抗MRSA海绵真菌的分离及菌株W0707的鉴定

目的对采自海南、湛江海域的海绵样品进行真菌选择性分离,对其发酵液进行抗MRSA活性筛选,并对活性较好的菌株进行鉴定。方法以耐甲氧西林金黄色葡萄球菌MRSA3558为指示菌,利用KB法进行活性菌株筛选,通过对菌株的培养特征、形态特征、18S rDNA序列测定及其系统发育分析对菌株W0707进行鉴定。结果与结论添加青霉素和链霉素的海水马丁氏培养基具有很好的培养真菌选择性,共分离得到真菌133株,活性筛选得到阳性菌株4株,其中菌株W0707具有较强的抗MRSA活性,通过各种指标鉴定菌株W0707为土曲霉(Aspergillus terreus)。     

黄芩苷/黄芩素对耐甲氧西林金黄色葡萄球菌抗药性的逆转作用研究

目的:研究黄芩苷/黄芩素对耐甲氧西林金黄色葡萄球菌(MRSA)抗药性的逆转作用,并初步探索其逆转机制。方法:以平皿法测定黄芩苷/黄芩素与苯唑西林对MRSA的协同抗菌效力;以分光光度法测定黄芩苷/黄芩素协同苯唑西林对MRSA生长密度的抑制作用;以青霉素结合蛋白(PBP2a)胶乳凝集试剂盒检测黄芩苷/黄芩素对PBP2a生成的抑制效力。结果:黄芩苷/黄芩素联合苯唑西林对临床分离的MRSA有显著的协同抗菌作用,16μg·mL-1的黄芩素即可显著逆转MRSA对苯唑西林的高度耐药;黄芩苷/黄芩素对MRSA产生PBP2a有显著抑制作用。结论:黄芩苷/黄芩素可通过抑制MRSA产生PBP2a来逆转其对苯唑西林的高度耐药,这一现象从理论上为临床治疗MRSA感染提供了新的方法和思路。     

Multidrug-resistant organisms in patients from Ukraine in the Netherlands,March to August 2022

Since March 2022, there has been an emergence of multidrug-resistant organisms (MDRO) in the Netherlands in patients originating from Ukraine (58 patients, 75 isolates). For about half of these patients, recent hospitalisation in Ukraine was reported. Genomic surveillance revealed that the majority of the MDRO represent globally spread epidemic lineages and that 60% contain New Delhi metallo-β-lactamase (NDM) genes. Professionals should be aware of an increase in such MDRO associated with migration and medical evacuation of people from Ukraine.     

丹参生品及不同炮制品的体外抗菌活性研究

目的研究丹参不同炮制品(清炒、炒炭、米炒、酒炙和醋制丹参)的体外抗菌活性。方法采用纸片扩散法研究丹参不同炮制品对金黄色葡萄球菌(SA)、耐甲氧西林的金黄色葡萄球菌(MRSA)和β-内酰胺酶阳性金黄色葡萄球菌(ESBLs)的抑制活性。结果丹参生品及不同炮制品对SA和MRSA的抑制作用略强于ESBLs,对SA的抗菌效果最强;其中炒丹参的甲醇总提取物质量浓度在50 mg/mL对SA、MRSA、ESBLs的抑菌圈直径最大且相同;对相应样品的MIC值进行比较,显示各样品体外抗菌活性大小依次为:丹参生品及炮制品的甲醇提取物>石油醚和乙酸乙酯提取物>正丁醇提取物。结论本实验证明炒丹参和酒丹参的抗菌活性明显增强,而丹参炭的抗菌活性明显减弱,但仍具有一定的抗菌活性。     

Ceftaroline fosamil as first-line versus second-line treatment for acute bacterial skin and skin structure infections (ABSSSI) or community-acquired bacterial pneumonia (CABP)

The Clinical Assessment Program and Teflaro^® Utilization Registry (CAPTURE) is a multicenter registry study of acute bacterial skin and skin structure infection (ABSSSI) and community-acquired bacterial pneumonia (CABP) patients treated with ceftaroline fosamil in the US. Data for this analysis were collected between August 2011 and February 2013 at US study centres by randomly ordered chart review. Clinical success rates among ABSSSI patients were >81% when ceftaroline fosamil was used as first- or second-line therapy, including monotherapy and concurrent therapy. Among CABP patients, clinical success rates were >77% among first-line and second-line patients and patients who received first-line concurrent therapy or second line monotherapy or concurrent therapy. For CABP patients treated with ceftaroline fosamil as first-line monotherapy, the clinical success rate was 70%. Ceftaroline fosamil is an effective treatment option for patients with ABSSSI or CABP with similar clinical success rates when used as first-line or second-line treatment.     

Early Response Assessment to Guide Management of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections With Vancomycin Therapy

Background

A subset of vancomycin-treated patients with methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) developed persistent positive blood cultures. Treatment eventually failed.

Methods

A retrospective study was conducted to determine whether early response on day 3 after initiation of vancomycin therapy for MRSA BSI was associated with reduced rates of persistent bacteremia, end-of-treatment failure, and infection-related mortality. Patients’ medical charts were reviewed. Susceptibility testing and molecular characterization of bacterial isolates were performed.

Results

In this elderly cohort (n = 111; median age 70 years, interquartile range: 57–80 years), early response was observed in 62% of patients and was significantly (P < 0.0001) associated with lower rates of end-of-treatment failure (19% vs 57%) and infection-related death (1% vs 29%), but not with persistent bacteremia (17% vs 29%, P = 0.23). Nearly half (46%; 46 of 100 patients) remained on vancomycin therapy for the entire treatment course; those who continued despite lack of early response had a trend toward a higher risk of death than those who were switched to alternative therapy (38% vs 10%, P = NS). Most (68%) isolates had vancomycin MIC of >1 µg/mL, whereas 10% showed heterogeneous glycopeptide-intermediate Staph aureus (hGISA) phenotype. Nearly half (47%) were typed with staphylococcal cassette chromosome mec IV or V. In a multivariate logistic regression model, lack of response at day 3 was the strongest predictor for end-of-treatment failure, after adjustment for confounders such as age, Acute Physiology And Chronic Health Evaluation II score, intensive care unit admission, vancomycin MIC >1 µg/mL, unbound trough concentration <4 to 5× MIC, and continued vancomycin therapy without change.

Conclusions

Early response assessment after initiation of vancomycin therapy appeared to be useful for considering further diagnostic workup or a switch to alternative therapy to affect a positive outcome in patients with MRSA BSI.     

Coincidental outbreak of methicillin-resistant Staphylococcus aureus in a hematopoietic stem cell transplantation unit

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens among hospital-acquired infections, and immunocompromised patients are highly susceptive to infection. The molecular typing of isolated strains is a common method for tracing an outbreak of MRSA, but experience with this approach is still limited in the hematopoietic stem cell transplantation (HSCT) ward. METHODS: We experienced 6 cases of MRSA infection/colonization in our 26-bed HSCT ward during a 4-week period. This unusual outbreak strongly suggested that the same MRSA strain was involved despite strict isolation and aseptic patient care. Clarification of the transmission pattern was critical, and we applied pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) assays for evaluation. RESULTS AND CONCLUSION: In four of the six cases, the pattern of bands examined by PFGE and AFLP analyses supported the idea that direct person-to-person transmission was very unlikely and the outbreak was coincidental. This experience highlights the clinical value of molecular typing methods for the clinical epidemiological assessment of MRSA outbreak.     

Antimicrobial susceptibility patterns of Staphylococcus aureus in Poland obtained by the National Quality Assurance Programme

As part of the Polish external quality assurance scheme, clinical laboratories were asked to send five consecutive isolates of Staphylococcus aureus and the corresponding susceptibility results to the national Centre of Quality Control in Microbiology. Of 1376 isolates submitted as S. aureus from 276 medical centres, 13 (< 1%) had been misidentified by local laboratories. Of 181 (13.5%) methicillin-resistant S. aureus (MRSA) isolates, most were identified correctly (c. 98% of laboratories). Although all MRSA isolates were fully susceptible to vancomycin, teicoplanin and linezolid, they were usually multiresistant; almost 23% were resistant to seven antimicrobial agents. Most (> 90%) MSSA isolates were susceptible to the tested antibiotics, except penicillin (21% susceptible) and tetracycline (62.4% susceptible). In addition to evaluating the proficiency of testing by local laboratories, the study yielded valuable information regarding the susceptibility patterns of S. aureus isolates in Poland.