Archive for August, 2012

Vancomycin: a 50-something-year-old antibiotic we still don’t understand.

Cleve Clin J Med. 2011 Jul V.78  N.7  P.465-71.

Schilling A, Neuner E, Rehm SJ.

Department of Infectious Disease, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.

Abstract

Because a significant proportion of Staphylococcus aureus strains as well as most coagulase-negative staphylococci are resistant to penicillin and semisynthetic beta-lactam drugs, the need for vancomycin and related antibiotics has never been greater. Effective use of vancomycin requires knowledge of dosing parameters and selection of target trough levels appropriate to the specific infection and to the pathogen being treated. For clinicians, it is vital to remain up-to-date with evolving definitions for vancomycin susceptibility, with new interpretations of efficacy, and with information on toxicity.

PDF

http://www.ccjm.org/content/78/7/465.full.pdf+html

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August 28, 2012 at 9:24 pm

Clinical impact of a real-time PCR assay for rapid identification of staphylococcal bacteremia.

J Clin Microbiol. 2012 Jan V.50  N.1  P.127-33.

Frye AM, Baker CA, Rustvold DL, Heath KA, Hunt J, Leggett JE, Oethinger M.

Department of Pharmacy, Providence St. Vincent Medical Center, Portland, Oregon, USA. abigail.frye@providence.org

Abstract

The purpose of this study was to evaluate the impact of real-time PCR reporting both on timely identification of clustered Gram-positive cocci (GPC) in blood cultures and on appropriate antibiotic treatment. This retrospective, interventional cohort study evaluated inpatients with blood cultures positive for GPC in the pre-PCR (15 January 2009 to 14 January 2010) and post-PCR (15 January 2010 to 14 January 2011) periods. Post-PCR implementation, laboratory services completed batched PCR; results other than methicillin-resistant Staphylococcus aureus (MRSA) were reported in the electronic medical record without additional interventions. The assay’s sensitivity and specificity, time to identification of staphylococcal bacteremia, and clinically relevant outcomes, including time to optimal antibiotic therapy, were evaluated. Demographic information was also collected and analyzed. Sixty-eight and 58 patients with Staphylococcus aureus bacteremia from the pre- and post-PCR periods, respectively, met inclusion criteria. Similar numbers of consecutive patients with coagulase-negative staphylococci were analyzed for comparison. The time to identification was significantly reduced post-PCR implementation (mean, 13.2 h; 95% confidence interval [95% CI], 10.5 to 15.9 h; P < 0.0001). However, the time to optimal antibiotic therapy was not significantly reduced. We conclude that implementation of a PCR assay demonstrated the potential to improve appropriate antibiotic use based on clinically meaningful and statistically significant reductions in the time to microbiologic identification. However, in order to realize this potential benefit, processes must be optimized and additional interventions initiated to facilitate providers’ use of the PCR result.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256728/pdf/zjm127.pdf

August 28, 2012 at 9:23 pm

Epidemic of invasive pneumococcal disease, western Canada, 2005-2009.

Emerg Infect Dis. 2012 May  V.18 N.5  P.733-40.

Tyrrell GJ, Lovgren M, Ibrahim Q, Garg S, Chui L, Boone TJ, Mangan C, Patrick DM, Hoang L, Horsman GB, Van Caeseele P, Marrie TJ.

Provincial Laboratory for Public Health (Microbiology) Edmonton, Alberta, Canada. greg.tyrrell@albertahealthservices.ca

Abstract

In Canada before 2005, large outbreaks of pneumococcal disease, including invasive pneumococcal disease caused by serotype 5, were rare. Since then, an epidemic of serotype 5 invasive pneumococcal disease was reported: 52 cases during 2005, 393 during 2006, 457 during 2007, 104 during 2008, and 42 during in 2009. Of these 1,048 cases, 1,043 (99.5%) occurred in the western provinces of Canada. Median patient age was 41 years, and most (659 [59.3%]) patients were male. Most frequently representing serotype 5 cases (compared with a subset of persons with non-serotype 5 cases) were persons who were of First Nations heritage or homeless. Restriction fragment-length polymorphism typing indicated that the epidemic was caused by a single clone, which multilocus sequence typing identified as sequence type 289. Large pneumococcal epidemics might go unrecognized without surveillance programs to document fluctuations in serotype prevalence.

FULL TEXT

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3358065/

August 28, 2012 at 9:22 pm

Pneumonia in healthy Canadian children and youth: Practice points for management.

Paediatr Child Health. 2011 Aug  V.16 N.7  P.417-24.

Le Saux N, Robinson J.

Abstract

Although immunization has decreased the incidence of bacterial pneumonia in vaccinated children, pneumonia remains common in healthy children. Unless it is totally impractical, a chest radiograph should be performed to confirm the diagnosis of pneumonia. Factors such as age, vital signs and other measures of illness severity are critical in the decision regarding whether to admit a patient to hospital. Because Streptococcus pneumoniae continues to be the most common cause of bacterial pneumonia in children, prescribing amoxicillin or ampicillin for seven to 10 days remains the mainstay of empirical therapy for non-severe pneumonia. If improvement does not occur, consideration should be given to searching for complications (empyema or lung abscess). Routine chest radiographs at the end of therapy are not recommended unless clinically indicated.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3200392/pdf/pch16417.pdf

August 27, 2012 at 8:28 am

Streptococcus pneumoniae serotype 19A in Latin America and the Caribbean: a systematic review and meta-analysis, 1990-2010.

BMC Infect Dis. 2012 May 28  V.12  N.1  P.124.

Castañeda E, Agudelo CI, De Antonio R, Rosselli D, Calderón C, Ortega-Barria E, Colindres RE.

ABSTRACT:

BACKGROUND:

Pneumococcal conjugate vaccines (PCVs) are in the process of implementation in Latin America. Experience in developed countries has shown that they reduce the incidence of invasive and non-invasive disease. However, there is evidence that the introduction of PCVs in universal mass vaccination programs, combined with inappropriate and extensive use of antibiotics, could be associated to changes in non-PCV serotypes, including serotype 19A. We conducted a systematic review to determine the distribution of serotype 19A, burden of pneumococcal disease and antibiotic resistance in the region.

METHODS:

We performed a systematic review of serotype 19A data from observational and randomized clinical studies in the region, conducted between 1990 and 2010, for children under 6 years. Pooled prevalence estimates from surveillance activities with confidence intervals were calculated.

RESULTS:

We included 100 studies in 22 countries and extracted data from 63. These data reported 19733 serotyped invasive pneumococcal isolates, 3.8% of which were serotype 19A. Serotype 19A isolates were responsible for 2.4% acute otitis media episodes, and accounted for 4.1% and 4.4% of 4,380 nasopharyngeal isolates from healthy children and in hospitalbased/ sick children, respectively. This serotype was stable over the twenty years of surveillance in the region. A total of 53.7% Spn19A isolates from meningitis cases and only 14% from non meningitis were resistant to penicillin.

CONCLUSIONS:

Before widespread PCV implementation in this region, serotype 19A was responsible for a relatively small number of pneumococcal disease cases. With increased use of PCVs and a greater number of serotypes included, monitoring S. pneumoniae serotype distribution will be essential for understanding the epidemiology of pneumococcal disease.

PDF

http://www.biomedcentral.com/content/pdf/1471-2334-12-124.pdf

August 27, 2012 at 8:26 am

Glycopeptide resistance in gram-positive cocci: a review.

Interdiscip Perspect Infect Dis. 2012 

Sujatha S, Praharaj I.

Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605006, India.

Abstract

Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens in the past two decades all over the world and have seriously limited the choices available to clinicians for treating infections caused by these agents. Methicillin-resistant Staphylococcus aureus, perhaps the most notorious among the nosocomial pathogens, was till recently susceptible to vancomycin and the other glycopeptides. Emergence of vancomycin nonsusceptible strains of S. aureus has led to a worrisome scenario where the options available for treating serious infections due to these organisms are very limited and not well evaluated. Vancomycin resistance in clinically significant isolates of coagulase-negative staphylococci is also on the rise in many setups. This paper aims to highlight the genetic basis of vancomycin resistance in Enterococcus species and S. aureus. It also focuses on important considerations in detection of vancomycin resistance in these gram-positive bacteria. The problem of glycopeptide resistance in clinical isolates of coagulase-negative staphylococci and the phenomenon of vancomycin tolerance seen in some strains of Streptococcus pneumoniae has also been discussed. Finally, therapeutic options available and being developed against these pathogens have also found a mention.

PDF

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3388329/pdf/IPID2012-781679.pdf

 

August 27, 2012 at 8:23 am

Should surgeons scrub with chlorhexidine or iodine prior to surgery?

Interact Cardiovasc Thorac Surg. 2011 Jun;12(6):1017-21.

Jarral OA, McCormack DJ, Ibrahim S, Shipolini AR.

Department of Cardiothoracic Surgery, The London Chest Hospital, Bonner Road, London E2 9JX, UK. omar.jarral01@imperial.ac.uk

Abstract

A best evidence topic was written according to a structured protocol. The question addressed was whether chlorhexidine gluconate is equivalent or superior to the use of povidone-iodine during surgical hand scrub. A total of 593 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. We conclude that whilst both chlorhexidine and povidone-iodine reduce bacterial count after scrubbing, the effect of chlorhexidine is both more profound and longer lasting. The studies found analysed the difference in reduction in colony forming units or bacterial count following surgical scrub in order to conclude that chlorhexidine was superior. Four studies went further to analyse cumulative and residual activity by testing for bacterial reduction after using a scrub solution for a number of days, an area in which chlorhexidine showed consistent advantages over povidone-iodine. These findings are given more credibility by the clinical finding of a recent meta-analysis of over 5000 patients in which chlorhexidine as an antiseptic skin preparation was associated with significantly reduced surgical site infection (SSI) in clean-contaminated surgery. Despite this, there is no evidence suggesting the use of chlorhexidine during hand scrub reduces SSI, which perhaps explains why guidelines from the World Health Organization, the Centers for Disease Control and Prevention and the Association for Perioperative Practice do not recommend one specific antimicrobial over another for hand scrub.

PDF

http://icvts.oxfordjournals.org/content/12/6/1017.full.pdf+html

August 27, 2012 at 8:21 am

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