bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural Antibiotic Susceptibilities of
Edwardsiella tarda
,
E. ictaluri,
and
E. hoshinae
Authors: Stock Ingo , Wiedemann Bernd 
Published: July 2002

ABSTRACT

The natural antibiotic susceptibilities to 71 antibiotics of 102
Edwardsiella
strains belonging to
E. tarda
(
n
= 42),
E. ictaluri
(
n
= 41), and
E.
hoshinae
(
n
= 19) were investigated. MICs were determined using a microdilution procedure according to NCCLS criteria and German standards. All edwardsiellae were naturally sensitive to tetracyclines, aminoglycosides, most β-lactams, quinolones, antifolates, chloramphenicol, nitrofurantoin, and fosfomycin.
Edwardsiella
species were naturally resistant to macrolides, lincosamides, streptogramins, glycopeptides, rifampin, fusidic acid, and oxacillin. Although slight species-dependent differences in natural susceptibilities to some antibiotics (e.g., macrolides and cefaclor) were seen, differences in natural susceptibility affecting clinical assessment criteria were only seen with benzylpenicillin. Whereas
E. tarda
was naturally resistant to benzylpenicillin,
E. hoshinae
was naturally sensitive. Natural sensitivity and resistance to this penicillin were found among the strains of
E. ictaluri.
The observed oxacillin sensitivity of
E. ictaluri
was attributed to the failure of the species to grow at higher salt concentrations found in oxacillin-containing microtiter plates. The present study describes a database concerning the natural susceptibility of
Edwardsiella
species to a wide range of antibiotics, which can be applied to validate forthcoming antibiotic susceptibility tests of these microorganisms.
Randomized, Double-Blind, Multicenter Study of Caspofungin versus Amphotericin B for Treatment of Oropharyngeal and Esophageal Candidiases
Authors: Arathoon Eduardo G. , Gotuzzo Eduardo , Noriega L. Miguel , Berman Rayanne S. , DiNubile Mark J. , Sable Carole A. 
Published: July 2002

ABSTRACT

Caspofungin is an antifungal agent of the novel echinocandin class. We investigated its efficacy, safety, and tolerability as therapy for oropharyngeal and/or esophageal candidiasis in a phase II dose-ranging study. Patients were randomized in a double-blind manner to receive either caspofungin acetate (35, 50, or 70 mg) or amphotericin B (0.5 mg/kg of body weight) intravenously once daily for 7 to 14 days. A favorable response required both complete resolution of symptoms and quantifiable improvement of mucosal lesions 3 to 4 days after discontinuation of study drug. Efficacy was assessed using a modified intent-to-treat analysis. No hypothesis testing of efficacy was planned or performed. Of 140 enrolled patients, 63% had esophageal involvement and 98% were infected with the human immunodeficiency virus (HIV) (median CD4 count, 30/mm
3
). A modestly higher proportion of patients in each of the caspofungin groups (74 to 91%) achieved favorable responses compared to amphotericin B recipients (63%), but there was considerable overlap in the 95% confidence intervals surrounding these point estimates. Similar trends were found in the subgroups with esophageal involvement, a history of fluconazole failure, and CD4 counts of ≤50/mm
3
. A smaller proportion of patients receiving any dose of caspofungin experienced drug-related adverse events compared to patients given standard doses of conventional amphotericin B (
P
< 0.01). Caspofungin provided a generally well-tolerated parenteral therapeutic option for HIV-infected patients with oropharyngeal and/or esophageal candidiasis in this study.
Levofloxacin Penetration into Epithelial Lining Fluid as Determined by Population Pharmacokinetic Modeling and Monte Carlo Simulation
Authors: Drusano G. L. , Preston S. L. , Gotfried M. H. , Danziger L. H. , Rodvold K. A. 
Published: July 2002

ABSTRACT
Levofloxacin was administered orally to steady state to volunteers randomly in doses of 500 and 750 mg. Plasma and epithelial lining fluid (ELF) samples were obtained at 4, 12, and 24 h after the final dose. All data were comodeled in a population pharmacokinetic analysis employing BigNPEM. Penetration was evaluated from the population mean parameter vector values and from the results of a 1,000-subject Monte Carlo simulation. Evaluation from the population mean values demonstrated a penetration ratio (ELF/plasma) of 1.16. The Monte Carlo simulation provided a measure of dispersion, demonstrating a mean ratio of 3.18, with a median of 1.43 and a 95% confidence interval of 0.14 to 19.1. Population analysis with Monte Carlo simulation provides the best and least-biased estimate of penetration. It also demonstrates clearly that we can expect differences in penetration between patients. This analysis did not deal with inflammation, as it was performed in volunteers. The influence of lung pathology on penetration needs to be examined.
Molecular Evaluation of the Plasma Membrane Proton Pump fromAspergillus fumigatus
Authors: Burghoorn Henriette P. , Soteropoulos Patricia , Paderu Padmaja , Kashiwazaki Ryota , Perlin David S. 
Published: July 2002

ABSTRACTThe gene encoding the plasma membrane proton pump (H+-ATPase) ofAspergillus fumigatus,PMA1, was characterized fromA. fumigatusstrain NIH 5233 and clinical isolate H11-20. An open reading frame of 3,109 nucleotides with two introns near the N terminus predicts a protein consisting of 989 amino acids with a molecular mass of approximately 108 kDa. The predictedA. fumigatusenzyme is 89 and 51% identical to H+- ATPases ofAspergillus nidulansandSaccharomyces cerevisiae, respectively. TheA. fumigatus PMA1is a typical member of the P-type ATPase family that contains 10 predicted transmembrane segments and conserved sequence motifs TGES, CSDKTGT, MLTGD, and GDGVN within the catalytic region. The enzyme represents 2% of the total plasma membrane protein, and it is characteristically inhibited by orthovanadate, with a 50% inhibitory concentration of ∼1.8 μM. H+-ATPases fromAspergillusspp. contain a highly acidic insertion region of 60 amino acids between transmembrane segments 2 and 3, which was confirmed for the membrane-assembled enzyme with a peptide-derived antibody. An increasingA. fumigatus PMA1copy number confers enhanced growth in low-pH medium, consistent with its role as a proton pump. These results provide support for the development of theA. fumigatusH+-ATPase as a potential drug discovery target.
Characterization of VariantSalmonellaGenomic Island 1 Multidrug Resistance Regions from Serovars Typhimurium DT104 and Agona
Authors: Boyd David , Cloeckaert Axel , Chaslus-Dancla Elisabeth , Mulvey Michael R. 
Published: July 2002

ABSTRACTStrains of multidrug-resistantSalmonella entericaserovar Typhimurium DT104 (DT104) andS. entericaserovar Agona (Agona) have been found to harborSalmonellagenomic island 1 (SGI1), a 43-kb genomic region that contains many of the drug resistance genes. Such strains are resistant to ampicillin (pse-1), chloramphenicol/florfenicol (floR), streptomycin/spectinomycin (aadA2), sulfonamides (sul1), and tetracycline [tet(G)] (commonly called the ACSSuT phenotype). All five resistance genes are found in a 13-kb multidrug resistance (MDR) region consisting of an unusual class I integron structure related to In4. We examined DT104 and Agona strains that exhibited other resistance phenotypes to determine if the resistance genes were associated with variant SGI1 MDR regions. All strains were found to harbor variant SGI1-like elements by using a combination of Southern hybridization, PCR mapping, and sequencing. Variant SGI1-like elements were found with MDR regions consisting of (i) an integron consisting of the SGI1 MDR region with the addition of a region containing a putative transposase gene (orf513) anddfrA10located between duplicatedqacEΔ1/sulIgenes (SGI1-A; ACSSuTTm); (ii) an integron with either anaadA2(SSu) or apse-1(ASu) cassette (SGI1-C and SGI1-B, respectively); (iii) an integron consisting of the SGI1-C MDR region plus an orf513/dfrA10region as in SGI1-A (SGI1-D; ASSuTm; ampicillin resistance due to a TEM β-lactamase); and (iv) an integron related to that in SGI1 but which contains a 10-kb inversion between two copies of IS6100, one which is inserted infloR(SGI1-E; ASSuT). We hypothesize that the MDR of SGI1 is subject to recombinational events that lead to the various resistance phenotypes in theSalmonellastrains in which it is found.
Comparative 16S rRNA Analysis of Lake Bacterioplankton Reveals Globally Distributed Phylogenetic Clusters Including an Abundant Group of Actinobacteria
Authors: Glöckner Frank Oliver , Zaichikov Evgeny , Belkova Natalia , Denissova Ludmilla , Pernthaler Jakob , Pernthaler Annelie , Amann Rudolf 
Published: July 2002

ABSTRACT

In a search for cosmopolitan phylogenetic clusters of freshwater bacteria, we recovered a total of 190 full and partial 16S ribosomal DNA (rDNA) sequences from three different lakes (Lake Gossenköllesee, Austria; Lake Fuchskuhle, Germany; and Lake Baikal, Russia). The phylogenetic comparison with the currently available rDNA data set showed that our sequences fall into 16 clusters, which otherwise include bacterial rDNA sequences of primarily freshwater and soil, but not marine, origin. Six of the clusters were affiliated with the α, four were affiliated with the β, and one was affiliated with the γ subclass of the
Proteobacteria
; four were affiliated with the
Cytophaga-Flavobacterium-Bacteroides
group; and one was affiliated with the class
Actinobacteria
(formerly known as the high-G+C gram-positive bacteria). The latter cluster (hgcI) is monophyletic and so far includes only sequences directly retrieved from aquatic environments. Fluorescence in situ hybridization (FISH) with probes specific for the hgcI cluster showed abundances of up to 1.7 × 10
5
cells ml
−1
in Lake Gossenköllesee, with strong seasonal fluctuations, and high abundances in the two other lakes investigated. Cell size measurements revealed that
Actinobacteria
in Lake Gossenköllesee can account for up to 63% of the bacterioplankton biomass. A combination of phylogenetic analysis and FISH was used to reveal 16 globally distributed sequence clusters and to confirm the broad distribution, abundance, and high biomass of members of the class
Actinobacteria
in freshwater ecosystems.
Coliform Bacteria and Nitrogen Fixation in Pulp and Paper Mill Effluent Treatment Systems
Authors: Gauthier Francis , Neufeld Josh D. , Driscoll Brian T. , Archibald Frederick S. 
Published: July 2002

ABSTRACT

The majority of pulp and paper mills now biotreat their combined effluents using activated sludge. On the assumption that their wood-based effluents have negligible fixed N, and that activated-sludge microorganisms will not fix significant N, these mills routinely spend large amounts adding ammonia or urea to their aeration tanks (bioreactors) to permit normal biomass growth. N
2
fixation in seven Eastern Canadian pulp and paper mill effluent treatment systems was analyzed using acetylene reduction assays, quantitative nitrogenase (
nifH
) gene probing, and bacterial isolations. In situ N
2
fixation was undetectable in all seven bioreactors but was present in six associated primary clarifiers. One primary clarifier was studied in greater detail. Approximately 50% of all culturable cells in the clarifier contained
nifH
, of which >90% were
Klebsiella
strains. All primary-clarifier coliform bacteria growing on MacConkey agar were identified as klebsiellas, and all those probed contained
nifH
. In contrast, analysis of 48 random coliform isolates from other mill water system locations showed that only 24 (50%) possessed the
nifH
gene, and only 13 (27%) showed inducible N
2
-fixing activity. Thus, all the pulp and paper mill primary clarifiers tested appeared to be sites of active N
2
fixation (0.87 to 4.90 mg of N liter
−1
day
−1
) and a microbial community strongly biased toward this activity. This may also explain why coliform bacteria, especially klebsiellas, are indigenous in pulp and paper mill water systems.
Biochemical and Genetic Characterization of Coagulin, a New Antilisterial Bacteriocin in the Pediocin Family of Bacteriocins, Produced by
Bacillus coagulans
I
4
Authors: Le Marrec Claire , Hyronimus Bertrand , Bressollier Philippe , Verneuil Bernard , Urdaci Maria C. 
Published: July 2002

ABSTRACT

A plasmid-linked antimicrobial peptide, named coagulin, produced by
Bacillus coagulans
I
4
has recently been reported (B. Hyronimus, C. Le Marrec and M. C. Urdaci, J. Appl. Microbiol. 85:42–50, 1998). In the present study, the complete, unambiguous primary amino acid sequence of the peptide was obtained by a combination of both N-terminal sequencing of purified peptide and the complete sequence deduced from the structural gene harbored by plasmid I
4
. Data revealed that this peptide of 44 residues has an amino acid sequence similar to that described for pediocins AcH and PA-1, produced by different
Pediococcus acidilactici
strains and 100% identical. Coagulin and pediocin differed only by a single amino acid at their C terminus. Analysis of the genetic determinants revealed the presence, on the pI
4
DNA, of the entire 3.5-kb operon of four genes described for pediocin AcH and PA-1 production. No extended homology was observed between pSMB74 from
P. acidilactici
and pI
4
when analyzing the regions upstream and downstream of the operon. An oppositely oriented gene immediately dowstream of the bacteriocin operon specifies a 474-amino-acid protein which shows homology to Mob-Pre (plasmid recombination enzyme) proteins encoded by several small plasmids extracted from gram-positive bacteria. This is the first report of a pediocin-like peptide appearing naturally in a non-lactic acid bacterium genus.
Physiological Study of
Lactobacillus delbrueckii
subsp.
bulgaricus
Strains in a Novel Chemically Defined Medium
Authors: Chervaux Christian , Ehrlich S. Dusko , Maguin Emmanuelle 
Published: July 2002

ABSTRACT

We developed a chemically defined medium called milieu proche du lait (MPL), in which 22
Lactobacillus delbrueckii
subsp.
bulgaricus
(
L. bulgaricus
) strains exhibited growth rates ranging from 0.55 to 1 h
−1
. MPL can also be used for cultivation of other lactobacilli and
Streptococcus thermophilus
. The growth characteristics of
L. bulgaricus
in MPL containing different carbon sources were determined, including an initial characterization of the phosphotransferase system transporters involved. For the 22 tested strains, growth on lactose was faster than on glucose, mannose, and fructose. Lactose concentrations below 0.4% were limiting for growth. We isolated 2-deoxyglucose-resistant mutants from strains CNRZ397 and ATCC 11842. CNRZ397-derived mutants were all deficient for glucose, fructose, and mannose utilization, indicating that these three sugars are probably transported via a unique mannose-specific-enzyme-II-like transporter. In contrast, mutants of ATCC 11842 exhibited diverse phenotypes, suggesting that multiple transporters may exist in that strain. We also developed a protein labeling method and verified that exopolysaccharide production and phage infection can occur in MPL. The MPL medium should thus be useful in conducting physiological studies of
L. bulgaricus
and other lactic acid bacteria under well controlled nutritional conditions.
A Tetrodotoxin-Producing
Vibrio
Strain, LM-1, from the Puffer Fish
Fugu vermicularis radiatus
Authors: Lee Myoung-Ja , Jeong Dong-Youn , Kim Woo-Seong , Kim Hyun-Dae , Kim Cheorl-Ho , Park Won-Whan , Park Yong-Ha , Kim Kyung-Sam , Kim Hyung-Min , Kim Dong-Soo 
Published: July 2002

ABSTRACT

Identification of tetrodotoxin (TTX) and its derivatives produced from a
Vibrio
strain in the intestine of the puffer fish
Fugu vermicularis radiatus
was performed by thin-layer chromatography, electrophoresis, high-performance liquid chromatography, and gas chromatography-mass spectrometry, together with a mouse bioassay for toxicity. It was demonstrated that the isolated bacterium produced TTX, 4-epi-TTX, and anhTTX during cultivation, suggesting that
Vibrio
strains are responsible for the toxification of the puffer fish.
Microbiological Transformation of Enrofloxacin by the Fungus
Mucor ramannianus
Authors: Parshikov Igor A. , Freeman James P. , Lay Jackson O. , Beger Richard D. , Williams Anna J. , Sutherland John B. 
Published: July 2002

ABSTRACT

Enrofloxacin metabolism by
Mucor ramannianus
was investigated as a model for the biotransformation of veterinary fluoroquinolones. Cultures grown in sucrose-peptone broth were dosed with enrofloxacin. After 21 days, 22% of the enrofloxacin remained. Three metabolites were identified: enrofloxacin
N
-oxide (62% of the total absorbance),
N
-acetylciprofloxacin (8.0%), and desethylene-enrofloxacin (3.5%).
Overexpression of Protein Disulfide Isomerase DsbC Stabilizes Multiple-Disulfide-Bonded Recombinant Protein Produced and Transported to the Periplasm in
Escherichia coli
Authors: Kurokawa Yoichi , Yanagi Hideki , Yura Takashi 
Published: July 2002

ABSTRACT

Dsb proteins (DsbA, DsbB, DsbC, and DsbD) catalyze formation and isomerization of protein disulfide bonds in the periplasm of
Escherichia coli
. By using a set of Dsb coexpression plasmids constructed recently, we analyzed the effects of Dsb overexpression on production of horseradish peroxidase (HRP) isozyme C that contains complex disulfide bonds and tends to aggregate when produced in
E. coli
. When transported to the periplasm, HRP was unstable but was markedly stabilized upon simultaneous overexpression of the set of Dsb proteins (DsbABCD). Whereas total HRP production increased severalfold upon overexpression of at least disulfide-bonded isomerase DsbC, maximum transport of HRP to the periplasm seemed to require overexpression of all DsbABCD proteins, suggesting that excess Dsb proteins exert synergistic effects in assisting folding and transport of HRP. Periplasmic production of HRP also increased when calcium, thought to play an essential role in folding of nascent HRP polypeptide, was added to the medium with or without Dsb overexpression. These results suggest that Dsb proteins and calcium play distinct roles in periplasmic production of HRP, presumably through facilitating correct folding. The present Dsb expression plasmids should be useful in assessing and dissecting periplasmic production of proteins that contain multiple disulfide bonds in
E. coli
.
Development of a Combined Selection and Enrichment PCR Procedure for
Clostridium botulinum
Types B, E, and F and Its Use To Determine Prevalence in Fecal Samples from Slaughtered Pigs
Authors: Dahlenborg Maria , Borch Elisabeth , Rådström Peter 
Published: July 2002

ABSTRACT

A specific and sensitive combined selection and enrichment PCR procedure was developed for the detection of
Clostridium botulinum
types B, E, and F in fecal samples from slaughtered pigs. Two enrichment PCR assays, using the DNA polymerase
rTth,
were constructed. One assay was specific for the type B neurotoxin gene, and the other assay was specific for the type E and F neurotoxin genes. Based on examination of 29 strains of
C. botulinum
, 16 strains of other
Clostridium
spp., and 48 non-
Clostridium
strains, it was concluded that the two PCR assays detect
C. botulinum
types B, E, and F specifically. Sample preparation prior to the PCR was based on heat treatment of feces homogenate at 70°C for 10 min, enrichment in tryptone-peptone-glucose-yeast extract broth at 30°C for 18 h, and DNA extraction. The detection limits after sample preparation were established as being 10 spores per g of fecal sample for nonproteolytic type B, and 3.0 × 10
3
spores per g of fecal sample for type E and nonproteolytic type F with a detection probability of 95%. Seventy-eight pig fecal samples collected from slaughter houses were analyzed according to the combined selection and enrichment PCR procedure, and 62% were found to be PCR positive with respect to the type B neurotoxin gene. No samples were positive regarding the type E and F neurotoxin genes, indicating a prevalence of less than 1.3%. Thirty-four (71%) of the positive fecal samples had a spore load of less than 4 spores per g. Statistical analysis showed that both rearing conditions (outdoors and indoors) and seasonal variation (summer and winter) had significant effects on the prevalence of
C. botulinum
type B, whereas the effects of geographical location (southern and central Sweden) were less significant.
Concentrations of Copper Thought To Be Toxic to
Escherichia coli
Can Induce the Viable but Nonculturable Condition
Authors: Grey Brian , Steck Todd R. 
Published: July 2002

ABSTRACT

We have determined that concentrations of copper considered to be toxic can induce a fraction of a population of
Escherichia coli
to enter the viable but nonculturable (VBNC) condition. Copper-induced VBNC cells could be resuscitated for up to 2 weeks after entering the VBNC state.
Isolation from Agricultural Soil and Characterization of a
Sphingomonas
sp. Able To Mineralize the Phenylurea Herbicide Isoproturon
Authors: Sørensen Sebastian R. , Ronen Zeev , Aamand Jens 
Published: July 2002

ABSTRACT

A soil bacterium (designated strain SRS2) able to metabolize the phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was isolated from a previously IPU-treated agricultural soil. Based on a partial analysis of the 16S rRNA gene and the cellular fatty acids, the strain was identified as a
Sphingomonas
sp. within the α-subdivision of the proteobacteria. Strain SRS2 was able to mineralize IPU when provided as a source of carbon, nitrogen, and energy. Supplementing the medium with a mixture of amino acids considerably enhanced IPU mineralization. Mineralization of IPU was accompanied by transient accumulation of the metabolites 3-(4-isopropylphenyl)-1-methylurea, 3-(4-isopropylphenyl)-urea, and 4-isopropyl-aniline identified by high-performance liquid chromatography analysis, thus indicating a metabolic pathway initiated by two successive N-demethylations, followed by cleavage of the urea side chain and finally by mineralization of the phenyl structure. Strain SRS2 also transformed the dimethylurea-substituted herbicides diuron and chlorotoluron, giving rise to as-yet-unidentified products. In addition, no degradation of the methoxy-methylurea-substituted herbicide linuron was observed. This report is the first characterization of a pure bacterial culture able to mineralize IPU.
Characterization of Acetic Acid Bacteria in Traditional Acetic Acid Fermentation of Rice Vinegar (Komesu) and Unpolished Rice Vinegar (Kurosu) Produced in Japan
Authors: Nanda Kumiko , Taniguchi Mariko , Ujike Satoshi , Ishihara Nobuhiro , Mori Hirotaka , Ono Hisayo , Murooka Yoshikatsu 
Published: July 2002

ABSTRACT

Bacterial strains were isolated from samples of Japanese rice vinegar (komesu) and unpolished rice vinegar (kurosu) fermented by the traditional static method. Fermentations have never been inoculated with a pure culture since they were started in 1907. A total of 178 isolates were divided into groups A and B on the basis of enterobacterial repetitive intergenic consensus-PCR and random amplified polymorphic DNA fingerprinting analyses. The 16S ribosomal DNA sequences of strains belonging to each group showed similarities of more than 99% with
Acetobacter pasteurianus
. Group A strains overwhelmingly dominated all stages of fermentation of both types of vinegar. Our results indicate that appropriate strains of acetic acid bacteria have spontaneously established almost pure cultures during nearly a century of komesu and kurosu fermentation.
Chromatic Adaptation in Marine
Synechococcus
Strains
Authors: Palenik Brian 
Published: July 2002

ABSTRACT

Characterization of two genetically distinct groups of marine
Synechococcus
sp. strains shows that one, but not the other, increases its phycourobilin/phycoerythrobilin chromophore ratio when growing in blue light. This ability of at least some marine
Synechococcus
strains to chromatically adapt may help explain their greater abundance in particular ocean environments than cyanobacteria of the genus
Prochlorococcus
.