The Impact of COVID-19 on Multidrug-Resistant Bacteria at a Slovenian Tertiary Medical Center.

The COVID-19 pandemic has strained healthcare systems globally. Shortages of hospital beds, reassignment of healthcare workers to COVID-19-dedicated wards, an increased workload, and evolving infection prevention and control measures have potentially contributed to the spread of multidrug-resistant bacteria (MDRB). To determine the impact of the COVID-19 pandemic at the University Medical Center Ljubljana, a tertiary teaching hospital, we analyzed the monthly incidence of select bacterial species per patient from 2018 to 2022. The analysis was performed for all isolates and for MDRB isolates. The data were analyzed separately for isolates from all clinical samples, from blood culture only, and from clinical and surveillance samples. Our findings revealed an increased incidence density of patients with Enterococcus faecium, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa isolates from clinical samples during the COVID-19 period in the studied hospital. Notably, the incidence density of MDRB isolates-vancomycin-resistant E. faecium, extended-spectrum betalactamase-producing K. pneumoniae, and betalactam-resistant P. aeruginosa-from clinical samples increased during the COVID-19 period. There were no statistically significant differences in the incidence density of patients with blood culture MDRB isolates. We observed an increase in the overall MDRB burden (patients with MDRB isolates from both clinical and surveillance samples per 1000 patient days) in the COVID-19 period in the studied hospital for vancomycin-resistant E. faecium, carbapenem-resistant K. pneumoniae, and betalactam-resistant P. aeruginosa and a decrease in the methicillin-resistant S. aureus burden.

Peritonitis related to chronic peritoneal dialysis in Slovenian pediatric patients.

AIMS: Peritonitis is the most significant complication of chronic peritoneal dialysis (PD). We aimed to define the frequency and country-specific characteristics of peritonitis in Slovenian pediatric patients. MATERIALS AND METHODS: All 23 children and adolescents treated with PD at our center between November 1995 and December 2019 were included in the study. There were 15 boys (65.2%) and 8 girls (34.8%). The median age at PD start was 4.8 years (range: 0 - 16.8 years). Patient demographic data, PD modality, treatment duration, and PD-related infections were collected retrospectively by reviewing the patients' medical records and the microbiology database. Data on the number of peritonitis episodes, microbiology results, and treatment outcomes were of prime interest. RESULTS: 30 peritonitis episodes were registered. The incidence rate was 1/33 patient-months (0.35/year). Twelve patients never experienced peritonitis (52.2%). Gram-positive organisms were isolated in 52.9% (Staphylococcus aureus (4/18), Staphylococcus epidermidis (4/18)). Gram-negative isolates were present in 32.4% (Escherichia coli (4/11), Pseudomonas species (2/11)). Fungal peritonitis occurred in 2.9% and negative culture peritonitis in 11.8%. Initial empirical treatment with vancomycin and ceftazidime was successful in 89.5%. PD was discontinued in 2 patients (8.7%) because of fungal peritonitis and refractory peritonitis. CONCLUSION: Our results compare favorably with the published literature. Awareness of local patient and microbial characteristics is crucial for the successful treatment and prevention of PD-associated infections.

Evaluation of two rapid phenotypical tests-Alifax rapid AST colistin test and Rapid Polymyxin NP test-for detection of colistin resistance in Enterobacterales.

Our study evaluates the performance of two rapid phenotypical tests to detect colistin resistance in Enterobacterales: Alifax rapid AST colistin test using the HB&L system and Rapid Polymyxin NP test prepared in-house. A collection of well-characterized 53 colistin-susceptible and 66 colistin-resistantEnterobacterales isolates was used. The results obtained using both rapid tests were compared to the reference broth microdilution. Overall categorical agreement was 81.5% for Alifax test and 98.3% for Rapid Polymyxin NP test. Based on our results, the Rapid Polymyxin NP test is superior to the Alifax test that performed inadequate for Enterobacter spp.

Fulminant peritonitis presumably caused by Panton-Valentine leukocidin-positive Staphylococcus aureus in a girl on peritoneal dialysis.

Peritonitis is a significant complication of peritoneal dialysis (PD) and the most common cause of technique failure. Panton-Valentine leukocidin (PVL), a cytotoxin produced by certain strains of Staphylococcus aureus (SA), causes destruction of neutrophils, and is associated with severe invasive infections. We present a 2.5-year-old girl on PD, who presented suddenly with an unusually fulminant and protracted course of peritonitis. Only a few hours after the onset of clinical signs, septic shock developed. PVL-positive methicillin-sensitive SA (MSSA) was grown and initial empiric antibiotic treatment changed to flucloxacillin and rifampicin in order to minimize toxin production. In spite of adequate antibiotic treatment and PD-catheter removal, recovery was slow. No PD-related peritonitis in children associated with PVL-producing strains have been reported so far and no specific recommendation exists for treatment. We speculate that PVL contributed to the severity and outcome of peritonitis in our patient.

Uropathogenic Escherichia coli induces serum amyloid a in mice following urinary tract and systemic inoculation.

Serum amyloid A (SAA) is an acute phase protein involved in the homeostasis of inflammatory responses and appears to be a vital host defense component with protective anti-infective properties. SAA expression remains poorly defined in many tissues, including the urinary tract which often faces bacterial challenge. Urinary tract infections (UTIs) are usually caused by strains of uropathogenic Escherichia coli (UPEC) and frequently occur among otherwise healthy individuals, many of whom experience bouts of recurrent and relapsing infections despite the use of antibiotics. To date, whether SAA is present in the infected urothelium and whether or not the induction of SAA can protect the host against UPEC is unclear. Here we show, using mouse models coupled with immunofluorescence microscopy and quantitative RT-PCR, that delivery of UPEC either directly into the urinary tract via catheterization or systemically via intraperitoneal injection triggers the expression of SAA. As measured by ELISA, serum levels of SAA1/2 were also transiently elevated in response to UTI, but circulating SAA3 levels were only up-regulated substantially following intraperitoneal inoculation of UPEC. In in vitro assays, physiological relevant levels of SAA1/2 did not affect the growth or viability of UPEC, but were able to block biofilm formation by the uropathogens. We suggest that SAA functions as a critical host defense against UTIs, preventing the formation of biofilms both upon and within the urothelium and possibly providing clinicians with a sensitive serological marker for UTI.

Chloramphenicol- and tetracycline-resistant uropathogenic Escherichia coli (UPEC) exhibit reduced virulence potential.

It is well documented that uropathogenic Escherichia coli (UPEC) isolates resistant to nalidixic acid have reduced virulence potential. Our goal was to assess whether UPEC isolates resistant to chloramphenicol, tetracycline and streptomycin also exhibit reduced virulence potential. Among 110 human UPEC isolates, the prevalences of the virulence factors fimH, papC, papGII, papGIII, sfa/focDE, afa, hlyA, cnf1, usp, ibeA, fyuA, iroN, iucD, ireA, and K1 and K5 capsules as well as of pathotypes, phylogenetic groups, O antigens and a pathogenicity island (PAI) marker were compared between chloramphenicol-, tetracycline-, streptomycin- and, as a control, nalidixic acid-resistant and -susceptible strains. Our findings show that among human UPEC isolates, not only nalidixic acid-resistant but also chloramphenicol- and tetracycline-resistant isolates have reduced virulence potential compared with susceptible strains. To our knowledge, this is the first report of a statistically significant reduction in virulence traits among chloramphenicol- and tetracycline-resistant isolates.

High prevalence of multidrug resistance and random distribution of mobile genetic elements among uropathogenic Escherichia coli (UPEC) of the four major phylogenetic groups.

One hundred and ten UTI Escherichia coli strains, from Ljubljana, Slovenia, were analyzed for antibiotic resistances, mobile DNA elements, serotype, and phylogenetic origin. A high prevalence of drug resistance and multidrug resistance was found. Twenty-six percent of the isolates harbored a class 1 integron, while a majority of the strains (56%) harbored rep sequences characteristic of F-like plasmids. int as well as rep sequences were found to be distributed in a random manner among strains of the four major phylogenetic groups indicating that all groups have a similar tendency to acquire and maintain mobile genetic elements frequently associated with resistance determinants.