bluuebunny/crossref_metadata_2025 huggingface dataset:
Fosfomycin Alters Lipopolysaccharide-Induced Inflammatory Cytokine Production in Mice
Authors: Matsumoto Tetsuya , Tateda Kazuhiro , Miyazaki Shuichi , Furuya Nobuhiko , Ohno Akira , Ishii Yoshikazu , Hirakata Yoichi , Yamaguchi Keizo
Published: October 2018

To determine the mechanisms of immunomodulating action of fosfomycin (FOF), we examined its effect on the production of inflammatory cytokines in mice injected with lipopolysaccharide (LPS). Treatment with FOF significantly lowered the peak serum levels of tumor necrosis factor alpha and interleukin-1β, indicating that FOF alters inflammatory cytokine production after LPS stimulation.
Comparative In Vitro Activities of Amoxicillin-Clavulanate against Aerobic and Anaerobic Bacteria Isolated from Antral Puncture Specimens from Patients with Sinusitis
Authors: Goldstein Ellie J. C. , Citron Diane M. , Merriam C. Vreni
Published: October 2018

By an agar dilution method, the antimicrobial susceptibilities of antral sinus puncture isolates were studied. Pneumococci were generally susceptible to amoxicillin, azithromycin, and clarithromycin, but 17% of pneumococcal isolates were resistant to cefuroxime.
Haemophilus influenzae
isolates were resistant to amoxicillin and clarithromycin. β-Lactamase production occurred in 69% of
Prevotella
species. One-third of
Peptostreptococcus magnus
isolates were resistant to azithromycin and clarithromycin. Cefuroxime had limited activity against
Prevotella
species and
P. magnus
. Levofloxacin was active against most isolates except peptostreptococci. Amoxicillin-clavulanate was active against all isolates, with the MIC at which 90% of the isolates were inhibited being ≤1 μg/ml.
In Vitro Antibacterial Properties of Pexiganan, an Analog of Magainin
Authors: Ge Yigong , MacDonald Dorothy L. , Holroyd Kenneth J. , Thornsberry Clyde , Wexler Hannah , Zasloff Michael
Published: October 2018

Pexiganan, a 22-amino-acid antimicrobial peptide, is an analog of the magainin peptides isolated from the skin of the African clawed frog. Pexiganan exhibited in vitro broad-spectrum antibacterial activity when it was tested against 3,109 clinical isolates of gram-positive and gram-negative, anaerobic and aerobic bacteria. The pexiganan MIC at which 90% of isolates are inhibited (MIC
90
) was 32 μg/ml or less for
Staphylococcus
spp.,
Streptococcus
spp.,
Enterococcus faecium
,
Corynebacterium
spp.,
Pseudomonas
spp.,
Acinetobacter
spp.,
Stenotrophomonas
spp., certain species of the family
Enterobacteriaceae
,
Bacteroides
spp.,
Peptostreptococcus
spp., and
Propionibacterium
spp. Comparison of the MICs and minimum bactericidal concentrations (MBCs) of pexiganan for 143 isolates representing 32 species demonstrated that for 92% of the isolates tested, MBCs were the same or within 1 twofold difference of the MICs, consistent with a bactericidal mechanism of action. Killing curve analysis showed that pexiganan killed
Pseudomonas aeruginosa
rapidly, with 10
6
organisms/ml eliminated within 20 min of treatment with 16 μg of pexiganan per ml. No evidence of cross-resistance to a number of other antibiotic classes was observed, as determined by the equivalence of the MIC
50
s and the MIC
90
s of pexiganan for strains resistant to oxacillin, cefazolin, cefoxitin, imipenem, ofloxacin, ciprofloxacin, gentamicin, and clindamicin versus those for strains susceptible to these antimicrobial agents. Attempts to generate resistance in several bacterial species through repeated passage with subinhibitory concentrations of pexiganan were unsuccessful. In conclusion, pexiganan exhibits properties in vitro which make it an attractive candidate for development as a topical antimicrobial agent.
9-[2-(Phosphonomethoxy)propyl]adenine (PMPA) Therapy Prolongs Survival of Infant Macaques Inoculated with Simian Immunodeficiency Virus with Reduced Susceptibility to PMPA
Authors: van Rompay Koen K. A. , Cherrington Julie M. , Marthas Marta L. , Lamy Patrick D. , Dailey Peter J. , Canfield Don R. , Tarara Ross P. , Bischofberger Norbert , Pedersen Niels C.
Published: October 2018

Simian immunodeficiency virus (SIV) infection of newborn rhesus macaques is a useful animal model of human immunodeficiency virus infection for the study of the emergence and clinical implications of drug-resistant viral mutants. We previously demonstrated that SIV-infected infant macaques receiving prolonged treatment with 9-[2-(phosphonomethoxy)propyl]adenine (PMPA) developed viral mutants with fivefold reduced susceptibility to PMPA in vitro and that the development of these mutants was associated with the development of a K65R mutation and additional compensatory mutations in reverse transcriptase (RT). To study directly the virulence and clinical implications of these SIV mutants, two uncloned SIV
mac
isolates with similar fivefold reduced in vitro susceptibilities to PMPA but distinct RT genotypes, SIV
mac055
(K65R, N69T, R82K A158S, S211N) and SIV
mac385
(K65R, N69S, I118V), were each inoculated intravenously into six newborn rhesus macaques; 3 weeks later, three animals of each group were started on PMPA treatment. All six untreated animals developed persistently high levels of viremia and fatal immunodeficiency within 4 months. In contrast, the six PMPA-treated animals, despite having persistently high virus levels, survived significantly longer: 5 to 9 months for the three SIV
mac055
-infected infants and ≥21 months for the three SIV
mac385
-infected infants. Virus from only one untreated animal demonstrated reversion to wild-type susceptibility and loss of the K65R mutation. In several other animals, additional RT mutations, including K64R and Y115F, were detected, but the biological role of these mutations is unclear since they did not affect the in vitro susceptibility of the virus to PMPA. In conclusion, this study demonstrates that although SIV
mac
mutants with the PMPA-selected K65R mutation in RT were highly virulent, PMPA treatment still offered strong therapeutic benefits. These results suggest that the potential emergence of HIV mutants with reduced susceptibility to PMPA in patients during prolonged PMPA therapy may not eliminate its therapeutic benefits.
Antiviral Effect of Hyperthermic Treatment in Rhinovirus Infection
Authors: Conti C. , de Marco A. , Mastromarino P. , Tomao P. , Santoro M. G.
Published: October 2018

Human rhinoviruses (HRV) are recognized as the major etiologic agents of the common cold. Starting from the observation that local hyperthermic treatment is beneficial in patients with natural and experimental common colds, we have studied the effect of brief hyperthermic treatment (HT) on HRV replication in HeLa cells. We report that a 20-min HT at 45°C is effective in suppressing HRV multiplication by more than 90% when applied at specific stages of the virus replication cycle. Synthesis of virus proteins is not affected by HT, indicating that the target for treatment is a posttranslational event. The antiviral effect is a transient cell-mediated event and is associated with the synthesis of the 70-kDa heat shock protein hsp70. Unlike poliovirus, rhinovirus infection does not inhibit the expression of hsp70 induced by heat. The possibility that hsp70 could play a role in the control of rhinovirus replication is suggested by the fact that a different class of HSP inducers, the cyclopentenone prostaglandins PGA
1
and Δ
12
-PGJ
2
, were also effective in inhibiting HRV replication in HeLa cells. Inhibition of hsp70 expression by actinomycin D prevented the antiviral activity of prostaglandins in HRV-infected cells. These results indicate that the beneficial effect of respiratory hyperthermia may be mediated by the induction of a cytoprotective heat shock response in rhinovirus-infected cells.
The Immune Response Modifier Imiquimod Requires STAT-1 for induction of Interferon, Interferon-Stimulated Genes, and Interleukin-6
Authors: Bottrel Renata L. A. , Yang Yi-Li , Levy David E. , Tomai Mark , Reis Luiz F. L.
Published: October 2018

Imiquimod is an oral inducer of interferon (IFN) and several other proinflammatory cytokines and has been successfully used topically as an antiviral agent for the treatment of genital warts. We have investigated the molecular mechanisms by which imiquimod induces the expression of IFNs, IFN-stimulated genes (ISGs), and proinflammatory cytokines in vivo, using mice deficient in various components of the IFN signaling system. Mice deficient in the transcription factor interferon regulatory factor 1 (IRF-1) or in the serine/threonine protein kinase PKR responded normally to imiquimod, producing high levels of circulating IFN and induction of several ISGs. On the other hand, when mice deficient in STAT-1 were treated, a 32-fold reduction in the level of circulating IFN was observed, together with a lack of induction of 2-5 oligo adenylate synthetase (2-5 OAS) and IRF-1 genes. Interestingly, there was also a lack of induction of interleukin-6 (IL-6) gene expression, although tumor necrosis factor was induced and readily detected in serum. In mice deficient in the type I IFN receptor, imiquimod induced levels of IFN similar to those in control mice, but again, neither 2-5 OAS, IRF-1, nor IL-6 genes were induced in mutant mice. Our results suggest that STAT-1 plays a critical role in the mechanism of gene activation by imiquimod. Moreover, induction of IL-6 gene expression appears to be dependent on components of the IFN signaling cascade.
Pharmacokinetics of β-
l
-2′,3′-Dideoxy-5-Fluorocytidine in Rhesus Monkeys
Authors: Martin Lee T. , Cretton-Scott Erika , Schinazi Raymond F. , Zhou Xiao-Jian , McClure Harold M. , Mathe Christophe , Gosselin Gilles , Imbach Jean-Louis , Sommadossi Jean-Pierre
Published: October 2018

β-
l
-2′,3′-Dideoxy-5-fluorocytidine (β-
l
-FddC), a novel cytidine analog with an unnatural β-
l
sugar configuration, has been demonstrated by our group and others to exhibit highly selective in vitro activity against human immunodeficiency virus types 1 and 2 and hepatitis B virus. This encouraging in vitro antiviral activity prompted us to assess its pharmacokinetics in rhesus monkeys. Three monkeys were administered an intravenous dose of [
3
H]β-L-FddC at 5 mg/kg of body weight. Following a 3-month washout period, an equivalent oral dose was administered. Plasma and urine samples were collected at various times for up to 24 h after dosing, and drug levels were quantitated by high-pressure liquid chromatography. Pharmacokinetic parameters were obtained on the basis of a two-compartment open model with a first-order elimination from the central compartment. After intravenous administration, the mean peak concentration in plasma (
C
max
) was 29.8 ± 10.5 μM. Total clearance, steady-state volume of distribution, terminal-phase plasma half-life (
t
1/2β
), and mean residence time were 0.7 ± 0.1 liters/h/kg, 1.3 ± 0.1 liters/kg, 1.8 ± 0.2 h, and 1.9 ± 0.2 h, respectively. Approximately 47% ± 16% of the intravenously administered radioactivity was recovered in the urine as the unchanged drug with no apparent metabolites. β-
l
-FddC exhibited a
C
max
of 3.2 μM after oral administration, with a time to peak drug concentration of approximately 1.5 h and a
t
1/2
of 2.2 h. One monkey in the oral administration arm of the study had a significant delay in the absorption of the aqueous administered dose. The absolute bioavailability of orally administered β-
l
-FddC ranged from 56 to 66%.
Comparison of Activities of Broad-Spectrum β-Lactam Compounds against 1,128 Gram-Positive Cocci Recently Isolated in Cancer Treatment Centers
Authors: Diekema Daniel J. , Coffman Stacy L. , Marshall Steven A. , Beach Mondell L. , Rolston Kenneth V. I. , Jones Ronald N.
Published: October 2018

We report the in vitro activities of broad-spectrum β-lactam antimicrobials tested against 1,128 gram-positive pathogens recently isolated from cancer patients. Cefepime and imipenem were more active than ceftazidime and ceftriaxone against these organisms. Only vancomycin demonstrated reliable activity against oxacillin-resistant staphylococci,
Enterococcus
spp., and
Corynebacterium
spp. The spectrum of gram-positive organisms against which cefepime and imipenem have activity provides an advantage over ceftazidime as empiric therapy for cancer patients, potentially reducing the need for the empiric addition of glycopeptides.
Sequences of the Genes for the TEM-20, TEM-21, TEM-22, and TEM-29 Extended-Spectrum β-Lactamases
Authors: Arlet Guillaume , Goussard Sylvie , Courvalin Patrice , Philippon Alain
Published: October 2018

The sequences of the
bla
TEM
genes encoding TEM-20, TEM-21, TEM-22, and TEM-29 extended-spectrum β-lactamases were determined. Analysis of the deduced amino acid sequences indicated that TEM-20 and TEM-29 were derived from TEM-1 and that TEM-21 and TEM-22 were derived from TEM-2. The substitutions involved were Ser-238 and Thr-182 for TEM-20; His-164 for TEM-29; Lys-104, Arg-153, and Ser-238 for TEM-21; and Lys-104, Gly-237, and Ser-238 for TEM-22. The promoter region of the
bla
TEM-22
gene was identical to that of
bla
TEM-3
. High-level production of TEM-20 could result from a 135-bp deletion which combined the −35 region of the
Pa
promoter with the −10 region of the
P3
promoter and a G→T transition in the latter motif.
Potentiation of Isoniazid Activity againstMycobacterium tuberculosisby Melatonin
Authors: Wiid Ian , Hoal-van Helden Eileen , Hon Dinie , Lombard Carl , van Helden Paul
Published: October 2018

The limited number of effective antituberculosis drugs available necessitates optimizing current treatments. We show that melatonin, which is synthesized in the pineal gland, can cause at least a threefold increase in the efficacy of isoniazid. This suggests that tuberculosis chemotherapy can be improved by innate molecules such as melatonin.
Pseudomonas aeruginosa
: a Survey of Resistance in 136 Hospitals in Spain
Authors: Bouza E. , Garcia-Garrote F. , Cercenado E. , Marin M. , Diaz M. S.
Published: October 2018

We carried out a nationwide study with all of the isolates of
Pseudomonas aeruginosa
collected in a week in 136 hospitals in Spain. The data on 1,014 isolates included resistance to the following antimicrobials: piperacillin-tazobactam, 7%; meropenem, 8%; amikacin, 9%; tobramycin, 10%; piperacillin, 10%; ticarcillin, 13%; imipenem, 14%; ceftazidime, 15%; cefepime, 17%; ciprofloxacin, 23%; aztreonam, 23%; ofloxacin, 30%; gentamicin, 31%. The most frequent serotypes were O:1 (25.1%), O:4 (21.6%), and O:11 (11.3%).
In Vitro Activities of Ketolides HRM 3647 and HRM 3004, Levofloxacin, and Other Quinolones and Macrolides against
Neisseria
spp. and
Moraxella catarrhalis
Authors: Sáez-Nieto J. A. , Vázquez J. A.
Published: October 2018

In vitro activities of the ketolides HRM 3647 and HRM 3004 against pathogenic
Neisseria gonorrhoeae
and
N. meningitidis
, saprophytic
Neisseria
isolates, and
Moraxella catarrhalis
were determined. The comparison of ketolide activities with those of the other macrolides shows a much better activity in the majority of species, with macrolide MICs at which 90% of the isolates are inhibited between 8- and 10-fold higher.
Efficacies of Albendazole Sulfoxide and Albendazole Sulfone against In Vitro-Cultivated
Echinococcus multilocularis
Metacestodes
Authors: Ingold Katrin , Bigler Peter , Thormann Wolfgang , Cavaliero Tania , Gottstein Bruno , Hemphill Andrew
Published: October 2018

The metacestode stage of
Echinococcus multilocularis
is the causative agent of alveolar echinococcosis (AE), a parasitic disease affecting the liver, with occasional metastasis into other organs. Benzimidazole carbamate derivatives such as mebendazole and albendazole are currently used for chemotherapeutic treatment of AE. Albendazole is poorly resorbed and is metabolically converted to its main metabolite albendazole sulfoxide, which is believed to be the active component, and further to albendazole sulfone. Chemotherapy with albendazole has been shown to have a parasitostatic rather than a parasitocidal effect; it is not effective in all cases, and the recurrence rate is rather high once chemotherapy is stopped. Thus, development of new means of chemotherapy of AE is needed. This could include modifications of benzimidazoles and elucidiation of the respective biological pathways. In this study we performed in vitro drug treatment of
E. multilocularis
metacestodes with albendazole sulfoxide and albendazole sulfone. High-performance liquid chromatography analysis of vesicle fluids showed that the drugs were taken up rapidly by the parasite. Transmission electron microscopic investigation of parasite tissues and nuclear magnetic resonance spectroscopy of vesicle fluids demonstrated that albendazole sulfoxide and albendazole sulfone had similar effects with respect to parasite ultrastructure and changes in metabolites in vesicle fluids. This study shows that the in vitro cultivation model presented here provides an ideal first-round test system for screening of antiparasite drugs.
In Vitro Anti-
Helicobacter pylori
Activities of New Rifamycin Derivatives, KRM-1648 and KRM-1657
Authors: Akada Junko K. , Shirai Mutsunori , Fujii Kenji , Okita Kiwamu , Nakazawa Teruko
Published: October 2018

The new rifamycin derivatives KRM-1657 and KRM-1648 were evaluated for their in vitro antimicrobial activities against 44 strains of
Helicobacter pylori
. Although the drugs were not very active against other gram-negative bacteria, the MICs at which 90% of isolates are inhibited for these drugs were lower (0.002 and 0.008 μg/ml, respectively) than those of amoxicillin and rifampin for
H. pylori
. Time-kill studies revealed that the bactericidal activities of these agents were due to cell lysis. The results presented here indicate that these new rifamycin derivatives may be useful for the eradication of
H. pylori
infections.
In Vitro and In Vivo Antimicrobial Activities of T-3811ME, a Novel Des-F(6)-Quinolone
Authors: Takahata Masahiro , Mitsuyama Junichi , Yamashiro Yoshiko , Yonezawa Minoru , Araki Harumi , Todo Yozo , Minami Shinzaburo , Watanabe Yasuo , Narita Hirokazu
Published: October 2018

The in vitro and in vivo activities of T-3811ME, a novel des-F(6)-quinolone, were evaluated in comparison with those of some fluoroquinolones, including a newly developed one, trovafloxacin. T-3811, a free base of T-3811ME, showed a wide range of antimicrobial spectra, including activities against
Chlamydia trachomatis
,
Mycoplasma pneumoniae
, and
Mycobacterium tuberculosis
. In particular, T-3811 exhibited potent activity against various gram-positive cocci, with MICs at which 90% of the isolates are inhibited (MIC
90
s) of 0.025 to 6.25 μg/ml. T-3811 was the most active agent against methicillin-resistant
Staphylococcus aureus
and streptococci, including penicillin-resistant
Streptococcus pneumoniae
(PRSP). T-3811 also showed potent activity against quinolone-resistant gram-positive cocci with GyrA and ParC (GrlA) mutations. The activity of T-3811 against members of the family
Enterobacteriaceae
and nonfermentative gram-negative rods was comparable to that of trovafloxacin. In common with other fluoroquinolones, T-3811 was highly active against
Haemophilus influenzae
,
Moraxella catarrhalis
, and
Legionella
sp., with MIC
90
s of 0.0125 to 0.1 μg/ml. T-3811 showed a potent activity against anaerobic bacteria, such as
Bacteroides fragilis
and
Clostridium difficile
. T-3811 was the most active agent against
C. trachomatis
(MIC, 0.008 μg/ml) and
M. pneumoniae
(MIC
90
, 0.0313 μg/ml). The activity of T-3811 against
M. tuberculosis
(MIC
90
, 0.0625 μg/ml) was potent and superior to that of trovafloxacin. In experimental systemic infection with a GrlA mutant of
S. aureus
and experimental pneumonia with PRSP in mice, T-3811ME showed excellent therapeutic efficacy in oral and subcutaneous administrations.
Efficacy of Microencapsulated Rifampin in
Mycobacterium tuberculosis
-Infected Mice
Authors: Quenelle Debra C. , Staas Jay K. , Winchester Gary A. , Barrow Esther L. W. , Barrow William W.
Published: October 2018

Rifampin is a first-line drug useful in the treatment of tuberculosis. By using biocompatible polymeric excipients of lactide and glycolide copolymers, two microsphere formulations were developed for targeted and sustained delivery of rifampin, with minimal dosing. A small-microsphere formulation, with demonstrated ability to inhibit intracellularly replicating
Mycobacterium tuberculosis
H37Rv, was tested along with a large-microsphere formulation in an infected mouse model. Results revealed that by using a single treatment of the large-microsphere formulation, it was possible to achieve a significant reduction in
M. tuberculosis
H37Rv CFUs in the lungs of mice by 26 days postinfection. A combination of small (given as two injections on day 0 and day 7) and large (given as one injection at day 0) rifampin-loaded microsphere formulations resulted in significant reductions in CFUs in the lungs by 26 days, achieving a 1.23 log
10
reduction in CFUs. By comparison, oral treatment with 5, 10, or 20 mg of rifampin/kg of body weight, administered every day, resulted in a reduction of 0.42, 1.7, or 1.8 log
10
units, respectively. Thus the microsphere formulations, administered in one or two doses, were able to achieve results in mice similar to those obtained with a daily drug regimen within the range of the highest clinically tolerated dosage in humans. These results demonstrate that microsphere formulations of antimycobacterial drugs such as rifampin can be used for therapy of tuberculosis with minimal dosing.
Mechanism of the Intracellular Killing and Modulation of Antibiotic Susceptibility ofListeria monocytogenesin THP-1 Macrophages Activated by Gamma Interferon
Authors: Ouadrhiri Youssef , Scorneaux Bernard , Sibille Yves , Tulkens Paul M.
Published: October 2018

Listeria monocytogenes, a facultative intracellular pathogen, readily enters cells and multiplies in the cytosol after escaping from phagosomal vacuoles. Macrophages exposed to gamma interferon, one of the main cellular host defenses againstListeria, become nonpermissive for bacterial growth while containingListeriain the phagosomes. Using the human myelomonocytic cell line THP-1, we show that the combination ofl-monomethyl arginine and catalase restores bacterial growth without affecting the phagosomal containment ofListeria. A previous report (B. Scorneaux, Y. Ouadrhiri, G. Anzalone, and P. M. Tulkens, Antimicrob. Agents Chemother. 40:1225–1230, 1996) showed that intracellularListeriawas almost equally sensitive to ampicillin, azithromycin, and sparfloxacin in control cells but became insensitive to ampicillin and more sensitive to azithromycin and sparfloxacin in gamma interferon-treated cells. We show here that these modulations of antibiotic activity are largely counteracted byl-monomethyl arginine and catalase. In parallel, we show that gamma interferon enhances the cellular accumulation of azithromycin and sparfloxacin, an effect which is not reversed by addition ofl-monomethyl arginine and catalase and which therefore cannot account for the increased activity of these antibiotics in gamma interferon-treated cells. We conclude that (i) the control exerted by gamma interferon on intracellular multiplication ofListeriain THP-1 macrophages is dependent on the production of nitric oxide and hydrogen peroxide; (ii) intracellularListeriamay become insensitive to ampicillin in macrophages exposed to gamma interferon because the increase in reactive oxygen and nitrogen intermediates already controls bacterial growth; and (iii) azithromycin and still more sparfloxacin cooperate efficiently with gamma interferon, one of the main cellular host defenses inListeriainfection.
Comparison of In Vitro Activity of Liposomal Nystatin against
Aspergillus
Species with Those of Nystatin, Amphotericin B (AB) Deoxycholate, AB Colloidal Dispersion, Liposomal AB, AB Lipid Complex, and Itraconazole
Authors: Oakley Karen L. , Moore Caroline B. , Denning David W.
Published: October 2018

We compared the in vitro activity of liposomal nystatin (Nyotran) with those of other antifungal agents against 60
Aspergillus
isolates. Twelve isolates were itraconazole resistant. For all isolates, geometric mean (GM) MICs (micrograms per milliliter) were 2.30 for liposomal nystatin, 0.58 for itraconazole, 0.86 for amphotericin B (AB) deoxycholate, 9.51 for nystatin, 2.07 for liposomal AB, 2.57 for AB lipid complex, and 0.86 for AB colloidal dispersion.
Aspergillus terreus
(GM, 8.72 μg/ml; range, 8 to 16 μg/ml) was significantly less susceptible to all of the polyene drugs than all other species (
P
= 0.0001).
An SHV-Derived Extended-Spectrum β-Lactamase in
Pseudomonas aeruginosa
Authors: Naas Thierry , Philippon Laurence , Poirel Laurent , Ronco Esthel , Nordmann Patrice
Published: October 2018

A clinical isolate of
Pseudomonas aeruginosa
RP-1 produced the extended-spectrum β-lactamase (ESBL) SHV-2a. Its gene was expressed from a composite promoter made of the −35 region derived from the left inverted repeat of IS
26
and the −10 region from the
bla
SHV-2a
promoter itself. The DNA sequences immediately surrounding
bla
SHV-2a
were homologous to plasmid pMPA2a from
Klebsiella pneumoniae
KpZU-3, while further away and 3′ to the
bla
SHV-2a
gene, a sequence corresponding to the left end of Tn
1721
was detected, thus indicating a likely enterobacterial origin of this ESBL gene.
Antimicrobial Activities and Postantibiotic Effects of Clarithromycin, 14-Hydroxy-Clarithromycin, and Azithromycin in Epithelial Cell Lining Fluid against Clinical Isolates ofHaemophilus influenzaeandStreptococcus pneumoniae
Authors: Bergman Kimberly L. , Olsen Keith M. , Peddicord Tom E. , Fey Paul D. , Rupp Mark E.
Published: October 2018

The antimicrobial activity of concentrations of selected macrolides found in epithelial cell lining fluid was investigated. Clarithromycin demonstrated greater potency and a significantly longer postantibiotic effect (PAE) than azithromycin againstStreptococcus pneumoniae. Azithromycin displayed greater potency, faster killing, and a longer PAE than clarithromycin againstHaemophilus influenzae. Drug concentrations in epithelial cell lining fluid similar to those found in tissue did not improve the synergistic potential of 14-hydroxy-clarithromycin and indicate that a maximal PAE may exist despite increasing concentrations of drug.
Sensitivity of Spermidine-Deficient
Saccharomyces cerevisiae
to Paromomycin
Authors: Balasundaram David , Tabor Celia White , Tabor Herbert
Published: October 2018

Spermidine-deficient
Saccharomyces cerevisiae
cells are much more sensitive to paromomycin than nondeficient cells, resulting in cessation of growth and cell death.
Amphotericin B in Children with Malignant Disease: a Comparison of the Toxicities and Pharmacokinetics of Amphotericin B Administered in Dextrose versus Lipid Emulsion
Authors: Nath Christa E. , Shaw Peter J. , Gunning Robyn , McLachlan Andrew J. , Earl John W.
Published: October 2018

In a prospective, randomized clinical trial, the toxicity of 1 mg of amphotericin B (AmB) per kg of body weight per day infused in 5% dextrose was compared with that of AmB infused in lipid emulsion in children with malignant disease. In an analysis of 82 children who received a full course of 6 days or more of AmB (117 courses), it was shown that there were significant increases in plasma urea and creatinine concentrations and in potassium requirement after 6 days of therapy with both AmB infused in dextrose and AmB infused in lipid emulsion, with there being no difference between the two methods of AmB administration. An intent-to-treat comparison of the numbers of courses affected by acute toxicity (fever, rigors) and chronic toxicity (nephrotoxicity) also indicated that there was no significant difference between AmB infused in dextrose (78 courses) and AmB infused in lipid emulsion (84 courses). The pharmacokinetics of AmB were investigated in 20 children who received AmB in dextrose and 15 children who received AmB in lipid emulsion. Blood samples were collected up to 24 h after administration of the first dose, and the concentration of AmB in plasma was analyzed by a high-performance liquid chromatography assay. The clearance (CL) of AmB in dextrose (0.039 ± 0.016 liter · h
−1
· kg
−1
) was significantly lower (
P
< 0.005) than the CL of AmB in lipid emulsion (0.062 ± 0.024 liter · h
−1
· kg
−1
). The steady-state volume of distribution for AmB in dextrose (0.83 ± 0.33 liter · kg
−1
) was also significantly lower (
P
< 0.005) than that for AmB in lipid emulsion (1.47 ± 0.77 liter · kg
−1
). Although AmB in lipid emulsion is apparently cleared faster and distributes more widely than AmB in dextrose, this study did not reveal any significant advantage with respect to safety and tolerance in the administration of AmB in lipid emulsion compared to its administration in dextrose in children with malignant disease.
Azithromycin versus Ciprofloxacin for Treatment of Uncomplicated Typhoid Fever in a Randomized Trial in Egypt That Included Patients with Multidrug Resistance
Authors: Girgis Nabil I. , Butler Thomas , Frenck Robert W. , Sultan Yehia , Brown Forrest M. , Tribble David , Khakhria Rasik
Published: October 2018

To compare clinical and bacteriological efficacies of azithromycin and ciprofloxacin for typhoid fever, 123 adults with fever and signs of uncomplicated typhoid fever were entered into a randomized trial. Cultures of blood were positive for
Salmonella typhi
in 59 patients and for
S. paratyphi
A in 3 cases; stool cultures were positive for
S. typhi
in 11 cases and for
S. paratyphi
A in 1 case. Multiple-drug resistance (MDR; resistance to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole) was present in isolates of 21 of 64 patients with positive cultures. Of these 64 patients, 36 received 1 g of azithromycin orally once on the first day, followed by 500 mg given orally once daily on the next 6 days; 28 patients received 500 mg of ciprofloxacin orally twice daily for 7 days. Blood cultures were repeated on days 4 and 10 after the start of therapy, and stool cultures were done on days 4, 10, and 28 after the start of therapy. All patients in both groups improved during therapy and were cured. Defervescence (maximum daily temperatures of ≤38°C) occurred at the following times [mean ± standard deviation (range)] after the start of therapy: 3.8 ± 1.1 (2 to 7) days with azithromycin and 3.3 ± 1.0 (1 to 5) days with ciprofloxacin. No relapses were detected. Cultures of blood and stool during and after therapy were negative in all cases, except for one patient treated with azithromycin who had a positive blood culture on day 4. These results indicated that azithromycin and ciprofloxacin were similarly effective, both clinically and bacteriologically, against typhoid fever caused by both sensitive organisms and MDR
S. typhi
.
In Vitro Susceptibilities of
Candida
and
Cryptococcus neoformans
Isolates from Blood Cultures of Neutropenic Patients
Authors: Hoban Daryl J. , Zhanel George G. , Karlowsky James A.
Published: October 2018

Fluconazole-resistant
Candida albicans
and intrinsically fluconazole-resistant
Candida
species have been reported as bloodstream isolates. However, an association between the isolation of fluconazole-resistant
Candida
from the bloodstream and patient risk factors for fungemia has not been established. The purpose of this study was to determine the prevalence of fluconazole resistance in bloodstream isolates of
Candida
species and
Cryptococcus neoformans
collected from patients with neutropenia, one of the most important risk factors for fungemia. MICs of voriconazole, fluconazole, itraconazole, ketoconazole, amphotericin B, and flucytosine were determined by the National Committee for Clinical Laboratory Standards M27-A method (1997). Voriconazole, on a per-weight basis, was the most active azole tested. Fluconazole resistance (MIC ≥ 64 μg/ml) was not identified in any of the
C. albicans
(
n
= 513),
Candida parapsilosis
(
n
= 78),
Candida tropicalis
(
n
= 62), or
C. neoformans
(
n
= 38) isolates tested.
Linezolid Activity Compared to Those of Selected Macrolides and Other Agents against Aerobic and Anaerobic Pathogens Isolated from Soft Tissue Bite Infections in Humans
Authors: Goldstein Ellie J. C. , Citron Diane M. , Merriam C. Vreni
Published: October 2018

Linezolid was tested against 420 aerobes and anaerobes, including 148Pasteurellaisolates, by an agar dilution method. Linezolid was active against allPasteurella multocidasubsp.multocidaandP. multocidasubsp.septicaisolates and mostPasteurella canis,Pasteurella dagmatis, andPasteurella stomatisisolates. The MIC was ≤2 μg/ml for staphylococci, streptococci, EF-4b,Weeksella zoohelcum,Fusobacterium nucleatum, other fusobacteria,Porphyromonasspp.,Prevotellaspp., peptostreptococci, and almost allBacteroides tectumisolates.
Effect of Azithromycin plus Rifampin versus That of Azithromycin Alone on the Eradication of
Chlamydia pneumoniae
from Lung Tissue in Experimental Pneumonitis
Authors: Wolf Katerina , Malinverni Raffaele
Published: October 2018

Azithromycin, doxycycline, and rifampin, alone or in combination, were tested in vitro against
Chlamydia pneumoniae
AR-39. The combination of azithromycin plus rifampin showed the strongest activity and produced higher rates of eradication of
C. pneumoniae
from lung tissues than azithromycin alone in experimental mouse pneumonitis.
Salt-Resistant Alpha-Helical Cationic Antimicrobial Peptides
Authors: Friedrich Carol , Scott Monisha G. , Karunaratne Nedra , Yan Hong , Hancock Robert E. W.
Published: October 2018

Analogues based on the insect cecropin–bee melittin hybrid peptide (CEME) were studied and analyzed for activity and salt resistance. The new variants were designed to have an increase in amphipathic α-helical content (CP29 and CP26) and in overall positive charge (CP26). The α-helicity of these peptides was demonstrated by circular dichroism spectroscopy in the presence of liposomes. CP29 was shown to have activity against gram-negative bacteria that was similar to or better than those of the parent peptides, and CP26 had similar activity. CP29 had cytoplasmic membrane permeabilization activity, as assessed by the unmasking of cytoplasmic β-galactosidase, similar to that of CEME and its more positively charged derivative named CEMA, whereas CP26 was substantially less effective. The activity of the peptides was not greatly attenuated by an uncoupler of membrane potential, carbonyl cyanide-
m
-chlorophenylhydrazone. The tryptophan residue in position 2 was shown to be necessary for interaction with cell membranes, as demonstrated by a complete lack of activity in the peptide CP208. Peptides CP29, CEME, and CEMA were resistant to antagonism by 0.1 to 0.3 M NaCl; however, CP26 was resistant to antagonism only by up to 160 mM NaCl. The peptides were generally more antagonized by 3 and 5 mM Mg
2+
and by the polyanion alginate. It appeared that the positively charged C terminus in CP26 altered its ability to permeabilize the cytoplasmic membrane of
Escherichia coli
, although CP26 maintained its ability to kill gram-negative bacteria. These peptides are potential candidates for future therapeutic drugs.
Pharmacokinetics of Dirithromycin in Patients with Mild or Moderate Cirrhosis
Authors: Mazzei Teresita , Surrenti Calogero , Novelli Andrea , Biagini Maria Rosa , Fallani Stefania , Cassetta Maria Iris , Conti Silvia , Surrenti Elisabetta
Published: October 2018

The pharmacokinetics of dirithromycin were determined over a 72-h period following oral administration of a single 500-mg dose to 8 healthy volunteers and to 16 cirrhotic patients (8 patients with class A cirrhosis and 8 patients with class B cirrhosis according to Pugh’s & Child’s classification). Drug levels in plasma and urine were determined by microbiological assay. The mean maximum concentrations of drug in serum obtained 3 to 4 h after administration were 0.29 ± 0.22 mg/liter in volunteers and 0.48 ± 0.21 and 0.52 ± 0.38 mg/liter in patients with class A and class B cirrhosis, respectively. The elimination half-life (
t
1/2β
) was 23.3 ± 7.6 h in healthy subjects and 35.2 ± 11.8 h and 39.5 ± 11.0 h in patients with class A and class B cirrhosis, respectively. The mean area under the concentration-time curve (AUC) and
t
1/2β
were significantly higher in patients with class A and B cirrhosis than in healthy controls, while total and renal clearances were markedly reduced (
P
< 0.01). The time to the maximum concentration of drug in serum and the volume of distribution values appeared to be similar in all groups, and the mean recovery in urine at 72 h ranged from 3.7 to 5.7%, without significant differences among groups. These results demonstrate that some dirithromycin kinetic parameters are significantly different in cirrhotic patients in comparison to those in healthy volunteers. However, an increase in the
t
1/2β
or AUC, which is also observed with other semisynthetic macrolides (e.g., azithromycin), does seem to be not clinically relevant if one takes into account both the high therapeutic indices of these antibiotics and the usually short duration of therapy. Therefore, on the limited basis of single-dose administration, no modifications of dirithromycin dosage seem to be required even for patients with class B liver cirrhosis.
Cloning and Characterization of a Gene,
pbpF
, Encoding a New Penicillin-Binding Protein, PBP2B, in
Staphylococcus aureus
Authors: Komatsuzawa Hitoshi , Choi Gil H. , Ohta Kouji , Sugai Motoyuki , Tran Monique T. , Suginaka Hidekazu
Published: October 2018

A previously unrecognized penicillin binding protein (PBP) gene,
pbpF
, was identified in
Staphylococcus aureus
. This gene encodes a protein of 691 amino acid residues with an estimated molecular mass of 78 kDa. The molecular mass is very close to that of
S. aureus
PBP2 (81 kDa), and the protein is tentatively named PBP2B. PBP2B has three motifs, SSVK, SSN, and KTG, that can be found in PBPs and β-lactamases. Recombinant PBP2B (rPBP2B), which lacks a putative signal peptide at the N terminus and has a histidine tag at the C terminus, was expressed in
Escherichia coli
. The purified rPBP2B was shown to have penicillin binding activity. A protein band was detected from
S. aureus
membrane fraction by immunoblotting with anti-rPBP2B serum. Also, penicillin binding activity of the protein immunoprecipitated with anti-rPBP2B serum was detected. These results suggest the presence of PBP2B in
S. aureus
cell membrane that covalently binds penicillin. The internal region of
pbpF
and PBP2B protein were found in all 12
S. aureus
strains tested by PCR and immunoblotting.
Use of Real-Time PCR and Fluorimetry To Detect Lamivudine Resistance-Associated Mutations in Hepatitis B Virus
Authors: Cane Patricia A. , Cook Pamela , Ratcliffe Daina , Mutimer David , Pillay Deenan
Published: October 2018

Very rapid amplification of DNA by PCR in small volumes can be continuously monitored by the detection of the binding of probes with a rapid cycler with built-in fluorometric detection. Primers were designed to amplify approximately 100 bp of the polymerase gene of hepatitis B virus (HBV) spanning codon 550, where mutations associated with resistance to lamivudine invariably occur. Four hybridization probes were synthesized: one was 3′ labelled with fluorescein and hybridized upstream of codon 550. The others were 5′ labelled with Cy5 and 3′ labelled with biotin and spanned codon 550. The Cy5-labelled oligonucleotides contained either wild-type (ATG) or mutant (GTG or ATT) sequences. A Cy5-labelled probe and either the fluorescein-labelled probe or Sybr Green 1 (a compound that fluoresces when bound to double-stranded DNA) were included in each PCR. After completion of the amplification by using a LightCycler (Idaho Technology), the temperature at which the Cy5 probe melted from the product was determined in a melt program that took ca. 3 min. Pre- and posttreatment samples from eight patients (five chronic and three transplant) who failed lamivudine treatment were amplified, and the presence of mutations in codon 550 was determined by ABI sequencing and by using the LightCycler; in some cases PCR products were also cloned, and multiple clones were sequenced. Concordant results were obtained in all cases. We found the LightCycler to be better at resolving the sequences of genomic mixtures; for example, two samples showed a sequence at codon 550 of (A/G)T(G/T), which was found by fluorimetry to be mixtures of GTG and ATT but no ATG, and this finding was confirmed by the sequencing of clones. However, this approach was not more sensitive than population sequencing for the detection of the presence of mixtures. Overall, this pilot study has demonstrated an approach that could be an extremely rapid and economical method for the detection of lamivudine resistance-associated mutations in HBV.
Efficacy of Locally Delivered Polyclonal Immunoglobulin against
Pseudomonas aeruginosa
Peritonitis in a Murine Model
Authors: Barekzi Nazir A. , Poelstra Kornelis A. , Felts Adrian G. , Rojas Ignacio A. , Slunt Jeffrey B. , Grainger David W.
Published: October 2018

Infectious peritonitis results from bacterial contamination of the abdominal cavity. Conventional antibiotic treatment is complicated both by the emergence of antibiotic-resistant bacteria and by increased patient populations intrinsically at risk for nosocomial infections. To complement antibiotic therapies, the efficacy of direct, locally applied pooled human immunoglobulin G (IgG) was assessed in a murine model (strains CF-1, CD-1, and CFW) of peritonitis caused by intraperitoneal inoculations of 10
6
or 10
7
CFU of
Pseudomonas aeruginosa
(strains IFO-3455, M-2, and MSRI-7072). Various doses of IgG (0.005 to 10 mg/mouse) administered intraperitoneally simultaneously with local bacterial challenge significantly increased survival in a dose-dependent manner. Local intraperitoneal application of 10 mg of IgG increased animal survival independent of either the
P. aeruginosa
or the murine strains used. A local dose of 10 mg of IgG administered up to 6 h prophylactically or at the time of bacterial challenge resulted in 100% survival. Therapeutic 10-mg IgG treatment given up to 12 h postinfection also significantly increased survival. Human IgG administered to the mouse peritoneal cavity was rapidly detected systemically in serum. Additionally, administered IgG in peritoneal lavage fluid samples actively opsonized and decreased the bacterial burden via phagocytosis at 2 and 4 h post-bacterial challenge. Tissue microbial quantification studies showed that 1.0 mg of locally applied IgG significantly reduced the bacterial burden in the liver, peritoneal cavity, and blood and correlated with reduced levels of interleukin-6 in serum.
Effective Treatment of Acute and Chronic Murine Tuberculosis with Liposome-Encapsulated Clofazimine
Authors: Adams Linda B. , Sinha Indu , Franzblau Scott G. , Krahenbuhl James L. , Mehta Reeta T.
Published: October 2018

The therapeutic efficacy of liposomal clofazimine (L-CLF) was studied in mice infected with
Mycobacterium tuberculosis
Erdman. Groups of mice were treated with either free clofazimine (F-CLF), L-CLF, or empty liposomes twice a week for five treatments beginning on day 1 (acute), day 21 (established), or day 90 (chronic) postinfection. One day after the last treatment, the numbers of CFU of
M. tuberculosis
in the spleen, liver, and lungs were determined. F-CLF at the maximum tolerated dose of 5 mg/kg of body weight was ineffective; however, 10-fold-higher doses of L-CLF demonstrated a dose response with significant CFU reduction in all tissues without any toxic effects. In acutely infected mice, 50 mg of L-CLF/kg reduced CFU 2 to 3 log units in all three organs. In established or chronic infection, treated mice showed no detectable CFU in the spleen or liver and 1- to 2-log-unit reduction in the lungs. A second series of L-CLF treatments cleared
M. tuberculosis
in all three tissues. L-CLF appears to be bactericidal in the liver and spleen, which remained negative for
M. tuberculosis
growth for 2 months. Thus, L-CLF could be useful in the treatment of tuberculosis.
Comparative Efficacies of Antibiotics in a Rat Model of Meningoencephalitis Due to
Listeria monocytogenes
Authors: Michelet Christian , Leib Stephen L. , Bentue-Ferrer Daniele , Täuber Martin G.
Published: October 2018

The antibacterial activities of amoxicillin-gentamicin, trovafloxacin, trimethoprim-sulfamethoxazole (TMP-SMX) and the combination of trovafloxacin with TMP-SMX were compared in a model of meningoencephalitis due to
Listeria monocytogenes
in infant rats. At 22 h after intracisternal infection, the cerebrospinal fluid was cultured to document meningitis, and the treatment was started. Treatment was instituted for 48 h, and efficacy was evaluated 24 h after administration of the last dose. All tested treatment regimens exhibited significant activities in brain, liver, and blood compared to infected rats receiving saline (
P
< 0.001). In the brain, amoxicillin plus gentamicin was more active than all of the other regimens, and trovafloxacin was more active than TMP-SMX (bacterial titers of 4.1 ± 0.5 log
10
CFU/ml for amoxicillin-gentamicin, 5.0 ± 0.4 log
10
CFU/ml for trovafloxacin, and 5.8 ± 0.5 log
10
CFU/ml for TMP-SMX;
P
< 0.05). In liver, amoxicillin-gentamicin and trovafloxacin were similarly active (2.8 ± 0.8 and 2.7 ± 0.8 log
10
CFU/ml, respectively) but more active than TMP-SMX (4.4 ± 0.6 log
10
CFU/ml;
P
< 0.05). The combination of trovafloxacin with TMP-SMX did not alter the antibacterial effect in the brain, but it did reduce the effect of trovafloxacin in the liver. Amoxicillin-gentamicin was the most active therapy in this study, but the activity of trovafloxacin suggests that further studies with this drug for the treatment of
Listeria
infections may be warranted.
Sequence Diversity of the Reverse Transcriptase of Human Immunodeficiency Virus Type 1 from Untreated Brazilian Individuals
Authors: Brindeiro Rodrigo , Vanderborght Bart , Caride Elena , Correa Letícia , Oravec Rejane M. , Berro Oscar , Stuyver Lieven , Tanuri Amilcar
Published: October 2018

The presence of human immunodeficiency virus type 1 (HIV-1) bearing mutations resistant to nucleosidic inhibitors of the viral reverse transcriptase (RT) derived from HIV-seropositive asymptomatic and untreated volunteer blood donors was examined. The RT amplicons of 32 specimens were analyzed by using a reverse hybridization line probe assay technique that detects resistance against zidovudine (3′-azido-3′-deoxythymidine [AZT], didanosine (2′,3′-dideoxyinosine [ddI], zalcitabine (2′,3′-dideoxycytidine [ddC]), and lamivudine {(−)-β-
l
-2′,3′-dideoxy-3′-thiacytidine [3TC]} at amino acid positions 41, 69, 70, 74, 184, and 215 of the HIV RT. One sample (brp004, subtype B) showed an AZT resistance secondary mutation at position K70R. Fifteen specimens revealed one or more sites of nonreactivity to both wild-type- and mutant-specific probes (dual nonreactivity). Samples were also submitted to RT direct sequencing and phylogenetic analysis. Nine of 32 specimens belonged to non-B subtypes (C, D, F, and F/B or B/F mosaics). Three of these non-B isolates, named brp004, brp063, and brp069, revealed three other relevant AZT resistance mutations—a T215F mutation and two M41L mutations, respectively—hidden by the nonreactivity to line probe assay strips on the respective codon regions. The isolate brp004 also carried a D67N AZT resistance mutation revealed by direct sequencing. No nonnucleosidic RT inhibitor-resistant mutation was found. The analysis revealed a frequency of 2.26 × 10
−4
mutations per nucleotide for independent samples related to RT resistance. These findings emphasize the magnitude of naturally occurring reservoirs of drug-resistant virus among untreated HIV-1-positive individuals in Brazil.