(M) Lesson 7.2: Gram Positive and Gram Negative Cocci Flashcards by Kchianna Lauren Coronel

Q

Gram positive cocci in clusters
Non-motile
Non-sporeformer
A facultative anaerobe
Medically important species (pathogenic and are routinely isolated in the lab

A

Staphylococcus

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Q

Important biochemical property of Staphylococcus?

A

Catalase positive

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Q

What are the three medically important species of Staphylococcus?

A

Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus saphrophyticus

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Q

Give the result with respect to Staphylococcus aureus.

Catalase

A

Positive

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Q

Give the result with respect to Staphylococcus aureus.

Coagulase

A

Positive

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Q

Give the result with respect to Staphylococcus aureus.

Salt (halo) (7.5 to 10% NaCl)

A

Tolerant

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Q

Give the result with respect to Staphylococcus aureus.

Mannitol

A

Fermenter

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Q

Give the result with respect to Staphylococcus aureus.

DNAse

A

Positive

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Q

Give the result with respect to Staphylococcus aureus.

Nitrate and Voges Proskauer (VP)

A

Positive

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Q

Give the result with respect to Staphylococcus aureus.

Gelatin

A

Positive

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Q

Give the result with respect to Staphylococcus aureus.

PYR

A

Negative

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Q

Give the result with respect to Staphylococcus aureus.

BAP

A

Yellow-orange colony

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Q

____, ____, and ____ are biochemically important in gram-negative organisms.

A

Nitrate and VP
Gelatin
PYR

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Q

____, ____, ____, and ____ are mainly used for identification.

A

Catalase
Coagulase
MSA
DNAse

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Q

Having lipochrome results in?

A

Yellow-orange colony

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Q

Beta-hemolysis results in?

A

Yellow halo around the growth

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Q

What is the distinct smell of a pure colony of Staphylococcus?

A

Unwashed clothes or socks

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Q

Transmission routes from person to person happens through?

A

Sneezing
Formites
Surgical wounds
Infected patients
Food

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Q

What are the virulence factors of Staphylococcus?

A

Cell-associated factors
Extracellular

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Q

Virulence Factors

Already attached to the bacterial membrane, cytoplasm, or cell wall
Ag in serology for identification
Contributes to pathogenicity (how it can infect)

A

Cell-Associated Factors

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Q

Virulence Factors

Released by bacterium depending on the environment
Enzymes or toxins
For protection

A

Extracellular

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Q

Cell-Associated Factors

Most important in Staphylococcus aureus

A

Protein A

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Q

Extracellular (Enzymes)

Familiarize yourself with the different enzymes.

A

Catalase
Free coagulase
Lipase
Hyaluronidase
B-lactamase
Staphylokinase
Proteinases

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Q

Extracellular (Enzymes)

By all Staphylococcus

A

Catalase

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# Extracellular (Enzymes) * By Staphylococcus aureus * Protection from immune system

Free coagulase

# Extracellular (Enzymes) * Spreading factor * Not unique to Staphylococcus aureus * Infection spreads from one site to another

Hyaluronidase

# Extracellular (Enzymes) * Resistance to penicillin (and other antibiotics)

B-lactamase

# Extracellular (Enzymes) * Also known as fibrinolysin * Lyses coagulase * To undergo proper metabolism

Staphylokinase

# Endotoxin or Exotoxin? * By gram-negative organisms * During cell death * Less poisonous *(lipopolysaccharide)* * Non-specific tissue affinity

Endotoxin

# Endotoxin or Exotoxin? * By gram-positive organisms * During life cycle * More poisonous *(active)* * Specific tissue affinity * More immunogenic

Exotoxin

Staphylococcus releases what type of toxins?

Exotoxins

# Extracellular (Toxins) What are the different types of toxins within Staphylococcus?

1. Cytolytic Toxins *(Hemolysin alpha, betta gamma, and delta + Leucocidin)* 2. Enterotoxin A-F 3. Toxic Shock Syndrom Toxin-1 *(TSST-1)* 4. Exfoliative

# Determine the type of toxins. * Targets cells like RBCs and WBCs

Cytolytic toxins

# Determine the type of toxins *(cytolytic toxins).* * Targets the RBC cells specifically

Hemolysin

# Determine the type of toxins *(cytolytic toxins).* * Used for Staphylococcus aureus

Hemolysin beta

# Determine the type of toxins *(cytolytic toxins).* * Targets WBCs cells specifically

Leucocidin

# Extracellular (Toxins) * Targets the intestine * Heat-stable at 60°C for 10 minutes

Enterotoxin A-F

# Extracellular (Toxins) * Targets the nephrons *(kidneys)*

Toxic Shock Syndrome Toxin-1

# Extracellular (Toxins) * Also known as epidermolytic toxin * Targets the skin

Exfoliative

Infections are caused by ____ or ____

1. By a bacteria itself 2. By an enzyme from bacteria as its virulence factor

This is due to toxins released by bacteria.

Intoxication

T or F: Patient may not react to the bacteria itself.

T

# Skin and Soft Tissue Infections * Follicle infection * **Site of Origin:** Hair follicles

Folliculitis

# Skin and Soft Tissue Infections * Progression of untreated folliculitis * Spread around the area of the follicle

Furuncle (Boil)

# Skin and Soft Tissue Infections * Spread to other areas

Carbuncle

# Skin and Soft Tissue Infections * Inflammation of the upper or lower eyelids

Styes

# Skin and Soft Tissue Infections * Starts as an untreated wound infection

Abscess

# Skin and Soft Tissue Infections * Staphylococcus aureus is the top causative agent regardless of morphology

Wound Infection

# Skin and Soft Tissue Infections * Painful crusts around the facial area

Impetigo

# Skin and Soft Tissue Infections * Nail infection from equipment used in nail care * Either toes or hands

Paronychia

# Skin and Soft Tissue Infections * Inflammation of cellulites

Cellulitis

# Name the affected system. * Osteomyelitis *(inflamed bone metaphysis)* * Arthritis * Bursitis * Pyomyositis

Musculoskeletal

# Name the affected system. * Tonsilitis * Pharyngitis * Sinusitis * Otitis * Bronchopneumonia * Lung abscess * Empyema * Pneuomonia *(rare)*

Respiratory

# Name the affected system. * Abscess * Meningitis * Intracranial thrombophlebitis

Central Nervous System

# Name the affected system. * Bacteremia * Septicemia * Pyemia * Endocarditis

Endovascular

# Name the affected system. * Urinary Tract Infection

Urinary

# Name the affected system. * Hospital-acquired

Nocosomial infection

Diseases caused by the bacterial exotoxin which are produced either in the infected host or performed in vitro.

Intoxications

What are the three types of intoxications?

1. Gastroenterititis *(Food Poisoning)* 2. Toxic Shock Syndrome 3. Staphylococcal Scalded Skin Syndrome

# Name the type of intoxication. * Occurs 1 to 8 hours after ingesting toxin * Manifestations include nausea, abdominal pain, vomiting followed by diarrhea and with no fever * Caused by **Enterotoxins A-F** preformed in food

Gastroenteretitis *(Food Poisoning)*

# Name the type of intoxication. * Manifestations include **abrupt** high fever, vomiting, diarrhea, myaligias, scarlantiniform rash, hypertension, and severe case of cardiac or renal failure * Caused by **TSST-1** * Requires immediate treatment

Toxic Shock Syndrome

# Name the type of intoxication. * Caused by **exfoliative toxin** * Common in children

Staphylococcal Scalded Skin Syndrome

We should collect specimen for treatment based on?

The type of infection

# Name the specimen to be collected based on type of infection. Wound infection from a suppurative lesion

Pus

# Name the specimen to be collected based on type of infection. Respiratory infection

Sputum

# Name the specimen to be collected based on type of infection. Bacteremia and septicemia

Blood

# Name the specimen to be collected based on type of infection. Food poisoning

Feces, vomit, remains of suspected food

# Name the specimen to be collected based on type of infection. Detection of carriers

Nasal swab

T or F: Carriers harbor the bacteria that show most if not all the symptoms.

F (do not show any symptom)

Staphylococcus aureus is highly susceptible to ____

Beta-lactam drugs like methicillin, nafcillin, oxacillin, and cloxacillin

T or F: Staphylococcus aureus can be resistant to methicillin.

T

Methicillin-resistant Staphylococcus aureus (MRSA) is challenging to treat because?

Methicillin is already a **high-level drug**

MRSA due to ____ is commonly resistant to antibiotics except vancomycin and fusidic acid.

Changes in major penicillin-binding proteins

T or F: Vancomycin and fusidic acid are usually given in low dosages as a last resort.

F (high dosages)

Nasal colonization in carriers can be treated with ____

Topical mupirocin

* A serological test * Rapid test * Coagulase test

BACTiStaph

* Normal flora of the skin and mucus membrane * Predominance indicates infection * Most common cause of CSF shunt infection * Infections are related to intravenous catheters and prosthetic implants

Staphylococcus epidermidis

* Biochemically negative for coagulas and susceptible for novobiocin

Staphylococcus epidermidis

T or F: If normal flora leaves its natural habitat, it may cause infections.

T

Infection due to Staphylococcus epidermidis leaving normal flora usually occurs with what two procedures?

1. Venipuncture 2. Undergo shunt *(catheter inserted in the body)*

This happens with patients with renal failure who are undergoing peritoneal dialysis through an indwelling catheter.

Peritonitis

* Medically important cause of UTI *(second most common causative agent)* in sexually active young women * Biochemically negative for coagulase and resistant to novobiocin

Staphylococcus saprophyticus

Most common causative agent of UTI?

Escherichia coli