The aim of this study was to compare the in vitro activity of ethanol, EDTA and levofloxacin (Levo), alone or in combination, on biofilms of Stenotrophomonas maltophilia recovered from patients with catheter-related bloodstream infections (CRBSIs) at a university hospital in Argentina. First, 24 and 48 h biofilms were formed in microtitre plates and challenged with 25 or 40 % ethanol for 1 h. Biofilms, of the 14 local isolates and from the reference strain K279a, were eradicated after both treatments as shown by plate counts and the regrowth technique. Second, 24 h biofilms of all isolates were established in silicone catheter segments and challenged with 25 or 40 % ethanol, Levo (2.5 mg ml ), 25 % ethanol-EDTA or Levo-EDTA for 1, 3 and 24 h. Viable counts of biofilms treated for 1 h with 25 or 40 % ethanol or 25 % ethanol-EDTA were under the limit of detection. Killing of biofilms by Levo or Levo-EDTA was gradual and it was only after 24 h of treatment that no differences could be seen between the effects of these catheter lock solutions (CLSs) and those of ethanol (P.0.05). Levo-EDTA, in combination, did not act synergistically against biofilms. After 24 h of exposure, EDTA did not eradicate biofilms but reduced biofilm survival rates to 1-5 %. The effect of the different CLSs on biomass reduction, estimated by crystal violet staining, was highly dependent on the isolate, and the most effective agents were 25 and 40 % ethanol. Our results suggest that when used as a CLS for short periods, ethanol at low concentrations, alone or in combination with a chelator, can decontaminate the line from S. maltophilia in cases of CRBSI and help, in conjunction with systemic antibiotics, in the retention of precious vascular catheters.

Mannose-binding lectin (MBL) plays an important role in the innate immune defense against invading microorganisms. Deficiency of functional MBL is linked to polymorphisms in the MBL2 gene. The aim of the study was to determine the influence of MBL2 polymorphisms in susceptibility to HTLV-1 infection. A total of 43 HTLV-1 infected subjects and 127 healthy controls were evaluated for polymorphisms in the coding region of MBL2 gene. The point mutations in exon 1 at codon 54 (allele B) and codon 52 (allele D) and the wild type allele A were detected by PCR-RFLP. The frequency of the allele A, B and D was 66%, 29% and 5% among HTLV-1 infected subjects and 79%, 18% and 3% among healthy controls, respectively. Genotype and allele frequencies were statistically different between both groups, being the allele B more frequent among HTLV-1 infected subjects than in controls (29% and 18%, respectively; p=0.032). Moreover, the homozygous genotype BB was observed in 14% of HTLV-1 patients and only 3% of controls (p=0.016), and it was associated with an almost five-fold higher risk of OR=4.98, 95%CI=1,63). Our results suggest that carriers of the MBL2 allele B are more susceptible to HTLV-1 infection. Further studies with a large number of individuals are ongoing to confirm the impact of MBL polymorphisms as genetic determinant of HTLV-1 susceptibility.

Mangano et al.: HTLV-1 proviral load in adult T-cell leukemia/lymphoma (ATLL) patients from non-endemic regions of Argentina. Retrovirology 2014 11(Suppl 1):P34.