Positive qPCR Research Articles

Exploring the parasite load and molecular diversity of Trypanosoma cruzi in patients with chronic Chagas disease from different regions of Brazil.

Chagas disease is still a major public health issue in many Latin American countries. One of the current major challenges is to find an association between Trypanosoma cruzi discrete typing units (DTUs) and clinical manifestations of the disease. In this study, we used a multilocus conventional PCR and quantitative real time PCR (qPCR) approaches to perform the molecular typing and parasite load quantification directly from blood specimens of 65 chronic Chagas disease patients. All patients were recruited at the same health center, but their place of birth were widely distributed in different geographic regions of Brazil. Of the 65 patients, 35 (53.8%) presented positive amplification by real time qPCR, being 20 (30.7%) with the clinical indeterminate form and 15 (23.1%) with the cardiac form of the disease. The parasite load median for all positive patients was 2.54 [1.43–11.14] parasite equivalents/mL (par. Eq./mL), with the load ranging from 0.12 to 153.66 par. Eq./mL. Noteworthy, the parasite load was significantly higher in patients over 70 years old (median 20.05 [18.29–86.86] par. Eq./mL). Using guanidine-EDTA blood samples spiked with reference T. cruzi strains, belonging to the six DTUs, it was possible to genotype the parasite up to 0.5 par. Eq./mL, with high specificity. Of the patients with positive qPCR, it was possible to identify the T. cruzi DTU in 28 patients (80%). For the remaining patients (20%), at least a partial result was obtained. Analysis of specimens showed prevalences of TcVI, TcII and mixed infection TcVI+TcII equal to 40%, 17.1% and 14.3%, respectively. In addition, two patients were infected by TcV, and one patient was coinfected by TcIII+TcVI, These last three patients were in stage A of chronic chagasic cardiomyopathy (CCC), and they were born at the Bahia State (northeast region of Brazil). When T. cruzi genotypes were compared with the parasite load, more elevated parasite loads were observed in patients infected by TcII in general (parasite load median of 7.56 par. Eq./mL) in comparison to patients infected by TcVI (median of 2.35 par. Eq./mL). However, while the frequency of CCC was 50% in patients infected by TcVI and TcV, only 16.7% of patients infected by TcII evolved to CCC. Taking together, our results contribute to update the epidemiological knowledge of T. cruzi DTUs in Brazil, and highlight the age of patient and infection by TcII as important features that lead to the observation of higher parasitemia levels.

A case report of scrub typhus complicated with myocarditis and rhabdomyolysis

BackgroundScrub typhus is a zoonotic disease caused by Orientia tsutsugamushi, a gram-negative intracellular bacterium. Myocarditis and rhabdomyolysis are rare complications of scrub typhus.Case presentationWe report a case of scrub typhus, which was simultaneously complicated with myocarditis and rhabdomyolysis. A 54-year-old woman presented to our hospital with myalgia in the upper and lower limbs, oedema and a fever of 7 days’ duration. We confirmed the diagnosis of scrub typhus complicated with myocarditis by pericardial fluid analysis and cardiac magnetic resonance imaging results. The pericardial fluid showed characteristics of an exudate, an elevated immunofluorescence assay (IFA) IgG titer of 1:2048 and a positive 16S rRNA qPCR result. We also diagnosed rhabdomyolysis by the patient’s presenting symptoms, elevated muscle enzyme levels and bone scan results.ConclusionWe report for the first time a case of scrub typhus complicated with both myocarditis and rhabdomyolysis, the causative agent of which was the Boryong genotype of O. tsutsugamushi.

General overview of the detection of Mycoplasma hyopneumoniae DNA by quantitative polymerase chain reaction in diagnostic cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2004 to 2016

Mycoplasma hyopneumoniae (Mhp) is the etiologic agent of enzootic pneumonia and a major causative agent of the porcine respiratory disease complex. This study summarizes and describes the general diagnostic trends on Mhp detection by quantitative polymerase chain reaction (qPCR) in cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2004 to 2016. The following variables were included in the analysis: animal age, geographic location, sample type, season, and submission year. The overall frequency of detection found was 27.04% and ranged from 17.9% to 40.7%. Lung homogenate and bronchial swabs had a greater Mhp qPCR detection rate than other sample types (P < .001) followed by bronchoalveolar lavage (P < .001), while oral fluids had the lowest Mhp detection rate (P < .001). The fall season had a greater percentage of positive Mhp qPCR results when compared to other seasons (P < .001), while spring had the lowest percentage. Finishing-age pigs had a greater percentage of Mhp qPCR detection when compared to other age groups (P < .001), while suckling pigs had the lowest percentage (P < .001).

Prospective study of canine leptospirosis in shelter and stray dog populations: Identification of chronic carriers and different Leptospira species infecting dogs

Dogs are highly susceptible to the leptospiral infection, notably stray and sheltered dogs. Unsanitary conditions often observed in dog shelters may predispose the introduction and spread of leptospires among sheltered populations, potentially increasing the chances for the inadvertent adoption of asymptomatically infected animals. The present work describes a longitudinal study using a multidisciplinary approach for the identification of chronically infected dogs and the characterization of potentially pathogenic strains circulating among stray and sheltered dog populations in São Paulo, Brazil. A total of 123 dogs from three populations were included. The initial evaluation consisted of blood and urine quantitative PCR testing (qPCR), the detection of specific antibodies by microscopic agglutination test (MAT), physical examination and hematological and serum biochemistry analyses. The qPCR-positive dogs were prospectively examined, and reevaluations also included culture from urine samples. Positive qPCR samples were subjected to 16S rRNA and secY gene phylogenetic analysis. The recovered strains were characterized by Multilocus Sequence Typing, polyclonal serogroup identification and virulence determination. Leptospiruria was detected in all populations studied (13/123), and phylogenetic analysis revealed that 10 dogs had L. interrogans infection. Three dogs (3/13) had L. santarosai infection. The secY phylogenetic analysis revealed that the L. santarosai sequences clustered separately from those obtained from other hosts. Ten leptospiruric dogs were reevaluated, and three dogs presented persistent leptospiruria, allowing culturing from two dogs. The strains were characterized as L. interrogans serogroup Canicola (virulent) and L. santarosai serogroup Sejroe (not virulent). Serum samples were retested by MAT using the DU92 and DU114 strains as antigens, and no increased seroreactivity was detected. Asymptomatic L. santarosai infection was observed in all populations studied, suggesting a possible role of dogs in the chain of transmission of this leptospiral species. The results suggest a genetic distinction between lineages of Brazilian L. santarosai maintained by dogs and other animal hosts. Our findings revealed that dogs could act as maintenance hosts for distinct pathogenic Leptospira, highlighting also that asymptomatically infected dogs can be inadvertently admitted and adopted in dog shelters, potentially increasing the risks of zoonotic transmission.

Needle in a haystack? A comparison of eDNA metabarcoding and targeted qPCR for detection of the great crested newt (Triturus cristatus).

Environmental DNA (eDNA) analysis is a rapid, cost‐effective, non‐invasive biodiversity monitoring tool which utilises DNA left behind in the environment by organisms for species detection. The method is used as a species‐specific survey tool for rare or invasive species across a broad range of ecosystems. Recently, eDNA and “metabarcoding” have been combined to describe whole communities rather than focusing on single target species. However, whether metabarcoding is as sensitive as targeted approaches for rare species detection remains to be evaluated. The great crested newt Triturus cristatus is a flagship pond species of international conservation concern and the first UK species to be routinely monitored using eDNA. We evaluate whether eDNA metabarcoding has comparable sensitivity to targeted real‐time quantitative PCR (qPCR) for T. cristatus detection. Extracted eDNA samples (N = 532) were screened for T. cristatus by qPCR and analysed for all vertebrate species using high‐throughput sequencing technology. With qPCR and a detection threshold of 1 of 12 positive qPCR replicates, newts were detected in 50% of ponds. Detection decreased to 32% when the threshold was increased to 4 of 12 positive qPCR replicates. With metabarcoding, newts were detected in 34% of ponds without a detection threshold, and in 28% of ponds when a threshold (0.028%) was applied. Therefore, qPCR provided greater detection than metabarcoding but metabarcoding detection with no threshold was equivalent to qPCR with a stringent detection threshold. The proportion of T. cristatus sequences in each sample was positively associated with the number of positive qPCR replicates (qPCR score) suggesting eDNA metabarcoding may be indicative of eDNA concentration. eDNA metabarcoding holds enormous potential for holistic biodiversity assessment and routine freshwater monitoring. We advocate this community approach to freshwater monitoring to guide management and conservation, whereby entire communities can be initially surveyed to best inform use of funding and time for species‐specific surveys.

Molecular, immunological and neurophysiological evaluations for early diagnosis of neural impairment in seropositive leprosy household contacts.

BackgroundHousehold contacts constitute the highest risk group for leprosy development, and despite significant progress in the disease control, early diagnosis remains the primary goals for leprosy management programs.MethodsWe have recruited 175 seropositive and 35 seronegative household contacts from 2014 to 2016, who were subjected to an extensive protocol that included clinical, molecular (peripheral blood qPCR, slit-skin smear qPCR, skin biopsy qPCR) and electroneuromyographic evaluations.Results/Principal findingsThe positivity of peripheral blood qPCR of seropositive contacts was 40.6% (71/175) whereas only 8.6% (3/35) were qPCR positive in seronegative contacts (p = 0.0003). For the slit-skin smear, only 4% (7/175) of seropositive contacts presented positive bacilloscopy, whereas the qPCR detected 47.4% (83/175) positivity in this group compared with only 17.1% (6/35) in seronegative contacts (p = 0.0009). In the ENMG evaluation of contacts, 31.4% (55/175) of seropositives presented some neural impairment, and 13.3% (4/35) in seronegatives (p = 0.0163). The presence of neural thickening conferred a 2.94-fold higher chance of ENMG abnormality (p = 0.0031). Seropositive contacts presented a 4.04-fold higher chance of neural impairment (p = 0.0206). The peripheral blood qPCR positivity presented odds 2.08-fold higher towards neural impairment (OR, 2.08; p = 0.028). Contrarily, the presence of at least one BCG vaccine scar demonstrated 2.44-fold greater protection against neural impairment (OR = 0.41; p = 0.044).Conclusions/SignificanceELISA anti-PGL-I is the most important test in determining the increased chance of neural impairment in asymptomatic leprosy household contacts. The combination of the two assays (ELISA anti-PGL-I and peripheral blood qPCR) and the presence of BCG scar may identify individuals with higher chances of developing leprosy neuropathy, corroborating with the early diagnosis and treatment.

Pneumocystosis and quantitative PCR

ObjectivePneumocystis pneumonia (PCP) is now predominantly observed in immunosuppressed non-HIV-infected patients. The sensitivity of the PCR is here higher than direct examination (DE) of respiratory secretions because the infection is caused by a lower inoculum of Pneumocystis jirovecii (P. jirovecii). The objective of our retrospective study was to assess the contribution of quantitative PCR (qPCR) in the diagnosis of PCP. Patients and methodsAll patients hospitalized for PCP suspicion with a positive qPCR were included. Irrespective of the qPCR value, patients were initially classified into two groups (infection and colonization [PCP ruled out]) based on clinical, radiological, and microbiological data. Both groups were then compared based on the qPCR value. ResultsBetween 2013 and 2016, 150 patients were included; 75% of them were not infected with HIV. The diagnosis of PCP was retained for 129 patients and rejected for 21 patients. The DE was negative in 60% of PCP cases. The median value of qPCR was 76,650copies/mL among infected patients and 3220copies/mL among colonized patients. The threshold corresponding to a specificity of 100% was 56,000copies/mL. The optimal value to distinguish an infection from a colonization was 10,100copies/mL. ConclusionOur study confirms the diagnostic value of the qPCR in immunosuppressed patients, especially when the DE is negative. When the qPCR is˂56,000copies/mL, the result should be interpreted based on the clinical context and paraclinical examinations.

Association between canine leishmaniosis and Ehrlichia canis co-infection: a prospective case-control study

BackgroundIn the Mediterranean basin, Leishmania infantum is a major cause of disease in dogs, which are frequently co-infected with other vector-borne pathogens (VBP). However, the associations between dogs with clinical leishmaniosis (ClinL) and VBP co-infections have not been studied. We assessed the risk of VBP infections in dogs with ClinL and healthy controls.MethodsWe conducted a prospective case-control study of dogs with ClinL (positive qPCR and ELISA antibody for L. infantum on peripheral blood) and clinically healthy, ideally breed-, sex- and age-matched, control dogs (negative qPCR and ELISA antibody for L. infantum on peripheral blood) from Paphos, Cyprus. We obtained demographic data and all dogs underwent PCR on EDTA-blood extracted DNA for haemoplasma species, Ehrlichia/Anaplasma spp., Babesia spp., and Hepatozoon spp., with DNA sequencing to identify infecting species. We used logistic regression analysis and structural equation modelling (SEM) to evaluate the risk of VBP infections between ClinL cases and controls.ResultsFrom the 50 enrolled dogs with ClinL, DNA was detected in 24 (48%) for Hepatozoon spp., 14 (28%) for Mycoplasma haemocanis, 6 (12%) for Ehrlichia canis and 2 (4%) for Anaplasma platys. In the 92 enrolled control dogs, DNA was detected in 41 (45%) for Hepatozoon spp., 18 (20%) for M. haemocanis, 1 (1%) for E. canis and 3 (3%) for A. platys. No Babesia spp. or “Candidatus Mycoplasma haematoparvum” DNA was detected in any dog. No statistical differences were found between the ClinL and controls regarding age, sex, breed, lifestyle and use of ectoparasitic prevention. A significant association between ClinL and E. canis infection (OR = 12.4, 95% CI: 1.5–106.0, P = 0.022) was found compared to controls by multivariate logistic regression. This association was confirmed using SEM, which further identified that younger dogs were more likely to be infected with each of Hepatozoon spp. and M. haemocanis, and dogs with Hepatozoon spp. were more likely to be co-infected with M. haemocanis.ConclusionsDogs with ClinL are at a higher risk of co-infection with E. canis than clinically healthy dogs. We recommend that dogs diagnosed with ClinL should be tested for E. canis co-infection using PCR.

Dynamics of Afebrile Plasmodium falciparum Infections in Mozambican Men.

Afebrile Plasmodium falciparum infections usually remain undetected and untreated in the community and could potentially contribute to sustaining local malaria transmission in areas aiming for malaria elimination. Thirty-two men with afebrile P. falciparum infections detected with rapid diagnostic test (RDTs) were followed for 28 days. Kaplan-Meier estimates were computed to estimate probability of parasite positivity and of reducing parasitemia by half of its initial level by day 28. Trends of parasite densities quantified by microscopy and real-time quantitative polymerase chain reaction (qPCR) were assessed using Poisson regression models, and the microscopy-to-qPCR positivity ratio was calculated at each time point. Three survival distributions (Gompertz, Weibull, and gamma) were used to evaluate their strength of fit to the data and to predict the median lifetime of infection. The cumulative probability of parasite qPCR positivity by day 28 was 81% (95% confidence interval [CI], 60.2-91.6). Geometric mean parasitemia at recruitment was 516.1 parasites/μL and fell to <100 parasites/μL by day 3, reaching 56.7 parasites/μL on day 28 (P < .001). The ratio of P. falciparum-positive samples by microscopy to qPCR decreased from 0.9 to 0.52 from recruitment to day 28. The best model fit to the data was obtained assuming a Gompertz distribution. Afebrile P. falciparum infections detectable by RDT in semi-immune adults fall and stabilize at low-density levels during the first 4 days after detection, suggesting a rapid decline of potential transmissibility in this hidden parasite reservoir. NCT02698748.

Q fever epidemic in Cayenne, French Guiana, epidemiologically linked to three-toed sloth.

A Q fever epidemic occurred in 2013 in a small military residential area in Cayenne, French Guiana. A retrospective cohort study was conducted to identify Q fever risk factors. Confirmed acute Q fever case was defined as positive serology (IgM ≥ 50 and phase II IgG ≥ 200) and/or positive qPCR on serum or blood. In addition, wild mammals were captured at the study site and tested by serology and real-time PCR performed on blood, vaginal swabs and ticks. The attack rate was 20 percent (11/54). All the cases were symptomatic with fever >38.5 °C and community-acquired pneumonia for four cases. Log binomial multivariate models identified two independent risk factors associated with Q fever: to clean the house (RRa = 7.5 CI95% [1.03-55.3]) and to carry a three-toed sloth in arms (RRa = 2.6 CI95% [1.1-5.8]). Eighteen marsupial individuals were captured, all PCRs were negative but 17% (3/18) had a positive serology. Another study conducted after the epidemic found only one (1/4) three-tooth sloth (Bradypus tridactylus) with feces highly infectious for C. burnetii MST17. The same strain C. burnetii genotype 17 has been laboratory- confirmed in this mammal and in human cases. These results support the implication of three-toed-sloth in this epidemic. Human contamination mainly occurs through inhalation of infectious aerosols as suggested by high relative risk associated with house cleaning activities and pulmonary forms of the disease, and through direct contact with three- toed-sloth. Positive serological results among marsupials confirm wildlife exposure and suggest a more complex sylvatic transmission cycle among wild mammals.

LytA Quantitative PCR on Sputum and Nasopharyngeal Swab Samples for Detection of Pneumococcal Pneumonia among the Elderly.

ABSTRACTReal-time quantitative PCR (qPCR) assay of sputum or nasopharyngeal specimens has shown promising results in the detection of pneumococcal community-acquired pneumonia (PncCAP). We applied qPCR for the autolysin gene (lytA) and compared sputum and nasopharyngeal swab (NPS) pneumococcal loads in elderly patients with community-acquired pneumonia (CAP), and specifically in patients with PncCAP, to those in patient groups with other respiratory diseases. We studied patients aged ≥65 years with radiologically confirmed CAP, clinical CAP not retrospectively radiologically confirmed, other acute respiratory infections, or stable chronic lung disease. Pneumococcal etiology of CAP was ascertained by using a combination of multiple diagnostic methods. We analyzed sputum and NPS specimens by lytA qPCR with 104 pneumococcal genome equivalents (GE)/ml as a cutoff for positivity. Among PncCAP patients, lytA qPCR detected pneumococci in 94% of the sputum samples and in large quantities (mean, 6.82 ± 1.02 log10 GE/ml) but less frequently in NPS (44%) and in smaller quantities (5.55 ± 0.92 log10 GE/ml). In all other patient groups, ≤10% of the sputum samples and <5% of the NPS samples were lytA qPCR positive; but when they were positive, the sputum pneumococcal loads were similar to those in the PncCAP patients, suggesting a pneumococcal etiology in these patients. This was supported by other pneumococcal assay results. Overall, sputum lytA qPCR positivity was more common in PncCAP patients than in the other patient groups, but the quantitative results were mainly similar. NPS lytA qPCR was less sensitive than sputum lytA qPCR in detecting PncCAP.

Chagas disease and liver transplantation: Experience in Argentina using real-time quantitative PCR for early detection and treatment.

Chagas disease (CD) is an endemic zoonosis that occurs in Latin America and is caused by the parasite Trypanosoma cruzi. Early detection of T.cruzi in liver transplant recipients at risk may avoid complications from CD. The aim of this study was to examine the pre-operative evaluation and follow-up of CD after liver transplantation (LT) of patients at risk of CD using real-time quantitative polymerase chain reaction (qPCR) for T.cruzi. Between January 2009 and June 2016, 13 (12.7%) of 102 LTs performed in recipients at risk for CD without specific postoperative prophylaxis were prospectively evaluated using qPCR for T.cruzi. Four seronegative patients received livers from seropositive donors (R-/D+) and 9 seropositive recipients received livers from seronegative donors (R+/D-). A cohort of 89 patients without risk for CD during the same time period was analyzed as controls. A positive qPCR for T.cruzi prior to LT was found in 2/9 (22.2%) seropositive recipients, and both achieved early response after therapy. The cumulative incidence of positive parasitemia after LT was higher in R+/D- than R-/D+ (37.7% vs 0%, P=.17). R+/D- transplant patients with positive qPCR achieved therapeutic response without manifestations of acute CD. LT outcomes at 1year were similar in patients at risk of CD and in controls not at risk for CD. A small proportion of T.cruzi-seropositive candidates presented positive parasitemia before LT. After LT, qPCR allowed detection of parasitemia leading to use of preemptive therapy in all R+/D- with T.cruzi replication. No cases of T.cruzi parasitemia occurred in R-/D+.

O-5S quantitative real-time PCR: a new diagnostic tool for laboratory confirmation of human onchocerciasis

BackgroundOnchocerciasis is a parasitic disease caused by the filarial nematode Onchocerca volvulus. In endemic areas, the diagnosis is commonly confirmed by microscopic examination of skin snip samples, though this technique is considered to have low sensitivity. The available melting-curve based quantitative real-time PCR (qPCR) using degenerated primers targeting the O-150 repeat of O. volvulus was considered insufficient for confirming the individual diagnosis, especially in elimination studies. This study aimed to improve detection of O. volvulus DNA in clinical samples through the development of a highly sensitive qPCR assay.MethodsA novel hydrolysis probe based qPCR assay was designed targeting the specific sequence of the O. volvulus O-5S rRNA gene. A total of 200 clinically suspected onchocerciasis cases were included from Goma district in South-west Ethiopia, from October 2012 through May 2013. Skin snip samples were collected and subjected to microscopy, O-150 qPCR, and the novel O-5S qPCR.ResultsAmong the 200 individuals, 133 patients tested positive (positivity rate of 66.5%) and 67 negative by O-5S qPCR, 74 tested positive by microscopy (37.0%) and 78 tested positive by O-150 qPCR (39.0%). Among the 133 O-5S qPCR positive individuals, microscopy and O-150 qPCR detected 55.6 and 59.4% patients, respectively, implying a higher sensitivity of O-5S qPCR than microscopy and O-150 qPCR. None of the 67 individuals who tested negative by O-5S qPCR tested positive by microscopy or O-150 qPCR, implying 100% specificity of the newly designed O-5S qPCR assay.ConclusionsThe novel O-5S qPCR assay is more sensitive than both microscopic examination and the existing O-150 qPCR for the detection of O. volvulus from skin snip samples. The newly designed assay is an important step towards appropriate individual diagnosis and control of onchocerciasis.

Cytomegalovirus Management in Adult Hematopoietic Stem Cell Transplant Patients with Pre-Engraftment Viremia: A Single-Center, Retrospective, Descriptive Study

BackgroundScant data exist regarding cytomegalovirus (CMV) viremia in hematopoietic stem cell transplant (HSCT) recipients during the pre-engraftment period. The goal of this study was to describe management of CMV in neutropenic adult HSCT patients at our institution, and to assess the possible impact of different quantitative CMV PCR tests (QPCRs).MethodsPost-HSCT monitoring at this center includes weekly CMV QPCR from plasma. Three different QPCR assays were used sequentially during the study period (1/2010–12/2015): two with lower limits of quantification (LLOQ) of 300 and 100 copies/mL through 4/2013, and after that the FDA-approved assay with LLOQ of 137 IU/mL. Medical records of first-time HSCT patients were reviewed. Pre-/peri-engraftment CMV was defined as detectable CMV DNA with [ANC] < 1000 cells/mm3. Information collected included demographics, donor/recipient CMV serostatus, conditioning regimen, CMV QPCR and ANC results, dates of CMV treatment, CMV disease within 100 days, and death within 6 months of HSCT. Data were analyzed with STATA v14.ResultsOf 1151 total HSCT, 76 patients had a positive CMV QPCR when ANC < 1000 cells/mm3. CMV was first detected a median of 12 days (0–48) post-transplant, and was above LLOQ at a median of 28 days (0–49). 71/76 (93%) were treated at a median of 33 days post-transplant (range 4–105 days), most with valganciclovir (40) or ganciclovir (30); 1 received foscarnet initially. 5 patients with low-level viremia were monitored without treatment. At initiation of therapy, median CMV level was 1471 (range 159–22,900) copies or IU/mL and ANC was 1202 (range 28–9680) cells/mm3. Median treatment duration was 34 days (range 9–392). Only 2 patients had possible tissue-invasive CMV disease.ConclusionGanciclovir and valganciclovir were used to treat most pre- and peri-engraftment CMV viremia, despite potential bone marrow toxicity. The LLOQ of different CMV QPCR tests did not affect the viral threshold for starting treatment. The time between first CMV DNA detection (median day +12) and initiation of treatment (median day +33) suggests clinicians waited for CMV DNA and/or ANC to rise before treating. With this deferred-treatment approach, the proportion of patients with tissue-invasive disease remained low.Disclosures All authors: No reported disclosures.

Use of a commercial qPCR assay in 52 high risk shelter cats for disease identification of dermatophytosis and mycological cure.

qPCR is used to test for dermatophytosis. To determine the clinical usefulness of a commercial qPCR for confirming dermatophytosis in lesional cats, and the clinical usefulness of the qPCR Microsporum spp. and/or M. canis assay for confirming mycological cure. Fifty two shelter cats with skin lesions. qPCR testing of toothbrush fungal culture samples of lesions. qPCR and fungal culture (FC) matched in 49 of 52 cats. The qPCR correctly identified 45 of 46 and two of four cats with M. canis and Trichophyton spp. infections, respectively. qPCR correctly identified two cats as not infected. No evidence of cross reactivity was noted. The Microsporum spp. qPCR assay was positive in 45 of 46 (97.8%) of infected cats. Results were positive on both Microsporum spp. and M. canis assays in 29 of 45 cats. No cat had a positive qPCR result for M. canis alone. Mycological cure was defined as two negative fungal cultures. There were 92 negative FC from the 46 treated cats and qPCR assay for Microsporum spp. and M. canis was negative in 68 of 92 (73.1%) and 79 of 92 (85.9%) samples, respectively. The number of cats correctly identified with mycological cure via qPCR was 30 of 46 (65.2%) and 39 of 46 (84.8%) cats for the Microsporum spp. and M. canis assays, respectively. The commercial qPCR assay was a reliable test for confirming disease. The qPCR Microsporum spp. assay was more useful for initial disease confirmation; while the qPCR M. canis assay was more useful for determining mycological cure.

Clinical Utility of Quantitative PCR for Chimerism and Engraftment Monitoring after Allogeneic Stem Cell Transplantation for Hematologic Malignancies

Although quantitative PCR (qPCR) has been explored for chimerism monitoring after allogeneic stem cell transplantation (SCT), evidence regarding its clinical utility compared with standard short tandem repeat (STR) is still limited. We retrospectively studied commercial qPCR and STR chimerism with respective positivity thresholds of .1% and 1% in 359 peripheral blood (PB) and 95 bone marrow (BM) samples from 30 adult patients after first HLA-matched SCT for myeloid malignancies or acute lymphatic leukemia. Concordance between the 2 methods was 79.5%, with all discordant samples positive in qPCR but negative in STR. Of the latter, sporadic qPCR positivity without clinical correlates was seen mostly in BM samples early post-transplant. In 7 of 21 patients with available follow-up samples in the first months after transplantation, qPCR but not STR revealed low levels (<1%) of sustained host chimerism in PB, reflecting delayed engraftment or persistent mixed chimerism (PMC). These conditions were associated with donor–recipient cytomegalovirus (CMV) serostatus and early CMV reactivation but not with immunosuppressive regimens or clinical outcome. qPCR predicted all 8/8 relapses with samples in the 6 months before onset by sustained positivity in both PB and BM compared with 1/8 relapses predicted by STR mainly in BM. The response kinetics to donor lymphocyte infusions for the treatment of PMC or relapse was shown by qPCR but not STR to be protracted over several months in 3 patients. Our results demonstrate the superior clinical utility of qPCR compared with STR for monitoring subtle changes of host chimerism associated with different clinical conditions, making a case for its use in the clinical follow-up of transplant patients.

Evaluation of the involvement of mice (Mus musculus) in the epidemiology of porcine proliferative enteropathy

The aim of this study was to evaluate the fecal-oral transmission of L. intracellularis between mice and pigs. The study was divided into two parts. The first part aimed to determine whether mice could be infected by feces from pigs that are experimentally infected with L. intracellularis. Thirty-four Swiss mice received L. intracellularis PCR-positive feces from experimentally infected pigs (M1) for four consecutive days. Twelve other mice received swine negative feces (M2). Pools of mice feces were collected on alternating days post-exposure (dpe). The second part of the study aimed to test whether pigs could be infected when exposed to L. intracellularis PCR-positive feces from experimentally infected mice. Twelve 5-week-old pigs received feed mixed with L. intracellularis PCR-positive mice feces (P1), while the other two pigs received PCR-negative mice feces (P2) for four consecutive days. In the first study, the amount of L. intracellularis provided to M1 boxes per day was between 106 and 108. Mice shed, an average of 104 bacterial units every collection day. Three mice from M1 were positive for L. intracellularis by immunohistochemistry (IHC) at the end of the study. In the second part of the study, pigs in P1 received an average of 105 bacterial units per day. Ten pigs were infected by L. intracellularis based on positive qPCR and/or immunohistochemistry and serology results. These pigs shed an average of 104L. intracellularis/g of feces. Mice and pigs experimentally infected with L. intracellularis can infect each other, therefore, rodents should be considered players in the epidemiology of this disease in pig farms.

Adenovirus-Associated Acute Appendicitis: An Under-Recognized Relationship?

Acute appendicitis (AA) is one of the most common causes of a surgical abdomen worldwide, occurring most frequently in those age 10 to 29 years. Adenovirus (ADV) is a rare but reported cause of AA in children and a well-recognized cause of intussusception in infants and young children. Annually, about 36,000 basic military trainees (BMTs) undergo initial training at Joint Base San Antonio Lackland, Texas. Before reintroduction of the ADV 4/7 vaccine in November 2011, one-third of BMTs developed an adenoviral upper respiratory tract infection (URI) during the 8.5 weeks of training. We hypothesized that ADV may be a common cause of AA in the BMT population given their young age and high incidence of adenoviral URIs. The objective of this study was to determine the frequency with which ADV, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and enterovirus were associated with AA in a population of young adults. This study was a retrospective review of patient charts and existing pathological tissue specimens of all BMTs who underwent appendectomy at the Wilford Hall Medical Center from January 1, 2003, to August 31, 2011. Pathological tissue samples from 112 BMTs were assayed by quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) for viral targets. ADV DNA was detected in 16 of 112 samples (14%) via qPCR: ADV 4 in 13 cases, ADV B14 in 1 case, and nontypable ADV in 2 cases. IHC was positive in only the ADV B14 case (0.9%). All cases were negative for CMV, EBV, and enterovirus. By using qPCR, this study demonstrated an association between ADV and AA higher than has been previously reported: ADV was detected in 14% of AA cases in this series versus in only 0.23% of AA cases in previous studies (p < 0.01). There was no evidence of CMV, EBV, or enterovirus association with AA in this study. Comparison of qPCR to IHC shows that histologic analysis may overlook evidence of ADV in appendiceal tissue: qPCR is significantly more sensitive than light microscopy and IHC for detecting ADV in this setting. Because ADV 4 was detected in 81% of those with positive qPCR, the recently licensed live oral ADV vaccine might be useful for primary prevention against AA. Prospective studies evaluating young adults presenting with AA for evidence of infection with ADV are needed to determine if a causal relationship exists.

Canine leptospirosis in Switzerland—A prospective cross-sectional study examining seroprevalence, risk factors and urinary shedding of pathogenic leptospires

Leptospirosis is an important worldwide zoonosis. While human leptospirosis remains rare in Switzerland, the incidence of canine leptospirosis is unusually high compared to other European countries. The aims of this cross-sectional study were to determine the exposure of asymtomatic dogs to pathogenic Leptospira in Switzerland, to characterise risk factors associated with seropositivity and to determine the prevalence of urinary shedding. Sampling was stratified to cover the whole of Switzerland. Sera were tested by microscopic agglutination test for antibodies against a panel of 12 serovars. Urine was tested for pathogenic Leptospira using a LipL32 real-time PCR. Of 377 sera, 55.7% (95%CI 51.2–60.7) showed a reciprocal MAT titre of ≥1:40 and 24.9% (95%CI 20.7–29.4) of ≥1:100 to at least one serovar. Seropositivity (MAT ≥1:100) was most common to serovars Australis (14.9%; 95% CI 11.4–18.6) and Bratislava (8.8%; 95%CI 6.1–11.7), followed by Copenhageni (6.1%; 95%CI 3.7-8.5), Canicola (5%; 95%CI 2.9–7.4), Grippotyphosa (4.5%; 95%CI 2.7–6.9), Pomona (4%; 95%CI 2.1–6.1), Autumnalis (2.7%; 95%CI 1.3–4.2) and Icterohaemorrhagiae (1.6%; 95%CI 0.5-2.9). In unvaccinated dogs (n=84) the prevalence of a MAT titre ≥100 was 17.9% (95%CI 10.7–26.2), with a similar distribution of reactive serovars. Variables associated with seropositivity (≥1:40) to any serovar included age (OR 1.29/year; 95%CI: 1.1–1.5) and bioregion with higher risks in the regions Northern Alps (OR 14.5; 95%CI 2.2–292.7), Central Plateau (OR 12.3; 95%CI 2.0–244.1) and Jura (OR 11.2; 95%CI 1.7–226.7) compared to Southern Central Alps. Dogs living with horses were significantly more likely to have antibodies to serovar Bratislava (OR 4.68;95%CI 1.2–17.2). Hunting was a significant risk factor for seropositivtiy to serovar Grippotyphosa (OR 8.03; 95%CI 1.6–30.8). Urine qPCR positivity was uncommon (1/408 dogs; 0.2%; 95% CI0–0.7). These results demonstrate that dogs in Switzerland are commonly exposed to pathogenic Leptospira; however, the risk of dogs contributing to the spread of Leptospira in the environment appears low.

Strategies for reducing the risk of transfusion-transmitted leishmaniasis in an area endemic for Leishmania infantum: a patient- and donor-targeted approach.

In the Balearic Islands, as in other areas of the Mediterranean basin, there is a significant proportion of asymptomatic Leishmania (L.) infantum-infected blood donors, who may represent an important threat to transfusion safety. The Balearic Islands blood bank, located in an area endemic for L. infantum, carried out a study of donors and patients to investigate the impact of this infectious disease on blood safety in the region. Twenty asymptomatic Leishmania-infected blood donors were followed-up between 2008 and 2011 to investigate the evolution of Leishmania infection in asymptomatic carriers. Their blood was periodically tested for anti-Leishmania antibodies by western blot and for Leishmania DNA by quantitative polymerase chain reaction (qPCR). Additionally, the prevalence of L. infantum infection was investigated in a group of 68 multiply transfused patients to ascertain the risk of transfusion-transmitted leishmaniasis (TTL) in the region, taking into account regular blood component production practices such as pre-storage leucodepletion and pathogen reduction technology. All 20 donors remained asymptomatic over the study period (2008-2011). Most donors had repeatedly positive qPCR results, either persistently or intermittently, but showed no symptoms of Leishmaniasis. Levels of parasitaemia were remarkably low in asymptomatic donors, with values ≤1 parasite/mL. Despite multiple transfusions received over 15 years, no transfused patient studied was infected with L. infantum. L. infantum-infected donors can remain asymptomatic for at least 3 years. In our region, no cases of TTL were detected, despite an active search in multiply transfused patients. This seems to be related to two independent variables: (i) a low concentration of the parasite in the peripheral blood of asymptomatic carriers and (ii) the application of methods with proven efficacy against TTL, such as leucodepletion and pathogen reduction technology.