Listeria monocytogenes septicemia in a Thoroughbred foal.

Listeria monocytogenes septicemia was diagnosed in a 6-day-old Thoroughbred foal. Primary clinical signs included fever, depression, diarrhea, and respiratory distress. Hematologic abnormalities included leukopenia, neutropenia, degenerative left shift, and hyperfibrinogenemia. Clinical chemistry and blood gas abnormalities included metabolic acidosis, hypoxemia, hypocapnia, hypoglycemia, and hyponatremia. Despite aggressive therapeutic intervention and intensive care, the foal died within 12 hours of admission. A postmortem examination was performed, and the primary gross lesion was bilaterally severe, focally extensive bronchopneumonia. Histopathology revealed severe subacute multifocal suppurative bronchopneumonia with necrotizing vasculitis and intralesional coccobacilli. Cultures of blood collected at admission and immediately prior to death were positive for L. monocytogenes, as were cultures obtained from lung and liver at necropsy. Immunohistochemical examination of formalin-fixed tissues revealed abundant intra- and extracellular L. monocytogenes antigen within the lung and intravascularly in multiple organs.     

Encephalitic listeriosis in two adult llamas (Lama glama): clinical presentations, lesions and immunofluorescence of Listeria monocytogenes in brainstem lesions

Encephalitic listeriosis was diagnosed in 2 adult llamas. Both had a multifocal suppurative encephalitis with mixed lymphocytic and neutrophilic perivascular infiltrates. Listeria monocytogenes was cultured from the brain stem of 1 llama using cold enrichment techniques; the other llama was culture negative. Formalin-fixed and paraffin embedded sections of brainstem lesions from both affected animals were labeled with a fluorescein-conjugated, anti-L. monocytogenes antibody. Using this technique, intralesional L. monocytogenes were identified in both llamas.     

Clinicopathological findings in sheep from Sardinia showing neurological signs of disease

Histopathological and bacteriological examinations were performed on 178 brains from Sardinian sheep which were showing neurological signs. The sheep represented the total number of sheep with neurological syndromes submitted for diagnostic investigations over a three-year period in Sardinia. Scrapie was detected in 57 cases, cerebrocortical necrosis in 25, intoxication by a typical Mediterranean plant (Cistus species) was suspected in 25, coenurosis was detected in 11 cases, Listeria monocytogenes in eight cases and focal symmetrical encephalomalacia in six cases. Non-suppurative inflammatory changes were observed in three of the brains and suppurative changes were noted in two. Lesions restricted to the spinal cord were found in three cases. In the remaining 38 cases there were no significant neuropathological changes.     

单核细胞增多性李氏杆菌人工感染绵羊试验

将人从病羊脑分离纯化的单核细胞增多性李氏杆菌经列脉接种于健康得奴绵羊３只,结果被感染绵羊均表现出与自然感染绵羊相同的临床症状和病理变化,并从脑、心血、淋巴结中回收到了单核细胞增钨生李氏杆菌,从而证明了该分离株单核细胞增多性李氏杆菌具有较强的致病性。     

Listeria monocytogenes and Escherichia coli septicemia and meningoencephalitis in a 7-day-old llama

Listeria monocytogenes and Escherichia coli were isolated from blood collected on presentation and tissues samples taken postmortem. Listeria monocytogenes was isolated from cerebrospinal fluid collected antemortem. The importance of passive transfer of immunity, the subtlety of neurologic signs in early meningitis, and considering blood-CSF penetration in antimicrobial selection are discussed.     

Biliary excretion as possible origin of Listeria monocytogenes in fecal carriers.

The presence of Listeria monocytogenes in feces of animals has been related with ingestion of contaminated foods. In the study reported here, healthy mice inoculated SC with L monocytogenes excreted the organism in their feces, regardless of whether they developed clinical signs of infection. Listeria monocytogenes was isolated simultaneously from liver, feces, and bile of inoculated mice, which strongly suggested that the microorganism reached the gastrointestinal tract by biliary excretion.     

Listeria monocytogenes in horses in Iceland

Twenty isolates of Listeria monocytogenes associated with five confirmed and four suspected incidents of listeriosis in horses in Iceland were characterised by serotyping, pulsed-field gel electrophoresis and ribotyping. Semiquantitative estimates of the numbers of L monocytogenes were made on faeces from horses with clinical signs of listeriosis and on grass silage fed to them. Large numbers of L monocytogenes were often found in the faeces of horses with severe signs of disease. The 20 isolates could be divided into six genotypes, each incident involving only one genotype. One serovar 1/2a genotype was associated with three confirmed incidents of listeriosis in 1991, 1993 and 1997. In one incident, the same genotype was isolated from the organs of a horse with listeriosis and from the spoiled grass silage fed to it.     

Listeriosis in an Arabian foal with combined immunodeficiency.

A 1-month-old Arabian foal with signs of central nervous system disease was found to have combined (B- and T-lymphocyte) immunodeficiency. The foal died in spite of intensive antibiotic therapy. At necropsy, generalized lymphoid hypoplasia and acute necrotizing and granulomatous inflammation of the brain, heart, and adrenal glands were found. In addition, there were spinal meningitis and focal hepatic necrosis. Listeria monocytogenes was isolated on primary culture from the brain.     

李氏杆菌溶血素基因的表达及活性分析

根据LMO溶血素基因hlyA设计引物,PCR扩增hlyA,将扩增产物与pMD18-T连接,重组质粒经酶切鉴定、PCR分析以及确证性测序。将由重组质粒pMD18-hlyA上扩增的缺失信号肽序列的目的片段与表达载体DGEX-4T-1分别酶切连接后,转化BL21细胞。筛选阳性克隆,用IPTG诱导表达,SDS-PAGE和Western blot分析,纯化重组融合蛋白进行溶血试验、小鼠致病力试验和间接ELISA分析。结果表明hlyA基因在大肠杆菌中成功表达分子量82Ku的融合蛋白,能裂解红细胞,且能被LMO阳性血清所识别。一定剂量腹腔注射能将小鼠致死。以此为包被抗原的间接ELISA可以将LMO阴、阳性血清分开。这表明GST-LLO融合蛋白具有良好的生物活性,可用于李氏杆菌病的间接ELISA诊断。     

应用环介导等温扩增技术快速检测单核细胞增生李斯特菌的研究

目的建立环介导等温扩增技术快速检测单核细胞增生李斯特菌。方法根据单核细胞增生李斯特菌(LM)hlyA基因序列中的保守区域,采用在线引物设计软件Primer Explorer4.0进行设计,获得一套特异性的环介导等温扩增(LAMP)引物,对单核细胞增生李斯特菌hlyA基因进行LAMP扩增,并与常规PCR方法进行比较。结果建立的LAMP方法能成功扩增出梯形条带,LAMP检测单核细胞增生李斯特菌纯培养物和人工染菌的灵敏度为5.44×102cfu/mL,而对照PCR检测的灵敏度为5.44×104cfu/mL。对10株细菌进行LAMP扩增,仅单核细胞增生李斯特菌得到阳性结果。从DNA提取到报告结果,耗时仅1h。结论 LAMP检测单核细胞增生李斯特菌灵敏度高,特异性强,耗时短,方法简便,有望发展成为快速检测食品中单核细胞增生李斯特菌的有效手段。     

新疆不同来源单核细胞增生李斯特氏菌血清型的多重PCR鉴定

为鉴定分离自新疆北疆绵羊单核细胞增生李斯特氏菌,本研究采用多重PCR方法,鉴定来自病发地区部分羊场的发病绵羊、健康绵羊、羊舍环境和乌鸦粪分离的30株李斯特氏菌分离株的8株单核细胞增生李斯特氏菌分离株血清型。结果为4株发病绵羊株有3株鉴定为单核细胞增生李斯特氏菌,血清型为1/2a或4b,1株为非单核细胞增生李斯特氏菌;5株健康绵羊株血清型为1/2a;其余来自羊舍水源的3株、乌鸦粪的2株及健康绵羊16株为非单核细胞增生李斯特氏菌,表明来自发病绵羊、健康绵羊及参考菌株LM血清型之间具有相关性。     

Listeria monocytogenes subtypes associated with mortality among fallow deer (Dama dama).

Different subtypes of Listeria monocytogenes were isolated from various animal and environmental samples during an episode of increased mortality on a fallow deer (Dama dama) farm. During a 4-wk period, six fallow deer died, including four does, one fawn, and one adult buck. Prior to death, one of the does had exhibited central nervous system signs characteristic of listeriosis. Postmortem examination of the six deer showed no histologic changes typical of listeriosis, although inflammatory changes were present in several organs. Different subtypes of L. monocytogenes were isolated from brain samples from six deer, from fodder and soil from the deer feeding area, and from faces of some healthy animals on the farm. Listeria monocytogenes, which was frequently isolated in the environment of the farm, was considered the probable major cause of mortality in these fallow deer.     

A case of bovine raw milk contamination with Listeria monocytogenes

ABSTRACT: During routine sampling of bulk raw milk on a dairy farm, the pathogenic bacteria Listeria monocytogenes was found to be a contaminant, at numbers < 100 cfu/ml. A strain with an indistinguishable pulsed-field gel electrophoresis pattern was isolated from the bulk milk two months later. Environmental swabs taken at the dairy environment were negative for the presence of L. monocytogenes, indicating a possible case of excretion of the L. monocytogenes directly into the milk. Milk samples were collected from the individual cows and analysed, resulting in the identification of L. monocytogenes excretion (at 280 cfu/ml) from one of the 4 mammary quarters of one dairy cow out of 180. When the infected cow was isolated from the herd, no L. monocytogenes was detected from the remaining herd. The pulsed-field gel electrophoresis pattern of the strain from the individual cow was indistinguishable from that originally isolated from the bulk milk. The infected cow did not show any clinical signs of disease, nor did the appearance of the milk have any physical abnormalities. Antibiotic treatment of the infected mammary quarter was found to be ineffective. This study shows that there can be risks associated with direct contamination of raw milk with L. monocytogenes.     

An outbreak of listeriosis in cattle in Nigeria.

An outbreak of listeriosis in a herd of cattle associated with still birth, abortion, nervous signs and death is reported. Typical micro abscesses in the brain were not observed on histopathology but a marked purulent meningitis was seen and Listeria monocytogenes was isolated on culture.     

Listeriosis in a cockatiel (Nymphicus hollandicus)

Listeriosis was diagnosed in a 4-yr-old female cockatiel (Nymphicus hollandicus) that died after exhibiting clinical signs that included a fluffed-up appearance, weakness, and loss of weight of several days duration. Grossly, the bird was moderately emaciated, and the liver and spleen were enlarged. Microscopically, there was mild-to-moderate inflammation associated with rod-shaped, gram-positive bacteria in the liver, spleen, kidneys, adrenal glands, bone marrow, and esophagus. Listeria monocytogenes was isolated from the liver, trachea, and intestine. The isolate was identified as type 1 by agglutination with specific antisera, and it further identified as belonging to serovar group 1/2a, 3a by multiplex polymerase chain reaction assay. Listeria monocytogenes also was detected in affected tissues by immunohistochemistry.     

Kinetics of antibody production and clinical profiles of calves experimentally infected with Listeria monocytogenes

Clinical and serum antibody profiles were studied during oral Listeria monocytogenes infection of calves. No clinical signs, except for pyrexia with mild diarrhoea and staggering gait, were observed in the infected calves. Specific antibodies to listeriolysin O (LLO) appeared as early as day 8 of an oral infection and peaked by days 16-32 of infection. Antibodies to LLO were observed to persist over the period of 126 days observed in the study. LLO being a major virulence factor and capable of inducing a humoral response could therefore be used as an antigen for development of an immunoassay for diagnosis of Listeria monocytogenes infections in animals.     

Necrotizing encephalitis of unknown cause in Fennoscandian Arctic foxes (Alopex lagopus).

A neurologic disease affected a colony of endangered Fennoscandian arctic foxes (Alopex lagopus) kept in captivity for breeding purposes. Several outbreaks of disease occurred between 1994 and 2004. The clinical signs included ataxia, indications of anosmia, blindness, and abnormal behavior. The disease was characterized by severe necrotizing encephalitis affecting mostly the cranial cerebrum, basal ganglia, and olfactory bulbs. Investigations to identify the etiology of the disease included testing for several infectious agents known to cause encephalitis in carnivores. Tests for Toxoplasma gondii, Encephalitozoon cuniculi, Neospora caninum, canine distemper virus, rabies, adenovirus type 1, Borna disease virus, and Listeria monocytogenes were negative. The colony was closed, and the cause of the disease remains undetermined.