研究のタイプ: 医学/生物学の研究 (experimental study)

[大腸菌および緑膿菌の増殖および抗生物質感受性に対する超低周波電磁界の影響評価] med./bio.

Evaluations of the Effects of Extremely Low-Frequency Electromagnetic Fields on Growth and Antibiotic Susceptibility of Escherichia coli and Pseudomonas aeruginosa.

掲載誌: Int J Microbiol 2012: 587293

この研究は、超低周波電磁界(2 mT、50 Hz)へのばく露が、大腸菌ATCC25922および緑膿菌ATCC27853の増殖速度と抗生物質感受性に与える影響を調べた。両方の菌株について、対照群磁界ばく露群、作用閾値下濃度のカナマイシン(1 μg/ mL)またはアミカシン(0.5 μg/ mL)の存在下の磁界ばく露群、それぞれの薬物単独投与群を用意した。インキュベーション中の磁界ばく露は最大24時間とした。その結果、4、6、および8時間のインキュベーションにおいて、磁界ばく露群では、対照群に比べ、細胞数の有意な減少が見られた; 24時間のインキュベーションにおいて、対照群と比較して、磁界ばく露群での細胞増加割合が増加した(緑膿菌は約42 %、大腸菌は約5 %);このことは、進行性の適応反応を示唆すると著者は考察した;対照的に、両方の細菌において、抗生物質存在下のばく露群と対照群の間には、抗生物質感受性および増殖速度に顕著な違いは見られなかった、と報告している。

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研究目的(著者による)

To investigate the effects of an exposure to extremely low-frequency magnetic fields on the growth rate and antibiotic sensitivity of the bacteria strains Escherichia coli and Pseudomonas aeruginosa.

詳細情報

The growth rates were determined for following groups: 1.) control group, 2.) expoure group, 3.) kanamycin, 4.) kanamycin + exposure, and 5.) amikacin + exposure.
The antibiotic susceptibility was determined by the minimal inhibitory concentration (the dilution value at which no visible growth occurred in the bacteria) of the two bacteria strains in presence and absence of an extremely low-frequency magnetic field. Following antibiotics were tested: kanamycin, amikacin, ampicillin, ceftazidime, levofloxacin, cefazolin, ceftriaxone, and moxalactam.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
ばく露時間: continuous for up to 24 h

General information

Following groups were investigated: 1.) control group 2.) expoure group 3.) kanamycin 4.) kanamycin + exposure 5.) amikacin + exposure

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for up to 24 h
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 pair of Helmholtz coils with a mean radius of 13 ± 0.5 cm; each coil consisted of 800 turns of 2 mm² wire; coils spaced vertically 13.5 ± 0.5 cm apart; field uniformity better than 1% in the exposure area; four Falcon multiwell plates with 96 wells or twelve 20 ml glas tubes exposed simultaneously; exposure system placed inside an incubator with constant temperature of 37 ± 0.3 °C
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 2 mT - 測定値 - -

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
調査の時期:
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

No remarkable differences were found in the antibiotic susceptibility and on the growth rates of both bacteria comparing the exposed group (group 2) with the control group (group 1).
However, exposure to an extremely low-frequency magnetic field showed a significant effect on the growth rate of both strains when incubated in the presence of subinhibitory concentrations of kanamycin (1 µg/ml, group 4) and amikacin (O.5 µg/ml, group 5). In particular, at 4, 6, and 8 h exposure the number of cells was significantly decreased in exposed bacteria compared with the control (group 3). Additionally, at 24 h exposure, the percentage of cells increased in treated groups with respect to the control group suggesting a progressive adaptive response.

研究の種別:

研究助成

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