Posts filed under ‘Infecciones parasitarias’

Shotgun Metagenomic Detection of Pathogens: a Micro-Comic Strip

Journal of Clinical Microbiology  August 2018 V.56 N.8

Editorial

Alexander J. McAdam

Next-generation sequencing has made shotgun metagenomic testing of primary clinical specimens for detection of pathogens feasible (1).

These technologies can routinely detect a range of pathogens (bacterial, viral, fungal, and eukaryotic parasites), allowing for hypothesis-free testing, in which test selection does not depend on knowing what pathogens are likely to be present.

Such testing has been applied for detecting infections or colonization of the nervous system (2–4), gastrointestinal tract (5, 6), prosthetic joints (7, 8), and blood or serum (9, 10).

Shotgun metagenomic testing for pathogens is now available for patient testing at a small number of academic and commercial laboratories, and it is expensive compared to other microbiology tests.

Where do the cost of and diversity of pathogens detected by shotgun metagenomic testing fit into the range of available microbiology tests?

FULL TEXT

http://jcm.asm.org/content/56/8/e00799-18?etoc

PDF

http://jcm.asm.org/content/56/8/e00799-18.full.pdf+html

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July 28, 2018 at 6:32 pm

Scabies outbreaks in ten care homes for elderly people: a prospective study of clinical features, epidemiology, and treatment outcomes

LANCET INFECTIOUS DISEASES August 2018 V.18 N.8 P.894–902

Background

Scabies outbreaks in residential and nursing care homes for elderly people are common, subject to diagnostic delay, and hard to control. We studied clinical features, epidemiology, and outcomes of outbreaks in the UK between 2014 and 2015.

Methods

We did a prospective observational study in residential care homes for elderly people in southeast England that reported scabies outbreaks to Public Health England health protection teams. An outbreak was defined as two or more cases of scabies (in either residents or staff) at a single care home. All patients who provided informed consent were included; patients with dementia were included if a personal or nominated consultee (ie, a family member or nominated staff member) endorsed participation. Dermatology-trained physicians examined residents at initial clinical visits, which were followed by two mass treatments with topical scabicide as per local health protection team guidance. Follow-up clinical visits were held 6 weeks after initial visits. Scabies was diagnosed through pre-defined case definitions as definite, probable, or possible with dermatoscopy and microscopy as appropriate.

Findings

230 residents were examined in ten outbreaks between Jan 23, 2014, and April 13, 2015. Median age was 86·9 years (IQR 81·5–92·3), 174 (76%) were female, and 157 (68%) had dementia. 61 (27%) residents were diagnosed with definite, probable, or possible scabies, of whom three had crusted scabies. Physical signs differed substantially from classic presentations. 31 (51%) of the 61 people diagnosed with scabies were asymptomatic, and only 25 (41%) had burrows. Mites were visualised with dermatoscopy in seven (11%) patients, and further confirmed by microscopy in three (5%). 35 (57%) cases had signs of scabies only on areas of the body that would normally be covered. Dementia was the only risk factor for a scabies diagnosis that we identified (odds ratio 2·37 [95% CI 1·38–4·07]). At clinical follow-up, 50 people who were initially diagnosed with scabies were examined. No new cases of scabies were detected, but infestation persisted in ten people.

Interpretation

Clinical presentation of scabies in elderly residents of care homes differs from classic descriptions familiar to clinicians. This difference probably contributes to delayed recognition and suboptimal management in this vulnerable group. Dermatoscopy and microscopy were of little value. Health-care workers should be aware of the different presentation of scabies in elderly people, and should do thorough examinations, particularly in people with dementia.

Funding

Public Health England and British Skin Foundation.

FULL TEXT

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(18)30347-5/fulltext?dgcid=raven_jbs_etoc_email

PDF

https://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(18)30347-5.pdf

July 26, 2018 at 12:40 pm

Diagnostic Performance of a Molecular Test versus Clinician Assessment of Vaginitis

Clin. Microbiol. June 2018 56:13 e00252-18

Jane R. Schwebke, Charlotte A. Gaydos, Paul Nyirjesy, Sonia Paradis, Salma Kodsi, and Charles K. Cooper

Vaginitis is a common complaint, diagnosed either empirically or using Amsel’s criteria and wet mount microscopy. This study sought to determine characteristics of an investigational test (a molecular test for vaginitis), compared to reference, for detection of bacterial vaginosis, Candida spp., and Trichomonas vaginalis. Vaginal specimens from a cross-sectional study were obtained from 1,740 women (≥18 years old), with vaginitis symptoms, during routine clinic visits (across 10 sites in the United States).

Specimens were analyzed using a commercial PCR/fluorogenic probe-based investigational test that detects bacterial vaginosis, Candida spp., and Trichomonas vaginalis. Clinician diagnosis and in-clinic testing (Amsel’s test, potassium hydroxide preparation, and wet mount) were also employed to detect the three vaginitis causes.

All testing methods were compared to the respective reference methods (Nugent Gram stain for bacterial vaginosis, detection of the Candida gene its2, and Trichomonas vaginalis culture). The investigational test, clinician diagnosis, and in-clinic testing were compared to reference methods for bacterial vaginosis, Candida spp., and Trichomonas vaginalis.

The investigational test resulted in significantly higher sensitivity and negative predictive value than clinician diagnosis or in-clinic testing. In addition, the investigational test showed a statistically higher overall percent agreement with each of the three reference methods than did clinician diagnosis or in-clinic testing.

The investigational test showed significantly higher sensitivity for detecting vaginitis, involving more than one cause, than did clinician diagnosis. Taken together, these results suggest that a molecular investigational test can facilitate accurate detection of vaginitis.

abstract

http://jcm.asm.org/content/56/6/e00252-18.abstract

PDF

http://jcm.asm.org/content/56/6/e00252-18.full.pdf+html

June 12, 2018 at 7:34 am

Is it safe to go back into the water? A systematic review and meta-analysis of the risk of acquiring infections from recreational exposure to seawater

International Journal of Epidemiology February 26, 2018

Anne F C Leonard  Andrew Singer  Obioha C Ukoumunne  William H Gaze  Ruth Garside

Abstract

Background

Numerous illnesses are associated with bathing in natural waters, although it is assumed that the risk of illness among bathers exposed to relatively clean waters found in high-income countries is negligible. A systematic review was carried out to quantify the increased risk of experiencing a range of adverse health outcomes among bathers exposed to coastal water compared with non-bathers.

Methods

In all 6919 potentially relevant titles and abstracts were screened, and from these 40 studies were eligible for inclusion in the review. Odds ratios (OR) were extracted from 19 of these reports and combined in random-effect meta-analyses for the following adverse health outcomes: incident cases of any illness, ear infections, gastrointestinal illness and infections caused by specific microorganisms.

Results

There is an increased risk of experiencing symptoms of any illness [OR = 1.86, 95% confidence interval (CI): 1.31 to 2.64, P = 0.001] and ear ailments (OR = 2.05, 95% CI: 1.49 to 2.82, P < 0.001) in bathers compared with non-bathers. There is also an increased risk of experiencing gastrointestinal ailments (OR = 1.29, 95% CI: 1.12 to 1.49, P < 0.001).

Conclusions

This is the first systematic review to evaluate evidence on the increased risk of acquiring illnesses from bathing in seawater compared with non-bathers. Our results support the notion that infections are acquired from bathing in coastal waters, and that bathers have a greater risk of experiencing a variety of illnesses compared with non-bathers.

FULL TEXT

https://academic.oup.com/ije/advance-article/doi/10.1093/ije/dyx281/4911079

PDF (CLIC en PDF) FREE

March 23, 2018 at 7:55 am

Treating malaria: new drugs for a new era

Lancet Infectious Diseases December 2017 V.17 N.12 P.1223–1224

COMMENT

Treating malaria: new drugs for a new era

G Dennis Shanks, Jörg J Möhrle

In The Lancet Infectious Diseases, Ousmane Koita and colleagues1 reported the results of a randomised, phase 2, non-inferiority clinical trial. They compared AQ-13, a next generation 4-aminoquinoline (4-AQ) compound, with artemether plus lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in 66 Malian men.

The per-protocol analysis of this well executed trial showed that both groups had similar proportions cured (28 [100%] of 28 for AQ-13 vs 31 [93·9%] of 33 for artemether plus lumefantrine; p=0·50) and non-inferiority of AQ-13 to artemether plus lumefantrine (difference −6·1%, 95% CI −14·7 to 2·4). The intention-to-treat analysis also showed that proportions cured were also similar between the groups (28 [84·8%] of 33 for AQ-13 vs 31 [93·9%] of 33 for artemether plus lumefantrine; p=0·43); however, this analysis did not show non-inferiority of AQ-13 to artemether plus lumefantrine (difference 9·1%, 95% CI −5·6 to 23·8). The study’s suboptimal number of participants was possibly due to civil military disturbances in Mali or improving malaria control in the Sahel. The data presented show AQ-13 to be efficacious in this relatively easy-to-treat population. The next challenge is to understand how well AQ-13 will treat patients who have lower or no immunity to malaria, such as African children….

FULL TEXT

http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30475-9/fulltext?elsca1=etoc

PDF

http://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(17)30475-9.pdf

 

 

Lancet Infectious Diseases December 2017 V.17 N.12 P.1266–1275

AQ-13, an investigational antimalarial, versus artemether plus lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria: a randomised, phase 2, non-inferiority clinical trial

Prof Ousmane A Koita, PhD, Lansana Sangaré, PhD, Haiyan D Miller, BS, Aliou Sissako, MD, Moctar Coulibaly, MD, Trevor A Thompson, BS, Prof Saharé Fongoro, MD, Youssouf Diarra, PharmD, Mamadou Ba, PhD, Prof Ababacar Maiga, PhD, Prof Boubakar Diallo, MD, David M Mushatt, MD, Frances J Mather, PhD, Jeffrey G Shaffer, PhD, Asif H Anwar, MD, Prof Donald J Krogstad

Background

Chloroquine was used for malaria treatment until resistant Plasmodium falciparum was identified. Because 4-aminoquinolines with modified side chains, such as AQ-13, are active against resistant parasites, we compared AQ-13 against artemether plus lumefantrine for treatment of uncomplicated P falciparum malaria.

Methods

We did a randomised, non-inferiority trial. We screened men (≥18 years) with uncomplicated malaria in Missira (northeast Mali) and Bamako (capital of Mali) for eligibility (≥2000 asexual P falciparum parasites per μL of blood). Eligible participants were randomly assigned to either the artemether plus lumefantrine group or AQ-13 group by permuting blocks of four with a random number generator. Physicians and others caring for the participants were masked, except for participants who received treatment and the research pharmacist who implemented the randomisation and provided treatment. Participants received either 80 mg of oral artemether and 480 mg of oral lumefantrine twice daily for 3 days or 638·50 mg of AQ-13 base (two oral capsules) on days 1 and 2, and 319·25 mg base (one oral capsule) on day 3. Participants were monitored for parasite clearance (50 μL blood samples twice daily at 12 h intervals until two consecutive negative samples were obtained) and interviewed for adverse events (once every day) as inpatients during week 1. During the 5-week outpatient follow-up, participants were examined for adverse events and recurrent infection twice per week. All participants were included in the intention-to-treat analysis and per-protocol analysis, except for those who dropped out in the per-protocol analysis. The composite primary outcome was clearance of asexual parasites and fever by day 7, and absence of recrudescent infection by parasites with the same molecular markers from days 8 to 42 (defined as cure). Non-inferiority was considered established if the proportion of patients who were cured was higher for artemether plus lumefantrine than for AQ-13 and the upper limit of the 95% CI was less than the non-inferiority margin of 15%. This trial is registered at ClinicalTrials.gov, number NCT01614964.

Findings

Between Aug 6 and Nov 18, 2013, and between Sept 18 and Nov 20, 2015, 66 Malian men with uncomplicated malaria were enrolled. 33 participants were randomly assigned to each group. There were no serious adverse events (grade 2–4) and asexual parasites were cleared by day 7 in both groups. 453 less-severe adverse events (≤grade 1) were reported: 214 in the combination group and 239 in the AQ-13 group. Two participants withdrew from the AQ-13 group after parasite clearance and three were lost to follow-up. In the artemether plus lumefantrine group, two participants had late treatment failures (same markers as original isolates). On the basis of the per-protocol analysis, the AQ-13 and artemether plus lumefantrine groups had similar proportions cured (28 [100%] of 28 vs 31 [93·9%] of 33; p=0·50) and AQ-13 was not inferior to artemether plus lumefantrine (difference −6·1%, 95% CI −14·7 to 2·4). Proportions cured were also similar between the groups in the intention-to-treat analysis (28 of 33, 84·8% for AQ-13 vs 31 of 33, 93·9% for artemether and lumefantrine; p=0·43) but the upper bound of the 95% CI exceeded the 15% non-inferiority margin (difference 9·1%, 95% CI −5·6 to 23·8).

Interpretation

The per-protocol analysis suggested non-inferiority of AQ-13 to artemether plus lumefantrine. By contrast, the intention-to-treat analysis, which included two participants who withdrew and three who were lost to follow-up from the AQ-13 group, did not meet the criterion for non-inferiority of AQ-13, although there were no AQ-13 treatment failures. Studies with more participants (and non-immune participants) are needed to decide whether widespread use of modified 4-aminoquinolones should be recommended.

Funding

US Food and Drug Administration Orphan Product Development, National Institutes of Health, US Centers for Disease Control and Prevention, Burroughs-Wellcome Fund, US State Department, and WHO.

FULL TEXT

http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30365-1/fulltext?elsca1=etoc

PDF

http://www.thelancet.com/pdfs/journals/laninf/PIIS1473-3099(17)30365-1.pdf

 

November 24, 2017 at 8:35 am

A Rose by Any Other Name: Practical Updates on Microbial Nomenclature for Clinical Microbiology

Journal of Clinical Microbiology January 2017 V.55 N.1 P.3-4

EDITORIAL

Colleen S. Kraft, Alexander J. McAdam, and Karen C. Carroll

aDepartment of Pathology and Laboratory Medicine, Division of Infectious Disease, Emory University, Atlanta, Georgia, USA

bDepartment of Laboratory Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA

cDivision of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

The clinical microbiology laboratory stands at the interface between basic science, including the study of phylogeny, and applications of science in the very practical world of medical care.

In this context, it is important that laboratory reports balance scientific accuracy with medical utility, and it is particularly difficult to do this in the naming of microorganisms.

New organisms are discovered and named, and our understanding of the relationships between known organisms improves, resulting in the reclassification and renaming of organisms as they are sorted into the correct groups.

In this issue of Journal of Clinical Microbiology, we are pleased to provide several minireviews that are intended to help clinical microbiologists keep up-to-date with changes in nomenclature for bacteria (1), parasites (2), viruses (3), and fungi (4).

Most of these minireviews focus on human pathogens, but the minireview on viruses includes those affecting nonhuman animals. An article about mycobacterial nomenclature is in preparation and will be published in Journal of Clinical Microbiology when available.

The idea for this informative resource was proposed by Dr. Karen Carroll at the editors’ meeting in 2015.

The editors enthusiastically agreed these reviews would be a useful resource for clinical microbiologists, infectious diseases physicians, laboratory technologists, pharmacists, and infection preventionists, in addition to fostering discussion and teaching of trainees and students.

Several editors volunteered to write the articles, and we plan to update these minireviews every 2 years if they prove to be as useful as we expect….

PDF

http://jcm.asm.org/content/55/1/3.full.pdf+html

October 19, 2017 at 3:02 pm

False-Positive Rapid Malaria Antigen Test Result in a Returned Traveler

Journal of Clinical Microbiology August 2017 V.55 N.8 P.2294-2297

The Brief Case

Kristle L. Haberichter, Paul C. Johnson, Paul J. Chittick, Peter Millward, Barbara Robinson-Dunn, and Bobby L. Boyanton Jr.

A previously healthy 43-year-old female presented to her primary care physician with a 13-day history of recurrent nightly fevers (100°F to 101°F), nonproductive cough, and respiratory congestion. She was prescribed azithromycin, albuterol, and benzonatate. She presented to the emergency center 2 days later without improvement and at that time reported night sweats. She had recently traveled to Thailand, Laos, Cambodia, and the United Arab Emirates. The nightly fevers began 11 days after returning home. She acknowledged being bitten by mosquitoes throughout her travels and did not take malaria prophylaxis.

A previously healthy 43-year-old female presented to her primary care physician with a 13-day history of recurrent nightly fevers (100°F to 101°F), nonproductive cough, and respiratory congestion. She was prescribed azithromycin, albuterol, and benzonatate. She presented to the emergency center 2 days later without improvement and at that time reported night sweats. She had recently traveled to Thailand, Laos, Cambodia, and the United Arab Emirates. The nightly fevers began 11 days after returning home. She acknowledged being bitten by mosquitoes throughout her travels and did not take malaria prophylaxis….

PDF

http://jcm.asm.org/content/55/8/2294.full.pdf+html

 

 

Journal of Clinical Microbiology August 2017 V.55 N.8 P.2560-2561

Closing the Brief Case: False-Positive Rapid Malaria Antigen Test Result in a Returned Traveler

Kristle L. Haberichter, Paul C. Johnson, Paul J. Chittick, Peter Millward, Barbara Robinson-Dunn, and Bobby L. Boyanton Jr.

aDepartment of Pathology and Laboratory Medicine, Beaumont Health, Royal Oak, Michigan, USA

bDepartment of Infectious Disease, Beaumont Health, Royal Oak, Michigan, USA

cOakland University William Beaumont School of Medicine, Rochester, Michigan, USA

ANSWERS TO SELF-ASSESSMENT QUESTIONS

PDF

http://jcm.asm.org/content/55/8/2560.full.pdf+html

July 26, 2017 at 9:23 am

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