Emanuela Roscetto

Proton pump inhibitors as a risk factor for paediatric Clostridium difficile infection.

Aliment Pharmacol Ther 31, 754–759

Impact of Clostridium difficile Infection on Pediatric Inflammatory Bowel Disease

OBJECTIVES To determine the prevalence of and explore possible differences in the risk for and symptoms of Clostridium difficile infection between patients with and without inflammatory bowel disease (IBD). STUDY DESIGN Stool specimens from subjects with and without IBD were evaluated for the presence of C difficile toxins. Demographic information, diagnosis, anatomic location, disease activity, IBD therapy, hospitalizations, and antibiotic and proton pump inhibitor (PPI) exposures were recorded. RESULTS A total of 193 specimens were collected from 81 patients with IBD and 112 patients without IBD. The prevalence of C difficile infection was significantly greater in the patients with IBD than in those without IBD (P = .004; chi2 = 0.003; odds ratio = 3.3; 95% confidence interval = 1.5 to 7.6). In the patients with IBD, the prevalence of active disease was significantly greater in the C difficile-infected patients than in the uninfected patients (P < .0001). Colonic involvement was found in all patients with IBD. The specific type of IBD, IBD therapy, and antibiotic and PPI exposures that predisposed patients with IBD to C difficile infection were not identified, whereas hospitalization was significantly more frequent in the patients without IBD (P = .025). CONCLUSIONS Our findings indicate that in children, IBD is associated with an increased prevalence of C difficile infection. The specific risk factors reported in adults were not identified in these children, suggesting the possible involvement of other mechanisms for acquiring the pathogen.

MALDI-TOF mass spectrometry and microsatellite markers to evaluate Candida parapsilosis transmission in neonatal intensive care units.

Recent studies on outbreaks of Candida showed an increased incidence of bloodstream infections in neonatal intensive care units (NICUs) caused by C. parapsilosis species, highlighting the need for the proper identification and epidemiology of these species. Several systems are available for molecular epidemiological and taxonomic studies of fungal infections: pulsed-field gel electrophoresis (PFGE) represents the gold standard for typing, but is also one of the most lengthy and expensive, while simple sequence repeats (SSRs) is based on polymerase chain reaction (PCR) amplification and is, therefore, faster. Only recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to identify and type microorganisms involved in nosocomial outbreaks. In our study, 19 strains of C. parapsilosis isolated from the blood cultures of neonates admitted to the University Hospital Federico II were genotyped by the amplification of eight SSR markers and by MALDI-TOF MS. Electrophoretic and spectrometric profile results were compared in order to identify similarities among the isolates and to study microevolutionary changes in the C. parapsilosis population. The discriminatory power and the unweighted pair group method with arithmetic mean (UPGMA) dendrograms generated were compared in order to evaluate the correlation of the groups established by the analysis of the clusters by both methods. Both methods were rapid and effective in highlighting identical strains and studying microevolutionary changes in the population. Our study evidenced that mass spectroscopy is a useful technique not only for the identification but also for monitoring the spread of strains, which is critical to control nosocomial infections.

Screening and Scoring of Antimicrobial and Biological Activities of Italian Vulnerary Plants against Major Oral Pathogenic Bacteria

This study aims to evaluate the activity of Italian vulnerary plants against the most important oral pathogenic bacteria. This estimate was accomplished through a fivefold process: (a) a review of ethnobotanical and microbiological data concerning the Italian vulnerary plants; (b) the development of a scoring system to rank the plants; (c) the comparative assessment of microbiological properties; (d) the assessment of potential cytotoxic effects on keratinocyte-like cells and gingival fibroblasts in culture by XTT cell viability assay; (e) clinical evaluation of the most suitable plant extract as antibacterial agent in a home-made mouthwash. The study assays hexane (H), ethanol (E), and water (W) extracts from 72 plants. The agar diffusion method was used to evaluate the activity against Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Actinomyces viscosus. Twenty-two plants showed appreciable activity. The extracts showing the strongest antibacterial power were those from Cotinus coggygria Scop., Equisetum hyemale L., Helichrysum litoreum Guss, Juniperus communis L., and Phyllitis scolopendrium (L.) Newman subsp. scolopendrium. The potential cytotoxic effect of these extracts was assessed. On the basis of these observations, a mouth-rinse containing the ethanolic extract of H. litoreum has been tested in vivo, resulting in reduction of the salivary concentration of S. mutans.

Photodynamic and Antibiotic Therapy in Combination to Fight Biofilms and Resistant Surface Bacterial Infections.

Although photodynamic therapy (PDT), a therapeutic approach that involves a photosensitizer, light and O2, has been principally considered for the treatment of specific types of cancers, other applications exist, including the treatment of infections. Unfortunately, PDT does not always guarantee full success since it exerts lethal effects only in cells that have taken up a sufficient amount of photosensitizer and have been exposed to adequate light doses, conditions that are not always achieved. Based on our previous experience on the combination PDT/chemotherapy, we have explored the possibility of fighting bacteria that commonly crowd infected surfaces by combining PDT with an antibiotic, which normally does not harm the strain at low concentrations. To this purpose, we employed 5-aminolevulinic acid (5-ALA), a pro-drug that, once absorbed by proliferating bacteria, is converted into the natural photosensitizer Protoporphyrin IX (PpIX), followed by Gentamicin. Photoactivation generates reactive oxygen species (ROS) which damage or kill the cell, while Gentamicin, even at low doses, ends the work. Our experiments, in combination, have been highly successful against biofilms produced by several Gram positive bacteria (i.e., Staphylococcus aureus, Staphylococcus epidermidis, etc.). This original approach points to potentially new and wide applications in the therapy of infections of superficial wounds and sores.

Determination of the In Vitro and In Vivo Antimicrobial Activity on Salivary Streptococci and Lactobacilli and Chemical Characterisation of the Phenolic Content of a Plantago lanceolata Infusion

Introduction. Plant extracts may be suitable alternative treatments for caries. Aims. To investigate the in vitro and in vivo antimicrobial effects of Plantago lanceolata herbal tea (from flowers and leaves) on cariogenic bacteria and to identify the major constituents of P. lanceolata plant. Materials and Methods. The MIC and MBC against cariogenic bacteria were determined for P. lanceolata tea. Subsequently, a controlled random clinical study was conducted. Group A was instructed to rinse with a P. lanceolata mouth rinse, and Group B received a placebo mouth rinse for seven days. The salivary colonisation by streptococci and lactobacilli was investigated prior to treatment and on the fourth and seventh days. Finally, the P. lanceolata tea was analysed for its polyphenolic content, and major phenolics were identified. Results and Discussion. P. lanceolata teas demonstrate good in vitro antimicrobial activity. The in vivo test showed that Group A subjects presented a significant decrease in streptococci compared to Group B. The phytochemical analysis revealed that flavonoids, coumarins, lipids, cinnamic acids, lignans, and phenolic compounds are present in P. lanceolata infusions. Conclusions. P. lanceolata extract could represent a natural anticariogenic agent via an antimicrobial effect and might be useful as an ancillary measure to control the proliferation of cariogenic flora.

Clonal dissemination of Klebsiella pneumoniae ST512 carrying blaKPC‐3 in a hospital in southern Italy

Strains of Klebsiella pneumoniae producing KPC‐carbapenemase have emerged as one of the most important multidrug‐resistant Gram‐negative nosocomial pathogens. Here, we report the first isolation and subsequent dissemination of a K. pneumoniae ST512 producing KPC‐3 carbapenemase in a hospital in southern Italy. Isolates were obtained from blood, throat swabs, sputum, catheters, and urine of patients admitted to different hospital wards. Antimicrobial MICs were determined for all isolates by automated systems and confirmed by Etest. Carbapenemase production was confirmed by the modified Hodge test and by a disc synergy test, and carbapenemase genes were investigated by PCR. All isolates were characterized by pulse‐field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analysis. Most isolates were multidrug resistant with exception of some isolates intermediately susceptible to gentamicin, tigecycline, and trimethoprim‐sulfamethoxazole. PCR analysis showed that isolates harbored the blaKPC‐3 gene associated with blaTEM and blaSVH. PFGE and MLST showed that all isolates belonged to the same ST512 clone recently described in Israel.

Polyphenolic Profile and Targeted Bioactivity of Methanolic Extracts from Mediterranean Ethnomedicinal Plants on Human Cancer Cell Lines

The methanol extracts of the aerial part of four ethnomedicinal plants of Mediterranean region, two non-seed vascular plants, Equisetum hyemale L. and Phyllitis scolopendrium (L.) Newman, and two Spermatophyta, Juniperus communis L. (J. communis) and Cotinus coggygria Scop. (C. coggygria), were screened against four human cells lines (A549, MCF7, TK6 and U937). Only the extracts of J. communis and C. coggygria showed marked cytotoxic effects, affecting both cell morphology and growth. A dose-dependent effect of these two extracts was also observed on the cell cycle distribution. Incubation of all the cell lines in a medium containing J. communis extract determined a remarkable accumulation of cells in the G2/M phase, whereas the C. coggygria extract induced a significant increase in the percentage of G1 cells. The novelty of our findings stands on the observation that the two extracts, consistently, elicited coherent effects on the cell cycle in four cell lines, independently from their phenotype, as two of them have epithelial origin and grow adherent and two are lymphoblastoid and grow in suspension. Even the expression profiles of several proteins regulating cell cycle progression and cell death were affected by both extracts. LC-MS investigation of methanol extract of C. coggygria led to the identification of twelve flavonoids (compounds 1–11, 19) and eight polyphenols derivatives (12–18, 20), while in J. communis extract, eight flavonoids (21–28), a α-ionone glycoside (29) and a lignin (30) were found. Although many of these compounds have interesting individual biological activities, their natural blends seem to exert specific effects on the proliferation of cell lines either growing adherent or in suspension, suggesting potential use in fighting cancer.

Isolation of Enterobacter aerogenes carrying blaTEM‐1 and blaKPC‐3 genes recovered from a hospital Intensive Care Unit

Enterobacter aerogenes has recently emerged as an important hospital pathogen. In this study, we showed the emergence of E. aerogenes isolates carrying the blaKPC gene in patients colonized by carbapenem‐resistant Klebsiella pneumoniae strains. Two multiresistant E. aerogenes isolates were recovered from bronchial aspirates of two patients hospitalized in the Intensive Care Unit at the “Santa Maria della Scaletta” Hospital, Imola. The antimicrobial susceptibility test showed the high resistance to carbapenems and double‐disk synergy test confirmed the phenotype of KPC and AmpC production. Other investigation revealed that ESBL and blaKPC genes were carried on the conjugative pKpQIL plasmid. This is a relevant report in Italy that describes a nosocomial infection due to the production of KPC beta‐lactamases by an E. aerogenes isolate in patients previously colonized by K. pneumoniae carbapenem‐resistant. In conclusion, its necessary a continuous monitoring of multidrug‐resistant strains for the detection of any KPC‐producing bacteria that could expand the circulation of carbapenem‐resistant pathogens.

In vitro interaction of Stenotrophomonas maltophilia with human monocyte-derived dendritic cells

Stenotrophomonas maltophilia is increasingly identified as an opportunistic pathogen in immunocompromised, cancer and cystic fibrosis (CF) patients. Knowledge on innate immune responses to S. maltophilia and its potential modulation is poor. The present work investigated the ability of 12 clinical S. maltophilia strains (five from CF patients, seven from non-CF patients) and one environmental strain to survive inside human monocyte-derived dendritic cells (DCs). The effects of the bacteria on maturation of and cytokine secretion by DCs were also measured. S. maltophilia strains presented a high degree of heterogeneity in internalization and intracellular replication efficiencies as well as in the ability of S. maltophilia to interfere with normal DCs maturation. By contrast, all S. maltophilia strains were able to activate DCs, as measured by increase in the expression of surface maturation markers and proinflammatory cytokines secretion.