Extensively drug-resistant Stenotrophomonas maltophilia in a tertiary care hospital in Taiwan: microbiologic characteristics, clinical features, and outcomes

A retrospective study was performed in a university-affiliated referral center from year 1999 to year 2004 to understand the trend of resistance in Stenotrophomonas maltophilia isolates associated with nosocomial infections and describe the emergence of an extensively drug-resistant S. maltophilia (XDRSM). A 49% increase in all types of nosocomial infections and an 85% increase in nosocomial bloodstream infections caused by S. maltophilia were noted over the 5-year period. Trends of resistance to 7 antimicrobial agents against S. maltophilia remained stable. Seventeen patients had positive cultures of XDRSM in the year 2004, including 6 with pneumonia and 1 with biliary tract infection, and the other 10 patients had XDRSM colonization. Twelve patients (70.6%) had positive cultures of non-XDRSM prior to the acquisition of XDRSM. The mortality rate of patients with XDRSM infection was higher than those with colonization (85.7% versus 10%, P = 0.004). XDRSM infection, presence of shock, and the number of dysfunctional organ systems at the time of XDRSM isolation were significantly associated with in-hospital mortality (P < 0.05). Genotyping of the 17 XDRSM isolates revealed 16 different clones. All the isolates tested possessed class 1 integron and formed biofilms and melanin. The high genotypic heterogeneity among XDRSM isolates was indicative of the polyclonal nature of emergence of these resistant bacteria. Majority of patients had positive cultures of non-XDRSM prior to the acquisition of XDRSM, indicating that the use of antibiotics might have resulted in selection of XDRSM.     

Screening of the antibacterial effects of a variety of essential oils on microorganisms responsible for respiratory infections

The aim of this study was to examine the cytotoxicity and the antibacterial effects of a variety of essential oils on major respiratory tract pathogens. The cytotoxicity of 13 essential oils was evaluated on Vero cells. The antibacterial activity was evaluated by the Kirby Bauer paper method, minimum inhibitory and bactericidal concentration against Streptococcus pyogenes, agalactiae, pneumoniae and Klebsiella pneumoniae, Haemophilus influenzae, Staphylococcus aureus and Stenotrophomonas maltophilia isolated from clinical specimens. The antibiotic sensitivity of these isolates was examined. Some oils showed inhibition of bacterial growth against most of the organisms examined. Cinnamon and thyme showed the strongest action followed by clove. The results reported in this paper indicate that thyme can be considered as a potential antimicrobial agent for the treatment of some respiratory tract infections in man.     

嗜麦芽窄食单胞菌下呼吸道感染30例临床分析

目的分析嗜麦芽窄食单胞菌下呼吸道感染的临床特点及对抗菌药物的敏感度。方法分析30例嗜麦芽窄食单胞菌下呼吸道感染的临床资料。采用VITK2全自动微生物分析系统鉴定细菌,K-B纸片法进行药物敏感试验。结果 30例中所有患者均有1种以上基础疾病,其中慢性阻塞性肺疾病急性加重最常见,占53.33%。临床表现为发热、咳嗽、咳痰,肺部闻及哮鸣音或湿啰音。X线胸片表现为两下肺片状和斑片状浸润性阴影,部分患者有胸腔积液。白细胞和中性粒细胞明显升高。药敏试验结果表明该菌株耐药率高,除亚胺培南外,对氨基糖苷类和三代头孢菌素类亦普遍耐药,耐药率〉80%,细菌对头孢哌酮/舒巴坦、复方新诺明、左氧氟沙星、米诺环素的敏感度分别为83.33%、86.67%、83.33%和90.00%。结论嗜麦芽窄食单胞菌下呼吸道感染易发生在患有多种基础疾病、使用广谱抗菌药物及侵入性操作患者,细菌耐药现象严重。临床上应尽早进行病原学检查,根据药敏试验结果 ,选用合适的抗菌药物。     

嗜麦芽窄食单胞菌感染的临床及抗菌药物应用分析

目的：分析和总结183株嗜麦芽窄食单胞菌的感染情况和对抗菌药的耐药情况,为临床预防和治疗该菌引起的感染提供依据。方法：对临床标本中分离的183株嗜麦芽窄食单胞菌进行细菌鉴定和药敏试验,复习有关临床资料,分析发病的危险因素。结果：183株嗜麦芽窄食单胞菌的检出标本以痰为主,占81.4%;居检出临床科室前4位的依次为呼吸科（31.8%）、老干部科（24.7%）、ICU病房（17.6%）、肿瘤科（5.9%）;高龄、侵入性诊疗操作、使用广谱抗菌药为嗜麦芽窄食单胞菌感染的危险因素,分别占80.0%、41.2%、100%;183株对常用抗菌药物耐药,敏感率超过50%的抗菌药依次为复方磺胺甲唑（SMZ-TMP）（80.3%）、头孢哌酮钠/舒巴坦（69.9%）、哌拉西林/他唑巴坦（64.5%）、环丙沙星（57.4%）。结论：嗜麦芽窄食单胞菌感染多发生在有各种基础疾病、免疫力低的患者,该菌耐药现象严重,治疗应根据药敏试验结果合理选用抗菌药物。     

嗜麦芽窄食单胞菌感染125株临床和耐药性分析

目的了解嗜麦芽窄食单胞菌感染的临床特点及对抗生素的耐药性。方法回顾性分析2006～2008年我院分离的嗜麦芽窄食单胞菌的耐药性以及所致感染病例的临床特点。结果125株嗜麦芽窄食单胞菌对多种抗生素耐药率较高,仅对甲氧苄啶/磺胺甲口恶唑、环丙沙星、替卡西林/克拉维酸、多黏菌素E耐药率较低,分别为11%、29%、12%、23%。结论加强环境消毒和控制广谱抗生素应用可有效降低嗜麦芽窄食单胞菌引起的医院感染的发生,甲氧苄啶/磺胺甲口恶唑、环丙沙星、替卡西林/克拉维酸可作为抗感染治疗的一线用药。     

1999-2003年嗜麦芽寡养单胞菌耐药性分析

目的了解1999-2003年嗜麦芽寡养单胞菌对常用抗菌药物的耐药性,为临床治疗嗜麦芽寡养单胞菌感染提供参考.方法采用Kirby-Bauer琼脂扩散法及微量肉汤稀释法.结果嗜麦芽寡养单胞菌对碳青酶烯类、β-内酰胺酶抑制剂复合制剂、头孢菌素类、单环类和氨基糖苷类抗生素都显示高水平耐药并且呈上升趋势.复方新诺明、环丙沙星和左旋氧氟沙星对嗜麦芽寡养单胞菌的耐药率最低,2003年分别为25.0%、15.6%和16.0%.结论对于嗜麦芽寡养单胞菌感染的治疗,应该根据药敏试验足量、联合应用两种或两种以上的抗菌药物.     

嗜麦芽寡养单胞菌感染分布及耐药性研究

目的了 解我院嗜麦芽寡养单胞菌的临床分布,分析细菌的耐药谱,提高其诊治水平.方法 对经VITEK系统鉴定出162株嗜麦芽寡养单胞菌,进行自动化、纸片扩散法药敏试验,统计分析其感染分布及耐药性变化.结果 在所有临床分离的嗜麦芽寡养单胞菌标本中,以痰液为主（90.1%）,其次为创口分泌物和咽拭子;该菌对大多数抗菌药物耐药,复方新诺明、环丙沙星的耐药率较低,分别为20.4%和22.2%.结论 嗜麦芽寡养单胞菌是重症监护病房（ICU）常见的医院感染致病菌,痰标本的分离率最高;合理使用抗菌药物、减少侵袭性操作、加强耐药性监测,有利于预防及控制医院嗜麦芽寡养单胞菌感染.     

The indirect pathogenicity of Stenotrophomonas maltophilia

Stenotrophomonas maltophilia has at least two inducible β-lactamases, L1 and L2, which can hydrolyze almost all classes of β-lactam antimicrobial agents. This study was done to verify the indirect pathogenicity of S. maltophilia that could promote the growth of other β-lactam agent-susceptible bacteria in a mixed culture. We counted CFU of β-lactam agent-susceptible bacteria under the presence of imipenem or ceftazidime in a pure culture and mixed culture with S. maltophilia. Our results showed that β-lactamase leaking from S. maltophilia can encourage the growth of Serratia marcescens and Pseudomonas aeruginosa even if imipenem or ceftazidime was supplemented. This study discovered a blind spot in chemotherapy against an indirect pathogen such as S. maltophilia.     

Spread of Stenotrophomonas maltophilia colonization in a pediatric intensive care unit detected by monitoring tracheal bacterial carriage and molecular typing

In our pediatric intensive care unit in Tours (France), intubated and ventilated inpatients are systematically monitored for tracheal bacterial colonization twice a week. This led us to detect five patients colonized with Stenotrophomonas maltophilia over a 4-month period. Molecular typing of the isolates using random amplified polymorphism DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) confirmed that four of the five isolates were genetically related. The strict isolation of carriers and improvements in hygiene measures stopped the spread. This systematic strategy prevented pulmonary nosocomial infections or allowed their early detection. Moreover, it has made it possible to assess the efficiency of care practices continuously.     

淡豆豉炮制过程中产纤溶酶微生物的筛选和鉴定

目的 筛选和鉴定淡豆豉炮制过程中产纤溶酶的优势菌株。方法 按《中国药典》2020年版制备淡豆豉;采用酪蛋白平板法和纤维蛋白平板法分别对淡豆豉炮制不同时间点样本中产纤溶酶的微生物进行初筛和复筛;将产纤溶酶微生物分别接种在特定的液体培养基中培养,获得纯种发酵液,用纤维蛋白平板法测定发酵液的纤溶酶活力;应用16S rDNA和18S rDNA通用引物分别对产纤溶酶细菌和真菌进行PCR扩增、对扩增产物进行测序,测序结果通过NCBI同源性比对、MEGA 4.1软件构建系统发育树进行分子生物学鉴定。结果 筛选获得3种产纤溶酶细菌,分别为枯草芽孢杆菌Bacillus subtilis、嗜麦芽窄食单胞菌Stenotrophomonas maltophilia、微球菌Micrococcus。纤维蛋白平板法测定纯种发酵液纤溶酶活力的结果显示,嗜麦芽窄食单胞菌所产纤溶酶活力最高,达527.49 IU/mL。结论 淡豆豉炮制过程中存在高产纤溶酶的优势菌株,淡豆豉的溶栓作用值得进一步研究。为揭示淡豆豉炮制中纤溶酶形成机制奠定基础。