Risk factors for bloodstream infection by multidrug-resistant organisms in critically ill patients in a reference trauma hospital.

BACKGROUND: Bloodstream infections (BSI) by multidrug-resistant (MDR) organisms are responsible for significant mortality in critically ill trauma patients. Our objective is to identify the risk factors for BSI by MDR agents and their resistance mechanisms in a trauma reference hospital. METHODS: During 18 months, all patients admitted in our Intensive Care Unit (ICU) were enrolled in this prospective cohort. We included the first episode of BSI by carbapenem-resistant Gram-negative bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococcus. Demographic and clinical data were compared among patients with and without BSI and variables with P < .05 were tested in a multivariate analysis. We performed PCR for identification of carbapenemase and SCC mec genes and Pulsed-field gel electrophoresis for clonality. RESULTS: Out of 1,528 patients, 302 (19.8%) were trauma and 66 (4.3%) had a MDR-BSI (19.5% were trauma). The multivariate analysis showed that mechanical ventilation (OR3.16; 95% CI 1-8; P = .02), hemodialysis (OR3.16; 95% CI 1-5; P = .0003) and surgery (OR1.76; 95% CI 1-3; P = .04) were independent risk factors for MDR-BSI. The most frequent MDR were Klebsiella pneumoniae (n = 26) and MRSA (n = 27). Regarding K pneumoniae strains (n = 24), 20 (83.8%) harbored bla KPC gene and 1 bla NDM. The majority of KPC isolates belonged to a predominant clone; while the MRSA were polyclonal and SCC mec type II. CONCLUSIONS: Mechanical ventilation, surgery and hemodialysis were independent risk factors for MDR-BSI in our cohort, but trauma was not. KPC was the main mechanism of resistance among carbapenem-resistant K pneumoniae that belonged to a predominant clone which could indicate cross-transmission.

Prevalence of methicillin-resistant Staphylococcus aureus colonization in individuals from the community in the city of Sao Paulo, Brazil.

Staphylococcus aureus (SA) is a commensal habitant of nasal cavities and skin. Colonization by community-acquired methicillin-resistant SA (CA-MRSA) is associated with infections in patients who have not been recently hospitalized. The aim of this study is to determine the prevalence of MRSA colonization in an outpatient population, currently unknown in Brazil. Three-hundred patients or caregivers from two teaching hospitals were included. A questionnaire was applied and nasal swabs were obtained from patients. Swabs were inoculated in brain heart infusion (BHI) with 2.5% NaCl and seeded in mannitol. Suspicious colonies were subjected to MALDI-TOF MS Microflex™ identification. Antimicrobial susceptibility test for oxacillin was performed for SA-positive samples by microdilution. Polymerase chain-reactions for detection of mecA and coA genes were performed for resistant samples. Data about MRSA carriers were compared with non-carriers. There were 127 S. aureus isolates, confirmed by MALDI-TOF. Only seven (2.3%) were MRSA and positive for mecA and coA genes. Factors associated with MRSA carriage were African ethnicity, skin diseases or antibiotic use. The majority of them were from Dermatology clinics. Prevalence of MRSA colonization in individuals from the community was low in our study (2.3%). This finding raises the hypothesis of inter-household transmission of SA, although we did not find any association between MRSA-colonization and the shared use of personal objects. Given the low prevalence of MRSA carriers observed, empirical antimicrobial coverage for MRSA in community-acquired infections should be not necessary.

Evaluation of two methods for direct detection of Fusarium spp. in water.

Fusarium is a waterborne fungus that causes severe infections especially in patients with prolonged neutropenia. Traditionally, the detection of Fusarium in water is done by culturing which is difficult and time consuming. A faster method is necessary to prevent exposure of susceptible patients to contaminated water. The objective of this study was to develop a molecular technique for direct detection of Fusarium in water. A direct DNA extraction method from water was developed and coupled to a genus-specific PCR, to detect 3 species of Fusarium (verticillioides, oxysporum and solani). The detection limits were 10 cells/L and 1 cell/L for the molecular and culture methods, respectively. To our knowledge, this is the first method developed to detect Fusarium directly from water.