Clinical and Environmental Importance of Enterobacteriaceae

Enterobacteriaceae

Family of gram-negative bacteria, includes major pathogens.

Clinical Importance

Causes UTIs, pneumonia, gastroenteritis, sepsis.

Antibiotic-resistant strains

Includes ESBL-producing E. coli and CRE.

Foodborne illnesses

Caused by Salmonella, Shigella, E. coli O157:H7.

Environmental Importance

Found in soil, water, plants, and intestines.

Nitrogen cycle

Process involving nitrogen transformation by bacteria.

Coliforms

Lactose fermenting bacteria, indicators of fecal contamination.

Non-coliforms

Bacteria that do not ferment lactose.

Examples of Coliforms

Includes Escherichia, Enterobacter, Serratia, Citrobacter.

Examples of Non-coliforms

Includes Salmonella, Shigella, Yersinia.

Selective media

Inhibits growth of unwanted bacteria.

Differential media

Distinguishes between different types of bacteria.

Eosin Methylene Blue (EMB) Agar

Selective for gram-negative, differentiates lactose fermenters.

Positive EMB result

Media turns dark purple, black, or iridescent green.

Phenol Red Broth

Differential medium for carbohydrate fermentation and gas.

Durham tube

Used to detect gas production in fermentation.

Citrate Test

Detects citrate permease and alkaline byproducts.

Bromothymol blue

pH indicator used in citrate test.

Positive Citrate Test

Media turns blue indicating alkaline reaction.

SIM Media

Used for sulfide, indole, and motility tests.

Sulfide test

Detects hydrogen sulfide production in SIM.

Indole test

Detects indole production from tryptophan.

Motility test

Determines bacterial motility in SIM media.

Sulfur Reduction

Test for sulfate reduction using thiosulfate.

Indole Production

Tests tryptophan conversion to indole with Kovak's reagent.

Motility

Assesses bacterial movement via stab line haziness.

Thiosulfate

Substrate for sulfate reduction in sulfur test.

Kovak's Reagent

Indicator for indole production test.

Positive Result

Indicates successful reaction in biochemical tests.

Negative Result

Indicates failure of reaction in biochemical tests.

Neglected Tropical Diseases (NTDs)

Communicable diseases prevalent in tropical/subtropical regions.

Eukaryotic Pathogens

Pathogens including fungi, protozoa, and helminths.

Fungal Infections

Includes chromoblastomycosis and mycetoma.

Protozoa

Single-celled organisms, no cell wall, irregular shapes.

Helminths

Multicellular worms, may produce eggs and larvae.

Opisthokonta

Group including fungi and humans, sharing cellular similarities.

Amoeboid Morphology

Movement via pseudopodia, arm-like cell extensions.

Ciliated Morphology

Movement using cilia, short hair-like structures.

Flagellated Morphology

Movement via flagella, long whip-like structures.

Apicomplexan Morphology

No visible movement structures, internal movement mechanisms.

Trophozoite Stage

Active, motile form of protozoa.

Cyst Stage

Protective form of protozoa under harsh conditions.

Protozoan Life Cycle

Complex life cycle involving trophozoite and cyst stages.

Flatworms

Type of helminth with flat morphology.

Roundworms

Type of helminth with cylindrical shape.

Flukes

Type of helminth often with complex life cycles.

Cestodes

Type of flatworm; includes tapeworms.

Trematodes

Flat, leaf-shaped worms; require snails as hosts.

Nematodes

Cylindrical, unsegmented worms; complete digestive tract.

Intermediate host

Hosts required for immature helminth life stages.

Definitive host

Hosts supporting adult, sexually mature helminths.

Fecal/oral transmission

Ingesting contaminated substances with eggs or larvae.

Predator/prey transmission

Ingesting infected animals.

Transdermal transmission

Infection through skin penetration by larvae.

Vector transmission

Infection via insect bites or contact.

Helminth life cycle

Includes egg, larvae, and adult stages.

Bactericidal

Kills bacteria, leading to cell death.

Bacteriostatic

Inhibits bacterial growth; bacteria can survive.

Chemical control strategies

Use substances like bleach to inhibit microbes.

Physical control strategies

Destroy microbes using heat or radiation.

Mechanical control strategies

Physically remove microbes via scrubbing or filtration.

UV radiation

Damages bacterial DNA, preventing replication.

Endospore-forming bacteria

More resistant to UV due to protective layers.

Non-endospore-forming bacteria

Highly sensitive to UV; quick death upon exposure.

Thymine dimers

DNA damage caused by UV light.

Antimicrobial drug targets

Six classes affecting bacterial growth.

Adult worm

Mature stage that reproduces and produces eggs.

Microscopy of eggs

Used for diagnosing helminth infections.

Cell Wall

Structure preventing cell bursting under osmotic pressure.

Proteins

Molecules that perform various cellular functions.

DNA/RNA

Genetic material responsible for replication.

Membrane

Barrier controlling substance entry and exit.

Metabolism

Chemical processes for energy and growth.

Attachment

Process allowing pathogens to infect host cells.

Plate Sensitivity Test

Method to assess bacterial antibiotic resistance.

Zone of Inhibition

Area around antibiotic with no bacterial growth.

Antibiotic Sensitivity Table

Chart to classify bacteria as resistant or sensitive.

Gram-Positive Bacteria

Bacteria with thick peptidoglycan, sensitive to antibiotics.

Gram-Negative Bacteria

Bacteria with outer membrane, resistant to many antibiotics.

Lysozyme

Enzyme targeting peptidoglycan in bacterial cell walls.

Innate Immunity

Non-specific defense mechanisms present at birth.

Adaptive Immunity

Specific immune response developed after exposure.

Antibody

Protein produced by B cells to neutralize antigens.

Antigen

Foreign substance triggering an immune response.

Effector Functions of Antibodies

Actions antibodies take to eliminate pathogens.

Neutralization

Blocking pathogen binding to host cells.

Opsonization

Tagging pathogens for destruction by immune cells.

Complement Activation

Initiating a cascade to kill bacteria.

Immunotherapy

Treatment using the immune system to combat diseases.

Monoclonal Antibodies

Lab-made antibodies targeting specific disease markers.

ELISA

Test for detecting antibodies or antigens in samples.

Anti-HIV Antibody

Antibody produced in response to HIV infection.

Substrate

Substance reacting with enzyme to indicate presence.