Lactic acid bacteria isolated from soy sauce mash in Thailand

Fourteen sphere-shaped and 30 rod-shaped lactic acid bacteria were isolated from soy sauce mash of two factories in Thailand. These strains were separated into two groups, Group A and Group B, by cell shape and DNA-DNA similarity. Group A contained 14 tetrad-forming strains, and these strains were identified as Tetragenococcus halophilus by DNA similarity. Group B contained 30 rod-shaped bacteria, and they were further divided into four Subgroups, B1, B2, B3, and B4, and three ungrouped strains by phenotypic characteristics and DNA similarity. Subgroup B1 contained 16 strains, and these strains were identified as Lactobacillus acidipiscis by DNA similarity. Subgroup B2 included two strains, and the strains were identified as Lactobacillus farciminis by DNA similarity. Subgroup B3 contained five strains. The strains had meso-diaminopimelic acid in the cell wall, and were identified as Lactobacillus pentosus by DNA similarity. The strains tested produced DL-lactic acid from D-glucose. Subgroup B4 contained four strains. The strains had meso-diaminopimelic acid in the cell wall, and they were identified as Lactobacillus plantarum by DNA similarity. Two ungrouped strains were homofermentative, and one was heterofermentative. They showed a low degree of DNA similarity with the type strains tested, and were left unnamed. The distribution of lactic acid bacteria in soy sauce mash in Thailand is discussed.     

The recA+ gene product is more important than catalase and superoxide dismutase in protecting Escherichia coli against hydrogen peroxide toxicity.

Various deoxyribonucleic acid repair-deficient strains of Escherichia coli K-12 were exposed to hydrogen peroxide under anaerobic conling of the strains was determined. The level of catalase, peroxidase, and superoxide dismutase in cell-free extracts of the strains as well as the capacity of intact cells to decompose hydrogen peroxide were assayed, recA strains were more rapidly killed than other strains with deoxyribonucleic acid repair deficiencies. There was no correlation between the killing rate of the strains and the capacity of intact cells to decompose hydrogen peroxide or the level of catalase and superoxide dismutase in cell-free extracts. The level of peroxidase in cell-free extract was too low to be determined.     

The interchangeability of siderophores in the Enterococcus genus

The functional interchangeability of siderophores was tested among 62 strais belonging to 12 species of genus Enterococcus. Most investigated strains were from E. faecalis and E. faecium species. The majority of examined enterococcal strains appeared highly resistant to EDDA (ethylene-di-amine-di-ortho-hydroxyphenylacetic acid), therefore the group of sensitive strains involved only 11 used as indicator strains. The determination of interchangeability of siderophores within enterococcal strains was performed using EDDA-agar media into which the indicator strains were included. Test colonies (donor strains) were applied to the surface of the media to determine whether the indicator organisms could obtain the required iron for growth by utilizing chelators from the test colony. Only two strains: E. solitarius DSM 5634 and E. pseudoavium DSM 5632 did not demonstrate the ability to utilize siderophores synthesized by all investigated strains. The other tested indicator strains appeared to be recipients of siderophores from 20-52 donor enterococcal strains. The ability to exchange siderophores in enterococci was found as the feature characterizing individual strains.     

Synergistic activity of gentamicin plus carbenicillin upon Pseudomonas aeruginosa: its relationship with pyocin and antibiotic susceptibility.

The synergistic effect of combinations of gentamicin and carbenicillin, as well as the type or subtype of the pyocins produced, were investigated in 170 strains of Pseudomonas aeruginosa isolated from clinical specimens. A high proportion of strains were synergistically inhibited (73.5%), but among strains producing pyocins 7, 14 and 31, synergy was infrequent or absent. The synergistic effect was more frequent upon gentamicin- or carbenicillin-susceptible strains. However, among untypable strains, synergy was more frequent among gentamicin-resistant strains. Susceptibility to both gentamicin and carbenicillin must be considered if antibiotic susceptibility is to be related to synergy.     

Comparison of two methods for serotyping Ureaplasma urealyticum clinical isolates

A newly developed enzyme linked immunosorbent assay (ELISA) method using monoclonal antibodies (MAbs) to the 14 serotypes of Ureaplasma urealyticum was compared to immunofluorescence assay (IFA) for serotyping U. urealyticum clinical isolates. Of the 102 vaginal isolates of U. urealyticum, five strains were lost and were excluded from analysis. Of the 97 strains analysed, a total of 86 (89%) strains were typeable by ELISA and a total of 89 (92%) strains were typeable by IFA. Eighty-six strains were typeable by both methods, three by IFA only and eight strains were not typeable neither by ELISA nor by IFA. Of the 86 strains typeable by both methods, complete concordance in serotyping results was found. The three strains not typeable by ELISA were typeable as serotype 4 by IFA. These three strains were reanalysed by ELISA after major modifications of the antigen preparation and were typeable as serotype 4. In conclusion, the ELISA was found suitable for serotyping clinical isolates. However, since the ELISA had a somewhat lower performance than IFA, strains not typeable by ELISA, should be retested by another technique such as IFA.     

Characteristics of E.coli O157 strains isolated in Poland from clinical material and food samples

E. coli belonging to the O157 serological group are among the organisms isolated most frequently out of all the so called entero-hemorrhagic E. coli strains (EHEC). Since several years they have been isolated also in Poland. The purpose of the present study was determination on selected phenotypic and genotypic properties of E. coli O157 strains isolated in our country from clinical material samples and from food. The serotype of the strains was determined, together with the following properties regarded as pathogenicity markers of verotoxic E. coli strains such as absence of beta-glucuronidase activity and sorbitol fermentation ability, as well as production of verotoxins SLT I and/or SLT II and entero-hemolysin. Besides that, by the PCR method the fragments of the genes coding for verotoxins, intimin and enterohaemolysin were amplified. The products of PCR were analysed by the restriction enzyme analysis (RFLP). All verotoxic E. coli O157 strains isolated in Poland were analysed by the pulsed field gel electrophoresis of genomic DNA (PFGE). The studied group comprised E. coli O157 strains, among them 40 strains were isolated from human faeces and 5 from food. The remaining strains were the reference E. coli O157:H7 EDL 933 and G 5244 strains and strains from NIH collection. The obtained results showed that the tested strains were a very varying population. 21 of them (all isolated from food, 11 from faeces and 5 reference strains) belonged to serotype O157:H7, five were not peritrichous O157:NM and the remaining ones had other ciliary antigen than H7. All strains isolated from food, reference strains and only 3 O157:NM strains isolated from humans were verotoxic. The strains from food and two reference strains produced only SLT II, 2 of 3 strains isolated from humans and one reference strain also produced only SLT II and the other produced both verotoxins. Apart from these 13 verotoxic strains all remaining strains caused sorbitol fermentation.     

替加环素与多粘菌素B对泛耐药鲍曼不动杆菌体外研究

目的为治愈耐舒普深的泛耐药鲍曼不动杆菌（PDR-Ab）提供新药。方法替加环素采用二倍琼脂稀释法,多粘菌素B用E-test条法测分离目标菌株100株的最低抑菌浓度（M IC）,并用WHONET 5.4软件分析数据。结果多粘菌素B对耐舒普深的泛耐药鲍曼不动杆菌株的M IC值分布情况为：1.5 mg/L为2株,1.0 mg/L为9株,0.75 mg/L为9株,0.5 mg/L为38株,0.38 mg/L为34株,0.25 mg/L为8株,均为敏感;替加环素对耐舒普深的泛耐药鲍曼不动杆菌株的M IC值分布情况为：≥32 mg/L为0株、16 mg/L为2株、8 mg/L为3株、4 mg/L为4株、2 mg/L为6株、1 mg/L为9株、0.5 mg/L为30株、0.25 mg/L为33株、0.125 mg/L为9株、0.06 mg/L为2株、0.03 mg/L为2株,敏感率为95.0%,中敏率为3.0%,耐药率为2.0%。结论替加环素或多粘菌素B是目前对耐舒普深的泛耐药鲍曼不动杆菌最有效药物之一。     

Phenotypic and molecular characterization of Lactococcus lactis from milk and plants

AIMS: The aim of this study was to obtain new Lactococcus lactis strains from nondairy materials for use as milk fermentation starters. The genetic and phenotypic traits of the obtained strains were characterized and compared with those of L. lactis strains derived from milk. It was confirmed that the plant-derived bacteria could be used as milk fermentation starters. METHODS AND RESULTS: About 2600 lactic acid bacteria were subjected to screening for L. lactis with species-specific PCR. Specific DNA amplification was observed in 106 isolates. Forty-one strains were selected, including 30 strains of milk-derived and 11 of plant-derived, and their phenotypic traits and genetic profiles were determined. The plant-derived strains showed tolerance for high salt concentration and high pH value, and fermented many more kinds of carbohydrates than the milk-derived strains. There were no remarkable differences in the profiles of enzymes, such as lipases, peptidases and phosphatases. Isolates were investigated by cluster analysis based on randomly amplified polymorphic DNA profiles. There were no significant differences between isolates from milk and those from plant. The L. lactis subsp. cremoris strains were clustered into two distinct groups, one composed of the strains having the typical cremoris phenotype and the other composed of strains having a phenotype similar to subsp. lactis. Fermented milk manufactured using the plant-derived strains were not inferior in flavour to that manufactured using the milk-derived strains. CONCLUSIONS: Plant-derived L. lactis strains are genetically close to milk-derived strains but have various additional capabilities, such as the ability to ferment many additional kinds of carbohydrates and greater stress-tolerance compared with the milk-derived strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The lactic acid bacteria obtained from plants in this study may be applicable for use in the dairy product industry.     

Antibiotic resistance of staphylococci isolated from outpatients

The aim of the study was to determine susceptibility of 587 strains of S. aureus and 85 strains of coagulase-negative staphylococci isolated from outpatients in Poznań to co-trimoxazole, amoxycillin/clavulanic acid, erythromycin, gentamycin, doxycycline, ampicillin, oxacillin, cephradine, clindamycin and neomycin. Also methicillin-resistant strains were determined as well as strains ability to produce beta-lactamases. Susceptibility testing and examination of methicillin-resistant strains were performed by the disc diffusion techniques according to recommendation of NCCLS. Methicillin-resistant strains were additionally examined to their sensitivity to vankomycin and teicoplanin. beta-lactamase production was detected using nitrocefin impregnated discs and iodometric method. Amoxacillin/clavulanic acid, gentamycin, co-trimoxazole, cephradin, oxacillin and clindamycin occurred to be very active against both, S. aureus and coagulase-negative staphylococci. 84.7% to 100% of examined strains were sensitive to these drugs. Doxycyclin, erythromycin and ampicillin were less effective. Nine strains (1.5%) of 587 strains of S. aureus as well as 7 strains (8.7%) of coagulase-negative staphylococci were methicillin-resistant. All of methicillin-resistant strains were sensitive to vancomycin and teicoplanin. More than 75% of S. aureus and close to 50% of coagulase-negative staphylococci were able to produce beta-lactamases.     

Classification and identification of Mycobacterium africanum by pyrolysis mass spectrometry

Pyrolysis mass spectrometry was used to classify and identify strains of Mycobacterium africanum and of M. tuberculosis, M. bovis and M. bovis BCG. The multicharacter mass pyrograms were evaluated by computerized data handling procedures that were suited for classification and identification. The results revealed considerable heterogeneity among the African strains, which was shown to be linked to the geographic distribution of the strains. On the basis of a routine mass spectrometric identification key the African strains were identified without exception as belonging to, what is referred to as the 'Tuberculosis complex' (i.e. the clinically relevant group formed by strains of M. Tuberculosis, M. bovis and M. bovis BCG). Classification of the strains by means of discriminant analysis indicated an intermediate clustering for the majority of the African strains and overlap for some African strains with in particular M. bovis. It was concluded that from the mass spectrometric data a species status for the group of African strains was not justifiable.     

Conjugative transfer of glycopeptide and macrolide resistant genes among Enterococci and from Enterococcus faecalis to Staphylococcus aureus

The resistance determinants were transferred from clinical strains of enterococci to Staphylococcus aureus strains. As recipients methicillin-resistant and methicillin-susceptible strains were used and the filter-mating procedure was performed. The transconjugants resistant to erythromycin were obtained in the case of all recipients, in one case the vanA determinant conferring the resistance to vancomycin was transferred together with erythromycin resistance. However the resistance was very unstable and the level was not as high as in the case of Enterococcus faecalis donor strain. The vanA determinant was easily transferred between enterococcal strains by the conjugation and a transfer occurred of vanA alone or together with erythromycin resistance.     

Iron uptake by Pasteurella piscicida and its role in pathogenicity for fish.

We evaluated the iron uptake mechanisms in Pasteurella piscicida strains as well as the effect of iron overload on the virulence of these strains for fish. With this aim, the capacity of the strains to obtain iron from transferrin and heme compounds as well as their ability to overcome the inhibitory activity of fish serum was analyzed. All the P. piscicida strains grew in the presence of the iron chelator ethylene-diamine-di (O-hydroxyphenyl acetic acid) or of human transferrin, which was used by a siderophore-mediated mechanism. The chemical tests and cross-feeding assays showed that P. piscicida produced a siderophore which was neither a phenolate nor a hydroxamate. Cross-feeding assays as well as preliminary chromatographic analysis suggest that this siderophore may be chemically related to multocidin. All the P. piscicida isolates utilized hemin and hemoglobin as an iron source, since the virulence of the strains increased when the fish were preinoculated with these compounds. This effect was stronger in the avirulent strains (50% lethal dose was reduced by 4 logs when fish were pretreated with hemin or hemoglobin). Only the pathogenic P. piscicida isolates were resistant to the bactericidal action of the fresh fish serum. The nonpathogenic strains grew in fish serum only when it was heat-inactivated or when it was supplemented with ferric ammonium citrate, hemin, or hemoglobin. In all the strains, at least three iron-regulated outer membrane proteins (IROMPs) (105, 118, and 145 kDa) were increased when the strains were cultured in iron-restricted medium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of the competitiveness of fast-growing rhizobia infectingAcacia senegal using antibiotic resistance and melanin production as identification markers

The competitiveness of fourRhizobium sp. strains infectingAcacia senegal and originating in the Sudan was assessed in a growth chamber experiment using Sudanese soil, WhenAcacia senegal was inoculated with pure cultures of the strains, there were statistically significant differences among the strains with respect to the numbers of nodules formed, the amount of dry matter produced and acetylene reduction activity. However, the best strain when applied as a pure culture, was only the second best as a competitor. Two strains with inferior symbiotic capabilities were also bad competitors but nevertheless reduced the yields of the plants when they were applied as inocula mixed with the better strains. The bacterial markers used to assess nodule occupancy were resistance to streptomycin or spectinomycin. Two of the strains formed the dark-brown pigment melanin. Melanin production was a stable characeristic, well suited to serve as an intrinsic identification marker when assessing the competitiveness of melanin-producing versus non-producing strains in controlled conditions.     

Presence of various Acinetobacter species in urinary tract infections

Species classification of 39 strains of Acinetobacter isolated from urinary tract infections (UTI) was performed by API 20NE tests. On the whole 24 biotypes were differentiated which formed 4 species and one biotype had no defined species classification. Acinetobacter baumani was most numerously represented. Seventy seven percent of strains were isolated from urine samples from women. About 90% of Acinetobacter strains were isolated as single pathogens. Sensitivity of these strains to 23 antibiotics and chemotherapeutics using ATB-UR and disc diffusion technique was evaluated. Of all cephalosporins tested ceftazidime was the most active. All strains tested were sensitive to imepenem. The high percentage of strains was sensitive to quinolones of IIIrd generation. The high percentage of strains was resistant to nitrofurantoin.     

Lysogenic conversion for multiple characters in a strain of Staphylococcus aureus.

Lysogenization of nonlysogenic strains of Staphylococcus aureus was performed with two different bacteriophages, LS1 and LS2, that were unable to plaque on any of the strains of S. aureus tested. Infection of recipient strains was achieved when protoplasts were inoculated with LS1 or LS2 or when bacterial cultures were simultaneously inoculated with a virulent phage together with LS1 or LS2. Lysogenization was demonstrated by changes in phenotypic characters of the host strain and by liberation of bacteriophages from the modified strains as shown by electron microscopic examination. The lysogenic strains differed from the host strains by the following characters: they were coagulase, deoxyribonuclease, and lipase negative; they were untypable by the basic set of phages; they did not ferment mannitol under anaerobic conditions; and they produced only l-(+)-lactic acid by glucose fermentation. Their cell walls contained less glycine and concomitantly more serine than those of the host strains. Furthermore, they were devoid of protein A. Conversely, some antigenic factors as well as the presence of ribitol in the cell wall teichoic acid, indicated a parental relationship between the host strains and the derived lysogenic ones. Phages LS1 and LS2 could be excluded from the lysogenic strains by invading phages, and the revertant nonlysogenic strains recovered all of the characteristics of the initial host strains. It was thus concluded that the phenomenon described was due to lysogenic conversion. The origin of phages LS1 and LS2 is discussed.     

Antibiotic sensitivity of beta-hemolytic streptococci isolated from throat swabs and purulent material

The aim of this study was to evaluate the prevalence and susceptibility of beta-hemolytic streptococci isolated from throat swabs (142--29.9%) and purulent material (333--70.1%) taken from patients treated at University Hospital dr. A. Jurasz in Bydgoszcz Collegium Medicum. L. Rydygier in Bydgoszcz, Nicolaus Copernicus University in Torun in 2005-2009. Of the 475 tested strains, 156 (32.8%) were identified as S. pyogenes. This species accounted for 38.8% of strains isolated from purulent material and 19.0% of swabs from the throat. Among the strains isolated from throat swabs of 62 (43.7%) were identified as Streptococcus group C. Only 5.1% strains were identified as Streptococcus group F. All strains of beta-hemolytic streptococci were susceptible to ampicillin or penicillin, fluoroquinolones, vancomycin and linezolid. Erythromycin-susceptible strains was 83.8%, and 89.1% for clindamycin. A total of 51.3% of erythromycin resistance strains had the cMLS(B) phenotype (63.3% for strains from throat swabs and 46.3% of the purulent materials). Sensitivity to tetracycline was characterized by 51.2% of strains of beta-hemolytic streptococci. The percentage of strains susceptible to this antibiotic among isolates from throat swabs was 63.1%, and purulent material--48.0%. The lowest percentage of strains susceptible to tetracycline (14.1%) were found among S. agalactiae and Streptococcus group G (33.6%) strains. During the study time, saw an increase in the percentage of strains susceptible to tetracycline and erythromycin.     

Analysis of integrons in human isolates of Salmonella enterica serovar typhimurium isolated in the Slovak Republic

About 110 sporadic, epidemiologically unrelated Salmonella enterica serovar typhimurium strains isolated in the Slovak Republic were analyzed for the presence of integrons. Of these 110 examined strains, 47 were of definitive phage type DT104 and 63 were strains of various phage type, RDNC and untypeable, designated here as non-DT104 strains. All isolates were also tested for antimicrobial resistance to 10 antibiotics as well as for the presence of virulence plasmid. Of 63 non-DT104 strains, 15 isolates were multiple-resistant, independently from phage type, other strains were resistant to one, two or three drugs. Resistance to ampicillin, streptomycin, tetracycline and sulfisoxazole was most frequently observed. Among the DT104 isolates up 65.9% exhibited characteristic pentaresistance--ACSSuT phenotype. The integron content was studied in PCR experiments using a 5'-CS/3'-CS primer pair. Fourteen non-DT104 strains, independently from phage type, were found to carry integrons with amplicons 650-1900 bp in size. Thirty-six DT104 strains contained integrons of 1000 and 1200 bp and 31 of they exhibited the ACSSuT phenotype. No integron was found in 10 DT104 strains, which included strains mostly resistant only to streptomycin, tetracycline and sulfisoxazole. The majority of non-DT104 strains did not possess any integrons. Our findings show the widespread existence of both resistant and multiple-resistant epidemiologically unrelated Salmonella typhimurium strains and suggest that integrons contribute to this antimicrobial resistance. The presence of 90-kb virulence plasmid in the 54 non-DT104 and in the all DT104 strains was found.     

深红酵母相关菌株全细胞长链脂肪酸的分析及其数值分类

从黄海和渤海海水中分离到15株红酵母,初步定名为深红酵母(Rhodotorula rubraLodder)对这些菌株及另外8株红酵母属对照种的形态、生理生化性状以及全细胞长链脂肪酸的组成进行了测定,并用多元统计方法对菌株间的相似性进行了计算,对菌株分群。结果表明,15株酵母之间性状存在许多差异,这些差异不能完全被鉴定性状所反映,在多元分析中15株菌不能形成紧密的聚类群。研究结果对利用个别形态和生理生化性状确定的深红酵母种的范围提出了异议。     

基于微生物同化作用的D-丙氨酸生产工艺研究

以L-丙氨酸为唯一碳氮源,从采集的若干土壤中初筛出能够降解L-丙氨酸的菌株;再以D-丙氨酸为唯一碳氮源,复筛出降解L-丙氨酸而不降解D-丙氨酸的菌株。依据菌种对DL-丙氨酸的不对称降解活性,筛选出具有最高的L-丙氨酸降解活性的菌株,并对菌株同化L-丙氨酸的反应条件进行了研究。结果表明:编号为ALA-D82的菌株具有最高的降解L-丙氨酸的能力,经鉴定为酵母菌属。在30℃,控制pH6.0,通气比1:1(V/V)和转速900 r.min-1的条件下,L-丙氨酸降解的速度最大。在最适条件下,1500 g DL-丙氨酸分两部分添加入7 L的反应液中。反应72 h后溶液中的L-丙氨酸被完全降解,提取得到D-丙氨酸晶体,产率和光学纯度分别达到92.13%和99%。     

金针菇子实体颜色的遗传规律研究

以金针菇黄色菌株F19和白色菌株F8801为亲本,原生质体单核化获得两亲本的单核菌株,配对杂交获得F1,从F1的子实体分离单孢菌株,与两亲本的原生质体单核化菌株进行回交配对,出菇观察子实体颜色,分析菇体颜色的遗传规律。研究结果表明,黄色为显性、白色为隐性,菇体颜色受一对基因(Cc)控制,与不亲和性因子A或B都没有连锁。