Microbiology- studyguide

Coagulase

An enzyme produced by certain bacteria that coagulates blood plasma.

S. aureus

A gram-positive cocci bacterium known for producing various toxins and causing a range of infections.

MRSA

Methicillin-resistant Staphylococcus aureus; a strain of S. aureus resistant to methicillin.

N. gonorrhoeae

A gram-negative cocci bacterium that causes the sexually transmitted infection gonorrhea.

Streptococcus pyogenes

A beta-hemolytic streptococcus that produces toxins and causes diseases like strep throat and rheumatic fever.

Bacillus cereus

A gram-positive rod bacterium that can cause food poisoning.

Botulism

A severe illness caused by the toxin produced by Clostridium botulinum, often linked to improperly canned foods.

Bacillus anthracis

The bacterium that causes anthrax, characterized by a polypeptide capsule and exotoxins.

C. perfringens

A gram-positive rod bacterium responsible for gas gangrene.

Clostridium tetani

The bacterium that causes tetanus, characterized by a neurotoxin that leads to muscle paralysis.

C. difficile

A bacterium that causes antibiotic-associated diarrhea and colitis.

Mycobacterium tuberculosis

The bacterium that causes tuberculosis, known for its slow growth and acid-fast characteristics.

Hemagglutinin

A glycoprotein found on the surface of influenza viruses that allows them to bind to host cells.

What are the enzymes of S. aureus?

coagulase, lipase, penicillinase

Antigen-presenting cells

Cells that process and present antigens to T-cells, crucial for immune response.

Plasmids

Small, circular DNA molecules within bacteria that can carry genes for antibiotic resistance.

Endotoxin

A toxic component of the outer membrane of certain bacteria that can trigger inflammation.

Exotoxin

Toxins secreted by bacteria that can cause damage to the host by targeting specific cells.

Nosocomial infections

Infections acquired in a hospital setting, often resistant to common treatments.

What is coagulase?

coagulates (clots) blood plasma

How does botulism happen?

improper canning or preservation of food, leading to the growth of Bacillus botulinum bacteria.

How do you treat botulism?

Administer antitoxin & penicillin

What are the 3 types of Bacillus anthracis?

Cutaneous, Pulmonary, Gastrointestinal

How do you treat for Bacillus anthracis (anthrax)?

Administer antibiotics such as ciprofloxacin or doxycycline, and potentially use antitoxins; BioThrax with annual boosters

What is unique about the cell wall of Mycobacterium tuberculosis, and how does it contribute to its virulence?

The bacterium is characterized by slow growth and acid-fast characteristics due to a waxy coating (cord factor).

Mycosis

A fungal infection in animals that can affect various organs.

What is a cord factor?

a waxy coat that helps the bacteria stick together in rope-like structures and contributes to its virulence by protecting it from the immune system.

What is the virulence factors of M. Tuberculosis?

Complex waxes & cord factors that prevent destruction by lysosomes & macrophages

What is the other name for Myobacterium leprae?

Hansen’s Disease

What are the stages of TB?

Infection, Latent TB, Secondary/Reactivation, & Disseminated (Extra pulmonary) TB

What are the factors that can cause TB?

Inadequate nutrition, debilitated weakening of immune system, poor access to medical care, lung damage, genetics

What is the name of the bluish-green pigment of Pseudomonas aeruginosa?

Pyocyanin

Nosocomical infection

hospital/healthcare associated infections (HAI); infections acquired during medical treatment/procedures.

Brucellosis

undulant (rising & falling) fever

What is the danger of the Brucella species when it is not fatal?

it can be aerosolized, leading to respiratory infections for prolonged periods

What are the two spike proteins in influenza virus?

Hemagglutinin & Neuraminidase

What are the 6 types of E. coli?

Eterohemorrhagic (EHEC), Enterotoxigenic (ETEC), Enteroinvasive (EIEC), Enteropathogenic, Enteroaggregative, Diffusely adherent (DAEC)

What is 0157:H7?

foodborne illness from fast food (under cooked beef & unpasturized milk)

What is typhoid fever?

A bacterial infection caused by Salmonella typhi, leading to high fever, abdominal pain, and gastrointestinal symptoms; “Typhoid Mary”: unclean hands

What are the 6 subspecies of Salmonella enterica?

Enterica, Salamae, Arizonae, Diarizonae, Houtenae, Indica

What is the virulence factor of Yersinia pestis?

capsule & envelope proteins protect against phagocytes & intercellular growth

What is the vector of Yersinia pestis?

flea; bacteria in the flea’s gut causes coagulase of the blood thus blocking the esophagus that in turns causes the flea to be ravenous and bite more frequently, increasing transmission to hosts.

Why is Haemophilus referred to as “blood loving” and what growth factors does it require in culturing?

Considered “blood-loving” because it needs components found in blood to grow such as Hemin (factor X) & nicotinamide adenine dinucleotide (NAD; Factor V)

Blood Agar

nutrient-rich medium to support growth of a wide range of microorganisms, particularly fastidious (streptococci)

Spirochetes

helical & gram negative

Endoflagella

flexing propels cells by rotating & crawling motions

What are the stages of Syphilis?

Primary, secondary, latent, and tertiary

What tests are done to detect Syphilis?

Serological tests, dark-field microscopy, blood tests, DNA analysis of tissues

What is the vector for Borrelia hermsii and what is relapsing fever?

Ticks and a cycle of infection and returning of fever and symptoms

What is the vector for B. burgdori (lyme disease & Rickettsia rickettsii?

Tick bites

How does Vibrio cholerae (Cholera) spread?

ingestion of contaminated food/water

How does H. pylori cause gastric ulcers?

Produces urease → converts urea to ammonium & bicarbonate → neutralizes acid, damages mucosa → gastric ulcers.

What is fungal dimorphism?

Ability to morph into two forms cells: hyphal cells (molds) & yeast cells; Molds grow in 30*C, Yeast grow in 37*C

What is fungal morphological identification?

A method to identify fungi based on their physical characteristics, such as structure, color, and type of growth form.

what is fungal opportunistic and true pathogens?

Opportunistic: organisms cause disease only in immunocompromised hosts; True pathogens: capable of causing disease in healthy individuals.

what are the general characteristics of viruses?

Acellular that only replicate within a host cell. DNA/RNA & surrounded by a protein coat and host-specific.

Nucleic acid in viruses

viral genome; DNA or RNA; can be double or single stranded

Capsid

protein coat encloses & protects nucleic acid

What are the types of capsids?

Helical, Icosahedral, Envelope

What is a helical capsid?

spiral tube of protein coils around genetic material

What is a iscosahedral capsid?

Spherical structure of proteins (capsomeres) to protect genetic material; may have an envelope

Simple viral structure

either helical or icosahedral capsid

Complex viral structure

have both helical & icosahedral capsid

What are the steps in viral multiplication?

Adsorption (attachment), penetration, replication, assembly, maturation, lysis & release.

What is the different between the lytic and lysogenic cycle?

The lytic cycle destroys the host cell immediately, while the lysogenic cycle integrates viral DNA into the host's genome, allowing replication without killing the host.

How are viruses cultured & identified?

In vitro & In vivo; electron microscope, serological tests, PCR (polymerase chain reaction)

In vitro

controlled outside living organisms (tubes & petri dishes)

In vivo

studies on living organisms (bird embryos & live animals)

What are antigenic shifts and drifts?

Shift: a gene/RNA strand substituted with a gene or strand from another influenza virus from a different animal host; Drift: constant mutation

Prions

misfolded proteins with no nucleic acid & resistant to sterilization techniques (causes neurodegenerative diseases like Creutzfeldt-Jakob, mad cow, scrapie, wasting disease)

why is pox virus different from other viruses?

Replicates in cytoplasm of the host cell, unlike most viruses that replicate in nucleus. Also has a complex structure & can cause diseases such as smallpox.

How did vaccination contribute to the eradication of the smallpox virus?

Vaccination developed by Edward Jenner from cow pox provided immunity against smallpox, leading to widespread inoculation and ultimately the disease's eradication.

HSV1 (Herpes Simplex Virus Type 1)

orally transmitted virus causing cold sores and facial lesions; early childhood

HSV2 (Herpes Simplex Virus Type 2)

sexually transmitted virus causing genital herpes; 14-29 yrs

How is Hepititis B different from Hepititis A & C?

Hep B: sexually transmitted, Hep A: contaminated food, Hep C: blood

What are the clinical phases of rabies?

Prodromal, Furious, Paralytic, Coma → Death

What is an arbovirus and what are some examples?

Viruses transmitted by arthropods like mosquitoes and ticks. Ex: West Nile virus, Zika virus, and dengue virus.

What is the process of reverse transcriptase of HIV/AIDS?

HIV enzyme converts RNA into DNA → enters host cell nucleus → Host cell replicates HIV protein → more HIV cells that are dormant/noninfectious (latent)

What are the stages of AIDS?

Acute infection, Clinical latency, AIDS

Resident flora

microbes that stay; new “neighbors”

Transient flora

microbes that don’t stay long; transport/transition

Virulence factor

characteristic/structure that causes disease

What are the patterns of human diseases?

Localized, Systemic, Focal, Mixed, Primary & Secondary infections, Chronic & Acute, Direct & indirect contact

Localized infection

microbes enter body & remain on specific tissue

Systemic infection

spread to several sites & tissue fluids through the bloodstream

Focal infection

infection that begins as a localized infection but then spreads to other areas of the body.

Mixed infection

several microbes grow at the same time of infection site

Primary infection

initial infection

Secondary infection

following infection by a different microbe

Acute infection

comes rapidly, severe but short lived effects

Chronic infection

progress & persists for a long time

Direct contact

physical contact or fine aerosol droplets

Indirect contact

passes from infected → intermediate conveyor → new host

Signs

objective evidence noted by observer

Symptoms

subjective evidence sensed by patient

What are the body’s first line of defense?

Physical and chemical barriers (skin, mucous membranes, tears, stomach acid, flushing effect)

What are the types of blood cells?

Granulocytes, Neutrophils, Eosinophils, Basophils, Monocytes, Macrophages, Dendritic Lymphocytes, Erythrocytes (RBCs), Platelets

Specificity

antibodies produced & function against antigen that was made for

Memory

Lymphocytes (B&T-cells) programmed to recall first encounter with an antigen & respond quickly to new encounters

Antigen

any foreign substance that causes the immune system to respond