bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro Activities of 13 Fluoroquinolones against
Staphylococcus aureus
Isolates with Characterized Mutations in
gyrA
,
gyrB
,
grlA
, and
norA
and against Wild-Type Isolates
Authors: Muñoz Bellido J. L. , Alonso Manzanares M. A. , Yagüe Guirao G. , Gutiérrez Zufiaurre M. N. , Toldos M. C. M. , Segovia Hernández M. , García-Rodríguez J. A.
Published: October 2018

The in vitro activities of 13 fluoroquinolones (FQs) were tested against 90
Staphylococcus aureus
clinical isolates: 30 wild type for
gyrA
,
gyrB
,
grlA
and
norA
and 60 with mutations in these genes. Clinafloxacin (CI-960), sparfloxacin, and grepafloxacin were the most active FQs against wild-type isolates (MICs at which 90% of isolates were inhibited, 0.06 to 0.1 μg/ml). Mutations in
grlA
did not affect the MICs of newer FQs.
grlA-gyrA
double mutations led to higher MICs for all the FQs tested. Efflux mechanisms affected the newer FQs to a much lesser extent than the less recently developed FQs.
The Anti-Influenza Virus Drug Rimantadine Has Trypanocidal Activity
Authors: Kelly John M. , Miles Michael A. , Skinner Anita C.
Published: October 2018

We report here that bloodstream forms of the African trypanosome,
Trypanosoma brucei
, are sensitive to the anti-influenza virus drug rimantadine (50% inhibitory concentration of 1.26 μg ml
−1
at pH 7.4). The activity is pH dependent and is consistent with a mechanism involving inhibition of the ability to regulate internal pH. Rimantadine is also toxic to the trypanosomatid parasites
Trypanosoma cruzi
and
Leishmania major.
Activities of Several Novel Oxazolidinones against
Mycobacterium tuberculosis
in a Murine Model
Authors: Cynamon M. H. , Klemens S. P. , Sharpe C. A. , Chase S.
Published: October 2018

The activities of linezolid, eperezolid, and PNU-100480 were evaluated in a murine model of tuberculosis. Approximately 10
7
viable
Mycobacterium tuberculosis
ATCC 35801 organisms were given intravenously to 4-week-old outbred CD-1 mice. In the first study, treatment was started 1 day postinfection and was given by gavage for 4 weeks. Viable cell counts were determined from homogenates of spleens and lungs. PNU-100480 was as active as isoniazid. Linezolid was somewhat less active than PNU-100480 and isoniazid. Eperezolid had little activity in this model. In the next two studies, treatment was started 1 week postinfection. A dose-response study was performed with PNU-100480 and linezolid (both at 25, 50, and 100 mg/kg of body weight). PNU-100480 was more active than linezolid, and its efficacy increased with an escalation of the dose. Subsequently, the activity of PNU-100480 alone and in combination with rifampin or isoniazid was evaluated and was compared to that of isoniazid-rifampin. The activity of PNU-100480 was similar to that of isoniazid and/or rifampin in the various combinations tested. Further evaluation of these oxazolidinones in the murine test system would be useful prior to the development of clinical studies with humans.
In Vitro Activity of Syn-2869, a Novel Triazole Agent, against Emerging and Less Common Mold Pathogens
Authors: Johnson Elizabeth M. , Szekely Adrien , Warnock David W.
Published: October 2018

The in vitro activity of Syn-2869 was compared with that of amphotericin B and itraconazole. MICs for 100 isolates of pathogenic molds belonging to 12 species were determined by a broth microdilution adaptation of the method recommended by the National Committee for Clinical Laboratory Standards. Syn-2869 and itraconazole showed comparable, good activity against the dematiaceous molds
Cladophialophora bantiana
,
Cladophialophora carrionii
,
Exophiala dermatitidis
,
Fonsecaea pedrosoi
,
Phialophora parasitica
, and
Ramichloridium mackenziei
. Neither of the azole agents was active against the hyaline molds
Fusarium solani
,
Scedosporium prolificans
, and
Scopulariopsis brevicaulis
, but both were more active than amphotericin B against
Scedosporium apiospermum
. The MICs of the three agents were comparable for the mucoraceous mold
Absidia corymbifera
, but Syn-2869 appeared to be the least active against the dimorphic mold
Sporothrix schenckii
. Our results suggest that Syn-2869 could be effective against a range of mold infections in humans.
Use of a Genetic Approach To Evaluate the Consequences of Inhibition of Efflux Pumps in
Pseudomonas aeruginosa
Authors: Lomovskaya Olga , Lee Angela , Hoshino Kazuki , Ishida Hiroko , Mistry Anita , Warren Mark S. , Boyer Eric , Chamberland Suzanne , Lee Ving J.
Published: October 2018

Drug efflux pumps in
Pseudomonas aeruginosa
were evaluated as potential targets for antibacterial therapy. The potential effects of pump inhibition on susceptibility to fluoroquinolone antibiotics were studied with isogenic strains that overexpress or lack individual efflux pumps and that have various combinations of efflux- and target-mediated mutations. Deletions in three efflux pump operons were constructed. As expected, deletion of the MexAB-OprM efflux pump decreased resistance to fluoroquinolones in the wild-type
P. aeruginosa
(16-fold reduction for levofloxacin [LVX]) or in the strain that overexpressed
mexAB-oprM
operon (64-fold reduction for LVX). In addition to that, resistance to LVX was significantly reduced even for the strains carrying target mutations (64-fold for strains for which LVX MICs were >4 μg/ml). We also studied the frequencies of emergence of LVX-resistant variants from different deletion mutants and the wild-type strain. Deletion of individual pumps or pairs of the pumps did not significantly affect the frequency of emergence of resistant variants (at 4× the MIC for the wild-type strain) compared to that for the wild type (10
−6
to 10
−7
). In the case of the strain with a triple deletion, the frequency of spontaneous mutants was undetectable (<10
−11
). In summary, inhibition of drug efflux pumps would (i) significantly decrease the level of intrinsic resistance, (ii) reverse acquired resistance, and (iii) result in a decreased frequency of emergence of
P. aeruginosa
strains highly resistant to fluoroquinolones in clinical settings.
Characterization of Novel Antimicrobial Peptoids
Authors: Goodson Bob , Ehrhardt Anton , Ng Simon , Nuss John , Johnson Kirk , Giedlin Marty , Yamamoto Ralph , Moos Walter H. , Krebber Anke , Ladner Martha , Giacona Mary Beth , Vitt Charles , Winter Jill
Published: October 2018

Peptoids differ from peptides in that peptoids are composed of N-substituted rather than alpha-carbon-substituted glycine units. In this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition. In vitro, the peptoid CHIR29498 and some of its analogues were active in the range of 3 to 12 μg/ml against a panel of gram-positive and gram-negative bacteria which included isolates which were resistant to known antibiotics. Peptoid antimicrobial activity against
Staphylococcus aureus
was rapid, bactericidal, and independent of protein synthesis. β-Galactosidase and propidium iodide leakage assays indicated that the membrane is the most likely target of activity. Positional isomers of an active peptoid were also active, consistent with a mode of action, such as membrane disruption, that does not require a specific fit between the molecule and its target. In vivo, CHIR29498 protected
S. aureus
-infected mice in a simple infection model.
Piperacillin and Tazobactam Exhibit Linear Pharmacokinetics after Multiple Standard Clinical Doses
Authors: Auclair Barbara , Ducharme Murray P.
Published: October 2018

A population pharmacokinetic (PK) analysis was conducted to determine if piperacillin and tazobactam exhibited linear or nonlinear PKs and if incremental changes in the daily dosage of piperacillin affected tazobactam PKs. Four dosage groups were evaluated after multiple dosing regimens. Concentrations of drug in plasma and amounts in urine were best fitted by using a linear two-compartment PK model. No significant difference between dosing groups was seen for any piperacillin or tazobactam PK parameters. Both drugs exhibited linear PKs when given at usual clinical doses. Tazobactam PKs did not appear to be affected by the different dosing regimens of piperacillin.
Effect of HSR-903, a New Fluoroquinolone, on the Concentration of Theophylline in Serum
Authors: Niki Yoshihito , Watanabe Shinsuke , Tamada Sadao , Yoshida Koichiro , Miyashita Naoyuki , Nakajima Masamitu , Matsushima Toshiharu , Sekino Hisayuki , Matsuoka Osamu
Published: October 2018

The effect of HSR-903, a new fluoroquinolone, on the concentration of theophylline in serum in healthy male volunteers was investigated. The concentration of theophylline in serum and the urinary excretion rates of theophylline on day 5 of concomitant dosing with HSR-903 tended to increase compared to those on day 4, when theophylline was given alone; however, the urinary excretion rates of 1-methyluric acid and 3-methylxanthine on day 5 of concomitant dosing with HSR-903 tended to decrease in comparison to those on day 4, when theophylline was given alone.
Pharmacokinetics and Pharmacodynamics of Amoxicillin-Sulbactam, a Novel Aminopenicillin–β-Lactamase Inhibitor Combination, against
Escherichia coli
Authors: Bantar Carlos , Nicola Federico , Arenoso Hector J. , Galas Marcelo , Soria Liliana , Dana Diego , Rossi Alicia , Bianchini Hebe , Jasovich Abel
Published: October 2018

We evaluated the pharmacokinetics of amoxicillin-sulbactam (AMX-SUL), a novel drug combination, and its pharmacodynamics against
Escherichia coli
in 12 volunteers receiving a single oral dose (1,000 mg). Peak serum bactericidal and urine inhibitory activities in most volunteers were observed against
E. coli
strains for which AMX-SUL MICs were low (2- to 4-mg/liter) (2 strains) and high (≥16-mg/liter) (47 strains), respectively.
Cloning and Characterization of
bla
VIM
, a New Integron-Borne Metallo-β-Lactamase Gene from a
Pseudomonas aeruginosa
Clinical Isolate
Authors: Lauretti Laura , Riccio Maria Letizia , Mazzariol Annarita , Cornaglia Giuseppe , Amicosante Gianfranco , Fontana Roberta , Rossolini Gian Maria
Published: October 2018

Production of a metallo-β-lactamase activity was detected in a carbapenem-resistant
Pseudomonas aeruginosa
clinical isolate (isolate VR-143/97) from an Italian inpatient at the Verona University Hospital (northern Italy). The metallo-β-lactamase determinant was isolated from a genomic library of VR-143/97, constructed in an
Escherichia coli
plasmid vector, by screening for clones with reduced susceptibility to imipenem. Sequencing of the cloned gene revealed that it encoded a new class B β-lactamase that was named VIM-1. At the sequence level VIM-1 was rather divergent from the other class B enzymes (16.4 to 38.7% identity), overall being more similar to members of subclass B1 including the β-lactamase II of
Bacillus cereus
(Bc-II), the
Bacteroides fragilis
CcrA, the
Chryseobacterium meningosepticum
BlaB, and the cassette-encoded IMP-1 enzymes. Among these, VIM-1 showed the highest degree of similarity to Bc-II. Similarly to
bla
IMP
,
bla
VIM
was also found to be carried on a gene cassette inserted into a class 1 integron. The
bla
VIM
-containing integron was located on the chromosome of
P. aeruginosa
VR-143/97, and the metallo-β-lactamase-encoding determinant was not transferable to
E. coli
by conjugation. Expression of the integron-borne
bla
VIM
gene in
E. coli
resulted in a significant decrease in susceptibility to a broad array of β-lactams (ampicillin, carbenicillin, piperacillin, mezlocillin, cefotaxime, cefoxitin, ceftazidime, cefoperazone, cefepime, and carbapenems), revealing a very broad substrate specificity of the VIM-1 enzyme.
β-Lactamase Production by Oral Anaerobic Gram-Negative Species in Infants in Relation to Previous Antimicrobial Therapy
Authors: Nyfors S. , Könönen E. , Takala A. , Jousimies-Somer H.
Published: October 2018

The frequency of β-lactamase production in gram-negative bacteria has increased considerably during recent years. In this study, β-lactamase production by oral anaerobic gram-negative rods isolated from saliva was longitudinally examined for 44 Caucasian infants at the ages of 2, 6, and 12 months in relation to their documented exposure to antibiotics. Isolates showing decreased susceptibility to penicillin G (1 μg/ml) were examined for β-lactamase production by using a chromogenic cephalosporin disk test. β-Lactamase-positive, gram-negative anaerobic species were found in 11, 55, and 89% of each age group, respectively. β-Lactamase production was most frequent among organisms of the
Prevotella melaninogenica
group. At 12 months, 73% of the infants harbored β-lactamase-producing members of the
P. melaninogenica
group, 55% had nonpigmented
Prevotella
species, 25% had
Porphyromonas catoniae
, 23% had
Fusobacterium nucleatum
, and 5% had
Capnocytophaga
species. Several β-lactamase-producing species could be simultaneously found in the infants’ mouths. The presence of β-lactamase-producing species was significantly associated with the infants’ exposure to antibiotics through antimicrobial treatments given to the infants and/or their mothers.
Antifungal Properties and Target Evaluation of Three Putative Bacterial Histidine Kinase Inhibitors
Authors: Deschenes Robert J. , Lin Hong , Ault Addison D. , Fassler Jan S.
Published: October 2018

Histidine protein kinases have been explored as potential antibacterial drug targets. The recent identification of two-component histidine kinases in fungi has led us to investigate the antifungal properties of three bacterial histidine kinase inhibitors (RWJ-49815, RWJ-49968, and RWJ-61907). All three compounds were found to inhibit growth of the
Saccharomyces cerevisiae
and
Candida albicans
strains, with MICs ranging from 1 to 20 μg/ml. However, deletion of
SLN1
, the only histidine kinase in
S. cerevisiae
, did not alter drug efficacy. In vitro kinase assays were performed by using the Sln1 histidine kinase purified from bacteria as a fusion protein to glutathione
S
-transferase. RWJ-49815 and RWJ-49968 inhibited kinase a 50% inhibitory concentration of 10 μM, whereas RWJ-61907 failed to inhibit at concentrations up to 100 μM. Based on these results, we conclude that these compounds have antifungal properties; however, their mode of action appears to be independent of histidine kinase inhibition.
Characterization of New Mutations in Pyrazinamide-Resistant Strains of
Mycobacterium tuberculosis
and Identification of Conserved Regions Important for the Catalytic Activity of the Pyrazinamidase PncA
Authors: Lemaitre Nadine , Sougakoff Wladimir , Truffot-Pernot Chantal , Jarlier Vincent
Published: October 2018

A new set of mutations, including transposition of the insertion sequence IS
6110
, was identified in the
pncA
gene from 19 pyrazinamide-resistant
Mycobacterium tuberculosis
strains. Alignment of the PncA protein from
M. tuberculosis
with homologous proteins from different bacterial species revealed three highly conserved regions in PncA which may play an important role in the processing of pyrazinamide.
In Vitro Activity of HSR-903, a New Oral Quinolone, against Bacteria Causing Respiratory Infections
Authors: Watanabe Akira , Tokue Yutaka , Takahashi Hiroshi , Kikuchi Tohru , Kobayashi Takao , Gomi Kazunori , Fujimura Shigeru , Nukiwa Toshihiro
Published: October 2018

The in vitro activity of HSR-903, an oral quinolone, against 196 recent clinical isolates of respiratory pathogens was evaluated. HSR-903 was 2 to 32 times more active than ofloxacin, ciprofloxacin, and sparfloxacin against
Staphylococcus aureus
, including methicillin-resistant strains, and
Streptococcus pneumoniae
and was at least as active as the other quinolones against gram-negative pathogens.
Construction and Characterization of Mutants of the TEM-1 β-Lactamase Containing Amino Acid Substitutions Associated with both Extended-Spectrum Resistance and Resistance to β-Lactamase Inhibitors
Authors: Stapleton Paul D. , Shannon Kevin P. , French Gary L.
Published: October 2018

Extended-spectrum TEM β-lactamases (ESBLs) do not usually confer resistance to β-lactamase inhibitors such as clavulanate or tazobactam. To investigate the compatibility of the two phenotypes we used site-directed mutagenesis of the
bla
TEM-1
gene to introduce into the TEM-1 β-lactamase amino acid substitutions that confer the ESBL phenotype: TEM-12 (Arg164→Ser), TEM-26 (Arg164→Ser plus Glu104→Lys), TEM-19 (Gly238→Ser), and TEM-15 (Gly238→Ser plus Glu104→Lys). These were combined with three sets of substitutions that confer inhibitor resistance: TEM-31 (Arg244→Cys), TEM-33 (Met69→Leu), and TEM-35 (Met69→Leu and Asn276→Asp). Introduction of the Arg244→Cys substitution gave rise to inhibitor-resistant hybrid enzymes that either lost ESBL activity (TEM-12, TEM-15, and TEM-19) or had reduced activity (TEM-26) against ceftazidime. In contrast, the introduction of Met69→Leu or Met69→Leu plus Asn276→Asp substitutions did not significantly affect the abilities of the enzymes to confer resistance to ceftazidime, although increased susceptibility to cefotaxime was observed with
Escherichia coli
strains that expressed the TEM-19 and TEM-26 β-lactamases. With the exception of the TEM-12 β-lactamase, introduction of the Met69→Leu substitution did not give rise to enzymes with increased resistance to clavulanate compared to that of the TEM-1 β-lactamase. However, introduction of the double substitution Met69→Leu plus Asn276→Asp in the ESBLs did give rise to low-level (TEM-19, TEM-15, and TEM-26) or moderate-level (TEM-12) clavulanate resistance. None of the hybrid enzymes were as resistant to clavulanate as the corresponding inhibitor-resistant TEM β-lactamase mutant, suggesting that active-site configuration in the ESBLs limits the degree of clavulanate resistance conferred.
Safety and Tolerability of Fluconazole in Children
Authors: Novelli Vas , Holzel Helen
Published: October 2018

The safety profile of fluconazole was assessed for 562 children (ages, 0 to 17 years) comprising 323 males and 239 females. The data are derived from 12 clinical studies of fluconazole as prophylaxis or treatment for a variety of fungal infections in predominantly immunocompromised patients. Most children received multiple doses of fluconazole in the range of 1 to 12 mg/kg of body weight; a few received single doses. Administration was mainly by oral suspension or intravenous injection. Overall, 58 (10.3%) children reported 80 treatment-related side effects. The most common side effects were associated with the gastrointestinal tract (7.7%) or skin (1.2%). Self-limiting, treatment-related side effects affecting the liver and biliary system were reported in three patients (0.5%). Overall, 18 patients (3.2%) discontinued treatment due to side effects, mainly gastrointestinal symptoms. Dose and age did not appear to influence the incidence and pattern of side effects. Treatment-related laboratory abnormalities were uncommon, the most frequent being transient elevated alanine aminotransferase (4.9%), aspartate aminotransferase (2.7%), and alkaline phosphatase (2.3%) levels. Although 98.6% of patients were taking concomitant medications, no clinical or laboratory interactions were observed. The safety profile of fluconazole was compared with those of other antifungal agents, mostly oral polyenes, by using a subset of data from five controlled studies. Side effects were reported by more patients treated with fluconazole (45 of 382; 11.8%) than by those patients treated with comparable agents (25 of 381; 6.6%); vomiting and diarrhea were the most common events in both groups. The incidence and type of treatment-related laboratory abnormalities were similar for the two groups. In conclusion, fluconazole was well tolerated by the pediatric population, many of whom were suffering from severe underlying disease and were taking a variety of concurrent medications. The safety profile of fluconazole in children mirrors the excellent safety profile seen in adults.
A Family of Insertion Mutations between Codons 67 and 70 of Human Immunodeficiency Virus Type 1 Reverse Transcriptase Confer Multinucleoside Analog Resistance
Authors: Larder B. A. , Bloor S. , Kemp S. D. , Hertogs Kurt , Desmet R. L. , Miller V. , Sturmer M. , Staszewski S. , Ren J. , Stammers D. K. , Stuart D. I. , Pauwels R.
Published: October 2018

To investigate the occurrence of multinucleoside analog resistance during therapy failure, we surveyed the drug susceptibilities and genotypes of nearly 900 human immunodeficiency virus type 1 (HIV-1) samples. For 302 of these, the 50% inhibitory concentrations of at least four of the approved nucleoside analogs had fourfold-or-greater increases. Genotypic analysis of the reverse transcriptase (RT)-coding regions from these samples revealed complex mutational patterns, including the previously recognized codon 151 multidrug resistance cluster. Surprisingly, high-level multinucleoside resistance was associated with a diverse family of amino acid insertions in addition to “conventional” point mutations. These insertions were found between RT codons 67 and 70 and were commonly 69Ser-(Ser-Ser) or 69Ser-(Ser-Gly). Treatment history information showed that a common factor for the development of these variants was AZT (3′-azido-3′-deoxythymidine, zidovudine) therapy in combination with 2′,3′-dideoxyinosine or 2′,3′-dideoxycytidine, although treatment patterns varied considerably. Site-directed mutagenesis studies confirmed that 69Ser-(Ser-Ser) in an AZT resistance mutational background conferred simultaneous resistance to multiple nucleoside analogs. The insertions are located in the “fingers” domain of RT. Modelling the 69Ser-(Ser-Ser) insertion into the RT structure demonstrated the profound direct effect that this change is likely to have in the nucleoside triphosphate binding site of the enzyme. Our data highlight the increasing problem of HIV-1 multidrug resistance and underline the importance of continued resistance surveillance with appropriate, sufficiently versatile genotyping technology and phenotypic drug susceptibility analysis.
Inhibitors of DNA Polymerase III as Novel Antimicrobial Agents against Gram-Positive Eubacteria
Authors: Tarantino Paul M. , Zhi Chengxin , Wright George E. , Brown Neal C.
Published: October 2018

6-Anilinouracils are selective inhibitors of DNA polymerase III, the enzyme required for the replication of chromosomal DNA in gram-positive bacteria (N. C. Brown, L. W. Dudycz, and G. E. Wright, Drugs Exp. Clin. Res. 12:555–564, 1986). A new class of 6-anilinouracils based on N-3 alkyl substitution of the uracil ring was synthesized and analyzed for activity as inhibitors of the gram-positive bacterial DNA polymerase III and the growth of gram-positive bacterial pathogens. Favorable in vitro properties of N-3-alkyl derivatives prompted the synthesis of derivatives in which the R group at N-3 was replaced with more-hydrophilic methoxyalkyl and hydroxyalkyl groups. These hydroxyalkyl and methoxyalkyl derivatives displayed

K
i

values in the range from 0.4 to 2.8 μM against relevant gram-positive bacterial DNA polymerase IIIs and antimicrobial activity with MICs in the range from 0.5 to 15 μg/ml against a broad spectrum of gram-positive bacteria, including methicillin-resistant staphylococci and vancomycin-resistant enterococci. Two of these hydrophilic derivatives displayed protective activity in a simple mouse model of lethal staphylococcal infection.
Activity of Telithromycin (HMR 3647) against Anaerobic Bacteria Compared to Those of Eight Other Agents by Time-Kill Methodology
Authors: Credito Kim L. , Ednie Lois M. , Jacobs Michael R. , Appelbaum Peter C.
Published: October 2018

Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO
2
. Macrolide-azalide-ketolide MICs were 0.004 to 32.0 μg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-
Bacteroides fragilis
group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC ≤ 2.0 μg/ml) against all anaerobes except
Peptostreptococcus magnus
and
Bacteroides thetaiotaomicron
, while pristinamycin MICs were 0.06 to 4.0 μg/ml. Amoxicillin-clavulanate had MICs of ≤1.0 μg/ml, while metronidazole was active (MICs, 0.03 to 2.0 μg/ml) against all except
Propionibacterium acnes
. After 48 h at twice the MIC, telithromycin was bactericidal (≥99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred.
TEM-24 Produced by Four Different Species of
Enterobacteriaceae
, Including
Providencia rettgeri
, in a Single Patient
Authors: Marchandin Helene , Carriere Christian , Sirot Danielle , Pierre Helene Jean- , Darbas Helene
Published: October 2018

Four species of members of the family
Enterobacteriaceae
harboring extended-spectrum β-lactamase (ESBL) were recovered in a single patient hospitalized in an intensive care unit. Among these isolates, we describe for the first time an ESBL-producing
Providencia rettgeri
strain. Bacteria from the same species were shown to be genetically related by pulsed-field gel electrophoresis analysis. These strains produced the same TEM derivative ESBL, characterized as TEM-24. This enzyme had the peculiarity of being encoded by a large conjugative plasmid of 180 kb, never previously described for such an ESBL.
Stability of Antibiotics Used for Antibiotic-Lock Treatment of Infections of Implantable Venous Devices (Ports)
Authors: Anthony Thiele Umali , Rubin Lorry G.
Published: October 2018

Antibiotic-lock is a treatment for catheter-related bloodstream infections in which a solution containing heparin and an antibiotic dwells in the lumen of the catheter or port. We tested the stability of vancomycin, cefazolin, ticarcillin-clavulanic acid, ceftazidime, or ciprofloxacin combined with heparin after incubation in vitro at 25 or 37°C for intervals of up to 10 days by bioassay. All the antibiotic solutions except ceftazidime retained ≥90% activity at both 25 and 37°C. Thus, studies of antibiotic-heparin lock solutions with dwell times of up to 10 days are feasible.
In Vitro Susceptibilities of Four
Bartonella bacilliformis
Strains to 30 Antibiotic Compounds
Authors: Sobraquès Mireille , Maurin Max , Birtles Richard J. , Raoult Didier
Published: October 2018

We have evaluated for the first time in vitro antibiotic susceptibilities of four human strains of
Bartonella bacilliformis
, the agent of Carrion’s disease. Our results show that
B. bacilliformis
, like other
Bartonella
species, is highly susceptible to antibiotics, including most beta-lactams, aminoglycosides, chloramphenicol, rifampin, macrolides, tetracyclines, cotrimoxazole, and fluoroquinolones.
Cloning of a
Chryseobacterium
(
Flavobacterium
)
meningosepticum
Chromosomal Gene (
blaA
CME
) Encoding an Extended-Spectrum Class A β-Lactamase Related to the
Bacteroides
Cephalosporinases and the VEB-1 and PER β-Lactamases
Authors: Rossolini Gian Maria , Franceschini Nicola , Lauretti Laura , Caravelli Berardo , Riccio Maria Letizia , Galleni Moreno , Frère Jean-Marie , Amicosante Gianfranco
Published: October 2018

In addition to the BlaB metallo-β-lactamase,
Chryseobacterium
(
Flavobacterium
)
meningosepticum
CCUG 4310 (NCTC 10585) constitutively produces a 31-kDa active-site serine β-lactamase, named CME-1, with an alkaline isoelectric pH. The
blaA
CME
gene that encodes the latter enzyme was isolated from a genomic library constructed in the
Escherichia coli
plasmid vector pACYC184 by screening for cefuroxime-resistant clones. Sequence analysis revealed that the CME-1 enzyme is a new class A β-lactamase structurally divergent from the other members of this class, being most closely related to the VEB-1 (also named CEF-1) and PER β-lactamases and the
Bacteroides
chromosomal cephalosporinases. The
blaA
CME
determinant is located on the chromosome and exhibits features typical of those of
C. meningosepticum
resident genes. The CME-1 protein was purified from an
E. coli
strain that overexpresses the cloned gene via a T7-based expression system by means of an anion-exchange chromatography step followed by a gel permeation chromatography step. Kinetic parameters for several substrates were determined. CME-1 is a clavulanic acid-susceptible extended-spectrum β-lactamase that hydrolyzes most cephalosporins, penicillins, and monobactams but that does not hydrolyze cephamycins and carbapenems. The enzyme exhibits strikingly different kinetic parameters for different classes of β-lactams, with both

K
m

and
k
cat
values much higher for cephalosporins than for penicillins and monobactams. However, the variability of both kinetic parameters resulted in overall similar acylation rates (
k
cat
/

K
m

ratios) for all types of β-lactam substrates.
Efficacious Treatment of Experimental Leishmaniasis with Amphotericin B-Arabinogalactan Water-Soluble Derivatives
Authors: Golenser Jacob , Frankenburg Shoshana , Ehrenfreund Tirtsa , Domb Abraham J.
Published: October 2018

In this study, we tested the efficacy of amphotericin B (AmB)-arabinogalactan (AmB-AG) conjugates for the treatment of experimental leishmaniasis. Chemical conjugation of AmB to a water-soluble, biodegradable, and biocompatible polymer could present many advantages over presently available AmB formulations. Two conjugates were tested, a reduced (rAmB-AG) form and an unreduced (uAmB-AG) form. In vitro, the drug concentrations which lower the values of parasites (for promastigotes) or infected macrophages (for amastigotes) to 50% of the untreated values (ED
50
s) of uAmB-AG and rAmB-AG were 0.19 and 0.34 μg/ml, respectively, for
Leishmania major
promastigotes and 0.17 and 0.31 μg/ml, respectively, for amastigotes. The effect on
Leishmania infantum
-infected macrophages was more marked, with ED
50
s of 0.035 μg/ml for rAmB-AG and 0.027 μg/ml for uAmB-AG. In in vivo experiments, BALB/c mice injected with
L. major
were treated from day 2 onwards on alternate days for 2 weeks. Both conjugates, as well as liposomal AmB (all at 6 mg/kg of body weight) and Fungizone (1 mg/kg), significantly delayed the appearance of lesions compared to that in untreated mice. In addition, both conjugates, but not liposomal AmB, were significantly more effective than Fungizone. Subcutaneous injection of the conjugates (6 mg/kg) was significantly more effective than liposomal AmB in delaying the appearance of lesions. Higher AmB concentrations of up to 12 mg/kg could be administered by this route. When an established infection was treated, uAmB-AG was somewhat more effective than liposomal AmB. In summary, water-soluble polymeric AmB derivatives were found effective and safe for the treatment of leishmanial infections. The conjugates, which are stable and can be produced relatively cheaply (compared to lipid formulations), can be used in the future for the treatment of leishmaniasis infections.
Novel Expansions of the Gene Encoding Dihydropteroate Synthase in Trimethoprim-Sulfamethoxazole-Resistant
Streptococcus pneumoniae
Authors: Padayachee Thanugarani , Klugman Keith P.
Published: October 2018

A study of eight sulfonamide-resistant clinical isolates of
Streptococcus pneumoniae
revealed chromosomal mutations within the gene encoding dihydropteroate synthase that play a role in conferring resistance to sulfamethoxazole. The presence of the
suld
mutation, found previously only in a laboratory mutant, was shown to occur in three of the wild-type clinical isolates. The duplication of Ser
61
, the other previously defined mutation in the dihydropteroate synthase gene of
S. pneumoniae
, was observed in only one of the isolates characterized. We report two previously unidentified amino acid alterations, namely, a duplication of Arg
58
and Pro
59
and an insertion of an arginine residue between Gly
60
and Ser
61
in trimethoprim-sulfamethoxazole-resistant strains. The significance of these mutations was confirmed by site-directed mutagenesis and by the transformation of a susceptible strain of
S. pneumoniae
to sulfamethoxazole resistance. Two resistant isolates did not contain any mutations within the gene encoding dihydropteroate synthase. The results presented suggest the independent generation of resistant mutations among South African clinical isolates. It is also proposed that the mechanism of sulfonamide resistance in
S. pneumoniae
involves the expansion of a specific region within dihydropteroate synthase, which probably forms part of the sulfonamide binding site.
Synergistic Effect of Clindamycin and Atovaquone in Acute Murine Toxoplasmosis
Authors: Djurković-Djaković Olgica , Nikolić Tatjana , Robert-Gangneux Florence , Bobić Branko , Nikolić Aleksandra
Published: October 2018

The effect of clindamycin (CLI) combined with autovaquone (ATO) was examined in a murine model of acute toxoplasmosis. Swiss Webster mice intraperitoneally infected with 10
2
or 10
4
tachyzoites of the RH strain of
Toxoplasma gondii
were perorally treated with either drug alone (for ATO, 5, 25, 50, or 100 mg/kg of body weight/day; for CLI, 25, 50, or 400 mg/kg/day) or both combined (for ATO plus CLI, respectively, 5 plus 25, 25 plus 25, 25 plus 50, 50 plus 50, or 100 plus 400 mg/kg/day) starting with day 1 for 14 days. Survival was monitored during 7 weeks. Residual infection was assessed by a bioassay of representative 4-week survivors and by parasite DNA detection by PCR for representative 7-week survivors. An effect of treatment was shown in all treatment groups compared to untreated control mice (
P
= 0.0000). Among mice infected with 10
2
parasites, ATO and CLI at any dose combination protected significantly more animals than ATO alone (
P
= 0.0000), but compared to CLI alone, given its good effect, the combined drugs were no more effective (
P
> 0.05). For mice infected with 10
4
parasites, the drugs combined at the lowest and highest doses (5 plus 25 and 100 plus 400 mg/kg/day) were, similarly, more effective than ATO alone (
P
= 0.035 and 0.000, respectively) but not than CLI alone (
P
> 0.05). However, treatment with ATO plus CLI at 25 plus 25, 25 plus 50, and 50 plus 50 mg/kg/day protected 20, 33, and 78% of mice, respectively, compared to virtually no survivals among those treated with either drug alone (
P
< 0.0005), thus demonstrating a significant synergistic effect of ATO and CLI against
T. gondii
. Furthermore, the dose of ATO at a given dose of CLI was shown to be critical to the effect. Moreover, the absence of residual infection in some survivors shows the potential of this drug combination to eliminate the parasite.
Acinetobacter baumanniiOxyR Regulates the Transcriptional Response to Hydrogen Peroxide
Authors: Juttukonda Lillian J. , Green Erin R. , Lonergan Zachery R. , Heffern Marie C. , Chang Christopher J. , Skaar Eric P.
Published: October 2018

Acinetobacter baumanniiis a Gram-negative opportunistic pathogen that causes diverse infections, including pneumonia, bacteremia, and wound infections. Due to multiple intrinsic and acquired antimicrobial-resistance mechanisms,A. baumanniiisolates are commonly multidrug resistant, and infections are notoriously difficult to treat.
A Nonfimbrial Adhesin of
Aggregatibacter actinomycetemcomitans
Mediates Biofilm Biogenesis
Authors: Danforth David R. , Tang-Siegel Gaoyan , Ruiz Teresa , Mintz Keith P.
Published: October 2018

Periodontitis is an inflammatory disease caused by polymicrobial biofilms. The periodontal pathogen
Aggregatibacter actinomycetemcomitans
displays two proteinaceous surface structures, the fimbriae and the nonfimbrial extracellular matrix binding protein A (EmaA), as observed by electron microscopy.
Corynebacterium
Species Rarely Cause Orthopedic Infections
Authors: Kalt Fabian , Schulthess Bettina , Sidler Fabian , Herren Sebastian , Fucentese Sandro F. , Zingg Patrick O. , Berli Martin , Zinkernagel Annelies S. , Zbinden Reinhard , Achermann Yvonne
Published: October 2018

Corynebacterium
spp. are rarely considered pathogens, but data on
Corynebacterium
spp.
MostSinorhizobium melilotiExtracytoplasmic Function Sigma Factors Control Accessory Functions
Authors: Lang Claus , Barnett Melanie J. , Fisher Robert F. , Smith Lucinda S. , Diodati Michelle E. , Long Sharon R.
Published: October 2018

Fixed (reduced) soil nitrogen plays a critical role in soil fertility and successful food growth. Much soil fertility relies on symbiotic nitrogen fixation: the bacterial partner infects the host plant roots and reduces atmospheric dinitrogen in exchange for host metabolic fuel, a process that involves complex interactions between the partners mediated by changes in gene expression in each partner. Here we test the roles of a family of 11 extracytoplasmic function (ECF) gene regulatory proteins (sigma factors [σs]) that interact with RNA polymerase to determine if they play a significant role in establishing a nitrogen-fixing symbiosis or in responding to various stresses, including cell envelope stress. We discovered that symbiotic nitrogen fixation occurs even when all 11 of these regulatory genes are deleted, that most ECF sigma factors control accessory functions, and that none of the ECF sigma factors are required to survive envelope stress.
Two distinct histological Richter’s transformations 23 years apart in a patient with chronic lymphocytic leukaemia
Authors: Thebo Umera , Millett Ralph Linwood , Elkon Jacob , Haroun Faysal
Published: October 2018

A 53-year-old man with a 1-year history of chronic lymphocytic leukaemia (CLL) presented with a left bicep mass. Biopsy and staging workup revealed Richter’s transformation (RT) Ann Arbor stage 1E diffuse large B-cell lymphoma in the bicep. The patient was treated with combination chemotherapy with cyclophosphamide, doxorubicin, Vincristine and prednisone followed by site radiation and did well thereafter. His CLL progressed and required treatment on two more occasions 11 and 18 years after his initial diagnosis with fludarabine, Cytoxan and Rituxan and then with bendamustine and rituximab. 23 years after initial presentation, he developed diffuse lymphadenopathy and B-symptoms. A biopsy of an enlarged cervical lymph node demonstrated only CLL for which he was started on ibrutinib. Treatment was shortly discontinued thereafter due to intolerance and worsening symptoms. A second biopsy was performed which revealed concurrent CLL and Hodgkin’s lymphoma representing a second and histologically distinct RT.
Impact of decision aids used during clinical encounters on clinician outcomes and consultation length: a systematic review
Authors: Dobler Claudia Caroline , Sanchez Manuel , Gionfriddo Michael R , Alvarez-Villalobos Neri A , Singh Ospina Naykky , Spencer-Bonilla Gabriela , Thorsteinsdottir Bjorg , Benkhadra Raed , Erwin Patricia J , West Colin P , Brito Juan P , Murad Mohammad Hassan , Montori Victor M
Published: October 2018

Background

Clinicians’ satisfaction with encounter decision aids is an important component in facilitating implementation of these tools. We aimed to determine the impact of decision aids supporting shared decision making (SDM) during the clinical encounter on clinician outcomes.

Methods

We searched nine databases from inception to June 2017. Randomised clinical trials (RCTs) of decision aids used during clinical encounters with an unaided control group were eligible for inclusion. Due to heterogeneity among included studies, we used a narrative evidence synthesis approach.

Results

Twenty-five papers met inclusion criteria including 22 RCTs and 3 qualitative or mixed-methods studies nested in an RCT, together representing 23 unique trials. These trials evaluated healthcare decisions for cardiovascular prevention and treatment (n=8), treatment of diabetes mellitus (n=3), treatment of osteoporosis (n=2), treatment of depression (n=2), antibiotics to treat acute respiratory infections (n=3), cancer prevention and treatment (n=4) and prenatal diagnosis (n=1). Clinician outcomes were measured in only a minority of studies. Clinicians’ satisfaction with decision making was assessed in only 8 (and only 2 of them showed statistically significantly greater satisfaction with the decision aid); only three trials asked if clinicians would recommend the decision aid to colleagues and only five asked if clinicians would use decision aids in the future. Outpatient consultations were not prolonged when a decision aid was used in 9 out of 13 trials. The overall strength of the evidence was low, with the major risk of bias related to lack of blinding of participants and/or outcome assessors.

Conclusion

Decision aids can improve clinicians’ satisfaction with medical decision making and provide helpful information without affecting length of consultation time. Most SDM trials, however, omit outcomes related to clinicians’ perspective on the decision making process or the likelihood of using a decision aid in the future.
Recent advances in the diagnosis and management of pancreatic neuroendocrine tumours
Authors: Hopper Andrew D , Jalal Mustafa , Munir Alia
Published: October 2018

The incidence of pancreatic neuroendocrine tumours (PNET) is rising mainly due to the increased use of cross-sectional imaging. Although many PNETs are asymptomatic and non-functioning, the overall 5-year survival is still less than 50%. In this article, we review the advances in diagnosis, classification and staging of PNET that have evolved with the development of new cross-sectional imaging methods and biopsy techniques. With accurate classification, evidence-based, individualised prognostic outcomes and treatments are able to be given which are also discussed.
Muscle MRI in patients with dysferlinopathy: pattern recognition and implications for clinical trials
Authors: Diaz-Manera Jordi , Fernandez-Torron Roberto , LLauger Jaume , James Meredith K , Mayhew Anna , Smith Fiona E , Moore Ursula R , Blamire Andrew M , Carlier Pierre G , Rufibach Laura , Mittal Plavi , Eagle Michelle , Jacobs Marni , Hodgson Tim , Wallace Dorothy , Ward Louise , Smith Mark , Stramare Roberto , Rampado Alessandro , Sato Noriko , Tamaru Takeshi , Harwick Bruce , Rico Gala Susana , Turk Suna , Coppenrath Eva M , Foster Glenn , Bendahan David , Le Fur Yann , Fricke Stanley T , Otero Hansel , Foster Sheryl L , Peduto Anthony , Sawyer Anne Marie , Hilsden Heather , Lochmuller Hanns , Grieben Ulrike , Spuler Simone , Tesi Rocha Carolina , Day John W , Jones Kristi J , Bharucha-Goebel Diana X , Salort-Campana Emmanuelle , Harms Matthew , Pestronk Alan , Krause Sabine , Schreiber-Katz Olivia , Walter Maggie C , Paradas Carmen , Hogrel Jean-Yves , Stojkovic Tanya , Takeda Shin’ichi , Mori-Yoshimura Madoka , Bravver Elena , Sparks Susan , Bello Luca , Semplicini Claudio , Pegoraro Elena , Mendell Jerry R , Bushby Kate , Straub Volker
Published: October 2018

Background and objective

Dysferlinopathies are a group of muscle disorders caused by mutations in the DYSF gene. Previous muscle imaging studies describe a selective pattern of muscle involvement in smaller patient cohorts, but a large imaging study across the entire spectrum of the dysferlinopathies had not been performed and previous imaging findings were not correlated with functional tests.

Methods

We present cross-sectional T1-weighted muscle MRI data from 182 patients with genetically confirmed dysferlinopathies. We have analysed the pattern of muscles involved in the disease using hierarchical analysis and presented it as heatmaps. Results of the MRI scans have been correlated with relevant functional tests for each region of the body analysed.

Results

In 181 of the 182 patients scanned, we observed muscle pathology on T1-weighted images, with the gastrocnemius medialis and the soleus being the most commonly affected muscles. A similar pattern of involvement was identified in most patients regardless of their clinical presentation. Increased muscle pathology on MRI correlated positively with disease duration and functional impairment.

Conclusions

The information generated by this study is of high diagnostic value and important for clinical trial development. We have been able to describe a pattern that can be considered as characteristic of dysferlinopathy. We have defined the natural history of the disease from a radiological point of view. These results enabled the identification of the most relevant regions of interest for quantitative MRI in longitudinal studies, such as clinical trials.

Clinical trial registration

NCT01676077.
Reproductive outsourcing: an empirical ethics account of cross-border reproductive care in Canada
Authors: Couture Vincent , Drouin Régen , Moutquin Jean-Marie , Monnier Patricia , Bouffard Chantal
Published: October 2018

Cross-border reproductive care (CBRC) can be defined as the movement from one jurisdiction to another for medically assisted reproduction (MAR). CBRC raises many ethical concerns that have been addressed extensively. However, the conclusions are still based on scarce evidence even considering the global scale of CBRC. Empirical ethics appears as a way to foster this ethical reflection on CBRC while attuning it with the experiences of its main actors. To better understand the ‘in and out’ situation of CBRC in Canada, we conducted an ethnographic study taking a ‘critically applied ethics’ approach. This article presents a part of the findings of this research, obtained by data triangulation from qualitative analysis of pertinent literature, participant observation in two Canadian fertility clinics and 40 semidirected interviews. Based on participants’ perceptions, four themes emerged: (1) inconsistencies of the Canadian legal framework; (2) autonomy and the necessity to resort to CBRC; (3) safety and the management of CBRC individual risks; and (4) justice and solidarity. The interaction between these four themes highlights the problematic of ‘reproductive outsourcing’ that characterised the Canadian situation, a system where the controversial aspects of MAR are knowingly pushed outside the borders.