Comparative In Vitro Surveillance of Amoxicillin-Clavulanic Acid and Four Oral Comparators Against 21,232 Clinical Isolates from Europe

2003 ◽  
Vol 22 (4) ◽  
pp. 261-267 ◽  
Author(s):  
D. J. Hoban ◽  
S. K. Bouchillon ◽  
J. L. Johnson ◽  
G. G. Zhanel ◽  
D. L. Butler ◽  
...  
Author(s):  
Leonardo Mancabelli ◽  
Walter Mancino ◽  
Gabriele Andrea Lugli ◽  
Chiara Argentini ◽  
Giulia Longhi ◽  
...  

Amoxicillin-Clavulanic acid (AMC) is one of the most frequently prescribed antibiotic formulations in the Western world. Extensive oral use of this antimicrobial combination influences the gut microbiota. One of the most abundant early colonizers of the human gut microbiota is represented by different taxa of the Bifidobacterium genus, which include many members that are considered to bestow beneficial effects upon their host. In the current study, we investigated the impact of AMC administration on the gut microbiota composition, comparing the gut microbiota of 23 children that had undergone AMC antibiotic therapy to that of 19 children that had not been treated with antibiotics during the preceding six months. Moreover, we evaluated AMC sensitivity by Minimal Inhibitory Concentration (MIC) test of 261 bifidobacterial strains, including reference strains for the currently recognized 64 bifidobacterial (sub)species, as well as 197 bifidobacterial isolates of human origin. These assessments allowed the identification of four bifidobacterial strains, which exhibit a high level of AMC insensitivity, and which were subjected to genomic and transcriptomic analyses to identify the putative genetic determinants responsible for this AMC insensitivity. Furthermore, we investigated the ecological role of AMC-resistant bifidobacterial strains by in vitro batch-cultures. Importance Based on our results, we observed a drastic reduction in gut microbiota diversity of children treated with antibiotics, also affecting the abundance of Bifidobacterium, a bacterial genus commonly found in the infant gut. MIC experiments revealed that more than 98% of bifidobacterial strains tested were shown to be inhibited by the AMC antibiotic. Isolation of four insensitive strains and sequencing of their genome revealed the identity of possible genes involved in AMC resistance mechanisms. Moreover, gut-simulating in-vitro experiments revealed that one strain, i.e. B. breve PRL2020, is able to persist in the presence of a complex microbiota combined with AMC antibiotic.


1995 ◽  
Vol 12 (4) ◽  
pp. 157-160 ◽  
Author(s):  
C.E. Harvey ◽  
C. Thornsberry ◽  
B.R. Miller ◽  
F. S. Shofer

The aerobic and anaerobic flora from gingival pockets of 40 cats with established gingivitis were cultured. The susceptibility of each isolate to four antimicrobial agents currently approved for use in cats (amoxicillin-clavulanic acid; clindamycin; cefadroxil; enrofloxacin) was determined. Amoxicillin-clavulanic acid (Clavamox®) had the highest in-vitro susceptibility against all isolates (92%) and all anaerobes (99% [co-equal with clindamycin]) tested; enrofloxacin (Baytril®) had the highest in-vitro susceptibility against all aerobes (90%) tested.


Author(s):  
Ángel Rodríguez-Villodres ◽  
María Luisa Gil-Marqués ◽  
Rocío Álvarez-Marín ◽  
Rémy A Bonnin ◽  
María Eugenia Pachón-Ibáñez ◽  
...  

Abstract Objectives Escherichia coli is characterized by three resistance patterns to β-lactams/β-lactamase inhibitors (BLs/BLIs): (i) resistance to ampicillin/sulbactam and susceptibility to amoxicillin/clavulanic acid and piperacillin/tazobactam (RSS); (ii) resistance to ampicillin/sulbactam and amoxicillin/clavulanic acid, and susceptibility to piperacillin/tazobactam (RRS); and (iii) resistance to ampicillin/sulbactam, amoxicillin/clavulanic acid and piperacillin/tazobactam (RRR). These resistance patterns are acquired consecutively, indicating a potential risk of developing resistance to piperacillin/tazobactam, but the precise mechanism of this process is not completely understood. Methods Clinical isolates incrementally pressured by piperacillin/tazobactam selection in vitro and in vivo were used. We determined the MIC of piperacillin/tazobactam in the presence and absence of piperacillin/tazobactam pressure. We deciphered the role of the blaTEM genes in the new concept of extended-spectrum resistance to BLs/BLIs (ESRI) using genomic analysis. The activity of β-lactamase was quantified in these isolates. Results We show that piperacillin/tazobactam resistance is induced in E. coli carrying blaTEM genes. This resistance is due to the increase in copy numbers and transcription levels of the blaTEM gene, thus increasing β-lactamase activity and consequently increasing piperacillin/tazobactam MICs. Genome sequencing of two blaTEM-carrying representative isolates showed that piperacillin/tazobactam treatment produced two types of duplications of blaTEM (8 and 60 copies, respectively). In the clinical setting, piperacillin/tazobactam treatment of patients infected by E. coli carrying blaTEM is associated with a risk of therapeutic failure. Conclusions This study describes for the first time the ESRI in E. coli. This new concept is very important in the understanding of the mechanism involved in the acquisition of resistance to BLs/BLIs.


2015 ◽  
Vol 19 (6) ◽  
pp. 592-594 ◽  
Author(s):  
Ekaterini Syrigou ◽  
Dimitra Grapsa ◽  
Andriani Charpidou ◽  
Konstantinos Syrigos

Drug-induced acute generalized exanthematous pustulosis is a rare pustular skin reaction, most commonly triggered by antibiotics. Although its diagnosis is based primarily on the presence of specific clinical and histopathologic features, additional in vivo (patch testing) or in vitro testing may be required, especially in atypical cases, to more accurately determine the causative agent. The authors report a histologically confirmed case of acute generalized exanthematous pustulosis that was induced by amoxicillin/clavulanic acid, as documented by subsequent patch testing, and presented with generalized painful lymphadenopathy, mimicking an acute infectious process. This is a very rare and diagnostically challenging clinical presentation of acute generalized exanthematous pustulosis, which has been reported, to the best of our knowledge, only once previously.


2014 ◽  
Vol 17 (3) ◽  
pp. 83 ◽  
Author(s):  
Marcos Sergio Endo ◽  
Fernanda Graziela Corrêa Signoretti ◽  
Vivian Sayuri Kitayama ◽  
Ariane Cássia Salustiano Marinho ◽  
Frederico Canato Martinho ◽  
...  

<p><strong>Objective: </strong>The aim of this study was to evaluate the minimal inhibitory concentrations (MIC) of different antibiotic agents against to the most prevalent microorganism found in root-filled canals by culture and molecular approaches. <strong>Material and </strong><strong>Methods: </strong>The microbial samples were taken either from thirty root-filled canals after removal of gutta-percha. Culture methods and 16s rDNA assay were used to identify the <em>E faecails</em> present in the samples. The antimicrobial susceptibilities of the isolates of <em>E faecalis </em>were determined by MIC values using the E test System and interpreted according to the Clinical and Laboratory Standards Institute guidelines. The following antibiotics were used: benzylpenicillin, amoxicillin, amoxicillin-clavulanic acid, erythromycin, azithromycin, vancomycin, chloramphenicol, tetracycline, doxycycline, ciprofloxacin, rifampicin and moxifloxacin. <strong>Results: </strong><em>E faecalis</em> were isolated (7/30) and detected (13/30) by culture and PCR assay, respectively. All tested <em>E faecalis</em> (<em>n</em>=12) were highly sensitive to amoxicillin, moxifloxacin, vancomycin, benzylpenicillin and amoxicillin-clavulanic acid. Some antibiotics were resistant against <em>E faecalis </em>strains such as rifampicin (4/12), tetracycline (2/12), doxycycline (1/12), erythromycin (3/12) and azythromycin (8/12). <strong>Conclusion</strong>: Amoxicillin, amoxicillin-clavulanic acid, benzylpenicillin, vancomycin and moxifloxacin were the most active antibiotics, in vitro, against <em>E faecalis</em> clinical strains, with all the isolates being susceptible. Azithromycin and erythromycin were least effective, with none percentage of isolates being susceptible, during laboratory testing. Moreover, <em>E faecalis </em>were identified more frequently by PCR assay than by culture technique.</p><p><strong>Keywords: </strong>Retreatment; Antibiotics, antimicrobial susceptibility; <em>Enterococcus faecalis;</em> Antibiotic resistance. </p>


1999 ◽  
Vol 43 (5) ◽  
pp. 1270-1273 ◽  
Author(s):  
E. Könönen ◽  
A. Kanervo ◽  
K. Salminen ◽  
H. Jousimies-Somer

ABSTRACT Oral Fusobacterium nucleatum populations from 20 young, healthy children were examined for β-lactamase production. Ten children (50%) harbored, altogether, 25 β-lactamase-positiveF. nucleatum isolates that were identified as F. nucleatum subsp. polymorphum, F. nucleatum subsp. nucleatum, and F. nucleatum subsp. vincentii (J. L. Dzink, M. T. Sheenan, and S. S. Socransky, Int. J. Syst. Bacteriol. 40:74–78, 1990). In vitro susceptibility of these β-lactamase-producing and 26 non-β-lactamase-producing F. nucleatum isolates was tested with penicillin G, amoxicillin-clavulanic acid, tetracycline hydrochloride, metronidazole, trovafloxacin, and azithromycin. Except for penicillin G, the antimicrobials exhibited good activity against all F. nucleatum isolates.


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