Ruling out nosocomial transmission of Cryptosporidium in a renal transplantation unit: case report

Background

Cryptosporidium spp. is a ubiquitous parasite affecting humans as well as domestic and wild vertebrates, causing diarrhea in both immunocompetent and immunocompromised hosts worldwide. Its transmission occurs primarily by the fecal-oral route. In humans, C. parvum and C. hominis are the most prevalent species, whereas immunocompetent and immunocompromised individuals can also be infected by other zoonotic species. Renal transplant patients are prone to develop cryptosporidiosis, which can induce severe and life-threatening diarrhea.

Case presentation

We report here a series of nearly concomitant cases of acute symptomatic cryptosporidiosis in three renal transplant patients attending the Strasbourg University Hospital Nephrology Unit. The clinical presentation was persistent diarrhea and acute renal failure. The diagnosis was confirmed by microscopic stool examination using a modified Ziehl-Neelsen staining method and species identification by molecular tools. All patients were treated with nitazoxanide and recovered from diarrhea after 14 days of therapy.

Conclusion

Genotypic species identification was not consistent with an epidemic context, thus underlining the need for genotyping to monitor at risk patients.

Prevalence and Risk Factors for Intestinal Protozoan Infections with Cryptosporidium, Giardia, Blastocystis and Dientamoeba among Schoolchildren in Tripoli, Lebanon

BACKGROUND

Intestinal protozoan infections are confirmed as major causes of diarrhea, particularly in children, and represent a significant, but often neglected, threat to public health. No recent data were available in Lebanon concerning the molecular epidemiology of protozoan infections in children, a vulnerable population at high risk of infection.

METHODOLOGY AND PRINCIPAL FINDINGS

In order to improve our understanding of the epidemiology of intestinal pathogenic protozoa, a cross-sectional study was conducted in a general pediatric population including both symptomatic and asymptomatic subjects. After obtaining informed consent from the parents or legal guardians, stool samples were collected in January 2013 from 249 children in 2 schools in Tripoli, Lebanon. Information obtained from a standard questionnaire included demographic characteristics, current symptoms, socioeconomic status, source of drinking water, and personal hygiene habits. After fecal examination by both microscopy and molecular tools, the overall prevalence of parasitic infections was recorded as 85%. Blastocystis spp. presented the highest infection rate (63%), followed by Dientamoeba fragilis (60.6%), Giardia duodenalis (28.5%) and Cryptosporidium spp. (10.4%). PCR was also performed to identify species and genotypes of Cryptosporidium, subtypes of Blastocystis, and assemblages of Giardia. Statistical analysis using a logistic regression model showed that contact with family members presenting gastrointestinal disorders was the primary risk factor for transmission of these protozoa.

CONCLUSIONS

This is the first study performed in Lebanon reporting the prevalence and the clinical and molecular epidemiological data associated with intestinal protozoan infections among schoolchildren in Tripoli. A high prevalence of protozoan parasites was found, with Blastocystis spp. being the most predominant protozoans. Although only 50% of children reported digestive symptoms, asymptomatic infection was observed, and these children may act as unidentified carriers. This survey provides necessary information for designing prevention and control strategies to reduce the burden of these protozoan infections, especially in children.

Pilot-Scale Pulsed UV Light Irradiation of Experimentally Infected Raspberries Suppresses Cryptosporidium parvum Infectivity in Immunocompetent Suckling Mice

Cryptosporidium spp., a significant cause of foodborne infection, have been shown to be resistant to most chemical food disinfectant agents and infective for weeks in irrigation waters and stored fresh vegetal produce. Pulsed UV light (PL) has the potential to inactivate Cryptosporidium spp. on surfaces of raw or minimally processed foods or both. The present study aimed to evaluate the efficacy of PL on viability and in vivo infectivity of Cryptosporidium parvum oocysts present on raspberries, a known source of transmission to humans of oocyst-forming apicomplexan pathogens. The skin of each of 20 raspberries was experimentally inoculated with five 10-μl spots of an oocyst suspension containing 6 × 10(7) oocysts per ml (Nouzilly isolate). Raspberries were irradiated by PL flashes (4 J/cm(2) of total fluence). This dose did not affect colorimetric or organoleptic characteristics of fruits. After immunomagnetic separation from raspberries, oocysts were bleached and administered orally to neonatal suckling mice. Seven days after infection, mice were euthanized, and the number of oocysts in the entire small intestine was individually assessed by immunofluorescence flow cytometry. Three of 12 and 12 of 12 inoculated mice that received 10 and 100 oocysts isolated from nonirradiated raspberries, respectively, were found infected. Four of 12 and 2 of 12 inoculated mice that received 10(3) and 10(4) oocysts from irradiated raspberries, respectively, were found infected. Oocyst counts were lower in animals inoculated with 10(3) and 10(4) oocysts from irradiated raspberries (92 ± 144 and 38 ± 82, respectively) than in animals infected with 100 oocysts from nonirradiated raspberries (35,785 ± 66,221, P = 0.008). PL irradiation achieved oocyst reductions of 2 and 3 log for an inoculum of 10(3) and 10(4) oocysts, respectively. The present pilot-scale evaluation suggests that PL is an effective mode of decontamination for raspberries and prompts further applicability studies in industrial contexts.

Assessment of microscopic and molecular tools for the diagnosis and follow-up of cryptosporidiosis in patients at risk

Cryptosporidiosis is an important though underreported public health concern. Molecular tools might be helpful in improving its diagnosis. In this study, ZR Fecal DNA MiniPrep™ Kit (ZR) and NucliSens® easyMAG® (EM) were compared using four Cryptosporidium-seeded feces and 29 Cryptosporidium-positive stools. Thereafter, ZR was selected for prospective evaluation of Cryptosporidium detection by 18S rDNA and LAXER quantitative PCR (qPCR) in 69 stools from 56 patients after Cryptosporidium detection by glycerin, modified Ziehl-Neelsen (ZN) and auramine-phenol (AP) stainings. The combination of any of the two extraction methods with 18S qPCR yielded adequate detection of Cryptosporidium in seeded stools, but the ZR kit showed the best performance. All 29 Cryptosporidium-positive samples were positive with 18S qPCR, after both ZR and EM extraction. However, false-negative results were found with LAXER qPCR or nested PCR. Cryptosporidiosis was diagnosed in 7/56 patients. All the microscopic methods enabled the initial diagnosis, but Cryptosporidium was detected in 12, 13, and 14 samples from these seven patients after glycerin, ZN, and AP staining respectively. Among these samples, 14 and 12 were positive with 18S and LAXER qPCR respectively. In two patients, Cryptosporidium DNA loads were found to be correlated with clinical evolution. Although little known, glycerin is a sensitive method for the initial detection of Cryptosporidium. When combined with 18S qPCR, ZR extraction, which had not been evaluated so far for Cryptosporidium, was an accurate tool for detecting Cryptosporidium and estimating the oocyst shedding in the course of infection.

Semi-automated repetitive sequence-based PCR amplification for species of the Scedosporium apiospermum complex

PURPOSE

The Scedosporium apiospermum species complex usually ranks second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF), but little is known about the molecular epidemiology of the airway colonization.

METHODS

Polymerase chain reaction (PCR) amplification of repetitive sequences (rep-PCR) was applied to the retrospective analysis of a panel of isolates already studied by random amplification of polymorphic DNA (RAPD) and comprising 63 isolates recovered from sputa from 9 CF patients. Results were compared to those obtained previously by RAPD, and herein by beta-tubulin (TUB) gene sequencing and Multilocus Sequence Typing (MLST).

RESULTS

Within the panel of isolates studied,S. apiospermum sensu stricto and Scedosporium boydii, as expected, were the predominant species with 21 and 36 isolates, respectively. Four isolates from one patient were identified as Scedosporium aurantiacum, whereas two isolates belonged to the Pseudallescheria ellipsoidea subgroup of S. boydii rep-PCR analysis of these isolates clearly differentiated the three species and P. ellipsoidea isolates, whatever the rep-PCR kit used, and also permitted strain differentiation. When using the mold primer kit, results from rep-PCR were in close agreement with those obtained by MLST. For both S. apiospermum and S. boydii, 8 genotypes were differentiated by rep-PCR and MLST compared to 10 by RAPD. All S. aurantiacum isolates shared the same RAPD genotype and exhibited the same rep-PCR profile and sequence type.

CONCLUSIONS

These results illustrate the efficacy of rep-PCR for both species identification within the S. apiospermum complex and genotyping for the two major species of this complex.Abstract presentation: Part of this work was presented during the 18th Congress of the International Society for Human and Animal Mycology, Berlin (Germany), June 2012.S. Giraud, C. Godon, A. Rougeron, J.P. Bouchara and L. Favennec are members of the ECMM/ISHAM working group on Fungal respiratory infections in Cystic Fibrosis(Fri-CF).

Rasamsonia argillacea species complex: taxonomy, pathogenesis and clinical relevance

Since 2010, colonizations/infections by Rasamsonia argillacea species complex, previously known as Geosmithia argillacea, have been regularly reported in literature. We reviewed all available cases focusing on pathogenesis and clinical relevance. The number of cases may be underestimated, as these fungi are frequently misidentified as Penicillium or Paecilomyces species. Major underlying conditions that predispose for infections by the R. argillacea species complex include cystic fibrosis (CF) and chronic granulomatous disease (CGD). While the pathogenic role of the colonization of CF lungs is still under debate, these molds are the causative agent of pneumonia and/or invasive infections in CGD patients. Given their thermotolerance and their resistance to various antifungals, especially the azole drugs, a special attention should be paid to the chronic colonization of the airways by these fungi in CF and CGD patients.

Protozoa interaction with aquatic invertebrate: interest for watercourses biomonitoring

Toxoplasma gondii, Cryptosporidium parvum, and Giardia duodenalis are human waterborne protozoa. These worldwide parasites had been detected in various watercourses as recreational, surface, drinking, river, and seawater. As of today, water protozoa detection was based on large water filtration and on sample concentration. Another tool like aquatic invertebrate parasitism could be used for sanitary and environmental biomonitoring. In fact, organisms like filter feeders could already filtrate and concentrate protozoa directly in their tissues in proportion to ambient concentration. So molluscan shellfish can be used as a bioindicator of protozoa contamination level in a site since they were sedentary. Nevertheless, only a few researches had focused on nonspecific parasitism like protozoa infection on aquatic invertebrates. Objectives of this review are twofold: Firstly, an overview of protozoa in worldwide water was presented. Secondly, current knowledge of protozoa parasitism on aquatic invertebrates was detailed and the lack of data of their biological impact was pointed out.

Clinical and microbiological efficacy of micafungin on Geosmithia argillacea infection in a cystic fibrosis patient

Cystic fibrosis (CF) patients are at high risk of colonization of the airways by a number of fungi, including the emerging opportunistic fungus Geosmithia argillacea. We report the eradication of respiratory G. argillacea associated with clinical resolution of severe symptoms by high-dose and prolonged micafungin therapy in a young CF patient.

Effects of octreotide on jejunal hypersensitivity triggered by Cryptosporidium parvum intestinal infection in an immunocompetent suckling rat model

BACKGROUND

Similar to other bacterial or protozoan infections, human cryptosporidiosis may trigger postinfectious irritable bowel syndrome (IBS)-like symptoms, a condition in which enhanced visceral perception of pain during intestinal distension plays a pivotal role. In an immunocompetent suckling rat model which mimicks features of postinfectious IBS, Cryptosporidium parvum infection induces long-lasting jejunal hypersensitivity to distension in association with intestinal activated mast cell accumulation. The aim of the present study was to explore in this model whether octreotide, a somatostatin agonist analog, could prevent the development of jejunal hypersensitivity and intestinal mast cell/nerve fiber accumulation.

METHODS

Five-day-old Sprague-Dawley rats were infected with C. parvum and treated 10 days later with octreotide (50 g kg(-1) day(-1), i.p.) for 7 days.

KEY RESULTS

Compared with untreated infected rats, octreotide treatment of infected rats resulted in increased weight gain [day 23 postinfection (PI)], decreased food intake (day 16 PI), and a reduction in jejunal villus alterations (day 14 PI), CD3(+) IEL (day 37 PI) and mast cell (days 37 and 50 PI) accumulations, nerve fiber densities (day 50 PI), and hypersensitivity to distension (day 120 PI). In uninfected rats, the effects of octreotide treatment were limited to higher weight gain (days 16 and 23 PI) and decreased food intake (day 23 PI) compared with uninfected-untreated rats.

CONCLUSIONS & INFERENCES

Data confirms the relevance of the present rat model to postinfectious IBS studies and prompt further investigation of somatostatin-dependent regulatory interactions in cryptosporidiosis.

Intensive exploitation of a karst aquifer leads to Cryptosporidium water supply contamination

Groundwater from karst aquifers is an important source of drinking water worldwide. Outbreaks of cryptosporidiosis linked to surface water and treated public water are regularly reported. Cryptosporidium oocysts are resistant to conventional drinking water disinfectants and are a major concern for the water industry. Here, we examined conditions associated with oocyst transport along a karstic hydrosystem, and the impact of intensive exploitation on Cryptosporidium oocyst contamination of the water supply. We studied a well-characterized karstic hydrosystem composed of a sinkhole, a spring and a wellbore. Thirty-six surface water and groundwater samples were analyzed for suspended particulate matter, turbidity, electrical conductivity, and Cryptosporidium and Giardia (oo)cyst concentrations. (Oo)cysts were identified and counted by means of solid-phase cytometry (ChemScan RDI(®)), a highly sensitive method. Cryptosporidium oocysts were detected in 78% of both surface water and groundwater samples, while Giardia cysts were found in respectively 22% and 8% of surface water and groundwater samples. Mean Cryptosporidium oocyst concentrations were 29, 13 and 4/100 L at the sinkhole, spring and wellbore, respectively. Cryptosporidium oocysts were transported from the sinkhole to the spring and the wellbore, with respective release rates of 45% and 14%, suggesting that oocysts are subject to storage and remobilization in karst conduits. Principal components analysis showed that Cryptosporidium oocyst concentrations depended on variations in hydrological forcing factors. All water samples collected during intensive exploitation contained oocysts. Control of Cryptosporidium oocyst contamination during intensive exploitation is therefore necessary to ensure drinking water quality.

Ultra low κ PECVD Porogen Approach: Matrix Precursors Comparison and Porogen Removal Treatment Study

The introduction of new dielectrics into silicon chip interconnection technology is necessary to increase electrical performance. Sub-65nm technologies need κ values below 2.5 and the main way to reduce the dielectric constant is to introduce porosity. This work reports results concerning a two steps PECVD porogen approach to perform Ultra Low κ (κ <2.5). The first step is an hybrid material deposition: i.e. an a-SiOC:H matrix containing organic sacrificial inclusions (porogen phase). In the second step, the porogen is removed by a suitable curing to generate porosity. Two siloxane precursors (decamethylcyclopentasiloxane and diethoxymethylsilane) were evaluated as matrix precursors. Their influences, as well as O2 addition in plasma gas feed, in terms of cross-linking and incorporation were evaluated by FTIR analysis. Thermal anneal and UV treatment (thermally assisted) were evaluated as a curing second step. It allows to better understand this critical step which combines porogen removal and material cross-linking. By optimizing deposition and curing parameters, κ value lower than 2.4 were obtained.

Geosmithia argillacea: an emerging pathogen in patients with cystic fibrosis

We report eight cases of airway colonization by Geosmithia argillacea in patients with cystic fibrosis. This filamentous fungus, resembling members of the genera Penicillium and Paecilomyces, was identified by molecular analysis. All patients carried a mutation on each CFTR (cystic fibrosis transmembrane conductance regulator) allele, with at least one copy of the F508del mutation. The first isolation of this fungus occurred from F508del-homozygous patients at a younger age than in F508del-heterozygous patients. Before recovery of G. argillacea, all patients were treated with itraconazole; two of them had also received voriconazole for an Aspergillus fumigatus infection. However, antifungal susceptibility patterns showed high MICs of voriconazole for all isolates, and high MICs of amphotericin B and itraconazole for the majority of them, but mostly low minimum effective concentrations (MECs) of caspofungin. The appearance and persistence of G. argillacea in the airways were not associated with exacerbation of the disease. However, the clinical implications of G. argillacea, particularly in immunocompromised patients, remain a concern, particularly given recent observations suggesting that this fungus may also cause disseminated infections.

Evaluation of water treatment plant UV reactor efficiency against Cryptosporidium parvum oocyst infectivity in immunocompetent suckling mice

AIM

To assess the efficiency of a medium-pressure UV reactor under full-scale water treatment plant (WTP) conditions on the infectivity of Cryptosporidium parvum oocysts in an Naval Medical Research Institute (NMRI) suckling mice infectivity model.

METHODS AND RESULTS

Six/seven-day-old mice were administered orally 2-10x10(4)Cryptosporidium parvum oocysts. Compared with nonirradiated oocysts, 40 mJ cm(-2) UV irradiation of ingested oocysts resulted 7 days later in a 3.4-4.0 log10 reduction in the counts of small intestine oocysts, using a fluorescent flow cytometry assay.

CONCLUSION

Present data extend to industrial conditions previous observations of the efficiency of UV irradiation against Cryptosporidium parvum oocyst in vivo development.

SIGNIFICANCE AND IMPACT OF THE STUDY

Present results suggest that in WTP conditions, a medium-pressure UV reactor is efficient in reducing the infectivity of Cryptosporidium parvum oocysts, one of the most resistant micro-organisms present in environmental waters.

In vitro efficacy of nitro- and halogeno-thiazolide/thiadiazolide derivatives against Sarcocystis neurona

Sarcocystis neurona is an obligate intracellular parasite that causes equine protozoal myeloencephalitis (EPM). The aim of this work was to document inhibitory activities of nitazoxanide (NTZ, [2-acetolyloxy-N-(5-nitro 2-thiazolyl) benzamide]) and new thiazolides/thiadiazolides on S. neurona in vitro development, and investigate their structure-activity relationships. S. neurona was grown in bovine turbinate cell cultures. At concentrations varying from 1.0 to 5.0mg/L, nitazoxanide and 21 of 32 second generation thiazolide/thiadiazolide agents exerted a > or =95% maximum inhibition on S. neurona development. Most active agents were either NO(2) or halogen substituted in position 5 of their thiazole moiety. In contrast, other 5-substitutions such as hydrogen, methyl, SO(2)CH(3), and CH(3) negatively impacted activity. Compared with derivatives with an acetylated benzene moiety, deacetylated compounds which most probably represent primary metabolites exhibited similar inhibitory activities. Present data provide the first evidence of in vitro inhibitory activities of nitazoxanide and new thiazolides/thiadiazolides on S. neurona development. Active halogeno-thiazolide/thiadiazolides may provide a valuable nitro-free alternative to nitazoxanide for EPM treatment depending on further evaluation of their in vivo activities.