Emergence of Vancomycin-resistant Enterococci at a Teaching Hospital, Saudi Arabia

Background： Vancomycin-resistant enterococci （VRE） are a major and emerging hospital-acquired pathogen associated with high mortality, particularly among the critically ill and Intensive Care Units （ICUs） patients. This study aimed to determine the prevalence and demographic and clinical characteristics of VRE among patients admitted to a university hospital in Riyadh, Saudi Arabia. Methods： A study was conducted during the period from September 2014 to November 2015 at King Khalid University Hospital, a tertiary care hospital in Riyadh, Saudi Arabia, including in-patients with VRE infection. Data were collected using laboratory results and the medical records of admitted patients and were analyzed using SPSS version 19.0 statistical software. Results： In a one-year period, 231 enterococci were isolated from blood, urine, exudates, sputum, stool, and body fluid. There were 191 （82.7%） vancomycin-sensitive enterococci （VSE） and 40 （I 7.3%） isolates were VRE. The Enterococcus species included E.faecalis 168 （72.7%）, E.faecium, 53 （22.8%） E. gallinarum 5 （2.2%）, and E. avium 5 （2.2%）. VRE were more significant from blood specimens （P 〈 0.000 I） while VSE were significantly more predominant from urine specimens （P 〈 0.0001）. VRE were more commonly isolated from patients in ICUs and oncology unit （P = 0.0151 and P 〈 0.001, respectively） while VSE were more predominant in the medical and surgical areas （P = 0.0178 and P = 0.0178, respectively）. Conclusions： This study highlights the high prevalence of VRE in the hospital and the association of enterococcal infections with high-risk areas and oncology units, which warrant more studies looking for better management of these infections.

Endocarditis Due to Vancomycin-Resistant <i>Enterococccus gallinarum</i>in a Patient with End-Stage Renal Failure: A Case Report

The first described vancomycin resistant enterococci (VRE) was about twenty years ago. Recently VRE have been reported by many clinics. However endocarditis due to VRE is still a rare entity and there are only a few cases reported in the literature. We are reporting a 59-year-old male patient with chronic renal failure who was on hemodialysis. He presented with a sudden onset of fever, tachycardia and respiratory distress. The performed echocardiography revealed vegetations on the mitral and aortic valves. As he was diagnosed to have infective endocarditis the patient was put on ampicillin and gentamicin therapy. He underwent an emergent mitral and aortic valve surgery due to ensued heart failure. While he was still on ampicillin and gentamicin therapy, E. gallinarum, which was resistant to vancomycin (MIC = 8 mg/L), was isolated from the surgical valve specimens and hence his antibiotic regime was switched to teicoplanin (MIC < 0.5 mg/L). 28 days after teicoplanin therapy the patient was discharged with free of symptoms and any complication. This patient is presented as an example for an endocarditis with an unusual type of enterococci.

Inhibition mechanisms of secretome proteins from Paenibacillus polymyxa Kp10 and Lactococcus lactis Gh1 against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus

Objective:To determine the inhibition mechanisms of secretome protein extracted from Paenibacillus polymyxa Kp10(Kp10)and Lactococcus lactis Gh1(Gh1)against methicillin-resistant Staphylococcus aureus(MRSA)and vancomycin-resistant Enterococcus(VRE).Methods:The sensitivity and viability of MRSA and VRE treated with secretome proteins of Kp10 and Gh1 were determined using minimal inhibitory concentration,minimum bactericidal concentration,and time-to-kill assays.The morphological changes were observed using scanning electron microscopy and transmission electron microscopy.To elucidate the antimicrobial mechanism of secretome protein of Kp10 and Gh1 against MRSA and VRE,2D gel proteomic analysis using liquid chromatography-mass spectrometry was run by comparing upregulated and downregulated proteins,and the proton motive force study including the efflux of ATP,pH gradient,and the membrane potential study were conducted.Results:MRSA and VRE were sensitive to Kp10 and Gh1 secretome protein extracts and displayed apparent morphological and internal composition changes.Several proteins associated with cellular component functions were either downregulated or upregulated in treated MRSA and VRE by changing the membrane potential gradient.Conclusions:Kp10 and Gh1 secretome proteins reduce the growth of VRE and MRSA by damaging the cell membrane.Cell division,cell wall biosynthesis,and protein synthesis are involved in the inhibition mechanism.

Fecal Enterococci Levels in Selected Tributaries of the Pampanga River Basin, Philippines, and Their Relation to Land Use

This study aims to generate data which can be used as a potential starting point for the updating of the Philippine Water Quality Criteria and the determination of the true impact of land use to the fecal contamination of the Pampanga River Basin (PRB), the largest subwatershed of Manila Bay. Levels of fecal indicator bacteria (FIB) were determined in the selected tributaries of the PRB, representing three land use categories, namely, the forest/woodland (control), agricultural and residential lands. FIB were quantified in order to investigate the potential contribution of the selected areas in the fecal contamination of the PRB. The study was conducted in 2021 covering March, May, June, July, and September to represent the dry (March and May) and wet (June, July, and September) seasons. Counts of FIB, namely thermotolerant coliform, E. coli, and enterococci were qualitatively correlated with the results of the ocular survey and key informant interview based on known fecal contributors and their relevant rainfall data. FIB counts of water bodies in the selected agricultural and residential land use categories had Geometric Mean (GM) counts that are statistically greater than those of bodies of water near the representative forest/woodland (control), and exceeded the acceptable GM limits for all FIB, regardless of the season. Notably, the GM values recorded for the waters near the selected forest/woodland (control) passed the water quality criteria for all measured FIB parameters for both seasons. Furthermore, enterococci levels in the control site were statistically lower during the wet season. These initial findings suggest that agricultural and residential land use categories could be major contributors to the unacceptable water quality of tributaries of the Pampanga River Basin. The prevalence of thermotolerant coliforms and E. coli was noted regardless of rainfall and land use, indicating these FIB may not be adequate as water quality indicators. With their ability to survive and persist in fecally contaminated sediments in water bodies and in nutrient-poor environments, enterococci could be more definitive indicators of fecal contamination and microbiological quality of environmental waters.

氯己定擦浴预防ICU病人多重耐药菌感染效果的Meta分析

目的:系统评价氯己定全身擦浴对重症监护室(ICU)病人多重耐药菌感染的预防效果。方法:检索the Cochrane Library、PubMed、Web of Science、EMbase、中国知网、万方数据库、维普数据库、中国生物医学文献数据库中关于氯己定全身擦浴预防ICU病人多重耐药菌感染效果的中英文文献。由2名研究者根据纳入与排除标准独立筛选文献、质量评价及提取资料,采用Stata 16.0软件进行Meta分析。结果:最终纳入11项研究共23090例病人。Meta分析结果显示,与常规温水或肥皂水擦浴比较,氯己定能降低ICU病人多重耐药菌感染(OR=0.770,P<0.001)。其中氯己定全身擦浴能降低耐万古霉素肠球菌(VRE)(OR=0.664,P=0.004)及耐碳青霉烯类铜绿假单胞菌(CRPA)(OR=0.442,P=0.034)的感染发生风险,但不能降低耐甲氧西林金黄色葡萄球菌(MRSA)(OR=0.852,P=0.193)及耐碳青霉烯类鲍曼不动杆菌(CRAB)的感染发生风险(OR=0.888,P=0.537)。结论:现有证据显示,氯己定全身擦浴能降低ICU病人多重耐药菌感染,但仅对部分耐药菌有效。

Influence of enterococci on human sperm membrane in vitro

Aim： To study the influence of enterococci on human sperm membrane in vitro. Methods： Ejaculated human sperm were artificially infected with β-hemolytic or non-β-hemolytic enterococci at the bacteria： sperm ratio of 50：1 at 37℃. Sperm membrane integrity was examined after incubation for 1, 3 and 5 h by hypoosmotic swelling （HOS） test and electron microscopy. Results： Sperm infected with β-hemolytic enterococci had lower HOS scores compared with non-β-hemolytic strains or uninfected control （P 〈 0.01）. The HOS test scores of sperm infected with β-hemolytic enterococci increased in the presence of phosphatidylcholine, an inhibitor of hemolysin. Non-β-hemolytic strains showed no significant difference in swelling rate, compared with the control group （P 〉 0.05）. It was shown by electron microscopy that β-hemolytic enterococci caused significant rupture of human sperm membrane. Conclusion： β-hemolytic enterococci caused human sperm membrane injury, and might be mediated by the hemolysin of enterococci.

Survival of Epidemic, Clinical, Faecal and Recreational Beach Enterococci Strains with Putative Virulence Genes in Marine and Fresh Waters

Culturable faecal coliform, epidemic, clinical, faecal and recreational beach enterococci strains possessing putative virulence genes were enumerated over the course of 5 weeks to comparatively assess their persistence in tropical marine and fresh waters. For the clinical and epidemic strains tested, it took 2.38 ± 0.45 days for a 1-log reduction (T90) in marine water. A higher T90 average of 2.51 ± 0.08 was observed for the commensal and environmental strains. Generally, lower T90 values of 2.14 ± 0.26 and 2.15 ± 0.16 days respectively were observed for hospital and community acquired enterococci strains in fresh water mesocosms subjected to tropical ambient temperature. Beach water enterococci and enterococci recovered from faeces of humans survived for up to 20 days and 23 days respectively in fresh and marine waters. The epidemic strain, MMH594, an esp-positive clinical bacteremia isolate that previously caused multiple infections in a hospital ward outbreak fares favourably well in tropical marine and fresh aquatic environments. For enterococci, the decay rate was approximately 13% higher in fresh water than was observed for marine water. On the contrary, for E. coli, the decay rate was approximately 17% lower in fresh water than was observed in marine water. Generally, the whole, the population trends of E. coli and enterococci in fresh and marine water mesocosms did not reveal any evidence of growth. Our findings suggest that potentially pathogenic bacteria can resume active growth after three weeks of being harboured by the reservoir-beach sand and still pose threat to public health.

Origin of de novo daptomycin non susceptible enterococci

The emergence of daptomycin non-susceptible enterococci(DNSE) poses both treatment and infection control challenges.Clinicians should be vigilant that DNSE may be isolated from patients with or without(de novo DNSE) prior use of daptomycin.Recent epidemiological data suggest the presence of a community reservoir for DNSE which may be associated with environmental,foodborne and agricultural exposures.The mechanisms of nonsusceptibility to daptomycin have not been well characterized and may not parallel those for Staphylococcus aureus.The identification of daptomycin resistance genes in anaerobes,in farm animals and in an ecosystem that has been isolated for million years,suggest that the environmental reservoir for de novo DNSE may be larger than previously thought.Herein,the limited available scientific evidence regarding the possible origin of de novo DNSE is discussed.The current existing evidence is not sufficient to draw firm conclusions on the origin of DNSE.Further studies to determine the mechanisms of de novo daptomycin nonsusceptibility among enterococci are needed.

Prevalence of Multidrug Resistant Enterococci in a Tertiary Care Hospital in India: A Growing Threat

Introduction: Enterococci are members of the healthy human intestinal flora, but are also leading causes of highly antibiotic-resistant infections. Serious enterococcal infections are often difficult to treat since the organisms have a tremendous capacity to acquire resistance to penicillin, high concentration of aminoglycoside & vancomycin. Careful review of in vitro susceptibility data is required to treat infections caused by MDR Enterococci. Therefore we conducted the study to find out prevalence of MDR Enterococci. Aims & Objectives: To study the prevalence of Vancomycin resistance, High Level Streptomycin Resistance (HLSR) & High Level Gentamicin Resistance (HLGR) in different enterococcal isolates. Materials & Methods: Total 180 enterococcal isolates were studied. Identification was done by conventional biochemical methods. Antibiotic susceptibility testing was done by Kirby-Bauer disc diffusion method on Mueller–Hinton agar and results were interpreted as per CLSI guidelines. HLSR & HLGR was determined by disc diffusion method using high level Gentamicin disc (120 μg) & Streptomycin (300 μg) discs. Minimum inhibitory concentration (MIC) determination for Vancomycin was done by vancomycin E test strips. Results: Total 180 entetococcal isolates were studied. E. faecalis was 60%, E. faecium was 32.2%, E. durans and E. raffinosus were 4.4% & 3.3% respectively. Enterococcus fecium showed resistance in high percentage as compared to E. faecalis. 15 isolates were found to be vancomycin resistant. Conclusion: Resistance to aminoglycoside is of great concern. Regular screening of enterococcal isolates for vancomycin resistance detection should be implemented. It is very important to implement infection control measures, screening of health care workers, surveillance cultures in intensive care units which can control spread of multidrug resistant enterococci.

Biofilm Formation and Virulence Genes in Clinical Isolates of Enterococcus faecalis

Enterococcus faecalis is a Gram-positive bacterium commonly found in the gastrointestinal tract that can cause serious infections. Many enterococci have broad resistance to antibiotics including penicillin, cephalosporins, aminoglycosides and glycopeptides. There are several adaptation mechanisms that bacteria can undergo to become more resistant, among them is the formation of biofilm. Several genes have been linked to the increase in the capacity of biofilm formation by bacteria such as gelE, esp and asa1. The aim of this research was to evaluate the biofilm formation of 12 E. faecalis isolates collected in hospitals and a standard strain, as well as to evaluate the hydrophobicity of its membrane and the presence of virulence genes. All the isolates formed biofilm and the characteristics of their membrane were variable. In addition, the presence of at least one virulence gene was found in all the 12 isolates, and none of the genes in the standard strain, indicating the acquisition of these genes in the hospital environment. With this, we can conclude that there is a close relationship between biofilm formation, acquisition of antibiotic resistance and the presence of virulence genes.

In vitro study on the transmission of multidrug-resistant bacteria from textiles to pig skin

BACKGROUND The survival of microorganisms on textiles and specifically on healthcare profes-sionals’(HCP)attire has been demonstrated in several studies.The ability of microorganisms to adhere and remain on textiles for up to hours or days raises questions as to their possible role in transmission from textile to skin via HCP to patients.AIM To evaluate the presence,survival and transmission of different multidrug-resistant bacteria(MDRB)from HCP attire onto skin.METHODS Three MDRB[methicillin-resistant Staphylococcus aureus(MRSA);vancomycin-resistant Enterococcus faecium(VRE);carbapenem-resistant Klebsiella pneumoniae,(CRKP)]were inoculated on textiles from scrubs(60%cotton-40%polyester)and white coat(100%cotton)at concentrations of 108 colony-forming units(CFU),105 CFU,and 103 CFU per mL.The inoculation of swatches was divided in time intervals of 1 min,5 min,15 min,30 min,1 h,2 h,3 h,4 h,5 h,and 6 h.At the end of each period,textiles were imprinted onto pig skins and each skin square was inverted onto three different selective chromogenic media.Growth from the pig skin squares was recorded for the 3 MDRB at the three above concentrations,for the whole length of the 6-h experiment.RESULTS MRSA was recovered from pig skins at all concentrations for the whole duration of the 6-h study.VRE was recovered from the concentration of 108 CFU/mL for 6 h and from 105 CFU/mL for up to 3 h,while showing no growth at 103 CFU/mL.CRKP was recovered from 108 CFU/mL for 6 h,up to 30 min from 105 CFU/mL and for 1 min from the concentration of 103 CFU/mL.CONCLUSION Evidence from the current study shows that MRSA can persist on textiles and transmit to skin for 6 h even at low concentrations.The fact that all MDRB can be sustained and transferred to skin even at lower concentrations,supports that textiles are implicated as vectors of bacterial spread.

重症监护病房肠球菌感染及体外药敏监测

目的 研究医院重症监护病房 (ICU)内肠球菌的感染现状并对其耐药性进行体外药敏监测。方法 用法国 生物梅里埃公司生产的VITEK32全自动细菌鉴定系统鉴定肠球菌 ,用K B法及E test试条法监测肠球菌耐药率。结果 ICU内 116株肠球菌中 ,以粪肠球菌分离率最高 ,为 75 .0 % ,屎肠球菌为 10 .3% ,居第 2位 ,116株肠球菌中检出耐氨苄西林肠球菌 (ARE) 16 .4 % ,氨基糖苷类高水平耐药肠球菌 (HLAR) 38.8% ,氨基糖苷类高水平耐药合并氨苄西林耐药株 6 .9% ,未检出耐万古霉素肠球菌 (VRE) ,但检出万古霉素中介肠球菌 (VIE) 3 4 %。结论 ICU内肠球菌耐药率呈上升趋势 ,须严密监测 ,预防耐药肠球菌的暴发流行。

肠球菌抗生素耐药基因检测

目的明确解放军第98医院临床分离的肠球菌中,抗生素耐药相关基因存在状况。方法采用聚合酶链反应(PCR)及序列分析的方法,分析15株粪肠球菌和9株屎肠球菌中,β-内酰胺类抗生素耐药相关基因(TEM)、氨基糖苷类抗生素耐药相关基因(氨基糖苷类修饰酶基因)[aac(6′)/aph(2″)、aph(3′)-Ⅲ、ant(2″)-Ⅰ、ant(4′,4″)、ant(6)-Ⅰ]、四环素耐药相关基因(tetM)、红霉素耐药相关基因(ermB、mefA)和万古霉素耐药相关基因(vanA、vanB)。结果24株肠球菌中TEM、aac(6′)/aph(2″)、aph(3′)-Ⅲ、ant(2″)-Ⅰ、ant(4′,4″)、ant(6)-Ⅰ、ermB、mefAt、etM、vanA和vanB 4基因的阳性分别为9株(37.5%)、17株(70.8%)、6株(25.0%)、0、0、10株(41.7%)、18株(75.0%)、0、10株(41.7%)、1株(4.2%)和1株(4.2%)。结论临床分离的肠球菌多重耐药严重;携带抗生素相关耐药基因是导致菌株对抗生素产生耐药的重要原因。

万古霉素耐药肠球菌的同源性及耐药机制分析

目的探讨万古霉素耐药肠球菌(VRE)的同源性及主要耐药机制。方法收集我院临床分离的9株VRE,采用E-test法检测其对万古霉素等10种抗菌药物的最低抑菌浓度值,脉冲场凝胶电泳技术进行同源性分析,多重PCR技术扩增万古霉素耐药基因并测序。结果9株VRE均为屎肠球菌,共分为6个克隆,耐药表型和基因型均为vanA型。结论本院VRE为vanA基因型,VRE的增加与局部克隆传播、耐药基因的水平转移以及抗菌药物的选择压力有关。

肠球菌溶血素与其致病力的关系

目的 探讨肠球菌溶血素的毒力因子作用。方法 分别检测 3 9株临床标本分离的粪肠球菌以及 3 1株健康人群粪便分离的粪肠球菌的溶血素检出率 ;并检测了β溶血肠球菌、非 β溶血肠球菌对 9种抗生素的敏感性。 结果 临床菌株的溶血素检出率为 5 8.9% ,健康人群分离株的溶血素检出率为 19.3 % (P <0 .0 0 5 ) ;β溶血株对抗生素的耐药性明显高于非 β溶血株 (P <0 .0 1)。

临床分离肠球菌的耐药性监测与分析

目的 监测临床分离的 14 0株肠球菌对 16种常用抗菌药物的敏感性 ,为临床治疗肠球菌感染提供依据。方法 采用琼脂稀释法测定各抗菌药物对肠球菌的 MIC,计算 MIC50 、MIC90 和敏感率 ,采用快速硝噻吩纸片显色法对 14 0株肠球菌进行β-内酰胺酶测定。结果 万古霉素、替考拉宁对粪肠球菌和屎肠球菌的敏感性最高 ,均为10 0 % ,粪肠球菌对氨苄西林 /舒巴坦、亚胺培南和氨苄西林敏感率分别为 91.9%、90 .8%和 90 .8% ;屎肠球菌对氨苄西林 /舒巴坦、亚胺培南和氨苄西林分别为 92 .7%、82 .9%和 90 .2 % ;粪肠球菌、屎肠球菌以及其他肠球菌对头孢吡肟的敏感率最低分别为 14 .9%、9.8%和 0 ;青霉素和氨苄西林对粪肠球菌、屎肠球菌的药敏结果可推测对亚胺培南的敏感性。结论 万古霉素和替考拉宁仍是治疗肠球菌感染最有效的药物 。

猪源肠球菌的分离及生物特性的初报

本研究从猪粪便中分离了肠球菌两株 ,经菌种鉴定两株菌均为屎肠球菌。其生物特性的研究表明 :可耐受 1%的胆盐和 6 % Na Cl高盐 ,在 p H3.0条件下可存活 ,对绝大多数抗生素耐药。

儿童肠球菌多重耐药与Ⅰ类整合子的检测

目的了解儿童临床分离肠球菌的耐药特征及其多重耐药与Ⅰ类整合子的相互关系。方法采用琼脂稀释法测定常用抗菌药物对152株肠球菌的最低抑菌浓度(MIC),用聚合酶链反应(PCR)检测肠球菌Ⅰ类整合子和Ⅰ类整合酶基因。结果屎肠球菌对氨苄西林、阿莫西林-克拉维酸、环丙沙星的耐药率分别为96.8%、95.2%和84.1%,粪肠球菌对上述3种抗菌药物的耐药率分别为23.6%、18.0%和49.4%,屎肠球菌的耐药率明显高于粪肠球菌(P<0.001);粪肠球菌中有2株对万古霉素的MIC为8μg/mL,粪肠球菌和屎肠球菌对替考拉宁均敏感。儿童多重耐药肠球菌发生率高达93.7%。屎肠球菌耐药模式以耐氨苄西林、红霉素、环丙沙星、利福平、四环素、高水平庆大霉素6种抗菌药物为主,占屎肠球菌的59%,粪肠球菌以耐四环素、红霉素、利福平、氯霉素、高水平庆大霉素5种抗菌药物为主,占粪肠球菌的26%。全部152株肠球菌未检测到Ⅰ类整合子,仅有5株检测到Ⅰ类整合酶基因。结论儿童肠球菌多重耐药十分严重,儿童肠球菌多重耐药与Ⅰ类整合子和Ⅰ类整合酶基因尚无明显关系。

906株肠球菌属细菌的耐药性分析

目的 :了解本地肠球菌属细菌的耐药性变化 ,为临床经验用药提供参考。方法 :对 1998～ 2 0 0 3年临床分离之肠球菌属细菌进行耐药趋势分析。结果 :90 6株肠球菌属细菌以粪肠球菌和屎肠球菌为主 ,占 87 86 % ,高浓度庆大霉素耐药 (HLGR)肠球菌分离率为 6 1 4 1% ,万古霉素耐药肠球菌 (VRE)分离率为 0 4 4 % ,对青霉素、氨苄西林、环丙沙星的耐药率呈逐年增加趋势 ;粪肠球菌对青霉素的耐药率为 14 0 7% ,而屎肠球菌对青霉素耐药率达 83 33% ,对相同抗生素的耐药率屎肠球菌明显高于粪肠球菌。结论 :肠球菌对临床常用抗生素以万古毒素最敏感 ,但青霉素类药物仍不失为治疗粪肠球菌的首选 ;对于屎肠球菌、HLGR、VRE等感染的治疗 ,应全面考虑肠球菌对不同抗生素的耐药水平 ,采取联合用药 ;而实验室对于肠球菌属的正确鉴定、分型、耐药监测以及临床治疗肠球菌感染中有效控制抗生素疗程 ,缩短平均住院日也是控制肠球菌耐药传播的有效手段之一。

肠球菌在家蚕消化道中的分布

用ＡＰＩ２０ ＳＴＲＥＰ（Ｖ５０） 系统对从健康家蚕消化道来源的８９ 株肠球菌菌株进行数值分类学研究的结果表明：在分离菌株中分布着Ｅｎｔ．ｃａｓｓｅｌｉｆｌａｖｕｓ、Ｅｎｔ．ｆａｅｃａｌｉｓ、Ｅｎｔ．ａｖｉｕｍ 、Ｅｎｔ．ｄｕｒａｎｓ 和Ｅｎｔ．ｇａｌｌｉｎａｒｕｍ 等菌种，其分布频率分别为３２６ ％ 、２５９％ 、１５７ ％ 、３４ ％ 和２２ ％ 。其余１８ 个菌株未能被该系统所分类。Ｅｎｔ．ｃａｓｓｅｌｉｆｌａｖｕｓ 和Ｅｎｔ．ｆａｅｃａｌｉｓ 是家蚕消化道内的主要肠球菌菌丛。Ｅｎｔ．ｃａｓｓｅｌｉｆｌａｖｕｓ 在５ 龄初和末的分布频率较高，Ｅｎｔ．ｆａｅｃａｌｉｓ 在５ 龄第４ 和第５ 天的分布频率较高。