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.

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.

Extensive contact tracing and screening to control the spread of vancomycin-resistant Enterococcus faecium ST414 in Hong Kong

Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong. Methods We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing （MLST） was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE. Results Between November 26 and December 17, 2011, 11 patients （1 exogenous case and 10 secondary cases） in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% （10/361）. There were 8 males and 3 females with a median age of 78 years （range, 40-87 years）. MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay （P 〈0.001）, a higher proportion with chronic cerebral and cardiopulmonary conditions （P=0.001）, underlying malignancies （P 〈0.001）, and presence of urinary catheter （P 〈0.001）, wound or ulcer （P 〈0.001）, and a greater proportion of these patients were receiving β-lactam/ β-1actamase inhibitors （P=0.009）, carbapenem group （P 〈0.001）, fluoroquinolones （P=0.003）, or vancomycin （P=0.001） when compared with the controls. Conclusion Extensive contact tracing and screening with a ＂search-and-confine＂ strategy was a successful tool for outbreak control in our healthcare reqion.

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.

Success of linezolid therapy for postneurosurgical ventriculitis due to vancomycin-resistant Enterococcus faecium: case report and literature review

Background:Vancomycin-resistant Enterococcus faecium ventriculitis is one of the most severe events in postneurosurgical intracranial infections.There are no guidelines recommending an appropriate treatment before.Case presentation:This case presents a successful linezolid treatment for post-neurosurgical vancomycin-resistant Enterococcus faecium ventriculitis of a 24-year-old man in the department of neurosurgery,Beijing Tiantan Hospital.Conclusions:Linezolid should be considered as one of the important methods for the treatment of postneurosurgical intracranial infections caused by vancomycin-resistant Enterococcus.

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.

Exogenous endophthalmitis caused by Enterococcus casseliflavus:A case report

BACKGROUND Endophthalmitis caused by Enterococci is rare,and cases involving vancomycinresistant enterococci are even rarer.We report the first case of Enterococcus casseliflavus endophthalmitis associated with injury caused by a pig.We also review reported cases of exogenous endophthalmitis caused by Enterococcus casseliflavus and discuss the clinical management and prognosis of this disease.CASE SUMMARY A 43-year-old man with no previous visual problems complained of endophthalmitis in his left eye following injury caused by a pig.Visual acuity was light perception and B-ultrasonography revealed vitreous opacities with retinal detachment.He was treated with intravitreal vancomycin and ceftazidime after refusing vitrectomy.However,the vitreous opacities and retinal detachment deteriorated and he underwent vitrectomy 5 d post-injury.Intraoperatively,advanced rhegmatogenous and tractional retinal detachment with proliferative vitreoretinopathy were observed.On postoperative day 5,vitreous cultures grew Gram-positive cocci identified as Enterococcus casseliflavus.A 2-wk course of intravenous ampicillin and dexamethasone was commenced.On postoperative day 14,visual acuity improved to hand movement.At 6 mo post-injury,visual acuity improved to 20/667,but optic atrophy was present.CONCLUSION Systemic administration of linezolid in the treatment of Enterococcus casseliflavus endophthalmitis can improve visual acuity.However,intravitreal amikacin should be considered despite concerns of toxicity when oral linezolid fails to prompt improvement.

Effect of Photoactivated Hypericin on Growth and Antibiotic Susceptibility of Hospital-Related Staphylococcus aureus and Enterococcus sp. Clinical Strains

Resistance against commonly used antibiotics is a serious clinical problem in recent medical practice. There exist several bacterial strains in which the possibilities of their inhibition are very limited due to multidrug resistance. Antimicrobial photodynamic therapy (aPDT) represents an option how to effectively suppress the growth of resistant pathogens. In this work we have studied interactions of potent photosensitizer hypericin (Hyp) with hospital-related gram positive (Gram+) and gram negative (Gram-) bacterial strains and the effects of photodynamic activated Hyp on bacterial susceptibility and/or resistance of these strains to antibiotics. We demonstrated a significant influence of photoactivated Hyp on growth of Staphylococcus aureus and Enterococcus sp. We have also shown that it is extremely important to use the effective concentrations of Hyp for aPDT, which completely inhibit the growth of microorganisms. Otherwise, there appears an increase in resistance, probably due to the activation of efflux mechanisms, which are involved in the efflux of Hyp and antibiotics as well.

Tubastraea coccinea: A Non-Indigenous Coral (Cnidaria, Scleractinia) Collected at Arvoredo Island, South of Brazil with Potential MRSA and VRE Antimicrobial Activity

Bacterial infection is considered to be one of the most critical health issues of the world. It is essential to overcome this problem by the development of new drugs. Marine organisms as corals, sponges, seaweeds, and other are an incredible source of novel pharmacologically active compounds. Herein, the antimicrobial activity (extract/fractions) of the invasive stony coralTubastraea coccinea was evaluated by the disk diffusion method against 21 microbial strains (ATCC and clinical strains). Micro broth dilution was used to determinate the MIC of the fractions that showed antimicrobial activity by the disk diffusion method. Bioautography assay was also performed. Our results showed that the n-butanol (BF) and aqueous fractions (AF) showed activity against ATCC strains Staphylococcus aureus (MIC 31.25 and 250 μg/mL),Salmonella typhimurium (MIC 125 and 500 μg/mL), Escherichia coli (MIC 62.5 and 500 μg/mL) and Pseudomonas aeruginosa (MIC 62.5 and 500 μg/mL), respectively. Moreover, BF fraction was also effective against the clinical strains S. aureus(MIC 62.5 μg/mL), Klebsiella pneumoniae Carbapenemase—KPC (MIC 125 μg/mL), Methicillin-Resistant Staphylococcus aureus—MRSA (MIC 125 μg/mL) and Vancomycin-Resistant Enterococcus faecalis—VRE (MIC 62.5 μg/mL). The ratio MBC/MIC reinforces the bactericidal profile of BF fraction. The bioautography assay of BF fraction showed the presence of antimicrobial components at Rf0.55.

Tracing enterococci persistence along a pork production chain from feed to food in China

The prevalence and transmission of vancomycin-resistant Enterococcus(VRE)in enterococci being as probiotics has been neglected in the scientific literature.The application of enterococci in feed,food and health products may cause VRE transmission through the food chain.This study evaluated phenotypic resistance of Enterococcus species to 20 antibiotics along a pork production chain from feed to food.It also assessed the genetic diversity of Enterococcus faecium isolates.A total of 510 samples(feed,n=70;swine manure,n=400;swine carcasses,n=20,and retail pork,n=20)were collected in Beijing,China.A total of 328 enterococci isolates with 275 E.faecium and 53 Enterococcus faecalis were identified using 16 S rRNA.Antimicrobial susceptibility to all enterococci isolates was conducted using the KeB method for 20 antibiotics from 9 categories.Multilocus sequence typing(MLST)was conducted on the E.faecium isolates to survey the dissemination of enterococci in the pig industry.The results showed that only 26 enterococci isolates were sensitive to the 20 antibiotics,while half of the isolates(164/328)had acquired multi-drug resistance.The resistant rate to furazolidone was 68.60%,followed by 42.99%to tetracycline.One vancomycin-resistant E.faecium isolates were isolated from feed origin and 2 from manure origin,with minimum inhibitory concentrations to vancomycin of 1,024,64,and 64 mg/mL,respectively.The MLST outcomes showed that the 275 E.faecium isolates belonged to 11 sequence types(ST)including ST40,ST60,ST94,ST160,ST178,ST296,ST361,ST695,ST726,ST812 and ST1014.The ST of the feedsourced VRE was ST1014,while the 2 manure-sourced VRE was ST69.ST1014 evolved from ST78,which was the dominant clonal complex in most cities of China,leading to the spreading of VRE.These findings revealed the potential safety hazards of commercial probiotic enterococci in China and showed that there is a risk of the VRE horizontally transferring from feed to food.