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A rise in antimicrobial resistance, seen especially since 2000, is in part caused by indiscriminate antimicrobial use. Varied types of persuasive interventions aimed to optimize antimicrobial use have been tried with varying success. Our review seeks to identify and assess factors associated with the successful implementation of persuasive interventions. We searched five databases (MEDLINE, EMBASE, The Cochrane Library, PsycINFO, and ERIC) to identify critical studies published between 2000 and December 2018 of interventions employing audit and feedback, education through meetings, academic detailing, reminders, and patient, family, or public education. Outcome measures of interest were any means to measure antimicrobial use. We included 26 articles in our analysis. Seventeen examined multimodal interventions and the most common was audit and feedback and meeting (four studies). Nine examined single interventions and the most common was audit and feedback (five studies). Our findings inform four evidence-based strategies to enable healthcare administrators, clinicians, and researchers to make informed choices when planning and designing an antimicrobial stewardship program: (1) implement a combination of persuasive interventions from both groups: audit and feedback, academic detailing, or patient, family, or provider education; and meeting or reminders, (2) design interventions that last one year or longer; post-intervention, assess the intervention’s long-term effects for at least another one year, (3) conduct quality improvement projects examining persuasive interventions if the prescribing database provides adequate diagnosis information, and most importantly, (4) make patient, family, or provider education an integral component of multimodal intervention.

Background Hand hygiene (HH) in health care facilities is a key component to reduce pathogen transmission and nosocomial infections. However, most HH interventions (HHI) have not been sustainable. Aims This review aims to provide a comprehensive summary of recently published evidence-based HHI designed to improve HH compliance (HHC) that will enable health care providers to make informed choices when allocating limited resources to improve HHC and patient safety. Methods The Medline electronic database (using PubMed) was used to identify relevant studies. English language articles that included hand hygiene interventions and related terms combined with health care environments or related terms were included. Results Seventy-three studies that met the inclusion criteria were summarized. Interventions were categorized as improving awareness with education, facility design, and planning, unit-level protocols and procedures, hospital-wide programs, and multimodal interventions. Past successful HHIs may not be as effective when applied to other health care environments. HH education should be interactive and engaging. Electronic monitoring and reminders should be implemented in phases to ensure cost-effectiveness. To create hospitalwide programs that engage end users, policy makers should draw expertise from interdisciplinary fields. Before implementing the various components of multimodal interventions, health care practitioners should identify and examine HH difficulties unique to their organizations. Conclusions Future research should seek to achieve the following: replicate successful HHI in other health care environments, develop reliable HHC monitoring tools, understand caregiver-patient-family interactions, examine ways (eg, hospital leadership, financial support, and strategies from public health and infection prevention initiatives) to sustain HHC, and use simulated lab environments to refine study designs.

Background A steady rise in the use of cardiovascular implantable electronic devices (CIEDs), particularly in the elderly, has led to an increase in device-related infections. Although often studied and reported as a single entity, these complications in fact comprise a heterogeneous group. Specific subgroups may be associated with distinct mortality risks. Methods Medical records of all patients who underwent device extraction for CIED-related infection at a single tertiary referral center between 1991 and 2007 were reviewed. Infections were divided into four subgroups: primary pocket site infection (PPSI), pocket site infection with bacteremia, primary/isolated bacteremia (PIB), and device-related infective endocarditis (DRIE). Clinical presentation, laboratory data, and mortality rates were obtained by chart review and by querying the Social Security Death Index. Results A total of 387 cases were analyzed. The overall in-hospital and 1-year all-cause mortality rates were 7.2% and 25.3%, respectively. Patients with PIB or DRIE had significantly higher mortality rates (hazard ratio [HR] 2.3; 95% confidence interval [CI] 1.2–4.6 and HR 2.5; 95% CI 1.6–4.1, respectively) when compared with patients in the PPSI group. Patients who did not receive a new device during the initial admission also had a higher 1-year mortality rate compared to those who did (HR 2.7; 95% CI 1.8–4.1). Conclusions Our patients with CIED-related infections requiring extraction/hospitalization had a significant mortality risk. Presence of pocket site infection carried a more favorable prognosis, regardless of the presence of bacteremia. Early detection and prevention of CIED-related infections with PIB (i.e., no pocket site involvement), especially for high-risk populations, is needed.

Diarrhea is the most common health issue affecting travelers to destinations across the world. This paper reviews the options for initial treatment of acute traveler’s diarrhea (TD). Its prevention, including but not limited to vaccines and safe travel and eating habits, is an important consideration but is beyond the scope of this paper. Treatment of TD has three arms: volume repletion, antibiotics, and antimotility/antisecretory agents. Patients should be advised to continue a diet that they can tolerate and maintain adequate fluid intake. In most cases, neither oral rehydration therapy nor dietary restrictions are likely to provide significant benefit. As yet, there is no evidence to support probiotic use for treatment of this type of diarrhea. Given that bacteria are the most frequent cause of TD, adult patients with moderate to severe disease should be treated empirically with a short course of antibiotics. In many instances, these will be prescribed pre-travel with instructions for proper usage when typical symptoms occur while abroad. However, such travelers should be advised to see a physician or seek emergency treatment if symptoms are severe or persist beyond 3 days. Antibiotic selection must take into account the epidemiology of resistant enteric pathogens. Fluoroquinolones are usually effective, although resistance of Campylobacter to this class of drugs in South and Southeast Asia warrants azithromycin as first-line empiric therapy in travelers to those regions. One day of therapy is often sufficient but can be extended to 3 days. Rifaximin is an alternative in non-invasive disease only. The antimotility agent loperamide is safe and effective and should be considered as adjunctive therapy in most cases of TD and can similarly be prescribed pre-travel. In non-pregnant adults, bismuth subsalicylate can also provide some symptomatic relief. Where available, racecadotril may be a safe alternative in both adults and children, although never specifically studied in TD. In cases of severe symptoms, or those lasting longer than 3 days, the patient should be evaluated for non-bacterial etiologies as well as possible Clostridium difficile infection. Certain travelers are more vulnerable to severe complications related to TD. Children, particularly infants, may need more aggressive fluid resuscitation with oral rehydration therapy. Several of the antidiarrheal agents must be avoided. Elderly patients and those with impaired cardiovascular reserve or immune-deficient states are more prone to complications as well. Treatment recommendations also differ for pregnant women. We generally advise adult non-pregnant travelers to follow smart eating and drinking practices and to bring a supply of bismuth subsalicylate and loperamide. We also prescribe an empiric antibiotic course (ciprofloxacin or azithromycin for up to 3 days) that is to be used for moderate to severe cases of TD.

Optimal antibiotic management of patients with osteomyelitis remains a challenge for many clinicians. Although image-guided bone biopsy (IGB) remains the gold standard, its role in confirming diagnosis and guiding antibiotic management is not clear in patients with non-vertebral osteomyelitis.To determine the diagnostic yield of IGB and its impact on antibiotic management in non-vertebral osteomyelitis.Retrospective cohort study.Urban academic medical center.Patients admitted for non-vertebral osteomyelitis who underwent image-guided bone biopsy.Primary outcomes were microbiologic and histopathological results. We evaluated the impact of IGB on clinician-initiated changes in antibiotic regimen before and after biopsy.We evaluated 203 bone biopsies in 185 patients with clinical suspicion of osteomyelitis. 79% of patient received antibiotics prior to biopsy. Bone cultures were positive in 28% and histopathology confirmed osteomyelitis in 29%, but concordance was poor. Furthermore, clinical suspicion of infection was much higher, given that 68% received empiric antibiotics. Leukocytosis was significantly associated with positive cultures in multivariate analysis. There was no statistically significant correlation between antibiotic management and bone culture results. When culture yielded an organism, empiric regimens were kept the same, broadened or narrowed with equal frequency; targeted regimens were chosen only in 4 cases. Despite negative cultures in 98/138 cases having received empiric treatment, antibiotics were discontinued in only 8 cases. Even when empiric treatment was not given, negative cultures did not dissuade clinicians from eventual antibiotic use in a significant number of cases (17/48). In 46/71 patients whose final regimen included vancomycin, there was no evidence of current or past infection with MRSA.In patients with non-vertebral osteomyelitis, the diagnostic yield of image-guided bone biopsy is low, and clinicians frequently make decisions regarding antibiotic management that are not aligned with culture results.

Local palmitoylation machinery has an instructive role in creating activity-responsive PSD-95 nanodomains, which contribute to postsynaptic density (re)organization., Distinct PSD-95 clusters are primary landmarks of postsynaptic densities (PSDs), which are specialized membrane regions for synapses. However, the mechanism that defines the locations of PSD-95 clusters and whether or how they are reorganized inside individual dendritic spines remains controversial. Because palmitoylation regulates PSD-95 membrane targeting, we combined a conformation-specific recombinant antibody against palmitoylated PSD-95 with live-cell super-resolution imaging and discovered subsynaptic nanodomains composed of palmitoylated PSD-95 that serve as elementary units of the PSD. PSD-95 in nanodomains underwent continuous de/repalmitoylation cycles driven by local palmitoylating activity, ensuring the maintenance of compartmentalized PSD-95 clusters within individual spines. Plasma membrane targeting of DHHC2 palmitoyltransferase rapidly recruited PSD-95 to the plasma membrane and proved essential for postsynaptic nanodomain formation. Furthermore, changes in synaptic activity rapidly reorganized PSD-95 nano-architecture through plasma membrane–inserted DHHC2. Thus, the first genetically encoded antibody sensitive to palmitoylation reveals an instructive role of local palmitoylation machinery in creating activity-responsive PSD-95 nanodomains, contributing to the PSD (re)organization.

International audience; Dyggve-Melchior-Clausen dysplasia (DMC) is a rare inherited dwarfism with severe mental retardation due to mutations in the DYM gene which encodes Dymeclin, a 669-amino acid protein of yet unknown function. Despite a high conservation across species and several predicted transmembrane domains, Dymeclin could not be ascribed to any family of proteins. Here we show, using in situ hybridization, that DYM is widely expressed in human embryos, especially in the cortex, the hippocampus and the cerebellum. Both the endogenous and the recombinant protein fused to green fluorescent protein co-localized with Golgi apparatus markers. Electron microscopy revealed that Dymeclin associates with the Golgi apparatus and with transitional vesicles of the reticulum-Golgi interface. Moreover, permeabilization assays revealed that Dymeclin is not a transmembrane but a peripheral protein of the Golgi apparatus as it can be completely released from the Golgi after permeabilization of the plasma membrane. Time lapse confocal microscopy experiments on living cells further showed that the protein shuttles between the cytosol and the Golgi apparatus in a highly dynamic manner and recognizes specifically a subset of mature Golgi membranes. Finally, we found that DYM mutations associated with DMC result in mis-localization and subsequent degradation of Dymeclin. These data indicate that DMC results from a loss-of-function of Dymeclin, a novel peripheral membrane protein which shuttles rapidly between the cytosol and mature Golgi membranes and point out a role of Dymeclin in cellular trafficking.

Apoptosis has been found to help in the defence against pathogens. Infection with the obligate intracellular parasite Toxoplasma gondii is known to trigger host-cell apoptosis. When using a T. gondii-infected macrophage cell line, J774A.1, treatment with IFN-gamma significantly enhanced apoptosis in noninfected bystander cells while parasitized cells became relatively resistant. Infection and IFN-gamma treatment activated the expression of inducible nitric oxide synthase (iNOS), and the production of nitric oxide (NO) and treatment of cells with an iNOS inhibitor, N(G)-monomethlyl-L-arginine acetate (L-NMMA) reduced the apoptosis frequency. However, the reversal was only partial suggesting that not only NO, but also other, as of yet, unknown factors are induced. Finally, we studied the effect in vivo by infecting mice with either a virulent or an avirulent strain. Challenge with the virulent strain lead to a higher parasite burden, induced host-cell apoptosis in peritoneal cells, and produced higher levels of IFN-gamma and NO. Moreover, treatment of mice with a NO synthase inhibitor, aminoguanidine, partially inhibited the host-cell apoptosis induced by the parasite infection. Altogether, our findings indicate that apoptosis in bystander host cells is due to the secretion of NO and other soluble factors released by parasite-infected cells.

A steady rise in the use of cardiovascular implantable electronic devices (CIEDs), particularly in the elderly, has led to an increase in device-related infections. Although often studied and reported as a single entity, these complications in fact comprise a heterogeneous group. Specific subgroups may be associated with distinct mortality risks.Medical records of all patients who underwent device extraction for CIED-related infection at a single tertiary referral center between 1991 and 2007 were reviewed. Infections were divided into four subgroups: primary pocket site infection (PPSI), pocket site infection with bacteremia, primary/isolated bacteremia (PIB), and device-related infective endocarditis (DRIE). Clinical presentation, laboratory data, and mortality rates were obtained by chart review and by querying the Social Security Death Index.A total of 387 cases were analyzed. The overall in-hospital and 1-year all-cause mortality rates were 7.2% and 25.3%, respectively. Patients with PIB or DRIE had significantly higher mortality rates (hazard ratio [HR] 2.3; 95% confidence interval [CI] 1.2-4.6 and HR 2.5; 95% CI 1.6-4.1, respectively) when compared with patients in the PPSI group. Patients who did not receive a new device during the initial admission also had a higher 1-year mortality rate compared to those who did (HR 2.7; 95% CI 1.8-4.1).Our patients with CIED-related infections requiring extraction/hospitalization had a significant mortality risk. Presence of pocket site infection carried a more favorable prognosis, regardless of the presence of bacteremia. Early detection and prevention of CIED-related infections with PIB (i.e., no pocket site involvement), especially for high-risk populations, is needed.

The fast intracellular multiplication of apicomplexan parasites including Toxoplasma and Plasmodium, requires large amounts of lipids necessary for the membrane biogenesis of new progenies. Hence, the study of lipids is fundamental in order to understand the biology and pathogenesis of these deadly organisms. Much has been reported on the importance of polar lipids, e.g. phospholipids in Plasmodium. Comparatively, little attention has been paid to the metabolism of neutral lipids, including sterols, steryl esters and acylglycerols. In eukaryotic cells, free sterols are membrane components whereas steryl esters and acylglycerols are stored in cytosolic lipid inclusions. The first part of this review describes the recent advances in neutral lipid synthesis and storage in Toxoplasma and Plasmodium. New potential pharmacological targets in the pathways producing neutral lipids are outlined. In addition to lipid bodies, Apicomplexa contain unique secretory organelles involved in parasite invasion named rhoptries. These compartments appear to sequester most of the cholesterol found in the exocytic pathway. The second part of the review focuses on rhoptry cholesterol and its potential roles in the biogenesis, structural organisation and function of these unique organelles among eukaryotes.

Recent studies have shown the feasibility of using Toxoplasma gondii as an expression system for heterologous protein. For better understanding of the mechanism of interferon-gamma (IFN-gamma) dependent immunity to T. gondii, the parasites were stably transfected with IFN-gamma gene, under control of the GRA1 promoter. Immunofluorescence analyses showed that recombinant mouse IFN-gamma localised to discrete punctuate structures consistent with dense granules and secreted into the vacuolar space. The production of IFN-gamma was detectable in both extracellular parasites and the parasite-infected cells. Growth of the recombinant parasites was inhibited in the mouse macrophage cell line (J774A.1 cells), but not in monkey kidney adherent fibroblasts (Vero cells), demonstrating the species-specificity of IFN-gamma. Addition of anti-mouse IFN-gamma antibody resulted in growth recovery of the recombinant parasites, suggesting that IFN-gamma, secreted from the parasitised host cells across the parasitophorous vacuole membrane, acted in a paracrine manner. Reverse transcription (RT)-PCR analysis revealed significant expression of inducible nitric oxide synthase mRNA and high levels of nitric oxide production in recombinant parasite-infected J774A.1 cells. A competitive inhibitor of the L-arginine-dependent effector pathway, N(G)-monomethyl-L-arginine, inhibited the reduction of recombinant parasite growth in J774A.1 cells. Taken together, our data suggest that the T. gondii expression system may provide a new tool for cytokine gene expression and that parasites engineered to express a cytokine gene may be rationally designed for use in studies on immune responses to T. gondii.

Background Bone biopsy is considered the gold standard for diagnosis and treatment of osteomyelitis (OM), but few studies have investigated the extent to which it influences antimicrobial therapy in non-vertebral bones. The purpose of this study was to evaluate clinician-initiated changes to empiric antimicrobial therapy after obtaining bone biopsy results. A secondary aim was to identify predictors of a positive bone culture. Methods We retrospectively reviewed all cases of non-vertebral OM in patients who underwent image-guided bone biopsies between 2009 and 2016. Data on pathologic and microbiologic yield were collected and logistic regression was used to determine potential factors affecting the microbiologic yield. Post-biopsy empiric antibiotics and final antibiotics were compared with determine if there was a change in antibiotic treatment after biopsy results were reported. Results We evaluated 203 bone biopsies in 185 patients. Samples from 115 (57%) cases were sent to pathology, of which 33 (29%) confirmed OM. All samples were sent to microbiology and 57 (28%) yielded a positive result. Diabetes (OR=2.39, P = 0.021) and white blood cell count (OR=1.13, P = 0.006) were significantly associated with positive bone cultures in multivariate analyses. There was no association between positive cultures and number of samples cultured, needle size, prior antibiotic use, or antibiotic-free days. Post-biopsy empiric antibiotics were given in 138 (68%) cases. Therapy was narrowed to target specific organisms in seven cases and changed due to inadequate empiric treatment in three cases. Targeted therapy was initiated in 4/65 cases, in which empiric antibiotics had been initially withheld. While final antibiotics were withheld in 38/146 with negative bone cultures, empiric antibiotics were discontinued in only eight cases. Conclusion In patients with non-vertebral OM, bone biopsy cultures rarely yielded results that necessitated changes in antibiotic management. Identified bone organisms were treated by empiric therapy in most patients. While bone biopsy remains the gold standard diagnostic test for OM, further work is needed to identify patients whose management may be impacted by this procedure. Disclosures All authors: No reported disclosures.

Bordetella pertussis was diagnosed in a human immunodeficiency virus-infected patient by a newly developed method in which bacterial DNA is amplified directly from sputum Gram-stained slides. The validation of the method is described along with an additional new PCR-based assay that can distinguish between B. pertussis and Bordetella holmesii .

Background Clinical practice guidelines are developed to assist in patient care. Physicians may assume that following such guidelines means practicing evidence-based medicine. However, the quality of supporting literature can vary greatly. Methods We analyzed the strength of recommendation and overall quality of evidence behind 41 Infectious Diseases Society of America (IDSA) guidelines released between January 1994 and May 2010. Individual recommendations were classified based on their strength of recommendation (levels A through C) and quality of evidence (levels I through III). Guidelines not following this format were excluded from further analysis. Evolution of IDSA guidelines was assessed by comparing 5 recently updated guidelines with their earlier versions. Results In the 41 analyzed guidelines, 4218 individual recommendations were found and tabulated. Fourteen percent of the recommendations were classified as level I, 31% as level II, and 55% as level III evidence. Among class A recommendations (good evidence for support), 23% were level I (≥1 randomized controlled trial) and 37% were based on expert opinion only (level III). Updated guidelines expanded the absolute number of individual recommendations substantially. However, few were due to a sizable increase in level I evidence; most additional recommendations had level II and III evidence. Conclusions More than half of the current recommendations of the IDSA are based on level III evidence only. Until more data from well-designed controlled clinical trials become available, physicians should remain cautious when using current guidelines as the sole source guiding patient care decisions.

Background Due to their unique ability to bind their targets with high fidelity, antibodies are used widely not only in biomedical research, but also in many clinical applications. Recombinant antibodies, including single chain variable fragments (scFv), are gaining momentum because they allow powerful in vitro selection and manipulation without loss of function. Regardless of the ultimate application or type of antibody used, precise understanding of the interaction between the antibody's binding site and its specific target epitope(s) is of great importance. However, such data is frequently difficult to obtain. Results We describe an approach that allows detailed characterization of a given antibody's target(s) using the yeast two-hybrid system. Several recombinant scFv were used as bait and screened against highly complex cDNA libraries. Systematic sequencing of all retained clones and statistical analysis allowed efficient ranking of the prey fragments. Multiple alignment of the obtained cDNA fragments provided a selected interacting domain (SID), efficiently narrowing the epitope-containing region. Interactions between antibodies and their respective targets were characterized for several scFv. For AA2 and ROF7, two conformation-specific sensors that exclusively bind the activated forms of the small GTPases Rab6 and Rab1 respectively, only fragments expressing the entire target protein's core region were retained. This strongly suggested interaction with a non-linear epitope. For two other scFv, TA10 and SF9, which recognize the large proteins giantin and non-muscle myosin IIA, respectively, precise antibody-binding regions within the target were defined. Finally, for some antibodies, secondary targets within and across species could be revealed. Conclusions Our method, utilizing the yeast two-hybrid technology and scFv as bait, is a simple yet powerful approach for the detailed characterization of antibody targets. It allows precise domain mapping for linear epitopes, confirmation of non-linear epitopes for conformational sensors, and detection of secondary binding partners. This approach may thus prove to be an elegant and rapid method for the target characterization of newly obtained scFv antibodies. It may be considered prior to any research application and particularly before any use of such recombinant antibodies in clinical medicine.

In the current post-genomic era, large scale efforts are underway to functionally explore the proteome by assembling large antibody libraries. However, because many proteins are modified post-translationally to regulate their function, collections of modification-specific sensors are also needed. Here we applied a novel approach to select monoclonal phosphospecific antibodies directly from the full-length protein and without up-front phosphoamino acid identification. We chose as antigen GRASP65, a well studied Golgi phosphoprotein. Bacterially produced full-length protein was first incubated with mitotic cytosol, thus allowing modification by naturally occurring kinases, and then used directly for affinity-based antibody selection using a single chain variable fragment phagemid library. In less than 1 week, three distinct and highly functional monoclonal phosphospecific antibodies against two GRASP65 epitopes were obtained and subsequently characterized. The presented approach is carried out fully in vitro, requires no prior knowledge of the phosphoamino acid identity, and is fast and inexpensive. It therefore has great potential to be an attractive alternative to classic animal-based protocols for the selection of post-translation modification sensors and thus to become an invaluable tool in our quest to understand the proteome in all its complexity.

Background Genomic, transcriptomic and proteomic projects often suffer from a lack of functional validation creating a strong demand for specific and versatile antibodies. Antibody phage display represents an attractive approach to select rapidly in vitro the equivalent of monoclonal antibodies, like single chain Fv antibodies, in an inexpensive and animal free way. However, so far, recombinant antibodies have not managed to impose themselves as efficient alternatives to natural antibodies. Results We developed a series of vectors that allow one to easily fuse single chain Fv antibodies to Fc domains of immunoglobulins, improving their sensitivity and facilitating their use. This series enables the fusion of single chain Fv antibodies with human, mouse or rabbit Fc so that a given antibody is no longer restricted to a particular species. This opens up unlimited multiplexing possibilities and gives additional value to recombinant antibodies. We also show that this multi-Fc species production system can be applied to natural monoclonal antibodies cloned as single chain Fv antibodies and we converted the widely used 9E10 mouse anti-Myc-tag antibody into a human and a rabbit antibody. Conclusion Altogether, this new expression system, that brings constant quality, sensitivity and unique versatility, will be important to broaden the use of recombinant and natural monoclonal antibodies both for laboratory and diagnosis use.

Antibodies are essential for the identification and characterization of proteins. In the current postgenomic era the need for highly specific antibodies has further increased not only for research applications but also because they represent one of the most promising therapeutic options, especially in the field of cancer treatment. One appealing approach for rapid and inexpensive antibody generation is the use of phage display. This technique allows for a fast and animal-free selection of highly functional alternatives to classical antibodies. However, one strong limitation of this recombinant approach has been the difficulty in producing and purifying antigens. These steps have to be adjusted for each new target, are time consuming and sometimes present an insurmountable obstacle. Here we report the development of new antibody selection approach where antigens are produced through in vitro translation and are used directly and without the need for purification. With this approach we were able to rapidly select recombinant antibodies directed against GFP and the mammalian protein tsg101, respectively. We believe that our method greatly facilitates antigen preparation and thus may broaden the use of the recombinant approach for antibody generation, especially since the technique could in the future be adapted to a high-throughput technology, thus further accelerating antibody selection.

In eukaryotic cells the neutral lipids, steryl esters and triacylglycerol, are synthesized by membrane-bound O -acyltransferases and stored in cytosolic lipid bodies. We show here that the intraerythrocytic stages of Plasmodium falciparum produce triacylglycerol using oleate and diacylglycerol as substrates. Parasite membrane preparations reveal a synthesis rate of 4.5±0.8 pmol min −1 mg −1 of protein with maximal production occurring in the mid- and late-trophozoite stages in both, membrane preparations and live parasites. In contrast to other eukaryotic cells, no discernable amounts of steryl esters are produced, and the parasite is insensitive to cholesterol esterification inhibitors. Synthesized neutral lipids are stored as lipid bodies in the parasite cytosol in a stage specific manner. Their biogenesis is not modified upon incubation with excess fatty acids or lipoproteins or after lipoprotein depletion of the culture medium. We investigated on the enzymes involved in neutral lipid synthesis and found that only one gene with significant homology to known members of the membrane-bound O -acyltransferase family is present in the P. falciparum genome. It encodes a microsomal transmembrane protein with a predicted size of 78.1 kDa, which we named Pf DGAT because of its close identity with various known acyl-CoA:diacylglycerol acyltransferases. Pf DGAT is expressed in a stage specific manner as documented by Western blotting and immunoprecipitation assays using antibodies against Toxoplasma DGAT, suggesting that Pf DGAT is the most likely candidate for plasmodial triacylglycerol synthesis.

Nonmotile bacteria that have been plated on agar generally display colony growth along the path of streaking. Rarely, in sputum samples, organisms that are part of the normal respiratory flora may be found unrelated to areas of streaking as groups of colonies arranged in a characteristic undulating pattern. Accidental contamination by a medical technologist or an external vector in the microbiology laboratory, such as an insect, might conceivably cause such a phenomenon. When accidental caus