Ongoing dissemination of OXA-244 carbapenemase-producing Escherichia coli in Switzerland and their detection.

OXA-244 is a derivative of OXA-48 showing weaker carbapenemase activity, compromising the detection of corresponding producers in clinical laboratories. Since 2017, the Swiss National Reference Center for Emerging Antibiotic Resistance noticed an increased identification of OXA-244-producing Escherichia coli (n=15) within the country. Different methods (biochemical and immunoassay tests, screening culture media) were tested for the detection of OXA-244 producers. Whole genome sequencing was used to investigate the genetic relatedness between the isolates and the genetic structures at the origin of the acquisition of the bla <sub>OXA-244</sub> gene. The mSuperCARBA® medium and the NG-Test CARBA5 assay were found to be suitable tools for detecting all OXA-244-producing isolates. Other selective media did not perform optimally. Among the fifteen strains, five sequence types were identified, with ST38 being predominant. The bla <sub>OXA-244</sub> gene was located on the chromosome for all isolates. Overall, detection of OXA-244 producers is challenging and specific guidelines must be followed

Conjugative IncFI plasmids carrying CTX-M-15 among Escherichia coli ESBL producing isolates at a University hospital in Germany

<p>Abstract</p> <p>Background</p> <p>Multi-drug-resistant, extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, constitute an emerging public-health concern. Little data on the molecular epidemiology of ESBL producing <it>Escherichia coli </it>is available in Germany. Here we describe the prevalence and molecular epidemiology of ESBL producing-<it>Escherichia coli </it>isolates at a German University hospital.</p> <p>Methods</p> <p>We analysed 63 non-duplicate clinical ESBL isolates obtained over an 8-month period using PCR and sequence-based ESBL allele typing, plasmid replicon typing, phylogenetic group typing. Pulsed-field gel electrophoresis (PFGE) based genotyping and plasmid profiling was performed, as well as confirmatory DNA-based hybridization assays.</p> <p>Results</p> <p>Examination of the 63 <it>Escherichia coli </it>isolates revealed an almost equal distribution among the <it>E. coli </it>phylogenetic groups A, B1, B2 and D. High prevalence (36/63) of the CTX-M-15 gene was observed and an analysis of PFGE-based patterns revealed the presence of this CTX-M allele in multiple clones. Resistance to cefotaxime was a transferable trait and a commonly occurring 145.5 kb conjugative IncFI plasmid was detected in 65% of <it>E. coli </it>carrying the CTX-M-15 allele. The rate of transferable antibiotic resistances for GM, SXT, TET, GM-SXT-TET, SXT-TET and GM-TET was 33%, 61%, 61%, 27%, 44% and 11%, respectively. The remaining strains did not have a common IncFI plasmid but harboured transferable IncFI plasmids with sizes that ranged from 97 to 242.5 kb.</p> <p>Conclusion</p> <p>Our data demonstrate the presence of IncFI plasmids within the prevailing <it>E. coli </it>population in a hospital setting and suggest that the dissemination of CTX-M-15 allele is associated to lateral transfer of these well-adapted, conjugative IncFI plasmids among various <it>E. coli </it>genotypes.</p

Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses

<p>Abstract</p> <p>Background</p> <p>Black elderberries (<it>Sambucus nigra </it>L.) are well known as supportive agents against common cold and influenza. It is further known that bacterial super-infection during an influenza virus (IV) infection can lead to severe pneumonia. We have analyzed a standardized elderberry extract (Rubini, BerryPharma AG) for its antimicrobial and antiviral activity using the microtitre broth micro-dilution assay against three Gram-positive bacteria and one Gram-negative bacteria responsible for infections of the upper respiratory tract, as well as cell culture experiments for two different strains of influenza virus.</p> <p>Methods</p> <p>The antimicrobial activity of the elderberry extract was determined by bacterial growth experiments in liquid cultures using the extract at concentrations of 5%, 10%, 15% and 20%. The inhibitory effects were determined by plating the bacteria on agar plates. In addition, the inhibitory potential of the extract on the propagation of human pathogenic H5N1-type influenza A virus isolated from a patient and an influenza B virus strain was investigated using MTT and focus assays.</p> <p>Results</p> <p>For the first time, it was shown that a standardized elderberry liquid extract possesses antimicrobial activity against both Gram-positive bacteria of <it>Streptococcus pyogenes </it>and group C and G <it>Streptococci</it>, and the Gram-negative bacterium <it>Branhamella catarrhalis </it>in liquid cultures. The liquid extract also displays an inhibitory effect on the propagation of human pathogenic influenza viruses.</p> <p>Conclusion</p> <p>Rubini elderberry liquid extract is active against human pathogenic bacteria as well as influenza viruses. The activities shown suggest that additional and alternative approaches to combat infections might be provided by this natural product.</p

How valid are current diagnostic criteria for dental erosion?

In principle, there is agreement about the clinical diagnostic criteria for dental erosion, basically defined as cupping and grooving of the occlusal/incisal surfaces, shallow defects on smooth surfaces located coronal from the enamel–cementum junction with an intact cervical enamel rim and restorations rising above the adjacent tooth surface. This lesion characteristic was established from clinical experience and from observations in a small group of subjects with known exposure to acids rather than from systematic research. Their prevalence is higher in risk groups for dental erosion compared to subjects not particularly exposed to acids, but analytical epidemiological studies on random or cluster samples often fail to find a relation between occurrence or severity of lesions and any aetiological factor. Besides other aspects, this finding might be due to lack of validity with respect to diagnostic criteria. In particular, cupping and grooving might be an effect of abrasion as well as of erosion and their value for the specific diagnosis of erosion must be doubted. Knowledge about the validity of current diagnostic criteria of different forms of tooth wear is incomplete, therefore further research is needed

The usefulness of microscopic observation for drug susceptibility of Mycobacterium tuberculosis complex in routine clinical microbiology laboratory

Clinical management of tuberculosis (TB) cases in developing countries is hampered by the lack of a simple and effective diagnostic test. Correct diagnosis of TB is needed to improve treatment, reduce transmission, and control development of drug resistance. This study was undertaken to establish microscopic observation for drug susceptibility (MODS) in clinical microbiology routine. Thirty Mycobacterium tuberculosis isolates and four smear positive sputum specimens were tested for susceptibility to isoniazid, rifampicin, ethambutol and streptomycin using MODS. Results were compared to gold standard methods used at a TB reference laboratory. The median turn around time (TAT) was six days for both direct and indirect assays. Results for rifampicin were 100% concordant with the reference laboratory and those of ethambutol, streptomycin and isoniazid were 97%, 94% and 94% concordant, respectively. In all discordant cases MODS categorize the isolates as resistant. Using SYBR Green to detect growth, there was clear increase in fluorescence for cultures of drug-resistant strains when compared to culture of sensitive strains. The discrepancy in these cases can be explained by the fact that in MODS any growth in drug-containing wells is labelled as resistance and can be resolved in using SYBR Green. MODS can therefore, be considered as a reliable and fast method which could be used as routine in Clinical Microbiology Laboratory in a TB endemic area