In vitro activity of linezolid alone and combined with other antibiotics against clinical enterococcal isolates

Wiener Medizinische Wochenschrift - The increasing incidence of antimicrobial resistance has led to research on finding new antimicrobial agents or identifying drug combinations with synergistic...     

Evaluation of biofilm production and characterization of genes encoding type III secretion system among Pseudomonas aeruginosa isolated from burn patients

Pseudomonas aeruginosa is one of the common pathogenic causes of serious infections in burn patients throughout the world. Type III secretion toxins are thought to promote the dissemination of P. aeruginosa from the site of infection, the bacterial evasion of the host immune response and inhibition of DNA synthesis leading to host cell death. A total of 96 isolates of P. aeruginosa were collected from wound infections of burn patients, from April to July 2010. Antimicrobial susceptibility of the isolates were determined by disk agar diffusion method. Polymerase chain reaction (PCR)-based method was used for targeting the genes encoding the type III secretion toxins.     

Amino acid substitution mutations and mRNA expression levels of the pbp5 gene in clinical Enterococcus faecium isolates conferring high level ampicillin resistance

In this study, clinical ampicillin‐resistant Enterococcus faecium isolates with minimum inhibitory concentrations (MICs) for ampicillin in the ranges from 128 to ?512 μg/mL (n = 17) and two ampicillin‐susceptible isolates (MIC 1 μg/mL) were investigated. No β‐lactamase production was detected in these isolates. Alterations in the C‐terminal part of pbp5 and levels of pbp5 mRNA expression were investigated by sequencing and quantitative real‐time qRT‐PCR, respectively. Sequencing analysis revealed five different pbp5 alleles (A to E) having differences in 18 amino acid positions spanning from residue 426 to 642. Allele A (V‐462 → A, H‐470 → Q, M‐485 → A, N‐496 → K, A‐499 → T, E‐525 → D, N‐546 → T, A‐558 → T, G‐582 → S, E‐629 → V, K‐632 → Q, and P‐642 → L) was the most frequent allele. The presence of just two susceptible isolates in allele E suggests a possible correlation between amino acid patterns and MIC, even if there is no discernible correlation with specific single amino acid differences. Also, these were the only isolates that showed much lower expression of class B penicillin‐binding protein 5 (PBP5) compared to isolates with MIC of 128 or greater. Thus, ampicillin MICs were correlated with PBP5 expression.     

Relationship between depression and apolipoproteins A and B: a case-control study

OBJECTIVE:

To investigate the relation between major depressive disorder and metabolic risk factors of coronary heart disease.

INTRODUCTION:

Little evidence is available indicating a relationship between major depressive disorder and metabolic risk factors of coronary heart disease such as lipoprotein and apolipoprotein.

METHODS:

This case–control study included 153 patients with major depressive disorder who fulfilled the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM‐IV), and 147 healthy individuals. All participants completed a demographic questionnaire and Hamilton rating scale for depression. Anthropometric characteristics were recorded. Blood samples were taken and total cholesterol, high‐ and low‐density lipoproteins and apolipoproteins A and B were measured. To analyze the data, t‐test, χ² test, Pearson correlation test and linear regression were applied.

RESULTS:

Depression was a negative predictor of apolipoprotein A (β = −0.328, p<0.01) and positive predictor of apolipoprotein B (β = 0.290, p<0.05). Apolipoprotein A was inversely predicted by total cholesterol (β = −0.269, p<0.05) and positively predicted by high‐density lipoprotein (β = 0.401, p<0.01). Also, low‐density lipoprotein was a predictor of apolipoprotein B (β = 0.340, p<0.01). The severity of depression was correlated with the increment in serum apolipoprotein B levels and the decrement in serum apolipoprotein A level.

CONCLUSION:

In view of the relationship between apolipoproteins A and B and depression, it would seem that screening of these metabolic risk factors besides psychological interventions is necessary in depressed patients.     

Assessment of the anterior chamber parameters after laser iridotomy in primary angle close suspect using Pentacam and gonioscopy

AIM:To investigate the role of fundus autofluorescence (FAF) both in the diagnosis and the preoperative and postoperative evaluation of patients with idiopathic macular hole (MH).METHODS: Forty eyes of 40 patients diagnosed as idiopathic MH between May 2010 and May 2011 were included in this retrospective study. All patients underwent full ophthalmologic examinations and imagings including fluorescein angiography, fundus autofluorescence (FAF) and optical coherence tomography. Thirty of these patients underwent MH surgery. FAF findings were associated with duration of symptoms, visual acuity at presentation, stage of MH, and postoperative anatomical correction.RESULTS:The mean duration of patients’ symptoms was 3.8±2.0 (1-9) months. The MH was stage 2 in 4 (10%), stage 3 in 24 (60%) and stage 4 in 12 (30%) eyes. The median preoperative best corrected visual acuity was 20/200 (between 20/800 and 20/100). Twenty-eight of cases (70%) showed a stellate appearance with dark radiating striae. Having a visual acuity ≥20/200 was significantly more common in eyes with stellate appearance (P<0.001). The mean duration of symptoms was significantly shorter in eyes with stellate appearance (2.75±0.8 vs 6.33±1.61 months) (P<0.001). The frequency of stage 4 MH was significantly higher in eyes with non-stellate appearance (P<0.001). Anatomical correction of MH was achieved in 91.3% (21/23) of eyes with stellate appearance and 71.4% (5/7) of eyes without this appearance (P=0.225).CONCLUSION: Stellate appearance in FAF is associated with earlier stages of macular hole, better visual acuity at presentation, shorter duration of symptoms, thus more favorable prognosis.     

Multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) and antibacterial resistance profiles of extended spectrum beta lactamase (ESBL) producing Pseudomonas aeruginosa among burnt patients in Tehran

Extended spectrum β-lactamase (ESBL)-producing trait was present in 48 out of the 112 (42.8%) Pseudomonas aeruginosa isolates collected from burn wound infections during a 12-month period. The presence of oxa-10, per-1, veb-1 and ges genes and the multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) of 112 P. aeruginosa strains were determined by PCR and multiplex PCR. Disk diffusion methods were used to determine the susceptibility of the isolates to antimicrobial agents as instructed by CLSI. All ESBL isolates were resistant to aztreonam, cefepime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone and ofloxacin. Fewer than 60% of ESBL isolates were resistant to imipenem, meropenem, and piperacillin-tazobactam but more than 90% were resistant to amikacin, ciprofloxacin, levofloxacin, ticarcillin and tobramycin. The most prevalent ESBL genes included oxa-10 (70%) and per-1 (50%) followed by veb-1 (31.3%). The gene encodes GES enzyme did not detect in any isolates. A total of 100 P. aeruginosa strains were typed by MLVF typing method. MLVF produced 42 different DNA banding patterns. These data indicate that different MLVF types infect burn wounds in patients at a hospital in Tehran and also suggest an alarming rate of ESBL-producing isolates in this test location.     

Effect of reversible inactivation of reuniens nucleus on memory processing in passive avoidance task

The reuniens nucleus (RE) is the largest nucleus of the midline thalamic nuclei (MLN). RE has strongly connections with the amygdala and hippocampus, the structures that are involved in the learning and memory processes. In our previous report we have shown the role of RE in the spatial learning and memory using Morris water maze (MWM) task. Since RE is connected to multiple limbic structures, its involvement in the emotional learning and memory is a possibility. The present study was designed to elucidate the role of RE in acquisition, consolidation, and retrieval on the passive avoidance (PA) task which depends on a distributed network including the thalamus, amygdala, medial prefrontal cortex (mPFC) and hippocampus. For this purpose, rats were chronically implanted with a cannula aimed at the RE through which 0.5 μl tetracaine (2%) or saline were injected. Rats were trained in a PA task and their retention test was performed 24 h later. The injection of saline or tetracaine was applied 5 min before or 5, 90, and 360 min after the acquisition trial and 5 min before the retention tests. Our findings showed that inactivation of RE before training did not affect acquisition, but affected memory retention 24 h later in PA task. Moreover, inactivation of RE only 5 min after training impaired consolidation but not after 90 or 360 min. Also, inactivation of the RE, 5 min before the retrieval test impaired memory retrieval in PA task. In conclusion, it seems that RE is involved in memory processes in rats.     

Morphine-induced modulation of LTD at GABAergic synapses in the ventral tegmental area

Adaptive behaviors often require the learning of appropriate responses to rewarding stimuli, yet aberrant learning processes can lead to serious diseases such as addiction. Dopamine (DA) neurons of the ventral tegmental area (VTA) play an essential role in the treatment of rewarding stimuli, and they exhibit plasticity in response to such stimuli, but also to drugs of abuse. Previously we discovered a form of presynaptic nitric oxide (NO)-mediated long-term potentiation (LTP_GABA) at GABAergic synapses onto VTA DA neurons that is prevented with morphine in vivo 24 h after exposure. Here we investigated whether the same GABAergic synapses are capable of exhibiting long-term depression (LTD in addition to LTP_GABA) and its possible modulation by morphine in vivo. We found that indeed the efficacy of VTA GABAergic synapses can be down-regulated through induction of a novel form of LTD (i.e., LTD_GABA) in response to synaptic stimulation. Paired pulse ratio (PPR) and coefficient of variance (CV) analyses of evoked IPSCs confirmed that this plasticity may be postsynaptic. Consistently, LTD_GABA did not involve presynaptic cannabinoid CB₁receptors (CB₁Rs). Moreover, NMDAR activation was not necessary for LTD_GABA. However, blockade of D₂ dopamine receptors (D₂R) significantly attenuated LTD_GABA proposing a novel synaptic mechanism for the regulation of excitability of DA neurons by endogenous DA and D₂R activation. Interestingly, 24 h after a single in vivo exposure to morphine, LTD_GABA was absent in slices from morphine-treated rats but unaffected in slices from saline-treated rats, confirming a bidirectional impact of morphine on GABAergic synaptic plasticity in the VTA. The control of bidirectional GABAergic plasticity by morphine in the VTA may represent the neural correlates necessary for the addictive properties of opiates.This article is part of a Special Issue entitled ‘Synaptic Plasticity and Addiction’.     

The potential utility of fibrin sealant dressing in repair of vascular injury in swine

BACKGROUND: A previous study in which fibrin sealant dressing (FSD) secured hemostasis in major arterial hemorrhage for 96 hours suggested the applicability of this dressing in damage control operations after severe trauma. The objective of this study was to determine the effective duration of FSD hemostatic function in vivo and to examine its potential utility for definitive repair of a major arterial injury in swine. METHODS: High pressure bleeding in an infrarenal aortotomy was controlled by placing FSD on the wound with 4-minute compression (n = 15). If hemostasis was achieved, the abdominal cavity was closed. Surviving animals were killed at 2, 4, 6, and 8 weeks and aortotomy sites collected for histology. RESULTS: FSD stopped arterial hemorrhage after 4-minute compression in 14 of 15 (93%) pigs. Dressings failed in two pigs at 36 and 53 minutes after treatment. Twelve (80%) animals recovered and resumed normal activities. Of the remaining 12, two developed rebleeding at the aortotomy site on days 8 and 11 and were killed; another was killed because of idiopathic low hematocrit on day 10. Nine pigs survived until scheduled to be killed, maintaining hemostasis with stable hematological values. In the surviving animals, serial computed tomography scans showed formation of a pseudoaneurysm at the aortotomy site, which resolved after 2 to 3 weeks. The initial vascular defect and pseudoaneurysm were filled with fibroblast-myoblast collagen rich tissues covered by endothelium. CONCLUSION: FSD can seal an arterial injury, stop high pressure bleeding, and prevent rebleeding for at least 7 days. The dressing may be most beneficial in damage control operations. If combined with an elective interventional radiologic procedure (e.g. embolization or stenting), it may also offer an alternative to suture repair of vascular injuries in cases where profuse bleeding obstructs visualization.