Assessment of Bacterial Antibiotic Resistance Transfer in the Gut

We assessed horizontal gene transfer between bacteria in the gastrointestinal (GI) tract. During the last decades, the emergence of antibiotic resistant strains and treatment failures of bacterial infections have increased the public awareness of antibiotic usage. The use of broad spectrum antibiotics creates a selective pressure on the bacterial flora, thus increasing the emergence of multiresistant bacteria, which results in a vicious circle of treatments and emergence of new antibiotic resistant bacteria. The human gastrointestinal tract is a massive reservoir of bacteria with a potential for both receiving and transferring antibiotic resistance genes. The increased use of fermented food products and probiotics, as food supplements and health promoting products containing massive amounts of bacteria acting as either donors and/or recipients of antibiotic resistance genes in the human GI tract, also contributes to the emergence of antibiotic resistant strains. This paper deals with the assessment of antibiotic resistance gene transfer occurring in the gut

Complete Genome Sequence of a Multidrug-Resistant <i>Klebsiella pneumoniae</i> Environmental Isolate from Zanzibar, Tanzania, Harboring Novel Insertion Elements and Two <i>bla</i>CTX-M-15 Genes

Here, we report the annotated whole-genome sequence of Klebsiella pneumoniae strain KP_3b, isolated in Zanzibar, Tanzania, from plastic litter. The strain is extended-spectrum β-lactamase (ESBL) producing and multidrug resistant, encoding 17 resistance genes, most of which are located on a 230,544-bp plasmid. The isolate contains two copies of the bla(CTX-M-15) gene and novel insertion elements

Measurements of AMPs in stratum corneum of atopic dermatitis and healthy skin-tape stripping technique

Abstract Decreased levels of antimicrobial peptides (AMPs) in atopic dermatitis (AD) have previously been reported and have been linked to the increased susceptibility to skin infections found in AD patients. This study intents to identify AMPs: hBD-2, hBD-3, RNase7, psoriasin and LL-37 in AD patients and healthy controls, and determine concentrations in consecutive depths of the outer most skin layers. Tape stripping was used on lesional and non-lesional skin. From each skin site, 35 consecutive tape strips were collected and pooled in groups of 5. Commercially available ELISA kits were used to determine AMP concentration in stratum corneum samples. hBD-2, hBD-3, RNase7 and psoriasin were identified in stratum corneum samples. hBD-3-level was markedly higher in AD non-lesional skin compared to healthy controls, and a similar trend was observed for RNase7. Most AMPs were distributed evenly through 35 tape strips, implying a homogeneous distribution of antimicrobial defense in the outer most skin layers. The findings indicate that AD patients may not suffer from a general baseline deficiency in AMPs, and that the innate immune defense is present throughout the stratum corneum, both insights of importance for understanding the role of AMPs in AD

Detection of Legionella by quantitative-polymerase chain reaction (qPCR) for monitoring and risk assessment

<p>Abstract</p> <p>Background</p> <p>Culture and quantitative polymerase chain reaction (qPCR) assays for the detection of <it>Legionella </it>were compared on samples from a residential area before and after two interventions. A total of 84 samples were collected from shower hoses and taps as first flush samples and at constant temperature. Samples were grouped according to the origin of the sample, a) circulation water b) water from empty apartments c) water from shower hoses. The aims were to investigate the usefulness of qPCR compared to culture for monitoring remedial actions for elimination of <it>Legionella </it>bacteria and as a tool for risk assessment.</p> <p>Results</p> <p>In water collected from the apartments <it>Legionella </it>spp were detected by qPCR in the concentration range from LOQ to 9.6*10⁵GU/L while <it>L. pneumophila </it>were detected in a range from LOQ to 6.8*10⁵GU/L. By culturing, the legionellae were detected in the range from below detection limit (> 10 CFU/L) to 1.6*10⁶CFU/L. In circulating water and in first flush water from shower hoses, culture and qPCR showed the same tendencies. The overall correlation between the bacteria number detected by culture and the two developed qPCR assays (<it>L</it>. spp and <it>L. pneumophila</it>) was relatively poor (r²= 0.31 for culture and <it>Legionella </it>spp. assay, r²= 0.20 for culture and <it>L. pneumophila </it>assay).</p> <p>Conclusion</p> <p>Detection by qPCR was suitable for monitoring changes in the concentration of <it>Legionella </it>but the precise determination of bacteria is difficult. Risk assessment by qPCR only on samples without any background information regarding treatment, timing, etc is dubious. However, the rapid detection by qPCR of high concentrations of <it>Legionella </it>- especially <it>Legionella pneumophila </it>- is valuable as an indicator of risk, although it may be false positive compared to culture results. On the other hand, the detection of a low number of bacteria by qPCR is a strong indication for the absence of risk.</p

Expression of Escherichia coli F-18 Type 1 Fimbriae in the Streptomycin-Treated Mouse Large Intestine

Escherichia coli F-18, isolated from the feces of a healthy human, makes type 1 fimbriae and is an excellent colonizer of the streptomycin-treated mouse large intestine. Recently, it was shown that the inability to produce type 1 fimbriae had no effect on the ability of E. coli F-18 to colonize the streptomycin-treated mouse large intestine, suggesting the possibility that E. coli F-18 does not express type 1 fimbriae in vivo. However, we show here that E. coli F-18 does express type 1 fimbriae in mouse cecal mucus in vivo and, in fact, appears to express substantially more type 1 fimbriae in cecal mucus in vivo than in L broth in vitro

Microbial diversity in fecal samples depends on DNA extraction method: easyMag DNA extraction compared to QIAamp DNA stool mini kit extraction

BACKGROUND: There are challenges, when extracting bacterial DNA from specimens for molecular diagnostics, since fecal samples also contain DNA from human cells and many different substances derived from food, cell residues and medication that can inhibit downstream PCR. The purpose of the study was to evaluate two different DNA extraction methods in order to choose the most efficient method for studying intestinal bacterial diversity using Denaturing Gradient Gel Electrophoresis (DGGE). FINDINGS: In this study, a semi-automatic DNA extraction system (easyMag®, BioMérieux, Marcy I’Etoile, France) and a manual one (QIAamp DNA Stool Mini Kit, Qiagen, Hilden, Germany) were tested on stool samples collected from 3 patients with Inflammatory Bowel disease (IBD) and 5 healthy individuals. DNA extracts obtained by the QIAamp DNA Stool Mini Kit yield a higher amount of DNA compared to DNA extracts obtained by easyMag® from the same fecal samples. Furthermore, DNA extracts obtained using easyMag® seemed to contain inhibitory compounds, since in order to perform a successful PCR-analysis, the sample should be diluted at least 10 times. DGGE performed on PCR from DNA extracted by QIAamp DNA Stool Mini Kit DNA was very successful. CONCLUSION: QIAamp DNA Stool Mini Kit DNA extracts are optimal for DGGE runs and this extraction method yields a higher amount of DNA compared to easyMag®