Molecular Epidemiology, Antibiotic Resistance, and Virulence Traits of Stenotrophomonas maltophilia Strains Associated With an Outbreak in a Mexican Tertiary Care Hospital

Abstract

Stenotrophomonas maltophilia, an emerging opportunistic pathogen, is widely distributed in the environment the resistance mechanisms, and virulence factors of this bacterium facilitate its dissemination in hospitals. This study aimed to characterize the molecular epidemiology of S. maltophilia strains associated with an outbreak in the Children's Hospital of México Federico Gómez (HIMFG). Twenty-one clinical S. maltophilia strains were recovered from cultures of blood and urine samples from 10 pediatric patients at the emergency department, and nine environmental S. maltophilia strains recovered from faucets in the same area were also included. Two of the 10 patients were related with health care-associated infections (HCAIs), and the other eight patients (8/10) were infected with environmental S. maltophilia strains. The outbreak was controlled by monthly disinfection of the faucets in the emergency department. Typing using pulsedfield gel electrophoresis (PFGE) showed a 52% genetic diversity with seven pulsotypes denoted P1-P7 among all S. maltophilia strains. Three pulsotypes (P2, P3, and P7) were identified among both the clinical and environmental S. maltophilia strains and associated with two type sequences (STs), namely, ST304 and ST24. Moreover, 80% (24/30) of the strains exhibited resistance mainly to tetracycline, 76.66% (23/30) to trimethoprimsulfamethoxazole, and 23.33% (7/30) to the extended-spectrum β-lactamase (ESBL) phenotype. The main resistance genes identified by multiplex PCR were sul1 in 100% (30/30), qnr in 86.66% (26/30), and intl1 in 80% (24/30) of the samples, respectively. Furthermore, the pilU, hlylII, and rmlA genes were identified in 96.6% (29/30), 90% (27/30), and 83.33% (25/30) of the samples, respectively. Additionally, 76.66% (23/30) of the S. maltophilia strains exhibited high swimming motility, 46.66% (14/30) showed moderate biofilm formation capacity, 43.33% (13/30) displayed moderate Cruz-Córdova et al. Outbreak Associated With Stenotrophomonas maltophilia twitching motility, and 20% (6/30) exhibited high adherence. The clinical S. maltophilia strains isolated from blood most strongly adhered to HTB-9 cells. In conclusion, the molecular epidemiology and some of the features such as resistance, and virulence genes associated with colonization patterns are pathogenic attributes that can promote S. maltophilia dissemination, persistence, and facilitate the outbreak that occurred in the HIMFG. This study supports the need for faucet disinfection as a control strategy for clinical outbreaks.

Biofilm Formation among Stenotrophomonas maltophilia Isolates Has Clinical Relevance: The ANSELM Prospective Multicenter Study

“…In agreement with previous studies [ 15 , 16 , 17 , 18 , 33 ], our findings showed that the ability to form biofilm is highly preserved in clinical S. maltophilia isolates, albeit with significant interstrain variability. Biofilm formation was noted among both the pathogenic and non-pathogenic strains, which suggests its essential role for bacterial persistence regardless of the colonization sites.…”

“…The isolates from blood showed the highest capacity for biofilm formation, while those isolated from airways of CF patients produced the lowest amounts of biofilm. Our findings are consistent with an increased adherence to human bladder HTB-9 cells by blood-derived S. maltophilia strains compared to those from environmental or urinary sources [17].…”

“…Recently, a handful of studies have reported the frequency and characterization of biofilm-producing S. maltophilia strains prospectively isolated from several hospitals worldwide. Overall, the findings revealed that biofilm formation is highly conserved in S. maltophilia and occurs with relevant efficacy leading to high biomass amount [ 2 , 5 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. However, these studies were aimed at investigating the phenotypic and genotypic characteristics or virulence traits, without providing evidence for the relationship between biofilm formation and the clinical course of diseases.…”

Isolation of Stenotrophomonas maltophilia from Clinical Samples in Some Hospitals in Shiraz, Iran

“…On the other hand, recent research report opined that 11% of Cystic Fibrosis (CF) patients can be infected by S. maltophilia. Thus, high incidence of infections due to S. maltophilia can be expected in immunocompromised patients [4]. Several factors such as intrinsic resistance to antimicrobial agents, production of proteolytic enzymes and other pathogenic extracellular enzymes such as DNase, RNase, elastase, lipase, hyaluronidase, mucinase and hemolysin [3].…”

Untitled

“…The transmission of S. maltophilia within the hospital setting is rarely seen, and it usually occurs as a result of a cross-contamination issue [30]. Nevertheless, contained S. maltophilia outbreaks within the ICU of a hospital setting have been reported associated with contaminated bronchoscopes [12], and superficial surfaces near the patient, such as shower outlets [31], faucets [32] and drinking water supplying devices for ICU patients [33].…”