Clinical and Microbiological Characteristics of Patients with Complicated Intra-abdominal Infections in Intensive Care Unit

In order to investigate the clinical and microbiological characteristics of patients with complicated intra-abdominal infections(cIAIs)in intensive care unit(ICU),the clinical data of 612 cIAIs patients from January 2016 to December 2018 were retrospectively collected.Clinical characteristics,distribution of pathogens and drug resistance were statistically analyzed.It was found that patients with community-acquired intra-abdominal infections(CA-IAIs)made up a majority of cIAIs patients.The positive rate of abdominal drainage fluid culture was 55.56%.Gramnegative bacteria accounted for the majority,the most commonly isolated bacteria of which were Escherichia coli(20.96%),Klebsiella pneumoniae(10.20%)and Pseudomonas aeruginosa(5.57%).The most commonly isolated gram-positive bacteria were Enterococcus(16.88%)and Methicillinresistant staphylococcus aureus(MRSA,3.90%).Enterobacter isolates showed high resistance rate to most cephalosporins and low resistance rate to piperacillin/tazobactam and carbapenems.Extended spectrum beta-lactamase(ESBL)screen positive isolates from CA-IAIs patients showed an increasing trend in past three years.Enterococcus and MRSA showed high resistance rate to clindamycin,quinolone,erythromycin and tetracycline,while they showed high sensitivity rate to linezolid,tegacycline,teicoplanin and vancomycin.Our results indicate that isolated bacteria from abdominal drainage fluid show high resistance rates to commonly used antibiotics in ICU patients with cIAIs.The curative effects on diseases should be monitored continuously when antibiotics are used.Meanwhile,we should always keep eyes on drug-resistant bacteria,especially when the treatment efficacy is not good.

Optimizing calculation of phase screen distribution with minimum condition along an inhomogeneous turbulent path

When building an experimental platform for light propagation along an inhomogeneous turbulent path,it is very essential to set up the reasonable distribution of phase screen.Based on multi-layered model of phase screen,an iterative optimization algorithm of phase screen position is given in this paper.Thereafter,the optimal position of phase screens is calculated under the Hufnagel-Valley5/7 and Hefei-day turbulence profile.The results show that the positions of phase screen calculated by the iterative algorithm can fit well with the turbulence profile rather than mechanically placed phase screens at equal distance.Compared with the uniform distribution of phase screens position,the residual phase error of the iterative algorithm decreases very significantly.The similarity degree between them is minimal when number of layers is equal to two.