scholarly journals Distinct epidemiology and resistance mechanisms affecting ceftolozane/tazobactam in Pseudomonas aeruginosa isolates recovered from ICU patients in Spain and Portugal depicted by WGS

Author(s):  
Marta Hernández-García ◽  
María García-Castillo ◽  
Sergio García-Fernández ◽  
José Melo-Cristino ◽  
Margarida F Pinto ◽  
...  

Abstract Objectives To analyse the epidemiology, the resistome and the virulome of ceftolozane/tazobactam-susceptible or -resistant Pseudomonas aeruginosa clinical isolates recovered from surveillance studies in Portugal (STEP, 2017–18) and Spain (SUPERIOR, 2016–17). Methods P. aeruginosa isolates were recovered from intra-abdominal, urinary tract and lower respiratory tract infections in ICU patients admitted to 11 Portuguese and 8 Spanish hospitals. MICs were determined (ISO-standard broth microdilution, EUCAST 2020 breakpoints). A subset of 28 ceftolozane/tazobactam-resistant P. aeruginosa isolates were analysed and compared with 28 ceftolozane/tazobactam-susceptible P. aeruginosa strains by WGS. Results Clonal complex (CC) 235 (27%) and CC175 (18%) were the most frequent, followed by CC244 (13%), CC348 (9%), CC253 (5%) and CC309 (5%). Inter-hospital clonal dissemination was observed, limited to a geographical region (CC235, CC244, CC348 and CC253 in Portugal and CC175 and CC309 in Spain). Carbapenemases were detected in 25 isolates (45%): GES-13 (13/25); VIM type (10/25) [VIM-2 (4/10), VIM-20 (3/10), VIM-1 (2/10) and VIM-36 (1/10)]; and KPC-3 (2/25). GES-13-CC235 (13/15) and VIM type-CC175 (5/10) associations were observed. Interestingly, KPC-3 and VIM-36 producers showed ceftolozane/tazobactam-susceptible phenotypes. However, ceftolozane/tazobactam resistance was significantly associated with GES-13 and VIM-type carbapenemase production. Six non-carbapenemase producers also displayed ceftolozane/tazobactam resistance, three of them showing known ceftolozane/tazobactam resistance-associated mutations in the PBP3 gene, ftsI (R504C and F533L). Overall, an extensive virulome was identified in all P. aeruginosa isolates, particularly in carbapenemase-producing strains. Conclusions GES-13-CC235 and VIM type-CC175 were the most frequent MDR/XDR P. aeruginosa clones causing infections in Portuguese and Spanish ICU patients, respectively. Ceftolozane/tazobactam resistance was mainly due to carbapenemase production, although mutations in PBP-encoding genes may additionally be involved.

2021 ◽  
Vol 10 (35) ◽  
pp. 2964-2968
Author(s):  
Swetha Thirumurthi ◽  
Priya Kanagamuthu ◽  
Rajasekaran Srinivasan ◽  
Bhalaji Dhanasekaran

BACKGROUND The term tracheostomy refers to forming an opening in the trachea.1,2 Its advantages include easy and direct access to lower respiratory tract, reduced risk of aspiration, faster weaning from ventilation support and improved physical and psychological comfort. But a common problem in tracheostomised patients is increased risk of colonisation of lower respiratory tract by exogenous bacteria because of direct exposure.1,3 This study was done to recognise pathogens in tracheal secretions collected from tracheostomised patients and their antibiotic sensitivity to treat them with appropriate antibiotics. METHODS This prospective study was done in 138 tracheostomised patients from October 2020 to March 2021 in intensive care unit (ICU) of Chettinad Hospital and Research Institute. Under sterile aseptic precautions, Day 0 and Day 7 cultures posttracheostomy was obtained and their antibiotic sensitivity was studied. Data was analysed using Statistical Package for Social Sciences (SPSS version 19) and presented in proportion, mean and standard deviation (Descriptive statistics). RESULTS In this study, of the 56 cases who had growth in their culture and sensitivity reports on day 0, the most common organism was Pseudomonas aeruginosa (33.9 %) sensitive to imipenem (94.7 %) followed by klebsiella (25 %) sensitive to teicoplanin, vancomycin, amikacin, cefoperazone/tazobactam, linezolid and piperacillin/tazobactam. On day 7, the growth of organisms isolated in tracheal culture got reduced from 56 cases to 16 cases. The prevalence of Pseudomonas reduced to 18.8 % in day 7 whereas Klebsiella pneumonia and Acinetobacter remained almost same from day 0 to day 7. CONCLUSIONS This study concludes the predominant pathogen as Pseudomonas aeruginosa with sensitivity to imipenem followed by Klebsiella with sensitivity to teicoplanin, vancomycin, amikacin, cefoperazone/tazobactam, linezolid and piperacillin/tazobactam on day 0 with reduction in the number of organisms on day 7 due to the fact that all our patients were admitted in ICU several days prior to tracheostomy and were started on antibiotics soon after admission as per choice of the treating physician. Hence, a clear understanding of bacterial colonisation post tracheostomy and its change in course is essential for timely intervention with empirical antibiotics for reducing the incidence of lower respiratory tract infections after tracheostomy in future. KEY WORDS Tracheostomy, Lower Respiratory Tract Infections, Pseudomonas Aeruginosa, Empirical Antibiotics.


Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 521
Author(s):  
Paola Navarro-Gómez ◽  
Jose Gutierrez-Fernandez ◽  
Manuel Angel Rodriguez-Maresca ◽  
Maria Carmen Olvera-Porcel ◽  
Antonio Sorlozano-Puerto

The objective of the study was to evaluate the capacity of GERH®-derived local resistance maps (LRMs) to predict antibiotic susceptibility profiles and recommend the appropriate empirical treatment for ICU patients with nosocomial infection. Data gathered between 2007 and 2016 were retrospectively studied to compare susceptibility information from antibiograms of microorganisms isolated in blood cultures, lower respiratory tract samples, and urine samples from all ICU patients meeting clinical criteria for infection with the susceptibility mapped by LRMs for these bacterial species. Susceptibility described by LRMs was concordant with in vitro study results in 73.9% of cases. The LRM-predicted outcome agreed with the antibiogram result in >90% of cases infected with the bacteria for which GERH® offers data on susceptibility to daptomycin, vancomycin, teicoplanin, linezolid, and rifampicin. Full adherence to LRM recommendations would have improved the percentage adequacy of empirical prescriptions by 2.2% for lower respiratory tract infections (p = 0.018), 3.1% for bacteremia (p = 0.07), and 5.3% for urinary tract infections (p = 0.142). LRMs may moderately improve the adequacy of empirical antibiotic therapy, especially for lower respiratory tract infections. LRMs recommend appropriate prescriptions in approximately 50% of cases but are less useful in patients with bacteremia or urinary tract infection.


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