Unit 6 Flashcards
The genome of a virus is composed of?
Any of the above
*Single-stranded DNA
*RNA
*double-stranded DNA
What requirements do viruses have for replications?
They must be inside a living cell
What is the correct sequence of viral infection of naked viruses?
Attachment, penetration, replication, cell lysis
When is the best time to collect a specimen for culture from a patient suspected of having a viral disease?
Less than 3 days after onset of symptoms
What is the composition of viral transport media?
Isotonic buffered saline with protein
What is an unsuitable temperature for virsuses because it allows the development of ice crystals?
-20C
All of the following methods are used by the laboratory to diagnose viral infections, except
Growth on artificial media
Which of the following describes cytopathic effects seen in viral culture?
The visual changes produced in an infected cell by a virus
The cytopathic effect demonstrating intranuclear inclusions is associated with
CMV
The noroviruses are most noted for producing
Gastroenteritis
Which of the following is the best description of a primary cell culture?
It is a culture where tissue is removed from an animal, arranged in a monolayer and in which very little cell division occurs
Which of the following describes a diploid cell culture that is not a primary culture?
It is a culture of cells that can divide, but passage is limited to about 50 generation
Which of the following is the description of continuous cell cultures?
Cells often have variable numbers of chromosomes and can be sub cultured indefinitely
What are giant multinucleated cells formed from cell fusion as a result of viral infection?
Syncytia
Severe acute respiratory syndrome (SARS) is caused by
Coronavirus
Adenoviruses produce all the following types of infection except
Meningitis
What type of genome do herpesviruses have?
- dsDNA
Which virus has been linked to Kaposi sarcoma?
Human herpesvirus 8
Which serologic marker would be expected to be found in the serum of someone successfully vaccinated against Hepatitis B virus (HBV)?
Anti-HBs
Presence of this HBV serologic marker indicates is highly infectious
HBs antigen
What virus causes genital herpes?
Herpes simplex virus type 2
Symptomatic congenital infection with CMV includes all the following except
Meningitis
Complications of EBV infection include all the following except
Acute glomerulonephritis
Which cancer is associated with EBV?
Burkitts lymphomas
What disease does the varicella zoster virus (VZV) cause?
Chickenpox
What type of cancer is associated with HPV?
Cervical
What virus is the most common cause of viral gastroenteritis in infants and children?
Rotavirus
Poliovirus is transmitted primarily by
Fecal-oral
Which one of the following viruses causes a viral hemorrhagic fever?
Ebola virus
What virus causes Hantavirus pulmonary syndrome?
Sin Nombre virus
What virus is the most common cause of Arboviral encephalitis in the world?
Japanese Encephalitis (JE) virus
What is the most common flavivirus infection in the United States?
St. Louis Encephalitis
What virus causes the measles?
Rubeola virus
What is the most common virus isolated from infant with lower respiratory infections and cause croup, bronchitis, bronchiolitis and interstitial pneumonia?
RSV
What virus is the major cause of common cold?
Rhinovirus
Which of the following is true of the virus the causes of AIDS?
Human retrovirus
What viral genus causes rabies?l
Lyssavirus
Which virus is a bloodborne pathogen?
Hepatitis C virus
What is a prion?
A proteinaceous infectious particle
What infectious agent causes Creutzfeldt-Jakob disease, Kuru and “mad cow” disease?
Prion
What infectious agent causes Creutzfeldt-Jakob disease, Kuru and “mad cow” disease?
Prion
What virus causes immune suppression in the host by targeting and destroying the hosts CD4+ T cells?
HIV
The classic example of a bite-wound infection is
Rabies
How is hepatitis B transmitted
Blood and body fluids
Which hepatitis virus is spread by the fecal-oral route?
Hepatitis A
Which hepatitis virus commonly leads to chronic hepatitis and cirrhosis, often requiring a live transplant, and causes a high risk for development of liver cancer?
Heptatits C
All of the following are identifiable viral agents of gastrointertitis except
CMV
The most common route of infection of laboratory workers with HBV and HIV is
Needle stick
Infection with CMV in non immune pregnant women can cause
Microencephalopathy
When reading culture plates from respiratory specimens, what must the microbiologist take into consideration?
The types of organisms normally found at the culture site
What does the presence of a-hemolytic colonies on a throat culture indicate?
These organisms are normal microbiota found in the pharynx
What should a microbiologist do if he or she finds a-hemolytic colonies on a properly collected sputum specimen on a patient suspected of having lobar pneumonia?
Do a full workup to identify the organism
A patients normal pharyngeal biota can be altered by all of the following except
Visiting a nursing home
All of the following factors can help the microbiologist differentiate between colonization and infection except
Presence of a pure culture or mixed biota on the culture plates
What is the most common cause of community-acquired pneumonia adults?
Streptococcus pneumonia
What is the cause of reduced clearance of respiratory secretions that predisposes people to respiratory infections?
All of the above
*obstruction by a foreign body
*alterations in the viscosity of the mucus
*immature anatomica development
What bacterium may cause up to 50% of all cases of pneumonia in the summer months?
Mycoplasma pneumonia
What is helpful when initiating antimicrobial therapy?
Knowing the pathogens most likely to cause a particular type of infection
Elements of the respiratory tract that can help prevent infection include
All of the above
*nasal hair
*normal microbiota
*coughing
All the following are virulence factors that allow microorganisms to produce disease, except
Mucus production
Why is pharyngitiis produced by group A streptococcus treated with antimicrobial agents?
To prevent rheumatic fever and acute glomerulonephritis
What are the two most frequently identified bacterial causes of community-acquired sinusitis?
Streptococcus pneumonia and haemophilus influenzae
Acute sinusitis usually occurs as a complication of
The common cold
What common condition will predispose individuals to acute sinusitis?
Allergies
All of the following are complications of acute sinusitis except
Acute pharyngitis
What organism are most frequently isolated from cultures of Individuals with otitis media?
Strepcoccus pneumonia and haemophilus influenza
What is the most common localized infection of the upper respiratory tract in preschool-age patients?
Otitis media
Why do most physicians treat otitis media empirically?
The predominant infection causing organisms are known
What organism is the predominant cause of epiglottis?
Haemophilus influenza
What is the most common complication of pertussis?
Pneumonia
What is the specimen of choice for recovery of Bordetella pertussis?
Nasopharyngeal swabs
What virus causes community-wide seasonal outbreaks of bronchiolitis in infants?
Respiratory syncytial virus
How is acute bronchitis differentiated from acute pneumonia?
The degree and extent of involvement of the lower respiratory tract with the infectious process
Most influenza epidemics and pandemics
Follow a recombination event in causative agents genome
What usually causes community-acquired pneumonias in children during the winter months?
Viral pathogens
Patient with influenzae virus infection are predisposed to
Secondary bacterial pneumonia
Nosocomial pneumonia is commonly caused by all of the following except
Streptococcus pneumonia
What is empyema?
A collection of Purulent fluid in the pleural space between the lung and the chest wall
What is a chronic pneumonia?
A pneumonia that appears to resolve clinically, but where radiographic lung abnormalities persist for a long period
What organism is the most common opportunistic pathogen that routinely infects patients with HIV/AIDS?
Pneumocystis jirovecii
All of the following are potentially pathogenic organisms found in the nasopharyngeal of healthy individuals except
Streptococcus mutans
What is the most common bacterium found on the skin’?
Coagulate-negative staphylococci
Which of the following organisms is responsible for for impetigo?
Streptococcus pyogenes
A group of swim team members breaks out in a rash folliculitis) the day after swimming at the pool. What organism is probably responsible for this outbreak?
Pseudomonas aeruginosa
What is a form of follicilitis in bearded men?
Sycosis Barbae
Which of these is an abscess that extends more deeply into the subcutaneous tissue and may have multiple draining sites?
Carbuncle
Besides antimicrobial therapy, how are most carbuncles treated?
Surgical drainage
What condition presents as a localized area of mildly painful erythema, warmth, and swelling of the skin with poorly demarcated margins?
Cellulitis
What is erysipelas?
A superficial form of cellulitis
What is the most well-known type of myonecrosis?
Gas gangrene
What condtion causes the nail margin to become painful, red, warm and swollen with pus?
Paronychia
What organism is known to cause severe necrotic cellulitis and primary sepsis?
Vibrio vulnificus
Purpura fulminant, a skin manifestation of disseminated intravascular coagulation, is associated with which condition?
Meningococcemia
What happen in the later stages of toxic shock syndrome as a result of the production of toxic shock syndrome toxin-1?
Desquamation
What causes scarlet fever?
Erythrogenic toxin
What organism produces “rat bite fever?”
Steptobacillus moniliformis
What organisms causes the Buruli ulcer?
Mycobactrium ulcerans
What is the best method of diagnosing scabies?
Skin scrapings
The clinical syndrome of Rocky Mountain spotted fever Can be confused with which of the following conditions?
Meningococcemia
A common cause of eumycetoma
Madurella sp.
What is a circumscribed, hyperkeratotic, rough-textured, painless papule called?
Wart
What disease results from a reactivation of the varicella-zoster virus that presents as vesicular eruption in a unilateral dermatomal distribution?
Shingles
What is hepatitis whitlow?
Primary herpetic lesions of the finger
What causes rubeola?
Paramyxovirus
What causes rubella?/
Togaviridae
What causes erythemia infectionsum?
Parvovirus
All of the following viruses cause a characteristic viral syndrome, which includes severe bleeding manifestations except
Junin virus
What is ringworm?
A fungal skin infection
What is thrush?
Oral candidiasis
What is swimmers itch?
Cercariae larvae penetrate human skin, causing dermatitis
In august, a 30 year old man presents with an ulcer on his leg with swelling of the lymph nodes in the surrounding area. He reports taking numerous hikes in the woods behind is house hunting rabbits. He does not recall any animal bites. What disease should be considered in the differential diagnosis?
Tularemia
What is the most significant predisposing factor to clostridium difficile-associated disease?
Antimicrobial therapy
