EPI-Net One Health reporting guideline for antimicrobial consumption and resistance surveillance data: a Delphi approach.

Strategic and standardised approaches to analysis and reporting of surveillance data are essential to inform antimicrobial resistance (AMR) mitigation measures, including antibiotic policies. Targeted guidance on linking full-scale AMR and antimicrobial consumption (AMC)/antimicrobial residues (AR) surveillance data from the human, animal, and environmental sectors is currently needed. This paper describes the initiative whereby a multidisciplinary panel of experts (56 from 20 countries-52 high income, 4 upper middle or lower income), representing all three sectors, elaborated proposals for structuring and reporting full-scale AMR and AMC/AR surveillance data across the three sectors. An evidence-supported, modified Delphi approach was adopted to reach consensus among the experts for dissemination frequency, language, and overall structure of reporting; core elements and metrics for AMC/AR data; core elements and metrics for AMR data. The recommendations can support multisectoral national and regional plans on antimicrobials policy to reduce resistance rates applying a One Health approach.

Interaction Mode of the Novel Monobactam AIC499 Targeting Penicillin Binding Protein 3 of Gram-Negative Bacteria.

Novel antimicrobial strategies are urgently required because of the rising threat of multi drug resistant bacterial strains and the infections caused by them. Among the available target structures, the so-called penicillin binding proteins are of particular interest, owing to their good accessibility in the periplasmic space, and the lack of homologous proteins in humans, reducing the risk of side effects of potential drugs. In this report, we focus on the interaction of the innovative ß-lactam antibiotic AIC499 with penicillin binding protein 3 (PBP3) from Escherichia coli and Pseudomonas aeruginosa. This recently developed monobactam displays broad antimicrobial activity, against Gram-negative strains, and improved resistance to most classes of ß-lactamases. By analyzing crystal structures of the respective complexes, we were able to explore the binding mode of AIC499 to its target proteins. In addition, the apo structures determined for PBP3, from P. aeruginosa and the catalytic transpeptidase domain of the E. coli orthologue, provide new insights into the dynamics of these proteins and the impact of drug binding.

Discovery of Pyrrolidine-2,3-diones as Novel Inhibitors of P. aeruginosa PBP3.

The alarming threat of the spread of multidrug resistant bacteria currently leaves clinicians with very limited options to combat infections, especially those from Gram-negative bacteria. Hence, innovative strategies to deliver the next generation of antibacterials are urgently needed. Penicillin binding proteins (PBPs) are proven targets inhibited by ß-lactam antibiotics. To discover novel, non-ß-lactam inhibitors against PBP3 of Pseudomonas aeruginosa, we optimised a fluorescence assay based on a well-known thioester artificial substrate and performed a target screening using a focused protease-targeted library of 2455 compounds, which led to the identification of pyrrolidine-2,3-dione as a potential scaffold to inhibit the PBP3 target. Further chemical optimisation using a one-pot three-component reaction protocol delivered compounds with excellent target inhibition, initial antibacterial activities against P. aeruginosa and no apparent cytotoxicity. Our investigation revealed the key structural features; for instance, 3-hydroxyl group (R2) and a heteroaryl group (R1) appended to the N-pyrroldine-2,3-dione via methylene linker required for target inhibition. Overall, the discovery of the pyrrolidine-2,3-dione class of inhibitors of PBP3 brings opportunities to target multidrug-resistant bacterial strains and calls for further optimisation to improve antibacterial activity against P. aeruginosa.

Risk factors for hospital readmission following complicated urinary tract infection.

Hospital readmissions following severe infections are a major economic burden on the health care system and have a negative influence on patients' quality of life. Understanding the risk factors for readmission, particularly the extent to which they could be prevented, is of a great importance. In this study we evaluated potentially preventable risk factors for 60-day readmission in patients surviving hospitalization for complicated urinary tract infection (cUTI). This was a multinational, multicentre retrospective cohort study conducted in Europe and the Middle East. Our cohort included survivors of hospitalization due to cUTI during the years 2013-2014. The primary outcome was 60-day readmission following index hospitalization. Patient characteristics that could have influenced readmission: demographics, infection presentation and management, microbiological and clinical data; were collected via computerized medical records from infection onset up to 60 days after hospital discharge. Overall, 742 patients were included. The cohort median age was 68 years (interquartile range, (IQR) 55-80) and 43.3% (321/742) of patients were males. The all-cause 60-day readmission rate was 20.1% (149/742) and more than half were readmitted for infection [57.1%, (80/140)]. Recurrent cUTI was the most frequent cause for readmission [46.4% (65/140)]. Statistically significant risk factors associated with 60-day readmission in multivariable analysis were: older age (odds ratio (OR) 1.02 for an one-year increment, confidence interval (CI) 1.005-1.03), diabetes mellitus (OR 1.63, 95% CI 1.04-2.55), cancer (OR 1.7, 95% CI 1.05-2.77), previous urinary tract infection (UTI) in the last year (OR 1.8, 95% CI: 1.14-2.83), insertion of an indwelling bladder catheter (OR 1.62, 95% CI 1.07-2.45) and insertion of percutaneous nephrostomy (OR 3.68, 95% CI 1.67-8.13). In conclusion, patients surviving hospitalization for cUTI are frequently re-hospitalized, mostly for recurrent urinary infections associated with a medical condition that necessitated urinary interventions. Interventions to avoid re-admissions should target these patients.

Risk factors for enterococcal urinary tract infections: a multinational, retrospective cohort study.

Complicated urinary tract infection (cUTI) is a frequent cause of morbidity. In this multinational retrospective cohort study, we aimed to demonstrate risk factors for enterococcal UTI. Univariate and multivariate analyses of risk factors for enterococcal infection were performed. Among 791 hospitalized patients with cUTI, enterococci accounted for approximately 10% of cases (78/791). Risk factors for enterococcal UTI in multivariable analysis were male gender, age range of 55-75 years, catheter-associated UTI, and urinary retention. This information may assist treating physicians in their decision-making on prescribing empiric anti-enterococcus treatment to hospitalized patients presenting with cUTI and thus improve clinical outcomes.

Correction: Freischem et al. Interaction Mode of the Novel Monobactam AIC499 Targeting Penicillin Binding Protein 3 of Gram-Negative Bacteria. Biomolecules 2021, 11, 1057.

In the original article [...].

Clinical outcomes of hospitalised patients with catheter-associated urinary tract infection in countries with a high rate of multidrug-resistance: the COMBACTE-MAGNET RESCUING study.

Background: Although catheter-associated urinary tract infection (CA-UTI) is a major healthcare-related problem worldwide, there is a scarcity of current data from countries with high antimicrobial resistance rates. We aimed to determine the clinical outcomes of patients with CA-UTI compared to those of patients with other sources of complicated urinary tract infection (cUTI), and to assess the impact of antimicrobial resistance. We also aimed to identify the factors influencing 30-day mortality among patients with CA-UTI. Methods: This was a multicentre, multinational retrospective cohort study including hospitalised adults with cUTI between January 2013 and December 2014 in twenty hospitals from eight countries from southern Europe, Turkey and Israel. The primary endpoint was 30-day mortality. The secondary endpoints were length of hospital stay, symptom improvement after 7 days' treatment, symptom recurrence at 30 days and readmission 60 days after hospital discharge. Results: Of the 807 cUTI episodes, 341 (42.2%) were CA-UTIs. The time from catheter insertion to cUTI diagnosis was less than 2 weeks in 44.6% of cases. Overall, 74.5% of cases had hospital or healthcare-acquired CA-UTI. Compared to patients with other cUTI aetiologies, those with CA-UTI had the following characteristics: they were more frequently males, older, admitted for a reason other than cUTI and admitted from a long-term care facility; had higher Charlson's comorbidity index; and more frequently had polymicrobial infections and multidrug-resistant Gram-negative bacteria (MDR-GNB). Patients with CA-UTI also had significantly higher 30-day mortality rates (15.2% vs 6%) and longer hospital stay (median 14 [interquartile range -IQR- 7-27] days vs 8 [IQR 5-14] days) than patients with cUTI of other sources. After adjusting for confounders, CA-UTI was not independently associated with an increased risk of mortality (odds ratio, 1.40; 95% confidence interval, 0.77-2.54), and neither was the presence of MDR-GNB. Conclusions: CA-UTI was the most frequent source of cUTI, affecting mainly frail patients. The mortality of patients with CA-UTI was high, though this was not directly related to the infection.

Risk Factors for Treatment Failure and Mortality Among Hospitalized Patients With Complicated Urinary Tract Infection: A Multicenter Retrospective Cohort Study (RESCUING Study Group).

Background: Complicated urinary tract infections (cUTIs) are responsible for a major share of all antibiotic consumption in hospitals. We aim to describe risk factors for treatment failure and mortality among patients with cUTIs. Methods: A multinational, multicentre retrospective cohort study, conducted in 20 countries in Europe and the Middle East. Data were collected from patients' files on hospitalised patients with a diagnosis of cUTI during 2013-2014. Primary outcome was treatment failure, secondary outcomes included 30 days all-cause mortality,among other outcomes. Multivariable analysis using a logistic model and the hospital as a random variable was performed to identify independent predictors for these outcomes. Results: A total of 981 patients with cUTI were included. Treatment failure was observed in 26.6% (261/981), all cause 30-day mortality rate was 8.7% (85/976), most of these in patients with catheter related UTI (CaUTI). Risk factors for treatment failure in multivariable analysis were ICU admission (OR 5.07, 95% CI 3.18-8.07), septic shock (OR 1.92, 95% CI 0.93-3.98), corticosteroid treatment (OR 1.92, 95% CI 1.12-3.54), bedridden (OR 2.11, 95%CI 1.4-3.18), older age (OR 1.02, 95% CI 1.0071.03-), metastatic cancer (OR 2.89, 95% CI 1.46-5.73) and CaUTI (OR 1.48, 95% CI 1.04-2.11). Management variables, such as inappropriate empirical antibiotic treatment or days to starting antibiotics were not associated with treatment failure or 30-day mortality. More patients with pyelonephritis were given appropriate empirical antibiotic therapy than other CaUTI [110/171; 64.3% vs. 116/270; 43%, p <0.005], nevertheless, this afforded no advantage in treatment failure rates nor mortality in these patients. Conclusions: In patients with cUTI we found no benefit of early appropriate empirical treatment on survival rates or other outcomes. Physicians might consider supportive treatment and watchful waiting in stable patients until the causative pathogen is defined.

Multiple polymerase gene mutations for human adaptation occurring in Asian H5N1 influenza virus clinical isolates.

The role of the influenza virus polymerase complex in host range restriction has been well-studied and several host range determinants, such as the polymerase PB2-E627K and PB2-D701N mutations, have been identified. However, there may be additional, currently unknown, human adaptation polymerase mutations. Here, we used a database search of influenza virus H5N1 clade 1.1, clade 2.3.2.1 and clade 2.3.4 strains isolated from 2008-2012 in Southern China, Vietnam and Cambodia to identify polymerase adaptation mutations that had been selected in infected patients. Several of these mutations acted either alone or together to increase viral polymerase activity in human airway cells to levels similar to the PB2-D701N and PB2-E627K single mutations and to increase progeny virus yields in infected mouse lungs to levels similar to the PB2-D701N single mutation. In particular, specific mutations acted synergistically with the PB2-D701N mutation and showed synergistic effects on viral replication both in human airway cells and mice compared with the corresponding single mutations. Thus, H5N1 viruses in infected patients were able to acquire multiple polymerase mutations that acted cooperatively for human adaptation. Our findings give new insight into the human adaptation of AI viruses and help in avian influenza virus risk assessment.

Predictive factors for multidrug-resistant gram-negative bacteria among hospitalised patients with complicated urinary tract infections.

Background: Patients with complicated urinary tract infections (cUTIs) frequently receive broad-spectrum antibiotics. We aimed to determine the prevalence and predictive factors of multidrug-resistant gram-negative bacteria in patients with cUTI. Methods: This is a multicenter, retrospective cohort study in south and eastern Europe, Turkey and Israel including consecutive patients with cUTIs hospitalised between January 2013 and December 2014. Multidrug-resistance was defined as non-susceptibility to at least one agent in three or more antimicrobial categories. A mixed-effects logistic regression model was used to determine predictive factors of multidrug-resistant gram-negative bacteria cUTI. Results: From 948 patients and 1074 microbiological isolates, Escherichia coli was the most frequent microorganism (559/1074), showing a 14.5% multidrug-resistance rate. Klebsiella pneumoniae was second (168/1074) and exhibited the highest multidrug-resistance rate (54.2%), followed by Pseudomonas aeruginosa (97/1074) with a 38.1% multidrug-resistance rate. Predictors of multidrug-resistant gram-negative bacteria were male gender (odds ratio [OR], 1.66; 95% confidence interval [CI], 1.20-2.29), acquisition of cUTI in a medical care facility (OR, 2.59; 95%CI, 1.80-3.71), presence of indwelling urinary catheter (OR, 1.44; 95%CI, 0.99-2.10), having had urinary tract infection within the previous year (OR, 1.89; 95%CI, 1.28-2.79) and antibiotic treatment within the previous 30 days (OR, 1.68; 95%CI, 1.13-2.50). Conclusions: The current high rate of multidrug-resistant gram-negative bacteria infections among hospitalised patients with cUTIs in the studied area is alarming. Our predictive model could be useful to avoid inappropriate antibiotic treatment and implement antibiotic stewardship policies that enhance the use of carbapenem-sparing regimens in patients at low risk of multidrug-resistance.

Cost of hospitalised patients due to complicated urinary tract infections: a retrospective observational study in countries with high prevalence of multidrug-resistant Gram-negative bacteria: the COMBACTE-MAGNET, RESCUING study.

OBJECTIVE: Complicated urinary tract infections (cUTIs) impose a high burden on healthcare systems and are a frequent cause of hospitalisation. The aims of this paper are to estimate the cost per episode of patients hospitalised due to cUTI and to explore the factors associated with cUTI-related healthcare costs in eight countries with high prevalence of multidrug resistance (MDR). DESIGN: This is a multinational observational, retrospective study. The mean cost per episode was computed by multiplying the volume of healthcare use for each patient by the unit cost of each item of care and summing across all components. Costs were measured from the hospital perspective. Patient-level regression analyses were used to identify the factors explaining variation in cUTI-related costs. SETTING: The study was conducted in 20 hospitals in eight countries with high prevalence of multidrug resistant Gram-negative bacteria (Bulgaria, Greece, Hungary, Israel, Italy, Romania, Spain and Turkey). PARTICIPANTS: Data were obtained from 644 episodes of patients hospitalised due to cUTI. RESULTS: The mean cost per case was €5700, with considerable variation between countries (largest value €7740 in Turkey; lowest value €4028 in Israel), mainly due to differences in length of hospital stay. Factors associated with higher costs per patient were: type of admission, infection source, infection severity, the Charlson comorbidity index and presence of MDR. CONCLUSIONS: The mean cost per hospitalised case of cUTI was substantial and varied significantly between countries. A better knowledge of the reasons for variations in length of stays could facilitate a better standardised quality of care for patients with cUTI and allow a more efficient allocation of healthcare resources. Urgent admissions, infections due to an indwelling urinary catheterisation, resulting in septic shock or severe sepsis, in patients with comorbidities and presenting MDR were related to a higher cost.

Surveillance of Severe Acute Respiratory Infection (SARI) for Hospitalized Patients in Northern Vietnam, 2011-2014.

Severe acute respiratory infections (SARI) are leading causes of hospitalization, morbidity, and mortality in children worldwide. The aim of this study was to identify viral pathogens responsible for SARI in northern Vietnam in the period from 2011 to 2014. Throat swabs and tracheal aspirates were collected from SARI patients according to WHO guidelines. The presence of 13 different viral pathogens (influenza A[H1N1]pdm09; A/H3N2; A/H5; A/H7 and B; para influenza 1,2,3; RSV; HMPV; adeno; severe acute respiratory syndrome-CoV and rhino) was tested by conventional/real-time reverse transcription-polymerase chain reaction. During the study period, 975 samples were collected and tested. More than 30% (32.1%, 313 samples) of the samples showed evidence of infection with influenza viruses, including A/H3N2 (48 samples), A (H1N1) pdm09 (221 samples), influenza B (42 samples), and co-infection of A (H1N1) pdm09 or A/H3N2 and influenza B (2 samples). Other respiratory pathogens were detected in 101 samples, including rhinovirus (73 samples), adenovirus (10 samples), hMPV (9 samples), parainfluenza 3 (5 samples), parainfluenza 2 (3 samples), and RSV (1 sample). Influenza A/H5, A/H7, or SARS-CoV were not detected. Respiratory viral infection, particularly infection of influenza and rhinoviruses, were associated with high rates of SARI hospitalization, and future studies correlating the clinical aspects are needed to design interventions, including targeted vaccination.

Viral co-infections among children with confirmed measles at hospitals in Hanoi, Vietnam, 2014.

OBJECTIVE: To characterize viral co-infections among representative hospitalized measles cases during the 2014 Hanoi outbreak. METHODS: Throat swabs were collected from 54 pediatric patients with confirmed measles, and molecular diagnostics performed for 10 additional viral respiratory pathogens (Influenza A/H1N1pdm09; A/H3N2 and influenza B; Parainfluenza 1, 2, 3; Respiratory Synctial Virus, RSV; human Metapneumovirus, hMPV; Adenovirus and Picornavirus). RESULTS: Twenty-one cases (38.9%) showed evidence of infection with other respiratory viruses: 15 samples contained measles plus one additional virus, and 6 samples contained measles plus 2 additional viruses. Adenovirus was detected as a predominant cause of co-infections (13 cases; 24.1%), followed by RSV (6 cases; 11.1%), A/H1N1pdm09 (3 cases; 5.6%), PIV3 (3 cases; 3.7%), Rhinovirus (3 cases; 3.7%) and hMPV (1 case; 1.96%). CONCLUSIONS: Viral co-infections identified from pediatric measles cases may have contributed to increased disease severity and high rate of fatal outcomes. Optimal treatment of measles cases may require control of multiple viral respiratory pathogens.

Towards Profiles of Resistance Development and Toxicity for the Small Cationic Hexapeptide RWRWRW-NH2.

RWRWRW-NH2 (MP196) is an amphipathic hexapeptide that targets the bacterial cytoplasmic membrane and inhibits cellular respiration and cell wall synthesis. In previous studies it showed promising activity against Gram-positive bacteria and no significant cytotoxicity or hemolysis. MP196 is therefore used as lead structure for developing more potent antibiotic derivatives. Here we present a more comprehensive study on the parent peptide MP196 with regard to clinically relevant parameters. We found that MP196 acts rapidly bactericidal killing 97% of initial CFU within 10 min at two times MIC. We were unable to detect resistance in standard 24 and 48 h resistance frequency assays. However, MP196 was effective against some but not all MRSA and VISA strains. Serum binding of MP196 was intermediate and we confirmed its low toxicity against mammalian cell lines. MP196 did neither induce NFκB activation nor cause an increase in IL8 levels at 250 µg/mL, and no IgE-dependent activation of basophil granulocytes was detected at 500 µg/mL. Yet, MP196 demonstrated acute toxicity in mice upon injection into the blood stream. Phase contrast microscopy of mouse blood treated with MP196 revealed a shrinking of erythrocytes at 250 µg/mL and severe morphological changes and lysis of erythrocytes at 500 µg/mL. These data suggest that MP196 derivatization directed at further lowering hemolysis could be instrumental in overcoming acute toxicity. The assessment of hemolysis is a critical step in the evaluation of the clinical potential of promising antimicrobial peptides and should be accompanied by microscopy-based morphological analysis of blood cells.

Investigational drugs to treat methicillin-resistant Staphylococcus aureus.

INTRODUCTION: Staphylococcus aureus remains one of the leading causes of morbidity and mortality worldwide. This is to a large extent due to antibiotic-resistant strains, in particular methicillin-resistant S. aureus (MRSA). While the toll of invasive MRSA infections appears to decrease in U.S. hospitals, the rate of community-associated MRSA infections remains constant and there is a surge of MRSA in many other countries, a situation that calls for continuing if not increased efforts to find novel strategies to combat MRSA infections. AREAS COVERED: This review provides an overview of current investigational drugs and therapeutic antibodies against S. aureus in early clinical development (up to phase II clinical development). It includes a short description of the mechanism of action and a presentation of microbiological and clinical data. EXPERT OPINION: Increased recent antibiotic development efforts and results from pathogenesis research have led to several new antibiotics and therapies, such as anti-virulence drugs, as well as a more informed selection of targets for vaccination efforts against MRSA. This developing portfolio of novel anti-staphylococcal drugs will hopefully provide us with additional and more efficient ways to combat MRSA infections in the near future and prevent us from running out of treatment options, even if new resistances arise.

Mode of action of closthioamide: the first member of the polythioamide class of bacterial DNA gyrase inhibitors.

OBJECTIVES: The spread of MDR bacteria represents a serious threat to human society and novel antibiotic drugs, preferably from new chemical classes, are urgently needed. Closthioamide was isolated from the strictly anaerobic bacterium Clostridium cellulolyticum and belongs to a new class of natural products, the polythioamides. Here, we investigated the antimicrobial activity and mechanism of action of closthioamide. METHODS: For assessing the antimicrobial activity of closthioamide, MIC values and killing kinetics were determined. To identify its target pathway, whole-cell-based assays were used including analysis of macromolecular synthesis and recording the susceptibility profile of a library of clones with down-regulated potential target genes. Subsequently, the inhibitory effect of closthioamide on the activity of isolated target enzymes, e.g. DNA gyrase and topoisomerase IV, was evaluated. RESULTS: Closthioamide had broad-spectrum activity against Gram-positive bacteria. Notably, closthioamide was very potent against MRSA and VRE strains. Closthioamide impaired DNA replication and inhibited DNA gyrase activity, in particular the ATPase function of gyrase and of topoisomerase IV, whereas there was little effect on the cleavage-rejoining function. Closthioamide also inhibited the relaxation activity of DNA gyrase, which does not require ATP hydrolysis, and thus may allosterically rather than directly interfere with the ATPase activity of gyrase. Cross-resistance to ciprofloxacin and novobiocin could not be detected in experimental mutants and clinical isolates. CONCLUSIONS: Closthioamide, a member of an unprecedented class of antibiotics, is a potent inhibitor of bacterial DNA gyrase; however, its molecular mechanism differs from that of the quinolones and aminocoumarins.

Virological characterization of influenza H1N1pdm09 in Vietnam, 2010-2013.

OBJECTIVES: Influenza A/H1N1pdm09 virus was first detected in Vietnam on May 31, 2009, and continues to circulate in Vietnam as a seasonal influenza virus. This study has monitored genotypic and phenotypic changes in this group of viruses during 2010-2013 period. DESIGN AND SETTING: We sequenced hemagglutinin (HA) and neuraminidase (NA) genes from representative influenza A/H1N1pdm09 and compared with vaccine strain A/California/07/09 and other contemporary isolates from neighboring countries. Hemagglutination inhibition (HI) and neuraminidase inhibition (NAI) assays also were performed on these isolates. SAMPLE: Representative influenza A/H1N1pdm09 isolates (n = 61) from ILI and SARI surveillances in northern Vietnam between 2010 and 2013. MAIN OUTCOME MEASURES AND RESULTS: The HA and NA phylogenies revealed six and seven groups, respectively. Five isolates (8·2%) had substitutions G155E and N156K in the HA, which were associated with reduced HI titers by antiserum raised against the vaccine virus A/California/07/2009. One isolate from 2011 and one isolate from 2013 had a predicted H275Y substitution in the neuraminidase molecule, which was associated with reduced susceptibility to oseltamivir in a NAI assay. We also identified a D222N change in the HA of a virus isolated from a fatal case in 2013. CONCLUSIONS: Significant genotypic and phenotypic changes in A/ H1N1pdm09 influenza viruses were detected by the National Influenza Surveillance System (NISS) in Vietnam between 2010 and 2013 highlighting the value of this system to Vietnam and to the region. Sustained NISS and continued virological monitoring of seasonal influenza viruses are required for vaccine policy development in Vietnam. 3.

Analysis of the mechanism of action of potent antibacterial hetero-tri-organometallic compounds: a structurally new class of antibiotics.

Two hetero-tri-organometallic compounds with potent activity against Gram-positive bacteria including multi-resistant Staphylococcus aureus (MRSA) were identified. The compounds consist of a peptide nucleic acid backbone with an alkyne side chain, substituted with a cymantrene, a (dipicolyl)Re(CO)3 moiety, and either a ferrocene (FcPNA) or a ruthenocene (RcPNA). Comparative proteomic analysis indicates the bacterial membrane as antibiotic target structure. FcPNA accumulation in the membrane was confirmed by manganese tracing with atomic absorption spectroscopy. Both organometallics disturbed several essential cellular processes taking place at the membrane such as respiration and cell wall biosynthesis, suggesting that the compounds affect membrane architecture. Correlating with enhanced antibacterial activity, oxidative stress was induced only by the ferrocene-substituted compound. The organometallics described here target the cytoplasmic membrane, a clinically proven antibacterial target structure, feature a bactericidal but non-bacteriolytic mode of action and limited cytotoxicity within the limits of solubility. Thus, FcPNA represents a promising lead structure for the development of a new synthetic class of antibiotics.

The genetic match between vaccine strains and circulating seasonal influenza A viruses in Vietnam, 2001-2009.

BACKGROUND: Vietnam is currently developing domestic capability to manufacture influenza vaccines but information on the genetic and antigenic characteristics of locally circulating seasonal influenza viruses is limited. To assess the relevance of WHO recommended vaccine strains to the situation in Vietnam, we analyzed the genetic relatedness of the hemagglutinin (HA) gene of seasonal influenza A viruses circulating in Vietnam from 2001 to 2009 to WHO recommended vaccine strains over the same period. METHODS AND PRINCIPAL FINDINGS: We sequenced the HA gene of 32 H1N1 and 44 H3N2 seasonal influenza A isolates from laboratory-based sentinel surveillance sites in Hanoi from 2001 to 2005 and from a national influenza surveillance system from 2005 to 2009. H1 and H3 HA phylogenetic trees rooted to vaccine strains A/Beijing/295/1995 (H1N1) and A/Moscow/10/1999 (H3N2), respectively, were constructed with contemporary HA sequences of isolates from neighboring countries. We found some genetic differences between seasonal influenza H3N2 viruses and three WHO influenza vaccine strains recommended for use in the Northern and Southern Hemispheres for the 2001-2004 and 2007-2008 seasons and close genetic identity of circulating H3N2 strains with the recommended WHO Southern Hemisphere vaccine strains for 2004 and 2009 seasons. The genetic similarity of circulating H1N1 strains with the WHO recommended vaccine strains are described for the study period 2001-2009. CONCLUSIONS: The HA gene of seasonal influenza virus strains in Vietnam (especially influenza A/H3N2) showed varying degrees of genetic identity compared with those of the Northern or Southern Hemisphere vaccine strains recommended by WHO. The close relatedness of the HA of Vietnamese strains and contemporary strains from nearby countries indicate a good genetic match of circulating strains during study period. Greater representation of virus isolates from South East Asia in the vaccine strain selection process is desirable of influenza vaccine development in Vietnam.

An Updated Loop-Mediated Isothermal Amplification Method for Rapid Diagnosis of H5N1 Avian Influenza Viruses.

We designed a new set of primers for reverse transcriptase loop-mediated isothermal amplification (RTLAMP) to specifically amplify the HA gene of avian influenza viruses subtype H5N1. By testing nine H5N1 virus strains and 41 clinical samples collected in Northern Vietnam, we found that the new primers showed higher sensitivity and specificity than the previously published RT-LAMP primers and were comparable to the RT-PCR method currently recommended by WHO. These results suggest that our RT-LAMP assay may be a better choice as a diagnostic tool for current H5N1 influenza virus infection.