Antimicrobial Resistance in Gram-Negative Hospital Isolates: Results of the Turkish HITIT-2 Surveillance Study of 2007

Abstract

Resistance rates to amikacin, ciprofloxacin, ceftazidime, cefepime, imipenem, cefoperazone/sulbactam and piperacillin/tazobactam in Escherichia coli (n= 438)Klebsiella pneumoniae (n= 444)Pseudomonas aeruginosa (n= 210) and Acinetobacterbaumanni (n=200) were determined with e-test in a multicenter surveillance study (HITIT-2) in 2007. ESBL production in Escherichia coli and K. pneumoniae was investigated following the CLSI guidelines. Overall 42.0% of E.coli and 41.4% of K. pneumoniae were ESBL producers. In E. coli, resistance to imipenem was not observed, resistance to ciprofloxacin and amikacin was 58.0% and 5.5% respectively. In K. pneumoniae resistance to imipenem, ciprofloxacin and amikacin was 3.1%, 17.8% 12.4% respectively. In P. aeruginosa the lowest rate of resistance was observed with piperacillin/tazobactam (18.1%). A. baumanni isolates were highly resistant to all the antimicrobial agents, the lowest level of resistance was observed against cefoperazone/sulbactam (52.0%) followed by imipenem (55.5%). This study showed that resistance rates to antimicrobials are high in nosocomial isolates and show variations among the centers.     

Comparison of ß-lactam plus aminoglycoside versus ß-lactam plus fluoroquinolone empirical therapy in serious nosocomial infections due to Gram-negative bacilli

We sought to compare clinical cure on day 7 and a 28-day all-cause mortality in patients who received an anti-pseudomonal ß-lactam with a fluoroquinolone or an aminoglycoside for treatment of nosocomial bacteremia or pneumonia due to Gram-negative bacilli while in the ICU. This retrospective cohort study was conducted in critically ill patients at an academic medical centre from January 2005 to August 2011. A total of 129 patients (83 receiving aminoglycoside and 46 receiving fluoroquinolone combinations) were included. Seven-day clinical cure rates were 74% and 72% for fluoroquinolone and aminoglycoside groups, respectively (p = 0.84). There was no significant difference in the odds of clinical cure with a fluoroquinolone as compared to an aminoglycoside combination (adjusted odds ratio 2.4, 95% confidence interval [CI] 0.7–9.0). There was no significant difference in 28-day mortality in patients who received a fluoroquinolone or an aminoglycoside combination (22% vs. 18%, adjusted hazard ratio 0.82, 95% CI 0.29–2.28).     

Therapies for multidrug resistant and extensively drug-resistant non-fermenting gram-negative bacteria causing nosocomial infections: a perilous journey toward ‘molecularly targeted’ therapy

Introduction: Non-fermenting Gram-negative bacilli are at the center of the antimicrobial resistance epidemic. Acinetobacter baumannii and Pseudomonas aeruginosa are both designated with a threat level to human health of ‘serious’ by the Centers for Disease Control and Prevention. Two other major non-fermenting Gram-negative bacilli, Stenotrophomonas maltophilia and Burkholderia cepacia complex, while not as prevalent, have devastating effects on vulnerable populations, such as those with cystic fibrosis, as well as immunosuppressed or hospitalized patients.

Areas covered: In this review, we summarize the clinical impact, presentations, and mechanisms of resistance of these four major groups of non-fermenting Gram-negative bacilli. We also describe available and promising novel therapeutic options and strategies, particularly combination antibiotic strategies, with a focus on multidrug resistant variants.

Expert commentary: We finally advocate for a therapeutic approach that incorporates in vitro antibiotic susceptibility testing with molecular and genotypic characterization of mechanisms of resistance, as well as pharmacokinetics and pharmacodynamics (PK/PD) parameters. The goal is to begin to formulate a precision medicine approach to antimicrobial therapy: a clinical-decision making model that integrates bacterial phenotype, genotype and patient’s PK/PD to arrive at rationally-optimized combination antibiotic chemotherapy regimens tailored to individual clinical scenarios.     

清热合剂对上呼吸道感染常见致病菌的体外抑菌试验

目的观察清热合剂对上呼吸道感染常见致病菌的体外抑菌活性。方法上呼吸道感染常见致病菌163株中不产超广谱β-内酰胺酶(ESBLs)革兰阴性菌74株(大肠埃希菌33株,肺炎克雷伯菌24株,铜绿假单胞菌17株);产ESBLs革兰阴性菌10株(大肠埃希菌6株,肺炎克雷伯菌4株);革兰阳性菌79株[耐甲氧西林金黄色葡萄球菌(MRSA)11株、甲氧西林敏感金黄色葡萄球菌(MSSA)46株,肺炎链球菌22株]。采用琼脂稀释法对清热合剂进行定量抑菌试验,配制含有不同药物浓度的琼脂平板,在平板上接种待测菌株菌悬液,孵育后观察含药平板,记录最低抑菌浓度(MIC)。结果清热合剂对大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌等革兰阴性菌的MIC90分别为88、176、22 g/L,其对产ESBLs与不产ESBLs革兰阴性菌的抑菌效果一致;不同浓度药物对铜绿假单胞菌的累积抑菌率均最高。清热合剂对MSSA、MRSA和肺炎链球菌等革兰阳性菌的MIC90分别为11、11、22 g/L,MRSA的MIC90与MSSA相同,但MIC50略高于MSSA;不同浓度药物对MSSA和MRSA的累积抑菌率均高于肺炎链球菌,对MSSA与MRSA的累积抑菌率相近。结论清热合剂对上呼吸道感染常见的致病菌除肺炎克雷伯菌之外均有一定的抑菌作用,对革兰阳性菌的抑菌效果明显优于革兰阴性菌。     

Evaluating Epidemiology and Improving Surveillance of Infections Associated with Health Care,United States

The Healthcare-Associated Infections Community Interface (HAIC), launched in 2009, is the newest major activity of the Emerging Infections Program. The HAIC activity addresses population- and laboratory-based surveillance for Clostridium difficile infections, candidemia, and multidrug-resistant gram-negative bacilli. Other activities include special projects: the multistate Healthcare-Associated Infections and Antimicrobial Use Prevalence Survey and projects that evaluate new approaches for improving surveillance. The HAIC activity has provided information about the epidemiology and adverse health outcomes of health care–associated infections and antimicrobial drug use in the United States and informs efforts to improve patient safety through prevention of these infections.     

下呼吸道感染主要革兰阴性菌分布与耐药性分析

目的探讨医院下呼吸道感染主要革兰阴性菌的分布及其耐药性,为下呼吸道感染患者的治疗提供用药借鉴。方法选取2011年1月-2013年12月住院治疗的下呼吸道感染患者82例,采集所有患者合格痰标本,采用VITEK-2Compact全自动微生物分析系统对病原菌进行鉴定及药敏试验,使用WHONET5.4软件进行统计分析。结果 82例呼吸道感染患者痰液标本中共分离出革兰阴性菌105株,前4位依次为肺炎克雷伯菌、铜绿假单胞菌、大肠埃希菌、鲍氏不动杆菌,分别占20.00%、19.05%、17.14%、17.14%;肺炎克雷伯菌与大肠埃希菌对头孢唑林、头孢他啶、氨曲南、呋喃妥因的耐药率均<30.00%;对亚胺培南耐药率均<6.00%;肺炎克雷伯菌、铜绿假单胞菌、大肠埃希菌对氨苄西林、头孢替坦耐药率较高,均>80.00%。结论医院患者下呼吸道感染的主要革兰阴性菌以肺炎克雷伯菌、铜绿假单胞菌等为主,药敏差异较大,临床应根据药敏结果针对性选择用药,减少耐药菌株出现。     

Detection of the common resistance genes in Gram-negative bacteria using gene chip technology

Objective: To design a resistance gene detection chip that could, in parallel, detect common clinical drug resistance genes of Gram-negative bacteria. Materials and Methods: Seventy clinically significant Gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii) were collected. According to the known resistance gene sequences, we designed and synthesized primers and probes, which were used to prepare resistance gene detection chips, and finally we hybridized and scanned the gene detection chips. Results: The results between the gene chip and polymerase chain reaction (PCR) were compared. The rate was consistently 100% in the eight kinds of resistance genes tested (TEM, SHV, CTX-M, DHA, CIT, VIM, KPC, OXA-23). One strain of Pseudomonas aeruginosa had the IMP, but it was not found by gene chip. Conclusion: The design of Gram-negative bacteria-resistant gene detection chip had better application value.