Stefanie Kampmeier

Weekly screening supports terminating nosocomial transmissions of vancomycin-resistant enterococci on an oncologic ward – a retrospective analysis

BackgroundTo investigate the impact of weekly screening within the bundle of infection control measures to terminate vancomycin-resistant enterococci (VRE) transmissions on an oncologic ward.MethodsA cluster of 12 VRE colonisation and five infections was detected on an oncologic ward between January and April 2015. Subsequently, the VRE point prevalence was detected and, as part of a the bundle of infection control strategies to terminate the VRE cluster, we isolated affected patients, performed hand hygiene training among staff on ward, increased observations by infection control specialists, intensified surface disinfection, used personal protective equipment and initiated an admission screening in May 2015. After a further nosocomial VRE infection in August 2015, a weekly screening strategy of all oncology patients on the respective ward was established while admission screening was continued. Whole genome sequencing (WGS)-based typing was applied to determine the clonal relationship of isolated strains.ResultsInitially, 12 of 29 patients were VRE colonised; of these 10 were hospital-acquired. During May to August, on average 7 of 40 patients were detected to be VRE colonised per week during the admission screening, showing no significant decline compared to the initial situation. WGS-based typing revealed five different clusters of which three were due to vanB- and two vanA-positive enterococci. After an additional weekly screening was established, the number of colonised patients significantly declined to 1/53 and no further nosocomial cases were detected.ConclusionsWeekly screening helped to differentiate between nosocomial and community-acquired VRE cases resulting in earlier infection control strategies on epidemic situations for a successful termination of nosocomial VRE transmissions.

Whole-Genome Sequencing Elucidates Epidemiology of Nosocomial Clusters of Acinetobacter baumannii

ABSTRACT We characterized two epidemiologically similar Acinetobacter baumannii clusters from two separate intensive care units (ICU) using core genome multilocus sequence typing. Clonal spread was confirmed in ICU-1 (12 of 14 isolates shared genotypes); in ICU-2, all genotypes (13 isolates) were diverse, thus excluding transmissions and enabling adequate infection control measures.

Control of Multidrug-Resistant Pseudomonas aeruginosa in Allogeneic Hematopoietic Stem Cell Transplant Recipients by a Novel Bundle Including Remodeling of Sanitary and Water Supply Systems

Background Infections by multidrug-resistant Pseudomonas aeruginosa (MDRPa) are an important cause of morbidity and mortality in patients after allogeneic hematopoietic stem cell transplantation (HSCT). Humid environments can serve as a reservoir and source of infection by this pathogen. To minimize the risk of infection from these reservoirs, we performed extensive remodeling of sanitation and water installations as the focus of our hygiene bundle. Methods During the reconstruction of our transplantation unit (April 2011-April 2014) we implemented several technical modifications to reduce environmental contamination by and subsequent spreading of MDRPa, including a newly designed shower drain, disinfecting siphons underneath the sinks, and rimless toilets. During a 3-year study period (2012-2014), we tracked the number of patients affected by MDRPa (colonized and/or infected) and the outcome of infected patients, and monitored the environmental occurrence of this pathogen. We further performed whole-genome sequencing of nosocomial MDRPa strains to evaluate genotypic relationships between isolates. Results Whereas 31 (9.2%; 18 colonized, 13 infected) patients were affected in 2012 and 2013, the number decreased to 3 in 2014 (17%; 3 colonized, 0 infected). Lethality by MDRPa similarly decreased from 3.6% to 0%. Environmental detection of MDRPa decreased in toilets from 18.9% in 2012-2013 to 6.1% in the following year and from 8.1% to 3.0%, respectively, in shower outlets. Whole-genome sequencing showed close relationships between environmental and patient-derived isolates. Conclusions Hospital construction measures aimed at controlling environmental contamination by and spread of MDRPa are effective at minimizing the risk of highly lethal MDRPa infections.

Norovirus infections in a tertiary care centre − individual cases do not necessarily lead to an outbreak

BACKGROUND Norovirus is responsible for the majority of gastroenteritis outbreaks within healthcare settings. Routes of spread include foodborne-, waterborne- and especially person-to-person transmissions. OBJECTIVE We investigated the overall attack rate of norovirus, within and outside outbreak situations, transmitted via patient-to-patient contact in a tertiary care centre from January 2012 to March 2015. STUDY DESIGN We monitored exposed asymptomatic patients next to infectious patients for the development of symptoms of acute gastroenteritis following exposure. RESULTS We detected 102 patients with contact to 94 infectious patients. Of these only 11 patients developed typical norovirus symptoms after exposure while 91 patients remained asymptomatic. Total secondary attack rate was only 10.8%. CONCLUSIONS Patient-to-patient transmission of norovirus is potentially overestimated within clinical settings. Future prevention strategies should consider personal risk factors of exposed patients.

Defining Multidrug Resistance of Gram-Negative Bacteria in the Dutch–German Border Region—Impact of National Guidelines

Preventing the spread of multidrug-resistant Gram-negative bacteria (MDRGNB) is a public health priority. However, the definition of MDRGNB applied for planning infection prevention measures such as barrier precautions differs depending on national guidelines. This is particularly relevant in the Dutch–German border region, where patients are transferred between healthcare facilities located in the two different countries, because clinicians and infection control personnel must understand antibiograms indicating MDRGNB from both sides of the border and using both national guidelines. This retrospective study aimed to compare antibiograms of Gram-negative bacteria and classify them using the Dutch and German national standards for MDRGNB definition. A total of 31,787 antibiograms from six Dutch and four German hospitals were classified. Overall, 73.7% were no MDRGNB according to both guidelines. According to the Dutch and German guideline, 7772/31,787 (24.5%) and 4586/31,787 (12.9%) were MDRGNB, respectively (p < 0.0001). Major divergent classifications were observed for extended-spectrum β-lactamase (ESBL) -producing Enterobacteriaceae, non-carbapenemase-producing carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa and Stenotrophomonas maltophilia. The observed differences show that medical staff must carefully check previous diagnostic findings when patients are transferred across the Dutch–German border, as it cannot be assumed that MDRGNB requiring special hygiene precautions are marked in the transferred antibiograms in accordance with both national guidelines.

High prevalence of MRSA and multi-resistant gram-negative bacteria in refugees admitted to the hospital—But no hint of transmission

With high numbers of refugees arriving in Europe uncertainty exists as to whether multidrug-resistant organisms are imported into the healthcare system. In our study, we identified 383 refugee-inpatients admitted to the University Hospital Münster, Germany between September 2015 and September 2016. For this patient cohort screening for Methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Gram-negative bacteria (MDR-GNB) and Vancomycin-resistant enterococci (VRE) was recommended in our institution. Until May 2016 pre-emptive isolation was applied to all refugee-inpatients until the exclusion of these multidrug-resistant organisms. MRSA were found in 34 refugee-patients (9.8%), MDR-GNB in 25 refugee-patients (12.9%) and VRE in none of the refugee patients. We did not find any strains carrying carbapenemases. Whole genome sequencing (WGS) data demonstrated that the respective isolates were genetically heterogeneous and revealed no transmission of refugee-patient isolates to other patients. We therefore omitted pre-emptive isolation as an infection control measure for this group of patients. Furthermore, molecular typing did not show evidence for nosocomial transmission from refugee-patients to other patients. Standard hygiene measures successfully prevented the transmission of refugee-patient isolates to other patients and as a result introduction into the healthcare system. This underlines that any multidrug-resistant organisms present within this cohort are not of any extraordinary concern for health systems.

The 2011 German Enterohemorrhagic Escherichia Coli O104:H4 Outbreak—The Danger Is Still Out There

Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin (Stx) producing bacteria causing a disease characterized by bloody (or non-bloody) diarrhea, which might progress to hemolytic uremic syndrome (HUS). EHEC O104:H4 caused the largest ever recorded EHEC outbreak in Germany in 2011, which in addition showed the so far highest incidence rate of EHEC-related HUS worldwide. The aggressive outbreak strain carries an unusual combination of virulence traits characteristic to both EHEC-a chromosomally integrated Stx-encoding bacteriophage, and enteroaggregative Escherichia coli-pAA plasmid-encoded aggregative adherence fimbriae mediating its tight adhesion to epithelia cells. There are currently still open questions regarding the 2011 EHEC outbreak, e.g., with respect to the exact molecular mechanisms resulting in the hypervirulence of the strain, the natural reservoir of EHEC O104:H4, and suitable therapeutic strategies. Nevertheless, our knowledge on these issues has substantially expanded since 2011. Here, we present an overview of the epidemiological, clinical, microbiological, and molecular biological data available on the 2011 German EHEC O104:H4 outbreak.

Whole genome sequencing reveals a prolonged and spatially spread nosocomial outbreak of Panton–Valentine leucocidin-positive meticillin-resistant Staphylococcus aureus (USA300)

BACKGROUND Whole genome sequencing (WGS) helps to better investigate the transmission and characterization of meticillin-resistant Staphylococcus aureus (MRSA) strains. AIM We describe the detection and unfolding of a prolonged and spatially distributed nosocomial outbreak of Panton-Valentine leucocidin (PVL)-positive MRSA ST8 (USA300). METHODS The outbreak was detected by the combination of whole genome sequence (WGS)-based typing, which is implemented for routine surveillance of multidrug-resistant bacteria in our institution, and in-depth epidemiological investigation. To investigate the source, processes were observed and environmental sampling performed. To contain the outbreak, regular and direct personal contact with the healthcare workers (HCWs) was maintained and staff education implemented. FINDINGS The outbreak took place between October 2016 and November 2017 and included five patients who were treated in two different departments as inpatients and outpatients; three were infected, two were colonized. Additionally, three HCWs carried the outbreak strain. The strain was not found in the hospital environment. Only through non-mediated communication did the source become apparent. Decolonization of HCWs and infection control measures led to a resolution of the outbreak. CONCLUSION WGS helped to reveal an outbreak that otherwise might have stayed undetected. Nonetheless, epidemiological investigation is needed to trace the nosocomial transmission. The importance of personal communication in infection control cannot be overstated.

Infection of exposed patients during norovirus outbreaks: are there predictive parameters?

BACKGROUND Norovirus outbreak management comprises isolation and cohorting of patients. In this context, exposed patients are preferably cohorted separately from symptomatic and unexposed asymptomatic patients, since they potentially develop symptoms of norovirus gastroenteritis. Whether routinely examined clinical or laboratory parameters can help to predict occurrence of gastroenteritis symptoms in those patients has not yet been examined. AIM To evaluate routinely examined clinical and laboratory parameters as predictive values for the development of norovirus symptoms in exposed patients during outbreaks. METHODS Exposed patients during norovirus outbreaks were observed throughout a two-year period in the university hospital of Muenster. The development of laboratory-confirmed norovirus gastroenteritis symptoms was examined in exposed patients, and clinical as well as laboratory parameters prior to onset of the outbreak were compared in exposed symptomatic and asymptomatic patients. FINDINGS We detected 42 exposed patients within 10 outbreaks. Of these, 33 remained asymptomatic, whereas nine patients developed norovirus gastroenteritis. Exposed symptomatic patients were significantly older (50±10.51 vs 28±4.68 years), had significantly higher blood sodium concentration (142.5±1.48 vs 138.8±0.47mmol/L) and higher systolic blood pressure (119.3±3.84 vs 108.5±2.41mmHg). Development of symptoms among exposed patients was significantly associated with blood type O (75% vs 20%). CONCLUSION In order to minimize patient-to-patient transmission within norovirus outbreaks in hospital, risk stratification of exposed patients is helpful. To achieve this, routinely detected clinical and laboratory parameters can be useful to predict development of symptoms in these patients.

Evaluation of a Stenotrophomonas maltophilia bacteremia cluster in hematopoietic stem cell transplantation recipients using whole genome sequencing

BackgroundStenotrophomonas maltophilia ubiquitously occurs in the hospital environment. This opportunistic pathogen can cause severe infections in immunocompromised hosts such as hematopoietic stem cell transplantation (HSCT) recipients. Between February and July 2016, a cluster of four patients on the HSCT unit suffered from S. maltophilia bloodstream infections (BSI).MethodsFor epidemiological investigation we retrospectively identified the colonization status of patients admitted to the ward during this time period and performed environmental monitoring of shower heads, shower outlets, washbasins and toilets in patient rooms. We tested antibiotic susceptibility of detected S. maltophilia isolates. Environmental and blood culture samples were subjected to whole genome sequence (WGS)-based typing.ResultsOf four patients with S. maltophlilia BSI, three were found to be colonized previously. In addition, retrospective investigations revealed two patients being colonized in anal swab samples but not infected. Environmental monitoring revealed one shower outlet contaminated with S. maltophilia. Antibiotic susceptibility testing of seven S. maltophlia strains resulted in two trimethoprim/sulfamethoxazole resistant and five susceptible isolates, however, not excluding an outbreak scenario. WGS-based typing did not result in any close genotypic relationship among the patients’ isolates. In contrast, one environmental isolate from a shower outlet was closely related to a single patient’s isolate.ConclusionWGS-based typing successfully refuted an outbreak of S. maltophilia on a HSCT ward but uncoverd that sanitary installations can be an actual source of S. maltophilia transmissions.