Staphylococcusaureus bacteriuria (SABU) can occur in patients with S. aureus bacteremia (SAB). However, little is known on the (molecular) pathomechanisms of the renal passage of S. aureus. This review discusses the epidemiology and pathogenesis of SABU in patients with SAB and identifies knowledge gaps. The literature search was restricted to the English language. The prevalence of SABU in patients with SAB is 7.8%–39% depending on the study design. The main risk factor for SABU is urinary tract catheterization. SABU in SAB patients is associated with increased mortality. Given present evidence, hematogenous seeding—as seen in animal models—and the development of micro-abscesses best describe the translocation of S. aureus from blood to urine. Virulence factors that might be involved are adhesion factors, sortase A, and coagulase, among others. Other potential routes of bacterial translocation (eg, transcytosis, paracytosis, translocation via “Trojan horses”) were identified as knowledge gaps.

Dissemination of antimicrobial resistance (AMR) is a growing global public health burden. The aim of this study was to characterize AMR plasmid transmissions within a tertiary care hospital and identify relevant AMR plasmid transmission pathways. During an 18-month observation period, 540 clinical gram-negative multidrug-resistant bacterial (MDRB) isolates were collected during routine hospital surveillance and subjected to Pacific Biosciences long-read whole genome sequencing. Potential clonal transmissions were determined based on core genome multilocus sequence typing (cgMLST), and plasmid transmissions were detected using a novel real-time applicable tool for plasmid transmission detection. Potential transmissions were validated using epidemiological data. Among the 471 eligible MDRB isolates, we detected 1,539 plasmids; 84.41% of these were circularized. We identified 38 potential clonal transmissions in 24 clusters based on cgMLST and 121 potential plasmid transmissions in 24 clusters containing genetically related AMR plasmids. Among the latter clusters, 10 contained different multilocus sequence types (involving 2–38 isolates, median: 3 isolates), and nine contained multiple species (2–18 isolates, median: 4). Epidemiological data confirmed 19 clonal transmissions (in seven clusters) and an additional 12 plasmid transmissions (within eight plasmid clusters). Among these, we identified seven cases of intra-host and five patient-to-patient plasmid transmissions. We demonstrate that intra-host and patient-to-patient transmissions of AMR plasmids can be identified by combining long-read sequencing with real-time applicable tools during routine molecular surveillance. In addition, our study highlights that more than a decade of bacterial genomic surveillance missed at least one-third of all AMR transmission events due to plasmids. IMPORTANCE: Antimicrobial resistance (AMR) poses a significant threat to human health. Most AMR determinants are encoded extra-chromosomally on plasmids. Although current infection control strategies primarily focus on clonal transmission of multidrug-resistant bacteria, until today, AMR plasmid transmission routes are neither understood nor analyzed in the hospital setting. In our study, we simultaneously determined both clonal, that is, based on chromosomes, and AMR plasmid transmissions during routine molecular surveillance by combining long-read sequencing with a novel real-time applicable software tool and validated all potential transmission events with epidemiological data. Our analysis determined not only the yet unknown plasmid transmissions within healthcare facilities or within the community but also resulted, in addition to the clonal transmissions, in at least a third more transmissions due to AMR plasmids.

Plasmid transfer is one important mechanism how antimicrobial resistance can spread between different species, contributing to the rise of multidrug resistant bacteria (MDRB) worldwide. Here were present whole genome sequencing (WGS) data of two MDRB isolates, an Escherichia coli and a Klebsiella quasipneumoniae, which were isolated from a single patient. Detailed analysis of long-read sequencing data identified an identical F2:A-:B- lncFII plasmid containing bla_CTX-M-27 in both isolates, suggesting horizontal plasmid exchange between the two species. As the plasmid of the E. coli strain carried multiple copies of the resistance cassette, the genomic data correlated with the increased antimicrobial resistance (AMR) detected for this isolate. Our case report demonstrates how long-read sequencing data of MDRB can be used to investigate the role of plasmid mediate resistance in the healthcare setting and explain resistance phenotypes.

Since March 2020, the COVID-19 pandemic forced hospitals worldwide to intensify their infection control measures to prevent health care-associated transmission of SARS-CoV-2. The correct use of personal protective equipment, especially the application of masks, was quickly identified as priority to reduce transmission with this pathogen. Here, we report a nosocomial cluster of methicillin-resistant Staphylococcus aureus (MRSA) that occurred during the COVID-19 pandemic in a gynecology/obstetrics department, despite these intensified contact precautions. Five MRSA originating from clinical samples after surgical intervention led to an outbreak investigation. Firstly, this included environmental sampling of the operation theatre (OT) and, secondly, a point prevalence screening of patients and health care workers (HCW). All detected MRSA were subjected to whole genome sequencing (WGS) and isolate relatedness was determined using core genome multilocus sequence typing (cgMLST). WGS revealed one MRSA cluster with genetically closely related five patient and two HCW isolates differing in a single cgMLST allele at maximum. The outbreak was terminated after implementation of infection control bundle strategies. Although contact precaution measures, which are also part of MRSA prevention bundle strategies, were intensified during the COVID-19 pandemic, this MRSA outbreak could take place. This illustrates the importance of adherence to classical infection prevention strategies.

Background: Moraxella nonliquefaciens is a usually non-pathogenic biofilm-producing Gram-negative coccobacillus which may colonize the upper respiratory tract, rarely causing invasive disease. Although very rare, bloodstream infections caused by this organism have been described, showing often a fatal outcome. Here, we report the case of a pediatric cancer patient with bloodstream infection and sepsis due to M. nonliquefaciens showing full recovery after appropriate antibiotic treatment. Case presentation: A three-year-old boy with stage IV neuroblastoma was admitted for high-dose chemotherapy with autologous stem cell rescue after standard neuroblastoma treatment. Despite receiving antimicrobial prophylaxis with trimethoprim/sulfamethoxazole, acyclovir and amphothericin B, the patient presented with fever of up to 39.5 °C and neutropenia. Besides a chemotherapy-related mucositis and an indwelling Broviac catheter (removed), no infection focus was identified on physical examination. Moraxella nonliquafaciens was identified in blood cultures. After antibiotic treatment and neutrophil recovery, the patient was fit for discharge. Conclusions: The case described highlights the importance of an otherwise non-pathogenic microorganism, especially in immunosupressed cancer patients. It should be kept in mind that, although very infrequently, Moraxella nonliquefaciens may cause bloodstream infections that can be successfully treated with prompt focus identification and antibiotic therapy.

Background: Capnocytophaga canimorsus, a Gram-negative rod, belongs to the Flavobacteriaceae family and colonizes the oropharynx of dogs and cats. Infections with C. canimorsus are rare and can induce a systemic infection with a severe course of the disease. So far, only five case reports of C. canimorsus infections associated with Waterhouse–Friderichsen Syndrome (WFS) have been reported with only two of the patients having a history of splenectomy. Case presentation: Here, we report a fatal case of WFS due to C. canimorsus bacteremia and mycetal superinfection in a 61-year-old female asplenic patient. Despite extensive therapy including mechanical ventilation, antibiotic coverage with meropenem, systemic corticosteroids medication, vasopressor therapy, continuous renal replacement therapy, therapeutic plasma exchange, multiple transfusions of blood products and implantation of a veno-arterial extracorporeal membrane oxygenation the patient died 10 days after a dog bite. The autopsy showed bilateral hemorrhagic necrosis of the adrenal cortex and septic embolism to heart, kidneys, and liver. Diagnosis of C. canimorsus was prolonged due to the fastidious growth of the bacteria. Conclusions: The occurrence of a severe sepsis after dog bite should always urge the attending physician to consider C. canimorsus as the disease-causing pathogen. A therapeutic regimen covering C. canimorsus such as aminopenicillins or carbapenems should be chosen. However, despite maximum therapy, the prognosis of C. canimorsus-induced septic shock remains very poor. Asplenic or otherwise immunocompromised patients are at higher risk for a severe course of disease and should avoid exposure to dogs and cats and consider antibiotic prophylaxis after animal bite.