Risk assessment of the mechanical spread of bacterial pathogens due to Lasius neglectus ants infesting a tertiary hospital.

INTRODUCTION: Mechanical spread of microbial pathogens has been investigated in cockroaches, but less well in ants. Considerably less information is available for ants. An investigation into ant-borne mechanical pathogen transmission was triggered by an infestation of a tertiary care hospital with Lasius neglectus ants. METHODS: The L. neglectus infestation of the orthopaedic surgery department, the ear-nose-throat clinic and the eye clinic as well as of outdoor areas was monitored and correlated with seasonal and weather influences. Microbial colonization on the ants' exoskeleton as well as in homogenates of complete insects and decolonization dynamics of artificial Staphylococcus aureus colonization on the exoskeleton was assessed. RESULTS: In a low-level infestation setting, L. neglectus activity showed seasonal variations and was positively correlated with temperature (r = 0.7515; P=0.0368) but not with precipitation (r = 0.4699, P=0.2431). Colonization with environmental commensals dominated, while exoskeleton colonization with bacteria with potential aetiological relevance for nosocomial infections was higher for ants from the inpatient setting (6%) than from outdoor areas (0%). Artificial colonization of the exoskeleton with S. aureus vanished to values statistically indistinguishable from baseline within 72 h. CONCLUSIONS: Low colonization rates with aetiologically relevant bacteria and rapid spontaneous decolonization in the case of contamination make ant-borne transmissions to patients unlikely.

Introducing "Rapid phage susceptibility testing" (RPST): an accelerated lytic phage activity test for routine diagnostic laboratories within eight hours.

Phage therapy, particularly for infections due to multi-drug-resistant bacteria, is increasingly gaining in importance. Consecutively, there is a rising need for phage testing in routine diagnostic laboratories. The incubation time of phage susceptibility testing for detecting lytic phage activity on phage/host strain combinations was evaluated. A standardized approach for routine diagnostic laboratories provided reliably detectable lysis zones within 8 hours.

Influence of bed making on loads of airborne and surface-associated drug-resistant bacteria in patient rooms.

INTRODUCTION: Limited information is available on the kinetics of airborne multi-drug-resistant bacteria after making patients' beds. Previous experience of bed making on loads of meticillin-resistant Staphylococcus aureus (MRSA) was re-evaluated with a substantial sample size and, for the first time, simultaneous examination of the environmental load of multi-drug-resistant Gram-negative bacteria (MDRGN) was undertaken. METHODS: Airborne pathogen measurement was carried out in 26 rooms with patients with MRSA and 25 rooms with patients with MDRGN before (-1 min) and after (1 min, 15 min, 60 min) bed making at distances of 0 m and 3 m from the bed. Surface sampling was performed in the patients' surroundings. Factors of potential influence were recorded. RESULTS: Gram-positive non-pathogenic species dominated the air samples, while Gram-negative organisms constituted only 1.4%. Bed making shifted the proportions towards coagulase-negative staphylococci and S. aureus. A transient increase in MRSA in room air was detected in most samples 1 min and 15 min after bed making. MDRGN were detected in the air of two patient rooms. Surface samples showed that MRSA, but not MDRGN, was isolated regularly in the patient environment. Correlation between airborne and surface pathogen loads after bed making was demonstrated. CONCLUSIONS: The study results indicate the importance of wearing a face mask in combination with cautious handling techniques when making the beds of patients carrying multi-drug-resistant bacteria. If the carrier status of a patient is unknown, consideration should be given to protective measures for staff and other patients present during and shortly after bed making. Surface disinfection should not be started until at least 30 min after bed making.

Molecular epidemiology study of a nosocomial Moraxella catarrhalis outbreak in a neurological rehabilitation unit.

BACKGROUND: Moraxella catarrhalis is a common agent causing upper and lower respiratory tract infections, particularly of ventilated patients. The bacteria are transmitted between humans by direct and indirect contacts. However, reports of nosocomial outbreaks by this pathogen are scarce. AIM: To analyse M. catarrhalis strains isolated during an outbreak in a medical rehabilitation centre to reveal their clonal relationship and to elucidate potential transmission routes. METHODS: Extensive environmental and medical staff sampling was performed. Phenotypic and genotypic analyses of 15 isolates were executed, including repetitive element palindromic polymerase chain reaction (repPCR) and whole-genome sequencing. Furthermore, an intensified hygiene regimen was installed. FINDINGS: The clonal nature of nine patient isolates and a simultaneous presence of separate entities including a strain isolated from a physician during staff screening was confirmed. Although neither asymptomatic carriers among the staff persons nor outbreak strain-contaminated fomites were identified for a specific intervention, the outbreak ceased due to maximum general and specific hygiene precautions. Retrospective analysis showed the increasing prevalence of M. catarrhalis strains over a period of two years before the incidence. Since then and after returning to the regular hygiene regimen, only one patient with a phenotypically diverse M. catarrhalis isolate has been documented. CONCLUSION: The first M. catarrhalis outbreak involving nine patients of a neurological and trauma rehabilitation centre was reported. Potential transmission pathways were discussed. Comprehensive outbreak analyses insinuated the extension of routine laboratory storage time for defined species.

Comparing a single-day swabbing regimen with an established 3-day protocol for MRSA decolonization control.

OBJECTIVES: Success of methicillin-resistant Staphylococcus aureus (MRSA) decolonization procedures is usually verified by control swabs of the colonized body region. This prospective controlled study compared a single-day regimen with a well-established 3-day scheme for noninferiority and adherence to the testing scheme. METHODS: Two sampling schemes for screening MRSA patients of a single study cohort at a German tertiary-care hospital 2 days after decolonization were compared regarding their ability to identify MRSA colonization in throat or nose. In each patient, three nose and three throat swabs were taken at 3- to 4-hour intervals during screening day 1, and in the same patients once daily on days 1, 2 and 3. Swabs were analysed using chromogenic agar and broth enrichment. The study aimed to investigate whether the single-day swabbing scheme is not inferior to the 3-day scheme with a 15% noninferiority margin. RESULTS: One hundred sixty patients were included, comprising 105 and 101 patients with results on all three swabs for decolonization screening of the nose and throat, respectively. Noninferiority of the single-day swabbing scheme was confirmed for both pharyngeal and nasal swabs, with 91.8% and 89% agreement, respectively. The absolute difference of positivity rates between the swabbing regimens was 0.025 (-0.082, 0.131) for the nose and 0.006 (-0.102, 0.114) (95% confidence interval) for the pharynx as calculated with McNemar's test for matched or paired data. Compliance with the single-day scheme was better, with 12% lacking second-day swabs and 27% lacking third-day swabs from the nostrils. CONCLUSIONS: The better adherence to the single-day screening scheme with noninferiority suggests its implementation as the new gold standard.

Validated measurements of microbial loads on environmental surfaces in intensive care units before and after disinfecting cleaning.

AIMS: Preanalytic aspects can make results of hygiene studies difficult to compare. Efficacy of surface disinfection was assessed with an evaluated swabbing procedure. METHODS AND RESULTS: A validated microbial screening of surfaces was performed in the patients' environment and from hands of healthcare workers on two intensive care units (ICUs) prior to and after a standardized disinfection procedure. From a pure culture, the recovery rate of the swabs for Staphylococcus aureus was 35%-64% and dropped to 0%-22% from a mixed culture with 10-times more Staphylococcus epidermidis than S. aureus. Microbial surface loads 30 min before and after the cleaning procedures were indistinguishable. CONCLUSIONS: The quality-ensured screening procedure proved that adequate hygiene procedures are associated with a low overall colonization of surfaces and skin of healthcare workers. Unchanged microbial loads before and after surface disinfection demonstrated the low additional impact of this procedure in the endemic situation when the pathogen load prior to surface disinfection is already low. SIGNIFICANCE AND IMPACT OF THE STUDY: Based on a validated screening system ensuring the interpretability and reliability of the results, the study confirms the efficiency of combined hand and surface hygiene procedures to guarantee low rates of bacterial colonization.

Predictors of colonization with Staphylococcus species among patients scheduled for cardiac and orthopedic interventions at tertiary care hospitals in north-eastern Germany-a prevalence screening study.

As methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in humans are a global challenge. In Mecklenburg and Western Pomerania (Germany) 1,517 patients who underwent surgical interventions were systematically screened for MRSA and MSSA colonization on the day of hospital admission and discharge. Demographic data, risk factors and colonization status of the (i) nose, (ii) throat, (iii) groin, and (iv) thorax or site of surgical intervention were determined. Of the 1,433 patients who were included for further evaluation, 331 (23.1%) were colonized with MSSA, while only 17 (1.2%) were MRSA carriers on the day of hospital admission. A combination of nose, throat and groin swabs returned a detection rate of 98.3% for MSSA/MRSA. Trauma patients had lower prevalence of MRSA/MSSA (OR 0.524, 95% CI: 0.37-0.75; p < 0.001) than patients with intended orthopedic interventions. Males showed significantly higher nasal S. aureus carrier rates than females (odds ratio (OR) = 1.478; 95% CI: 1.14-1.92; p = 0.003). Nasal S. aureus colonization was less frequent among male smokers as compared to non-smokers (chi2 = 16.801; phi = 0.154; p < 0.001). Age, gender and smoking had a significant influence on S. aureus colonization. Combining at least three different swabbing sites should be considered for standard screening procedure to determine S. aureus colonization at patients scheduled for cardiac or orthopedic interventions at tertiary care hospitals.

Endocultivation: continuous application of rhBMP-2 via mini-osmotic pumps to induce bone formation at extraskeletal sites.

The continuous presence of recombinant human bone morphogenetic protein 2 (rhBMP-2) inside a scaffold may be crucial to the outcome in bone tissue engineering. This study investigated whether the release of the growth factor rhBMP-2 via different continuous application schemes influences histomorphological aspects of the hard and soft tissues induced. Three-dimensionally printed hydroxyapatite scaffolds were implanted into one latissimus dorsi muscle of 42 female Lewis rats. Simultaneously implanted mini-osmotic pumps were used to provide a continuous application of rhBMP-2 over 1, 2, or 4 weeks (total dose 200µg). A reference group received rhBMP-2 at the time of implantation only, and a control group received only block implantation. Bone density and histological examinations were performed after 8 weeks. No significant difference in bone density was found between the groups; however, the blood vessel count differed significantly between the groups receiving continuous treatments and both the control group and simultaneous rhBMP-2 treatment group (P<0.0001). Soft tissue types were distributed differently among the study groups. RhBMP-2 application via mini-osmotic pumps is as suitable for inducing bone formation as a single application at the time of implantation. The time interval over which rhBMP-2 was administered had no impact on the amount of new bone formation, probably due to the study duration and low local concentrations of growth factor.

Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery.

BACKGROUND AND PURPOSE: Radiographic assessment of cerebral metastasis after stereotactic radiosurgery remains a major challenge in neuro-oncology. It is often difficult to distinguish tumor progression from radiation necrosis in this setting using conventional MR imaging. The objective of this study was to compare the diagnostic sensitivity and specificity of different functional imaging modalities for detecting tumor recurrence after stereotactic radiosurgery. MATERIALS AND METHODS: We retrospectively reviewed patients treated between 2007 and 2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling, FDG-PET, and thallium SPECT before stereotactic biopsy. Diagnostic accuracy, specificity, sensitivity, positive predictive value, and negative predictive value were calculated for each imaging technique by using the pathologic diagnosis as the criterion standard. RESULTS: Six patients (42%) had tumor progression, while 8 (58%) developed radiation necrosis. FDG-PET and arterial spin-labeling were equally sensitive in detecting tumor progression (83%). However, the specificity of arterial spin-labeling was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of arterial spin-labeling. CONCLUSIONS: In our series, arterial spin-labeling positivity was closely associated with the pathologic diagnosis of tumor progression after stereotactic radiosurgery. Validation of this finding in a large series is warranted.

Antimicrobial effect of Australian antibacterial essential oils as alternative to common antiseptic solutions against clinically relevant oral pathogens.

BACKGROUND: The aim of the study was to examine the in vitro antibacterial activity of different oils in comparison to antiseptics against oral microorganisms. METHODS: The antimicrobial effect of tea tree oil (TTO), eucalyptus oil (EO), lemon grass oil (LGO), and a eucalyptus-based oil mixture (MXT) were tested in comparison to chlorhexidine digluconate (CHX), povidone-iodine (BTA), and octenidine dihydrochloride (OCT). Oral bacterial strains and candida species using the agar diffusion test were used for the antimicrobial study. RESULTS: All tested oils showed antimicrobial potency against the tested biological indicators. In comparison of all tested substances the largest effective zones were measured for LGO, followed from MXT and CHX. TTO and EO were less effective against the tested microorganisms followed from BTA. CONCLUSIONS: The results of this study show that some essential oils have better antimicrobial properties than standard oral antiseptics. In a follow-up step, the ideal concentrations, the composition of essential oils, and the mode of application will be evaluated. The antibacterial efficacy of essential oils might be promising for use in clinical and oral hygiene applications. The cost reduction and availability particularly in rural areas with easy access to the originating plants might be advantageous factors to be considered.

[Surveillance reports on pathogens and their antibiotic resistance patterns - a recommendation for standardization]. / Surveillanceberichte zu Erregern und Antibiotikaresistenzen - eine Empfehlung zur Standardisierung.

Surveillance reports on infectious agents and their antibiotic resistance patterns as well as on the usage of antibiotics are now enforced by law for many medical institutions in Germany. However, specific practice-oriented recommendations concerning the appropriate extent and informative mode of presentation are lacking. This consensus statement resulted from the experience from five German university hospitals in handling data from infection epidemiology and in the various possibilities for the presentation of surveillance reports. The consensus statement provides recommendations for the preparation of the legally demanded surveillance reports, extending the existing regulations. The relevance of statements on frequency and quality of microbiological tests is included. Furthermore, modes for the standardization of the data analysis are suggested in order to achieve a regional and national comparability of the results on a high quality level, similarly to the established standardized surveillance of nosocomial infections. This consensus statement describes the form in which the legally enforced reports can be presented in an informative and standardized way in order to facilitate the deduction and realization of preventive measurements.

Endocultivation: the influence of delayed vs. simultaneous application of BMP-2 onto individually formed hydroxyapatite matrices for heterotopic bone induction.

When bone morphogenetic protein (BMP) is delivered to matrices in vivo may affect tissue engineered bone constructs for jaw reconstruction after cancer surgery. This study compared the effects of BMP application at different times after matrix implantation for heterotopic bone induction in a rat model. Hydroxyapatite blocks were implanted unilaterally onto the surface of the latissimus dorsi muscle. A second block was implanted onto the contralateral muscle after 1, 2 or 4 weeks and 200 µg rhBMP-2 was injected into the blocks on both sides. Bone formation and density inside the blocks was analysed by CT and histology. 8 weeks after BMP application increases in bone density within the scaffolds were most pronounced in the simultaneous application group (179 HU). Less pronounced increases were observed for the 1 (65 HU), 2 (58 HU) and 4 (31 HU; p<0.0001) week delay group. Homogeneous bone induction started from the central channel of the blocks. Capillaries and larger vessels were seen in all constructs, samples receiving delayed BMP treatment demonstrated significantly greater neovascularization. Delayed application of BMP was less effective for heterotopic bone formation than simultaneous application. A central channel allows homogeneous bone induction directly from the centre of the blocks.

Influence of collagen and chondroitin sulfate (CS) coatings on poly-(lactide-co-glycolide) (PLGA) on MG 63 osteoblast-like cells.

Poly-(lactide-co-glycolide) (PLGA) is an FDA-approved biodegradable polymer which has been widely used as a scaffold for tissue engineering applications. Collagen has been used as a coating material for bone contact materials, but relatively little interest has focused on biomimetic coating of PLGA with extracellular matrix components such as collagen and the glycosaminoglycan chondroitin sulfate (CS). In this study, PLGA films were coated with collagen type I or collagen I with CS (collagen I/CS) to investigate the effect of CS on the behaviour of the osteoblastic cell line MG 63. Collagen I/CS coatings promoted a significant increase in cell number after 3 days (in comparison to PLGA) and after 7 days (in comparison to PLGA and collagen-coated PLGA). No influence of collagen I or collagen I/CS coatings on the spreading area after 1 day of culture was observed. However, the cells on collagen I/CS formed numerous filopodia and displayed well developed vinculin-containing focal adhesion plaques. Moreover, these cells contained a significantly higher concentration of osteocalcin, measured per mg of protein, than the cells on the pure collagen coating. Thus, it can be concluded that collagen I/CS coatings promote MG 63 cell proliferation, improve cell adhesion and enhance osteogenic cell differentiation.

Future of local bone regeneration - Protein versus gene therapy.

The most promising attempts to achieve bone regeneration artificially are based on the application of mediators such as bone morphogenetic proteins (BMPs) directly to the deficient tissue site. BMPs, as promoters of the regenerative process, have the ability to induce de novo bone formation in various tissues, and many animal models have demonstrated their high potential for ectopic and orthotopic bone formation. However, the biological activity of the soluble factors that promote bone formation in vivo is limited by diffusion and degradation, leading to a short half-life. Local delivery remains a problem in clinical applications. Several materials, including hydroxyapatite, tricalcium phosphate, demineralised bone matrices, poly-lactic acid homo- and heterodimers, and collagen have been tested as carriers and delivery systems for these factors in a sustained and appropriate manner. Unfortunately these delivery vehicles often have limitations in terms of biodegradability, inflammatory and immunological rejection, disease transmission, and most importantly, an inability to provide a sustained, continuous release of these factors at the region of interest. In coping with these problems, new approaches have been established: genes encoding these growth factor proteins can be delivered to the target cells. In this way the transfected cells serve as local "bioreactors", as they express the exogenous genes and secrete the synthesised proteins into their vicinity. The purpose of this review is to present the different methods of gene versus growth factor delivery in tissue engineering. Our review focuses on these promising and innovative methods that are defined as regional gene therapy and provide an alternative to the direct application of growth factors. Various advantages and disadvantages of non-viral and viral vectors are discussed. This review identifies potential candidate genes and target cells, and in vivo as well as ex vivo approaches for cell transduction and transfection. In explaining the biological basis, this paper also refers to current experimental and clinical applications.

Life-threatening bite injury of the lower lip after use of metamizole.

INTRODUCTION: Bite wounds of the oral mucosa heal after eliminating the causative irritant, but there are serious exceptions from the rule. We present the case of a 37-year-old woman with an ulcer of the mucosa of the lower lip, which had been present for 10 days, and leucopenia. DISCUSSION: Agranulocytosis after the use of metamizole is part from leukaemia and lues, a rare reason for non-healing ulcers of the mucosa of the oral cavity without fulminant signs for inflammation. CONCLUSION: As this is a life-threatening disease, medical therapy must begin immediately.

A new method of monitoring osteomyelitis.

Chronic infections of bone such as osteomyelitis are frequent events, especially in immunocompromised or diabetic patients, and costly on a national level. Incorrect treatment or delayed diagnosis may lead to loss of the affected extremity or mandible. The aim of this study was to assess the possible value of urinary lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) concentrations in the monitoring of mandibular osteomyelitis. Patients were assigned to the following groups: group 1 (n=85), control; group 2a (n=38), patients with active disease; group 2b (n=25), patients of group 2a 6 months after successful treatment; group 2c (n=7), patients of group 2a with ongoing osteomyelitis 6 months after treatment. The range and upper limit of normal values (HP(max) and LP(max)) were determined in group 1. Levels of LP and HP were measured by high-performance liquid chromatography and fluorescence detection. There was a significant decrease (mean 45.43% for HP and 32.12% for LP) in samples of group 2b compared to 2a (P<0.001 for HP and LP). There was a significant increase in HP values in samples from group 2c compared to 2a (P=0.018). The urinary concentrations of HP and LP appear to act as a marker of disease activity, with a decrease reflecting treatment success and an increase or stable values indicating persistent disease. An inexpensive tool (US$5 per analysis) for the monitoring of osteomyelitis is described.

Learning by doing virtually.

Selective reduction of bone without collateral damage (nerves, teeth) is essential in apicectomy. To test whether skills acquired on a virtual apicectomy simulator (VOXEL-MAN system with integrated force-feedback) are transferable from virtual to physical reality, two groups of trainees were compared. Group 1 received computer-based virtual surgical training before performing an apicectomy in a pig cadaver model. The probability of preserving vital neighboring structures was improved significantly, i.e. six-fold, after virtual surgical training (P<0.001). The average volume of the bony defects created by the trainees of Group 2 (mean: 0.47 ml) was significantly (P<0.001) larger than by the trainees of Group 1 (mean: 0.25 ml). Most importantly, the ability to objectively self-assess performance was significantly improved after virtual training. Training with a virtual apicectomy simulator appears to be effective, and the skills acquired are transferable to physical reality.

Expression of cellular adhesion molecule 'OPCML' is down-regulated in gliomas and other brain tumours.

The four GPI-anchored cell adhesion molecules that exemplify the IgLON family are most highly expressed in the nervous system and associate to form up to six different heterodimeric 'Diglons' that can modify cell adhesion and inhibit axon migration. Recently, two members, OPCML and LSAMP, were identified as putative tumour suppressor genes in ovarian and renal carcinomas respectively. In this study, we investigated OPCML expression in nonneoplastic brain tissue and 35 brain tumours (18 glioblastoma multiformes, five anaplastic gliomas, five meningiomas, six metastases and one medulloblastoma) and four glioma cell lines using quantitative reverse transcriptase polymerase chain reaction (RT-PCR). OPCML was highly expressed in cerebellum, less so in cerebral cortex, frontal lobe and meninges and was significantly reduced or absent in 83% of brain tumours and all cell lines compared with nonneoplastic whole brain. Two OPCML splice variants have been identified in humans, termed alpha1 and alpha2, but the latter has not been demonstrated in human neural tissues. Using PCR with specific primers, nonneoplastic brain and 3/6 of tested brain tumours expressed both splice variants, whereas the remaining brain tumours only expressed the alpha2 variant. Hypermethylation of the alpha1 OPCML promoter, associated with down-regulation of expression in ovarian tumours, did not correlate with expression levels in the subset of brain tumours tested, implying transcription of OPCML from an alternative promoter or a different mechanism of down-regulation. This study demonstrates that OPCML down-regulation occurs in the majority of brain tumours tested, warranting further investigation of OPCML and other IgLONs in the development and progression of brain tumours.