Microbiology: Identifying Bacterial Colonies

Helpful Microbiology Tips

• Pray before reviewing and taking the test
• Determine if the sample is gram-positive or gram-negative and if it contains cocci or bacilli
• Check if it is under aerobic or anaerobic conditions
• Focus on the characteristics given, such as Bull's eye colonies in Yersinia enterolitica
• If unsure, look at the test provided and identify the disease given
• Never forget the basics

Colonies

• Staphylococcus aureus: Pinhead colonies on BAP, jet-like colonies on tellurite agar/Vogel Johnson medium.
• Streptococcus: Pinpoint colonies.
• Streptococcus agalactiae & Clostridium perfringens: Arrowhead colonies with a zone of beta hemolysis; can also have a bowtie appearance.
• Streptococcus pneumoniae: Mucoid flat colonies with an appearance of depressed center in young colonies. Fully developed colonies have a dome shape (24 hrs), whereas older colonies will look like a nail head/crater
• Moraxella catarrhalis: Honey puck colonies.
• Corynebacterium: Club shaped forms Chinese Characters and palisades.
• Corynebacterium diphtheriae: bull's neck.
• Bordetella burgdorferi: Bull's eyerash.
• Yersinia enterolitica: Bull's eye colonies on CIN.
• Yersinia pestis: Safety pin appearance.
• Acinetobacter: Gummy colonies

Resemblances

• Moraxella catarrhalis resembles Neisseria.
• Streptococcal erysipelas resembles Streptococcus pyogenes.

Hemolytic Reactions

• Gamma Hemolytic bacteria:
  • Staphylococcus epidermidis
  • Staphylococcus saprophyticus
  • Micrococcus
  • Moraxella
• Beta Hemolytic bacteria:
  • Bacillus cereus
  • Clostridium botulinum

Common Organisms on Agar

• BAP (Blood Agar Plate):
  • Staphylococcus (beta-hemolytic)
  • Group A Streptococcus (Streptococcus pyogenes: is the best isolated)
  • Group B Streptococcus (Streptococcus agalactiae)
  • Streptococcus pneumoniae
  • Neisseria (room temperature)
  • Bacillus cereus
  • Bacillus subtilis
  • Clostridium perfringens (double zone/target hemolysis)
• CCFA:
  • Clostridium difficile
• Tomato Juice Agar:
  • Lactobacillus only

Gram-Positive Cocci (Aerobes)

• These form the SMS Cluster consisting of Staphylococcus, Micrococcus, and Streptococcus.
• Micrococci are arranged in tetrads. The cluster is also used to describe how the cocci join together

Gram-Positive Cocci (Anaerobes)

• They're the "Peptos" including Peptococcus and Peptostreptococcus

Gram-Negative Cocci (Aerobes)

• Neisseria
• Branhamella (Moraxella)

Gram-Negative Cocci (Anaerobes)

• Veilonella

Gram-Positive Bacilli (Aerobes)

• "MYBLENC": Mycobacteria, Bacillus, Listeria, Erysipelothrix, Nocardia, Corynebacterium

Gram-Positive Bacilli (Anaerobes)

• "CAP": Clostridium

Additional Tests/Reagents

• Furoxone-Tween 80 Oil Red Agar
• CAP
• Egg Yolk Agar: identifies Clostridium (Clostridium perfringens) due to lipase and lecithinase activity
• Oxidase test -Modified Oxidase test: Presumptive Test for Micrococci
• Bile Esculin Test:
  • Presumptive test
• Catalase Test
  • Staphylococcus (+),
  • Micrococci (+),
  • Streptococcus (-)
• Slide Coagulase:
  • CLOT (+,-)
• Tube Coagulase
  • Free bound coagulase -Reagent: Rabbit plasma (EDTA tube)
• Hyaluronidase/Lipase
  • Skin infections + T-Factor or Duran-Raynal Factor.
• N. gonorrheae

Gram Stain and Factors

• Pili:
  • Promotes attachment to host cells.
• Lipopolysaccharide:
  • Source of endotoxin.
  • Present in Por B ONLY (outer membrane protein)
  • Affects antibody formation.

Virulence Factors of Neisseria meningitidis

• Capsule
  • Enables organisms to resist phagocytosis.
• Pili
  • Promotes attachment
• Endotoxin -Causes petechia formation and DIC.
• IgA Protease -Important in pathogenesis and antibody found in mucous membranes
• Present in serotypes A & B.

Further Information

• Wet mount and hanging drop for Listeria monocytogenes. Presumptive Test for it being this
• Mouse Neutralization Test: Definitive ID Test for Clostridium botulinum
• "Whiff" test for Gardnerella vaginalis: Presumptive DX.

Streptococcus pyogenes Characteristics

• Hyaluronidase:
  • Spreading factor.
• Streptokinase:
  • Fibrinolysin
  • Causes lyse blood clots
  • Allows spread of infection
• Virulence Factor
  • Group C Strep, Major
• Protein F
  • Enhances attachment of epithelial cells
• Streptodornase/DNase
  • Group of 4 antigenic enzymes (A, B, C, and D)

Diseases Associated with Microorganisms

• Catheter-related infections: Staphylococcus lugdunensis
• Indwelling Catheter: Staphlyococcus saprophyticus
• Prosthetic Heart Valve Infection: Staphylococcus epidermidis and Corynebacterium jeikeium
• Leading cause of Neonatal Sepsis: Staphlyococcus lugdenensis
• Streptococcus agalactiae
• Eye infection in heroin addicts: Bacillus subtilis
• Associated with malignancies: C. septicum
• Most common in Sexually Active Young Women: Staphlyococcus saprophyticus
• Nosocomial UTI: Enterococci
• #1 cause of UTI- Gram (-) sepsis: Chlamydia urelyticum
• #2 cause of UTI*: E. coli
• Most common cause of UTI in human: Proteus, UPEC

Colon Cancer

• Enterococci
• Marker for Colon Cancer: Streptococcus bovis - Seen in PBS

Colon Cancer

• Streptococcus pyogenes -Edwardsiella, only human pathogen in the Enterobacteriacae

Animal Pathogen

• Group C Streptococci
• Listeria monocytogenes
• Corynebacterium pseudotuberculosis

Animal Abortions

• Campylobacter fetus

Cat Bites

• Pasturella multocida

Cat Scratch

• Bartonella

Rat Bite Fever/Haverhill Fever

• Streptobacillus monoliformis

Undulant/Malta Fever

• Brucella

Rabbit/Ohara/Market Man's Fever/Tularemia

• Francisella tularensis

Insect Pathogen

• Bacillus thurigiensis

Scarlet Fever

• Streptococcus pyogenes

Dental Carries and Dental Plaque

• Streptococcus mutans

*#1 cause of STI

• Gonorrhea*

Others: Opthalmia neonatorum

*#1 cause of neonatal meningitis

- ***Streptococcus Agalactiae***

*#1 Cause of Adult Bacterial Meningitis

• Streptococcus pneumoniae

*#1 Cause if Gastroenteritis Worldwide

• Campylobacter

*#1 Neutrophil Function Occupations

• Pseudomonas

*#2 Neutrophil Function Occupations

• Acinetobacter

*#2 Cause Of Neonatal Meningitis

• Escherichia coli

*#3 Bacterial Meningitis

• Haemophilus influenzae

Other Cause of Bacterial Meningitis

-Neisseria Meningitis

Meningococcemia

• • Meningitis in the blood
• Very Fatal
• Neisseria Meningitidis

Waterhouse Friedrichsen Syndrome

-Severe Form of Meningococcemia

• Neisseria Meningitidis

Other Types Of Meningitis

Staphlyococcus Agalactiae Neocates

• Haemophilus Influenzae Meningitis in children younger 5
• Neisseria Meningitis Under 5-29 yr olds Meningitis In ->>29 yr olds

Other Diseases:

• Erysipelothrix rusiopathiae: Erysipeloid ("Butcher's cut"; "Diamond cut") -a localized skin infection and an occupational hazard.
• Corynebacterium minutissimum: Erythrasma
• Streptococcus pyogenes: Erythema (area of redness in cellulitis)
• Streptococcus pyogenes: Erysipelas (painful reddish patches)
• Yersinia Enterolitica: Erythemia Nodosum
• Manifest pseudoapendicullar syndrome*
• -Bacillus Anthracis: Bloody Diarrhea
• Giardia Lamblia: Bloody Diarrhea
• Vibrious parahaemolyticus*: Summer Diarrhea (Kanagawa)
• *Traveller's Diarrhea( ETEC): Montezuma's Revenge/Turista
• Dysentery-like Shingella Infections**(EIEC): Intestinal Epithelium
• Enteropathic Escherichia coli: Infantile Diarrhea with large amount of mucus but without blood
• Enteroaggregative Escherichia coli: Acute and/or Chronic Diarrhea that adheres HEP2 cells packed in "Stacked Brick Pattern"
• Diffusely adhering Escherichia coli: Double Trouble of both Urinary Tract Infections and Gastrointestinal infections, or Acute pattern Escherichia coli *pattern:Pregnant women
• *Verotoxin 1: ingestion of poorly cooked meat may caused by bloody diarrhea to Verotoxin 1(Enterohemorrhagic Escherichia coli and Verotoxin 1)
• **E. coli 0157:H7 : Cause of *Enteric Disease Hemorrhagic Colitis that test negative"

Bacteria and Contamination

• In Blood Blank : Staphylococcus Epidermis/Yersinia Enterolitica(43)
• Acnes: Propianio Bacterium

Diseases

• Testanus(Tritanus Neratorum is a contaminated intrument by Newborns

• Lumpy Jaw -Acnes, bovis

• Food Botulism* - Clostridium Bartulinum (Home canned goods)

• Infant Bolutism* - VIA breast feeding

Lumpy Jaw

• Actinomyces bovis

Botulism

• Clostridium botulinum -Food Botulism-Spore ingestion

Cause of:

• Stillbirth:Listoria Monocytics

Ingestion of contaminated food can cause:

• (Coleslaw Of Softsheeese) ###Lysteria monocytogenes can cause : Conjuctivites-Cheriosis

Diphtheria -

• .Corynebacterium A droplet of infection characterized by mild shore throat and Exotoxin, can cause respiratory Toxins and Diptheria:
• Ulcerans and Marsits

Infections that are the rare cause of GRANULOMATOUS

• *Corynebacterium

Cauliflower-Like growth (35-37 C)

• mycobacterium tuberculosis -cause of TB
• Nosocomial infections that are pseudomonas* Diarrhea Hospital

Glanders Disease

• Burkholderia

CURRANT JELLY LIKE SPUTUM (Community Acquired Pneumonia)

• Klebsiella Pneumonia *** Lies in Summer Japanese and Gastroenteritis which is *Vparaly

• **Meliodosis or Glander's Like pneumonia- pseudo

• *Commonly know Oral Plaque- Aphrolis/Parphrolis

• Hansen caneti*

String test

• V. cholerae (+)
• K. pneumonia (-)
• Gram stain*- Red Porphin

Test

Organism

• Mycolibarian tuber*-

Grams staining

Black Car appearance

Types of Bacillus:

• *(C.WELHCHII)---- Box-CAR share
• *Ermengeis-Homemade

• ***Haffers"" bacteria""

Types of Pneumonia

• --Walking pneumonia-Ancho sauce

*Types of Paralysis

• Bacillus Tetanus* Spastic Paralysis
• clostridium Botulinum* Flacid Paralysis

Microsporide

• *"SATELLITISM"""

Test String for Test

• (k" pneumoniae)*
• Negative
• positive =cholerla

Gram-Positive Cocci*****

• Negative

*Markes *

• -Seplicurm

*Markes ***

" -Spirtiates.

• Twitching
• M.tuberculosis long

O2 Carbon

• --21%
• Aeronbes:
• Anaroberts: 0%

Temperature

• (30- 2)"
• 1-4
• Solv-

LIQUID

0 and

• Solitude: none

*Liquid *

• Semisolves-