Bacterial infections

It is estimated that approximately one billion people are at risk of infection with obligate intracellular bacteria, but little is known about the underlying mechanisms that govern their life cycles. The difficulty in studying Chlamydia spp., Coxiella spp., Rickettsia spp., Anaplasma spp., Ehrlichia spp. and Orientia spp. is, in part, due to their genetic intractability. Recently, genetic tools have been developed; however, optimizing the genomic manipulation of obligate intracellular bacteria remains challenging. In this Review, we describe the progress in, as well as the constraints that hinder, the systematic development of a genetic toolbox for obligate intracellular bacteria. We highlight how the use of genetically manipulated pathogens has facilitated a better understanding of microbial pathogenesis and immunity, and how the engineering of obligate intracellular bacteria could enable the discovery of novel signalling circuits in host-pathogen interactions.

Diabetes mellitus is a chronic disease with serious health consequences. The association between diabetes and periodontal disease is well documented. However, the progression and healing of endodontic infections in diabetic patients has not been adequately studied. In this review, diabetes mellitus is explored as a potential modulating factor of endodontic pathosis. Recent data on the relationship between the clinical presentation of pulpal and periradicular disease, as well as the outcome of endodontic treatment in diabetic and nondiabetic patients, are presented. Diabetics who present for endodontic treatment, particularly those with periradicular pathosis, may have increased perioperative symptoms. Cases with preoperative periradicular lesions are less likely to be determined successful two years or longer postoperatively if the patient reports a history of diabetes. Studies examining the pathogenesis of periradicular lesions in mouse models with uncontrolled type 1 diabetes sugg...

Polymerase chain reaction electrospray ionization mass spectrometry (PCR/ESI-MS) was tested for its ability to accurately identify a blinded panel of 156 diverse bacterial isolates, mostly human and/or animal pathogens. Here, 142/156 (91%) isolates were correctly identified to the genus level and 115/156 (74%) were correctly identified to the species level. Only 9% were misidentified. This study shows that multilocus PCR/ESI-MS has the potential to be a useful technique for identifying a broad range of bacteria.

Broad-range amplification of bacterial DNA from clinical specimens has proved useful for the diagnosis of various bacterial infections, especially during antimicrobial treatment of the patient. Optimal sample processing protocols for diagnostic broad-range bacterial PCR should release DNA from an array of target organisms with equal efficiencies and wash out inhibitory factors from various sample types without introducing bacterial DNA contamination to the amplification reaction. In the present study, two physical cell wall disintegration methods, bead beating and sonication, for enhanced detection of organisms with difficult-to-lyse cell walls were studied. The analytical sensitivities of several commercially available DNA purification kits, which were used with and without additional cell disintegration steps, were compared by using dilution series of model bacteria. Selected purification methods were used to process routine clinical specimens in parallel with the standard phenol-...

Gastrointestinal motility disorders are often present in diabetic patients. Even if this problem has been attributed to autonomic neuropathy, the pathophysiological mechanisms responsible are not completely defined. Aim of our study was to evaluate the effect of eradication of small-intestine bacterial overgrowth on oro-cecal transit time in diabetic patients in order to identify a possible role of bacterial overgrowth on dysmotility. We selected among 74 diabetic patients who underwent H2-lactulose breath test, 21 subjects (13M, 8F, mean age 43.7 years, 11 with type 1 and 10 with type 2 diabetes) affected by bacterial overgrowth and delayed oro-cecal transit time and with normal cardiovascular autonomic test. Patients were treated with rifaximin and underwent a control breath test. Data were analyzed using paired-data t-test. Three patients still showed bacterial overgrowth, 5 persistent delayed transit time without bacterial overgrowth; 13 patients (62%) showed a significant (P &l...

To date there are no clear criteria to determine whether a microbe is susceptible to biocides or not. As a starting point for distinguishing between wild-type and resistant organisms, we set out to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) distributions for four common biocides; triclosan, benzalkonium chloride, chlorhexidine and sodium hypochlorite for 3319 clinical isolates, with a particular focus on Staphylococcus aureus (N = 1635) and Salmonella spp. (N = 901) but also including Escherichia coli (N = 368), Candida albicans (N = 200), Klebsiella pneumoniae (N = 60), Enterobacter spp. (N = 54), Enterococcus faecium (N = 53), and Enterococcus faecalis (N = 56). From these data epidemiological cut-off values (ECOFFs) are proposed. As would be expected, MBCs were higher than MICs for all biocides. In most cases both values followed a normal distribution. Bimodal distributions, indicating the existence of biocide resistant subpo...

Background Suppression of immune system in treated cancer patients may lead to secondary infections that obviate the need of antibiotics. In the present study, an attempt was made to understand the occurrence of secondary infections in immuno-suppressed patients along with herbal control of these infections with the following objectives to: (a) isolate the microbial species from the treated oral cancer patients along with the estimation of absolute neutrophile counts of patients (b) assess the in vitro antimicrobial activity medicinal plants against the above clinical isolates. Methods Blood and oral swab cultures were taken from 40 oral cancer patients undergoing treatment in the radiotherapy unit of Regional Cancer Institute, Pt. B.D.S. Health University, Rohtak, Haryana. Clinical isolates were identified by following general microbiological, staining and biochemical methods. The absolute neutrophile counts were done by following the standard methods. The medicinal plants selected...

We reviewed all episodes of peritonitis associated with exit site and/or tunnel infection (n = 87; rate, 0.1/yr; 13% of all peritonitis episodes) occurring from 1979 to 1995. The exit site or tunnel infection was diagnosed at the time or shortly after the patient presented with peritonitis in 66% of the episodes. In the other one third the exit site

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) was established to harmonise clinical antimicrobial breakpoints and to define breakpoints for new agents in Europe. Data from the European Antimicrobial Resistance Surveillance Network (EARS-Net) external quality assessment (EQA) exercises from 2009 to 2012, from the United Kingdom External Quality Assessment Scheme (UK NEQAS) from November 2009 to March 2013 and data collected by EUCAST through a questionnaire in the first quarter of 2013 were analysed to investigate implementation of EUCAST guidelines in Europe. A rapid change to use of EUCAST breakpoints was observed over time. Figures for implementation of EUCAST breakpoints at the end of the studied period were 61.2% from EARSNet data and 73.2% from UK NEQAS data. Responses to the EUCAST questionnaire indicated that EUCAST breakpoints were used by over 50% of laboratories in 18 countries, by 10 to 50% of laboratories in eight countries and by less than 10% ...

In a young evolving science, there are always more questions than answers. That is also the situation in the emerging field of Probiotics, and this was made very clear at the International Probiotics Workshop in Amsterdam. In the report of this workshop, we present a selection of the most urgent questions in the field of probiotics. In addition, we propose a few strategies for the future of probiotics research. During the workshop, 120 experts--from disciplines including Human Nutrition, Gastroenterology, Nutritional Therapy, Cell Biology, Microbiology and Immunology--discussed new views on microbe-host interactions and the role of probiotics in prevention and alleviation of gastro-intestinal, atopic and auto-immune diseases. There is a general consensus among the experts that administering defined strains can help in preventing and curing gut flora related diseases: the first clinical trials show a promising role for probiotics. But the system is very complex, and most underlying m...

Brain abscesses are rare but potentially deadly complications of odontogenic infections. This phenomenon has been described mainly in the form of case reports, as large-scale studies are difficult to perform. We compiled a total of 60 previously published cases of such a complication to investigate the predisposing factors, microbiology, and clinical outcomes of intracranial abscesses of odontogenic origin. A systematic review of the literature using the PubMed database was performed. Men accounted for 82.1% of cases, and the mean age was 42.1years. Caries with periapical involvement and periodontitis were the two most common intra-oral sources, and wisdom tooth extraction was the most common preceding dental procedure. In 56.4% of cases, there were obvious signs of dental disease prior to development of intracranial infection. Commonly implicated microorganisms included Streptococcus viridans (especially the anginosus group), Actinomyces, Peptostreptococcus, Prevotella, Fusobacteri...

BACKGROUND Symptoms of bacterial sinusitis overlap with viral sinusitis, and it is difficult to distinguish between the two conditions based only on a clinical examination. Uncertain diagnosis results in the significant overuse of antibiotics, which is considered to be one of the most important reasons for development of bacterial resistance to antibiotics. A raised C-reactive protein (CRP) level is an indicator of bacterial infection and the CRP rapid test has been shown to be useful for the diagnosis of bacterial sinusitis in general practice. AIMS To examine whether general practitioners (GPs) who use the CRP rapid test in their practice have a lower antibiotic prescribing rate for sinusitis than GPs who do not use the test. DESIGN OF STUDY Observational design. SETTING General practice in Denmark. METHOD A group of GPs registered all contacts (n = 17 792) with patients who had respiratory tract infections during a 3-week period between 1 November 2001 and 31 January 2002. GPs wh...

Patients undergoing intensive chemotherapy for acute myeloid leukemia are at high risk for bacterial infections during therapy-related neutropenia. However, the use of specific antibiotic regimens for prophylaxis in afebrile neutropenic acute myeloid leukemia patients is controversial. This was a retrospective evaluation of 172 acute myeloid leukemia patients who received 322 courses of myelosuppressive chemotherapy and had an expected duration of neutropenia of >7 days. The patients were allocated to antibiotic prophylaxis groups and treated with colistin or ciprofloxacin through 2 different hematological services at our hospital as available. The infection rate was reduced from 88.6% to 74.2% through antibiotic prophylaxis (vs. without prophylaxis, p=0.04). A comparison of both antibiotic drugs revealed a trend towards fewer infections associated with ciprofloxacin prophylaxis (69.2% vs. 79.5% in the colistin group, p=0.07), as determined by univariate analysis. This result was...

BACKGROUND: An enhanced bacterial detection system (Pall eBDS) was developed that distinguishes itself from its predecessor (Pall BDS) by removal of the platelet (PLT)-retaining filter allowing for optimal bacterial transfer, modification of the culture tablet to reduce the confounding effects of respiring PLTs while enhancing bacterial growth, and facilitation of nutrients and gas exchange by agitating the sample pouch during incubation at 35°C. The objective was to evaluate the performance of the new eBDS.STUDY DESIGN AND METHODS: Leukoreduced whole blood–derived PLT concentrates (LR-PCs) and LR single-donor PLTs (LR-SDPs) were inoculated with 1 to 15 colony-forming units (CFUs) of bacteria per mL in studies of each of 10 bacterial species associated with fatal transfusion-transmitted bacterial infection. Immediately after inoculation and after 24 hours of storage at 22°C, samples of inoculated LR-PCs were aseptically transferred into the eBDS pouches. Pouches were then incubated for 24 hours at 35°C with agitation and oxygen concentration was then measured.RESULTS: Median inoculation levels ranged from 5 to 13 CFUs per mL for each species studied. No significant differences in oxygen concentration were found when comparing LR-PCs with LR-SDPs. When sampling occurred from the PLTs 24 hours after inoculation, all 280 cases (24-33 replicates of each species) were detected as contaminated by the device (100% sensitivity). No false-positives were obtained with 713 uninoculated PLT units.CONCLUSIONS: The eBDS demonstrated improved detection sensitivity in the range of 1 to 15 CFUs per mL with no observed false-positives compared to the original BDS (detection range 100 to 500 CFUs/mL) with no false-positives.