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The pandemic potential of avian influenza A(H7N9) virus: a review.

In March 2013 the first cases of human avian influenza A(H7N9) were reported to the World Health Organization. Since that time, over 650 cases have been reported. Infections are associated with considerable morbidity and mortality, particularly within certain demographic groups. This rapid increase in cases over a brief time period is alarming and has raised concerns about the pandemic potential of the H7N9 virus. Three major factors influence the pandemic potential of an influenza virus: (1) its ability to cause human disease, (2) the immunity of the population to the virus, and (3) the transmission potential of the virus. This paper reviews what is currently known about each of these factors with respect to avian influenza A(H7N9). Currently, sustained human-to-human transmission of H7N9 has not been reported; however, population immunity to the virus is considered very low, and the virus has significant ability to cause human disease. Several statistical and geographical modelling studies have estimated and predicted the spread of the H7N9 virus in humans and avian species, and some have identified potential risk factors associated with disease transmission. Additionally, assessment tools have been developed to evaluate the pandemic potential of H7N9 and other influenza viruses. These tools could also hypothetically be used to monitor changes in the pandemic potential of a particular virus over time.

Development and field evaluation of a method for detecting carbapenem-resistant bacteria in drinking water

In this study, a fluorogenic heterotrophic plate count test for drinking water was modified in order to detect the presence of carbapenem-resistant bacteria. Antimicrobial agents and concentrations were selected based on recoveries of known carbapenem-resistant and carbapenem-susceptible strains inoculated into simulated samples. The modified method was field-tested on 19 drinking water samples from the New Delhi, India distribution system. Samples exhibiting fluorescence indicated bacterial growth in the presence of the supplemented antimicrobial agents, and organisms from these samples were cultured. Twenty-one Gram-negative isolates were identified from nine of the 19 samples and the meropenem minimum inhibitory concentrations were determined. Ultimately, eight carbapenem-resistant organisms were isolated from five sampling sites within the New Delhi water distribution system.

Estimates of the risk of large or long-lasting outbreaks of Middle East respiratory syndrome after importations outside the Arabian Peninsula.

Abstract We quantify outbreak risk after importations of Middle East respiratory syndrome outside the Arabian Peninsula. Data from 31 importation events show strong statistical support for lower transmissibility after early transmission generations. Our model projects the risk of ≥10, 100, and 500 transmissions as 11%, 2%, and 0.02%, and ≥1, 2, 3, and 4 generations as 23%, 14%, 0.9%, and 0.05%, respectively. Our results suggest tempered risk of large, long-lasting outbreaks with appropriate control measures.

Effect of Meropenem Concentration on the Detection of Low Numbers of Carbapenem-Resistant Enterobacteriaceae

The nosocomial spread of carbapenem-resistant Enterobacteriaceae (CRE) is a serious concern for health care facilities ([1][1], [2][2]), and environmental sources are being increasingly implicated ([3][3][–][4][6][5]). Carbapenems can be used to select for CRE in environmental testing, but

Horizontal transfer of the blaNDM-1 gene to Pseudomonas aeruginosa and Acinetobacter baumannii in biofilms

Abstract Horizontal gene transfer has contributed to the global spread of the blaNDM‐1 gene. Multiple studies have demonstrated plasmid transfer of blaNDM‐1 between Gram‐negative bacteria, primarily Enterobacteriaceae species, but conjugational transfer of natural blaNDM‐1 plasmids from Enterobacteriaceae into Pseudomonas aeruginosa and Acinetobacter baumannii has not previously been shown. As P. aeruginosa and A. baumannii are both typically strong biofilm formers, transfer of natural blaNDM‐1 plasmids could potentially occur more readily in this environment. To determine whether natural blaNDM‐1 plasmids could transfer to P. aeruginosa or A. baumannii in biofilms, three clinical and environmental Enterobacteriaceae strains carrying NDM‐1‐encoding plasmids of different incompatibility types were mated with E. coli J53, producing E. coli J53‐ blaNDM‐1 transconjugants. Subsequently, dual‐species biofilms were created using the E. coli J53 transconjugants as plasmid donors and either P. aeruginosa or A. baumannii as recipients. Biofilm transfer of NDM‐encoding plasmids to P. aeruginosa and A. baumannii was successful from one and two E. coli J53‐ blaNDM‐1 transconjugants, respectively. This demonstrates the potential for the spread of blaNDM‐1, genes to P. aeruginosa and A. baumannii in clinical and environmental settings.

Vital signs: Estimated effects of a coordinated approach for action to reduce antibiotic-resistant infections in health care facilities - United States

Background: Treatments for health care–associated infections (HAIs) caused by antibiotic-resistant bacteria and Clostridium difficile are limited, and some patients have developed untreatable infections. Evidence-supported interventions are available, but coordinated approaches to interrupt the spread of HAIs could have a greater impact on reversing the increasing incidence of these infections than independent facility-based program efforts. Methods: Data from CDC’s National Healthcare Safety Network and Emerging Infections Program were analyzed to project the number of health care–associated infections from antibiotic-resistant bacteria orC. difficile bothwith and without a large scale national intervention that would include interrupting transmission and improved antibiotic stewardship. As an example, the impact of reducing transmission of one antibiotic-resistant infection (carbapenem-resistant Enterobacteriaceae [CRE]) on cumulative prevalence and number of HAI transmission events within interconnected groups of health care facilitieswasmodeled using two distinct approaches, a large scale and a smaller scale health care network. Results: Immediate nationwide infection control and antibiotic stewardship interventions, over 5 years, could avert an estimated 619,000 HAIs resulting from CRE, multidrug-resistant Pseudomonas aeruginosa, invasive methicillin-resistant Staphylococcus aureus (MRSA), or C. difficile. Compared with independent efforts, a coordinated response to prevent CRE spread across a group of inter-connected health care facilities resulted in a cumulative 74% reduction in acquisitions over 5 years in a 10-facility networkmodel, and 55% reduction over 15 years in a 102-facility network model. Conclusions: With effective action now, more than half a million antibiotic-resistant health care–associated infections could be prevented over 5 years.Models representing both large and small groups of interconnected health care facilities illustrate that a coordinated approach to interrupting transmission is more effective than historical independent facility-based efforts. Implications for Public Health: Public health–led coordinated prevention approaches have the potential to more completely address the emergence and dissemination of these antibiotic-resistant organisms and C. difficile than independent facility–based efforts.