A self-sterilizing fluorescent Nanocomposite as versatile material with broad-spectrum Antibiofilm features

Hematogenous spread of infections from colonized central intravenous catheters or central lines is a long-recognized problem with infection rates of 2 and 6.8 per 1000 days, respectively. Besides, removal of severe microbial colonization of implanted biomaterials is still a challenge and usually requires invasive operations. Hence, on demand self-sterilizing materials are required to avoid explant of colonized biomaterials and improve patient compliance. Moreover, photoluminescence is needed to make trackable biomaterials, which can be easily monitored upon implanting them in the body. Here, we propose the incorporation of near infrared (NIR) sensitive red-emitting carbon nanodot (CDs) into a polymeric matrix to give rise to innovative biomaterials with self-tracking and photothermal antimicrobial abilities. We obtain a material which can be processed to obtain medical devices using different techniques, among which, for instance, electrospinning. Herein, a proof-of-concept preparation of electrospun scaffolds is reported as it is highly desired in biomedical applications. Beside to confer imaging properties to the scaffold, that would allow an easy control over the in vivo positioning of implanted biomaterials as well as its degradation state and grade of integration with the surrounding native tissues, thanks to the capability to convert NIR light into local heat CDs can be exploited to exert broad-spectrum antimicrobial effect toward several pathogens. The rise in temperature can be easily modulated by controlling the irradiation time to achieve both an in vitro self-sterilization of the device and eventually in vivo destabilization of the microbial colonization. This innovative biomaterial could successfully inhibits biofilm formation and might be used as a powerful tool to treat antibiotic-resistant nature of biofilm-related infections in implanted medical devices

Sherris - Microbiologia Medica

Il testo di Sherris “Medical Microbiology”, giunto oggi alla sua sesta edizione, continua a rappresentare, a livello internazionale, un testo cardine per lo studio della Microbiologiamedica sia nel Corso di Medicina e Chirurgia sia nell’ambito della formazionespecialistica. La prima edizione di questo testo venne pubblicata nel 1976 da John C. Sherris, Professore Emerito di Microbiologia, noto per gli studi sulle resistenze batteriche agli antibioticied il rapido evolversi delle Scienze Mediche ed in particolare della Microbiologia ha resonecessari numerosi aggiornamenti che hanno portato alla attuale sesta edizione. Abbiamo partecipato con entusiasmo alla prima edizione italiana e con altrettanto entusiasmopartecipiamo alla seconda, sempre convinti del valore didattico del testo. Il libro è adatto a studenti che frequentano corsi di Microbiologia di base, poiché fornisce una descrizione completa e dettagliata degli agenti di infezione: classificazione, struttura, replicazion e malattia, ma anche a studenti che frequentano corsi di Microbiologia Clinica, in quanto tratta di diagnosi, prevenzione e terapia. Un rinnovato ringraziamento all’Editore Dr. Antonio Diomaiuta la cui stima ed amicizia ha reso il lavoro di noi tutti agevole ed efficiente

Arginine-Rich Peptidomimetic Ampicillin/Gentamicin Conjugate To Tackle Nosocomial Biofilms: A Promising Strategy To Repurpose First-Line Antibiotics

: Combined therapy with penicillins and aminoglycosides has been proved beneficial to address many persistent bacterial infections with possible synergistic effects. However, the different pharmacokinetic profiles of these two antibiotic classes may not guarantee a concerted spatio-temporal delivery at the site of action, decreasing the efficacy of this combination and promoting resistance. Herein, we propose a multifunctional antibiotic-polymer conjugate, designed to colocalize ampicillin and gentamicin to tackle persistent biofilm infections. The two antibacterial molecules were grafted along with the amino acid l-arginine to a biocompatible polymer backbone with peptidomimetic hydrophilic structure, obtaining the antimicrobial poly(argilylaspartamide-co-aspartic) acid-ampicillin, gentamicin (PAA-AG) conjugate. The PAA-AG conjugate displayed excellent biocompatibility on human cell lines if compared with free drugs, potentially enlarging their therapeutic window and safety, and suitable mucoadhesive characteristics which may help local treatments of mucosal infections. Studies on planktonic cultures of clinical and reference strains of S. aureus, P. aeruginosa, and E. coli revealed that PAA-AG holds a broad-spectrum antibacterial efficacy, revealing high potency in inhibiting the growth of the tested strains. More interestingly, PAA-AG exhibited excellent antibiofilm activity on both Gram+ and Gram- communities, showing inhibition of their formation at subMIC concentrations as well as inducing the regression of mature biofilms. Given the high biocompatibility and broad antibiofilm efficacy, combined with the opportunity for synchronous co-delivery, the PAA-AG conjugate could be a valuable tool to increase the success of ampicillin/gentamicin-based antibiotic multitherapy

MRSA ST22-IVa (EMRSA-15 clone) in Palermo, Italy

Summary: Epidemic spread of methicillin-resistant Staphylococcus aureus (MRSA) strains carrying the Staphylococcal Chromosomal Cassettes (SCC) mec type IV is being increasingly reported in many geographical areas. A survey to determine the prevalence and characteristics of MRSA SCCmec IV isolates identified in four general hospitals in Palermo, Italy, was carried out. During the period February–June 2009, SCCmec type IVa has been found in 12 out of 94 isolates. Nine isolates from all hospitals and all strains from a NICU outbreak occurring in the same period were attributed with the ST22-IVa (EMRSA-15) clone. In our setting, due to the changing MRSA epidemiology, detection of SCCmec IV could be poorly predictive of CA-MRSA. Keywords: MRSA, ST22-IVA, EMRSA-15, Epidemiology, Molecular typin

Candida parapsilosis Infection:A Multilocus Microsatellite Genotyping-Based Survey Demonstrating an Outbreak in Hospitalized Patients

Microsatellite analysis identifies specific genotypes and the genetic relationship between strains. Our objective was to analyze the genotypes of C. parapsilosis strains isolated on different wards of aTertiary- Referral University Center. We evaluated 70 C. parapsilosis strains in total, isolated from samples of patients admitted to five different wards over two years (January 2015-December 2016). Eight microsatellite markers were selected, and two multiplex PCR assays were set up for microsatellite analysis. The 70 strains, examined at eight microsatellite loci, showed 46 different multilocus genotypes profiles. A total of 74 alleles were detected, with an average of 9.25 alleles per locus. The most variable loci were CP6 and CP4, with 20 and 15 alleles, respectively. Four clusters were detected in four out of five wards. A significant cluster that involved 16 patients in the General Surgery department was also found in two patients who had been transferred to the General Medicine ward. Two multiplex PCRs allowed us to minimize costs, define genotypes and study the isolates’ genetic diversity with extreme accuracy, demonstrating the high discriminative power of the microsatellite markers. Molecular epidemiology constitutes an appropriate tool for evaluating horizontal transmission of C. parapsilosis in different clinical settings. Microsatellite genotyping and the utilization of Bruvo’s genetic distance are suitable for detecting and appraising nosocomial fungal infections

Polyclonal non multiresistant Staphylococcus aureus isolates from clinical cases of infection occurring in Palermo, Italy, during a one-year surveillance period.

BACKGROUND: The evolving epidemiology of methicillin resistant Staphylococcus aureus (MRSA) is characterized by the emergence of infections caused by non multiresistant MRSA carrying staphylococcal chromosomal cassette (SCC)mec IV or V in the healthcare settings. A molecular epidemiological analysis of non multiresistant MRSA isolates from four acute general hospitals was performed in Palermo, Italy, during a one year period. METHODS: For the purpose of the study, MRSA isolates were defined as non multiresistant when they were susceptible to at least three classes of non beta-lactam antibiotics. Seventy-five isolates were submitted to antimicrobial susceptibility testing, multilocus sequence typing (MLST) and polymerase chain reaction (PCR) for SCCmec, accessory gene regulator (agr) groups, arginine catabolic mobile element (ACME) and Panton Valentine leukocidin (PVL) toxin genes. For epidemiological typing, Multiple-Locus Variable-Number Tandem Repeat Fingerprinting (MLVF) was performed on all isolates and pulsed field gel electrophoresis (PFGE) on ST8 isolates. RESULTS: Non multiresistant MRSA isolates were isolated from all hospitals. Resistances to ciprofloxacin, macrolides and tetracycline were the most prevalent. MLST attributed 46 isolates with ST22, 13 with ST8, eight with ST1, three with ST50 and three with ST398. SCCmec type IV was found in all isolates. PVL was detected in one ST22 isolate. All isolates tested negative for the ACME element. MLVF identified 31 different patterns, some subtype clusters ranging in size between two and 22 isolates. The closely related PFGE patterns of the ST8 isolates differed from USA300. CONCLUSIONS: A polyclonal circulation of non multiresistant MRSA along with blurring of boundaries between healthcare associated (HA)-MRSA and community associated (CA)-MRSA appear to be occurring in our epidemiological setting. A better understanding of spread of MRSA with the support of molecular typing can provide invaluable information in the epidemiological, microbiological and clinical field

Cluster of Legionnaires’ Disease in an Italian Prison

Background: Legionella pneumophila (Lp) is the most common etiologic agent causing Legionnaires’ Disease (LD). Water systems offer the best growth conditions for Lp and support its spread by producing aerosols. From 2015 to 2017, the Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis of Palermo monitored the presence of Lp in nine prisons in Western Sicily. During this investigation, we compared Lp isolates from environmental samples in a prison located in Palermo with isolates from two prisoners in the same prison. Methods: We collected 93 water samples from nine Sicilian prisons and the bronchoalveolar lavages (BALs) of two prisoners considered cases of LD. These samples were processed following the procedures described in the Italian Guidelines for the Prevention and Control of Legionellosis of 2015. Then, genotyping was performed on 19 Lp colonies (17 from water samples and 2 from clinical samples) using the Sequence-Based Typing (SBT) method, according to European Study Group for Legionella Infections (ESGLI) protocols. Results: Lp serogroup (sg) 6 was the most prevalent serogroup isolated from the prisons analyzed (40%), followed by Lp sg 1 (16%). Most of all, in four penitentiary institutions, we detected a high concentration of Lp >104 Colony Forming Unit/Liter (CFU/L). The environmental molecular investigation found the following Sequence Types (STs) in Lp sg 6: ST 93, ST 292, ST 461, ST 728, ST 1317 and ST 1362, while most of the isolates in sg 1 belonged to ST 1. We also found a new ST that has since been assigned the number 2451 in the ESGLI-SBT database. From the several Lp sg 1 colonies isolated from the two BALs, we identified ST 2451. Conclusions: In this article, we described the results obtained from environmental and epidemiological investigations of Lp isolated from prisons in Western Sicily. Furthermore, we reported the first cluster of Legionnaires’ in an Italian prison and the molecular typing of Lp sg 1 from one prison’s water system and two BALs, identified the source of the contamination, and discovered a new ST