High Genetic Diversity among Stenotrophomonas maltophilia Strains Despite Their Originating at a Single Hospital

Abstract

The levels of genetic relatedness of 139 Stenotrophomonas maltophilia strains recovered from 105 hospitalized non-cystic fibrosis patients (51% from medical wards, 35% from intensive care units, and 14% from surgical wards) and 7 environmental sources in the same hospital setting during a 4-year period were typed by the pulsed-field gel electrophoresis (PFGE) technique. A total of 99 well-defined distinct XbaI PFGE patterns were identified (Simpson's discrimination index, 0.996). The dendrogram showed a Dice similarity coefficient ranging from 28 to 80%. Two major clusters (I and II), three minor clusters (III, IV, and V), and two independent branches were observed when using a 36% Dice coefficient, indicating a high diversity of genetic relatedness. It is of note that 84% of strains were grouped within two major clonal lineages. No special cluster gathering was found among strains belonging to the same sample type specimen, patients' infection or colonization status, and ward of precedence. Despite this fact, three different clones (A, B, and C) recovered from respiratory samples from six, three, and two patients, respectively, and two clones, D and E, in two bacteremic patients each, were identified. Isolation of an S. maltophilia strain belonging to the clone A profile in a bronchoscope demonstrated a common source from this clone. This study revealed a high genetic diversity of S. maltophilia isolates despite their origin from a single hospital, which may be related to the wide environmental distribution of this pathogen. However, few clones could be transmitted among different patients, yielding outbreak situations.

Infection Prevention and Control Guideline for Cystic Fibrosis: 2013 Update

“…140,320 In general, genotyping analyses have not shown that isolates obtained from the hospital environmental are the same as those recovered from patients, 141,320 and the majority of non-CF patients infected with S. maltophilia had genetically distinct strains. 321 None of 24 S. maltophilia isolates recovered from water, taps, and sinks in patient rooms matched the strains recovered from individuals with CF.…”

A Stenotrophomonas maltophilia Multilocus Sequence Typing Scheme for Inferring Population Structure

“…Many typing approaches have revealed that this species is of high genodiversity. Genotyping of isolates from hospitalized CF and non-CF patients by PFGE or randomly amplified polymorphic DNA PCR revealed a high degree of diversity with changes in the strains consecutively isolated from CF patients (18,38,70,71). A multilocus enzyme electrophoresis scheme has been proposed for investigations of hospital epidemiology (60).…”

Immunostimulatory Properties of the Emerging Pathogen Stenotrophomonas maltophilia

“…Although rarely associated with septic shock, S. maltophilia commonly causes persistent bacteremia and is frequently associated with respiratory tract and catheter-related infections. An analysis of 139 isolates from 105 non-CF patients established that S. maltophilia was a cause of infection in the central nervous system, bone, bloodstream, and urinary tract, as well as the respiratory tract (37). Many case reports have demonstrated the potential of S. maltophilia to cause invasive infection as an opportunistic pathogen in immunocompromised patients (24) or when it is inadvertently introduced into a normally sterile site (20).…”