Emergence of ciprofloxacin-resistant pseudomonas in pediatric otitis media

Controlled release of ciprofloxacin and ceftriaxone from a single ototopical administration of antibiotic-loaded polymer microspheres and thermoresponsive gel

Acute otitis media (AOM) is the main indication for pediatric antibiotic prescriptions, accounting for 25% of prescriptions. While the use of topical drops can minimize the administered dose of antibiotic and adverse systemic effects compared to oral antibiotics, their use has limitations, partially due to low patient compliance, high dosing frequency, and difficulty of administration. Lack of proper treatment can lead to development of chronic OM, which may require invasive interventions. Previous studies have shown that gel-based drug delivery to the ear is possible with intratympanic injection or chemical permeation enhancers (CPEs). However, many patients are reluctant to accept invasive treatments and CPEs have demonstrated toxicity to the tympanic membrane (TM). We developed a novel method of delivering therapeutics to the TM and middle ear using a topical, thermoresponsive gel depot containing antibiotic-loaded poly(lactic-co-glycolic acid) microspheres. Our in vitro and ex vivo results suggest that the sustained presentation can safely allow therapeutically relevant drug concentrations to penetrate the TM to the middle ear for up to 14 days. Animal results indicate sufficient antibiotic released for treatment from topical administration 24h after bacterial inoculation. However, animals treated 72h after inoculation, a more clinically relevant treatment practice, displayed spontaneous clearance of infection as is also often observed in the clinic. Despite this variability in the disease model, data suggest the system can safely treat bacterial infection, with future studies necessary to optimize microsphere formulations for scaled up dosage of antibiotic as well as further investigation of the influence of spontaneous bacterial clearance and of biofilm formation on effectiveness of treatment. To our knowledge, this study represents the first truly topical drug delivery system to the middle ear without the use of CPEs.

A newly designed tympanostomy stent with TiO2 coating to reduce Pseudomonas aeruginosa biofilm formation

Biofilm formation has been implicated as a cause of post-tympanostomy tube otorrhea in patients suffering from otitis media with effusion, and biofilms have been found to adhere to all available types of tympanostomy tubes (TT) made from silicone. In this study, we present a novel stent designed with a reduced surface area and a titanium dioxide (TiO2) coating to prevent biofilm formation. Using a radio frequency power supply, tympanostomy stents (TS) made from Nitinol (Nikel-titanium) were coated with TiO2 to form an oxide layer on the metallic target. We successfully reproduced biofilms with carbenicillin-resistant Pseudomonas aeruginosa strain, PAO1-GFP (green fluorescent protein) on the tubes in vitro. We then compared the levels of biofilm formation by this strain on the two types of implants using several methods, including bacterial quantification, electron microscopy, and confocal laser fluorescent microscopy. Our results provide definitive evidence that the combination of the TiO2 coating and minimized surface area of the Nitinol stent inhibited the P. aeruginosa biofilm formation. The ability of the TS to prevent viable bacteria colonization (over 10 folds, compared to silicone TT) was verified by anti-biofilm test. Future studies will reveal more useful in reducing otorrhea and plugging complications as a novel tympanostomy tube.

Pseudomonas aeruginosa biofilms: mechanisms of immune evasion

The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.

Optimising the pre-treatment process before mobile ear surgery for chronic suppurative otitis media in Wolisso and Attat, Ethiopia

Background:

Chronic suppurative otitis media is a major cause of long-standing hearing impairment in many Sub-Saharan African countries.

Methods:

Attempts were made to optimise the pre-treatment process before mobile ear surgery for chronic suppurative otitis media in Wolisso, a semi-urban community in the Oromia region, and in Attat, a rural community in the Gurage region, both in the south-west of Ethiopia, between 2008 and 2010. This included special training for ENT nurses, and the use of a strict scheduling regime and improved topical treatment.

Results and conclusion:

This strategy allowed effective middle-ear surgery to be carried out using simple means and with a mobile ear surgery team, the latter of which is only transiently but regularly on site.

Effect of ion-bombarded silicone tympanostomy tube on ciprofloxacin-resistant Pseudomonas aeruginosa biofilm formation

OBJECTIVES

Many materials and surface preparations have been developed to resist the formation of biofilm. Ion-bombarded silicone tympanostomy tube was introduced to resist both staphylococcal and pseudomonal biofilm formation. To date, there are no reports that have evaluated the use of ion-bombarded tympanostomy tubes against the ciprofloxacin-resistant Pseudomonas aeruginosa (CRPA) biofilm formation. The purpose of this study is to evaluate the ion-bombarded tympanostomy tube for CRPA biofilm resistance.

METHODS

Commercial ion-bombarded tympanostomy tubes and simple silicone tympanostomy tubes were processed for an evaluation of the CRPA biofilm formation in vitro.

RESULTS

The ion-bombarded tubes showed no resistance to CRPA adhesion and biofilm formation. Thick and dense conglomeration was less formed in the ion-bombarded tympanostomy tubes, compared to that of the simple silicone tube.

CONCLUSION

The preventive effect against the CRPA biofilm formation of the ion-bombarded silicone tympanostomy tube was not observed. Our result suggests that only the surface modification by an ion bombardment is not enough to resist CRPA biofilm formation.

Resistance pattern of ciprofloxacin against different pathogens

OBJECTIVES

Ciprofloxacin is a broad-spectrum antibiotic widely prescribed in clinical and hospital settings. The emergence of antimicrobial resistance against effective antibiotics is a global issue. The objective of study is the surveillance of ciprofloxacin against common pathogens.

METHODS

To investigate the present status of antimicrobial resistance against ciprofloxacin, five hundred and twenty four clinical isolates of Escherichia coli (30%), Staphylococcus aureus (33%), Salmonella typhi (9%), Klebsiella pneumonia (14%) and Pseudomonas aeruginosa (14%) were collected during study from January, 2008 to February, 2009 from different pathological laboratories running in and out side hospitals located in Karachi, Pakistan. These pathogens were isolated from specimens of both in and out patients. The in-vitro antimicrobial activity of ciprofloxacin was carried out by Disc Diffusion Method (Kirby-Bauer test).

RESULTS

Showed that ciprofloxacin is 27.02%, 21.95%, 16.66%, 72.22% and 44.44% resistant to Escherichia coli, Staphylococcus aureus, Salmonella typhi, Klebsiella pneumonia and Pseudomonas aeruginosa respectively.

CONCLUSION

It is concluded that these clinical isolates have started developing resistance against ciprofloxacin due to its irrational and inappropriate use. Continuous surveillance is crucial to monitor the antimicrobial resistance among pathogens.

Antibiotic resistance and otomycosis in the draining ear: culture results by diagnosis

OBJECTIVE

The objective of the study was to better define changes in the bacteriology of suppurative otitis in recent years and the role of cultures in the management of these patients.

STUDY DESIGN

A retrospective review was performed.

METHODS

Outpatient records from 170 patients collected over 3 years with information regarding the bacteria cultured, antibiotic resistance, and clinical diagnosis were analyzed.

RESULTS

A large variety of organisms were seen, with Staphylococcus aureus, Corynebacterium sp, and Pseudomonas aeruginosa being the most common. Forty percent of cultures showed bacteria with moderate antibiotic resistance, whereas 5% were sensitive to only intravenous antibiotics. Resistant bacteria were found in all diagnosis categories and were significantly higher in cases of chronic mastoiditis. The rate of methicillin-resistant S aureus infections was 7.8% and was significantly higher in cases of chronic myringitis. Fungus was often cultured in patients without clinical signs of otomycosis.

CONCLUSIONS

Community-acquired ear infections may be caused by antibiotic-resistant bacteria in a substantial number of patients. In our opinion, outpatient cultures play an important role in the management of suppurative otitis.

The use of piperacillin-tazobactam coated tympanostomy tubes against ciprofloxacin-resistant Pseudomonas biofilm formation: an in vitro study

BACKGROUND AND OBJECTIVE

Bacterial biofilm formation has been implicated in the high rate of persistent otorrhea after tympanostomy tube insertion. It has been suggested that the tube material may be an important factor in the development of otorrhea. Recently we reported the presence of ciprofloxacin-resistant Pseudomonas aeruginosa (CRPA) biofilms on infected tympanostomy tubes following the use of intractable post-tympanostomy tubes and the onset of otorrhea. In this study, we have evaluated the resistance of piperacillin-tazobactam coated with chitosan on a tympanostomy tube to prevent CRPA biofilm formation in vitro.

MATERIALS AND METHODS

Three sets each of piperacillin-tazobactam coated silicone tubes (n=5), commercial silver-oxide coated silicone tubes (Activent, Silic) (n=5) and control uncoated tympanostomy tubes (Paparella type 1) (n=5) were processed for evaluation. The piperacillin-tazobactam coated tympanostomy tubes were compared with the silver-oxide coated tubes and the uncoated control tubes for resistance to CRPA biofilm formation after in vitro incubation.

RESULTS

Scanning electron microscopy showed that the surface of the silver-oxide coated tube (Activent) formed a thick biofilm with crusts as well as an uncoated tube. In contrast, the surface of a piperacillin-tazobactam coated tympanostomy tube showed virtually no CRPA biofilm formation.

CONCLUSION

The piperacillin-tazobactam coated tympanostomy tube showed resistance to CRPA biofilm formation. The piperacillin-tazobactam coating may be useful to reduce CRPA biofilm formation; however, further in vivo studies are necessary.

Evaluating the ototoxicity of topical piperacillin-tazobactam

BACKGROUND AND OBJECTIVE

With the increased use of ototopical ciprofloxacin solution, newly evolved bacterial fluoroquinolone resistance has also become more of a problem. The emergence of ciprofloxacin-resistant Pseudomonas aeruginosa (CRPA) has created a new therapeutic challenge in otology. We evaluated the ototoxicity of topical fortified piperacillin-tazobactam solution by performing experiments in young male albino guinea pigs (weight, 250-300 g each).

MATERIALS AND METHODS

Antimicrobial assay by direct contact test using scanning electron microscope was performed. Twenty guinea pigs (250-300 g) were treated with fortified piperacillin-tazobactam solution. In experimental group 1 (n=10), a gelfoam ball impregnated with 120 microl of fortified piperacillin-tazobactam was implanted on the round window membrane by a posterior approach. In experimental group 2 (n=10), 20 microl of fortified piperacillin-tazobactam was injected into the middle ear cavity via silicone tube with a small hole placed in the superior aspect of the bulla by drilling. The drug application through the tube was performed for 7 consecutive days. In control group (n=5), a gelfoam ball impregnated with 120 microl of gentamicin solution (80 mg/2 ml) was implanted on the round window membrane.

RESULTS

The fortified piperacillin-tazobactam 20 microl treated CRPAs showed destruction of their cell membrane in antimicrobial assay by direct contact test. No significant difference in the mean auditory brainstem response (ABR) thresholds before and after drug administration was found for the experimental group. However, significant elevation of the mean ABR thresholds was found for the control group. In experimental group, scanning electron microscopy showed almost normal sterociliary arrangements and surface structure on the inner and outer hair cells. However, significant destruction of outer hair cells was identified in control group.

CONCLUSION

This present study's data suggests that fortified piperacillin-tazobactam solution can be effectively used for topically treating CRPA otorrhea in those patients who suffer with chronic suppurative otitis media.

Structural features of tympanostomy tube biofilm formation in ciprofloxacin-resistant Pseudomonas otorrhea

OBJECTIVE

Bacterial biofilm formation has been implicated in the high rate of persistent otorrhea after tympanostomy tube insertion. In this study, we evaluated Pseudomonal biofilm formation from intractable post tympanostomy tube otorrhea in children.

MATERIALS AND METHODS

Twelve patients (seven males, five females) with unilateral post tympanostomy tube P. aeruginosa otorrhea were evaluated prospectively. All patients were treated with ciprofloxacin otic drops but the otorrhea failed to resolve. Ear discharge for culture was collected from the external auditory canal using a swab. The tympanostomy tubes were removed and collected for evaluation of biofilm formation using a scanning electron microscopy.

RESULTS

In all cases, ciprofloxacin-resistant P. aeruginosa was the only organism grown. The surface of the silicone tube contained undulations or microfissures throughout. The thick biofilms present on most tube surfaces were densities with no intervening spaces, consistent with biofilms.

CONCLUSION

Biofilms can be directly observed by scanning electron microscopy. Therefore, our results demonstrate that bacterial aggregates called biofilms, that are resistant to treatment by antibiotics, can be detected by standard culture techniques, and may play a major etiologic role in posttympanostomy otorrhea.

Synthesis and antibacterial activity of 4,5,6,7-tetrahydro-thieno[3,2-c]pyridine quinolones

Synthesis and antibacterial activity of a number of substituted 4,5,6,7-tetrahydro-thieno[3,2-c]pyridine quinolones is reported. The antibacterial activities were evaluated in standard in vitro MIC assay method. Some of the compounds showed in vitro (MIC) antibacterial activity comparable to those of Gatifloxacin, Ciprofloxacin, and Sparfloxacin.

A comparative study of two antimicrobial/anti-inflammatory formulations in the treatment of canine otitis externa

The efficacy and tolerability of a marbofloxacin-clotrimazole-dexamethasone otic suspension (MCD) was compared with a standard topical treatment using a phase III clinical trial protocol. In a total of 140 dogs with clinical signs of acute or subacute otitis externa, Staphylococcus, Pseudomonas, Enterobacteriaceae and Malassezia were isolated from samples taken at inclusion to identify the causative pathogen; a further sample was collected in the event of failure or relapse, and from dogs (at day 14) for which Pseudomonas species had been isolated at inclusion. One group received MCD (10 drops per affected ear) once daily and a second received Surolan (containing polymyxin B, miconazole and prednisolone) (5 drops per affected ear), twice daily. Each group received treatment for 7 or 14 days according to the clinical outcome on day 7. Efficacy and tolerability were evaluated on days 7, 14 and, if necessary, 28 for dogs treated for 14 days. The trial demonstrated equivalence of both treatments in terms of efficacy, with a cure rate of 58.3% for MCD and 41.2% for Surolan. Both medications were equally well tolerated by dogs, but MCD was superior in terms of pain relief, decrease in pus quantity and smell, response rate and investigator's assessment on day 14.

Ototopical Ciprofloxacin in a Glycerin Vehicle for the Treatment of Acute External Otitis

We conducted a prospective, randomized, controlled, double-blind study of 33 patients to compare the efficacy and tolerability of a new glycerin formulation of ototopical 0.3% ciprofloxacin with that of a conventional aqueous formulation of ciprofloxacin for the treatment of acute external otitis. Outcomes measures were resolution of discharge, swelling, pain, and redness and the incidence of adverse side effects. Patients were examined on three occasions: on the day of enrollment (visit 1), 48 to 72 hours later (visit 2), and 7 days after enrollment (visit 3). At visit 2, the patients in the glycerin group showed a significantly greater resolution of discharge. We observed the same pattern with respect to swelling, pain, and redness, which resolved more quickly in the glycerin group, although not significantly so. All patients were cured by visit 3, and the two treatments were equally well tolerated. On the basis of our findings, we conclude that the glycerin formulation of ototopical 0.3% ciprofloxacin appears to be at least as effective as the aqueous form in the treatment of acute external otitis—and in the case of otorrhea, more so.