Impaired stress-coping and fear extinction and abnormal corticolimbic morphology in serotonin transporter knock-out mice

A lesser-expressing form of the human 5-HT transporter (5-HTT) gene has been associated with increased fear and anxiety and vulnerability to the effects of stress. These phenotypic abnormalities are linked to functional and anatomical disturbances in a neural pathway connecting the prefrontal cortex (PFC) and amygdala. Likewise, rodent and nonhuman primate studies indicate a major role for PFC and amygdala in the mediation of fear- and stress-related behaviors. We used a 5-HTT knock-out (KO) mouse to examine the effects of genetically driven loss of 5-HTT function for the following: (1) depression-related behavior in response to repeated stress, and pavlovian fear conditioning, extinction, and extinction recall; and (2) dendritic morphology and spine density of Golgi-stained pyramidal neurons in the infralimbic cortex (IL) and the basolateral amygdala (BLA). 5-HTT KO mice exhibited increased depressive-like immobility after repeated exposure to forced swim stress, compared with wild-type (WT) controls. Whereas fear conditioning and fear extinction was normal, 5-HTT KO mice exhibited a significant deficit in extinction recall. The apical dendritic branches of IL pyramidal neurons in 5-HTT KO mice were significantly increased in length relative to WT mice. Pyramidal neurons in BLA had normal dendritic morphology but significantly greater spine density in 5-HT KO mice compared with WT mice. Together, the present findings demonstrate a specific phenotypic profile of fear- and stress-related deficits in 5-HTT KO mice, accompanied by morphological abnormalities in two key neural loci. These data provide insight into the behavioral sequelae of loss of 5-HTT gene function and identify potential neural substrates underlying these phenotypes.

Community-associated meticillin-resistant Staphylococcus aureus: nosocomial transmission in a neonatal unit

Community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen, increasingly reported worldwide to cause infections in individuals without classical risk factors for acquiring healthcare-associated MRSA (HA-MRSA). This report describes the first documented transmission of CA-MRSA in a healthcare setting in the UK, involving four babies and a member of staff in a neonatal unit. Detailed microbiological characterization of the isolates revealed that they represented a single clone with the following characteristics: multi-locus sequence type (MLST) 1; staphylococcal cassette chromosome mec (SCCmec) type IVa; protein A (spa) type t127; agr group 3, and encoding enterotoxins A and H. The Panton-Valentine leukocidin genes were not detected. The CA-MRSA strain appeared to be circulating alongside several subtypes of epidemic MRSA-15, the most prevalent HA-MRSA in the UK. A combination of infection control measures contained the outbreak. This report highlights the changing epidemiology of MRSA in the UK, and emphasizes the need for healthcare personnel to be alert to the fact that CA-MRSA can occur not only in the community but also in the healthcare setting.

Galanin as a modulator of anxiety and depression and a therapeutic target for affective disease

Galanin is a 29 amino-acid (30 in humans) neuropeptide with a close functional relationship with neurotransmitter systems implicated in the pathophysiology and treatment of depression and anxiety disorders. In rodent models of depression-related behavior, treatment with galanin or compounds with agonist actions at galanin receptors has been shown to affect depression-related behaviors and the behavioral and neurochemical effects of antidepressants. Treatment with clinically efficacious antidepressants alters galanin and galanin receptor gene expression in rodents. Rodent anxiety-like behaviors appear to be modulated by galanin in a complex manner, with studies showing either increases, decreases and no effects of galanin treatments and galanin mutations on anxiety-like behavior in various tasks. One concept to emerge from this literature is that galanin recruitment during extreme behavioral and physiological provocations such as stress and opiate withdrawal may serve to attenuate negative emotional states caused by noradrenergic hyperactivation. The specific galanin receptor subtypes mediating the anxiety- and depression-related effects of galanin remains to be determined, with evidence supporting a possible contribution of GalR1, GalR2 and GalR3. While our understanding of the role of galanin as a modulator of emotion remains at an early stage, recent progress in this rapidly evolving field raise possibility of that galanin may represent a target for the development of novel antidepressant and anxiolytic drug treatments.

High interlaboratory reproducibility of DNA sequence-based typing of bacteria in a multicenter study

Current DNA amplification-based typing methods for bacterial pathogens often lack interlaboratory reproducibility. In this international study, DNA sequence-based typing of the Staphylococcus aureus protein A gene (spa, 110 to 422 bp) showed 100% intra- and interlaboratory reproducibility without extensive harmonization of protocols for 30 blind-coded S. aureus DNA samples sent to 10 laboratories. Specialized software for automated sequence analysis ensured a common typing nomenclature.

Galanin: A Novel Therapeutic Target for Depression, Anxiety Disorders and Drug Addiction?

Galanin is a neuropeptide synthesized in many neuronal types including brainstem norepinephrine-producing cells of the locus coeruleus and the serotonin-producing neurons of the dorsal raphe nucleus. Galanin inhibits the firing of rodent norepinephrine, serotonin and dopamine neurons and reduces release of these neurotransmitters in forebrain target regions. The distribution of galanin and its receptors and its actions on monoamine signaling has fostered interest in this neuropeptide in the field of behavioral pharmacology and the potential role of galanin in the pathophysiology of neurological diseases such as Alzheimer's disease, epilepsy, stroke, and in psychiatric disorders such as anxiety, depression, and drug addiction, particularly withdrawal. In rodent models, expression of galanin in brain is altered by various stressors, while administration of galanin can modulate anxiety-like responses to stress. Emerging evidence further supports a role for galanin in the mediation of depression-related behaviors in rodents. Recently, galanin agonists have been shown to decrease behavioral signs of opiate withdrawal, which are thought to result from hyperactivation of brain stress pathways. Studies using genetically modified mice suggest that galanin normally plays a protective role against opiate reinforcement and withdrawal. The present article reviews current evidence on a potential role for galanin in modulating stress-related neural pathways and behaviors, and speculates on the therapeutic potential of targeting this galanin system for emotional disorders and opiate addiction.

Delayed leech-borne infection with Aeromonas hydrophilia in escharotic flap wound

Medicinal leeches (Hirudo medicinalis) are commonly used in plastic surgery for the salvage of congested flaps and replanted parts compromised by venous congestion. Infection associated with leech therapy is a documented complication of leech application, with reported incidences ranging from 2.4 to 20% [De Chalain TM. Exploring the use of the medicinal leech: a clinical risk-benefit analysis. J Reconstr Microsurg 1996;12(3):165-72.1]. We describe a case of delayed leech-borne infection, from the escharotic portion of a latissimus dorsi flap, which developed several days after stopping leech therapy for venous congestion in a reconstructed breast.

Insertion mutation at the C-terminus of the serotonin transporter disrupts brain serotonin function and emotion-related behaviors in mice

The 5-hydroxytryptamine transporter (5-HTT) regulates 5-hydroxytryptamine (5-HT) neurotransmission by removing 5-HT from the synaptic cleft. Emerging evidence from clinical and genetic studies implicates the 5-HTT in various neuropsychiatric conditions, including anxiety and depression. Here we report that a 5-HTT null mutant mouse line was generated by gene trapping that disrupted the sequence encoding the C-terminus of 5-HTT. This mutation resulted in significant reduction of 5-HTT mRNA and loss of 5-HTT protein. Brain levels of 5-HT and its major metabolite, 5-hydroxyindoleacetic acid, were markedly decreased in C-terminus 5-HTT -/- mice, while 5-HT uptake or 5-HT content in platelets was absent. Behavioral phenotyping showed that C-terminus 5-HTT -/- mice were normal on a screen for gross behavioral, neurological, and sensory functions. In the tail suspension test for depression-related behavior, C-terminus 5-HTT -/- mice showed increased immobility relative to their +/+ controls. By comparison, a previously generated line of 5-HTT -/- mice lacking exon 2, encoding the N-terminus of the 5-HTT, showed abnormally high immobility in response to repeated, but not acute, exposure to the tail suspension test. In a novel, brightly-lit open field, both C-terminus 5-HTT -/- mice and N-terminus 5-HTT -/- mice displayed decreased center time and reduced locomotor activity compared with their +/+ controls. Both mutant lines buried significantly fewer marbles than their +/+ controls in the marble burying test. These findings further demonstrate the neurobiological functions of the 5-HTT and add to a growing literature linking genetic variation in 5-HTT function with emotional abnormalities.

Interventions to improve antibiotic prescribing practices for hospital inpatients

BACKGROUND

Up to 50% of antibiotic usage in hospitals is inappropriate. In hospitals infections caused by antibiotic-resistant bacteria are associated with higher mortality, morbidity and prolonged hospital stay compared with infections caused by antibiotic-susceptible bacteria. Clostridium difficile associated diarrhoea (CDAD) is a hospital acquired infection that is caused by antibiotic prescribing.

OBJECTIVES

To estimate the effectiveness of professional interventions that alone, or in combination, are effective in promoting prudent antibiotic prescribing to hospital inpatients, to evaluate the impact of these interventions on reducing the incidence of antimicrobial resistant pathogens or CDAD and their impact on clinical outcome.

SEARCH STRATEGY

We searched the Cochrane Effective Practice and Organisation of Care (EPOC) specialized register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE from 1980 to November 2003. Additional studies were obtained from the bibliographies of retrieved articles

SELECTION CRITERIA

We included all randomised and controlled clinical trials (RCT/CCT), controlled before and after studies (CBA) and interrupted time series (ITS) studies of antibiotic prescribing to hospital inpatients. Interventions included any professional or structural interventions as defined by EPOC.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data and assessed quality.

MAIN RESULTS

Sixty six studies were included and 51 (77%) showed a significant improvement in at least one outcome. Six interventions only aimed to increase treatment, 57 interventions aimed to decrease treatment and three interventions aimed to both increase and decrease treatment. The intervention target was the decision to prescribe antibiotics (one study), timing of first dose (six studies), the regimen (drug, dosing interval etc, 61 studies) or the duration of treatment (10 studies); 12 studies had more than one target. Of the six interventions that aimed to increase treatment, five reported a significant improvement in drug outcomes and one a significant improvement in clinical outcome. Of the 60 interventions that aimed to decrease treatment 47 reported drug outcomes of which 38 (81%) significantly improved, 16 reported microbiological outcomes of which 12 (75%) significantly improved and nine reported clinical outcomes of which two (22%) significantly deteriorated and 3 (33%) significantly improved. Five studies aimed to reduce CDAD. Three showed a significant reduction in CDAD. Due to differences in study design and duration of follow up it was only possible to perform meta-regression on a few studies.

AUTHORS' CONCLUSIONS

The results show that interventions to improve antibiotic prescribing to hospital inpatients are successful, and can reduce antimicrobial resistance or hospital acquired infections.

Clinician-led surgical site infection surveillance of orthopaedic procedures: a UK multi-centre pilot study

The UK Department of Health established the Healthcare-associated Infection (HAI) Surveillance Steering Group in 2000 to develop a strategy for implementing a national programme for HAI surveillance in National Health Service trusts. A subgroup of this committee examined the surveillance of surgical site infections following orthopaedic surgery. This group oversaw a pilot scheme that was set up in 12 hospitals around the UK to explore the feasibility of implementing a system of surveillance that engaged clinical staff in its operation, provided a process for continuous data collection and could be maintained as part of routine hospital operation over time. A minimum data set was established by the subgroup, and Centers for Disease Control and Prevention (CDC) definitions of infection were used. By March 2003, the surveillance had been undertaken continuously in 11 sites for one to two years, depending on the date of implementation. Only one hospital had ceased data collection. The information was collected mainly by clinical staff, with support and co-ordination usually provided by infection control teams. Data on more than 5400 procedures were available for analysis for four core procedures: arthroplasty of the hip and knee; hemi-arthroplasty of the hip; and internal fixation of trochanteric fractures of the femur. The data set permitted the calculation of risk-adjusted rates, allowing comparisons between hospitals and within a hospital over time. The methodology enhanced clinical ownership of the surveillance process, re-inforced infection control as the responsibility of all staff, and provided timely feedback and local data analysis. The use of CDC definitions permitted international comparisons of the data.

Staphylococcus aureus isolates carrying Panton-Valentine leucocidin genes in England and Wales: frequency, characterization, and association with clinical disease

Staphylococcus aureus isolates carrying the genes that encode for Panton-Valentine leucocidin (PVL), a highly potent toxin, have been responsible for recent outbreaks of severe invasive disease in previously healthy children and adults in the United States of America and Europe. To determine the frequency of PVL-positive isolates sent to the Staphylococcus Reference Unit (United Kingdom) for epidemiological purposes, we tested 515 isolates of S. aureus, and 8 (1.6%) were positive for the PVL locus. A further 470 isolates were selected to explore the association of PVL-positive S. aureus with clinical disease. Of these, 23 (4.9%) were PVL positive and most were associated with skin and soft tissue infections (especially abscesses). The PVL genes were also detected in isolates responsible for community-acquired pneumonia, burn infections, bacteremia, and scalded skin syndrome. Genotyping by pulsed-field gel electrophoresis and multilocus sequence typing revealed that the PVL-positive isolates were from diverse genetic backgrounds, although one prevalent clone of 12 geographically dispersed methicillin-resistant S. aureus (MRSA) isolates was identified (ST80). All 12 isolates were stapylococcal cassette chromosome mec type IVc, had an agr3 allele, and shared a common toxin gene profile (sea-see, seg-sej, eta, etb, and tst negative but etd positive). ST80 strains with similar genetic characteristics have been responsible for community-acquired infections in France and Switzerland. The remaining PVL-positive isolates were mostly methicillin-sensitive S. aureus and belonged to 12 different sequence types, including ST22 and ST30, which are closely related to the most prevalent MRSA clones in United Kingdom hospitals, EMRSA-15 and EMRSA-16, respectively.

Methicillin-resistant Staphylococcus aureus in orthopaedic surgery

We prospectively studied the incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation and infection, the patterns and types of operation associated with MRSA acquisition in an orthopaedic and trauma unit in London, UK. Over the 12-month study period from January to December 2000, we found that 1.6% of the total admission was diagnosed to be either MRSA infected or colonised, with an average of three new MRSA cases detected per month. A significant proportion of patients (23%) were diagnosed within the first 48h of admission. Both hip joint surgery, especially emergency procedures for femoral neck fractures, and the presence of a wound presented higher risk of infection. The Intensive Care Unit (ICU) did not appear to be a significant source for intra-hospital dissemination among the orthopaedic patients. MRSA infection or colonisation contributed to an increased length of hospital stay; 88 days compared to 11 days on average for non-MRSA patients; 41% of the positive patients still carried MRSA on discharge. Our data show the importance of diagnosing MRSA in orthopaedic surgery and emphasises that understanding its epidemiology will be crucial to secure a decrease in the incidence of MRSA. Hand hygiene, patient screening, careful surveillance of infections and the prompt implementation of isolation policies, are essential components of control.

Abnormal anxiety-related behavior in serotonin transporter null mutant mice: the influence of genetic background

Serotonin transporter (5-HTT) null mutant mice provide a model system to study the role genetic variation in the 5-HTT plays in the regulation of emotion. Anxiety-like behaviors were assessed in 5-HTT null mutants with the mutation placed on either a B6 congenic or a 129S6 congenic background. Replicating previous findings, B6 congenic 5-HTT null mutants exhibited increased anxiety-like behavior and reduced exploratory locomotion on the light <--> dark exploration and elevated plus-maze tests. In contrast, 129S6 congenic 5-HTT null mutant mice showed no phenotypic abnormalities on either test. 5-HTT null mutants on the 129S6 background showed reduced 5-HT(1A) receptor binding (as measured by quantitative autoradiography) and reduced 5-HT(1A) receptor function (as measured by 8-OH-DPAT-induced hypothermia). These data confirm that the 5-HTT null mutation produced alterations in brain 5-HT function in mice on the 129S6 background, thereby discounting the possibility that the absence of an abnormal anxiety-like phenotype in these mice was due to a suppression of the mutation by 129 modifier genes. Anxiety-like behaviors in the light <--> dark exploration and elevated plus-maze tests were significantly higher in 129S6 congenic +/+ mice as compared to B6 congenic +/+ mice. This suggests that high baseline anxiety-like behavior in the 129S6 strain might have precluded detection of the anxiety-like effects of the 5-HTT null mutation on this background. Present findings provide further evidence linking genetic variation in the 5-HTT to abnormalities in mood and anxiety. Furthermore, these data highlight the utility of conducting behavioral phenotyping of mutant mice on multiple genetic backgrounds.

Experimental gene interaction studies with SERT mutant mice as models for human polygenic and epistatic traits and disorders

Current evidence indicates that virtually all neuropsychiatric disorders, like many other common medical disorders, are genetically complex, with combined influences from multiple interacting genes, as well as from the environment. However, additive or epistatic gene interactions have proved quite difficult to detect and evaluate in human studies. Mouse phenotypes, including behaviors and drug responses, can provide relevant models for human disorders. Studies of gene-gene interactions in mice could thus help efforts to understand the molecular genetic bases of complex human disorders. The serotonin transporter (SERT, 5-HTT, SLC6A4) provides a relevant model for studying such interactions for several reasons: human variants in SERT have been associated with several neuropsychiatric and other medical disorders and quantitative traits; SERT blockers are effective treatments for a number of neuropsychiatric disorders; there is a good initial understanding of the phenotypic features of heterozygous and homozygous SERT knockout mice; and there is an expanding understanding of the interactions between variations in SERT expression and variations in the expression of a number of other genes of interest for neuropsychiatry and neuropharmacology. This paper provides examples of experimentally-obtained interactions between quantitative variations in SERT gene expression and variations in the expression of five other mouse genes: DAT, NET, MAOA, 5-HT(1B) and BDNF. In humans, all six of these genes possess polymorphisms that have been independently investigated as candidates for neuropsychiatric and other disorders in a total of > 500 reports. In the experimental studies in mice reviewed here, gene-gene interactions resulted in either synergistic, antagonistic (including 'rescue' or 'complementation') or more complex, quantitative alterations. These were identified in comparisons of the behavioral, physiological and neurochemical phenotypes of wildtype mice vs. mice with single allele or single gene targeted disruptions and mice with partial or complete disruptions of multiple genes. Several of the descriptive phenotypes could be best understood on the basis of intermediate, quantitative alterations such as brain serotonin differences. We discuss the ways in which these interactions could provide models for studies of gene-gene interactions in complex human neuropsychiatric and other disorders to which SERT may contribute, including developmental disorders, obesity, polysubstance abuse and others.

Preoperative skin antiseptics for preventing surgical wound infections after clean surgery

BACKGROUND

Approximately 15% of elective surgery patients and 30% of patients receiving contaminated or dirty surgery are estimated to develop post-operative wound infections. The costs of surgical wound infection can be considerable in financial as well as social terms. Preoperative skin antisepsis is performed to reduce the risk of post-operative wound infections by removing soil and transient organisms from the skin. Antiseptics are thought to be both toxic to bacteria and aid their mechanical removal. The effectiveness of preoperative skin preparation is thought to be dependent on both the antiseptic used and the method of application, however it is unclear whether preoperative skin antisepsis actually reduces post-operative wound infection and if so which antiseptic is most effective.

OBJECTIVES

To determine whether preoperative skin antisepsis reduces post-operative surgical wound infection.

SEARCH STRATEGY

We searched the Cochrane Wounds Group Specialised Trials Register and the Cochrane Central Register of Controlled Trials in April 2004. In addition we handsearched journals, conference proceedings and bibliographies.

SELECTION CRITERIA

Randomised controlled trials evaluating the use of preoperative skin antiseptics applied immediately prior to incision in clean surgery. There were no restrictions based on language, date or publication status.

DATA COLLECTION AND ANALYSIS

Three reviewers independently undertook data extraction and assessment of study quality. Pooling was inappropriate and trials are discussed in a narrative review.

MAIN RESULTS

We identified six eligible RCTs evaluating preoperative antiseptics. There was significant heterogeneity in the comparisons and the results could not be pooled. In one study, infection rates were significantly lower when skin was prepared using chlorhexidine compared with iodine. There was no evidence of a benefit in four trials associated with the use of iodophor impregnated drapes.

REVIEWERS' CONCLUSIONS

There is insufficient research examining the effects of preoperative skin antiseptics to allow conclusions to be drawn regarding their effects on post-operative surgical wound infections. Further research is needed.

Multidisciplinary antimicrobial management and the role of the infectious diseases pharmacist--a UK perspective

Improved clinical outcome, patient safety, cost savings and a reduction in the burden of antimicrobial resistance are outcomes associated with optimizing antimicrobial use. Despite this, the misuse of antimicrobials in the hospital setting remains a huge problem. The development of antimicrobial management teams and the promotion of the role of the clinical pharmacist in antimicrobial prescribing are recommended strategies for improving prescribing practice. It is recognized that there is a lack of published evidence-based research looking at the effects of antimicrobial control programmes and there is a need for more data. In the UK, the role of the hospital pharmacist in promoting responsible antimicrobial prescribing has been largely undervalued and needs to be encouraged and formalized in line with current directives. Managerial structures within hospitals need to endorse multidisciplinary antimicrobial management schemes with appropriate authoritative, administrative and information technology support.

Galanin peptide levels in hippocampus and cortex of galanin-overexpressing transgenic mice evaluated for cognitive performance

Galanin-overexpressing transgenic mice (GAL-tg) generated on a dopamine beta-hydroxylase promoter were previously shown to express high levels of galanin mRNA in the locus coeruleus, and to perform poorly on challenging cognitive tasks. The present study employed radioimmunoassay to quantitate the level of galanin peptide overexpression in two brain regions relevant to learning and memory, the hippocampus and cerebral cortex. Approximately 4-fold higher levels of galanin were detected in the hippocampus of GAL-tg as compared to WT. Approximately 10-fold higher levels of galanin were detected in the frontal cortex of GAL-tg as compared to WT. A second cohort of GAL-tg and WT again showed high levels of galanin overexpression in GAL-tg as compared to WT in both brain regions. Correlation analyses were conducted between galanin peptide concentrations and behavioral scores on four learning and memory tasks: the Morris water maze, social transmission of food preference, standard delay fear conditioning, and trace fear conditioning. While some significant correlations were detected, neither hippocampal nor cortical galanin levels in the two cohorts of GAL-tg consistently correlated with performance across these diverse cognitive tasks. Several interpretations of these findings are discussed, including the possibility that a threshold level of galanin overexpression is sufficient to impair performance on learning and memory tasks in mice.