Spread of OXA-48-Encoding Plasmid in Turkey and Beyond

Eighteen carbapenem-resistant, OXA-48-positive enterobacterial isolates recovered from Turkey, Lebanon, Egypt, France, and Belgium were analyzed. In most isolates, similar 70-kb plasmids carrying the carbapenemase gene bla_OXA-48 were identified. That gene was located within either transposon Tn1999 or transposon Tn1999.2, which was always inserted within the same gene. This work highlights the current plasmid-mediated dissemination of the OXA-48 carbapenemase worldwide.Carbapenem-hydrolyzing β-lactamases belonging to Ambler classes A, B, and D have been reported worldwide among Enterobacteriaceae (22). The extensive spread of Ambler class A carbapenemases of the KPC type highlights that carbapenemases may rapidly become threatening (17). Acquired class D ß-lactamases possessing carbapenemase properties have been reported previously, being identified mainly in Acinetobacter sp. (18, 21) and occasionally in Enterobacteriaceae. The chromosome-encoded oxacillinase OXA-23 was previously described for Proteus mirabilis (4), and the oxacillinase OXA-48 was first identified in a Klebsiella pneumoniae isolate from Turkey (20). Since then, several other OXA-48-producing isolates of various enterobacterial species (Citrobacter freundii and Escherichia coli) have been reported, mainly from Turkey (1, 6, 11, 16) but also from Belgium (8), from Lebanon (15), and more recently from the United Kingdom (14, 23a), India (3a), and Argentina (6a). So far, the bla_OXA-48 gene has been found to be plasmid borne and located between two identical insertion sequences, IS1999, forming the composite transposon Tn1999 (3). We have analyzed here the genetic backgrounds associated with the bla_OXA-48 gene among Enterobacteriaceae isolates collected from different countries.The study included 18 OXA-48-positive clinical isolates of K. pneumoniae (13 isolates), Enterobacter cloacae (2 isolates), Providencia rettgeri (1 isolate), C. freundii (1 isolate), and E. coli (1 isolate). Isolates were mainly from the Turkish cities Istanbul, Ankara, and Izmir (n = 14) (Table ​(Table1).1). Among the 13 K. pneumoniae isolates, at least Kp11978 (20) and KpB had been sources of nosocomial outbreaks (6). A single K. pneumoniae isolate (KpBEL) was recovered from Brussels, Belgium (8); another K. pneumoniae isolate (KpL) from Beirut, Lebanon (15); another K. pneumoniae isolate from the Bicêtre Hospital (KpBIC), Paris, France (this study); and another K. pneumoniae isolate from Gizah, Egypt (KpE) (8a). Samples were isolated from blood (KpI1, KpI2, KpB, and Enc1), urine (PR, KpBEL, KpL, Kp11978, and KpBIC), cerebrospinal fluid (Enc2), and catheter (KpE). Isolates from Belgium, France, Egypt, and Lebanon were from patients who did not report recent travel history.

TABLE 1.

MICs of β-lactams for the 18 isolates of Enterobacteriaceae and their transconjugants and/or transformants (pOXA-48) E. coli J53 and E. coli TOP10

Grape seed extract treatment reduces hepatic ischemia-reperfusion injury in rats

This study was designed to determine the possible protective effect of grape seed extract (GSE), a widely used antioxidant dietary supplement, on hepatic ischemia/reperfusion (I/R) injury. Wistar albino rats were subjected to 45 min of hepatic ischemia, followed by a 60 min reperfusion period. GSE was administered in a dose of 50 mg/kg/day orally for 15 days before I/R injury and repeated before the reperfusion period. Liver samples were taken for histological examination or determination of hepatic malondialdehyde (MDA), glutathione (GSH) and myeloperoxidase (MPO) activity. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were determined to assess liver functions. Lactate dehydrogenase (LDH) and cytokines (TNF-alpha and IL-1 beta) were also assayed in serum samples for the evaluation of generalized tissue damage. Ischemia/reperfusion caused a significant decrease in hepatic GSH, and significant increases in MDA level, and MPO activity. Serum AST and ALT levels, as well as LDH activity and plasma TNF-alpha and IL-1beta levels were also elevated in the I/R group. Treatment with GSE reversed all these biochemical parameters as well as histological alterations induced by I/R. In conclusion, GSE reduced I/R-induced organ injury through its ability to balance the oxidant-antioxidant status, to inhibit neutrophil infiltration and to regulate the release of inflammatory mediators.     

Cognitive impairment patterns in Parkinson's disease with visual hallucinations.

OBJECTIVES: We investigated the role of stage of disease, motor status and dopaminergic treatment in cognitive impairment of Parkinson's disease (PD) patients with visual hallucination (VH) and the presence of specific cognitive impairment patterns. METHOD: We compared 33 PD patients with VH (group 1) with 30 PD patients without VH (group 2) with regard to demographic characteristics and neuropsychological test scores. RESULTS: The group with VH demonstrated significantly worse Short Test of Mental Status scores; the cognitive impairment pattern presented in the form of frontal dysfunction and memory deterioration. There were significant differences in Stroop duration/error, verbal fluency, Wechsler Memory Scale and Sozel Bellek Surecleri Test (a Turkish verbal learning test) scores. CONCLUSION: In PD patients with VH the main pattern of cognitive impairment is frontal dysfunction and memory deterioration. Because visual perceptive functions were not different between the two groups, such deterioration may not be a primary factor in the development of VH.     

Role of melatonin in reducing water avoidance stress-induced degeneration of the gastrointestinal mucosa

We investigated the role of melatonin on water avoidance stress (WAS)-induced degeneration of the gastric, ileal and colonic mucosa. Wistar albino rats were exposed to acute WAS (aWAS group) or chronic WAS (cWAS group). Before exposing animals to acute (aWAS + mel group) or chronic WAS (cWAS + mel group), 10 mg/kg melatonin was injected i.p. The stomach, ileum and colon samples were investigated under light and scanning electron microscope. Malondialdehyde (MDA) and glutathione (GSH) levels were also determined. In both aWAS and cWAS groups, the epithelium of stomach showed ulceration in some areas, dilatations of the gastric glands and degeneration of gastric glandular cells; prominent congestion of the capillaries after WAS was apparent. In the cWAS group, severe vascular congestion was observed along with degeneration of ileal and colonic epithelium. MDA levels were increased and GSH levels were decreased in all tissues in both the aWAS and cWAS groups. The morphology of gastric, ileal and colonic mucosa in both aWAS + mel and cWAS + mel groups showed that the indole significantly reduced degeneration of the gastrointestinal mucosa. Decreased MDA and increased GSH levels were observed in the WAS + mel groups. Based on the results, melatonin treatment significantly prevented WAS induced degenerative morphological and biochemical changes of gastrointestinal mucosa.     

Protective effects of chronic melatonin treatment against renal injury in streptozotocin-induced diabetic rats

The aim of this study was to investigate the effects of melatonin as an antioxidant, on prevention and treatment of streptozotocin (STZ)-induced diabetic renal injury in rats. Male Wistar rats were divided into four groups: (1) untreated, (2) melatonin-treated, (3) untreated diabetic (UD), (4) melatonin-treated diabetic (MD). Experimental diabetes was induced by single dose (60 mg/kg, i.p.) STZ injection. For 3 days prior to administration of STZ, melatonin was injected (200 microg/kg/day, i.p.); these injections were continued until the end of the study (4 weeks). Malondialdehyde (MDA) levels as a marker of lipid peroxidation were significantly increased in the renal homogenates of UD animals and decreased after melatonin administration. The activity of the antioxidative enzyme glutathione peroxidase (GSH-Px) was significantly reduced in UD rats. Melatonin treatment reversed STZ-induced reduction of GSH-Px activity without having an effect on blood glucose. Upon histopathological examination, it was observed that the melatonin treatment prevented the renal morphological damage caused by diabetes. Upon immunohistochemical investigation, glomerular anti-laminin beta1 staining decreased in MD rats. Additionally, no tubular anti-IGF-1 staining was observed in melatonin-treated rats. In conclusion, chronically administered melatonin reduced renal injury in STZ-induced diabetic rats and thus it may provide a useful therapeutic option in humans to reduce oxidative stress and the associated renal injury in patients with diabetes mellitus.     

Halofuginone,a Specific Inhibitor of Collagen Type 1 Synthesis,Ameliorates Oxidant Colonic Damage in Rats with Experimental Colitis

To evaluate the effect of halofuginone on trinitrobenzene sulfonic acid (TNBS)-induced colonic injury, rats were given halofuginone (40 μg/kg, intraperitoneally) or saline 1 h before the induction of colitis, and the injections were continued twice daily for 3 days until they were decapitated. High macroscopic and microscopic damage scores, elevated colonic wet weights, colonic myeloperoxidase activity, malondialdehyde and tissue collagen level, and luminol chemiluminescence values, and marked reduction in glutathione level of the saline-treated colitis group were all reversed by treatment with halofuginone. In conclusion, halofuginone exerts beneficial effects in TNBS-induced colonic inflammation in rats. The anti-inflammatory effects of halofuginone appear to involve suppression of neutrophil accumulation, preservation of endogenous glutathione, and inhibition of reactive oxidant generation. Halofuginone also shows antifibrotic effect via inhibition of tissue collagen production. The present data encourage possible use of the antifibrotic halofuginone as an anti-inflammatory agent in improving oxidative injury in colitis.     

Montelukast reduces ischaemia/reperfusion-induced bladder dysfunction and oxidant damage in the rat

The present study aimed to investigate the possible beneficial effects of the cysteinyl leukotriene-1 receptor antagonist montelukast on contractility and oxidant damage after ischaemia/reperfusion (I/R) of rat urinary bladder. The abdominal aorta of Sprague-Dawley rats was occluded to induce I/R. Montelukast (10 mg kg(-1)) or saline was administered intraperitoneally before I/R. In the sham-operated group, the abdominal aorta was left intact and the animals were treated with montelukast or saline. After decapitation, the bladder was removed and the tissue was either used for functional studies or stored for biochemical assays. In the I/R group, the isometric contractile responses of the bladder strips to carbachol (10(-8)-10(-4) M) were lower than those of the control group and were reversed by treatment with montelukast. Lipid peroxidation and myeloperoxidase activity of the bladder tissues in the I/R group were greater than in the sham-operated group. Montelukast treatment in the I/R group decreased these parameters compared with I/R alone. Similarly, the significant decrease in tissue glutathione level in the I/R group compared with controls was also prevented by montelukast. Treatment with montelukast almost completely reversed the low contractile responses of rat urinary bladder to carbachol and prevented oxidative tissue damage following I/R.     

Alpha-lipoic acid protects against hepatic ischemia-reperfusion injury in rats

BACKGROUND AND AIM: To evaluate the protective effect of alpha-lipoic acid in reducing oxidative damage after severe hepatic ischemia/reperfusion (IR) injury. METHODS: Wistar albino rats were subjected to 45 min of hepatic ischemia, followed by 60 min reperfusion period. Lipoic acid (100 mg/kg i.p.) was administered 15 min prior to ischemia and immediately before reperfusion period. At the end of the reperfusion period aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) activity, and cytokine, TNF-alpha and IL-1beta levels were determined in serum samples. Malondialdehyde (MDA), and glutathione (GSH) levels and myeloperoxidase (MPO) activity were determined in the liver tissue samples while formation of reactive oxygen species was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Tissues were also analyzed histologically. Results: Serum ALT, AST, and LDH activities and TNF-alpha and IL-1beta levels were elevated in the I/R group, while this increase was significantly lower in the group of animals treated concomitantly with lipoic acid. Hepatic GSH levels, significantly depressed by I/R, were elevated back to control levels in lipoic acid-treated I/R group. Furthermore, increases in tissue luminol and lucigenin CL, MDA levels and MPO activity due to I/R injury were reduced back to control levels with lipoic acid treatment. CONCLUSION: Since lipoic acid administration alleviated the I/R-induced liver injury and improved the hepatic structure and function, it seems likely that lipoic acid with its antioxidant and oxidant-scavenging properties may be of potential therapeutic value in protecting the liver against oxidative injury due to ischemia-reperfusion.     

Synthesis and characterization of poly(ethylene glycol)-poly(D,L-lactide-co-glycolide) poly(ethylene glycol) tri-block co-polymers modified with collagen: a model surface suitable for cell interaction

This study focused on the synthesis and characterization of poly(ethylene glycol)-poly(D,L-lactide-co-glycolide)-poly(ethylene glycol) tri-block co-polymer (PEG-PDLLG-PEG), and its modification with type-I collagen. To this aim, a PEG-PDLLG-PEG tri-block co-polymer was synthesized in two steps by reacting poly(ethylene glycol)bis(carboxymethyl)ether with thionyl chloride to obtain an acyl-halide-terminated poly(ethylene glycol) and subsequently coupling this compound to hydroxyl-terminated poly(D,L-lactide-co-glycolide) (PDLLG). The new carboxyl endgroups of PEG-PDLLG-PEG were subsequently reacted with N-hydroxysuccinimide (NHS) in the presence of the hetero-bifunctional cross-linking agent dicyclohexylcarbodiimide (DCC) in order to activate the co-polymer for coupling with collagen. PEG-PDLLG-PEG and its activated form PEG-PDLLG-NHS were characterized by Fourier transform infrared (FT-IR) and 1H-NMR spectroscopy. Molecular weights of the polymeric products were determined by SEC. Type-I collagen in phosphate buffer was reacted with PEG-PDLLG-NHS. The resultant product, PEG-PDLLG-Col, was characterized by FT-IR. This biopolymer was used for preparation of a suitable surface for cell growth experiment. To measure the degree of cell proliferation, the films prepared with PDLLG, PEG-PDLLG-NHS and PEG-PDLLG-Col were seeded with L929 mouse fibroblasts. Cell growth was followed by SEM photography and quantitated by the neutral red uptake assay. It was shown that the attachment of collagen significantly increased the number of cells on the co-polymers.