Interlaboratory evaluation of Mucorales PCR assays for testing serum specimens: A study by the fungal PCR Initiative and the Modimucor study group

Interlaboratory evaluations of Mucorales qPCR assays were developed to assess the reproducibility and performance of methods currently used. The participants comprised 12 laboratories from French university hospitals (nine of them participating in the Modimucor study) and 11 laboratories participating in the Fungal PCR Initiative. For panel 1, three sera were each spiked with DNA from three different species (Rhizomucor pusillus, Lichtheimia corymbifera, Rhizopus oryzae). For panel 2, six sera with three concentrations of R. pusillus and L. corymbifera (1, 10, and 100 genomes/ml) were prepared. Each panel included a blind negative-control serum. A form was distributed with each panel to collect results and required technical information, including DNA extraction method, sample volume used, DNA elution volume, qPCR method, qPCR template input volume, qPCR total reaction volume, qPCR platform, and qPCR reagents used. For panel 1, assessing 18 different protocols, qualitative results (positive or negative) were correct in 97% of cases (70/72). A very low interlaboratory variability in Cq values (SD = 1.89 cycles) were observed. For panel 2 assessing 26 different protocols, the detection rates were high (77-100%) for 5/6 of spiked serum. There was a significant association between the qPCR platform and performance. However, certain technical steps and optimal combinations of factors may also impact performance. The good reproducibility and performance demonstrated in this study support the use of Mucorales qPCR as part of the diagnostic strategy for mucormycosis.

Unexpected persistence of extended-spectrum β-lactamase-producing Enterobacteriaceae in the faecal microbiota of hospitalised patients treated with imipenem

Imipenem is active against extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) but favours the intestinal emergence of resistance. The effects of imipenem on intestinal microbiota have been studied using culture-based techniques. In this study, the effects were investigated in patients using culture and metagenomic techniques. Seventeen hospitalised adults receiving imipenem were included in a multicentre study (NCT01703299, http://www.clinicaltrials.gov). Most patients had a history of antibiotic use and/or hospitalisation. Stools were collected before, during and after imipenem treatment. Bacterial and fungal colonisation was assessed by culture, and microbiota changes were assessed using metagenomics. Unexpectedly, high colonisation rates by imipenem-susceptible ESBL-E before treatment (70.6%) remained stable over time, suggesting that imipenem intestinal concentrations were very low. Carriage rates of carbapenem-resistant Gram-negative bacilli (0-25.0%) were also stable over time, whereas those of yeasts (64.7% before treatment) peaked at 76.5% during treatment and decreased thereafter. However, these trends were not statistically significant. Yeasts included highly diverse colonising Candida spp. Metagenomics showed no global effect of imipenem on the bacterial taxonomic profiles at the sequencing depth used but demonstrated specific changes in the microbiota not detected with culture, attributed to factors other than imipenem, including sampling site or treatment with other antibiotics. In conclusion, culture and metagenomics were highly complementary in characterising the faecal microbiota of patients. The changes observed during imipenem treatment were unexpectedly limited, possibly because the microbiota was already disturbed by previous antibiotic exposure or hospitalisation.

Aspergillus spp. invasive external otitis: favourable outcome with a medical approach

Aspergillus spp. invasive external otitis (IEO) is a rare infection. We performed a seven-year, single-centre retrospective study from 2007 to 2014 including all patients with proven Aspergillus spp. IEO. Twelve patients were identified. All patients had a poorly controlled diabetes mellitus and one underwent solid organ transplant. The most frequently isolated species was Aspergillus flavus (n = 10) and voriconazole was the first-line therapy in all cases, with a median length of treatment of 338.5 days (158-804 days). None of the patients underwent extensive surgery. The clinical outcome was excellent. However, otological sequelae were reported, including hearing impairment (n = 7) and facial palsy (n = 3).

Matrix-assisted laser desorption ionization-time of flight mass spectrometry for fast and accurate identification of Pseudallescheria/Scedosporium species

An increasing number of infections due to Pseudallescheria/Scedosporium species has been reported during the past decades, both in immunocompromised and immunocompetent patients. Additionally, these fungi are now recognized worldwide as common agents of fungal colonization of the airways in cystic fibrosis patients, which represents a risk factor for disseminated infections after lung transplantation. Currently six species are described within the Pseudallescheria/Scedosporium genus, including Scedosporium prolificans and species of the Pseudallescheria/Scedosporium apiospermum complex (i.e. S. apiospermum sensu stricto, Pseudallescheria boydii, Scedosporium aurantiacum, Pseudallescheria minutispora and Scedosporium dehoogii). Precise identification of clinical isolates at the species level is required because these species differ in their antifungal drug susceptibility patterns. Matrix-assisted laser desorption ionization (MALDI)-time of flight (TOF)/mass spectrometry (MS) is a powerful tool to rapidly identify moulds at the species level. We investigated the potential of this technology to discriminate Pseudallescheria/Scedosporium species. Forty-seven reference strains were used to build a reference database library. Profiles from 3-, 5- and 7-day-old cultures of each reference strain were analysed to identify species-specific discriminating profiles. The database was tested for accuracy using a set of 64 clinical or environmental isolates previously identified by multilocus sequencing. All isolates were unequivocally identified at the species level by MALDI-TOF/MS. Our results, obtained using a simple protocol, without prior protein extraction or standardization of the culture, demonstrate that MALDI-TOF/MS is a powerful tool for rapid identification of Pseudallescheria/Scedosporium species that cannot be currently identified by morphological examination in the clinical setting.

Microsporidiosis in solid organ transplant recipients: two Enterocytozoon bieneusi cases and review

Microsporidiosis first came to prominence as an opportunistic infection in patients with acquired immunodeficiency syndrome. Microsporidia are now emerging pathogens responsible for severe diarrhea during solid organ transplantation. Two main clinical entities can be identified: infection by Enterocytozoon bieneusi, causing diarrhea with limited treatment options; and infection by Encephalitozoon intestinalis, which may disseminate and usually responds to albendazole treatment. We describe here 2 cases of microsporidiosis caused by E. bieneusi in a renal and a liver transplant recipient, respectively, in whom complete clinical efficacy of a short course of fumagillin therapy was obtained. Long-term microbiological eradication was assessed using classical methods and monitored using a real-time quantitative polymerase chain reaction-based method. Both patients experienced drug-induced thrombocytopenia, which resolved after withdrawal of the treatment. We also review the 18 other previously reported cases of microsporidiosis in transplant recipients. In case of persistent diarrhea in solid organ transplant patients, microsporidiosis should be considered. Based on the present experience, treating E. bieneusi infection with 7 days of fumagillin therapy is adequate to eradicate E. bieneusi in this context.

Mycetoma of the foot caused by Fusarium solani: identification of the etiologic agent by DNA sequencing

We report a case of Fusarium solani mycetoma of the foot that could not be diagnosed by culture, but was correctly identified after amplification and sequence analysis of fungal internal transcribed spacers 1 and 2 and 5.8S ribosomal DNA regions.

An outbreak of acute pulmonary histoplasmosis in members of a trekking trip in Martinique, French West Indies

BACKGROUND

Thirteen clustered cases of American histoplasmosis, a deep mycosis caused by Histoplasma capsulatum and acquired through inhalation of airborne spores was reported. Twenty-five persons traveled in Martinique, French West Indies. Thirteen underwent trekking and passed through a mountain tunnel full of bats (tunnel group). The 12 others performed canyoning and did not go through the tunnel (control group). Fifteen days after exposure, 1 patient of the tunnel group developed fever, chills, and cough.

METHODS

The index case was diagnosed in the hospital, but 12 cases where initially diagnosed as prolonged influenza. All individuals were contacted and submitted to a phone questionnaire. They were asked about eventual occurrence of influenzalike symptoms, about activities practiced, and the notion of contact with bats. All were invited to have clinical examinations, chest x-ray films, and blood samplings. Serologic testing for histoplasmosis was performed by immunodiffusion. Clinical evidence of infection with H. capsulatum was obtained in all the remaining patients of the tunnel group and in none in the control group. Symptoms occurred with an acute onset in 11 to 23 days: fever and chills, severe asthenia, headaches, digestive tract involvement, and then cough, dyspnea, hepatic involvement. Pulmonary micro- or macronodules and mediastinal adenopathies were seen on radiograph and/or computed tomography scan.

RESULTS

H. capsulatum serologic tests were positive in all 13 cases with presence of specific M and or H precipitins, 5 to 13 weeks after exposure, and were negative in control group. All patients were treated with itraconazole 200 mg per day during at least 2 months. Treatment was well tolerated; patients progressively recovered. Clinical and serologic follow-up was obtained for some patients at 1 and 4 years. The present study reports the first large outbreak of histoplasmosis acquired in Martinique.

CONCLUSION

Histoplasmosis still occurs and is potentially serious. In patients returning from endemic areas, presenting prolonged influenzalike symptoms, clinicians should look for previous possible exposure to Histoplasma.

Comparative genetic diversity of parasites and their hosts: population structure of an urban cockroach and its haplo-diploid parasite (oxyuroid nematode)

Few studies have investigated the genetic structure of both host and parasite populations at a level of populations and at a level of individuals. We investigated the genetic structure of the urban cockroach Blattella germanica and its oxyuroid parasite Blatticola blattae. Random amplified polymorphic DNA (RAPD) markers were used to quantify genetic diversity between and within four populations (from two cities in France) of the host and its parasite. Diversity based on phenotypic frequencies was calculated for each RAPD marker using Shannon-Wiener's index. We used multivariate analyses to test the significance of genetic differentiation between host and parasite populations. Analysis of molecular variance was also used. Both methods gave similar results. Diversity between pairs of individuals was estimated by Nei & Li's index. Genetic diversity was higher within host or parasite populations (80% and 82%, respectively, of explained diversity) than between host or parasite populations (20% and 18%, respectively, explained diversity). The genetic distances between pairs of parasite populations (or individuals) were not correlated with the genetic distances between the corresponding pairs of host populations (or individuals).

Genetic diversity among Trichophyton mentagrophytes isolates using random amplified polymorphic DNA method

Trichophyton mentagrophytes is a common cosmopolitan dermatophyte species composed of two varieties: T. mentagrophytes var. interdigitale (anthropophilic form) and T. mentagrophytes var. mentagrophytes (zoophilic form). We used a random amplified polymorphic DNA (RAPD) method to study the genetic diversity of 46 clinical isolates of the T. mentagrophytes complex collected from 38 patients with different geographical origins (Europe, Africa, South America). The T. mentagrophytes were isolated either from a unique lesion for 31 patients, including two patients living together, or from at least two sites for seven patients. Only one primer of 15 primers tested showed DNA polymorphism in the isolates, producing 23 distinct patterns belonging to three clusters. There was no specific cluster grouping isolates from the same geographical origin. The same pattern is shared by all the four T. mentagrophytes var. mentagrophytes and 13 of 42 T. mentagrophytes var. interdigitale. An identity of strains responsible for several lesions in seven individuals suggests an homogeneous T. mentagrophytes population in the case of multiple lesions. In contrast, the dissimilarity of two strains recovered from two patients living together argues against person-to-person transmission in that case. This study indicates that RAPD can be successfully applied to show genetic diversity among T. mentagrophytes isolates.

Use of random amplified polymorphic DNA (RAPD) for generating specific DNA probes for oxyuroid species (Nematoda)

Random amplified DNA markers (RAPD; Williams et al., 1990) were used to obtained specific RAPD fragments characterising different species of oxyuroids. We tested six species of worms parasitizing vertebrates or invertebrates: Passalurus ambiguus Rudolphi, 1819, parasite of Leporids; Syphacia obvelata (Rudolphi, 1802) Seurat, 1916, a parasite of rodents; Blatticola blattae (Graeffe, 1860) Chitwood, 1932 parasite of the cockroach Blattella germanica; Hammerschmidtiella diesingi (Hammerschmidt, 1838) Chitwood, 1932 and Thelastoma bulhoesi (Magalhaes, 1990) Travassos, 1929, parasites of the cockroach Periplaneta americana, and an undescribed parasite species of a passalid insect from New Caledonia. Among 15 oligonucleotides tested, nine produced several specific bands allowing the interspecific discrimination.

Mixed Candida glabrata and Candida albicans disseminated candidiasis in a heroin addict

The case of a white-heroin addict who developed disseminated candidiasis following coinfection by Candida glabrata and Candida albicans is reported. Genomic random amplified polymorphic DNA typing suggested that the Candida glabrata blood isolates originated in the oral cavity of the patient. This case strengthens the evidence that Candida species other than Candida albicans can be involved in the pathogenesis of disseminated candidiasis in heroin addicts.

Ivermectin and moxidectin in two filarial systems: resistance of Monanema martini; inhibition of Litomosoides sigmodontis insemination

Effects of ivermectin and moxidectin were compared on two filarial species: Monanema martini which presents dermal microfilariae and induces Onchocerca-like lesions in its natural murid host Lemniscomys striatus, and Litomosoides sigmodontis (= L. carinii). M. martini microfilariae showed an unusual resistance to ivermectin, in vitro and in vivo; moxidectin was no more efficient. However, the two drugs used at high concentrations deeply altered the uterine embryogenesis, but had no lethal effect on adult filariae. L. sigmodontis blood microfilariae showed a great susceptibility to moxidectin, similar to that previously described for ivermectin. The two drugs also induced a long term effect because they inhibited the insemination of the female filariae. This result reinforces the observations made by other authors on the human parasite, Onchocerca volvulus.

Microbiological findings about pulmonary cryptosporidiosis in two AIDS patients

There is no known treatment for pulmonary cryptosporidiosis, a rare complication of intestinal cryptosporidiosis in AIDS patients. We report two cases of cryptosporidiosis which were unusual because (i) extracellular invasive forms of the parasite were found in the bronchoalveolar lavage and (ii) the outcome was favorable in one patient after treatment with azithromycin.

Use of random amplified polymorphic DNA as a typing method for Candida albicans in epidemiological surveillance of a burn unit

Burn patients are particularly exposed to deep-seated nosocomial infections caused by Candida species. Superficial carriage of C. albicans is a potential source of infection and dissemination, and typing methods could be useful to trace the different isolates. We report the use of random amplified polymorphic DNA to type isolates of C. albicans in the Hôpital Cochin burn unit. This molecular typing method, which is based on PCR with arbitrary short primers, was evaluated on a panel of 32 C. albicans strains isolated from various anatomical sites of unrelated patients, and the strains showed 22 different patterns. Random amplified polymorphic DNA was then used in the epidemiological surveillance of the patients in the burn unit over a 9-month period. Seven patterns were identified among 84 isolates from 18 patients. One pattern (pattern A) corresponding to isolates from 7 of the 18 patients (68% of isolates) predominated throughout the 9-month study, while some strains with other profiles were isolated only once. Some profiles appeared to show a particular geographic pattern within the unit, suggesting transmission from room to room. These results underline the importance of fungal surveillance in such patients and the need to inform nursing staff of measures to prevent the spread of Candida spp. from patient to patient.

Resolutive Candida utilis fungemia in a nonneutropenic patient

We report here the second case of Candida utilis infection in humans. The patient was apparently immunocompetent, had no central catheter, and survived an 8-day fungemia. Genomic analysis confirmed the conspecificity of medical and industrial strains of C. utilis and that of the anamorphic yeast C. utilis with the teleomorphic yeast Pichia jadinii.

[Diagnosis of cerebral toxoplasmosis in AIDS patients. Value of antibodies evaluation in cerebrospinal fluid]

The purpose of this study was to evaluate the diagnostic value of search for intrathecally synthesized specific antibodies in cerebral toxoplasmosis. Intrathecal synthesis of antibodies was measured by calculating the immunity load coefficient (ILC) in both serum and cerebrospinal fluid. In this retrospective study the records of 42 AIDS patients with clinically on the basis of computerized tomography and therapeutic results, and was excluded in 31 patients (control group). Specific immunoglobulins G were found in the cerebrospinal fluid of 9 out of the 11 patients with toxoplasmosis, but also in 14 of the 31 controls. Since ILC measurements in serum and cerebrospinal fluid identified 7/11 cases other hand, since the ILC value was higher than the positivity threshold in controls, the specificity of the test was assessed at 68 percent.

Comparison of antibody, antigen, and metabolite assays for hospitalized patients with disseminated or peripheral candidiasis

Repeat serum samples from 22 patients with proven disseminated candidiasis and 42 with simple peripheral colonization were assayed for Candida antibodies by coelectrosyneresis, immunoprecipitation, and A and B immunofluorescence, for metabolites by D-arabinitol measurement, and for antigens by the mannan immunoassay and Cand-tec latex agglutination (mean number of samples tested, 2.5 per patient). For the antibody and metabolite assays, the results showed no statistical difference between the two groups. By contrast, the results of both antigen assays were positive for a significantly larger number of patients with disseminated candidiasis than of those with simple peripheral colonization. Results were regardless of whether the patients were neutropenic. They were not predictive of death. We calculated that the mannan antigen assay had 29% sensitivity and 97% specificity for the diagnosis of disseminated candidiasis. Likelihood ratios of a positive and a negative result of this test were 9.2 and 0.7, respectively, for this diagnosis. In the latex agglutination test, likelihood ratios were 2.5, 1.5, 1.6, and 0.3 when the test was positive for dilutions of 1/8, 1/4, and 1/2 and was negative, respectively.

Two outbreaks of trichinosis caused by horsemeat in France in 1985

Two outbreaks of trichinosis occurred in France in August and October of 1985 and 1,073 cases in all were identified. In the first outbreak, two localities were involved: the town of Melun and the 14th district of Paris. To determine the origin of the contamination, three case-control studies were carried out: among patients' families, among the populations of these two areas, and among the inmates in the prison of Melun. In the second outbreak, cases again occurred in Paris but in a different district (the 12th), in the city's suburbs, and in other towns scattered throughout France. Although no parasites were found in any of the meat examined in either outbreak, results of the study indicate that infection was due to horsemeat consumption and led to the incrimination of two carcasses, one imported from a slaughterhouse in the United States and the other from West Germany. These findings led the French Ministry of Agriculture to order the inspection for trichinosis of all meat from horses slaughtered both in France and in countries exporting horsemeat to France.

Randomized trial of albendazole versus tiabendazole plus flubendazole during an outbreak of human trichinellosis

To determine the therapeutic usefulness of benzimidazoles in trichinellosis, 117 patients from a single outbreak were treated either with albendazole alone (N = 59) or with a regimen including tiabendazole followed by flubendazole (N = 58). The criteria of disease activity were evaluated at days 1, 7, 15, and 45. No difference was found between the two groups with regard to the evolution of myalgia, fever, fatigue, new clinical manifestations, or laboratory and serologic data. Both treatment regimens were well tolerated. In all, 30 patients of the albendazole group and 29 of the tiabendazole-flubendazole group were reevaluated 16 months later. Serology was negative in 70% of the albendazole-treated patients vs 34.5% of the tiabendazole-flubendazole-treated patients (P less than 0.01). The muscle biopsy examination of nine patients suggested less parasitic infection in the albendazole group. In conclusion, no difference was noted during the early therapeutic responses to the drugs used, but albendazole might be more effective than the other regimen in treating residual larval infestation estimated 16 months after the onset of the disease.