Escherichia coli strains of chicken and human origin: Characterization of antibiotic and heavy-metal resistance profiles, phylogenetic grouping, and presence of virulence genetic markers.

Multiple antibiotic-resistant extra-intestinal pathogenic Escherichia coli (ExPEC) strains represent a serious health care problem both for poultry and humans. Recently isolates with combined resistance to both antibiotics and heavy metals have been increased worldwide, with growing concern for possible co-selection of antimicrobial resistant genes. In the present study we characterized, at a phenotypic and genetic level, 80 E. coli isolates: forty independent isolates were collected from manure samples of healthy chickens and 40 from independent human extra-intestinal infections (ExPEC strains). The results obtained indicated that i) compared to chicken, human isolates presented a broader spectrum of antibiotic resistance and virulence potentials; ii) although at a lower extent, ExPEC-associated virulence genes were also present in chicken isolates, suggesting they may be potentially pathogens; iii) that arsenic (As) and zinc (Zn) tolerance genetic determinants were significantly more prevalent among chicken and human isolates respectively, while those responsible for tolerance to cadmium (Cd), silver (Ag) and copper (Cu) were equally distributed among the two groups of strains; iv) a very strong correlation was found between chicken gentamicin (GM) resistance and cadmium (Cd) tolerance. Elucidating the role of heavy metals in the selection and spread of highly pathogenic E. coli strains (co-selection) is of primary importance to lower the potential risk of infections in poultry and humans. The control of bacterial zoonotic agents, that commonly occur in livestock and that may be transmitted, directly or via the food chain, to human populations, could be of relevant interest.

Satureja montana L. Essential Oils: Chemical Profiles/Phytochemical Screening, Antimicrobial Activity and O/W NanoEmulsion Formulations.

Chemical fingerprints of four different Satureja montana L. essential oils (SEOs) were assayed by an untargeted metabolomics approach based on Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) coupled with either electrospray ionization or atmospheric pressure chemical ionization ion sources. Analysis and relative quantification of the non-polar volatile fraction were conducted by gas chromatography (GC) coupled to MS. FT-ICR MS confirmed significant differences in the polar metabolite composition, while GC-MS analyses confirmed slight fluctuations in the relative amount of major terpenes and terpenoids, known to play a key role in antimicrobial mechanisms. Oil in eater (O/W) nanoemulsions (NEs) composed by SEOs and Tween 20 or Tween 80 were prepared and analyzed in terms of hydrodynamic diameter, ζ-potential and polydispersity index. The results confirm the formation of stable NEs homogeneous in size. Minimum inhibitory and minimum bactericidal concentrations of SEOs were determined towards Gram-positive (Listeria monocytogenes, Staphylococcus aureus, Staphylococcus haemolyticus) and Gram-negative clinical isolates (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens). Commercial SEO showed strongest antibacterial activity, while SEO 3 was found to be the most active among the lab made extractions. MIC and MBC values ranged from 0.39 to 6.25 mg·mL-1. Furthermore, a SEO structured in NEs formulation was able to preserve and improve antimicrobial activity.

Satureja montana L. essential oil and its antimicrobial activity alone or in combination with gentamicin.

Many essential oils (EOs) are screened as potential sources of antimicrobial compounds. EOs from the genus Satureja have recognized biological properties, including analgesic, anti-inflammatory, immunomodulatory, anticancer, and antimicrobial activity. This study aimed to obtain a metabolite profile of commercial essential oil of S. montana L. (SEO) and to evaluate its antimicrobial properties, both alone and combined with gentamicin towards Gram-negative and Gram-positive bacterial strains. Untargeted analyses based on direct infusion Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and on GC-MS have provided a high metabolome coverage, allowing to identify carvacrol, cymene and thymol as the major components of commercial SEO. SEO exerted an antimicrobial activity and induced a synergistic interaction with gentamicin against both reference and clinical bacterial strains. A significant reduction of Escherichia coli, Staphylococcus aureus and Listeria monocytogenes biofilm formation was induced by SEO. As a result of SEO treatment, clear morphological bacterial alterations were visualized by scanning electron microscopy: L. monocytogenes and S. aureus showed malformed cell surface or broken cells with pores formation, whereas E. coli displayed collapsed cell surface. These results encourage further studies about bactericidal and antibiotic synergistic effect of SEO for combined therapy in clinical setting as well as in agricultural systems.

Virulence behavior of uropathogenic Escherichia coli strains in the host model Caenorhabditis elegans.

Urinary tract infections (UTIs) are among the most common bacterial infections in humans. Although a number of bacteria can cause UTIs, most cases are due to infection by uropathogenic Escherichia coli (UPEC). UPEC are a genetically heterogeneous group that exhibit several virulence factors associated with colonization and persistence of bacteria in the urinary tract. Caenorhabditis elegans is a tiny, free-living nematode found worldwide. Because many biological pathways are conserved in C. elegans and humans, the nematode has been increasingly used as a model organism to study virulence mechanisms of microbial infections and innate immunity. The virulence of UPEC strains, characterized for antimicrobial resistance, pathogenicity-related genes associated with virulence and phylogenetic group belonging was evaluated by measuring the survival of C. elegans exposed to pure cultures of these strains. Our results showed that urinary strains can kill the nematode and that the clinical isolate ECP110 was able to efficiently colonize the gut and to inhibit the host oxidative response to infection. Our data support that C. elegans, a free-living nematode found worldwide, could serve as an in vivo model to distinguish, among uropathogenic E. coli, different virulence behavior.

Bacterial biofilm associated with a case of capsular contracture.

Capsular contracture is one of the most common complications of implant-based breast augmentation. Despite its prevalence, the etiology of capsular contracture remains controversial although the surface texture of the breast implant, the anatomical position of the prosthesis and the presence of bacterial biofilm could be considered trigger factors. In fact, all medical implants are susceptible to bacterial colonization and biofilm formation. The present study demonstrated the presence of microbial biofilm constituted by cocci in a breast implant obtained from a patient with Baker grade II capsular contracture. This suggests that subclinical infection can be present and involved in low grade capsular contracture.

Coriander (Coriandrum sativum) Essential Oil: Effect on Multidrug Resistant Uropathogenic Escherichia coli.

Coriander (Coriandruim sativum L., Apiaceae) is known for its antimicrobial activity and the aim of this study was to investigate the effect of its essential oil (CDO) against multidrug resistant uropathogenic Escherichia coli (UPEC). CDO was able to inhibit the growth of UPEC strains and propidium iodide uptake, - and electron microscopy examination suggested that bacterial structural modifications occurred. The presence of CDO reduced the MIC of gentamicin. E.coli adhesion efficiency on cell monolayers and abiotic surfaces was not affected by subMIC oil concentrations; furthermore, CDO showed cytotoxic activity towards the HEp-2 tumor cell line. These findings contribute to the knowledge about essential oils as sources of potential antimicrobial agents against uropathogenic E. coli and encourage further investigations.

Diagnostic accuracy of Xpert MTB/RIF versus smear microscopy in the early diagnosis tuberculosis in the real life of "Umberto I" Hospital Rome.

Early diagnosis of tuberculosis (TB) is one of the primary challenges in curtailing the spread of TB. This study aimed to determine the diagnostic accuracy of Xpert MTB/RIF for the identification of M. tuberculosis in clinical specimens, and compare this to a microscopist's diagnostic performance. Xpert MTB/ RIF was positive in all specimens with culture-confirmed TB, giving a higher sensitivity than the smear microscopy (100% versus 63%). The use of the Xpert MTB/RIF, as part of routine assay, permits rapid diagnosis of TB and enables clinicians to start an effective treatment.

Features of uropathogenic Escherichia coli able to invade a prostate cell line.

RWPE-1 normal prostate cells were tested as an experimental model for adhesion/invasion assays by genotypically and phenotypically characterized community uropathogenic strains of Escherichia coli (UPEC), a frequent cause of urinary tract infections (UTIs) and significant etiologic agent also in bacterial prostatitis. Adhesive ability and strong biofilm production was significantly associated with the bacterial invasive phenotype. Invasive strains derived mainly from male and pediatric patients. This study suggests that such a cell model could usefully integrate other available methods of urovirulence analysis, to deepen knowledge on the bacterial interaction with host cells.

Risk Factors and Outcomes for Bloodstream Infections Secondary to Clostridium difficile Infection.

We determined the incidence, risk factors, and outcomes of bloodstream infections (BSI) subsequent to Clostridium difficile infection (CDI). We performed a retrospective study of all patients with definite diagnosis of CDI admitted from January 2014 to December 2014 in two large hospitals in Rome. Two groups of patients were analyzed: those with CDI and subsequent BSI (CDI/BSI(+)) and those with CDI and no evidence of primary BSI (CDI/BSI(-)). Data about clinical features, microbiology, treatments, and mortality were obtained. Overall, 393 cases of CDI were included in the final analysis: 72 developed a primary nosocomial BSI, while 321 had CDI without microbiological and clinical evidence of BSI. Etiologic agents of BSI were Candida species (47.3%), Enterobacteriaceae (19.4%), enterococci (13.9%), and mixed infections (19.4%). In multivariate analysis, ribotype 027 status (odds ratio [OR], 6.5), CDI recurrence (OR, 5.5), severe CDI infection (OR, 8.3), and oral vancomycin at >500 mg/day (OR, 3.1) were recognized as factors independently associated with the development of nosocomial BSI. Thirty-day mortality from CDI diagnosis was higher for patients of the CDI/BSI(+) group than for the controls (38.9 versus 13.1%; P < 0.001). Among patients of the CDI/BSI(+) group, mortality attributable to primary BSI was as high as 57%. Our findings suggest that severe CDI is complicated by the development of nosocomial BSI. Candida species and enteric bacteria appear to be the leading causative pathogens and are associated with poor outcomes.

Influenza A virus infection of intestinal epithelial cells enhances the adhesion ability of Crohn's disease associated Escherichia coli strains.

Modifications of intestinal glycoreceptors expression, in particular CEACAM6, typically found in ileal Crohn's disease (CD), favor, among the commensal species of microbiota, the enrichment in Escherichia coli. Removal of protein glycosidic residues by neuraminidase, a sialidase typical of influenza virus, increases adhesion ability of Escherichia coli to Caco-2 intestinal cells. In this study we investigated whether influenza virus infection of human intestinal epithelial cells could influence the adhesiveness of different Escherichia coli strains isolated from CD patients by altering surface glycoreceptors. Influenza virus infection of intestinal cells increased exposure of galactose and mannose residues on the cell surface. In particular, glycoreceptors Thomsen-Friedenreich and CEACAM6 were over-expressed in influenza virus infected cells. In the same experimental conditions, a significant increase in bacterial adhesiveness was observed, independently of their own adhesive ability. The increase was reverted by treatment with anti-TF and anti-CEACAM6 antibodies. Interestingly, influenza virus was able to efficiently replicate in human primary intestinal cells leading to TF exposure. Finally, intestinal infected cells produced high levels of pro-inflammatory cytokines compared to control. Overall these data suggest that influenza virus infection, could constitute an additional risk factor in CD patients.

Linezolid-resistant staphylococcal bacteraemia: A multicentre case-case-control study in Italy.

The aim of this multicentre study was to analyse the characteristics of patients with bloodstream infections due to staphylococcal strains resistant to linezolid. This was a retrospective case-case-control study of patients hospitalised in three large teaching hospitals in Italy. A linezolid-resistant (LIN-R) Staphylococcus spp. group and a linezolid-susceptible (LIN-S) Staphylococcus spp. group were compared with control patients to determine the clinical features and factors associated with isolation of LIN-R strains. All LIN-R Staphylococcus spp. strains underwent molecular typing. Compared with the LIN-S group, central venous catheters were the main source of infection in the LIN-R group. The LIN-R and LIN-S groups showed a similar incidence of severe sepsis or septic shock, and both showed a higher incidence of these compared with the control group. Overall, patients in the LIN-R group had a higher 30-day mortality rate. Multivariate analysis found previous linezolid therapy, linezolid therapy >14 days, antibiotic therapy in the previous 30 days, antibiotic therapy >14 days, previous use of at least two antibiotics and hospitalisation in the previous 90 days as independent risk factors associated with isolation of a LIN-R strain. The G2576T mutation in domain V of 23S rRNA was the principal mechanism of resistance; only one strain of Staphylococcus epidermidis carried the cfr methylase gene (A2503), together with L4 insertion (71GGR72) and L3 substitution (H146Q). LIN-R strains are associated with severe impairment of clinical conditions and unfavourable patient outcomes. Reinforcement of infection control measures may have an important role in preventing these infections.

Streptococcus anginosus group disseminated infection: case report and review of literature.

Streptococcus anginosus group is widely known for its ability to cause invasive pyogenic infections. There are very few reports of disseminated infections sustained by members of this streptococcal group. We report a case of a highly disseminated infection and analyse previous literature reports. Disseminated pyogenic infection has been defined as an infection affecting two or more of the following organs/systems: central nervous system, lung, liver and spleen. We performed a PubMed search using the terms: S. milleri, S. anginosus, brain abscess, pulmonary abscess, hepatic abscess, spleen abscess. We reviewed 12 case reports including the one presented in this paper. Underlying conditions such as dental infections, malignancy, gastrointestinal and respiratory tract disease accounted for 42% of cases. No definite endocarditis was encountered, even though positive blood cultures were found in 67% of patients. Concomitant brain-liver, brain-lung and brain-spleen involvement occurred in 50%, 42% and 8% of cases respectively. Ninety-one percent (91%) of patients were treated with ß-lactams, and surgical procedures were performed in 67% of patients. Infections caused by S. anginosus group members are satisfactorily treated with penicillin G and cephalosporins. It is very important to associate surgery to antimicrobial chemotherapy in order to achieve a full or nearly full clinical recovery.

Synthesis and anti-rhinovirus properties of fluoro-substituted flavonoids.

Fluoro-substituted flavones and 2-styrylchromones, related to natural and synthetic flavonoids previously described, were prepared, characterized and tested for anti-rhinovirus activity. Structural elucidation of the new compounds was performed by IR, NMR spectra and X-ray crystal structure analysis for 6-fluoro-3-hydroxy-2-styrylchromone. The antiviral potency was evaluated by a plaque reduction assay in HeLa cell cultures infected with rhinoviruses 1B and 14, selected as representative serotypes for viral groups B and A of human rhinoviruses, respectively. In comparison with results previously obtained, the introduction of the fluorine atom seems to exert a positive influence on the activity against serotype 14 while counteracting the effect against serotype 1B.