Gastrointestinal anthrax Signup and view all the answers

What advantage does Enterococcus have in terms of its growth in selective media?

Growth in high NaCl concentrations Signup and view all the answers

What is the primary mode of transmission for both Streptococcus mutans and Enterococcus species?

Endogenous transmission Signup and view all the answers

Study Notes

Streptococcus mutans

Gram-positive, catalase-negative, alpha-hemolytic bacteria; non-encapsulated and optochin resistant.
Reservoir found in the human oropharynx as normal flora; transmission is endogenous.
Causes dental caries through dextran-mediated adherence of oral flora, forming plaque.
Infective endocarditis can occur, presenting symptoms include malaise, anorexia, night sweats, and weight loss; risks include damaged heart valves and poor dental hygiene.
Treatment involves penicillin G with aminoglycosides; prophylactic antibiotics recommended before dental work for high-risk patients.

Enterococcus (Group D Strep)

Includes species Faecalis (common) and Faecium (more dangerous); gram-positive, catalase-negative, PYR positive, cocci in chains.
Reservoirs include the human colon, urethra, and female genital tract; endogenous transmission.
Associated diseases involve chronic necrotizing infection and Wool Sorter's Disease, a severe pneumonia.
Diagnosed through Gram stain and culture; treatment includes fluoroquinolones or doxycycline, and vaccination is recommended for high-risk occupations.

Bacillus cereus

Found in nature and primarily transmitted through foodborne intoxication, often linked to improperly handled fried rice.
Pathogenesis includes emetic and diarrheal toxins leading to rapid vomiting and diarrhea.
Diagnosis typically involves identifying intracellular gram-negative diplococci in neutrophils; treatment requires ceftriaxone while considering co-infection.

Enterobacteria (Enterobacter cloacae, Serratia marcescens, Klebsiella pneumoniae)

All are gram-negative, lactose fermenters that appear as pink colonies on MacConkey agar, multi-drug resistant, causing pneumonia and UTIs.
Enterobacter and Serratia are motile; Serratia produces a characteristic red pigment.
Klebsiella pneumonia is nonmotile with a large capsule, notably associated with alcoholism, chronic lung disease, and aspiration pneumonia.
Diagnosis is through culture from sputum or urine; treatment usually includes third-generation cephalosporins with consideration for aminoglycosides.

Salmonella

Gram-negative rods, enterobacteriaceae, non-lactose fermenting, motile, and H2S producing.
Salmonella typhi treatment includes fluid replacement and antibiotics like doxycycline or ciprofloxacin; proper sanitation helps prevent infection.

Helicobacter pylori

Gram-negative, spiral-shaped, motile bacilli with urease positivity, commonly residing in the stomach near the pylorus.
Transmission occurs via fecal-oral or oral-oral routes; associated with chronic gastritis and duodenal ulcers, and linked to stomach cancer.
Diagnosis through serodiagnosis, treatment with antibiotics such as amoxicillin or clarithromycin.

Lyme Disease (Borrelia burgdorferi)

The leading tick-borne disease in the U.S., presenting in three stages: early localized, early disseminated, and late persistent.
Stage 1 includes flu-like symptoms and a characteristic "bull's eye" rash.
Stage 2 encompasses heart and neurological issues; stage 3 involves severe fatigue and migratory arthritis.
Diagnosis via ELISA and confirmation with Western blot; treatment typically includes doxycycline.

Leptospira interrogans

Spirochetes with a question mark shape transmitted through contact with contaminated water, causing potential severe infections.
Reservoir includes wild and domestic animals; notable symptoms may involve skeletal deformities and dental anomalies.

Chlamydia trachomatis

Obligate intracellular bacteria common in human genital tracts, transmitted sexually and perinatally.
Associated with various STDs, notable for causing watery discharge and pelvic inflammatory disease, as well as conjunctivitis and pneumonia in neonates.
Diagnosis made through cytoplasmic inclusions via various staining methods; treated with antibiotics like doxycycline.

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Description

Test your knowledge about Streptococcus mutans, including its distinguishing features, transmission methods, and associated diseases such as dental caries. This quiz will cover relevant characteristics and illustrations to help reinforce your understanding of its role in oral health.