First Report of Human Urinary Tract Infection Caused by Lactococcus petauri.

Lactococcus petauri is a recently described species of the genus Lactococcus. It was reported as an etiological agent of piscine lactococcosis together with Lactococcus garvieae. L. garvieae was already described as an opportunistic pathogen in human infections, with a potential zoonotic role. This paper represents the first report of a human urinary tract infection caused by L. petauri. A 91-year-old man was admitted to the emergency department for a femur fracture consequent to a domestic accident. The fracture was reduced by surgery and a catheterized specimen urine culture revealed a high bacterial load sustained by Gram-positive cocci, identified by Vitek 2 compact as L. garvieae, and subsequently as L. petauri through Internal Transcribed spacer 16S-23S r-RNA amplification. The number of L. petauri infections in humans is expected to rise in the near future mainly due to diagnostic improvement. A dedicated survey on L. garvieae and L. petauri infections in humans should be performed to better understand their role as pathogens and as zoonotic agents.

Characterization of vB_Kpn_F48, a Newly Discovered Lytic Bacteriophage for Klebsiella pneumoniae of Sequence Type 101.

Resistance to carbapenems in Enterobacteriaceae, including Klebsiella pneumoniae, represents a major clinical problem given the lack of effective alternative antibiotics. Bacteriophages could provide a valuable tool to control the dissemination of antibiotic resistant isolates, for the decolonization of colonized individuals and for treatment purposes. In this work, we have characterized a lytic bacteriophage, named vB_Kpn_F48, specific for K. pneumoniae isolates belonging to clonal group 101. Phage vB_Kpn_F48 was classified as a member of Myoviridae, order Caudovirales, on the basis of transmission electron microscopy analysis. Physiological characterization demonstrated that vB_Kpn_F48 showed a narrow host range, a short latent period, a low burst size and it is highly stable to both temperature and pH variations. High throughput sequencing and bioinformatics analysis revealed that the phage is characterized by a 171 Kb dsDNA genome that lacks genes undesirable for a therapeutic perspective such integrases, antibiotic resistance genes and toxin encoding genes. Phylogenetic analysis suggests that vB_Kpn_F48 is a T4-like bacteriophage which belongs to a novel genus within the Tevenvirinae subfamily, which we tentatively named "F48virus". Considering the narrow host range, the genomic features and overall physiological parameters phage vB_Kpn_F48 could be a promising candidate to be used alone or in cocktails for phage therapy applications.

Diversity of capsular polysaccharide gene clusters in Kpc-producing Klebsiella pneumoniae clinical isolates of sequence type 258 involved in the Italian epidemic.

Strains of Klebsiella pneumoniae producing KPC-type beta-lactamases (KPC-Kp) are broadly disseminating worldwide and constitute a major healthcare threat given their extensively drug resistant phenotypes and ability to rapidly disseminate in healthcare settings. In this work we report on the characterization of two different capsular polysaccharide (CPS) gene clusters, named cpsBO-4 and cps207-2, from two KPC-Kp clinical strains from Italy belonging in sequence type (ST) 258, which is one of the most successful ST of KPC-Kp spreading worldwide. While cpsBO-4 was different from known 78 K-types according to the recently proposed typing schemes based on the wzi or wzc gene sequences, cps207-2 was classified as K41 by one of these methods. Bioinformatic analysis revealed that they were represented in the genomic sequences of KPC-Kp from strains of ST258 from different countries, and cpsBO-4 was also detected in a KPC-Kp strain of ST442 from Brazil. Investigation of a collection of 46 ST258 and ST512 (a single locus variant of ST258) clinical strains representative of the recent Italian epidemic of KPC-Kp by means of a multiplex PCR typing approach revealed that cpsBO-4 was the most prevalent type, being detected both in ST258 and ST512 strains with a countrywide distribution, while cps207-2 was only detected in ST258 strains with a more restricted distribution.