The relationship between nasal and conjunctival cultures of antimicrobial-resistant isolates of methicillin-resistant Staphylococcus aureus

PurposeNasal screening is performed to avoid the complications of postoperative surgical site infections (SSI), especially those due to antimicrobial-resistant species such as methicillin-resistant Staphylococcus aureus (MRSA). This study examined the relationship between bacterial isolates from the conjunctiva and the nasal cavity.MethodsAll patients were diagnosed with ocular surface infections, and the organisms in the conjunctiva and the nasal cavity were isolated. We investigated the relationship of the following antimicrobial-resistant bacteria between the conjunctiva and the nose: MRSA, methicillin-resistant CNS (MRCNS), levofloxacin-resistant (LVFX-R) Corynebacterium spp. Data were analyzed using Fisher’s exact test, and the odds ratio was examined.ResultsThis study included 188 eyes of 188 subjects (87 males and 101 females; mean age 58.5 years, range 11–97 years). MRSA (4 eyes), MRCNS (29 eyes), and LVFX-R Corynebacterium spp. (41 eyes) were identified from the conjunctiva, and MRSA (6 eyes), MRCNS (38 eyes), and LVFX-R Corynebacterium spp. (41 eyes) were identified from the nasal cavity. There was a significant relationship detected between the conjunctiva and the nose for MRSA, MRCNS, and LVFX-R Corynebacterium spp. MRSA displayed high sensitivity (0.750, 95% confidence interval [CI]; 0.301 to 0.987) and specificity (0.984, 95% CI; 0.953 to 0.996) in nasal cavity cultures, and the odds ratio was 181.00 times (95% CI; 18.41 to 2320).ConclusionThis study showed a significant relationship between conjunctival and nasal cultures of MRSA, MRCNS, and LVFX-R Corynebacterium spp., suggesting that nasal cavity culture is a potentially useful screening method for detecting resistant bacteria, especially MRSA, in the conjunctiva.     

金黄色葡萄球菌异质性耐药机制及实验室检测技术

 异质性耐药是一种特殊的细菌耐药类型，常表现为同一克隆来源的不同细菌亚群对某种抗菌药物表现出不一致的耐药特征，大多数亚群对某种抗菌药物敏感，而少部分亚群对其耐药或高度耐药。异质性耐药分离株常会导致特定抗菌药物抗感染治疗失败。针对异质性耐药菌较为深入的研究主要集中于革兰阴性菌，革兰阳性球菌的相关报道较少。近年有研究报道万古霉素、利奈唑胺、苯唑西林等多种类型抗菌药物异质性耐药金黄色葡萄球菌分离株出现，但其实际临床意义尚待进一步评估。此文对金黄色葡萄球菌异质性耐药机制和检测技术最新进展进行综述，为细菌异质性耐药机制研究和新型检测技术研发提供新的思路。     

A new aspect of in vitro antimicrobial leukocyte- and platelet-rich plasma activity based on flow cytometry assessment

The current literature suggests that the antibacterial effect of leukocyte- and platelet-rich plasma (L-PRP) is directly related to platelet and leukocyte concentrations. The aim of this study was twofold: first, to evaluate the antimicrobial effect of L-PRP against selected bacterial strains in vitro, and second, to correlate this effect with leukocyte and platelet content in the final concentration. Blood was collected from 20 healthy males, and L-PRP, acellular plasma (AP), and autologous thrombin were consecutively prepared. Flow cytometry analysis of the blood, L-PRP, and AP was performed. The L-PRP gel, liquid L-PRP, and thrombin samples were tested in vitro for their antibacterial properties against seven selected bacterial strains using the Kirby–Bauer disk-diffusion method. There was notable antimicrobial activity against selected bacterial strains. No statistically significant correlations between antimicrobial activities and the platelet concentration in L-PRP were observed. Statistically significant positive correlations between selected leukocyte subtypes and antimicrobial activity were noted. A negative correlation was found between elevated monocyte count and antimicrobial activity of L-PRP against one bacterial strain studied. L-PRP possesses antimicrobial activity and can be potentially useful in the fight against certain postoperative infections. The bactericidal effect of L-PRP is caused by leukocytes, and there exists a relationship among selected leukocyte subtypes and L-PRP antimicrobial activity.     

反复粪便培养金黄色葡萄球菌阳性老年患者口服万古霉素效果评价

目的 通过探讨肠道非急性感染期反复粪便培养金黄色葡萄球菌阳性的老年患者口服万古霉素的效果，为此类患者提供一种潜在的治疗方案。方法 前瞻性分析吉林大学第一医院干部病房2015 年9 月～2018 年12 月收治的186 例肠道非急性感染期反复粪便培养金黄色葡萄球菌阳性的老年患者。根据是否口服万古霉素治疗分为万古组和对照组。收集两组患者的一般临床资料，比较两组患者试验前后万古霉素血药浓度、血常规、降钙素原（PCT）、C 反应蛋白（CRP），试验期间粪便培养结果、体温、抗生素使用情况。结果 试验治疗期间，万古组便培养转阴率高于对照组，差异有统计学意义（P＜0.05）；万古组发热率（29.75%）低于对照组的34.77%，差异有高度统计学意义（P＜0.01）；万古组抗生素使用率（4.49%）低于对照组的19.23%，差异有高度统计学意义（P＜0.01）。试验前两组白细胞、中性粒细胞计数、中性粒细胞比例、PCT、CRP 比较，差异无统计学意义（P＞0.05）；试验后万古组白细胞、中性粒细胞计数、中性粒细胞比例、CRP 低于对照组，差异有高度统计学意义（P＜0.01）。试验后万古组白细胞、中性粒细胞计数、中性粒细胞比例、CRP 低于试验前，差异有高度统计学意义（P＜0.01）。结论 口服万古霉素可能提高肠道非急性感染期反复粪便培养金黄色葡萄球菌阳性的老年患者粪便转阴率，减少发热及抗生素的应用，降低炎症细胞水平，可能是此类患者一种潜在的临床治疗方案。     

Therapeutics and delivery vehicles for local treatment of osteomyelitis

Osteomyelitis, or the infection of the bone, presents a major complication in orthopedics and may lead to prolonged hospital visits, implant failure, and in more extreme cases, amputation of affected limbs. Typical treatment for this disease involves surgical debridement followed by long-term, systemic antibiotic administration, which contributes to the development of antibiotic-resistant bacteria and has limited ability to eradicate challenging biofilm-forming pathogens including Staphylococcus aureus—the most common cause of osteomyelitis. Local delivery of high doses of antibiotics via traditional bone cement can reduce systemic side effects of an antibiotic. Nonetheless, growing concerns over burst release (then subtherapeutic dose) of antibiotics, along with microbial colonization of the nondegradable cement biomaterial, further exacerbate antibiotic resistance and highlight the need to engineer alternative antimicrobial therapeutics and local delivery vehicles with increased efficacy against, in particular, biofilm-forming, antibiotic-resistant bacteria. Furthermore, limited guidance exists regarding both standardized formulation protocols and validated assays to predict efficacy of a therapeutic against multiple strains of bacteria. Ideally, antimicrobial strategies would be highly specific while exhibiting a broad spectrum of bactericidal activity. With a focus on S. aureus infection, this review addresses the efficacy of novel therapeutics and local delivery vehicles, as alternatives to the traditional antibiotic regimens. The aim of this review is to discuss these components with regards to long bone osteomyelitis and to encourage positive directions for future research efforts.     

Effect of antimicrobial peptides HNP-1 and hBD-1 on Staphylococcus aureus strains in vitro and in vivo

The aims of this study were: (i) To investigate the activity of recombinant AMPs HNP-1 and hBD-1 in combination with cefotaxime against Staphylococcus aureus strains (MSSA and MRSA) in vitro using checkerboard method; (ii) To investigate the activity of HNP-1 and hBD-1 encapsulated in silicon nanoparticles (niosomes) in the treatment of MRSA-infected wound in rats. For this S. aureus strains (MSSA and MRSA) were isolated from patients with diabetic foot infection. Cefotaxime, recombinant HNP-1 and hBD-1 (in all possible combinations with each other) were used for testing by the checkerboard method. Two niosomal topical gels with HNP-1/hBD-1 were prepared to treat MRSA-infected wounds in rats. Gels were administered once a day, the control group–without treatment. Wound healing rate was calculated on the 4th, 9th and 16th days of the experiment and compared using one-way ANOVA with Bonferroni correction. MIC of HNP-1 for MSSA and MRSA was the same–1 mg/L. MIC of hBD-1 for MSSA and MRSA was also the same–0.5 mg/L. Topical gels with niosomal HNP-1 (or hBD-1) showed a significantly faster wound healing in comparison with the control. The data obtained open up prospects for use of AMPs encapsulated in silica nanoparticles for the development of new antibiotics.     

Aortitis and periaortitis: The puzzling spectrum of inflammatory aortic diseases

Aortitis and periaortitis are inflammatory diseases of the aorta and its main branches; they differ in the extension of inflammation, which is confined to the aortic wall in aortitis, and spreads to the periaortic space in periaortitis. Aortitis is classified as non-infectious or infectious. Non-infectious aortitis represents a common feature of large-vessel vasculitides but can also be isolated or associated with other rheumatologic conditions. Periaortitis can be idiopathic or secondary to a wide array of etiologies such as drugs, infections, malignancies, and other proliferative diseases. Notably, both aortitis and periaortitis may arise in the context of IgG4-related disease, a recently characterised fibro-inflammatory systemic disease. Prompt recognition, correct diagnosis and appropriate treatment are essential in order to avoid life-threatening complications.