The abc s of infections
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The ABC’s of Infections. Eleana M. Zamora, MD Department of Internal Medicine Division of Pulmonary/Critical Care/Sleep. Objectives. Understand the difference between nosocomial and community-acquired Know where to find antibiogram data

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The abc s of infections

The ABC’s of Infections

Eleana M. Zamora, MD

Department of Internal Medicine

Division of Pulmonary/Critical Care/Sleep


  • Understand the difference between nosocomial and community-acquired

  • Know where to find antibiogram data

  • Have a basic understanding of how to approach common infections in the inpatient and outpatient setting


  • Community vs. nosocomial

  • Upper/Lower respiratory infections

  • C.difficile-associated diarrhea

  • Intra-abdominal infections

  • Skin-soft tissue infections

  • Bacteremia

  • Osteomyelitis, septic joints

Urine antibiogram
Urine Antibiogram

Objectives crash course
Objectives: Crash Course

  • Commonly encountered infections in inpatient and outpatient settings

    • What bugs?

    • What drugs?

  • Common clinical syndromes

Community vs nosocomial
Community vs. Nosocomial

  • Why important?

    • Atypicals

    • MDRO

    • MRSA

    • Pseudomonas

  • Broadened definition of “nosocomial”

    • SNF, OPAT, jail, community-living, homeless, etc.

Common outpatient infections
Common Outpatient Infections

  • Upper respiratory

  • Lower respiratory

  • Sinusitis

  • Pharyngitis

  • UTI

  • SST

Upper respiratory infection
Upper Respiratory Infection

  • Def’n:

    • Acute infxn which is typically viral

    • Sinus, pharngeal, or lower airway symptoms may be present, but are not prominent

  • Abx are rarely indicated

    • Although most “colds” have sinus symptoms, less than 2% have complication of acute bacterial sinusitis

    • Presence of green mucus does not necessarily indicate bacterial infection

Acute pharyngitis
Acute Pharyngitis

  • GAS causes 10% of adult pharyngitis

    • 90% are NOT GAS!

    • DDx: EBV, CMV (less likely), gonococcus, HSV, HIV, Syphilis

  • ABX are rarely indicated for routine pharyngitis

    • Use the Centor diagnostic criteria to decide who to test

    • Treat only positive GAS rapid screens or patients who have all 4 criteria

Centor criteria
Centor Criteria

  • History of fever

  • Tonsillar exudates

  • No cough

  • Tender anterior cervical LAD

    ≥2 of the above = treat

Treatment of gas pharyngitis
Treatment of GAS Pharyngitis

  • Treatment of choice: Penicillin V 500mg BID or 250mg QID x 10 days

  • Alternatives

    • Benzathine PCN 1.2 MU IM x 1 dose (for noncompliant patients)

    • 2nd gen cephalosporin: cefuroxime or cefprozil 500 mg qday, etc. etc

    • Azithro 500mg x1, then 250mg po day x 4d

    • If macrolide failure or pcn-allergy: FQ

    • Bactrim does not cover GAS

Acute sinusitis
Acute Sinusitis

  • Most cases of sinusitis are viral

  • Bacterial rhinosinusitis

    • Sxlasting ≥7 d who have maxillary pain or tenderness in the face or teeth (esp. unilateral) and purulent nasal secretions

  • Severe dz: dramatic symptoms of severe unilateral maxillary pain, swelling, and fever.

Idsa treatment
IDSA: Treatment

  • First line = B-lactam (amox/clav)

    • Preferred over respiratory FQ

    • Doxycycline is equivalent to amox/clav

    • Not recommended to cover for MRSA

  • Not recommended for use:

    • Macrolides, Bactrim

  • Duration of tx: 5-7 days

    • Recommended over 10-14 days

Acute sinusitis1
Acute Sinusitis

  • Etiology

    • Community-acquired from obstruction of ostia, allergens, post-viral infxn:

      • S.pneumo 31%

      • H.influenzae 21%

      • M.catarrhalis 10%

      • S.aureus 4%

    • Diabetic, neutropenic, IV iron therapy:

      • mucor/rhizopus, aspergillus

Etiology of acute sinusitis
Etiology of Acute Sinusitis

  • Nosocomial , NGT, or nasal intubation:

    • Gram neg (pseudomonas, acinetobacter) 47%

    • Staph aureus/gram pos 35%

    • Yeast 18%

    • Polymicrobial 80%

Chronic sinusitis
Chronic Sinusitis

  • Pathogenesis is multifactorial

    • Smoking

    • Nasal polyps

    • Periodontitis

  • Antibiotics are rarely effective

    • Refer to ENT


  • Atypical pathogens

    • Prevotella, anaerobes, fusobacterium, Pseudomonas, fungi/molds

Non specific uri
Non-Specific URI

  • Resistant Strep pneumoniae

    • outpatient abx

    • Treating a viral URI with abx directly increases the risk of resistant bug transmission

  • Upper URI account for over 75% of outpatient RX each year

For uri syndromes
For URI Syndromes:

Very strongly consider NOabx:

ABX should be used for:

Documented GAS pharyngitis

Severe sinusitis with fever, ptosis, etc.

Pneumonia (LRI)

  • Adult uncomplicated acute bronchitis

    • Not acute exacerbations of chronic bronchitis)

  • Acute sinusitis

  • Pharyngitis

  • Nonspecific URI

Lower respiratory


Lower Respiratory

Lower respiratory infections
Lower Respiratory Infections

  • Tracheitis – biggest airways

  • Bronchitis –large airways

  • Bronchiolitis – smallest airways, wheezing

  • Pneumonia – air space infection

    • Basic concepts are the same for all

Stepwise approach
Stepwise Approach

  • Decide viral, bacterial, atypical, other?

    • Not always so easy…sometimes more than one

    • Rule of thumb: cover the top 3

    • Risk factors

      • Smoking, travel, immunosuppression, diabetes


  • Community-acquired vs. nosocomial +/- aspiration

    • Hospitalized vs. non-hospitalized

    • Remember new broader risk categories for MDRO

    • Pseudomonas and Acinetobacter longer duration of tx

Powers of pseudomonas prediction
Powers of Pseudomonas Prediction

Common cap etiologies
Common CAP Etiologies

IDSA CAP Guidelines 2007

To hospitalize or not
To Hospitalize or not?

  • Pneumonia severity index (PSI)

  • CURB-65

  • Your gut feeling counts

  • CURB-65

    • Confusion, Uremia, RR, low BP, age>65

    • Score > 2admit

Severe cap
Severe CAP

  • IDSA Guidelines 2007

Inpatient non icu cap tx
Inpatient, non-ICU CAP Tx

  • UNMH Formulary

    • Ceftriaxone + azithromycin/doxy

    • If β-lactam allergy: moxifloxacin

      • Moxi not for UTI or Pseudomonas

Inpatient cap icu
Inpatient CAP, ICU

  • UNMH Formulary

    • Ceftriaxone + azithromycin

      • Not doxy

    • If β-lactam allergy: moxifloxacin

Pseudomonal risk factors
Pseudomonal Risk Factors

  • UNM: Know the antibiogram!

    • Available to you without ID consult: Zosyn (87%S), Cefepime (82%), Cipro (72%), Gent/Tobra (85%)

    • ID Consult only: Meropenem (95%), amikacin (89%), doripenem, colistin

Clostridium difficile
Clostridium difficile

  • SHEA/IDSA Guidelines 2010

  • Who to test?

  • What to do?

  • How to treat?

  • When to take out of isolation?

The new cdad
The New CDAD

  • 4 x’s increase in cases over 13 year period

  • Increase in disease severity

  • Major risk factors for NAP1 strain

    • Age > 65

    • Recent use of FQs

Severity assessment score

≥2 points classified as severe

1 point given for each of the following:

Age > 60

Temp >38.3

WBC > 15K

Albumin < 2.5mg/dL

2 points for endoscopic evidence of CDAD

(Alternate: AKI)

(Alternate: sepsis, ICU)

Severity assessment score

Case definition
Case Definition

  • Presence of diarrhea (>3 unformed stools in 24 hours)

  • Stool test positive for Cdiff or its toxins

  • Colonoscopic evidence of Cdifficile

Who to test
Who to test?

  • Anyone with diarrhea?

    • Do not test asymptomatic patients

    • Only patients with diarrhea, not formed

      • Unless toxic megacolon/ileus

  • High risk:

    • SNF, jail, group home

    • Recent (<90d) abx

    • Recent (<30d) hospitalization

    • Known contact (2-3 days avg)

    • Severe, ICU intraabdominal source suspected

What test
What test?

  • Previously used test for toxin

  • UNMH uses PCR confirmation

    • A single test per episode of diarrheal illness is recommended

    • No more than one test every 7 days

    • Do not need multiple tests to “rule-out”

    • Do not need test of cure

Understanding the test
Understanding the test

  • Stool tested for Antigen (Ag) and toxin (T)

    • Ag (+) T (+)  positive C.diff (red)

    • Ag (+) T (-)  reflex to PCR (red)

    • Ag (-) T (+)  reflex to PCR (red)

    • Ag (-) T (-) negative C.diff

What to do
What to do?

  • If you think it, patient must be in isolation

    • NEVER EVER order the test without putting patient in isolation at same time

    • Never treat empirically without putting in isolation at same time

  • If patient is ill, empiric tx is ok

Complicated intra abdominal infections
Complicated Intra-abdominal Infections

  • Examples:

    • Perfdiverticulum

    • Complicated GB infection

    • Abscess

    • Peritonitis

  • Location matters

    • Flora of upper small bowel vs. from beyond small bowel vs. from beyond ileum vs. rectum

It s all about location
It’s All About Location!

  • Upper GI, duodenum, biliary system, proximal small bowel

    • Peritonitis common

    • Gram pos, gram neg aerobic and facultative organisms

    • Enterococcus is not a real concern

  • Distal small bowel

    • Less GPC, more GNR (aerobes, facultative)

    • Often evolve into abscesses (not peritonitis)

Location location location
Location, location, location

  • Colon

    • Facultative (E.coli) and obligate anaerobes (B.frag), Streptococci (S.bovis)

  • Abscesses

    • Abscesses, in general, should be drained

    • ABX have hard time getting into abscess

      • Exception?

    • ALWAYS send aspirate for anaerobic/aerobic culture

So why so complicated
So, Why So Complicated?

  • Location

    • Some drugs are inactive in abscesses

    • Some drugs are pH dependent

  • Bugs

    • Some bugs are resistant

      • B.frag vs. clinda/fq/cefotetan/cefoxitin

  • Community-Acquired vs. Nosocomial?

    • Pseudomonas is less common in abscesses

Who to treat
Who to Treat?

  • Bowel trauma that get surgically repaired within 12 hours, upper GI perf in the absence of antacids, or acute appendicitis

    • Abx used for <24h

  • Acute uncomplicated cholecystitis = NO

  • Ascending cholangitis = YES

  • Acute pancreatitis = NO

  • Necrotizing pancreatitis = YES

What to give
What to give?

Note: Empiric coverage of Candida is NOT recommended.

If candida is found, strongly consider if it needs therapy


  • Gonzales “Principles of Appropriate Antibiotic Use for Treatment of Nonspecific Upper Respiratory Tract Infections in Adults: Background” Ann Intern Med. 2001;134:490-494.

  • Cooper “Principles of Appropriate Antibiotic Use for Acute Pharyngitis in Adults: Background” Ann Intern Med. 2001;134:509-517.

  • Hickner “Principles of Appropriate Antibiotic Use for Acute Rhinosinusitis in Adults: Background” Ann Intern Med. 2001;134:498-505.

  • IDSA Guidelines or Acute BacerialRhinosinusitis in Children and Adults 2012

  • Gonzales R,“Principles of Appropriate Antibiotic Use for Treatment of Acute Respiratory Tract Infections in Adults: Background, Specific Aims, and Methods” Ann Int Med 2001; 134:479-486

  • Mandell, LA,“Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia in Adults” CID 2007;44:S27-72

  • Joint statement of ATS/IDSA 2004 “Guidelines for the Management of Adults with Hospital-acquired, Ventilator-associated, and Healthcare-associated Pneumonia” Am J RespirCrit Care Med 171:388-416

The abc s of infections

  • Cohen SH,“Clinical Practice Guidelines for Clostridium difficile Infection in Adults: 2010 Update by the Society for Heathcare Epidemiology of America (SHEA) and the Infectious Diseases Society of America (IDSA)” ICHE 2010;31(5): 000-000

  • Solomkin JS,“Diagnosis and Management of Complicated Intra-abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America.” CID 2010;50:133-64

  • Stevens DL,“Practice Guidelines for the Diagnosis and Management of Skin and Soft-Tissue Infections” CID 2005;41:1373-1406

  • Lipsky, BA,“Diagnosis and Treatment of Diabetic Foot Infections” CID 2004;39:885-910

  • Nicolle, LE,“Infectious Disease Society of America Guidelines for the Diagnosis and Treatment of Asymptomatic Bacteriuria in Adults” CID 2005;40-643-54

  • Hooton TM, “Diagnosis, prevention, and Treatment of Catheter-Associated Urinary Tract Infection in Adults: 2009 International Clinical Practice Guidelines from the Infectious Disease Society of America.” CID 2010;50:625-663.