Genetic diversity of clinical Pseudomonas aeruginosa isolates in a public hospital in Spain.

BACKGROUND: Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple resistances to antibiotics with increasing frequency, making patient treatment more difficult. The aim of the study is to ascertain the population structure of this clinical pathogen in the Hospital Son Llàtzer, Spain. RESULTS: A significant set (56) of randomly selected clinical P. aeruginosa isolates, including multidrug and non-multidrug resistant isolates, were assigned to sequence types (STs) and compared them with their antibiotic susceptibility profile classified as follows: extensively drug resistant (XDR), multidrug resistant (MDR) and non-multidrug resistant (non-MDR). The genetic diversity was assessed by applying the multilocus sequence typing (MLST) scheme developed by Curran and collaborators, and by the phylogenetic analysis of a concatenated tree. The analysis of seven loci, acsA, aroE, guaA, mutL, nuoD, ppsA and trpE, demonstrated that the prevalent STs were ST-175, ST-235 and ST-253. The majority of the XDR and MDR isolates were included in ST-175 and ST-235. ST-253 is the third in frequency and included non-MDR isolates. The 26 singleton sequence types corresponded mainly to non-MDR isolates. Twenty-two isolates corresponded to new sequence types (not previously defined) of which 12 isolates were non-MDR and 10 isolates were MDR or XDR. CONCLUSIONS: The population structure of clinical P. aeruginosa present in our hospital indicates the coexistence of nonresistant and resistant isolates with the same sequence type. The multiresistant isolates studied are grouped in the prevalent sequence types found in other Spanish hospitals and at the international level, and the susceptible isolates correspond mainly to singleton sequence types.

Factors associated with readmission and mortality in adult patients with skin and soft tissue infections.

BACKGROUND: Skin and soft tissue infections (SSTIs) are a common cause of consultation, and complicated cases require hospitalization. We describe factors that are related to readmission and/or mortality of hospitalized patients diagnosed with SSTIs. METHODS: Retrospective review of hospital-admitted patients with a diagnosis of cellulitis, abscess, hidradenitis, fasciitis, and Fournier's gangrene. Cases from January 2002 to October 2015 were extracted from the diagnostic codification database of the Archives and Clinical Documentation Department. FINDINGS: We studied 1,482 episodes of hospitalized patients diagnosed with SSTIs. There were 187 (12.3%) readmissions, the most frequent diagnosis was cellulitis (72.7%), and the most commonly isolated microorganism was Staphylococcus aureus (25; 30.1%). Factors associated with readmissions were healthcare-related infections (P = 0.002), prior antibiotic therapy (P < 0.001), ischemic heart disease (P = 0.01), chronic liver disease (P = 0.001), and diabetes mellitus (DM) (P = 0.006). The number of patients who died as a result of an infection was 34 (2.2%) and, in these patients, the most common diagnosis was also cellulitis (79.4%), which in 52.9% (P = 0.001) was community acquired. DM (P = 0.01), heart failure (P = 0.001), and chronic liver disease (P = 0.003) were the most frequent comorbidities. This group presented more complications (P < 0.005) such as endocarditis (P < 0.005), amputation (P = 0.018), severe sepsis (P < 0.005), and septic shock (P < 0.001). CONCLUSIONS: Readmitted patients had healthcare-related S. aureus infection, had received prior antibiotic therapy, and presented comorbid conditions such as ischemic heart disease, peripheral vascular disease, chronic liver disease, or DM. Comorbidities such as advanced age, DM, heart failure, and chronic liver disease were associated with complications and higher infection-related mortality.