bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Pediocin-Producing
Lactobacillus plantarum
Strain Inhibits
Listeria monocytogenes
in a Multispecies Cheese Surface Microbial Ripening Consortium
Authors: Loessner Melanie , Guenther Susanne , Steffan Sandra , Scherer Siegfried 
Published: March 2003

ABSTRACT

The growth of
Listeria monocytogenes
WSLC 1364, originating from a cheese-borne outbreak, was examined in the presence and in the absence of a pediocin AcH-producing
Lactobacillus plantarum
strain on red smear cheese. Nearly complete inhibition was observed at 10
2
CFU of
L. monocytogenes
per ml of salt brine solution, while contamination with
Listeria
mutants resistant to pediocin resulted in high cell counts of the pathogen on the cheese surface. The inhibition was due to pediocin AcH added together with the
L. plantarum
culture to the brine solution but not to bacteriocin production in situ on cheese. Pediocin resistance developed in vitro at different but high frequencies in all 12
L. monocytogenes
strains investigated, and a resistant mutant remained stable in a microbial surface ripening consortium over a 4-month production process in the absence of selection pressure. In conclusion, the addition of a
L. plantarum
culture is a potent measure for combating
Listeria
in a contaminated production line, but because of the potential development of resistance, it should not be used continuously over a long time in a production line.
An Improved Enrichment Broth for Isolation of
Escherichia coli
O157, with Specific Reference to Starved Cells, from Radish Sprouts
Authors: Sata Shin , Fujisawa Tomohiko , Osawa Ro , Iguchi Atsushi , Yamai Shiro , Shimada Toshio 
Published: March 2003

ABSTRACT

An enrichment broth was developed for the efficient isolation of
Escherichia coli
O157 from radish sprouts. The broth was buffered peptone water containing 0.5% sodium thioglycolate (STG-BPW), which was designed to allow growth of
E. coli
O157 in starved and unstarved states. However, this medium suppressed the growth of non-carbohydrate-fermenting obligate aerobes whose colonial appearance on sorbitol MacConkey agar containing cefixime and tellurite (CT-SMAC) resembled that of
E. coli
O157. Both starved and unstarved cells of
E. coli
O157 experimentally inoculated into radish sprouts were successfully recovered with STG-BPW enrichment in all cases, most of which showed marked disappearance of
E. coli
O157-like colonies on CT-SMAC.
Heterologous Expression of the
Saccharomyces cerevisiae PGU1
Gene in
Schizosaccharomyces pombe
Yields an Enzyme with More Desirable Properties for the Food Industry
Authors: Sieiro C. , Poza M. , Vilanova M. , Villa T. G. 
Published: March 2003

ABSTRACT

The
Saccharomyces cerevisiae PGU1
gene was successfully expressed in
Schizosaccharomyces pombe
. The optimum pH and temperature for the recombinant enzyme were 5 and 40°C, respectively, these being around 0.5 U higher and 5°C lower than those shown by the native enzyme. The

K
m

value was about fourfold higher than that of the
S. cerevisiae
enzyme. The recombinant endopolygalacturonase was more efficient in reducing the viscosity of polygalacturonic acid and was also more stable at different pHs and temperatures than the native enzyme.
Anaerobic Mineralization of Quaternary Carbon Atoms: Isolation of Denitrifying Bacteria on Pivalic Acid (2,2-Dimethylpropionic Acid)
Authors: Probian Christina , Wülfing Annika , Harder Jens 
Published: March 2003

ABSTRACT

The degradability of pivalic acid was established by the isolation of several facultative denitrifying strains belonging to
Zoogloea resiniphila
, to
Thauera
and
Herbaspirillum
, and to
Comamonadaceae
, related to [
Aquaspirillum
] and
Acidovorax
, and of a nitrate-reducing bacterium affiliated with
Moraxella osloensis
. Pivalic acid was completely mineralized to carbon dioxide. The catabolic pathways may involve an oxidation to dimethylmalonate or a carbon skeleton rearrangement, a putative 2,2-dimethylpropionyl coenzyme A mutase.
Biodegradation of the Nitramine Explosive CL-20
Authors: Trott Sandra , Nishino Shirley F. , Hawari Jalal , Spain Jim C. 
Published: March 2003

ABSTRACT

The cyclic nitramine explosive CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) was examined in soil microcosms to determine whether it is biodegradable. CL-20 was incubated with a variety of soils. The explosive disappeared in all microcosms except the controls in which microbial activity had been inhibited. CL-20 was degraded most rapidly in garden soil. After 2 days of incubation, about 80% of the initial CL-20 had disappeared. A CL-20-degrading bacterial strain,
Agrobacterium
sp. strain JS71, was isolated from enrichment cultures containing garden soil as an inoculum, succinate as a carbon source, and CL-20 as a nitrogen source. Growth experiments revealed that strain JS71 used 3 mol of nitrogen per mol of CL-20.
Invasive
Streptococcus iniae
Infections Outside North America
Authors: Lau Susanna K. P. , Woo Patrick C. Y. , Tse Herman , Leung Kit-Wah , Wong Samson S. Y. , Yuen Kwok-Yung 
Published: March 2003

ABSTRACT

Streptococcus iniae
, a fish pathogen causing infections in aquaculture farms worldwide, has only been reported to cause human infections in North America. In this article, we report the first two cases of invasive
S. iniae
infections in two Chinese patients outside North America. While the first patient presented with bacteremic cellulitis, which is the most common presentation in previous cases, the second patient represents the first recognized case of
S. iniae
osteomyelitis. Both
S. iniae
strains isolated from the two patients were either misidentified or unidentified by three commercial systems and were only identified by 16S rRNA gene sequencing. Since no currently available commercial system for bacterial identification includes
S. iniae
in its database, 16S rRNA gene sequencing is the most practical and reliable method to identify the bacterium at the moment. In contrast to the distinct genetic profile described previously in clinical isolates from Canada, the present two isolates and a clinical isolate from a Canadian patient were found to be genetically unrelated, as demonstrated by pulsed-field gel electrophoresis. Morphologically, colonies of both isolates were also larger, more beta-hemolytic and mucoid, which differ from the usual morphotype described for
S. iniae
. Owing to their habit of cooking and eating fresh fish, the Asian population is strongly associated with
S. iniae
infections. As a result of the difficulty in making microbiological diagnosis in patients with cellulitis and the problem of identification in most clinical microbiology laboratories, the prevalence of
S. iniae
infections, especially in the Asian population, may have been under-estimated.
Conventional Methods versus 16S Ribosomal DNA Sequencing for Identification of Nontuberculous Mycobacteria: Cost Analysis
Authors: Cook Victoria J. , Turenne Christine Y. , Wolfe Joyce , Pauls Ryan , Kabani Amin 
Published: March 2003

ABSTRACT
The clinical profile of nontuberculous mycobacteria (NTM) has been raised by the human immunodeficiency virus and AIDS pandemic. Different laboratory techniques, often molecular based, are available to facilitate the rapid and accurate identification of NTM. The expense of these advanced techniques has been questioned. At the National Reference Center for Mycobacteriology and the Health Sciences Center, University of Manitoba, in Winnipeg, Canada, we performed a direct cost analysis of laboratory techniques for commercial DNA probe-negative (Gen-Probe, Inc., San Diego, Calif.), difficult-to-identify NTM. We compared the costs associated with conventional phenotypic methodology (biochemical testing, pigment production, growth, and colony characteristics) and genotypic methodology (16S ribosomal DNA [rDNA] sequence-based identification). We revealed a higher cost per sample with conventional methods, and this cost varied with organism characteristics: $80.93 for slowly growing, biochemically active NTM; $173.23 for slowly growing, biochemically inert NTM; and $129.40 for rapidly growing NTM. The cost per sample using 16S rDNA sequencing was $47.91 irrespective of organism characteristics, less than one-third of the expense associated with phenotypic identification of biochemically inert, slow growers. Starting with a pure culture, the turnaround time to species identification is 1 to 2 days for 16S rDNA sequencing compared to 2 to 6 weeks for biochemical testing. The accuracy of results comparing both methodologies is briefly discussed. 16S rDNA sequencing provides a cost-effective alternative in the identification of clinically relevant forms of probe-negative NTM. This concept is not only useful in mycobacteriology but also is highly applicable in other areas of clinical microbiology.
p24 Antigen Detection Assay Modified with a Booster Step for Diagnosis and Monitoring of Human Immunodeficiency Virus Type 1 Infection
Authors: Sutthent Ruengpung , Gaudart Narintorn , Chokpaibulkit Kulkanya , Tanliang Nattaya , Kanoksinsombath Chinda , Chaisilwatana Pongsakdi 
Published: March 2003

ABSTRACTWe modified a p24 antigen enzyme-linked immunosorbent assay as a method for diagnosis and monitoring of human immunodeficiency virus type 1 (HIV-1) subtype E infection. This modified assay is based on the use of preheated immune complex dissociation combined with a booster step using a regular Vironostika HIV-1 p24 antigen assay (bioMerieux) to decrease the lower limit of p24 antigen detection from 10 pg/ml (lower limit achievable when using a regular p24 antigen assay) to 0.5 pg/ml (100 virions/ml) by the new method. The correlation between the values obtained by the HIV-1 RNA (Amplicor HIV-1 Monitor) assay and the p24 antigen assay modified with a booster step antigen assay in 160 frozen plasma samples with known viral load and 80 blind fresh plasma samples by Spearman rank were 0.671 (R2= 0.450;P< 0.01) and 0.782 (R2= 0.612;P< 0.01). During antiretroviral treatment, the change of p24 antigen level at ≥0.5 log correlated well with the level of HIV-1 in plasma. In order to improve the early diagnosis of HIV-1 infection in 121 infants born to HIV-1-infected mothers, a heat-denatured plasma p24 antigen assay modified with a booster step was compared with DNA-PCR and HIV RNA (nucleic acid sequence-based amplification) assays. The sensitivity of the antigen test modified with a booster step was similar to that of the HIV-1 RNA (NASBA QL) assay and better than that of the DNA-PCR assay (100 versus 61.90%) for subjects 1 to 2 months old. The overall results from this study might renew interest in p24 antigen detection as an easily affordable alternative method for diagnosis of HIV-1 infection and monitoring of disease progression in developing countries.
Epidemiology of Tetracycline Resistance Determinants in
Shigella
spp. and Enteroinvasive
Escherichia coli
: Characterization and Dissemination of
tet
(A)-
1
Authors: Hartman Antoinette B. , Essiet Idongesit I. , Isenbarger Daniel W. , Lindler Luther E. 
Published: March 2003

ABSTRACT

To make a comprehensive study of tetracycline resistance determinant distribution in the genus
Shigella
, a collection of 577 clinical isolates of
Shigella
spp. and enteroinvasive
Escherichia coli
(EIEC) from a variety of geographical locations was screened to identify tetracycline-resistant strains. The 459 tetracycline-resistant isolates identified were then screened by PCR analysis to determine the distribution in these strains of tetracycline efflux resistance determinants belonging to classes A to E, G, and H that have been identified in gram-negative bacteria. Only classes A to D were represented in these strains. Although Tet B was the predominant determinant in all geographical locations, there were geographical and species differences in the distribution of resistance determinants. An allele of
tet
(A), designated
tet
(A)-
1
, was identified and sequenced, and the 8.6-kb plasmid containing determinant Tet A-1, designated pSSTA-1, was found to have homologies to portions of a
Salmonella enterica
cryptic plasmid and the broad-host-range resistance plasmid RSF1010. This allele and pSSTA-1 were used as epidemiological markers to monitor clonal and horizontal transmission of determinant Tet A-1. An analysis of serotype, distribution of tetracycline resistance determinants, and resistance profiles indicated that both clonal spread and horizontal transfer had contributed to the spread of specific tetracycline resistance determinants in these populations and demonstrated the use of these parameters as an epidemiological tool to follow the transmission of determinants and strains.
Serology and Genetics of the Flagellar Antigen ofEscherichia coliO157:H7a,7c
Authors: Ratiner Yuli A. , Salmenlinna Saara , Eklund Marjut , Keskimäki Markku , Siitonen Anja 
Published: March 2003

ABSTRACTAmongEscherichia colistrains of the O55:H7 serovar, which is considered the ancestor of Shiga toxin-producingE. coli(STEC) O157:H7, two subtypes, H7a,7b and H7a,7c (briefly, H7a,b and H7a,c, respectively), of the H7 flagellar antigen have been described previously [J. Wright and R. Villanueva, J. Hyg. (Camb.) 51:39-48, 1953; Y. A. Ratiner and V. A. Sinelnikova, Zh. Microbiol. Epidemiol. Immunobiol. 3:111-116, 1969). We have now studied 13 STEC O157:H7 strains and 1 O55:H7 strain that were epidemiologically unrelated, that originated from six countries on two continents, and that had different profiles when analyzed by multilocus enzyme electrophoresis, pulsed-field gel electrophoresis, and PCR forstxandeae. They were all found to possess the H7a,c flagellar antigen. Serum cross-absorption assays confirmed that their H antigens were indistinguishable from each other and from that ofE. coliO55:H7a,c but differed from the standard H7a,b antigen ofE. coliH test strain U5/41. It was shown by phage-mediated transduction that the flagellin genes for these two H-antigen subserotypes were alleles of theE. coli fliClocus. On the basis of the serological data obtained in this study and the molecular characteristics ofE. coli fliCH7alleles recently published, it is inferred that H7a,c and H7a,b are the main serological subtypes of the group ofE. coliH7 flagellins.
Epitope-Blocking Enzyme-Linked Immunosorbent Assays for the Detection of Serum Antibodies to West Nile Virus in Multiple Avian Species
Authors: Blitvich Bradley J. , Marlenee Nicole L. , Hall Roy A. , Calisher Charles H. , Bowen Richard A. , Roehrig John T. , Komar Nicholas , Langevin Stanley A. , Beaty Barry J. 
Published: March 2003

ABSTRACT
We report the development of epitope-blocking enzyme-linked immunosorbent assays (ELISAs) for the rapid detection of serum antibodies to West Nile virus (WNV) in taxonomically diverse North American avian species. A panel of flavivirus-specific monoclonal antibodies (MAbs) was tested in blocking assays with serum samples from WNV-infected chickens and crows. Selected MAbs were further tested against serum samples from birds that represented 16 species and 10 families. Serum samples were collected from birds infected with WNV or Saint Louis encephalitis virus (SLEV) and from noninfected control birds. Serum samples from SLEV-infected birds were included in these experiments because WNV and SLEV are closely related antigenically, are maintained in similar transmission cycles, and have overlapping geographic distributions. The ELISA that utilized MAb 3.1112G potentially discriminated between WNV and SLEV infections, as all serum samples from WNV-infected birds and none from SLEV-infected birds were positive in this assay. Assays with MAbs 2B2 and 6B6C-1 readily detected serum antibodies in all birds infected with WNV and SLEV, respectively, and in most birds infected with the other virus. Two other MAbs partially discriminated between infections with these two viruses. Serum samples from most WNV-infected birds but no SLEV-infected birds were positive with MAb 3.67G, while almost all serum samples from SLEV-infected birds but few from WNV-infected birds were positive with MAb 6B5A-5. The blocking assays reported here provide a rapid, reliable, and inexpensive diagnostic and surveillance technique to monitor WNV activity in multiple avian species.
Detection and Characterization of the Hemolysin Genes in
Aeromonas hydrophila
and
Aeromonas sobria
by Multiplex PCR
Authors: Wang Gehua , Clark Clifford G. , Liu Chenyi , Pucknell Chad , Munro Cindy K. , Kruk Tamara M. A. C. , Caldeira Richard , Woodward David L. , Rodgers Frank G. 
Published: March 2003

ABSTRACT

A multiplex PCR assay was designed to amplify the
Aeromonas hydrophila
and
A. veronii
bv. sobria hemolysin and aerolysin genes. The assay was evaluated by using 121 clinical isolates and 7 reference strains of
Aeromonas
spp., and these were divided into five genotypes on the basis of the results of the multiplex PCR. The five genotypes were characterized as type 1 for those carrying the
ahh1
gene only (36% of isolates), type 2 for those carrying the
asa1
gene only (8.5% of isolates), type 3 for those carrying both the
ahh1
and the
asa1
genes (4% of isolates), type 4 for those carrying the
ahh1
gene and the A. hydrophila aerA (aerolysin) gene (37.5% of isolates), and type 5 for those in which no hemolysin genes were detected (14% of isolates). The most common single hemolysin gene carried among all the
Aeromonas
isolates examined was
ahh1
, with 99 of 128 (77%) of isolates testing positive for this gene either alone or in combination with other hemolysin genes. Phenotypic expression of toxins was evaluated in a Vero cell culture cytotoxicity assay. These results indicated that there is a statistically significant correlation between the cytotoxin titers and the hemolysin genotype. Isolates belonging to genotype 4 (carrying both the
ahh1
gene and the aerolysin and hemolysin
aerA
genes) expressed higher cytotoxin titers than isolates of the other genotypes (
P
< 0.001). These isolates were more cytotoxic in cell culture and may have greater clinical significance.
Use of Listeriolysin O and Internalin A in a Seroepidemiological Study of Listeriosis in Swiss Dairy Cows
Authors: Boerlin Patrick , Boerlin-Petzold Franziska , Jemmi Thomas 
Published: March 2003

ABSTRACTRecombinant listeriolysin O and internalin A were used as antigens in an enzyme-linked immunosorbent assay (ELISA) for the specific detection of anti-Listeria monocytogenesantibodies in cattle. The results showed sensitivities and specificities of 82 and 92%, respectively, for the listeriolysin O ELISA, and 100 and 90%, respectively, for the internalin A ELISA, respectively. The test may be useful for the confirmation of listeria-related abortions and mastitis but does not seem to be indicated for use in the diagnosis of listeria-related encephalitis in cattle. A representative sample of 1,652 serum samples from the healthy dairy cattle population in Switzerland was tested by both ELISAs. The results showed that 11% of the healthy dairy cows in Switzerland simultaneously presented antibodies toward listeriolysin O and internalin A, and 48% of the farms had one or several animals simultaneously positive by assays with both antigens. Multivariable analysis at the farm level confirmed that feeding of silage represents a significant risk factor for a positive listeria serology. Detailed analysis identified corn silage but not grass silage as the major factor in this association. Cattle breed and hygiene on the farm were also identified as significant factors associated with the serological status of farms. In conclusion, the results of the study show that internalin A is a promising new antigen for use in listeria serology and that specific anti-L. monocytogenesantibodies are found in a significant proportion of healthy dairy cows in Switzerland.
Comparison of Broth Microdilution, E Test, and Agar Dilution Methods for Antibiotic Susceptibility Testing of
Campylobacter jejuni
and
Campylobacter coli
Authors: Luber Petra , Bartelt Edda , Genschow Elke , Wagner Jutta , Hahn Helmut 
Published: March 2003

ABSTRACT

A standardized broth microdilution method was compared to the E test and an agar dilution method for the antimicrobial susceptibility testing of
Campylobacter jejuni
and
C. coli
isolates. A group of 47 human clinical isolates, 37 isolates from retail poultry, and 29 isolates from living turkeys (total, 113 isolates) was included in the study. These encompassed 92
C. jejuni
and 21
C. coli
strains. The MICs of six antimicrobial agents were determined by the broth microdilution and E test methods, and the strains of human origin were additionally tested by the agar dilution method. In general, broth microdilution MICs agreed within 1 log
2
MIC increment with 90.0% of E test results and 78.7% of agar dilution test results. The agar dilution method gave much lower gentamicin MICs than the broth microdilution method, but the data were significantly (
P
< 0.01) correlated and there was 100% agreement in the sensitivities and specificities in the comparison of the tests. The broth microdilution method had the highest sensitivity for analysis of the susceptibilities of
Campylobacter
to nalidixic acid and trimethoprim-sulfamethoxazole. The MICs of ciprofloxacin and erythromycin complied numerically by all three methods. The classification of the results and the correlation of the data demonstrated a high degree of agreement. All methods were equally suitable for the testing of the sensitivity of
Campylobacter
to tetracycline. Thus, the broth microdilution method appears to be an easy and reliable method for determination of the MICs of antibiotics for
C. jejuni
and
C. coli
, and it may offer an interesting alternative to MIC determination by the agar dilution technique or the E test.
Detection and Identification of
Bartonella
Species Pathogenic for Humans by PCR Amplification Targeting the Riboflavin Synthase Gene (
ribC
)
Authors: Johnson G. , Ayers M. , McClure S. C. C. , Richardson S. E. , Tellier R. 
Published: March 2003

ABSTRACT

Several
Bartonella
species have now been implicated as human pathogens. The recovery of these fastidious organisms in the clinical microbiology laboratory remains difficult, and current methods are still relatively insensitive. Thus, the bartonellae are good candidates for detection by PCR. We have developed a PCR assay which uses a single primer pair targeting the riboflavin synthase gene (
ribC
) and detected six
Bartonella
species that have been implicated in human disease,
B. henselae
,
B. quintana
,
B. bacilliformis
,
B. clarridgeiae
,
B. elizabethae
, and
B. vinsonii
subsp.
berkhoffii.
Species identification is achieved simply by restriction enzyme digestion of the amplicon. This PCR assay appears to be specific for the
Bartonella
genus because it failed to amplify DNA from several other bacterial species.
Quantitative Microbiologic Models for Preterm Delivery
Authors: Onderdonk Andrew B. , Lee Mei-Ling , Lieberman Ellice , Delaney Mary L. , Tuomala Ruth E. 
Published: March 2003

ABSTRACT
Preterm delivery (PTD) is the leading cause of infant morbidity and mortality in the United States. An epidemiological association between PTD and various bacteria that are part of the vaginal microflora has been reported. No single bacterial species has been identified as being causally associated with PTD, suggesting a multifactorial etiology. Quantitative microbiologic cultures have been used previously to define normal vaginal microflora in a predictive model. These techniques have been applied to vaginal swab cultures from pregnant women in an effort to develop predictive microbiologic models for PTD. Logistic regression analysis with microbiologic information was performed for various risk groups, and the probability of a PTD was calculated for each subject. Four predictive models were generated by using the quantitative microbiologic data. The area under the curve (AUC) for the receiver operating curves ranged from 0.74 to 0.94, with confidence intervals (CI) ranging from 0.62 to 1. The model for the previous PTD risk group with the highest percentage of PTDs had an AUC of 0.91 (CI, 0.79 to 1). It may be possible to predict PTD by using microbiologic risk factors measured once the gestation period has reached the 20-week time point.