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ABSTRACT: We document linezolid dependence among 5 highly linezolid-resistant (LRSE) Staphylococcus epidermidis bloodstream isolates that grew substantially faster at 32 µg/mL linezolid presence. These isolates carried the mutations T2504A and C2534T in multiple 23S rRNA copies and 2 mutations leading to relevant amino acid substitutions in L3 protein. Linezolid dependence could account for increasing LRSE emergence.
Emerging Infectious Diseases 01/2013; 19(1):129-32. · 6.79 Impact Factor
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ABSTRACT: OBJECTIVES: First detected in Enterobacteriaceae isolates in Turkey, the OXA-48 carbapenemase has gradually disseminated in the wider Mediterranean area and Europe. Despite reports from other European regions, until now no such isolates have been detected in Greece. We describe the characteristics of the first outbreak caused by OXA-48-producing Klebsiella pneumoniae in Greece. METHODS: From December 2011 to March 2012, 13 ertapenem-resistant K. pneumoniae isolates, which were positive by the modified Hodge test while remaining negative by phenotypic screening for metallo-β-lactamase (MBL) and KPC production, were recovered from nine patients. Patient records were retrieved to access patterns of acquisition. Resistance genes were identified by PCR and sequencing. ompK35, ompK36 and the genetic environment of the bla(OXA-48) gene were investigated. Plasmid profiling, conjugation experiments, PFGE and multilocus sequence typing (MLST) were performed. RESULTS: All isolates harboured the bla(OXA-48) gene along with the bla(CTX-M-15) and bla(OXA-1) genes. The bla(OXA-48) gene was located on a self-transferable IncL/M-type plasmid of ∼62 kb, which harboured no other resistance genes. IS1999 was located upstream of the bla(OXA-48) gene. Genetic disruptions of the ompK35 and ompK36 genes were not detected. The isolates belonged to a unique PFGE clone and MLST assigned them to sequence type ST11. All cases were characterized as hospital acquired and none of them was linked to immigration or history of travel in endemic areas. CONCLUSIONS: Carbapenem resistance due to MBL and KPC carbapenemases is currently on an endemic scale in Greece and this report highlights the wider undetected dissemination of yet another carbapenemase in this region.
Journal of Antimicrobial Chemotherapy 09/2012; · 5.07 Impact Factor
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ABSTRACT: Carbapenemase-producing Enterobacteriaceae (CPE) are an increasing problem worldwide, and rectal swab surveillance is recommended as a component of infection control programs. The performance of a prototype chromogenic medium (chromID CARBA) was evaluated and compared with media tested by four other screening methods: (i) overnight selective enrichment in 5 ml tryptic soy broth with a 10-μg ertapenem disk followed by plating onto MacConkey agar (CDC-TS), (ii) short selective enrichment in 9 ml brain heart infusion broth with a 10-μg ertapenem disk followed by plating onto chromID ESBL medium (ESBL-BH), (iii) direct plating onto chromID ESBL, and (iv) direct plating onto MacConkey agar supplemented with meropenem (1 μg/ml) (MCM). The screening methods were applied to detect CPE in 200 rectal swab specimens taken from different hospitalized patients. Identification and antimicrobial susceptibility were performed by the Vitek 2 system. Carbapenem MICs were checked by Etest. Carbapenemase production was confirmed using the modified Hodge test, combined-disk tests, and PCR assays. In total, 133 presumptive CPE strains were detected. Phenotypic and genotypic assays confirmed 92 strains to be CPE (56 KPC-positive Klebsiella pneumoniae, 29 VIM-positive K. pneumoniae, and 7 KPC-positive Enterobacter aerogenes strains) recovered from 73 patients, while the remaining 41 strains were confirmed to be CPE negative (19 ESBL producers and 22 nonfermenters). chromID CARBA, ESBL-BH, and chromID ESBL exhibited the highest sensitivity (92.4%), followed by CDC-TS and MCM (89.1%) (P = 0.631). The specificity was greater for chromID CARBA (96.9%) and ESBL-BH (93.2%) than for CDC-TS (86.4%), MCM (85.2%), and chromID ESBL (84.7%) (P = 0.014). In conclusion, chromID CARBA was found to be a rapid and accurate culture screening method for active CPE surveillance.
Journal of clinical microbiology 03/2012; 50(6):1841-6. · 4.16 Impact Factor
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ABSTRACT: The extended-spectrum β-lactamase (ESBL) PER-1 initially disseminated among Pseudomonas aeruginosa strains in Turkey. Despite reports from other European countries, such strains have not been detected in Greece until now. We describe the first bla(PER-1)-positive P. aeruginosa isolates from Greece and their genetic environment.
From January 2008 to December 2009, 287 consecutive non-duplicate P. aeruginosa isolates with reduced susceptibility or resistance to ceftazidime (MIC >8 mg/L) were screened for ESBL production with a modified boronic acid-based double-disc synergy test. Phenotypically ESBL-positive isolates were subjected to agar dilution, PFGE and multilocus sequence typing (MLST). Broad-spectrum bla genes were identified by PCR and sequencing. Plasmid analysis and conjugation experiments were performed. The location of the bla(PER-1) gene was detected by Southern blotting and its genetic environment was characterized using inverse PCR.
Five isolates were phenotypically positive for ESBL production, exhibited resistance to cefepime, ceftazidime, aztreonam and meropenem, and carried the bla(PER-1) gene. MLST showed that they belonged to sequence type (ST) 235, which belongs to the international clonal complex 11. Four isolates had the same PFGE pattern. Southern blotting revealed the chromosomal location of the bla(PER-1) gene. Analysis of the bla(PER-1) flanking regions showed identity to transposon Tn1213 downstream and 1406 bp upstream of bla(PER-1). Further upstream, an orfA gene and ISPa12 were identified; both were truncated by the insertion of IS6100.
This study confirmed the presence of PER-1-producing P. aeruginosa strains in Greece. The chromosomal location of bla(PER-1), as part of a truncated transposon, suggests clonal expansion rather than horizontal gene transfer.
Journal of Antimicrobial Chemotherapy 11/2011; 67(2):357-61. · 5.07 Impact Factor
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ABSTRACT: A carbapenem-resistant Escherichia coli isolate was recovered from rectal swab of a 12-day-old female neonate, which was admitted to a Greek neonatal intensive care unit (NICU). Phenotypic testing, polymerase chain reaction assays with sequencing, and plasmid analysis revealed that the isolate harbored a plasmid-mediated bla(VIM-1) metallo-β-lactamase gene. The appearance of a metallo-β-lactamase-producing E. coli in NICU is worrisome. Further surveys are needed to determine whether such Enterobacteriaceae may also be spreading in other NICUs.
Microbial drug resistance (Larchmont, N.Y.) 11/2010; 17(1):105-8. · 1.99 Impact Factor
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ABSTRACT: To investigate the extrahospital dissemination of carbapenem-resistant Klebsiella pneumoniae isolates and the mechanisms of acquired resistance.
Patients who were referred to the outpatient department of Serres General Hospital with community-onset infections due to carbapenem-resistant K. pneumoniae isolates during August 2007-October 2008 were included in the study. The selected isolates were tested by determination of agar dilution MICs, phenotypic carbapenemase testing and PFGE. PCR and sequencing analyses were employed for identification of bla genes and mapping of the integron carrying the metallo-β-lactamase (MBL) gene. The location of the MBL allele was investigated by mating experiments, plasmid analysis and PCR assays.
Twenty-four carbapenem-resistant K. pneumoniae isolates causing urinary tract infections were recovered from 12 outpatients. Six of the patients presented with recurrent infections within a period of 1-6 months after the initial extrahospital isolation. All patients reported prior hospitalization within the preceding 4 months, whilst two were infected by carbapenem-resistant K. pneumoniae isolates during their previous hospitalization. Imipenem, meropenem and ertapenem MICs ranged from 8 to 64 mg/L, 4 to 32 mg/L and 8 to 128 mg/L, respectively. All studied isolates as well as those obtained from prior hospitalization belonged to a single PFGE clone. They harboured a plasmid-mediated bla(VIM-1) gene in an integron structure that has been previously described among K. pneumoniae isolates causing hospital-acquired infections in Greece.
This is the first study to document the dissemination of an MBL-producing K. pneumoniae strain in the community. The successful strain caused recurrent community-onset infections and was most likely acquired during patients' previous hospitalization.
Journal of Antimicrobial Chemotherapy 09/2010; 65(12):2538-42. · 5.07 Impact Factor
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ABSTRACT: Three patients admitted to a Greek hospital were infected with Serratia marcescens isolates that exhibited reduced susceptibility to carbapenems and harbored Klebsiella pneumoniae carbapenemase (KPC) enzymes. In two of these cases, the patients were initially infected by carbapenem-susceptible S. marcescens isolates. Molecular typing and plasmid analysis suggested that all three patients had clonally indistinguishable isolates of S. marcescens that acquired a plasmid-mediated bla(KPC-2) gene during the hospitalization.
Journal of clinical microbiology 05/2010; 48(7):2546-9. · 4.16 Impact Factor
