Rapid identification and susceptibility testing results are of importance for the early appropriate therapy of bloodstream infections. The ePlex (GenMark Diagnostics) blood culture identification ...(BCID) panels are fully automated PCR-based assays designed to identify Gram-positive and Gram-negative bacteria, fungi, and bacterial resistance genes within 1.5 h from positive blood culture. Consecutive non-duplicate positive blood culture episodes were tested by the ePlex system prospectively. The choice of panel(s) (Gram-positive, Gram-negative, and/or fungal pathogens) was defined by Gram-stained microscopy of blood culture-positive bottles (BacT/Alert; bioMérieux). Results with the ePlex panels were compared to the identification results obtained by standard culture-based workflow. In total, 216 positive blood culture episodes were evaluable, yielding 263 identification results. The sensitivity/positive predictive value for detection by the ePlex panels of targeted cultured isolates were 97% and 99% for the Gram-positive panel and 99% and 96% for the Gram-negative panel, resulting in overall agreement rates of 96% and 94% for the Gram-positive and Gram-negative panel, respectively. All 26 samples with targeted resistance results were correctly detected by the ePlex panels. The ePlex panels provided highly accurate results and proved to be an excellent diagnostic tool for the rapid identification of pathogens causing bloodstream infections. The short time to results may be of added value for optimizing the clinical management of patients with sepsis.
Rapid detection and confirmation of carbapenemases remains very challenging for diagnostic laboratories.
The objective of this study was to assess the performance of two new immunochromatographic ...(IC) commercial assays for the rapid detection of OXA-48-producing and KPC-producing Enterobacteriaceae in pure bacterial isolates.
A panel of 92 bacterial isolates predominantly including carbapenem-non-susceptible Enterobacteriaceae with previously defined carbapenem resistance mechanisms was tested. Then, 342 consecutive carbapenem-non-susceptible Enterobacteriaceae isolates referred to the reference laboratory were investigated prospectively in parallel with other phenotypic tests and with multiplex PCR and sequencing as the gold standard.
In the collection panel, each of the two IC assays correctly detected all 30 OXA-48-like-producing isolates and 25 KPC-producing isolates, whatever the species, their association with other β-lactamases and the level of resistance to carbapenems. All other carbapenemase producers and all non-carbapenemase-producing isolates yielded negative results with both tests. In the prospective evaluation, all OXA-48-like-producing Enterobacteriaceae isolates (n = 130) and KPC-producing Enterobacteriaceae isolates (n = 33) were correctly detected by the individual IC assays, while 179 non-OXA-48-like-producing and non-KPC-producing strains (137 non-carbapenemase producers and 42 isolates belonging to other carbapenemase family types) yielded negative results. Thus, each assay yielded 100% sensitivity and 100% specificity for the detection of OXA-48-like or KPC enzymes, respectively, at 15 min.
The two IC assays allow rapid and reliable direct confirmation of OXA-48 and KPC carbapenemases from culture colonies and appear to be very useful additions to the existing tests, obviating the need for more costly characterization by molecular amplification methods.
In Enterobacterales, the most common carbapenemases are Ambler's class A (KPC-like), class B (NDM-, VIM- or IMP-like) or class D (OXA-48-like) enzymes. This study describes the characterization of ...twenty-four OXA-23 or OXA-58 producing-Proteus mirabilis isolates recovered from human and veterinary samples from France and Belgium. Twenty-two P. mirabilis isolates producing either OXA-23 (n = 21) or OXA-58 (n = 1), collected between 2013 and 2018, as well as 2 reference strains isolated in 1996 and 2015 were fully sequenced. Phylogenetic analysis revealed that 22 of the 24 isolates, including the isolate from 1996, belonged to a single lineage that has disseminated in humans and animals over a long period of time. The bla
gene was located on the chromosome and was part of a composite transposon, Tn6703, bracketed by two copies of IS15∆II. Sequencing using Pacbio long read technology of OXA-23-producing P. mirabilis VAC allowed the assembly of a 55.5-kb structure encompassing the bla
gene in that isolate. By contrast to the bla
genes, the bla
gene of P. mirabilis CNR20130297 was identified on a 6-kb plasmid. The acquisition of the bla
gene on this plasmid involved XerC-XerD recombinases. Our results suggest that a major clone of OXA-23-producing P. mirabilis is circulating in France and Belgium since 1996.
Shortening the turn-around time (TAT) of positive blood culture (BC) identification (ID) and susceptibility results is essential to optimize antimicrobial treatment in patients with sepsis. We aimed ...to evaluate the impact on antimicrobial prescription of a modified workflow of positive BCs providing ID and partial susceptibility results for Enterobacteriaceae (EB), Pseudomonas aeruginosa and Staphylococcus aureus on the day of BC positivity detection. This study was divided into a pre-intervention period (P0) with a standard BC workflow followed by 2 intervention periods (P1, P2) with an identical modified workflow. ID was performed with MALDI-TOF MS from blood, on early or on overnight subcultures. According to ID results, rapid phenotypic assays were realized to detect third generation cephalosporin resistant EB/P. aeruginosa or methicillin resistant S. aureus. Results were transmitted to the antimicrobial stewardship team for patient's treatment revision. Times to ID, to susceptibility results and to optimal antimicrobial treatment (OAT) were compared across the three study periods. Overall, 134, 112 and 154 positive BC episodes in P0, P1 and P2 respectively were included in the analysis. Mean time to ID (28.3 hours in P0) was reduced by 65.3% in P1 (10.2 hours) and 61.8% in P2 (10.8 hours). Mean time to complete susceptibility results was reduced by 27.5% in P1 and 27% in P2, with results obtained after 32.4 and 32.6 hours compared to 44.7 hours in P0. Rapid tests allowed partial susceptibility results to be obtained after a mean time of 11.8 hours in P1 and 11.7 hours in P2. Mean time to OAT was decreased to 21.6 hours in P1 and to 17.9 hours in P2 compared to 36.1 hours in P0. Reducing TAT of positive BC with MALDI-TOF MS ID and rapid susceptibility testing accelerated prescription of targeted antimicrobial treatment thereby potentially improving the patients' clinical outcome.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
There is an urgent need for accurate and fast diagnostic tests capable of identifying carbapenemase producers. Here, we assessed the performance of a new multiplex lateral flow assay (OKN K -SeT) for ...the rapid detection of OXA-48-like, KPC and NDM carbapenemase-producing Enterobacteriaceae from culture colonies.
Two hundred collection isolates with characterized β-lactamase content and 183 non-duplicate consecutive isolates referred to two National Reference Centres over a 2 month period in 2016 were used to evaluate the OKN K -SeT assay.
The assay correctly detected all 42 OXA-48-like-, 27 KPC- and 30 NDM-producing isolates from the collection panel, including 7 isolates that co-produced NDM and OXA-181 carbapenemases. No cross-reactivity was observed with non-targeted carbapenemases ( n = 41) or with non-carbapenemase producers ( n = 60). Prospectively, all OXA-48-like ( n = 69), KPC ( n = 9) and NDM ( n = 19) carbapenemase-producing Enterobacteriaceae isolates were correctly detected, while 11 carbapenemase producers not targeted by the assay went undetected VIM ( n = 8) and OXA-23/OXA-58-like ( n = 3). Overall, the sensitivity and specificity of the assay were 100%.
The OKN assay is efficient, rapid and easy to implement in the workflow of a clinical microbiology laboratory for the confirmation of OXA-48, NDM and KPC carbapenemases. This test represents a powerful diagnostic tool as it enables the rapid detection of the most clinically important carbapenemases without the need for more costly and less frequently available molecular assays.
Carbapenemase-producing
have increasingly been reported worldwide, with an ever-increasing heterogeneity of carbapenem resistance mechanisms, depending on the bacterial species and the geographical ...location. OXA-198 is a plasmid-encoded class D β-lactamase involved in carbapenem resistance in one
isolate from Belgium. In the setting of a multicenter survey of carbapenem resistance in
strains in Belgian hospitals in 2013, three additional OXA-198-producing
isolates originating from patients hospitalized in one hospital were detected. To reveal the molecular mechanism underlying the reduced susceptibility to carbapenems, MIC determinations, whole-genome sequencing, and PCR analyses to confirm the genetic organization were performed. The plasmid harboring the
gene was characterized, along with the genetic relatedness of the four
isolates. The
gene was harbored on a class 1 integron carried by an ∼49-kb IncP-type plasmid proposed as IncP-11. The same plasmid was present in all four
isolates. Multilocus sequence typing revealed that the isolates all belonged to sequence type 446, and single-nucleotide polymorphism analysis revealed only a few differences between the isolates. This report describes the structure of a 49-kb plasmid harboring the
gene and presents the first description of OXA-198-producing
isolates associated with a hospital-associated cluster episode.
Following two studies conducted in 2005 and 2011, a third prevalence survey of multidrug-resistant microorganisms (MDRO) was organised in Belgian nursing homes (NHs) using a similar methodology. The ...aim was to measure the prevalence of carriage of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum β-lactamase producing Enterobacteriaceae (ESBLE) and carbapenemase-producing Enterobacteriaceae (CPE) in NH residents. Risk factors for MDRO carriage were also explored.
Up to 51 randomly selected residents per NH were screened for MDRO carriage by trained local nurses between June and October 2015. Rectal swabs were cultured for ESBLE, CPE and VRE, while pooled samples of nose, throat and perineum and chronic wound swabs were obtained for culture of MRSA. Antimicrobial susceptibility testing, molecular detection of resistance genes and strain genotyping were performed. Significant risk factors for MDRO colonization MDRO was determined by univariate and multivariable analysis.
Overall, 1447 residents from 29 NHs were enrolled. The mean weighted prevalence of ESBLE and MRSA colonization was 11.3% and 9.0%, respectively. Co-colonization occurred in 1.8% of the residents. VRE and CPE carriage were identified in only one resident each. Impaired mobility and recent treatment with fluoroquinolones or with combinations of sulphonamides and trimethoprim were identified as risk factors for ESBLE carriage, while for MRSA these were previous MRSA carriage/infection, a stay in several different hospital wards during the past year, and a recent treatment with nitrofuran derivatives. Current antacid use was a predictor for both ESBL and MRSA carriage.
In line with the evolution of MRSA and ESBL colonization/infection in hospitals, a decline in MRSA carriage and an increase in ESBLE prevalence was seen in Belgian NHs between 2005 and 2015. These results show that a systemic approach, including surveillance and enhancement of infection control and antimicrobial stewardship programs is needed in both acute and chronic care facilities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Frequent contact with human waste and liquid manure from intensive livestock breeding, and the increased loads of antibiotic-resistant bacteria that result, are believed to be responsible for the ...high carriage rates of ESBL-producing E. coli found in birds of prey (raptors) in Central Europe. To test this hypothesis against the influence of avian migration, we initiated a comparative analysis of faecal samples from wild birds found in Saxony-Anhalt in Germany and the Gobi-Desert in Mongolia, regions of dissimilar human and livestock population characteristics and agricultural practices. We sampled a total of 281 wild birds, mostly raptors with primarily north-to-south migration routes. We determined antimicrobial resistance, focusing on ESBL production, and unravelled the phylogenetic and clonal relatedness of identified ESBL-producing E. coli isolates using multi-locus sequence typing (MLST) and macrorestriction analyses. Surprisingly, the overall carriage rates (approximately 5%) and the proportion of ESBL-producers among E. coli (Germany: 13.8%, Mongolia: 10.8%) were similar in both regions. Whereas bla(CTX-M-1) predominated among German isolates (100%), bla(CTX-M-9) was the most prevalent in Mongolian isolates (75%). We identified sequence types (STs) that are well known in human and veterinary clinical ESBL-producing E. coli (ST12, ST117, ST167, ST648) and observed clonal relatedness between a Mongolian avian ESBL-E. coli (ST167) and a clinical isolate of the same ST that originated in a hospitalised patient in Europe. Our data suggest the influence of avian migratory species in the transmission of ESBL-producing E. coli and challenge the prevailing assumption that reducing human influence alone invariably leads to lower rates of antimicrobial resistance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We compared the performance of the Carba NP test and the Rosco Rapid CARB screen kit for detecting carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa. Both tests are rapid and ...highly sensitive; however, the Carba NP test showed superior specificity, and several uninterpretable results were observed with the Rapid CARB screen.
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