114 finals

mamatai n lng tlga

Nystatin

Streptomyces noursei

Amphotericin B

Streptomyces nodosus

Natamycin

Streptomyces natalensis

Griseofulvin

Streptomyces griseofulvum

Rifampin/ Rifamycin B

Streptomyces mediterranei

Chloramphenicol

Streptomyces venezuelae

Cycloserine

Streptomyces capreolus; Streptomyces garyphalus

Plicamycin

Streptomyces tanashiensis; Streptomyces plicatus

Streptozocin

Streptomyces achromogenes

Pentostatin

Streptomyces antibioticus

Daptomycin

Streptomyces roseosporus

Streptomycin

Streptomyces griseus

Chlortetracycline

Streptomyces aureofaciens

Quinopristine / Dalfopristine

Streptomyces pristinaespiralis

Bleomycin

Streptomyces verticillus

Vancomycin

Streptomyces orientalis

Doxorubicin and Daunorubicin

Fermentation products of Streptomyces peucetius

Polymyxin B

Bacillus polymyxa

Bacitracin

Bacillus subtilis Tracy strain

Teicoplanin

Actinoplanes teichomyceticus

Stages in plaque development and cariogenesis

1. Pellicle formation

2. Bacteria and plaque formation

3. Acid formation and caries development

Degrees of dental caries

1. First-degree: initial lesion

2. Second-degree: Tooth destruction

3. Third-degree: Toothache

Pathogen enters GIT and multiplies

Infection

Ingestion of a preformed toxin

Intoxication

Three or more loose stools in 24-hour period

Diarrhea

Severe diarrhea with blood or mucus

Dysentery

Inflammation of the stomach and intestinal mucosa

Gastroenteritis

Endotoxin vs. Exotoxin

Endotoxin	Exotoxin
Common in G(-) bacteria Seen at the bacterial cell membrane. Composed of lipopolysaccharides Heat stable Not very toxic	Mostly gram(+) Synthesized in the cytoplasm, diffusable Composed of proteins Heat-labile Potent and toxic

Exotoxins and pyrogenic response

G(-) bacteria are engulfed by macrophages and are degraded → exotoxins are released and induce macrophage to produce cytokines IL-1 and TNF-𝝰 → signals hypothalamus to increase temperature and cause fever

heat-labile exotoxin internalized by the cell and binds to 60s ribosome subunit, causing damage to protein synthesis.

shiga toxin

DESCRIPTION	S/X
Plaque formation from food containing carbohydrates	Toothache

CONDITION	CAUSATIVE AGENT	TREATMENT
Dental Caries	Streptococcus mutans Streptococcus sobrinus Some Lactobacilli	Extraction Dental fillings

common name for Scradovia wiggseae

Early childhood carries

S/X

Inflammation of gums

CONDITION	CAUSATIVE AGENT	TREATMENT
Periodontal Disease	Porphyromonas sp.	For systemic infection: Chlorhexidine, doxycycline, minocycline, tetracycline For inflammation: Steroids

bleeding of gums

Gingivitis

bleeding with pus; loosening and loss of teeth

Periodontitis

Source: From custard, dairy, poultry (chicken sandwich!) or foods with high salt or sugar content

CONDITION	CAUSATIVE AGENT
Staphylococcal Enterotoxicosis	Staphylococcus aureus

DESCRIPTION	S/X
From fried rice, cooked meat, vegetables (Chinese vegan fried rice!)	Vomiting, diarrhea

CONDITION	CAUSATIVE AGENT
Bacillus cereus GE	Bacillus cereus

DESCRIPTION	S/X
From animal flesh (raw meat) and veggies	Acute abdominal pain

CONDITION	CAUSATIVE AGENT
Clostridium perfringens GE	Clostridium perfringens

Low MW, heat stable, usually from fried rice -> vomiting

Emetic toxin of B. cereus

High MW, heat-labile, usually from cooked meat and veg -> diarrhea

Diarrheal toxin of B. cereus

DESCRIPTION	S/X
Oral-oral or fecal-oral route; common with O blood type Aggravated by spicy and acidic food, stress and night time eating	Gastritis due to painful, open sores on the lining of the stomach and small intestine

CONDITION	CAUSATIVE AGENT	TREATMENT
Peptic Ulcer	Helicobacter pylori	Triple therapy 1. Omeprazole 2. Clarithromycin 3. Amoxicillin / Metronidazole 4. + Bismuth subsalicylate (if quadruple therapy)

DESCRIPTION	S/X
Fecal-oral and direct contact via shiga toxin Enters via M cells and cause inflammation in IL-1B Do not spread in bloodstream	Watery stool with occult blood and mucus Severe abdominal cramps Fever

CONDITION	CAUSATIVE AGENT	TREATMENT
Shigellosis	Shigella sp. (sonnei, dysenteriae, flexneri, boydii)	3rd gen cephalosporin (Tax) If AIDS px: fluoroquinolones

DESCRIPTION	S/X
From animal products (meat, milk, eggs), rodent feces From intestines/feces of pet reptiles Can spread to the blood stream -> cause septicemia	Diarrhea with blood and mucus Abdominal pain, fever N/V

CONDITION	CAUSATIVE AGENT	TREATMENT
Salmonellosis	Salmonella sp. (var. Paratyphi, hirschfeldii, typhimuium)	3rd gen cephalosporin or fluoroquinolones
	Arizona hinshawii

DESCRIPTION	S/X
From contaminated water and sewage system Most severe manifestation of salmonella	High fever, headache, malaise Rose spots

CONDITION	CAUSATIVE AGENT	TREATMENT
Typhoid fever	Salmonella sp. Var. typhi	3rd gen cephalosporin or fluoroquinolones

DESCRIPTION	S/X
From contaminated water and warm, alkaline, saline waters	Rice water stools Flaccid skin Sunken eyes

CONDITION	CAUSATIVE AGENT	TREATMENT
Cholera	Vibrio cholerae	Adults: doxycycline Children/Pregnant: Azithromycin ORS

DESCRIPTION	S/X
From coastal waters and raw fish, oysters and crustaceans	Watery stools (like cholera)

CONDITION	CAUSATIVE AGENT	TREATMENT
Vibriosis	Vibrio parahaemolyticus	Tetracycline Ciprofloxacin

DESCRIPTION	S/X
From cattle and contaminated food and water	Inflamed colon w/ blood) Damaged BV in kidneys

CONDITION	CAUSATIVE AGENT	TREATMENT
E. Coli GE	Escherichia coli	Triple therapy 1. Omeprazole 2. Clarithromycin 3. Amoxicillin / Metronidazole 4. + Bismuth subsalicylate (if quadruple therapy)

DESCRIPTION	S/X
From contaminated water and milk, contaminated meat and chicken Most common cause of bacterial GE Fecal oral or direct contact -> release cholera-like enterotoxin	Guillain-Barre syndrome (temporary paralysis)

CONDITION	CAUSATIVE AGENT	TREATMENT
Campylobacter GE	Campylobacter jejuni	Macrolides (azithromycin or erythromycin)

DESCRIPTION	S/X
From broad spectrum antibiotics Most common cause of nosocomial diarrhea Release of toxin a and B pseudomembranous appearance	Diarrhea, dysentery, pseudomembranous colitis

CONDITION	CAUSATIVE AGENT	TREATMENT
C. Difficile colitis	Clostridium difficile	Withdrawal of antibiotics Mid-moderate: Metronidazole Severe: Vancomycin

DESCRIPTION	S/X
From contaminated food, toys, baby bottles Most common cause of nosocomial diarrhea	Pseudo appendicitis syndrome

CONDITION	CAUSATIVE AGENT	TREATMENT
Yersiniosis	Yersinia enterocolitica, Pseudotuberculosis	For severe: doxy, genta, trimethoprim-sulfamethoxazole

Match the following:

A	B
Enterohemorrhagic EC	Infant diarrhea (profuse, watery)
Enteroaggregative EC	Shiga toxin, bloody diarrhea
Enterotoxigenic EC	Traveler’s diarrhea
Enteroinvasive EC	Watery diarrhea in aids px and kids
Enteropathogenic EC	With blood and pus

Enterohemorrhagic EC	Shiga toxin, bloody diarrhea
Enteroaggregative EC	Watery diarrhea in aids px and kids
Enterotoxigenic EC	Traveler’s diarrhea
Enteroinvasive EC	With blood and pus
Enteropathogenic EC	Infant diarrhea (profuse, watery)

GIT and its defenses

Mucus	Thick, fluid-like substance that provides mechanical protection to the intestinal surface and lining
Muscular walls	Has a continuous action of peristalsis that moves unwanted microorganisms out of the body
Saliva	Contain lysozyme and lactoferrin and also has a washing effect
Lysozyme	Breakdown the peptidoglycan component of bacterial cell wall
Lactoferrin	Sequesters iron which prevents growth and survival of bacteria
Stomach Fluid	Highly acidic which provides an extreme environment for the bacteria
Bile	Disrupt the cell membrane of bacteria
Secretory IgA	Protect adhesion of pathogens and their penetration into the intestinal barrier
Gut-Associated Lymphoid Tissue	Collection of immune cells in the GIT that give immunity to certain harmful microorganisms and produce IgA
Tonsils and Adenoids	Can be seen in the oral cavity and pharynx
Peyer’s patch	Can be seen in the small intestine
Appendix	A lymphoid tissue

upper GIT bacterial infections

1. dental caries

2. periodontal disease

lower GIT bacterial intoxications

1. staphylococcal food poisoning

2. b. cereus GE

3. c. perfringens GE

lower GIT bacterial infections

1. peptic ulcer

2. shigellosis

3. salmonellosis

4. typhoid fever

5. cholera

6. vibriosis

7. E. coli GE

8. Campylobacter GE

9. C. difficile colitis

10. yersiniosis

Neisseria gonorrhoeae

Theyer-Martin Agar

Clostridium or Bacteroides

Thioglycollate Medium

Vibrio cholarae

Thiosulfate-citrus-bile-salts-sucrose Agar

Corynebacterium diphtheriae

Loeffler’s Medium

Helicobacter pylori

Skirrow’s Medium

Mycobacterium spp.

Lowenstein-Jensen Medium

Bordetella pertussis

Gengou Agar

Leptospira spp.

Fletcher’s Media

Haemophilus influenzae

Chocolate Agar

use of chemical substances to treat various aspects of disease

Chemotherapy

produced by a microorganism in small amounts to inhibit another microorganism.

Antibiotic

 special group of chemotherapeutic agents that kill microbes

Antimicrobial

agents used to kill infectious or inhibit its spread (includes antiparasitics, anthelmintics, antiprotozoal agents)

Anti-infectives

4 Major Producers of Antimicrobials

Streptomyces & Bacillus – bacteria

Penicillin & Cephalosporium – molds

Most common producer of antimicrobials

Streptomyces

Goal of antimicrobial toxicity

Selective toxicity

• For critically ill px when we are not 100% what the causative agent is but we can infer what the most likely agent it is.

• Con: prone to resistance

• Broad spectrum antimicrobial agents are used.

empiric therapy

• Identified Etiologic pathogen and susceptibility

• Narrow spectrum

• Preferred. Less resistance, less cost for px

definitive therapy

Determines the susceptibility and resistance of bacteria to a particular antibacterial agent.

Kirby-Bauer Disk Diffusion Test

• Show how susceptible a series of organisms are to different antimicrobials.

• Annual summary of local antibiotic susceptibilities

• unit specific – can vary per hospitals

Antibiogram

arrange cephalosporins according to increasing spectrum

1st generation – narrow spectrum (more + cocci)

2nd generation – intermediate spectrum (less + cocci, better – bacilli)

• H. influenzae and E. aerogenes

3rd generation – broad spectrum (good + cocci, best – bacilli)

• H. influenzae and E. aerogenes

• Some enterobacteriaceae that do not produce ampC nor extended spectrum B-lactamase

4th generation – extended-spectrum (good + cocci, best – bacilli)

• Producers of amp C and ESBL

5th generation – extended-spectrum (Methicillin resistant staph. aureus)

• E. faecalis

5D of Antimicrobial Stewardship

1. Diagnosis

2. Drug

3. Duration

4. Dose

5. De-escalation

De-escalation Strategies

• Definitive therapy 

• Switch from IV to oral

Bacteriostatic drugs

Tetracyclines

Macrolides

Clindamycin

Chloramphenicol

Ethambutol

Linezolid

Sulfonamides (-cidal at high conc)

trimethoprim

Bactericidal drugs

Penicillins

Cephalosporins

Monobactams

Carbapenems

Other cell wall synth inhibitors

Rifampicin, isoniazid, pyrazinamide

Streptogramins

Aminoglycosides

Polymyxins

Lipopeptides

Fluoroquinolones

Sulfonamides + trimethoprim (bactericidal due to additive effects)

Cell wall synthesis inhibitors

Inhibits enolpyruvate transferase (1st wall synthesis is disrupted)

moa of fosfomycin trometamol

Cell wall synthesis inhibitors

Inhibits Alanine racemase and D-alanyl-D-alanine ligase (for incorporation of alanine to tetrapeptide formation)

MOA of cycloserine

Cell wall synthesis inhibitors

Inhibits dephosphorylate by acting on the lipid carrier that transfers the peptidoglycan unit.

MOA of bacitracin

Cell wall synthesis inhibitors

Bind to D-ala-D-ala terminus to prevent further attachments to the cell wall

MOA of vancomycin

Cell wall synthesis inhibitors

Inhibits transpeptidase

MOA of penicillin and cephalosporin

Cell wall membrane function

Using Ca2+, it generates energy to bind in between the phospholipid bilayer → creating a hole in the bilayer and a channel → depolarization and ion reflux. K ions exit the cell, causing an overall destruction to the cell membrane and integrity of the cell → lysis

MOA of Daptomycin

Protein synthesis inhibitors

Bind to 50s and inhibit formation of peptide bond

MOA of Chloramphenicol

Protein synthesis inhibitors

Interfere w/ attachment of tRNA and mRNA

MOA of tetracycline

Protein synthesis inhibitors

Change shape of 30s portion → incorrect code on mRNA

MOA of streptomycin

Nucleic acid synthesis inhibitor

Disrupts RNA synthesis.  Acts on RNA polymerase → distorted mRNA

MOA of rifampin

Nucleic acid synthesis inhibitor

Disrupts DNA synthesis.  Act against folate precursors.

MOA of Trimetoprim, Sulfonamides

Nucleic acid synthesis inhibitor

Destroy bond → destroy shape/integrity of the DNA, inhibiting reproduction of nucleic acids.

MOA of metronidazole

Nucleic acid synthesis inhibitor

Inhibit topoisomerase causing supercoiling

moa of Quinolones

Antimetabolites

Inhibits dihydrofolic acid

MOA of Sulfonamide

Antimetabolites

Inhibits dihydrofolate reductase

MOA of trimetoprim

categories of cell wall synthesis inhibitors

DRUG	ACTION
Beta-Lactam Antibiotics	Contains a beta-lactam rings Penicillins, Carbapenems, Cephalosporins, Monobactams
Polypeptide Antibiotics	Bacitracin, Vancomycin
Antimycobacterials	Isoniazid, ethambutol

categories of psi

30s	50s
Buy AT 30	S(C)eL at 50s
Aminoglycosides (streptomycin, gentamicin) Tetramycin	Streptogramin Chloramphenicol Clindamycin Linezolid Macrolides (Erythromycin)

categories of nucleic acid synthesis inhibitors

CATEGORY	DRUG
DNA-Dependent RNA polymerase inhibitors	Rifamycin	Rifampicin
DNA-gyrase Inhibitors	Quinolones (-flox)	Nalidixic acid Norfloxacin Ciprofloxacin Ofloxacin Levofloxacin Gatifloxacin

Selective and Differential Culture Media for Cultivation of Bacteria

CAUSATIVE AGENT	MEDIUM USED
Neisseria gonorrhoeae	Theyer-Martin Agar
Clostridium or Bacteroides	Thioglycollate Medium
Vibrio cholarae	Thiosulfate-citrus-bile-salts-sucrose Agar
Corynebacterium diphtheriae	Loeffler’s Medium
Helicobacter pylori	Skirrow’s Medium
Mycobacterium spp.	Lowenstein-Jensen Medium
Bordetella pertussis	Gengou Agar
Leptospira spp.	Fletcher’s Media
Haemophilus influenzae	Chocolate Agar

1st gen cephalosporins

Cephalotin	1st gen	narrow spectrum (more + cocci)
Cephapirin
Cefazolin
Cefadroxil
Cephalexin
Cephradine