6例由假残托鹅膏引起的中毒病例临床调查及毒物鉴定研究

目的 调查2021年4月浙江省丽水市发生的一起误食野生蘑菇引起神经精神型中毒事件,鉴定毒蘑菇种类,了解中毒症状和救治措施。方法 开展中毒病例的流行病学调查、临床救治分析,毒蘑菇样本现场采集并结合形态学与分子生物学方法鉴定物种。结果 6例患者食用了自己采集并煮汤的蘑菇,于食用后30 min～2 h出现中毒症状,轻症患者恶心呕吐、头晕,重症患者有意识模糊、四肢不自主抽动等症状。轻症患者经过支持性治疗当天痊愈出院,重症患者经过住院治疗顺利恢复。毒蘑菇样本经过形态学结合分子生物学方法鉴定为假残托鹅膏（Amanita pseudosychnopyramis）。结论 该起中毒事件是一起由假残托鹅膏导致的食物中毒事件,国内外文献未见报道。     

贵州省一起灰花纹鹅膏中毒事件调查

目的 调查分析贵州省毕节市发生的一起灰花纹鹅膏中毒事件，为贵州省毒蘑菇中毒的诊断、调查、检测鉴定和防控提供数据支持。方法 采用流行病学调查方法分析该起事件流行病学特征，采用分子生物学方法对可疑野生蘑菇进行鉴定，采用超高效液相色谱-串联质谱法进行毒素检测。结果 该事件为食用自采野蘑菇共导致4人中毒，其中3人死亡。经流行病学调查和实验室检测，确定毒蘑菇为灰花纹鹅膏（Amanita fuliginea），α-鹅膏毒肽、β-鹅膏毒肽和二羟鬼笔毒肽毒素被检出。结论 该起毒蘑菇中毒由村民误采误食灰花纹鹅膏引起，开展针对性的健康教育对毒蘑菇中毒的预防控制具有重要意义。     

梅州市一起致命鹅膏中毒事件的调查与分析

目的 调查2022年广东省梅州市发生的一起毒蘑菇中毒事件，为毒蘑菇中毒的防控提供科学依据。方法 对中毒原因开展流行病学调查，对可疑毒蘑菇样品进行鉴定，同时测定毒蘑菇样品和患者血液与尿液中的毒素。结果 本次毒蘑菇中毒事件4人均出现中毒症状，经治疗均治愈出院。涉事蘑菇样品经鉴定为致命鹅膏（Amanita exitialis）。剩余毒蘑菇汤、已煮毒蘑菇子实体、未煮毒蘑菇子实体残余组织和事发地采集的毒蘑菇中均检出α-鹅膏毒肽；患者血液和尿样样本中均未检出α-鹅膏毒肽。结论 本次事件是因误食致命鹅膏引起的中毒事件，当地村民食品安全防范意识薄弱，需加强对野生蘑菇知识的普及，建立毒蘑菇中毒快速检测技术体系，减少毒蘑菇中毒和死亡事件的发生。     

一起误食光硬皮马勃中毒事件调查

目的 对2019年9月4日发生在云南省楚雄彝族自治州的一起误食光硬皮马勃中毒事件进行调查分析,明确中毒原因,总结中毒特点及救治方法,为该蘑菇中毒事件的处置提供借鉴。方法 收集中毒病例资料、进行流行病学调查、对蘑菇样品进行形态学和分子生物学鉴定。结果 2例患者各进食了约50 g购买于市场的马勃后,出现了腹痛、恶心、呕吐、腹泻及低血压的症状,潜伏期0.5～1 h,经过对症治疗后好转出院。蘑菇标本经形态学和分子生物学鉴定为光硬皮马勃。结论 此次事件是因误食光硬皮马勃引起的急性中毒事件。光硬皮马勃与可食用的云南硬皮马勃外形相似,常因误食而中毒。鉴于很多毒蘑菇与一些食用菌形态上极为相似而导致误采误食,建议不要随意采食野生蘑菇。     

江西省首起误食残托鹅膏有环变种毒蘑菇中毒事件调查与鉴定

目的 调查江西省2019年5月一起误食有毒蘑菇引起的中毒事件,并鉴定引起中毒的有毒蘑菇种类。方法 收集中毒事件的流行病学相关资料进行初步判断,对收集的蘑菇样品进行形态学和分子生物学鉴定。结果 流行病学调查发现患者均食用了自行采摘并煮汤的蘑菇,食量不等,平均潜伏期为2.5 h,出现头晕、恶心、呕吐、四肢麻木等症状,经形态学、分子生物学比对鉴定为残托鹅膏有环变种。结论 本事件为江西省报道的首起因误食残托鹅膏有环变种引起的毒蘑菇中毒事件,结合流行病学、形态学、分子生物学等方法可以鉴定引起毒蘑菇事件的蘑菇种类,提示江西省毒蘑菇中毒形势依然严峻,相关部门应加强防控。     

江西省铅山县一起蘑菇中毒事件的调查与鉴定

目的调查江西省铅山县一起蘑菇中毒事件并对引起中毒的毒蘑菇进行鉴定。方法收集事件病例资料,开展流行病学调查,对蘑菇样品进行外观形态学、分子生物学鉴定。结果流行病学调查结果显示患者均食用了自行采摘的蘑菇,潜伏期约为4 h,出现呕吐、胃肠道不适等中毒症状,给予补液、激素、保肝等护胃解毒支持疗法进行治疗,3 d后全部痊愈出院。分子生物学方法鉴定为疑似大青褶伞。结论此次事件因误食可疑大青褶伞野生蘑菇而引起急性中毒,结合流行病学、分子生物学等方法可以较好地鉴定毒蘑菇种类。     

武汉市一起毒蘑菇中毒事件现场调查和鉴定

目的调查分析武汉市一起毒蘑菇中毒事件的处置过程,鉴定引起中毒的毒蘑菇种类,为做好此类中毒事件的处置提供借鉴。方法收集事件病例资料,开展流行病学调查,对蘑菇样品进行形态学和分子生物学鉴定并对中毒事件进行分析。结果患者均食用自行采摘并炒制的蘑菇,食量不等。病例早期临床表现以胃肠道症状为主,后期以肝、肾和凝血功能损伤为主。经形态学和分子生物学鉴定为裂皮鹅膏菌。结论本次事件是因误食裂皮鹅膏菌引起的急性中毒。结合流行病学特点和患者临床表现,证实了通过形态学及分子生物学方法对裂皮鹅膏菌的物种鉴定具有适用性。     

应用rDNA-内转录间隔区分子条形码技术调查福建省亚稀褶黑菇中毒事件

目的调查福建省南平地区3个市县的3起野生菌食物中毒事件,为今后野生菌中毒调查和处置积累经验,减少中毒事件的发生。方法通过查阅中毒患者的临床救治资料,前往中毒事件发生地采集引起中毒的可疑蘑菇样品,并采用rDNA-内转录间隔区(rDNA-ITS)分子条形码鉴定技术进行种属鉴别。结果中毒流行病学特征、中毒患者临床特征、生化指标变化和分子生物学鉴定的结果表明,2017年8月的2起食物中毒事件均由亚稀褶黑菇(Russula subnigricans Hongo)导致;根据中毒患者临床特征,另一起中毒事件亦被推断为由亚稀褶黑菇引起;3起中毒事件中,蘑菇食用者为21人,发病17人,罹患率为81.0%,其中3人死亡,病死率为17.6%(3/17)。结论首次在福建省通过分子生物学手段鉴别出由亚稀褶黑菇引起的食物中毒事件;亚稀褶黑菇广泛分布于福建山区,易被误采误食而引起中毒事件,且病死率高。     

浙江省长兴县一起误食毒蘑菇中毒事件调查

目的 调查分析浙江省长兴县一起毒蘑菇中毒事件中毒蘑菇的种类,分析事件发生原因,总结调查处置经验,为中毒患者的救治和中毒的预防提供借鉴。方法 对中毒事件开展现场流行病学调查,对毒蘑菇样品进行形态学鉴定和分子系统学鉴定。结果 本次毒蘑菇中毒事件共发病3人,其中1例重症,2例轻症,罹患率为100%,主要临床表现为恶心、呕吐、腹泻等症状,其中1例经短暂“假愈期”后出现严重横纹肌溶解中毒症状,血清肌酸激酶(CK)最高达318 200 U/L。毒蘑菇样品经形态学及分子系统学鉴定为亚稀褶红菇。结论 本次事件是一起因误食亚稀褶红菇引起的毒蘑菇中毒事件。加强宣传教育,提升民众防范意识,提高医疗机构的诊断救治能力是预防毒蘑菇中毒的关键。     

秦皇岛市一起野生蘑菇中毒事件的调查和确证

目的 调查分析秦皇岛市一起食用野生蘑菇中毒事件,鉴定毒蘑菇种类,总结调查处置经验,提出防控措施,为野生蘑菇中毒患者的救治和预防提供借鉴。方法 运用现场流行病学调查、形态学鉴定和蘑菇毒素检测方法对中毒事件进行综合判断分析。结果 秦皇岛市4名村民食用自采野生蘑菇后全部出现恶心、腹痛、腹泻、多汗、寒颤等症状。在医院接受催吐、洗胃、给予阿托品及其他对症治疗,患者预后良好。经形态学鉴定和毒素检测后判定为一起由食用丝盖伞属蘑菇引起的食物中毒。结论 这是河北省首次报道由丝盖伞属蘑菇引起的中毒事件,中毒原因系受网络误导,食品安全防范意识差导致的误食。因此应加强食品安全宣传教育,提升民众防范意识,预防采食野生蘑菇中毒。     

Arsenic content of some edible mushroom species

The arsenic contents of 162 fruit body samples of 37 common edible mushroom taxa were analyzed. The samples were gathered from different habitats of Hungary (mainly from mountains) between 1984 and 1999. The arsenic content of the samples was measured by the inductively coupled plasma spectrometry method. Very low [lower than 0.05 mg/kg dry matter (DM)] concentrations were found in the samples of 13 taxa, while higher (or very high) contents were quantified in other common taxa (the highest arsenic content was recorded in the fruit body of Laccaria amethysthea at 146.9 mg/kg DM). The species of eight genera (Agaricus, Calvatia, Collybia, Laccaria, Langermannia, Lepista, Lycoperdon, Macrolepiota) belong to the so-called accumulating taxa, and this tendency is evident on all habitats. This arsenic accumulation capability is found in two orders of Basidiomycetes (Agaricales and Gasteromycetales), which is to say this phenomenon occurs in the families Agaricaceae, Tricholomataceae and Gasteromycetaceae. The accumulating taxa found all have a saprotrophic type of nutrition; arsenic accumulation is not detectable in xilophagous or in mycorrhizal species. The consumption of the accumulating species found has only a low toxicological risk for three reasons: the consumed fresh fruit bodies contain about a tenfold lower arsenic level than the dried ones, the majority of arsenic occurs not in poisonous inorganic, but in less dangerous (or not poisonous) organic forms, and the frequency of consumption is low.     

Organization and localization of the dnaA and dnaK gene regions on the multichromosomal genome of Burkholderia multivorans ATCC 17616

The Burkholderia multivorans strain ATCC 17616 carries three circular chromosomes with sizes of 3.4, 2.5, and 0.9 Mb. To reveal the distribution and organization of the genes for fundamental cell functions on the genome of this bacterium, the dnaA and dnaK gene regions of ATCC 17616 were cloned and characterized. The gene organization of the dnaA region was rnpA-rmpH-dnaA-dnaN-gyrB with a single consensus DnaA-binding box (TTATCCACA) between the rmpH and dnaA genes. This intergenic region, however, did not work as an autonomously replicating sequence in ATCC 17616. On the other hand, the gene organization of the dnaK region was grpE-orf1 (gene for thioredoxin homologue)-dnaK-dnaJ-pabB (gene for p-aminobenzoate synthetase component homologue). A putative heat-shock promoter that showed good homology to the sigma32-dependent promoter consensus sequence in Escherichia coli was found upstream of the grpE gene, suggesting that these five genes constitute an operon. In M9 succinate minimal medium the dnaJ mutant grew more slowly than the wild-type strain, indicating that this operon is functional. Pulsed-field gel electrophoresis and Southern blot analyses indicated that both the dnaA and dnaK gene regions exist as single copies on the 3.4 Mb chromosome.     

Contamination with storage fungi of human food from Cameroon

In a mycological study, a total of 95 human food samples were investigated to evaluate the incidence of fungal contamination in Cameroon by conventional identification method and partly confirmed by DNA sequencing. The isolated fungal spp. were further studied to determine their toxigenic potentials. The investigation revealed the predominance of Aspergillus and Penicillium with 96% of samples contaminated with at least one species of these fungi, whereas the incidence of co-contamination of samples was 85%. Aspergillus flavus and Aspergillus parasiticus (Flavi section) were the most predominant species contaminating mainly maize and peanuts. In addition, P. crustosum and P. polonicum were the most common contaminants belonging to the genus Penicillium. On the other hand, A. ochraceus (Circumdati section) registered a low incidence rate of 5%, including other members of the Aspergillus group. Other members of the genera Rhizopus and Alternaria spp. were also registered in the study. A majority of fungal strains of A. ochraceus, A. parasiticus, P. crustosum and P. polonicum isolated were toxigenic, producing the mycotoxins tested for, while none was detected in cultures of A. fumigatus. The high incidence rate of fungi contamination coupled with their potentials in producing mycotoxins gives a strong indication that the samples tested may likely be contaminated with various mycotoxins. There is need for further study to assess the incidence of mycotoxins contamination in similar food samples.     

Microbial profiles of frozen trimmings and silver sides prepared at Indian buffalo meat packing plants

To assess microbiological quality of buffalo meat trimmings (TT = 114) and silver sides (SS = 41), samples were collected from four different Indian meat packing plants. The aim of this study was: (i) to evaluate standard plate count (SPC), psychrotrophic count (PTC), Enterococcus feacalis count (EFC), Staphylococcus aureus count (SAC) and Escherichia coli count (ECC) and the presence of Salmonella spp. and Listeria monocytogenes; and (ii) also to determine vero toxic E. coli (VTEC) by polymerase chain reaction (PCR). TT samples had significantly higher (P < 0.001) SPC, PTC, EFC, and SAC than SS, while across the meat types there was no difference (P > 0.05) in ECC. E. coli was recovered from 32.4% TT and 19.5% SS samples. The prevalence rate of Salmonella spp. and L. monocytogenes in TT was 1.75% and 0.87%, respectively. But no SS sample was found to be positive for any of these two pathogens. VTEC was found in 2.58% of all the tested samples. This finding suggests that TT contain higher microbes but only small numbers of pathogens of latent zoonotic importance. The present study confirmed the importance of maintaining good process hygiene at meat plants for microbiological status of buffalo meat.     

Susceptibility of stored product insects to high concentrations of ozone at different exposure intervals

Ozone is a highly reactive gas with insecticidal activity. Past studies have indicated that ozone technology has potential as a management tool to control insect pests in bulk grain storage facilities. The objective of this study was to determine the efficacy of short periods of exposure to high ozone concentrations to kill all life stages of red flour beetle (Tribolium castaneum (Herbst)) (Coleoptera: Tenebrionidae), and Indianmeal moth (Plodia interpunctella (Hübner)) (Lepidoptera: Pyralidae), adult maize weevil (Sitophilus zeamais (Motsch.)) (Coleoptera: Curculionidae) and adult rice weevil (S. oryzae (L)) (Coleoptera: Curculionidae). Insects were treated with six ozone concentrations between 50 and 1800 ppm. The specific objective was to determine minimal time needed to attain 100% mortality. The most ozone-tolerant stages of T. castaneum were pupae and eggs, which required a treatment of 180 min at 1800 ppm ozone to reach 100% mortality. Eggs of P. interpunctella also required 180 min at 1800 ppm ozone to reach 100% mortality. Ozone treatments of 1800 ppm for 120 min and 1800 ppm for 60 min were required to kill all adult S. zeamais and adult S. oryzae, respectively. The results indicate that high ozone concentrations reduce the treatment times significantly over previously described results. Our results also provide new baseline information about insect tolerance to ozone treatment.     

Effect of Zataria multiflora Boiss. essential oil and nisin on Salmonella typhimurium and Staphylococcus aureus in a food model system and on the bacterial cell membranes

The effects of different concentrations of Zataria multiflora Boiss. essential oil (EO: 0, 5, 15 and 30 μl 100 ml⁻¹) and nisin (N: 0, 0.25 and 0.5 μg ml⁻¹), temperatures (T: 25 and 8 °C), and storage times (up to 21 days) on growth of Salmonella typhimurium and Staphylococcus aureus in a commercial barley soup were evaluated in a factorial design study. The growth of S. typhimurium was significantly (P < 0.05) decreased by EO concentrations and their combinations with N concentrations at 8 °C. For S. aureus, the viable count was significantly (P < 0.05) inhibited by EO and N concentrations and their combinations, incubated at both storage temperatures. The mechanism of the antimicrobial action of EO, N, and their combinations against cell membranes of the tested organisms were also studied by measurement of the release of cell constituents and by the electronic microscopy observations of the cells. The significant increase of the cell constituents’ release of both organisms was observed as a result of treatments with EO and EO in combination with N. Electronic microscopy observations revealed that the cell membranes of S. typhimurium treated by EO and EO in combination with N were significantly damaged, while cells treated with only N looked similar to untreated cells. The electron micrographs of treated cells of S. aureus with EO, N, and their combination also showed important morphological damages and disrupted membranes.     

Formation of cereulide and enterotoxins by Bacillus cereus in fermented African locust beans

Afitin, iru and sonru are three spontaneously fermented African locust bean Benin condiments. The fermentation processes are exothermic, with temperatures mostly being above 40 °C. A total of 19 predominant Bacillus cereus isolates from afitin, iru and sonru, were investigated. The enterotoxin genes nhe (A, B, C) were present in all 19 isolates, the hbl (A, C, D) in one (afitin), and the cytK gene in three isolates (afitin). Levels of cytotoxicity to Vero cells and NheA production in BHI-broth was within the range of known diarrheal outbreak strains. Autoclaved cooked African locust beans inoculated with emetic (cereulide producing) B. cereus Ba18H2/RIF supported growth at 25, 30 and 40 °C with highly different maximum cereulide productions of 6 ± 5, 97 ± 3 and 0.04 ± 0.02 μg/g beans, respectively (48 h). For non-autoclaved cooked beans inoculated with 2, 4 and 6 log₁₀B. cereus Ba18H2/RIF spores/g beans, cereulide production was 5 ± 4, 64 ± 8 and 69 ± 34 μg/g beans, respectively at 24 h, while it was 70 ± 43, 92 ± 53 and 99 ± 31 μg/g at 48 h of fermentation at 30 °C. Even though high toxin levels were observed, to date there are no known reports on diarrhea or vomiting due to the consumption or afitin, iru and sonru in Benin, which also according to the present study is likely to be expected from the low levels of cereulide produced at 40 °C.     

Cloning and expression analysis of two catalase genes from Aspergillus oryzae

Fungi contain distinct genes encoding the same class of enzyme that are differentially regulated according to conditions. We cloned two catalase genes, catA and catB, from Aspergillus oryzae. The catA gene predicts a 747-amino-acid polypeptide sharing 81% identity with Aspergillus fumigatus catalase (catA) and 77% with Aspergillus nidulans catalase (catA). The catB gene predicts a 725-amino-acid polypeptide sharing 82% identity with A. fumigatus catalase (catB) and 75% with A. nidulans catalase (catB). However, the catA and catB genes share little homology (41%) with one another, suggesting that each gene belongs to a distinct gene family. Overexpression studies demonstrated that both genes encode a functional catalase. Promoter assays indicated that the catA gene is developmentally regulated as it was preferentially expressed in solid-state cultures undergoing sporulation. However, its expression was not affected by hydrogen peroxide treatment. Conversely, the catB gene was highly expressed under all culture conditions tested, and it was induced by hydrogen peroxide treatment. These results suggest that the catB gene may be mainly used for detoxification of oxidative stress while the catA gene may have another role such as chaperoning proteins in the spore.