Skin dysbiosis and loss of microbiome site specificity in critically ill patients.

An increasing amount of evidence has linked critical illness with dysbiotic microbiome signatures in different body sites. The disturbance of the indigenous microbiota structures has been further associated with disease severity and outcome and has been suggested to pose an additional risk for complications in intensive care units (ICUs), including hospital-acquired infections. A better understanding of the microbial dysbiosis in critical illness might thus help to develop strategies for the prevention of such complications. While most of the studies addressing microbiome changes in ICU patients have focused on the gut, the lung, or the oral cavity, little is known about the microbial communities on the skin of ICU patients. Since the skin is the outermost organ and the first immune barrier against pathogens, its microbiome might play an important role in the risk management for critically ill patients. This observational study characterizes the skin microbiome in ICU patients covering five different body sites at the time of admission. Our results show a profound dysbiosis on the skin of critically ill patients, which is characterized by a loss of site specificity and an overrepresentation of gut bacteria on all skin sites when compared to a healthy group. This study opens a new avenue for further investigations on the effect of skin dysbiosis in the ICU setting and points out the need of strategies for the management of dysbiosis in critically ill patients.IMPORTANCEUnbalanced gut microbiota in critically ill patients has been associated with poor outcome and complications during the intensive care unit (ICU) stay. Whether the disturbance of the microbial communities in these patients is extensive for other body sites, such as the skin, is largely unknown. The skin not only is the largest organ of the body but also serves as the first immune barrier against potential pathogens. This study characterized the skin microbiota on five different body sites in ICU patients at the time of admission. The observed disturbance of the bacterial communities might help to develop new strategies in the risk management of critically ill patients.

Central-line associated bloodstream infections in intensive care units before and after implementation of daily antiseptic bathing with chlorhexidine or octenidine: a post-hoc analysis of a cluster-randomised controlled trial.

BACKGROUNDS: Antiseptic bathing did not reduce central-line (CL) associated bloodstream infection (CLABSI) rates in intensive care units (ICU) according to a recent cluster randomised controlled trial (cRCT). However, this analysis did not consider baseline infection rates. Our post-hoc analysis of this cRCT aimed to use a before-after comparison to examine the effect of daily bathing with chlorhexidine, octenidine or water and soap (control) on ICU-attributable CLABSI rates. METHODS: A post-hoc analysis of a multi-center cRCT was done. ICUs that did not yet perform routine antiseptic bathing were randomly assigned to one of three study groups applying daily bathing with 2% chlorhexidine-impregnated cloths, 0.08% octenidine wash mitts or water and soap (control) for 12 months. Baseline data was assessed 12 months before the intervention started when all ICUs routinely used water and soap. Poisson regression and generalised estimating equation models were applied to identify changes of CLABSI rates per 1000 CL days between intervention and baseline periods in each study group. RESULTS: The cRCT was conducted in 72 ICUs (24 per study group) including 76,139 patients in the baseline and 76,815 patients in the intervention period. In the chlorhexidine group, incidence density of CLABSI was reduced from 1.48 to 0.90 CLABSI per 1000 CL days comparing baseline versus intervention period (P = 0.0085). No reduction was observed in the octenidine group (1.26 versus 1.47 CLABSI per 1000 CL days, P = 0.8735) and the control group (1.20 versus 1.17, P = 0.3298). Adjusted incidence rate ratios (intervention versus baseline) were 0.63 (95%CI 0.46-0.87, P = 0.0172) in the chlorhexidine, 1.17 (95% CI 0.79-1.72, P = 0.5111) in the octenidine and 0.98 (95% CI 0.60-1.58, P = 0.9190) in the control group. Chlorhexidine bathing reduced CLABSI with gram-positive bacteria, mainly coagulase-negative staphylococci (CoNS). CONCLUSIONS: In this post-hoc analysis of a cRCT, the application of 2% chlorhexidine-impregnated cloths reduced ICU-attributable CLABSI. This preventive effect of chlorhexidine was restricted to CLABSI caused by gram-positive pathogens (CoNS). In contrast, 0.08% octenidine wash mitts did not reduce CLABSI rates in ICUs. Trial registration Registration number DRKS00010475, registration date August 18, 2016.

Clinical Evidence for the Use of Octenidine Dihydrochloride to Prevent Healthcare-Associated Infections and Decrease Staphylococcus aureus Carriage or Transmission-A Review.

BACKGROUND: The antiseptic agent octenidine dihydrochloride (OCT) is used for skin preparation, for Staphylococcus aureus decolonization, and within bundles for the prevention of catheter-related or surgical site infections (SSIs). Here, we review the evidence for the effects of OCT from clinical studies. METHODS: Review of studies published in the Medline, Scopus, and Cochrane databases until August 2022, performed in clinical settings and reporting on effects of OCT on S. aureus carriage/transmission, SSI prevention, and prevention of intensive care unit (ICU)-related or catheter-related bloodstream and insertion site infections. RESULTS: We included 31 articles. The success of S. aureus decolonization with OCT-containing therapies ranged between 6 and 87%. Single studies demonstrated that OCT application led to a reduction in S. aureus infections, acquisition, and carriage. No study compared OCT for skin preparation before surgical interventions to other antiseptics. Weak evidence for the use of OCT for pre-operative washing was found in orthopedic and cardiac surgery, if combined with other topical measures. Mostly, studies did not demonstrate that daily OCT bathing reduced ICU-/catheter-related bloodstream infections with one exception. CONCLUSIONS: There is a need to perform studies assessing the clinical use of OCT compared with other antiseptics with respect to its effectiveness to prevent nosocomial infections.

Split k-mer analysis compared to cgMLST and SNP-based core genome analysis for detecting transmission of vancomycin-resistant enterococci: results from routine outbreak analyses across different hospitals and hospitals networks in Berlin, Germany.

The increase of Vancomycin-resistant Enterococcus faecium (VREfm) in recent years has been partially attributed to the rise of specific clonal lineages, which have been identified throughout Germany. To date, there is no gold standard for the interpretation of genomic data for outbreak analyses. New genomic approaches such as split k-mer analysis (SKA) could support cluster attribution for routine outbreak investigation. The aim of this project was to investigate frequent clonal lineages of VREfm identified during suspected outbreaks across different hospitals, and to compare genomic approaches including SKA in routine outbreak investigation. We used routine outbreak laboratory data from seven hospitals and three different hospital networks in Berlin, Germany. Short-read libraries were sequenced on the Illumina MiSeq system. We determined clusters using the published Enterococcus faecium-cgMLST scheme (threshold ≤20 alleles), and assigned sequence and complex types (ST, CT), using the Ridom SeqSphere+ software. For each cluster as determined by cgMLST, we used pairwise core-genome SNP-analysis and SKA at thresholds of ten and seven SNPs, respectively, to further distinguish cgMLST clusters. In order to investigate clinical relevance, we analysed to what extent epidemiological linkage backed the clusters determined with different genomic approaches. Between 2014 and 2021, we sequenced 693 VREfm strains, and 644 (93 %) were associated within cgMLST clusters. More than 74 % (n=475) of the strains belonged to the six largest cgMLST clusters, comprising ST117, ST78 and ST80. All six clusters were detected across several years and hospitals without apparent epidemiological links. Core SNP analysis identified 44 clusters with a median cluster size of three isolates (IQR 2-7, min-max 2-63), as well as 197 singletons (41.4 % of 475 isolates). SKA identified 67 clusters with a median cluster size of two isolates (IQR 2-4, min-max 2-19), and 261 singletons (54.9 % of 475 isolates). Of the isolate pairs attributed to clusters, 7 % (n=3064/45 596) of pairs in clusters determined by standard cgMLST, 15 % (n=1222/8500) of pairs in core SNP-clusters and 51 % (n=942/1880) of pairs in SKA-clusters showed epidemiological linkage. The proportion of epidemiological linkage differed between sequence types. For VREfm, the discriminative ability of the widely used cgMLST based approach at ≤20 alleles difference was insufficient to rule out hospital outbreaks without further analytical methods. Cluster assignment guided by core genome SNP analysis and the reference free SKA was more discriminative and correlated better with obvious epidemiological linkage, at least recently published thresholds (ten and seven SNPs, respectively) and for frequent STs. Besides higher overall discriminative power, the whole-genome approach implemented in SKA is also easier and faster to conduct and requires less computational resources.

Understanding COVID-19 reporting behaviour to support political decision-making: a retrospective cross-sectional study of COVID-19 data reported to WHO.

OBJECTIVE: Daily COVID-19 data reported by WHO may provide the basis for political ad hoc decisions including travel restrictions. Data reported by countries, however, are heterogeneous and metrics to evaluate its quality are scarce. In this work, we analysed COVID-19 case counts provided by WHO and developed tools to evaluate country-specific reporting behaviours. METHODS: In this retrospective cross-sectional study, COVID-19 data reported daily to WHO from 3 January 2020 until 14 June 2021 were analysed. We proposed the concepts of binary reporting rate and relative reporting behaviour and performed descriptive analyses for all countries with these metrics. We developed a score to evaluate the consistency of incidence and binary reporting rates. Further, we performed spectral clustering of the binary reporting rate and relative reporting behaviour to identify salient patterns in these metrics. RESULTS: Our final analysis included 222 countries and regions. Reporting scores varied between -0.17, indicating discrepancies between incidence and binary reporting rate, and 1.0 suggesting high consistency of these two metrics. Median reporting score for all countries was 0.71 (IQR 0.55-0.87). Descriptive analyses of the binary reporting rate and relative reporting behaviour showed constant reporting with a slight 'weekend effect' for most countries, while spectral clustering demonstrated that some countries had even more complex reporting patterns. CONCLUSION: The majority of countries reported COVID-19 cases when they did have cases to report. The identification of a slight 'weekend effect' suggests that COVID-19 case counts reported in the middle of the week may represent the best data basis for political ad hoc decisions. A few countries, however, showed unusual or highly irregular reporting that might require more careful interpretation. Our score system and cluster analyses might be applied by epidemiologists advising policy makers to consider country-specific reporting behaviours in political ad hoc decisions.

Chlorhexidine and octenidine susceptibility of bacterial isolates from clinical samples in a three-armed cluster randomised decolonisation trial.

BACKGROUND: Routine use of chlorhexidine or octenidine for antiseptic bathing may have unintended consequences. Our analysis aimed to assess the phenotypic susceptibility of bacterial isolates from clinical samples to chlorhexidine and octenidine collected from intensive care units (ICU) that routinely used 2% chlorhexidine-impregnated wash cloths or 0.08% octenidine wash mitts (intervention) or water and soap (control) for daily patient care. METHODS: This study was conducted within the context of a three armed cluster-randomised controlled decolonisation trial (Registration number DRKS00010475, registration date August 18, 2016). Bacterial isolates were collected prior to and at the end of a 12-month-intervention period from patients with ≥ 3 days length of stay at an ICU assigned to one of two intervention groups or the control group. Phenotypic susceptibility to chlorhexidine and octenidine was assessed by an accredited contract research laboratory determining minimal inhibitory concentrations (MIC) as percentage of extraction solutions used. MIC were reported as estimated concentrations in µg/ml derived from the chlorhexidine and octenidine extraction solutions. Statistical analyses including generalized estimating equation models were applied. RESULTS: In total, 790 ICU-attributable bacterial isolates from clinical samples (e.g. blood, urine, tracheal aspirate) were eligible for all analyses. Pathogens included were Staphylococcus aureus (n = 155), coagulase-negative staphylococci (CoNS, n = 122), Escherichia coli (n = 227), Klebsiella spp. (n = 150) and Pseudomonas aeruginosa (n = 136). For all species, chlorhexidine and octenidine MIC did not increase from baseline to intervention period in the antiseptic bathing groups. For proportions of bacterial isolates with elevated chlorhexidine / octenidine MIC (≥ species-specific chlorhexidine / octenidine MIC50), adjusted incidence rate ratios (aIRR) showed no differences between the intervention groups and the control group (intervention period). CONCLUSION: We found no evidence for reduced phenotypic susceptibilities of bacterial isolates from clinical samples to chlorhexidine or octenidine in ICUs 12 months after implementation of routine antiseptic bathing with the respective substances.

Effect of antiseptic bathing with chlorhexidine or octenidine on central line-associated bloodstream infections in intensive care patients: a cluster-randomized controlled trial.

OBJECTIVES: Our study aimed to compare the effect of daily bathing with chlorhexidine, octenidine, or water and soap (routine care = control) on central line (CL)-associated bloodstream infection (CLABSI) rates in intensive care units (ICUs). METHODS: A multicentre cluster-randomized controlled trial was done with a 12-month intervention period from February 1, 2017 to January 31, 2018 (octenidine and routine care group) or from June 1, 2017 to May 31, 2018 (chlorhexidine group). Wards were randomly assigned to one of two decolonization regimes or routine care (control). Intervention included daily bathing with 2% chlorhexidine-impregnated cloths or 0.08% octenidine wash mitts for 12 months, whereas the control group used water and soap (routine care). The primary outcome was incidence density of CLABSI per 1000 CL days. Poisson regression and generalized estimating equation models were applied. RESULTS: A total of 72 ICUs with 76 815 patients (22 897 patients in the chlorhexidine group, 25 127 in the octenidine group, and 28 791 in the routine care group) were included. Incidence densities were 0.90 CLABSI per 1000 CL days (95% CI 0.67-1.19) in the chlorhexidine group, 1.47 (95% CI 1.17-1.81) in the octenidine group, and 1.17 (95% CI 0.93-1.45) in the routine care group. Adjusted incidence rate ratios of CLABSI were 0.69 (95% CI 0.37-1.22, p = 0.28) in the chlorhexidine group and 1.22 (95% CI 0.54-2.75, p = 0.65) in the octenidine group (compared with routine care). DISCUSSION: Antiseptic bathing with 2% chlorhexidine-impregnated cloths and 0.08% octenidine wash mitts lacks a significant preventive effect on CLABSI rates in ICUs. However, our trial has a high likelihood of being underpowered because CLABSI rates in the routine care group were approximately 40% lower than initially assumed.

Prevalence and risk factors of colonisation with vancomycin-resistant Enterococci faecium upon admission to Germany's largest university hospital.

Background: Hospital-acquired infections due to vancomycin-resistant enterococci (VRE) are emerging globally. The aims of our study were to estimate VRE colonisation prevalence in patients upon admission, to determine possible risk factors for VR E. faecium acquisition that already exist in the outpatient setting, and to monitor whether VRE-colonised patients developed a VRE infection during their current hospital stay. Methods: In 2014 and 2015, patients admitted to non-intensive care units were screened for rectal VRE carriage. The study patients filled out a questionnaire on potential risk factors. Analyses were restricted to VR E. faecium carriage. All patients with VRE colonisation were retrospectively monitored for infections with VRE during their current hospital stay. Results: In 4,013 enrolled patients, the VRE colonisation prevalence upon admission was 1.2% (n=48), and colonisation prevalence was 1.1% (n=45) for VR E. faecium. Only one VRE-colonised patient developed an infection with the detection of a VRE, among others. Colonisation with VR E. faecium was associated with current antibiotic use. Risk factors of VR E. faecium colonisation upon admission were increasing age, previous colonisation or infection with multidrug resistant organisms, sampling year 2015, and, within the previous six months, antibiotic exposure, a stay at a rehabilitation center, and a hospital stay. Conclusions: We observed that antibiotic treatment which occurred prior admission influenced VR E. faecium prevalence upon admission. Thus, wise antibiotic use in outpatient settings plays a major role in the prevention of VR E. faecium acquisition.

[The global measles crisis-a diversity of causes from armed conflicts to vaccination skepticism]. / Die globale Masernkrise ­ Ursachenvielfalt von bewaffneten Konflikten bis Impfskepsis.

BACKGROUND AND AIM: Despite a safe and effective vaccine being available for many years, the number of measles cases has been increasing again worldwide since 2018. Our report aims to identify putative reasons for this development. METHODS: We conducted a selective literature search. Further, current reports and data from the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), and the World Bank were evaluated. RESULTS: According to the WHO, Madagascar, the Ukraine, and Israel had the highest incidences of measles worldwide between 1 July 2018 and 30 June 2019. Measles outbreaks are a sign of inadequate vaccination rates caused by multiple structural and psychological barriers. Structural barriers to measles vaccination, such as a lack of routine vaccination programs, have been identified as the main cause of low measles vaccination rates, particularly in fragile countries e.g. due to armed conflicts, but also in some subpopulations of higher-income countries e.g. due to lacking resources for vaccination services. Psychological barriers leading to vaccination skepticism were prevalent mainly in developed countries with well-functioning health systems and a high standard of living. CONCLUSION: The reasons for the global measles crisis are manifold and in some cases have existed for decades. However, the consequences appear to be accumulating and have had a dramatic impact on case numbers since 2018. The goal of measles elimination and maintenance of the necessary vaccination programs is a constant challenge that requires strict and permanent compliance with WHO recommendations. The number of measles cases reported in Germany is still at a level above the key target for measles elimination specified in the national immunization plan. Timely and/or locally restricted as well as nationwide outbreaks continue to occur. Since infectious agents can be transmitted across borders, the international perspective is an essential component of national health policy in Germany.

Effects and feasibility of hyperthermic baths in comparison to exercise as add-on treatment to usual care in depression: a randomised, controlled pilot study.

BACKGROUND: Limitations of current therapy of depression highlight the need for an immediately available, easily implementable add-on treatment option with high acceptance from patients. Hyperthermic baths (HTB) are a form of balneotherapy with head-out-of-water-immersion in a hot pool or tub at 40 °C for 15-20 min. A prior study suggests that HTB added to usual depression care can have antidepressant effects. METHOD: Single-site, open-label randomised controlled 8-week parallel-group pilot study at a university outpatient clinic. 45 medically stable outpatients with moderate depression as determined by the 17-item Hamilton Depression Rating Scale (HAM-D) score ≥ 18 and a score ≥ 2 on item 1 (Depressed Mood) were recruited. They were randomised to twice weekly HTB (n = 22) or a physical exercise program (PEP) of moderate intensity (n = 23). Primary outcome measure was the change in HAM-D total score from baseline (T0) to the 2-week time point (T1). Linear regression analyses, adjusted for baseline values, were performed to estimate intervention effects on an intention-to-treat (ITT) and per-protocol (PP) principle. RESULTS: Forty-five patients (HTB n = 22; PEP n = 23) were analyzed according to ITT (mean age = 48.4 years, SD = 11.3, mean HAM-D score = 21.7, SD = 3.2). Baseline-adjusted mean difference after 2 weeks was 4.3 points in the HAM-D score in favor of HTB (p < 0.001). Compliance with the intervention and follow-up was far better in the HTB group (2 vs 13 dropouts). Per protocol analysis only showed superiority of HTB as a trend (p = 0.068). There were no treatment-related serious adverse events. Main limitation: the number of dropouts in the PEP group (13 of 23) was higher than in other trials investigating exercise in depression. Due to the high number of dropouts the effect in the ITT-analysis may be overestimated. CONCLUSIONS: HTB added to usual care may be a fast-acting, safe and easy accessible method leading to clinically relevant improvement in depression severity after 2 weeks; it is also suitable for persons who have problems performing exercise training. TRIAL REGISTRATION: German Clinical Trials Register (DRKS) with the registration number DRKS00011013 (registration date 2016-09-19) before onset of the study.

Incidence of healthcare-associated Clostridioides difficile infections and association with ward-level antibiotic consumption in a German university hospital: an ecological study.

OBJECTIVES: Clostridioides difficile infection (CDI) is one of the most important healthcare-associated infections. We aimed to describe the incidence density of healthcare-associated CDI (HA-CDI) in Germany's largest hospital and to identify associations with ward-level antimicrobial consumption. METHODS: We used surveillance data on CDI and antimicrobial consumption from 2014 to 2017 and analysed a potential association by means of multivariable regression analysis. RESULTS: We included 77 wards with 404998 admitted patients and 1850862 patient-days. Six hundred and seventy-one HA-CDI cases were identified, resulting in a pooled mean incidence density of 0.36/1000 patient-days (IQR = 0.34-0.39). HA-CDI incidence density on ICU and haematological-oncological wards was about three times higher than on surgical wards [incidence rate ratio (IRR) = 3.00 (95% CI = 1.96-4.60) and IRR = 2.78 (95% CI = 1.88-4.11), respectively]. Ward-level consumption of third-generation cephalosporins was the sole antimicrobial risk factor for HA-CDI. With each DDD/100 patient-days administered, a ward's HA-CDI incidence density increased by 2% [IRR = 1.02 (95% CI = 1.01-1.04)]. Other risk factors were contemporaneous community-associated CDI cases [IRR = 1.32 (95% CI = 1.07-1.63)] and CDI cases in the previous month [IRR = 1.27 (95% CI = 1.07-1.51)]. Furthermore, we found a significant decrease in HA-CDI in 2017 compared with 2014 [IRR = 0.68 (95% CI = 0.54-0.86)]. CONCLUSIONS: We confirmed that ward-level antimicrobial use influences HA-CDI and specifically identified third-generation cephalosporin consumption as a risk factor.

Admission prevalence of colonization with third-generation cephalosporin-resistant Enterobacteriaceae and subsequent infection rates in a German university hospital.

BACKGROUND: Many patients admitted to a hospital are already colonized with multi-drug resistant organisms (MDRO) including third-generation cephalosporin-resistant Enterobacteriaceae (3GCREB). The aim of our study was to determine the prevalence of rectal 3GCREB colonization at admission to a large German university hospital and to estimate infection incidences. In addition, risk factors for 3GCREB colonization were identified. MATERIALS/METHODS: In 2014 and 2015, patients were screened for rectal colonization with 3GCREB and filled out a questionnaire on potential risk factors at admission to a non-intensive care unit (non-ICU). All patients were retrospectively monitored for bacterial infections. Descriptive, univariable and multivariable logistic regression analyses were conducted to identify risk factors for 3GCREB colonization at admission. RESULTS: Of 4,013 patients included, 10.3% (n = 415) were rectally colonized with 3GCREB at admission. Incidence of nosocomial infections was 3.5 (95% CI 2.0-6.1) per 100 patients rectally colonized with 3GCREB compared to 2.3 (95% CI 1.8-3.0, P = 0.213) per 100 3GCREB negative patients. Independent risk factors for 3GCREB colonization were prior colonization / infection with MDRO (OR 2.30, 95% CI 1.59-3.32), prior antimicrobial treatment (OR 1.97, 95% CI 1.59-2.45), male sex (OR 1.38, 95% CI 1.12-1.70), prior travelling outside Europe (OR 2.39, 95% CI 1.77-3.22) and places of residence in the Berlin districts Charlottenburg-Wilmersdorf (OR 1.52, 95% CI 1.06-2.18), Friedrichshain-Kreuzberg (OR 2.32, 95% CI 1.44-3.74) and Mitte (OR 1.73, 95% CI 1.26-2.36). CONCLUSIONS: Admission prevalence of rectal colonization with 3GCREB was high, while infection incidence did not significantly differ between patients rectally colonized or not with 3GCREB at hospital admission. In consequence, hospitals should prioritize improvement of standard precautions including hand hygiene to prevent infections among all patients irrespective of their 3GCREB status at hospital admission.

Protective Effect of Dual-Strain Probiotics in Preterm Infants: A Multi-Center Time Series Analysis.

OBJECTIVE: To determine the effect of dual-strain probiotics on the development of necrotizing enterocolitis (NEC), mortality and nosocomial bloodstream infections (BSI) in preterm infants in German neonatal intensive care units (NICUs). DESIGN: A multi-center interrupted time series analysis. SETTING: 44 German NICUs with routine use of dual-strain probiotics on neonatal ward level. PATIENTS: Preterm infants documented by NEO-KISS, the German surveillance system for nosocomial infections in preterm infants with birth weights below 1,500 g, between 2004 and 2014. INTERVENTION: Routine use of dual-strain probiotics containing Lactobacillus acidophilus and Bifidobacterium spp. (Infloran) on the neonatal ward level. MAIN OUTCOME MEASURES: Incidences of NEC, overall mortality, mortality following NEC and nosocomial BSI. RESULTS: Data from 10,890 preterm infants in 44 neonatal wards was included in this study. Incidences of NEC and BSI were 2.5% (n = 274) and 15.0%, (n = 1631), respectively. Mortality rate was 6.1% (n = 665). The use of dual-strain probiotics significantly reduced the risk of NEC (HR = 0.48; 95% CI = 0.38-0.62), overall mortality (HR = 0.60, 95% CI = 0.44-0.83), mortality after NEC (HR = 0.51, 95% CI = 0.26-0.999) and nosocomial BSI (HR = 0.89, 95% CI = 0.81-0.98). These effects were even more pronounced in the subgroup analysis of preterm infants with birth weights below 1,000 g. CONCLUSION: In order to reduce NEC and mortality in preterm infants, it is advisable to add routine prophylaxis with dual-strain probiotics to clinical practice in neonatal wards.

The mother as most important risk factor for colonization of very low birth weight (VLBW) infants with extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E).

OBJECTIVES: This study aimed to determine the prevalence of and risk factors for colonization with extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) and methicillin-resistant Staphylococcus aureus (MRSA) in very low birth weight (VLBW; <1500 g) infants and their mothers. METHODS: This investigation was conducted in the perinatal centre at the Charité Berlin between May 2012 and June 2013. VLBW infants and their mothers were screened for colonization with ESBL-E and MRSA. Demographic and clinical data were obtained from the German nationwide surveillance system for nosocomial infections in VLBW infants (NEO-KISS) and used to perform univariate and multivariate analyses. RESULTS: Of 209 VLBW infants, 12 (5.7%) were colonized with ESBL-E. Eighteen of 209 (8.6%) ESBL-E-tested neonates were related to an ESBL-E-positive mother. Univariate analysis, strain typing and multivariate analysis (OR 7.4, 95% CI 2.1-26.7, P = 0.002) identified an ESBL-E-positive mother and maternal-neonatal transmission as a main source of colonization. The prevalence of MRSA was 2.3% (5 of 221) among VLBW infants. One of the 221 (0.5%) MRSA-tested neonates was related to an MRSA-positive mother. No risk factors for transmission of MRSA could be detected in this study. CONCLUSIONS: Our study demonstrated that maternal-neonatal transmission of ESBL-E from mother to child is an important risk factor for colonization of VLBW infants. As a consequence, routine ESBL-E screening of neonates and mothers should be considered as a means of reducing neonatal morbidity and mortality.

Biotin sulfoxide reductase contributes to oxidative stress tolerance and virulence in Salmonella enterica serovar Typhimurium.

Oxidative stress converts sulfur residues of molecules like biotin and methionine into their oxidized forms. Here we show that the biotin sulfoxide reductase BisC of Salmonella enterica serovar Typhimurium (S. Typhimurium) repairs both oxidized biotin and oxidized methionine. Exposure to H2O2 in vitro reduced survival of a S. Typhimurium ΔbisC mutant. Furthermore, replication of the ΔbisC mutant inside IFN-γ activated macrophages was reduced. In vitro tolerance of the mutant to H2O2 was restored by plasmids carrying either bisC or msrA; the latter encodes a methioinine sulfoxide reductase. In contrast, the proliferation defect inside IFN-γ activated macrophages was rescued by bisC but not by msrA. Thus growth of the ΔbisC mutant in IFN-γ activated macrophages required repair of oxidized biotin. Both the ΔbisC and a biotin auxotrophic (ΔbioB) mutant were attenuated in mice, suggesting that besides biotin biosynthesis, biotin repair was essential for virulence of S. Typhimurium in vivo. Attenuation of the ΔbisC mutant was more pronounced in 129 mice that produce a stronger oxidative response. These results show that BisC is essential for full virulence of Salmonella by contributing to the defence of S. Typhimurium against host-derived stress, and provides an attractive drug target since it is not present in mammals.

Methionine sulfoxide reductases are essential for virulence of Salmonella typhimurium.

Production of reactive oxygen species represents a fundamental innate defense against microbes in a diversity of host organisms. Oxidative stress, amongst others, converts peptidyl and free methionine to a mixture of methionine-S- (Met-S-SO) and methionine-R-sulfoxides (Met-R-SO). To cope with such oxidative damage, methionine sulfoxide reductases MsrA and MsrB are known to reduce MetSOs, the former being specific for the S-form and the latter being specific for the R-form. However, at present the role of methionine sulfoxide reductases in the pathogenesis of intracellular bacterial pathogens has not been fully detailed. Here we show that deletion of msrA in the facultative intracellular pathogen Salmonella (S.) enterica serovar Typhimurium increased susceptibility to exogenous H(2)O(2), and reduced bacterial replication inside activated macrophages, and in mice. In contrast, a ΔmsrB mutant showed the wild type phenotype. Recombinant MsrA was active against free and peptidyl Met-S-SO, whereas recombinant MsrB was only weakly active and specific for peptidyl Met-R-SO. This raised the question of whether an additional Met-R-SO reductase could play a role in the oxidative stress response of S. Typhimurium. MsrC is a methionine sulfoxide reductase previously shown to be specific for free Met-R-SO in Escherichia (E.) coli. We tested a ΔmsrC single mutant and a ΔmsrBΔmsrC double mutant under various stress conditions, and found that MsrC is essential for survival of S. Typhimurium following exposure to H(2)O(2,) as well as for growth in macrophages, and in mice. Hence, this study demonstrates that all three methionine sulfoxide reductases, MsrA, MsrB and MsrC, facilitate growth of a canonical intracellular pathogen during infection. Interestingly MsrC is specific for the repair of free methionine sulfoxide, pointing to an important role of this pathway in the oxidative stress response of Salmonella Typhimurium.