Department of Biological Science, Faculty of Science, Thompson Rivers University, Kamloops.
Can J Infect Dis Med Microbiol. 2012 Winter;23(4):196-8. doi: 10.1155/2012/540127.
Intrapartum antibiotic prophylaxis (IAP) is recommended for pregnant women who test positive for group B Streptococcus (GBS) in their genitourinary tract to prevent GBS-induced neonatal sepsis. Penicillin G is used as the primary antibiotic, and clindamycin or erythromycin as the secondary, if allergies exist. Decreased susceptibility to penicillin G has occasionally been reported; however, clindamycin and erythromycin resistance is on the rise and is causing concern over the use of clindamycin and erythromycin IAP.
Antibiotic resistance was characterized phenotypically using a D-Test for erythromycin and clindamycin, while an E-Test (E-strip) was used for penicillin G. GBS was isolated from vaginal-rectal swabs and serologically confirmed using Prolex (Pro-Lab Diagnostics, Canada) streptococcal grouping reagents. Susceptibility testing of isolates was performed according to the Clinical Laboratory Standards Institute guidelines.
All 158 isolates were penicillin G sensitive. Inducible macrolide-lincosamide-streptogramin B (MLSB) resistance was observed in 13.9% of isolates. Constitutive MLSB resistance was observed in 12.7% of isolates. M phenotype resistance was observed in 6.3% of isolates. In total, erythromycin resistance was present in 32.9% of the GBS isolates, while clindamycin resistance was present in 26.6%.
The sampled GBS population showed no sign of reduced penicillin susceptibility, with all being well under susceptible minimum inhibitory concentration values. These data are congruent with the large body of evidence showing that penicillin G remains the most reliable clinical antibiotic for IAP. Clindamycin and erythromycin resistance was higher than expected, contributing to a growing body of evidence that suggests the re-evaluation of clindamycin and erythromycin IAP is warranted.
对于生殖道检测出 B 组链球菌（GBS）阳性的孕妇，推荐使用围产期抗生素预防（IAP）来预防 GBS 引起的新生儿败血症。青霉素 G 是首选抗生素，如果存在过敏反应，则使用克林霉素或红霉素作为替代药物。偶尔有报道称青霉素 G 的敏感性降低；然而，克林霉素和红霉素的耐药性正在上升，这引起了人们对使用克林霉素和红霉素 IAP 的关注。
使用 D-测试法对红霉素和克林霉素进行表型耐药性特征分析，同时使用 E-测试（E-strip）法对青霉素 G 进行测试。从阴道直肠拭子中分离出 GBS，并使用 Prolex（Pro-Lab Diagnostics，加拿大）链球菌分组试剂进行血清学确认。根据临床实验室标准化协会指南进行分离株的药敏试验。
所有 158 株分离株均对青霉素 G 敏感。诱导型大环内酯-林可酰胺-链阳菌素 B（MLSB）耐药性在 13.9%的分离株中观察到。固有 MLSB 耐药性在 12.7%的分离株中观察到。M 表型耐药性在 6.3%的分离株中观察到。总的来说，158 株 GBS 分离株中有 32.9%对红霉素耐药，而克林霉素耐药率为 26.6%。
所采样的 GBS 群体没有出现青霉素敏感性降低的迹象，所有分离株的最低抑菌浓度值均远低于敏感范围。这些数据与大量证据一致，表明青霉素 G 仍然是 IAP 最可靠的临床抗生素。克林霉素和红霉素耐药性高于预期，这进一步证明有必要重新评估克林霉素和红霉素 IAP。
