Resident Version
Prevention of Healthcare Associated Infections and
Antimicrobial Resistance Module
Created by Dr. Wendy Gerstein
Updated 5/09
Objectives:
1) Describe appropriate isolation precautions for three different infections.
2) List three risk factors associated with hospital acquired infections (including UTI,
HAP/VAP, bacteremia), and two ways to minimize risks.
3) Know appropriate antibiotic therapy for three hospital acquired infections.
References:
1) Kollef MH. The Role of Antibiotics in the Management of Serious HospitalAcquired Infections. www.medscape.com 5/30/06.
2) Ramphal R. and Ambrose PG. Extended-Spectrum B-lactamases and Clinical
Outcomes: Current Data. CID 2006:42 (Suppl 4). S164-S172.
3) Garnacho-Montero J, Garcia-Garmendia JL, Barrero-Almodovar, et al. Impact
of adequate empirical antibiotic therapy on the outcome of patients admitted to the
intensive care unit with sepsis. Crit Care Med 2003; 31:2742-2751.
4) Sefton AM. Mechanisms of Antimicrobial Resistance – Their Clinical Relevance in
the New Millennium. Drugs 2002; 62 (4):557-566.
Case:
HPI: 80 yo male with history of quadriplegia, suprapubic catheter, and multiple UTIs, is
admitted from the nursing home due to fevers/nausea, not feeling well, and suprapubic
tenderness. Patient had recently completed 2 week course of IV ceftazidime for an
Acinetobacter UTI, with picc line still in place at time of transfer to hospital.
Pmhx:
1) c5-c7 quadraplegia from accident
2) Chronic suprapubic catheter
3) Recurrent uti’s
4) Diabetes
5) Hepatitis C
6) OSA
Allergies: pcn, keflex – can’t remember reaction. Has tolerated cephalosporins in past.
Current medications:
Macrobid 100mg bid – recently started in nursing home when repeat UA was positive.
Pyridium
Baclofen
Tylenol
Metformin
bowel regimen
Shx: lives in nursing home for many years, no etoh/drug abuse. Family involved.
PE: T 97.4, P 72, BP 100/72, RR 18
Gen: alert, oriented, laying in bed, no distress noted
Heent: perrla, eomi, neck supple, mouth pink/moist without lesions/exudate, fair dentition
Lungs: ctab, no crackles/wheezes, fair air movement
CV: reg, s1s2, soft sem lusb, no radiation, no gallup/rub
Abd: +bs, soft, mildly tender in lower quadrants, no masses, suprapubic catheter with
mild erythema/irritation around site, no pus/discharge.
Ext: flaccid, no ulcers/rashes, no evidence for embolic phenomenon, picc site LUE –
clean/dry, no swelling/tenderness/erythema.
Labs: wbc 9.1, hct 33, platelets 219
Chem 7 wnl, creatinine .5
2/2 Blood cultures growing GPC in clusters and chains, final ID with VRE and MRSA
UA positive with LE, nitrites, many WBC and clumps, final culture with ESBL
producing Acinetobacter.
1. How would you manage this patient?
2. What is his number one problem?
3. What is the most likely source for the bloodstream infection?
4. Second problem?
5. What antibiotic coverage would you pick for both problems?
6. Duration of therapy?
Outline for discussion:
1) Review of isolation precautions:
A. Standard:
 Gloves with any body fluid, hand washing, mask/gown if splashing
possible.
B. Airborne: small droplet nuclei.
 This includes TB, measles, varicella, disseminated zoster (or localized
zoster in immunosuppressed). Patient needs a private room, negative air
pressure with exhaust to outside, N95 mask for contacts (standard surgical
mask for patient if leaving room).
C. Droplet: large particle aerosols.
 Meningococcal, plague, pertussis, influenza, parvo B19, rubella, mumps.
No special air handling needed; need standard surgical mask on contacts.
D. Contact: infection spread through direct contact.
 Includes VRE, MRSA, C. diff, fecal/oral infections, herpes simplex,
zoster, varicella, and scabies. Contacts wear gloves; use gowns if
substantial contact anticipated.
2) Common healthcare associated infections (HAI): Risk factors and prevention
(In American hospitals alone, healthcare-associated infections account for an estimated 1.7 million
infections and 99,000 associated deaths each year.)
A) UTI:
 Most common HAI, 7000 deaths/year in US.
 Risk factors include presence of indwelling catheter, diabetes, ureteral
stents, female.
 On average, 20% of hospitalized patients get catheter, left for 2-4 days.
 Prevention: no unnecessary catheters, remove ASAP, use condom
catheter, and use aseptic technique with placement.
B) Nosocomial pneumonia (HAP & VAP):
 Leading cause of death from HAI
 Mortality 20-50%.
 Risk factors: mechanical ventilation, age >70, chronic lung disease,
aspiration, h2 blockers, NGT, prior antibiotics.
 Prevention/? Protective: sucralfate, semi-recumbent position in bed,
special ETT tubes (silver coated ETT, ability to aspirate secretions from
subglottic space), oral hygiene in intubated patients with chlorhexidine.
D) CVC/blood stream infections:
 250,000 cases/year in US.
 Crude mortality approximately 27%.


Risk factors: CVC present, elderly, malnourished, skin breakdown/burns,
neutropenia, location of CVC (IJ>subclavian), duration (risk increases
after 6 days for CVC), type of catheter, and care of catheter.
Prevention: Aseptic technique with placement (full barrier), cutaneous
disinfection with chlorhexidine, subclavian site (decreased risk of
infection), and remove catheter as soon as not needed (do not leave for
convenience).
E) C. difficile colitis:
 3 million new cases/year, spores found widely in hospital environment;
fecal-oral route of infection.
 >20% of patients become new carriers during a hospitalization, 1% will
become symptomatic.
 Risk factors: antibiotics, GI surgery, infected roommate, proton pump
inhibitors (allows viable spore to pass thru stomach).
 Prevention: meticulous hand washing using soap and h20 (alcohol gels not
effective), gloves/gowns, stop all unnecessary antibiotics. Vaccine has
been developed – partially purified inactivated toxin A and B – used
successfully in 3 patients with recurrent C. difficile colitis, need RCT. No
role yet for decontamination of carriers – high recurrence rate.
3) Acquired antimicrobial resistance:
A) Specific organisms/mechanisms:
Methicillin resistant S. aureus (MRSA):
a. Have mech A gene which determines low affinity penicillin binding
proteins causing methicillin resistance.
Vancomycin intermediate/resistant S. aureus (VISA/VRSA):
b. 100 VISA isolates to date, 6 VRSA. In 4/6 of these VRSA, the vanA
gene complex (from a VRE) was acquired by a MRSA strain,
transforming the S. aureus to VRSA.
Vancomycin resistant enterococcus (VRE):
c. The transposable van gene complexes impart resistance to vancomycin
by forming an alternative pathway for bacterial cell wall synthesis,
which alters binding targets for vancomycin.
Extended spectrum beta lactmases (ESBLs) gram negative rods:
d. Have plasmid mediated bacterial enzymes that are able to hydrolyze a
wide variety of penicillins and cephalosporins. These plasmids and
transposons are able to transfer between different strains and species of
bacteria. ESBL producing bacteria are resistant to almost all beta
lactams, although most are still sensitive to carbapenems.
Quinolone resistant GNRs:
e. Chromosomal mutations cause over expression of endogenous efflux
pumps (pump drug out of bacteria), or decreased cell wall
permeability.
B) Clinical issues/relevance:
MRSA:
f. >60% of ICU S. aureus isolates are MRSA.
g. Increased mortality (OR 1.93), increased length of stay (2-5 days on
average), and increased costs (ranges from $7,000-39,000 more per
episode).
h. Risk factors: prior antibiotics, prolonged hospitalization, recent
surgery, ICU stay, immunosuppression.
i. Treatment based on sensitivities (HA-MRSA vs. CA-MRSA), type of
infection (bacteremia vs. soft tissue or UTI). Older drugs may be
useful (bactrim, doxycycline, clindamycin). New available drugs
include linezolid, daptomycin, tigecycline.
VRE :
 30% of enterococcus isolates in ICUs in US are VRE.
 Increased morbidity seen in liver transplant patients, and increased
mortality associated with VRE bacteremia in neutropenic patients.
No difference in cost or length of stay (between VRE and VSE) in
ICU patients.
 Risk factors: vancomycin treatment, abdominal surgery, prolonged
antibiotic therapy, immunosuppression.
 Treatment options for serious infections: linezolid, daptomycin,
tigecycline. Uncomplicated UTIs – nitrofurantoin, levofloxacin if
susceptible (improved susceptibility in vitro over ciprofloxacin).
ESBLs:
 14% of Klebsiella, 6.4% of E. coli in US.
 Data is conflicting regarding increased costs and length of stay.
 Inappropriate initial antimicrobial therapy in septic patients
significantly increases in-hospital mortality.
 Risk factors: delay in effective antibiotic coverage, invasive
medical manipulations (catheters/tubes), prior treatment with 3rd
generation cephalosporin.
 Treatment options: cefepime or piperacillin/tazobactam (although
some ESBL show resistance), carbapenems, tigecycline (not for
Pseudomonas).
C) How to reduce prevalence:



Meticulous hand washing, using alcohol based gels, wear gloves and
gowns when indicated.
Prompt de-escalation of antibiotics if patient clinically improved and ID
and sensitivity of organism available.
Consider stopping all antibiotics in a patient who is clinically improved
after 48 hours, and no organism isolated (assuming cultures drawn off
antibiotics).
Review Questions:
1) 73 yo diabetic male with h/o bilateral AKAs due to diabetic leg infections, B
ureteral stents, and multiple UTIs over the last 3 years presents to the ER with 3
day h/o fevers/rigors, and increased urinary frequency and pain. Patient was last
treated for a UTI two months ago, and completed a 10 day course of oral
ciprofloxacin. Urine cultures were not drawn at that time, but patient stated he had
improvement in symptoms. Exam in ER is notable for T 39 C, bp 100/50 (usual
BP 130s/80s), p 110, rr 12; rest of exam is notable only for mild suprapubic
tenderness, and GU/prostate exam wnl. Labs notable for elevated wbc at 12,000,
creatinine 1.8; UA positive for nitrites, large LE, many bacteria, TNTC WBC
with clumps. Blood cultures are drawn. Patient is started empirically on oral
ciprofloxacin and IVFs, and 24 hours later patient is feeling a little better, and
results of his urine culture come back, showing:
URINE CULTURE RESULTS: >100,000 CFU/mL KLEBSIELLA SP
Comment: Klebsiella pneumoniae
ANTIBIOTIC SUSCEPTIBILITY TEST RESULTS:
KLEBSIELLA SP
:
AMIKACIN
R
AMPICILLIN
R
AMPICILLIN/SUL R
CEFAZOLIN
R
CEFOTAXIME
S
CEFTIZOXIME
S
CEFTRIAXONE
I
CEFUROXIME
R
CIPROFLOXACIN R
GENTAMICIN
R
IMIPENEM
S
NITROFURANTOIN I
PIPERACILLIN/T R
PIPERACILLIN
R
TRIMETH/SULFA R
What is the next appropriate management step?
A) Continue oral ciprofloxacin for 7 days because patient is improving clinically.
B) Continue oral ciprofloxacin for 14 days because he has a complicated UTI due to
presence of stents.
C) Stop ciprofloxacin, start cefotaxime IV, and continue for 14 days due to presence of
stents.
D) Stop ciprofloxacin, start high dose oral nitrofurantoin, and complete 21 day course of
therapy.
E) Stop ciprofloxacin, start IV imipenem, put patient on contact precautions, and
complete a 14 day course of therapy.
2) 38 yo male with HIV/AIDs, last cd4 ct 55, is admitted to the hospital with fever,
headache. He has a vesicular rash over his trunk that covers multiple dermatomes, and he
states new lesions are appearing every day. He denies cough, and his CXR is clear. He is
admitted for workup of meningitis, and is also given a diagnosis of disseminated herpes
zoster.
Which isolation precautions would you order for this patient?
a) Airborne isolation
b) Contact isolation
c) Droplet isolation
d) Standard isolation
e) Droplet and contact isolation
f) Airborne and contact isolation
Correct answer is F – disseminated herpes zoster (from varicella virus) can be spread by
contact and small droplet nuclei – health care workers need to wear gloves, and gowns
with substantial contact. Patient should be placed in a negative air pressure room, with
N95 masks available for healthcare workers.
Post Module Evaluation
Please place completed evaluation in an interdepartmental mail envelope and address to
Dr. Wendy Gerstein, Department of Medicine, VAMC (111).
1) Topic of module:__________________________
2) On a scale of 1-5, how effective was this module for learning this topic? _________
(1= not effective at all, 5 = extremely effective)
3) Were there any obvious errors, confusing data, or omissions? Please list/comment
below:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
4) Was the attending involved in the teaching of this module? Yes/no (please circle).
5) Please provide any further comments/feedback about this module, or the inpatient
curriculum in general:
6) Please circle one:
Attending
Resident (R2/R3)
Intern
Medical student