Abstract：
This study was conducted to determine the biofilm formation of coagulase negative Staphylococcus species (CoNS) isolated from patients with catheter related blood stream infection (CRBSI) and colonized central venous catheters (CVC) and their antibiotic susceptibility patterns and in situ biofilm formation of CVC tips.
Eighty-two CoNS isolated from intensive care unit (ICU) patients with CRBSI (n = 8) or colonized CVC (n = 74) were included. Species identification and antibiotic susceptibility test were done. All isolates were screened for biofilm formation using crystal violet and 3-(4,5-dimethylthiazole-2-yl)-2-5-diphenyl-2H-tetrazolium bromide (MTT) assays and categorized as strong or moderate biofilm formers. CVC tips were subjected to crystal violet stain and scanning electron microscopy (SEM) to detect in-situ biofilm formation.
Staphylococcus haemolyticus (n = 34; 41%) was the commonest to cause both CRBSI and CVC colonization. All 82 CoNS produced biofilms. Among them 77 (93.90%) were strong biofilm formers including all from CRBSI patients and 05 (6.10%) were moderate biofilm formers as detected by both methods. SEM showed bacteria adhered to surfaces of CVC tips with microbial-aggregates embedded in extracellular matrix. Mean crystal violet absorbance of CVC from CRBSI patients (0.6628) was significantly higher than colonized CVC (mean value 0.5592) (p = 0.030). S. haemolyticus showed higher resistance to cloxacillin compared to other CoNS (p = 0.039).
Majority of CoNS isolated were strong biofilm formers. In-situ biofilm formation on CVC tips were significantly evident in CRBSI patients compared to CVC colonized patients. S. haemolyticus is the commonest to cause both CRBSI and CVC colonization and shows significantly higher cloxacillin resistance rate.
Eighty-two CoNS isolated from intensive care unit (ICU) patients with CRBSI (n = 8) or colonized CVC (n = 74) were included. Species identification and antibiotic susceptibility test were done. All isolates were screened for biofilm formation using crystal violet and 3-(4,5-dimethylthiazole-2-yl)-2-5-diphenyl-2H-tetrazolium bromide (MTT) assays and categorized as strong or moderate biofilm formers. CVC tips were subjected to crystal violet stain and scanning electron microscopy (SEM) to detect in-situ biofilm formation.
Staphylococcus haemolyticus (n = 34; 41%) was the commonest to cause both CRBSI and CVC colonization. All 82 CoNS produced biofilms. Among them 77 (93.90%) were strong biofilm formers including all from CRBSI patients and 05 (6.10%) were moderate biofilm formers as detected by both methods. SEM showed bacteria adhered to surfaces of CVC tips with microbial-aggregates embedded in extracellular matrix. Mean crystal violet absorbance of CVC from CRBSI patients (0.6628) was significantly higher than colonized CVC (mean value 0.5592) (p = 0.030). S. haemolyticus showed higher resistance to cloxacillin compared to other CoNS (p = 0.039).
Majority of CoNS isolated were strong biofilm formers. In-situ biofilm formation on CVC tips were significantly evident in CRBSI patients compared to CVC colonized patients. S. haemolyticus is the commonest to cause both CRBSI and CVC colonization and shows significantly higher cloxacillin resistance rate.
摘要：
目的：本研究旨在确定从导管相关性血流感染（CRBSI）和定植中心静脉导管（CVC）患者中分离的凝固酶阴性葡萄球菌（CoNS）的生物膜形成及其抗生素敏感性模式和CVC尖端的原位生物膜形成。
方法：纳入82例分离自重症监护病房（ICU）CRBSI（n=8）或定植CVC（n=74）患者的CoNS。进行物种鉴定和抗生素敏感性试验。使用结晶紫和3-(4,5-二甲基噻唑-2-基)-2-5-二苯基-2H-四唑溴化物(MTT)测定筛选所有分离物的生物膜形成,并分类为强或中等生物膜形成物。对CVC尖端进行结晶紫染色和扫描电子显微镜(SEM)以检测原位生物膜形成。
结果：溶血葡萄球菌（n=34;41％）是引起CRBSI和CVC定植的最常见原因。所有82个CoNS产生生物膜。其中77（93.90％）是强生物膜形成剂，包括全部来自CRBSI患者，而05（6.10％）是中度生物膜形成剂，这两种方法均检测到。SEM显示细菌粘附在CVC尖端的表面，微生物聚集体嵌入细胞外基质中。CRBSI患者CVC的平均结晶紫吸光度(0.6628)显著高于定植CVC(平均值0.5592)(p=0.030)。与其他CoNS相比，溶血链球菌对氯唑西林的耐药性更高（p=0.039）。
结论：大多数分离的CoNS是强生物膜形成者。与CVC定植的患者相比，CRBSI患者中CVC尖端上的原位生物膜形成显着明显。溶血链球菌是引起CRBSI和CVC定殖的最常见的,并且显示显著更高的氯唑西林耐药率。
方法：纳入82例分离自重症监护病房（ICU）CRBSI（n=8）或定植CVC（n=74）患者的CoNS。进行物种鉴定和抗生素敏感性试验。使用结晶紫和3-(4,5-二甲基噻唑-2-基)-2-5-二苯基-2H-四唑溴化物(MTT)测定筛选所有分离物的生物膜形成,并分类为强或中等生物膜形成物。对CVC尖端进行结晶紫染色和扫描电子显微镜(SEM)以检测原位生物膜形成。
结果：溶血葡萄球菌（n=34;41％）是引起CRBSI和CVC定植的最常见原因。所有82个CoNS产生生物膜。其中77（93.90％）是强生物膜形成剂，包括全部来自CRBSI患者，而05（6.10％）是中度生物膜形成剂，这两种方法均检测到。SEM显示细菌粘附在CVC尖端的表面，微生物聚集体嵌入细胞外基质中。CRBSI患者CVC的平均结晶紫吸光度(0.6628)显著高于定植CVC(平均值0.5592)(p=0.030)。与其他CoNS相比，溶血链球菌对氯唑西林的耐药性更高（p=0.039）。
结论：大多数分离的CoNS是强生物膜形成者。与CVC定植的患者相比，CRBSI患者中CVC尖端上的原位生物膜形成显着明显。溶血链球菌是引起CRBSI和CVC定殖的最常见的,并且显示显著更高的氯唑西林耐药率。
