bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wound healing after mulesing and other options for controlling breech flystrike in Merino lambs: observations on gross and microscopic wound healing
Authors: Lepherd ML , Canfield PJ , Hunt GB , Thomson PC , Bosward KL 
Published: January 2011

Background  The mulesing procedure is the main procedure used to control breech flystrike of sheep in Australia, but other permanent methods of altering breech conformation are currently being investigated and wound healing is an important component of that comparative assessment.Objective  To qualitatively assess the gross and microscopic tissue damage and wound healing that occurs in the immediate post‐treatment period after mulesing, intradermal‐cetrimide treatment and clip application.Method  The study group of 30 mulesed, 30 cetrimide‐treated, 30 control and 10 clip‐treated sheep were humanely killed at six time points during the 3–47 days post treatment. Treatment sites and wound beds were examined grossly and microscopically.Results  Mulesing wounds healed rapidly in a predictable manner, producing long linear scars on either side of the breech and tail by 32–47 days post treatment. Although the time course for healing post cetrimide‐treatment was similar to that for mulesing, complications occurred and included inadequate wound healing because of persistence of adherent necrotic tissue, poor skin tightening around the tail, and patchy or deep penetration of the cetrimide resulting in necrosis of adjacent skin and deeper structures. The clips resulted in skin tightening around the ventrolateral breech and tail, although the formation of skin tags and clip slippage were of concern in some sheep.Conclusion  Wounds healed rapidly after mulesing with minimal complications. The intradermal‐cetrimide treatment appeared to produce imperfect and sometimes delayed wound healing compared with mulesing. The clips resulted in comparable wound healing to mulesing, but further field trials are required to assess their effectiveness in flystrike prevention.
Streptococcus mitis: walking the line between commensalism and pathogenesis
Authors: Mitchell J. 
Published: January 2011

Summary Streptococcus mitis is a viridans streptococcus and a normal commensal of the human oropharynx. However, S. mitis can escape from this niche and cause a variety of infectious complications including infective endocarditis, bacteraemia and septicaemia. It uses a variety of strategies to effectively colonize the human oropharynx. These include expression of adhesins, immunoglobulin A proteases and toxins, and modulation of the host immune system. These various colonization factors allow S. mitis to compete for space and nutrients in the face of its more pathogenic oropharyngeal microbial neighbours. However, it is likely that in vulnerable immune‐compromised patients S. mitis will use the same colonization and immune modulation factors as virulence factors promoting its opportunistic pathogenesis. The recent publication of a complete genome sequence for S. mitis strain B6 will allow researchers to thoroughly investigate which genes are involved in S. mitis host colonization and pathogenesis. Moreover, it will help to give insight into where S. mitis fits in the complicated oral microbiome. This review will discuss the current knowledge of S. mitis factors involved in host colonization, their potential role in virulence and what needs to be done to fully understand how a an oral commensal successfully transitions to a virulent pathogen.
Comparative
In Vitro
Activities of the Novel Antibacterial Finafloxacin against Selected Gram-Positive and Gram-Negative Bacteria Tested in Mueller-Hinton Broth and Synthetic Urine
Authors: Dalhoff Axel , Stubbings Will , Schubert Sabine 
Published: January 2011

ABSTRACT
Kill kinetics and MICs of finafloxacin and ciprofloxacin against 34 strains with defined resistance mechanisms grown in cation-adjusted Mueller-Hinton broth (CAMHB) at pH values of 7.2 and 5.8 and in synthetic urine at pH 5.8 were determined. In general, finafloxacin gained activity at low pH values in CAMHB and remained almost unchanged in artificial urine. Ciprofloxacin MICs increased and bactericidal activity decreased strain dependently in acidic CAMHB and particularly in artificial urine.
Cross-Resistance to Lincosamides, Streptogramins A, and Pleuromutilins Due to the
lsa
(C) Gene in
Streptococcus agalactiae
UCN70
Authors: Malbruny Brigitte , Werno Anja M. , Murdoch David R. , Leclercq Roland , Cattoir Vincent 
Published: January 2011

ABSTRACT

Streptococcus agalactiae
UCN70, isolated from a vaginal swab obtained in New Zealand, is resistant to lincosamides and streptogramins A (LS
A
phenotype) and also to tiamulin (a pleuromutilin). By whole-genome sequencing, we identified a 5,224-bp chromosomal extra-element that comprised a 1,479-bp open reading frame coding for an ABC protein (492 amino acids) 45% identical to Lsa(A), a protein related to intrinsic LS
A
resistance in
Enterococcus faecalis
. Expression of this novel gene, named
lsa
(C), in
S. agalactiae
BM132 after cloning led to an increase in MICs of lincomycin (0.06 to 4 μg/ml), clindamycin (0.03 to 2 μg/ml), dalfopristin (2 to >32 μg/ml), and tiamulin (0.12 to 32 μg/ml), whereas no change in MICs of erythromycin (0.06 μg/ml), azithromycin (0.03 μg/ml), spiramycin (0.25 μg/ml), telithromycin (0.03 μg/ml), and quinupristin (8 μg/ml) was observed. The phenotype was renamed the LS
A
P phenotype on the basis of cross-resistance to
l
incosamides,
s
treptogramins
A
, and
p
leuromutilins. This gene was also identified in similar genetic environments in 17 other
S. agalactiae
clinical isolates from New Zealand exhibiting the same LS
A
P phenotype, whereas it was absent in susceptible
S. agalactiae
strains. Interestingly, this extra-element was bracketed by a 7-bp duplication of a target site (ATTAGAA), suggesting that this structure was likely a mobile genetic element. In conclusion, we identified a novel gene,
lsa
(C), responsible for the acquired LS
A
P resistance phenotype in
S. agalactiae
. Dissection of the biochemical basis of resistance, as well as demonstration of
in vitro
mobilization of
lsa
(C), remains to be performed.
Experimental Phage Therapy in TreatingKlebsiella pneumoniae-Mediated Liver Abscesses and Bacteremia in Mice
Authors: Hung Chih-Hsin , Kuo Chih-Feng , Wang Chiou-Huey , Wu Ching-Ming , Tsao Nina 
Published: January 2011

ABSTRACTIntragastric inoculation of mice withKlebsiella pneumoniaecan cause liver abscesses, necrosis of liver tissues, and bacteremia. A newly isolated phage (φNK5) with lytic activity forK. pneumoniaewas used to treatK. pneumoniaeinfection in an intragastric model. Both intraperitoneal and intragastric administration of a single dose of φNK5 lower than 2 × 108PFU at 30 min afterK. pneumoniaeinfection was able to protect mice from death in a dose-dependent manner, but the efficacy achieved with a low dose of φNK5 by intragastric treatment provided the more significant protection. Phage φNK5 administered as late as 24 h afterK. pneumoniaeinoculation was still protective, while intraperitoneal treatment with phage was more efficient than intragastric treatment as a result of the dissemination of bacteria into the circulation at 24 h postinfection. Surveys of bacterial counts for mice treated with φNK5 by the intraperitoneal route revealed that the bacteria were eliminated effectively from both blood and liver tissue.K. pneumoniae-induced liver injury, such as liver necrosis, as well as blood levels of aspartate aminotransferase and alanine aminotransferase and inflammatory cytokine production, was significantly inhibited by φNK5 treatment. These data suggest that a low dose of φNK5 is a potential therapeutic agent forK. pneumoniae-induced liver infection.
Time-Kill Activity of the Streptogramin NXL 103 against Gram-Positive and -Negative Bacteria
Authors: Pankuch Glenn A. , Lin Gengrong , Clark Catherine , Appelbaum Peter C. 
Published: January 2011

ABSTRACTAgainst 33 Gram-positive and -negative bacteria, NXL 103 MICs were 0.03 to 1 μg/ml. NXL 103 was bactericidal by 12 h at 2 × MIC against all 5 pneumococci and at 2 × MIC after 24 h against all 5 group A and B β-hemolytic streptococci. NXL 103 was bactericidal against all 8Haemophilus influenzaestrains at 2× MIC and all 5Moraxella catarrhalisstrains at 4× MIC after 24 h but was mainly bacteriostatic against 5 methicillin-resistantStaphylococcus aureusstrains. After the exposure of one strain of each species to NXL 103 for 10 daily subcultures, the MICs remained within ±1 dilution.
In VitroCharacterization of GS-8374, a Novel Phosphonate-Containing Inhibitor of HIV-1 Protease with a Favorable Resistance Profile
Authors: Callebaut Christian , Stray Kirsten , Tsai Luong , Williams Matt , Yang Zheng-Yu , Cannizzaro Carina , Leavitt Stephanie A. , Liu Xiaohong , Wang Kelly , Murray Bernard P. , Mulato Andrew , Hatada Marcos , Priskich Tina , Parkin Neil , Swaminathan Swami , Lee William , He Gong-Xin , Xu Lianhong , Cihlar Tomas 
Published: January 2011

ABSTRACTGS-8374 is a novel bis-tetrahydrofuran HIV-1 protease (PR) inhibitor (PI) with a unique diethylphosphonate moiety. It was selected from a series of analogs containing various di(alkyl)phosphonate substitutions connected via a linker to theparaposition of a P-1 phenyl ring. GS-8374 inhibits HIV-1 PR with high potency (Ki= 8.1 pM) and with no known effect on host proteases. Kinetic and thermodynamic analysis of GS-8374 binding to PR demonstrated an extremely slow off rate for the inhibitor and favorable contributions of both the enthalpic and entropic components to the total free binding energy. GS-8374 showed potent antiretroviral activity in T-cell lines, primary CD4+T cells (50% effective concentration [EC50] = 3.4 to 11.5 nM), and macrophages (EC50= 25.5 nM) and exhibited low cytotoxicity in multiple human cell types. The antiviral potency of GS-8374 was only moderately affected by human serum protein binding, and its combination with multiple approved antiretrovirals showed synergistic effects. When it was tested in a PhenoSense assay against a panel of 24 patient-derived viruses with high-level PI resistance, GS-8374 showed lower mean EC50s and lower fold resistance than any of the clinically approved PIs. Similar to other PIs,in vitrohepatic microsomal metabolism of GS-8374 was efficiently blocked by ritonavir, suggesting a potential for effective pharmacokinetic boostingin vivo. In summary, results from this broadin vitropharmacological profiling indicate that GS-8374 is a promising candidate to be further assessed as a new antiretroviral agent with potential for clinical efficacy in both treatment-naïve and -experienced patients.
Primary Human Colonic Myofibroblasts Are Resistant toClostridium difficileToxin A-Induced, but Not Toxin B-Induced, Cell Death
Authors: Mullan N. , Hughes K. R. , Mahida Y. R. 
Published: January 2011

ABSTRACTColonic inflammation inClostridium difficileinfection is mediated by released toxins A and B. We investigated responses toC. difficiletoxins A and B by isolated primary human colonic myofibroblasts, which represent a distinct subpopulation of mucosal cells that are normally located below the intestinal epithelium. Following incubation with either purified toxin A or B, there was a change in myofibroblast morphology to stellate cells with processes that were immunoreactive for alpha-smooth muscle actin. Most of the myofibroblasts remained viable, with persistence of stellate morphology, despite exposure to high concentrations (up to 10 μg/ml) of toxin A for 72 h. In contrast, a majority of the toxin B-exposed myofibroblasts lost their processes prior to cell death over 24 to 72 h. At low concentrations, toxin A provided protection against toxin B-induced cell death. Within 4 h, myofibroblasts exposed to either toxin A or toxin B lost expression of the nonglucosylated form of Rac1, and there was also a loss of the active form of RhoA. Despite preexposure to high concentrations of toxin A for 3 h, colonic myofibroblasts were able to recover their morphology and proliferative capacity during prolonged culture in medium. However, toxin B-preexposed myofibroblasts were not able to recover. In conclusion, primary human colonic mucosal myofibroblasts are resistant to toxin A (but not toxin B)-induced cell death. Responses by colonic myofibroblasts may play an important role in mucosal protection, repair, and regeneration in colitis due toC. difficileinfection.
Beta Interferon Suppresses the Development of Experimental Cerebral Malaria
Authors: Morrell Craig N. , Srivastava Kalyan , Swaim AnneMarie , Lee M. Teresa , Chen Jun , Nagineni Chandrashakaharam , Hooks John J. , Detrick Barbara 
Published: January 2011

ABSTRACTCerebral malaria (CM) is a major complication ofPlasmodium falciparuminfection, particularly in children. The pathogenesis of cerebral malaria involves parasitized red blood cell (RBC)-mediated vascular inflammation, immune stimulation, loss of blood-brain barrier integrity, and obstruction of cerebral capillaries. Therefore, blunting vascular inflammation and immune cell recruitment is crucial in limiting the disease course. Beta interferon (IFN-β) has been used in the treatment of diseases, such as multiple sclerosis (MS) but has not yet been explored in the treatment of CM. Therefore, we sought to determine whether IFN-β also limits disease progression in experimental cerebral malaria (ECM).Plasmodium berghei-infected mice treated with IFN-β died later and showed increased survival, with improved blood-brain barrier function, compared to infected mice. IFN-β did not alter systemic parasitemia. However, we identified multiple action sites that were modified by IFN-β administration.P. bergheiinfection resulted in increased expression of chemokine (C-X-C motif) ligand 9 (CXCL9) in brain vascular endothelial cells that attract T cells to the brain, as well as increased T-cell chemokine (C-X-C motif) receptor 3 (CXCR3) expression. The infection also increased the cellular content of intercellular adhesion molecule 1 (ICAM-1), a molecule important for attachment of parasitized RBCs to the endothelial cell. In this article, we report that IFN-β treatment leads to reduction of CXCL9 and ICAM-1 in the brain, reduction of T-cell CXCR3 expression, and downregulation of serum tumor necrosis factor alpha (TNF-α). In addition, IFN-β-treatedP. berghei-infected mice also had fewer brain T-cell infiltrates, further demonstrating its protective effects. Hence, IFN-β has important anti-inflammatory properties that ameliorate the severity of ECM and prolong mouse survival.
Staphylococcal Alpha-Toxin Is a Strong Inducer of Interleukin-17 in Humans
Authors: Niebuhr Margarete , Gathmann Merle , Scharonow Helena , Mamerow Diana , Mommert Susanne , Balaji Hari , Werfel Thomas 
Published: January 2011

ABSTRACTPatients with atopic dermatitis (AD) are frequently colonized withStaphylococcus aureus, with one-third of isolates producing alpha-toxin. Moreover,S. aureuscolonization is positively correlated with the severity of eczema. Interleukin-17A (IL-17A) has gained attention in diseases associated with chronic skin infections. The aim of this study was to investigate the effects of sublytic alpha-toxin concentrations on IL-17A production. Sublytic alpha-toxin concentrations strongly induced IL-17A in peripheral blood mononuclear cells (PBMCs), isolated CD4+T cells, polarized Th17 cells, and Th17 clones from reactive atopy patch test lesions and blood from AD patients. Alpha-toxin induced IL-17A directly in T cells. The effect of alpha-toxin was further amplified by upregulation of IL-1 in monocytes. In conclusion, higher levels of IL-17A secretion induced by alpha-toxin in the skin partially explain how colonization withS. aureuscan contribute to chronic skin inflammation.
The Atherogenic BacteriumPorphyromonas gingivalisEvades Circulating Phagocytes by Adhering to Erythrocytes
Authors: Belstrøm Daniel , Holmstrup Palle , Damgaard Christian , Borch Tanja S. , Skjødt Mikkel-Ole , Bendtzen Klaus , Nielsen Claus H. 
Published: January 2011

ABSTRACTA relationship between periodontitis and coronary heart disease has been investigated intensively. A pathogenic role for the oral bacteriumPorphyromonas gingivalishas been suggested for both diseases. We examined whether complement activation byP. gingivalisstrain ATCC 33277 allows the bacterium to adhere to human red blood cells (RBCs) and thereby evade attack by circulating phagocytes. On incubation with normal human serum, theP. gingivalisstrain efficiently fixed complement component 3 (C3). Incubation of bacteria with washed whole blood cells suspended in autologous serum resulted in a dose- and time-dependent adherence to RBCs. The adherence required functionally intact complement receptor 1 (CR1; also called CD35) on the RBCs and significantly inhibited the uptake ofP. gingivalisby neutrophils and B cells within 1 min of incubation (by 64% and 51%, respectively) and that by monocytes after between 15 min and 30 min of incubation (by 66% and 53%, respectively). The attachment of C3b/iC3b to bacterium-bearing RBCs decreased progressively after 15 min, indicating that conversion of C3 fragments into C3dg occurred, decreasing the affinity for CR1 on RBCs. We propose thatP. gingivalisexploits RBCs as a transport vehicle, rendering it inaccessible to attack by phagocytes, and by doing so plays a role in the development of systemic diseases.
Chlamydial Infection Increases Gonococcal Colonization in a Novel Murine Coinfection Model
Authors: Vonck Rachel A. , Darville T. , O'Connell C. M. , Jerse Ann E. 
Published: January 2011

ABSTRACTGenital tract infections caused byNeisseria gonorrhoeaeandChlamydia trachomatisserovars D to K occur at high incidence in many areas of the world. Despite high rates of coinfection with these pathogens, investigations of host-parasite interactions have focused on each pathogen individually. We describe here a coinfection model in which female BALB/c mice were first infected with the mouseChlamydiaspeciesC. muridarumand then inoculated withN. gonorrhoeaefollowing treatment with water-soluble 17β-estradiol to promote long-term gonococcal infection. Viable gonococci and chlamydiae were recovered for an average of 8 to 10 days, and diplococci and chlamydial inclusions were observed in lower genital tract tissue by immunohistochemical staining. Estradiol treatment reduced proinflammatory cytokine and chemokine levels in chlamydia-infected mice; however, coinfected mice had a higher percentage of vaginal neutrophils compared to mice infected with either pathogen alone. We detected no difference in pathogen-specific antibody levels due to coinfection. Interestingly, significantly more gonococci were recovered from coinfected mice compared to mice infected withN. gonorrhoeaealone. We found no evidence thatC. muridarumincreases gonococcal adherence to, or invasion of, immortalized murine epithelial cells. However, increased vaginal concentrations of inflammatory mediators macrophage inflammatory protein 2 and tumor necrosis factor alpha were detected inC. muridarum-infected mice prior to inoculation withN. gonorrhoeaeconcurrently with the downregulation of cathelicidin-related antimicrobial peptide and secretory leukocyte peptidase inhibitor genes. We conclude that female mice can be successfully infected with bothC. muridarumandN. gonorrhoeaeand that chlamydia-induced alterations in host innate responses may enhance gonococcal infection.
Cpa, the Outer Membrane Protease ofCronobacter sakazakii, Activates Plasminogen and Mediates Resistance to Serum Bactericidal Activity
Authors: Franco A. A. , Kothary M. H. , Gopinath G. , Jarvis K. G. , Grim C. J. , Hu L. , Datta A. R. , McCardell B. A. , Tall B. D. 
Published: January 2011

ABSTRACTCronobacterspp. are emerging neonatal pathogens in humans, associated with outbreaks of meningitis and sepsis. To cause disease, they must survive in blood and invade the central nervous system by penetrating the blood-brain barrier.C. sakazakiiBAA-894 possesses an ∼131-kb plasmid (pESA3) that encodes an outer membrane protease (Cpa) that has significant identity to proteins that belong to the Pla subfamily of omptins. Members of this subfamily of proteins degrade a number of serum proteins, including circulating complement, providing protection from the complement-dependent serum killing. Moreover, proteins of the Pla subfamily can cause uncontrolled plasmin activity by converting plasminogen to plasmin and inactivating the plasmin inhibitor α2-antiplasmin (α2-AP). These reactions enhance the spread and invasion of bacteria in the host. In this study, we found that an isogeniccpamutant showed reduced resistance to serum in comparison to its parentC. sakazakiiBAA-894 strain. Overexpression of Cpa inC. sakazakiiorEscherichia coliDH5α showed that Cpa proteolytically cleaved complement components C3, C3a, and C4b. Furthermore, a strain ofC. sakazakiioverexpressing Cpa caused a rapid activation of plasminogen and inactivation of α2-AP. These results strongly suggest that Cpa may be an important virulence factor involved in serum resistance, as well as in the spread and invasion ofC. sakazakii.
Genome-Scale Identification of Resistance Functions in Pseudomonas aeruginosa Using Tn-seq
Authors: Gallagher Larry A. , Shendure Jay , Manoil Colin 
Published: January 2011

ABSTRACT

We describe a deep-sequencing procedure for tracking large numbers of transposon mutants of
Pseudomonas aeruginosa
. The procedure employs a new Tn-seq methodology based on the generation and amplification of single-strand circles carrying transposon junction sequences (the Tn-seq circle method), a method which can be used with virtually any transposon. The procedure reliably identified more than 100,000 transposon insertions in a single experiment, providing near-saturation coverage of the genome. To test the effectiveness of the procedure for mutant identification, we screened for mutations reducing intrinsic resistance to the aminoglycoside antibiotic tobramycin. Intrinsic tobramycin resistance had been previously analyzed at genome scale using mutant-by-mutant screening and thus provided a benchmark for evaluating the new method. The new Tn-seq procedure identified 117 tobramycin resistance genes, the majority of which were then verified with individual mutants. The group of genes with the strongest mutant phenotypes included nearly all (13 of 14) of those with strong mutant phenotypes identified in the previous screening, as well as a nearly equal number of new genes. The results thus show the effectiveness of the Tn-seq method in defining the genetic basis of a complex resistance trait of
P. aeruginosa
and indicate that it can be used to analyze a variety of growth-related processes.

IMPORTANCE
Research progress in microbiology is technology limited in the sense that the analytical methods available dictate how questions are experimentally addressed and, to some extent, what questions are asked. This report describes a new transposon tracking procedure for defining the genetic basis of growth-related processes in
Pseudomonas aeruginosa
, an important bacterial pathogen. The method employs next-generation sequencing to monitor the makeup of mutant populations (Tn-seq) and has several potential advantages over other Tn-seq methodologies. The new method was validated through the analysis of a clinically relevant antibiotic resistance trait.