Microbiology Exam 50-Question Focus: Chapters 11 & 13

Vocabulary-style flashcards covering microbial infection, disease progression, portals of entry/exit, control methods, and antimicrobial agents based on BIO 205 Chapters 11 and 13.

Infection

A condition in which pathogenic microorganisms penetrate host defenses, enter the tissues, and multiply.

Disease

A pathologic state that results from the cumulative effects of infection and damages or disrupts tissues and organs; it is any deviation from health.

Infectious disease

Disruption of tissues or organs caused by microbes or their products.

Pathogen

A microbe whose relationship with its host is parasitic and results in infection and disease.

True pathogen

A pathogen capable of causing disease in healthy persons with normal immune systems.

Opportunistic pathogen

A pathogen that causes disease when the host's defenses are compromised or when it becomes established in a part of the body that is not natural to it.

Virulence

The degree of pathogenicity; it is indicated by a microbe's ability to establish itself in the host and cause damage.

Virulence factor

Any characteristic or structure of a microbe that contributes to toxin production or induces an injurious host response.

Five major steps of infection

1) Find a portal of entry, 2) attach firmly to host tissues, 3) survive host defenses, 4) cause damage/disease, and 5) exit the host.

Portal of entry

A characteristic route taken by a microbe to initiate infection, usually through skin or mucous membranes.

Skin portals of entry

Nicks, abrasions, and punctures.

Gastrointestinal tract portal of entry

Entry through food, drink, or other ingested substances, requiring adaptation to survive digestive enzymes and abrupt pH changes.

Respiratory portals of entry

The oral cavity, nasal cavity, and the continuous mucous membrane covering the upper respiratory tract, sinuses, and auditory tubes.

Urogenital portals of entry (STI)

Penis, external genitalia, vagina, cervix, and urethra.

Adhesion

The process by which microbes gain a more stable foothold on host tissues, depending on binding between specific molecules on the host and pathogen.

Quorum sensing

Chemical communication between nearby bacteria that is critical to the establishment of infection.

Phagocytes

White blood cells that engulf and destroy pathogens by means of enzymes and antimicrobial chemicals.

Sign

Objective evidence of disease noted by an observer; signs are more precise than symptoms.

Symptom

Subjective evidence of disease as sensed by the patient.

Syndrome

A disease identified or defined by a certain complex of signs and symptoms.

Inflammation

The earliest symptom of disease, according to the class PowerPoint.

Edema

Accumulation of fluid in afflicted tissue.

Leukocytosis

An increase in the level of white blood cells.

Leukopenia

A decrease in the level of white blood cells.

Septicemia

A general state in which microbes are multiplying in the blood and are present in large numbers.

Bacteremia

Small numbers of bacteria are present in the blood but are not necessarily multiplying.

Viremia

The presence of viruses in the blood, whether or not they are actively multiplying.

Portal of exit

An avenue for pathogens to exit the host.

Four general portals of exit

Secretion, excretion, discharge, and sloughed tissue.

Intestinal pathogen exit

Commonly through feces; helminths may release eggs and cysts through this route.

Urogenital pathogen exit

Vaginal discharge, semen, or urine.

Blood portal of exit

Removed or released through vascular puncture, often transmitted by blood-feeding animals like ticks and fleas.

TORCH

$T = \text{Toxoplasmosis}$; $O = \text{Other diseases (syphilis, coxsackievirus, varicella-zoster virus, AIDS, chlamydia)}$; $R = \text{Rubella}$; $C = \text{Cytomegalovirus}$; $H = \text{Herpes simplex virus}$.

TORCH complications

Spontaneous abortion, congenital abnormalities, brain damage, prematurity, and stillbirths.

Toxin

A specific chemical product of microbes, plants, and some animals that is poisonous to other organisms.

Exotoxin

A toxin secreted by a living bacterial cell into infected tissues.

Endotoxin

Lipopolysaccharide ($LPS$) shed from the outer membrane of gram-negative bacteria exclusively; it is not actively secreted.

Sterilization

The destruction of all microbial life; it destroys or removes all viable microorganisms, including viruses and bacterial endospores.

Disinfection

A physical process or chemical agent used to destroy vegetative pathogens but not bacterial endospores; used on inanimate objects.

Antisepsis

The application of chemical agents (antiseptics) to exposed body surfaces, wounds, and surgical incisions.

Decontamination (Sanitization)

A cleansing technique that mechanically removes microbes and debris and reduces contamination to safe levels.

Microbicidal agent

An agent that kills microorganisms.

Microbistatic agent

An agent that prevents microbes from multiplying but does not kill them.

Cellular targets of antimicrobial agents

The cell wall, the cell/cytoplasmic membrane, cellular synthetic processes ($DNA$ and $RNA$), and proteins.

Protein denaturation

Disruption of proteins that renders them nonfunctional by breaking bonds that maintain secondary and tertiary structure.

Moist heat

The most effective physical agent of microbial control, including hot water, boiling water, and steam from $60^{\circ}\text{C}$ to $135^{\circ}\text{C}$.

Thermal death point

The lowest temperature required to kill all microbes in a sample in $10\,\text{minutes}$.

Thermal death time

The shortest length of time required to kill all test microbes at a specified temperature.

Pasteurization

A moist-heat disinfection technique used on liquids to kill agents of infection and spoilage while retaining flavor.

Flash method pasteurization

$71.6^{\circ}\text{C}$ for $15\,\text{seconds}$.

Batch method pasteurization

$63^{\circ}\text{C}$ to $66^{\circ}\text{C}$ for $30\,\text{minutes}$.

Fungicide

An agent that kills fungal spores, hyphae, and yeasts.

Alcohols ($70\%$ to $95\%$)

Germicidal agents used for skin degerming and disinfecting medical equipment; efficacy is limited by evaporation.

Silver nitrate

Used as a topical germicide.

Silver sulfadiazine

Used for burn treatment.

Pure silver

Incorporated into catheters.

Colloidal silver

Used as a mild germicide.

Silver ions

Incorporated into hard surfaces and textiles.