The organisms below were isolated and demonstrated antimicrobial sensitivities as listed.
Enterococcus faecalis
|
Drug |
Sensitivity |
|
Ampicillin |
R |
|
Chlorampenicol |
R |
|
Ciproflxacin |
R |
|
Erythromycin |
R |
|
Gentamicin |
R |
|
Nitrofurantoin |
R |
|
Cotrimoxazole |
R |
|
Teicoplanin |
R |
|
Vancomycin |
R |
Klebsiella pneumoniae
|
Drug |
MIC (µg/ml) |
|
Cefpodoxime |
≥ 2 |
|
Ceftazidime |
≥ 2 |
|
Aztreonam |
≥ 2 |
|
Cefotaxime |
≥ 2 |
|
Ceftriaxone |
≥ 2 |
a) What is the significance of these results?
b) List 1 appropriate antimicrobial in each case.
c) List the strategies available to reduce the development of these organisms in ICUs.
Van A VRE
Linezolid, Daptomycin, (Tigecycline, Quinupristin-dalfopristin)
ESBL
Carbapenem (imipenem, meropenem, and perhaps ertapenem), Colistin, Aminoglycosides, Ciprofloxacin
c) List the strategies available to reduce the development of these organisms in ICUs.
Strategies to improve the efficacy and utilization of antimicrobial therapy
• Antibiotic evaluation committees
• Protocols and guidelines to promote appropriate antimicrobial utilization
• Hospital formulary restrictions of broad-spectrum agents
• Substitution of narrow-spectrum antibiotics (such as first generation cephalosporins and aminoglycosides)
• Mandatory consultations with infectious diseases specialists
• Antibiotic cycling by regularly cycling different antimicrobial classes
Infection control measures
• Handwashing compliance: Alcohol-based hand wash is more effective than traditional soap and water in cleansing hands of bacteria
• Barrier precautions with gloves and gowns
• Isolation
• Surveillance for multidrug-resistant bacteria for the early identification and control
• Monitoring and disseminating the incidence and prevalence of isolation of multidrug-resistant bacteria
• Limiting LOS and invasive devices (idc / ett/ vascular)
a) The Enterococcus is a VRE, and the Klebsiella possesses a β-lactamase which seems to lyse extended spectrum cephalosporins, which makes it an ESBL organism.
b) The Enterococcus can be managed with linezolid, tigecycline or daptomycin.
The Klebsiella may still be sensitive to carbapenems and it may still be somewhat susceptible to extended spectrum β-lactams (such as Tazocin), but if all else fails there are always amikacin and colistin up your sleeve.
c) Strategies for the prevention and spread of multi-resistant organisms?
A CICM trainee should be able to issue forth a torrential stream of evidence-based antibiotic stewardship strategies and infection control protocols.
Prevent emergence of antibiotic resistance:
According to a 2011 review, antimicrobial stewardship interventions beyond 6 months were associated with reductions in antimicrobial resistance rates, which suggests that the above strategies can be rapidly effective.
Prevent cross-contamination:
Gniadkowski, M. "Evolution and epidemiology of extended‐spectrum β-lactamases (ESBLs) and ESBL‐producing microorganisms." Clinical microbiology and infection 7.11 (2001): 597-608.
Huskins, W. Charles, et al. "Intervention to reduce transmission of resistant bacteria in intensive care." New England Journal of Medicine 364.15 (2011): 1407-1418.
Kollef, Marin H., and Victoria J. Fraser. "Antibiotic resistance in the intensive care unit." Annals of internal medicine 134.4 (2001): 298-314.
Kaki, Reham, et al. "Impact of antimicrobial stewardship in critical care: a systematic review." Journal of antimicrobial chemotherapy 66.6 (2011): 1223-1230.