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Research shows that the expression of all five house keeping genes are up-regulated in the initial phase of bacterial growth but declines by mid-exponential-growth phase. Expression of 16S rRNA gene is lower than all other genes. Data suggest that housekeeping system is dynamic, which adjusts to different growth conditions.

Byline: B.J.A. Rijnders (1), A. Wilmer (1), J. Van Eldere (1), E. Van Wijngaerden (1) Keywords: Intubation Orotracheal Bacteremia Intensive care units Streptococcus Prospective studies Abstract: Objectives: To examine whether urgent orotracheal intubation (OI) can induce bacteremia. To find predictive factors for post-intubation bacteremia. Design: Prospective observational study. Setting: Seventeen-bed medical intensive care unit in a university hospital. Patients: Sixty-eight adult intensive care patients undergoing urgent OI. Measurements and results: Patients in need of OI could be included if no cardiopulmonary resuscitation was performed. A blood culture was taken immediately before, as soon as possible after, and 60 min after intubation. The indication for intubation, ease of intubation, and the antibiotics used before intubation were registered. Six patients (6/68 or 9%) had streptococcal bacteremia immediately (mean 10.8 min) after intubation. No patient (0/62) had streptococcal bacteremia 60 min after intubation (P=0.01). Four of the six patients showing streptococcal bacteremia after intubation were intubated by a second doctor because of difficulties during intubation, whereas this was the case in only 9/62 in those without streptococcal bacteremia (P=0.01). Four of the 13 patients (31%) who needed to be intubated by a second doctor showed transient streptococcal bacteremia. Of the 20 patients not receiving antibiotics at the time of intubation, four (20%) had streptococcal bacteremia compared with 2/47 (4.2%) patients receiving antibiotics (P=0.06). Conclusions: Urgent intubation can cause transient bacteremia with streptococci in a significant proportion of intensive care patients. The observed frequency of bacteremia is higher than previously reported after elective intubation. The difficulty of intubation is probably a predisposing factor. Author Affiliation: (1) Interne Geneeskunde, Universitaire Ziekenhuizen Leuven, Herestraat 49, 3000 Leuven, Belgium Article History: Received Date: 31/07/2000 Accepted Date: 16/11/2000 Article note: Final revision received: 6 November 2000 Electronic Publication

A gram-positive rod bacterium, called HDCA-1, that does not belong to a known genomic species, was isolated from the rat intestinal microflora. It is able to convert the 3alpha,6beta,7beta-trihydroxy bile acid beta-muricholic acid into hydodeoxycholic acid by dehydroxylation of the 7beta-hydroxy group and epimerization of the 6beta-hydroxy group into a 6alpha-hydroxy group. The strain HDCA-1 could not be grown unless a nonconjugated 7-hydroxylated bile acid and an unidentified growth factor produced by a Ruminucoccus productus strain that was also isolated from the intestinal microflora were added to the culture medium.

The conjugation of taurine with cholic acid (CA) increases the 7-alpha-dehydroxylation of taurocholic acid (TCA) in fecal, defined limited fecal, and binary bacterial cultures. The dehydroxylation in fecal and limited fecal cultures is unaffected by free taurine but increases in binary cultures. The reduction of taurine to H2S is necessary for the activity of TCA. The minimal flora necessary for the dehydroxylation is the Bacteroides sp. strain R1 and Clostridium sp. strain 9/1.

Interpretive reading analyses the complete resistance profiles of bacteria to multiple antibiotics and infers the resistance mechanisms present; it aids therapeutic choice and enhances surveillance data. We evaluated the Advanced Expert System (AES), which interprets MICs generated by the VITEK 2. Ten European laboratories tested 42 reference strains and 76-106 of their own strains, representing important resistance genotypes. Interpretive reading by the VITEK 2 AES achieved full agreement with genotype data for 88-89% of strains, with the correct mechanism identified as one of two possibilities for a further 5-6%. Mechanisms inferred with 90% agreement with reference data included methicillin resistance in staphylococci, glycopeptide resistance in enterococci, quinolone resistance in staphylococci and Enterobacteriaceae, AAC(6')-APH(2")-mediated aminoglycoside resistance in Gram-positive cocci, erm-mediated macrolide resistance in pneumococci, extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae and Pseudomonas aeruginosa, and acquired penicillinases in Enterobacteriaceae. VanA, VanB and VanC phenotypes of enterococci were distinguished reliably, and ESBL production was accurately inferred in AmpC-inducible species as well as Escherichia coli and Klebsiella spp. Mechanisms identified, but only as possibilities among several, included IRT-type beta-lactamases and individual aminoglycoside-modifying enzymes in Enterobacteriaceae. Most disagreements with reference data concerned pneumococci found to have high-level penicillin resistance by the VITEK 2 AES but previously determined, phenotypically, to have intermediate resistance. When ESBL production was inferred in E. coli and klebsiellae, the VITEK 2 AES edited susceptible results for cephalosporins (except cefoxitin) to resistant; when an acquired penicillinase was inferred in Enterobacteriaceae, piperacillin results were edited to resistant; and when staphylococci were found methicillin resistant, resistance was reported for all beta-lactams. Further editing may be desirable (e.g. of cephalosporin results for salmonellas inferred to have ESBLs). [ABSTRACT FROM AUTHOR]

Background: Low serum 25-hydroxyvitamin D (25-[OH]D) levels have been associated with lower FEV(1), impaired immunologic control, and increased airway inflammation. Because many patients with chronic obstructive pulmonary disease (COPD) have vitamin D deficiency, effects of vitamin D supplementation may extend beyond preventing osteoporosis.Objective: To explore whether supplementation with high doses of vitamin D could reduce the incidence of COPD exacerbations.Design: Randomized, single-center, double-blind, placebo-controlled trial. (ClinicalTrials.gov registration number: NCT00666367)Setting: University Hospitals Leuven, Leuven, Belgium.Patients: 182 patients with moderate to very severe COPD and a history of recent exacerbations.Intervention: 100,000 IU of vitamin D supplementation or placebo every 4 weeks for 1 year.Measurements: The primary outcome was time to first exacerbation. Secondary outcomes were exacerbation rate, time to first hospitalization, time to second exacerbation, FEV(1), quality of life, and death.Results: Mean serum 25-(OH)D levels increased significantly in the vitamin D group compared with the placebo group (mean between-group difference, 30 ng/mL [95% CI, 27 to 33 ng/mL]; P < 0.001). The median time to first exacerbation did not significantly differ between the groups (hazard ratio, 1.1 [CI, 0.82 to 1.56]; P = 0.41), nor did exacerbation rates, FEV(1), hospitalization, quality of life, and death. However, a post hoc analysis in 30 participants with severe vitamin D deficiency (serum 25-[OH]D levels <10 ng/mL) at baseline showed a significant reduction in exacerbations in the vitamin D group (rate ratio, 0.57 [CI, 0.33 to 0.98]; P = 0.042).Limitation: This was a single-center study with a small sample size.Conclusion: High-dose vitamin D supplementation in a sample of patients with COPD did not reduce the incidence of exacerbations. In participants with severe vitamin D deficiency at baseline, supplementation may reduce exacerbations.Primary Funding Source: Applied Biomedical Research Program, Agency for Innovation by Science and Technology (IWT-TBM). [ABSTRACT FROM AUTHOR]

RATIONALE: Copy number variations of the cluster of beta-defensin genes have been associated with psoriasis and inflammatory bowel disease. Controversy still exists on whether the beta-defensins genes determine susceptibility for chronic obstructive pulmonary disease (COPD). Objectives: We investigated whether genomic copy number variations of the beta-defensin gene cluster have a functional role in airway epithelial cells and associate with the presence of COPD. METHODS: Baseline and inflammatory induced transcript expression of DEFB4 was studied in nasal epithelial cell cultures and its effect on Pseudomonas aeruginosa inhibition was assessed. Subsequently, relevant functional cut-offs for copy numbers were used to explore associations with COPD in two independent case-control studies. MEASUREMENTS AND MAIN RESULTS: Copy number variation in the beta-defensin encoding genes correlated with baseline mRNA DEFB4 expression levels (R(2) = 0.96; P = 0.02), with a plateau effect from five copies or more. Only when higher copy numbers of beta-defensin genes were present, transcription was significantly up-regulated by tumor necrosis factor-alpha (P < 0.0001), which resulted in better antimicrobial activity in vitro. When comparing healthy smokers with COPD patients, a copy number greater than or equal to 5 was associated with increased risk for COPD with an adjusted odds ratio of 1.8 (confidence interval, 1.1-2.8; P = 0.02), which was confirmed by a second independent case-control study. CONCLUSIONS: Genomic copy number variation of beta-defensin encoding genes has a functional role in airway epithelial cells, which may contribute to the pathogenesis of COPD. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To investigate the presence of extended-spectrum beta-lactamases (ESBLs) among Pseudomonas aeruginosa clinical isolates referred to two Belgian reference laboratories. METHODS: Antibiograms were analysed for P. aeruginosa isolates referred between 2004 and 2008. Isolates resistant to ceftazidime (MIC > 8 mg/L) and with a positive double-disc synergy test between ceftazidime and clavulanate were serotyped and screened for the presence of ESBL-encoding genes. Genes encoding metallo-beta-lactamases (bla(MBL)) were sought by PCR in ESBL-producing isolates with positive imipenem/EDTA synergy tests. PFGE of SpeI-digested genomic DNA was used to compare isolates and selected strains were characterized by multilocus sequence typing. RESULTS: Forty-eight (2.2%) of 2150 P. aeruginosa isolates were confirmed as class A ESBL-producing isolates by molecular testing. bla(BEL) and bla(PER) alleles were detected, respectively, in 39 and 10 P. aeruginosa isolates originating from 16 hospitals (two isolates were simultaneously positive for BEL and PER). Fifteen of the isolates were found to co-produce ESBLs and VIM carbapenemases. These strains were pan-resistant and remained susceptible only to colistin (MICs

Quantification of Bdellovibrio-and-like organisms (BALOs) by microbial culturing has a number of substantial drawbacks. Therefore a quantitative PCR (qPCR) assay was designed for the culture-independent enumeration of the Bdellovibrionaceae. After optimization, the dynamic range of the qPCR assay was assessed, the specificity was evaluated and a comparison with quantitative microbial culturing was made. To evaluate the suitability of the qPCR assay for analysing environmental samples, fresh water samples were investigated by microbial culturing and by the qPCR assay. The results revealed a substantial difference between the two techniques and indicate that most Bdellovibrionaceae cells are left undetected in environmental samples when only current microbial culturing techniques are used. The application of this new technique is therefore likely to confirm the hitherto underestimated sizes and roles of predatory bacterial populations in nature. [ABSTRACT FROM AUTHOR]

Periodontitis is a polymicrobial infectious disease primarily associated with Gram-negative periodontopathogens. Bdellovibrio and like organisms are predatory bacteria that feed on Gram-negative bacteria. This study investigated whether predatory bacteria can attack Aggregatibacter actinomycetemcomitans. Therefore, A. actinomycetemcomitans was challenged with the predator Bdellovibrio bacteriovorus under conditions simulating the oral cavity. The reduction of planktonic A. actinomycetemcomitans was quantified via bacterial culture, and the development of predatory bacteria was monitored with quantitative real-time PCR. The destruction of A. actinomycetemcomitans biofilms by B. bacteriovorus was quantified by crystal violet staining and visualized by scanning electron microscopy. The in vitro results show that B. bacteriovorus can attack, prey on, and kill A. actinomycetemcomitans and suggest a potential for B. bacteriovorus as a living antibiotic for the prevention and treatment of periodontitis. [ABSTRACT FROM AUTHOR]

The complexity of the periodontal microbiota resembles that of the gastro-intestinal tract, where infectious diseases are treatable via probiotics. In the oro-pharyngeal region, probiotic or replacement therapies have shown some benefit in the prevention of dental caries, otitis media, and pharyngitis, but their effectiveness in the treatment of periodontitis is unknown. Therefore, this study addressed the hypothesis that the application of selected beneficial bacteria, as an adjunct to scaling and root planing, would inhibit the periodontopathogen recolonization of periodontal pockets. Analysis of the data showed, in a beagle dog model, that when beneficial bacteria were applied in periodontal pockets adjunctively after root planing, subgingival recolonization of periodontopathogens was delayed and reduced, as was the degree of inflammation, at a clinically significant level. The study confirmed the hypothesis and provides a proof of concept for a guided pocket recolonization (GPR) approach in the treatment of periodontitis. [ABSTRACT FROM AUTHOR]

It is known that beneficial bacteria can suppress the emergence of pathogenic bacteria, particularly in the gastrointestinal tract. This study examined the potential for a similar suppression of Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans colonization of epithelial cells, due to its potential relevance in periodontal diseases. Seven presumed beneficial bacteria were examined for their ability to interfere, exclude, or displace A. actinomycetemcomitans from epithelial cells in vitro. Streptococcus sanguinis, Streptococcus mitis, and Streptococcus salivarius showed prominent inhibitory effects on either A. actinomycetemcomitans recovery or colonization. These results confirmed the hypothesis that bacterial interactions interfere with A. actinomycetemcomitans colonization of epithelial cells in vitro, and demonstrated the potential beneficial effects of S. mitis, S. salivarius, and S. sanguinis. [ABSTRACT FROM AUTHOR]

Adherence of Actinobacillus actinomycetemcomitans to epithelial cells is an important step in periodontal disease pathogenesis. Recent publications describe the subgingival presence of a wide array of viruses [e.g., human cytomegalovirus (hCMV)]. Since viruses can increase cellular susceptibility for bacterial adherence, we investigated whether hCMV renders epithelial cells more prone to adherence by Actinobacillus actinomycetemcomitans. Cultivated HeLa and primary epithelial cells were shown to be semipermissive for hCMV infection, which resulted in increased bacterial adherence. This increase correlated with viral concentrations, was evident in all Actinobacillus actinomycetemcomitans strains examined, and increased during the first 24 hrs, followed by a slight decrease. Immediate early antigen expression was not correlated with the increased adherence of Actinobacillus actinomycetemcomitans. The results confirmed our hypothesis that the adherence of Actinobacillus actinomycetemcomitans is influenced by hCMV in vitro. [ABSTRACT FROM AUTHOR]

Lagrou K, Van Eldere J, Keuleers S, Hagen F, Merckx R, Verhaegen J, Peetermans WE, Boekhout T (University Hospital Leuven, Leuven, Belgium; and Centraalbureau voor Schimmelcultures, CT Utrecht, the Netherlands) Zoonotic transmission ofCryptococcus neoformansfrom a magpie to an immunocompetent patient (Case report).J Intern Med2005;257:385–388.We report a case of cryptococcal meningitis in an immunocompetent female patient with exposure to a pet magpie (Pica pica). Genetically indistinguishable isolates were cultured from the cerebrospinal fluid of the patient and excreta of the bird. Our data strongly suggest zoonotic transmission ofCryptococcus neoformansvar.grubiifrom a magpie to this patient. [ABSTRACT FROM AUTHOR]

Objectives: To determine susceptibility rates and patterns in Pseudomonas aeruginosa strains isolated from nosocomial infections.Methods: Seven hundred and sixteen P. aeruginosa isolates from 40 different hospitals in Belgium and the Grand Duchy of Luxembourg were collected in 1999.Results: Resistance rates varied significantly between hospitals. Of the fluoroquinolones, ciprofloxacin showed least resistance (24%), levofloxacin showed 27.5% resistance and ofloxacin 37.5%. Of the aminoglycosides, amikacin was the most potent antibiotic (10.5% resistance), followed by isepamicin (12%), tobramycin (19.5%) and gentamicin (23.5%). Of the beta-lactam antibiotics, meropenem was the most active (9.5% resistance); piperacillin and piperacillin/tazobactam had, respectively, 24% and 17.5% resistance, ceftazidime 28.5%, cefepime 29.5%, ticarcillin/clavulanic acid 37% and aztreonam 55.5%. MIC distribution curves show the presence of significant subpopulations, with MICs just below breakpoint for many antibiotics.Conclusion: Resistance of P. aeruginosa to penicillins, cephalosporins, fluoroquinolones and aminoglycosides varies between hospitals, but is increasing. [ABSTRACT FROM AUTHOR]

We have investigated the influence of subinhibitory concentrations of erythromycin on the interaction between Streptococcus pneumoniae and human respiratory epithelial cells. Confluent in vitro cell cultures were inoculated with erythromycin-resistant S. pneumoniae and incubated for 24 h. Erythromycin significantly reduced adherence of the pneumococci after 4 h and 24 h: 4.0% ± 0.7% (mean ± s.e.m.) of the pneumococci adhered to the epithelial cells in medium with erythromycin, compared with 7.7% ± 0.8% in medium without erythromycin (P = 0.002) after 4 h, and the corresponding values after 24 h were 24.2% ± 5.3% and 38.4% ± 5.0%, respectively (P = 0.038). Disruption of epithelial integrity by S. pneumoniae, measured as the decrease in transepithelial electrical resistance, was delayed in the presence of erythromycin. Neither addition of erythromycin to the culture medium nor infection of the cell cultures with pneumococci significantly affected secretion of interleukin-8 by the epithelial cells. Addition of erythromycin to a pneumococcal suspension in cell culture medium without respiratory epithelial cells almost completely prevented the release of pneumolysin. We conclude that erythromycin at subinhibitory concentrations reduces the adherence to and disruption of respiratory epithelial cells by S. pneumoniae, possibly by interfering with pneumolysin release. [ABSTRACT FROM PUBLISHER]

Describes the presence of multiple coagulase-negative staphylococci clones in a patient with prosthetic heart valves, which was probably caused by genetic variability in the infecting strain. Genome macrorestriction and amplified fragment-length polymorphism analyses of Staphylococcus epidermidis strains; Changes in antibiotic susceptibility during an infection; Distinction between resistant and susceptible clones.