Abstract Background Chlorhexidine (CHX) can lower the bacterial contamination on masks. This study explores how effectively CHX reduces the bacterial spectrum in the patient’s oral cavity and subsequently how this influences the contamination of masks. Methods Two intraoral samples were collected prior to any aerosol-generating treatment: the first before a 60-s CHX rinse and the second 10 min after. After dental treatment, the practitioner’s mask was imprinted onto agar plates. After cultivation, a Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-ToF) was used to identify the colony forming units. The identified species of the intraoral samples and mask imprints were then analysed based upon matches in bacterial species and quantity. Results A total of 108 unique patients were included, each receiving one aerosol-producing treatment. The total number of detected bacterial species in the oral cavity before the CHX rinse was 628, after 490. Staphylococcus aureus was found twice as often before the CHX rinse. The average amount of colony forming units on the mask’s imprints after the CHX rinse was 15.2. The bacterial species occurred in very similar proportions, with Staphylococcus species making up more than 50%. No species match between the oral samples and mask samples after the CHX rinse occurred most frequently (68.5%), followed by one match (25.9), two matches (3.7%) and three matches (1.9%). Conclusions A preprocedural CHX rinse reduces bacterial contamination on masks but has little effect on the spectrum of transmitted microorganisms. Our results suggest that the bacterial spectrum on the mask was not significantly influenced by the preprocedural change in the oral microbiota. Therefore, while CHX enhances clinical hygiene, it does not eliminate the risk of pathogenic transmission.

Given the global threat of increasing antibiotic resistance, risk factor detection of multi-resistant pathogens is particularly important. This is complicated by different definitions, using the international extended spectrum beta-lactamases (ESBL) definition and the German definition of multidrug-resistant Gram-negative pathogens (MRGN). Although the MRGN definition was primarily introduced for hospital hygiene measures, it is often used in outpatient or semi-inpatient areas. Due to the increasing numbers of outpatient treatments of the healthcare system, corresponding data is necessary for specific hygiene regulations. This study provides MRGN and ESBL data based on a stool examination and a questionnaire evaluation in the period 07/2021-03/2022 of 231 outpatients of Saarland University Medical Center before traveling abroad. There was a 3MRGN prevalence of 2.6% with five Escherichia coli and one Klebsiella pneumoniae and an ESBL prevalence of 5.6% with 13 ESBL Escherichia coli, four of which could also be classified as 3MRGN. These prevalences were compared with MRGN/ESBL prevalences in PubMed and Google Scholar in different areas of the German healthcare system in the period 2013-2024 at the federal state level. The selective literature search revealed geographical differences and missing prevalence data depending on the healthcare sector (outpatient/inpatient) and federal state. Resistance data is often evaluated according to international standards, i.e. according to the ESBL definition. Outpatient MRGN prevalences are hardly known despite the increasing numbers of outpatients of the healthcare system. Due to the scarcity of outpatient data, our study from a travel medicine clinic provides interesting epidemiological data that should be considered in the context of the COVID-19 pandemic.

To investigate the microbiological etiology of endogenous and exogenous postprocedural infectious endophthalmitis in patients referred to two tertiary eye care centers in the German federal state of Saarland over a five-year period (2019–2023). We retrospectively analyzed all cases of endophthalmitis treated at two ophthalmological centers in southwest Germany between January 1, 2019, and December 31, 2023. Included were only those cases for which vitreous aspirate specimens were subjected to microbiological analysis. Cases of exogenous endophthalmitis secondary to other ocular or periocular infections (e.g., microbial keratitis) or trauma were excluded. Microbiological pathogen identification was performed using Gram stain microscopy, conventional bacterial and fungal cultures, as well as broad-range bacterial and fungal polymerase chain reaction (PCR), followed by sequencing in PCR-positive samples. A total of 126 endophthalmitis vitreous aspirate samples from 126 patients with a mean age of 73.3 ± 11.4 years were included. The majority of endophthalmitis cases occurred after intravitreal injection (55.6

Abstract Background Dental unit waterlines (DUWLs) often provide optimal conditions for pathogens, including non-tuberculous mycobacteria, causing various infections in patients and practitioners. Preventive measures for non-tuberculous mycobacteria (NTM) remain unclear. Dental simulation units, which are used for student training, are very similar to classic dental units. While the water quality of dental units has been the subject of numerous studies, dental simulation units have received little attention to date. In particular, there are very few studies on the role of NTM in dental simulation units and on influencing factors such as water stagnation, structural conditions, and the effectiveness of a disinfection program. Methods In this study, 24 dental simulation units from two rooms in two different buildings of the Department for Operative Dentistry, Periodontology and Preventive Dentistry were examined for NTM. Water samples were analyzed from all simulation units, and biofilm swabs were additionally examined from room 2. All samples were incubated on solid and liquid culture media for 8 weeks. The species of NTM were identified using GenoType line probe assays. Results NTM were detected in 43 of 44 samples. Three different species were identified: M. gordonae was the most common, with 24 detections, followed by M. chelonae with 17 detections and M. chimaera with 3 detections. Conclusion The high contamination rate of dental simulation units highlights the need for further research to ensure a safe environment. No significant differences in terms of structural conditions could be found, while the influence of water stagnation and disinfection protocols warrants further investigation.

BACKGROUND:International travellers have the potential to transmit multidrug-resistant bacteria. However, the role of hygiene measures during travel has yet to be investigated. METHOD:Travellers were asked about their use of disinfectants and hygiene behaviour. Stool samples were analysed for Gram-negative multi-resistant bacteria (MDRO). These data were analysed, and a new MDRO risk map was developed and compared with data from existing literature. RESULT:Of 214 travellers, 6 (2.8 %) tested positive for an MDRO before and 16 (7.5 %) after the trip, with travel in known high-risk MDRO areas. Most travellers, 174 (81.3 %), regularly used disinfectants; only 36 (16.8 %) did not. There was no statistically significant correlation between the use of a disinfectant and colonisation with MDRO. In our and comparable studies, a high-risk region on the risk map was associated with an increased number of MDRO or extended-spectrum beta-lactamase (ESBL) positive returns. CONCLUSION:Travellers showed a high willingness to use disinfectants. This preliminary study highlights the need for larger, randomized studies to better assess the true impact of hand disinfectants on MDRO acquisition.

Introduction and aim Bioaerosols contaminate the personal protective equipment (PPE), especially masks. The PPE harbors microorganisms from various sources. However, no previous studies have investigated the specific sources of bacteria found on used masks and their correlation with those from the treated patient. Setting, design, material and methods Intraoral samples from the patient were collected prior to dental aerosol-producing treatments using a nylon flock fiber swab. After treatment, the practitioner’s mask was imprinted onto agar plates. Main outcome methods Following cultivation, colony forming units were counted and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). After the samples were analyzed, the intraoral samples as well as the mask samples were assessed for the presence of identical species, which were subsequently quantified. Results 126 treatments were included. One species match occurred most frequently (26.2%), followed by two (11.9%%) and three or more (3.97%). In the intraoral samples, Neisseria subflava occurred most often, within mask samples Staphylococcus epidermidis were detected most. Staphylococcus aureus could be cultivated three times more often in intraoral samples than on the mask. Discussion and conclusion Oral microorganisms originating from the patient’s oral cavity can be found on the outside of masks. When using PPE during treatments, it should therefore always be in mind that potentially pathogenic microorganisms may land on the mask becoming a source of for itself.

During the COVID-19 pandemic, dental face shields were recommended to protect the eyes. This study aimed to examine to what extent face shield and mask contamination differ when a pre-procedural mouth rinsing with Chlorhexidine (CHX) is conducted before treatment. In this prospective, randomized study, three groups of subjects were formed (rinsing with 0.1% CHX, water, or no rinsing (control) before aerosol-producing treatments). After each of the 301 treatments, the practitioner's face shield was swabbed with eSwab and the mask was brought into contact with agar plates. Sampling was done from the exterior surface only. Samples were cultured for 48 h at 35 degree celsius under aerobic and anaerobic conditions. Bacteria were classified by phenotypic characteristics, biochemical test methods, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Colony-forming units were counted and mean values were compared (WSR, H-test, U-test, p < 0.05). Within each subject group, face shields showed significantly more contamination than surgical masks (control group: 350 CFU, 50 CFU; intervention water: 270 CFU, 40 CFU; intervention CHX: 250 CFU, 30 CFU). Comparison of face shields of the different subject groups did not reveal any statistically significant differences. However, CHX resulted in a statistically significant bacterial reduction on surgical masks compared to the water and control group (control: 50 CFU, intervention water: 40 CFU, intervention CHX: 30 CFU). Contamination of face shields and surgical masks was highest in the control group, followed by the water group, and lowest in the intervention group with CHX. Streptococcus spp. and Staphylococcus spp. dominated, representing the oral and cutaneous flora. Contamination of masks worn with or without face shields did not differ. Presumably, face shields intercept first splashes and droplets, while the masks were mainly exposed to bioaerosol mist. Consequently, face shields protect the facial region and surroundings from splashes and droplets, but not the mask itself. A pre-procedural mouth rinse with CHX had no statistically significant reducing effect on contamination of the face shield, but a statistically significant reducing effect was observed on contamination of the mask.

BackgroundEnterobacter cloacae complex (ECCO) comprises closely related Enterobacteriaceae, causing a variety of infections ranging from mild urinary tract infections to severe bloodstream infections. ECCO has emerged as a significant cause of healthcare-associated infections, particularly in neonatal and adult intensive care.AimThe Enterobacter Cloacae COMplex PASsive Surveillance (EC-COMPASS) aims to provide a detailed multicentre overview of ECCO epidemiology and resistance patterns detected in routine microbiological diagnostics in four German tertiary care hospitals.Methods: In a sentinel cluster of four German tertiary care hospitals, all culture-positive ECCO results between January 01, 2020, and December 31, 2022, were analysed based on Hybase® laboratory data.FindingsAnalysis of 31,193 ECCO datasets from 14,311 patients revealed a higher incidence in male patients (p<0.05), although no significant differences were observed in ECCO infection phenotypes. The most common sources of ECCO were swabs (42.7%), urine (17.5%), respiratory secretions (16.1%), blood cultures (8.9%), and tissue samples (5.6%). The annual bacteraemia rate remained steady at approximately 33 cases per hospital. Invasive ECCO infections were predominantly found in oncology and intensive care units. Incidences of nosocomial outbreaks were infrequent and limited in scope. Notably, resistance to carbapenems was consistently low.Conclusion: EC-COMPASS offers a profound clinical perspective on ECCO infections in German tertiary healthcare settings, highlighting elderly men in oncology and intensive care units as especially vulnerable to ECCO infections. Early detection strategies targeting at-risk patients could improve ECCO infection management.

Purpose Blood culture (BC) diagnostics are influenced by many factors. We performed a targeted interdisciplinary analysis to analyse effects of various measures on BC diagnostics performance. Methods A diagnostic stewardship initiative was conducted at two intervention and two control wards in a German tertiary level hospital. The initiative comprised staff training on the correct indications and sampling for BC, implementation of information cards, labels to identify the collection site, regular BC bottle feedback including the number of bottles, filling volumes and identified pathogens; and the use of a specific sampling device (BD Vacutainer ® ). Before and after the interventions, two three-month measurement periods were performed, as well as a one-month follow-up period to assess the sustainability of the conducted measures. Results In total, 9362 BC bottles from 787 patients were included in the analysis. The number of BCs obtained from peripheral venous puncture could be increased at both intervention wards (44.0 vs . 22.2%, 58.3 vs . 34.4%), while arterial sampling could be reduced (30.6 vs . 4.9%). A total of 134 staff members were fully trained. The intervention led to a considerable increase in BC knowledge (from 62.4 to 79.8% correct answers) with differences between the individual professional groups. Relevant reduced contamination rates could be detected at both intervention wards. Conclusions As knowledge on the correct BC sampling and strategies to reduce contamination varies considerably between clinical departments and healthcare professionals, a targeted training should be adapted to the specific needs of the individual professional groups. An additional filling device is not necessary.

BACKGROUND:The thesis on which this paper is based intended to investigate whether the result of the microbiological vaginal swab has an influence on the outcome of the fertility treatment.METHODS:The microbiological vaginal swabs of patients who received fertility treatment at Saarland University Hospital were evaluated. Depending on the microorganisms detected, the swab result was classified as inconspicuous, intermediate, or conspicuous. The SPSS software was used to determine the correlation between the swab result and the outcome of the fertility treatment.RESULTS:Dysbiosis was associated with a worse outcome of fertility treatment. The pregnancy rate with a conspicuous swab was 8.6%, whereas it was 13.4% with an inconspicuous swab. However, this association was not statistically significant. Furthermore, an association of endometriosis with dysbiosis was found. Endometriosis was more frequent with a conspicuous swab result than with an inconspicuous result (21.1% vs. 17.7%), yet the correlation was not statistically significant. However, the absence of lactobacilli was significantly associated with endometriosis (p = 0.021). The association between endometriosis and a lower pregnancy rate was also statistically significant (p = 0.006).CONCLUSION:The microbiological vaginal and cervical swabs can be used as predictors for the success of fertility treatments. Further studies are needed to assess the impact of transforming a dysbiotic flora into a eubiotic environment on the success of fertility treatments.

BackgroundBacterial contamination on surgical masks puts a threat to medical staff and patients. The aim of the study was to investigate its contamination during dental treatments, wearing a face shield and performing a pre-procedural mouth rinsing with chlorhexidine (CHX).MethodsIn this prospective, randomized study, 306 treatments were included, 141 single-tooth (restorations) and 165 total dentition treatments (preventive or periodontal supportive ultrasonic application). A total of three groups (each: n = 102) were formed: participants rinsed for 60 s with 0.1 % CHX or with water before treatment, and, for control, a non-rinsing group was included. In view of the COVID-19 pandemic, a face shield covering the surgical mask enhanced personal protective equipment. After treatment, masks were imprinted on agar plates and incubated at 35°C for 48 h. Bacteria were classified by phenotypic characteristics, biochemical assay methods, and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Colonies (CFU) were counted and mean values were compared (Kruskal–Wallis-, U test, p < 0.05).ResultsChlorhexidine led to a statistically significant reduction of bacterial contamination of the surgical mask (mean: 24 CFU) in comparison with water (mean: 47 CFU) and non-rinsing (mean: 80 CFU). Furthermore, rinsing with water reduced CFU significantly in comparison with the non-rinsing group. There were no significant differences between single or total dentition treatments. Streptococcus spp., Staphylococcus spp., Micrococcus spp., and Bacillus spp. dominated, representing the oral and cutaneous flora.ConclusionA pre-procedural mouth rinse is useful to reduce the bacterial load of the surgical mask. However, contamination cannot be prevented completely, even by applying a face shield. In particular, during pandemic, it is important to consider that these additional protective measures are not able to completely avoid the transmission of pathogens bearing aerosols to the facial region. If antiseptic rinsing solutions are not available, rinsing with water is also useful.

Multidrug resistance is an emerging healthcare issue, especially concerning Pseudomonas aeruginosa. In this multicenter study, P. aeruginosa isolates with resistance against meropenem detected by routine methods were collected and tested for carbapenemase production and susceptibility against ceftazidime-avibactam. Meropenem-resistant isolates of P. aeruginosa from various clinical materials were collected at 11 tertiary care hospitals in Germany from 2017–2019. Minimum inhibitory concentrations (MICs) were determined via microdilution plates (MICRONAUT-S) of ceftazidime-avibactam and meropenem at each center. Detection of the presence of carbapenemases was performed by PCR or immunochromatography. For meropenem-resistant isolates (n = 448), the MIC range of ceftazidime-avibactam was 0.25–128 mg/L, MIC90 was 128 mg/L and MIC50 was 16 mg/L. According to EUCAST clinical breakpoints, 213 of all meropenem-resistant P. aeruginosa isolates were categorized as susceptible (47.5%) to ceftazidime-avibactam. Metallo-β-lactamases (MBL) could be detected in 122 isolates (27.3%). The MIC range of ceftazidime-avibactam in MBL-positive isolates was 4–128 mg/L, MIC90 was >128 mg/L and MIC50 was 32 mg/L. There was strong variation in the prevalence of MBL-positive isolates among centers. Our in vitro results support ceftazidime-avibactam as a treatment option against infections caused by meropenem-resistant, MBL-negative P. aeruginosa.

This study explores challenges and opportunities arising from pre-travel severe acute respiratory syndrome coronavirus 2 diagnostics for the conduct of travel medicine clinics. We found that such testing might offer huge opportunities to reach individuals who would otherwise not present to travel medicine clinics, such as individuals visiting friends and relatives in malaria-endemic countries.

Clostridioides difficile is a Gram positive spore-forming rod and mainly responsible for nosocomial diarrhea in developed nations. Molecular and antimicrobial surveillance is important for monitoring the strain composition including genotypes of high epidemiological importance such as ribotype 027 (RT027) and corresponding resistance patterns. 1535 isolates obtained from samples sent between 2014 and 2019 to the German National Reference Center (NRC) for diagnostic reasons (NRC strain set), and 1143 isolates from a Tertiary Care University Center in Saarland, Germany (non-NRC strain set), were evaluated using antibiotic susceptibility testing and ribotyping. In the NRC strain set, RT027 overtook RT001, the main RT found in the preceding studies, and dominated with 36.2%, followed by RT001 (13.3%), and RT014 (8.5%). Of note, since 2016 a constant decrease of RT027 could be noticed. In the non-NRC strain set a large strain diversity was present with RT014 (18%) and RT001 (8.9%) being most prevalent. In NRC samples, resistance towards metronidazole, vancomycin, moxifloxacin, clarithromycin and rifampicin was 2.7%, 0%, 57.1%, 53.2% and 19.2%, respectively. Metronidazole resistance was almost exclusively found in RT027 isolates. Rifampicin resistance was also observed predominantly in isolates of RT027, constituting an almost four-fold increase, when compared to preceeding studies in this region. In conclusion these data demonstrate that RT027 is a driver for rifampicin and metronidazole resistance, underlining the importance of continuous surveillance efforts.

Background: Liberal PCR testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is key to contain the coronavirus disease 2019 (COVID-19) pandemic. Combined multi-sample testing in pools instead of single tests might enhance laboratory capacity and reduce costs, especially in low- and middle-income countries. Objective: The purpose of our study was to assess the value of a simple questionnaire to guide and further improve pooling strategies for SARS-CoV-2 laboratory testing. Methods: Pharyngeal swabs for SARS-CoV-2 testing were obtained from healthcare and police staff, hospital inpatients, and nursing home residents in the southwestern part of Germany. We designed a simple questionnaire, which included questions pertaining to a suggestive clinical symptomatology, recent travel history, and contact with confirmed cases to stratify an individual’s pre-test probability of having contracted COVID-19. The questionnaire was adapted repeatedly in face of the unfolding pandemic in response to the evolving epidemiology and observed clinical symptomatology. Based on the response patterns, samples were either tested individually or in multi-sample pools. We compared the pool positivity rate and the number of total PCR tests required to obtain individual results between this questionnaire-based pooling strategy and randomly assembled pools. Findings: Between March 11 and July 5, 2020, we processed 25,978 samples using random pooling (n = 6,012; 23.1%) or questionnaire-based pooling (n = 19,966; 76.9%). The overall prevalence of SARS-CoV-2 was 0.9% (n = 238). Pool positivity (14.6% vs. 1.2%) and individual SARS-CoV-2 prevalence (3.4% vs. 0.1%) were higher in the random pooling group than in the questionnaire group. The average number of PCR tests needed to obtain the individual result for one participant was 0.27 tests in the random pooling group, as compared to 0.09 in the questionnaire-based pooling group, leading to a laboratory capacity increase of 73% and 91%, respectively, as compared to single PCR testing. Conclusions: Strategies that combine pool testing with a questionnaire-based risk stratification can increase laboratory testing capacities for COVID-19 and might be important tools, particularly in resource-constrained settings.

Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry is a powerful diagnostic technique for rapid and accurate identification of bacteria and fungi from clinical specimens. However, many high-consequence pathogens, such as potential bioterrorism agents (e.g. Bacillus anthracis, Yersinia pestis), cannot be detected reliably if conventional databases are used for MALDI-TOF analysis [ [1] Tracz D.M. Tyler A.D. Cunningham I. Antonation K.S. Corbett C.R. Custom database development and biomarker discovery methods for MALDI-TOF mass spectrometry-based identification of high-consequence bacterial pathogens. J Microbiol Methods. 2017; 134: 54-57 Crossref PubMed Scopus (11) Google Scholar ]. Early detection is key to decrease the risk of laboratory-acquired infections. If clinical samples are processed in a routine biosafety level (BSL) 2 laboratory, specific precautions for BSL 3/4 pathogens are not employed routinely at all work stations, and workers may get infected through direct contact or exposure to aerosols before the correct identification of these pathogens is established [ [2] Singh K. Laboratory-acquired infections. Clin Infect Dis. 2009; 49: 142-147 Crossref PubMed Scopus (122) Google Scholar ]. Hence, diagnostic procedures that allow for rapid pathogen identification may substantially decrease exposure of laboratory staff to biohazards. We would like to share recent experiences in our laboratory to illustrate the substantial benefits arising from direct pathogen detection in blood cultures and prompt MALDI-TOF identification using a specific database for highly pathogenic bacteria.

Epidemiology of Clostridium difficile is characterized by worldwide increase of C. difficile infections (CDI) and the emergence of new epidemic outbreak strains with the capacity for global spreading. Long-term local surveillance at the University of Saarland Medical Center between 2000 and 2013 shows that the incidence rate of laboratory-confirmed CDI was influenced by local epidemiology as well as by testing strategies. Since 2008, molecular typing of C. difficile was regularly performed for symptomatic hospitalized patients by surface-layer protein A sequence typing (slpAST), which is an established highly standardized technique for genotyping of C. difficile. The results were assigned to known ribotypes for better comparison to international data. It could be demonstrated that distribution of genotypes was different between age groups. Older patients were predominantly infected with ribotype 001 and 027, whereas ribotype 027 was not detected in the pediatric population. Molecular typing of German isolates sent to the advisory laboratory between 2011 and 2013 revealed that ribotype 027 is present with high percentages in most German regions except for the very North. In conclusion, optimized testing of all hospitalized patients with diarrhea should be generally implemented to avoid under-diagnosis of C. difficile infection. Ribotype 027 is highly prevalent in Germany, but its infections are restricted to older patients, while absent in children. Molecular typing of suspected hospital outbreaks and of patients with severe or recurrent disease may help to better understand virulence and epidemic spreading of C. difficile.

Objective.To establish the source and contamination routes resulting in positive clinical and surveillance microbiological cultures with carbapenem-resistant, GIM-1 metallo-β-lactamase–positiveAcinetobacter pitiiandAcinetobacter radioresistensfrom 21 patients in 8 departmentsDesign.Retrospective, descriptive study.Setting.A 1,300-bed tertiary care academic medical facility consisting of 90 buildings linked by a pneumatic transport system (PTS).Methods.Microbiological workup of the cluster strains included matrix-assisted laser desorption/ionization time-of-flight species identification, phenotypic carbapenemase tests, polymerase chain reaction–based genotyping of carbapenemase, and pulsed-field gel electrophoresis. Outbreak management procedures were employed according to institutional regulations.Results.The rarity of GIM-1Acinetobacterspecies in the hospital and region, the lack of epidemiological links between patients, and the fact that in some patients the apparent colonization was clearly nonnosocomial prompted the suspicion of a pseudo-outbreak. Numerous environmental cultures were positive for GIM-1-positiveAcinetobacter(including archived sample requisition forms, PTS capsules, cultures from line-diverter and dispenser stations, and sterilized transport capsules following PTS delivery). Moreover, it was observed that condensation fluid from subterranean PTS tubing resulted in water entry in PTS capsules, possibly conferring specimen contamination. After extensive system disinfection, environmental surveys of the PTS were negative, and no further positive patient specimens were encountered.Conclusions.This is the first report of a PTS-associated pseudo-outbreak. The large number of falsely positive patient-related specimens in conjunction with the potential hazard of airborne and contact spread of multidrug-resistant microorganisms (in this case, GIM-1 carbapenem-resistantAcinetobacterspecies) underscores the need for implementation of infection control–based monitoring and operating procedures in a hospital PTS.