Effects of High Hydrostatic Pressure on Bacterial Growth on Human Ossicles Explanted from Cholesteatoma Patients

Abstract

BackgroundHigh hydrostatic pressure (HHP) treatment can eliminate cholesteatoma cells from explanted human ossicles prior to re-insertion. We analyzed the effects of HHP treatment on the microbial flora on ossicles and on the planktonic and biofilm states of selected isolates.MethodologyTwenty-six ossicles were explanted from cholesteatoma patients. Five ossicles were directly analyzed for microbial growth without further treatment. Fifteen ossicles were cut into two pieces. One piece was exposed to HHP of 350 MPa for 10 minutes. Both the treated and untreated (control) pieces were then assessed semi-quantitatively. Three ossicles were cut into two pieces and exposed to identical pressure conditions with or without the addition of one of two different combinations of antibiotics to the medium.Differential effects of 10-minute in vitro exposure of planktonic and biofilm bacteria to pressures of 100 MPa, 250 MPa, 400 MPa and 540 MPa in isotonic and hypotonic media were analyzed using two patient isolates of Staphylococcus epidermidis and Neisseria subflava. Bacterial cell inactivation and biofilm destruction were assessed by colony counting and electron microscopy.Principal FindingsA variety of microorganisms were isolated from the ossicles. Irrespective of the medium, HHP treatment at 350 MPa for 10 minutes led to satisfying but incomplete inactivation especially of Gram-negative bacteria. The addition of antibiotics increased the efficacy of elimination. A comparison of HHP treatment of planktonic and biofilm cells showed that the effects of HPP were reduced by about one decadic logarithmic unit when HPP was applied to biofilms.High hydrostatic pressure conditions that are suitable to inactivate cholesteatoma cells fail to completely sterilize ossicles even if antibiotics are added. As a result of the reduced microbial load and the viability loss of surviving bacteria, however, there is a lower risk of re-infection after re-insertion.

Rapid Discrimination of Haemophilus influenzae, H. parainfluenzae, and H. haemolyticus by Fluorescence In Situ Hybridization (FISH) and Two Matrix-Assisted Laser-Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) Platforms

“…were isolated from 26 sputa, 9 nasal swabs, 9 tracheal secretions, 7 broncho-alveolar lavages, 7 pharyngeal swabs (3 of them from known mucoviscidosis patients), 6 eye swabs, 5 nasal secretions, 2 bronchial secretions, 2 ear swabs, 1 palatine swab, 1 ossicle fragment, 1 maxillary sinus swab, and 1 peritonsillar abscess (Table 1) in routine microbiological diagnostic analyses. One isolate, a H. parainfluenzae strain, was isolated in the course of a recent anonymized study [28] at the University of Rostock. Patient-related data associated with the bacterial isolates, i.e., age and sex of the patients, are not presented for ethical considerations.…”

Difficulties in species identification within the genusHaemophilus— A pilot study addressing a significant problem for routine diagnostics

“…The remaining single isolate, a H. parainfl uenzae isolate, was collected at the University of Rostock from an anonymous patient who visited the University of Rostock hospital complaining of an URT infection in the course of the study [36]. The 76 patients comprised 49 men and 27 women.…”

Repair of cartilage defects with devitalized osteochondral tissue: A pilot animal study

“…Our previous study showed that HHP‐devitalized cartilage has still strong chondroinductive potential . Devitalization using HHP represents a gentle technique for cell inactivation while extracellular cartilage matrix is preserved . Therefore, devitalized cartilage may be an ideal scaffold for the repair of cartilage lesions.…”

“…17 Devitalization using HHP represents a gentle technique for cell inactivation while extracellular cartilage matrix is preserved. [29][30][31] Therefore, devitalized cartilage may be an ideal scaffold for the repair of cartilage lesions. In this pilot study, we investigated the feasibility of HHP-devitalized osteochondral plugs to repair osteochondral defects in a rabbit model over 12 weeks postoperatively.…”