Archive for September 19, 2011

Comparison of three rapid and easy bacterial DNA extraction methods for use with quantitative real-time PCR

European J of Clin Microbiol & Infect Dis. Aug 2011 V.30 N.9 P.1053-1061

S. P. van Tongeren, J. E. Degener and H. J. M. Harmsen

Abstract

The development of fast and easy on-site molecular detection and quantification methods for hazardous microbes on solid surfaces is desirable for several applications where specialised laboratory facilities are absent. The quantification of bacterial contamination necessitates the assessment of the efficiency of the used methodology as a whole, including the preceding steps of sampling and sample processing. We used quantitative real-time polymerase chain reaction (qrtPCR) for Escherichia coli and Staphylococcus aureus to measure the recovery of DNA from defined numbers of bacterial cells that were subjected to three different DNA extraction methods: the QIAamp® DNA Mini Kit, Reischl et al.’s method and FTA® Elute. FTA® Elute significantly showed the highest median DNA extraction efficiency of 76.9% for E. coli and 108.9% for S. aureus. The Reischl et al. method and QIAamp® DNA Mini Kit inhibited the E. coli qrtPCR assay with a 10-fold decrease of detectable DNA. None of the methods inhibited the S. aureus qrtPCR assay. The FTA® Elute applicability was demonstrated with swab samples taken from the International Space Station (ISS) interior. Overall, the FTA® Elute method was found to be the most suitable to selected criteria in terms of rapidity, easiness of use, DNA extraction efficiency, toxicity, and transport and storage conditions.

abstract

http://www.springerlink.com/content/h4683v26378n8205/

PDF

http://www.springerlink.com/content/h4683v26378n8205/fulltext.pdf

September 19, 2011 at 5:31 pm Leave a comment

Evaluation of a commercial multiplex PCR test (SeptiFast) in the etiological diagnosis of community-onset bloodstream infections

European J of Clin Microbiol & Infect Dis. Aug 2011 V.30 N.9 P.1127-1134

P. Josefson, K. Strålin, A. Ohlin, T. Ennefors, B. Dragsten, L. Andersson, H. Fredlund, P. Mölling and P. Olcén

Abstract

The commercial polymerase chain reaction (PCR) test, SeptiFast, is designed to identify the DNA of individual bacterial and fungal pathogens in whole blood. We aimed to evaluate the usefulness of the test for the detection of community-onset bloodstream infections. We prospectively included adult patients who were subjected to blood culture (BC) at an infectious diseases department. For the evaluation, one BC/PCR set (two BC bottles and one PCR tube) per patient was used. When several sets were obtained and analyzed, the first set with any positive result was evaluated. Among 1,093 consecutively included patients, BC was positive in 138 and PCR was positive in 107. Fifty positive PCR results were supported by BC in the same BC/PCR set, ten were supported by other cultures, and, additionally, ten were supported by the clinical presentation. Compared with BC, PCR showed specificities and negative predictive values of >97% for all detectable pathogens. The following sensitivities and positive predictive values (PPVs) were noted: Staphylococcus aureus, 67% and 43%; Streptococcus pneumoniae, 12% and 67%; other Streptococcus species, 43% and 77%; Escherichia coli, 53% and 56%; and Klebsiella species, 43% and 23%. If support from other cultures and the clinical presentation were included in the reference standard, the PPVs for the detection of these bacteria were 57%, 100%, 92%, 75%, and 69%, respectively. Although the specificities were high, the low sensitivities and suboptimal PPVs noted in the present study discourage routine use of the test in its present form for the detection of community-onset bloodstream infections.

abstract

http://www.springerlink.com/content/73430jru27q740l7/

September 19, 2011 at 5:30 pm Leave a comment

Update in treatment of Chagas disease

Current Opinion in Infectious Diseases Oct 2011 V.24 N.5 P.428-434

Le Loup, Guillaumea,b,c; Pialoux, Gillesa; Lescure, François Xaviera

Abstract

Purpose of review

This review discusses the recent data about the pathogenesis of Chagas disease, tolerance of drugs, and follow-up of patients impacting the treatment of Chagas disease in immunocompetent and immunocompromised patients.

Recent findings

The role of the parasite to promote direct or indirect organ damage in the chronic phase of the disease as well as the usefulness of antiparasitic treatment to slow or prevent the deterioration of cardiac function and the aggravation of Chagasic cardiomyopathy lead to an extension of the indications of treatment. Tolerance is poor for the two drugs, benznidazole and nifurtimox. The rates of adverse events and treatment discontinuation before 60 days are higher with nifurtimox. PCR, and in the near future immunologic tests, might allow assessment of the early success or failure of the antiparasitic treatment.

Summary

Assessment of alternative drugs, such as posaconazole, and of new strategies of treatment (combination of two antiparasitic drugs, association of antiparasitic and immunomodulatory drugs, and re-treatment), and follow-up are a global health priority.

abstract

http://journals.lww.com/co-infectiousdiseases/Abstract/2011/10000/Update_in_treatment_of_Chagas_disease.6.aspx

September 19, 2011 at 3:50 pm Leave a comment

The role of antimalarial treatment in the elimination of malaria

Clinical Microbiology and Infection Aug 2011

Roly D Gosling1,2, Lucy Okell3, Jacklin Mosha4, Daniel Chandramohan2

Abstract

With declining transmission in malaria in several regions of the world and renewed interest in the elimination of malaria, strategies for malaria control using antimalarial drugs are being revisited. Drug based strategies to reduce transmission of malaria need to target the asymptomatic carriers of infection. Drugs that are effective against gametocytes are few, but it may be possible to reduce gametocyte production by killing the asexual stages, for which more drugs are available. Drugs for use in large scale programs must be safe and tolerable. Strategies include improving access to treatment for malaria with an efficacious drug, intermittent treatment programs, and mass drug administration, with and without screening for malaria. Recent proposals target high risk groups for interventions. None of the strategies have been rigorously tested with appropriate control groups for comparison. With the lack of field evidence, modeling has been used. Models have shown firstly that for long lasting effects, drug administration programs should be linked with vector control and secondly, that if elimination is the aim, programs are likely to be more successful when applied to smaller populations of a few thousand or less. In order to sustain the gains following the scaling up of vector control and use of ACTs, strategies that use antimalarials effectively need to be devised and evidence generated for the most cost efficient way forward.

abstract

http://onlinelibrary.wiley.com/doi/10.1111/j.1469-0691.2011.03660.x/abstract

– – –

Clinical Microbiology and Infection Aug 2011

Malaria parasites: Elimination is not eradication

V. Robert1, J.-F. Trape2, C. Rogier3

Summary

The fight against malaria is currently achieving patent successes. There is a growing body of evidence that full elimination of malaria parasites is possible. The goals of zero transmission and no autochthonous cases are thus realistic in the short term in many countries. This unprecedented situation has cast new light on two of the most discussed concept in Malariology — elimination and eradication. In this editorial, we introduce the theme issue of Clinical Microbiology and Infection devoted to malaria elimination; we describe the current malaria situation worldwide and identify remaining barriers to elimination.

abstract

http://onlinelibrary.wiley.com/doi/10.1111/j.1469-0691.2011.03657.x/abstract

– – –

 

September 19, 2011 at 3:48 pm Leave a comment

HIV Vaccine Development — Improving on Natural Immunity

N Engl J of Medicine Sept 8, 2011 V.365  P.873-875

PERPECTIVE

Margaret I. Johnston, Ph.D., and Anthony S. Fauci, M.D.

Although a number of methods of preventing infection with the human immunodeficiency virus (HIV) have proven effective to varying degrees, it is generally agreed that a safe and effective vaccine against HIV infection would be a critical component of a highly effective prevention toolkit for controlling and ultimately ending the global AIDS pandemic. For nearly all important pathogens for which effective vaccines have been developed, such as smallpox, measles, and poliovirus, there exists a natural model of protection: the immune response to the pathogen ultimately clears the microbe from the body and confers durable protection against reinfection. Under these circumstances, the human immune system has already provided us with proof of the concept that it can generate a protective response. This fact has led to a fundamental tenet of vaccinology: the best way to develop an effective vaccine is to design a candidate that mimics infection and induces responses akin to natural immunity.

abstract

http://www.nejm.org/doi/full/10.1056/NEJMp1107621?query=TOC

PDF

http://www.nejm.org/doi/pdf/10.1056/NEJMp1107621

September 19, 2011 at 12:21 am Leave a comment

Environmental Risk Factors for Pulmonary Mycobacterium avium-intracellulare Complex Disease

Chest  September 2011 V.140 N.3 P.723-729

Koichi Maekawa, MD, Yutaka Ito, MD, PhD, Toyohiro Hirai, MD, PhD, Takeshi Kubo, MD, PhD, Seiichiro Imai, MD, Shuji Tatsumi, MD, Kohei Fujita, MD, Shunji Takakura, MD, PhD, Akio Niimi, MD, PhD, Yoshitsugu Iinuma, MD, PhD, Satoshi Ichiyama, MD, PhD, Kaori Togashi, MD, PhD and Michiaki Mishima, MD, PhD

From the Department of Respiratory Medicine (Drs Maekawa, Ito, Hirai, Imai, Tatsumi, Fujita, Niimi, and Mishima), the Department of Nuclear Medicine and Diagnostic Imaging (Drs Kubo and Togashi), and the Department of Clinical Laboratory Medicine (Drs Takakura and Ichiyama), Graduate School of Medicine, Kyoto University, Kyoto; and the Department of Infectious Diseases (Dr Iinuma), Kanazawa Medical University, Kanazawa, Japan.

Abstract

Background

Mycobacterium avium-intracellulare complex (MAC) is a ubiquitous pathogen found in soil and water. Environmental exposure is the primary route for MAC infection. However, specific environmental risk factors have been poorly determined in immunocompetent patients with pulmonary MAC disease.

Methods

A case-control study was performed with 106 patients with pulmonary MAC disease (men [women], 23 [83]; age, 64.3 ± 9.2 years) and 53 age-matched control patients with bronchiectasis but not pulmonary MAC infection (men [women], 7[46]; age, 63.0 ± 11.0 years). All participants completed a standardized questionnaire that included questions about medical history, smoking history, alcohol usage, age at menopause, and environment exposures. Environment exposures included soil exposure from farming or gardening; water exposure from bathing, showering, hot tub use, dishwashing, swimming, and drinking water; and pet exposure.

Results

No differences were identified in the patient characteristics and underlying diseases. More case patients experienced high soil exposure (≥ 2 per week) than control patients (23.6% vs 9.4%, P = .032); this remained significant after multivariate analysis (OR, 5.9; 95% CI, 1.4-24.7; P = .015). There were no significant differences in other environmental exposures. Case patients with high soil exposure were significantly older than those with low soil exposure (67.3 ± 7.3 years vs 64.3 ± 9.5 years, P = .037). Other characteristics, underlying diseases, and mycobacterial species did not differ between the two groups.

Conclusions

Patients with pulmonary MAC disease had significantly more soil exposure than noninfected control patients, which suggests that environmental soil exposure is a likely risk factor for the development of pulmonary MAC disease.

abstract

http://chestjournal.chestpubs.org/content/140/3/723.abstract?etoc

September 19, 2011 at 12:19 am Leave a comment

Acute Hepatitis as a Manifestation of Parvovirus B19 Infection

Journal of Clinical Microbiology 1 September 2011  V.49 N.9 P.3422-3424

CASE REPORTS

Aleisha Hatakka1, Julianne Klein2, Runtao He3, Jessica Piper3, Edward Tam4 and Andrew Walkty1,5,6*

Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada,1

Department of Pathology, Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada,2

National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada,3

The Liver and Intestinal Research Centre, Vancouver, British Columbia, Canada,4

Department of Clinical Microbiology, Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada,5

Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada6

There are few reports in the literature of hepatitis as a manifestation of parvovirus B19 infection. We describe a case of parvovirus B19-associated acute hepatitis diagnosed based on a positive serologic test (IgM) and molecular detection of parvovirus B19 DNA in a liver biopsy specimen. Parvovirus B19 infection should be considered in the differential diagnosis of patients presenting with acute hepatitis.

abstract

http://jcm.asm.org/cgi/content/abstract/49/9/3422

September 19, 2011 at 12:15 am Leave a comment


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