Longitudinal Analysis of the Temporal Evolution of Acinetobacter baumannii Strains in Ohio, USA, by Using Rapid Automated Typing Methods

Genotyping methods are essential to understand the transmission dynamics of Acinetobacter baumannii. We examined the representative genotypes of A. baumannii at different time periods in select locations in Ohio, using two rapid automated typing methods: PCR coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), a form of multi-locus sequence typing (MLST), and repetitive-sequence-based-PCR (rep-PCR). Our analysis included 122 isolates from 4 referral hospital systems, in 2 urban areas of Ohio. These isolates were associated with outbreaks at 3 different time periods (1996, 2000 and 2005–2007). Type assignments of PCR/ESI-MS and rep-PCR were compared to each other and to worldwide (WW) clone types. The discriminatory power of each method was determined using the Simpson's index of diversity (DI). We observed that PCR/ESI-MS sequence type (ST) 14, corresponding to WW clone 3, predominated in 1996, whereas ST 12 and 14 co-existed in the intermediate period (2000) and ST 10 and 12, belonging to WW clone 2, predominated more recently in 2007. The shift from WW clone 3 to WW clone 2 was accompanied by an increase in carbapenem resistance. The DI was approximately 0.74 for PCR/ESI-MS, 0.88 for rep-PCR and 0.90 for the combination of both typing methods. We conclude that combining rapid automated typing methods such as PCR/ESI-MS and rep-PCR serves to optimally characterize the regional molecular epidemiology of A. baumannii. Our data also sheds light on the changing sequence types in an 11 year period in Northeast Ohio

American Gut: an Open Platform for Citizen Science Microbiome Research

McDonald D, Hyde E, Debelius JW, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18

Strain rate evaluation of phasic atrial function in hypertension

Background: Strain (SI) and strain rate (SR) measure regional myocardial deformation and may be a new technique to assess phasic atrial function. Objective: To examine the feasibility of using SI and SR to evaluate phasic atrial function in patients with mild hypertension (HT). Patients and methods: The study group comprised 54 patients with mild essential HT (29 women) and 80 age-matched normal controls (47 women). Standard two-dimensional and Doppler echocardiography was performed as well as Doppler tissue imaging. The following left atrial (LA) volumes were measured: (a) maximal LA volume or Vol ; (b) minimal LA volume or Vol; (c) just before the "p" wave on ECG (Vol). Phasic LA volumes were also calculated. Systolic (S-Sr), early diastolic (E-Sr), late diastolic (A-Sr) strain rate and SI were measured. Results: Despite no differences in indexed maximal LA volume with only mild increases in left ventricular mass in the HT cohort compared with normal subjects (mean (SD) 86 (18) g/m vs 67 (14) g/m; p = 0.001), E-Sr was significantly lower in the HT cohort. There was a corresponding reduction in indexed conduit volume in the HT cohort compared with normal subjects (10.5 (7.5) ml/m vs 13.8 (6.1) ml/m; p = 0.006). Global E-Sr showed modest negative correlations with LA Vol and LA ejection fraction. No significant difference was present in S-Sr, A-Sr or global atrial strain between the normal and HT cohorts. Conclusion: Mild HT results in a reduction in LA conduit volume, although maximal LA volume is unchanged. This is reflected by a reduction in E-Sr with preserved S-Sr andA-Sr