Confluence of Prefix-Constrained Rewrite Systems

Prefix-constrained rewriting is a strict extension of context-sensitive rewriting. We study the confluence of prefix-constrained rewrite systems, which are composed of rules of the form L: l -> r where L is a regular string language that defines the allowed rewritable positions. The usual notion of Knuth-Bendix\u27s critical pair needs to be extended using regular string languages, and the convergence of all critical pairs is not enough to ensure local confluence. Thanks to an additional restriction we get local confluence, and then confluence for terminating systems, which makes the word problem decidable. Moreover we present an extended Knuth-Bendix completion procedure, to transform a non-confluent prefix-constrained rewrite system into a confluent one

Evaluation of Phenotypic Variations in the Antibiotics Sensitivity of Escherichia Coli by Repeated Exposure

Enterobacteriaceae, in particular Escherichia coli, are habitual residents of the gastrointestinal tract, capable of causing a large number of infections. The MIC varies according to the bacterial strains and the antibiotics used, hence the need to carry out antibiotic sensitivity tests. The objective of this study is to evaluate the behavior of Escherichia coli after repeated exposure to the same antibiotic to demonstrate a possible correlation between excessive intake of antibiotics and bacterial resistance. A prospective and descriptive study was carried out in the Laboratory of Microbiology of Fundamental and Applied Biochemistry (Faculty of Sciences Antananarivo) during the month of November 2019. The strains studied were the reference strain Escherichia coli ATCC 25922 provided by the Laboratory and two clinical strains from the Microbiology Laboratory of the Joseph Ravoahangy Andrianavalona University Hospital Center (CHU JRA) Antananarivo. Repeated exposure to Tobramycin and Ofloxacin of these strains were performed. The results of our study showed that most E. coli is exposed to the antibiotic, the more it develops resistance. The evolution of E. coli\u27s sensitivity is different in the presence of Tobramycin with MICs up to 4 times the starting value while in the presence of Ofloxacin, the MIC increases to 125 times the initial value. This difference may be due to the different target of the antibiotic which causes the bacteria to develop variable mechanisms to escape it. Key words: E. coli - MIC - antibiotics - repeated exposur

A STUDY ON RECTAL CARRIAGE OF MULTIRESISTANT GRAM-NEGATIVE BACILLI IN CHILDREN ATTENDING PEDIATRIC HOSPITAL AMBOHIMIANDRA, MADAGASCAR

Introduction: Gram-negative bacilli are often responsible for rectal colonization in children. These bacilli normally sensitive to third generation cephalosporins (3GC) have acquired disturbing antibiotic resistance in recent years, hence the interest of our study. The aims are to monitor the epidemiological evolution resistance of Enterobacteriaceae with antibiotics in particular β-lactams, estimate the prevalence of enterobacteria responsible for rectal colonization and their resistance to 3GC. Material and methods: This is a descriptive prospective study of Enterobacteriaceae in children attending Ambohimiandra Hospital for a period of 3 months (from 01 August to 31 October 2015). We have done a rectal swab of all the children whom we have parental consent. The samples were processed at the Laboratory of Medical Biology Faravohitra. The parameters studied are the antecedent of therapy antibiotic, notion of recent hospitalization and the results of microbiological examinations. Results: Of the 55 bacteriological samples obtained, 39 strains of Enterobacteriaceae were isolated, Escherichia coli (n = 12), Enterobacter cloacae (n = 13), Citrobacter spp (n = 1), Salmonella spp. (N = 5) and Shigella spp (n = 2), Proteus mirabilis (n = 1). Six isolated strains (50%) of Escherichia coli showed resistance to ceftriaxone, of which 4 (33.33%) produced ESBL. Conclusion: Gram-negative bacilli responsible for colonization of the digestive tract have several resistances to β-lactams, in particular 3GC, by the production of enzymes (Expanded spectrum beta-lactamase or ESBL and cephalosporinase or CASE) which hydrolyze these antibiotics. Measures to combat the spread of these phenomena resistance must be implemented in the Malagasy community to limit them. KEYWORDS: Rectal porous; Gram negative bacillus; ESBL; Multiresistence

Evaluation of Phenotypic Variations in the Antibiotics Sensitivity of Escherichia Coli by Repeated Exposure

Enterobacteriaceae, in particular Escherichia coli, are habitual residents of the gastrointestinal tract, capable of causing a large number of infections. The MIC varies according to the bacterial strains and the antibiotics used, hence the need to carry out antibiotic sensitivity tests. The objective of this study is to evaluate the behavior of Escherichia coli after repeated exposure to the same antibiotic to demonstrate a possible correlation between excessive intake of antibiotics and bacterial resistance. A prospective and descriptive study was carried out in the Laboratory of Microbiology of Fundamental and Applied Biochemistry (Faculty of Sciences Antananarivo) during the month of November 2019. The strains studied were the reference strain Escherichia coli ATCC 25922 provided by the Laboratory and two clinical strains from the Microbiology Laboratory of the Joseph Ravoahangy Andrianavalona University Hospital Center (CHU JRA) Antananarivo. Repeated exposure to Tobramycin and Ofloxacin of these strains were performed. The results of our study showed that most E. coli is exposed to the antibiotic, the more it develops resistance. The evolution of E. coli's sensitivity is different in the presence of Tobramycin with MICs up to 4 times the starting value while in the presence of Ofloxacin, the MIC increases to 125 times the initial value. This difference may be due to the different target of the antibiotic which causes the bacteria to develop variable mechanisms to escape it. Key words: E. coli - MIC - antibiotics - repeated exposur

Status of resistance to antimicrobial agents of Staphylococcus aureus strains at the laboratory of microbiology of the HU-JRA Antananarivo

Introduction: On contact of antibiotics, S. aureus has gradually acquired multiple antibiotic resistances, including the methicillin (MRSA) and without lose its virulence. The aim of the present study was to report the evolution of resistance of S. aureus to different common antibiotics and to determine the antibiotics active against MRSA.Materials and methods: This is a retrospective and descriptive study for 10 years from January 2005 to December 2014 at the Laboratory of Microbiology of the HU-JRA Antananarivo, the biggest academic hospital located in the capital of Madagascar. All demands for standard bacteriological examination were registered in the laboratory for various bacteriological exams or from samples taken from hospitalized patients and we included all positive cultures for S. aureus. The variables selected and used for the study were community or nosocomial sources of patients and results of susceptibility testing.Results: A total of 906 results from 282 (31.12%) community-acquired and 624 (68.88%) nosocomial infections were studied an average of 100±25strains by year of study. Overall, the prevalence of MRSA was 13.83% (39 of 282 isolates)for community-acquired strains, and 15.70% (98 of 624) for nosocomial infections (p> 0.05)with a total of 29.53%. Resistance rate to trimethoprim-sulfamethoxazole was significantly higher in nosocomial infection than in community-acquired. No significant difference was observed in other antibiotics. Of the 137 MRSA, except vancomycin, fusidic acid is the antibiotic that worked the most in 114 cases (83.21%) followed by gentamicin in 96 cases (70.07%). Apart from ciprofloxacin and tetracycline that we have noticed an increase in resistance rates in 2012 and 2013, almost all antibiotics tested have a stable rate of resistance.Conclusion: The antibiotics tested showed extremely high rates of resistance and that the problem of antibiotic resistance in S. aureus is effective in our center.Keywords: Resistance -antibiotics- S. aureus - HU-JRA Antananariv

SEROPREVALENCE OF HIV, HBV, HCV, SYPHILIS AMONG DONORS OF BLOOD AT THE NATIONAL CENTER OF BLOOD TRANSFUSION ANTANANARIVO IN 2014

Introduction: Currently, routine screening for HIV, hepatitis B and C and syphilis is done in most blood banks in the world. Methods: We conducted a prospective descriptive study at the National Blood Transfusion Center (CNTS) Antananarivo for a period of 7 months from January to July 2014, which aims to assess the socio-clinical factors accompanying ineligibility of blood products and to determine the seroprevalence of HIV, hepatitis B, C and syphilis of the blood donors who have spent at CNTS HU JRA Antananarivo during this period. All donors who have abnormal results of microbiological examinations were included. The parameters used and studied were age, sex, marital status, blood and results microbiological examinations for HIV, hepatitis B, C, and syphilis. The prevalence of blood donors who presented a serological abnormality is 3.95% with a predominance of donors with hepatitis B (72.93%) followed by syphilis (18.29%) of the hepatitis C (6.95%) and HIV (1.80%) and a predominance of young people. Conclusion: At the CNTS Antananarivo, the HBV is the main definitive reason for exclusion of these donors. This high prevalence is a real public health problem for the country\u27s health authorities. The search for maximum safety in blood transfusion through firstly a better selection of blood donors by implementing a policy of strong loyalty and other early diagnosis of major diseases transmissible by blood and likely to infect the recipient. KEYWORDS: Antananarivo; Blood donor; Microbiology; Seroprevalence

SEROPREVALENCE OF HIV, HBV, HCV, SYPHILIS AMONG DONORS OF BLOOD AT THE NATIONAL CENTER OF BLOOD TRANSFUSION ANTANANARIVO IN 2014

Introduction: Currently, routine screening for HIV, hepatitis B and C and syphilis is done in most blood banks in the world. Methods: We conducted a prospective descriptive study at the National Blood Transfusion Center (CNTS) Antananarivo for a period of 7 months from January to July 2014, which aims to assess the socio-clinical factors accompanying ineligibility of blood products and to determine the seroprevalence of HIV, hepatitis B, C and syphilis of the blood donors who have spent at CNTS HU JRA Antananarivo during this period. All donors who have abnormal results of microbiological examinations were included. The parameters used and studied were age, sex, marital status, blood and results microbiological examinations for HIV, hepatitis B, C, and syphilis. The prevalence of blood donors who presented a serological abnormality is 3.95% with a predominance of donors with hepatitis B (72.93%) followed by syphilis (18.29%) of the hepatitis C (6.95%) and HIV (1.80%) and a predominance of young people. Conclusion: At the CNTS Antananarivo, the HBV is the main definitive reason for exclusion of these donors. This high prevalence is a real public health problem for the country's health authorities. The search for maximum safety in blood transfusion through firstly a better selection of blood donors by implementing a policy of strong loyalty and other early diagnosis of major diseases transmissible by blood and likely to infect the recipient. KEYWORDS: Antananarivo; Blood donor; Microbiology; Seroprevalence

Séroprévalence de la cysticercose et facteurs de risque associés chez un groupe de patients vus au Centre Hospitalier Régional de Référence d’Antsirabe, Madagascar

Introduction: A Madagascar, la cysticercose, maladie causée par la forme larvaire de Taenia solium, demeure un problème de santé publique. En 2003, la séroprévalence de la cysticercose variait entre 7% et 21% avec un taux plus élevé dans les régions centrales de l’île. Toutefois, depuis une dizaine d’année, les données épidémiologiques concernant la cysticercose humaine restent limitées. Notre étude a pour objectif de déterminer, chez les patients issus de la région de Vakinankaratra et qui sont suspects cliniquement, la séroprévalence de la cysticercose par Western blot ainsi que les facteurs de risque associés. Méthodes: Il s’agit d’une étude descriptive transversale menée sur une période de 6 mois au sein du Centre Hospitalier Régional de Référence d’Antsirabe. Tous les patients inclus dans l’étude ont répondu à un questionnaire clinique recueillant leurs caractéristiques sociodémographiques et culturelles ainsi que leurs habitudes alimentaires et leurs symptômes cliniques. Résultats: La séroprévalence de la cysticercose retrouvée dans la population d’étude était de 14,8% (35/237). Ce taux ne diffère pas significativement selon le sexe, l’âge, la consommation de viande de porc ou le mode de préparation de la viande (p > 0,05). Par contre, une différence significative (p < 0,05) a été observée chez les sujets présentant des nodules sous-cutanés ou un résultat de cysticercose antérieur positif. Conclusion: L’index élevé d’exposition à Taenia solium retrouvé dans notre étude justifie le renforcement des mesures de contrôle et de prévention déjà implantés dans le pays

Acid fast bacillus pulmonary and extra pulmonary in a laboratory of university hospital center in Antananarivo, Madagascar since 2003-2014

Background: Tuberculosis has even been a grave public health problem in Madagascar, one of the main causes responsible for death at the hospital for active and productive people.Methods: It was a descriptive and analytical retrospective study of patient records admitted for the research of acid-fast bacillus (AFB) pulmonary and extra pulmonary from January 2003 to December 2014 at the microbiology laboratory of the University Hospital Joseph Ravoahangy Andrianavalona (HU-JRA) Antananarivo, Madagascar. We did this study in order to describe the epidemiology of pulmonary and extra pulmonary tuberculosis at the laboratory. All of the requests about researching AFB for bacterial analysis have been received. Incomplete folders have been rejected. Age, sex, clinic information and the results of AFB research have been analyzed.Results: During 12 years, 1060 requests have been received to research AFB with 89 cases (8.39%) of positivity. Patients were between 9 months and 93 years old. The middle patient age was 41.7 years. Sex-ratio of infected patients was 1.36. There was a significant difference between gender and positive cases (p=0,001). 82 positive cases (93.77%) were pulmonary localization and 7 cases of extra pulmonary (6.23%).Conclusions: Despite the lack of screening, the high rate of bacillary pulmonary tuberculosis found was one of the great epidemiological importances because of their contagiousness. It is obvious that only health actions cannot solve the problem of tuberculosis.