Numerical taxonomy of gram-negative, nonmotile, nonfermentative bacteria isolated during chilled storage of lamb carcasses.

A numerical taxonomic study using 75 characters was performed with 132 strains of gram-negative, nonmotile, nonfermentative bacteria selected on the basis of lack of motility and Gram reaction among 1,200 cultures isolated during aerobic storage of lamb carcasses. At the 80% similarity level (SSM), eight clusters were formed. Strains in clusters 1 to 6 could be identified as members of the family Moraxellaceae and, more specifically, as members of the Psychrobacter-[Moraxella] phenylpyruvica subgroup. Of these strains, clusters 1 and 2 (88 strains) were identified as [Moraxella] phenylpyruvica and cluster 3 (15 strains) was identified as Psychrobacter immobilis. Clusters 4, 5, and 6 were not identifiable with any species. Clusters 7 and 8 consisted of 14 strains considered nonmotile variants of Pseudomonas fragi. The highest separation indices corresponded to acid production from certain carbohydrates (melibiose, L-arabinose, and cellobiose). Although strains of Psychrobacter-Moraxella clusters were relatively frequently identified at the completion of slaughter, very few cultures were detected on spoiled carcasses. It appears, therefore, that this group of organisms has only low spoilage potential.     

A numerical taxonomic study of Pseudomonas strains from spoiled meat

A numerical taxonomic study using 160 unit characters has been performed on 110 isolates of pseudomonads from aerobically spoiled beef and pork and on 13 named strains from the genus Pseudomonas. Four clusters of meat strains were detected at 87% S. Non-fluorescent strains were contained in two closely related clusters (1 and 2) which were identified with P. fragi. Clusters 3 and 4 contained fluorescent strains which were distinct from P. fluorescens, P. putida and the other named strains examined. An identification scheme based on 11 carbon source tests is presented for the recognition of cluster members.     

Surgical treatment of fungating lesion of foot due to Moraxella phenylpyruvica. Case report

We present a case report of a man who had an abscess-like lesion on his left foot. The lesion discharged pus, enlarged, and became thicker, so that we could not differentiate the real toes from the out-growths. Moraxella phenylpyruvica and Pseudomonas putrefaciens were identified; direct agglutination tests were postive M. phyenylpyruvica. He was given antibiotics and antituberculosis therapy and had topical treatments. The foul odor disappeared with treatment, and the lesions were removed surgically 3 months later. The M. phenylpyruvica finally disappeared after the surgery. The final condition of this patient was markedly improved, although he had some residual scar contracture.     

Amplified Fragment Length Polymorphism Fingerprinting of Pseudomonas Strains from a Poultry Processing Plant

Molecular typing has been used previously to identify and trace dissemination of pathogenic and spoilage bacteria associated with food processing. Amplified fragment length polymorphism (AFLP) is a novel DNA fingerprinting technique which is considered highly reproducible and has high discriminatory power. This technique was used to fingerprint 88 Pseudomonas fluorescens and Pseudomonas putida strains that were previously isolated from plate counts of carcasses at six processing stages and various equipment surfaces and environmental sources of a poultry abattoir. Clustering of the AFLP patterns revealed a high level of diversity among the strains. Six clusters (clusters I through VI) were delineated at an arbitrary Dice coefficient level of 0.65; clusters III (31 strains) and IV (28 strains) were the largest clusters. More than one-half (52.3%) of the strains obtained from carcass samples, which may have represented the resident carcass population, grouped together in cluster III. By contrast, 43.2% of the strains from most of the equipment surfaces and environmental sources grouped together in cluster IV. In most cases, the clusters in which carcass strains from processing stages grouped corresponded to the clusters in which strains from the associated equipment surfaces and/or environmental sources were found. This provided evidence that there was cross-contamination between carcasses and the abattoir environment at the DNA level. The AFLP data also showed that strains were being disseminated from the beginning to the end of the poultry processing operation, since many strains associated with carcasses at the packaging stage were members of the same clusters as strains obtained from carcasses after the defeathering stage.     

大连渤海老虎滩海域沉积物可培养放线菌的多样性

【目的】研究大连渤海老虎滩海域可培养放线菌的多样性。【方法】利用5种不同的培养基分离、培养海洋沉积物中的放线菌,并用16S rRNA基因序列对部分放线菌株进行系统发育分析。【结果】根据菌落表型共分离到1215株放线菌。选择271株具有代表性的菌株进行16S rRNA分析,结果表明,251株(92.26%)属于放线菌门,覆盖11个科,15个属;其余20株属于厚壁门和变形菌门;有7株为潜在的新种。【结论】大连渤海老虎滩海域的沉积物中存在较为丰富的放线菌和新种资源,这些菌株为将来开发新的微生物代谢产物奠定了基础。     

Degradation of fluoranthene, pyrene, benz[a]anthracene and dibenz[a,h]anthracene by Burkholderia cepacia

Microbiological analysis of soils from a polycyclic aromatic hydrocarbon (PAH)-contaminated site resulted in the enrichment of five microbial communities capable of utilizing pyrene as a sole carbon and energy source. Communities 4 and 5 rapidly degraded a number of different PAH compounds. Three pure cultures were isolated from community 5 using a spray plate method with pyrene as the sole carbon source. The cultures were identified as strains of Burkholderia ( Pseudomonas ) cepacia on the basis of biochemical and growth tests. The pure cultures (VUN 10 001, VUN 10 002 and VUN 10 003) were capable of degrading fluorene, phenanthrene and pyrene (100 mg l⁻¹) to undetectable levels within 7–10 d in standard serum bottle cultures. Pyrene degradation was observed at concentrations up to 1000 mg l⁻¹. The three isolates were also able to degrade other PAHs including fluoranthene, benz[ a ]anthracene and dibenz[ a , h ]anthracene as sole carbon and energy sources. Stimulation of dibenz[ a , h ]anthracene and benzo[ a ]pyrene degradation was achieved by the addition of small quantities of phenanthrene to cultures containing these compounds. Substrate utilization tests revealed that these micro-organisms could also grow on n -alkanes, chlorinated- and nitro-aromatic compounds.     

两种培养基对对虾苗池海洋蛭弧菌的分离及其多样性分析

【目的】明确海水(Sw)和聚蛋白胨20(Pp20)两种双层琼脂培养基对海洋蛭弧菌的分离计数效果,了解对虾苗池可培养海洋蛭弧菌多样性。【方法】采用双层平板法,比较Sw和Pp20培养基对2株海洋蛭弧菌和对虾苗池未知海洋蛭弧菌的计数效果。通过宿主范围测试和16S rRNA基因序列分析评估两种培养基分离苗池海洋蛭弧菌的多样性。【结果】宿主菌含量高时,Sw培养基对两株已知海洋蛭弧菌的计数值均显著高于(P0.05)Pp20。Sw和Pp20培养基从同一苗池水样分别分离得到21和22株蛭弧菌。根据宿主裂解范围差异,43株分离物可分为15种裂解模式,其中Sw和Pp20培养基各分离到12和8种。16S rRNA基因序列分析表明,所有分离物都被鉴定为噬菌弧菌属(Bacteriovorax)菌株,并可分为6个类群,Sw和Pp20培养基分别分离到6和4个类群。【结论】Sw培养基在分离计数海洋蛭弧菌及其多样性检测上效果均优于Pp20;对虾苗池可培养海洋蛭弧菌具有较高多样性,并以类群XIII、X及一个潜在新类群为优势种群。     

Redox centers of 4-hydroxybenzoyl-CoA reductase, a member of the xanthine oxidase family of molybdenum-containing enzymes

4-Hydroxybenzoyl-CoA reductase (4-HBCR) is a key enzyme in the anaerobic metabolism of phenolic compounds. It catalyzes the reductive removal of the hydroxyl group from the aromatic ring yielding benzoyl-CoA and water. The subunit architecture, amino acid sequence, and the cofactor/metal content indicate that it belongs to the xanthine oxidase (XO) family of molybdenum cofactor-containing enzymes. 4-HBCR is an unusual XO family member as it catalyzes the irreversible reduction of a CoA-thioester substrate. A radical mechanism has been proposed for the enzymatic removal of phenolic hydroxyl groups. In this work we studied the spectroscopic and electrochemical properties of 4-HBCR by EPR and M?ssbauer spectroscopy and identified the pterin cofactor as molybdopterin mononucleotide. In addition to two different [2Fe-2S] clusters, one FAD and one molybdenum species per monomer, we also identified a [4Fe-4S] cluster/monomer, which is unique among members of the XO family. The reduced [4Fe-4S] cluster interacted magnetically with the Mo(V) species, suggesting that the centers are in close proximity, (<15 A apart). Additionally, reduction of the [4Fe-4S] cluster resulted in a loss of the EPR signals of the [2Fe-2S] clusters probably because of magnetic interactions between the Fe-S clusters as evidenced in power saturation studies. The Mo(V) EPR signals of 4-HBCR were typical for XO family members. Under steady-state conditions of substrate reduction, in the presence of excess dithionite, the [4Fe-4S] clusters were in the fully oxidized state while the [2Fe-2S] clusters remained reduced. The redox potentials of the redox cofactors were determined to be: [2Fe-2S](+1/+2) I, -205 mV; [2Fe-2S] (+1/+2) II, -255 mV; FAD/FADH( small middle dot)/FADH, -250 mV/-470 mV; [4Fe-4S](+1/+2), -465 mV and Mo(VI)/(V)/(VI), -380 mV/-500 mV. A catalytic cycle is proposed that takes into account the common properties of molybdenum cofactor enzymes and the special one-electron chemistry of dehydroxylation of phenolic compounds.     

Genotypic analyses of Escherichia coli O157:H7 and O157 nonmotile isolates recovered from beef cattle and carcasses at processing plants in the Midwestern states of the United States

Escherichia coli O157:H7 and O157 nonmotile isolates (E. coli O157) previously were recovered from feces, hides, and carcasses at four large Midwestern beef processing plants (R. O. Elder, J. E. Keen, G. R. Siragusa, G. A. Barkocy-Gallagher, M. Koohmaraie, and W. W. Laegreid, Proc. Natl. Acad. Sci. USA 97:2999-3003, 2000). The study implied relationships between cattle infection and carcass contamination within single-source lots as well as between preevisceration and postprocessing carcass contamination, based on prevalence. These relationships now have been verified based on identification of isolates by genomic fingerprinting. E. coli O157 isolates from all positive samples were analyzed by pulsed-field gel electrophoresis of genomic DNA after digestion with XbaI. Seventy-seven individual subtypes (fingerprint patterns) grouping into 47 types were discerned among 343 isolates. Comparison of the fingerprint patterns revealed three clusters of isolates, two of which were closely related to each other. Remarkably, isolates carrying both Shiga toxin genes and nonmotile isolates largely fell into specific clusters. Within lots analyzed, 68.2% of the postharvest (carcass) isolates matched preharvest (animal) isolates. For individual carcasses, 65.3 and 66.7% of the isolates recovered postevisceration and in the cooler, respectively, matched those recovered preevisceration. Multiple isolates were analyzed from some carcass samples and were found to include strains with different genotypes. This study suggests that most E. coli O157 carcass contamination originates from animals within the same lot and not from cross-contamination between lots. In addition, the data demonstrate that most carcass contamination occurs very early during processing.     

Bacterial Transformations of Naphthothiophenes

Naphthothiophenes are minor components of fossil fuels, and they can enter the environment from oil spills. Naphtho[2,1-b]thiophene, naphtho[2,3-b]thiophene, and 1-methylnaphtho[2,1-b]thiophene were synthesized and used in biodegradation studies with 1-methylnaphthalene (1-MN)-degrading Pseudomonas strains W1, F, and BT1. Cultures were incubated with one of the naphthothiophenes with or without 1-MN, acidified, and extracted with CH(inf2)Cl(inf2). The extracts were analyzed by gas chromatography with flame photometric and mass detectors to characterize sulfur-containing metabolites and with an atomic emission detector for quantification. Only strain W1 was able to grow on naphtho[2,1-b]thiophene, but strains F and BT1 cometabolized this compound if 1-MN was present. 1-MN was required by all three strains to metabolize naphtho[2,3-b]thiophene, which was more resistant to biodegradation than the [2,1-b] isomer. Two metabolites of naphtho [2,1-b]thiophene were purified, analyzed by (sup1)H nuclear magnetic resonance spectroscopy, and found to be 4-hydroxybenzothiophene-5-carboxylic acid (metabolite I) and 5-hydroxybenzothiophene-4-carboxylic acid (metabolite II). In cultures of strain W1 grown for 7 days on 52 (mu)mol of naphtho[2,1-b]thiophene, >84% of the substrate was degraded and metabolites I and II accounted for 19 and 9%, respectively, of the original amount of naphtho[2,1-b]thiophene. When 1-MN was present, strain W1 degraded >97% of the naphtho[2,1-b]thiophene and similar amounts of metabolite II were produced, but metabolite I did not accumulate. 1-MN was shown to promote the further degradation of metabolite I, but not of metabolite II, by strain W1. Thus, 1-MN enhanced the biodegradation of naphtho[2,1-b]thiophene. Approximately 70% of the 1-methylnaphtho [2,1-b]thiophene added to cultures of strain W1 with 1-MN was recovered as 4-hydroxy-3-methylbenzothiophene-5-carboxylic acid, the 3-methyl analog of metabolite I. The methyl substitution hindered further metabolism of 3-methyl-metabolite I even in the presence of 1-MN. Cometabolism of naphtho[2,3-b]thiophene yielded two products that were tentatively identified as 5-hydroxybenzothiophene-6-carboxylic and 6-hydroxybenzothiophene-5-carboxylic acids.     

Diversity of multidrug-resistant salmonella enterica strains associated with cattle at harvest in the United States

The prevalence and diversity of multidrug-resistant (MDR) Salmonella enterica strains associated with cattle at harvest in the United States were examined. Hides and carcasses of cattle were sampled at processing plants (n = 6) located in four geographically distant regions from July 2005 to April 2006. The mean prevalences of Salmonella on hides, preevisceration carcasses (immediately after hide removal), and postintervention carcasses (in the chiller and after the full complement of interventions) were 89.6%, 50.2%, and 0.8%, respectively. The values for MDR Salmonella enterica strains (defined as those resistant to two or more antimicrobials) as percentages of Salmonella prevalence were 16.7% (95% confidence interval [CI], 8.3 to 25.1%; median percent prevalence, 6.9%), 11.7% (95% CI, 4.4 to 19.0%; median, 4.8%), and 0.33% (95% CI, -0.3 to 0.70%; median, 0%), respectively. In this study, 16,218 Salmonella hide and carcass isolates were screened for antimicrobial resistance. Of these, 978 (6.0%) unique MDR S. enterica isolates were identified and serotyped and their XbaI pulsed-field gel electrophoresis (PFGE) profiles determined. The predominant MDR S. enterica serotypes observed were Newport (53.1%), Typhimurium (16.6%), and Uganda (10.9%). Differences in MDR S. enterica prevalence were detected, and PFGE analysis revealed both epidemic clusters (profiles found in plants in multiple regions/seasons) and endemic clusters (profiles observed in plants in limited regions/seasons) within several of the MDR serotypes examined. Despite these differences, multiple-hurdle processing interventions employed at all plants were found to be quite effective and decreased Salmonella carcass contamination by 98.4% (95% CI, 97.6 to 99.7%).     

Nucleic Acid Homologies Among Oxidase-Negative Moraxella Species

The deoxyribonucleic acid (DNA) base composition and DNA homologies of more than 40 strains of oxidase-negative Moraxella species were determined. These bacteria have also been identified as belonging to the Mima-Herellea-Acinetobacter group and the Bacterium anitratum group, as well as to several other genera including Achromobacter and Alcaligenes. The DNA base content of these strains ranged from 40 to 46% guanine plus cytosine. DNA-DNA competition experiments distinguished five groups whose members were determined by showing 50% or more homology to one of the reference strains: B. anitratum type B5W, Achromobacter haemolyticus var. haemolyticus, Alcaligenes haemolysans, Achromobacter metalcaligenes, and Moraxella lwoffi. A sixth group comprised those strains showing less than 50% homology to any of the reference strains. Negligible homology was found between strains of oxidase-negative and oxidase-positive Moraxella species in DNA-DNA competition experiments. However, evidence of a distant relationship between the two groups was obtained in competition experiments by using ribosomal ribonucleic acid.     

Characterization of 15 selected coccal bacteria isolated from antarctic rock and soil samples from the McMurdo-Dry Valleys (South-Victoria Land)

Summary Approximately 1500 cultures of microorganisms were isolated from rocks and soils of the Ross Desert (McMurdo-Dry Valleys). From these, 15 coccoid strains were chosen for more detailed investigation. They were characterized by morphological, physiological and chemotaxonomical properties. All isolates were Grampositive, catalase-positive and nonmotile. Six strains showed red pigmentation and could be identified as members of the genera Micrococcus (M. roseus, M. agilis) or Deinococcus. In spite of their coccoid morphology, the remaining nine strains had to be associated with coryneform bacteria (Arthrobacter, Brevibacterium), because of their cell wall composition and G+C ratios. Most of the strains were psychrotrophic, but one strain was even obligately psychrophilic, with a temperature maximum below 20°C. Red cocci had in vitro pH optima above 9.0 although they generally originated from acid samples. Most isolates showed a preference for sugar alcohols and organic acids, compounds which are commonly known to be released by lichens, molds and algae, the other components of the cryptoendolithic ecosystem. These properties indicate that our strains are autochthonous members of the natural Antarctic microbial population.     

Genotypic Analyses of Escherichia coli O157:H7 and O157 Nonmotile Isolates Recovered from Beef Cattle and Carcasses at Processing Plants in the Midwestern States of the United States

Escherichia coli O157:H7 and O157 nonmotile isolates (E. coli O157) previously were recovered from feces, hides, and carcasses at four large Midwestern beef processing plants (R. O. Elder, J. E. Keen, G. R. Siragusa, G. A. Barkocy-Gallagher, M. Koohmaraie, and W. W. Laegreid, Proc. Natl. Acad. Sci. USA 97:2999–3003, 2000). The study implied relationships between cattle infection and carcass contamination within single-source lots as well as between preevisceration and postprocessing carcass contamination, based on prevalence. These relationships now have been verified based on identification of isolates by genomic fingerprinting. E. coli O157 isolates from all positive samples were analyzed by pulsed-field gel electrophoresis of genomic DNA after digestion with XbaI. Seventy-seven individual subtypes (fingerprint patterns) grouping into 47 types were discerned among 343 isolates. Comparison of the fingerprint patterns revealed three clusters of isolates, two of which were closely related to each other. Remarkably, isolates carrying both Shiga toxin genes and nonmotile isolates largely fell into specific clusters. Within lots analyzed, 68.2% of the postharvest (carcass) isolates matched preharvest (animal) isolates. For individual carcasses, 65.3 and 66.7% of the isolates recovered postevisceration and in the cooler, respectively, matched those recovered preevisceration. Multiple isolates were analyzed from some carcass samples and were found to include strains with different genotypes. This study suggests that most E. coli O157 carcass contamination originates from animals within the same lot and not from cross-contamination between lots. In addition, the data demonstrate that most carcass contamination occurs very early during processing.     

The aerobic psychotrophic populations on meat and meat contact surfaces in a meat production system and on meat stored at chill temperatures

At a city abattoir, a wholesaler and 10 different supermarkets, surface microbiological samples were taken of carcasses, hands and apron fronts of members of staff and equipment (mincers and saws). In addition, minced meat, packaged and displayed in chilled cabinets, was also sampled. Carcasses, personnel surfaces and equipment were monitored by a modified agar sausage technique. From each of the highest dilution psychotrophic plate counts, five colonies were selected randomly, isolated and identified (1265 in total). Microbes developing on chilled meat were also isolated from other surfaces in the production chain. On chilled meat (51%) and at the abattoir (36%) pseudomonads were the predominant organisms followed by the Gram-positive cocci on chilled meat and by Acinetobacter, Moraxella and Alcaligenes spp. at the abattoir. At the wholesaler Gram-positive cocci (32%) predominated, followed by Alcaligenes, Moraxella and Alcaligenes spp. Pseudomonas, Alcaligenes, Neisseriaceae and related genera, Gram-positive cocci, species from the coryneform groups of bacteria and yeasts were identified from all the surfaces monitored. Identification with the API NE20 was unsatisfactory. Enterbacteriaceae, lactobacilli and endospore-forming bacteria were identified occasionally, but their significance as contaminating organisms seems low. No Salmonella spp. were identified.     

The aerobic psychrotrophic populations on meat and meat contact surfaces in a meat production system and on meat stored at chill temperatures

At a city abattoir, a wholesaler and 10 different supermarkets, surface microbiological samples were taken of carcasses, hands and apron fronts of members of staff and equipment (mincers and saws). In addition, minced meat, packaged and displayed in chilled cabinets, was also sampled. Carcasses, personnel surfaces and equipment were monitored by a modified agar sausage technique. From each of the highest dilution psychrotrophic plate counts, five colonies were selected randomly, isolated and identified (1265 in total). Microbes developing on chilled meat were also isolated from other surfaces in the production chain. On chilled meat (51%) and at the abattoir (36%) pseudomonads were the predominant organisms followed by the Gram-positive cocci on chilled meat and by Acinetobacter, Moraxella and Alcaligenes spp. at the abattoir. At the wholesaler Gram-positive cocci (32%) predominated, followed by Alcaligenes, Moraxella and Alcaligenes spp. Pseudomonas, Alcaligenes, Neisseriaceae and related genera, Gram-positive cocci, species from the coryneform groups of bacteria and yeasts were identified from all the surfaces monitored. Identification with the API NE20 was unsatisfactory. Enterbacteriaceae, lactobacilli and endospore-forming bacteria were identified occasionally, but their significance as contaminating organisms seems low. No Salmonella spp. were identified. and accepted 25 July 1989     

First description of nonmotile Vibrio vulnificus strains virulent for eels

Nonmotile Vibrio vulnificus strains were isolated as pure cultures from body ulcers and internal organs of wild diseased European eels caught in a Mediterranean freshwater coastal lagoon. All 54 V. vulnificus isolates were nonmotile, indole-, ornithine decarboxilase-, mannitol- and cellobiose-positive, developed the opaque variant in culture, belonged to the O-antigenic serovar A and were highly virulent for eels by both intraperitoneal injection and immersion challenges. The nonmotile phenotype found in our V. vulnificus isolates was stable: nonmotile cells were always recovered from experimentally infected eels; no variation in the immobility of the V. vulnificus cells was observed for repeated subculture by daily passages on solid media, at different temperatures or incubation times and with or without magnesium sulfate. Many of the fla genes of Vibrio were present in the genome of the nonmotile strains (flaCDE and flaFBA for flagellins and flaH for the distal capping protein), although we observed by transmission electron microscopy that these V. vulnificus strains always lacked the polar flagellum. This is the first report on the existence of nonmotile wild-type V. vulnificus strains.     

Simple Genetic Transformation Assay for Rapid Diagnosis of Moraxella osloensis

A genetic transformation assay for unequivocal identification of strains of Moraxella osloensis is described. In this assay a stable tryptophan auxotroph is transformed to prototrophy by deoxyribonucleic acid (DNA) samples from other strains of M. osloensis but not by DNA samples from unrelated bacteria. The test is simple to perform and definitive results can be obtained in less than 24 h. The procedure, which is suitable for routine diagnosis in a clinical laboratory, involves a rapid method for preparation of crude transforming DNA from small quantities of bacterial cells and permits simultaneous examination of large numbers of isolated cultures. The assay was shown to correctly identify 27 strains previously classified as M. osloensis. Forty-five other gram-negative, oxidase-positive, nonmotile coccobacilli, which might be confused with M. osloensis unless subject to more extensive testing, were shown to be unrelated genetically to M. osloensis. The transformation assay clearly distinguishes M. osloensis from Acinetobacter. Although most strains of M. osloensis are nonfastidious, being able to grow in a mineral medium supplemented with a single organic carbon source, one of the strains tested was only able to grow on fairly complex media and could not be transformed to grow on simple media. Inability to alkalize Simmons citrate agar was shown not to be characteristic of all strains of M. osloensis.     

骆驼瘤胃耐受/降解去氢骆驼蓬碱细菌的筛选

【目的】中药骆驼蓬含多种生物碱,对动物有毒性。生活于荒漠半荒漠的骆驼可采食部分有毒植物而不中毒。为了解骆驼瘤胃微生物对骆驼蓬植物毒素的耐受与降解能力进行本研究。【方法】以含100mg/L纯品去氢骆驼蓬碱的M98-5培养基接种骆驼瘤胃内容物,经五代胁迫培养后分离可耐受/降解去氢骆驼蓬碱的细菌,以薄层析法检验其降解活力,以16SrRNA序列分析其进化地位。【结果】29个分离株中15株具有降解去氢骆驼蓬碱活性;16SrRNA序列分析显示,属于乳杆菌属(Lactobacillus)16株,占55%;志贺氏菌属(Shigella)7株,占24%;芽孢杆菌属(Bacillus)4株,占13.8%;肠球菌属(Enterococcus)和巨型肠球菌属(Megasphaera)各1株。【结论】可耐受/降解去氢骆驼蓬碱的骆驼瘤胃细菌仅限于少数几类,且检测到的具有降解活力的只有乳杆菌类。