Automated healthcare-associated infection surveillance using an artificial intelligence algorithm.

Healthcare-associated infections (HAIs) are among the most common adverse events in hospitals. We used artificial intelligence (AI) algorithms for infection surveillance in a cohort study. The model correctly detected 67 out of 73 patients with HAIs. The final model used a multilayer perceptron neural network achieving an area under receiver operating curve (AUROC) of 90.27%; specificity of 78.86%; sensitivity of 88.57%. Respiratory infections had the best results (AUROC ≥93.47%). The AI algorithm could identify most HAIs. AI is a feasible method for HAI surveillance, has the potential to save time, promote accurate hospital-wide surveillance, and improve infection prevention performance.

Secular trends in nosocomial bloodstream infections: antibiotic-resistant bacteria increase the total burden of infection.

BACKGROUND: It is unknown whether rising incidence rates of nosocomial bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) replace antibiotic-susceptible bacteria (ASB), leaving the total BSI rate unaffected. METHODS: We investigated temporal trends in annual incidence densities (events per 100 000 patient-days) of nosocomial BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA), ARB other than MRSA, and ASB in 7 ARB-endemic and 7 ARB-nonendemic hospitals between 1998 and 2007. RESULTS: 33 130 nosocomial BSIs (14% caused by ARB) yielded 36 679 microorganisms. From 1998 to 2007, the MRSA incidence density increased from 0.2 to 0.7 (annual increase, 22%) in ARB-nonendemic hospitals, and from 3.1 to 11.7 (annual increase, 10%) in ARB-endemic hospitals (P = .2), increasing the incidence density difference between ARB-endemic and ARB-nonendemic hospitals from 2.9 to 11.0. The non-MRSA ARB incidence density increased from 2.8 to 4.1 (annual increase, 5%) in ARB-nonendemic hospitals, and from 1.5 to 17.4 (annual increase, 22%) in ARB-endemic hospitals (P < .001), changing the incidence density difference from -1.3 to 13.3. Trends in ASB incidence densities were similar in both groups (P = .7). With annual increases of 3.8% and 5.4% of all nosocomial BSIs in ARB-nonendemic and ARB-endemic hospitals, respectively (P < .001), the overall incidence density difference of 3.8 increased to 24.4. CONCLUSIONS: Increased nosocomial BSI rates due to ARB occur in addition to infections caused by ASB, increasing the total burden of disease. Hospitals with high ARB infection rates in 2005 had an excess burden of BSI of 20.6 per 100 000 patient-days in a 10-year period, mainly caused by infections with ARB.

On the unzipping of multiwalled carbon nanotubes.

Graphene nanoribbons (GNRs) are very interesting structures which can retain graphene's high carrier mobility while presenting a finite bandgap. These properties make GNRs very valuable materials for the building of nanodevices. Unzipping carbon nanotubes (CNTs) is considered one of the most promising approaches for GNR controlled and large-scale production, although some of the details of the CNT unzipping processes are not completely known. In this work we have investigated CNT unzipping processes through fully atomistic molecular dynamics simulations using reactive force fields (ReaxFF). Multiwalled CNTs of different dimensions and chiralities under induced mechanical stretching were considered. Our results show that fracture patterns and stress profiles are highly CNT chirality dependent. Our results also show that the 'crests' (partially unzipped CNT regions presenting high curvature), originating from defective CNT areas, can act as a guide for the unzipping processes, which can explain the almost perfectly linear cuts frequently observed in unzipped CNTs.

Ordered phases of encapsulated diamondoids into carbon nanotubes.

Diamondoids are hydrogen-terminated nanosized diamond fragments that are present in petroleum crude oil at low concentrations. These fragments are found as oligomers of the smallest diamondoid, adamantane (C(10)H(16)). Due to their small size, diamondoids can be encapsulated into carbon nanotubes to form linear arrangements. We have investigated the encapsulation of diamondoids into single walled carbon nanotubes with diameters between 1.0 and 2.2 nm using fully atomistic simulations. We performed classical molecular dynamics and energy minimizations calculations to determine the most stable configurations. We observed molecular ordered phases (e.g. double, triple, 4- and 5-stranded helices) for the encapsulation of adamantane, diamantane, and dihydroxy diamantane. Our results also indicate that the functionalization of diamantane with hydroxyl groups can lead to an improvement on the molecular packing factor when compared to non-functionalized compounds. Comparisons to hard-sphere models revealed differences, especially when more asymmetrical diamondoids were considered. For larger diamondoids (i.e., adamantane tetramers), we have not observed long-range ordering but only a tendency to form incomplete helical structures. Our calculations predict that thermally stable (at least up to room temperature) complex ordered phases of diamondoids can be formed through encapsulation into carbon nanotubes.

Topologically closed macromolecules made of single walled carbon nanotubes-'super'-fullerenes.

We propose and theoretically investigated a new class of topologically closed macromolecules built using single walled carbon nanotubes. These macromolecules are based on the fullerene architecture. Classical molecular dynamics simulations were used to predict their stability, thermal, vibrational, and mechanical properties. These macromolecules, named 'super'-fullerenes, present high porosity, low density (approximately 1 g/cm3), and high surface area (approximately equal 2500 m2/g). Our results predict gas phase specific heat of about 0.4 Jg(-1)K(-1) at room temperature and high flexibility under compressive strains. These properties make these hypothetical macromolecules good candidates for gas storage material and biomolecular sieves.

Impact of hospital-wide infection rate, invasive procedures use and antimicrobial consumption on bacterial resistance inside an intensive care unit.

We performed a 30-month ecological study to determine the impact of hospital-wide antibiotic consumption, invasive procedure use and hospital-acquired infections (HAIs) on antibiotic resistance in an intensive care unit (ICU). Microbiological isolates from ICU patients with established diagnosis of hospital infection were monitored throughout the study. Overall hospital consumption per 100 patient-days of piperacillin-tazobactam, fluoroquinolones and cephalosporins increased from 1.9 to 2.3 defined daily doses (DDD) (P<0.01), from 4.7 to 10.3 DDD (P<0.01) and from 12.1 to 16.4 DDD (P<0.01), respectively. Bacterial multiresistance in ICU was identified in 31.3% (N=466) of isolates, with increasing resistance demonstrated for meropenem-resistant Klebsiella spp. (P=0.01) and meropenem-resistant Acinetobacter spp. (P=0.02). There was a positive correlation between multiresistance rate and DDD of cephalosporins (P<0.01) and fluoroquinolones (P=0.03). The rate of ceftazidime-resistant Klebsiella spp. correlated with DDD of fluoroquinolones and cephalosporins; the rate of ceftazidime-resistant Pseudomonas spp. correlated with consumption of cephalosporins, and rate of meticillin-resistant Staphylococcus aureus (MRSA) correlated with fluoroquinolone use. During the studied period, 36.9% (P<0.001) and 34.5% (P<0.01) of the changing multiresistance rate in ICU was associated with use of invasive procedures and overall HAI rate, respectively. Multiresistance rates in ICU are influenced by the variation in overall HAI rate, hospital-wide invasive procedures and antibiotic consumption outside the ICU.

Laboratory features for presumptive diagnosis of disseminated tuberculosis in HIV-infected patients.

Rapid diagnosis is crucial for adequate treatment of disseminated mycobacteriosis. We conducted a retrospective cohort study to identify clinical and laboratorial features of disseminated mycobacteriosis in human immunodeficiency virus (HIV) infected patients that could help to differentiate tuberculosis (TB) from non-tuberculous mycobacteria (NTM) disease. All patients diagnosed from 1996 to 2006 were reviewed. TB was diagnosed in 65 patients and NTM in 31. Patients with TB had higher median levels of aspartate aminotransferase (AST) (69.0 vs. 45.0, P = 0.02) and lactate dehydrogenase (LDH) (725.0 vs. 569.0, P = 0.03). AST and LDH may be valuable tools in differentiating disseminated TB from NTM in HIV-infected patients.

Critical steps in fluoroquinolones and carbapenems prescriptions: results from a prospective clinical audit.

Antibiotic misuse is associated with emergence of resistance and high expenditures. Fluoroquinolones (FQ) and carbapenems (CP) are drugs with considerable potential of resistance development and its disseminated use is a concern. We undertook a prospective clinical audit to evaluate prescriptions of FQ and CP in a multistep process. Each prescription was unfolded in the following steps: indication for antimicrobial therapy; adequacy of initial prescription, dosage and route; previous cultures; and parenteral-oral transition. There was no antibiotics indication in 8.9% of FQ and 1.5% of CP group (p = 0.07). In CP 25.8% of initial schemes were inappropriate (21% in FQ). Lack of switch to oral therapy comprised 25% of monthly costs of FQ. Inadequacy in initial choice accounted for 13.6% of CP expenses. We concluded that, in spite of infection control restrictive policies, inappropriateness of antibiotic usage is worrisome. Clinical audit in a multistep approach may identify possible flaws in this process.

A simple method for fixing, dehydrating and embedding pollen tubes cultivated in vitro for optical and transmission electron microscopy.

A simple method to cultivate pollen tubes in a gelatin medium is presented. After the growth of the pollen tubes in the culture medium, they are fixed, dehydrated, and embedded in resin for ultramicrotomy. The method is easy and does not require the purchase of special materials beyond those needed for the usual techniques for studying biological specimens under transmission electron microscopy.