bluuebunny/crossref_metadata_2025 huggingface dataset:
Moxifloxacin (BAY12-8039), a New 8-Methoxyquinolone, Is Active in a Mouse Model of Tuberculosis
Authors: Miyazaki Eishi , Miyazaki Miki , Chen Jong Min , Chaisson Richard E. , Bishai William R.
Published: October 2018

Moxifloxacin (BAY12-8039) is a new 8-methoxyquinolone shown to be active againstMycobacterium tuberculosisin vitro. We tested moxifloxacin for activity in mice againstM. tuberculosisCSU93, a highly virulent, recently isolated clinical strain. The MIC of moxifloxacin for the CSU93 strain was 0.25 μg/ml. The serum moxifloxacin concentration after oral administration in mice peaked within 0.25 h, reaching 7.8 μg/ml with doses of 100 mg/kg of body weight; the maximum concentration and the analysis of the area under the concentration-time curve revealed dose dependency. When mice were infected with a sublethal inoculum of mycobacteria and then treated with moxifloxacin at 100 mg/kg per day for 8 weeks, the log10CFU counts in the organs of treated mice were significantly lower than those for the control group (0.6 ± 0.2 versus 5.6 ± 0.3 in the lungs and 1.5 ± 0.7 versus 4.9 ± 0.5 in the spleens, respectively;P< 0.001 in both organs). The effectiveness of moxifloxacin monotherapy was comparable to that seen in mice receiving isoniazid alone. Combination therapy with moxifloxacin plus isoniazid was superior to that with moxifloxacin or with isoniazid alone in reducing bacillary counts in the organs studied. Using a sensitive broth-passage subculture method, we demonstrated that 8 weeks of treatment with moxifloxacin (100 mg/kg per day) or with moxifloxacin plus isoniazid (100 mg/kg and 25 mg/kg, respectively, per day) sterilized the lungs in seven of eight and in eight of eight mice, respectively. Among surviving bacilli isolated from animals infected with a high-titer inoculum and treated for 7 weeks with low-dose moxifloxacin (20 mg/kg per day), breakthrough resistance to moxifloxacin was not observed. These results indicate that moxifloxacin is highly effective in reducingM. tuberculosisinfection in mice and has activity comparable to that of isoniazid. Combination therapy with moxifloxacin and isoniazid was highly effective, suggesting that moxifloxacin may be useful in multiple-drug regimens for human tuberculosis.
Penetration of Moxifloxacin into Peripheral Compartments in Humans
Authors: Müller Markus , Staß Heino , Brunner Martin , Möller Jan G. , Lackner Edith , Eichler Hans G.
Published: October 2018

To characterize the penetration of moxifloxacin (BAY 12-8039) into peripheral target sites, the present study aimed at measuring unbound moxifloxacin concentrations in the interstitial space fluid by means of microdialysis, an innovative clinical sampling technique. In addition, moxifloxacin concentrations were measured in cantharides-induced skin blisters, saliva, and capillary plasma and compared to total- and free-drug concentrations in venous plasma. For this purpose, 12 healthy volunteers received moxifloxacin in an open randomized crossover fashion either as a single oral dose of 400 mg or as a single intravenous infusion of 400 mg over 60 min. An almost-complete equilibration of the free unbound plasma fraction of moxifloxacin with the interstitial space fluid was observed, with mean area under the concentration-time curve (AUC)
interstitial fluid
/AUC
total-plasma
ratios ranging from 0.38 to 0.55 and mean AUC
interstitial fluid
/AUC
free-plasma
ratios ranging from 0.81 to 0.86. The skin blister concentration/plasma concentration ratio reached values above 1.5 after 24 h, indicating a preferential penetration of moxifloxacin into inflamed lesions. The moxifloxacin concentrations in saliva and capillary blood were similar to the corresponding levels in plasma. Our data show that moxifloxacin concentrations attained in the interstitial space fluid in humans and in skin blister fluid following single doses of 400 mg exceed the values for the MIC at which 90% of isolates are inhibited for most clinically relevant bacterial strains, notably including penicillin-resistant
Streptococcus pneumoniae
. These findings support the use of moxifloxacin for the treatment of soft tissue and respiratory tract infections in humans.
Inhibition of Human Immunodeficiency Virus Type 1 Replication in Acutely and Chronically Infected Cells by EM2487, a Novel Substance Produced by aStreptomycesSpecies
Authors: Baba Masanori , Okamoto Mika , Takeuchi Hitoshi
Published: October 2018

In a search for effective HIV-1 transcription inhibitors, we have evaluated more than 75,000 compounds for their inhibitory effects on Tat-induced human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR)-driven reporter gene expression and found that EM2487, a novel small-molecule substance produced by aStreptomycesspecies, is a potent and selective inhibitor of HIV-1 replication in both acutely and chronically infected cells. Its 50% effective concentration for acute HIV-1 infection was 0.27 μM in peripheral blood mononuclear cells (PBMCs), while the 50% cytotoxic concentration for mock-infected PBMCs was 13.3 μM. EM2487 proved inhibitory to a variety of HIV-1 strains and HIV-2 in acutely infected T-cell lines (MOLT-4 and MT-4). The compound could suppress tumor necrosis factor alpha (TNF-α)-induced HIV-1 production in latently infected cells (OM-10.1 and ACH-2) as well as constitutive viral production in chronically infected cells (MOLT-4/IIIBand U937/IIIB) without showing any cytotoxicity. EM2487 did not affect early events of the HIV-1 replication cycle, as determined by proviral DNA synthesis in acutely infected MOLT-4 cells. In contrast, the compound selectively prevented viral mRNA synthesis in OM-10.1 cells, suggesting that HIV-1 inhibition occurs at the transcriptional level. Furthermore, EM2487 did not inhibit TNF-α-induced HIV-1 LTR-driven reporter gene expression but did inhibit that induced by Tat, irrespective of the presence or absence of the nuclear factor κB binding sites in the LTR. These results suggest that the mechanism of action is attributable in part to the inhibition of Tat function.
β-Lactamase Production in
Prevotella intermedia
,
Prevotella nigrescens
, and
Prevotella pallens
Genotypes and In Vitro Susceptibilities to Selected Antimicrobial Agents
Authors: Mättö Jaana , Asikainen Sirkka , Väisänen Marja-Liisa , Von Troil-Lindén Birgitta , Könönen Eija , Saarela Maria , Salminen Kari , Finegold Sydney M. , Jousimies-Somer Hannele
Published: October 2018

The present study investigated the β-lactamase production of 73
Prevotella intermedia
, 84
Prevotella nigrescens
, and 14
Prevotella pallens
isolates and their in vitro susceptibilities to six antimicrobial agents. The
P. intermedia
and
P. nigrescens
isolates were recovered from oral and extraoral samples obtained from subjects in two geographic locations from 1985 to 1995. The clonality of the β-lactamase-positive and β-lactamase-negative isolates and the clustering of the genotypes were studied by arbitrarily primed-PCR fingerprinting. β-Lactamase production was detected in 29% of
P. intermedia
isolates, 29% of
P. nigrescens
isolates, and 57% of
P. pallens
isolates. No difference in the frequencies of β-lactamase production by
P. intermedia
and
P. nigrescens
between isolates from oral and extraoral sites, between isolates obtained at different time periods, or between
P. intermedia
isolates from different geographic locations was observed. However, the
P. nigrescens
isolates from the United States were significantly more frequently (
P
= 0.015) β-lactamase positive than those from Finland. No association between the genotypes and β-lactamase production or between the genotypes and the sources of the isolates was found. The penicillin G MICs at which 90% of the isolates were inhibited were 8 μg/ml for
P. intermedia
, 8 μg/ml for
P. nigrescens
, and 16 μg/ml for
P. pallens
. For the β-lactamase-negative isolates, the corresponding values were 0.031, 0.031, and 0.125 μg/ml, and for the β-lactamase-positive isolates, the corresponding values were 16, 8, and 32 μg/ml. All isolates were susceptible to amoxicillin-clavulanate, cefoxitin, metronidazole, azithromycin, and trovafloxacin. The MICs of amoxicillin-clavulanate and cefoxitin were relatively higher for the β-lactamase-positive population than for the β-lactamase-negative population.
Reconstruction of an Active Integron Recombination Site after Integration of a Gene Cassette at a Secondary Site
Authors: Segal Heidi , Francia M. Victoria , Lobo Juan M. García , Elisha Gay
Published: October 2018

As the site of insertion of the
aadB
gene cassette on pRAY, from a clinical isolate of
Acinetobacter
, is almost identical to the preferred site on integrons, the composite 59-base element (59-BE) associated with this cassette is potentially recombinationally active. By using a conduction assay to quantitate site activity, the 59-BE was recognized by integrase with high frequency, indicating that the composite site is recombinationally active.
Synergy Testing of Vancomycin-Resistant
Enterococcus faecium
against Quinupristin-Dalfopristin in Combination with Other Antimicrobial Agents
Authors: Matsumura S. O. , Louie L. , Louie M. , Simor A. E.
Published: October 2018

Using checkerboard and time-kill assays, we evaluated the in vitro activity of quinupristin-dalfopristin (RP 59500) alone and in combination with five other antimicrobial agents against 12 clinical strains of vancomycin-resistant
Enterococcus faecium
(VREF). In time-kill studies, six VREF strains exhibited synergism with the combination of quinupristin-dalfopristin and doxycycline and three exhibited synergism with quinupristin-dalfopristin plus ampicillin-sulbactam. Combinations of quinupristin-dalfopristin with these and other agents warrant further clinical evaluation for the treatment of serious VREF infections.
Mutations in 23S rRNA in
Helicobacter pylori
Conferring Resistance to Erythromycin Do Not Always Confer Resistance to Clarithromycin
Authors: García-Arata M. Isabel , Baquero Fernando , de Rafael Luis , de Argila Carlos Martín , Gisbert Javier P. , Bermejo Fernando , Boixeda Daniel , Cantón Rafael
Published: October 2018

Mutations conferring resistance to erythromycin or clarithromycin in
Helicobacter pylori
were studied. Mutation A2142G was consistently associated with clarithromycin MIC of >256 μg/ml, whereas mutants carrying A2143G had MICs ranging from ≤0.016 to >256 μg/ml, suggesting that additional factors account for the observed multiple levels of resistance to clarithromycin.
Molecular and Biochemical Characterization of VEB-1, a Novel Class A Extended-Spectrum β-Lactamase Encoded by an
Escherichia coli
Integron Gene
Authors: Poirel Laurent , Naas Thierry , Guibert Michele , Chaibi El Bachir , Labia Roger , Nordmann Patrice
Published: October 2018

A clinical isolate,
Escherichia coli
MG-1, isolated from a 4-month-old Vietnamese orphan child, produced a β-lactamase conferring resistance to extended-spectrum cephalosporins and aztreonam. In a disk diffusion test, a typical synergistic effect between ceftazidime or aztreonam and clavulanic acid was observed along with an unusual synergy between cefoxitin and cefuroxime. The gene for VEB-1 (Vietnamese extended-spectrum β-lactamase) was cloned and expressed in
E. coli
JM109. The recombinant plasmid pRLT1 produced a β-lactamase with a pI of 5.35 and conferred high-level resistance to extended-spectrum (or oxyimino) cephalosporins and to aztreonam.
V
max
values for extended-spectrum cephalosporins were uncommonly high, while the affinity of the enzyme for ceftazidime and aztreonam was relatively low.
bla
VEB-1
showed significant homology at the DNA level with only
bla
PER-1
and
bla
PER-2
. Analysis of the deduced protein sequence showed that VEB-1 is a class A penicillinase having very low levels of homology with any other known β-lactamases. The highest percentage of amino acid identity was 38% with PER-1 or PER-2, two uncommon class A extended-spectrum enzymes. Exploration of the genetic environment of
bla
VEB-1
revealed the presence of gene cassette features, i.e., (i) a 59-base element associated with
bla
VEB-1
; (ii) a second 59-base element just upstream of
bla
VEB-1
, likely belonging to the
aacA1-orfG
gene cassette; (iii) two core sites (GTTRRRY) on both sides of
bla
VEB-1
; and (iv) a second antibiotic resistance gene 3′ of
bla
VEB-1
,
aadB. bla
VEB-1
may therefore be the first class A extended-spectrum β-lactamase that is part of a gene cassette, which itself is likely to be located on a class 1 integron, as sulfamide resistance may indicate. Furthermore,
bla
VEB-1
is encoded on a large (>100-kb) transferable plasmid found in a
Klebsiella pneumoniae
MG-2 isolated at the same time from the same patient, indicating a horizontal gene transfer.
8-Aminoquinolines Active against Blood Stage
Plasmodium falciparum
In Vitro Inhibit Hematin Polymerization
Authors: Vennerstrom Jonathan L. , Nuzum Edwin O. , Miller Robert E. , Dorn Arnulf , Gerena Lucia , Dande Prasad A. , Ellis William Y. , Ridley Robert G. , Milhous Wilbur K.
Published: October 2018

From the Walter Reed Army Institute of Research (WRAIR) inventory, thirteen 8-aminoquinoline analogs of primaquine were selected for screening against a panel of seven
Plasmodium falciparum
clones and isolates. Six of the 13 8-aminoquinolines had average 50% inhibitory concentrations between 50 and 100 nM against these
P. falciparum
clones and were thus an order of magnitude more potent than primaquine. However, excluding chloroquine-resistant clones and isolates, these 8-aminoquinolines were all an order of magnitude less potent than chloroquine. None of the 8-aminoquinolines was cross resistant with either chloroquine or mefloquine. In contrast to the inactive primaquine prototype, 8 of the 13 8-aminoquinolines inhibited hematin polymerization more efficiently than did chloroquine. Although alkoxy or aryloxy substituents at position 5 uniquely endowed these 13 8-aminoquinolines with impressive schizontocidal activity, the structural specificity of inhibition of both parasite growth and hematin polymerization was low.
Amphotericin B- and Fluconazole-Resistant
Candida
spp.,
Aspergillus fumigatus
, and Other Newly Emerging Pathogenic Fungi Are Susceptible to Basic Antifungal Peptides
Authors: Helmerhorst Eva J. , Reijnders Ingrid M. , van ’t Hof Wim , Simoons-Smit Ina , Veerman Enno C. I. , Amerongen Arie V. Nieuw
Published: October 2018

The present study shows that a number of basic antifungal peptides, including human salivary histatin 5, a designed histatin analog designated dhvar4, and a peptide from frog skin, PGLa, are active against amphotericin B-resistant
Candida albicans
,
Candida krusei
, and
Aspergillus fumigatus
strains and against a fluconazole-resistant
Candida glabrata
isolate.
Pharmacodynamics of Vancomycin for the Treatment of Experimental Penicillin- and Cephalosporin-Resistant Pneumococcal Meningitis
Authors: Ahmed Amina , Jafri Hasan , Lutsar Irja , McCoig Cynthia C. , Trujillo Monica , Wubbel Loretta , Shelton Sharon , McCracken George H.
Published: October 2018

With the emergence of β-lactam antibiotic resistance among strains of
Streptococcus pneumoniae
, vancomycin has assumed an important role in the treatment of bacterial meningitis. Using the rabbit meningitis model, we evaluated the pharmacokinetics and pharmacodynamics of vancomycin in this setting. Animals were given 80 mg/kg of body weight daily in two or four divided doses to determine the penetration and activity of vancomycin in cerebrospinal fluid (CSF); each regimen was administered with and without dexamethasone. Mean peak (2 h) concentrations in CSF that were four- to eightfold higher than the minimum bactericidal concentration (MBC; 0.5 μg/ml) for the pathogen were adequate for bacterial clearance. In both groups concentrations in CSF remained higher than the MBC for greater than 80% of the respective dosing intervals, and the penetration of vancomycin into CSF was 20%. Mean concentrations in CSF at 24 to 36 h of therapy were lower than those achieved during the first 12 h, consistent with a decline in the level of antibiotic entry into CSF as inflammation wanes. Rates of bacterial clearance were similar for the two regimens, and for all animals cultures of CSF were sterile by 36 h. The coadministration of dexamethasone significantly reduced the penetration of vancomycin into CSF by 29% and significantly lowered the rate of bacterial clearance during the first 6 h in animals receiving 20-mg/kg doses of vancomycin. For animals receiving 40-mg/kg doses, therapeutic peak concentrations in CSF were obtained even with steroid use, suggesting that the effect of steroids may be circumvented by the use of larger daily doses of vancomycin.
Antimycobacterial Activities of Isoxyl and New Derivatives through the Inhibition of Mycolic Acid Synthesis
Authors: Phetsuksiri Benjawan , Baulard Alain R. , Cooper Andrea M. , Minnikin David E. , Douglas James D. , Besra Gurdyal S. , Brennan Patrick J.
Published: October 2018

Isoxyl (ISO), a thiourea (thiocarlide; 4,4′-diisoamyloxythiocarbanilide), demonstrated potent activity against
Mycobacterium tuberculosis
H37Rv (MIC, 2.5 μg/ml),
Mycobacterium bovis
BCG (MIC, 0.5 μg/ml),
Mycobacterium avium
(MIC, 2.0 μg/ml), and
Mycobacterium aurum
A+ (MIC, 2.0 μg/ml), resulting in complete inhibition of mycobacteria grown on solid media. Importantly, a panel of clinical isolates of
M. tuberculosis
from different geographical areas with various drug resistance patterns were all sensitive to ISO in the range of 1 to 10 μg/ml. In a murine macrophage model, ISO exhibited bactericidal killing of viable intracellular
M. tuberculosis
in a dose-dependent manner (0.05 to 2.50 μg/ml). The selective action of ISO on mycolic acid synthesis was studied through the use of [1,2-
14
C]acetate labeling of
M. tuberculosis
H37Rv,
M. bovis
BCG, and
M. aurum
A+. At its MIC for
M. tuberculosis
, ISO inhibited the synthesis of both fatty acids and mycolic acids (α-mycolates by 91.6%, methoxymycolates by 94.3%, and ketomycolates by 91.1%); at its MIC in
M. bovis
BCG, ISO inhibited the synthesis of α-mycolates by 87.2% and that of ketomycolates by 88.5%; and the corresponding inhibitions for
M. aurum
A+ were 87.1% for α-mycolates, 87.2% for ketomycolates, and 86.5% for the wax-ester mycolates. A comparison with isoniazid (INH) and ethionamide (ETH) demonstrated marked similarity in action, i.e., inhibition of the synthesis of all kinds of mycolic acids. However, unlike INH and ETH, ISO also inhibited the synthesis of shorter-chain fatty acids. ISO showed no acute toxicity against primary macrophage cell cultures as demonstrated by diminution of redox activity. A homologous series of ISO derivatives were synthesized. Most derivatives were as effective or more effective than the parent compound in the agar proportion assay. Thus, these thioureas, like INH and ETH, specifically inhibit mycolic acid synthesis and show promise in counteracting a wide variety of drug-sensitive and -resistant strains of
M. tuberculosis
.
Formation of Azole-Resistant
Candida albicans
by Mutation of Sterol 14-Demethylase P450
Authors: Asai Kentaro , Tsuchimori Noboru , Okonogi Kenji , Perfect John R. , Gotoh Osamu , Yoshida Yuzo
Published: October 2018

The sterol 14-demethylase P450 (CYP51) of a fluconazole-resistant isolate of
Candida albicans
, DUMC136, showed reduced susceptibility to this azole but with little change in its catalytic activity. Twelve nucleotide substitutions, resulting in four amino acid changes, were identified in the DUMC136
CYP51
gene in comparison with a reported
CYP51
sequence from a wild-type, fluconazole-susceptible
C. albicans
strain. Seven of these substitutions, including all of those causing amino acid changes, were located within a region covering one of the putative substrate recognition sites of the enzyme (SRS-1). Polymorphisms within this region were observed in several
C. albicans
isolates, and some were found to be
CYP51
heterozygotes. Among the amino acid changes occurring in this region, only an alteration of Y132 was common among these fluconazole-resistant isolates, which suggests the importance of this residue to the fluconazole resistance of the target enzyme. DUMC136 and another fluconazole-resistant isolate were homozygotes with respect to
CYP51
, although the typical wild-type, fluconazole-susceptible
C. albicans
was a
CYP51
heterozygote. These findings suggest that part of the fluconazole-resistant phenotype of
C. albicans
DUMC136 was acquired through a mutation-prone area of
CYP51
, an area which might promote the formation of fluconazole-resistant CYP51, along with a mechanism(s) which allows the formation of a homozygote of this altered CYP51 in this diploid pathogenic yeast.
Safety and Pharmacokinetics of an Intramuscular Monoclonal Antibody (SB 209763) against Respiratory Syncytial Virus (RSV) in Infants and Young Children at Risk for Severe RSV Disease
Authors: Meissner H. Cody , Groothuis Jessie R. , Rodriguez William J. , Welliver Robert C. , Hogg Geoff , Gray Peter H. , Loh Richard , Simoes Eric A. F. , Sly Peter , Miller Ann K. , Nichols Alice I. , Jorkasky Diane K. , Everitt Daniel E. , Thompson Kathleen A.
Published: October 2018

We conducted a multicenter, double-blind, placebo-controlled, randomized trial of a humanized monoclonal antibody against a respiratory syncytial virus (RSV) fusion protein (SB 209763) to evaluate its safety, pharmacokinetics, and fusion inhibition and neutralization titers. Forty-three infants who were either delivered prematurely (≤35 weeks’ gestation) or exhibited bronchopulmonary dysplasia were administered either single or repeat (two doses, 8 weeks apart) intramuscular injections of SB 209763 at a concentration of 0.25, 1.25, 5.0, or 10.0 mg/kg or of a placebo. Four of 229 adverse events were considered related to the study drug, including purpura (
n
= 3) and thrombocytosis (
n
= 1). No subject developed a detectable level of anti-SB 209763 antibody. Approximately 1 week after administration of the second dose of SB 209763 at 10 mg/kg, the mean plasma concentration (
n
= 9) was 68.5 μg/ml. The terminal half-life (
T
1/2
) determined by noncompartmental analysis ranged from 22 to 50 days. The population pharmacokinetics for SB 209763 following intramuscular administration was appropriately described by a one-compartment model with first-order input and elimination. Higher values for clearance and volume of distribution at steady state were observed for younger patients, with values decreasing to 0.143 (ml/h)/kg and 161 mL/kg, respectively, by a mean age of 298 days (∼10 months). The mean
T
1/2
of SB 209763 for the study population was 32.5 days. No other factor (dose, weight, gender, race, premature birth, or bronchopulmonary dysplasia) was observed to alter the population pharmacokinetics of SB 209763 in this study of infants and young children. The mean neutralization titer on day 6 was 286, and the mean fusion inhibition titer was 36. At least 57% of subjects dosed at 1.25 to 10.0 mg of SB 209763 per kg of body weight who were seronegative at baseline experienced a fourfold or greater increase in fusion inhibition titer. Nine RSV infections were documented during the 16-week course of the study; the numbers of RSV infections were similar for the different regimens, including the placebo. The doses of SB 209763 studied may have been insufficient to confer protection against RSV lower respiratory tract disease; these results suggest that additional trials using higher doses of monoclonal antibody for immunoprophylaxis should be considered.
Outer Membrane Permeability Barrier in
Escherichia coli
Mutants That Are Defective in the Late Acyltransferases of Lipid A Biosynthesis
Authors: Vaara Martti , Nurminen Marjatta
Published: October 2018

The tight packing of six fatty acids in the lipid A constituent of lipopolysaccharide (LPS) has been proposed to contribute to the unusually low permeability of the outer membrane of gram-negative enteric bacteria to hydrophobic antibiotics. Here it is shown that the
Escherichia coli msbB
mutant, which elaborates defective, penta-acylated lipid A, is practically as resistant to a representative set of hydrophobic solutes (rifampin, fusidic acid, erythromycin, clindamycin, and azithromycin) as the parent-type control strain. The susceptibility index, i.e., the approximate ratio between the MIC for the
msbB
mutant and that for the parent-type control, was maximally 2.7-fold. In comparison, the
rfa
mutant defective in the deep core oligosaccharide part of LPS displayed indices ranging from 20 to 64. The
lpxA
and
lpxD
lipid A mutants had indices higher than 512. Furthermore, the
msbB
mutant was resistant to glycopeptides (vancomycin, teicoplanin), whereas the
rfa
,
lpxA
, and
lpxD
mutants were susceptible. The
msbB htrB
double mutant, which elaborates even-more-defective, partially tetra-acylated lipid A, was still less susceptible than the
rfa
mutant. These findings indicate that hexa-acylated lipid A is not a prerequisite for the normal function of the outer membrane permeability barrier.
Activity of Moxifloxacin, Administered Once a Day, against
Streptococcus pneumoniae
in an In Vitro Pharmacodynamic Model of Infection
Authors: MacGowan Alasdair P. , Bowker Karen E. , Wootton Mandy , Holt H. Alan
Published: October 2018

The antibacterial effect of moxifloxacin was studied by using an in vitro pharmacodynamic model of infection with dosing simulations of 400 mg every 24 h for 48 h.
Streptococcus pneumoniae
was tested by using four wild-type strains for which the moxifloxacin MICs were 0.008, 0.12, 0.14, and 3.6 mg/liter. In addition, two isogenic mutants, generated from the strains for which the moxifloxacin MICs were ≤0.12 mg/liter and for which the MICs were 1.0 and 1.6 mg/liter, were also used. Antibacterial efficacy was measured by the following indices: log change in viable count at 12, 24, 36, and 48 h; area under the bacterial kill curve (AUBKC); and time to kill 99.9% of the initial inoculum. With the three strains for which the moxifloxacin MICs were ≤0.14 mg/liter, there was a marked reduction in viable count over 12 to 36 h; in contrast, with strains for which the MICs were ≥1.0 mg/liter, little killing occurred over 48 h. A sigmoid dose-response model indicated that the area under the curve/MIC ratio was strongly related to the log change in viable count at 24 and 48 h and to the AUBKC. These data indicate that moxifloxacin may have a role in management of
S. pneumoniae
infection.
Safety and Pharmacokinetics of Amprenavir (141W94), a Human Immunodeficiency Virus (HIV) Type 1 Protease Inhibitor, following Oral Administration of Single Doses to HIV-Infected Adults
Authors: Sadler Brian M. , Hanson Cynthia D. , Chittick Gregory E. , Symonds William T. , Roskell Neil S.
Published: October 2018

We conducted a double-blind, placebo-controlled, parallel, dose-escalation trial to evaluate the pharmacokinetics and safety of single, oral doses of amprenavir (141W94; formerly VX-478), a potent inhibitor of human immunodeficiency virus (HIV) type 1 protease, administered as hard gelatin capsules in 12 HIV-infected subjects. The doses of amprenavir evaluated were 150, 300, 600, 900, and 1,200 mg. Amprenavir was rapidly absorbed, with the time to maximum concentration occurring within 1 to 2 h after dosing. On the basis of power model analysis, the increase in the maximum concentration of amprenavir in plasma (
C
max
) was less than dose proportional, and the increase in the area under the concentration-time curve from time zero to infinity (AUC
0–∞
) was greater than dose proportional; mean slopes (with 90% confidence intervals) were 1.25 (1.16 to 1.35) and 0.78 (0.78 to 0.86) for AUC
0–∞
and
C
max
, respectively. Amprenavir was eliminated slowly, with a terminal-phase half-life of 8 h. A second study was conducted to determine the bioavailability of the hard gelatin capsule relative to that of a subsequently developed soft gelatin capsule. The capsules were bioequivalent in terms of AUC
0–∞
but not in terms of
C
max
; geometric-least-squares means ratios (with 90% confidence intervals) were 1.03 (0.92 to 1.14) and 1.25 (1.03 to 1.53) for AUC
0–∞
and
C
max
, respectively. Administration of soft gelatin capsules of amprenavir with a high-fat breakfast resulted in a 14% decrease in the mean AUC
0–∞
(from 9.58 to 8.26 μg · h/ml), which is not likely to be clinically significant. The most common adverse events related to amprenavir were headache, nausea, and hypesthesia. Amprenavir appears to be safe and well tolerated over the dose range of 150 to 1200 mg. On the basis of the present single-dose studies, amprenavir is an HIV protease inhibitor with favorable absorption and clearance pharmacokinetics that are only minimally affected by administration with food.
Use of the Hepatitis B Virus Recombinant Baculovirus-HepG2 System to Study the Effects of (−)-β-2′,3′-Dideoxy-3′-Thiacytidine on Replication of Hepatitis B Virus and Accumulation of Covalently Closed Circular DNA
Authors: Delaney William E. , Miller Thomas G. , Isom Harriet C.
Published: October 2018

(−)-β-2′,3′-Dideoxy-3′-thiacytidine (lamivudine [3TC]) is a nucleoside analog which effectively interferes with the replication of hepatitis B virus (HBV) DNA in vitro and in vivo. We have investigated the antiviral properties of 3TC in vitro in HepG2 cells infected with recombinant HBV baculovirus. Different types of information can be obtained with the HBV baculovirus-HepG2 system because (i) experiments can be carried out at various levels of HBV replication including levels significantly higher than those that can be obtained from conventional HBV-expressing cell lines, (ii) cultures can be manipulated and/or treated prior to or during the initiation of HBV expression, and (iii) high levels of HBV replication allow the rapid detection of HBV products including covalently closed circular (CCC) HBV DNA from low numbers of HepG2 cells. The treatment of HBV baculovirus-infected HepG2 cells with 3TC resulted in an inhibition of HBV replication, evidenced by reductions in the levels of both extracellular HBV DNA and intracellular replicative intermediates. The effect of 3TC on HBV replication was both dose and time dependent, and the reductions in extracellular HBV DNA that we observed agreed well with the previously reported efficacy of 3TC in vitro. As expected, levels of HBV transcripts and extracellular hepatitis B surface antigen and e antigen were not affected by 3TC. Importantly, the HBV baculovirus-HepG2 system made it possible to observe for the first time that CCC HBV DNA levels are lower in cells treated with 3TC than in control cells. We also observed that the treatment of HepG2 cells prior to HBV baculovirus infection resulted in a slight increase in the efficacy of 3TC compared to treatments starting 24 h postinfection. The treatment of HepG2 cells with the highest concentration of 3TC tested in this study (2 μM) prior to the initiation of HBV replication markedly inhibited the accumulation of CCC DNA, whereas treatment with the same concentration of 3TC at a time when CCC HBV DNA pools were established within the cells was considerably less effective. In addition, our results suggest that in HepG2 cells, non-protein-associated relaxed circular HBV DNA and particularly CCC HBV DNA are considerably more resistant to 3TC treatment than other forms of HBV DNA, including replicative intermediates and extracellular DNA. We conclude from these studies that the HBV baculovirus-HepG2 system has specific advantages for drug studies and can be used to complement other in vitro model systems currently used for testing antiviral compounds.
Antitrypanosomal Activity of Fluoroquinolones
Authors: Nenortas Elizabeth , Burri Christian , Shapiro Theresa A.
Published: October 2018

Six fluoroquinolones presently in clinical use and four investigational tetracyclic fluoroquinolones were tested for in vitro activity against bloodstream-form
Trypanosoma brucei brucei
. All compounds had measurable activity, but the tetracyclic analogs were most potent, with 50% effective concentrations in the low micromolar range. In general, trypanosomes were more susceptible than L1210 leukemia cells. Consistent with the notion that they target type II topoisomerase in trypanosomes, the fluoroquinolones promote the formation of protein-DNA covalent complexes.
Effects of Enrofloxacin on Porcine Phagocytic Function
Authors: Schoevers E. J. , van Leengoed L. A. M. G. , Verheijden J. H. M. , Niewold T. A.
Published: October 2018

The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin. Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs). Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen. Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 μg/ml. Enrofloxacin (0.5 μg/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or
Actinobacillus pleuropneumoniae
,
Pasteurella multocida
, and
Staphylococcus aureus
. Significant differences in intracellular killing were seen with enrofloxacin at 5× the MIC compared with that for controls not treated with enrofloxacin. PMNs killed all
S. aureus
isolates in 3 h with or without enrofloxacin. Intracellular
S. aureus
isolates in AMs were less susceptible than extracellular
S. aureus
isolates to the bactericidal effect of enrofloxacin.
P. multocida
was not phagocytosed by PMNs. AMs did not kill
P. multocida
, and similar intra- and extracellular reductions of
P. multocida
isolates by enrofloxacin were found. Intraphagocytic killing of
A. pleuropneumoniae
was significantly enhanced by enrofloxacin at 5× the MIC in both PMNs and AMs. AMs are very susceptible to the
A. pleuropneumoniae
cytotoxin. This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance.
The Genes
degQ
,
pps
, and
lpa-8
(
sfp
) Are Responsible for Conversion of
Bacillus subtilis
168 to Plipastatin Production
Authors: Tsuge Kenji , Ano Takashi , Hirai Mitsuyo , Nakamura Yoshiyuki , Shoda Makoto
Published: October 2018

Bacillus subtilis
YB8 produces the lipopeptide antibiotic plipastatin.
B. subtilis
MI113, which is a derivative of strain 168, was converted into a new plipastatin producer, strain 406, by competence transformation with the chromosomal DNA of YB8. Transposon mini-Tn
10
insertional mutagenesis was applied to strain 406, which revealed that
lpa-8
(
sfp
) (encoding 4′-phosphopantetheinyl transferase) and the
pps
operon (located between 167 and 171°) are essential for plipastatin production. The
pps
operon was previously suggested to encode putative peptide synthetases (A. Tognoni, E. Franchi, C. Magistrelli, E. Colombo, P. Cosmina, and G. Grandi, Microbiology 141:645–648, 1995) and was thought to be the fengycin operon (V. Tosato, A. M. Albertini, M. Zotti, S. Sonda, and C. V. Bruschi, Microbiology 143:3443–3450, 1997). We claim that the
pps
operon is the
pli
operon, encoding plipastatin synthetase. By using a new high-performance liquid chromatography system, we revealed that strain 168 expressing only
lpa-8
can also produce plipastatin, although the yield is very low. However, the introduction of the pleiotropic regulator
degQ
of strain YB8 into strain 168 expressing
lpa-8
resulted in a 10-fold increase in the production of plipastatin.
Carbaryl as a Carbon and Nitrogen Source: an Inducible Methylamine Metabolic Pathway at the Biochemical and Molecular Levels in
Pseudomonas
sp. Strain C5pp
Authors: Kamini  , Sharma Rakesh , Punekar Narayan S. , Phale Prashant S.
Published: October 2018

The degradation of xenobiotics plays a significant role in the environment to maintain ecological systems as well as to prevent the imbalance of biogeochemical cycles via carbon-nitrogen cycling. Carbaryl is the most widely used pesticide from the carbamate family.
Pseudomonas
sp. strain C5pp, capable of utilizing carbaryl as a carbon and nitrogen source for its growth, subsequently helps in complete remediation of carbaryl. Thus, it maintains the ecosystem by balancing the biogeochemical cycles. The metabolic versatility and genetic diversity of strain C5pp for the transformation of contaminants like carbaryl and 1-naphthol into less harmful products make it a suitable candidate from the perspective of bioremediation.
Streptococcus mutans yidC1
and
yidC2
Impact Cell Envelope Biogenesis, the Biofilm Matrix, and Biofilm Biophysical Properties
Authors: Palmer Sara R. , Ren Zhi , Hwang Geelsu , Liu Yuan , Combs Ashton , Söderström Bill , Lara Vasquez Patricia , Khosravi Yalda , Brady L. Jeannine , Koo Hyun , Stoodley Paul
Published: October 2018

YidC proteins are membrane-localized chaperone insertases that are universally conserved in all bacteria and are traditionally studied in the context of membrane protein insertion and assembly. Both YidC paralogs of the cariogenic pathogen
Streptococcus mutans
are required for proper envelope biogenesis and full virulence, indicating that these proteins may also contribute to optimal biofilm formation in streptococci. Here, we show that the deletion of either
yidC
results in changes to the structure and physical properties of the EPS matrix produced by
S. mutans
, ultimately impairing optimal biofilm development, diminishing its mechanical stability, and facilitating its removal. Importantly, the universal conservation of bacterial
yidC
orthologs, combined with our findings, provide a rationale for YidC as a possible drug target for antibiofilm therapies.
Discovery of
mcr-1
-Mediated Colistin Resistance in a Highly Virulent Escherichia coli Lineage
Authors: Forde Brian M. , Zowawi Hosam M. , Harris Patrick N. A. , Roberts Leah , Ibrahim Emad , Shaikh Nissar , Deshmukh Anand , Sid Ahmed Mazen A. , Al Maslamani Muna , Cottrell Kyra , Trembizki Ella , Sundac Lana , Yu Heidi H. , Li Jian , Schembri Mark A. , Whiley David M. , Paterson David L. , Beatson Scott A.
Published: October 2018

Escherichia coli
ST95 is a globally disseminated clone frequently associated with bloodstream infections and neonatal meningitis. However, the ST95 lineage is defined by low levels of drug resistance amongst clinical isolates, which normally provides for uncomplicated treatment options. Here, we provide the first detailed genomic analysis of an
E. coli
ST95 isolate that has both high virulence potential and resistance to multiple antibiotics. Using the genome, we predicted its virulence and antibiotic resistance mechanisms, which include resistance to last-line antibiotics mediated by the plasmid-borne
mcr-1
gene. Finding an ST95 isolate resistant to nearly all antibiotics that also has a high virulence potential is of major clinical importance and underscores the need to monitor new and emerging trends in antibiotic resistance development in this important global lineage.
Visual deficit possibly caused by lutetium-177 PSMA treatment
Authors: van Kalmthout Ludwike , Stam Anine , Gans Renze , Lam Marnix
Published: October 2018

This report describes a case of a 54-year-old man who underwent lutetium-177-PSMA therapy in the setting of metastatic castration-resistant prostate cancer (mCRPC) in the University Medical Center Utrecht. Following administration of the second cycle, patient presented with a slowly impairing, bilateral visual loss. This clinical presentation was most likely the result of the high intracranial pressure due to impediment of cerebrospinal fluid circulation, possibly related to obstructive dural thickness, being either caused by dural and/or leptomeningeal metastases of advanced mCRPC or by local radiation effects following lutetium-177-PSMA therapy. Describing this case, we aim to add to the discussion on 177Lu-PSMA safety, in which prospective research will ultimately offer definite answers.
DRESS syndrome-associated acute necrotizing eosinophilic myocarditis with giant cells
Authors: Kowtoniuk Robert , Pinninti Mamatha , Tyler William , Doddamani Sanjay
Published: October 2018

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an uncommon drug hypersensitivity reaction caused by a wide variety of agents. It has a characteristic latent period between 2 and 8 weeks from the onset of drug ingestion followed by a slow resolution with the potential for relapse. Despite being a potentially fatal disease, little is understood about its variable clinical presentation and why it can present long after removal of the offending drug. Visceral organ involvement typically occurs, but rarely results in clinically manifested cardiac injury. In its most aggressive form, acute necrotizing eosinophilic myocarditis (ANEM) can present with DRESS. We present an unusual case of DRESS syndrome due to lamotrigine with confirmed ANEM showing both eosinophils and rare giant cell infiltrates on endomyocardial biopsy. Although lamotrigine has been reported to cause DRESS, it has not been previously implicated as a cause of ANEM.
Implementing a mobile diagnostic unit to increase access to imaging and laboratory services in western Kenya
Authors: Dhoot Roshni , Humphrey John M , O'Meara Patrick , Gardner Adrian , McDonald Clement J , Ogot Kelvin , Antani Sameer , Abuya Joseph , Kohli Marc
Published: October 2018

Access to basic imaging and laboratory services remains a major challenge in rural, resource-limited settings in sub-Saharan Africa. In 2016, the Academic Model Providing Access to Healthcare programme in western Kenya implemented a mobile diagnostic unit (MDU) outfitted with a generator-powered X-ray machine and basic laboratory tests to address the lack of these services at rural, low-resource, public health facilities. The objective of this paper is to describe the design, implementation, preliminary impact and operational challenges of the MDU in western Kenya. Since implementing the MDU at seven rural health facilities serving a catchment of over half a million people, over 4500 chest radiographs have been performed, with one or more abnormalities detected in approximately 30% of radiographs. We observed favorable feedback and uptake of MDU services by healthcare workers and patients. However, various operational challenges in the design and construction of the MDU and the transmission and reporting of radiographs in remote areas were encountered. Our experience supports the feasibility of deploying an MDU to increase access to basic radiology and laboratory services in rural, resource-limited settings.
Using the Model for Improvement to implement the Critical-Care Pain Observation Tool in an adult intensive care unit
Authors: Mascarenhas Mairi , Beattie Michelle , Roxburgh Michelle , MacKintosh John , Clarke Noreen , Srivastava Devjit
Published: October 2018

Managing pain is challenging in the intensive care unit (ICU) as often patients are unable to self-report due to the effects of sedation required for mechanical ventilation. Minimal sedative use and the utilisation of analgesia-first approaches are advocated as best practice to reduce unwanted effects of oversedation and poorly managed pain. Despite evidence-based recommendations, behavioural pain assessment tools are not readily implemented in many critical care units. A local telephone audit conducted in April 2017 found that only 30% of Scottish ICUs are using these validated pain instruments. The intensive care unit (ICU) at Raigmore Hospital, NHS Highland, initiated a quality improvement (QI) project using the Model for Improvement (MFI) to implement an analgesia-first approach utilising a validated and reliable behavioural pain assessment tool, namely the Critical-Care Pain Observation Tool (CPOT). Over a six-month period, the project deployed QI tools and techniques to test and implement the CPOT. The process measures related to (i) the nursing staff’s reliability to assess and document pain scores at least every four hours and (ii) to treat behavioural signs of pain or CPOT scores ≥ 3 with a rescue bolus of opioid analgesia. The findings from this project confirm that the observed trends in both process measures had reduced over time. Four hourly assessments of pain had increased to 89% and the treatment of CPOT scores ≥3 had increased to 100%.
Association between Fine Particulate Matter and Oral Cancer among Taiwanese Men
Authors: Chu Yu-Hua , Kao Syuan-Wei , Tantoh Disline Manli , Ko Pei-Chieh , Lan Shou-Jen , Liaw Yung-Po
Published: October 2018

The aim of this study was to investigate the association between fine particulate matter 2.5 (PM2.5) and oral cancer among Taiwanese men. Four linked data sources including the Taiwan Cancer Registry, Adult Preventive Medical Services Database, National Health Insurance Research Database, and Air Quality Monitoring Database were used. Concentrations of sulfur dioxide, carbon monoxide, ozone, NOx (nitrogen monoxide and nitrogen dioxide), coarse particulate matter (PM10-2.5) and PM2.5 in 2009 were assessed in quartiles. A total of 482 659 men aged 40 years and above were included in the analysis. Logistic regression was used to examine the association between PM2.5 and oral cancer diagnosed from 2012 to 2013. After adjusting for potential confounders, the ORs of oral cancer were 0.91 (95% CI 0.75 to 1.11) for 26.74≤PM2.5<32.37, 1.01 (95% CI 0.84 to 1.20) for 32.37≤PM2.5<40.37 μg/m3 and 1.43 (95% CI 1.17 to 1.74) for PM2.5≥40.37 μg/m3 compared with PM2.5<26.74 μg/m3. In this study, there was an increased risk of oral cancer among Taiwanese men who were exposed to higher concentrations of PM2.5.
Apraxia screening predicts Alzheimer pathology in frontotemporal dementia
Authors: Pawlowski Matthias , Joksch Viktoria , Wiendl Heinz , Meuth Sven G , Duning Thomas , Johnen Andreas
Published: October 2018

Objectives

Frontotemporal dementia (FTD) is a heterogeneous clinical syndrome linked to diverse types of underlying neuropathology. Diagnosis is mainly based on clinical presentation and accurate prediction of underlying neuropathology remains difficult.

Methods

We present a large cohort of patients with FTD spectrum diseases (n=84). All patients were thoroughly characterised by cerebrospinal fluid (CSF) Alzheimer’s disease (AD) biomarkers, neuroimaging, neuropsychological testing and standardised apraxia screening.

Results

A potential AD pathology was found in 43% of patients with FTD. CSF AD biomarker levels positively correlated with AD-typical apraxia scores in patients with FTD. The discriminative power of apraxia test results indicative of AD pathology was high (sensitivity: 90%, specificity: 66%).

Conclusions

Apraxia is common in neurodegenerative dementias but under-represented in clinical workup and diagnostic criteria. Standardised apraxia screening may serve as bedside test to objectify an AD-typical apraxia profile as an early and robust sign of AD pathology in patients with FTD.
Disseminated cerebral hydatid disease (multiple intracranial echinococcosis)
Authors: Svrckova Patricia , Nabarro Laura , Chiodini Peter L , Jäger Hans Rolf
Published: October 2018

Intracranial echinococcosis is relatively uncommon and usually occurs in the context of echinococcal lesions elsewhere in the body, mostly liver and lung. Multiple intracranial lesions can result from rupture of an initial single intracranial cyst (in cystic echinococcosis) or from dissemination of systemic disease of the lung, liver or heart (cystic and alveolar echinococcosis). The two main subtypes, cystic and alveolar echinococcosis, present differently and have distinct imaging features in the brain. We discuss the presentation, imaging findings and clinical course of three cases (two cystic and one alveolar) of intracranial echinococcal disease in adults.