Co-occurrence of blaNDM-1 and blaOXA-23 in carbapenemase-producing Acinetobacter baumannii belonging to high-risk lineages isolated from burn patients in Tunisia.

AIMS: Carbapenem-resistant Acinetobacter baumannii (CR-Ab) is an important cause of infections in burn patients. This study aimed to characterize the antimicrobial susceptibility pattern of CR-Ab isolated from burns in Burn Intensive Care Unit (BICU) of the Trauma and Burn Centre of Ben Arous, to determine the prevalence of ß-lactamase-encoding genes and to search eventual genetic relatedness of CR-Ab strains. METHODS AND RESULTS: From 15 December 2016 to 2 April 2017, all nonduplicated CR-Ab isolated in burn patients in the BICU were screened by simplex Polymerase Chain Reaction (PCR) for the class A, B, C, and D ß-lactamase genes. Sequencing was performed for NDM gene only. Genetic relatedness was determined by using pulsed field gel electrophoresis (PFGE) and by multilocus sequence typing. During the study period, 34 strains of CR-Ab were isolated in burns, mainly in blood culture (n = 14) and central vascular catheter (n = 10). CR-Ab strains were susceptible to colistin but resistant to amikacin (91%), ciprofloxacin (100%), rifampicin (97%), and trimethoprim-sulfamethoxazole (100%). All strains harbored blaOXA-51-like and blaOXA-23 genes, only or associated to blaGES (n = 26; 76%), blaADC (n = 20; 59%), blaPER-1 (n = 6; 18%) or/and blaNDM-1 (n = 3; 9%). PFGE identified 16 different clusters and revealed that most strains belonged to one major cluster A (n = 15; 44.1%). Among NDM-1 isolates, two were clonally related in PFGE and belonged to two single locus variant sequence type ST-6 and ST-85. CONCLUSIONS: This is the first description of clonally related NDM-1 and OXA-23-producing A. baumannii strains in the largest Tunisian BICU associated with two single locus variant sequence types ST6 and ST85.

Detection of carbapenem resistant Pseudomonas aeruginosa co-harboring blaVIM-2 and blaGES-5 in burn patients.

Pseudomonas aeruginosa is one of the major infectious agents in burn patients. Globally, high rates of antimicrobial resistance in P. aeruginosa have been reported, which is a cause of concern. The objective of this study was to determine the rate of resistance to carbapenems in P. aeruginosa isolates recovered from burn patients in Tunisia, to search genes encoding for carbapenemases and to determine their epidemiological markers (serotypes). A retrospective study was conducted in the Burn Intensive Care Unit (BICU) of the Trauma and Burn Centre of Ben Arous, Tunisia, and P. aeruginosa isolates collected from burn patients, from January to December 2018 were investigated. Carbapenemase screening was performed by Carbapenem Inactivation Method (CIM) and by EDTA-disk test for all carbapenem resistant isolates. Genes encoding carbapenemases (blaVIM, blaIMP, blaGES, blaNDM, and blaKPC) were investigated by PCR and selected carbapenemase genes were sequenced. During the study period, 104 non duplicated P. aeruginosa isolates were recovered. Most of them were isolated from skin samples (45.1%) and blood culture (22.1%) and belonged to O:11 (19.2%), O:12, and O:5 (12.5%, each) serotypes. High rates of resistance were observed for carbapenems (64.4%). Among the 67 carbapenem resistant isolates, 58 (86.5%) harbored blaVIM gene and 55 (82%) blaGES gene; in addition, 48 (71.6%) co-harbored blaVIM and blaGES genes. After sequencing, the blaVIM-2 and blaGES-5 gene variants were identified in seven randomly selected isolates. To the best of our knowledge, this is the first description of P. aeruginosa simultaneously harboring blaVIM-2 and blaGES-5 genes.

Methicillin-Resistant Staphylococcusaureus Strains Isolated from Burned Patients in a Tunisian Hospital: Molecular Typing, Virulence Genes, and Antimicrobial Resistance.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of a variety of infections in hospitals and the community. Their spread poses a serious public health problem worldwide. Nevertheless, in Tunisia and other African countries, very little molecular typing data on MRSA strains is currently available. In our study, a total of 64 MRSA isolates were isolated from clinical samples collected from burned patients hospitalized in the Traumatology and Burns Center of Ben Arous in Tunisia. The identification of the collection was based on conventional methods (phenotypic and molecular characterization). The characterization of the genetic support for methicillin resistance was performed by amplification of the mecA gene by polymerase chain reaction (PCR), which revealed that 78.12% of S. aureus harbors the gene. The resistance of all the collection to different antibiotic families was studied. Indeed, the analysis of strain antibiotic susceptibility confirmed their multi-resistant phenotype, with high resistance to ciprofloxacin, gentamicin, penicillin, erythromycin, and tetracycline. The resistance to the last three antibiotics was conferred by the blaZ gene (73.43%), the erm(C) gene (1.56%), the msr(A) gene (6.25%), and tet(M) gene (7.81%), respectively. The clonal diversity of these strains was studied by molecular typing of the accessory gene regulator (agr) system, characterization of the SCCmec type, and spa-typing. The results revealed the prevalence of agr types II and III groups, the SCCmec type III and II cassettes, and the dominance of spa type t233. The characterization of the eight enterotoxins genes, the Panton-Valentine leukocidin and the toxic shock syndrome toxin, was determined by PCR. The percentage of virulence genes detected was for enterotoxins (55%), tst (71.88%), leukocidin E/D (79.69%), and pvl (1.56%) factors. Furthermore, our results revealed that the majority of the strains harbor IEC complex genes (94%) with different types. Our findings highlighted the emergence of MRSA strains with a wide variety of toxins, leukocidin associated with resistance genes, and specific genetic determinants, which could constitute a risk of their spread in hospitals and the environment and complicate infection treatment.

Widespread of the Vienna/Hungarian/Brazilian CC8-ST239-SCCmec III MRSA clone in patients hospitalized in the Tunisian Burn and Traumatology Center.

The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is a major global public health concern. The current study sought to characterize 25 MRSA clinical isolates collected in a Tunisian hospital from December 2015 to September 2016, with the genetic lineages, virulence factors, and antibiotic resistance mechanisms determined for these isolates. Three spa-types were detected: t037 (23 isolates), t932, and t2235 (one isolate each). Isolates were ascribed to agr I (n = 20), agr II (n = 1), with four nontypeable isolates. Depending on sequence type (ST), the 25 MRSA isolates were assigned to two clonal complexes (CC8 and CC5), with a predominance of the lineage ST239-CC8 (n = 24; 96%). All isolates belonging to CC8 had the SCCmec type III, while the unique CC5 isolate had SCCmec type IV. Antimicrobial susceptibility testing revealed high levels of resistance to aminoglycosides, tetracycline, ciprofloxacin and rifampicin for the majority of isolates belonging to the ST239-CC8 lineage. The ST149-CC5 isolate was susceptible to non-ß-lactam antibiotics. One isolate harbored the tsst-1 gene (4%); however, lukS/LukF-PV, eta and etb genes were not detected. The MDR ST239-CC8 clone would seem to be widespread in this hospital. Therefore, a rigorous hygienic control system is urgently required.

Dissemination of epidemic ST239/ST241-t037-agrI-SCCmecIII methicillin-resistant Staphylococcus aureus in a Tunisian trauma burn intensive care unit.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen causing health care-infections in the world, especially in burns. The aim of this study was to assess the extent of dissemination of MRSA isolated from burn patients in Burn Intensive Care Unit in Tunisia and to evaluate the frequency of virulence and antibiotics resistance genes. Among the 72 S. aureus isolates analyzed in the study, 54% were MRSA. The majority of MRSA (94.8%) were multidrug resistant and they had a high resistance rates to kanamycin (94.8%), tobramycin (90%), tetracycline (94.8%) and ciprofloxacin and rifampicin (87%, each). The gene aac(6')-Ie-aph(2″)-Ia conferring resistance to kanamycine and tobtamycin were detected in all isolates and the aph(3')-Ia gene conferring resistance to gentamicin were detected in 2.8% of resistant isolates. Tetracycline resistance genes tet(M), tet(K) and tet(L) were detected in 100%, 10.8% and 2.8% of the isolates, respectively. The SCCmec type III and the agr type I were the most predominant (69.2% and 90%, respectively). The 27 SCCmecIII-agrI isolates were clustered into two PFGE types A and B. The two representative isolates of PFGE clusters A and B belonged to ST239-t037 and ST241-t037 respectively. As conclusion, our results showed a high prevalence of MRSA in trauma burn intensive care unit belonging to two multidrug resistant clones ST239/ST241-agrI-t037-SCCmecIII MRSA. We also demonstrated that MRSA was disseminated between burn patients.

Clonal spread of PER-1 and OXA-23 producing extensively drug resistant Acinetobacter baumannii during an outbreak in a burn intensive care unit in Tunisia.

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 ß-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 ß-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.

SARS-CoV-2 infection virological diagnosis.

SARS-CoV-2 infection has to be confirmed by virological diagnosis. Multiple diagnostic tests are available without enough perspective on their reliability. Therefore, it is important to choose the most suitable test according to its sensitivity and specificity but also to the stage of the disease. Currently, the RT-PCR detection of the viral genome in respiratory samples is the most reliable test to confirm the diagnosis of an acute SARS-CoV-2 infection. It has to be done in Class II biological safety laboratory. However, it may lack sensitivity, particularly in the advanced phase of infection, and depends closely on the samples' quality. Rapid PCR by cartridge system reduces response times but is not suitable for laboratories with high throughput of requests. Detection of virus antigens on respiratory samples is a quick and easy to use technique; however it has not good specificity and sensitivity and cannot be used for diagnosis and patient management. The detection of specific antibodies against SARS-CoV-2 is better used for epidemiological analyses. Research should be encouraged to overcome the limits of the currently available diagnostic tests.

Molecular profile of carbapenemase-producing Enterobacterales in burn patients.

BACKGROUND: Carbapenemase-producing Enterobacterales (CPE) present a threat to public health worldwide. AIM: To study their prevalence at the Trauma and Burn Center's Burn Unit and investigate their molecular characteristics and their associated antibiotics resistance patterns. METHODS: This is a retrospective study conducted at the Trauma and Burn Center's laboratory between july 2017 and december 2018. It included all patients hospitalized in the Trauma and Burn Center's Burn Unit infected with Enterobacterales resistant to carbapenems. The search of the carbapenemases genes was performed by PCR amplification GeneXpert® IV (Cepheid, Sunnyvale, CA, USA) by Xpert® Carba-R kit. RESULTS: During the study period, among 574 Enterobacterales, 64 strains (11.1%) were resistant to carbapenems, 58 strains (90.6%) of which were CPE. K. pneumoniae was the most predominant bacteria (n=50) fllowed by E. cloacae (n=7), P. mirabilis (n=3), E. aerogenes (n=2), E. coli (n=1) and P. rettgeri (n=1). The most common carbapenemase gene was blaNDM gene (58.6%) followed by blaOXA48 (24.1%). The co-existence of these two genes was identified in ten strains (17.3%). For the 58 CPE, resistance to ertapenem, imipenem and meropenem was 100%, 18.4% and 36.2%, respectively. The highest resistance rates were found to third-generation-cephalosporins (100%), ciprofloxacin (95%) and gentamicin (89.7%). Fosfomycin and colistin had the best susceptibility in vitro with only 5.2% and 4.8% of resistance, respectively. CONCLUSION: The high prevalence of CPE in our center requires continued screening and reinforcement of hygiene measures.

Rapid diagnostic tests : Pros, cons and potential use in the COVID-19 management in Tunisia.

OBJECTIVES: Diagnosis of SARS-CoV-2 infection is a major public health issue. In a context of limited diagnostic capacity with the reference technique (real-time RT-PCR), many manufacturers have developed rapid diagnostic tests (RDTs). Although very promising in theory, these tests have raised many questions. This article is a rapid review that synthesizes data regarding different types of available RDTs, their performance, their limits and their potential indications in Tunisia as proposed by a multidisciplinary group of experts. METHODS: A literature review was carried out on the websites of international organizations, governmental bodies and on INAHTA database, completed by a search of relevant scientific articles up to 1 June 2020. The synthesis of the data was submitted to a panel of experts to propose recommendations for the Tunisian context. RESULTS: RDTs based on the detection of antigens and antibodies have sensitivity and specificity related issues. Few validation reports are published in the scientific literature. Pending more evidence on their performance and validity, several international organizations recommend their use only for research purposes. TDRs based on antibody detection are not appropriate for the early diagnosis of COVID-19. However, validated and specific tests could provide complementary diagnostic information to reference tests. CONCLUSION: Pending further evidence, the panel recommends the use of RDTs mainly for research purposes at the community level.

[Comparative study of antibiotic resistance in bacteria isolated from burned patients during two periods (2005-2008, 2008-2011) and in two hospitals (Hospital Aziza Othmana, Trauma and Burn Center)]. / Etude comparative de la résistance aux antibiotiques des principales bactéries isolées au service de Réanimation de brûlés durant deux périodes (2005-2008, 2008-2011) et dans deux structures hospitalières (Hôpital Aziza Othmana, Centre de traumatologie et grands brules ben Arous.

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.

Epidemiological profile and antibiotic resistance of Pseudomonas aeruginosa isolates in burn and Traumatology center in Tunisia over a three-year period.

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 EDTAtest. 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.

[Bacteriological profile of urinary tract infections in women in Aziza Othmana Hospital: 495 cases]. / Profil bactériologique des infections urinaires chez la femme à l'Hôpital Aziza Othmana: étude à propos de 495 cas.

BACKGROUND: Urinary infection is a frequent pathology in the community as well as at the hospital. AIM: To analyze the profile of bacteria isolated from urinary tract infectious in women and their antimicrobial resistance. METHODS: During two year period (1 January 2005 to 31 December 2006), 4536 urinary specimens were analyzed at the Laboratory of Aziza Othmana Hospital. All bacteria isolated from urinary tract infection (UTI) at women were retrospectively reviewed. RESULTS: 495 cases of UTI were collected during this period. They were recovered from out patients (67%) or from hospitalized patients in Gynecology and obstetrics (23%). Enterobacteriacae were the most frequently identified strains (90.4%) including Escherichia coli (71%). The identified strains presented natural resistance and a high frequency of acquired resistance to betalactams(60.3% of E.coli, 72% of P.mirabilis were resistant to amoxicillin)and cotrimoxazole(30.4% of E.coli, 19,1 of K.pneumoniae, 21.4% of P.mirabilis). 5.7% of K.pneumoniae and 1.8% of E.coli were producing extended spectrum betalactamase(ESBL). Aminoglycosides remained active on enterobacteriacae(resistance to amikacin<14%,gentamicin<5%).Ofloxacin was highly active against enterobacteriacae (resistance<14%) CONCLUSION: Enterobacteriacae were the most frequent species in women urinary tract infection. Among these isolates, a high frequency of acquired resistance to betalactams and cotrimoxazole was shown. Aminoglysosides and fluoroquinolones remained the most active drugs. In every case antibiotherapy should have been prescribed after performing an antibiogram for each strain. These data were useful for the first line antibiotherapy, however the antimicrobial susceptibility testing is necessary for the rational use to limit the highly active drugs to multiresistant strains.

The impact of fluoroquinolones use on antibiotic resistance in an intensive care burn department.

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. 0 5 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. CONCLUSION: 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.

The impact of fluoroquinolones use on antibiotic resistance in an intensive care burn department.

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.

[Surveillance of multidrug resistant bacteria in a Tunisian hospital]. / Surveillance des bactéries multirésistantes dans un hôpital Tunisien.

BACKGROUND: Controlling antibiotic resistance of bacteria is a priority for public healthcare. AIM: This study concerned the frequency of multidrug resistant bacteria (MDRB) in a Tunisian Hospital with the aim of establishing guidelines for MDRB prevention. METHODS: The study was conducted during two years (1 January 2005-31 December 2006). Samples collected for the clinical diagnostic were included. The MDRB concerned were: methicillin resistant Staphylococcus aureus(MRSA), Enterobacteriacae resistant to of third generation cephalosporin (ER3GC), Acinetobacter baumannii resistant to both imipenem and ceftazidime, Pseudomonas aeruginosa resistant to both imipenem and ceftazidime. RESULTS: During the study period, 2475 bacteria were tested by disk diffusion. 597 MDRB were collected, the rate of MBR was 24.1%. These MDRB were mainly recovered in burn unit (82.6%). ER3GC (47%) and MRSA (29,2%) were the most frequent MDRB. A. baumannii and P. aeruginosa multiresistant concerned 14,8% and 9% of MDRB. MDRB were isolated mainly from blood cultures (45%). The rate of MRSA was 46.4% among 375 strains of S. aureus. ER3GC represented 25,6% among 1096 isolates. Concerning A. baumannii and P. aeruginosa, 51.7% and 20.5% were resistant to both imipenem and ceftazidime among 170 and 264 isolates. Antibiotic resistance evolution showed a decrease of resistance in 2006 versus 2005. This decrease should be explained by the improvement of hygiene measure especially hand washing with the introduction of hydro- alcoholic solutions, a better targeted antibiotherapy promoted by a close cooperation between microbiologists and clinicians. CONCLUSION: The MDRB were frequent in our hospital. They were mainly isolated from the burn department. The measures of prevention already implemented are effective and must be strengthened with the continuous surveillance of MDRB.

[Bacteriological profile and antibiotic resistance of bacteria isolates in a burn department]. / Profil bactériologique et résistance aux antibiotiques des bactéries isolées dans un service de réanimation des brûlés durant deux ans.

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.

[Evolution of antibiotic consumption in an intensive care burn department]. / Evolution de la consommation des antibiotiques dans un service de réanimation de brûlés.

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.

[A study of sensitivity to antibiotics for Staphylococcus aureus strains isolated in a department of resuscitation of badly burnt patients]. / Etude de la sensibilite aux antibiotiques des souches de Staphylococcus aureus isolees au service de reanimation des brûles.

Methicillin resistant Staphylococcus aureus (MRSA) constitutes one of the main causes of nosocomial infections in badly burnt patients. The purpose of our study was to determine the frequency and evolution of Methicillin resistant Staphylococcus strains in the department of resuscitation of badly burnt patients of Hopital AZIZA OTHMANA. From January 1, 2000 to December 31, 2003, tests for Staphylococcus aureus proved positive in 139 patients on at least, one occasion. Mean age of patients was 34 years and their sex ratio 1.7. 59.7% of the accidents were house hold accidents, and 70% of them were of thermal native. The average burnt cutaneous surface area was 44%. Sepsis occurred 7 days on average after admission to hospital. Hospital stay for this group varied between 3 and 140 days, outcome was fatal in 13 cases. MRSA occurred in 69% of cases. As for the other families of antibiotics, the frequencies of resistance remained elevated for tetracyclines, cotrimoxazole, gentamicine, erythromycine.

[Pseudomonas aeruginosa: a multicentric study of antibiotic resistance (1999-2000)]. / Pseudomonas aeruginosa: étude multicentrique de la résistance aux antibiotiques (1999-2000).

A retrospective multicentric study was carried out over a period of 2 years (1999-2000). 2659 strains of Pseudomonas aeruginosa were collected from 4 university hospitals (Charles Nicolle Hospital, Pediatric Hospital and National Centre of Bone Marrow Transplantation in Tunis, Habib Bourguiba Hospital in Sfax). Epidemiological profile and antibiotic susceptibility were analysed. All bacteria were identified by conventional methods and antibiotic susceptibility tests were performed according to CA-SFM guidelines. The strains were recovered essentially from surgical wards (33%) and intensive care units (22%). Pseudomonas aeruginosa was isolated mainly from pus (36%), urine (32%) and respiratory samples (18%). 25% of strains were resistant to ticarcilline, 18% to cefsulodine, 9% to ceftazidime, 14% to imipenem and amikacin and 25% to ciprofloxacin. Moreover, the resistance rates varied from hospital to hospital and from unit to another. The resistant strains were isolated particularly from urology and intensive care units: respectively 62% and 39% for ticarcilline; 26% and 13% for ceftazidime. The acquired resistance to b-lactams seems largely due to penicillinase production. The frequency of resistance to ceftazidime was the lowest and seems associated to chromosomal cephalosporinase over production.