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.

BACKGROUND: Due to considerable differences in pathogenicity, Haemophilus influenzae, H. parainfluenzae and H. haemolyticus have to be reliably discriminated in routine diagnostics. Retrospective analyses suggest frequent misidentifications of commensal H. haemolyticus as H. influenzae. In a multi-center approach, we assessed the suitability of fluorescence in situ hybridization (FISH) and matrix-assisted laser-desorption-ionization time-of-flight mass-spectrometry (MALDI-TOF-MS) for the identification of H. influenzae, H. parainfluenzae and H. haemolyticus to species level. METHODOLOGY: A strain collection of 84 Haemophilus spp. comprising 50 H. influenzae, 25 H. parainfluenzae, 7 H. haemolyticus, and 2 H. parahaemolyticus including 77 clinical isolates was analyzed by FISH with newly designed DNA probes, and two different MALDI-TOF-MS systems (Bruker, Shimadzu) with and without prior formic acid extraction. PRINCIPAL FINDINGS: Among the 84 Haemophilus strains analyzed, FISH led to 71 correct results (85%), 13 uninterpretable results (15%), and no misidentifications. Shimadzu MALDI-TOF-MS resulted in 59 correct identifications (70%), 19 uninterpretable results (23%), and 6 misidentifications (7%), using colony material applied directly. Bruker MALDI-TOF-MS with prior formic acid extraction led to 74 correct results (88%), 4 uninterpretable results (5%) and 6 misidentifications (7%). The Bruker MALDI-TOF-MS misidentifications could be resolved by the addition of a suitable H. haemolyticus reference spectrum to the system's database. In conclusion, no analyzed diagnostic procedure was free of errors. Diagnostic results have to be interpreted carefully and alternative tests should be applied in case of ambiguous test results on isolates from seriously ill patients.

Poly(3-hydroxybutyrate) (PHB) patches for covering anterior skull base defects - an animal study with minipigs.

CONCLUSION: We conclude that PHB patch material may fulfil the specific requirements that are necessary for a dural substitute, including defect closure, stability and biocompatibility. Our results support the assumed positive influence of PHB on bone regeneration. OBJECTIVES: Although many experimental and clinical studies have been performed to identify a suitable material to repair defects of the dura mater, no ideal dural substitute is currently available. PHB is a biodegradable and biocompatible polymer that might serve as dural substitute and osteosynthesis material in cranial bone defects. MATERIALS AND METHODS: Different standardized PHB patches were used in six minipigs for covering defined bone defects in the anterior skull base including a dura mater lesion as well as in the frontal sinus front wall. After a defined time of implantation of 3, 6, and 9 months PHB patches were explanted and examined for clinical findings, biodegradation, presence of microorganisms, histological findings, and electron microscopy. RESULTS: The examinations revealed an increasing closure of bone defect corresponding with time. The anterior skull base bone defect was completely closed after 9 months. The histological findings revealed a connective tissue and callus formation around the PHB patches with fibroblasts and foreign body/giant cell reaction growing through PHB membrane pores. There were no reactions or adhesions between brain and PHB or dura mater and PHB, respectively. Investigations of biodegradation and electron microscopy revealed a continuous breakdown of PHB in the course of time with variations due to different PHB structures. Microbiological investigations could not detect any florid intracranial infection.

Prospective controlled study of microbial colonization of the trachea in tracheotomized and laryngectomized patients with HME (heat and moisture exchanger).

CONCLUSION: The use of heat and moisture exchangers (HMEs) does not endanger tracheostomy patients in terms of additional exposure to pathogenic microorganisms. OBJECTIVE: Stoma filters in the form of HMEs cause a beneficial convection of respiratory air in tracheotomized and laryngectomized patients. We investigated whether or not this may lead to an altered microbial ecology in the non-physiologically colonized lower respiratory tract. MATERIALS AND METHODS: To test this hypothesis, material from the trachea of stoma patients was prospectively collected utilizing a standardized swab technique and subsequent aerobic quantitative culture assays of the suspended and serially diluted material. With this approach, we examined the microbial flora in 6 and 5 patients after laryngectomy/tracheostomy, respectively, without any protection, in 11 patients after laryngectomy with a bib, and in 8 laryngectomized patients with an HME. RESULTS: In all three groups, Staphylococcus aureus and Candida albicans were most frequently demonstrated. The microbial count of facultative pathogenic agents ranged between 3×10(2) colony forming units (cfu)/ml and 10(6) cfu/ml and was similar in the three groups. With respect to the absence of inflammatory symptoms in every patient, all isolates could be regarded as colonizers. Among the antibiotics tested with each isolate, cefuroxime proved to be the most effective against the facultative pathogenic bacteria.

Predictors of pneumonia in acute stroke patients admitted to a neurological intensive care unit.

OBJECTIVE: To determine independent clinical predictors of stroke-associated pneumonia (SAP) that are available in all patients on day of hospital admission. METHODS: We studied 236 patients with acute ischemic stroke admitted to the neurological intensive care unit at our university hospital. Risk factors of SAP and of non-responsivity of early-onset pneumonia (EOP; onset within 72 hours after admission) to initial antibacterial treatment were analyzed. RESULTS: Incidence of SAP was 22%. The following independent risk factors were found to predict SAP with 76% (EOP: 90%) sensitivity and 88% specificity: dysphagia (RR, 9.92; 95% CI, 5.28-18.7), National Institute of Health Stroke Scale > or = 10 (RR, 6.57; CI, 3.36-12.9), non-lacunar basal-ganglia infarction (RR, 3.10; CI, 1.17-5.62), and any other infection present on admission (RR, 3.78; CI, 2.45-5.83). Excluding the patients with other infections on admission, the same independent risk factors (except infection) were found. Further, but not independent risk factors were: combined brainstem and cerebellar infarction, infarction affecting more than 66% of middle cerebral artery territory, hemispheric infarction exceeding middle cerebral artery territory, impaired vigilance, mechanical ventilation, age > or = 73 years, current malignoma, and cardioembolic stroke, whereas patients with lacunar infarctions had significantly lower risk. In contrast to previous reports, no impact of male gender or diabetes was found. Initial vomiting, especially if associated with impaired vigilance, predicted antibacterial treatment non-responsivity of EOP. In nonresponders exclusively fungal pathogens were identified. CONCLUSION: Increased risk of pneumonia in acute stroke patients can be sufficiently predicted by a small set of clinical risk factors.