Hypothalamic Regulation of Brown Adipose Tissue Thermogenesis and Energy Homeostasis

Obesity and diabetes are increasing at an alarming rate worldwide, but the strategies for the prevention and treatment of these disorders remain inadequate. Brown adipose tissue (BAT) is important for cold protection by producing heat using lipids and glucose as metabolic fuels. This thermogenic action causes increased energy expenditure and significant lipid/glucose disposal. In addition, BAT in white adipose tissue (WAT) or beige cells have been found and they also exhibit the thermogenic action similar to BAT. These data provide evidence indicating BAT/beige cells as a potential target for combating obesity and diabetes. Recent discoveries of active BAT and beige cells in adult humans have further highlighted this potential. Growing studies have also shown the importance of central nervous system in the control of BAT thermogenesis and WAT browning using animal models. This review is focused on central neural thermoregulation, particularly addressing our current understanding of the importance of hypothalamic neural signaling in the regulation of BAT/beige thermogenesis and energy homeostasis.

Nanostructure enhanced ionic transport in fullerene reinforced solid polymer electrolytes

We report a 6-fold ion conductivity enhancement in PEO/LiTFSI-based solid electrolytes upon the addition of fullerene derivatives.

[The ratio of Treg/Thl7 cells from mice infected with Plasmodium yoelii in the early stage of infection]

OBJECTIVE

To investigate the change of Treg/Th17 cell ratio in mice infected with Plasmodium yoelii 17XL in the early stage of infection.

METHODS

Forty 6-8 week-old female BALB/c mice were randomly divided into infection group and Treg blockade group. All the mice were infected by intraperitoneal injection with 1 x 10(6) P. yoelii 17XL-parasitized erythrocytes. Mice in Treg blockade group were intraperitoneally injected with 1 mg CD25 mAb before infection and on day 1 post-infection, respectively. Three healthy mice served as control. Tail vein blood samples were collected in two groups each with 10 mice during day 1-7 post-infection. The parasitemia was monitored daily by examining Giemsa-stained thin film. The survival rate of infected mice was calculated. Before infection, on day 3 and 5 post-infection, the spleen was aseptically removed from each mouse in infection group (n=3) and Treg blockade group (n=3), and splenocyte suspensions were prepared. The proportion of Treg and Th17 cells were analyzed by flow cytometry. The ratio of Treg/Th17 cells was calculated and the relative analysis of the percentage of Treg and Th17 cells was conducted.

RESULTS

Parasitemia appeared on day 2 post-infection in infection group. On day 5, the infection rate of P. yoelii in erythrocytes increased to (49.8±4.7)% with a survival rate of 60.0%. All mice died on day 6 post-infection. In Treg blockade group, P. yoelii 17XL-parasitized erythrocytes appeared on day 2 post-infection; the parasitemia was (10.0±3.5)% on day 5, and increased rapidly to 60.0% on day 7; all mice died on day 8. The percentages of Treg and Th17 cells reached (11.1±1.3)% and (16.7±3.3)% respectively on day 3 post-infection in infection group, and increased to (26.1±4.5)% and (19.6±2.6)% on day 5, considerably higher than that of the control (P<0.01). The ratio of Treg/Th17 cells was 0.7±0.1, 1.3±0.4 on day 3 and 5 post-infection in infection group, respectively, which was much lower than that of normal control (2.1±0.5) (P<0.01, P<0.05). On day 3 and 5 post-infection, the percentages of Treg cells in CD4+ T cells was (2.4±1.3)% and (4.3±2.9)%, respectively, and that of Th17 cells reached (26.1±2.2)% and (6.5±2.1)% in Treg blockade group. The ratio of Treg/Th17 cells in Treg blockade group was 0.1±0.1 and 0.7±0.4, respectively, which was considerably lower than that of the control (3.6±0.4)(P<0.01). The proportion of Treg cells in CD4+ T cells was positively correlated with that of Th17 cells (r=0.8166, P<0.01).

CONCLUSION

The ratio of Treg/Th17 cells significantly decreases in the early stage of P. yoelii 17XL infection.

Quality of teleoperator adaptive control for telerobotic operations

Extensive studies have been conducted on telerobotic operations for decades due to their widespread applications in a variety of areas. Most studies have been focused on two major issues: stability and telepresence. Few have studied the influence of the operation status of the teleoperator on the performance of telerobotic operations. As subnormal operation status of the teleoperator may result in insufficient and even incorrect operations, the quality of teleoperator (QoT) is an important impact on the performance of the telerobotic operations in terms of the efficiency and safety even if both the stability and telepresence are guaranteed. Therefore, this paper investigates the online identification of the QoT and its application to telerobotic operations. The QoT is identified based on five QoT indicators which are generated based on the teleoperator’s brain EEG signals. A QoT adaptive control method is designed to adapt the velocity and responsivity of the robotic system to the operation status of the teleoperator such that the teleoperation efficiency and safety can be enhanced. The online QoT identification method was conducted on various teleoperators and the QoT adaptive control method was implemented on a mobile manipulator teleoperation system. The experimental results demonstrated the effectiveness and advantages of the proposed methods.

Estrogen receptor beta treats Alzheimer's disease

In vitro studies have shown that estrogen receptor β can attenuate the cytotoxic effect of amyloid β protein on PC12 cells through the Akt pathway without estrogen stimulation. In this study, we aimed to observe the effect of estrogen receptor β in Alzheimer's disease rat models established by intraventricular injection of amyloid β protein. Estrogen receptor β lentiviral particles delivered via intraventricular injection increased Akt content in the hippocampus, decreased interleukin-1β mRNA, tumor necrosis factor α mRNA and amyloid β protein levels in the hippocampus, and improved the learning and memory capacities in Alzheimer's disease rats. Estrogen receptor β short hairpin RNA lentiviral particles delivered via intraventricular injection had none of the above impacts on Alzheimer's disease rats. These experimental findings indicate that estrogen receptor β, independent from estrogen, can reduce inflammatory reactions and amyloid β deposition in the hippocampus of Alzheimer's disease rats, and improve learning and memory capacities. This effect may be mediated through activation of the Akt pathway.

Stress prompts brown fat into combustion

Activation of dorsomedial hypothalamic-rostral medullary raphe neural signaling promotes brown fat thermogenesis, leading to elevated body temperature. In this issue, Kataoka et al. (2014) establish an important role for this brain-brown fat thermogenic action in psychological stress-induced hyperthermia in rats, implying a potential mechanism behind human psychogenic fever.

Differential characteristics and in vitro angiogenesis of bone marrow- and peripheral blood-derived endothelial progenitor cells: evidence from avian species

OBJECTIVES

This study was conducted to compare phenotypes and in vitro angiogenic capacity of putative endothelial progenitor cells (EPCs) derived from bone marrow (BM) and peripheral blood (PB), from an avian species.

MATERIALS AND METHODS

Mononuclear cells were isolated from chicken BM and PB (BMMNCs and PBMNCs) and cultured in EGM-2 medium. Cells at days 7-14 were used for the experiments. Expression of progenitor and endothelial markers, number of Dil-ac-LDL/lectin dual-positive cells and adipogenic and osteogenic differentiation were determined. Migration and in vitro angiogenic ability between BMMNC- and PBMNC-derived cells were compared.

RESULTS

PBMNCs developed typical EPC appearance, with initial spindle shape followed by a cobblestone form, whereas BMMNC-derived cells retained their constitutive spindle-like morphology throughout the study. Cells derived from both sources expressed CD133, CD31 and VEGFR-2, although PBMNCs-derived cells had lower CD133 expression. Nevertheless, number of Dil-ac-LDL/lectin dual-positive cells did not differ between groups. Adipogenic and osteogenic lineages were verified in BMMNC- but not in PBMNC-derived cells. PBMNC-derived cells formed tubular networks on Matrigel. However, BMMNC-derived cells formed few tube-like structures, which were not morphologically comparable to those developed by their counterparts.

CONCLUSION

Our results suggest that so called EPCs derived from BMMNCs are not 'true' EPCs, supporting previous findings on mammals that BM may not serve as an optimal isolation source of EPCs.

Vitamin D status and the risk of multiple sclerosis: a systematic review and meta-analysis

To estimate the associations between vitamin D status and multiple sclerosis (MS). We searched electronic databases of the human literature in PubMed, EMBASE and the Cochrane Library up to February, 2014 using the following keywords: 'vitamin D' or '25(OH)D' and 'status' or 'deficiency' or 'insufficiency' and 'multiple sclerosis'. A systematic review and meta-analysis were conducted on observational studies that reported the association between blood vitamin D levels and MS. Eleven studies met the inclusion criteria. 1007 patients and 829 controls were included. Results of our meta-analysis show that MS patients had lower mean levels of 25-hydroxyvitamin D [25(OH)D] than healthy controls (weighted mean difference[MD], -14.52, 95% confidence interval [CI], -23.83 to -5.22). There were statistically significant heterogeneity (P<0.00001; I(2)=92%). The significant heterogeneity may be due to the differences in ethnicity, country, season of blood sampling and age of the participants studied. To sum up, low vitamin D levels are associated with an increased risk of MS.

Caspofungin exposure-response relationships in adult patients with mucosal or invasive candidiasis

Caspofungin is an echinocandin antifungal agent administered once daily as an intravenous infusion. Relationships between caspofungin exposure and clinical efficacy and safety were investigated. End-of-infusion (CEOI ) and trough (C24 hours ) concentrations were obtained in 218 patients with mucosal (i.e., esophageal and/or oropharyngeal) candidiasis (MC) receiving caspofungin 35, 50, or 70 mg/day and 278 patients with invasive candidiasis (IC) receiving 50, 100, or 150 mg/day. Area under the plasma concentration-time curve (AUC0-24 hours ) was obtained in a subset of MC patients (n = 99). Odds ratios were estimated for the association between log-transformed PK and efficacy response and the occurrence of common adverse events. No pharmacokinetic or hybrid parameter (ratio of AUC:MIC, CEOI :MIC, C24 hours :MIC) was significantly correlated with overall treatment outcome in either MC or IC, although this patient population may exhibit confounding factors which masked a potential pharmacokinetic/pharmacodynamic relationship. An exploratory evaluation of MC identified significant pharmacokinetic correlations with endoscopic response, but not symptom response. Statistically significant associations were identified for IC patients with C. parapsilosis infections. Occurrence of clinical adverse events and/or laboratory abnormalities did not appear to be increased by higher caspofungin plasma concentrations. Caspofungin concentrations achieved with 50 mg/day are generally within the therapeutic window for the treatment of candidiasis.

Clinical application of Loewenstein Occupational Therapy Cognitive Assessment Battery-Second Edition in evaluating of cognitive function of Chinese patients with post-stroke aphasia

OBJECTIVE

To investigate the clinical application value of Loewenstein Occupational Therapy Cognitive Assessment battery in Chinese patients with post-stroke aphasia.

METHODS

Cognitive functions of 59 Chinese patients with aphasia following a stroke were assessed with the Chinese version of the second edition of LOTCA battery and their linguistic functions were tested with the Western Aphasia Battery (WAB) Scale, respectively. The Results of LOTCA were analyzed and compared across different groups, in the light of gender, age, educational background, the length of illness, and the degree of aphasia.

RESULTS

Neither the score of subtests of the LOTCA nor the overall scores of LOTCA of aphasia patients with different gender and educational background differed (all P>0.05). In different age groups, apart from thinking operation (F=3.373, P=0.016), visuomotor organization (F=3.124, P=0.022), attention (F=3.729, P=0.009) and the total score (F=2.683, P=0.041), there was no difference in terms of the other subtest scores of LOTCA (all P>0.05). In the groups of different length of time with illness, apart from orientation (F=2.982, P=0.039) and attention (F=3.485, P=0.022), the score of other subtests and the total score of LOTCA were not different (all P>0.05). In the groups of different degree of aphasia, apart from attention (F=2.061, P=0.074), both the score of other subtests and the total score of LOTCA differed (all P<0.05).

CONCLUSION

LOTCA might be suitable to assessing the cognitive ability of post-stroke Chinese patients with aphasia.

[Serum level of intercellular adhesion molecule-1 in patients with clonorchiasis and its impact on liver function]

OBJECTIVE

To investigate the serum level of intercellular adhesion molecule-1 (ICAM-1) in patients with clonorchiasis, and the relationship between ICAM-1 and liver function.

METHODS

Fifty untreated clonorchiasis patients and 20 normal controls were subjected in the present study. Plasma levels of total bilirubin (TBIL), albumin (ALB) and alanine aminotransferase (ALT) were determined by automatic biochemical analyzer. The patients were divided into three experiment groups (I, II, and III) by Child-Pugh classification. Serum level of sICAM-1 was determined by double-antibody sandwich ELISA. Radioimmunoassay was used to detect the content of interleukin-4(IL-4), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in serum. LAL tripeptide substrate staining quantitative method was used to detect the level of bacterial lipopolysaccharide (LPS) in plasma.

RESULTS

The level of sICAM-1, LPS, IL-4, IL-6, TNF-alpha, TBIL, and ALT [(729.34 +/- 75.67) microg/ml, (0.18 +/- 0.08) Eu/ml, (3.46 +/- 0.38) ng/ml, (223.48 +/- 46.90) pg/ml, (1.39 +/- 0.62) ng/ml, (15.45 +/- 10.81) micromol/L, and (39.25 +/- 8.82)IU/L, respectively] in serum or plasma of clonorchiasis patients were significantly higher than that of the control group [(269.15 +/- 38.21) microg/ml, (0.07 +/- 0.03) Eu/ml, (0.74 +/- 0.22) ng/ml, (106.06 +/- 32.96) pg/ml, (0.56 +/- 0.14) ng/ml, (6.31 +/- 4.70) micromol/L, (18.43 +/- 9.81) IU/L](P < 0.05 or P < 0.01). Plasma level of ALB [(28.35 +/- 5.38) g/L] was significantly lower than that of the control [(39.43 +/- 7.91) g/L] (P < 0.05). Correlation test showed that the sICAM-1 level in patients' sera was positively correlated with TBIL, ALT, and LPS (r = 0.662, 0.514, 0.499, P < 0.01), while negatively correlated with ALB (r = -0.423, P < 0.01). IL-4 level did not correlate with liver function parameters (P > 0.05). According to the Child-Pugh classification, the more serious the liver function damaged, the higher level of sICAM-1, LPS, IL-6 and TNF-alpha in the experiment groups. Significant differences were found between groups III and I (P < 0.01).

CONCLUSION

Higher serum levels of sICAM-1, LPS, IL-6, and TNF-alpha in patients with clonorchiasis take part in the process of liver injury induced by Clonorchis sinensis.

Browning of white adipose tissue: role of hypothalamic signaling

Two types of fat, white adipose tissue (WAT) and brown adipose tissue (BAT), exist in mammals including adult humans. While WAT stores excess calories and an excessive accumulation of fat causes obesity, BAT dissipates energy to produce heat through nonshivering thermogenesis for protection against cold environments and provides the potential for the development of novel anti-obesity treatments. The hypothalamus plays a central role in the control of energy balance. Specifically, recent observations indicate the importance of the dorsomedial hypothalamus (DMH) in thermoregulation. We have found that the orexigenic neuropeptide Y (NPY) in the DMH has distinct actions in modulating adiposity and BAT thermogenesis. Knockdown of NPY in the DMH elevates the thermogenic activity of classic BAT and promotes the development of brown adipocytes in WAT, leading to increased thermogenesis. These findings identify a novel potential target for combating obesity.

Comparison of the reaction time of wrist flexion and extension between patients with stroke and age-matched healthy subjects and correlation with clinical measures

BACKGROUND

Brain injury had an effect on reaction time (RT) and brain-injured patients were normally significantly slower than normal controls. The RT of the paretic upper limb (UL) in patients with stroke was slower than in a control group. The present study was designed to compare the RTs of the unaffected and affected sides in stroke survivors and those of normal subjects. This study also explores the relationships among wrist flexion and extension RTs in the affected side and the motor deficits of the UL as measured by clinical Composite Spasticity Index (CSI), Associated Reaction Rating Score (ARRS), and Wolf Motor Function Test (WMFT) scores.

METHODS

Ninety-eight hemiparetic stroke survivors and 20 normal subjects participated in the study. Abnormal muscle tone was measured by CSI. Associated reaction was measured by ARRS. Motor function was measured by WMFT. The subject was asked to flex or extend the affected and non-affected wrists as fast as possible, following an auditory "go" signal. An electrogoniometer attached to the wrist measured wrist flexion and extension angle. RT was defined as the time from the "go" signal to a change in wrist angle denoting movement onset. Clinical assessments and RT were conducted within one day. Differences in the variables between normal subjects and the unaffected sides of the stroke patients were analyzed using analysis of variance. Correlations were assessed by computing Spearman's correlation coefficient. The significance level was set at 5%.

RESULTS

RTs of wrist flexion and extension in the stroke survivors' affected hands were significantly longer than those in normal subjects and their unaffected hands (P < 0.01 for both). The wrist flexion RT moderately correlated with CSI (ρ = 0.412, P < 0.001) and ARRS (ρ = 0.341, P < 0.001) and with WMFT functional ability (negatively; ρ = -0.531, P < 0.001) and time score (ρ = 0.504, P < 0.001). Similarly, the wrist extension RT moderately correlated with CSI (ρ = 0.429, P < 0.001), ARRS (ρ = 0.374, P < 0.001), and with WMFT functional ability (negatively; ρ = -0.531, P < 0.001) and time score (ρ = 0.486, P < 0.001).

CONCLUSIONS

RTs of wrist flexion and extension on the stroke survivors' affected sides were significantly longer than those on the unaffected sides and those of normal subjects. The wrist flexion and extension RTs moderately correlated with CSI and ARRS and inversely with motor functional performance of the UL in patients with stroke.

Overexpression of neuropeptide Y in the dorsomedial hypothalamus causes hyperphagia and obesity in rats

We sought to determine a role for NPY overexpression in the dorsomedial hypothalamus (DMH) in obesity etiology using the rat model of adeno-associated virus (AAV)-mediated expression of NPY (AAVNPY) in the DMH. Rats received bilateral DMH injections of AAVNPY or control vector and were fed on regular chow. Five-week postviral injection, half the rats from each group were switched to access to a high-fat diet for another 11 weeks. We examined variables including body weight, food intake, energy efficiency, meal patterns, glucose tolerance, fat mass, plasma insulin, plasma leptin, and hypothalamic gene expression. Rats with DMH NPY overexpression had increased food intake and body weight and lowered metabolic efficiency. The hyperphagia was mediated through increased meal size during the dark. Although these rats had normal blood glucose, their plasma insulin levels were increased in both basal and glucose challenge conditions. While high-fat diet induced hyperphagia, obesity, and hyperinsulinemia, these effects were amplified in rats with DMH NPY overexpression. Arcuate Npy, agouti-related protein and proopiomelanocortin expression was appropriately regulated in response to positive energy balance. These results indicate that DMH NPY overexpression can cause hyperphagia and obesity and DMH NPY may have actions in glucose homeostasis.

[Pharmacognostical study of Cyperus rotundus growing in Wen-River area]

OBJECTIVE

To study the macroscopic, microscopic identification and chemical components of Cyperus rotundus growing in Wen-River area.

METHODS

The features of different parts of Cyperus rotundus were described by material morphology and microscopic identification, the chemical components of aerial part and rhizome of Cyperus rotundus were studied by chemical experiment and GC-MS analysis.

RESULTS

Summarized the transverse section structure of rhizome, stem and leaf of Cyperus rotundus, the chemical components of aerial part and the components and relative content of volatile oil in rhizome were determined.

CONCLUSION

This study provides reference for the drug identification and the daodi medicinal material exploitation of Cyperus rotundus.

Relationship between linguistic functions and cognitive functions in a clinical study of Chinese patients with post-stroke aphasia

BACKGROUND

There has been a long debate among scholars surrounding the relationship between language and cognition. The worldwide study of aphasia is actively exploring the function of language from cognitive point of view. This study aimed to investigate the relationship between linguistic functions and cognitive functions in a clinical study of Chinese patients with post-stroke aphasia.

METHODS

Cognitive functions of 63 Chinese patients with aphasia following a stroke were assessed with the Chinese version of the second edition of Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) battery and their linguistic functions were tested with the Western Aphasia Battery (WAB) Scale, respectively. The correlation between the results observed on the LOTCA battery and those on the WAB was analyzed. Aphasia quotient, performance quotient, cortical quotient, and linguistic function of the patients were compared. Then, each language function was analyzed by way of dependent adopt multiple regression analysis.

RESULTS

The total score of 63 patients as shown on the LOTCA battery was significantly correlated with the aphasia quotient, performance quotient, and cortical quotient observed on the WAB Scale (P < 0.05, P < 0.01). However, the correlation between visuomotor organization under LOTCA and repeat under WAB was not significant (P > 0.05). The attention of LOTCA and WAB's spontaneous speech, repeat, naming, and aphasia quotient was not relevant either (P > 0.05). In addition, correlations between the results observed on the LOTCA battery and the WAB were significant (P < 0.05, P < 0.01). Among the significant variables finally entered into the standardized canonical discriminant functions, main factors affected the aphasia. Multiple regression analysis showed that orientation, spatial perception, and visual perception had a notable influence on aphasia quotient and naming. Orientation and thinking operation was found to have a notable influence on spontaneous speech. Spatial perception and visual perception was found to have a notable influence on auditory comprehension. Thinking operation and orientation was found to have an obvious influence on reading. Thinking operation, spatial perception, and attention was found to have a notable effect on writing (P < 0.01).

CONCLUSION

There exists a close relationship between linguistic functions and cognitive orientation, spatial perception, visual perception, and thinking operation in a clinical study of Chinese patients with post-stroke aphasia.

In vitro evaluation of enhancing effect of borneol on transcorneal permeation of compounds with different hydrophilicities and molecular sizes

To investigate the enhancing effect of borneol on transcorneal permeation of compounds with different hydrophilicities and molecular sizes. Six compounds, namely rhodamine B, sodium-fluorescein, fluorescein isothiocyanate (FITC) dextrans of 4, 10, 20 and 40 kDa were selected as model drugs. Permeation studies were performed using excised cornea of rabbits by a Franz-type diffusion apparatus. The safety of borneol was assessed on the basis of corneal hydration level and Draize eye test. The application of 0.2% borneol to the cornea increased the apparent permeability coefficient by 1.82-(P<0.05), 2.49-(P<0.05), 4.18-(P<0.05) and 1.11-fold (not significant) for rhodamine B, sodium-fluorescein, FITC-dextrans of 4 and 10 kDa, respectively. No significant permeability enhancement of FITC dextrans of 10, 20 and 40 kDa with borneol was found compared to control. The permeability coefficient enhanced by 0.2% borneol was linear correlated to the molecular weight of model drugs (R(2)=0.9976). With the 0.05%, 0.1% and 0.2% borneol application, the corneal hydration values were <83% and Draize scores were <4. Borneol may improve the transcorneal penetration of both hydrophilic and lipophilic compounds without causing toxic reactions, especially hydrophilic ones. Furthermore, 0.2% borneol can enhance the permeation of hydrophilic compounds with molecular weight ≤4 kDa. Hence, borneol can be considered as a safe and effective penetration enhancer for ocular drug administration.

Overexpression of neuropeptide Y in the dorsomedial hypothalamus increases trial initiation but does not significantly alter concentration-dependent licking to sucrose in a brief-access taste test

Evidence in the literature raises the possibility that alterations in neuropeptide Y (NPY) in the dorsomedial hypothalamus (DMH) may contribute to hyperphagia leading to body weight gain. Previously, we have shown that compared to AAVGFP controls, adeno-associated virus (AAV)-mediated overexpression of NPY in the DMH of lean rats resulted in significantly higher body weight gain that was attributed to increased food intake, and this was further exacerbated by a high-fat diet. Here, we tested AAVNPY and AAVGFP control rats in a brief-access taste procedure (10-s trials, 30-min sessions) to an array of sucrose concentrations under ad libitum and partial food and water access conditions. The test allows for some segregation of the behavioral components by providing a measure of trial initiation (appetitive) and unconditioned licks at each concentration (consummatory). Consistent with previous findings suggesting that NPY has a primary effect on appetitive function, overexpression of DMH NPY did not significantly alter concentration-dependent licking response to sucrose but when tested in a non-restricted food and water schedule, AAVNPY rats initiated significantly more sucrose trials compared to AAVGFP controls in a brief-access taste test.

Epidemic of Klebsiella pneumoniae ST11 clone coproducing KPC-2 and 16S rRNA methylase RmtB in a Chinese University Hospital

BACKGROUND

Emergence of rmtB-positive Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-KP) poses a great threat to antimicrobial treatment options.

METHODS

From January 2010 to December 2010, non-duplicate KPC-KP isolates from our hospital were screened for rmtB and multiple other resistance determinants with PCR. Subsequent studies included MIC determination, PFGE, and multilocus sequence typing. Records from patients with KPC-KP isolated were retrospectively reviewed. Comparisons of molecular and clinical characteristics between rmtB-positive and rmtB-negative isolates were systematically performed, as well as the environmental colonization study in ICU wards.

RESULTS

A total of 84 KPC-KP strains were collected, including 48 rmtB-positive KPC-KP (RPKP) and 36 rmtB-negative KPC-KP (RNKP) isolates. All KPC-KP isolates were multidrug resistant, with colistin and tigecycline being the most active agents. Compared with RNKP, RPKP displayed a much severer resistance phenotype. Susceptibility rates for amikacin (0% for RPKP versus 88.9% for RNKP, p < 0.01), fosfomycin (8.5% for RPKP versus 88.9% for RNKP, p < 0.01), and minocycline (6.7% for RPKP versus 52.8% for RNKP, p < 0.01), were all significantly lower in RPKP strains. Isolates belonging to PFGE pulsetype A and sequence type 11 were predominant in both groups, including 39 (81.3%) RPKP and 22 (61.1%) RNKP isolates. Nevertheless, RNKP showed more complex genetic backgrounds compared with RPKP. Diverse clinical characteristics were found in both cohorts, however, no significant differences were observed between RPKP and RNKP patients.

CONCLUSIONS

RPKP strains have spread widely and gradually replaced RNKP in our hospital. They seemed to show much severer resistance phenotypes compared with RNKP and had a bigger dissemination potential. Prudent use of available active agents combined with good control practices is therefore mandatory.