Tubuloreticular Inclusions and Paired Cisternae Induced in Human Lymphocytes Cultured with Staphylococcus Aureus Cowan 1

Tubuloreticular inclusions (TRI) and paired cisternae (PC) were induced in lymphocytes of normal individuals after incubation with Staphylococcus aureus Cowan 1. TRI were initially detected in lymphoid cells on day 2 (48-h culture). The frequency of TRI-positive cell sections on day 5 increased about twofold over those on days 2–4. On day 7, TRI were predominantly seen in lymphoplasmacytoid cells or plasmacytoid cells, with an incidence of up to 18% of sections. The regions in these cells were most extensive and anastomosed with the cisternae of adjacent well-developed rough endoplasmic reticulum (RER). TRI formation appears not to be essential for mitogen-induced B-cell differentiation to plasmacytoid cells, because poke-weed mitogen (PWM) failed to induce TRI. The diverse expressions of TRI induction between these two mitogens may be due to a difference in B-cell activation mechanisms.

Paired cisternae were observed in a great majority of mitotic cells at various stages. These were encountered most frequently on day 4. PC were also seen in the PWM-stimulated culture. Our observations suggest that PC formation may be related to new formation of RER as well as to reconstruction of the nuclear envelope.     

Surface roughness enhances upward migration of bacteria on polymer fibers above liquid cultures

Monofilament polypropylene (PP) fibers, very similar to fibers that have been used as monofilament tailstrings of interuterinc contraceptive devices, were suspended vertically in bacterial liquid monocultures so that a portion of a fiber extended above the liquid surface. In some cases these highly oriented, cold drawn fibers were abraded prior to insertion in the cultures in order to produce surface roughness characterized by axial channels and protruding microfibrils that partially peeled from the fiber surface thereby forming the channels. Extent of migration on a fiber was assessed by aseptically cutting it into small segments, followed by culturing each segment on agar containing growth medium. Such assessment of the PP fibers after 48 h of incubation in the cultures revealed upward migration of Eschericia coli, Pseudomonas aeruginosa, and Staphylococcus aureus over significantly longer distances on the pre-roughened fibers than on those not so pre-treated. Mean measured distances of migration during 48 h were: for E. coli 2.7 ± 0.6 mm on roughened fibers (n = 16) and 0.4±0.7 mm on fibers not roughened (n = 17); for S. aureus 9.0±4.3 mm on roughened fibers (n = 13) and 0.2± 0.3 mm on fibers not roughened (n = 14); for P. aeruginosa 8.5± 3.7 mm on roughened fibers (n = 26) and 0.2± 0.5 mm on fibers not roughened (n = 5). Although no statistically significant (95% confidence level) difference could be discerned between the migration distances of S. aureus and P. aeruginosa, each of these species migrated a greater distance on the PP than did E. coli. The migrations observed are attributed predominantly to wicking of the liquid cultures upward in the axial grooves developed on the surface of the PP by the eruption and peeling of microfibrils from the surface. Surface tension of the growth medium was significantly lower than that of water and its contact angle on PP was less than 90 deg, thereby indicating a tendency to wet the PP. Bacterial growth in the medium further reduced its contact angle on PP, thereby indicating an even greater tendency to wet PP after such growth.     

The effectiveness of dalethyne dressings for reducing bacteria in diabetic foot ulcers

Objective: This study evaluates the effectiveness of a dalethyne dressing for decreasing bacteria in diabetic patients with infected foot ulcers. Methods: This study was conducted from March to September 2018 with a sample of 30 par ticipants from the outpatient Kitamura Wound Clinic in Pontianak City, Indonesia. A quasi-experimental non-equivalent pretest–posttest control group design was used for the study. Participants were divided into two groups: an intervention group (treated with a dalethyne dressing) and a control group (treated with a standard dressing). Two trained research assistants collected the data using the Wagner wound classification system and a bacteria counter. The assistants swabbed each wound surface with sterile cotton, and the swabs were used to conduct a bacteria culture and count. Results: The study population was 50％ female and 50％ male with no significant differences between each other in age, HbA1c, blood pressure, or ankle-brachial index (ABI; P > 0.05). Both groups had a significant reduction in the number of bacteria from the pretest to posttest (P < 0.05). Mann–Whitney analysis of posttest data indicated a significant difference in bacteria reduction between the control group (median = 2.25) and the intervention group (median = 7.6; P = 0.018). It was noted that Staphylococcus aureus was found in the control group at posttest, but not in the intervention group. Conclusions: This study provides evidence that a dalethyne dressing is effective for killing S. aureus in the infected foot ulcers of diabetic patients.     

不同管径二氧化钛纳米管的抗菌性能研究

目的:探讨不同管径二氧化钛纳米管的抗菌性能。方法:通过电化学阳极氧化法,在10、30和60 V三组电压下,于纯钛表面制备了3组二氧化钛纳米管NT10、NT30和NT60。扫描电镜观察试样的表面形貌,X射线衍射仪检测其晶体结构,接触角测试仪测量其接触角,原子力显微镜观察试样的表面形貌并比较表面粗糙度。将金黄色葡萄球菌和牙龈卟啉单胞菌接种到不同材料表面,扫描电镜观察菌落形态,活细菌平板计数活菌数。结果:3组二氧化钛纳米管的管径分别约为30 nm(NT10)、100 nm(NT30)和200 nm(NT60),X射线衍射结果显示3种二氧纳米管均出现了锐钛矿的衍射峰,接触角检测结果显示3种二氧化钛纳米管的接触角随着管径的增加而减小,原子力显微镜检测结果显示3组纳米管的粗糙度值均明显变小(其中NT30展示出最小的粗糙度值)。3种不同管径纳米管的表面活细菌数均明显减少,其中表面粘附金黄色葡萄球菌最少的是NT60,表面粘附牙龈卟啉单胞菌最少的是NT30。结论:纯钛表面纳米化制备二氧化钛纳米管后均不同程度地抑制了细菌的粘附。     

2016~2019年陕西省榆林市细菌耐药监测网成员单位金黄色葡萄球菌的临床分布与耐药性变迁

目的　分析 2016-2019年陕西省榆林市细菌耐药监测网成员单位金黄色葡萄球菌临床分布与耐药性变迁,为金黄色葡萄球菌感染合理用药提供依据。方法　收集 2016~2019年陕西省榆林市细菌耐药监测网成员单位（榆林市一院、榆林市二院、府谷县人民医院、神木市医院、榆林星元医院、定边县医院、靖边县医院、绥德县医院共 8家医院）常规分离、培养的 1 296株金黄色葡萄球菌的监测数据,所有检测按 CLSI2019规定的标准执行。结果　1 296株金黄色葡萄球菌（ SAU）从科室分布看,主要分布在外科（ 19.3%）、儿科（ 13.1%）、重症医学科（ 8.7%）和骨科（ 8.2%）;从标本类型分布看,主要分布在痰液（ 23.8%）、分泌物（ 22.7%）、脓液（ 13.7%）和伤口（ 11.9%）。在 1 296株 SAU中甲氧西林耐药金黄色葡萄球菌（ MRSA）占比为 20.2%;MRSA比甲氧西林敏感金黄色葡萄球菌（ MSSA）抗生素耐药率明显偏高,两组之间的差异有统计学意义（ P<0.01）;四年内对青霉素耐药率都在 93.3%以上;对红霉素耐药率都在 62.7%以上;对克林霉素耐药率都在 26.8%以上;对复方新诺明耐药率都在 25%以下,且有连续下降的趋势;对氯霉素、利福平、环丙沙星、莫西沙星和庆大霉素的耐药性都在 15%以下;对利奈唑胺、万古霉素、替考拉宁和呋喃妥因四类药物尚未产生耐药性。结论　利奈唑胺、万古霉素、替考拉宁及呋喃妥因均可作为 SAU感染的经验用药,除此外其他抗生素选用建议要参照药敏试验进行,以此来促进金黄色葡萄球菌感染的精准治疗并延缓耐药菌株的出现。     

Methicillin-resistant Staphylococcus aureus in children with cystic fibrosis: An eradication protocol

A retrospective 12-year study (May 1988-July 2000) was undertaken in children with cystic fibrosis (CF) to evaluate 1) the magnitude of methicillin-resistant Staphylococcus aureus (MRSA) in these children; 2) the clinical impact of MRSA on CF; and 3) the efficacy of an MRSA protocol aimed at the eradication of the carrier state. The study maneuver comprised of 1) surveillance cultures of throat/rectum to detect the MRSA carrier state; 2) life-long cephradine rather than flucloxacillin to lift selection pressure; 3) topical application of oral and nebulized vancomycin for 5 days to clear the carriage of MRSA; and 4) a strict antistaphylococcal hygiene program, including handwashing and device policy. Fifteen children with CF (11 boys, with median age 117 months) positive for MRSA were enrolled. The current prevalence of MRSA among children with CF in our hospital is 6.5%. Of 15 children identified, only 12 (18 episodes of MRSA colonization) were treated according to protocol. Median age of MRSA acquisition was 73 months (interquartile range, 43-134 months). In 7 patients (55%), MRSA was eradicated. Of a total of 18 MRSA episodes, the protocol was successful in 10 episodes. The mean period of MRSA-free status was 12 months (range, 6-36 months). Pulmonary function (measured by FEV(1)) was not affected (68% of predicted before treatment, and 68% of predicted after treatment). All children were oropharyngeal carriers of both MRSA and ceftazidime-resistant P. aeruginosa. We believe that an effort has to be made to limit MRSA in CF clinics for the following reasons: 1) MRSA carriage in any individual is an abnormal condition; 2) limitation of systemic vancomycin use is desirable; 3) MRSA carriage may be a contraindication for lung transplantation; and 4) epidemiologically, a CF unit with a substantial MRSA problem functions as a source of dissemination for other patients.