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Extensively drug resistant Acinetobacter baumannii (XDR-Ab), has emerged as an important pathogen in several outbreaks. The aim of our study was to investigate the eventual genetic relatedness of XDR-Ab strains recovered from burn patients and environment sites in the largest Tunisian Burn Intensive Care Unit (BICU) and to characterize β-lactamase encoding genes in these strains. Between March 04th, 2019 and April 22nd, 2019 an outbreak of XDR-Ab was suspected. Environmental screening was done. All isolates were screened by simplex PCR for β-lactamase genes. Genetic relatedness was determined by pulsed field gel electrophoresis (PFGE) of ApaI-digested total DNA. During the study period, 21 strains of A. baumannii were isolated in burn patients, mainly in blood culture (n = 7) and central vascular catheter (n = 6). All strains were susceptible to colistin but resistant to imipenem (n = 23), ciprofloxacin (n = 23), amikacin (n = 22), tigecyclin (n = 5) and rifampicin (n = 4). The blaOXA-51-like, blaOXA23, and blaADC genes were present in all strains. These resistance determinants were associated with blaPER-1 in 10 strains. The ISAba1 was inserted upstream of blaOXA-23 in all isolates. PFGE revealed two major clusters A (n = 11) and B (n = 5). This is the first description in Tunisia of clonally related PER-1 producing XDR-Ab in burn patients with probable environmental origin.

Background: Continuous monitoring of the bacterial flora and antibiotic resistance of the main bacteria involved in nosocomial infections helps improve treatment and prevention strategies., Aim: To compare the bacteriological profile and antibiotic susceptibility of the main bacterial isolates within the burned patients over two periods of 3 years and in two hospitals., Methods: During two three-year periods: period 1 (P1): 1/7/2005-30/6/2008 and period 2 (P2): 1/7/2008-30/6/2011) and in two hospitals: Hospital Aziza Othmana (HAO) and the traumatology and burn center (CTGB), 2153 and 3719 non-repetitive strains were isolated from burn patients from different samples. The transfer of the intensive care unit was made on 01/07/2008 from the Hospital Aziza Othmana to CTGB. The study of antibiotic sensitivity was performed according to CA-SFM., Results: During the period P1, Pseudomonas aeruginosa was the main bacteria isolated (18%) followed by Staphylococcus aureus (14%) and Acinetobacter baumannii (12%). After the transfer of intensive care burn unit to the traumatology center, ecology bacterial varied with S. aureus (20%) in the first place followed by P. aeruginosa (15%) and Proteus mirabilis (11%). The study of the evolution of antibiotic susceptibility showed an overall downward trend of resistance in the second half of 2008, immediately after the transfer of service in the new hospital structure. The rate of ceftazidim resistant Klebsilella pneumoniae decreased from 80.4% to 50%, Similarly the resistance of P. aeruginosa to ceftazidime and imipenem decreased respectively from 61% to 39.4% and from 63.3% to 37.1%. Nevertheless, the reduction of resistance was followed by a rapid increasing during the year 2009 to reach overall rates of resistance previously observed in the hospital Aziza Othmana. Concerning S. aureus, the rate of MRSA (methicillin-resistant S. aureus) showed no significant variation throughout the study period: 60% versus 56.3% at HAO and CTGB. A. baumannii brings up the problem of mutirésistance: 92.7% of strains were resistant to ceftazidime and 63.9% to imipenem during P1 with an emphasis on resistance to imipenem during P2 increased to 89.3%., Conclusion: Resistance is a problem in the intensive care burn unit. Preventive measures have to be taken.

Background: Pseudomonas aeruginosa is a known opportunistic pathogen frequently causing serious infections in burned patients., Aim: To analyze the epidemiological profile of Pseudomonas aeruginosa isolated in a Tunisian burn unit., Methods: During a 3-year period (from 01 July 2008 to 30 June 2011), 544 non repetitive strains of P. aeruginosa were isolated from burn patients. Susceptibility to antibiotics was assessed according to CA-SFM guidelines. Serotypes were identified by slide agglutination test using P.aeruginosa O antisera (Biorad). Producing carbapenemase was analyzed for 202 imipenem resistant isolates by EDTA test. Susceptibility testing data were stored in a laboratory data base using whonet 5.3 software., Results: The most frequent sites of isolation were cutaneous infections and blood cultures (83.4%). The percentages of resistant isolates were as follows: ceftazidime: 34%; imipenem: 37.1%, ciprofloxacin: 27.1% and amikacin: 29.6%. The most prevalent serotypes were: 011(51%), 06(17%), 03 (8%), 04(12%), 012(5%). Among the 202 imipenem resistant strains, 58% expressed a metallocarbapenemase. All theses strains were resistant to all tested antibiotics except colistin and belonged to the serotype O11., Conclusion: The dissemination of carbapenemases strains must be contained by implementation of timely identification, strict isolation methods and better hygienic procedures.

Background: Fluoroquinolones (FQ) use has been identified as a risk factor for colonization and infection to methicillin resistant Staphylococcus aureus(MRSA), Pseudomonas aeruginosae multiresistant(PMR) , Acinetobacter multiresistant (AMR) and multidrug resistant bacteria(MDRB)., Aim: Our study proposes to measure the annual antibiotic use of FQ and antimicrobial resistance in P. aeruginosa, S. aureus, Klebsiella pneumoniae and A. baumannii in an intensive care burn unit., Methods: The study was conducted during a 4 year period (1 January 2000 to 31 December 2003). Antimicrobial susceptibility testing was performed using the disk diffusion method as recommended by the French Society of Microbiology. The consumption of the following antibiotics: ofloxacin, ciprofloxacin was expressed as the antimicrobial use density (AD) taking into account the quantity of antibiotics in Grams converted to defined daily doses (DDD) and the number of day hospitalization. Statistical significance was defined as p value < 0.05 for the corresponding correlation coefficient., Results: There were statistically significant relationship between use of ciprofloxacin and resistance in P. aeruginosa to this drug (rs=0.95, p<0.05). Moreover, the ciprofloxacin consumption was correlated with resistance to imipenem (rs=0.95, p<0.05) and ceftazidime (rs=0.95, p<0.05) in P. aeruginosa . A restriction use of ciprofloxacin has been taken during 2003, it is followed by a significant decrease of resistance to imipenem, ceftazidime and ciprofloxacin in P. aeruginosa (p<0, 05). The use of fluoroquinolones was correlated significantly with MRSA (rs=0.96, P<0.05) . The restriction use of FQ was significantly associated with a decrease of MRSA. The consumption of ciprofloxacin was also correlated (P<0.05) with resistance of ceftazidime in K. pneumoniae. However, there is not a correlation (P> 0.05) between fluoroquinolones use and resistance in A. baumannii as well in ciprofloxacin, imipenem and ceftazidime. Our study illustrates the pressure of selection of fluoroquinolones use in the development of MDRB. The use and or the duration of treatment with theses antibiotics should be rationalised as part of efforts to control the emergence of multidrug resistant bacteria.

Background: Nosocomial infections remain the main cause of morbidity and mortality in burn patients. Ongoing surveillance of infections in burned patients is essential to detect changes in epidemiology and to guide better empirical antibiotherapy and infection control policies. The aim of this study is to analyze the bacterial flora and the antibiotic resistance of isolates in a burn department during a two year period, Methods: From 1 January 2005 to 31 December 2006, 1268 strains were isolated from different specimens. Antimicrobial susceptibility testing has been carried out by disk diffusion method as referred to the French Society of Microbiology. All data were stored in a laboratory data base using whonet 5.3 software. Duplicate isolates defined as the same bacterial species for the same patient with the same antimicrobial susceptibility profile were excluded., Results: The most frequently identified species were Staphylococcus aureus (19.8%), Pseudomonas aeruginosa (15.8%), Acinetobacter baumannii (11.8%), Providencia stuarttii. The rate of meticillin resistant S. aureus was 68.1%, all isolates were fully susceptibles to glycopeptide. P. aeruginosa resistance was 35.6% and 35.4% respectively for ceftazidime and imipenem. Concerning A. baumannii, 98.7% of strains were resistant to ceftazidime, 59.5% to imipenem and 87.5% to ciprofloxacin. 77.3% of P. stuarttii isolates were resistant to ceftazidime and were producing extended spectrum, lactamase (ESBL). The frequencies of resistance to ceftazidime, of loxacin and amikacin of K. pneumoniae were respectively 60.9%, 25.4% and 47.1%., Conclusion: Comparatively to the previous years, S. aureus still be the commonest pathogen in the burn department. The incidence of antimicrobial resistance has decreased during 2006 after a peak of multiresistance during 2005. Our results should be helpful in providing useful information regarding antimicrobial resistance among the burn isolates and this will help in formulation of effective guideline for therapy.

Background: The increasing consumption of antibiotics in hospitals and the economic implications of this increase lead to survey this consumption in the various hospital units., Aim: Our study proposes to measure the annual antibiotic use and antimicrobial resistance in an intensive care Burn department in order to manage the control measures., Methods: The study was conducted during a 5 year period (1 January 2000 to 31 December 2004). The average number of admissions was 204/year and the mean number of hospitalisation was 4036/year. Antimicrobial susceptibility testing was performed by disk diffusion method. Susceptibility testing data were stored in a laboratory data base using whonet 5.3 software. The consumption of following antibiotics: imipenem, ceftazidime, ofloxacin, ciprofloxacin, piperacillin-tazobactam was measured by antimicrobial density (AD) witch takes into account the quantity of antibiotics in Grams converted to daily defined dose (DDD) and number of hospitalization days. The daily defined dose (DDD) was proposed by WHO. The calculation of the AD for each molecule was earned Out according to the following formula: AD = (Quality consumed in for the particular antimicrobial x 1000) / (DDD for that antimicrobial x number of days of hospitalizations)., Results: There was statistically significant relationship between increasing use of ceftazidime and ceftazidime resistant Klebsiella pneumoniae (rs = 0.93; p = 0.O2) The use of ceftazidime was not significantly associated with resistance to this molecule in P. aeruginosa (rs = 0.76 p = 0.13). Conceerning the fluoroquinolones, there was statistically significant relation ship between increasing use of ciprofloxacin and rate ciprofloxacin resistant P. aeruginosa (rs = 0.89, P = 0.043). Furthermore, the consumption of ciprofloxacin was significantly correlated to imipenem resistance in P. aeruginosa (rs = 0.87, p = 0.05). However, the consumption of imipenem was not significantly correlated to resistance of this drug in P. aeruginosa (rs = 0.45; P = 0.4)., Conclusion: The monitoring of both antibiotic consumption and antibiotic resistance is necessary to set up targeted policies and to control their effectiveness. Nevertheless this monitoring must be integrated into global policy of good use and control of antibiotics.

Background: The increasing consumption of antibiotics in hospitals and the economic implications of this increase lead to survey this consumption in the various hospital units., Aim: Our study proposes to measure the annual antibiotic use and antimicrobial resistance in an intensive care Burn department in order to manage the control measures., Methods: The study was conducted during a 5 year period (1 January 2000 to 31 December 2004). The average number of admissions was 204/year and the mean number of hospitalisation was 4036/year. Antimicrobial susceptibility testing was performed by disk diffusion method. Susceptibility testing data were stored in a laboratory data base using whonet 5.3 software. The consumption of following antibiotics: imipenem, ceftazidime, ofloxacin, ciprofloxacin, piperacillin-tazobactam was measured by antimicrobial density (AD) witch takes into account the quantity of antibiotics in Grams converted to daily defined dose (DDD) and number of hospitalization days. The daily defined dose (DDD) was proposed by WHO. The calculation of the AD for each molecule was carried out according to the following formula: [AD = Quantity consumed in grams for the particular antimicrobial X 1000]/[DDD for that antimicrobial X number of days hospitalizations]., Results: There was statistically significant relationship between increasing use of ceftazidime and ceftazidime resistant Klebsiella pneumoniae (rs=0.93; p=0.02). The use of ceftazidime was not significantly associated with resistance to this molecule in P. aeruginosa (rs=0.76 ; p=0.13). Concerning the fluoroquinolones, there was statistically significant relation ship between increasing use of ciprofloxacin and rate ciprofloxacin resistant P. aeruginosa (rs=0.89,P=0.043). Furthermore, the consumption of ciprofloxacin was significantly correlated to imipenem resistance in P. aeruginosa (rs=0.87, p=0.05 ). However, the consumption of imipenem was not significantly correlated to resistance of this drug in P. aeruginosa (rs=0.45; P=0,4)., Conclusion: The monitoring of both antibiotic consumption andantibiotic resistance is necessary to set up targeted policies and to control their effectiveness. Nevertheless this monitoring must be integrated into global policy of good use and control of antibiotics.