bluuebunny/crossref_metadata_2025_split huggingface dataset:
Outbreak of Colistin-Resistant, Carbapenem-Resistant
Klebsiella pneumoniae
in Metropolitan Detroit, Michigan
Authors: Marchaim Dror , Chopra Teena , Pogue Jason M. , Perez Federico , Hujer Andrea M. , Rudin Susan , Endimiani Andrea , Navon-Venezia Shiri , Hothi Jatinder , Slim Jessica , Blunden Christopher , Shango Maryann , Lephart Paul R. , Salimnia Hossein , Reid Deborah , Moshos Judy , Hafeez Wasif , Bheemreddy Suchitha , Chen Ting-Yi , Dhar Sorabh , Bonomo Robert A. , Kaye Keith S. 
Published: November 2010

ABSTRACT

Carbapenem-resistant
Klebsiella pneumoniae
has spread worldwide and throughout the United States. Colistin is used extensively to treat infections with this organism. We describe a cluster of colistin-resistant, carbapenem-resistant
K. pneumoniae
infection cases involving three institutions in Detroit, MI. A cluster of five cases of colistin-resistant, carbapenem-resistant
K. pneumoniae
was identified at Detroit Medical Center (DMC) from 27 July to 22 August 2009. Epidemiologic data were collected, and transmission opportunities were analyzed. Isolates were genotyped by using pulsed-field gel electrophoresis and repetitive extragenic palindromic PCR. Data regarding the use of colistin were obtained from pharmacy records. The index case of colistin-resistant, carbapenem-resistant
K. pneumoniae
was followed 20 days later by four additional cases occurring in a 6-day interval. All of the patients, at some point, had stayed at one particular institution. The mean number of opportunities for transmission between patients was 2.3 ± 0.5, and each patient had at least one opportunity for transmission with one of the other patients. Compared to 60 colistin-susceptible, carbapenem-resistant
K. pneumoniae
controls isolated in the previous year at DMC, case patients were significantly older (
P
= 0.05) and the carbapenem-resistant
K. pneumoniae
organisms isolated from them displayed much higher MICs to imipenem (
P
< 0.001). Colistin use was not enhanced in the months preceding the outbreak. Genotyping revealed two closely related clones. This report of a colistin-resistant, carbapenem-resistant
K. pneumoniae
outbreak is strongly linked to patient-to-patient transmission. Controlling the spread and novel emergence of bacteria with this phenotype is of paramount importance.
Candida
Bloodstream Infections: Comparison of Species Distributions and Antifungal Resistance Patterns in Community-Onset and Nosocomial Isolates in the SENTRY Antimicrobial Surveillance Program, 2008-2009
Authors: Pfaller Michael A. , Moet Gary J. , Messer Shawn A. , Jones Ronald N. , Castanheira Mariana 
Published: November 2010

ABSTRACT

Community-onset (CO) candidemia, defined as a positive blood culture taken at or within 2 days of hospital admission, represents a distinct clinical entity associated with substantial morbidity and mortality. Reference MIC results from the SENTRY Antimicrobial Surveillance Program (2008-2009) were analyzed to compare the antifungal resistance patterns and species distributions from patients with CO and nosocomial bloodstream infections (BSI) in 79 medical centers. Among 1,354 episodes of BSI, 494 (36.5%) were classified as CO and 860 (63.5%) as nosocomial in origin. More than 95% of the isolates from both BSI types were contributed by
Candida albicans
(48.4%),
C. glabrata
(18.2%),
C. parapsilosis
(17.1%),
C. tropicalis
(10.6%), and
C. krusei
(2.0%).
C. albicans
was more common in CO BSI (51.0%) than nosocomial BSI (46.9%), whereas
C. parapsilosis
and
C. krusei
were more common in nosocomial BSIs (18.1 and 2.7%, respectively) than in CO BSIs (15.4 and 0.8%, respectively).
C. glabrata
and
C. tropicalis
were comparable in both CO (18.4 and 10.5%, respectively) and nosocomial (18.1 and 10.6%, respectively) episodes. Resistance to azoles (fluconazole, posaconazole, and voriconazole) and echinocandins (anidulafungin, caspofungin, and micafungin) was uncommon (<5%) in CO BSI using recently established Clinical and Laboratory Standards Institute breakpoint criteria. Resistance to echinocandins (anidulafungin [3.8%], caspofungin [5.1%], and micafungin [3.2%]) and azoles (fluconazole [7.7%], posaconazole [5.1%], and voriconazole [6.4%]) was most prevalent among nosocomial BSI isolates of
C. glabrata
. CO candidemia is not uncommon and appears to be increasing worldwide due to changing health care practices. Although resistance to the azoles and echinocandins remains uncommon among CO isolates, we demonstrate the emergence of nosocomial occurrences of
C. glabrata
expressing resistance to both monitored classes of antifungal agents.
In VitroAntiretroviral Properties of S/GSK1349572, a Next-Generation HIV Integrase Inhibitor
Authors: Kobayashi Masanori , Yoshinaga Tomokazu , Seki Takahiro , Wakasa-Morimoto Chiaki , Brown Kevin W. , Ferris Robert , Foster Scott A. , Hazen Richard J. , Miki Shigeru , Suyama-Kagitani Akemi , Kawauchi-Miki Shinobu , Taishi Teruhiko , Kawasuji Takashi , Johns Brian A. , Underwood Mark R. , Garvey Edward P. , Sato Akihiko , Fujiwara Tamio 
Published: November 2010

ABSTRACTS/GSK1349572 is a next-generation HIV integrase (IN) inhibitor designed to deliver potent antiviral activity with a low-milligram once-daily dose requiring no pharmacokinetic (PK) booster. In addition, S/GSK1349572 demonstrates activity against clinically relevant IN mutant viruses and has potential for a high genetic barrier to resistance. S/GSK1349572 is a two-metal-binding HIV integrase strand transfer inhibitor whose mechanism of action was established throughin vitrointegrase enzyme assays, resistance passage experiments, activity against viral strains resistant to other classes of anti-HIV agents, and mechanistic cellular assays. In a variety of cellular antiviral assays, S/GSK1349572 inhibited HIV replication with low-nanomolar or subnanomolar potency and with a selectivity index of 9,400. The protein-adjusted half-maximal effective concentration (PA-EC50) extrapolated to 100% human serum was 38 nM. When virus was passaged in the presence of S/GSK1349572, highly resistant mutants were not selected, but mutations that effected a low fold change (FC) in the EC50(up to 4.1 fold) were identified in the vicinity of the integrase active site. S/GSK1349572 demonstrated activity against site-directed molecular clones containing the raltegravir-resistant signature mutations Y143R, Q148K, N155H, and G140S/Q148H (FCs, 1.4, 1.1, 1.2, and 2.6, respectively), while these mutants led to a high FC in the EC50of raltegravir (11- to >130-fold). Either additive or synergistic effects were observed when S/GSK1349572 was tested in combination with representative approved antiretroviral agents; no antagonistic effects were seen. These findings demonstrate that S/GSK1349572 would be classified as a next-generation drug in the integrase inhibitor class, with a resistance profile markedly different from that of first-generation integrase inhibitors.
Mutation Analysis of the
Mycobacterium leprae folP1
Gene and Dapsone Resistance
Authors: Nakata Noboru , Kai Masanori , Makino Masahiko 
Published: November 2010

ABSTRACT

Diaminodiphenylsulfone (dapsone) has long been used as a first-line drug worldwide for the treatment of leprosy. Diagnosis for dapsone resistance of
Mycobacterium leprae
by DNA tests would be of great clinical value, but the relationship between the nucleotide substitutions and susceptibility to dapsone must be clarified before use. In this study, we constructed recombinant strains of cultivable
Mycobacterium smegmatis
carrying the
M. leprae folP1
gene with or without a point mutation, disrupting their own
folP
gene on the chromosome. Dapsone susceptibilities of the recombinant bacteria were measured to examine influence of the mutations. Dapsone MICs for most of the strains with mutations at codon 53 or 55 of
M. leprae folP1
were 2 to 16 times as high as the MIC for the strain with the wild-type
folP1
sequence, but mutations that changed Thr to Ser at codon 53 showed somewhat lower MIC values than the wild-type sequence. Strains with mutations at codon 48 or 54 showed levels of susceptibility to dapsone comparable to the susceptibility of the strain with the wild-type sequence. This study confirmed that point mutations at codon 53 or 55 of the
M. leprae folP1
gene result in dapsone resistance.
Impact of P-Glycoprotein Inhibition and Lipopolysaccharide Administration on Blood-Brain Barrier Transport of Colistin in Mice
Authors: Jin Liang , Li Jian , Nation Roger L. , Nicolazzo Joseph A. 
Published: November 2010

ABSTRACT

The aim of this study was to investigate the factors limiting the blood-brain barrier (BBB) transport of colistin in healthy mice and to assess the impact of systemic inflammation on the transport of this antibiotic across the BBB. Colistin sulfate (40 mg/kg) was administered subcutaneously to Swiss outbred mice as single and multiple doses to determine any relationship between brain uptake and plasma concentrations of colistin. To assess the effect of P-glycoprotein (P-gp) on BBB transport, colistin sulfate (5 mg/kg) was concomitantly administered intravenously with PSC833 or GF120918 (10 mg/kg). Systemic inflammation was induced by three intraperitoneal injections of lipopolysaccharide (LPS; 3 mg/kg), and BBB transport of colistin was subsequently measured following subcutaneous administration and by an
in situ
brain perfusion. The brain uptake of colistin was low following single and multiple subcutaneous doses, with brain-to-plasma concentration ratios ranging between 0.021 and 0.037, and this was not significantly enhanced by coadministration of GF120918 or PSC833 (
P
> 0.05). LPS significantly increased the brain uptake of subcutaneously administered colistin with area under the brain concentration time curve (AUC
brain
) values of 11.7 ± 2.7 μg·h/g and 4.0 ± 0.3 μg·h/g for LPS- and saline-treated mice, respectively (mean ± standard deviation). Similarly,
in situ
perfusion of colistin led to higher antibiotic brain concentrations in LPS-treated animals than in saline-treated animals, with colistin brain-to-perfusate concentration ratios of 0.019 ± 0.001 and 0.014 ± 0.001, respectively. This study demonstrates that the BBB transport of colistin is negligible in healthy mice; however, brain concentrations of colistin can be significantly enhanced during systemic inflammation, as might be observed in infected patients.
Influence of Storage Conditions on the Growth of
Pseudomonas
Species in Refrigerated Raw Milk
Authors: De Jonghe Valerie , Coorevits An , Van Hoorde Koenraad , Messens Winy , Van Landschoot Anita , De Vos Paul , Heyndrickx Marc 
Published: November 2010

ABSTRACT

The refrigerated storage of raw milk throughout the dairy chain prior to heat treatment creates selective conditions for growth of psychrotolerant bacteria. These bacteria, mainly belonging to the genus
Pseudomonas
, are capable of producing thermoresistant extracellular proteases and lipases, which can cause spoilage and structural defects in pasteurized and ultra-high-temperature-treated milk (products). To map the influence of refrigerated storage on the growth of these pseudomonads, milk samples were taken after the first milking turn and incubated laboratory scale at temperatures simulating optimal and suboptimal preprocessing storage conditions. The outgrowth of
Pseudomonas
members was monitored over time by means of cultivation-independent denaturing gradient gel electrophoresis (DGGE). Isolates were identified by a polyphasic approach. These incubations revealed that outgrowth of
Pseudomonas
members occurred from the beginning of the dairy chain (farm tank) under both optimal and suboptimal storage conditions. An even greater risk for outgrowth, as indicated by a vast increase of about 2 log CFU per ml raw milk, existed downstream in the chain, especially when raw milk was stored under suboptimal conditions. This difference in
Pseudomonas
outgrowth between optimal and suboptimal storage was already statistically significant within the farm tank. The predominant taxa were identified as
Pseudomonas gessardii
,
Pseudomonas gessardii
-like,
Pseudomonas fluorescens
-like,
Pseudomonas lundensis
,
Pseudomonas fragi
, and
Pseudomonas fragi
-like. Those taxa show an important spoilage potential as determined on elective media for proteolysis and lipolysis.
Biodiversity of
Clostridium botulinum
Type E Associated with a Large Outbreak of Botulism in Wildlife from Lake Erie and Lake Ontario
Authors: Hannett George E. , Stone Ward B. , Davis Stephen W. , Wroblewski Danielle 
Published: November 2010

ABSTRACT

The genetic relatedness of
Clostridium botulinum
type E isolates associated with an outbreak of wildlife botulism was studied using random amplification of polymorphic DNA (RAPD). Specimens were collected from November 2000 to December 2008 during a large outbreak of botulism affecting birds and fish living in and around Lake Erie and Lake Ontario. In our present study, a total of 355 wildlife samples were tested for the presence of botulinum toxin and/or organisms. Type E botulinum toxin was detected in 110 samples from birds, 12 samples from fish, and 2 samples from mammals. Sediment samples from Lake Erie were also examined for the presence of
C. botulinum
. Fifteen of 17 sediment samples were positive for the presence of
C. botulinum
type E. Eighty-one
C. botulinum
isolates were obtained from plants, animals, and sediments; of these isolates, 44
C. botulinum
isolates produced type E toxin, as determined by mouse bioassay, while the remaining 37 isolates were not toxic for mice. All toxin-producing isolates were typed by RAPD; that analysis showed 12 different RAPD types and multiple subtypes. Our study thus demonstrates that multiple genetically distinct strains of
C. botulinum
were involved in the present outbreak of wildlife botulism. We found that
C. botulinum
type E is present in the sediments of Lake Erie and that a large range of bird and fish species is affected.
MVE1
, Encoding the Velvet Gene Product Homolog in
Mycosphaerella graminicola
, Is Associated with Aerial Mycelium Formation, Melanin Biosynthesis, Hyphal Swelling, and Light Signaling
Authors: Choi Yoon-E , Goodwin Stephen B. 
Published: November 2010

ABSTRACT

The ascomycete fungus
Mycosphaerella graminicola
is an important pathogen of wheat that causes
Septoria tritici
blotch. Despite the serious impact of
M. graminicola
on wheat production worldwide, knowledge about its molecular biology is limited. The velvet gene,
veA
, is one of the key regulators of diverse cellular processes, including development and secondary metabolism in many fungi. However, the species analyzed to date are not related to the
Dothideomycetes
, the largest class of plant-pathogenic fungi, and the function of
veA
in this group is not known. To test the hypothesis that the velvet gene has similar functions in the
Dothideomycetes
, a
veA
-homologous gene,
MVE1
, was identified and gene deletion mutations (Δ
mve1
) were generated in
M. graminicola
. All of the
MVE1
mutants exhibited consistent pleiotropic phenotypes, indicating the involvement of
MVE1
in multiple signaling pathways. Δ
mve1
strains displayed albino phenotypes with significant reductions in melanin biosynthesis and less production of aerial mycelia on agar plates. In liquid culture, Δ
mve1
strains showed abnormal hyphal swelling, which was suppressed completely by osmotic stress or lower temperature. In addition,
MVE1
gene deletion led to hypersensitivity to shaking, reduced hydrophobicity, and blindness to light-dependent stimulation of aerial mycelium production. However, pathogenicity was not altered in Δ
mve1
strains. Therefore, the light-signaling pathway associated with
MVE1
does not appear to be important for
Septoria tritici
blotch disease. Our data suggest that the
MVE1
gene plays crucial roles in multiple key signaling pathways and is associated with light signaling in
M. graminicola
.
Molecular Description and Industrial Potential of Tn
6098
Conjugative Transfer Conferring Alpha-Galactoside Metabolism in
Lactococcus lactis
Authors: Machielsen Ronnie , Siezen Roland J. , van Hijum Sacha A. F. T. , van Hylckama Vlieg Johan E. T. 
Published: November 2010

ABSTRACT

A novel 51-kb conjugative transposon of
Lactococcus lactis
, designated Tn
6098
, encoding the capacity to utilize α-galactosides such as raffinose and stachyose, was identified and characterized. Alpha-galactosides are a dominant carbon source in many plant-derived foods. Most dairy lactococcus strains are unable to use α-galactosides as a growth substrate, yet many of these strains are known to have beneficial industrial traits. Conjugal transfer of Tn
6098
was demonstrated from the plant-derived donor strain
L. lactis
KF147 to the recipient
L. lactis
NZ4501, a derivative of the dairy model strain
L. lactis
MG1363. The integration of Tn
6098
into the genome of the recipient strain was confirmed by Illumina sequencing of the transconjugant
L. lactis
NIZO3921. The molecular structure of the integration site was confirmed by a PCR product spanning the insertion site. A 15-bp direct repeat sequence (TTATACCATAATTAC) is present on either side of Tn
6098
in the chromosome of
L. lactis
KF147. One copy of this sequence is also present in the
L. lactis
MG1363 chromosome and represents the sole integration site. Phenotypic characterization of all strains showed that the transconjugant has not only acquired the ability to grow well in soy milk, a substrate rich in α-galactosides, but also has retained the flavor-forming capabilities of the recipient strain
L. lactis
MG1363. This study demonstrates how (induced) conjugation can be used to exploit the beneficial industrial traits of industrial dairy lactic acid bacteria in fermentation of plant-derived substrates.
Use of RmInt1, a Group IIB Intron Lacking the Intron-Encoded Protein Endonuclease Domain, in Gene Targeting
Authors: García-Rodríguez Fernando M. , Barrientos-Durán Antonio , Díaz-Prado Vanessa , Fernández-López Manuel , Toro Nicolás 
Published: November 2010

ABSTRACT

The group IIA intron Ll.LtrB from
Lactococcus lactis
and the group IIB intron EcI5 from
Escherichia coli
have intron-encoded proteins (IEP) with a DNA-binding domain (D) and an endonuclease domain (En). Both have been successfully retargeted to invade target DNAs other than their wild-type target sites. RmInt1, a subclass IIB3/D intron with an IEP lacking D and En domains, is highly active in retrohoming in its host,
Sinorhizobium meliloti
. We found that RmInt1 was also mobile in
E. coli
and that retrohoming in this heterologous host depended on temperature, being more efficient at 28°C than at 37°C. Furthermore, we programmed RmInt1 to recognize target sites other than its wild-type site. These retargeted introns efficiently and specifically retrohome into a recipient plasmid target site or a target site present as a single copy in the chromosome, generating a mutation in the targeted gene. Our results extend the range of group II introns available for gene targeting.
Immunization with
Salmonella enterica
Serovar Typhimurium-Derived Outer Membrane Vesicles Delivering the Pneumococcal Protein PspA Confers Protection against Challenge with
Streptococcus pneumoniae
Authors: Muralinath Maneesha , Kuehn Meta J. , Roland Kenneth L. , Curtiss Roy 
Published: November 2010

ABSTRACT

Gram-negative bacteria produce outer membrane vesicles (OMVs) that serve a variety of functions related to survival and pathogenicity. Periplasmic and outer membrane proteins are naturally captured during vesicle formation. This property has been exploited as a method to derive immunogenic vesicle preparations for use as vaccines. In this work, we constructed a
Salmonella enterica
serovar Typhimurium strain that synthesized a derivative of the pneumococcal protein PspA engineered to be secreted into the periplasmic space. Vesicles isolated from this strain contained PspA in the lumen. Mice intranasally immunized with the vesicle preparation developed serum antibody responses against vesicle components that included PspA and
Salmonella
-derived lipopolysaccharide and outer membrane proteins, while no detectable responses developed in mice immunized with an equivalent dose of purified PspA. Mucosal IgA responses developed against the
Salmonella
components, while the response to PspA was less apparent in most mice. Mice immunized with the vesicle preparation were completely protected against a 10× 50% lethal dose (LD
50
) challenge of
Streptococcus pneumoniae
and significantly protected against a 200× LD
50
challenge, while control mice immunized with purified PspA or empty vesicles were not protected. These results establish that vesicles can be used to mucosally deliver an antigen from a Gram-positive organism and induce a protective immune response.
Novel Members of the Cra Regulon Involved in Carbon Metabolism in
Escherichia coli
Authors: Shimada Tomohiro , Yamamoto Kaneyoshi , Ishihama Akira 
Published: November 2010

ABSTRACT

Cra (
c
atabolite
r
epressor
a
ctivator) is a global regulator of the genes for carbon metabolism in
Escherichia coli
. To gain insights into the regulatory roles of Cra, attempts were made to identify the whole set of regulation targets using an improved genomic SELEX (systematic evolution of ligands by exponential enrichment) system. Surprisingly, a total of 164 binding sites were identified for Cra, 144 (88%) of which were newly identified. The majority of known targets were included in the SELEX chip pattern. The promoters examined by the
lacZ
reporter assay
in vivo
were all regulated by Cra. These two lines of evidence indicate that a total of as many as 178 promoters are under the control of Cra. The majority of Cra targets are the genes coding for the enzymes involved in central carbon metabolism, covering all the genes for the enzymes involved in glycolysis and metabolism downstream of glycolysis, including the tricarboxylic acid (TCA) cycle and aerobic respiration. Taken together, we propose that Cra plays a key role in balancing the levels of the enzymes for carbon metabolism.
Cell Biology of the Trypanosome Genome
Authors: Daniels Jan-Peter , Gull Keith , Wickstead Bill 
Published: November 2010

SUMMARYTrypanosomes are a group of protozoan eukaryotes, many of which are major parasites of humans and livestock. The genomes of trypanosomes and their modes of gene expression differ in several important aspects from those of other eukaryotic model organisms. Protein-coding genes are organized in large directional gene clusters on a genome-wide scale, and their polycistronic transcription is not generally regulated at initiation. Transcripts from these polycistrons are processed by globaltrans-splicing of pre-mRNA. Furthermore, in African trypanosomes, some protein-coding genes are transcribed by a multifunctional RNA polymerase I from a specialized extranucleolar compartment. The primary DNA sequence of the trypanosome genomes and their cellular organization have usually been treated as separate entities. However, it is becoming increasingly clear that in order to understand how a genome functions in a living cell, we will need to unravel how the one-dimensional genomic sequence and itstrans-acting factors are arranged in the three-dimensional space of the eukaryotic nucleus. Understanding this cell biology of the genome will be crucial if we are to elucidate the genetic control mechanisms of parasitism. Here, we integrate the concepts of nuclear architecture, deduced largely from studies of yeast and mammalian nuclei, with recent developments in our knowledge of the trypanosome genome, gene expression, and nuclear organization. We also compare this nuclear organization to those in other systems in order to shed light on the evolution of nuclear architecture in eukaryotes.