Successes and Short Comings in Four Years of an International External Quality Assurance Program for Animal Influenza Surveillance.

The US National institutes of Health-Centers of Excellence for Influenza Research and Surveillance is a research consortium that funds numerous labs worldwide to conduct influenza A surveillance in diverse animal species. There is no harmonization of testing procedures among these labs; therefore an external quality assurance (EQA) program was implemented to evaluate testing accuracy among labs in the program in 2012. Accurate detection of novel influenza A variants is crucial because of the broad host range and potentially high virulence of the virus in diverse species. Two molecular detection sample sets and 2 serology sample sets (one with avian origin isolates, and one with mammalian origin isolates each) were made available at approximately six month intervals. Participating labs tested the material in accordance with their own protocols. During a five year period a total of 41 labs from 23 countries ordered a total of 132 avian molecular, 121 mammalian molecular and 90 serology sample sets. Testing was completed by 111 individuals. Detection of type A influenza by RT-PCR was reliable with a pass rate (80% or greater agreement with expected results) of 86.6% for avian and 86.2% for mammalian origin isolates. However, identification of subtype by RT-PCR was relatively poor with 54.1% and 75.9% accuracy for avian and mammalian influenza isolates respectively. Serological testing had an overall pass rate of 86.9% and 22/23 labs used commercial ELISA kits. Based on the results of this EQA program six labs modified their procedures to improve accuracy and one lab identified an unknown equipment problem. These data represent the successful implementation of an international EQA program for an infectious disease; insights into the logistics and test design are also discussed

Accuracy of subtype identification by RT-PCR (conventional and real-time).

<p>Accuracy of subtype identification by RT-PCR (conventional and real-time).</p

Evaluating the Effects of Chlortetracycline on the Proliferation of Antibiotic-Resistant Bacteria in a Simulated River Water Ecosystem▿

Antibiotics and antibiotic metabolites have been found in the environment, but the biological activities of these compounds are uncertain, especially given the low levels that are typically detected in the environment. The objective of this study was to estimate the selection potential of chlortetracycline (CTC) on the antibiotic resistance of aerobic bacterial populations in a simulated river water ecosystem. Six replicates of a 10-day experiment using river water in continuous flow chemostat systems were conducted. Each replicate used three chemostats, one serving as a control to which no antibiotic was added and the other two receiving low and high doses of CTC (8 μg/liter and 800 μg/liter, respectively). The addition of CTC to the chemostats did not impact the overall level of cultivable aerobic bacteria (P = 0.51). The high-CTC chemostat had significantly higher tetracycline-resistant bacterial colony counts than both the low-CTC and the control chemostats (P < 0.035). The differences in resistance between the low-CTC and control chemostats were highly nonsignificant (P = 0.779). In general a greater diversity of tet resistance genes was detected in the high-CTC chemostat and with a greater frequency than in the low-CTC and control chemostats. Low levels of CTC in this in vitro experiment did not select for increased levels of tetracycline resistance among cultivable aerobic bacteria. This finding should not be equated with the absence of environmental risk, however. Low concentrations of antibiotics in the environment may select for resistant bacterial populations once they are concentrated in sediments or other locations

Quantifying the effect of swab pool size on the detection of influenza A viruses in broiler chickens and its implications for surveillance

Abstract Background Timely diagnosis of influenza A virus infections is critical for outbreak control. Due to their rapidity and other logistical advantages, lateral flow immunoassays can support influenza A virus surveillance programs and here, their field performance was proactively assessed. The performance of real-time polymerase chain reaction and two lateral flow immunoassay kits (FluDETECT and VetScan) in detecting low pathogenicity influenza A virus in oropharyngeal swab samples from experimentally inoculated broiler chickens was evaluated and at a flock-level, different testing scenarios were analyzed. Results For real-time polymerase chain reaction positive individual-swabs, FluDETECT respectively detected 37% and 58% for the H5 and H7 LPAIV compared to 28% and 42% for VetScan. The mean virus titer in H7 samples was higher than for H5 samples. For real-time polymerase chain reaction positive pooled swabs (containing one positive), detections by FluDETECT were significantly higher in the combined 5- and 6-swab samples compared to 11-swab samples. FluDETECT detected 58%, 55.1% and 44.9% for the H7 subtype and 28.3%, 34.0% and 24.6% for the H5 in pools of 5, 6 and 11 respectively. In our testing scenario analysis, at low flock-level LPAIV infection prevalence, testing pools of 11 detected slightly more infections while at higher prevalence, testing pools of 5 or 6 performed better. For highly pathogenic avian influenza virus, testing pools of 11 (versus 5 or 6) detected up to 5% more infections under the assumption of similar sensitivity across pools and detected less by 3% when its sensitivity was assumed to be lower. Conclusions Much as pooling a bigger number of swab samples increases the chances of having a positive swab included in the sample to be tested, this study’s outcomes indicate that this practice may actually reduce the chances of detecting the virus since it may result into lowering the virus titer of the pooled sample. Further analysis on whether having more than one positive swab in a pooled sample would result in increased sensitivity for low pathogenicity avian influenza virus is needed