Gram Positive Bacterianew

7/27/2019 Gram Positive Bacterianew

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GRAM POSITIVE

BACTERIAJoy N Bautista, RN, MPH, DRDM, MAN


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General Characteristics

Stains blue or violet on Gram stain

Peptidoglycan cell wall contains teichoic

acid and lipoids for chelation and

adherence

Contains cytoplasmic lipid membrane

Some contain capsular polysaccharides

Some have flagellum that contains 2 rings

for support


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Actinomyces

Species - A. israelli, A. gerencseriae, A.

georgiae, A. naeslundii, A. odolynticus, A.

Meyeri, A. pyogenes, Propionibacterium

propionicus

Infections:

Cervico-facial-face, neck, jaw, tongue

Thoracic via aspiration

Abdominal thru abdominal surgery,trauma, perforative diseases


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Bacillus

B. anthracis cutaneous, pulmonary, or

intestinal anthrax

B. cereus, B lichenformis, B subtilis food

poisoning , abscess, bacteremia,

septicemia, wound and burn infections, ear

infections, endocarditis, meningitis,

ophthalmitis, osteomyelitis, peritonitis, RTI,

UTI

B alvei, B brevis, B circulans, B coagulans,B macerans, B pumilus, B sphaericus, B

thuringiensis occasional infections


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Bacillus

Cutaneous anthrax 2-3 days incubation

Vesicles develop, central papule

ulcerates and dries then forms eschar

Painless lesion with edema Pus and pain appear only if

superinfected

Intestinal anthrax similar to cutaneous

Pulmonary anthrax alveolarmacrophages transport the spores to

lymph nodes


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Bacillus

B cereus food poisoning

Due to cereolysin necrotic and lethal toxin

Also due to phospholipases which degrades

host cell membranes Diarrheal diarrhea and abdominal pain 8-16

hours after eating contaminated food

Emetic nausea and vomiting 1-5 hours

after eating contaminated food (rice held forextended periods in ambient temperature

then quick-fried before serving)


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Clostridium

C perfringes, C noyvi, C septicum gas gangrene,wound infections, cellulitis, superficial contamination

of necrotic tissues

C tetani tetanus

C botulinumbotulism , food poisoning C difficile pseudomembranous colitis, antibiotic-

associated diarrhea

C perfringes food poisoning, necrotizing enteritis

C sordelli bacteremia, endometritis

C septicum colorectal cancer, leukemia,

lymphoma, sarcoma

C tertium bacteremia in neutropenic patients


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Clostridium: Gas Gangrene

C perfringes (10-48h IP); C septicum (2-3d

IP); C noyvi (5-6d IP)

Tissue trauma impaired blood supply

tissue hypoxia anaerobic growth

Release of exotoxins hemolysins,

collagenases, proteases, lipases tissue

necrosis and systemic toxemia

As more tissue dies, more clostridia grow and

multiply

Complications severe shock with massive

hemolysis and renal failure


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Clostridium: Tetanus

Bacterial growth in wound toxin secretion

Tetanospasmin blocks action of inhibitory

neurons blocks release of glycine and GABA

muscle rigidity and convulsions

Cramping and twitching of muscles around a

wound

Trismus pain in neck and jaw muscles (lock jaw)

Opisthotonus head and heels bent backward withbody bowed forward

Types generalized, localized, cephalic, neonatal


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Clostridium: Botulism

Food poisoning Due to toxins in improperly preserved food

S/Sx NV, abdominal pain, diarrhea, toxemia

Wound botulism -confined to necrotic tissues

Infant botulism

Due to germination of spores in the GIT

Usually between 2 weeks and 6 months of age

First sign constipation; then diminished suckingand gag reflexes, dysphagia, loss of head

control, flaccidity, respiratory arrest , death


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Clostridium: Colitis and Diarrhea

Mild diarrhea , severe abdominal pain with

fever

Watery diarrhea which may contain blood,

pus, or mucus C difficile is a normal flora of the GI

If with antibiotics, it competes with other

bacteria leading to overgrowth of C difficile

Release toxins enterotoxins and cytotoxins


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Clostridium: Other Infections

C perfringes food poisoning and

necrotizing enteritis

C sordellii bacteremia, endometritis, non-

bacteremic infections C septicum colorectal cancer, leukemia,

lymphoma, sarcoma

C tertium bacteremia in neutropenic

patients


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Corynebacterium

Rod-shaped, aerobic or facultative anaerobic

C diphtheriae causes diphtheria

Diphtheria URTI: fever, sore throat,

malaise with formation of gray-green fibrinpseudomembrane (dead epithelium, WBC,

RBC, fibrin)

Other species C tenuis, C striatum, C

minutissimum; pahogenic amongimmunocompromised individuals and those

with intravascular devices


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Corynebacterium

Diphtheria

Nasopharyngeal mild pharyngitis,

hypoxia, bull neck diphtheria, fever

Cutaneous gray-brownpseudomembranous skin lesions

Complications loss of motor function,

dysphagia, congestive heart failure (action

on peripheral motor neurons)


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Enterococcus

Common in intestines;

similar in morphology to

Stretococci

Often causes UTI,bacteremia, bacterial

endocarditis, diverticulitis,

meningitis

Resistant vs -lactams and

aminoglycosides

Species E faecalis, E

faecium


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Erysipelothrix Rhusiopthiae

Causes erysipeloid violet or

wine-colored inflammatory

lesion of the skin of the

fingers or hand characterized

by itching Complications septicemia,

endocarditis, arthritis without

fever

Pathogenesis bacteria

gains entry via skin injuryincubation period leads to

lesions recover in 2-3

weeks


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Listeria

Listeria monocytogenes causes listeriosis

Listeriosis food-borne meningitis and

sepsis in newborns

Pathogenesis Release of hemolysin to fight

phagocytosis production of listeriolysin

Actin polymerization to form filopods

Filopods contract cells leading edge tocontact adjacent cells which subsequently

ingests filopods


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Peptostreptococcus

Causes the following infections

Abscess of the brain, liver, abdomino-pelvic,

dental, tubo-ovarian

Intraabdominal sepsis

Aspiration pneumonia

Empyema

PID, ulcers, cellulitis

Fasciitis, osteomyelitis

Rarely, endocarditis, bacteremia Agents P anaerobius, P asaccharolyticus, P

hydrogenalis, P tetradius, P prevotii, P magnus, P

micros, S intermedius, S constellatus, G morbillorum


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Staphylococcus

S aureus

Causes superficial skin infections boils, furuncles,

styes, impetigo

Serious infections in immunocompromised patients

pneumonia, deep abscesses, osteomyelitis,

endocarditis, phlebitis, mastitis, meningitis

Toxins

Alpha inflammatory shock

Beta sphingomyelinase neuron membrane

damage Gamma- and leukocidins cell damage

Panton and Valentine leukocidin necrosis:

degranulation of neutrophils


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Staphylococcus

S epidermidis causes infections in patients with

indwelling devices: peritonitis, endocarditis

S. saprophyticus, S simulans, S cochnii, S warneri, S

lugdunensis cause endocarditis

Pathogenesis:

Fibronectin promote clot attachment to traumatized

tissues

Hemolysis by toxins

WBC membrane damage by leukocidins

Septic shock by alpha toxins Toxic shock by enterotoxins and toxic shock syndrome

toxin

Scalding skin syndromes in neonates by epidermolytic

or exfoliative toxins


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Streptococcus

Group A streptococcus

S pyogenes - beta-hemolytic streptococci

completely destroys blood cells.

Leading cause of streptococcal pharyngitis or strep

throat, acute rheumatic fever, scarlet fever, acute

glomerulonephritis, and necrotizing fasciitis.

May also produce sinusitis, otitis, mastoiditis,

pneumonia with empyema, joint or bone infections,

myositis, meningitis, endocarditis, impetigo, and/or

cellulitis.

Toxins streptolysin S and O (leukotoxic),hyaluronidase, streptokinase (fibrin lysis),

streptodornases A-D (disables DNA activity),

streptodornases B and D (disables RNA activity),

proteases (TSS and soft tissue necrosis)


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Streptococcus

Pneumococci

S pneumoniae - alpha-hemolytic streptococci

partially hemolyses blood cells.

Leading cause of bacterial pneumonia in infants and

occasional cause of acute bacterial otitis media,

sinusitis, meningitis, and peritonitis.

Dissemination from a respiratory focus results in

outpatient bacteremia in children, meningitis, acute

septic arthritis and bone infections in patients with

sickle cell disease, and peritonitis or endocarditis.

Pathology: resistant to phagocytosis d/t bacterialcapsule stimulation of PMNs, changes in

permeability and perfusion, cytokine release,

stimulation of platelet activating factor


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Streptococcus

Lancefield group streptococci - beta-hemolytic

streptococci

S agalactiae (Group B) causes some of neonatal

infections such as neonatal septicemia and

meningitis.

Mortality rates in full-term infants range from

2-8%; pre-term infants 30%.

Early-onset neonatal disease (associated

with sepsis, meningitis and pneumonia at 6

days of life) via vertical transmission.

Late-onset (from 7 days to 3 months age)meningitis via horizontal transmission, in

some instances as a nosocomial infection.

Pneumonia in elderly patients


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Streptococcus

Lancefield group streptococci

S agalactiae (Group B)

Adult urinary tract infection, chorioamnionitis and

endometritis, skin and soft tissue infection,

osteomyelitis, meningitis, bacteremia without

focus, and endocarditis.

Infection in patients with HIV

Group F streptococci produces abscess formation

and purulent diseases.

Anaerobic streptococci produces serious mixed

infections of the female genital tract as well as brain,pulmonary, and abdominal abscesses.


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Streptococcus

Viridans streptococci

Alpha-hemolytic streptococci that produce

exopolysaccharide associated with the ability to

adhere to cardiac valves.

S mutans and S sanguis produce dental caries.

S mitis produce bacteremia, meningitis, periodontaldisease, and pneumonia.

S milleri is associated with suppurative infections.


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Streptomyces

Rarely cause human diseases

More important in the production of antibiotics

S somaliensis causes actinomycotic mycetoma

localized swollen nodules in the feet that slowly enlarge

Pathology: soil organism enters via tissue trauma then

spreads to SQ tissue then the bone where it drains asgranulytic pus.

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Gram Positive Bacterianew

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