Antiobiotic resistance pattern of biofilm-forming uropathogens isolated from catheterised patients in Pondicherry,India

Background

Microbial biofilms pose a public health problem for persons requiring indwelling medical devices, as micro-organisms in biofilms are difficult to treat with antimicrobial agents. Thus the present study includes biofilm formation and antibiotic resistance pattern of uropathogens in hospitalised patients with catheter associated urinary tract infections (UTI).

Method

This prospective analysis included 100 urine samples from catheterised patients with symptoms of UTI over a period of six months. Following identification, all isolates were subjected to antibiotic sensitivity using modified Kirby- Bauer disc diffusion method. Detection of biofilms was done by tube adherence method and Congo red agar method.

Results

E.coli was found to be the most frequently isolated uropathogen 70%, followed by Klebsiella pneumoniae 16%, Pseudomonas aeruginosa 4%, Acinetobacter spp 2%, coagulase negative Staphylococci 6% and Enterococci Spp 2%. In the current study 60% of strains were in vitro positive for biofilm production. Biofilm positive isolates showed 93.3%, 83.3%, 73.3% and 80% resistance to nalidixic acid, ampicillin, cephotaxime and cotrimoxazole, respectively, compared to 70%, 60%, 35%, 60% resistance showed by biofilm non-producers for the respective antibiotics. Approximately 80% of the biofilm producing strains showed multidrug resistant phenotype

Conclusion

To conclude E.coli was the most frequent isolate, of which 63% were biofilm producers. The antibiotic susceptibility pattern in the present study showed quinolones were the least active drug against uropathogens. The uropathogens showed the highest sensitivity to carbapenems. The next best alternatives were aminoglycosides. Significant correlation between biofilm production and multi-drug resistance was observed in our study.     

Microvesicle-associated AAV Vector as a Novel Gene Delivery System

Adeno-associated virus (AAV) vectors have shown remarkable efficiency for gene delivery to cultured cells and in animal models of human disease. However, limitations to AAV vectored gene transfer exist after intravenous transfer, including off-target gene delivery (e.g., liver) and low transduction of target tissue. Here, we show that during production, a fraction of AAV vectors are associated with microvesicles/exosomes, termed vexosomes (vector-exosomes). AAV capsids associated with the surface and in the interior of microvesicles were visualized using electron microscopy. In cultured cells, vexosomes outperformed conventionally purified AAV vectors in transduction efficiency. We found that purified vexosomes were more resistant to a neutralizing anti-AAV antibody compared to conventionally purified AAV. Finally, we show that vexosomes bound to magnetic beads can be attracted to a magnetized area in cultured cells. Vexosomes represent a unique entity which offers a promising strategy to improve gene delivery.     

Modulation of humoral immune responses and inhibition of proinflammatory cytokines and nitric oxide production by 10-methoxycanthin-6-one

Plant-derived natural products such as alkaloids, flavonoids, terpenoids, and polysaccharides have received considerable attention in recent years due to their diverse pharmacological properties such as immunomodulatory, anti-inflammatory, cytotoxic, cancer chemopreventive effects, and so on. 10-Methoxycanthin-6-one, a β-carboline alkaloid from the medicinal plant Aerva lanata, was assessed for immunomodulatory activity in Balb/c mice. Intraperitoneal administration of five doses of the compound at 0.5?mg/kg body weight was found to enhance the total WBC count (13,975.50?±?324.27 cells/mm3 on the 12th day), bone marrow cellularity (23.08?±?0.86?×?10? cells/femur), and number of α-esterase-positive cells (1283.16?±?21.10 cells/4000 cells). Treatment with the compound along with the antigen, sheep red blood cells, produced an enhancement in the circulating antibody titer (1024 on Days 12 and 15) and the number of plaque-forming cells (PFC) in the spleen. In treated group, maximum number of PFC (264.83 PFC/10? spleen cells) was observed on the sixth day after antigen administration. At the same time, administration of 10-methoxycanthin-6-one could significantly reduce the elevated levels of proinflammatory cytokines and nitric oxide production by lipopolysaccharide (LPS)-stimulated macrophages. There was also a significant reduction in the mRNA levels of inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor alpha (TNF)-α, and interleukin (IL)-1β and IL-6 in LPS-stimulated macrophages after treatment with 10-methoxycanthin-6-one.     

Influence of Modified Posterior Reconstruction of the Rhabdosphincter on Early Recovery of Continence and Anastomotic Leakage Rates after Robot-Assisted Radical Prostatectomy

Background

Posterior reconstruction (PR) of the rhabdosphincter has been previously described during retropubic radical prostatectomy, and shorter times to return of urinary continence were reported using this technical modification. This technique has also been applied during robot-assisted radical prostatectomy (RARP); however, contradictory results have been reported.

Objective

We describe here a modified technique for PR of the rhabdosphincter during RARP and report its impact on early recovery of urinary continence and on cystographic leakage rates.

Design, setting, and participants

We analyzed 803 consecutive patients who underwent RARP by a single surgeon over a 12-mo period: 330 without performing PR and 473 with PR.

Surgical procedure

The reconstruction was performed using two 6-in 3-0 Poliglecaprone sutures tied together. The free edge of the remaining Denonvillier's fascia was identified after prostatectomy and approximated to the posterior aspect of the rhabdosphincter and the posterior median raphe using one arm of the continuous suture. The second layer of the reconstruction was then performed with the other arm of the suture, approximating the posterior lip of the bladder neck and vesicoprostatic muscle to the posterior urethral edge.

Measurements

Continence rates were assessed with a self-administrated, validated questionnaire (Expanded Prostate Cancer Index Composite) at 1, 4, 12, and 24 wk after catheter removal. Continence was defined as the use of “no absorbent pads.” Cystogram was performed in all patients on postoperative day 4 or 5 before catheter removal.

Results and limitations

There was no significant difference between the groups with respect to patient age, body mass index, prostate-specific antigen levels, prostate weight, American Urological Association symptom score, estimated blood loss, operative time, number of nerve-sparing procedures, and days with catheter. In the PR group, the continence rates at 1, 4, 12, and 24 wk postoperatively were 22.7%, 42.7%, 91.8%, and 96.3%, respectively; in the non-PR group, the continence rates were 28.7%, 51.6%, 91.1%, and 97%, respectively. The modified PR technique resulted in significantly higher continence rates at 1 and 4 wk after catheter removal (p = 0.048 and 0.016, respectively), although the continence rates at 12 and 24 wk were not significantly affected (p = 0.908 and p = 0.741, respectively). The median interval to recovery of continence was also statistically significantly shorter in the PR group (median: 4 wk; 95% confidence interval [CI]: 3.39–4.61) when compared to the non-PR group (median: 6 wk; 95% CI: 5.18–6.82; log-rank test, p = 0.037). Finally, the incidence of cystographic leaks was lower in the PR group (0.4% vs 2.1%; p = 0.036). Although the patients’ baseline characteristics were similar between the groups, the patients were not preoperatively randomized and unknown confounding factors may have influenced the results.

Conclusions

Our modified PR combines the benefits of early recovery of continence reported with the original PR technique with a reinforced watertight closure of the posterior anastomotic wall. Shorter interval to recovery of continence and lower incidence of cystographic leaks were demonstrated with our PR technique when compared to RARP with no reconstruction.     

Delineating the roles of the GPIIb/IIIa and GP-Ib-IX-V platelet receptors in mediating platelet adhesion to adsorbed fibrinogen and albumin

Platelet adhesion to adsorbed plasma proteins, such as fibrinogen (Fg), has been conventionally thought to be mediated by the GPIIb/IIIa receptor binding to Arg-Gly-Asp (RGD)-like motifs in the adsorbed protein. In previous studies, we showed that platelet adhesion response to adsorbed Fg and Alb was strongly influenced by the degree of adsorption-induced protein unfolding and that platelet adhesion was only partially blocked by soluble RGD, with RGD-blocked platelets adhering without activation. Based on these results, we hypothesized that in addition to the RGD-specific GPIIb/IIIa receptor, which mediates both adhesion and activation, a non-RGD-specific receptor set likely also plays a role in platelet adhesion (but not activation) to both Fg and albumin (Alb). To identify and elucidate the role of these receptors, in addition to GPIIb/IIIa, we also examined the GPIb-IX-V receptor complex, which has been shown to mediate platelet adhesion (but not activation) in studies by other groups. The platelet suspension was pretreated with either a GPIIb/IIIa-antagonist drug Aggrastat(?) or monoclonal antibodies 6B4 or 24G10 against GPIb-IX-V prior to adhesion on Fg- and Alb-coated OH- and CH(3)-functionalized alkanethiol self-assembled monolayer surfaces. The results revealed that GPIIb/IIIa is the primary receptor set involved in platelet adhesion to adsorbed Fg and Alb irrespective of their degree of adsorption-induced unfolding, while the GPIb-IX-V receptor complex plays an insignificant role. Overall, these studies provide novel insights into the molecular-level mechanisms mediating platelet interactions with adsorbed plasma proteins, thereby assisting the biomaterials field develop potent strategies for inhibiting platelet-protein interactions in the design of more hemocompatible cardiovascular biomaterials and effective anti-thrombotic therapies.