Comparison of Novel and Established Nitrification Inhibitors Relevant to Agriculture on Soil Ammonia- and Nitrite-Oxidizing Isolates.

Nitrification inhibitors (NIs) applied to soil reduce nitrogen fertilizer losses from agro-ecosystems. NIs that are currently registered for use in agriculture appear to selectively inhibit ammonia-oxidizing bacteria (AOB), while their impact on other nitrifiers is limited or unknown. Ethoxyquin (EQ), a fruit preservative shown to inhibit ammonia-oxidizers (AO) in soil, is rapidly transformed to 2,6-dihydro-2,2,4-trimethyl-6-quinone imine (QI), and 2,4-dimethyl-6-ethoxy-quinoline (EQNL). We compared the inhibitory potential of EQ and its derivatives with that of dicyandiamide (DCD), nitrapyrin (NP), and 3,4-dimethylpyrazole-phosphate (DMPP), NIs that have been used in agricultural settings. The effect of each compound on the growth of AOB (Nitrosomonas europaea, Nitrosospira multiformis), ammonia-oxidizing archaea (AOA; "Candidatus Nitrosocosmicus franklandus," "Candidatus Nitrosotalea sinensis"), and a nitrite-oxidizing bacterium (NOB; Nitrobacter sp. NHB1), all being soil isolates, were determined in liquid culture over a range of concentrations by measuring nitrite production or consumption and qPCR of amoA and nxrB genes, respectively. The degradation of NIs in the liquid cultures was also determined. In all cultures, EQ was transformed to the short-lived QI (major derivative) and the persistent EQNL (minor derivative). They all showed significantly higher inhibition activity of AOA compared to AOB and NOB isolates. QI was the most potent AOA inhibitor (EC50 = 0.3-0.7 µM) compared to EQ (EC50 = 1-1.4 µM) and EQNL (EC50 = 26.6-129.5 µM). The formation and concentration of QI in EQ-amended cultures correlated with the inhibition patterns for all isolates suggesting that it was primarily responsible for inhibition after application of EQ. DCD and DMPP showed greater inhibition of AOB compared to AOA or NOB, with DMPP being more potent (EC50 = 221.9-248.7 µM vs EC50 = 0.6-2.1 µM). NP was the only NI to which both AOA and AOB were equally sensitive with EC50s of 0.8-2.1 and 1.0-6.7 µM, respectively. Overall, EQ, QI, and NP were the most potent NIs against AOA, NP, and DMPP were the most effective against AOB, while NP, EQ and its derivatives showed the highest activity against the NOB isolate. Our findings benchmark the activity range of known and novel NIs with practical implications for their use in agriculture and the development of NIs with broad or complementary activity against all AO.

An inception cohort study assessing the role of pneumococcal and other bacterial pathogens in children with influenza and ILI and a clinical decision model for stringent antibiotic use.

BACKGROUND: Influenza-like illness (ILI) is a common reason for paediatric consultations. Viral causes predominate, but antibiotics are used frequently. With regard to influenza, pneumococcal coinfections are considered major contributors to morbidity/mortality. METHODS: In the context of a perennial quality management (QM) programme at the Charité Departments of Paediatrics and Microbiology in collaboration with the Robert Koch Institute, children aged 0-18 years presenting with signs and symptoms of ILI were followed from the time of initial presentation until hospital discharge (Charité Influenza-Like Disease = ChILD Cohort). An independent QM team performed highly standardized clinical assessments using a disease severity score based on World Health Organization criteria for uncomplicated and complicated/progressive disease. Nasopharyngeal and pharyngeal samples were collected for viral reverse transcription polymerase chain reaction and bacterial culture/sensitivity and MaldiTOF analyses. The term 'detection' was used to denote any evidence of viral or bacterial pathogens in the (naso)pharyngeal cavity. With the ChILD Cohort data collected, a standard operating procedure (SOP) was created as a model system to reduce the inappropriate use of antibiotics in children with ILI. Monte Carlo simulations were performed to assess cost-effectiveness. RESULTS: Among 2,569 ChILD Cohort patients enrolled from 12/2010 to 04/2013 (55% male, mean age 3.2 years, range 0-18, 19% >5 years), 411 patients showed laboratory-confirmed influenza, with bacterial co-detection in 35%. Influenza and pneumococcus were detected simultaneously in 12/2,569 patients, with disease severity clearly below average. Pneumococcal vaccination rates were close to 90%. Nonetheless, every fifth patient was already on antibiotics upon presentation; new antibiotic prescriptions were issued in an additional 20%. Simulation of the model SOP in the same dataset revealed that the proposed decision model could have reduced the inappropriate use of antibiotics significantly (P<0.01) with an incremental cost-effectiveness ratio of -99.55€. CONCLUSIONS: Physicians should be made aware that in times of pneumococcal vaccination the prevalence and severity of influenza infections complicated by pneumococci may decline. Microbiological testing in combination with standardized disease severity assessments and review of vaccination records could be cost-effective, as well as promoting stringent use of antibiotics and a personalized approach to managing children with ILI.

Towards a personalised approach to managing influenza infections in infants and children - food for thought and a note on oseltamivir.

Acute respiratory infections represent common diseases in childhood and a challenge to infection control, public heath, and the clinical management of patients and their families. Children are avid spreaders of respiratory viruses, and seasonal outbreaks of influenza create additional disease burden and healthcare cost. Infants under the age of two and children with chronic conditions are at high risk. The absence of pre-defined risk factors however, does not protect from serious disease. Immunisation rates remain low, and physical interventions are of limited value in young children. Children with influenza may be contagious prior to the onset of symptoms, and school closures have been shown to have a temporary effect at most. The timely detection of influenza in at-risk patients is important to prevent hospital-based transmission and influenza-associated morbidity and mortality. Guidelines issued by professional associations and public health agencies need to be translated into everyday clinical practice. Antiviral therapy should be initiated early and monitored closely, including virologic and clinical outcomes. The duration of treatment and the decision to readmit children to schools and kindergartens should be adjusted to the individual child patient using evidence-based clinical and virologic criteria. This article presents lessons learnt from a quality management program for infants and children with influenza-like illness at the Charite Department of Paediatrics in collaboration with the National Reference Centre for Influenza at the Robert Koch Institute, in Berlin, Germany. The Charité Influenza-Like Disease (ChILD) Cohort was established during the 2009 influenza pandemic and encompasses nearly 4000 disease episodes to date.

Early detection of influenza A and B infection in infants and children using conventional and fluorescence-based rapid testing.

BACKGROUND: The appropriate management of infants and children with influenza depends on the accurate and timely diagnosis, ideally at the point of care (POC). OBJECTIVES: To evaluate the use of simultaneous RSV/influenza rapid testing with QuickVue™ test strips as well as (the use of) novel, fluorescence-based, rapid influenza antigen testing (SOFIA™) in infants and children with influenza-like illness (ILI). STUDY DESIGN: The Study was conducted in a real-time surveillance program at the Charité Department of Pediatrics in collaboration with the National Reference Centre for Influenza at the Robert Koch Institute (RKI) in Berlin, Germany (Charité Influenza-Like Disease=ChILD Cohort). RESULTS: During the 2010/2011 influenza season, 395 infants and children were simultaneously tested using QuickVue™ FluA&B and RSV10 rapid tests at POC compared to independent RT-PCR. Sensitivities were 62.7/67.8% for Influenza/RSV overall, but highest in infants <1 year with 76.0/76.2%. The evaluation of the fluorescence-based rapid test SOFIA™ with frozen laboratory samples (derived from the 2008/2009 and 2010/2011 national surveillance) yielded sensitivities of 97.7/86.7/86.7/81.7% for influenza A(H1N1)pdm09/A(H3N2)/B-Victoria/B-Yamagata in samples with CT values <34, and 80.2/79.8/67.5/62.5% for all CT values combined. The same method used at POC with 649 consecutive ChILD patients in 2011-2012 yielded sensitivity/specificity/PPV/NPV values of 78.9/99.7/96.6/97.3%. Again, sensitivities were highest in infants (85.7%) and small children <2 years (88%). CONCLUSIONS: Fluorescence-based rapid antigen testing provides a highly sensitive and specific tool for POC diagnostics of acute influenza in the paediatric age group, especially in infants and small children <2 years, when viral loads are at their peak and treatment decisions are imminent.