Activity of sub-minimal inhibitory concentrations of aspoxicillin in prolonging the postantibiotic effect against <i>Staphylococcus aureus</i>

Oshida, Tadahiro; Onta, Tokio; Nakanishi, Noriyuki; Matsushita, Tadahiro; Yamaguchi, Toutaro

doi:10.1093/jac/26.1.29

Cited by 25 publications

(11 citation statements)

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“…This phe nomenon has already been described in this study and has also been studied in vivo [6,29]. Oshida et al [30] observed a reduction in the PAE of aspoxicillin and piperacillin against S. aureus when they injected (3-lacta mase at the beginning of the PAE phase to remove the sub-MICs.…”

Section: Discussionsupporting

confidence: 64%

Pharmacodynamic Effects of Ciprofloxacin, Fleroxacin and Lomefloxacin in vivo and in vitro

Fuentes

Martín²,

Izquierdo³

et al. 1996

Chemotherapy

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The present study investigates the postantibiotic effect (PAE) in vivo, and the postantibiotic subinhibitory concentration effects (PA-SE) in vitro and SE in vivo of three 4-fluoroquinolones (ciprofloxacin, fleroxacin and lomefioxacin) against standard strains of Staphylococcus aureus and Escherichia coli. In vivo killing kinetics have also been performed using two different short administrations to study if the PAE duration could cover the time that the antibiotic was below the minimal inhibitory concentration (MIC) in serum. The results show that the three antimicrobial agents induced long PAEs (1.9–3.1 h) against the two microorganisms. Moderate but significant in vitro PA-SEs were also produced (1– > 9 h). The in vivo SEs were not significant except when the effect of lomefioxacin on E. coli was assayed (0.54 h). Finally, the in vivo killing kinetics showed that the administrations that included the PAE duration were as effective as the schedule that maintained the antibiotic levels in serum above the MIC. Only when fleroxacin and S. aureus were assayed, this last administration was more effective (+ 0.9 log₁₀ colony-forming units/thigh).

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Section: Discussionsupporting

confidence: 64%

Pharmacodynamic Effects of Ciprofloxacin, Fleroxacin and Lomefloxacin in vivo and in vitro

Fuentes

Martín²,

Izquierdo³

et al. 1996

Chemotherapy

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“…In an earlier study (27), we demonstrated that when P-hemolytic streptococci in the PA phase were again exposed to 0.2 and 0.3 x MIC after washing, no regrowth was observed for more than 24 h. In contrast, bacteria which had only been exposed to sub-MICs showed growth curves that were almost identical to those of the controls (27). Later, Oshida et al, using the same experimental design, showed that staphylococci in the PA phase were also more susceptible to sub-MICs of ,-lactam antibiotics compared with the controls (30). In the present study we have extended our earlier findings and could demonstrate that also in other antibiotic-bacterial combinations, the effects of sub-MICs on bacteria in the PA phase (PA SME) are much more pronounced than the direct effect of sub-MICs (SME) and than the PAE (Table 1).…”

Section: Discussionmentioning

confidence: 98%

Pharmacodynamic effects of subinhibitory concentrations of beta-lactam antibiotics in vitro

Odenholt-Tornqvist

Löwdin

Cars

1991

Antimicrob Agents Chemother

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The pharmacodynamic effects of subinhibitory concentrations of different ,B-lactam antibiotics were investigated. A postantibiotic effect (PAE) was induced for different bacterial species by exRosure to lOx MIC of several ,B-lactam antibiotics for 2 h in vitro. The antibiotic-bacterial combinations used in this study were imipenemPseudomonas aeruginosa, benzylpenicillin-Streptococcus pneumonae and -Streptococcus pyogenes, cgefcanel-S. pyogenes, ampicillin-Escherichia coli, and piperacillin-E. coli. After the induction of the PAE, the exposed cultures as well as the unexposed controls were washed and diluted. Thereafter, the cultures in the postantibiotic phase (PA phase) and the cultures not previously treated with antibiotics were exposed to 0.1, 0.2, and 0.3x MIC of the relevant drug and the growth curves were compared. When bacteria in the PA phase were exposed to sub-MICs, a substantial prolongation of the time before regrowth was demonstrated, especially in antibioticbacterial combinations for which a PAE wqs found. In contrast, sub-MICs on cultures not previously exposed to suprainhibitory antibiotic concentrations yielded oidy a slight reduction in growth rate compared with the controls. Thus, it seems important to distinguish the direct effects of sub-MICs on bacteria not previously exposed to suprainhibitory concentrations from the effects of sub-MICs on bacteria in the PA phase.The effects on bacteria of subinhibitory antibiotic concentrations (sub-MICs) were noted early in the antibiotic era. In 1944, Eagle and Musselman reported a temporary inhibition of the growth of spirochetes after exposure to sub-MICs of penicillin in vitro (10). Clinical experience at that time also revealed satisfactory results when patients with pneumococcal pneumonia were treated with low doses of penicillin which could hardly have yielded concentrations in serum above the MIC (38). Furthermore, Eagle and coworkers showed, both in vitro and in a rabbit model, that grampositive bacteria exposed to a suprainhibitory concentration of penicillin did not return to a growth phase immediately after the concentration in serum had fallen under the MIC (9, 11). This effect was later named the postantibiotic effect (PAE) and is one of many explanations for the success of intermittent dosage with antibiotics (7). Another factor of importance for the success of discontinuous antibiotic dosing is the function of a normal host defense system. For example, it does not seem to be necessary to keep the level of P-lactam antibiotics in serum above the MIC to clear an infection in immunocompetent animals, whereas several studies using neutropenic animals have shown the importance of maintaining levels of P-lactam antibiotics in serum above the MIC in order to avoid regrowth of gram-negative bacteria (3,14,33). One reason for the difference between immunocompetent and neutropenic animals is that bacteri,a exposed to sub-MICs in immunocompetent animals are more susceptible to phagocytic cell functions (13,19,24,26,41). Sub-MICs can also exert a d...

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“…PAE refers to the suppression of bacterial growth that persists following limited exposure of bacteria to antimicrobial agents and subsequent removal of the antibiotic either by dilution, drug inactivation or repeated washing (Bundtzen et af, 198 1 ;Gerber and Craig, 198 1 ;Vogelman and Craig, 1985). PAE has been demonstrated with Gram-positive (Gerber and Craig, 1981;Oshida et al, 1990), as well as Gram-negative bacteria (Gerber et al, 1982;Isaksson et al, 1988;Pruul and McDonald, 1990). It has to be emphasized that the PAE is due to prior exposure of the organism to antibiotics for a short duration rather than a continuous exposure for a longer period of time as in the estimates of minimum inhibitory concentrations (McDonald et af, 1977;Vogelman and Craig, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…Although a number of workers have studied the PAE of antibacterial agents against many bacterial isolates (Gerber and Craig, 1981;Gerber et al, 1982;Vogelman and Craig, 1985;Isaksson et al, 1988;Oshida et al, 1990;Pruul and McDonald, 1990;Craig and Gudmundsson, 1996), there is a sparsity of data on the postantifungal effect (PAFE) of antifungals on Cundida species (Craig and Gudmundsson, 1996). and no such information on oral C. albicans isolates.…”

Section: Introductionmentioning

confidence: 99%

The postantifungal effect (PAFE) of antimycotics on oral C. albicans isolates and its impact on candidal adhesion

Ellepola

Samaranayake

1998

Oral Diseases

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OBJECTIVE: Postantifungal effect (PAFE) is defined as the suppression of growth that persists following limited exposure of yeasts to antimycotics and subsequent removal of the drug. As there are no data on the PAFE of oral C albicans isolates the main aim of this investigation was to measure the PAFE of 10 oral isolates of C albicans following limited exposure (I h) to five antifungal drugs, including nystatin which has not been previously used in PAFE assays. A secondary aim of the study was to evaluate the biological significance of PAFE, using a nystatin pre‐exposed isolate of C albicans and observing its adherence to denture acrylic surfaces, during the PAFE period. DESIGN: A total of 10 oral isolates of C albicans were examined for the presence of the PAFE after I h exposure to five antifungal drugs, nystatin, amphotericin B, 5‐fluorocytosine, ketoconazole and fluconazole. PAFE was automatically assessed with the help of a Spectramax machine which utilizes the principle of periodic turbidometric assessment of growth rates at a given temperature over a given period. The data thus collected are automatically processed in a graphic format as a computer printout. The PAFE was determined as the difference in time (h) required for growth of the drug‐free control and the drug‐exposed test cultures to increase to 0.05 absorbance level following removal of the antifungal agent (by repeated washing). The adhesion of the single isolate to denture acrylic following limited exposure to nystatin was assessed by a previously described in vitro adhesion assay. RESULTS: Significant PAFE were observed for nystatin, amphotericin‐B and 5‐fluorocytosine. A marginal PAFE was observed for ketoconazole and little or none for fluconazole. The mean duration of the PAFE of nystatin, amphotericin‐B, 5‐fluorocytosine, ketoconazole and fluconazole were 2.89 (±0.27) h, 2.83 (±0.23) h, 3.18 (±0.31) h, 0.65 (±0.11) h and 0.16 (±0.06) h, respectively. The mean percentage reduction of adhesion of oral C albicans BU47204 to denture acrylic during the PAFE period following exposure to nystatin for 10, 30, 50, 70 and 90 min was 9.12%, 61.73%, 65.99%, 82.16% and 83.14%, respectively. CONCLUSIONS: These in vitro findings imply that even a short period of exposure to antifungals may result in modulation of the growth and the virulent attributes of C albicans, which however is largely dictated by the anti‐mycotic agent in question. Whether such mechanisms operate in vivo needs to be clarified by further studies.

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Activity of sub-minimal inhibitory concentrations of aspoxicillin in prolonging the postantibiotic effect against Staphylococcus aureus

Cited by 25 publications

References 0 publications

Pharmacodynamic Effects of Ciprofloxacin, Fleroxacin and Lomefloxacin in vivo and in vitro

Pharmacodynamic Effects of Ciprofloxacin, Fleroxacin and Lomefloxacin in vivo and in vitro

Pharmacodynamic effects of subinhibitory concentrations of beta-lactam antibiotics in vitro

The postantifungal effect (PAFE) of antimycotics on oral C. albicans isolates and its impact on candidal adhesion

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