bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emergence and Dissemination of Quinolone-Resistant
Escherichia coli
in the Community
Authors: Garau Javier , Xercavins Mariona , Rodríguez-Carballeira Mónica , Gómez-Vera Josep Ramón , Coll Ignacio , Vidal Dolors , Llovet Teresa , Ruíz-Bremón Ana 
Published: October 2018

ABSTRACT

We studied the evolution of resistance to quinolones in
Escherichia coli
from 1992 to 1997 in Barcelona, Spain. An increasing proportion of quinolone-resistant
E. coli
(QREC) infections was observed. QREC strains were more common in patients with nosocomial infections but also increased in patients with community-acquired infections (9% in 1992 to 17% in 1996). Seventy (12%) of 572 episodes of
E. coli
bacteremia were due to QREC. Factors significantly associated with QREC bacteremia were the presence of underlying disease, recent exposure to antibiotics, and bacteremia of unknown origin. In the multivariate analysis, only prior exposure to antimicrobial agents (
P
< 0.001; odds ratio [OR] = 2), specifically, to quinolones (
P
< 0.001; OR = 14), and the presence of a urinary catheter (
P
< 0.001; OR = 2) were significantly associated with QREC bacteremia. Among 16 QREC isolates from cultures of blood of community origin selected at random, 13 different pulsed-field gel electrophoresis patterns were recognized, showing the genetic diversity of these isolates and in turn indicating the independent emergence of QREC in the community. The prevalence of QREC in the feces of healthy people was unexpectedly high (24% in adults and 26% in children). A survey of the prevalence of QREC of avian and porcine origin revealed a very high proportion of QREC in animal feces (up to 90% of chickens harbored QREC). The high prevalence of QREC in the stools of healthy humans in our area could be linked to the high prevalence of resistant isolates in poultry and pork.
In Vitro Susceptibilities of
Burkholderia mallei
in Comparison to Those of Other Pathogenic
Burkholderia
spp
Authors: Kenny D. J. , Russell P. , Rogers D. , Eley S. M. , Titball R. W. 
Published: October 2018

ABSTRACT

The in vitro antimicrobial susceptibilities of isolates of
Burkholderia mallei
to 16 antibiotics were assessed and compared with the susceptibilities of
Burkholderia pseudomallei
and
Burkholderia cepacia
. The antibiotic susceptibility profile of
B. mallei
resembled that of
B. pseudomallei
more closely than that of
B. cepacia
, which corresponds to their similarities in terms of biochemistry, antigenicity, and pathogenicity. Ceftazidime, imipenem, doxycycline, and ciprofloxacin were active against both
B. mallei
and
B. pseudomallei
. Gentamicin was active against
B. mallei
but not against
B. pseudomallei
. Antibiotics clinically proven to be effective in the treatment of melioidosis may therefore be effective for treating glanders.
Distribution of Insertion Sequence-Like Element IS
1272
and Its Position Relative to Methicillin Resistance Genes in Clinically Important Staphylococci
Authors: Kobayashi Nobumichi , Urasawa Shozo , Uehara Nobuyuki , Watanabe Naoki 
Published: October 2018

ABSTRACT

The distribution of insertion sequence-like element IS
1272
was analyzed for clinical isolates of
Staphylococcus aureus
,
Staphylococcus epidermidis
, and
Staphylococcus haemolyticus
. In each of the staphylococcal species, IS
1272
was detected in both methicillin-resistant (MR) and methicillin-susceptible strains of different genetic types. In MR isolates, IS
1272
was generally located downstream of the truncated
mecR1
gene (Δ
mecR1
), with an identical junction sequence occurring between Δ
mecR1
and IS
1272
, although insertion of an additional gene sequence in the junction sequence was detected in one
S. epidermidis
isolate. These findings suggest that the
mec
element with the rearranged form of
mecR1
(Δ
mecR1
-IS
1272
) has been transmitted to multiple clones of staphylococci.
In Vitro Activities of Gatifloxacin, Two Other Quinolones, and Five Nonquinolone Antimicrobials against Obligately Anaerobic Bacteria
Authors: Schaumann Reiner , Ackermann Grit , Pless Baerbel , Claros Marina C. , Rodloff Arne C. 
Published: October 2018

ABSTRACT
The activity of the new fluoroquinolone gatifloxacin was compared with those of other quinolones and antimicrobial agents of other classes against 294 anaerobes by the broth microdilution technique. For all strains tested, gatifloxacin MICs at which 50 and 90% of the isolates were inhibited were 0.5 and 2 mg/liter, respectively, and were 3 to 4 dilution steps lower than, e.g., ciprofloxacin.
Overexpression of Erg11p by the Regulatable
GAL1
Promoter Confers Fluconazole Resistance in
Saccharomyces cerevisiae
Authors: Kontoyiannis Dimitrios P. , Sagar Namita , Hirschi Kendal D. 
Published: October 2018

ABSTRACT

The contribution of the dosage of target enzyme P-450 14α-demethylase (14αDM) to fluconazole resistance in both
Candida albicans
and
Saccharomyces cerevisiae
remains unclear. Here, we show that overexpression of
Saccharomyces
P-450 14αDM in
S. cerevisiae
, under the control of the regulatable promoter
GAL1
, results in azole resistance.
Activities of Telithromycin (HMR 3647, RU 66647) Compared to Those of Erythromycin, Azithromycin, Clarithromycin, Roxithromycin, and Other Antimicrobial Agents against Unusual Anaerobes
Authors: Goldstein Ellie J. C. , Citron Diane M. , Merriam C. Vreni , Warren Yumi , Tyrrell Kerin 
Published: October 2018

ABSTRACT

The comparative activity of telithromycin (HMR 3647) against 419 human anaerobic isolates was determined by the agar dilution method. At concentrations of ≤0.5 μg/ml, telithromycin was active against
Actinomyces israelii
,
Actinomyces odontolyticus
,
Bacteroides tectum
,
Bacteroides ureolyticus
,
Bacteroides gracilis
(now
Campylobacter gracilis
),
Porphyromonas
spp. (including
Porphyromonas gingivalis
and
Porphyromonas macacae
),
Prevotella intermedia
,
Prevotella heparinolytica
, and almost all
Peptostreptococcus
species. Clostridia showed species and strain variability, often with a biphasic pattern.
Fusobacterium
species, except
Fusobacterium russii
, were relatively resistant.
Distribution of the
cfiA
Gene among
Bacteroides fragilis
Strains in Japan and Relatedness of
cfiA
to Imipenem Resistance
Authors: Yamazoe Kikuo , Kato Naoki , Kato Haru , Tanaka Kaori , Katagiri Yoshihiro , Watanabe Kunitomo 
Published: October 2018

ABSTRACT

The
cfiA
gene, encoding an imipenem-hydrolyzing metallo-β-lactamase produced by
Bacteroides fragilis
, and insertion-like elements were detected by PCR amplification with
B. fragilis
strains isolated in Japan. The
cfiA
gene was found in 1.9 and 4.1% of the imipenem-susceptible
B. fragilis
isolates collected from 1987 to 1988 and from 1992 to 1994, respectively. Insertion-like elements adjacent to the
cfiA
gene were found in all nine metallo-β-lactamase-producing imipenem-resistant strains tested but not in nine
cfiA
-positive strains with no detectable metallo-β-lactamase activity.
Activities of Tobramycin and Six Other Antibiotics against
Pseudomonas aeruginosa
Isolates from Patients with Cystic Fibrosis
Authors: Shawar Ribhi M. , MacLeod David L. , Garber Richard L. , Burns Jane L. , Stapp Jenny R. , Clausen Carla R. , Tanaka S. K. 
Published: October 2018

ABSTRACT

The in vitro activity of tobramycin was compared with those of six other antimicrobial agents against 1,240
Pseudomonas aeruginosa
isolates collected from 508 patients with cystic fibrosis during pretreatment visits as part of the phase III clinical trials of tobramycin solution for inhalation. The tobramycin MIC at which 50% of isolates are inhibited (MIC
50
) and MIC
90
were 1 and 8 μg/ml, respectively. Tobramycin was the most active drug tested and also showed good activity against isolates resistant to multiple antibiotics. The isolates were less frequently resistant to tobramycin (5.4%) than to ceftazidime (11.1%), aztreonam (11.9%), amikacin (13.1%), ticarcillin (16.7%), gentamicin (19.3%), or ciprofloxacin (20.7%). For all antibiotics tested, nonmucoid isolates were more resistant than mucoid isolates. Of 56 isolates for which the tobramycin MIC was ≥16 μg/ml and that were investigated for resistance mechanisms, only 7 (12.5%) were shown to possess known aminoglycoside-modifying enzymes; the remaining were presumably resistant by an incompletely understood mechanism often referred to as “impermeability.”
Activities of a Nitrofurazone-Containing Urinary Catheter and a Silver Hydrogel Catheter against Multidrug-Resistant Bacteria Characteristic of Catheter-Associated Urinary Tract Infection
Authors: Johnson James R. , Delavari Parissa , Azar Miguel 
Published: October 2018

ABSTRACT

The in vitro inhibitory activity of a nitrofurazone-coated urinary catheter (NFC) against 86 recently obtained susceptible and multidrug-resistant (MDR) clinical isolates of
Escherichia coli
,
Klebsiella pneumoniae
,
Citrobacter freundii
,
Staphylococcus aureus
, coagulase-negative
staphylococci
, and
Enterococcus faecium
, which are species implicated in catheter-associated urinary tract infection and which traditionally have been susceptible to nitrofuran derivatives, was determined using an agar diffusion assay. In a subset of these strains, the activity of the NFC was compared with that of a silver hydrogel urinary catheter (SHC), and the durability of each catheter’s inhibitory activity was assessed during serial daily transfers of catheter segments to fresh culture plates. Except for vancomycin-resistant
E. faecium
, the NFC was active against all isolates tested and showed comparable inhibition zones with susceptible and MDR strains of each species. In contrast, the SHC inhibited only certain staphylococci (
P
< 0.01 versus the NFC), and among these strains, the SHC produced smaller inhibition zones than did the NFC (
P
< 0.01). Inhibition was evident for up to 5 days with the NFC, but for only 1 day (if at all) with the SHC (
P
< 0.01). These data document that, for most genera which traditionally have been susceptible to nitrofuran derivatives, the NFC remains active against contemporary MDR isolates. They also demonstrate that the in vitro antibacterial activity of the NFC is markedly superior to that of the SHC in several respects. Thus, the NFC shows promise for clinical use in the current era of MDR bacteria.
Comparative Bacteriostatic and Bactericidal Activities of Cefodizime against
Borrelia burgdorferi
Sensu Lato
Authors: Murgia Rossella , Marchetti Federico , Cinco Marina 
Published: October 2018

ABSTRACT

The MIC and MSC (minimum spirocheticidal concentration) and killing rate for
Borrelia burgdorferi
, the etiological agent of Lyme disease, were assessed for cefodizime in comparison with ceftriaxone, minocycline, azithromycin, roxithromycin, and ciprofloxacin. The range of cefodizime MICs was greater than those of azithromycin and roxithromycin but comparable to those of ceftriaxone and minocycline. The MSCs were 1 to 2 dilutions higher than the MICs of all of the tested compounds. The killing curves of cefodizime and ceftriaxone showed parallel courses. In conclusion, cefodizime exerted an activity comparable to that of ceftriaxone against
B. burgdorferi
.
Variation in the Composition and Pore Function of Major Outer Membrane Pore Protein P2 of
Haemophilus influenzae
from Cystic Fibrosis Patients
Authors: Regelink Annette G. , Dahan David , Möller Lieke V. M. , Coulton James W. , Eijk Paul , Van Ulsen Peter , Dankert Jacob , Van Alphen Loek 
Published: October 2018

ABSTRACT

We investigated the relationship between susceptibility to β-lactam antibiotics and variation in the major outer membrane protein P2 (OmpP2; also called porin) of persistent nonencapsulated
Haemophilus influenzae
isolated from cystic fibrosis patients. Nine OmpP2 variants were selected from two distinct
H. influenzae
strains from two patients extensively treated with β-lactam antibiotics. The variants differed in their susceptibilities to at least two β-lactam antibiotics. By detergent extraction and column chromatography, OmpP2 was purified from two variants that were derived from strain 70 and that differed notably in their susceptibilities to β-lactam antibiotics. The proteins were reconstituted into black lipid membranes for measurement of porin function. OmpP2 from the more resistant isolate (isolate 70b) had a smaller channel conductance than OmpP2 of the more susceptible isolate (isolate 70f). DNA sequencing of
ompP2
of these isolates revealed single nonsynonymous base differences; there were changes in the amino acid sequence corresponding to surface-exposed loops 4, 5, 6, and 8. Changes in loops 4, 5, and 6 were previously shown to result in antigenic differences. Beside these mutations, variants of strain 70 showed additional mutations in loop 1 and nonexposed loop 3. Taken together, our results suggest that in variants of strain 70, nonsynonymous point mutations accumulated both in the sequences of
ompP2
coding for antigen-variable loops and in other loops, notably, loops 1 and 3. The latter changes are suggested to affect the permeability of the porin channel.
Clinical Pharmacokinetics of 1-[((
S
)-2-Hydroxy-2-Oxo-1,4,2-Dioxaphosphorinan-5-yl)methyl]cytosine in Human Immunodeficiency Virus-Infected Patients
Authors: Cundy Kenneth C. , Barditch-Crovo Patricia , Petty Brent G. , Ruby April , Redpath Murphy , Jaffe Howard S. , Lietman Paul S. 
Published: October 2018

ABSTRACT

The pharmacokinetics and bioavailability of 1-[((
S
)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosine (cyclic HPMPC) were examined at four doses in 22 patients with human immunodeficiency virus infection. Two groups of six patients received a single dose of cyclic HPMPC at 1.5 or 3.0 mg/kg of body weight by each of the oral and intravenous routes in a random order with a 2-week washout period between administrations. Additional patients received single intravenous doses of cyclic HPMPC at 5.0 mg/kg (
n
= 6) or 7.5 mg/kg (
n
= 4). Serial serum and urine samples were collected at intervals over 24 h after dosing. The concentrations of cyclic HPMPC and cidofovir in serum and urine samples were determined by validated reverse-phase ion-pairing high-performance liquid chromatography methods with derivatization and fluorescence detection. After intravenous administration of cyclic HPMPC, concentrations of cyclic HPMPC declined in a biexponential manner, with a mean ± standard deviation half-life of 1.09 ± 0.12 h (
n
= 22). The pharmacokinetics of cyclic HPMPC were independent of dose over the dose range of 1.5 to 7.5 mg/kg. The total clearance of cyclic HPMPC from serum and the volume of distribution of intravenous cyclic HPMPC were 198 ± 39.6 ml/h/kg and 338 ± 65.1 ml/kg, respectively (
n
= 22). The renal clearance of cyclic HPMPC (132 ± 27.3 ml/h/kg;
n
= 22) exceeded the creatinine clearance (86.2 ± 16.3 ml/h/kg), indicating active tubular secretion. The cyclic HPMPC excreted in urine in 24 h accounted for 71.3% ± 16.0% of the administered dose. Cidofovir was formed from cyclic HPMPC in vivo with a time to the maximum concentration in serum of 1.64 ± 0.23 h (
n
= 22). Cidofovir levels declined in an apparent monoexponential manner, with a mean terminal half-life of 3.98 ± 1.26 h (
n
= 22). The cidofovir excreted in urine in 24 h accounted for 9.40% ± 2.33% of the administered cyclic HPMPC dose. Exposure to cidofovir after intravenous administration of cyclic HPMPC was dose proportional and was 14.9% of that from an equivalent dose of cidofovir. The present study suggests that intravenous cyclic HPMPC also has a lower potential for nephrotoxicity in humans compared to that of intravenous cidofovir. The oral bioavailabilities of cyclic HPMPC were 1.76% ± 1.48% and 3.10% ± 1.16% with the administration of doses of 1.5 and 3.0 mg/kg, respectively (
n
= 6 per dose). The maximum concentrations of cyclic HPMPC in serum were 0.036 ± 0.021 and 0.082 ± 0.038 μg/ml after the oral administration of doses of 1.5 and 3.0 mg/kg, respectively. Cidofovir reached quantifiable levels in the serum of only one patient for each of the 1.5- and 3.0-mg/kg oral cyclic HPMPC doses.
Characterization and Nucleotide Sequence of CARB-6, a New Carbenicillin-Hydrolyzing β-Lactamase from
Vibrio cholerae
Authors: Choury Danièle , Aubert Gérald , Szajnert Marie-France , Azibi Kemal , Delpech Marc , Paul Gérard 
Published: October 2018

ABSTRACT

A clinical strain of
Vibrio cholerae
non-O1 non-O139 isolated in France produced a new β-lactamase with a pI of 5.35. The purified enzyme, with a molecular mass of 33,000 Da, was characterized. Its kinetic constants show it to be a carbenicillin-hydrolyzing enzyme comparable to the five previously reported CARB β-lactamases and to SAR-1, another carbenicillin-hydrolyzing β-lactamase that has a pI of 4.9 and that is produced by a
V. cholerae
strain from Tanzania. This β-lactamase is designated CARB-6, and the gene for CARB-6 could not be transferred to
Escherichia coli
K-12 by conjugation. The nucleotide sequence of the structural gene was determined by direct sequencing of PCR-generated fragments from plasmid DNA with four pairs of primers covering the whole sequence of the reference CARB-3 gene. The gene encodes a 288-amino-acid protein that shares 94% homology with the CARB-1, CARB-2, and CARB-3 enzymes, 93% homology with the
Proteus mirabilis
N29 enzyme, and 86.5% homology with the CARB-4 enzyme. The sequence of CARB-6 differs from those of CARB-3, CARB-2, CARB-1, N29, and CARB-4 at 15, 16, 17, 19, and 37 amino acid positions, respectively. All these mutations are located in the C-terminal region of the sequence and at the surface of the molecule, according to the crystal structure of the
Staphylococcus aureus
PC-1 β-lactamase.
Efflux Pump-Mediated Quinolone Resistance in
Staphylococcus aureus
Strains Wild Type for
gyrA
,
gyrB
,
grlA
, and
norA
Authors: Muñoz-Bellido Juan Luis , Manzanares M. A. Alonso , Andrés J. A. Martínez , Zufiaurre M. N. Gutiérrez , Ortiz G. , Hernández M. Segovia , García-Rodríguez J. A. 
Published: October 2018

ABSTRACT

Fluoroquinolone efflux was studied in 47
Staphylococcus aureus
clinical strains with MICs of ciprofloxacin (CFX) of ≤2 μg/ml. Forty-three strains were wild type for
gyrA
,
gyrB
, and
grlA
quinolone resistance-determining regions and for
norA
and its promoter region. Forty of these strains (MICs of CFX, 0.1 to 0.2 μg/ml) did not show efflux of fluoroquinolones. Three strains (MICs of CFX, 1 to 2 μg/ml) showed efflux. These results suggest that efflux can appear in
S. aureus
clinical strains in the absence of mutations in
norA
and its promoter.
Activity of a Heat-Induced Reformulation of Amphotericin B Deoxycholate (Fungizone) against
Leishmania donovani
Authors: Petit C. , Yardley V. , Gaboriau F. , Bolard J. , Croft S. L. 
Published: October 2018

ABSTRACT

The heat treatment of amphotericin B deoxycholate (Fungizone), which was previously shown to induce superaggregation and decrease the toxicity of the drug to mammalian cells, increased its activity against
Leishmania donovani
in BALB/c mice, whereas it reduced its toxicity. Heat treatment preserved the activity of Fungizone against
L. donovani
HU3-infected mouse peritoneal macrophages.
Diversification of
Escherichia coli
Expressing an SHV-Type Extended-Spectrum β-Lactamase (ESBL) during a Hospital Outbreak: Emergence of an ESBL-Hyperproducing Strain Resistant to Expanded-Spectrum Cephalosporins
Authors: Pałucha Andrzej , Mikiewicz Barbara , Gniadkowski Marek 
Published: October 2018

ABSTRACT

Twelve SHV-type extended-spectrum β-lactamase (ESBL)-producing
Escherichia coli lac
mutant isolates were recovered in October 1997 from 11 patients of the neonatal ward in a Warsaw hospital. The outbreak was clonal; however, some of the isolates expressed a much higher level of resistance to several β-lactam antibiotics, including expanded-spectrum cephalosporins. This phenotype has been attributed to β-lactamase hyperproduction correlating with the multiplication of ESBL gene copies, as was demonstrated for representative isolates.
Prediction of the Effects of Inoculum Size on the Antimicrobial Action of Trovafloxacin and Ciprofloxacin against
Staphylococcus aureus
and
Escherichia coli
in an In Vitro Dynamic Model
Authors: Firsov Alexander A. , Vostrov Sergey N. , Kononenko Olga V. , Zinner Stephen H. , Portnoy Yury A. 
Published: October 2018

ABSTRACT

The effect of inoculum size (
N
0
) on antimicrobial action has not been extensively studied in in vitro dynamic models. To investigate this effect and its predictability, killing and regrowth kinetics of
Staphylococcus aureus
and
Escherichia coli
exposed to monoexponentially decreasing concentrations of trovafloxacin (as a single dose) and ciprofloxacin (two doses at a 12-h interval) were compared at
N
0
= 10
6
and 10
9
CFU/ml (
S. aureus
) and at
N
0
= 10
6
, 10
7
, and 10
9
CFU/ml (
E. coli
). A series of pharmacokinetic profiles of trovafloxacin and ciprofloxacin with respective half-lives of 9.2 and 4 h were simulated at different ratios of area under the concentration-time curve (AUC) to MIC (in [micrograms × hours/milliliter]/[micrograms/milliliter]): 58 to 466 with trovafloxacin and 116 to 932 with ciprofloxacin for
S. aureus
and 58 to 233 and 116 to 466 for
E. coli
, respectively. Although the effect of
N
0
was more pronounced for
E. coli
than for
S. aureus
, only a minor increase in minimum numbers of surviving bacteria and an almost negligible delay in their regrowth were associated with an increase of the
N
0
for both organisms. The
N
0
-induced reductions of the intensity of the antimicrobial effect (

I
E

, area between control growth and the killing-regrowth curves) were also relatively small. However, the
N
0
effect could not be eliminated either by simple shifting of the time-kill curves obtained at higher
N
0
s by the difference between the higher and lowest
N
0
or by operating with

I
E

s determined within the
N
0
-adopted upper limits of bacterial numbers (

I
E

′s). By using multivariate correlation and regression analyses, linear relationships between

I
E

and log AUC/MIC and log
N
0
related to the respective mean values [(log AUC/MIC)
average
and (log
N
0
)
average
] were established for both trovafloxacin and ciprofloxacin against each of the strains (
r
2
= 0.97 to 0.99). The antimicrobial effect may be accurately predicted at a given AUC/MIC of trovafloxacin or ciprofloxacin and at a given
N
0
based on the relationship

I
E
= a + b

[(log AUC/MIC)/(log AUC/MIC)
average
] −
c
[(log
N
0
)/(log
N
0
)
average
]. Moreover, the relative impacts of AUC/MIC and
N
0
on

I
E

may be evaluated. Since the
c/b
ratios for trovafloxacin and ciprofloxacin against
E. coli
were much lower (0.3 to 0.4) than that for ampicillin-sulbactam as examined previously (1.9), the inoculum effect with the quinolones may be much less pronounced than with the β-lactams. The described approach to the analysis of the inoculum effect in in vitro dynamic models might be useful in studies with other antibiotic classes.