Wednesday, April 10, 2013
I have not been well as soon as I am I will again be posting 04/10/13
I have not been well as soon as I am I will again be posting 04/10/13
# posted by Pat O'Connor @ 8:23 AM
Sunday, March 10, 2013
Next Generation Sequencing Reveals the Expression of a Unique miRNA Profile in Response to a Gram-Positive Bacterial Infection.
Next Generation Sequencing Reveals the Expression of a Unique miRNA Profile in Response to a Gram-Positive Bacterial Infection.
2013
Source
Animal and Bioscience Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, County Meath, Ireland ; School of Biochemistry and Immunology, Trinity College, Dublin, Ireland.
Abstract
MicroRNAs (miRNAs) are short, non-coding RNAs, which post-transcriptionally regulate gene expression and are proposed to play a key role in the regulation of innate and adaptive immunity. Here, we report a next generation sequencing (NGS) approach profiling the expression of miRNAs in primary bovine mammary epithelial cells (BMEs) at 1, 2, 4 and 6 hours post-infection with , a causative agent of bovine mastitis. Analysing over 450 million sequencing reads, we found that 20% of the approximately 1,300 currently known bovine miRNAs are expressed in unchallenged BMEs. We also identified the expression of more than 20 potentially novel bovine miRNAs. There is, however, a significant dynamic range in the expression of known miRNAs. The top 10 highly expressed miRNAs account for >80% of all aligned reads, with the remaining miRNAs showing much lower expression. Twenty-one miRNAs were identified as significantly differentially expressed post-infectionwith . Several of these miRNAs have characterised roles in the immune systems of other species. This miRNA response to the Gram-positive is markedly different, however, to lipopolysaccharide (LPS) induced miRNA expression. Of 145 miRNAs identified in the literature as being LPS responsive, only 9 were also differentially expressed in response to . Computational analysis has also revealed that the predicted target genes of miRNAs, which are down-regulated in BMEs following infection, are statistically enriched for roles in innate immunity. This suggests that miRNAs, which potentially act as central regulators of gene expression responses to a Gram-positive bacterial infection, may significantly regulate the sentinel capacity of mammary epithelial cells to mobilise the innate immune system.
Labels: Gram-Positive Bacterial Infection, lipopolysaccharide, miRNA Profile, Next Generation Sequencing
# posted by Pat O'Connor @ 9:55 AM
Sunday, February 24, 2013
Candida glabrata Prosthetic Hip Infection.
Candida glabrata Prosthetic Hip Infection.
2012
Bartalesi F, Fallani S, Salomoni E, Marcucci M, Meli M, Pecile P, Cassetta MI, Latella L, Bartoloni A, Novelli A.
Source
Consultant Physician, Infectious and Tropical Diseases Department, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy. bartalesif@aou-careggi.toscana.it.
Abstract
We present a case of a 60-year-old Caucasian woman carrying a 2-year-old hip prosthesis infected by Candida glabrata dose-dependent susceptible to fluconazole and voriconazole. Resection arthroplasty was performed. Six weeks of caspofungin plus liposomal amphotericin combination therapy achieved joint sterilization and allowed a successfully reimplantation arthroplasty. In addition we review 9 cases of C. glabrata prosthetic joint infection described to date in the literature.
Labels: arthroplasty, Candida glabrata, caspofungin, Infection, liposomal amphotericin, Prosthetic Hip
# posted by Pat O'Connor @ 8:32 AM
Wednesday, February 13, 2013
Evaluation of diagnostic value of procalcitonin as a marker of neonatal bacterial infections.
Evaluation of diagnostic value of procalcitonin as a marker of neonatal bacterial infections.
2012
Source
Pathology department, Hamadan University of Medical Sciences, Hamadan, Iran.
Abstract
KEYWORDS: Infection, Newborn, Predictive Value of Tests, Procalcitonin, Sensitivity, Specificity
OBJECTIVE:
This study tried to assess sensitivity, specificity, positive and negative predictive value of procalcitonin for diagnosis of neonatal bacterial infections.
METHODS:
This prospective cross sectional study was carried out during an 18-month period in NICU and neonatal wards of Besat Hospital in Hamedan province, Iran. 39 symptomatic infants with clinical and laboratory findings in favor of bacterialinfection with a positive blood, CSF, and/or supra pubic urine culture entered the study; 32 newborns without any bacterialinfection served as control group. Quantitative procalcitonin level ≥0.5 ng/ml was accepted as pathological. Finally sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were calculated for procalcitonin test.
FINDINGS:
20 blood cultures, 17 urine cultures and 8 CSF cultures were positive. Sensitivity, specificity, PPV and NPV for procalcitonin test was 76.9%, 100%, 100% and 78% respectively. Diagnostic value of procalcitonin test in accordance with blood culture for mentioned items was 85%, 100%, 100% and 91.4% respectively. Its diagnostic value according to urine culture was: sensitivity 70.6%, specificity 100%, PPV 100% and NPV 86.4%, and according to CSF culture was: sensitivity 75%, specificity 100%, PPV 100% and NPV 94.1% respectively.
CONCLUSION:
The results show that the procalcitonin test has high sensitivity, specificity, PPV and NPV for diagnosis of neonatal infections.
Labels: blood cultures, Infection, newborn, Predictive Value of Tests, Procalcitonin, Sensitivity, Specificity, urine cultures
# posted by Pat O'Connor @ 7:57 AM
Role of Bacterial Lipopolysaccharide in Enhancing Host Immune Response to Candida albicans.
Role of Bacterial Lipopolysaccharide in Enhancing Host Immune Response to Candida albicans.
2013
Source
Tissue Engineering and Reparative Dentistry, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Park, Cardiff CF14 4XY, UK.
Abstract
Human infections involving yeast of the genus Candida often occur in the presence of bacteria, and, as such, it is important to understand how these bacteria influence innate host immunity towards Candida. Dectin-1 is a cell receptor of macrophages for Candida albicans recognition. The aim of this study was to examine dectin-1 expression by monocytes after stimulation with bacterial lipopolysaccharide (LPS), followed by heat-killed C. albicans (HKC). Freshly isolated human peripheral blood monocytes (PBMCs) and human monocytes cell line (THP-1) cells expressed low levels of dectin-1. Stimulation with LPS and GM-CSF/IL-4 was found to increase dectin-1 expression in both CD14(+) human PBMC and THP-1 cells. Enhanced dectin-1 expression resulted in increased phagocytosis of Candida. When THP-1 cells were challenged only with HKC, detectable levels of IL-23 were not evident. However, challenge by LPS followed by varying concentrations of HKC resulted in increased IL-23 expression by THP-1 cells in HKC dose-dependent manner. Increased expression of IL-17 by PBMC also occurred after stimulation with Candida and LPS. In conclusion, bacterial LPS induces an enhanced immune response to Candida by immune cells, and this occurs through increasing dectin-1 expression.
Labels: Bacterial Lipopolysaccharide, Candida albicans, Dectin-1, Host Immune Response, human monocytes cell line, peripheral blood monocytes
# posted by Pat O'Connor @ 7:26 AM
Thursday, February 07, 2013
A case of mycoplasma hominis infection on chronic refractory lower leg ulceration caused by livedo vasculopathy
A case of mycoplasma hominis infection on chronic refractory lower leg ulceration caused by livedo vasculopathy
2012
[Article in Japanese]
Source
Clinical Laboratory Department, St. Luke's International Hospital, Chuo-ku, Tokyo 104-8560, Japan. yamaji@luke.or.jp
Abstract
Mycoplasma hominis is a common inhabitant of the human urogenital tract and most frequently causes diseases of the genitourinary tract. Extragenital M. hominis infections are uncommon, with almost all occurring in immunosuppressed persons or those predisposed due to surgery or trauma. We report a case of non surgical, non-traumatic wound infectioncaused by M. hominis. A 28-year-old immunocompetent woman with livedo vasculopathy had an open wound on dorsum of her right foot with signs and symptoms of infection. However, gram staining of the wound swab demonstrated no microorganisms, and initial bacterial cultures did not reveal any microbial growth. After 2 days of culture, minute translucent colonies were appeared and subsequently identified as M. hominis. She was successfully treated with levofloxacin(LVFX). For the patient's being immune-competent, this infection seems to need a substantial bacterial transfer from the inhabitant organ. The transfer is likely mediated by the fluid's drop, for anatomical locations of vagina and the infection site on leg. Namely, the hinder leg infection is suspected to be caused by continual and heavy bacterial exposure originated from the vaginal M. hominis. This clinical case suggests that infections may occur even in normal immunological status if the site is close to, and lacks anatomical barrier from, the M. hominis inhabitant organ. Especially in infection at chronic refractory lower leg ulceration, M. hominis should be considered as a causative organism.
Labels: human urogenital tract, immunocompetent, Infection, levofloxacin, livedo vasculopathy, lower leg ulceration, LVFX, mycoplasma hominis
# posted by Pat O'Connor @ 7:01 AM
Carbon Catabolite Control in Candida albicans: New Wrinkles in Metabolism.
Carbon Catabolite Control in Candida albicans: New Wrinkles in Metabolism.
Feb 2013
Source
Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas, USA.
Abstract
Most microorganisms maintain strict control of nutrient assimilation pathways to ensure that they preferentially use compounds that generate the most energy or are most efficiently catabolized. In doing so, they avoid potentially inefficient conflicts between parallel catabolic and metabolic pathways. The regulation of carbon source utilization in a wide array of bacterial and fungal species involves both transcriptional and posttranscriptional mechanisms, and while the details can vary significantly, carbon catabolite control is widely conserved. In many fungi, the posttranslational aspect (carbon catabolite inactivation [CCI]) involves the ubiquitin-mediated degradation of catabolic enzymes for poor carbon sources when a preferred one (glucose) becomes available.
A recent article presents evidence for a surprising exception to CCI in the fungal pathogen Candida albicans, an organism that makes use of gluconeogenic carbon sources during infection (D. Sandai, Z. Yin, L. Selway, D. Stead, J. Walker, M. D. Leach, I. Bohovych, I. V. Ene, S. Kastora, S. Budge, C. A. Munro, F. C. Odds, N. A. Gow, and A. J. Brown, mBio 3[6]:e00495-12). In vitro, addition of glucose to cells grown in a poor carbon source rapidly represses transcripts encoding gluconeogenic and glyoxylate cycle enzymes, such as phosphoenolpyruvate carboxykinase (Pck1p) and isocitrate lyase (Icl1p), in both C. albicans and Saccharomyces cerevisiae.
Yet, uniquely, the C. albicans proteins persist, permitting parallel assimilation of multiple carbon sources, likely because they lack consensus ubiquitination sites found in the yeast homologs. Indeed, the yeast proteins are rapidly degraded when expressed in C. albicans, indicating a conservation of the machinery needed for CCI. How this surprising metabolic twist contributes to fungal commensalism or pathogenesis remains an open question.
Labels: Candida albicans, Carbon Catabolite, catabolic enzymes, glyoxylate cycle enzymes, Metabolism
# posted by Pat O'Connor @ 6:58 AM
Wednesday, January 30, 2013
Infections Succumbs to Blue Light
Infections Succumbs to Blue Light
January 2013
Blue light can selectively eradicate Pseudomonas aeruginosa infections of the skin and soft tissues, while preserving the outermost layer of skin, according to a proof-of-principle study led by Michael R. Hamblin of the Massachusetts General Hospital, and the Harvard Medical School in Boston. The research is published online ahead of print in the journal Antimicrobial Agents and Chemotherapy.
"Blue light is a potential non-toxic, non-antibiotic approach for treating skin and soft tissue infections, especially those caused by antibiotic resistant pathogens," says Hamblin.
In the study, animal models were infected with P. aeruginosa. All of the animals in the group treated with blue light survived, while in the control, 82 percent (9 out of 11) of the animals died.
Skin and soft tissue infections are the second most common bacterial infections encountered in clinical practice, and represent the most common infection presentation—more than 3 percent—in patients visiting emergency departments, says Hamblin. The prevalence of skin and soft tissue infections among hospitalized patients is 10 percent, with approximately 14.2 million ambulatory care visits every year and an annual associated medical cost of almost $24 billion (equivalent to $76 for every American), says Hamblin.
Treatment of skin and soft tissue infections has been significantly complicated by the explosion of antibiotic resistance, which may bring an end to what medical scientists refer to as the antibiotic era, says Hamblin. "Microbes replicate very rapidly, and a mutation that helps a microbe survive in the presence of an antibiotic drug will quickly predominate throughout the microbial population. Recently, a dangerous new enzyme, NDM-1, that makes some bacteria resistant to almost all antibiotics available has been found in the United States. Many physicians are concerned that several infections soon may be untreatable."
Besides harming public health, antibiotic resistance boosts health care costs. "Treating resistant skin and soft tissue infections often requires the use of more expensive, or more toxic drugs, and can result in longer hospital stays for infected patients," says Hamblin.
Reference: Dai T, Gupta A, et al. 2013. Blue light rescues mice from potentially fatal Pseudomonas aeruginosa burn infection: efficacy, safety, and mechanism of action. Antim. Agents Chemother. Published ahead of print Dec. 21, 2012 ,doi:10.1128/AAC.01652-12)
Labels: Antibiotic resistance, blue light, enzyme, Infection, NDM-1, Pseudomonas aeruginos, skin infections, soft tissue infections, treatment
# posted by Pat O'Connor @ 9:46 AM
Tuesday, January 22, 2013
A systematic review of validation studies of the use of administrative data to identify serious infections.
A systematic review of validation studies of the use of administrative data to identify serious infections.
Jan 2013
Source
Formerly a the Division of Rheumatology, Department of Medicine, University Health Network, and the Division of Health Care and Outcome Research, Toronto Western Research Institute, University of Toronto, Toronto, Ontario, Canada; Division of Rheumatology, Department of Medicine, University of Calgary. cehbarbe@ucalgaryca.
Abstract
OBJECTIVES:
To conduct a systematic review of the literature on the validation of algorithms identifying infections in administrative data for future use in populations with rheumatic diseases.
METHODS:
Medline and Embase were searched using the themes "administrative data" and "infection", between 1950 to October 2012. Inclusion criteria: validation studies of administrative data identifying infections in adult populations. Article quality was assessed using a validated tool.
RESULTS:
5941 articles were identified, 90 articles underwent detailed review and 24 studies were included. The majority (17/24) examined bacterial infections and nine examined opportunistic infections. Eighteen studies were from the United States and all but four studies used ICD-9 codes. Rheumatoid arthritis patients were studied in 6/24. The studies on bacterial infections in general reported highly variable sensitivity and PPV for the diagnosis of infections using administrative data (sensitivity range 4.4-100%, PPV range 21.7-100%). Algorithms to identify opportunistic infections similarly had a highly variable sensitivity (range 20-100%) and PPV (1.3-99%). Thirteen studies compared the diagnostic accuracy of different algorithms which revealed that strategies including comprehensive algorithm using a greater number of diagnostic codes or codes in any position had the highest sensitivity for the diagnosis of infection. Algorithms which incorporated microbiologic or pharmacy data in combination with diagnostic codes had improved PPV for identification of tuberculosis.
CONCLUSION:
Algorithms for identifying infections using administrative data should be selected based on the purpose of the study with careful consideration as to whether a high sensitivity or PPV is required.
Labels: Infections, validation studies
# posted by Pat O'Connor @ 6:16 AM
Tuesday, January 15, 2013
The lymph index: a potential hematological parameter for viral infection.
The lymph index: a potential hematological parameter for viral infection.
Jan 2013
Source
Center of Clinical Laboratory Medicine, the Second Affiliated Hospital of Nantong University, Nantong, 226001, China.
Abstract
OBJECTIVE:
An LH750 hematology analyzer with VCS (volume, conductivity, and light scatter) technology can determine morphologic properties of peripheral leukocytes, known as cell population data (CPD). We have previously demonstrated that the lymphocyte CPD exhibit significant changes in acute hepatitis B virus infection. A simplified lymphocyte CPD, the lymph index, was proposed. We conducted the current study to further evaluate the clinical usefulness of the lymph index, and included patients with various viral infections, as well as those with acute bacterial infections.
METHODS:
Peripheral blood was collected from 72 patients with viral infections, 46 patients with acute bacterial infections, and 204 controls. The lymphocyte CPD included the mean volume (LV) with its standard deviation (LV-SD) and the conductivity (LC). The lymph index was calculated as LV×LV-SD ÷ LC.
RESULTS:
The lymph index was significantly increased in viral infections and only mildly increased in acute bacterial infections compared to controls. Using a lymph index cutoff value of ≥12.92, we achieved 91.67% sensitivity and 97.2% specificity for diagnosing viral infection.
CONCLUSIONS:
The findings may be clinically useful since these morphological parameters are readily obtained by hematology analyzer during automated leukocyte differentials. They are quantitative, objective, and fast. The lymph index could be a potential hematological parameter for viral infection.
Labels: conductivity, CPD, LH750 hematology analyzer, light scatter, lymph index, lymphocyte, VCS, viral infection, volume
# posted by Pat O'Connor @ 7:51 AM
Bacteriophages and their role in food safety.
Bacteriophages and their role in food safety.
2012
Source
Institute for Biotechnology and Bioengineering (IBB), Centre for Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
Abstract
The interest for natural antimicrobial compounds has increased due to alterations in consumer positions towards the use of chemical preservatives in foodstuff and food processing surfaces. Bacteriophages fit in the class of natural antimicrobial and their effectiveness in controlling bacterial pathogens in agro-food industry has led to the development of different phage products already approved by USFDA and USDA. The majority of these products are to be used in farm animals or animal products such as carcasses, meats and also in agricultural and horticultural products. Treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases and ultimately promote safe environments in animal and plant food production, processing, and handling. This is an overview of recent work carried out with phages as tools to promote food safety, starting with a general introduction describing the prevalence of foodborne pathogens and bacteriophages and a more detailed discussion on the use of phage therapy to prevent and treat experimentally induced infections of animals against the most common foodborne pathogens, the use of phages as biocontrol agents in foods, and also their use as biosanitizers of food contact surfaces.
Labels: antimicrobial compounds, bacteriophages, biocontrol, biosanitizers, food safety, USDA, USFDA
# posted by Pat O'Connor @ 7:47 AM
Tuesday, January 08, 2013
Suggested guidelines for using systemic antimicrobials in bacterial skin infections: part 2-- antimicrobial choice, treatment regimens and compliance.
Suggested guidelines for using systemic antimicrobials in bacterial skin infections: part 2-- antimicrobial choice, treatment regimens and compliance.
Jan 2013
Source
Cabinet Vétérinaire, Spa, Belgium.
Abstract
Systemic antimicrobials are critically important in veterinary healthcare, and resistance is a major concern. Antimicrobial stewardship will be important in maintaining clinical efficacy by reducing the development and spread of antimicrobial resistance. Bacterial skin infections are one of the most common reasons for using systemic antimicrobials in dogs and cats. Appropriate management of these infections is, therefore, crucial in any policy for responsible antimicrobial use. The goals of therapy are to confirm that an infection is present, identify the causative bacteria, select the most appropriate antimicrobial, ensure that the infection is treated correctly, and to identify and manage any underlying conditions. This is the second of two articles that provide evidence-led guidelines to help practitioners address these issues. Part 1 discussed the use of clinical signs, cytology and culture in diagnosis. This article will cover the rationale for topical and systemic antimicrobial therapy, including choice of first-, second- and third-line drugs, the dose, duration of therapy, compliance and identification of underlying predisposing conditions. In addition, there is guidance on cases of therapeutic failure and environmental hygiene. These guidelines will help veterinarians avoid the development and propagation of antimicrobial-resistant bacterial strains.
Labels: antimicrobial choice, bacterial skin infections, systemic antimicrobials, treatment regimen
# posted by Pat O'Connor @ 8:07 AM
Suggested guidelines for using systemic antimicrobials in bacterial skin infections: part 1--diagnosis based on clinical presentation, cytology and culture.
Suggested guidelines for using systemic antimicrobials in bacterial skin infections: part 1--diagnosis based on clinical presentation, cytology and culture.
Jan 2013
Source
Cabinet Vétérinaire, Spa, Belgium.
Abstract
Systemic antimicrobials are critically important in veterinary healthcare, and resistance is a major concern. Antimicrobial stewardship will be important in maintaining clinical efficacy by reducing the development and spread of antimicrobial resistance. Bacterial skin infections are one of the most common reasons for using systemic antimicrobials in dogs and cats.
Appropriate management of these infections is, therefore, crucial in any policy for responsible antimicrobial use. The goals of therapy are to confirm that an infection is present, identify the causative bacteria, select the most appropriate antimicrobial, ensure that the infection is treated correctly, and to identify and manage any underlying conditions. This is the first of two articles that will provide evidence-led guidelines to help practitioners address these issues. This article covers diagnosis, including descriptions of the different clinical presentations of surface, superficial and deep bacterial skin infections, how to perform and interpret cytology, and how to best use bacterial culture and sensitivity testing.
Part 2 will discuss therapy, including choice of drug and treatment regimens.
Labels: bacterial skin infections, systemic antimicrobials
# posted by Pat O'Connor @ 8:05 AM
Friday, January 04, 2013
Growth Factor: How Bacterial Infections Persist Through Antibiotics
Growth Factor: How Bacterial Infections Persist Through Antibiotics
By Katherine Harmon | Scientific American
Some strains of nasty bacterial infections, such as MRSA (methicillin-resistant Staphylococcus aureus), come loaded with resistance to antibiotics built right into their genes. But certain infections seem to acquire an ability to persist in the face of drugs that should knock them out--without developing the genetic hallmarks of antibiotic resistance. For decades, researchers have thought this holdout occurred because many antibiotics target cell growth, so even though most of the bacteria were killed by the drug, a select group simply shut down, going into a sort of hibernation, thereby allowing the infection to persist. In other words: if the bacteria aren't growing, they're also not dying.
But a new study suggests that quite the opposite is occurring: some surviving bacteria are actually flourishing and multiplying while under antibiotic attack. The findings were published online January 3 in Science.
"We thought that surviving bacteria made up a fixed population that stopped dividing," Neeraj Dhar, of the Swiss Federal Institute of Technology in Lausanne and study co-author, said in a prepared statement. Instead, a stable overall population was hiding a "very dynamic" colony, he said.
The researchers studied Mycobacterium smegmatis, a species closely related to the bacterium that causes tuberculosis (Mycobacterium tuberculosis), which often resists antibiotic treatment and remains a major health threat in many countries. The traditional analysis of a persistent culture of these bacteria would reveal that the population was not growing, which is what had led scientists to think that the colony had been reduced to non-proliferating "persister cells" that could better ride out the antibiotic attack by laying low. But using time-lapse images taken through a microscope of cells in a microfluidic culture (allowing study of small-scale changes), the researchers saw quite a different story.
"Using microfluidics, we can now observe every bacterium individually, instead of having to count a population," John McKinney, also of the Swiss Federal Institute of Technology, said in a prepared statement. Not only were the surviving cells not playing dead, they were just as likely to be growing as cells that died off.
McKinney and his team observed that even after the introduction of an antibiotic and the death of most bacterial cells, a large percentage of the so-called persister cells continuing to divide--129 of 153 progenitor cells they followed divided at least once in the face of antibiotic treatment. And this cycle of growth, division and death kept up for at least 10 days of exposure to the antibiotic.
The antibiotic was isoniazid (known by the drug names Laniazid and Nydrazid), which has been a common first-line treatment for tuberculosis. This antibiotic becomes an activated bacterium killer when it comes into contact with an enzyme called KatG that the bacteria produces. The enzyme, however, was not produced consistently, the researchers found. Instead, individual cells generated it in seemingly random spurts. So the cells that happened to have had pauses in their KatG production at just the right time were often able to avoid activating the antibiotic--and thus were saved from certain death.
Tuberculosis cells that should have been essentially identical, genetically, showed different propensities for survival, pointing to a possible role of epigenetic differences (such as those in gene expression) in determining cell survival. "This diversity is critical for microbial persistence in fluctuating environments because it ensures that some individuals may survive a lethal stress that would otherwise extinguish the population," the researchers explained in their paper.
Because cell survival does not seem to be tied to permanent genetic change in this case, it means the bacterial colony should remain susceptible to future antibiotic treatment, which could be good news for treating infections. However, given the low level of continued growth and change during exposure to antibiotics, "the bacteria can mutate and thus develop resistance in the presence of the antibiotic," Dhar said.
This discovery now paints a clearer picture of how antibiotic resistance can develop in persistent bacterial infections. With so many individual bacteria reproducing, "some of them can adapt to stressors that they have not previously encountered, thanks to the selection of persistent individuals," McKinney said. Such findings could help inform the creation of more effective antibiotics and perhaps expand to other illnesses, such as the persistence of cancer cells, although the researchers acknowledge that the persistence behavior of other bacterial infections might be quite different.
Nevertheless, the insights offer "a new approach for trying to figure out why some infections are so difficult to eliminate," McKinney said.
News Yahoo
Labels: antibiotics, bacterial infections, Laniazid, methicillin-resistant Staphylococcus aureus, MRSA, Mycobacterium tuberculosis, Nydrazid, persister cells
# posted by Pat O'Connor @ 7:31 AM
Saturday, December 29, 2012
A genomic analysis of Clostridium difficile infections in blunt trauma patients.
A genomic analysis of Clostridium difficile infections in blunt trauma patients.
Jan 2013
Efron PA, Liu H, Lottenberg L, Cuenca AG, Gentile LF, Miggins MV, Bihorac A, Baker HV, Moore FA, Moldawer LL, Ang DN.
Source
From the Departments of Surgery (P.A.E., H.L., L.L., A.G.C., L.F.G., M.V.M., F.A.M., L.L.M., D.N.A.), Anesthesia (A.B.), and Molecular Genetics and Microbiology (H.V.B.), University of Florida, Gainesville, Florida.
Abstract
BACKGROUND:
Evidence demonstrates that susceptibility to Clostridium difficile infection is related to host risk factors as much as bacterial potency. Using blood leukocyte genome-wide expression patterns of severe blunt trauma patients obtained by the National Institute of General Medical Sciences-sponsored Glue Grant Inflammation and the Host Response to Injury, we examined leukocyte genomic profiles of patients with C. difficile infection to determine preinfection and postinfection gene expression changes.
METHODS:
The genomic responses of 21 severe trauma patients were analyzed (5 C. difficile, 16 controls matched for age and severity of injury). After elimination of probe sets whose expression was below baseline or were unchanged, remaining probe sets underwent hierarchical clustering and principal component analysis. Molecular pathways were generated through Ingenuity Pathways Analysis.
RESULTS:
Supervised analysis demonstrated 118 genes whose expression in patients with C. difficile infection varied before and after their infection. Supervised analysis comparing patients with C. difficile infection with matched non-C. difficile patients before infection suggested that the expression of 501 genes were different in the two groups with up to 87% class prediction (p < 0.05). Many of these genes are related to cell-mediated immune responses, signaling, and interaction.
CONCLUSION:
Genomic analysis of severe blunt trauma patients reveals a distinct leukocyte expression profile of C. difficile both before and after infection. We conclude that an association may exist between a severe trauma patient's leukocyte genomic expression profile and subsequent susceptibility to C. difficile infection. Further prospective expression analysis of this C. difficile population may reveal potential therapeutic interventions and allow early identification of C. difficile-susceptible patients.
LEVEL OF EVIDENCE:
Prognostic/diagnostic study, level III.
Labels: bacterial potency, blunt trauma patient, Clostridium difficile, Genomic analysis, Infection
# posted by Pat O'Connor @ 8:48 AM
