Dual shape recovery of red blood cells flowing out of a microfluidic constriction

Micropipette aspiration, optical tweezers, rheometry, or ecktacytometry have been used to study the shape recovery of healthy human Red Blood Cells (RBCs) and measure associated relaxation times of the order of 100-300 ms. These measurements are in good agreement with the Kelvin-Voigt model, which describes the cell as a visco-elastic material, predicting that its relaxation time only depends on cell intrinsic properties. However, such mechanical solicitation techniques are far from being relevant regarding RBC solicitation in vivo. In this paper, we report for the first time the existence of two different behaviors of the RBC shape recovery while flowing out of a microfluidic constricted channel. The calculation of the viscous stress corresponding to the frontier between the two recovery modes confirms that the RBC resistance to shear μ is the elastic property dominating the transition between the two recovery behaviors. We also quantified associated recovery times τ r and report values as low as 4 ms-which is almost two decades smaller than the typical RBC relaxation time-at high viscosity and flow velocity of the carrier fluid. Although we cannot talk about relaxation time because the cell is never at rest, we believe that the measured shape recovery time arises from the coupling of the cell intrinsic deformability and the hydrodynamic stress. Depending on the flow conditions, the cell mechanics becomes dominant and drives the shape recovery process, allowing the measurement of recovery times of the same order of magnitude than relaxation times previously published. Finally, we demonstrated that the measurement of the shape recovery time can be used to distinguish Plasmodium falciparum (causing malaria) infected RBCs from healthy RBCs.

[Fungal keratitis: A 5-year monocentric retrospective study on Reunion Island]

OBJECTIVES

Fungal keratitis is rare in France, but could be a severe sight-threatening condition. Here, we aimed to describe the epidemiology of fungal keratitis in Réunion Island.

METHODS

In a retrospective study, we analyzed 13 culture-proven keratitis episodes, occurred between January 2013 and July 2017 in the ophthalmology ward of a University Hospital, Saint-Pierre. Twelve isolates were genotyped and antifungal susceptibility testing was performed.

RESULTS

Corneal abrasion caused by vegetable matter was the main predisposing factor. Stromal infiltration was observed in 12 patients. Six patients did not response to medical treatment, requiring surgical care, including two enucleations surgery. Fusarium solani (n = 6) and Fusarium dimerum (n = 4) were the main fungal species involved in fungal keratitis. Clinical failures were more prevalent with F. solani infections. The lowest minimal inhibitory concentrations for Fusarium sp. were observed with voriconazole and amphotericin B.

CONCLUSION

In Reunion Island, the epidemiology of fungal keratitis is characterized by the predominance of Fusarium species, potentially involved in visual loss. This pattern is consistent with the epidemiology usually observed in tropical areas.

From phaeohyphomycosis to disseminated chromoblastomycosis: A retrospective study of infections caused by dematiaceous fungi

OBJECTIVE

Infections caused by dematiaceous fungi are more common in tropical and subtropical areas. We aimed to describe the clinical, microbiological and therapeutic aspects of case patients diagnosed at a University Hospital located on an Indian Ocean island.

PATIENTS AND METHODS

We performed an observational retrospective study of infections caused by dematiaceous fungi diagnosed at the University Hospital of Saint-Pierre, Reunion, from 2000 to 2015. Mycological identifications were performed at the National Reference Center for Invasive Mycosis and Antifungal Agents (Paris).

RESULTS

The review of clinical and microbiological data of 11 patients identified revealed that five were infected by dematiaceous fungi. Two had cutaneous phaeohyphomycosis, two had cerebral phaeohyphomycosis and one had cutaneous chromoblastomycosis with brain and potentially medullary dissemination. Skin lesions and cerebral abscesses were quite varied.

CONCLUSION

Infections caused by dematiaceous fungi are rare. Medullary and brain localizations are extremely rare, especially for chromoblastomycosis. Cutaneous manifestations of phaeohyphomycosis are varied; diagnosis is thus more difficult. It is therefore important, when confronted with a chronic tumor-like lesion in endemic areas, to perform a biopsy for pathology and fungal culture. While surgical excision is not always sufficient, medical treatment of these infections is not standardized, but relies on an azole, which can be associated with another antifungal agent.

Surveillance of carbapenemase-producing Enterobacteriaceae in the Indian Ocean Region between January 2010 and December 2015

BACKGROUND

The aim of this study was to trace the emergence of carbapenemase-producing Enterobacteriaceae (CPE) on Reunion Island, a French overseas territory well suited for the surveillance of CPE emergence in patients from the entire Indian Ocean Region.

METHODS

This retrospective multicenter study was conducted on Reunion Island between 2010 and 2015.

RESULTS

A total of 43 CPEs were isolated during the course of the study, in 36 patients (50% in the last year alone). Among these patients, 21 had a link with a foreign country (58%), mainly Mauritius (47.6%). Over the same period, CPEs were isolated from 13 of 1735 (0.7%) repatriated patients to Reunion Island from another country of the Indian Ocean Region. The incidence of isolation of CPEs in the repatriated patients treated in Mauritius was higher (9.2%) than in patients treated in Madagascar or the Comoros Islands (<1%, P<0.001). The most commonly isolated microorganism was Klebsiella pneumoniae (39.5%). The most frequently identified carbapenemase was NDM-1 (81.4%); 100% and 56% of the NDM-1 strains were susceptible to tigecycline and colistin, respectively. In-hospital mortality rate was higher in patients presenting with CPE infection than in patients without CPE infection (75% vs. 25%, P=0.04).

CONCLUSION

As elsewhere in the world, the number of CPE cases on Reunion Island is on the rise. Most cases involve patients from Mauritius, which justifies screening and isolating CPE in patients from that country.

A multicenter, randomized, open-label, controlled study comparing the efficacy, safety and cost-effectiveness of a sequential therapy with RV4104A ointment, ciclopiroxolamine cream and ciclopirox film-forming solution with amorolfine nail lacquer alone in dermatophytic onychomycosis

BACKGROUND

The efficacy of topical antifungals is controversial.

OBJECTIVE

To compare the efficacy and safety of a sequential(SEQ) treatment with chemical nail avulsion and topical antifungals to amorolfine nail lacquer in dermatophytic onychomycosis.

METHODS

This was a randomized,parallel-group, controlled study comparing a 36-week SEQ treatment with chemical nail avulsion with RV4104A ointment(class I medical device containing 40% urea) followed by ciclopirox cream for 8 weeks and ciclopirox nail lacquer for 25 weeks (SEQ group) to amorolfine nail lacquer for 36 weeks (AMO group). Patients had to have a big toenail onychomycosis,sparing the matrix. The primary efficacy criterion was complete cure at week 48. A cost-effectiveness analysis was performed.

RESULTS

A total of 142 patients were randomized. The complete cure rate at week 48 was significantly higher in the SEQ group than in the AMO group (36.6 vs. 12.7%, p = 0.001). Clinical cure at week 48 was observed in 53.5% of patients in the SEQ group versus 17% in the AMO group (p < 0.01). The cost of cure per patient was 50% lower with SEQ treatment (EUR 33) compared with amorolfine(EUR 76).

CONCLUSION

A treatment of onychomycosis comprising chemical avulsion of the pathological nail, ciclopirox cream and nail lacquer is significantly more effective than amorolfine nail lacquer.

[Molecular diagnosis by real-time PCR of Leishmania isolated from the Phlebotomus vector]

The authors report the demonstration of Leishmania in the tissue of Phlebotomus samples captured in the region of Constantine in 2010. The four species that could be identified were: Phlebotomus larroussius, P. perfiliewi, P. longicuspis, and Sergentomyia minuta.

[Determinants of group B streptococcus maternal colonization and factors related to its vertical perinatal transmission: case-control study]

OBJECTIVES

To investigate the determinants of Group B streptococcus (GBS) maternal colonization, as well as factors associated with its vertical transmission.

PATIENTS AND METHODS

Case-control study on all singletons pregnancies delivered beyond at least 24 weeks of amenorrhoea in Southern Reunion maternities for which GBS screening was known. Multiple logistic regression analysis using 2004-2007 dataset of South Reunion birth registers.

RESULTS

Out of 17,430 women delivered between 1st January 2004 and 31st December 2007, 2911 (16.7%) carried GBS. In a model adjusted on antenatal care, risk groups for GBS carriage were the women indigenous from another island of the Indian Ocean than Reunion (OR: 1.29, CI95%: 1.05-1.57) and obese women (body mass index ≥ 30, OR: 1.19, CI95%: 1.03-1.18). Protective factors included birthplace in mainland France (OR: 0.82, CI95%: 0.69-0.97) and underweight (OR: 0.81; CI95%: 0.69-0. 95). In a model controlling for a composite obstetrical variable delineating the protective roles of C-section and antibioprophylaxis as well as the putative role of meconium-stained fluids (thin, thick or fetid), all previously found in our setting, three key factors were independently associated with GBS vertical mother-to-child transmission: obesity (OR: 1.48, CI95%: 1.05-2.09), fetal tachycardia (OR: 4.92, CI95%: 2.79-8.68) and late preterm birth (35 to 36 wks, OR: 2.14, CI95%: 1.32-3.45).

CONCLUSION

These findings strengthen the putative roles of corpulence and ethnicity in GBS acquisition previously found in the United States, while confirming an authentic role of obesity in its vertical transmission, independently of other classical cofactors lighted by our study.

[Evolution of resistance to antibiotics from 1997 to 2005 in the Reunion Island]

OBJECTIVE

The groupe hospitalier Sud Reunion (GHSR) is a 1130-bed hospital center, located on the Reunion Island, (Indian Ocean). We studied the profiles of antibiotic resistance in 2005, and compared those with previous data collected in 1997-1998, and with Metropolitan France and European data.

MATERIAL AND METHODOLOGY

All bacteriological strains isolated from diagnostic samples in 2005 were analyzed according to CA-SFM recommendations.

RESULTS

Since 1997, the rates of resistance to enterobacteria (betalactam, aminoside, quinolone, trimethoprim-sulfamethoxazole), Pseudomonas aeruginosa (ticarcillin, amikacin, ciprofloxacin, fosfomycin), Acinetobacter baumanii (amikacin) has decreased significantly. The rate of methicillin-resistant Staphylococcus aureus (1997: 3.6 %, 2005: 13.4 %) has increased but less than in Metropolitan France. The rate of Streptococcuspneumonia with decreased susceptibility to penicillin has increased (1997: 25.5 %, 2005: 42.9 %), as for Haemophilusinfluenzae which present an important increase of betalactam resistance (1997: 15.5 %, 2005: 37.8 %).

CONCLUSION

By comparing our data to 1997 and Metropolitan French data, it seems that the GHSR has managed to protect its hospital-based microbial ecology. However, community germs showed increasing resistance, probably because of an increasing antibiotic pressure, but with resistance rates often inferior to Metropolitan French ones.

The mariner transposable element in natural populations of Drosophila simulans

In cosmopolitan species, geographical variations in copy number and/or level of transposition activity have been observed for several transposable elements (TEs). Environment, history and population structure can contribute to such variation in ways that are difficult to tease apart. For the mariner element, previous studies of the geographic variation of its somatic activity in natural populations of Drosophila simulans have shown contradictory results (latitudinal clines of divergent orientations or no apparent structure). To try and resolve these inconsistencies, we gathered all available data on the mariner somatic activity of worldwide natural populations. This includes previously published results by different groups and also new data. The correlations between the level of activity and several geoclimatic factors were tested. Although no general effect of temperature was found, a relationship with the invasion history was detected. It was also shown that recent invasive populations have a higher level of activity than the putative ancestral ones. Our results strongly suggest that variability of the mariner somatic activity among natural populations of D. simulans is mainly due to populational and historical factors probably related to the recent world colonization of this species. Indeed, this activity is correlated to the main route out of Africa (the Nile route) and the recent colonization of continents such as Australia and South America.

Validation of a viral and bacterial inactivation step during the extraction and purification process of porcine collagen

In the last few years, regulations for biomolecule production, and especially for extraction and purification of animal molecules such as collagen, have been reinforced to ensure the sanitary safety of the materials. To be authorized to market biomaterials based on collagen, manufacturers now have to prove that at least one step of their process is described in guidelines to inactivate prion, viruses, and bacteria. The present study focuses on the inactivation step performed during the extraction and purification of porcine type I atelocollagen. We chose to determine the reduction factor of a 1 M NaOH step on porcine parvovirus and four bacterial strains inactivation. During the extraction step, we deliberately inoculated the collagen suspension with the different microorganisms tested. Then, 1 M NaOH was added to the suspension for 1 hour at 20 degrees C. We demonstrated that this treatment totally inactivated S. aureus, P. aeruginosa, C. albicans and A. niger which are bacterial strains responsible of severe human pathology. The reduction factors reached more than 4 logs for B. cereus spores and 4 logs for the porcine parvovirus. are encouraging as those two microorganisms are known to be very resistant to inactivation.

Toxoplasma gondii: Comparison of human CD34+ and monocyte-derived dendritic cells after parasite infection

Human dendritic cells (DC) obtained in vitro from CD34(+) progenitors (CD34-DC) or blood monocytes (mo-DC) are different DC which may be used in a model of T. gondii infection. We compared the survival, infection rate and cell surface receptor expression of both DC types after living T. gondii tachyzoite infection. CD34-DC appeared less resistant to the parasite than mo-DC. At 48h post-infection, chemokine receptors responsible for DC homing and migration were absent in mo-DC, while down regulation of CCR6 and up regulation of CCR7 was observed in CD34-DC. This result, suggesting migration ability of CD34-DC, was confirmed by in vitro migration experiments against different chemokines. Tachyzoite supernatant, used as chemokine, attracted immature CD34-DC as observed by MIP3alpha, while MIP3beta, as expected, attracted mature CD34-DC. Under similar conditions, no significant difference was noticed between mature or immature mo-DC. These data indicated that CD34-DC represent an alternative model that allows migration assay of infected DC by T. gondii.

Disseminated cryptococcosis and histoplasmosis co-infection in a HIV-infected woman in France

We report the first case in Europe of co-infection with disseminated cryptococcosis and histoplasmosis. The diagnosis of invasive histoplasmosis was confirmed by microscopic examination of the anatomic right colon specimen (hemicolectomy). Histoplasma antigen detection is not yet available in France but it could have a key role in the early diagnosis of disseminated histoplasmosis co-existing with a cryptococcal infection, especially in HIV-infected African people.

[Is Plasmodium vivax still a paradigm for uncomplicated malaria?]

P. vivax is supposed to be involved in benign tertian fever, responsible for a non-complicated disease that could be easily treated by standard antimalarial drug regimen. This could be considered as a long-standing paradigm of a non-virulent malaria parasite. When a patient exhibits severe malaria with the vivax parasite, the issue is often to find falciparum. However, with the implementation of molecular diagnosis, it has becoming more evident that vivax parasites could be involved in severe disease with probably a different pathogenesis. Mixed infections are frequent in various parts of Southeast Asian endemic areas and it was speculated that drugs used to treat falciparum could be involved in the development of vivax drug resistance. How should primaquine be used today for the treatment and prophylaxis of vivax malaria? Considering the re-emergence of vivax malaria in several areas, improving the treatment for this disease is certainly an important issue to avoid late episodes and transmission potential.

[Apoptosis and programmed cell death. Host parasite relationship new paradigm]

Apoptosis and programmed cell death are amongst the most fascinating new concepts for understanding the host-parasite relationship. A growing body data is raising questions about the impact of the death of an individual parasite on the survival of the parasite population as a whole. Does the parasite induce the death of the host cell as an expression of virulence or does it inhibit that death as a factor for transmissibility? Current evidence that these effects are mediated through specific highly regulated mechanisms suggest that deciphering programmed cell death could provide new tools for control of parasitic diseases.

[Outsourced real-time PCR diagnosis of cutaneous leishmaniasis in the outbreak region of Constatine, Algeria]

Taking into account the re-emergence of leishmaniasis in the world, the geographic variability of its epidemiology and the growing numbers of travellers, a pilot study on the diagnosis of cutaneous leishmaniasis was undertaken in Constatine, one of the outbreak regions in eastern Algeria. A total of 143 specimens were collected on blotters and tested by real-time PCR. Results were compared with those of direct examination. Diagnosis was positive for leishmaniasis in 81% of cases using PCR versus 48% of cases using microscopy. Real-time PCR showed a significant quantitative difference between patients for whom microscopic diagnosis was positive and those for whom direct examination was negative. The results presented in this study demonstrated the effectiveness and sensitivity of PCR in the diagnosis of cutaneous leishmaniasis from blotter specimens. This technique enabled in-field collection of specimens from each patient and provided prompt results. North-South cooperation based on the use of simple means for transmission of specimens for molecular diagnosis allowed creation of an effective partnership for daily diagnosis and promoted exchange between investigators in preparation for technology transfer.

[Antimicrobial resistance of Streptococcus pneumoniae strains isolated in the Reunion Island during 2004]

OBJECTIVE AND METHOD

Available data from the Southern Reunion Island Medical Group was processed to assess the evolution of Streptococcus pneumoniae resistance to antibiotics since 1994 when the first penicillin-non-susceptible S. pneumoniae (PNSSP) was identified. In addition, 249 strains, isolated between 1998 and 2004, were tested against telithromycin and moxifloxacin.

RESULTS

Between 1994 and 2004, the percentage of PNSSP increased from 0 to 59.2%. Among PNSSP, 13.9% were resistant strains in 2004 with MICs<4 microg/ml. Before 2001 the rate of resistance to penicillin was superior to 50%. In 2004, 15.8 and 8.7% of the isolated strains were of decreased susceptibility to amoxicillin and cefotaxime respectively while none were resistant to either treatment. Other antibiotics followed the pattern of resistance to penicillin. Between 1998 and 2004, resistance to erythromycin decreased from 42.5 to 35.1%, from 35.1 to 22.8% for cyclins, from 18.8 to 8.8 for chloramphenicol, and from 38.3 to 12.3% for cotrimoxazole. All tested strains were susceptible to both telithromycin and moxifloxacin.

CONCLUSION

Amoxicillin remains efficient for all strains isolated in the Reunion Island in 2004. The presence of strains with decreased susceptibility to third generation cephalosporins implies combination with vancomycin for empirical treatment of pneumococcal meningitis. Moxifloxacin can be used when using a fluoroquinolone is justified. Telithromycin is efficient even on strains resistant to erythromycin and consequently this molecule can be prescribed in the case of a required macrolide treatment.

[Lymphocytis meningitis: Listeria monocytogenes is a potential risk in a immunocompetent child]

Meningoencephalitis due to Listeria monocytogenes is a rare and serious form of brainstem infection in childhood.

OBSERVATION

We report the case of a 7 year-old girl presenting lymphocytic meningitis with a high CRP level. Parenteral antibiotics combining ceftriaxone and vancomycine led initially to clinical improvement. Ten days later, secondary brainstem inflammation with hydrocephalus appeared and led to the detection of L. monocytogenes during external ventricular bypass.

CONCLUSION

This observation of paediatric lymphocytic meningoencephalitis suggests a prescription of amoxicillin in association with first line antibiotics, particularly when an important inflammatory syndrome exists, immunocompetent children included.

Toxoplasma gondii regulates recruitment and migration of human dendritic cells via different soluble secreted factors

We investigated in vitro the properties of soluble factors produced by Toxoplasma gondii on the recruitment, maturation and migration of human dendritic cells (DC) derived from CD34+ progenitor cells. We used soluble factors including excreted secreted antigens (ESA) produced under various conditions by the virulent type I RH strain (ESA-RH) and the less virulent PRU type II strain (ESA-PRU). Soluble factors of both T. gondii strains appeared to possess a chemokine-like activity that attracted immature DC. This recruitment activity required the presence of functional CCR5 molecules on the cell membrane. Incubation of DC for 24 h with ESA triggered the migration of a large percentage of these cells towards the chemokine MIP-3beta; ESA-PRU was more efficient than ESA-RH. ESA produced in absence of exogenous protein and crude extract did not induce DC migration but retained recruitment activity. These data indicate that recruitment activity and migration-inducing activity are not governed by the same factors. Moreover, incubation of DC for 48 h with ESA did not modify the expression of costimulation or maturation markers (CD83, CD40, CD80, CD86 or HLA-DR), but induced a decrease in CCR6 expression associated with an increased expression of CCR7. Taken together, these results suggest that T. gondii controls recruitment and migration of immature DC by different soluble factors and may induce a dysfunction in the host-specific immune response.

Candida species distribution in bloodstream cultures in Lyon, France, 1998–2001

In order to determine the types of Candida spp. isolated from bloodstream cultures in Lyon, France, a retrospective study of isolates collected at five different bacteriology laboratories from 1998 to 2001 was conducted. During this period Candida spp. were isolated from 190 patients hospitalized in the internal medicine (32%), hematology (23%) and surgery (23%) wards, and in intensive care units (22%). C. albicans was the leading cause of Candida infection (49.5%), followed by C. glabrata (12.6%) and C. parapsilosis (12.1%). Among the onco-hematology patients, the major cause of candidemia was C. krusei (34%), followed by C. albicans (19%), while these two species were identified in 4% and 59% of patients in the other wards, respectively. In the single onco-hematology ward that was specialized in treating acute myeloid leukemia, 14 C. krusei isolates were identified in this study, which contrasts with the single C. krusei isolate recorded between 1992 and 1996. Since C. krusei has inherent resistance to the antifungal agent fluconazole, prophylactic use of fluconazole in these patients was investigated, but no relationship between these two parameters was found.

Absence of nucleotide polymorphism in a Plasmodium vivax multidrug resistance gene after failure of mefloquine prophylaxis in French Guyana

Vivax malaria is widespread and resistance has been described for chloroquine and sulfadoxine-pyrimethamine. We report on evidence of failure of mefloquine prophylaxis in a French soldier who contracted Plasmodium vivax in French Guyana, South America. Despite regular weekly mefloquine prophylaxis (250 mg/d), the patient presented with a first episode of vivax malaria, which was treated by chloroquine alone, then experienced a second crisis in France. The reappearance of the parasites occurred one day after the end of prophylaxis, confirming parasitological and clinical resistance in a non-immune patient. Mefloquine was detected by a liquid chromatography assay in plasma at a level of 1062 ng/ml, which was higher than the expected concentration after five months of weekly prophylaxis. This isolate had no single nucleotide polymorphisms of the pvmdr1 gene at seven allele positions: pvmdr1 N91, Y189, Y976, S1071, F1076, N1079 and D1291, corresponding to codons 86, 184, 939, 1034, 1039, 1042 and 1246 in P. falciparum. This observation of failure of mefloquine prophylaxis against P. vivax, when added to previously reported chloroquine and atovaquone-proguanil failure, strengthens the case for re-evaluating drug policies for vivax malaria and the need for continuous research on molecular markers of drug resistance.

Comparative diagnostic performance of two commercial rapid tests for malaria in a non-endemic area

In the study reported here, the diagnostic performance of two new rapid tests for the diagnosis of malaria was evaluated in symptomatic patients in a non-endemic area. Of 557 consecutive patients, 109 (19.6%) had documented malaria. For the NOW ICT MALARIA P.f./P.v. (Binax, Portland, ME, USA) and OptiMAL IT (Diamed, Cressier, Switzerland) tests, respectively, sensitivity values were 96.3% and 79.8% (P-value, 0.0001), and specificity values were 98.8% and 98.4%. The NOW ICT test did not detect two of 80 Plasmodium falciparum infections, and it generated false-positive results for five patients. The OptiMAL IT test failed to detect ten of the P. falciparum infections, and it generated seven false-positive results. The results suggest that these rapid diagnostic tests for malaria may be useful, but they cannot replace microscopic examination of blood films.

Heterogeneity in cellular and humoral immune responses against Toxoplasma gondii antigen in humans

Protection against Toxoplasma gondii in infected patients is mainly attributed to cellular immunity. We here attempt to improve the characterization of the proteins that induce cellular immunity in naturally infected patients. Cellular immunity was evaluated by flow cytometry after 7 days of blood culture from 31 chronically T. gondii infected and 8 noninfected pregnant women, in the presence of soluble T. gondii antigen (ST-Ag) or fractionated proteins from ST-Ag, separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Blood cultures from infected patients with ST-Ag induced 39.5 +/- 12.7% of activated (CD25+) CD4+ T cells using flow cytometry. This contrasts with the absence of activated CD4+ T cells after either culture with PBS or in blood cultures from noninfected women. The protein fraction between 21 and 41.9 kD induced the highest response (14.7 +/- 10.0%). Blood samples from 20 infected and 5 uninfected women were cultured in presence of 12 protein subfractions of 2-208 kD. The highest frequencies of response among infected patients were seen with fractions (Fr) 26-31.9 kD (C.I. 85-100%) and Fr 32-36.9 kD (C.I. 77-100%). Although we note a good concordance between cellular and humoral response, Western blot analysis of ST-Ag does not completely predict the panel of proteins recognized by cellular immunity. Two-dimensional separation of the ST-Ag revealed more than 200 protein spots in these fractions. However, only two proteins in the 20-40 kD range induced a significant humoral response. Further studies are necessary to determine which proteins in the Fr 26-31.9 kD and 32-36.9 kD are superior immunogens for cellular responses.

Severe peritonitis due to Balantidium coli acquired in France

The case reported here concerns an alcoholic pork-butcher who presented with severe colitis with peritonitis, caused by the only ciliate protozoan capable of infecting humans, Balantidium coli. This parasite is common in a variety of domestic and wild mammals, mainly pigs; however, its prevalence rate in humans is very low--particularly in industrialised, northern countries, including France. The infection is most frequently acquired by ingesting food or water contaminated by pig faeces, and it may be asymptomatic or may cause acute diarrhoea. Specific antibiotic treatment is efficacious, and it is important to consider the risk of this parasitic disease in susceptible patients presenting with bloody diarrhoea.

[Real-time PCR for detection of molecular markers of resistance in Plasmodium falciparum]

Plasmodium falciparum drug resistance is a major problem in malaria endemic areas. Molecular markers and in vitro tests have been developed to study and monitor drug resistance. However, none used alone, can provide sufficient data concerning the level of drug resistance and to issue precise guideline for drug use policies in endemic areas. We propose real-time PCR for the simultaneous detection of pfcrt and pfmdr1 genes mutations. The aim of this study was not to provide definitive data concerning the rate of mutations in an endemic area, but to describe a powerful method allowing the detection of major pfmdr1 and pfcrt mutations.

Synergistic and antagonistic interactions between haemozoin and bacterial endotoxin on human and mouse macrophages

Haemozoin (malaria pigment) is a birefringent crystalline material made of Fe (III) Protoporphyrin IX dimers that derives from the degradation of haemoglobin by intraerythrocytic Plasmodia. At schizont rupture, it accumulates indigested inside phagocytic cells altering their immunological properties. Both pro-inflammatory and immunosuppressive activities have been associated with pigment-fed monocyte-macrophages or dendritic cells. These conflicting results were attributed to the source of macrophages or the different preparations of pigment. However, the interactions of malaria pigment with other phagocytes stimuli, such as bacterial endotoxin (LPS) or interferon-gamma have not been fully analysed, yet. The purpose of this study was to compare the immunological properties of native haemozoin (HZ), freshly extracted from Plasmodium falciparum cultures, versus beta-haematin (BH), the synthetic crystals identical to native haemozoin, and to evaluate the relationship between haemozoin and endotoxin on the immune response of different macrophages populations. The results indicate that the iron-porphyrin moiety of both native and synthetic pigment can exert either a synergistic or antagonistic effect with LPS that is related to the length and sequence of treatment, the source of macrophages and is associated with the generation of oxidative stress. These data rise the question of whether and how in vivo concomitant gram(-) bacteremia may affect the pathogenesis and/or the immune response of malaria infections and vice versa.

Binding of live conidia of Aspergillus fumigatus activates in vitro-generated human Langerhans cells via a lectin of galactomannan specificity

Aspergillus fumigatus is the most common aetiological fungus responsible for human pulmonary aspergilloses. This study investigated the primary contact between Langerhans cells (LC), corresponding to dendritic cells present in pulmonary mucosa and live conidia of A. fumigatus. LC play a key role in antigen presentation for initiation of the primary T cell response. In vitro-generated LC (iLC) were differentiated from cultured human cord blood CD34+ cells and incubated at 4 degrees C or 37 degrees C with fluorescein-isothiocyanate (FITC)-stained conidia or control latex beads. In vitro, conidia were shown by microscopy and cytometry to adhere to iLC in a dose- and time-dependent manner. This adhesion was not limited to iLC because interstitial dendritic and other cells also fluoresced in the presence of conidia-FITC. A lectin other than mannose receptor-type lectin was demonstrated to be responsible of conidial binding. Inhibition of binding was observed with heterologous galactomannan and EDTA, indicating a C-lectin-like receptor with galactomannan structure specificity. After binding only a few conidia were internalized in acidic vesicles, as indicated by the cessation of conidial fluorescence. Conidial binding was followed by activation and maturation of iLC, suggesting that LC present in the lung may play a role in cellular host defence against aspergilloses.

Evaluation of different commercial ELISA methods for the serodiagnosis of systemic candidosis

Different commercial enzyme-linked immunsorbent assays (ELISA) were evaluated in a preliminary study for diagnosis of systemic candidosis: Biomerica and Virotech GmbH, which allowed immunoglobulin G detection, and Platelia, which associated total antibody to antigen detection. They were tested with a home-made ELISA and compared with the routine techniques used in the hospital laboratory: indirect immunofluorescence and counter-immunoelectrophoresis. Sera were obtained from patients with probable or proven systemic candidosis (groups 3 and 4, n=8 and n=14, respectively) and from patients without systemic candidosis who were divided into controls (n=10), those hospitalized without Candida isolation (group 1, n=10) and those hospitalized with Candida isolation in a peripheral site (group 2, n=18). The immunoglobulin G ELISAs showed a higher sensitivity associated with lower specificity compared to the indirect immunofluorescence, counter-immunoelectrophoresis and total immunoglobulin ELISAs. Mannan antigen detection showed the highest specificity (78.9%). Its association with the detection of total anti-Candida immunoglobulins was more sensitive than the association of indirect immunofluorescence with counter-immunoelectrophoresis (95.4% versus 59%, respectively) with a specificity of 52.6% (versus 55.2%). Interest in the use of commercial ELISAs, more particularly the Platelia tests, has to be confirmed in a prospective study with follow-up of the patients.