Combination Therapy in Systemic Mycosis

Summary

One hundred eighty-four sputum specimens from the same number of patients with lower respiratory tract infections were examined to determine the bacterial count and the relationship between the microorganisms isolated and the presumptive pathology. The sputa were subdivided into three groups; “high probability”, “low probability”, and “contaminated sputa”, following the criteria of the microscopic readings: sputum with more than 25 white cells and low numbers of squamous epithelial cells represents true lower respiratory tract infections (high probability); those with fewer than 25 white cells represent non-bacterial infections or non-infected sputa (low probability) while sputa with more than 25 squamous cells per field represent contaminated specimens (contaminated sputa).

Statistical analysis was carried out to correlate these data. Haemophilus influenzae, Haemophilus parainfluenzae, Streptococcus pneumoniae, and Streptococcus pyogenes showed significant differences in the three groups considered.     

耐亚胺培南铜绿假单胞菌耐药特征及其耐药机制的研究

目的分析临床分离耐亚胺培南铜绿假单胞菌对常用抗菌药物的耐药特征及其对亚胺培南耐药机制。方法应用BD Phoenix100全自动微生物分析仪进行细菌鉴定和药物敏感试验,头孢哌酮/舒巴坦采用K-B法;应用聚合酶链反应（PCR）方法检测碳青酶烯酶相关基因（IMP、VIM、GIM、SPM、OXA、GES）、膜微孔蛋白基因oprD2,采用Etest试验观察氰氯苯腙（CCCP）对亚胺培南最低抑菌浓度（MIC）的影响,以研究细胞内主动外排机制。结果耐亚胺培南铜绿假单胞菌除对阿米卡星100%敏感外,对哌拉西林、哌拉西林/他唑巴坦敏感率为48.0%~54.0%,对三代、四代头孢菌素、氨曲南、喹诺酮类等抗菌药物抗菌活性差,敏感率为3.0%~29.0%;对美罗培南29.0%敏感,对氨苄西林/舒巴坦、氯霉素、四环素、复方新诺明全部耐药;检测到IMP阳性率17.6%,oprD2阳性率2.9%,其余耐药基因未检测到;当CCCP存在时,亚胺培南的MIC值下降4个浓度梯度,提示存在主动外排机制的菌株占11.8%。结论耐亚胺培南铜绿假单胞菌除阿米卡星外,对其他常用抗菌药物耐药严重;产IMP型金属β-内酰胺酶、细胞内主动外排机制以及膜微孔蛋白基因oprD2缺失,是铜绿假单胞菌对亚胺培南耐药的原因,但膜微孔蛋白基因oprD2缺失,不是铜绿假单胞对亚胺培南耐药的主要机制。     

Prevalence and molecular characterization of Enterobacteriaceae producing NDM-1 carbapenemase at a military hospital in Pakistan and evaluation of two chromogenic media

The aim of this study was to assess the frequency and genotypic diversity of carbapenemase-producing Enterobacteriaceae (CPE) in stool samples from patients attending a military hospital in Pakistan. Further aims included the identification of factors that might predispose to faecal carriage and evaluation of 2 chromogenic culture media: Brilliance CRE and chromID CARBA. Of 175 patients, 32 (18.3%) had faecal carriage of CPE and all produced NDM-1 carbapenemase. All of these 32 patients were detected using chromID CARBA compared with 20 patients (62.5%) detected using Brilliance CRE (P = 0.0015). Duration of hospitalization and treatment with co-amoxyclav were statistically associated with a higher likelihood of carriage of CPE (P ≤ 0.05). The majority of NDM-1–producing Enterobacteriaceae co-produced CTX-M-1 group extended spectrum β-lactamase, and one third produced armA-type methylase. NDM-1 carbapenemase was most commonly found amongst commensal types of Escherichia coli, especially phylogenetic group B1.     

Clinical laboratory detection of carbapenem-resistant and carbapenemase-producing Enterobacteriaceae

Introduction: Carbapenemases, enzymes that hydrolyze carbapenem-class antimicrobials, pose serious clinical and diagnostic challenges, including their recent rapid spread among members of the Enterobacteriaceae, a family with no inherent carbapenem resistance. Currently there is no one-size-fits-all method for detecting carbapenem-resistant Enterobacteriaceae (CRE) in the laboratory, nor how to differentiate carbapenemase-producers (CP) from isolates that are carbapenem-resistant via other or combined mechanisms.

Areas covered: This article reviews definitions for CRE and CP-CRE, and discusses current phenotypic and molecular methods available to the clinical laboratory for the detection of both CP and non-CP CRE.

Expert commentary: Routine evaluation of carbapenem resistance mechanism by the routine clinical laboratory are not necessary for patient care, as clinical breakpoints best predict response. However, evaluation for carbapenemase is integral to infection control efforts, and laboratories should have the capacity to do such testing, either in house or by submitting isolates to a reference laboratory.     

产Ⅰ型新德里金属β-内酰胺酶细菌的实验室检测方法

2010年8月以来,产Ⅰ型新德里金属β-内酰胺酶(NDM-1)细菌引起广泛关注。本文就产NDM-1细菌的实验室表型筛查、表型确证试验、基因确证检测等检测方法等做一综述,以期为实验室开展产NDM-1细菌的检测提供方法依据。     

Characteristics of KPC-2–producing Klebsiella pneumoniae (ST258) clinical isolates from outbreaks in 2 Mexican medical centers

The KPC-producing Klebsiella pneumoniae sequence type 258 (ST258) is an important pathogen widely spread in nosocomial infections. In this study, we identified the KPC-2–producing K. pneumoniae clinical isolates of 2 unrelated outbreaks that corresponded to pandemic strain ST258. The isolates showed high resistance to cephalosporins, carbapenems, quinolones, and colistin. The KPC-2–producing K. pneumoniae isolates were compared to the previously studied KPC-3–producing K. pneumoniae isolates from an outbreak in Mexico; they showed an unrelated pulsed-field gel electrophoresis fingerprinting pattern and a different plasmid profile. The KPC-2 carbapenemase gene was identified in two 230- and 270-kb non-conjugative plasmids; however, 1 isolate transferred the KPC-2 gene onto an 80-kb plasmid. These findings endorse the need of carrying out a continuous molecular epidemiological surveillance of carbapenem-resistant isolates in hospitals in Mexico.     

Interventional strategies and current clinical experience with carbapenemase-producing Gram-negative bacteria

The wide dissemination of carbapenemase-producing Gram-negatives (CPGNs), including enterobacterial species and non-fermenters, has caused a public health crisis of global dimensions. These organisms cause serious infections in hospitalized patients, and are associated with increased mortality. Cross-transmission is common, and outbreaks may occur in healthcare facilities where the infection control practices are inadequate. CPGNs exhibit extensive drug-resistant phenotypes, complicate therapy, and limit treatment options. Systematic data on therapy are limited. However, regimens combining two or more active agents seem to be more efficacious than monotherapy in carbapenemase-producing Klebsiella pneumoniae infections. Strict infection control measures, including active surveillance for timely detection of colonized patients, separation of carriers from non-carriers, and contact precautions, are of utmost importance, and may be the only effective way of preventing the introduction and transmission of these bacteria in healthcare settings.     

Comparison of matrix-assisted laser desorption ionization–time-of-flight mass spectrometry assay with conventional methods for detection of IMP-6, VIM-2, NDM-1, SIM-1, KPC-1, OXA-23, and OXA-51 carbapenemase-producing Acinetobacter spp., Pseudomonas aeruginosa, and Klebsiella pneumoniae

Matrix-assisted laser desorption ionization–time-of-flight mass spectrometry assay was able to detect carbapenemase producers, including SIM-1 or OXA-51, within 4 hours using 20 μL of 0.5 g/L ertapenem solution as a substrate. This assay is more rapid and accurate than the modified Hodge test and 3-dimensional extract bioassay. Hence, it can be used an alternative test to identify carbapenemase-mediated carbapenem resistance in Gram-negative bacteria.     

耐亚胺培南鲍曼不动杆菌碳青霉烯酶基因分析

目的研究我院耐亚胺培南鲍曼不动杆菌（IRAB）的耐药性与碳青霉烯酶基因型。方法收集我院耐亚胺培南鲍曼不动杆菌35株,K—B法和E—test法测定对常用抗茵药物的敏感性,采用改良Hodge试验和乙二胺四乙酸（EDTA）协同试验检测耐亚胺培南不动杆菌产碳青霉烯酶和金属β-内酰胺酶情况,聚合酶链反应（PcR）检测其碳青霉烯酶基因OXA-23、OXA-24、OXA-58、IMP、VIM。结果35株耐亚胺培南鲍曼不动杆菌对β-内酰胺类、部分氨基糖苷类、喹诺酮类及磺胺类抗菌药物均有很高耐药率（〉70％）,仅对阿米卡星、头孢哌酮／舒巴坦和多粘菌素B有较高的敏感性（〉70％）,35株耐亚胺培南鲍曼不动杆菌均产碳青霉烯酶,未检测到金属β-内酰胺酶,全部检测到OXA-23型基因,未检测到OXA-24、OXA-58、IMP、VIM型基因。结论耐亚胺培南鲍曼不动杆菌耐药相当严重;产OXA-23型碳青霉烯酶是我院鲍曼不动杆菌对亚胺培南耐药的主要原因。