Stefania Stolfa

Probiotic administration has become common practice in neonatal intensive care units (NICUs) to prevent necrotizing enterocolitis (NEC) and promote gut health in preterm infants. While probiotics are generally considered safe, rare cases of probiotic-related sepsis have been reported. We present a case of Lactobacillus rhamnosus sepsis in a preterm infant, highlighting the challenges involved in its diagnosis. The infant developed symptoms of sepsis on the 13th day of probiotic treatment. Laboratory analyses, including MALDI-TOF, BioFire BCID2 panel, and whole-genome sequencing (WGS), helped confirm the diagnosis and the presence of Lactobacillus rhamnosus. In this case, accurately identifying the Lactobacillus rhamnosus strain proved challenging, as initial analyses using the Vitek 2 system yielded incorrect identifications. This highlights the limitations of automated systems in distinguishing closely related species, reinforcing the need for advanced molecular techniques to achieve precise strain identification and confirm a probiotic-related infection. Given these diagnostic complexities, it is crucial for clinicians to maintain a high index of suspicion for probiotic-related infections in cases of unexplained sepsis, as this awareness can prompt further diagnostic investigations to ensure accurate pathogen identification. The infant responded to ampicillin therapy, showing clinical improvement within 10 days and was discharged in good health at 67 days of life. This case underscores the importance of advanced molecular diagnostic methods to confirm probiotic-related infections and highlights the need for caution in administering probiotics to vulnerable populations, such as preterm infants. Clinicians must maintain a high index of suspicion for probiotic-associated sepsis in unexplained cases of infection and tailor antibiotic therapy based on susceptibility profiles. These findings emphasize the need for rigorous monitoring, appropriate probiotic strain selection, and optimized safety protocols in NICUs to mitigate potential risks.

Candida auris is an emerging yeast considered a serious threat to global health. We report the first case of C. auris candidemia in Southern Italy, characterized using whole genome sequencing (WGS), and compared with a second strain isolated from a patient who presented as C. auris-colonized following screening. The C. auris strain was isolated from clinical samples, identified via MALDI-TOF, and subjected to WGS. Antifungal susceptibility testing was performed using commercial broth microdilution plates, and resistance protein sequences were evaluated with TBLASTN-2.15.0. Following the initial C. auris isolation from patient A, active surveillance and environmental investigations were implemented for all ICU patients. Of the 26 ICU surfaces sampled, 46.1% tested positive for C. auris via real-time PCR. Screening identified a second patient (patient B) as C. auris-colonized. The phylogenetic characterization of strains from patients A and B, based on the D1/D2 region of the 28s rDNA and the internal transcribed spacer (ITS) region, showed high similarity with strains from Lebanon. SNP analysis revealed high clonality, assigning both strains to clade I, indicating a significant similarity with Lebanese strains. This case confirms the alarming spread of C. auris infections and highlights the need for stringent infection control measures to manage outbreaks.

This study describes two cases of bacteraemia sustained by a new putative Pannonibacter species isolated at the U.O.C. of Microbiology and Virology of the Policlinico of Bari (Bari, Italy) from the blood cultures of two patients admitted to the Paediatric Oncohaematology Unit. Pannonibacter spp. is an environmental Gram-negative bacterium not commonly associated with nosocomial infections. Species identification was performed using Sanger sequencing of the 16S rRNA gene and Whole-Genome Sequencing (WGS) for both strains. Genomic analyses for the two isolates, BLAST similarity search, and phylogeny for the 16S rDNA sequences lead to an assignment to the species Pannonibacter phragmitetus. However, by performing ANIb, ANIm, tetranucleotide correlation, and DNA-DNA digital hybridization, analyses of the two draft genomes showed that they were very different from those of the species P. phragmitetus. MALDI-TOF analysis, assessment of antimicrobial susceptibility by E-test method, and Analytical Profile Index (API) tests were also performed. This result highlights how environmental bacterial species can easily adapt to the human host and, especially in nosocomial environments, also gain pathogenic potential through antimicrobial resistance.

Legionnaires' disease is a severe form of pneumonia caused by the inhalation or aspiration of water droplets contaminated with Legionella pneumophila and other Legionella species. These bacteria are commonly found in natural habitats and man-made water systems. Legionnaires' disease is a significant public health problem, especially in healthcare settings where patients may be exposed to contaminated environmental sources. Nosocomial outbreaks have been reported worldwide, leading to high morbidity and mortality rates, and increased healthcare costs. This study aimed to compare, the clonal relationship of clinical L. pneumophila strains from two different hospitals with L. pneumophila strains isolated from the water supply. In the period from 2019 to 2021, clinical and environmental strains involved in three cases of legionellosis were compared by means of pulsed field gel electrophoresis and sequence based typing techniques. Our findings highlight the persistence of clonally distinct strains within each hospital examined. Furthermore, the L. pneumophila strains detected from hospital environmental sources were related to the clinical strains isolated, demonstrating the nosocomial origin of these cases. Therefore, it is important to implement more accurate surveillance systems both for epidemiological studies and to check the effectiveness of remediation procedures. (www.actabiomedica.it).