Osteomyelitis (organisms)

Hematogenous spread - thru blood stream

usually monomicrobial

< 16 -femur, tibia, humerus

Adult - vertebrae

1. < 16 y/o:

• S. aureus (60-90%)
• S epi
• S pyogenes
• S. pneumonia
• H. flu
• P. aeroginosa
• enterobacter
• E coli

2. Adult:

• S aureus 
• gram neg bacilli

3. Sickle cell anemia:

• Salmonella (67%)
• s. pneumoniae

4. IV drug users:

• p. aeruginosa

Osteomyelitis (organisms)

Contiguous spread

spread from adjacent tissue or direct inoculation

Adults 35-50 y/o

femur, tibis, skull

Usually mixed infections

• S. aureus (60%)
• S. epi
• Stretococcus
• gram neg bacilli - P. aeruginosa-foot punctures; Proteus, Klebsiella, E coli
• Anaerobic (human bites, decubitus ulcers)

Osteomyelitis (organisms)

Vascular insufficiency

Insufficient blood supply to fight bacteria- diabetes, PVD, Post Cabg (sternum) - - Adults > 50 y/o

Usually polymicrobial

• S aureus
• S. epidermidis
• Streptococcus
• gram neg bacilli
• anaerobic (bacteriodes fragilis group)

Infected prosthesia:

S. aureus

S. epidermidis

Osteomyelitis

Diagnostic criteria

Signs & symptoms

• fever
• chills
• localized pain, tenderness and swelling
• neurologic symptoms if spinal cord compression

Tests

elevated WBC, ESR, CRP

x-ray: lag behind infectious process

CT or MRI

radionuclide positive 24-28 hrs afte infection begins

Osteomyelitis

Treatment

(6 groups)

Length of therapy:

• Acute: 4 - 6 weeks
• Chronic: 6 - 8 weeks of IV & 3 - 12 months of oral

Neonates < 1 month

• nafcillin + cefotaxime
• nafcillin + aminoglycoside

Infants (1-36 months)

• Cefuroxime
• ceftriaxone
• nafcillin + cefotaxime

Pediatrics (> 3 years old)

• nafcillin
• cefazolin
• clindamycin

Adults

• nafcillin
• cefazolin
• vancomycin

Sickle cell anemia

• nafcillin + ampicillin

Prosthetic joint

• vancomycin + rifampin
• nafcillin + rifampin

Central Nervous System Infections

Septic Meningitis

Organisms ( 4 groups)

Newborns (< 1 month)

• S. agalactiae
• E. coli
• Klebsiella species
• Enterobacter species
• Less common: listeria monoctogenes & herpes simplex type 2)

1 month to 2 years

• S. pneumoniae
• N.meningitidis
• S. agalactiae
• H. flu
• Less common: viruses & E. coli

2 to 50 years old

• N. Meningitidis
• S. Pneumoniae
• less common: viruses

> 50 years old

• S. pneumoniae
• N. meningitidis
• Less common: L. monocytogenes, aerobic gm neg bacilli, viruses

Central Nervous System Infections

Aseptic Meningitis

• viral
• fungal
• parasitic
• tubercular
• syphilis
• Meds: (e.g.bactrim, ibuprofen)

Central Nervous System Infections

Septic Meningitis

Predisposing risk factors

• Head trauma
• immunosuppression
• CNS shunts
• cerebrospinal fluid fistula/leak
• neurosurgical patients
• alcoholism
• local infections (sinusitis, otitis media, pharyngitis, bacterial pneumonia)
• splenectomized pts
• sickle cell disease
• congenital defects

Central Nervous System Infections

Septic Meningitis

(Signs & symptoms)

• fever
• chills
• headache
• backache
• nuchal rigidity
• mental status changes
• photophobia
• nausea &/or vomiting
• anorexia
• poor feeding habits (infants)
• petechiae/purpura (N. meningitidis meningitis)
• brudzinski sign
• kernig sign
• bulging fontanel

Brudzinski's sign of meningitis

Bacterial Meningitis

lab results

• Increased WBC with left shift (an increase in immature leukocytes due to proliferation and release of granulocyte and monocyte precursors in the bone marrow which is stimulated by several products of inflammation including C3a and G-CSF)
• CSF culture (positive in 75-80%)
• CSF gram stain
• Blood cultures
• C-reactive protein - high negatvie predictive value

CNS infection (Meningitis)

Empiric therapy

Neonates < 1 month

• Ampicillin + aminoglycoside
• Ampicillin + cefotaxime

Infants: 1 to 23 months

• 3rd generation cephalosporin (cefotaxime or ceftriaxone) + vancomycin

Pediatrics & adults (2 to 50 y/o)

• 3rd generation cephalosporin (cefotaxime or ceftriaxone) + vancomycin

Elderly ( >/= 50 y/o)

• 3rd generation cephalosporin (cefotaxime or ceftriaxone) + ampicillin + vancomycin

Penetrating head trauma, post neurosurgery or CSF shunt

• Vancomycin + cefepime, ceftazidime or meropenem

CNS infections

Meningitis

Pathogen: S. pneumoniae

Length of therapy: 10 - 14 days

MIC ^_</= 0.1mcg/ml

• PCN G 4 million units IV q4h
• Ampicillin 2gm IV q4h
• Alternative: 3^rd gen cephalosporin or chloramphenicol

MIC 0.1 to 1 mcg/ml

• 3rd gen cephalosporin
• Alternative: cefepime or meropenem

MIC _^>/= 2

• Vancomycin + 3rd gen cephalosporin
• alternative: moxifloxacin

CNS infections

Meningitis

Pathogen: N. meningitidis

Length of therapy: 7 days

MIC < 0.1mcg/ml

• PCN G 4 million units IV q4h
• Ampicillin 2g IV q4h
• Alternative: 3rd gen cephalosporin or chloramphenicol

MIC 0.1 - 1 mcg/ml

• 3rd gen cephalosporin
• alternatives: chloramphenicol, fluoroquinolone or meropenem

CNS infections

Meningitis

Pathogen: H. Influenzae

Length of therapy: 7 days

B lactamase negative

• Ampicillin 2g IV q4h
• Alternative: 3rd gen cephalosporin, cefepime, chloramphenicol, fluoroquinolone

B lactamase positive

• 3rd gen cephalosporin
• Alternative: cefepime, chloramphenicol, fluoroquinolone

CNS infection

Treatment

Pathogen: S. agalactiae & Listeria moncyogenes

S. agalactiae

• Pen G 4 million units IV q4h
• Ampicillin 2 g IV q4h
• Alternative: 3rd generation cephalosporin

Listeria monocytogenes

• Pen G 4 million units IV q4h
• Ampicillin 2 g IV q4h
• Alternative: Bactrim or meropenem

CNS infection

Meningitis

Adjunctive corticosteroid therapy

Use in children with H. flu meningitis or in adults with pneumococcal meningitis, may need to initiate before causative bacteria known

administer 10 to 20 min before or at same time as ABX's

Dexmethasone 0.15mg/kg q6h for 2 to 4 days

Risks/benefits:

• reduces hearing loss & other neuro sequelae in children being treated for H. flu
• decreases mortality, improved outcomes in adults being treated for S. pneumoniae
• May decrease ABX penetration (vanco penetration decreased in animals after dexamethasone)

CNS infection

Meningitis

Prophylaxis for S. pneumoniae

Pneumococcal conjugate vaccine (13 valent)

• < 23 months
• 24 months to 59 months with high risk status (day care, certain chronic diseases, alaskan, american indian, african american)

Pnemococcal polysaccharide vaccine (23 valent)

• high risk status (day care, certain chronic diseases, alaskan, american indian, african american)

CNS Infections

Meningitis

Prophylaxis N meningitidis

Chemoprophylaxis: close contacts (household or daycare) and exposure to oral secretions or index case

Rifampin

• adults: 600mg q12h x 4 doses
• Children: 10mg/kg q12h x 4 doses
• Infants (< 1 month) 5mg/kg q12h x 4 doses

Ciprofloxacin

• 500mg orally x 1 (adults only)

Ceftriaxone

• 125-250mg IM x 1

VACCINES

Meningococcal polysaccharide vaccine (menomune) 

 > 55 y/o

Meningococcal conjugate vaccine (menactra)

• young adolescents (11-12 y/o)
• college freshman living in dorms
• military recruits
• travel to menigitis belt of Africa and Asia, Saudi Arabia for Islamic Hajj pilgramige
• asplenia
• terminal complement component deficiencies
• outbreaks of meningococcal disease

Booster

• adolescents 16y/o if inital dose received at 11-12 y/o or 5 years after 1st dose up to 21 y/o

CNS Infections

Meningitis

Prophylaxis  H. Flu

Everyone in the household with unvaccinated children

Rifampin

• Adults: Rifampin 600mg/day x 4 days
• Children (1 month to 12 years) 20mg/kg/day x 4 days
• Infants (< 1 month) 10mg/kg/day x 4 days

VACCINE type B polysaccharide

• All children
• Indications regardless of age:

aplenia

sickle cell disease

Hodgkin disease

hematologic neoplasms

solid organ transplant

severely immunocompromised (non - HIV related)

consider patients with HIV infection

Pathophysiology:

-direct extension or retrograde septic phlebitis from otitis media, mastoiditis, sinusitis, facial cellulitis

-hematogenous, pariticularly lung abscess or infective endocarditis

Signs & symptoms:

• Expanding intracranial mass leion, focal neuologic deficits
• headache
• fever
• seizures
• mortality - 50%

Microbiology:

usually polymicrobial

• Streptococcus 50-60%
• anaerobes 40%

Treatment:

I&D by craniotomy of needle aspiration

Empiric regimens based on source of infections:

• otitis media or mastoiditis: flagyl + 3rd gen cephalosporin
• Sinusitis: flagyl + 3rd gen cephalosporin
• dental sepsis: PCN + flagyl
• Trauma or post neurosurgery: Vanco + 3rd gen cephalosporin
• Lung abscess, empyema: PCN + falgyl + sulfonamide
• Unknown: Vanco + flagyl + 3rd gen cephalosporin
• Corticosteroids: if increased intracranial pressure

Endocarditis

Signs & symptoms

Lab results

Complications

Signs & symptoms:

• fever - low grade and remittent
• cutaneous manisfestations 50% of pts: petechiae (including conjunctival), Janeway lesions, splinter hemorrhage
• Cardiac murmur (90% of pts)
• arthralgias, myalgias, low back pain, arthritis
• fatigue, anorexia, weight loss, nights sweats

Labs:

• anemia, normochromic, normocytic
• leukocytosis
• elevated ESR (erythrocyter sedimentation rate) and CRP (C-reactive protein)
• Positive blood culture (78-95% of pts)

Complications:

• CHF (38-60%)
• Emboli (22-43%)
• Mycotic aneurysm (5-10%)

Endocarditis

organisms

3 to 5 blood cultures should be drawn during 1st 24 to 48 hours

Empiric therpy to be started in acutely ill pts only (draw 3 blood samples during 15-20 min before initiating antibiotics

Incidences:

Streptococcus   50%

S. aureus         25%

Enterococcus      8%

Coag neg staph  7%

gram neg bacilli  6%

candida albicans  2%

Endocarditis

Treatment

Streptococcus viridans

PCN MIC </= 0.12mcg/ml

PCN MIC > 0.12mcg/ml

Endocarditis

Treatment

Staphylococcus

MSSA

MRSA

Endocarditis

Treatment

Enterococcus

PCN resistant

Unasyn or Vanco + Gentamicin  for 6 weeks in either type of valve     

Endocarditis

Treatment

E. faecium & E. faecalis

E. faecium

(PCN, aminoglycoside & vanco resistant)

E. faecalis

(PCN, aminoglycoside & vanco resistant)

Endocarditis

Treatment

HACEK group

(haemophilus, Actinobacillus, cardiobacterium, elkenella, kingella)

Endocarditis

Conditions/procedures that require prophylaxis

Conditions

• prosthetic cardiac valves
• previous bacterial endocarditis
• congenital heart disease
• unrepaired cyanotic congenital heart disease
• completely repaired congenital heart defect w/prosthetic material/device (6 months after procedure
• cardiac transplant recipients with cardiac valvulopathy

Procedures

1. Dental involving gingival tissues pr periapical region of tooth)
2. respiratory tract (tonsillectomy, adenoidectomy, surgical procedures involing incidion or biopsy of respiratory mucosa)

endocarditis

Prophylaxis

Antibiotic options

Standard general:

Amoxicillin 2gm (child 50mg/kg) 1 hour prior to procedure

Unable to take oral:

• Ampicillin 2gm (child 50mg/kg) IV/IM within 30 min before procedure
• Cefazolin or ceftriaxone 1gm IV/IM (child 50mg/kg) IM/IV within 30 min before procedure

 PCN allergy:

• Clindamycin 600mg (child 20mg/kg) 1 hour prior to procedure
• Cephalexin 2g (child 50mg/kg) 1 hour prior to procedure
• Azithromycin or clarithromycin 500mg (child 15mg/kg) 1 hour prior to procedure

PCN allergy & unable to receive oral meds:

• Clindamycin 600mg IV (child 20mg/kg) within 30 min before procedure
• Cefazolin or Ceftriaxone 1gm IV/IM (child 50mg/kg) within 30 min before procedure

Peritonitis/intra-abdominal infections

Etiology (14)

• alcoholis cirrhosis & ascites
• acute hepatitis
• CHF
• SLP (lupus)
• metastatic malignancy
• peptic ulcer perforation
• appendicitis
• perforation of GI organ
• endometritis secondary to intrauterine device
• bile peritonitis
• pancreatitis
• operative contamination
• diverticulitis
• intestinal neoplasms
• peritoneal dialysis

Peritonitis/intra-abdominal infections

microbiology

3 groups

1. Stomach/proximal small intestine
2. Ileum
3. Large intestine

Stomach/proximal small intestine

• aerobic & facultative gram positive and gram neg (E. coli, streptococcus, enterococcus, klebsiella, proteus, enterobacter)

Ileum

• E. coli
• enterococcus
• anaerobes

Large intestine

• obligate anaerobes (bacteroides, clostridium perfringens)
• aerobic & facultative gram positive & gram neg (E. coli, streptococcus, enterococcus, klebsiella, proteus, enterobacter)

Peritonitis/intra-abdominal infections

clinical manifestations  (signs/symptoms)

• fever
• tachycardia
• increased WBC
• Abd pain aggravated by motion
• rebound tenderness
• bowel paralysis
• pain with breathing
• decreased renal perfusion
• ascitic fluid (protein > 3gm/dl; exudate fluid; WBC-many, primarily granulocytes)

Peritonitis/intra-abdominal infections

Therapy/prophylaxis

indication/lenth of therapy

• bowel injuries caused by trauma that are repaired within 12 hrs -treat for < 24 hours
• intra-op contamination by enteric contents-treat for < 24 hrs
• perforations of the stomach, duodenum & proximal jejunum (unless on antacid therapy or malignancy)-prophylactic antibiotics for < 24 hrs
• acute appendicitis without evidence of perforation, abscess or peritonitis - treat for < 24 hrs

Peritonitis/intra-abdominal infections

Treatment

Mild to Moderate community acquired infection (7)

Duration 4 to 7 days (unless source control is difficult)

• cefoxitin
• cefazolin, cefuroxime, ceftriaxone or cefotaxime + metronidazole
• ticarcillin/clavulanate
• ertapenem
• moxifloxacin
• cipro or levaquin + metronidazole
• tigecycline

Peritonitis/intra-abdominal infections

Treatment

High-risk or severe community-acquired or health care acquired infection (4)

Duration 4 to 7 days (unless source control is difficult)

• Zosyn
• ceftazidime or cefepime + metronidazole
• imipenem/cilastatin or meropenem or doripenem
• cipro or levaquin + metronidazole (not for Healtcare acquired infections)

Clostridium Difficile

Risk factors

hospitalization

medical comorbidities

extremes of age

immunodeficiency states

use of broad spectrum antibiotics for extended periods

Clostridium Difficile

Symptoms

& new strain

Symptoms:

watery diarrhea

abdominal pain

leukocytosis

GI tract complications

New strain:

BI/NAP1

produces more enterotoxin & binary toxin

increased sporulation capacity

resistant to fluoroquinolones

increased risk of flagyl failure, morbidity & mortality

Clostridium Difficile

Treatment

Initial/1st occurence (2)

2nd & 3rd recurrence (5)

Initial & 1st recurrence:

Metronidazole 500mg po/IV 3x/day for 10-14 days

Vancomycin 125mg po 4x/day for 10-14 days

2nd & 3rd recurrence:

• consider higher doses of vancomycin 500mg po 4x/day
• taper: vancomycin 125mg po 4x/day for 14 days, 2times/day for 7 days and daily for 7 days
• pulse therapy: vancomycin course for initial 10-14 days followed by vancomycin every other day for 8 days, then every 3 days for 15 days
• Consider rifampin 400mg 2x/day for 14 days
• Consider nitazoxanide 500mg 2x/day for 10 days

Antibiotic Prophylaxis

Gastrointestinal Surgery

Gastric/duodenal

1. Acidic, relatively little normal flora
2. Intragastric organisms & post-op infections increases with increasing pH
3. Indicated for:

• morbid obesity
• esophageal obstruction
• decresed gastric acidity
• decreased GI motility

Cefazolin 1-2 gram preinduction

Antibiotic Prophylaxis

Gastrointestinal Surgery

indications & treatment

Biliary

1. biliary tract normally has no organisms
2. Indicated for high risk (often intra-op colangiography shows unexpected common dust stones, some studies recommend ABX's in all biliary surgery

• acute cholecystitis
• obstructive jaundice
• common duct stones
• age > 70 years old

Cefazolin (or cefoxitin 1-2 gram preinduction

Antibiotic Prophylaxis

Gastrointestinal Surgery

indications & treatment

Appendectomy

• Acutely inflamed or normal appendix: < 10% risk
• Evidence of perforation: > 50% risk (treatment required)
• If perforated: treat for 3 to 7 days

Cefoxitin 1-2 gram (or cefazolin + metronidazole or unasyn) preinduction

Antibiotic Prophylaxis

Gastrointestinal Surgery

indications & treatment

Colorectal

• 30-77% infection rate without ABX's
• 1 of the few surgical procedures iin which coverage for aerobes & anaerobes has proved most effective
• combined oral & parental regimens may be better than parenteral regimens alone

1. cefoxitin 1-2gram (or cefazolin + metroniazole or Unasyn or ertapenem) preinduction
2. Gent/Tobra 1.5mg/kg and Clindamycin-metronidazole 0.5-1gm preinduction

with or without neomycin 1gm and erythromycin 1gm at 19, 18, & 9 hours before surgery or neomycin 2gm & metronidazole 2gm at 13 & 9 hours before surgery

mechanical bowel prep is not recommended & may be harmful

Antibiotic Prophylaxis

Obstetrics/gynecology

Vaginal/abdominal hysterectomy

indications & treatment

most effective in vaginal hysterectomies but generally given for both procedures

Cefazolin or cefoxitin 1-2gm (or unasyn) preinduction

Antibiotic Prophylaxis

Obstetrics/gynecology

Cesarean section

treatment

Antibiotic Prophylaxis

Cardiothoracic Surgery

indications & treatment

reduce risk of mediastinitis

cefazolin or cefuroxime 1-2gm preinduction ( plus intra-op doses)

if MRSA is probable or pt has been hospitalized - vancomycin

Antibiotic Prophylaxis

Cardiothoracic

pulmonary resection

indications & treatment

lobectomy and pneumonectomy

cefazolin or cefuroxime 1-2gm preinduction (or vancomycin)

Antibiotic Prophylaxis

cardiothoracic

Vascular surgery

indications & treatment

high mortality with infected grafts

cefazolin 1gm preinduction & q8h x 3 doses

If MRSA is probable: use vancomycin

Antibiotic Prophylaxis

Orthopedic

indications & treatment

indicated when surgery involves prosthetic materials (total hip/knee, nail or plate)

cefazolin 1-2gm preinduction

(or cefuroxime or vancomycin)

Antibiotic Prophylaxis

Head & Neck Surgery

indications & treatment

indicated  for major surgical procedures when an incision is made the oral or pharyngeal mucosa

give preinduction:

1. cefazolin 1-2gm
2. Unasyn 1.5-3gm
3. gent 1.5mg/kg & clinda 600-900mg

Antibiotic Prophylaxis

Urologic Surgery

indications & treatment

In general: not recommended

Indicated: + urine culture before surgery (treat then operate)

If therapy unsuccessful, cover for infecting organism & operate