Domenico D'Antonio

Factors associated with adherence to and biofilm formation on polystyrene by Stenotrophomonas maltophilia: the role of cell surface hydrophobicity and motility

We tested 40 clinical Stenotrophomonas maltophilia strains to investigate the possible correlation between adherence to and formation of biofilm on polystyrene, and cell surface properties such as hydrophobicity and motility. Most of the strains were able to adhere and form biofilm, although striking differences were observed. Eleven (27.5%) of the strains were hydrophobic, with hydrophobicity greatly increasing as S. maltophilia attached to the substratum. A positive correlation was observed between hydrophobicity and levels of both adhesion and biofilm formation. Most of the isolates showed swimming and twitching motility. A highly significant negative correlation was observed between swimming motility and level of hydrophobicity. Hydrophobicity is thus a significant determinant of adhesion and biofilm formation on polystyrene surfaces in S. maltophilia.

Drug sensitivity and clinical impact of members of the genus Kocuria.

Organisms in the genus Kocuria are Gram-positive, coagulase-negative, coccoid actinobacteria belonging to the family Micrococcaceae, suborder Micrococcineae, order Actinomycetales. Sporadic reports in the literature have dealt with infections by Kocuria species, mostly in compromised hosts with serious underlying conditions. Nonetheless, the number of infectious processes caused by such bacteria may be higher than currently believed, given that misidentification by phenotypic assays has presumably affected estimates of the prevalence over the years. As a further cause for concern, guidelines for therapy of illnesses involving Kocuria species are lacking, mostly due to the absence of established criteria for evaluating Kocuria replication or growth inhibition in the presence of antibiotics. Therefore, breakpoints for staphylococci have been widely used throughout the literature to try to understand this pathogens behaviour under drug exposure; unfortunately, this has sometimes created confusion, thus higlighting the urgent need for specific interpretive criteria, along with a deeper investigation into the resistance determinants within this genus. We therefore review the published data on cultural, genotypic and clinical aspects of the genus Kocuria, aiming to shed some light on these emerging nosocomial pathogens.

Catheter-Related Candidemia Caused by Candida lipolytica in a Patient Receiving Allogeneic Bone Marrow Transplantation

ABSTRACT Candida lipolytica was recovered from the blood and the central venous catheter in a patient receiving allogeneic bone marrow transplantation. Two C. lipolytica strains from different geographical areas and the ATCC 9773 strain of C. lipolytica were used as controls. C. lipolytica was identified by standard methods. MICs indicated antifungal susceptibilities to amphotericin B, fluconazole, and itraconazole for all strains. In vitro testing and scanning electron microscopy showed that C. lipolytica was capable of producing large amounts of viscid slime material in glucose-containing solution, likely responsible for the ability of the yeast to adhere to catheter surfaces. Restriction fragment length polymorphisms revealed an identical profile for all clinical isolates, unrelated to those observed for the control strains. This finding suggested the absence of microevolutionary changes in the population of the infecting strain, despite the length of the sepsis and the potential selective pressure of amphotericin B, which had been administered to the patient for about 20 days. The genomic differences that emerged between the isolates and the control strains were indicative of a certain degree of genetic diversity between C. lipolytica isolates from different geographical areas.

Femoral Prosthesis Infection by Rhodotorula mucilaginosa

ABSTRACT This case report is a case history of a femoral prosthesis infection caused by Rhodotorula mucilaginosa in a human immunodeficiency virus patient. Though the pathogenicity of this organism for bone tissue has been previously reported, this is the first reported case of an orthopedic prosthesis infection by this species of the genus Rhodotorula.

Multidrug-Resistant Escherichia fergusonii: a Case of Acute Cystitis

ABSTRACT We report a case in which Escherichia fergusonii, an emerging pathogen in various types of infections, was associated with cystitis in a 52-year-old woman. The offending strain was found to be multidrug resistant. Despite in vitro activity, beta-lactam treatment failed because of a lack of patient compliance with therapy. The work confirms the pathogenic potential of E. fergusonii.

Preliminary evaluation of the safety and efficacy of standard intravenous immunoglobulins in pregnant women with primary cytomegalovirus infection.

ABSTRACT Hyperimmune globulins were reported to prevent and treat fetal cytomegalovirus (CMV) infection during pregnancy. Here, we report that infusions of standard human intravenous immunoglobulin significantly increase CMV IgG titers and avidity indexes in pregnant women, paving the way to their use for passive transfer of maternal CMV humoral immunity to fetuses. Preliminary data on perinatal outcomes of the first 67 newborns are encouraging.

Epidemiology, Pathogenicity and Emerging Resistances in Staphylococcus pasteuri: From Mammals and Lampreys, to Man

Staphylococcus pasteuri is a coagulase-negative, Gram positive organism which is emerging as an agent of nosocomial infections and a blood derivatives contaminant, though its role in causing human disease mostly remains controversial. Despite the paucity of isolates recovered, this bacterium has recently appeared to express resistance against several classes of antibiotic compounds, such as methicillin/oxacillin, macrolides, lincosamides, streptogramins, tetracyclines, chloramphenicol, streptomycin, fosfomycin, as well as quaternary ammonium compounds. Also, authors will discuss some essential patents related to the topic reviewed.

Bacterial Contamination of Platelets and Septic Transfusions: Review of the Literature and Discussion on Recent Patents About Biofilm Treatment

In spite of the improvements in transfusion safety occurred in the last decades, platelet septic transfusions still represent a cause for concern. Microbial screening of blood products cannot ensure transfusion sterility, so that pathogen inactivation methods and a timely management of infectious events actually play the most relevant role. Biofilm production has been associated to several human illnesses; also, it promotes bacterial adherence to platelet bags and colonization of recipients catheter after transfusion. Therefore, facing biofilm communities is required to reduce the contamination risk and the occurrence of post-infusion events. In this context, the use of tigecycline as a wide-spectrum antibiofilm drug is discussed, along with recent patents about biofilm treatment by quorum-sensing blockers, bacteriophage-based therapy and antibiofilm oral compounds.

β-Lactam Failure in Treatment of Two Group G Streptococcus dysgalactiae subsp. equisimilis Pharyngitis Patients

ABSTRACT We present two cases of exudative pharyngitis due to Streptococcus dysgalactiae subsp. equisimilis, Lancefield group G. While the participation of this organism as an agent of pharyngitis is well documented, we focus on failure of beta-lactam therapy, a phenomenon that is well described for pharyngitis due to Streptococcus pyogenes. Therefore, these case reports add to our knowledge of pharyngitis caused by non-S. pyogenes streptococci.

Comparison between the BACTEC 9240 and the Pall eBDS system for detection of bacterial platelet concentrate contamination

BACKGROUND: Only two commercially available automated systems have been cleared by the FDA for screening of bacterial contamination in platelet (PLT) products. These are the Pall eBDS (Pall Corp.), based on measurement of oxygen consumption by contaminant organisms, and the BacT/ALERT (bioMérieux), revealing increasing carbon dioxide concentration due to bacterial growth.