Chemotherapy in conjoint aging-tumor systems: some simple models for addressing coupled aging-cancer dynamics

Background In this paper we consider two approaches to examining the complex dynamics of conjoint aging-cancer cellular systems undergoing chemotherapeutic intervention. In particular, we focus on the effect of cells growing conjointly in a culture plate as a precursor to considering the larger multi-dimensional models of such systems. Tumor cell growth is considered from both the logistic and the Gompertzian case, while normal cell growth of fibroblasts (WI-38 human diploid fibroblasts) is considered as logistic only. Results We demonstrate, in a simple approach, how the interdependency of different cell types in a tumor, together with specifications of for treatment, can lead to different evolutionary patterns for normal and tumor cells during a course of therapy. Conclusions These results have significance for understanding appropriate pharmacotherapy for elderly patients who are also undergoing chemotherapy

Modeling the Effects of a Simple Immune System and Immunodeficiency on the Dynamics of Conjointly Growing Tumor and Normal Cells

In this paper, we develop a theoretical contribution towards the understanding of the complex behavior of conjoint tumor-normal cell growth under the influence of immuno-chemotheraputic agents under simple immune system response. In particular, we consider a core model for the interaction of tumor cells with the surrounding normal cells. We then add the effects of a simple immune system, and both immune-suppression factors and immuno-chemotherapeutic agents as well. Through a series of numerical simulations, we illustrate that the interdependency of tumor-normal cells, together with choice of drug and the nature of the immunodeficiency, leads to a variety of interesting patterns in the evolution of both the tumor and the normal cell populations

Drug resistance patterns of bacteria isolated from patients with nosocomial pneumonia at Tehran hospitals during 2009-2011

INTRODUCTION: Nosocomial pneumonia remains an important cause of mortality and morbidity worldwide. Surveillance programs play an important role in the identification of common etiologic agents and local patterns of antimicrobial resistance. METHODOLOGY: In this study we determined the frequency and antimicrobial susceptibility of pathogens isolated from patients with nosocomial pneumonia during 2009 to 2011. RESULTS: A total of 642 bacteria were isolated from 516 suspected samples. Acinetobacter baumannii (21.1%, n = 136), was the commonest isolated pathogen followed by Pseudomonas aeruginosa (17.4%, n = 112), Staphylococcus aureus (15.8%, n = 102) and enterococci (8.4% n = 54). The most effective therapeutic agents against A. baumannii were polymyxin B (95.5% susceptible), ceftriaxone/tazobactam (72% susceptible) and levofloxacin (52.9% susceptible). Polymixin B (89.2% susceptible), ceftriaxone/tazobactam (89.2% susceptible) and piperacillin-tazobactam (80.3% susceptible) were found to be the most active agents against P. aeruginosa. Extended-spectrum beta-lactamases were detected among isolates of K. pneumoniae (45.4%) and E. coli (20.3%). Overall, the prevalence of methicillin-resistant S. aureus and vancomycin resistant enterococci were 80.4% and 40.7% respectively. Linezolid was found to be the most active antibiotic against these pathogens. The etiology of 50% of the nosocomial infection cases was polymicrobial. CONCLUSIONS: The combination of ceftriaxone/tazobactam seems to be beneficial agent against multidrug-resistant Gram-negative bacilli isolated form respiratory tract infections. The results of our study can be used for guiding appropriate empiric therapy in this geographic region

Development of a modified DNA extraction method for pulsed-field gel electrophoresis analysis of Staphylococcus aureus and enterococci without using lysostaphin

A modified pulsed-field gel electrophoresis (PFGE) protocol was developed and applied to clinical isolates of Staphylococcus aureus and enterococci to reduce the cost of using lysostaphin. This protocol reduces the expenses of PFGE typing of S. aureus and enterococci as it removes the use of lysostaphin during the spheroplast formation from these bacteria

Development of a new DNA extraction protocol for PFGE typing of Mycobacterium tuberculosis complex.

A modified pulsed-field gel electrophoresis (PFGE) protocol was developed and applied to clinical isolates of Mycobacterium tuberculosis complex to reduce the cost of using lyticase. This protocol reduces the expense of PFGE typing of Mycobacterium tuberculosis complex as it removes the use of lyticase during the spheroplast formation from these bacteri

The inhibitory effect of a Lactobacillus acidophilus derived biosurfactant on Serratia marcescens biofilm formation

Objective(s): Serratia marcescens is one of the nosocomial pathogen. The ability to form biofilm is an important feature in the pathogenesis of S. marcescens. The aim of this study was to determine the anti�adhesive properties of a biosurfactant isolated from Lactobacillus acidophilus ATCC 4356, on S. marcescens strains. Materials and Methods: Lactobacillus acidophilus ATCC 4356, was selected as a probiotic strain to produce biosurfactant. Anti�adhesive activities was determined by pre�coating and co� incubating methods in 96�well culture plates. Results: The FTIR analysis of derived biosurfactant revealed the composition as protein component. Because of the release of such biosurfactants, L. acidophilus was able to interfere with the adhesion and biofilm formation of the S. marcescens strains. In co� incubation method this biosurfactant in 2.5 mg/ml concentration showed anti�adhesive activity against all tested strains of S. marcescens (P<0.05). Conclusion: Our results show anti�adhesive properties of L. acidophilus biosurfactant will be useful against microorganisms responsible for infections in the urinary, vaginal and gastrointestinal tracts, as well as skin, making it a suitable alternative to conventional antibiotics. © 2015, Mashhad University of Medical Sciences. All rights reserved

Detection and quantification of Streptococcus pneumoniae from Iranian patients with pneumonia and individual carriers by real time PCR

The aim of this study was to develop a real time polymerase chain reaction (PCR) for quantitative detection of Streptococcus pneumoniae from clinical respiratory specimens. Initially, 184 respiratory specimens from patients with community acquired pneumonia (CAP) (n = 129) and 55 cases with hospital associated pneumonia (HAP) were bacteriologically investigated. To check the colonization status among the healthy individuals, 32 preschool and 31 adults were screened in parallel. All specimens were cultured on selective culture media to isolate S. pneumoniae, Legionella spp. and Mycoplasma spp. A 166 bp fragment corresponding to cbp A gene of S. pneumoniae was amplified from clinical specimens using Taqman probe real time PCR. Culture showed 14, but real time PCR showed 15 specimens as being positive for S. pneumoniae. The specificity and sensitivity of real time PCR was 99.14% and 100 respectively. Co-infections of S. pneumoniae with Legionella pneumophila, Chlamydophila pneumoniae, Mycoplasma pneumoniae and Staphylococcus aureus were observed in 5 cases (35.72%). S. pneumoniae was counted &lt;103 cfu/ml from the co-infected cases. Using real time PCR, a cutoff of 103cfu/ml is introduced to differentiate colonization from infection in respiratory tract. This is the first report on the prevalence CAP with S. pneumoniae in Iran (12.40%).Key words: Streptococcus pneumoniae, community acquired pneumonia (CAP), real time polymerase chain reaction (PCR), choline binding protein A (cbp A)

Rapid, cost-effective, sensitive and quantitative detection of Acinetobacter baumannii from pneumonia patients

BACKGROUND AND OBJECTIVES: Pneumonia with Acinetobacter baumannii has a major therapeutic problem in health care settings. Decision to initiate correct antibiotic therapy requires rapid identification and quantification of organism. The aim of this study was to develop a rapid and sensitive method for direct detection of A. baumannii from respiratory specimens. MATERIALS AND METHODS: A Taqman real time PCR based on the sequence of bla(oxa-51) was designed and used for direct detection of A. baumannii from 361 respiratory specimens of patients with pneumonia. All specimens were checked by conventional bacteriology in parallel. RESULTS: The new real time PCR could detect less than 200 cfu per ml of bacteria in specimens. There was agreement between the results of real time PCR and culture (Kappa value 1.0, p value<0.001). The sensitivity, specificity and predictive values of real time PCR were 100%. The prevalence of A. baumannii in pneumonia patients was 10.53 % (n=38). Poly-microbial infections were detected in 65.71% of specimens. CONCLUSION: Acinetobacter baumannii is the third causative agent in nosocomial pneumonia after Pseudomonas aeroginosa (16%) and Staphylococcus aureus (13%) at Tehran hospitals. We recommend that 104 CFU be the threshold for definition of infection with A. baumannii using real time PCR