Archive for July 13, 2013

Treatment of Acinetobacter infections.

Clin Infect Dis 2010 Jul 1; 51(1) :79-84.

Fishbain J, Peleg AY

Division of Infectious Diseases, St John Hospital and Medical Center, Detroit, Michigan 48236, USA.

Acinetobacter baumannii remains an important and difficult-to-treat pathogen whose resistance patterns result in significant challenges for the clinician. Despite the prevalence and interest in A. baumannii infections, there is relatively limited well-controlled scientific data to help the clinician select optimal empirical and subsequent targeted therapy for a variety of infections. We will review the currently available antimicrobial agents and discuss the clinical data supporting the use of the various agents.


July 13, 2013 at 3:23 pm

Acinetobacter baumannii: epidemiology, antimicrobial resistance, and treatment options.

Clin Infect Dis 2008 Apr 15; 46(8) :1254-63.

Maragakis LL, Perl TM

Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

Multidrug-resistant Acinetobacter baumannii is recognized to be among the most difficult antimicrobial-resistant gram-negative bacilli to control and treat. Increasing antimicrobial resistance among Acinetobacter isolates has been documented, although definitions of multidrug resistance vary in the literature. A. baumannii survives for prolonged periods under a wide range of environmental conditions. The organism causes outbreaks of infection and health care-associated infections, including bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection. Antimicrobial resistance greatly limits the therapeutic options for patients who are infected with this organism, especially if isolates are resistant to the carbapenem class of antimicrobial agents. Because therapeutic options are limited for multidrug-resistant Acinetobacter infection, the development or discovery of new therapies, well-controlled clinical trials of existing antimicrobial regimens and combinations, and greater emphasis on the prevention of health care-associated transmission of multidrug-resistant Acinetobacter infection are essential.


July 13, 2013 at 3:22 pm

In vitro activities of various antimicrobials alone and in combination with tigecycline against carbapenem-intermediate or -resistant Acinetobacter baumannii.

Antimicrob Agents Chemother 2007 May; 51(5) :1621-6.

Scheetz MH, Qi C, Warren JR, et al.

Department of Pharmacy, Northwestern Memorial Hospital, Feinberg Pavilion LC-700, Chicago, IL 60611, USA.

The activities of tigecycline alone and in combination with other antimicrobials are not well defined for carbapenem-intermediate or -resistant Acinetobacter baumannii (CIRA). Pharmacodynamic activity is even less well defined when clinically achievable serum concentrations are considered. Antimicrobial susceptibility testing of clinical CIRA isolates from 2001 to 2005 was performed by broth or agar dilution, as appropriate. Tigecycline concentrations were serially increased in time-kill studies with a representative of the most prevalent carbapenem-resistant clone (strain AA557; imipenem MIC, 64 mg/liter). The in vitro susceptibility of the strain was tested by time-kill studies in duplicate against the average free serum steady-state concentrations of tigecycline alone and in combination with various antimicrobials. Ninety-three CIRA isolates were tested and were found to have the following antimicrobial susceptibility profiles: tigecycline, MIC(50) of 1 mg/liter and MIC(90) of 2 mg/liter; minocycline, MIC(50) of 0.5 mg/liter and MIC(90) of 8 mg/liter; doxycycline, MIC(50) of 2 mg/liter and MIC(90) of > or =32 mg/liter; ampicillin-sulbactam, MIC(50) of 48 mg/liter and MIC(90) of 96 mg/liter; ciprofloxacin, MIC(50) of > or =16 mg/liter and MIC(90) of > or =16 mg/liter; rifampin, MIC(50) of 4 mg/liter and MIC(90) of 8 mg/liter; polymyxin B, MIC(50) of 1 mg/liter and MIC(90) of 1 mg/liter; amikacin, MIC(50) of 32 mg/liter and MIC(90) of > or =32 mg/liter; meropenem, MIC(50) of 16 mg/liter and MIC(90) of > or =128 mg/liter; and imipenem, MIC(50) of 4 mg/liter and MIC(90) of 64 mg/liter. Among the tetracyclines, the isolates were more susceptible to tigecycline than minocycline and doxycycline, according to FDA breakpoints (95%, 88%, and 71% of the isolates were susceptible to tigecycline, minocycline, and doxycycline, respectively). Concentration escalation studies with tigecycline revealed a maximal killing effect near the MIC, with no additional extent or rate of killing at concentrations 2x to 4x the MIC for tigecycline. Time-kill studies demonstrated indifference for tigecycline in combination with the antimicrobials tested. Polymyxin B, minocycline, and tigecycline are the most active antimicrobials in vitro against CIRA. Concentration escalation studies demonstrate that tigecycline may need to approach concentrations higher than those currently achieved in the bloodstream to adequately treat CIRA bloodstream infections. Future studies should evaluate these findings in vivo.


July 13, 2013 at 3:20 pm

Nebulized colistin in the treatment of pneumonia due to multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa.

Clin Infect Dis 2005 Sep 1; 41(5) :754-7.

Kwa AL, Loh C, Low JG, et al.

Division of Infectious Diseases, Department of Pharmacy, Singapore General Hospital, Singapore.

Twenty-one patients with multidrug-resistant (MDR) Acinetobacter baumannii and Pseudomonas aeruginosa pneumonia were treated with nebulized polymyxin E (colistin). Overall clinical and microbiological response rates were 57.1% and 85.7%, respectively. Nebulized colistin may be reasonably efficacious and safe for treatment of MDR pneumonia. Its role in therapy warrants further investigation in comparative studies.


July 13, 2013 at 3:19 pm

Bactericidal effects of 405 nm light exposure demonstrated by inactivation of Escherichia, Salmonella, Shigella, Listeria, and Mycobacterium species in liquid suspensions and on exposed surfaces.

ScientificWorldJournal. 2012;2012:137805.

Murdoch LE, Maclean M, Endarko E, MacGregor SJ, Anderson JG.


The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic and Electrical Engineering, University of Strathclyde-Glasgow, Glasgow G1 1XW, UK.


The bactericidal effect of 405 nm light was investigated on taxonomically diverse bacterial pathogens from the genera Salmonella, Shigella, Escherichia, Listeria, and Mycobacterium. High-intensity 405 nm light, generated from an array of 405-nm light-emitting diodes (LEDs), was used to inactivate bacteria in liquid suspension and on exposed surfaces. L. monocytogenes was most readily inactivated in suspension, whereas S. enterica was most resistant. In surface exposure tests, L. monocytogenes was more susceptible than Gram-negative enteric bacteria to 405 nm light when exposed on an agar surface but interestingly less susceptible than S. enterica after drying onto PVC and acrylic surfaces. The study findings, that 405 nm light inactivates diverse types of bacteria in liquids and on surfaces, in addition to the safety advantages of this visible (non-UV wavelength) light, indicate the potential of this technology for a range of decontamination applications.


July 13, 2013 at 3:17 pm

Evaluation of a hand-held far-ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens.

BMC Infect Dis. 2012 May 16;12:120.

Nerandzic MM, Cadnum JL, Eckart KE, Donskey CJ.


Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, USA.



Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe and rapid. The Sterilray™ Disinfection Wand device is a hand-held room decontamination technology that utilizes far-ultraviolet radiation (185-230 nm) to kill pathogens.


We examined the efficacy of disinfection using the Sterilray device in the laboratory, in rooms of hospitalized patients, and on surfaces outside of patient rooms (i.e. keyboards and portable medical equipment). Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly-touched surfaces before and after use of the Sterilray device.


On inoculated surfaces in the laboratory, application of the Sterilray device at a radiant dose of 100 mJ/cm(2) for ~ 5 seconds consistently reduced recovery of C. difficile spores by 4.4 CFU log10, MRSA by 5.4 log(10)CFU and of VRE by 6.9 log10CFU. A >3 log10 reduction of MRSA and VRE was achieved in ~2 seconds at a lower radiant dose, but killing of C. difficile spores was significantly reduced. On keyboards and portable medical equipment that were inoculated with C. difficile spores, application of the Sterilray device at a radiant dose of 100 mJ/cm(2) for ~ 5 seconds reduced contamination by 3.2 log10CFU. However, the presence of organic material reduced the lethal effect of the far-UV radiation. In hospital rooms that were not pre-cleaned, disinfection with the Sterilray device significantly reduced the frequency of positive C. difficile and MRSA cultures (P =0.007).


The Sterilray™ Disinfection Wand is a novel environmental disinfection technology that rapidly kills C. difficile spores and other healthcare-associated pathogens on surfaces. However, the presence of organic matter reduces the efficacy of far-UV radiation, possibly explaining the more modest results observed on surfaces in hospital rooms that were not pre-cleaned.


July 13, 2013 at 3:16 pm


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