Arne N. Eskesen

Genotyping of 353 Staphylococcus aureus Bloodstream Isolates Collected between 2004 and 2009 at a Norwegian University Hospital and Potential Associations with Clinical Parameters

ABSTRACT We analyzed 353 Staphylococcus aureus bloodstream isolates from 2004 to 2009 to identify dominant genotypes, changes over time, and associations between genotype, phenotype, and clinical parameters. The isolates were genotyped with regard to spa type and presence of Panton-Valentine leukocidin and toxic shock syndrome toxin 1-encoding genes. A high level of genetic diversity was detected. All but three isolates were methicillin sensitive. Interestingly, spa clonal complex 021 showed a weak association with higher all-cause hospital mortality.

Genetic variants at the ITPA locus protect against ribavirin-induced hemolytic anemia and dose reduction in an HCV G2/G3 cohort.

Objectives Two functional genetic variants in the inosine triphosphatase (ITPA) gene have been shown to be strongly associated with protection from ribavirin (RBV)-induced hemolysis. We aimed at evaluating this finding in a chronic hepatitis C genotype 2/3 cohort with a predominance of genotype 3 patients where available data are scarce. A second objective was to determine whether a protective association translated into the need for RBV reduction and hence a possible impact on treatment response. Methods Overall, 457 patients were recruited from two trials of genotype 2/3 patients treated with pegylated interferon &agr;-2b and weight-based RBV. rs1127354 and rs7270101 were genotyped and a composite ITPAase deficiency variable was graded according to the two single nucleotide polymorphisms. The primary endpoints were hemoglobin (Hb) decline from baseline and Hb decline of more than 3 g/dl at week 4. Results Both single nucleotide polymorphisms and the composite ITPAase deficiency variable were strongly and independently associated with protection from a decline in Hb at week 4 in multivariate linear regression models (Prs1127354=7.0×10−4, Prs7270101=0.0036, PITPase deficiency variable =6.3×10−22). Patients with any degree of reduced ITPAase activity were less likely to have their RBV dose reduced (odds ratio 0.39, 95% confidence interval 0.16–0.96, P=0.040), although this did not translate into increased rapid viral response or sustained viral response (Prvr=0.93, Psvr=0.22). Conclusion We have confirmed a strong association between functional ITPA variants and RBV-induced hemolysis and showed protection from RBV dose reduction, although this did not translate into increased rapid viral response or sustained viral response.

Molecular Characterization of Methicillin-Sensitive Staphylococcus aureus Isolates from Bacteremic Patients in a Norwegian University Hospital

ABSTRACT Staphylococcus aureus bacteremia is common in both nosocomial and community settings, and the pathogenicity of the microbe depends upon a large repertoire of virulence factors. S. aureus bacteremia isolates (n = 126) were characterized using DNA microarrays. Clonal complexes 5, 8, 15, 30, and 45 accounted for 74.6% of the isolates. We identified geographical differences in dominating clones and toxin gene profiles. One isolate was methicillin resistant. Potential associations between age and genotype were detected.

Short-term success, but long-term treatment failure with linezolid for enterococcal endocarditis.

We report a case of linezolid treatment failure for Enterococcus faecalis endocarditis. Despite success during and shortly after treatment, the patient had a relapse after 7 weeks. Due to prior anaphylactic reaction to penicillin, desensitization was performed, and successful penicillin therapy given. The efficacy of linezolid for enterococcal endocarditis remains questionable.

Infectious tenosynovitis and osteomyelitis caused by Mycobacterium nonchromogenicum

Infections due to Mycobacterium terrae complex are rare. We report a severe case of chronic tenosynovitis and osteomyelitis of the hand caused by Mycobacterium nonchromogenicum requiring second ray finger amputation.

Anisakiasis Presenting as an Obstructive Duodenal Tumor. A Scandinavian Case

A case of chronic anisakiasis presenting as an occluding duodenal tumor is described. Significant falls in Anisakis simplex-specific serum IgE and total IgE occurred after resection of the lesion. Histopathologic examination showed a chronic eosinophilic granulomatous infiltrate and a tubular sclerotic structure in the antral submucosa consistent with, but not diagnostic for, an A. simplex larva.A case of chronic anisakiasis presenting as an occluding duodenal tumor is described. Significant falls in Anisakis simplex-specific serum IgE and total IgE occurred after resection of the lesion. Histopathologic examination showed a chronic eosinophilic granulomatous infiltrate and a tubular sclerotic structure in the antral submucosa consistent with, but not diagnostic for, an A. simplex larva.

DNA microarray analysis of Staphylococcus aureus causing bloodstream infection: bacterial genes associated with mortality?

Providing evidence for microbial genetic determinants’ impact on outcome in Staphylococcus aureus bloodstream infections (SABSI) is challenging due to the complex and dynamic microbe–host interaction. Our recent population-based prospective study reported an association between the S. aureus clonal complex (CC) 30 genotype and mortality in SABSI patients. This follow-up investigation aimed to examine the genetic profiles of the SABSI isolates and test the hypothesis that specific genetic characteristics in S. aureus are associated with mortality. SABSI isolates (n = 305) and S. aureus CC30 isolates from asymptomatic nasal carriers (n = 38) were characterised by DNA microarray analysis and spa typing. Fisher’s exact test, least absolute shrinkage and selection operator (LASSO) and elastic net regressions were performed to discern within four groups defined by patient outcome and characteristics. No specific S. aureus genetic determinants were found to be associated with mortality in SABSI patients. By applying LASSO and elastic net regressions, we found evidence suggesting that agrIII and cna were positively and setC (=selX) and seh were negatively associated with S. aureus CC30 versus non-CC30 isolates. The genes chp and sak, encoding immune evasion molecules, were found in higher frequencies in CC30 SABSI isolates compared to CC30 carrier isolates, indicating a higher virulence potential. In conclusion, no specific S. aureus genes were found to be associated with mortality by DNA microarray analysis and state-of-the-art statistical analyses. The next natural step is to test the hypothesis in larger samples with higher resolution methods, like whole genome sequencing.

Predictors of one-year all-cause mortality and infection-related mortality in patients with Staphylococcus aureus bacteraemia

Abstract Objectives: Staphylococcus aureus bacteraemia (SAB) is a common infection associated with significant short-term mortality. Little is known about long-term prognosis. The aim of this study was to determine one-year all-cause mortality and infection-related mortality and associated predictors. Methods: Data from 303 consecutive patients with SAB were prospectively collected from March 2011 to February 2014. All patients were followed one year or until death. Results: One-year all-cause- and infection-related mortality were 36.7% and 20.8%, respectively. For all-cause mortality, in multivariable logistic regression analysis, age 70–79 years (OR 3.9; 95% CI 1.7–9.1; p = .001), Charlson Comorbidity index ≥3 (OR 6.9; 95% CI 2.7–17.3; p < .001), healthcare-associated infection (OR 2.3; 95% CI 1.1–4.9; p = .03) and severe sepsis (OR 3.6; 95% CI 1.8–7.1; p < .001) were independent predictors of outcome. For infection-related mortality, the predictors were similar, except for healthcare-associated infection that lost significance. The vast majority (89%) of infection-related deaths occurred within 30 days. Conclusions: This study demonstrates additional significant all-cause mortality in patients with SAB beyond 30 days to one year, mainly driven by high age and comorbidity. As a result, SAB can be considered an indirect marker of high risk of death in these patients. Follow-up beyond 30 days does not add significant information with respect to infection-related mortality.

Correction for Blomfeldt et al., Molecular Characterization of Methicillin-Sensitive Staphylococcus aureus Isolates from Bacteremic Patients in a Norwegian University Hospital

Volume 51, no. 1, p. [345–347][1], 2013. Page 346, [Table 1][2]: Owing to misclassification of infections as hospital acquired (HA) or community acquired (CA), some entries in the third and fourth columns were wrong. The conclusions of the paper are unchanged, as the misclassifications went in

Correction for Aamot et al., Genotyping of 353 Staphylococcus aureus Bloodstream Isolates Collected between 2004 and 2009 at a Norwegian University Hospital and Potential Associations with Clinical Parameters

Volume 50, no. 9, p. [3111–3114][1], 2012. Page 3112, [Table 1][2]: For the sixth entry in the “CC” section of the first column, “ spa C304/024” should read “ spa CC304/024,” and owing to misclassification of infections as hospital acquired (HA) or community acquired (CA), several