Topoisomerase IV; DNA gyrase

克林沙星对 parC-gyrA 突变株中的肺炎链球菌有效，最低抑菌浓度 (MIC) 为 1 μg/ml[2]。
盐酸克林沙星对改变靶标的金黄色葡萄球菌突变株具有抗菌特性。它对野生型金黄色葡萄球菌、gyrA 突变型金黄色葡萄球菌和 gyrA 突变型金黄色葡萄球菌的 MIC 值分别为 0.016 µg/ml、0.063 µg/ml 和 0.915 µg/ml[3]。

对青霉素耐药的克林沙星肺炎球菌脑膜炎对兔子模型中的克林沙星治疗反应良好。
当与 CS 菌株 (2349) 一起使用时，克林沙星在 6 小时内产生初始减少（克林沙星 MIC=0.12 μg/ml），剂量为10毫克/公斤和20毫克/公斤。 24 小时时平均 log cfu/ml 的最终降低分别为 22.30 和 23.83。此时两者均具有杀菌作用，但随后会重新生长。但在兔脑膜炎模型中，即使每天 20 mg/kg，克林沙星 (MIC=0.5 μg/ml) 也不会降低细菌滴度[3]。这是因为 CR 菌株 (4371) 表现出这种特性。

研究了15种喹诺酮类药物对grlA和gyrA突变株的抗菌活性和靶向抑制作用。分别用诺氟沙星和纳地沙星从野生型金黄色葡萄球菌MS5935中筛选得到菌株。大多数喹诺酮类药物对这两种突变株的抗菌活性均低于对野生型菌株的抗菌活性。gyrA突变株与grlA突变株的MIC比率（MIC比率）在0.125至4之间变化。喹诺酮类药物对拓扑异构酶IV的50%抑制浓度（IC50）与对DNA旋转酶的IC50比值也在0.177至5.52之间变化。观察到MIC比值与IC50比值之间存在显著相关性（r=0.919；P<0.001）。这些结果表明，喹诺酮类药物对野生型菌株的抗菌活性不仅涉及拓扑异构酶IV的抑制，还涉及DNA旋转酶的抑制，野生型菌株中的靶点偏好可以通过MIC比值来预测。根据MIC比值，喹诺酮类药物分为三类。I型喹诺酮类药物（诺氟沙星、依诺沙星、氟罗沙星、环丙沙星、洛美沙星、托氟沙星、格列帕沙星、氧氟沙星和左氧氟沙星）的MIC比值<1，II型喹诺酮类药（司帕沙星和纳地沙星）的MIC比>1，III型喹诺酮类药品（加替沙星、帕珠沙星、莫西沙星和克林氟沙星）的MIC比率为1。I型和II型喹诺酮类药物似乎分别更喜欢拓扑异构酶IV和DNA旋转酶。III型喹诺酮类药物似乎在细菌细胞中以几乎相同的水平靶向这两种酶（这种现象称为双重靶向特性），它们的IC50比约为2[1]。

The increasing incidence of ciprofloxacin resistance in Streptococcus pneumoniae may limit the efficacy of the new quinolones in difficult-to-treat infections such as meningitis. The aim of the present study was to determine the efficacy of clinafloxacin alone and in combination with teicoplanin and rifampin in the therapy of ciprofloxacin-susceptible and ciprofloxacin-resistant pneumococcal meningitis in rabbits. When used against a penicillin-resistant ciprofloxacin-susceptible strain (Clinafloxacin MIC 0.12 microg/ml), clinafloxacin at a dose of 20 mg/kg per day b.i.d. decreased bacterial concentration by -5.10 log cfu/ml at 24 hr. Combinations did not improve activity. The same clinafloxacin schedule against a penicillin- and ciprofloxacin-resistant strain (Clinafloxacin MIC 0.5 microg/ml) was totally ineffective. Our data suggest that a moderate decrease in quinolone susceptibility, as indicated by the detection of any degree of ciprofloxacin resistance, may render these antibiotics unsuitable for the management of pneumococcal meningitis[3].

[1]. Target preference of 15 quinolones against Staphylococcus aureus, based on antibacterial activities and target inhibition.Antimicrob Agents Chemother. 2001 Dec;45(12):3544-7.

[2]. DNA Gyrase and Topoisomerase IV Mutations and their effect on Quinolones Resistant Proteus mirabilis among UTIs Patients. Pak J Med Sci. Sep-Oct 2020;36(6):1234-1240.

[3]. Experimental study of clinafloxacin alone and in combination in the treatment of ciprofloxacin-susceptible and -resistant pneumococcal meningitis.Microb Drug Resist. 2003;9 Suppl 1:S53-9.

7-(3-amino-1-pyrrolidinyl)-8-chloro-1-cyclopropyl-6-fluoro-4-oxo-3-quinolinecarboxylic acid is a member of quinolines. Clinafloxacin is a fluoroquinolone antibacterial currently under research. It has been proven to present good antibiotic properties. However, its approval and release have been halted due to the presence of serious side effects.

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Objective: This study aimed to highlight the importance of mutations within Proteus mirabilis genome that are related to fluoroquinolone resistance. Methods: This is a cross sectional study performed in different teaching hospitals in Khartoum State from June 2016 to May 2017. A total of (120) P mirabilis isolates from patients with symptoms of UTIs attending different hospitals in Khartoum State were examined. First, modified Kurby Bauer method was performed for phenotypical detection of resistant isolates. Then polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequencing were applied for detection of mutations in GyrA, GyrB, ParC and ParE genes of isolates. Results: P. mirabilis showed 30% resistance to ciprofloxacin. All samples revealed mutation at (serine 83) of GyrA and (serine 84) of ParC by Hinf1 restriction endonuclease digestion. Sequencing was performed for 12 samples. For each gene, two resistant and one susceptible strains were randomly selected. The mutations associated with ciprofloxacin resistant P. mirabilis were as follows; (1/3) GyrA (Ser 83 to Ile) and (2/3) ParC (Ser 81 to Ile). Also it revealed silent mutations at codons of GyrB 474 leucine (3/3), 585 valine (2/3), 612 histidine (1/3) and 639 asparagine (1/3) and ParE 469 isoleucine (2/3), 531 aspartic (2/3) and 533 glycine (1/3). Conclusions: Ciprofloxacin resistance in P. mirabilis could be monitored through detection of mutations within DNA gyrase (encoded by gyrA and gyrB) and topoisomerase IV (encoded by parC and parE).[2]

C17H18CL2FN3O3

402.24752

401.07

C, 50.76; H, 4.51; Cl, 17.63; F, 4.72; N, 10.45; O, 11.93

105956-99-8

105956-97-6; 105956-99-8 (HCl)

60062

Solid powder

1.573 g/cm3

592.3ºCat 760 mmHg

162-168°C

312ºC

3.931

88.56

3

7

3

26

626

0

C1CC1N2C=C(C(=O)C3=C2C(=C(C(=C3)F)N4CCC(C4)N)Cl)C(=O)O.Cl

BMACYHMTJHBPOX-UHFFFAOYSA-N

InChI=1S/C17H17ClFN3O3.ClH/c18-13-14-10(5-12(19)15(13)21-4-3-8(20)6-21)16(23)11(17(24)25)7-22(14)9-1-2-9;/h5,7-9H,1-4,6,20H2,(H,24,25);1H

7-(3-aminopyrrolidin-1-yl)-8-chloro-1-cyclopropyl-6-fluoro-4-oxoquinoline-3-carboxylic acid;hydrochloride

CI-960; PD-127391; AM-109; CI960; PD127391; AM109; Clinafloxacin hydrochloride; Clinafloxacin HCl; CI-960 HCl; UNII-G17M59V0FY ;CI 960 HCl

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

5%TFA: ~3.02 mg/mL
DMSO: ~0.03 mg/mL (~0.08 mM)

注意: 如下所列的是一些常用的体内动物实验溶解配方，主要用于溶解难溶或不溶于水的产品（水溶度<1 mg/mL）。 建议您先取少量样品进行尝试，如该配方可行，再根据实验需求增加样品量。

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注射用配方1: DMSO : Tween 80： Saline = 10 : 5 : 85 (如： 100 μL DMSO → 50 μL Tween 80 → 850 μL Saline)
*生理盐水/Saline的制备：将0.9g氯化钠/NaCl溶解在100 mL ddH ₂ O中，得到澄清溶液。
注射用配方 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL DMSO → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)
注射用配方 3: DMSO : Corn oil = 10 : 90 (如： 100 μL DMSO → 900 μL Corn oil)
示例: 以注射用配方 3 (DMSO : Corn oil = 10 : 90) 为例说明, 如果要配制 1 mL 2.5 mg/mL的工作液, 您可以取 100 μL 25 mg/mL 澄清的 DMSO 储备液，加到 900 μL Corn oil/玉米油中, 混合均匀。

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注射用配方 4: DMSO : 20% SBE-β-CD in Saline = 10 : 90 [如：100 μL DMSO → 900 μL (20% SBE-β-CD in Saline)]
*20% SBE-β-CD in Saline的制备（4°C，储存1周）：将2g SBE-β-CD (磺丁基-β-环糊精) 溶解于10mL生理盐水中，得到澄清溶液。
注射用配方 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (如： 500 μL 2-Hydroxypropyl-β-cyclodextrin (羟丙基环胡精)→ 500 μL Saline)
注射用配方 6: DMSO : PEG300 : Castor oil : Saline = 5 : 10 : 20 : 65 (如： 50 μL DMSO → 100 μL PEG300 → 200 μL Castor oil → 650 μL Saline)
注射用配方 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (如： 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
注射用配方 8: 溶解于Cremophor/Ethanol (50 : 50), 然后用生理盐水稀释。
注射用配方 9: EtOH : Corn oil = 10 : 90 (如： 100 μL EtOH → 900 μL Corn oil)
注射用配方 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL EtOH → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)

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口服配方 1: 悬浮于0.5% CMC Na (羧甲基纤维素钠)
口服配方 2: 悬浮于0.5% Carboxymethyl cellulose (羧甲基纤维素)
示例: 以口服配方 1 (悬浮于 0.5% CMC Na)为例说明, 如果要配制 100 mL 2.5 mg/mL 的工作液, 您可以先取0.5g CMC Na并将其溶解于100mL ddH2O中，得到0.5%CMC-Na澄清溶液；然后将250 mg待测化合物加到100 mL前述 0.5%CMC Na溶液中，得到悬浮液。

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口服配方 3: 溶解于 PEG400 (聚乙二醇400)
口服配方 4: 悬浮于0.2% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 5: 溶解于0.25% Tween 80 and 0.5% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 6: 做成粉末与食物混合

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注意: 以上为较为常见方法，仅供参考， InvivoChem并未独立验证这些配方的准确性。具体溶剂的选择首先应参照文献已报道溶解方法、配方或剂型，对于某些尚未有文献报道溶解方法的化合物，需通过前期实验来确定（建议先取少量样品进行尝试），包括产品的溶解情况、梯度设置、动物的耐受性等。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。