[Show abstract][Hide abstract] ABSTRACT: Background
Penicillium species are among the most common fungi present in the environment and are usually considered non-pathogenic to humans. However, in immunocompromised hosts they can be virulent pathogens and can cause death. Penicillium digitatum is a plant pathogen that commonly causes a postharvest fungal disease of citrus called green mould; it very rarely causes systemic mycosis in humans. Here, we report a case of fatal pneumonia due to P. digitatum infection, as confirmed by repeated examination of cultured sputum.
A cavity was found in the left upper lung on routine chest X-ray in a 78-year-old undernourished male who had been diagnosed at age 66 with bronchial asthma and pulmonary emphysema. No increased sputum production was present. The presence of antigen-specific precipitating antibodies to Aspergillus flavus and P. digitatum was confirmed in the patient’s serum and also later pleural fluid by using Ouchterlony double immunodiffusion testing with A. flavus and P. digitatum antigens. The patient was treated over a period of months with itraconazole, micafungin, voriconazole, amphotericin B, and antibacterials. However, the cavity enlarged, the pleural effusion increased, and the patient began producing purulent sputum. He died from progressive renal failure. From sputum culture only one fungus was isolated repeatedly on potato-dextrose agar in large quantities. This fungus was confirmed to be P. digitatum by molecular identification. Partial sequences of the beta-tubulin gene were determined by using the primers Bt2a and Bt2b for PCR amplification and sequencing and underwent a BLAST search at the National Centre for Biotechnology Information, these results confirmed that the isolated fungus was P. digitatum.
To our knowledge, this is the first report of pulmonary infection with P. digitatum. Our patient had pulmonary emphysema and was elderly, and undernourished. These factors might have facilitated the infection. In his case, antimycotics were ineffective in treating the lung involvement. Although human infection with P. digitatum is considered rare, it appears that this organism can be very virulent and resistant to antimycotics.
BMC Pulmonary Medicine 03/2013; 13(1):16. DOI:10.1186/1471-2466-13-16 · 2.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The National Food Surveillance System in Japan was formed in 1998 to monitor the contamination of retail foods with bacterial pathogens. Approximately 2000-3000 samples were tested annually, and the data from food categories that had more than 400 samples collected during 1998-2008 were analysed. With regard to meat, the frequency of positive samples for Salmonella in chicken for raw consumption and ground chicken was 12.7% and 33.5%, respectively. Moreover, Shiga toxin-producing Escherichia coli (STEC) O157 was found in ground meat, organ meat and processed meat, although at a low frequency (0.1%). The prevalence of Campylobacter jejuni/coli was 13.3% and 20.9% in chicken for raw consumption and ground chicken, respectively. In vegetables and fruit, Salmonella was detected in cucumber, lettuce, sprout and tomato samples at a frequency of around 0.1-0.2%. With regard to seafood, Salmonella was found in 0.5% of oysters for raw consumption. Seafood was not contaminated with STEC O157 or Shigella. Serotype Infantis was the most frequently detected serotype of Salmonella in seafood, followed by the serotypes Typhimurium, Schwarzengrund and Manhattan. In ground chicken, 72.2% of the strains were identified as the serotype Infantis. E. coli, as an indicator of food hygiene, was detected in all food categories. The results show the prevalence of the above-mentioned pathogens in the retail food supplied in Japan; further, they indicate that consumption of raw food carries the risk of contracting food-borne infections.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment 12/2012; 30(8). DOI:10.1080/19440049.2012.745097 · 2.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To establish rapid methods to detect Shiga toxin (Stx)-producing Escherichia coli (STEC) in ground beef samples by using an immunochromatography kit, results of 8-h enrichment in various types of broth with shaking were compared. In pure culture, Stx was detected in the culture of trypticase soy broth (TSB) at 42°C and modified EC broth (mEC) at 36°C from all or most serogroups of O26, O111, O128, O157 and OUT. Ground beef samples inoculated with each serogroup were enriched in TSB at 42°C, mEC at 36°C and mEC with novobiocin (NmEC) at 42°C. Although all conditions led to the successful recovery of each serogroup by the plating method, enrichment in NmEC was relatively superior to the other conditions in the detection of Stx by an immunochromatography kit. These results indicated that the growth of STEC and the release of Stx from cells were different in pure cultures and in culture with ground beef. In addition, polymyxin B treatment for 10 min at 37°C and homogenizing with glass beads enhanced the detection of Stx. From the results, it was suggested that an immunochromatography kit in a combination with enrichment in NmEC at 42°C for 8 h, and treatment with polymyxin B or homogenizing would be a rapid method to detect STEC contamination in ground beef.
[Show abstract][Hide abstract] ABSTRACT: In addition to the crew, microbes also find their way aboard the International Space Station (ISS). Therefore, microbial monitoring is necessary for the health and safety of the crew and for general maintenance of the facilities of this station. Samples were collected from three sites in the Japanese experimental module KIBO on the ISS (air diffuser, handrail, and surfaces) for analysis of fungal biota approximately 1 year after this module had docked with the ISS. Samples taken from KIBO before launch and from our laboratory were used as controls. In the case of KIBO, both microbe detection sheet (MDS) and swab culture tests of orbital samples were negative. The MDS were also examined by field emission-scanning electron microscopy; no microbial structures were detected. However, fungal DNAs were detected by real-time PCR and analyzed by the clone library method; Alternaria sp. and Malassezia spp. were the dominant species before launch and in space, respectively. The dominant species found in specimens from the air conditioner diffuser, lab bench, door push panel, and facility surfaces on our laboratory (ground controls) were Inonotus sp., Cladosporium sp., Malassezia spp., and Pezicula sp., respectively. The fungi in the KIBO were probably derived from contamination due to humans, while those in our laboratory came from the environment (e.g., the soil). In conclusion, the cleanliness in KIBO was equivalent to that in a clean room environment on the ground.
Microbiology and Immunology 09/2011; 55(12):823-9. DOI:10.1111/j.1348-0421.2011.00386.x · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A comprehensive and quantitative analysis of the mycoflora on the surface of commercial fruit was performed. Nine kinds of fruits grown in Japan were tested. Overall fungal counts on the fruits ranged from 3.1 to 6.5 log CFU/g. The mean percentages of the total yeast counts were higher than those of molds in samples of apples, Japanese pears, and strawberries, ranging from 58.5 to 67.0%, and were lower than those of molds in samples of the other six fruits, ranging from 9.8 to 48.3%. Cladosporium was the most frequent fungus and was found in samples of all nine types of fruits, followed by Penicillium found in eight types of fruits. The fungi with the highest total counts in samples of the various fruits were Acremonium in cantaloupe melons (47.6% of the total fungal count), Aspergillus in grapes (32.2%), Aureobasidium in apples (21.3%), blueberries (63.6%), and peaches (33.6%), Cladosporium in strawberries (38.4%), Cryptococcus in Japanese pears (37.6%), Penicillium in mandarins (22.3%), and Sporobolomyces in lemons (26.9%). These results demonstrated that the mycoflora on the surfaces of these fruits mainly consists of common pre- and postharvest inhabitants of the plants or in the environment; fungi that produce mycotoxins or cause market diseases were not prominent in the mycoflora of healthy fruits. These findings suggest fruits should be handled carefully with consideration given to fungal contaminants, including nonpathogenic fungi, to control the quality of fruits and processed fruit products.
[Show abstract][Hide abstract] ABSTRACT: Targeted gene disruption experiments in Trichophyton mentagrophytes are impeded by the dominant of repair of DNA double strand breaks through a nonhomologous end joining pathway (NHEJ). Inactivation of human DNA ligase IV homologs, which is involved in the final step of the NHEJ pathway, has been shown to enhance homologous recombination (HR) frequency in filamentous fungi. To improve the frequency of HR in T. mentagrophytes, the lig4 homolog (TmLIG4) was disrupted. T. mentagrophytes lacking TmLIG4 showed no discernable phenotypic differences when compared to wild-type controls. Both mutant and parent strains had almost identical growth ability, sporulation rate and sensitivity to DNA damaging agents. When four different loci were disrupted in the TMLIG4-deficient mutant, HR frequencies reached as high as 93% depending on the locus, whereas they ranged from 0%-40% in the wild-type. These results suggest that studies in strains lacking TmLIG4 would help to improve our understanding of dermatophytosis by facilitating the genetic manipulation of dermatophytes.
Microbiology and Immunology 01/2011; 55(1):34-43. DOI:10.1111/j.1348-0421.2010.00283.x · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Beef organ meat, such as liver, and beef are major food sources contaminated with Escherichia coli O157. This study investigated the detection method of E. coli O157 in beef liver and carcass. In an experiment with beef liver inoculated with E. coli O157, the direct plating method, plating after the immunomagnetic separation (IMS) method, and Shiga toxin (Stx)-producing E. coli detection and E. coli O157 detection loop-mediated isothermal amplification (LAMP) assays were compared for the detection of Stx-producing E. coli O157. Fifty percent and 45% of samples were positive by Stx-producing E. coli detection LAMP assay and E. coli O157 detection LAMP assay, respectively. Thirty-five percent and 10% of samples were positive by the IMS method and direct plating method, respectively. In an examination of beef swab samples, contamination frequencies with E. coli O157 were analyzed by LAMP assays and the IMS method. E. coli O157 was detected in 12 of 230 samples (5.2%). There was no sample positive for E. coli O157 isolation but negative for LAMP assays for Stx gene and O157 antigen gene. Four samples (1.7%) were positive by both LAMP assays but negative by the IMS method. The result that there was no sample positive for the O157 antigen gene, but not the Stx gene, indicated that the IMS method failed to detect E. coli O157. Twenty-nine samples (12.6%) were positive for the Stx gene but not the O157 antigen gene. The results indicated that screening of Stx gene and O157 antigen gene by LAMP assays is effective in saving time and effort to isolate E. coli O157 by the IMS method because the LAMP assay is more sensitive. This suggested that samples positive for Stx gene and O157 antigen gene should be examined by the IMS method to isolate E. coli O157.
[Show abstract][Hide abstract] ABSTRACT: Intake of a small dose of foodborne pathogens can cause infection. In this study, an estimation of the infectious dose of the pathogens was obtained by conducting microbiological risk assessments. The contamination levels of foodborne pathogens were analysed in 17 outbreaks of Salmonella, Escherichia coli O157, enterotoxigenic E. coli, Vibrio parahaemolyticus, and Campylobacter jejuni occurring in Japan between 2004 and 2006. The infectious dose was estimated in 14 of the 17 outbreaks utilizing existing data. In three outbreaks of Salmonella infection in which the infection rate was 89-100%, the dose of the ingested pathogens was estimated to be 259,000-14,000,000,000 c.f.u. In other outbreaks of Salmonella infection, the infection rate and dose of the ingested pathogens were 10-66·4% and 81-1560 c.f.u. or most probable number (MPN), respectively. The ingested Salmonella dose is likely to be related to the infection rate; however, storage conditions should be taken into account when making this determination. In an outbreak of E. coli O157 infection, the infection rate and ingestion dose were 100% and 2 to <9 c.f.u., respectively, while in an outbreak of enterotoxigenic E. coli infection, they were 93% and 25-1000 c.f.u., respectively. Finally, in an outbreak of C. jejuni infection, the infection rate and ingestion dose were 37·5% and 360 MPN, respectively. These results will be particularly valuable for risk assessment.
Epidemiology and Infection 12/2010; 139(10):1505-10. DOI:10.1017/S095026881000292X · 2.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, enumeration methods for fungi in foods were evaluated using fruits that are often contaminated by fungi in the field and rot because of fungal contaminants. As the test methods, we used the standard most probable number (MPN) method with liquid medium in test tubes, which is traditionally used as the enumeration method for bacteria, and the plate-MPN method with agar plate media, in addition to the surface plating method as the traditional enumeration method for fungi. We tested 27 samples of 9 commercial domestic fruits using their surface skin. The results indicated that the standard MPN method showed slow recovery of fungi in test tubes and lower counts than the surface plating method and the plate-MPN method in almost all samples. The fungal count on the 4th d of incubation was approximately the same as on the 10th d by the surface plating method or the plate-MPN method, indicating no significant differences between the fungal counts by these 2 methods. This result indicated that the plate-MPN method had a number agreement with the traditional enumeration method. Moreover, the plate-MPN method has a little laborious without counting colonies, because fungal counts are estimated based on the number of plates with growing colonies. These advantages demonstrated that the plate-MPN method is a comparatively superior and rapid method for enumeration of fungi.
[Show abstract][Hide abstract] ABSTRACT: In recent years, bottled mineral water has undergone inactivation by methods other than the traditional heat treatment during the production process; there are fewer reports of the effectiveness of these inactivation methods on yeasts and molds in mineral water than on bacteria and protozoan oocysts. In this study, we evaluated the effects of UV irradiation and ozone treatment compared with heat treatment at 85 degrees C on yeast cells and mold spores inoculated into mineral water. A 5-log reduction occurred at a UV radiation dose of 31,433 microJ/cm2 for Saccharomyces cerevisiae and at 588,285 microJ/cm2 for Penicillium pinophilum. The treatment time for 5-log reduction estimated for UV irradiation was about 0.6 min for S. cerevisiae and about 10.7 min for P. pinophilum; at an ozone concentration of 0.1 ppm, it was 1.75 min for S. cerevisiae and 2.70 min for P. pinophilum, and at a concentration of 0.6 ppm, it was 0.32 min for S. cerevisiae and 0.57 min for P. pinophilum. Comparison of the inactivation effects among the three methods showed that UV irradiation and ozone treatment were less effective than heat treatment at 85 degrees C. Thus, when UV irradiation and ozone treatment are used for inactivation of mineral water, it seems that they need to be combined with heat treatment to achieve a definite effect. Yeast cells are more sensitive to all three inactivation methods than are mold spores, and the sensitivity of yeast cells and mold spores to these inactivation methods may vary among genera.
Journal of food protection 08/2010; 73(8):1537-42. · 1.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dermatophytes are filamentous fungi that colonize the keratinized layer of human and animal skin. The availability of several selectable markers for dermatophyte gene manipulation would provide important tools to understand the genetic properties of this fungal group. In this study, we report the nourseothricin resistance gene nat1 that confers resistance to the aminoglycoside antibiotic nourseothricin as a dominant marker in Trichophyton mentagrophytes. The NAT cassette was introduced into T. mentagrophytes by the Agrobacterium tumefaciens-mediated transformation (ATMA) method. Transformation occurred at a frequency of 78 transformants per 1 x 10(7) cells. Molecular analysis showed integration of the NAT cassette into the genomic DNA of T. mentagrophytes. This study presents the nourseothricin resistance gene nat1 as a useful selectable marker for selection of T. mentagrophytes.
Medical mycology: official publication of the International Society for Human and Animal Mycology 11/2009; 48(4):665-8. DOI:10.3109/13693780903330555 · 2.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: : The aim of this study is to investigate relationships between fungal colonization in the house and IgE sensitization to fungi, and to clarify the effects of house care in relation to fungi.
: We measured levels of fungi in the houses of 52 allergic children. Of these, 32 children displayed detectable levels of IgE (≥0.35 UA/ml) to a combination of fungi (positive group). The remaining 20 children were not sensitized to fungi (negative group). Each fungus-specific IgE level was also measured in sera of the positive group, and a questionnaire-based survey was conducted for daily lifestyles.
: Cladosporium was the most prevalent in the houses. From the 32 sera of the positive group, specific IgE levels ≥0.70 UA/ml were most frequently detected in 21 sera for Alternaria. Children in whose houses Alternaria was found displayed higher levels of Alternaria-IgE than those in whose houses where Alternaria was not found. In addition, Alternaria-IgE level was lower for children using an air purifier than for children who were not. Windows were more frequently opened for ventilation in negative-group houses than in positive-group houses.
: The existence of Alternaria might strongly induce IgE sensitization for Alternaria. Using an air purifier and frequently opening windows may minimize fungal sensitization of allergic children.
World Allergy Organization Journal 09/2009; 2(9):208-12. DOI:10.1097/WOX.0b013e3181ba7daf
[Show abstract][Hide abstract] ABSTRACT: Onychomycosis is a fungal infection of fingernails or toenails caused by several species of fungi and yeasts. A Japanese monkey, Macaca fuscata, displayed severe onychomycosis in his 4 limbs. Diagnosis and etiological agent identification were performed by conventional and DNA-mediated methods. The accumulated findings of this case revealed Trichosporon montevideense, which has long been considered to be a nonpathogenic yeast. Here, we present the first report of an involvement of T. montevideense in an onychomycosis case.
Journal of Veterinary Medical Science 08/2009; 71(7):983-6. DOI:10.1292/jvms.71.983 · 0.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Survival of Salmonella in black tiger shrimps during frozen storage was investigated following our previous study on Salmonella contamination in frozen shrimps imported into Japan. Salmonella (S.) Weltevreden and S. Senftenberg were inoculated onto the surface and inside of black tiger shrimps without the shell. After storage at -10 degrees C, -20 degrees C and -30 degrees C for 12 weeks, the Salmonella population decreased in all cases; the decrease was smallest at the lowest temperature. Viability of Salmonella inoculated onto the surface of the shrimp was greater than that inside the shrimp. In addition, viability of S. Senftenberg was greater than that of S. Weltevreden. These results suggest that hygienic handling during thawing of shrimps is important from the viewpoint of Salmonella contamination.
Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 05/2009; 50(2):85-8. DOI:10.3358/shokueishi.50.85 · 0.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Direct colony polymerase chain reaction (DCPCR) is a useful molecular biological technique for application in the field of mycology. In this study, all of the 63 fungal strains examined, including those of the genera Candida and Aspergillus, were amenable to DNA amplification using an Ampdirect(R) Plus kit, which allows direct PCR amplification with no requirement for DNA extraction, following 1 h of rapid fungal lysis. Moreover, we compared DCPCR of 35 strains, representing 20 species, using Ampdirect PCR and standard PCR with no lysis buffer. Thirty-four of these strains (97.14%) yielded positive results on Ampdirect PCR, while only 11 (including Aspergillus fumigatus TIMM1776) of the 35 strains (31.43%) showed PCR products when standard PCR reagents were used. Ampdirect DCPCR was also applicable to DNA amplification for spore and hyphal cells. This approach reduces DNA template preparation time before PCR from fungal colonies, and also reduces the cost of PCR.
Japanese journal of infectious diseases 04/2009; 62(2):164-7. · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aerobic bacteria counts and contamination with Salmonella were investigated in a total of 1,327 samples of commercial liquid egg in 1992-2002. Salmonella was isolated from 8.1% of the samples, and Salmonella contamination was found in 1.7% of even the pasteurized liquid egg samples. The major Salmonella serotype was Enteritidis from more than 50% of the contaminated liquid egg samples. In addition, the aerobic bacteria counts in Salmonella-positive liquid eggs were significantly higher than those of Salmonella-negative samples. However, Salmonella was detected in liquid egg in which the aerobic bacteria counts were in the range of 10(2) to 10(6) cfu/g. Furthermore, foodborne outbreaks of Salmonella infections associated with liquid egg were analyzed. Liquid eggs should be carefully treated to avoid the possibility of Salmonella contamination. Adequate supply of pasteurized liquid eggs and controls to prevent re-contamination are needed.
Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 03/2009; 50(1):34-40. DOI:10.3358/shokueishi.50.34 · 0.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Nivalenol (NIV) is considered to be an important trichothecene mycotoxin produced by Fusarium species because of its frequent contamination in wheat and barley worldwide. The present study examined the subchronic toxicity of NIV in male and female F344 rats fed diets containing 0, 6.25, 25 and 100 mg kg(-1) of the toxin for 90 days. During the experimental period there was a decrease in the white blood cell count at 100 mg kg(-1) in males and at > or =6.25 mg kg(-1) in females. Histopathologically, treatment-related changes were observed in the haematopoietic and immune systems in both sexes and in the female reproductive system at 100 mg kg(-1). Flow cytometric analysis of splenic cells revealed an elevation in the ratio of helper/cytotoxic T-lymphocytes at 100 mg kg(-1). In summary, NIV targets the female reproductive system as well as haematopoietic and immune systems in rats fed NIV for 90 days. Based on a significant decrease in white blood cells in female rats relative to controls, the lowest observable effect level was calculated as 0.4 mg kg(-1) body weight day(-1).
Food Additives & Contaminants: Part A 09/2008; 25(9):1118-27. DOI:10.1080/02652030802093892 · 2.34 Impact Factor