Detection of VEB-1, OXA-10 and PER-1 genotypes in extended-spectrum β-lactamase-producing Pseudomonas aeruginosa strains isolated from burn patients

Resistance of Pseudomonas aeruginosa strains to the broad-spectrum cephalosporins may be mediated by the extended-spectrum β-lactamases (ESBLs). These enzymes are encoded by different genes located on either chromosomes or plasmids. This study aimed to investigate the prevalence of ESBLs and antimicrobial susceptibilities of P. aeruginosa isolated from burn patients in Tehran, Iran. Antimicrobial susceptibility of 170 isolates to cefpodoxime, aztreonam, ciprofloxacin, ofloxacin, ceftazidime, cefepime, imipenem, meropenem, cefotaxime, levofloxacin, piperacillin–tazobactam and ceftriaxone was determined by disc agar diffusion test. Polymerase chain reaction (PCR) amplification of the genes encoding OXA-10, PER-1 and VEB-1 was also performed. All isolates (100%) were resistant to ceftazidime, cefotaxime, cefepime and aztreonam. Imipenem and meropenem were the most effective anti-pseudomonal agents. The results revealed that 148 (87.05%) of the isolates were multidrug resistant and 67 (39.41%) of the isolates were ESBL positive. Fifty (74.62%), 33 (49.25%) and 21 (31.34%) strains among 67 ESBL-producing strains amplified bla_OXA-10, bla_PER-1 and bla_VEB-1 respectively.     

Molecular characterization of CTX-Mβ-lactamases among Klebsiella pneumoniae isolated from patients at Tehran hospitals

Purpose: Plasmid-encoded CTX-M-group of extended-spectrum β-lactamases (ESBLs) represent a significant and rapidly emerging problem in most part of the world. The aim of the present study was to describe the prevalence of CTX-M producing Klebsiella pneumoniae at Tehran hospitals. Materials and Methods: Clinical isolates of K. pneumoniae (n=250) were collected from 10 hospitals of Tehran. Susceptibility to antimicrobial agents, MIC of cefotaxime and ESBLs production of collected isolates were detected. All ESBL-producing isolates were screened for bla_CTX-M genes using PCR and DNA sequencing. Molecular typing of bla_CTX-M harboring isolates was performed by Pulsed–field gel electrophoresis assay. Results: Of 250 K. pneumoniae clinical isolates, 102 isolates revealed ESBLs – phenotype. PCR assay and sequencing detected bla_CTX-M genes in 71.5% (n= 73) of ESBL-producing isolates. The prevalence of CTX-M -I and CTX-M-III clusters among these isolates was 35.61% (n=26) and 21.9 % (n=16) respectively. Coexistence of CTX-M -I and CTX-M-III clusters was found among 42.5% (n= 31) of isolates. Of 102 isolates that were positive in the phenotypic confirmatory test (PCT), 29 isolates (28.4%) did not produce any amplicons in PCR for bla_CTX-M gene. The results of PCR for CTX-M -II and CTX-M-IV clusters were also negative. Analysis of the 31 CTX-M producing K. pneumoniae isolates by PFGE typing showed 26 distinct patterns. Conclusions: The bla_CTX-M genes are widespread among Iranian isolates of K. pneumoniae. PFGE demonstrated the high diversity of K. pneumoniae harboring bla_CTX-M in our study.     

Chronic typhoid infection and the risk of biliary tract cancer and stones in Shanghai,China

Previous studies have shown a positive association between chronic typhoid carriage and biliary cancers. We compared serum Salmonella enterica serovar Typhi antibody titers between biliary tract cancer cases, biliary stone cases without evidence of cancer, and healthy subjects in a large population-based case-control study in Shanghai, China.     

Effect of chlorhexidine application on long-term shear bond strength of resin cements to dentin

PurposeThe purpose of this study was to investigate the effect of chlorhexidine [CH] on dentin bond strength of three resin cements after 1 year of water storage.MethodsA flat middle dentin surface was prepared on 120 extracted premolars. The teeth were randomly divided into 6 groups of 20 specimens each according to the resin cement used: Panavia F2.0, Variolink II, and RelyX Unicem, with or without CH application. After cementation of an indirect composite rod [Z250], one subgroup [n = 10] was tested after 24 h in water at 37 °C and the other subgroup [n = 10] was tested after 1 year storage in water plus thermocycling. A shear bond strength [SBS] test was performed. The data [in MPa] were analyzed with ANOVA and Tukey tests [P < 0.05].ResultsThree-way ANOVA [resin cement, CH and time] indicated that Variolink II had the highest strength [16.65 ± 3.60] and RelyX Unicem had the lowest strength [9.30 ± 4.07]. Chlorhexidine application increased SBS [13.31 ± 4.61] compared to samples without CH [12.16 ± 5.04] [P = 0.04]. Initial SBS [15.63 ± 4.37] was significantly higher than after 1 year of storage [9.85 ± 3.36] [P < 0.001]. Separate two-way ANOVA for 24-h and 1-year data showed that cement had a significant effect but CH and its interaction had no significant effect at 24 h, whereas at 1 year the two factors and their interaction differed significantly [P ≤ 0.001].ConclusionsChlorhexidine 2% can diminish the loss of bonding effectiveness over time associated to etch-and-rinse and self-etch cements, although it appears not have any effect on self-adhesive cement.     

Hypnotherapy in management of pain and reexperiencing of trauma in burn patients

This study examined the effects of hypnosis on both pain and reexperiencing of trauma in burn patients. Forty-four patients hospitalized for burn care were randomly assigned to either hypnotherapy or a control group. Direct and indirect hypnotic suggestions were used to reduce pain and reexperiencing of trauma. All patients received routine burn care. Pain reports were quantified by using a self-report numeric rating scale ranging from 0 to 5. The number of recalled vivid, troubling events of the trauma in 24-hour intervals was used for rating the reexperiencing of trauma. The hypnotherapy group showed significantly lower pain ratings than the control group and reported a significant reduction in pain from baseline. There was a significant reduction in trauma reexperience scores in the hypnotherapy group but not the control group. The findings support the efficacy of hypnotherapy in the management of both pain and reexperiencing of trauma in burn patients.     

Effect of parental morphine addiction on hippocampal long-term potentiation in rats offspring

Attention to addiction of women alone for fetus and infant's health has caused the possible role of father's status was less considered, while some developmental impairments including decrease of liter size, weight loss, congenital deficiencies, behavioral disorders, and learning and memory impairments in offspring with addicted father have been reported. In this study the effects of addiction of one or both parents to morphine on male and female offspring hippocampal long-term potentiation (LTP), were assessed. One hundred twenty female and 48 male rats (4-5 months, 250-270 g) were used. Forty females and 16 males were addicted by oral administration of morphine (32 mg/kg twice daily) for 5 days before mating. Then each two males with five females were housed (coupled) per cage as five groups for coupling: (A) addicted females+5% dextrose males (add.F); (B) addicted males+5% dextrose females (add.M); (C) addicted females+addicted males (add.MF); (D) 5% dextrose females+intact males (dex.F); (E) 5% dextrose males+intact females (dex.M). In puberty offspring LTP was induced in hippocampal dentate gyrus by stimulation of perforant path (pp). Changes of population spikes (PS) amplitude and LTP slope at 0, 5, 30, 60 and 120 min were evaluated. Slope of LTP at 30, 60 and 120 min, and amplitude of PS at 60 and 120 min in add.F and add.M offspring were significantly lower than dextrose groups (P<0.01). LTP slope and PS amplitude of male and female offspring did not different between add.F and add.M groups. Our results suggest that both parental and paternal addiction to morphine may cause memory deficiency through reduction of LTP in hippocampus.     

Nifedipine suppresses morphine-induced thermal hyperalgesia: evidence for the role of corticosterone

It has been shown that systemic administration of morphine induced a hyperalgesic response at an extremely low dose. We have examined the effect of nifedipine, as a calcium channel blocker, on morphine-induced hyperalgesia in intact and adrenalectomized rats and on hypothalamic-pituitary-adrenal axis activity induced by ultra-low dose of morphine. To determine the effect of nifedipine on hyperalgesic effect of morphine, nifedipine (2 mg/kg i.p. and 10 microg i.t.) that had no nociceptive effect, was injected concomitant with morphine (1 microg/kg i.p. and 0.01 microg i.t. respectively). The tail-flick test was used to assess the nociceptive threshold, before and 30, 60, 120, 180, 240 and 300 min after drug administration. The data showed that low dose morphine systemic administration could produce hyperalgesic effect in adrenalectomized rats equivalent to sham-operated animals while intrathecal injection of morphine only elicited hyperalgesia in sham-operated animals. Nifedipine could block morphine-induced hyperalgesia in sham and adrenalectomized rats and even a mild analgesic effect was observed in the adrenalectomized group which was reversed by corticosterone replacement. Systemic administration of low dose morphine produced significant increase in plasma level of corticosterone. Nifedipine has an inhibitory effect on morphine-induced corticosterone secretion. Thus, the data indicate that dihydropyridine calcium channels are involved in ultra-low dose morphine-induced hyperalgesia and that both the pattern of morphine hyperalgesia and the blockage of it by nifedipine are modulated by manipulation of the hypothalamic pituitary adrenal axis.     

Effect of Resin Coating and Chlorhexidine on the Microleakage of Two Resin Cements after Storage

Purpose: This study evaluated the effect of resin coating and chlorhexidine (CH) on microleakage of two resin cements (Panavia F2.0, Nexus 2) after water storage. Materials and Methods: Class V cavities were prepared on the facial and lingual surfaces of 120 intact human molars with gingival margins placed 1 mm below the cementoenamel junction. Indirect composite inlays were fabricated. The specimens were randomly assigned into six groups (n = 40). Indirect composite inlays (Gradia) were cemented as follows: Group 1 (control): inlays were cemented with Panavia F2.0 according to the manufacturer's instructions. Group 2: the ED‐primed (ED Primer, Kuraray Dental, Tokyo, Japan) dentin was coated with a resin layer before cementation of the inlays with Panavia F2.0. Group 3: a 2% CH solution was applied before bonding with Panavia F2.0. Group 4: after CH application, the primed dentin was coated with a resin layer before cementation with Panavia F2.0. Group 5: (control) after applying Optibond Solo Plus, the inlays were cemented with Nexus 2. Group 6: after etching, CH was applied, and cementation was performed similarly to group 5. Half the specimens in each group were stored in distilled water for 24 hours, while the other half were stored in distilled water for 6 months. After storage, the teeth were placed in 1% methylene blue dye for 24 hours, sectioned, and evaluated under a 20× stereomicroscope. Dye penetration was scored using 0 to 3 criteria. Data were analyzed using nonparametric tests. Results : Resin coating of ED primer for Panavia F2.0 significantly reduced microleakage at the gingival margins after 6 months (p < 0.05). CH application in Panavia F2.0 did not lead to a significant difference in the microleakage at both margins, after 24 hours and 6 months (p > 0.05). The application of CH showed significantly less microleakage than that of the control group at the gingival margins of Nexus 2 after 6 months. In general, gingival margins showed more microleakage than occlusal margins. Conclusion: An additional resin layer applied to a self‐etch cement can improve long‐term dentinal sealing for indirect restorations, while CH cannot; however, CH reduces gingival microleakage in an etch‐and‐rinse cement after aging.