Maria Panopoulou

Can Procalcitonin in Cerebrospinal Fluid be a Diagnostic Tool for Meningitis

To study the levels of procalcitonin (PCT) in patients with meningitis and control group and compare them with established markers of infection—such as C‐reactive protein (CRP), high‐sensitivity CRP, and WBC—in cerebrospinal fluid (CSF) and assess the possible discriminative role of PCT in the differential diagnosis of meningitis from other noninfectious diseases.

Tissue and Swab Culture in Diabetic Foot Infections: Neuropathic Versus Neuroischemic Ulcers

We evaluated the diagnostic performance of swabs versus tissue cultures in 28 diabetic patients with neuropathic (group A) and 22 diabetic patients with neuroischemic foot ulcer (group B) and the differences in bacterial isolates between the 2 groups. In group A, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of swab cultures for the diagnosis of infection were 100%, 40%, 88.5%, and 100%, respectively. In group B, the corresponding values were 100%, 22.2%, 65%, and 100%. In group A, sensitivity, specificity, PPV, and NPV of swab cultures for the identification of pathogens were 100%, 14.3%, 53.8%, and 100%, respectively. In group B, the corresponding values were 100%, 18.2%, 55%, and 100%. In each group, Staphylococcus aureus and Pseudomonas aeruginosa were the most common isolates. The number of isolates was significantly higher on swab versus tissue cultures only in group A (P = .033). No differences were observed between groups in number of isolates and colony forming units. In conclusion, swab cultures are highly sensitive but less specific and have an excellent NPV both in diabetic patients with neuropathic and in those with neuroischemic foot ulcer. There are no differences between the groups in microbial load.

Immunomodulatory Role of Clarithromycin in Acinetobacter baumannii Infection via Formation of Neutrophil Extracellular Traps

ABSTRACT Macrolide antibiotics have been shown to act as immunomodulatory molecules in various immune cells. However, their effect on neutrophils has not been extensively investigated. In this study, we investigated the role of macrolide antibiotics in the generation of neutrophil extracellular traps (NETs). By assessing ex vivo and in vivo NET formation, we demonstrated that clarithromycin is able to induce NET generation both in vitro and in vivo. Clarithromycin utilizes autophagy in order to form NETs, and these NETs are decorated with antimicrobial peptide LL-37. Clarithromycin-induced NETs are able to inhibit Acinetobacter baumannii growth and biofilm formation in an LL-37-dependent manner. Additionally, LL-37 antimicrobial function depends on NET scaffold integrity. Collectively, these data expand the knowledge on the immunomodulatory role of macrolide antibiotics via the generation of LL-37-bearing NETs, which demonstrate LL-37-dependent antimicrobial activity and biofilm inhibition against A. baumannii.

Bacterial translocation in a rat model of large volume hepatic radiofrequency ablation.

BACKGROUND In this experimental study, we investigated the possibility of bacterial translocation, constituting a potential cause of infectious complications, after performing large volume hepatic radiofrequency ablation (RFA). MATERIALS AND METHODS Wistar rats were subjected to RFA of the left median liver lobe (approximately 28.5% of the liver volume) after midline laparotomy. At 30 min, 24 h, 48 h, 72 h or 1 wk postoperatively, (1) blood samples were collected from the portal and systemic circulation for assessment of endotoxin concentration, (2) tissue specimens were excised from mesenteric lymph nodes, non-ablated liver, pancreas, spleen, kidneys, and lungs for bacterial culture, and (3) segments of terminal ileum were excised for histopathologic examination, morphometric analysis, and apoptotic and mitotic rate estimation. At 1 and 48 h, ileal mucosa was collected for oxidative state assessment on the basis of glutathione to glutathione disulfate (GSH/GSSG) ratio. RESULTS Endotoxin levels were increased in both the portal and systemic circulation. Intestinal bacteria were isolated from all the organs at all time points. Ileal mucosa became gradually atrophic, with a decrease in villous height and density. There was an increase of crypt apoptotic rate, a decrease of GSH/GSSG ratio, while there were only mild signs of inflammation. CONCLUSIONS Large volume liver RFA in the rat resulted to endotoxemia and translocation of intestinal bacteria to proximal and distal to the intestine organs at both the early and late post-RFA periods. The intestinal mucosa barrier was disrupted as suggested by ileal mucosal atrophy, increased crypt apoptosis, and induction of oxidative stress.

Emergence of VIM-12 in Enterobacter cloacae

ABSTRACT Detection of the bla VIM-12 gene within the originally described Inh12 integron in a clinical isolate of Enterobacter cloacae is reported for the first time worldwide. Integron Inh12 was carried on a conjugative plasmid of approximately 85 kb which also conferred resistance to aztreonam, likely due to AmpC production.

Health costs from hospitalization with H1N1 infection during the 2009-2010 influenza pandemic compared with non-H1N1 respiratory infections.

Background The first positive patient with influenza A (H1N1) was recorded in March 2009 and the pandemic continued with new outbreaks throughout 2010. This study’s objective was to quantify the total cost of inpatient care and identify factors associated with the increased cost of the 2009–2010 influenza A pandemic in comparison with nonviral respiratory infection. Methods In total, 133 positive and 103 negative H1N1 patients were included from three tertiary care hospitals during the two waves of H1N1 in 2009 and 2010. The health costs for protective equipment and pharmaceuticals and hospitalization (medications, laboratory, and diagnostic tests) were compared between H1N1 positive and negative patients. Results The objective of the study was to quantify the means of daily and total costs of inpatient care. Overall, cost was higher for H1N1 positive (€61,0117.72) than for H1N1-negative patients (€464,923.59). This was mainly due to the protection measures used and the prolonged hospitalization in intensive care units. In H1N1-negative patients, main contributors to cost included additional diagnostic tests due to concern regarding respiratory capacity and laboratory values, as well as additional radiologic and microbial culture tests. The mean duration of hospitalization was 841 days for H1N1 positive and 829 days for negative patients. Conclusion Cost was higher in H1N1 patients, mainly due to the protection measures used and the increased duration of hospitalization in intensive care units. An automated system to monitor patients would be desirable to reduce cost in H1N1 influenza.

First report of Legionella pneumophila in car cabin air filters. Are these a potential exposure pathway for professional drivers

Abstract Recent findings have identified professional drivers as being at an increased risk of Legionnaires’ disease. Our hypothesis was that used car cabin air filters represent a reservoir of Legionella bacteria, and thus a potential pathway for contamination. We analysed used cabin air filters from various types of car. The filters were analysed by culture and by molecular methods. Our findings indicated that almost a third of air filters were colonized with Legionella pneumophila. Here, we present the first finding of Legionella spp. in used car cabin air filters. Further investigations are needed in order to confirm this exposure pathway. The presence of Legionella bacteria in used cabin air filters may have been an unknown source of infection until now.

Investigation of carbapenem heteroresistance among different sequence types of Pseudomonas aeruginosa clinical isolates reveals further diversity

Pseudomonas aeruginosa is a leading infectious agent causing difficult-to-treat nosocomial infections due to the multiresistant phenotype that it often exhibits. Expression of the intrinsic AmpC b-lactamase, overexpression of Mex–Opr-type efflux pumps as well as repression of porin OprD have been associated with b-lactam resistance in this species (Lister et al., 2009). Also, different genotypes of carbapenem-susceptible P. aeruginosa have been documented to produce carbapenem-heteroresistant subpopulations (Pournaras et al., 2007).

Accumulation of multiple mutations in linezolid-resistant Staphylococcus epidermidis causing bloodstream infections; in silico analysis of L3 amino acid substitutions that might confer high-level linezolid resistance.

Fifty-six Staphylococcus epidermidis clinical isolates, showing high-level linezolid resistance and causing bacteremia in critically ill patients, were studied. All isolates belonged to ST22 clone and carried the T2504A and C2534T mutations in gene coding for 23SrRNA as well as the C189A, G208A, C209T and G384C missense mutations in L3 protein which resulted in Asp159Tyr, Gly152Asp and Leu94Val substitutions. Other silent mutations were also detected in genes coding for ribosomal proteins L3 and L22. In silico analysis of missense mutations showed that although L3 protein retained the sequence of secondary motifs, the tertiary structure was influenced. The observed alteration in L3 protein folding provides an indication on the putative role of L3-coding gene mutations in high-level linezolid resistance. Furthermore, linezolid pressure in health care settings where linezolid consumption is of high rates might lead to the selection of resistant mutants possessing L3 mutations that might confer high-level linezolid resistance.

Molecular characterization of Streptococcus agalactiae from vaginal colonization and neonatal infections: a 4-year multicenter study in Greece☆

A multicenter collection comprising of 171 Streptococcus agalactiae isolates from pregnant women recovered between 2007 and 2010 and 46 from unmatched neonates with invasive infections was subjected to antimicrobial susceptibility testing and genetic characterization. High rates of erythromycin resistance (20.47%) were observed only in isolates from pregnant women. ST1 was dominant in the vaginal colonization, whereas the hypervirulent ST-17 clone was detected in 67.39% of neonatal infections.