16. Resistance Enterococcus
Antibiotic Resistance
mechanism
Label Alternate
antibiotics
Ampicillin Decreased
binding of
antibiotic
(chromosomal)
Ampicillin
resistant
Ampicillin and
aminoglycoside
Aminoglycoside
s
Aminoglycoside-
modifying
enzyme
(chromosomal)
High-level
(aminoglycoside
) resistant (HLR)
Vancomycin
Vancomycin Reduced
binding of drug
to cell wall
(plasmid)
VRE
•?
17. Resistance Gram Negative Bacilli
Antibiotic Resistance
mechanism
Label Alternate
antibiotics
Penicillins, 1st,
2nd and 3rd
generation
cephalosporins
and aztreonam
Extended-
spectrum β –
lactamases
Chromosomal
or plasmid
•Also frequently
resistant to:
fluoroquinolones
, co-trimoxazole,
trimethoprim
ESBL-producing - Carbapenems
Carbapenems Carbapenemas
e
•Transposon
(mobile genetic
material)
CRE
(Carbapenem
resistant
enterobacteriace
ae)
•? / Colistin
and Polymyxin
B
17
18. Types of Infections Caused by
MDROs
Gram (+) Cocci
Mandell, 7th Edition
Bacteria Types of infections
Staphylococcus
aureus
•Surgical site infections (SSI)
•Central line-associated
bloodstream infections (CLABSI)
•Ventilator-associated pneumonias
(VAP)
•Bacteremia
•Osetomyelitis, septic arthritis
•Other organs …
19. Types of Infections Caused by
MDROs
Gram (+) Cocci (2)
Mandell, 7th Edition
Bacteria Types of infections
Enterococcus
species
•Bacteremia
•Catheter-associated urinary tract
infections (CAUTI)
•Intra-abdominal and pelvic
infections
•Neonatal infections
•Skin and soft tissue
20. Types of Infections Caused by
MDROs
Gram (-) Bacilli
Mandell, 7th Edition
Bacteria Types of infections
Pseudomonas
aeruginosa
•Bacteremia
•Acute pneumonia, chronic respiratory infections
•Bone and joint
•Ear, eye
•UTI
•Skin and soft tissue (e.g., burns)
Acinetobacter
species
•Pneumonia
•Bacteremia
•Cellulitis after surgery or trauma
Enterobacteriace
ae
Klebsiella species
Enterobacter sp
•UTI
•Neonatal bacteremia
•Sepsis and meningitis
•Pneumonia
•Wound and burn infections
•CLABSIs
21. Surveillance
http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline
• Routine clinical cultures (antibiograms)
– Detect emergence of new MDROs
– Facility- or unit- specific summary antimicrobial
susceptibility reports
• Monitor for changes
• MDRO incidence (new isolates per 1000 patient
days or per month)
– Monitor trends / evaluate impact of prevention
– Does not distinguish colonization from infection
• MDRO infection rates
– Requires clinical data
– Helpful in defining clinical impact
• Molecular typing
– Confirm clonal transmission
– Evaluate interventions in facility
22. Active Surveillance Cultures
http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline
• Prospective identification of colonized
persons
• Coupled with intervention can reduce
transmission
• Resource intensive
• Methods
– MRSA: nares > perirectal and wound
– VRE: stool, rectal or perirectal
– MDR-GNB: peri-rectal or rectal alone or in
combination with oropharyngeal,
endotracheal, inguinal, or wound
25. Bacterial Survival times on
hands
Bacteria Time
Acinetobacter
spp.
60 min
E. coli 6 min (mean)
Klebsiella spp 2 min (mean)
VRE 60 min
Pseudomonas
spp.
30 min; 180 in sputum
Rotavirus 16% survive 20 min;
28. Otter JA, et al. Infect Control Hosp Epidemiol 2011;32:687-699
TRANSMISSION MECHANISMS INVOLVING
THE SURFACE ENVIRONMENT
29. • High touch surfaces
• Low touch surfaces
• Inanimate objects
– Medical equipment
– Patient’s items
– Office items
– HCP’s personal
items
• Patient-care area
– More susceptible
patients
– Less susceptibile
Environmental surfaces in health
care settings
30. • Bed rails
• Bed surface
• Supply cart
• Over-bed table
• Call box/button
• Telephone
• Sink
• Bedside table/handle
• Chair
• Light switch
• Door knob
• IV pump control
• Ventilator control
panel
• Monitor touch screen
• Bathroom inner door knob
• Bathroom light swith
• Bathroom handrails
• Bathroom sink
• Toilet seat
• Toilet flush handle
Hulsage k., et al. Infect Control Hosp Epidemiol 2010 Aug;31(8):850-3
CDC Environmental Checklist for Monitoring Terminal Cleaning
High touch room surfaces
34. Hulsage k., et al. Infect Control Hosp Epidemiol 2010 Aug;31(8):850-3
Five surfaces were
defined as high-touch
surfaces:
• the bed rails
• the bed surface
• The supply cart
• the over-bed table
• the intravenous
pump
35. The hospital linens and the washing machine were highly contaminated with B.cereus,
which was also isolated from the intravenous fluid.
All of the contaminated linens were autoclaved, the washingmachine was cleaned with a
detergent, and hand hygiene was promoted among the hospital staff. The number of
patients per month that developed new B. cereus bacteremia rapidly decreased after
implementing these measures.
The source of this outbreak was B.cereus contamination of hospital linens, and
B.cereus was transmitted from the linens to patients via catheter infection.
Our findings demonstrated that bacterial contamination of hospital linens can cause
nosocomial bacteremia.
Thus, blood cultures that are positive for B. cereus should not be regarded as false
positives in the clinical setting.
37. Organisms
Duration of persistence
(range)
Acinetobacter spp. 3 days to 5 months
C.Difficile spore 5 months
Enterococcus spp. including VRE 5 days to > 46 months
Pseudomonas aeruginosa
6 hours-16 months
On dry floor 5 weeks
Serratia marcescens
3 days to 2 months
On dry floor 5 weeks
Staphylococcus aureus 7 days to 7 months
Kramer et al. BMC Infectious Diseases 2006 6:130
Wagenvoort et al. Hosp Infect, 77 (2011), pp. 282–283
Nosocomial pathogens can
survive on surfaces for long
period
41. Facility-level CRE prevention: After CRE-positive discovered
8 core measures facilities
1. Hand Hygiene
2. Contact precuation
3. Healthcare education
4. Use of device
5. Patient and staff cohorting
6. Laboratory notifcation
7. Antimicrobial stewardship
8. CRE screening
Editor's Notes
Alternate drugs sometimes used for resistant Staphylococcus aureus include:
Trimethoprim-sulfamethoxazole
Quinupristin – Dalfopristin
Tigecycline (modified tetracycline)
I vancomycin resistant: options include daptomycin + aminoglycoside + another active agent, ampicillin or doxycycline with rifampin, linezolid + another active agent or high dose ampicillin + imipenem …
(Aminopenicillins, such as ticarcillin and piperacillin; quinolones, etc.)
Colistin and Polymyxin B were discovered in 1947. After 1980, they fell into disuse because of their nephrotoxicity. They are now being used as first line drugs against suspected gram negative infections in some parts of New York City because of the high degree of resistance.
Outbreaks of carbapenem-resistant, colistin resistant organisms have been reported in Detroit.
