The risk-benefit balance of resistance to ionophores in Enterococcus faecium and Enterococcus faecalis for ionophore coccidiostats in broiler chickens.

In recent years, publications and debate have emerged in the scientific literature that have linked the use of ionophore coccidiostats, which are themselves not medically important and not related to any therapeutic antibiotics used in human and animal medicine, to resistance development to medically important antibiotics in Enterococcus faecium and Enterococcus faecalis, isolated from broilers and broiler meat. This has been based on the discovery of genes, now named NarAB, that appear to result in elevated MICs of the ionophores narasin, salinomycin and maduramycin and that these are linked to genes responsible for resistance to antibiotics that may be clinically relevant in human medicine. This article will seek to review the most significant publications in this regard and will also examine national antimicrobial resistance surveillance programmes in Norway, Sweden, Denmark and the Netherlands, in order to further evaluate this concern. The conclusion of the review is that the risk that enterococci may pass from broilers to humans and that antimicrobial resistance gene transfer may occur is negligible, remains unquantified and is highly unlikely to be of significance to human health. Indeed, to date no human nosocomial infections have been linked to poultry sources. Concurrently a review of the possible impact of a policy that limits access for poultry farmers and poultry veterinarians to ionophore coccidiostats in broilers indicates predictable negative consequences with regard to antibiotic resistance of significance to animal welfare and to human health.

Survey of antimicrobial susceptibility of bacterial pathogens isolated from dogs and cats with respiratory tract infections in Europe: ComPath results.

AIMS: To present antimicrobial susceptibilities for bacteria from dogs and cats with respiratory tract infection (RTI) across Europe in 2013-2014 and compare with data from 2008-2010. METHODS AND RESULTS: Minimal inhibitory concentrations were determined for 464 isolates following Clinical and Laboratory Standards Institute standards using antibiotics approved for RTI treatment. Where possible, susceptibility was calculated using predominantly human-derived breakpoints whilst some antibiotics had no breakpoints. The main pathogen from dogs was Staphylococcus pseudintermedius which was > 90% susceptible to fluoroquinolones and oxacillin (92·5%; six isolates confirmed mecA-positive) and 53·8, 80·0 and 88·8% susceptible to tetracycline, penicillin and trimethoprim/sulfamethoxazole. Streptococci, Escherichia coli, Bordetella bronchiseptica, Staphylococcus aureus and Pseudomonas aeruginosa were also present in dog RTI. Streptococci were fully susceptible to penicillin, ampicillin and pradofloxacin. None were enrofloxacin-resistant but 31·4% had intermediate susceptibility. The least active agent against streptococci was tetracycline (51·4% susceptible). For E. coli, 90·9% were amoxicillin/clavulanic acid-susceptible; susceptibility to other compounds ranged from 63·6 to 81·8%. There are no breakpoints for B. bronchiseptica and Ps. aeruginosa. For Staph. aureus, penicillin susceptibility was low (34·8%); for other compounds 87·0-100%. The main RTI pathogen from cats was Pasteurella multocida, where only pradofloxacin has breakpoints (100% susceptible). Susceptibility of coagulase-negative staphylococci ranged from 66·7% (penicillin) to 97·2% (pradofloxacin). Streptococci from cats were 100% susceptible to all antibiotics except enrofloxacin and tetracycline (both 65·2% susceptible). CONCLUSIONS: Overall, antimicrobial resistance was low to medium in RTI in dogs and cats, although susceptibility varied widely among pathogens studied. SIGNIFICANCE AND IMPACT OF THE STUDY: Responsible use of antibiotics is crucial to maintain susceptibility and continued resistance monitoring is important to support this goal. These findings support the need for the setting of RTI-specific breakpoints for pathogens of dogs and cats.

Surveillance and monitoring of antimicrobial resistance and antibiotic consumption in humans and animals.

Surveillance and monitoring studies of antimicrobial resistance in bacteria of human and animal origin and antimicrobial consumption in humans and animals have been conducted in various countries throughout the world. In the veterinary field, in particular, programmes have been installed which target bacteria of zoonotic, foodborne and/or veterinary relevance. Each year, the European Surveillance of Veterinary Antimicrobial Consumption project summarises and evaluates antimicrobial consumption in ambulatory and hospital care in many European countries. In contrast, antimicrobial consumption data in veterinary medicine are available from only a few countries and the type of information that is collected or reported varies. To address this challenge, the European Surveillance of Veterinary Antimicrobial Consumption project was launched by the European Medicines Agency in September 2009 and has just published its first report. This comparison of the different studies for surveillance and monitoring of antimicrobial resistance and antimicrobial consumption in humans and animals shows the need to improve harmonisation.

Present and Future Surveillance of Antimicrobial Resistance in Animals: Principles and Practices.

There is broad consensus internationally that surveillance of the levels of antimicrobial resistance (AMR) occurring in various systems underpins strategies to address the issue. The key reasons for surveillance of resistance are to determine (i) the size of the problem, (ii) whether resistance is increasing, (iii) whether previously unknown types of resistance are emerging, (iv) whether a particular type of resistance is spreading, and (v) whether a particular type of resistance is associated with a particular outbreak. The implications of acquiring and utilizing this information need to be considered in the design of a surveillance system. AMR surveillance provides a foundation for assessing the burden of AMR and for providing the necessary evidence for developing efficient and effective control and prevention strategies. The codevelopment of AMR surveillance programs in humans and animals is essential, but there remain several key elements that make data comparisons between AMR monitoring programs, and between regions, difficult. Currently, AMR surveillance relies on uncomplicated in vitro antimicrobial susceptibility methods. However, the lack of harmonization across programs and the limitation of genetic information of AMR remain the major drawbacks of these phenotypic methods. The future of AMR surveillance is moving toward genotypic detection, and molecular analysis methods are expected to yield a wealth of information. However, the expectation that these molecular techniques will surpass phenotypic susceptibility testing in routine diagnosis and monitoring of AMR remains a distant reality, and phenotypic testing remains necessary in the detection of emerging resistant bacteria, new resistance mechanisms, and trends of AMR.

Gene transfer, gentamicin resistance and enterococci.

Enterococci are versatile pathogens by virtue of their ability to exhibit low-level intrinsic resistance to clinically useful antibiotics and their tolerance to adverse environmental conditions. In the last 20 years these pathogens have become progressively more difficult to treat because of their aptitude for acquiring antibiotic-resistance genes. Of increasing concern is the rapid dissemination of the AAC6'-APH2" bi-functional aminoglycoside modifying enzyme. This enzyme confers high-level resistance to gentamicin and all other related aminoglycosides with the exception of streptomycin. The gene conferring this phenotype has been associated with both narrow and broad host range plasmids, and has recently been found on conjugative transposons. The nature of these conjugative elements raises the possibility of the resistance gene spreading to other pathogenic bacteria.

Organisms associated with gram-negative folliculitis: in vitro growth in the presence of isotretinoin.

Isotretinoin has been found to be effective in the treatment of Gram-negative folliculitis. We investigated the direct in vitro antibacterial activity of isotretinoin against Gram-negative species. The concentrations of isotretinoin tested were two and ten times greater than the maximal levels attained in the sera of patients receiving oral isotretinoin. Regardless of the inoculum size, each organism tested grew as well in isotretinoin-containing media as it did in the control medium. These findings suggest that the efficacy of isotretinoin in patients with Gram-negative folliculitis is due to mechanisms other than direct antimicrobial action.

Pan-European resistance monitoring programmes encompassing food-borne bacteria and target pathogens of food-producing and companion animals.

Antimicrobial resistance is a concern both for animal and human health. Veterinary programmes monitoring resistance of animal and zoonotic pathogens are therefore essential. Various European countries have implemented national surveillance programmes, particularly for zoonotic and commensal bacteria, and the European Food Safety Authority (EFSA) is compiling the data. However, harmonisation is identified as a weakness and an essential need in order to compare data across countries. Comparisons of resistance monitoring data among national programmes are hampered by differences between programmes, such as sampling and testing methodology, and different epidemiological cut-off values or clinical breakpoints. Moreover, only very few valid data are available regarding target pathogens both of farm and companion animals. The European Animal Health Study Centre (CEESA) attempts to fill these gaps. The resistance monitoring programmes of CEESA have been a collaboration of veterinary pharmaceutical companies for over a decade and include two different projects: the European Antimicrobial Susceptibility Surveillance in Animals (EASSA) programme, which collects food-borne bacteria at slaughter from healthy animals, and the pathogen programmes that collect first-intention target pathogens from acutely diseased animals. The latter comprises three subprogrammes: VetPath; MycoPath; and ComPath. All CEESA projects include uniform sample collection and bacterial identification to species level in various European Union (EU) member states. A central laboratory conducts quantitative susceptibility testing to antimicrobial agents either important in human medicine or commonly used in veterinary medicine. This 'methodology harmonisation' allows easy comparisons among EU member states and makes the CEESA programmes invaluable to address food safety and antibiotic efficacy.

Quinupristin-dalfopristin resistance in Enterococcus faecium isolates from humans, farm animals, and grocery store meat in the United States.

Three hundred sixty-one quinupristin-dalfopristin (Q-D)-resistant Enterococcus faecium (QDREF) isolates were isolated from humans, turkeys, chickens, swine, dairy and beef cattle from farms, chicken carcasses, and ground pork from grocery stores in the United States from 1995 to 2003. These isolates were evaluated by pulsed-field gel electrophoresis (PFGE) to determine possible commonality between QDREF isolates from human and animal sources. PCR was performed to detect the streptogramin resistance genes vatD, vatE, and vgbA and the macrolide resistance gene ermB to determine the genetic mechanism of resistance in these isolates. QDREF from humans did not have PFGE patterns similar to those from animal sources. vatE was found in 35%, 26%, and 2% of QDREF isolates from turkeys, chickens, and humans, respectively, and was not found in QDREF isolates from other sources. ermB was commonly found in QDREF isolates from all sources. Known streptogramin resistance genes were absent in the majority of isolates, suggesting the presence of other, as-yet-undetermined, mechanisms of Q-D resistance.

Plasmid heterogeneity and identification of a Tn5281-like element in clinical isolates of high-level gentamicin-resistant Enterococcus faecium isolated in the UK.

Ten clinical isolates of high-level gentamicin-resistant (HLGR) Enterococcus faecium, collected from six hospitals throughout the UK, were studied to determine whether HLGR was attributed to widespread dissemination of a single plasmid or whether different plasmid types were implicated in the dissemination of this phenotype. HLGR was attributed to the presence of the AAC6'-APH2" bifunctional aminoglycoside modifying enzyme. The aac6'-aph2" gene was present on a 70 kb plasmid in all ten isolates. Conjugation studies indicated that the HLGR marker could transfer with varying frequency, with or without the associated 70 kb plasmid. Detailed molecular genetic analysis suggested that four of the isolates harboured a transposon similar to Tn5281, originally identified in Enterococcus faecalis strain HH22 isolated in the USA. The UK transposon, however, lacked the two symmetrically located HaeIII sites found in Tn5281. The six remaining isolates appeared to have a Tn5281-truncated structure in which the aac6'-aph2" gene is flanked by an IS256 element at the 5' end. Further studies with nine restriction endonucleases showed that the aac6'-aph2" gene was associated with two different plasmid types in E. faecium. Pulsed-field gel electrophoresis (PFGE) analysis identified three different patterns. The four E. faecium isolates harbouring the Tn5281-like structure were indistinguishable from each other, while the remaining six isolates exhibited two distinct PFGE patterns. This is the first study to indicate that there is heterogeneity among the plasmids that confer the HLGR phenotype in E. faecium isolates in the UK and to report on the presence of a transposon, similar to Tn5281, in E. faecium harbouring the aac6'-aph2" gene.

Multiple sclerosis and bullous pemphigoid.

3 patients with multiple sclerosis (MS) who developed severe widespread bullous pemphigoid (BP) are presented. MS preceded the presentation of BP by 13-23 years (mean 18 years). BP was confirmed histologically and immunopathologically. Upon successful therapy with steroids, no recurrence of BP was observed over a 3-5 year (mean 3.7 years) follow-up. Several abnormalities of the immune system have been reported in both diseases. It is interesting to speculate that amidst existing immunologic abnormalities in all 3 patients with MS, a specific event, immunologic or viral or both may have triggered the development of BP.

Nature of transposon-mediated high-level gentamicin resistance in Enterococcus faecalis isolated in the United Kingdom.

Forty-two high-level gentamicin-resistant (MIC > 1000 mg/L) strains of Enterococcus faecalis, isolated from diverse geographical locations throughout the UK between 1993 and 1995, were studied to identify the nature of the high-level gentamicin-resistant determinants and the possibility of these determinants being associated with a transposon. High-level gentamicin resistance was attributed to the synthesis of the bifunctional (AAC6'-APH2") aminoglycoside-modifying enzyme. The aac6'-aph2" gene, which was present on a 70 kb plasmid in all 42 isolates, could be transferred by conjugation in association with the 70 kb plasmid in 39 of the isolates studied. In three E. faecalis isolates, however, the high-level gentamicin resistance was transferable independent of the 70 kb plasmid, suggesting the presence of a conjugative transposon. Long-PCR studies showed that all 42 clinical isolates harboured a transposon similar to Tn5281, originally identified in E. faecalis strain HH22 isolated in the USA. Restriction endonuclease and Southern hybridization analysis of the UK transposon showed that it is closely related to the high-level gentamicin resistance-conferring transposon Tn5281. However, the UK transposon lacks the HaeIII site identified in Tn5281. Pulsed-field gel electrophoresis analysis identified seven different patterns. Further studies with nine restriction endonucleases showed that the aac6'-aph2" gene was associated with nine different plasmid types in E. faecalis.

Large acquired nevocytic nevi induced by the Koebner phenomenon.

A patient with characteristic clinical, histopathological, ultrastructural and family history of epidermolysis bullosa simplex (EBS) developed large acquired nevocytic nevi at the sites of some healing blisters. An isomorphic reaction may have initiated the development of these nevi. Such large acquired nevi should be considered in the differential diagnosis of large and giant congenital nevi which have the potential to evolve into malignant melanoma.

Tissue-specific autoantibodies and autoimmune disorders in vitiligo and alopecia areata: a retrospective study.

We retrospectively analyzed our laboratory reports of tissue-specific autoantibodies (TSA) in 38 patients with alopecia areata (AA) and 31 patients with vitiligo. These reports were based on standard indirect immunofluorescence (IF) procedures, employing monkey tissues as substrates. One or more TSA were detected in 39% of serum samples. Thyroid (microsomal and/or thyroglobulin) antibodies had the highest occurrence rate and, as compared with the normal population, were detected at a greater frequency in both vitiligo and AA. Over half (58%) of our patients with vitiligo had one or more detectable TSA, while only 28% of patients with AA had such antibodies. When compared with the normal population, the occurrence rate of TSA was higher in patients with vitiligo. The only remarkable finding in AA was a higher than normal occurrence rate of antithyroid antibodies.

Variation within the vat(E) allele of Enterococcus faecium isolates from retail poultry samples.

In a survey of retail meat samples, twelve quinupristin-dalfopristin-resistant (MICs, > or =4 mg/liter) Enterococcus faecium isolates that carried a vat(E) gene were recovered. DNA sequence comparison revealed five new variations in the vat(E) allele among 12 isolates, which were designated vat(E-4) through vat(E-8); two isolates had vat(E-1). There was no correlation between the number of base changes and the quinupristin-dalfopristin MIC.

Expression of efflux pump gene pmrA in fluoroquinolone-resistant and -susceptible clinical isolates of Streptococcus pneumoniae.

Thirty-four ciprofloxacin-resistant (MIC > or = 2 microg/ml) and 12 ciprofloxacin-susceptible clinical isolates of Streptococcus pneumoniae were divided into four groups based upon susceptibility to norfloxacin and the effect of reserpine (20 microg/ml). The quinolone-resistance-determining regions of parC, parE, gyrA, and gyrB of all ciprofloxacin-resistant clinical isolates were sequenced, and the activities of eight other fluoroquinolones, acriflavine, ethidium bromide, chloramphenicol, and tetracycline in the presence and absence of reserpine were determined. Despite a marked effect of reserpine upon the activity of norfloxacin, there were only a few isolates for which the activity of another fluoroquinolone was enhanced by reserpine. For most isolates the MICs of acriflavine and ethidium bromide were lowered in the presence of reserpine despite the lack of effect of this efflux pump inhibitor on fluoroquinolone activity. The strains that were most resistant to the fluoroquinolones were predominantly those with mutations in three genes. Expression of the gene encoding the efflux pump PmrA was examined by Northern blotting (quantified by quantitative competitive reverse transcriptase PCR) and compared with that of S. pneumoniae R6 and R6N. Within each group there were isolates that had high-, medium-, and low-level expression of this gene; however, increased expression was not exclusively associated with those isolates with a phenotype suggestive of an efflux mutant. These data suggest that there is another reserpine-sensitive efflux pump in S. pneumoniae that extrudes ethidium bromide and acriflavine but not fluoroquinolones.