Profiling of rpoB mutations and MICs for rifampin and rifabutin in Mycobacterium tuberculosis.

Resistance to rifampin (RIF) and rifabutin (RFB) in Mycobacterium tuberculosis is associated with mutations within an 81-bp region of the rpoB gene (RIF resistance-determining region [RRDR]). Previous studies have shown that certain mutations in this region are more likely to confer high levels of RIF resistance, while others may be found in phenotypically susceptible isolates. In this study, we sought to determine the relationship between the MICs of RIF and RFB and rpoB RRDR mutations in 32 multidrug-resistant (MDR), 4 RIF-monoresistant, and 5 susceptible M. tuberculosis clinical isolates. The MICs were determined using the MGIT 960 system. Mutations in the rpoB RRDR were determined by Sanger sequencing. RpoB proteins with mutations S531L (a change of S to L at position 531), S531W, H526Y, and H526D and the double mutation D516A-R529Q were associated with high MICs for RIF and RFB. Five isolates carrying the mutations L511P, H526L, H526N, and D516G-S522L were found to be susceptible to RIF. Several mutations were associated with resistance to RIF and susceptibility to RFB (F514FF, D516V, and S522L). Whole-genome sequencing of two MDR isolates without rpoB RRDR mutations revealed a mutation outside the RRDR (V146F; RIF MIC of 50 µg/ml). The implications of the polymorphisms identified in the second of these isolates in RIF resistance need to be further explored. Our study further establishes a correlation between the mutations and the MICs of RIF and, also, RFB in M. tuberculosis. Several rpoB mutations were identified in RIF- and RFB-susceptible isolates. The clinical significance of these findings requires further exploration. Until then, a combination of phenotypic and molecular testing is advisable for drug susceptibility testing.

Epidemiology of healthcare-associated Pseudomonas aeruginosa in intensive care units: are sink drains to blame?

BACKGROUND: Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU). AIM: To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission. METHODS: This was a prospective cohort study of patients in six ICUs from 2018 to 2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial-resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples. All PA isolates underwent whole-genome sequencing. PA-HAI was defined using US National Healthcare Safety Network criteria. ICU-acquired PA was defined as PA isolated from specimens obtained ≥48 h after ICU admission in those with prior negative rectal swabs. Sink-to-patient PA transmission was defined as ICU-acquired PA with close genomic relationship to isolate(s) previously recovered from sinks in a room/bedspace occupied 3-14 days prior to collection date of the relevant patient specimen. FINDINGS: Over ten months, 72 PA-HAIs occurred among 60/4263 admissions. The rate of PA-HAI was 2.40 per 1000 patient-ICU-days; higher in patients who were PA-colonized on admission. PA-HAI was associated with longer stay (median: 26 vs 3 days uninfected; P < 0.001) and contributed to death in 22/60 cases (36.7%). Fifty-eight admissions with ICU-acquired PA were identified, contributing 35/72 (48.6%) PA-HAIs. Four patients with five PA-HAIs (6.9%) had closely related isolates previously recovered from their room/bedspace sinks. CONCLUSION: Nearly half of PA causing HAI appeared to be acquired in ICUs, and 7% of PA-HAIs were associated with sink-to-patient transmission. Sinks may be an under-recognized reservoir for HAIs.

Correction: Isolation of five Enterobacteriaceae species harbouring blaNDM-1 and mcr-1 plasmids from a single paediatric patient.

[This corrects the article DOI: 10.1371/journal.pone.0221960.].

Isolation of five Enterobacteriaceae species harbouring blaNDM-1 and mcr-1 plasmids from a single paediatric patient.

In Argentina, NDM metallo-ß-lactamase was first reported in 2013. By now, it has disseminated throughout the country in diverse Gram negative bacteria. Here, we report the case of a paediatric patient that underwent a 1-year hospitalisation due to erythrodermic psoriasis in 2014 and received multiple antimicrobial treatments. During his stay, five isolates were obtained from rectal swabs (rs) or blood culture (bc) suspicious of carbapenemase production: a K. quasipneumoniae subsp. quasipneumoniae (rs), Citrobacter freundii (rs), Escherichia coli (bc), Enterobacter cloacae (rs), and a Serratia marcescens (bc). The isolates were studied with broth microdilution, biparental conjugation and plasmid and whole genome sequencing (Illumina). All isolates harboured an 138,998-bp type 1 IncC plasmid that carried blaNDM-1, bleMBL, blaCMY-6, rmtC, aac(6')-Ib, and sul1 resistance genes. Additionally, the blaNDM-plasmids contained ISKpn8 an insertion sequence previously described as associated only to blaKPC. One isolate, a colistin-resistant E. coli, also carried a mcr-1-containing an IncI2 plasmid, which did not harbour additional resistance. The whole genome of K. quasipneumoniae subsp. quasipneumoniae isolate was fully sequenced. This isolate harboured, additionally to blaNDM, three plasmid-mediated quinolone resistance genes: qnrB4, qnrB52 and aac(6')-Ib-cr1. The E. cloacae isolate also harboured qnrA1. These findings alert to the underestimated horizontal dissemination of multidrug-resistant plasmids limiting treatment options with last resort antimicrobials.

Canadian recommendations for laboratory interpretation of multiple or extensive drug resistance in clinical isolates of Enterobacteriaceae, Acinetobacter species and Pseudomonas aeruginosa.

The goal of this document was to provide Canadian laboratories with a framework for consistent reporting and monitoring of multidrug resistant organisms (MDRO) and extensively drug resistant organisms (XDRO) for common gram-negative pathogens. This is the final edition of the interim recommendations, which were modified after one year of broad consultative review. This edition represents a consensus of peer-reviewed information and was co-authored by the Canadian Public Health Laboratory Network and the Canadian Association of Clinical Microbiology and Infectious Diseases. There are two main recommendations. The first recommendation provides standardized definitions for MDRO and XDRO for gram-negative organisms in clinical specimens. These definitions were limited to antibiotics that are commonly tested clinically and, to reduce ambiguity, resistance (rather than non-susceptibility) was used to calculate drug resistance status. The second recommendation identifies the use of standardized laboratory reporting of organisms identified as MDRO or XDRO. Through the broad consultation, which included public health and infection prevention and control colleagues, these definitions are ready to be applied for policy development. Both authoring organizations intend to review these recommendations regularly as antibiotic resistance testing evolves in Canada.

Novel class 1 Integrons and sequence types in VIM-2 and VIM-11-producing clinical strains of Enterobacter cloacae.

All VIM-producing Enterobacteriaceae (six Enterobacter cloacae) submitted to the Argentinian Reference Laboratory in Antimicrobial Resistance in the period 2008-13 were characterized. The isolates were referred from 6 nosocomial institutions located in 5 different cities across the country. All isolates showed carbapenem disk diffusion inhibition zones ≤22mm and synergism between a carbapenem disk and EDTA/SMA. The six isolates were PCR positive for blaVIM. Imipenem MICs were ≤1 to 8µg/ml. Typing by PFGE and MLST distinguished six pulsotypes and sequence types with blaVIM located on novel class 1 integron arrays: ECL-1: ST182, In883; ECL-2, ST90, In885; ECL-3, ST88, In346 with blaVIM-11; ECL-4, ST184, In900; ECL-5, ST749-new, In900; ECL-6, ST91 and uncharacterized In. Only ECL-2 was able to transfer blaVIM-2 to E. coli J53 by biparental conjugation. blaVIM was located in plasmids of 53-82Kb and in the chromosome (ECL-1 and ECL-5). The diversity of clones, class 1 integrons, plasmids and location of blaVIM, reveals the plasticity of the genetic elements described and highlights the importance of surveillance programs as tools to identify the transmission of these highly resistant metallo-ß-lactamase-producing Enterobacteriaceae.

First report of VanA Enterococcus gallinarum dissemination within an intensive care unit in Argentina.

Enterococcusgallinarum is intrinsically resistant to low levels of vancomycin and has been described as a colonizing microorganism causing bacteraemia and infection among immunosupresed patients. Between August 2000 and February 2001, 15 highly glycopeptide-resistant E. gallinarum isolates, one from blood and the remaining from rectal swabs, were recovered in a general hospital of Buenos Aires Province, Argentina. All isolates were characterized by biochemical assays, and displayed MICs of vancomycin in the range 16-128 mg/l and MICs of teicoplanin in the range 16-32 mg/l. In all cases, PCR analysis yield positive results for both vanC1 and vanA genes. E. gallinarum isolates were classified as two clonal types by SmaI-PFGE: clone A (n = 8) and clone B (n = 7) and both harboured a transferable vanA element.

[1st isolation of vancomycin-resistant Enterococcus faecium with the vanB genotype in Argentina: presentation of 2 cases]. / Primer aislamiento de Enterococcus faecium vancomicina-resistente con genotipo vanB en la Argentina: presentación de dos casos.

We describe the first isolate of van B vancomycin-resistant Enterococcus faecium in Argentina. The strains were recovered from ambulatory patients admitted to a hospital of Buenos Aires city in July 2000. They were not high-risk patients, they had not received previous antibiotic therapy, and they were assisted in different services. MICs for vancomycin were 32 micrograms/ml for both strains, whereas MICs for teicoplanin were 0.12 microgram/ml in case 1 and 0.25 microgram/ml in case 2. PCR was performed to confirm the vanB genotype. The molecular fingerprints of the isolations by PFGE revealed that they were identical. No further VanB strains were isolated in the hospital.

Clonal dissemination of Klebsiella pneumoniae ST258 harbouring KPC-2 in Argentina.

The present work describes the abrupt emergence of Klebsiella pneumoniae carbapenemase (KPC) and characterizes the first 79 KPC-producing enterobacteria from Argentina (isolated from 2006 to 2010). The emergence of bla(KPC-2) was characterized by two patterns of dispersion: the first was the sporadic occurrence in diverse enterobacteria from distant geographical regions, harbouring plasmids of different incompatibility groups and bla(KPC-2) in an unusual genetic environment flanked by ISKpn8-Δbla(TEM-1) and ISKpn6-like. bla(KPC-2) was associated with IncL/M transferable plasmids; the second was the abrupt clonal spread of K. pneumoniae ST258 harbouring bla(KPC-2) in Tn4401a.

Teenager donation: investigation of 848 high school students.

AIMS: The aims of this study were to quantify donors among the investigated area, quantify arguments and myths about the donation and transplantation process, and fix predetermined donation variables in a logistical model. MATERIALS AND METHODS: We used an analytical, prospective design, using 848 students from 13 high schools in the Velez Sarsfield Hospital area in an open-closed inquiry. RESULTS: Females were 57.74% and average age was 16.64 +/- 0.06 years, including 65.09% Catholics. The 642 potential donors represented 75% of the study population with the fundamental aim being to "give life" (44.85%). The 193 (22.75%) opposed subjects cited as a principal reason fear and distrust (40.41%). There were 40.21% who had discussed the donation subject with their families. In our study 76.41% believed that human organ traffic exists and 36.88% thought that it is due to corruption. Also, 56.01% fear premature extraction of their organs. In addition, 73.23% of teenagers considered that individuals who refused to donate have the right to receive organs (P = not significant between donors and not a donor). The family discussion and the lack of fear about premature extraction were donation signals. About the low level of donation 43.27% blamed the government (lack of campaigns, information, and knowledge) whereas other reasons were fear, lack of clarity and distrust. In our study 49.17% seemed to wish to increase donation if they received more information. CONCLUSIONS: Individuals predispose to donation represented the great majority of the queried teenagers; education and family discussion were remarkable factors favoring the decision.

Polimiositis: presentación inusual / Polymyositis: an unusual presentation

La miopatía inflamatoria aguda con severo edema subcutáneo es extremadamente rara y ha sido descripta en unos pocos casos. Presentamosun paciente con una polimiositis que cursó con edema localizado de tronco y miembros superiores.

Primer aislamiento de Enterococcus faecium vancomicina-resistente con genotipo vanB en la Argentina: presentación de dos casos / First isolate of vanB vancomycin-resistant Enterococcus faecium in Argentina: repor of two cases

En el presente trabajo se comunican los primeros aislamientos de Enterococcus faecium vanB, registrados en Argentina. Las cepas fueron aisladas de pacientes ambulatorias, sin internaciones recientes ni tratamiento antibiótico prolongado previo, atendidas en un hospital de Buenos Aires en julio de 2000. Las CIMs a vancomicina fueron de 32 µg/ml para ambos aislamientos y para teicoplanina 0,12 µg/ml en el caso 1 y 0,25 µg/ml en el caso 2. La detección genética de la resistencia a vancomicina se realizó por la reacción en cadena de la polimerasa con cebadores específicos para el genotipo vanB. Para determinar la relación de los aislamientos se realizó electroforesis en campo pulsado. El análisis del producto de la restricción demostró que ambos aislamientos fueron indistinguibles entre sí, no obstante no se registraron nuevos aislamientos vanB en el hospital.