[Determination of the isoelectric point of beta-lactamases isolated from 67 Klebsiella oxytoca strains and phenotype behaviour against eight beta-lactam antibiotics].
[Determination of the isoelectric point of beta-lactamases isolated from 67 Klebsiella oxytoca strains and phenotype behaviour against eight beta-lactam antibiotics].
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67株产酸克雷伯菌菌株中β-内酰胺酶等电点的测定及对8种β-内酰胺类抗生素的表型行为[J].
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发表时间：
1993
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通讯作者：
E. Lagier
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作者：
H. Chardon;C. Pachetti;L. Collet;O. Bellon;E. Lagier
产氧克雷伯菌通过产生染色体β -内酰胺酶对氨基霉素和羧基青霉素具有天然抗性，但对第三代头孢菌素敏感。第三代头孢菌素的活性可能由于染色体编码的β -内酰胺酶或广谱β -内酰胺酶的过量产生而降低。在普罗旺斯艾克斯医院（法国）很少发现这些活性改变。1986年至1991年期间，由于染色体编码的β -内酰胺酶过量产生，氧曲菌的抗性活性改变率为3.6%，而获得广谱β -内酰胺酶的抗性活性改变率为0.7%。我们用等电聚焦法测定了67株赤霉β -内酰胺酶的等电点（pI），用圆盘扩散法研究了8种β -内酰胺酶的活性。研究了51株野生菌株、14株高产菌株（包括2株体外突变菌株）和2株广谱β -内酰胺酶菌株。除了2株有2条带状带（pl 5.4 + 6.3和pl 5.6 + 7.7）外，每个野生菌株只有1条带状带。其他菌株的等电点在pl 5.25 ~ pl 8.2之间；13 pl 5.25；4 pl 5.6；4 pl 6.3；2 pl 6.6；2 pl 8.1和2 pl 8.2。在染色体编码β -内酰胺酶过量产生的菌株中，我们在每个提取物中观察到几个条带，仅考虑主要条带。β -内酰胺酶过量产生的离体突变菌株的等电点与野生菌株相同。我们观察到3 pl: 5.25 - 1 pl: 5.6 - 3 pl 6.3和5 pl 7.7。（摘要删节250字）
Klebsiella oxytoca is naturally resistant to aminopenicillins and carboxypenicillins by production of a chromosomal beta-lactamase but susceptible to third generation cephalosporins. The third generation cephalosporins activity may be reduced by: overproduction of the chromosomally encoded beta-lactamase or an extended-spectrum beta-lactamase. These activity modification are rarely found in the hospital of Aix-en-Provence (France). The activity modification rate of K. oxytoca resistant by one of these mechanisms between 1986 and 1991 are 3.6% for chromosomally encoded beta-lactamase overproduction and 0.7% for acquisition of an extended-spectrum beta-lactamase. We have determined the isoelectric point (pI) by isoelectrofocusing of the beta-lactamases isolated from 67 K. oxytoca and the activity of 8 beta-lactams has been studied by disk-diffusion. 51 wild strains, 14 overproducing strains (including 2 in vitro mutants) and 2 strains with extended-spectrum beta-lactamase were studied. For every wild strain, we observed only one band except for two strains with two bands (pl 5.4 + 6.3 and pl 5.6 + 7.7). The isoelectric points for the other strains are comprised between pl 5.25 and pl 8.2: 22 pl 7.7; 13 pl 5.25; 4 pl 5.6; 4 pl 6.3; 2 pl 6.6; 2 pl 8.1 and 2 pl 8.2. In the strains with chromosomally encoded beta-lactamase overproduction we observed several bands in each extract and only the major band was considered. The isoelectric point of in vitro mutant strains with beta-lactamase overproduction was the same that the wild strains. We observed 3 pl: 5.25 - 1 pl: 5.6 - 3 pl 6.3 and 5 pl 7.7.(ABSTRACT TRUNCATED AT 250 WORDS)