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Infectious Diseases in Clinical Practice:
doi: 10.1097/IPC.0b013e31824a8d9c
IDCP Snapshots

Snapshots From 2011 Infectious Diseases Society of America (IDSA, Boston, October 19–23, 2011)

Saravolatz, Louis D. MD, MACP, FIDSA

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From the Department of Medicine, St. John Hospital & Medical Center, Wayne State University School of Medicine, Detroit, MI.

Correspondence to: Louis D. Saravolatz, MD, MACP, FIDSA, Department of Medicine, St. John Hospital & Medical Center, Wayne State University School of Medicine, Detroit, MI. E-mail:

The author has no funding or conflicts of interest to disclose.

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This was a retrospective evaluation of the 30-day mortality of 300 adult patients treated for Clostridium difficile infection (CDI) with metronidazole from two different periods, November 2005–August 2006 and October 2009–January 2011. Patient data collected included length of stay, duration of treatment, comorbidities, relapses, and 30-day all-cause mortality. Relapses were defined as diarrhea and positive stool antigen assay up to 8 weeks after completion of previous treatment. Patients were defined as mild/moderate or severe using the severity scoring system provided in the Infectious Diseases Society of America/Society for Healthcare Epidemiology of America (IDSA/SHEA) guidelines (Cohen et al., Infection Control and Hospital Epidemiology, 2010). Among the 285 patients evaluable for severity who were treated with metronidazole for CDI, 138 (48.4%) were defined as mild/moderate and 147 (51.6%) as severe disease. There were no differences between patients with mild and severe disease with respect to age, gender, length of stay, or recent antibiotic use. There was a significantly higher 30-day all-cause mortality in those with severe versus mild/moderate disease (32% vs. 16.7%, P = 0.002). An elevated modified Charlson score was seen in patients who died within 30 days compared with those in survivors (3.8 ± 2.7 vs 2.5 ± 2.0, P = 0.002). From logistic regression, both severe CDI and an elevated Charlson score remained significant predictors of 30-day all-cause mortality. The use of metronidazole in patients with severe CDI as defined by the IDSA/SHEA guidelines is associated with increased risk of 30-day all-cause mortality even after controlling for underlying comorbidities.

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The authors presented their study and also showed at the meeting that compliance with guideline recommendations was not adhered to in 45% of patients both before and after guideline availability at a community teaching hospital. This article reinforces the importance of the IDSA/SHEA clinical practice guidelines for the use of a severity scoring system for guiding therapy. Patients with more severe diseases often did not receive recommended therapy. There is a need to continue to reinforce these guidelines and hopefully, with more time, there will be better adherence to these guidelines to provide optimal therapy.

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A cluster-randomized, double-blind, controlled trial comparing the effectiveness of thrice-weekly chlorhexidine (CHG) cloths with control in skin infection prevention was conducted among military recruits. Baseline and serial nasal/axillary swabs were assessed for community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) colonization. Isolates were typed by pulsed field gel electrophoresis. Of the 1562 subjects enrolled, 32 (2.0%) were colonized with CA-MRSA at baseline, primarily with pulsed field gel electrophoresis types USA800 (31%), USA100 (25%), USA1000 (16%), and USA300 (13%). After 10 weeks, the CHG group had 68 follow-up CA-MRSA colonization episodes that included types USA800 (51.5%), USA100 (23.5%), USA300 (13.2%). In contrast, the control group had 99 CA-MRSA colonization episodes that included types USA300 (40.4%), USA800 (38.4%), USA1000 (12.1%), and USA100 (6.1%). The mean cumulative incidence of USA300 colonization was lower in the CHG group than in the control group (0.9% vs 3.6%, P = 0.058). Use of CHG caused a trend toward decreased acquisition of CA-MRSA type USA300 in military recruits. Furthermore, increased colonization with less virulent types, namely USA800, was observed over time.

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This is an important epidemiology study showing the dynamics of MRSA colonization in a military population. Although USA300 is the predominant community strain today, other types including USA800 may become more dominant in the future. We need to be cautious about assuming that USA800 will maintain its “less virulent” profile in the future. There were too few cases of infection to determine the effectiveness of CHG in this study. Chlorhexidine again seems to be an effective agent in reducing rates of colonization and potentially infection, however, widespread use may lead to reduced effectiveness of this agent in the future.

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Enterobacteriaceae carrying the New Delhi metallo-β-lactamase-1 enzyme (NDM-1) are rare in North America and are associated with medical care in South Asia. A patient was transferred to a US community hospital with tracheostomy aspirate that grew an NDM-1–producing Klebsiella pneumoniae and pan-resistant strains of Acinetobacter spp and Pseudomonas aeruginosa. The patient was placed in a private room on contact isolation, with 1:1 nursing, and infection prevention education was provided. To determine if nosocomial transmission or environmental contamination occurred, perirectal areas and wounds were cultured in all patients in proximity to the index patient. Tracheostomy aspirates were obtained from patients throughout the hospital who shared the index patient’s respiratory therapists. Serial environmental cultures were obtained from his room. Perirectal, wound, stool, urine, and tracheal cultures were obtained from the patient to determine the duration of colonization. Patient care areas were cleaned and disinfected with vaporized hydrogen peroxide. Twenty-four rectal swabs, 6 tracheal aspirates, and 2 wound cultures were obtained from 24 patients. A total of 35 environmental swabs were obtained. None of these cultures grew NDM-1–producing organisms. Fourteen surveillance cultures were obtained from the index case. The patient was intermittently colonized with the NDM-1 K. pneumoniae from stool and tracheal aspirates for more than 4 months. Interestingly, surveillance cultures revealed an NDM-1 Salmonella senftenberg from a rectal swab. The patient received rifaximin for 12 days, and the first postdecolonization stool culture did not grow Salmonella. The NDM-1–producing Enterobacteriaceae are of concern because of limited treatment options. The authors demonstrated that management consisting of rapid identification of a patient with the relevant epidemiological risk factors, education of the staff, immediate contact isolation in a private room, 1:1 nursing care, and aggressive cleaning and disinfection limited the environmental burden and prevented transmission of this organism.

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The authors demonstrate again that we practice in a global environment. Because of ease of travel, when a serious infectious disease, such as NDM-1, occurs in one part of the world, we are all threatened. This organism has been reported from countries other than India, including Pakistan, the United Kingdom, the United States, Canada, Japan, and Brazil. Fortunately, the careful vigilance and basic infection prevention measures used by these authors were successful in containing this organism. This pathogen’s susceptibility to a few agents such as polymyxin and tigecycline makes it a serious problem that justifies heightened awareness and intense infection control efforts. From the study presented, it may be suggested that this organism is less transmissible than some other pathogens; however, we really do not want to take a chance when there are so few agents to be used in the treatment of the New Delhi strain.

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Although, in a 2009 survey, no antimicrobial agent with a purely gram-negative spectrum had reached phase 2, in the current survey, the authors found nine intravenous compounds active against resistant gram-negative bacilli in clinical development: one β-lactamase inhibitor combination in a phase 3 study of complicated urinary tract infections; six compounds in phase 2 studies of acute bacterial skin and skin structure infections (1), complicated urinary tract infections (4), and/or complicated intra-abdominal infections (3) (Table 1). In addition,some promising compounds are in phase 1 or preclinical development. The authors found no studies of health care–associated or ventilator-associated pneumonia. Only three compounds demonstrated a novel mechanism of action.

Table 1
Table 1
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This survey demonstrates tangible progress in the development of new drugs that target infections caused by resistant gram-negative bacilli.

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It is encouraging to see progress in the 10 × ’20 initiative of the Infectious Diseases Society of America. Although recent years have demonstrated progress in the approval of new agents for the treatment of gram-positive infections with agents such as telavancin and ceftaroline, we have yet to see a new agent approved with purely gram-negative activity. The combination of the global emergence of multidrug-resistant gram-negative organisms such as the ESKAPE (Enterococcus species, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp) pathogens and the slow process of antimicrobial development poses an ominous threat to the future success of antimicrobial therapy. There are many shortcomings in the process of antimicrobial development, and the process belongs to us all as a major public health threat to our society. We need creative approaches to facilitate this process not to block it. If we do not urgently address this need, we will fall short of our goal of 10 × ’20. Hopefully, all involved in antimicrobial development will make this a superurgent priority for our patients.

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1. A Venugopal, S Szpunar, R Sessions, L Johnson. A comparison of the outcomes of metronidazole-treated patients with Clostridium difficile infection (CDI) using the IDSA/SHEA clinical practice severity of illness guidelines. IDSA 2011; abstract 758.

2. T Whitman, C Schlett, G Grandits, et al. Longitudinal molecular epidemiology of methicillin-resistant Staphylococcus aureus isolates colonizing and infecting marine recruits. IDSA 2011; abstract 561.

3. R Gopinath, P Savard, B M Landrum, et al. Management of a New Delhi metallo-beta-lactamase-1 enzyme (NDM-1)–producing Klebsiella pneumoniae (KP): Infection control and medical implications. IDSA 2011; abstract 384.

4. H Boucher, D Gilbert, D Benjamin, et al. 10 × ’20 Progress: Development of new drugs active against resistant gram-negative bacilli. IDSA 2011; abstract LB-27.

© 2012 Lippincott Williams & Wilkins, Inc.

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