Archive for September, 2014

Ebola virus disease in West Africa — the first 9 months of the epidemic and forward projections

N Engl J Med 2014 Sep 23

WHO Ebola Response Team.

BACKGROUND

On March 23, 2014, the World Health Organization (WHO) was notified of an outbreak of Ebola virus disease (EVD) in Guinea. On August 8, the WHO declared the epidemic to be a “public health emergency of international concern.”

METHODS

By September 14, 2014, a total of 4507 probable and confirmed cases, including 2296 deaths from EVD (Zaire species) had been reported from five countries in West Africa — Guinea, Liberia, Nigeria, Senegal, and Sierra Leone. We analyzed a detailed subset of data on 3343 confirmed and 667 probable Ebola cases collected in Guinea, Liberia, Nigeria, and Sierra Leone as of September 14.

RESULTS

The majority of patients are 15 to 44 years of age (49.9% male), and we estimate that the case fatality rate is 70.8% (95% confidence interval [CI], 69 to 73) among persons with known clinical outcome of infection. The course of infection, including signs and symptoms, incubation period (11.4 days), and serial interval (15.3 days), is similar to that reported in previous outbreaks of EVD. On the basis of the initial periods of exponential growth, the estimated basic reproduction numbers (R0 ) are 1.71 (95% CI, 1.44 to 2.01) for Guinea, 1.83 (95% CI, 1.72 to 1.94) for Liberia, and 2.02 (95% CI, 1.79 to 2.26) for Sierra Leone. The estimated current reproduction numbers (R) are 1.81 (95% CI, 1.60 to 2.03) for Guinea, 1.51 (95% CI, 1.41 to 1.60) for Liberia, and 1.38 (95% CI, 1.27 to 1.51) for Sierra Leone; the corresponding doubling times are 15.7 days (95% CI, 12.9 to 20.3) for Guinea, 23.6 days (95% CI, 20.2 to 28.2) for Liberia, and 30.2 days (95% CI, 23.6 to 42.3) for Sierra Leone. Assuming no change in the control measures for this epidemic, by November 2, 2014, the cumulative reported numbers of confirmed and probable cases are predicted to be 5740 in Guinea, 9890 in Liberia, and 5000 in Sierra Leone, exceeding 20,000 in total.

CONCLUSIONS

These data indicate that without drastic improvements in control measures, the numbers of cases of and deaths from EVD are expected to continue increasing from hundreds to thousands per week in the coming months.

PDF

http://www.nejm.org/doi/pdf/10.1056/NEJMoa1411100

September 25, 2014 at 3:52 pm

The Ebola emergency — immediate action, ongoing strategy.

N Engl J Med 2014 Sep 23

Farrar JJ and Piot P

The 25th known outbreak of Ebola virus infection is unlike any of the previous epidemics. It has already killed over 2800 people — more than all previous epidemics combined; it’s affecting virtually the entire territory of three countries, involving rural areas, major urban centers, and capital cities; it has been going on for almost a year; and it is occurring in West Africa, where no Ebola outbreak had previously occurred.

Above all, the epidemic seems out of control and has evolved into a major humanitarian crisis that has finally mobilized the world, with responses ranging from an emergency health mission launched by the United Nations Security Council to proposed military-style interventions and the global provision of emergency aid….

PDF

http://www.nejm.org/doi/pdf/10.1056/NEJMe1411471

 

September 25, 2014 at 3:51 pm

Alternative Screening Approaches for Discovery of Middle East Respiratory Syndrome Coronavirus Inhibitors

Antimicrobial Agents and Chemotherapy AUG  2014 V.58 N.8 P.4251-4252

Robert L. LaFemina

Editor, Antimicrobial Agents and Chemotherapy, Schwenksville, Pennsylvania, USA

Two coronaviruses causing severe respiratory disease and high mortality rates emerging within the past dozen years reinforces the need for clinically efficacious antivirals targeting coronaviruses.

Alternative screening approaches for antivirals against the recently emergent Middle East respiratory syndrome coronavirus (MERS-CoV) may provide lead compounds to address this need.

Two Antimicrobial Agents and Chemotherapy (AAC) papers screened libraries of approved compounds that may potentially be repurposed as MERS-CoV antivirals.

A third AAC paper showed that a previously described severe acute respiratory syndrome coronavirus (SARS-CoV) helicase inhibitor also has activity against MERS-CoV.

PDF

http://aac.asm.org/content/58/8/4251.full.pdf+html

September 24, 2014 at 8:16 pm

Effectiveness of Antimicrobial Peptide Immobilization for Preventing Perioperative Cornea Implant-Associated Bacterial Infection

Antimicrobial Agents and Chemotherapy Sept 2014 V.58 N.9 P.5229-5238

Xiao Wei Tana, Tze Wei Goha, P. Saraswathib, Chan Lwin Nyeina, Melina Setiawana, Andri Riaua, R. Lakshminarayananb,e, Shouping Liub,e, Donald Tanc,d,e, Roger W. Beuermanb,c,f and Jodhbir S. Mehtaa,b,d,e

aTissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore

bAntimicrobials Group, Singapore Eye Research Institute, Singapore

cYong Loo Lin School of Medicine, National University of Singapore, Singapore

dSingapore National Eye Centre, Singapore

eDuke-NUS Graduate Medical School, Singapore

fDuke-NUS SRP Neuroscience and Behavioral Disorders, Singapore

Titanium (Ti) is a promising candidate biomaterial for an artificial corneal skirt. Antimicrobial peptide (AMP) immobilization may improve the bactericidal effect of the Ti substrate.

In this study, we tested the bactericidal efficacy of a functionalized Ti surface in a rabbit keratitis model. A corneal stromal pocket was created by a femtosecond laser.

The Ti films were then inserted into the pocket, and Staphylococcus aureus or Pseudomonas aeruginosa was inoculated into the pocket above the implant films.

The corneas with Ti-AMP implants were compared with the corneas implanted with unprotected Ti by slit lamp observation and anterior segment optical coherence tomography (AS-OCT). Inflammatory responses were evaluated by bacterium counting, hematoxylin-eosin staining, and immunostaining.

There was a lower incidence and a lesser extent of infection on rabbit corneas with Ti-AMP implants than on those with unprotected Ti implants.

The bactericidal effect of AMP against S. aureus was comparable to that of postoperative prophylactic antibiotic treatment; hence, SESB2V AMP bound to the Ti implant provided functional activity in vivo, but its efficacy was greater against S. aureus than against P. aeruginosa.

This work suggests that SESB2V AMP can be successfully functionalized in a rabbit keratitis model to prevent perioperative corneal infection.

PDF

http://aac.asm.org/content/58/9/5229.full.pdf+html

September 24, 2014 at 8:14 pm

Revised Reference Broth Microdilution Method for Testing Telavancin: Effect on MIC Results and Correlation with Other Testing Methodologies

Antimicrobial Agents and Chemotherapy Sept 2014 V.58 N.9 P.5547-5551

David J. Farrell, Rodrigo E. Mendes, Paul R. Rhomberg and Ronald N. Jones

JMI Laboratories, North Liberty, Iowa, USA

The reference broth microdilution (BMD) antimicrobial susceptibility testing method for telavancin was revised to include dimethyl sulfoxide (DMSO) as a solvent and diluent for frozen-form panel preparation, following the CLSI recommendations for water-insoluble agents.

Polysorbate 80 (P-80) was also added to the test medium to minimize proven drug losses associated with binding to plastic surfaces.

Four hundred sixty-two Gram-positive isolates, including a challenge set of organisms with reduced susceptibilities to comparator agents, were selected and tested using the revised method for telavancin, and the MIC results were compared with those tested by the previously established method and several Sensititre dry-form BMD panel formulations.

The revised method provided MIC results 2- to 8-fold lower than the previous method when tested against staphylococci and enterococci, resulting in MIC50 values of 0.03 to 0.06 μg/ml for staphylococci and 0.03 and 0.12 μg/ml for Enterococcus faecium and Enterococcus faecalis, respectively.

Less-significant MIC decreases (1 to 2 log2 dilution steps) were observed when testing streptococci in broth supplemented with blood, which showed similar MIC50 values for both methods.

However, Streptococcus pneumoniae had MIC50 results of 0.008 and 0.03 μg/ml when tested by the revised and previous methods, respectively.

Highest essential agreement rates (≥94.0%) were noted for one candidate dry-form panel formulation compared to the revised test. The revised BMD method provides lower MIC results for telavancin, especially when tested against staphylococci and enterococci.

This is secondary to the use of DMSO for panel production and the presence of P-80, which ensure the proper telavancin testing concentration and result in a more accurate MIC determination.

Moreover, earlier studies where the previous method was applied underestimated the in vitro drug potency.

PDF

http://aac.asm.org/content/58/9/5547.full.pdf+html

September 24, 2014 at 8:12 pm

Antimicrobial activity of a novel adhesive containing chlorhexidine gluconate (CHG) against the resident microflora in human volunteers

Journal of Antimicrobial Chemotherapy AUG 2014 V.69 N.8 P.2224-2229

Neal Carty1,*, Anne Wibaux1, Colleen Ward1, Daryl S. Paulson2 and Peter Johnson1

1Vancive Medical Technologies™, 20 N. Wacker Drive Suite 2240, Chicago, IL 60606, USA

2BioScience Laboratories, Inc., 1765 S. 19th Avenue, Bozeman, MT 59718, USA

*Corresponding author. Tel: +1-440-534-3515; Fax: +1 440 534 2955; E-mail: neal.carty@averydennison.com

Objectives

To evaluate the antimicrobial activity of a new, transparent composite film dressing, whose adhesive contains chlorhexidine gluconate (CHG), against the native microflora present on human skin.

Methods

CHG-containing adhesive film dressings and non-antimicrobial control film dressings were applied to the skin on the backs of healthy human volunteers without antiseptic preparation. Dressings were removed 1, 4 or 7 days after application. The bacterial populations underneath were measured by quantitative cultures (cylinder-scrub technique) and compared with one another as a function of time.

Results

The mean baseline microflora recovery was 3.24 log10 cfu/cm2. The mean log reductions from baseline measured from underneath the CHG-containing dressings were 0.87, 0.78 and 1.30 log10 cfu/cm2 on days 1, 4 and 7, respectively, compared with log reductions of 0.67, −0.87 and −1.29 log10 cfu/cm2 from underneath the control film dressings. There was no significant difference between the log reductions of the two treatments on day 1, but on days 4 and 7 the log reduction associated with the CHG adhesive was significantly higher than that associated with the control adhesive.

Conclusions

The adhesive containing CHG was associated with a sustained antimicrobial effect that was not present in the control. Incorporating the antimicrobial into the adhesive layer confers upon it bactericidal properties in marked contrast to the non-antimicrobial adhesive, which contributed to bacterial proliferation when the wear time was ≥4 days.

PDF

http://jac.oxfordjournals.org/content/69/8/2224.full.pdf+html

September 22, 2014 at 2:41 pm

Pitfalls in evidence assessment: the case of chlorhexidine and alcohol in skin antisepsis

Journal of Antimicrobial Chemotherapy AUG 2014 V.69 N.8 P.2017-2021

Matthias Maiwald1,2,3,* and Edwin S.-Y. Chan3,4,5

1Department of Pathology and Laboratory Medicine, KK Women’s and Children’s Hospital, Singapore

2Department of Microbiology, National University of Singapore, Singapore

3Duke-NUS Graduate Medical School, Singapore

4Singapore Clinical Research Institute, Singapore

5Singapore Branch, Australasian Cochrane Centre, Singapore

*Corresponding author. Department of Pathology and Laboratory Medicine, KK Women’s and Children’s Hospital, 100 Bukit Timah Road, Singapore 229899, Singapore. Tel: +65 6394 8725; Fax: +65 6394 1387; E-mail: matthias.maiwald@kkh.com.sg

Chlorhexidine has attracted increasing attention for its role in skin antisepsis in recent years.

It was tested in several prominent clinical trials and subsequently recommended in important guidelines for blood culture collection, vascular catheter insertion and surgical skin preparation.

We noticed and subsequently reported a widespread misinterpretation of evidence surrounding chlorhexidine and its role in skin antisepsis.

Multiple clinical trial reports and systematic reviews that had assessed the clinical efficacy of chlorhexidine/alcohol combinations for skin antisepsis had attributed efficacy solely to the chlorhexidine component.

This misinterpretation was carried over into the tertiary literature, including evidence-based guidelines.

Here we discuss some of the scientific, ethical, patient safety and infection control implications of this misinterpretation, as well as broader implications for evidence-based medicine.

PDF

http://jac.oxfordjournals.org/content/69/8/2017.full.pdf+html

September 22, 2014 at 2:37 pm

Older Posts Newer Posts


Calendar

September 2014
M T W T F S S
1234567
891011121314
15161718192021
22232425262728
2930  

Posts by Month

Posts by Category