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Volume 57,
Issue 1,
2008
Volume 57, Issue 1, 2008
- Review
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Comparison of utility of blood cultures from intravascular catheters and peripheral veins: a systematic review and decision analysis
More LessBlood cultures are sometimes obtained from intravascular catheters for convenience. However, there is controversy regarding this practice. The authors compared the diagnostic test characteristics of blood cultures obtained from intravascular catheters and peripheral veins. Relevant studies for inclusion in this review were identified through PubMed (January 1970–October 2005) and the Cochrane Central Register of Controlled Trials. Studies that reported clear definitions of true bacteraemia were included in the analysis. Two reviewers independently extracted the data. Six studies were included in the analysis, providing data for 2677 pairs of blood cultures obtained from an intravascular catheter and a peripheral venipuncture. A culture obtained from an intravascular catheter was found to be a diagnostic test for bacteraemia with better sensitivity (OR 1.85, 95 % CI 1.14–2.99, fixed effects model) and better negative predictive value (almost with statistical significance) (OR 1.55, 95 % CI 0.999−2.39, fixed effects model) but with less specificity (OR 0.33, 95 % CI 0.18–0.59, random effects model) and lower positive predictive value (OR 0.41, 95 % CI 0.23–0.76, random effects model) compared to a culture taken by peripheral venipuncture. In a group of 1000 patients, eight additional patients with true bacteraemia would be identified and 59 falsely diagnosed as having bacteraemia by a blood culture obtained from an intravascular catheter compared to results of the peripheral blood culture. Given the consequences of undertreating patients with bacteraemia, the authors believe that, based on the available evidence, at least one blood culture should be obtained from the intravascular catheter.
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- Pathogenicity And Virulence
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Association between Helicobacter pylori VacA antigens and gastric cancer depends on the detection method used: immunoblot versus neutralization of the vacuolating activity of VacA
More LessThere are inconsistent findings on the association between Helicobacter pylori anti-VacA antibodies and gastric cancer (GC) risk. The lack of optimally sensitive and specific methods to detect anti-VacA antibodies may partly be responsible for this discrepancy. The aim of this study was to compare the association between GC and the presence of anti-VacA antibodies using two different detection methods. A secondary analysis of sera collected in a hospital-based case–control study in three geographical areas of Mexico was performed. Anti-VacA antibodies were determined by a neutralization assay and an immunoblot assay in serum samples of 203 histologically confirmed GC cases and 430 age- and sex-matched controls. H. pylori IgG status was determined by immunoblotting and H. pylori CagA status data was available for this study. Unconditional logistic regression models were used to estimate the association between anti-VacA antibodies and GC by histological type (diffuse and intestinal). Anti-VacA seroprevalence was higher using neutralization compared with immunoblotting: 68.5 vs 44.3 % for cases and 60.5 vs 44.2 % for controls. A significant association between anti-VacA antibodies and diffuse GC was found using neutralization [odds ratio (OR)=1.69, 95 % CI 1.08–2.66], but the association did not remain significant after adjusting for CagA status (OR 1.37, 95 % CI 0.81–2.32). No association between anti-VacA antibodies and GC was found when using immunoblotting. Thus, the association between anti-VacA antibodies and GC partly depends on the detection method used. These results do not support an independent role for VacA in GC risk in the presence of CagA seropositivity and strengthen the importance of CagA as a potential risk factor for GC.
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Evaluation of in vitro virulence characteristics of the genus Pandoraea in lung epithelial cells
Pandoraea species are emerging opportunistic pathogens capable of causing chronic lung infections in cystic fibrosis patients. This study examined the interactions of 17 Pandoraea isolates from the five identified species (Pandoraea apista, Pandoraea norimbergensis, Pandoraea pulmonicula, Pandoraea sputorum and Pandoraea pnomenusa) plus two Pandoraea genomospecies isolates with lung epithelial cells and their ability to form biofilms in vitro. Only three isolates showed an ability to invade A549 lung epithelial cells, and only one isolate was able to form biofilms. In contrast, all isolates triggered a pronounced pro-inflammatory response, with elevation of both interleukin (IL)-6 (two- to 19-fold) and IL-8 (10- to 50-fold) above that observed for a control strain of Escherichia coli. This property is likely to be a major factor in the pathogenesis of the genus.
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Community-wide transmission of a strain of Mycobacterium tuberculosis that causes reduced lung pathology in mice
Since 1992, Mycobacterium tuberculosis strain PG004 has been responsible for a large outbreak of tuberculosis in one northern Californian community. There are no epidemiological or host factors to explain this outbreak. PG004 was therefore analysed for biological characteristics that might explain its widespread distribution. BABL/c mice were infected intravenously with PG004, non-PG004 M. tuberculosis strains CCC20 and CCC23 isolated from patients in the same community, and the laboratory strain H37Rv. The susceptibility of PG004 to reactive nitrogen intermediates (RNIs) was compared with that of H37Rv. Because of the reported association of phenolic glycolipid production with mouse virulence, a junction sequence in the polyketide synthase gene cluster (pks15/1) was compared among strains. It was found that the most virulent strain, based on mouse mortality, was not the outbreak strain PG004, but the non-outbreak strain CCC20. This strain had an intact pks15/1 sequence identical to that of another non-outbreak strain, CCC23, which caused death in only one out of ten mice in 300 days of follow-up. The outbreak strain PG004 had a frameshift mutation in the pks15/1 sequence identical to the sequence of H37Rv, and it was no more resistant to RNIs than H37Rv. The most distinguishing feature of PG004 was its failure to produce well-organized, coalescing granulomas in mouse lungs. The lack of organized granulomas and reduced pathology may prevent restriction of PG004 in the lungs and allow it to spread into alveolar air spaces and escape the host to transmit to others. Humans with reduced lung pathology may remain undiagnosed and untreated in the community longer than those with severe disease. The over-representation of an M. tuberculosis strain in a community, therefore, may be more associated with strains that cause reduced rather than severe lung pathology.
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- Host Response
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Parenteral immunization of mice with a genetically inactivated pertussis toxin DNA vaccine induces cell-mediated immunity and protection
More LessThe immunogenicity and protective efficacy of a DNA vaccine encoding a genetically inactivated S1 domain of pertussis toxin was evaluated using a murine respiratory challenge model of Bordetella pertussis infection. It was found that mice immunized via the intramuscular route elicited a purely cell-mediated immune response to the DNA vaccine, with high levels of gamma interferon (IFN-γ) and interleukin (IL)-2 detected in the S1-stimulated splenocyte supernatants and no serum IgG. Despite the lack of an antibody response, the lungs of DNA-immunized mice were cleared of B. pertussis at a significantly faster rate compared with mock-immunized mice following an aerosol challenge. To gauge the true potential of this S1 DNA vaccine, the immune response and protective efficacy of the commercial diphtheria–tetanus–acellular pertussis (DTaP) vaccine were included as the gold standard. Immunization with DTaP elicited a typically strong T-helper (Th)2-polarized immune response with significantly higher titres of serum IgG than in the DNA vaccine group, but a relatively weak Th1 response with low levels of IFN-γ and IL-2 detected in the supernatants of antigen-stimulated splenocytes. DTaP-immunized mice cleared the aerosol challenge more efficiently than DNA-immunized mice, with no detectable pathogen after day 7 post-challenge.
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- Diagnostics, Typing And Identification
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Diagnostic value of DNA and (1→3)-β-d-glucan detection in serum and bronchoalveolar lavage of mice experimentally infected with Fusarium oxysporum
More LessA sensitive and highly specific nested PCR (nPCR) protocol was developed for the specific detection of Fusarium oxysporum DNA in clinical specimens. The diagnostic value of F. oxysporum-specific DNA and (1→3)-β-d-glucan (BDG) detection was subsequently evaluated in serum and bronchoalveolar lavage (BAL) specimens of mice infected intravenously with F. oxysporum conidia. Mice were sacrificed in groups of six daily up to day 8 and then on days 11 and 14. The F. oxysporum-specific DNA and BDG in serum and BAL specimens were detected using nPCR and a Fungitell kit, respectively. Cultures of lung homogenate of all of the infected animals yielded F. oxysporum and the fungus was also observed in KOH/Calcofluor mounts of 67 % of the tissues. The BDG (cut-off value 80 pg ml−1) and nPCR sensitivity in BAL and serum specimens was 15 and 98 %, and 92 and 75 %, respectively. Combined detection of F. oxysporum DNA and BDG in serum enhanced the sensitivity to 98 %. However, the kinetics of the two markers were slightly different. Whilst BDG positivity in serum remained high throughout the infection period, nPCR positivity declined slowly. The data obtained in this study suggest that combined detection of BDG and DNA in serum offers a sensitive and specific diagnostic approach for invasive Fusarium infection.
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A hospital-wide study of the impact of introducing a personal data assistant-augmented blood culture round
More LessBlood culture is the cornerstone of an established aetiological diagnosis of septicaemia. The automated blood culture systems used for this purpose have changed little in the last decade, and the clinical value of results depends on a variety of factors, including pre- and post-analytical variables. Growing scepticism over the value of blood culture results and pressure for the introduction of molecular detection systems have prompted a critical path analysis of pre-, peri- and post-analytical stages in the generation of positive blood culture results. The impact of a positive blood culture was studied in a teaching hospital for 12 months before and 12 months after the introduction of a microbiologist's blood culture round. Active culture reporting via a blood culture ward round was supported by a personal data assistant database of contemporaneous laboratory and clinical data. Hospital occupancy and death register records were subsequently obtained through the State Government data linkage project. There was no evidence that faster laboratory generation of positive blood culture results, faster reporting of results or direct clinical interaction with the patient's primary medical team reduced the risk of death in hospital. However, there was a threefold increase in the rate of death in hospital following a 1 day delay in collection of blood cultures after hospital admission (P=0.0010). The overall duration of hospital stay for patients with a positive blood culture fell by 2.5 days compared with the previous 12 month period (P=0.0003). The interval between the initial positive culture result and patient discharge fell by 2 days (P=0.0010). This difference was attributed to shorter overall admissions and shorter intervals between positive cultures containing Gram-positive cocci and subsequent patient discharge (P=0.0018). An increased mortality rate from community-acquired bacteraemic infections was associated with delayed culture collection, but not with a prolonged laboratory processing interval. Thus, the speed of conventional blood culture analysis and the form of clinical reporting have little direct effect on the clinical outcome of bacteraemia, but may contribute to a reduction in the length of hospital admission. Introduction of molecular identification tests, such as multiplex PCR methods, at the Gram-stain stage of blood culture is unlikely to affect the rate of death in hospital, but may reduce the length of hospital admission.
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Development of a loop-mediated isothermal amplification method for diagnosing Pneumocystis pneumonia
Loop-mediated isothermal amplification (LAMP) is a novel, rapid nucleic acid amplification method with high specificity and sensitivity under isothermal conditions. In this study a LAMP assay for diagnosing Pneumocystis pneumonia (PCP) was developed. Oligonucleotide primers specific for Pneumocystis species were designed corresponding to 18S rRNA gene sequences. The assay, performed for 30 min at 61 °C, was capable of detecting 50 copies per tube (2×103 copies ml−1) in 30 min and did not show cross-reactivity to other species of fungi, including the genera Candida, Aspergillus and Cryptococcus. A total of 21 of 24 clinical specimens (sputum and bronchoalveolar lavage fluid) from patients with suspected PCP tested positive using the LAMP assay by real-time fluorescence detection. The results of the LAMP reaction were also observed by real-time turbidity detection and end-point visual turbidity or fluorescence detection. With real-time fluorescence detection, melting curves of the products were effective at distinguishing specific amplification from non-specific amplification or self-amplification. Visual detection was also possible as a rapid and easy assay using only a heat block and a black light.
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Molecular typing of Japanese Escherichia coli O157 : H7 isolates from clinical specimens by multilocus variable-number tandem repeat analysis and PFGE
The multilocus variable-number tandem repeat analysis (MLVA) method to target eight variable-number tandem repeat loci, based on agarose gel electrophoresis separation of multiplexed PCR products, and the PFGE method were applied to clinical isolates of Escherichia coli O157 : H7 with the aim of comparing their performance as methods of typing this bacterium. Using MLVA, a total of 57 isolates from patients in Shizuoka prefecture, Japan, were divided into 20 types and classified into 23 PFGE types. Twenty-four isolates from four sporadic infections, four household contact infections and one outbreak that occurred in central parts of Shizuoka prefecture during August to November in 2005 were shown to be the same MLVA type, and most of the isolates had identical PFGE banding patterns, suggesting the diffuse outbreak in these parts of Japan. Thus, there was a good correlation between MLVA types and PFGE types, with both methods displaying broadly similar discriminatory powers. However, the MLVA typing proved to be a much easier and more rapid method for the analysis of E. coli O157 : H7 strain relatedness to identify transmission routes. Hence, our MLVA method would be a suitable technique for routine typing in many laboratories, including public health agencies, and even in hospitals.
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Specific detection and differentiation of Ochrobactrum anthropi, Ochrobactrum intermedium and Brucella spp. by a multi-primer PCR that targets the recA gene
Ochrobactrum anthropi, Ochrobactrum intermedium and Brucella spp. are phenotypically and genetically closely related pathogens that may cause disease with similar clinical presentation. Consequently, difficulties in their identification and differentiation have been reported. In this study, a sensitive recA gene-based multi-primer single-target PCR (MP-ST-PCR) was developed that allowed the specific detection and differentiation of these clinically relevant pathogens. The specificity of the assay was evaluated using a representative panel of 50 O. anthropi and 16 O. intermedium strains and the type strains of all Brucella spp. Detection limits for purified DNA from O. anthropi, O. intermedium and Brucella melitensis were 100, 10 and 100 fg, respectively. Brucella DNA was also successfully detected in various clinical specimens from a human patient with culture-proven brucellosis and from a Brucella-infected sheep and its aborted fetuses. The sensitivity of the MP-ST-PCR was comparable to that of an evaluated in-house Brucella real-time PCR assay. The developed assay closes a diagnostic gap and provides a simple but robust tool for the sensitive detection and correct identification of O. anthropi, O. intermedium and Brucella spp.
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- Antimicrobial Agents And Chemotherapy
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Identification and characterization of a vancomycin-resistant Staphylococcus aureus isolated from Kolkata (South Asia)
More LessA pathogenic vancomycin-resistant Staphylococcus aureus (VRSA) isolate (MIC ≥64 μg ml−1) was obtained from a Kolkata hospital in June 2005. Species identification was confirmed by Gram staining, standard biochemical tests and PCR amplification of the nuc gene, which encodes the thermostable nuclease that is highly specific for S. aureus. The VRSA isolate was also resistant to beta-lactams (amoxicillin, ampicillin, cefepime, cefotaxime, cefuroxime, cephalexin and meticillin), chloramphenicol, streptomycin, macrolides (erythromycin and roxithromycin), clindamycin, rifampicin and trimethoprim-sulfamethoxazole. However, the isolate was susceptible to gentamicin (an aminoglycoside) and ciprofloxacin (a fluoroquinolone). The resistance to vancomycin was inducible in vitro, because the MIC of vancomycin increased from 64 μg ml−1 initially to 1024 μg ml−1 during culture of this VRSA strain in the presence of vancomycin. The VRSA isolate contained a large plasmid (∼53.4 kb) and four small plasmids of ∼6, 5.5, 5.1 and 1.5 kb. The large plasmid of ∼53.4 kb harboured the vancomycin-resistance genes vanHAX, which was confirmed by PCR amplification using the same plasmid as template and, separately, primers specific for the 2.61 kb vanHAX gene cluster, vanH (969 bp), vanA (1032 bp) and vanX (609 bp). The VRSA isolate was also positive for mecA. Vancomycin resistance was successfully transferred from this VRSA donor to a vancomycin-sensitive recipient S. aureus clinical isolate by a broth mating procedure. The MIC of vancomycin for the transconjugant was 32 μg ml−1, as against 2 μg ml−1 for the parent strain. Nucleotide sequencing of the PCR product showed partial homology with van genes of an enterococcal transposon Tn1546-like element. This is believed to be the first Indian S. aureus isolate that has been shown to be phenotypically vancomycin-resistant, presumably due to a vanHAX analogue.
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A cross-reactive neisserial antigen encoded by the NMB0035 locus shows high sequence conservation but variable surface accessibility
The meningococcal NMB0035 locus encodes a 47 kDa outer-membrane protein that is highly conserved antigenically, and is able to induce antibodies during infection and bactericidal responses in vitro. This study analysed the surface exposure of this protein using specific antibodies in flow cytometry assays and determined its nucleotide sequence in 33 Neisseria strains. Genomic analyses revealed no significant differences in the nucleotide or amino acid sequences, but flow cytometry showed that surface accessibility was highly variable among the strains. These results suggest that masking by and/or association with lipo-oligosaccharides or other membrane molecules can be crucial for antigen accessibility, which must be thoroughly analysed in new vaccine candidates.
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- Oral Microbiology
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Analysis of the antimicrobial activity of local anaesthetics used for dental analgesia
More LessSeven local anaesthetics and their active anaesthetic components [Ultracaine D-S (articaine hydrochloride), Carbostesin (bupivacaine hydrochloride), Scandicaine (mepivacaine hydrochloride), Xylonest (prilocaine hydrochloride), Xylocaine (lidocaine hydrochloride), Hostacaine (butanilicaine phosphate) and Novocaine (procaine hydrochloride)] were tested for their antimicrobial activity against 311 bacterial strains from 52 different species and 14 Candida albicans strains. The tested pathogens were members of the oral flora, and partly members of the skin and intestinal flora. Additionally, the antimicrobial activity of methyl-4-hydroxybenzoate, sodium disulfite, adrenaline hydrogen tartrate and adrenaline (the preservative and vasoconstrictive components of the anaesthetics) was tested. For determination of MIC and minimal bactericidal concentration (MBC), the agar dilution method using Wilkins–Chalgren agar was applied. The trade preparation Ultracaine D-S showed the most prominent antimicrobial activity with regard to both MIC and MBC. Ultracaine D-S and its active substance, articaine hydrochloride, showed similar MIC values, suggesting that the antimicrobial activity is mainly caused by the anaesthetic component. Novocaine showed the lowest antimicrobial activity and did not inhibit 35 of the species tested. The MIC values of all local anaesthetics were between 0.25 and 16 mg ml−1. The routinely applied concentration of Ultracaine D-S was roughly four times higher, and of Hostacaine was two times higher, than the MBC values for the tested bacteria, whereas for the other anaesthetics, the MBC values were not reached or exceeded with the concentrations used. The MIC range of the preservatives was 0.5–1.0 mg ml−1 for methyl-4-hydroxybenzoate and 0.2–0.5 mg ml−1 for sodium disulfite. The articaine MIC values were two to three serial dilution steps lower, and the butanilicaine MIC values one to two serial dilution steps lower, than the MIC of the preservatives. The mepivacaine mean MIC values were slightly lower for Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis and Staphylococcus aureus, but higher for Streptococcus intermedius, compared with the preservative methyl-4-hydroxybenzoate. The same result was found with Streptococcus intermedius and lidocaine. Screening of 20 MIC values of 4 pure anaesthetic substances and the corresponding preservative found 2/20 instances where the MICs of the preservatives against 5 representative species (67 strains) were lower, indicating that the antimicrobial effect was mainly due to the preservative, but 18/20 results where the pure anaesthetic component showed greater antimicrobial effects compared with the preservative. The in vitro results for Carbostesin, Scandicaine and especially for Novocaine indicate that a local disinfection should be done prior to injection of the anaesthetics. Due to the results obtained with nosocomial strains (Escherichia coli, S. aureus and Pseudomonas), disinfection of the mucous membranes should be performed routinely in immunocompromised patients, regardless of the anaesthetic used.
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Occurrence of staphylococci in the oral cavities of healthy adults and nasal–oral trafficking of the bacteria
More LessTo investigate a possible peroral route of infective endocarditis (IE), the occurrence of staphylococci in the oral cavity was examined using saliva and supragingival plaque specimens from 56 systemically and periodontally healthy adults aged 22–43 years old (27.1±5.3). Nine Staphylococcus species and 334 isolates were identified. In saliva, the total occurrence rate was 83.9 % and the total number of bacteria was 102–104 c.f.u. ml−1. Staphylococcus aureus was the most frequent species (46.4 %), followed by Staphylococcus epidermidis (41.1 %) and others (Staphylococcus hominis, Staphylococcus warneri, Staphylococcus intermedius, Staphylococcus capitis, Staphylococcus haemolyticus, Staphylococcus lugdunensis and Staphylococcus gallinarum, isolation frequencies ranging in order from 12.5 to 1.8 %). A similar isolation tendency was observed in supragingival plaque, with a total occurrence rate of 73.2 % and amounts of bacteria ranging from 102 to 105 c.f.u. g−1. Four common Staphylococcus species (S. aureus, S. epidermidis, S. lugdunensis and S. hominis) were isolated from nasal swab samples taken from the oral staphylococci-positive subjects. Genotyping of all 18 combinations of oral- and nasal-derived isolates by PFGE indicated that identical clones or close relatives were commonly distributed in these two cavities. Since the provision of micro-organisms from the nasal cavity was shown and occurrence rates in the oral cavity were adequate, these results suggest a possible peroral route of staphylococcal IE, as in cases of viridans streptococcal IE.
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- Models Of Infection
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Oral administration of a catalase-producing Lactococcus lactis can prevent a chemically induced colon cancer in mice
Reactive oxygen species, such as hydrogen peroxide (H2O2), are involved in various aspects of tumour development. Decreasing their levels can therefore be a promising approach for colon cancer prevention. The objective of this study was to evaluate the effect of catalase-producing Lactococcus lactis on the prevention of an experimental murine 1,2-dimethylhydrazine (DMH)-induced colon cancer. DMH-treated BALB/c mice received either a catalase-producing L. lactis strain or the isogenic non-catalase-producing strain as a control, whereas other untreated mice did not receive bacterial supplementation. Catalase activity and H2O2 levels in intestinal fluids and blood samples were measured, and changes in the histology of the large intestines during tumour progression were evaluated. The catalase-producing L. lactis strain used in this study was able to slightly increase catalase activities in DMH-treated mice (1.19±0.08 U ml−1) and reduce H2O2 levels (3.4±1.1 μM) compared to (i) animals that received the non-catalase-producing strain (1.00±0.09 U ml−1, 9.0±0.8 μM), and (ii) those that did not receive bacterial supplementation (1.06±0.07 U ml−1, 10.0±1.1 μM). Using the histopathological grading scale of chemically induced colorectal cancer, animals that received the catalase-producing L. lactis had a significantly lesser extent of colonic damage and inflammation (2.0±0.4) compared to animals that received the non-catalase-producing L. lactis (4.0±0.3) or those that did not receive bacterial supplementation (4.7±0.5). The catalase-producing L. lactis strain used in this study was able to prevent tumour appearance in an experimental DMH-induced colon cancer model.
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Development of a novel ex vivo insect model for studying virulence determinants of Escherichia coli K1
More LessA key step in Escherichia coli K1 meningitis is the crossing of the blood-brain barrier by the bacteria in order to gain entry into the central nervous system (CNS). In this study, a novel ex vivo model to study E. coli K1 invasion of the CNS is described that uses the African migratory locust, Locusta migratoria. By injecting bacteria into isolated locust head capsules, it was demonstrated that E. coli K1 invade the locust brain within 2 h in numbers depending on the concentration of bacteria injected. Using several mutants derived from K1, it was shown that outer-membrane protein A is a critical bacterial determinant required for the E. coli K1 invasion. The isogenic gene-deletion mutants, ΔfimH, Δcnf1, ΔneuDB and a rough LPS mutant showed significantly reduced invasion of locust brain. This novel model for the study of E. coli K1 pathogenesis offers several advantages over existing mammalian models in relation to its relative ease of use, cost-effectiveness and ethical acceptability.
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- Human And Animal Microbial Ecology
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Differential clustering of bowel biopsy-associated bacterial profiles of specimens collected in Mexico and Canada: what do these profiles represent?
Bowel commensals appear to be an important source of antigens that drive the chronic immune inflammation characteristic of Crohn's disease and ulcerative colitis [inflammatory bowel diseases (IBD)]. Biopsy-associated bacteria are assumed to be particularly relevant in bacteriological investigations of IBD because they are assumed to be located on the mucosal surface and hence close to immunological cells. This investigation analysed the bacterial collections associated with bowel biopsies, aspirates of residual fluid after bowel cleansing and faeces from IBD patients and non-IBD subjects in Edmonton, Canada, and Mexico City, Mexico. Temporal temperature gradient gel electrophoresis of 16S rRNA gene sequences produced profiles of the bacterial collections and their similarities were compared. Similarity analysis showed that the profiles did not cluster according to disease status, but that Canadian and Mexican profiles could be differentiated by this method. Comparison of biopsy, aspirate and faecal samples obtained from the same subject showed that, on average, the profiles were highly similar. Therefore, biopsy-associated bacteria are likely to represent, at least in part, contaminants from the fluid, which resembles a faecal solution, that pools in the bowel after cleansing prior to endoscopy.
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- Case Reports
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Infection by Panton–Valentine leukocidin-producing Staphylococcus aureus clinically mimicking Lemierre's syndrome
More LessLemierre's syndrome is an oropharyngeal infection which leads to severe septic thrombophlebitis of the internal jugular vein and metastatic abscesses of the lungs and other organs. It is usually caused by Fusobacterium necrophorum, a Gram-negative obligate anaerobe. An unusual case of Panton–Valentine leukocidin (PVL)-producing Staphylococcus aureus infection masquerading as Lemierre's syndrome is reported here. A 32-year-old fit and otherwise healthy male presented on Christmas morning with a boil on his left cheek for 2 days and generalized rash for 3 h. His general condition began to worsen, he developed facial swelling and loss of vision in the left eye and was transferred to the intensive care unit. His treatment was taken over by team of specialists and further investigations revealed thrombophlebitis of the left internal jugular vein and cavernous sinus thrombosis with multiple brain infarcts and lung abscesses. His condition remained critical with multiple cranial nerve involvement despite being on broad-spectrum antibiotics. Blood cultures grew S. aureus which was producing PVL toxin. He improved gradually over several weeks. He underwent intensive physiotherapy and made a good recovery. Although a rare entity, it is important to consider Lemierre's syndrome in septic patients who present with rapidly worsening symptoms.
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Upper and lower urinary tract infection caused by Klebsiella pneumoniae serotype K2 and CTX-M-15 β-lactamase-producing serotype K1: a case report and characterization of serum killing resistance
More LessCTX-M-15 β-lactamase-producing Klebsiella pneumoniae serotype K1 was isolated from a patient with fatal upper urinary tract infection (UTI) complicated by sepsis caused by K. pneumoniae serotype K2. Transfer of a CTX-M-15 β-lactamase plasmid from the K1 to the K2 strain was observed. However, plasmid acquisition by the K2 strain did not occur in vivo, suggesting that the K1 strain might not have contributed directly to the upper UTI. In addition, effects of K serotypes and plasmid acquisition on K. pneumoniae serum resistance were examined.
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Citrobacter freundii peritonitis and tunnel infection in a patient on continuous ambulatory peritoneal dialysis
More LessThe clinical course of a patient on continuous ambulatory peritoneal dialysis who developed peritonitis and tunnel infection due to an unusual pathogen, Citrobacter freundii, is described. The patient did not respond well to antibiogram-based therapy (intravenous meropenem and intraperitoneal gentamicin) and removal of the catheter was required.
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Volumes and issues
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Volume 72 (2022 - 2023)
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