scholarly journals In Vitro Activity of Difloxacin against Canine Bacterial Isolates

2000 ◽  
Vol 12 (3) ◽  
pp. 218-223 ◽  
Author(s):  
R. van den Hoven ◽  
J. A. Wagenaar ◽  
R. D. Walker
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Proteus Mirabilis ◽  
In Vitro Activity ◽  
Bacterial Isolates ◽  
Postantibiotic Effect ◽  
Gram Negative ◽  
Neutral Ph ◽  
Staphylococcus Intermedius

The in vitro activity of difloxacin against canine bacterial isolates from clinical cases was studied in the United States and The Netherlands. Minimal inhibitory concentrations (MIC), the postantibiotic effect, the effect of pH on antimicrobial activity, and the bacterial killing rate tests were determined according to standard techniques. The MICs of American and Dutch isolates agreed in general. The MICs of the American gram-negative isolates ranged from 0.06 to 2.0 μg/ml, and the MICs of the Dutch gram-negative isolates ranged from 0.016 to 8.0 μg/ml. A few European strains of Proteus mirabilis and Klebsiella pneumoniae had relatively high MICs. Bordetella bronchiseptica also was less susceptible to difloxacin. The MICs of the American gram-positive cocci ranged from 0.125 to 4.0 μg/ml, and the MICs of Dutch isolates ranged from 0.125 to 2.0 μg/ml. Difloxacin induced a concentration-dependent postantibiotic effect that lasted 0.2–3 hours in cultures with Escherichia coli, Staphylococcus intermedius, Streptococcus canis, Proteus spp., and Klebsiella pneumoniae. There was no postantibiotic effect observed against canine Pseudomonas aeruginosa. Decreasing the pH of the medium increased the MIC of Proteus mirabilis for difloxacin. The MICs of Escherichia coli and Klebsiella pneumoniae were lowest at neutral pH and were slightly increased in acid or alkaline media. At a neutral pH, most tested bacterial species were killed at a difloxacin concentration of 4 times the MIC. Similar results were obtained when these same bacteria were tested against enrofloxacin. A Klebsiella pneumoniae strain in an acidic environment was readily killed at difloxacin or enrofloxacin MIC, but at neutral pH the drug concentration had to be raised to 4 times the MIC for a bactericidal effect. After 24 hours of incubation at pH 7.1, difloxacin and enrofloxacin had similar bactericidal activity for all bacteria tested except Staphylococcus intermedius. Against S. intermedius, difloxacin was more bactericidal than enrofloxacin.

scholarly journals In Vitro Activity of Cefotetan against ESBL-Producing Escherichia coli and Klebsiella pneumoniae Bloodstream Isolates from the MERINO Trial

2021 ◽  
Author(s):  
Adam G. Stewart ◽  
Kyra Cottrell ◽  
Andrew Henderson ◽  
Kanthi Vemuri ◽  
Michelle J. Bauer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Severe Infection ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Gram Negative ◽  
Carbapenem Resistant

Carbapenem antibiotics remain the treatment of choice for severe infection due to ESBL- and AmpC-producing Enterobacterales . The use of carbapenems is a major driver of the emergence of carbapenem-resistant Gram-negative bacilli, which are often resistant to most available antimicrobials.

scholarly journals Postantibiotic Effect of Tigecycline against 14 Gram-Positive Organisms

2008 ◽  
Vol 53 (2) ◽  
pp. 782-784 ◽  
Author(s):  
G. A. Pankuch ◽  
P. C. Appelbaum
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Haemophilus Influenzae ◽  
Acinetobacter Baumannii ◽  
Enterobacter Cloacae ◽  
Postantibiotic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Negative Organisms

ABSTRACT The in vitro postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects of tigecycline were determined for 14 gram-positive and gram-negative organisms. The pneumococcal, staphylococcal, and enterococcal PAEs were 1.9 to 5.1, 2.9 to 5.7, and 3.9 to 6.1 h, respectively, and those for Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Acinetobacter baumannii were 1.1 to 5.0, 1.9 to 2.1, 1.7 to 1.8, 1.0 to 1.7, and 0.7 to 3 h, respectively. The PA-SMEs (four times the MIC) ranged from 6.7 to >11 h for gram-positive organisms and from 2.3 to >11.3 h for gram-negative organisms.

scholarly journals Comparison of the Superpolymyxin and ChromID Colistin R Screening Media for the Detection of Colistin-Resistant Enterobacteriaceae from Spiked Rectal Swabs

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Delphine Girlich ◽  
Thierry Naas ◽  
Laurent Dortet
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Confidence Interval ◽  
Enterobacter Cloacae ◽  
Bacterial Isolates ◽  
Colistin Resistance ◽  
Gram Negative ◽  
Content Type ◽  
Rectal Swabs ◽  
Stool Samples

ABSTRACT The dissemination of carbapenemase-producing Enterobacteriaceae (CPE) has led to the increased use of colistin, which has resulted in the emergence of colistin-resistant Enterobacteriaceae worldwide. One of the most threatening scenarios is the dissemination of colistin resistance in CPE, particularly the plasmid-encoded resistance element MCR. Thus, it has now become mandatory to possess reliable media to screen for colistin-resistant Gram-negative bacterial isolates, especially Enterobacteriaceae. In this study, we evaluated the performances of the Superpolymyxin medium (ELITechGroup) and the ChromID Colistin R medium (bioMérieux) to screen for colistin-resistant Enterobacteriaceae from spiked rectal swabs. Stool samples were spiked with a total of 94 enterobacterial isolates (Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Enterobacter cloacae), including 53 colistin-resistant isolates. ESwabs (Copan Diagnostics) were then inoculated with those spiked fecal suspensions, and culture proceeded as recommended by both manufacturers. The sensitivity of detection of colistin-resistant Enterobacteriaceae was 86.8% (95% confidence interval [95% CI] = 74.0% to 94.0%) using both the Superpolymyxin medium and the ChromID Colistin R plates. Surprisingly, the isolates that were not detected were not the same for both media. The specificities were high for both media, at 97.9% (95% CI = 87.3% to 99.9%) for the Superpolymyxin medium and 100% (95% CI = 90.4% to 100%) for the ChromID Colistin R medium. Both commercially available media, ChromID Colistin R and Superpolymyxin, provide useful tools to screen for colistin-resistant Enterobacteriaceae from patient samples (rectal swabs) regardless of the level and mechanism of colistin resistance.

scholarly journals Efeito antimicrobiano do extrato de Cranberry sobre micro-organismos causadores de infecção urinária

2016 ◽  
Vol 11 (31) ◽  
pp. 113-122
Author(s):  
Carla Franco Porto Belmont Souza ◽  
Luiz Eduardo Souza da Silva Irineu ◽  
Renan Silva De Souza ◽  
Renato da Silva Teixeira ◽  
Ivina Sanches Pereira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Enterococcus Faecalis ◽  
Proteus Mirabilis ◽  
Enterococcus Faecium ◽  
Vaccinium Macrocarpon ◽  
Mueller Hinton

A resistência microbiana tem se mostrado um problema de proporções mundiais, causando estado de morbidade e mortalidade em diversos pacientes. Em vista disso, tem crescido a busca por métodos alternativos naturais de profilaxia. A investigação clínica sugere que o Extrato de Cranberry está entre as melhores propostas de prevenção natural. O Cranberry (Vaccinium macrocarpon) é um fruto que tem crescido comercialmente pelo sabor e propriedades benéficas à saúde. Dentre as formas comercializadas estão: o suco, o chá e as cápsulas contendo o extrato seco. A ação desta planta está relacionada ao tratamento de doenças do trato urinário, por possuir substâncias que inibem a adesão bacteriana ao epitélio do trato urinário, dificultando sua proliferação e reprodução. Dentre todas as infecções relacionadas à assistência a saúde, a Infecção do Trato Urinário é a mais frequentemente associada a procedimentos invasivos. Se não for tratada, pode resultar em complicações como pielonefrite aguda, bacteremia e pionefrose. Portanto, cranberry pode ser uma nova alternativa para o combate das infecções uroepiteliais, por ser um produto natural de preço acessível, e com formas de comercialização diversificada, ao contrário dos antimicrobianos convencionais, que por sua vez são caros e podem acabar causando resistência nos micro-organismos. Este trabalho teve como objetivo avaliar in vitro a atividade antimicrobiana do extrato de Cranberry, adquirido em farmácia de manipulação, sobre 8 micro-organismos isolados de infecções urinárias. As cepas utilizadas, adquiridas da coleção da FIOCRUZ, foram: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Serratia marscecens, Staphylococcus aureus, Enterococcus faecalis e Enterococcus faecium. No estudo, foram utilizados o caldo Mueller Hinton (MH), Extrato de Cranberry e as bactérias patogênicas. O ensaio foi realizado em triplicata, com o uso de um controle de crescimento dos micro-organismos e o experimento para avaliação do crescimento bacteriano na presença do extrato. A turbidez foi medida com o auxílio de um espectrofotômetro, no comprimento de onda de 600 nm, antes e após 24 horas de incubação à 37 ºC. O procedimento forneceu a Densidade Ótica, do qual possibilitou a identificação da inibição microbiana. Para análise estatística foi utilizado o Teste t de Student. O Extrato de Cranberry apresentou atividade antimicrobiana sobre as bactérias Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Serratia marscecens e Enterococcus faecalis (p < 0,05), confirmando seu efeito benéfico em infecções urinárias. No entanto, não teve efeito inibitório significativo sobre Pseudomonas aeruginosa, Proteus mirabilis e Enterococcus faecium (p > 0,05).

scholarly journals In Vitro Activity of a Novel Siderophore-Cephalosporin, GT-1 and Serine-Type β-Lactamase Inhibitor, GT-055, against Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. Panel Strains

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 267 ◽  
Author(s):  
Le Phuong Nguyen ◽  
Naina Adren Pinto ◽  
Thao Nguyen Vu ◽  
Hyunsook Lee ◽  
Young Lag Cho ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Vitro Activity ◽  
Intrinsic Activity ◽  
In Vitro Activity ◽  
E Coli ◽  
Acinetobacter Spp ◽  
Resistant Strains ◽  
Lactamase Inhibitor

This study investigates GT-1 (also known as LCB10-0200), a novel-siderophore cephalosporin, inhibited multidrug-resistant (MDR) Gram-negative pathogen, via a Trojan horse strategy exploiting iron-uptake systems. We investigated GT-1 activity and the role of siderophore uptake systems, and the combination of GT-1 and a non-β-lactam β-lactamase inhibitor (BLI) of diazabicyclooctane, GT-055, (also referred to as LCB18-055) against molecularly characterised resistant Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. isolates. GT-1 and GT-1/GT-055 were tested in vitro against comparators among three different characterised panel strain sets. Bacterial resistome and siderophore uptake systems were characterised to elucidate the genetic basis for GT-1 minimum inhibitory concentrations (MICs). GT-1 exhibited in vitro activity (≤2 μg/mL MICs) against many MDR isolates, including extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing E. coli and K. pneumoniae and oxacillinase (OXA)-producing Acinetobacter spp. GT-1 also inhibited strains with mutated siderophore transporters and porins. Although BLI GT-055 exhibited intrinsic activity (MIC 2–8 μg/mL) against most E. coli and K. pneumoniae isolates, GT-055 enhanced the activity of GT-1 against many GT-1–resistant strains. Compared with CAZ-AVI, GT-1/GT-055 exhibited lower MICs against E. coli and K. pneumoniae isolates. GT-1 demonstrated potent in vitro activity against clinical panel strains of E. coli, K. pneumoniae and Acinetobacter spp. GT-055 enhanced the in vitro activity of GT-1 against many GT-1–resistant strains.

scholarly journals 598. In Vitro Activity of Aztreonam in Combination with Ceftazidime–Avibactam, Amoxicillin–Clavulanate, and Piperacillin–Tazobactam vs. NDM-Producing Escherichia coli and Klebsiella pneumoniae Clinical Isolates

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S281-S281
Author(s):  
Andrew Walkty ◽  
James Karlowsky
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
In Vitro Activity ◽  
Zone Diameter ◽  
Amoxicillin Clavulanate ◽  
Lactamase Inhibitor

Abstract Background There are limited options available for the treatment of infections caused by Enterobacteriaceae that produce an NDM metallo-β-lactamase. The purpose of this study was to compare the in vitro activity of aztreonam in combination with three different β-lactam/β-lactamase inhibitors (ceftazidime–avibactam, amoxicillin-clavulanate, piperacillin–tazobactam) vs. NDM-positive Enterobacteriaceae clinical isolates. Methods Seven Escherichia coli and three Klebsiella pneumoniae clinical isolates (all NDM-positive by PCR) were included in this study. The in vitro activities of ceftazidime–avibactam, amoxicillin-clavulanate, piperacillin–tazobactam, and aztreonam were determined by disk diffusion as described by CLSI. For synergy testing, disks containing a β-lactamase inhibitor (ceftazidime–avibactam, amoxicillin-clavulanate, piperacillin tazobactam) were applied to Mueller–Hinton agar plates inoculated with the test organisms, and the plates were incubated for 1 hour. The disks were then removed and aztreonam disks were dropped on the previous disk sites. The plates were then incubated as per standard CLSI recommendations for disk diffusion testing. Results All ten isolates demonstrated phenotypic resistance to aztreonam, amoxicillin-clavulanate, and piperacillin–tazobactam, and eight were resistant to ceftazidime–avibactam (CLSI breakpoints). The zone diameter observed for aztreonam in combination with ceftazidime–avibactam was greater than for either antimicrobial on its own for nine isolates. Seven isolates (70%) had susceptibility to aztreonam restored (zone diameter ≥21 mm) in the presence of avibactam. Aztreonam in combination with amoxicillin-clavulanate demonstrated in increase in zone diameter for all isolates relative to the zone for each antimicrobial alone, but only two (20%) had aztreonam susceptibility restored. Aztreonam susceptibility was not restored for any of the isolates in combination with piperacillin–tazobactam. Conclusion Of the three β-lactam/β-lactamase inhibitor-aztreonam combinations evaluated, ceftazidime–avibactam plus aztreonam demonstrated the greatest in vitro activity vs. NDM-producing Enterobacteriaceae. Disclosures All authors: No reported disclosures.

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