Microbio lab part 2

Bacillus anthracis

Normal body site:

None

Clinical implication:

Anthrax

-Cutaneous: Wound

-Respiratory: Sputum, bronchial lavage

-Intestinal: Stool specimen

Bacillus anthracis morphology

G/S: Large, square ended GPR (sometime encapsulated)

^ look like bamboo rods from rods w/ spore

Morphology: large, gray, non hemolytic, medusa head

NON MOTILE

Bacillus sp

(B. subtilis)

Normal body site:

None

Clinical implication:

Food poisoning

Bacillus sp

(B. subtilis) Morphology

G/S: Large, spore forming GPR (spore looks like empty boxes)

Morphology: Large, yellow-gray, opaque, beta hemolytic

MOTILE

Corynebacterium sp.

Normal body site:

Skin

Upper resp tract: Nasopharynx & Oropharynx

Genitourinary tract

Clinical implication:

Occasionally infection in immunocompromised patients esp with catheters or prosthetic devices C. jeikeium

Occasionally causes UTI C.urealyticum

Corynebacterium sp. Morphology

G/S: Small GP palisading rods - uneven

Morphology: Pinpoint - small, (white, tan, gray, yellow, rarely black), opaque, non hemolytic

Listeria monocytogenes

Normal body site:

None (but sometimes colonizes ♀ genital tract

Clinical implication:

Sepsis (blood culture)

Neonatal meningitis (CSF)

Still birth or septic abortion (placenta or products of conception)

HINT: PLACENTA → INFECTION

Listeria monocytes morphology

G/S: Small GPR (close to one another: parrell sides)

Morphology: Small - medium, gray (translucent), narrow zone of beta hemolysis

Erysipelothrix sp

Normal body site:

None

Clinical implication:

Cutaneous infection - usually on hands w/ people who handle animal products (esp swine)

Erysipelothrix sp Morphology

G/S: Long slender GPR, that may form long filaments

Morphology: Pinpoint - small, gray (translucent), slightly non hemolytic or alpha hemolytic

Lactobacillus

Normal body site:

♀ genital tract

Mouth

Gastrointestinal tract

Clinical implication:

Sepsis (RARE)

Lactobacillus morphology

G/S: Long, slender GPR but may be pleomorphic

Morphology: Pinpoint - small, gray (transparent), alpha hemolytic

small GPR testing

Vietek or MALDI TOF methods

CATALASE +

Large gram postive spore forming rods

Anthracis: refrence lab for further testing

Bacillus: motile tube & M35-A2

CATALASE +

Lactose fermenters

Escherichia coli

Serratia marcescens (slow)

Enetrobacter aerogenes (slow)

Citrobacter freundii

Klebsiella pneumoniae

S.E.E.C.K (LF)

Non lactose fermenters

Proteus vulgaris

Proteus mirabilis

Providencia sp

Morganella morganii

Edwardsiella tarda

Shigella sp

Salmonella sp

CLSI Guide lines: M35-A2

Escherichia coli: LF, beta / non hemolytic, distinct (indole) odor, indole positive

Proteus mirabili: NLF, Swarming, oxidase and indole negative

Pseudomonas aeruginosa: NLF, oxidase positive, beta / non hemolytic, metallic sheen, odor

Candida albicans: Grams stain (GP reaction), “feet” on BA or CHOCO agar

Bacillus sp.: Gram stain (GPR spore forming), beta hemolytic, grainy colonies, catalase positive

Why we don’t gram stain enterics

MAC plates show lactose fermenters and non-fermenters which give us a clue what it might be

non fermenters need to be oxidase tested:

Oxidase test → no color → oxidase negative → NLF enteric

Escherichia coli

Normal body site:

GI tract

Clinical implication:

Most common cause of out patient UTI

Escherichia coli morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, beta hemolytic, indole odor

(MAC) LF

INDOLE +

Proteus vulgaris

Normal body site:

GI tract

Clinical implication:

UTI

Proteus vulgaris morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, beta hemolytic

(MAC) NF

Proteus mirabilis

Normal body site:

GI tract

Clinical implication:

UTI; less common wounds

Proteus mirabilis morphology

G/S: GNR

Morphology:

(BA) Gray, swarming

(MAC) NF

INDOLE +

Serratia marcescens

Normal body site:

GI tract

Clinical implication:

wound infection from burns

Serratia marcescens Morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, non hemolytic, red pigmented

(MAC) slow LF

Enterobacter aerogenes

Normal body site:

GI tract

Clinical implication:

most often cause nosocomial infections

Enterobacter aerogenes Morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, non hemolytic

(MAC) slow LF

Citrobacter freundii

Normal body site:

GI tract

Clinical implication:

most often cause nosocomial infections

Citrobacter freundii Morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, non hemolytic

(MAC) LF

Klebsiella pneumoniae

Normal body site:

GI tract

Clinical implication:

pneumonia - hospitalized patients

Klebsiella pneumoniae Morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, VERY mucoid, non hemolytic

(MAC) LF

Shigella sp

Normal body site:

None

Clinical implication:

Bacillary Dysentery

Shigella sp morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, non hemolytic

(MAC) NLF

Salmonella sp

Normal body site:

None

Clinical implication:

Enterocolitis, Bacteremia, Typhoid fever (rare in us)

Salmonella sp Morphology

G/S: GNR

Morphology:

(BA) medium - large, gray, mucoid, non hemolytic

(MAC) NLF

Enteric testing

MALDI - TOF & Vitek

OXIDASE -