[Isolated bacteria from nasal cultures. Are they important in patients with acute leukemia?]

The nasal colonization by Staphylococcal (epidermidis or aureus) is frequent and it has importance when it is associated to bacteremia in immunocompromised patients. The objective was to determine the frequency of strains that colonize the nasal mucosa in patients with leukemia and its relationship with peripheral blood cultures.

A retrospective, observational, transversal, retrolective study was done. We analyzed the weekly results of nasal cultures and peripheral blood cultures in patients with leukemia undergoing chemotherapy. The chi-squared test and odds ratio value were estimated in the statistical analysis.

We included 67 patients, 55 of them with acute lymphocytic leukemia (ALL); 28.5 % of the cultures (n = 47) corresponded to a positive nasal culture. Staphylococcus epidermidis and Staphylococcus aureus were the most isolated bacteria. During the first week of treatment, the positive cultures were the most frequently. All the samples isolated were sensitive to vancomycin or linezolid. It was established only the association between negative nasal cultures and negative peripheral blood cultures (p = 0.0005). Odds ratio for positive nasal cultures and the risk of bacteremia was 0.0269.

The frequency of the positive bacteria culture was low, with an adequate sensitivity measure. The presence of bacteria in nasal culture was not identified as a risk factor for the occurrence of bacteremia.