Multiresistant Pathogens Research Articles

Community-acquired pneumonia

Community acquired pneumonia (CAP) is an infection with a limited spectrum of pathogens. Pneumonias acquired in a hospital or under immunoincompetence are being treated according to different algorithms. The concept of health care associated pneumonia (HCAP) is discarted. It is not capable to predict a high probability of multiresistant pathogens.

Current Aspects on the Pathogenesis of Urinary Tract Infections

Urinary tract infections are among the most common bacterial infectious diseases worldwide. Every second woman will experience at least one urinary tract infection in her lifetime. The administration of antibiotics has been a safe and efficient treatment modality so far. However, due to the emergence of multi-resistant pathogens and the developmental void of new antimicrobial drugs, the therapy of infections mighty become more challenging in the near future. So, knowledge of the complex host-pathogen interaction is of great importance. Common phenotypes observed in clinical practice suggest basic principles, which are relevant for the development of novel antimicrobial strategies. With invading pathogens forming intracellular bacterial communities they evade host response and provide a nidus for recurrent infection. A plethora of virulence factors allow uropathogenic bacteria to colonize and to establish infections in the urinary tract. In response, host responses seem to address specific virulence mechanisms that are essential to pathogenicity. Deciphering the molecular mechanisms underlying the complex host-pathogen interaction is critical to devise novel treatment options.

Evaluation of the Antibacterial Activity of Micromeria barbata in Lebanon

This study aims to evaluate the antimicrobial activity of the essential oil of the plant Micromeria barbata (M. barbata) against the Gram negative and Gram positive bacterial strains (from wild type strains and strains that have multiple mechanisms of resistance to antibiotics), as well as against a clinical strain of Candida albicans (C. albicans). The essential oil was obtained by Clevenger steam distillation. The composition of the essential oil in question as well as the concentrations of each component was determined by GC-MS. Clinically isolated strains were used, and their sensitivity to antibiotics was determined using the well diffusion method, while the resistance mechanism was determined through molecular methods. The activity of the essential oil against all tested strains was carried out using the diffusion method, and the Minimum Inhibitory Concentration (MIC) was determined using the dilution method on agar. The results of the antimicrobial activity showed that the oil had a good activity on wild strains and on strains having different mechanisms of resistance. The oil in question has a significant activity on all tested microorganisms. The broad spectrum of the antimicrobial activity of the oil, especially that directed against multi-resistant pathogens involved in human infections, make it useful to use this oil for the formulation of new drugs used to treat microbial infections, especially infections with antibiotic-resistant strains.

Periprosthetic joint infections in modular endoprostheses of the lower extremities: a retrospective observational study in 101 patients.

BackgroundModular mega-endoprosthesis systems are used to bridge very large bone defects and have become a widespread method in orthopaedic surgery for the treatment of tumours and revision arthroplasty. However, the indications for the use of modular mega-endoprostheses must be carefully considered. Implanting modular endoprostheses requires major, complication-prone surgery in which the limited salvage procedures should always be borne in mind. The management of periprosthetic infection is particularly difficult and beset with problems.Given this, the present study was designed to gauge the significance of periprosthetic infections in connection with modular mega-implants in the lower extremities among our own patients.MethodsPatients who had been fitted with modular endoprosthesis on a lower extremity at our department between September 1994 and December 2011 were examined retrospectively. A total of 101 patients with 114 modular prostheses were identified. Comprising 30 men (29.7 %) and 71 women (70.3 %), their average age at the time of surgery was 67 years (18–92 years).ResultsThe average follow-up period was 27 months (5 months and 2 weeks to 14 years and 11 months) and the drop-out rate was about 8.8 %. Altogether, there were 19 (17.7 %) endoprosthesis infections: 3 early infections and 16 late or delayed infections. The pathogen spectrum was dominated by coagulase-negative staphylococci (36 %) and Staphylococcus aureus (16 %), including 26 % multi-resistant pathogens. Reinfection occurred in 37 % of cases of infection. Tumours were followed by significantly fewer infections than the other indications. Infections were twice as likely to occur after previous surgery.ConclusionIn our findings modular endoprostheses (18 %) are much more susceptible to infection than primary endoprostheses (0.5–2,5 %). Infection is the most common complication alongside the dislocation of proximal femur endoprostheses. Consistent, radical surgery is essential – although even with an adequate treatment strategy, the recurrence rate is very high. Unfortunately, the functional results are frequently unsatisfactory, with amputation often being the last resort. Therefore, the indication for implantation must be carefully considered and discussed in great detail, especially in the case of multimorbid patients with previous joint infections.

Bioinformatics Tools for the Discovery of New Nonribosomal Peptides.

This chapter helps in the use of bioinformatics tools relevant to the discovery of new nonribosomal peptides (NRPs) produced by microorganisms. The strategy described can be applied to draft or fully assembled genome sequences. It relies on the identification of the synthetase genes and the deciphering of the domain architecture of the nonribosomal peptide synthetases (NRPSs). In the next step, candidate peptides synthesized by these NRPSs are predicted in silico, considering the specificity of incorporated monomers together with their isomery. To assess their novelty, the two-dimensional structure of the peptides can be compared with the structural patterns of all known NRPs. The presented workflow leads to an efficient and rapid screening of genomic data generated by high throughput technologies. The exploration of such sequenced genomes may lead to the discovery of new drugs (i.e., antibiotics against multi-resistant pathogens or anti-tumors).

Influence of Sanitizing Methods on Healthcare-Associated Infections Onset: A Multicentre, Randomized, Controlled Pre-Post Interventional Study

Background: Contamination of healthcare surfaces contributes to Healthcare-associated infections (HAIs) transmission, representing a global concern. Conventional chemicals-based sanitation shows limitations in controlling surface contamination and related HAIs onset, and can select multi-resistant pathogen species. Recently, a sanitizing procedure involving probiotic-based detergents was shown to decrease surface pathogens up to 90% more than conventional disinfectants, without selecting resistant species. This study aims to analyse the influence of a probiotic-based sanitizing intervention on HAIs incidence and typology. Design: Seven Italian hospitals representative of all Italian geographical areas will be recruited for participation in a multicentre, prospective, randomised, pre-post interventional study, analysing simultaneously for a consecutive 18- months period both microbial surface contamination and HAIs occurrence. The intervention will consist in the substitution of the conventional cleaning procedure (chlorine-based) with a probiotic-based one. In the preintervention phase, hospitals will maintain conventional sanitizing procedures; in the post-intervention phase, the probiotic-based sanitation will be applied, allowing a buffer period for the stabilization of the new method. The participating hospitals will be randomly allocated in the following groups: no-intervention (one hospital), intervention-1st group (three hospitals) and intervention-2nd group (three hospitals), entering the study with a 5- months delay. During the whole study period, all patients admitted to the recruited hospital wards will be continuously surveyed for HAI occurrence. Meanwhile, surface bioburden will be monitored monthly by both biological and molecular assays. Discussion: This study will be the first to provide robust data on the impact of sanitation procedures on healthcare associated infections onset and typology, as no previously reported studies evaluates simultaneously and continuously for a period of 18 months both the environmental surface bioburden, its resistome and the healthcare associated infections onset. Results: The results generated from this study might be important for the development of future guidelines to modulate environmental microbiota and to ameliorate hospital environmental cleaning, implementing prevention strategies to reduce HAIs onset.

Relationship Between Isolating Multi-Drug Resistant A. Baumannii and K. Pneumoniae in Bronchial Aspirate and Subsequently in Blood Cultures: Evaluation of Colistin Aerosol Therapy in Intensive Care Patients

Klebsiella pneumoniae (K. pneumoniae) and Acinetobacter baumannii (A. baumannii) are multiresistant pathogens most frequently found in patients hospitalized in the Intensive Care of our hospital. We found the highest rate of positivity in the bronchial aspirates, often followed by a similar observation in blood culture. We carried out a study to evaluate the reduction of sepsis that developed after the detection of these microorganisms in bronchial aspirate, following the introduction of treatment with colistin aerosol in combination with conventional therapy. From 2012 to the first half of 2014, 533 patients were admitted to the ICU of our hospital. Since May 2013, colistin was administered by aerosol along with conventional therapy. In 43 (78.1%) cases K. pneumoniae KPC was isolated from bronchial aspirate and in 30 (54.5%) from blood culture; MDR A. baumannii was isolated in 89 (96.7%) cases of bronchial aspirate and 45 (48.9%) from blood culture. From patients treated with added colistin aerosol, K. pneumoniae KPC was isolated from bronchial aspirates in 15 cases and in 4 (26.7%) of those was found sepsis. MDR A. baumannii was isolated from bronchial aspirate in 41 cases, and in 10 (24.4%) it developed sepsis due to the same germ. The patients admitted to intensive care for more than 7 days were positive for MDR A. baumannii and MDR K. pneumoniae in bronchial aspirates and subsequent relief of blood culture. The treatment with colistin aerosol resulted in a reduction of the spread of microorganisms from the lower respiratory tract to the blood.

Horizontal gene transmission of the cfr gene to MRSA and Enterococcus: role of Staphylococcus epidermidis as a reservoir and alternative pathway for the spread of linezolid resistance.

Linezolid resistance mediated by the cfr gene represents a global concern due to its dissemination among multiresistant nosocomial pathogens such as MRSA and Enterococcus. In the present work, we have evaluated the in vitro transmission of cfr pSCFS7-like plasmids from two Staphylococcus epidermidis ST2 strains (SE45 and SE50) isolated in Spanish hospitals, to clinical MRSA and Enterococcus spp. isolates obtained in Japan, a country in which cfr has not been detected yet. We have also investigated alternative mechanisms of horizontal gene transfer involved in the spread of the cfr gene. MRSA (n = 16) and Enterococcus spp. (n = 8) clinical isolates were used as recipients in conjugative experiments. Bacteriophage-mediated transmission was tested using MR83a phage and N315, COL and Mu50 strains. A transformation assay was carried out using a natural competent strain derived from N315. The SE45 strain was able to transfer the cfr gene to all strains tested, while transmission from SE50 was observed only to a few strains and with less efficiency. No transmission was observed to Enterococcus spp. isolates. Even though conjugation is thought to be the main mechanism of cfr dissemination, we have demonstrated that transduction can be considered an alternative pathway for transmission of the cfr gene between MRSA strains. However, the results suggest an absence of transmission by natural transformation. Linezolid resistance mediated by cfr vectors, such as pSCFS7-like plasmids, can be efficiently transferred to clinical MRSA in Japanese isolates. After reaching the staphylococcal pool, the cfr gene could be spread among MRSA strains by either conjugation or transduction.

ANTIMICROBIAL ACTIVITY OF DRACAENA CINNABARI RESIN FROM SOQOTRA ISLAND ON MULTI DRUG RESISTANT HUMAN PATHOGENS

Background: Few studies showed that Dracaena cinnabari resin, collected from Soqotra Island, Yemen, has antimicrobial activity. This study
 is the first to investigate antimicrobial activity of the resin on both antibiotic multi-resistant human pathogens and on poly-microbial culture.
 Material and Methods: Antimicrobial activity of ethanolic extract of Dracaena cinnabari resin from Soqotra Island on multidrug resistant
 Gram-positive and Gram-negative human ATCC standard pathogens and Ascosphaera apis, the causal organism of chalkbrood disease of
 honeybee was studied using the agar disc diffusion method. The minimal inhibitory concentration of extracts was carried out by the broth micro
 dilution method.
 Results: Ethanolic extract of Dracaena cinnabari resin showed a considerable antimicrobial activity against all the pathogens tested. The zone
 of inhibition were between 4.9-11.5 mm. The most sensitive microbe was Staphylococcus aureus and least sensitive was Aspergillus nidulans.
 The minimal inhibitory concentration of the extract against Escherichia. coli ATCC 10402, Klebsiella pneumonia ATCC 10031, and
 Staphylococcus aureus ATCC 29212 was 1.25 μg/mL (w/v) and for the other pathogens (Candida albicans ATCC 10231, Salmonella
 typhimurum ATCC 3311 and Pseudomonos aeruginosa ATCC 2785) was 2.5 μg/mL (w/v).
 Conclusion: Ethanolic extract of Dracaena cinnabari resin has a considerable antimicrobial activity against Gram-positive and Gram-negative
 human pathogens and fungi. This extract might possess a role in the management of microbial infections in human and honeybee disease.

Outcomes and risk factors for cancer patients undergoing endoscopic intervention of malignant biliary obstruction.

BackgroundMalignant bile duct obstruction is a common problem among cancer patients with hepatic or lymphatic metastases. Endoscopic retrograde cholangiography (ERC) with the placement of a stent is the method of choice to improve biliary flow. Only little data exist concerning the outcome of patients with malignant biliary obstruction in relationship to microbial isolates from bile.MethodsBile samples were taken during the ERC procedure in tumor patients with biliary obstruction. Clinical data including laboratory values, tumor-specific treatment and outcome data were prospectively collected.Results206 ERC interventions in 163 patients were recorded. In 43 % of the patients, systemic treatment was (re-) initiated after successful biliary drainage. A variety of bacteria and fungi was detected in the bile samples. One-year survival was significantly worse in patients from whom multiresistant pathogens were isolated than in patients, in whom other species were detected. Increased levels of inflammatory markers were associated with a poor one-year survival. The negative impact of these two factors was confirmed in multivariate analysis.In patients with pancreatic cancer, univariate analysis showed a negative impact on one-year survival in case of detection of Candida species in the bile. Multivariate analysis confirmed the negative prognostic impact of Candida in the bile in pancreatic cancer patients.ConclusionOutcome in tumor patients with malignant bile obstruction is associated with the type of microbial biliary colonization. The proof of multiresistant pathogens or Candida, as well as the level of inflammation markers, have an impact on the prognosis of the underlying tumor disease.

Antimicrobial effect on some zoonotic bacteria, of the cell-free fermentation fluid and purified peptide fraction of the entomopathogenic bacterium, Xenorhabdus budapestensis

Many multi-resistant patogens appear continuously resulting in a permanent need for the development of novel antibiotics. A large number of antibiotics introduced in clinical and veterinary practices are not effective. Antibacterial peptides with unusual mode of action may represent a promising option against multi-resistant pathogens. The entomopathogenic Xenorhabdus budapestensis bacteria produce several different antimicrobial peptides compounds such as bicornutin-A and fabclavin. The aim of the authors was to evaluate the in vitro antibacterial effect of Xenorhabdus budapestensis using zoonotic patogen bacteria. Cell-free conditioned media and purified peptide fractions of Xenorhabdus budapestensis were tested on Gram-positive (Rhodococcus equi, Erysipelothrix rhusiopathia, Staphylococcus aureus, Streptococcus equi, Corynebacterium pseudotuberculosis, Listeria monocytagenes) and Gram-negative bacteria (Salmonella gallinarum, Salmonella derbi, Bordatella bronchoseptica, Escherichia coli, Pasteurella multocida, Aeromonas hydrophila) using agar diffusion test on blood agar plates. It was found that Xenorhabdus budapestensis bacteria produced compounds with strong and dose-dependent effects on the tested organisms. Purified peptid fraction exerted a more marked effect than cell free conditioned media. Gram-positive bacteria were more sensitive to this antibacterial effect than Gram-negative bacteria. Antibacterial peptide compound from Xenorhabdus budapestensis exert marked antibacterial effect on zoonotic patogen bacteria and they should be further evaluated in future for their potential use in the control or prevention of zoonoses.

Multidrug-Resistant Organisms (MDRO) in Rehabilitation Clinics in the Rhine-Main-District, Germany, 2014: Prevalence and Risk Factors

While a limited number of studies have investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in medical rehabilitation institutions, almost no data on the colonization of rehabilitation patients with multiresistant gram-negative rods is available. Here we report on a large multicenter study on the prevalence of MRSA and multiresistant pathogens in rehabilitation institutions in the Rhine-Main area in 2014. Altogether, 21 rehabilitation hospitals participated. For all patients, age, gender, previous history of hospitalizations, surgery, previous colonization with multidrug-resistant organisms, use of a medical device, current antimicrobial therapy, and the current infection status were ascertained. On voluntary basis, nare and throat swabs were taken for analysis of MRSA and rectal swabs were tested for extended spectrum betalactamase-producing gram-negative bacteria (ESBL). 50% of 2 440 patients had a history of hospitalization within the previous 6 months while 39% had undergone surgery during the past 30 days. Approximately a quarter of the patients had been transferred to a rehabilitation hospital directly from an acute care hospital, had been under antimicrobial therapy with the past three months, or had travelled to a foreign country within the previous year. Risk factors such as lesions of the intact skin or presence of medical devices were rarely reported (< 5%) within the exception of patients undergoing geriatric or neurologic acute care rehabilitation. 0.7% (15/2155) of the patients were colonized with MRSA, while 7.7% (110/1434) showed a positive result for ESBL. The highest prevalence rates for multiresistant organisms were encountered among patients with neurologic rehabilitation (MRSA, 1.3%, and ESBL, 10.2%) or with geriatric rehabilitation (MRSA, 9.4%, and ESBL, 22.7%). In the rehabilitation patient population, the prevalence rates of MRSA and ESBL were found to be in the range of rates encountered in the general population (reported rates for MRSA, 0.5%, and ESBL, 6.3%). The known risk factors for MRSA such as skin lesions, medical devices and previous history for MRSA were also confirmed among this patient population. Direct transfer from an acute care hospital, antimicrobial treatment during the past 3 months, and wounds proved significant risk factors for ESBL colonization. Patients of neurologic rehabilitation and geriatric patients showed the highest rates of risk factors and the highest prevalence rates of multidrug-resistant organisms. It appears to be of importance for rehabilitation hospitals to be geared to the needs of patients with multidrug-resistant organisms, and prevent the transmission of these pathogens by appropriate hygiene measures.

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana.

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype bla CTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential sources for human exposure to BLP E. coli.

Short Proline-Rich Antimicrobial Peptides Inhibit Either the Bacterial 70S Ribosome or the Assembly of its Large 50S Subunit.

Short proline-rich antimicrobial peptides (PrAMPs) are a promising class of antibiotics that use novel mechanisms, thus offering the potential to overcome the health threat of multiresistant pathogens. The peptides bind to the bacterial 70S ribosome and can inhibit protein translation. We report that PrAMPs can be divided into two classes, with each class binding to a different site, and thus use different lethal mechanisms. Oncocin-type peptides inhibit protein translation in Escherichia coli by binding to the exit tunnel of the 70S ribosome with half maximal inhibitory concentrations (IC50 values) of around 2 to 6 μmol L(-1), whereas apidaecin-type peptides block the assembly of the large (50S) subunit of the ribosome, resulting in similar IC50 values. The revealed mechanisms should allow the design of new antibiotics to overcome current bacterial resistance mechanisms.

Structure-Function Relationships of Antimicrobial Peptides and Proteins with Respect to Contact Molecules on Pathogen Surfaces

The Antimicrobial peptides (e.g. defensins, hevein-like molecules and food-protecting peptides like nisin) are able to interact specifically with contact structures on pathogen surfaces. Besides protein receptors, important recognition points for such contacts are provided by pathogen glycan chains or surface lipids. Therefore, structural data concerning surface exposed glycans and lipids are of the highest clinical interest since these recognition functions play a key role when optimising anti-infection therapies. Approaches in nanomedicine and nanopharmacology in which various biophysical techniques such as NMR (Nuclear Magnetic Resonance), AFM (Atomic Force Microscopy), SPR (Surface Plasmon Resonance) and X-ray crystallography can be combined with biochemical and cell-biological methods will lead to improved antimicrobial peptides by this rational drug design approach. Such a strategy is extremely well suited to support clinical studies focussing on an effective fight against multiresistant pathogens. The data sets which are described here can be considered as universal for the design of various antimicrobial drugs against certain pathogens (bacteria, viruses and fungi) which cause severe diseases in humans and animals. Furthermore, these insights are also helpful for progressing developments in the field of food conservation and food preservation. A detailed analysis of the structure-function relationships between antimicrobial peptides and contact molecules on pathogen surfaces at the sub-molecular level will lead to a higher degree of specificity of antimicrobial peptides.

Development of new antibiotics: taking off finally?

Since 2010, awareness of the global threat caused by antimicrobial resistance (AMR) has risen considerably and multiple policy and research initiatives have been implemented. Research and development (R&D) of much-needed new antibiotics active against multiresistant pathogens is a key component of all programmes aiming at fighting AMR, but it has been lagging behind owing to scientific, regulatory and economic challenges. Although a few new antibiotics might be available in Switzerland in the next 5 years, these new agents are not based on new mechanisms of action and are not necessarily active against resistant pathogens for which there is the highest unmet medical need, i.e. multiresistant Gram-negative bacteria. Of the three new antibiotics with pending authorisation in Switzerland for systemic treatment of severe infections, oritavancin and tedizolid target Gram-positive pathogens, while only ceftolozane+tazobactam partially covers multiresistant Gram-negative pathogens. Among six antibiotics currently in phase III of clinical development, delafloxacin and solithromycin will also be useful mostly for Gram-positive infections. Importantly, the four other compounds are active against multiresistant Gram-negative pathogens: ceftazidime+avibactam, meropenem+RPX7009, eravacycline and plazomicin. The three last compounds are also active against carbapenem-resistant Enterobacteriaceae (CRE). A few compounds active against such pathogens are currently in earlier clinical development, but their number may decrease, considering the risk of failure over the course of clinical development. At last, through public and political awareness of pathogens with high public health impact and unmet medical need, development of innovative economic incentives and updated regulatory guidance, R&D of new antibiotics is slowly taking off again.

Influence of the yjiL-mdtM Gene Cluster on the Antibacterial Activity of Proline-Rich Antimicrobial Peptides Overcoming Escherichia coli Resistance Induced by the Missing SbmA Transporter System.

In view of increasing health threats from multiresistant pathogens, antimicrobial peptides (AMPs) and, specifically, proline-rich AMPs (PrAMPs) have been investigated in animal models. PrAMPs enter bacteria via the ABC transporter SbmA and inhibit intracellular targets. We used phage transduction (Tn10 insertion) to screen by random mutagenesis for alternative uptake mechanisms for analogs of apidaecin 1b, a honeybee-derived PrAMP. All 24 apidaecin-resistant mutants had the Tn10 insertion in the sbmA gene. These sbmA::Tn10 insertion mutants and the Escherichia coli BW25113 ΔsbmA (JW0368) strain were still susceptible to the bactenecin PrAMP Bac7(1-35) and oncocin PrAMPs Onc18 and Onc112, as well as to Chex1-Arg20, despite significantly reduced internalizations. In a second round of random mutagenesis, the remaining susceptibility was linked to the yjiL-mdtM gene cluster. E. coli BW25113 and its ΔyjiL null mutant (JW5785) were equally susceptible to all PrAMPs tested, whereas the BW25113 ΔmdtM mutant was less susceptible to oncocins. The JW0368 yjiL::Tn10 transposon mutant (BS2) was resistant to all short PrAMPs and susceptible only to full-length Bac7 and A3-APO. Interestingly, PrAMPs appear to enter bacteria via MdtM, a multidrug resistance transporter (drug/H(+) antiporter) of the major facilitator superfamily (MFS) that can efflux antibiotics, biocides, and bile salts. In conclusion, PrAMPs enter bacteria via ABC and MFS transporters that efflux antibiotics and cytotoxic compounds from the cytoplasm to the periplasm.

Auranofin efficacy against MDR Streptococcus pneumoniae and Staphylococcus aureus infections.

Auranofin is an FDA-approved, gold-containing compound in clinical use for the oral treatment of rheumatoid arthritis and has been recently granted by the regulatory authorities due to its antiprotozoal properties. A reprofiling strategy was performed with a Streptococcus pneumoniae phenotypic screen and a proprietary library of compounds, consisting of both FDA-approved and unapproved bioactive compounds. Two different multiresistant S. pneumoniae strains were employed in a sepsis mouse model of infection. In addition, an MRSA strain was tested using both the thigh model and a mesh-associated biofilm infection in mice. The repurposing approach showed the high potency of auranofin against multiresistant clinical isolates of S. pneumoniae and Staphylococcus aureus in vitro and in vivo. Efficacy in the S. pneumoniae sepsis model was obtained using auranofin by the oral route in the dose ranges used for the treatment of rheumatoid arthritis. Thioglucose replacement by alkyl chains showed that this moiety was not essential for the antibacterial activity and led to the discovery of a new gold derivative (MH05) with remarkable activity in vitro and in vivo. Auranofin and the new gold derivative MH05 showed encouraging in vivo activity against multiresistant clinical isolates of S. pneumoniae and S. aureus. The clinical management of auranofin, alone or in combination with other antibiotics, deserves further exploration before use in patients presenting therapeutic failure caused by infections with multiresistant Gram-positive pathogens. Decades of clinical use mean that this compound is safe to use and may accelerate its evaluation in humans.

Micelle Bound Structure and Model Membrane Interaction Studies of the Peptide Hylin a1 from the Arboreal South American Frog Hypsiboas albopunctatus.

Antimicrobial peptides (AMPs) appear as a promising therapeutic candidate against multiresistant pathogens, because they are able to kill microorganisms and have low toxicity of resistance cells. Hylin a1 (Hy-a1, IFGAILPLALGALKNLIK-NH2) is a peptide extracted from the skin secretion of the frog Hypsiboas albopunctatus, which displays antimicrobial and hemolytic activities. We report here structural studies of Hy-a1 using different techniques such as fluorescence, CD and NMR. Our data showed that Hy-a1 acquires a well defined amphipathic α-helix when interacting with a membrane-like environment. Furthermore, Hy-a1 presented different affinity when compared to membranes of zwitterionic or anionic lipid composition. Finally, we proposed a molecular interaction model of this peptide with micelles.

99 Active surveillance and containment of carbapenemase producing Enterobacteriaceae (CPE) in cystic fibrosis (CF) patients attending an Italian care centre

Objectives Carbapenemases, that hydrolyse most b-lactams, have emerged and spread worldwide. Currently are not many data of CPE in CF. The accesses to different hospitals, such as transplant centres, make these patients at high risk for transmission of CPE. The study aims to quantify and describe the CPE isolated from CF patients in a year about active surveillance. Methods During 2014, 147 rectal swabs were analyzed. The swabs were inoculated on McConkey agar plate with meropenem disk. The susceptibility testing was performed with automatic method (Phoenix). Carbapenemase were tested by disk diffusion synergy test. For molecular characterization was used GeneXpert. The fingerprinting of isolates were performed by Box-PCR. Results In ten samples we not evaluated the CPE because there was no bacterial growth. Three patients were colonized by CPE identified as E. cloacae. Clonal identity among strains was founded. The strains show a reduced susceptibility to carbapenems and the resistance to other b-lactams and aminoglycosides. The strains were susceptibility to fluoroquinolones, colistin and tigecycline. The molecular assay shows the presence of bla VIM gene. Conclusion The screening using culture methods has unsuitable for some CF patients while molecular method has more effective. Moreover the genotyping suggests a spread among patients. The CPE represents a danger for CF patients: this resistance may be transmitted to the multi-resistant pathogens that support CF pulmonary infection. Then an active surveillance, with an appropriate method of screening for CF patients, is needed to decrease and prevent the transmission of CPE.