Objectives: This study aimed to characterise all carbapenemase-producing enterobacteria (CPE) isolates obtained from an outbreak-free setting in Uruguay. Methods: We studied 12 CPE isolated from Hospital de Clinicas between 2012-2016. Bacterial identification and antibiotic susceptibility testing were performed using VITEK (R) 2 and Sensititre or agar dilution, respectively. Antimicrobial resistance genes and mobile genetic elements were identified by PCR and sequencing. Multilocus sequence typing was performed for Klebsiella pneumoniae. Plasmid conjugation was assessed, plasmid size was estimated by S1-PFGE and plasmid incompatibility groups were sought by PCR. Results: Among 8364 enterobacteria, 12 CPE were isolated from urine, blood culture, wound, peritoneal fluid and punch samples. NDM-1 was the most prevalent carbapenemase, followed by VIM-2 and KPC-2. All isolates were resistant to gentamicin, cefotaxime, ceftazidime, trimethoprim/sulfamethoxazole, ciprofloxacin and imipenem and were susceptible to fosfomycin. We characterised six class 1 integrons: dfrA12-orfF-aadA2; aacA4-blaOXA-2-orfD; aadB-aadA2; dfrA1; aadB-blaOXA-10-aadA1; and bla(VIM-2)-dfrA7. An association between various aminoglycoside, beta-lactam and fluoroquinolone resistance genes were observed, some of them located in transferable plasmids belonging to incompatibility groups IncC, IncHI1 and IncM1. We described a new composite transposon (assigned Tn6935) including bla(NDM-1) flanked by two directly-oriented copies of a Tn3-like element ISKox2-like family transposase. The sequence types of K. pneumoniae isolates were ST11, ST14 and ST661. Conclusions: The presence of CPE is sporadic and could be due to measures taken by the Public Health Committee. Nevertheless, the coexistence of several resistance mechanisms and their presence in conjugative plasmids and high-risk clones is worrisome. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.

Background: Biofilm involving infections are difficult to eradicate, mainly because bacteria forming these communities are more resistant to antimicrobials compared to their planktonic counterparts. Among 65-80% of healthcare infections are caused by microorganism that form biofilms in tissues or inanimate surfaces.

Background: Nosocomial infections are a major health problem, with high health and economic burden. Numerous strategies have been developed to prevent and diminish them. One important risk factors to acquire nosocomial infections is being hospitalized in intensive care units (ICU). Multidrug-resistant Gram-negative bacteria (MDR-GNB) are more frequent among these infections, and patient's gastrointestinal tract is an important reservoir. Methods & Materials: We analyzed 3 periods of prospective studies were gastrointestinal colonization was investigated and we looked for clinical infections and its etiology once the patient was discharged from the ICU. The studies were carried out in Hospital de Clínicas, a university referral hospital in 2010-2011, 2014-2015 and 2016-2017. Patients with more than 48 hours of invasive mechanical ventilation were included. Data from patients were collected and later nosocomial infections in moderate care were registered. All patients included were followed until death or discharge. Pharyngeal and rectal swabs were taken before ICU discharge and were cultured in MacConkey Lactose with and without 1 μg/ml ceftriaxone. Results: 227 patients were included, 31 clinical isolates from later nosocomial infections were found in Hospitals records, and 10 of these presented the same bacteria in clinical and swabs isolates. This data shows that approximately 14% (31/227) of patients had a later nosocomial infection with at least one clinical isolate and that 30% (10/31) of these were colonizing patient's gastrointestinal tract. Conclusion: Data reviewed supports the fact that knowing the "colonization status" at ICU discharge helps predicting the etiology of later nosocomial infections in the third part of cases. Given the difficulty for microbiology diagnose in many nosocomial infections, we think that empirical treatment could be based in results of rectal and pharyngeal swabs. We believe that more nosocomial infections are diagnosed but no clinical isolate is recovered. To sort these limitations, we continue enrolling patients in our case-control study.

Objectives: This study aimed to describe the characteristics of clinical isolates of extended-spectrum beta-lactamase (ESBL)-producing enterobacteria (EPE) in Uruguay's paediatric hospital.Methods: ESBLs, qnr alleles and aac(60)-Ib-cr were sought and characterised in EPE isolated between March 2010 and March 2012. Transfer of resistance determinants was assessed by conjugation. Incompatibility (Inc) groups, plasmid toxin-antitoxin systems (TAS) and plasmid size were determined in transconjugants. Clonality was analysed by pulsed-field gel electrophoresis. Multilocus sequence typing was done for ESBL-producing Klebsiella pneumoniae.Results: A total of 77 EPE isolates were characterised, comprising 43% K. pneumoniae, 19.5% Serratia marcescens, 19.5% Escherichia coli, 17% Enterobacter cloacae and 1% Klebsiella oxytoca. ESBLs belonged mainly to the blaCTX-M family (69.6%) [ bla(CTX-M-15) (45%) and bla(CTX-M-2) (31%)]. The aac(6')-Ib-cr/qnrB duplex was the most frequently detected plasmid-mediated quinolone resistance mechanism; this association was detected in K. pneumoniae harbouring bla(CTX-M-15). Transconjugants were obtained for 71% of the EPE. Amongst transconjugants, certain combinations were found between ESBLs and Inc group, e.g. IncA/C-bla(CTX-M-2), IncHI1/ HI2-bla(CTX-M-9) and IncHI1/ HI2-bla(SHV-12). In addition, the combination ccdABblaCTX-M-15 was also found. K. pneumoniae isolates harbouring bla(CTX-M-15)/aac(6')-Ib-cr/qnrB showed allodemic behaviour, with a predominance of ST14, ST45 and ST48.Conclusions: In this study, epidemiological changes in ESBL distribution could be explained by the spread of K. pneumoniae harbouring bla(CTX-M-15)/aac(6')-Ib-cr/qnrB, encoded mainly on conjugative plasmids featuring ccdAB TAS. Since reports of TAS in K. pneumoniae plasmids are scarce, new strategies are needed to combat intrinsic selection pressure exerted by the association, in conjugative plasmids, of resistance mechanisms with TAS. (C) 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

OBJECTIVES:This study aimed to describe the characteristics of clinical isolates of extended-spectrum β-lactamase (ESBL)-producing enterobacteria (EPE) in Uruguay's paediatric hospital. METHODS:ESBLs, qnr alleles and aac(6')-Ib-cr were sought and characterised in EPE isolated between March 2010 and March 2012. Transfer of resistance determinants was assessed by conjugation. Incompatibility (Inc) groups, plasmid toxin-antitoxin systems (TAS) and plasmid size were determined in transconjugants. Clonality was analysed by pulsed-field gel electrophoresis. Multilocus sequence typing was done for ESBL-producing Klebsiella pneumoniae. RESULTS:A total of 77 EPE isolates were characterised, comprising 43% K. pneumoniae, 19.5% Serratia marcescens, 19.5% Escherichia coli, 17% Enterobacter cloacae and 1% Klebsiella oxytoca. ESBLs belonged mainly to the blaCTX-M family (69.6%) [blaCTX-M-15 (45%) and blaCTX-M-2 (31%)]. The aac(6')-Ib-cr/qnrB duplex was the most frequently detected plasmid-mediated quinolone resistance mechanism; this association was detected in K. pneumoniae harbouring blaCTX-M-15. Transconjugants were obtained for 71% of the EPE. Amongst transconjugants, certain combinations were found between ESBLs and Inc group, e.g. IncA/C-blaCTX-M-2, IncHI1/HI2-blaCTX-M-9 and IncHI1/HI2-blaSHV-12. In addition, the combination ccdAB-blaCTX-M-15 was also found. K. pneumoniae isolates harbouring blaCTX-M-15/aac(6')-Ib-cr/qnrB showed allodemic behaviour, with a predominance of ST14, ST45 and ST48. CONCLUSIONS:In this study, epidemiological changes in ESBL distribution could be explained by the spread of K. pneumoniae harbouring blaCTX-M-15/aac(6')-Ib-cr/qnrB, encoded mainly on conjugative plasmids featuring ccdAB TAS. Since reports of TAS in K. pneumoniae plasmids are scarce, new strategies are needed to combat intrinsic selection pressure exerted by the association, in conjugative plasmids, of resistance mechanisms with TAS.

We report the first detection of bla CTX-M-19 in South America, harboured in an Escherichia coli isolate obtained from a urine sample; such an isolate belonged to phylogenetic group A, ST603, and showed a ceftazidimase profile. bla CTX-M-19 was encoded in an approximately 100 kb IncI1/IncF conjugative plasmid, featuring pndAC and hok/sok addiction systems; the β-lactamase gene was flanked upstream by three tandem-like transposons (IS26, IS10 and ISEcp1), inserted one inside the other, and downstream by IS903.