Diabetic foot ulcers—where do we stand microbiologically?

Foot ulcers in diabetics are prone to polymicrobial infection by bacteria as well as fungi. Infection retards healing of ulcers leading to gangrene and ultimately, amputation of the extremity. The choice of empiric antibiotic therapy is extrapolated from results of studies from other regions, western literature or infection at other sites which may be inappropriate. Thus, a study was conducted to determine microbial aetiology of diabetic foot ulcers and their susceptibility patterns. Pus aspirates or wound swabs were collected from foot ulcers of 70 diabetics at the time of admission and processed for isolation of bacteria (aerobic and anaerobic) and fungi according to standard protocols. Organisms were identified upto species level. Antimicrobial susceptibility testing was performed by Kirby Bauer disk diffusion method as per CLSI standards. One hundred forty-seven organisms were isolated from 70 specimens. Seventy-three percent showed polymicrobial growth. The proportion of Gram negative bacilli, Gram positive cocci, anaerobes and fungi were 57 %, 27 %, 4 % and 12 % respectively. Enterobacteriaceae were the predominant Gram negative bacilli and S.aureus, the predominant Gram positive cocci. Clostridium and Candida species were the commonest among anaerobes and fungi respectively. Twenty-three percent of S.aureus were MRSA and 23 % of Enterobacteriaceae were ESBL producers. Ps.aeruginosa strains demonstrated good susceptibility to antipseudomonal antimicrobials and 16.5 % strains were meropenem resistant. Due to the associated risk of increased morbidity and mortality in infected diabetic ulcers, the wide spectrum of organisms associated with it and their differing susceptibility profile, treatment should be individualised based on microbial culture and antimicrobial susceptibility results.     

Influenza hemagglutinin stem-fragment immunogen elicits broadly neutralizing antibodies and confers heterologous protection

Influenza hemagglutinin (HA) is the primary target of the humoral response during infection/vaccination. Current influenza vaccines typically fail to elicit/boost broadly neutralizing antibodies (bnAbs), thereby limiting their efficacy. Although several bnAbs bind to the conserved stem domain of HA, focusing the immune response to this conserved stem in the presence of the immunodominant, variable head domain of HA is challenging. We report the design of a thermotolerant, disulfide-free, and trimeric HA stem-fragment immunogen which mimics the native, prefusion conformation of HA and binds conformation specific bnAbs with high affinity. The immunogen elicited bnAbs that neutralized highly divergent group 1 (H1 and H5 subtypes) and 2 (H3 subtype) influenza virus strains in vitro. Stem immunogens designed from unmatched, highly drifted influenza strains conferred robust protection against a lethal heterologous A/Puerto Rico/8/34 virus challenge in vivo. Soluble, bacterial expression of such designed immunogens allows for rapid scale-up during pandemic outbreaks.Seasonal influenza outbreaks across the globe cause an estimated 250,000–500,000 deaths annually (1). Current influenza vaccines need to be updated every few years because of antigenic drift (2). Despite intensive monitoring, strain mismatch between vaccine formulation and influenza viruses circulating within the population has occurred in the past (2). Public health is further compromised when an unpredictable mixing event among influenza virus genomes leads to antigenic shift facilitating a potential pandemic outbreak. These concerns have expedited efforts toward developing a universal influenza vaccine.Neutralizing antibodies (nAbs) against hemagglutinin (HA) are the primary correlate for protection in humans and hence HA is an attractive target for vaccine development (3). The precursor polypeptide, HA0, is assembled into a trimer along the secretory pathway and transported to the cell surface. Cleavage of HA0 generates the disulfide-linked HA1 and HA2 subunits. Mature HA has a globular head domain which mediates receptor binding and is primarily composed of the HA1 subunit, whereas the stem domain predominantly comprises the HA2 subunit. The HA stem is trapped in a metastable state and undergoes an extensive low-pH-induced conformational rearrangement in the host-cell endosomes to adopt the virus–host membrane fusion-competent state (4, 5).The antigenic sites on the globular head of HA are subjected to heightened immune pressure resulting in escape variants, thereby limiting the breadth of head-directed nAbs (6). However, extensive efforts have resulted in the isolation of monoclonal antibodies (mAbs) that bind within the globular head and inhibit receptor attachment, which neutralize drifted variants of an HA subtype or heterosubtypic HA (7–16). The HA stem is targeted by several broadly neutralizing antibodies (bnAbs) with neutralizing activity against diverse influenza A virus subtypes (17). The epitopes of these bnAbs in the HA stem are more conserved across different influenza HA subtypes compared with the antigenic sites in the HA globular head (18).During a primary infection, the immunodominant globular head domain suppresses the response toward the conserved stem. Several efforts have been made to circumvent this problem. Repeated immunizations with full-length, chimeric HAs (cHAs) in a protracted vaccination regimen have been shown to boost stem-directed responses in mice (19). Alternatively, full-length HA presented on nanoparticles (np) has been shown to elicit stem-directed nAbs (20). Attempts have also been made to steer the immune response toward the conserved HA stem by hyperglycosylating the head domain (21). Although the aforementioned strategies need to be further evaluated and provide novel alternatives, detrimental interference from the highly variable immunodominant head domain in eliciting a broad functional response cannot be completely evaded. A “headless” stem domain immunogen offers an attractive solution. However, early attempts at expressing the HA2 subunit independently in a native, prefusion conformation were unsuccessful. In the absence of the head domain, the HA2 subunit expressed in Escherichia coli spontaneously adopted the low-pH conformation (22) in which the functional epitopes of stem-directed bnAbs are disrupted. More recently, the entire HA stem region has been expressed in a prefusion, native-like conformation in both prokaryotic and eukaryotic systems adopting multiple strategies (23–26).Design of independently folding HA stem fragments which adopt the prefusion HA conformation presents another approach to elicit bnAbs against influenza (27, 28). The A helix of the HA2 subunit contributes substantial contact surface to the epitope of stem-directed bnAbs such as CR6261, F10, and others. Although multivalent display of A helix on the flock house virus as a virus-like particle platform elicited cross-reactive antibodies, it conferred only minimal protection (20%) against virus challenge in mice (29).We report the design and characterization of engineered headless HA stem immunogens based on the influenza A/Puerto Rico/8/34 (H1N1) subtype. H1HA10-Foldon, a trimeric derivative of our parent construct (H1HA10), bound conformation-sensitive, stem-directed bnAbs such as CR6261 (30), F10 (31), and FI6v3 (32) with a high-affinity [equilibrium dissociation constant (K_D) of 10–50 nM]. The designed immunogens elicited broadly cross-reactive antiviral antibodies which neutralized highly drifted influenza virus strains belonging to both group 1 (H1 and H5 subtypes) and 2 (H3 subtype) in vitro. Significantly, stem immunogens designed from unmatched, highly drifted influenza strains conferred protection against a lethal (2LD₉₀) heterologous A/Puerto Rico/8/34 virus challenge in mice. Our immunogens confer robust subtype-specific and modest heterosubtypic protection in vivo. In contrast to previous stem domain immunogens (23–25), the designed immunogens were purified from the soluble fraction in E. coli. The HA stem-fragment immunogens do not aggregate even at high concentrations and are cysteine-free, which eliminates the complications arising from incorrect disulfide-linked, misfolded conformations. The aforementioned properties of the HA stem-fragment immunogens make it amenable for scalability at short notice which is vital during pandemic outbreaks.     

Is influenza-like illness a useful concept and an appropriate test of influenza vaccine effectiveness?

Purpose

To assess the utility of “influenza-like illness” (ILI) and whether it appropriately tests influenza vaccine effectiveness.

Principal results

The WHO and CDC definitions of “influenza-like illness” are similar. However many studies use other definitions, some not specifying a temperature and requiring specific respiratory and/or systemic symptoms, making many samples non-comparable. Most ILI studies find less than 25% of cases are RT-PCR-positive, those which test for other viruses and bacteria usually find multiple other pathogens, and most identify no pathogen in about 50% of cases. ILI symptom and symptom combinations do not have high sensitivity or specificity in identifying PCR-positive influenza cases. Rapid influenza diagnostic tests are increasingly used to screen ILI cases and they have low sensitivity and high specificity when compared to RT-PCR in identifying influenza.

Main conclusions

The working diagnosis of ILI presumes influenza may be involved until proven otherwise. Health care workers would benefit by renaming the WHO and CDC ILI symptoms and signs as “acute respiratory illness” and also using the WHO acute severe respiratory illness definition if the illness is severe and meets this criterion. This renaming would shift attention to identify the viral and bacterial pathogens in cases and epidemics, identify new pathogens, implement vaccination plans appropriate to the identified pathogens, and estimate workload during the viral season. Randomised controlled trials testing the effectiveness of influenza vaccine require all participants to be assessed by a gold standard (RT-PCR). ILI has no role in measuring influenza vaccine effectiveness. ILI is well established in the literature and in the operational definition of many surveillance databases and its imprecise definition may be inhibiting progress in research and treatment. The current ILI definition could with benefit be renamed “acute respiratory illness,” with additional definitions for “severe acute respiratory illness” (SARI) with RT-PCR testing for pathogens to facilitate prevention and treatment.     

The impact of telenursing on hope and perceived self-efficacy of the mothers of premature infants after discharge from the NICU

ObjectivesThis study aimed to investigate the impact of telenursing on the hope and perceived self-efficacy of the mothers of premature infants after discharge from the neonatal intensive care unit.MethodThe study method was a clinical trial. The research population consisted of all the mothers with premature infants whose neonates had recently been discharged from NICU. Seventy subjects were selected through convenience sampling and randomly assigned to intervention and control groups. The intervention group subjects received telenursing training for four weeks, while in the control group, no intervention was offered. The data collection tools included the Perceived Maternal Parenting Self-Efficacy Questionnaire (PMPS-Q) and the Hope Scale of Mothers of Premature Neonates Admitted to the Intensive Care Unit. Data analysis was performed using an independent t-test, two-way repeated-measures ANOVA, and one-way repeated measures ANOVA.ResultsThe results showed that telenursing improves hope (P < 0.05) and perceived self-efficacy (P < 0.05) in the mothers of premature infants after discharge from the NICU.ConclusionAccording to the obtained results, it is suggested that the necessary measures be taken to establish distance nursing in the neonatal intensive care unit. As a result, mothers of premature infants and the country's health system can benefit from the advantages as mentioned earlier.     

The N-terminal region containing the zinc finger domain of tobacco streak virus coat protein is essential for the formation of virus-like particles

Tobacco streak virus (TSV), a member of the genus Ilarvirus (family Bromoviridae), has a tripartite genome and forms quasi-isometric virions. All three viral capsids, encapsidating RNA 1, RNA 2 or RNA 3 and subgenomic RNA 4, are constituted of a single species of coat protein (CP). Formation of virus-like particles (VLPs) could be observed when the TSV CP gene was cloned and the recombinant CP (rCP) was expressed in E. coli. TSV VLPs were found to be stabilized by Zn²⁺ ions and could be disassembled in the presence of 500 mM CaCl_2. Mutational analysis corroborated previous studies that showed that an N-terminal arginine-rich motif was crucial for RNA binding; however, the results presented here demonstrate that the presence of RNA is not a prerequisite for assembly of TSV VLPs. Instead, the N-terminal region containing the zinc finger domain preceding the arginine-rich motif is essential for assembly of these VLPs.     

The prevalence of caries and tooth loss among participants in the Hispanic Community Health Study/Study of Latinos

Background.The Hispanic and Latino population is projected to increase from 16.7 percent to 30.0 percent by 2050. Previous U.S. national surveys had minimal representation of Hispanic and Latino participants other than Mexicans, despite evidence suggesting that Hispanic or Latino country of origin and degree of acculturation influence health outcomes in this population. In this article, the authors describe the prevalence and mean number of cavitated, decayed and filled surfaces, missing teeth and edentulism among Hispanics and Latinos of different national origins.Methods.Investigators in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)—a multicenter epidemiologic study funded by the National Heart, Lung, and Blood Institute with funds transferred from six other institutes, including the National Institute of Dental and Craniofacial Research—conducted in-person examinations and interviews with more than 16,000 participants aged 18 to 74 years in four U.S. cities between March 2008 and June 2011. The investigators identified missing, filled and decayed teeth according to a modified version of methods used in the National Health and Nutrition Examination Survey. The authors computed prevalence estimates (weighted percentages), weighted means and standard errors for measures.Results.The prevalence of decayed surfaces ranged from 20.2 percent to 35.5 percent, depending on Hispanic or Latino background, whereas the prevalence of decayed and filled surfaces ranged from 82.7 percent to 87.0 percent, indicating substantial amounts of dental treatment. The prevalence of missing teeth ranged from 49.8 percent to 63.8 percent and differed according to Hispanic or Latino background. Significant differences in the mean number of decayed surfaces, decayed or filled surfaces and missing teeth according to Hispanic and Latino background existed within each of the age groups and between women and men.Conclusions.Oral health status differs according to Hispanic or Latino background, even with adjustment for age, sex and other characteristics.Practical Implications.These data indicate that Hispanics and Latinos in the United States receive restorative dental treatment and that practitioners should consider the association between Hispanic or Latino origin and oral health status. This could mean that dental practices in areas dominated by patients from a single Hispanic or Latino background can anticipate a practice based on a specific pattern of treatment needs.     

Delayed right coronary ostial obstruction after J-valve deployment in transcatheter aortic valve implantation: A case report

BACKGROUND Aortic stenosis is the most common valve disease in adults.Transcatheter aortic valve implantation(TAVI)is being increasingly applied for intermediate-to lowrisk patients.Here,we describe an uncommon complication of delayed right coronary obstruction in a transapical TAVI case.CASE SUMMARY A 73-year-old woman with a EuroSCORE II of 1.21%underwent transapical TAVI because of severe aortic stenosis.The surgical procedure was uneventful.However,during routine monitoring after valve placement,the patient had a sudden onset of slow heart rate,the systolic blood pressure dropped sharply from 115 to 60 mmHg,and the central venous pressure abruptly increased from 10 to 33 cmH2O.The patient had a poor response to vasoactive agents.Transesophageal echocardiography revealed poor myocardial contractility,and electrocardiography showed a significant depression of ST-segment.Another angiography was performed immediately,which suggested complete obstruction of the right coronary artery.An emergency protocol was initiated.Cardiopulmonary bypass was established immediately.An aortic biological valve replacement under cardiopulmonary bypass was performed.CONCLUSION Perioperative monitoring,early recognition,and diagnosis of obstruction of coronary arteries in TAVI are important.Transesophageal echocardiography is a useful diagnostic and monitoring tool in this situation.Emergency protocols should be established during TAVI.     

Preclinical safety evaluation of IQG-607 in rats: Acute and repeated dose toxicity studies

In the present study, we evaluated the safety and the possible toxic effects of IQG-607 after acute and 90-day repeated administrations in rats. Single oral administration of IQG-607 (300 or 2000 mg/kg) on female rats did not result in any mortality. No gross lesions were observed in the animals at necropsy. Ninety-day administration test resulted in 20% of deaths, in both male and female rats administered with the highest dose of IQG-607, 300 mg/kg. Repeated administration of the IQG 607 (25, 100 and 300 mg/kg) did not result in any significant body mass alteration, or changes in food and water consumption. The most important clinical sign observed was salivation in both sexes. Importantly, long-term treatment with IQG-607 did not induce alterations in any hematological (for both sex) and serum biochemical (for female) parameters evaluated, even at the highest dose tested. Treatment of male rats with 100 or 300 mg/kg of IQG-607 decreased total cholesterol levels, while animals treated with 100 mg/kg also presented reduction on triglyceride levels. Of note, no treatment induced significant histopathological alterations in tissues of all organs and glands analyzed, even in that group that received the highest dose of IQG-607.