- 期刊
B群鏈球菌增菌後再培養之檢出率
Detection of Group B Streptococci by Quantitative Culture
摘要
目的：美國在近三十幾年來，B群鏈球菌(Group B Streptococcus; GBS; Streptococcus agalactiae)感染一直是導致新生兒早發性疾病的首因。為了預防新生兒遭受GBS感染並降低罹病與死亡率，我們必須以更精確及有效的方法篩檢出孕婦是否為GBS帶菌者，並在生產時提供她們適當的預防性抗生素。美國疾病管制局在2002年將1996年發行的「預防分娩時期受B群鏈球菌感染指引」改版後建議：除使用選擇性肉湯培養基(selective broth medium)來提高懷孕35至37週孕婦之陰道及直腸GBS移生(colonization)篩檢的陽性率外，為了對penicillin過敏的孕婦提供新的預防性抗生素用藥策略，分離出的GBS須進行抗生素感受性試驗。方法：我們為了評估使用選擇性培養基(Lim broth)後，篩檢陽性率提高多少，將台北市立聯合醫院仁愛院區檢驗室原本所使用的直接將檢體接種在血液培養基上，與遵照指引的建議方式先將檢體接種在選擇性肉湯培養基增菌後再次培養至血液培養基上之兩種培養方法的陽性率做比較。除此之外，對於確認為GBS的菌落加做penicillin、ampicillin、cefotaxim、erythromycin、clindamycin、levofloxacin及vancomycin的藥物感受性試驗。結果：台北市立聯合醫院微生物檢驗室自2006年元月至十二月接受來自各院區579件篩檢GBS的檢體。以直接接種在血液培養基的方法，或經由選擇性肉湯培養基(Lim broth)增菌後的方法，兩者合計分離出120件(20.7%)GBS陽性的檢體。這其中必須經由選擇性肉湯培養基(Lim broth)增菌後方可分離出GBS的有47件(8.1%)，而我們未發現僅從直接接種在血液培養基才分離出GBS的情形。此外我們將分離出的120株GBS做藥物感受性試驗試驗，它們對penicillin、ampicillin及vancomycin並無抗藥性(0/120)，對cefotaxim及levofloxacin之抗藥性均為0.8%(1/120)，對clindamycin及erythromycin的抗藥性各為35%(42/120)及27.5%(33/120)。結論：由上述的資料可知檢驗室遵照美國疾病管制局對GBS篩檢的建議方式來操作，確實可提高GBS篩檢的陽性率（12.6%提高至20.7%）；並且針對預防新生兒早發性GBS感染，penicillin仍是分娩時所使用預防性抗生素的首選藥物。
並列摘要
Group B Streptococcus (GBS; Streptococcus agalactiae) has been the leadingcause of early-onset neonatal disease in the United States for more than 30 years. To prevent the newborn from becoming infected with neonatal GBS and in order to reduce neonatal morbidity and mortality, it is necessary to use a more sensitive and effective approach to screening for GBS carriage among all pregnant women. This allows the provision of suitable intrapartum antibiotic prophylaxis. The 2002 revised guidelines of the Centers for Disease Control and Prevention (CDC) for Prevention of Perinatal Group B Streptococcal Disease recommended the use of a selective broth medium. This provides an improved detection level for vaginal and rectal GBS colonization among pregnant women and should be carried out between week 35 and week 37 of gestation. Methods: In order to evaluate this recommendation in our laboratory, we compared the positive rate for GBS using enrichment by the selective broth medium method (Lim broth) against our current method of direct plating onto blood agar plates. Additionally, susceptibility testing was carried out using penicillin, ampicillin, erythromycin, clindamycin, cefotaxime, levofloxacin and vancomycin on the confirmed GBS0 solates. Results: From January 2006 to December 2006, the Microbiology Section of Taipei City Hospital screened 579 specimens for GBS carriage and GBS were recovered from 120 of the 579 specimens (20.7%) by one or both culture techniques. There were 47(8.1%) positive GBS specimens recovered using LIM broth only and no positive GBS specimens recovered using direct plating onto blood agar plates only. Among the 120 GBS isolates, none were resistant to penicillin, ampicillin or vancomycin (0/120), 0.8% were resistant to cefotaxime (1/120), 0.8% were resistant to levofloxacin (1/120), 27.5% were resistant to erythromycin (33/120) and 35% were resistant to clindamycin (42/120). Conclusion: Based on the above results, we found that following the CDC guidelines when screening for GBS carriage definitely enhanced the detection rate and that penicillin remains the drug of choice for intrapartum antibiotic prophylaxis.