Comparison of in vitro Antimicrobial Activities of Tc-99m Infecton and Ciprofloxacin

Tc-99m Infecton과 Ciprofloxacin의 생체외 항균력 비교

Purpose: There was little evidence that Tc-99m labeled ciprofloxacin (Infecton) located inside of bacteria. Antimicrobial activity of Infecton could be an indirect evidence of its location. We compared in vitro antimicrobial activities of Infecton and ciprofloxacin. Materials and methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Infecton and ciprofloxacin against three standard strains of bacteria, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 were measured using modified broth macrodilution techniques and pour plate methods, respectively. Data were expressed as mean${\pm}$SE (range). Results: MICs of Infecton and ciprofloxacin were $1.12{\pm}0.20\;(0.8{\sim}1.6){\mu}g/ml\;and\;0.35{\pm}0.04\;(0.2{\sim}0.4){\mu}g/ml$ for S. aureus, $0.03{\pm}0.005\;(0.025{\sim}0.05){\mu}g/ml\;and\;0.011{\pm}0.001\;(0.006{\sim}0.012){\mu}g/ml$ for E. coil, and $0.96{\pm}0.16\;(0.8{\sim}1.6){\mu}g/ml)\;and\;0.56{\pm}0.098\;(0.4{\sim}0.8){\mu}g/ml$ for P. aeruginosa, respectively. MBCs of Infecton and ciprofloxacin were $2.56{\pm}0.39\;(1.6{\sim}3.2){\mu}g/ml\;and\;0.88{\pm}0.2\;(0.4{\sim}1.6){\mu}g/ml$ for S. aureus, $0.04{\pm}0.05\;(0.025{\pm}0.05){\mu}g/ml\;and\;0.02{\pm}0.01\;(0.025{\sim}0.05)\;{\sim}g/ml$ for E coli, and $2.24{\pm}0.39\;(1.6{\sim}3.2){\mu}g/ml\;and\;1.44{\pm}0.16\;(0.8{\sim}1.6){\mu}g/ml$ for P. aeruginosa, respectively. Conclusion: Although both MICs and UBCs of Infecton were higher than those of ciprofloxacin, all three standard bacterial strains were sensitive to Infecton. It could be an indirect evidence that Tc-99m Infecton be a specific imaging agent for bacterial infection.

목적: 새로운 감염영상법인 Tc-99m Infecton 스캔은 4-fluoroquinolone 계열의 광범위 항생제인 ciprofloxacin의 유도체를 이용한 것인데 이에 사용되는 Infecton의 항균력에 대한 연구는 접하기 어렵다. 저자들은 표준 균주에서의 Infecton의 항균력을 ciprofloxacin과 비교 분석하고자 본 연구를 시행하였다. 대상 및 방법: Infecton의 표준 균주 3종 (Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, 및 Pseudomonas aeruginosa ATCC 27853)에 대한 최소발육억제농도(minimum inhibitory concentration, MIC)와 최소살균농도 (minimum bactericidal concentration, MBC)를 검사하여, ciprofloxacin과 비교하였다. Ciprofloxacin과 Infecton의 MIC와 MBC는 표준균주에서 5회 검사하여 결과를 평균${\pm}$표준오차(범위)로 나타내었다. 결과: Infecton과 ciprofloxacin 의 MIC 결과는 S. aureus ATCC 29213에서 각각 $1.12{\pm}0.2\;(0.8{\sim}1.6){\mu}g/ml$이었으며 (p=0.016), E. coli ATCC 25922 에서는 각각 $0.03{\pm}0.005\;(0.025{\sim}0.05){\mu}g/ml,\;0.011{\pm}0.001\;(0.006{\sim}0.012){\mu}g/ml$이었고(p=0.007), P. aeruginosa ATCC 27853에 대해서는 각각 $0.96{\pm}0.16\;(0.8{\sim}1.6){\mu}g/ml,\;0.56{\pm}0.1\;(0.4{\sim}0.8){\mu}g/ml$로(p=0.66), 표준 균주 3종 모두에서 Infecton의 MIC가 ciprofloxacin 보다 $2{\sim}4$배 더 높았으나, 미국 National Committee for Clinical Laboratory Standards (NCCLS)가 정한 바에 의한 MIC 정도관리범위 내의 농도을 보이고 있었다. 또한, Infecton 과 ciprofloxacin의 MBC 결과는 S. aureus ATCC 29213에서 각각 $2.6{\pm}0.4\;(1.6{\sim}3.2){\mu}g/ml,\;0.88{\pm}0.19\;(0.4{\sim}1.6){\mu}g/ml$였고(p=0.009), E. coli ATCC 25922에서는 각각 $0.035{\pm}0.006\;(0.025{\sim}0.05){\mu}g/ml,\;0.02{\pm}0.008\;(0.025{\sim}0.05){\mu}g/ml$ 였으며 (p=0.114), p. aeruginosa ATCC 27853에서는 각각 $2.2{\pm}0.4\;(1.6{\sim}3.2){\mu}g/ml$와 $1.4{\pm}0.2\;(0.8{\sim}1.6){\mu}g/ml$로서(p=0.16), 표준균주 3종 모두에서 Infecton의 MBC 또한 ciprofloxacin에 비해 $2{\sim}4$배가 높았다. 결론: Tc-99m Infecton은 ciprofloxacin 보다는 약하였지만 표준균주에 대해 생체외 항균력을 보였다.