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1.
Acta Microbiol Immunol Hung ; 71(1): 61-68, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38381147

RESUMO

Carbapenem resistant Enterobacteriaceae (CRE) are major human pathogens because, these cause high number of difficult-to-treat infections. Allogeneic hematopoietic stem cell transplant (AHSCT) recipients are highly exposed to these type of bacteria. The aim of our study was to investigate prevalence of CRE colonization in AHSCT patients and to determine genes encoding carbapenem resistance. A retrospective study conducted between January 2015 and December 2019, involved 55 patients colonized with CRE strains. We determined the rate of antibiotic resistance according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the carbapenem resistance genes by PCR assays for genes encoding most frequent ß-lactamases namely, blaGES, blaKPC, blaIMI, blaNDM, blaVIM, blaIMP and blaOXA-48. Eighty-one episodes of CRE colonization were recorded in 55 patients, mainly suffering from acute leukaemia (30%) and aplastic anemia (26%). History of hospitalization was noted in 80 episodes. Prior antibiotic treatment, severe neutropenia and corticosteroid therapy were respectively found in 94%, 76% and 58% of cases. Among the 55 patients, six patients (11%) developed a CRE infection. The CRE responsible for colonization were carbapenemase producers in 90% of cases. They belonged mostly to Klebsiella pneumoniae (61/81) and Escherichia coli species (10/81). Antibiotic resistance rates were 100% for ertapenem, 53% for imipenem, 42% for amikacin, 88% for ciprofloxacin and 27% for fosfomycin. Molecular study showed that blaOXA-48 gene was the most frequent (60.5%), followed by blaNDM (58%). Thirty-five (43%) strains were co-producers of carbapenemases. In our study, we report a high rate of CRE intestinal colonization in AHSCT recipients of our center.


Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos , Infecções por Enterobacteriaceae , Transplante de Células-Tronco Hematopoéticas , Humanos , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Estudos Retrospectivos , Testes de Sensibilidade Microbiana , Proteínas de Bactérias/genética , beta-Lactamases/genética , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Klebsiella pneumoniae/genética , Carbapenêmicos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Infecções por Enterobacteriaceae/epidemiologia , Infecções por Enterobacteriaceae/microbiologia
2.
J Appl Microbiol ; 135(3)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38346864

RESUMO

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.


Assuntos
Acinetobacter baumannii , Antibacterianos , Humanos , Antibacterianos/farmacologia , Acinetobacter baumannii/genética , Tunísia/epidemiologia , Testes de Sensibilidade Microbiana , beta-Lactamases/genética , Proteínas de Bactérias/genética , Tipagem de Sequências Multilocus
3.
Acta Microbiol Immunol Hung ; 71(1): 37-42, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38285075

RESUMO

Acinetobacter baumannii has emerged as a main nosocomial pathogen exhibiting high rates of resistance to clinically relevant antibiotics. Six pandrug-resistant A. baumannii (PDR-A. baumannii) were recovered from three patients in a Tunisian Intensive Care Unit (ICU) between 10th and 16th of May 2018 resulting in one fatal case and raising the possibility of an outbreak. On 18th of May environmental screening of ICU surfaces was carried out. On 22nd of May a fourth patient was infected with PDR-A. baumannii and died. A second investigation was carried out for environmental screening and PDR-A. baumannii was isolated from the respirator. Antimicrobial susceptibility testing was performed according to EUCAST (2019) guidelines. MIC of colistin was determined by broth microdilution method. PCR was used to detect 14 beta-lactamases/carbapenemases and mcr (mcr-1 to mcr-5) genes. The genetic relatedness of PDR-A. baumannii isolates was determined by PFGE and MLST. Seven PDR-A. baumannii isolates were recovered from four patients, one MDR strain from wash basin, a PDR strain from hand sanitizer bottle and another PDR strain from respirator. All PDR-A. baumannii (n = 9) harbored blaOXA-69 gene and none carried mcr. Moreover, seven carried blaGES and blaOXA-23 genes. PFGE identified four pulsotypes (A, B, C, and D) with the pulsotype A gathering seven PDR-A. baumannii isolates: six from three patients and one from hygiene sample. MLST revealed that all PDR-A. baumannii isolates of pulsotype A belonged to the pandemic clone ST2. Systematic screening of MDR and PDR-A. baumannii is highly recommended to limit dissemination of such strains in ICUs.


Assuntos
Acinetobacter baumannii , Infecção Hospitalar , Humanos , Proteína 1 Semelhante a Receptor de Interleucina-1/genética , Tipagem de Sequências Multilocus , Farmacorresistência Bacteriana Múltipla/genética , Infecção Hospitalar/epidemiologia , Antibacterianos/farmacologia , beta-Lactamases/genética , Proteínas de Bactérias/genética , Unidades de Terapia Intensiva , Surtos de Doenças , Testes de Sensibilidade Microbiana
4.
Acta Microbiol Immunol Hung ; 70(3): 199-205, 2023 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-37490366

RESUMO

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.


Assuntos
Antibacterianos , Infecções por Pseudomonas , Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , beta-Lactamases/genética , Carbapenêmicos/farmacologia , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/genética , Infecções por Pseudomonas/epidemiologia , Estudos Retrospectivos , Queimaduras/complicações , Queimaduras/microbiologia
5.
Acta Microbiol Immunol Hung ; 70(1): 52-60, 2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36525058

RESUMO

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.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus/genética , Infecções Estafilocócicas/epidemiologia , Genótipo , Testes de Sensibilidade Microbiana , Antibacterianos , Tetraciclina , Unidades de Terapia Intensiva
6.
Antibiotics (Basel) ; 11(10)2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36290048

RESUMO

BACKGROUND: Actually, no data on the prevalence of plasmid colistin resistance in Tunisia are available among clinical bacteria. OBJECTIVES: This study aimed to investigate the current epidemiology of colistin resistance and the spread of the mcr gene in clinical Gram-negative bacteria (GNB) isolated from six Tunisian university hospitals. METHODS: A total of 836 GNB strains were inoculated on COL-R agar plates with selective screening agar for the isolation of GNB resistant to colistin. For the selected isolates, mcr genes, beta-lactamases associated-resistance genes and molecular characterisation were screened by PCRs and sequencing. RESULTS: Colistin-resistance was detected in 5.02% (42/836) of the isolates and colistin-resistant isolates harboured an ESBL (blaCTX-M-15) and/or a carbapenemase (blaOXA-48, blaVIM) encoding gene in 45.2% of the cases. The mcr-1 gene was detected in four E. coli isolates (0.59%) causing urinary tract infections and all these isolates also contained the blaTEM-1 gene. The blaCTX-M-15 gene was detected in three isolates that also carried the IncY and IncFIB replicons. The genetic environment surrounding the mcr-carrying plasmid indicated the presence of pap-2 gene upstream mcr-1 resistance marker with unusual missing of ISApl1 insertion sequence. THE CONCLUSIONS: This study reports the first description of the mcr-1 gene among clinical E. coli isolates in Tunisia and provides an incentive to conduct routine colistin susceptibility testing in GNB clinical isolates.

7.
J Infect Prev ; 23(2): 75-78, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35340921

RESUMO

Microbial contamination of hematopoietic stem cells (HSC), used for autologous and allogenic transplantations, is rare but could cause serious blood stream infection in transplanted patients. These infections occur immediately, or later following the formation of biofilm on the catheter lumen. The present study describes an intermittent B. cepacia HSC contamination associated with nosocomial bacteremia: from October 2011 to April 2015, 17 B. cepacia strains were isolated in HSC bags (n = 14) and blood cultures (n = 3) in patients hospitalized in the National Bone Marrow Transplant Center. Two epidemiologic investigations in the National Blood Transfusion Center, allowing the isolation of three strains in hygiene samples, and four interventions in this institution were done. To identify the source of this contamination, a molecular investigation was done on 23 B. cepacia strains isolated in our center from 2007 to 2015. PFGE analysis revealed five clusters. The major cluster included 18 strains isolated from HSC bags (n = 14), blood culture (n = 1), and water cans and bath (n = 3). The second cluster (B) including only two and the remaining clusters (C, D, and E) contained single strains isolated before the epidemic period. These findings confirmed that the origin of the outbreak was the contaminated water used in the water bath during the thawing step of HSC bags. Based on this result, new sterile water was used for every defrosting, but HSC bags contamination persisted. In May 2015, the water bath was replaced with a dry bath and no B. cepacia strain was isolated from that date to April 2020.

8.
Clin Rheumatol ; 40(10): 4317-4323, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34097177

RESUMO

INTRODUCTION: Tuberculous Spondylodiscitis is the most common form of musculoskeletal tuberculosis. Molecular techniques on fresh tissues are proved to improve the diagnosis of tuberculous spondylodiscitis and to allow a rapid diagnosis to initiate the treatment and prevent neurological complications. OBJECTIVES: The objective of the present study was to assess the diagnostic performances of single tube nested PCR and GeneXpert ultra in the diagnosis of tuberculous spondylodiscitis on formalin fixed paraffin embedded tissues. METHODS: This study included 63 tuberculous spondylodiscitis cases collected from June 2014 to January 2020 and corresponding to 27 definite tuberculous spondylodiscitis with positive microbiology, and 36 probable tuberculous spondylodiscitis, with histopathological, clinical and radiological findings consistent with tuberculous spondylodiscitis but with negative microbiology. The sensitivity, specificity, positive predictive value and negative predictive value of nested PCR and GeneXpert ultra were determined with reference to microbiology. RESULTS: Nested PCR was positive in 47 (75%) cases: 26/27 definite tuberculous spondylodiscitis and 21/36 probable tuberculous spondylodiscitis. GeneXpert ultra was positive in only 6 (10%) cases corresponding to definite tuberculous spondylodiscitis. The sensitivity, specificity, positive predictive value and negative predictive value of nested PCR on formalin fixed paraffin embedded tissues were 96%, 100%, 100%, 83% respectively. For GeneXpert ultra, these rates were 22%, 100%, 100% and 25% respectively. CONCLUSION: Nested PCR and GeneXpert ultra on formalin fixed paraffin embedded tissues are useful tools for the diagnosis of tuberculous spondylodiscitis, especially for cases where microbiological investigations were not carried out. Both techniques have excellent specificity but single tube nested PCR is more sensitive. Key Points • Molecular techniques are routinely performed on fresh tissues • GeneXpert and nested PCR on formalin fixed paraffin embedded tissues are reliable for the diagnosis of tuberculous spondylodiscitis • Nested PCR is more sensitive than Genexpert for diagnosing tuberculous spondylodiscitis.


Assuntos
Discite , Tuberculose , Discite/diagnóstico , Formaldeído , Humanos , Inclusão em Parafina , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade
9.
Acta Microbiol Immunol Hung ; 68(2): 73-79, 2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-33999858

RESUMO

The purpose of our study was to investigate the epidemiology of coagulase negative staphylococci (CoNS) responsible for bacteremia in hematopoietic stem cell transplant (HSCT) recipients and to determine the prevalence and the genetic background of methicillin resistance. The prevalence of CoNS bacteremia was 7.4% (54/728), higher in allograft (10.7%) than in autograft (4.7%) recipients. A sepsis or a septic shock were observed in 9% of cases. No deaths were attributable to CoNS bacteremia. The methicillin resistance rate was 81%. All MR-CoNS, harbored mecA gene and 90% were typeable with SCCmec typing using PCR amplification. The SCCmec type IV was the most frequent (44%). Clonal dissemination of MR- Staphylococcus epidermidis strains was limited. Our study showed a low prevalence and favorable outcome of CoNS bacteremia in HSCT recipients with limited clonal diffusion. However, they were associated with a significant rate of severe infections and a high rate of methicillin resistance, mediated by SCCmec IV element in most cases.


Assuntos
Bacteriemia/epidemiologia , Coagulase/genética , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Infecções Estafilocócicas/epidemiologia , Staphylococcus/genética , Staphylococcus/patogenicidade , Adolescente , Adulto , Antibacterianos/farmacologia , Bacteriemia/microbiologia , Proteínas de Bactérias/genética , Criança , Coagulase/análise , DNA Bacteriano/genética , Feminino , Humanos , Masculino , Resistência a Meticilina/genética , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/etiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/genética , Tunísia/epidemiologia , Adulto Jovem
10.
Tunis Med ; 99(2): 269-276, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33899198

RESUMO

BACKGROUND: Bacteremia become fearsome in hematopoietic stem cell transplant (HSCT) recipients with the emergence of multidrug-resistant (MDR) strains. AIM: Our purpose was to investigate the prevalence of MDR bacteremia in HSCT recipients at the Tunisian National Bone Marrow Transplant Center, associated factors and attributable mortality rate. METHODS: Our retrospective study (January 2010-December 2017) included all MDR bacteremia in the Hematology department. MDR rods were: extended spectrum beta-lactamase producing Enterobacterales (ESBL-E), P. aeruginosa and A. baumannii resistant to at least three families of antibiotics, methicillin-resistant S. aureus (MRSA) and vancomycin resistant E. faecium (VRE). RESULTS: The prevalence of MDR bacteremia among HSCT recipients was 5.9% (48/816) with a stable trend over time (rs=0.18). Neutropenia, prior hospitalization, prior antibiotherapy and prior colonization with MDR pathogens were observed in 59%, 58%, 48% and 31% of cases, respectively. Imipenem was the most prescribed first-line antibiotic (50%). The attributable mortality rate was 13%. MDR bacteria (n=48) belonged to ESBL-E (60%), P. aeruginosa (19%), A. baumannii (13%), MRSA (4%) and VRE (4%). For ESBL-E and P. aeruginosa, the rates of antibiotic resistance were respectively, 17% and 44% to imipenem, 31% and 56% to amikacin and 15% and 0% to colistin. Strains of A. baumannii were susceptible only to colistin. The MRSA (n=2) were resistant to ciprofloxacin and gentamicin and susceptible to glycopeptides. The VRE (n=2) were susceptible to linezolid and tigecycline. CONCLUSION: Low prevalence of MDR bacteremia in HSCT recipients but high attributable mortality rate, requiring reinforcement of hygiene measures.


Assuntos
Bacteriemia , Transplante de Células-Tronco Hematopoéticas , Staphylococcus aureus Resistente à Meticilina , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Bacteriemia/epidemiologia , Farmacorresistência Bacteriana Múltipla , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Testes de Sensibilidade Microbiana , Estudos Retrospectivos
11.
J Spinal Cord Med ; 44(2): 282-287, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-31012811

RESUMO

Objective: To report a series of Granulomatous Spondylodiscitis (GS) with focus on the histopathological features of the different forms of GS.Design: Case series.Setting: Pathology department of Charles Nicolle's Hospital of TunisiaParticipants: This study included 57 patients diagnosed with GS. There were 44 (77.2%) female patients and 13 (22.8%) male patients (sex ratio = 0.28).Intervention: Not applicable.Outcome measures: Clinical, microbiological and histopathological features were assessed in this study.Results: Fifty-seven patients with GS were enrolled: 51 tuberculous spondylodiscitis (TS), 2 fungal spondylodiscitis (FS), 3 brucellar spondylodiscitis (BS) and 1 case of sarcoidosis. Granulomas with necrosis were seen in 38 (66.6%) cases: 36 TS and 2 FS, while granulomas without necrosis were observed in the remaining 19 cases: 15 TS, 3 BS and 1 sarcoidosis. In all cases of TS, granulomas were epithelioid type, associated with histiocytic type granulomas in 7 cases. Caseous necrosis was seen in 35 cases of TS and suppurative granuloma in one case. The 3 cases of BS exhibited non-necrotizing and histiocytic type granulomas. The 2 cases of FS showed histiocytic, epithelioid and necrotizing granulomas. Necrosis was mixed: suppurative and caseous in both cases of FS. Sarcoidosis was characterized with epithelioid type granulomas without necrosis.Conclusion: Granuloma with caseous necrosis is highly suggestive of TS but does not rule out FS. Certain fungi can exhibit this type of necrosis as do tuberculosis species. Suppurative inflammation, although rare in TS, does exist. Histiocytic type granuloma without necrosis is suggestive of brucellosis.


Assuntos
Discite , Sarcoidose , Traumatismos da Medula Espinal , Tuberculose , Discite/diagnóstico , Feminino , Granuloma/diagnóstico , Granuloma/etiologia , Humanos , Masculino
13.
Tunis Med ; 99(5): 552-559, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35244905

RESUMO

INTRODUCTION: Healthcare-associated infections (HAIs) are with high rates of mortality and an additional cost, in onco-hematology patients. AIM: To assess the prevalence trends of HAIs in the onco-hematology ward of the Tunisian National Bone Marrow Transplant Center (NBMTC), and to determine the principal associated risk factors. METHODS: Six repeated point prevalence surveys were conducted, from May 2018 to March 2019, using a two months interval. All patients hospitalized in the day of the survey were included. Risk factors of HAIs were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). They were assessed using a logistic regression model. RESULTS: Nineteen patients out of a total of 74 patients have been diagnosed with 19 HAIs, representing a prevalence of 25.7%. No significant downward or upward trend of prevalence was revealed over time (p=0.3). The most common HAI was respiratory tract infection (57.9%) with a prevalence of 14.9%. Multiple logistic regression analysis revealed that HAI was significantly associated with neutropenia (Adjusted OR: 14; 95% CI: 1.5-127; p=0.01) and duration of central venous catheter (Adjusted OR: 1.1; 95% CI: 1-1.2; p=0.005). CONCLUSION: High prevalence of HAIs in our center with a high rate of mortality, requiring identifying potential problems in infection control practices.


Assuntos
Infecção Hospitalar , Hematologia , Infecção Hospitalar/epidemiologia , Atenção à Saúde , Hospitais , Humanos , Prevalência
14.
Acta Microbiol Immunol Hung ; 67(4): 222-227, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33216011

RESUMO

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.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Unidades de Queimados , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , beta-Lactamases/biossíntese , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Colistina/farmacologia , Infecção Hospitalar/epidemiologia , Surtos de Doenças , Genes Bacterianos , Humanos , Tunísia/epidemiologia , beta-Lactamases/genética
15.
J Clin Neurosci ; 78: 360-364, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32418812

RESUMO

Brucellar spondylodiscitis (BS) is the most common form of musculoskeletal brucellosis. The isolation of Brucella spp from blood, other body fluids or tissue cultures is the gold standard for definitive diagnosis of BS. BS shows a large histopathological spectrum of lesions with non-specific and granulomatous forms, and its histopathological features are not widely reported. This case series study reported the histopathological features of a series of 21 BS. Ten cases revealed nonspecific forms of BS. Lymphocytes were the predominant inflammatory cells in this group. In one case neutrophils were predominant. The eleven remaining were granulomatous. The 11 exhibited histiocytic type granulomas. Ten were non-necrotizing. One case, taken from abscess wall, contained minimal deposition of caseous like necrotic material. This case and 2 others corresponding to abscess wall biopsies, showed histiocytic granulomas mixed with small aggregates of epithelioid cells without well-formed epithelioid granuloma nor giant cell. The histopathological diagnosis of BS is challenging. Nonspecific forms of BS, mimiking pyogenic spondylodiscitis, are observed in about half of the cases. Although nonspecific forms of BS are characterized by the predominance of lymphocytes and plasmocytes, BS forms with predominant neutrophil cell infiltration do exist. Histiocytic granuloma is highly suggestive of BS. Purely epithelioid forms of BS were not observed in the present series. Caseous like necrosis suggestive of tuberculosis is a possible feature of BS.


Assuntos
Brucelose/complicações , Discite/microbiologia , Brucella/patogenicidade , Brucelose/diagnóstico , Brucelose/patologia , Discite/etiologia , Discite/patologia , Feminino , Granuloma/patologia , Humanos , Linfócitos/patologia , Masculino , Necrose , Neutrófilos/patologia , Tuberculose
16.
J Clin Rheumatol ; 26(2): 63-66, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32073517

RESUMO

BACKGROUND: Tuberculous spondylodiscitis (TS) is the most common form of musculoskeletal tuberculosis. Currently, histology is widely used to distinguish tuberculous from nontuberculous disease. OBJECTIVES: The aim of the present study was to assess the accuracy of histology compared with bacteriology in the diagnosis of TS. METHODS: This is a single-center case series carried out from January 2014 to February 2018 in a pathology department. It included 121 discovertebral biopsies of infective spondylodiscitis. The measures of diagnostic accuracy of histology were determined taking bacteriology as criterion standard. RESULTS: Among the 121 cases, 55 (45.4%) were diagnosed as TS by histological and/or bacteriological findings, 17 (30.9%) were classified as definite TS by bacteriology, and the remaining 38 (69.1%) had positive histology and negative bacteriology. There were 2 false-negatives, which histologically displayed suppuration without granuloma, and 3 false-positives; in one case, histology displayed granulomas without necrosis and culture isolated Brucella. In the 2 others, histology revealed granulomas with caseous-like necrosis and microbiology isolated fungal species. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of histology in the diagnosis of TS were 88.2%, 93.4%, 83.3%, 95.5%, and 92%, respectively. CONCLUSIONS: Histology is proved to be an accurate diagnostic tool in TS. Suppurative forms of TS without granuloma are rare and represent the main cause of false-negative histology. Suggestive histology of TS does not rule out fungal and brucellar spondylodiscitis. Caseous necrosis is not pathognomonic of tuberculosis. Fungal infection can also exhibit such type of necrosis.


Assuntos
Discite , Tuberculose , Discite/diagnóstico , Granuloma , Humanos , Necrose , Valor Preditivo dos Testes
17.
Polymers (Basel) ; 11(3)2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30960422

RESUMO

In this study, the synthesis of poly(ethylene furanoate) (PEF), catalyzed by five different catalysts-antimony acetate (III) (Sb Ac), zirconium (IV) isopropoxide isopropanal (Zr Is Ip), antimony (III) oxide (Sb Ox), zirconium (IV) 2,4-pentanedionate (Zr Pe) and germanium (IV) oxide (Ge Ox)-via an industrially common combination of melt polymerization and subsequent solid-state polymerization (SSP) is presented. In all reactions, proper amounts of 2,5-dimethylfuran-dicarboxylate (DMFD) and ethylene glycol (EG) in a molar ratio of DMFD/EG= 1/2 and 400 ppm of catalyst were used. Polyester samples were subjected to SSP procedure, under vacuum application, at different reaction times (1, 2, 3.5, and 5 h) and temperatures of 190, 200, and 205 °C. Carboxyl end-groups concentration (⁻COOH), intrinsic viscosity (IV), and thermal properties, via differential scanning calorimetry (DSC), were measured for all resultant polymers to study the effect of the used catalysts on the molecular weight increase of PEF during SSP process. As was expected, it was found that with increasing the SSP time and temperature, the intrinsic viscosity and the average molecular weight of PEF steadily increased. In contrast, the number of carboxyl end-groups content showed the opposite trend as intrinsic viscosity, that is, gradually decreasing during SSP time and temperature increase. It is worthy to note that thanks to the SSP process an obvious and continuous enhancement in the thermal properties of the prepared PEF samples was attained, in which their melting temperatures (Tm) and degree of crystallinity (Xc) increase progressively with increasing of reaction time and temperature. To predict the time evolution of polymers IV, as well as the hydroxyl and carboxyl content of PEF polyesters during the SSP, a simple kinetic model was developed. From both the theoretical simulation results and the experimental measurements, it was demonstrated that surely the Zr Is Ip catalyst shows the best catalytic characteristics compared to all other used catalysts herein, that is, leading in reducing-in a spectacular way-the activation energy of the involved both transesterification and esterification reactions during SSP.

18.
Int J Antimicrob Agents ; 52(6): 861-865, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30176353

RESUMO

The aim of this retrospective study was to investigate the resistance determinants and genetic relatedness of colistin-resistant Klebsiella pneumoniae (ColR-Kp) isolates in the National Bone Marrow Transplant Center of Tunis (NBMTC) between 2002 and 2013. Minimum inhibitory concentrations (MICs) for colistin of ColR-Kp isolates were assessed using a UMIC broth microdilution kit. All isolates were screened by PCR for the resistance genes mcr-1, blaCTX-M-1, blaSHV, blaTEM, blaOXA-1, blaOXA-48, blaKPC, blaIMP, blaVIM, blaNDM, blaGES, blaIMI and blaAmpC as well as class 1, 2 and 3 integrons. The clonality of ColR-Kp isolates was investigated by pulsed-field gel electrophoresis (PFGE). A total of 24 non-duplicate ColR-Kp isolates were collected with MICs ranging from 16 mg/L to >64 mg/L, representing 3.4% (24/709) of the total K. pneumoniae isolates. The colistin resistance gene mcr-1 was not found. The blaSHV gene was present in all of the isolates, blaTEM in 18 isolates, blaCTX-M-1 and blaOXA-1 in 15 isolates each and blaCMY-16 in two isolates. The blaOXA-48 gene was found in five carbapenem-resistant isolates and was associated with blaCTX-M-1, blaSHV, blaTEM and blaOXA-1. All isolates were negative for the remaining carbapenemases. Class 1 integron was found in 19 isolates. PFGE showed non-clonal spread of ColR-Kp isolates in this center. The increasing rate of colistin resistance in K. pneumoniae isolates in NBMTC was neither associated to clonal diffusion nor to the plasmid-mediated colistin resistance gene mcr-1. Its association with the use of colistin in total digestive decolonization in transplant patients at NBMTC must be investigated.


Assuntos
Antibacterianos/farmacologia , Colistina/farmacologia , Farmacorresistência Bacteriana , Hospedeiro Imunocomprometido , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Eletroforese em Gel de Campo Pulsado , Genes Bacterianos , Variação Genética , Humanos , Integrons , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Tipagem Molecular , Plasmídeos/análise , Reação em Cadeia da Polimerase , Estudos Retrospectivos , Tunísia/epidemiologia
19.
Int J Antimicrob Agents ; 52(6): 886-892, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29783023

RESUMO

BACKGROUND: Extended spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) create a therapeutic challenge and have high potential for dissemination. The purpose of our study was to investigate the epidemiology of these infections in hematopoietic stem cell transplant (HSCT) recipients and to determine the genes encoding ESBL. MATERIAL/METHODS: This retrospective study comprised adult patients hospitalized at the National Bone Marrow Transplant Center (NBMTC) and infected with ESBL-E post-HSCT between January 2006 and December 2016. The search for the ESBL and carbapenemase genes was performed by polymerase chain reaction (PCR) amplification. Molecular typing was performed by pulsed field gel electrophoresis (PFGE) after digestion with XbaI. RESULTS: Forty ESBL-E were responsible for infections in 34 HSCT recipients (3.3% of total HSCT recipients). Prior hospital stay, prior antibiotic therapy and prior colonization with ESBL-E were reported in 62.5%, 70% and 50% of the infectious episodes, respectively. The initial antibiotic treatment was appropriate in 67.7% of cases. Imipenem was the most prescribed antibiotic (64.5%). The mortality rate due to ESBL-E infection was 8.8%. The ESBL-E, isolated mainly from blood cultures (40%), belonged mostly to K. pneumoniae (n=19) and E. coli (n=17). Associated antibiotic resistance rates were 17.5% for ertapenem, 85% for ciprofloxacin and 30% for amikacin. The predominant gene encoding ESBL was blaCTX-M (55%). Among the seven carbapenem-resistant strains, four had the blaOXA-48 gene and two the blaKPC gene. There was no clonal relationship between the strains. CONCLUSION: There was low prevalence of ESBL-E infections in HSCT recipients in our center, with no epidemic distribution but non-negligible mortality rate.


Assuntos
Infecções por Enterobacteriaceae/epidemiologia , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/enzimologia , Enterobacteriaceae/isolamento & purificação , Transplante de Células-Tronco Hematopoéticas , beta-Lactamases/genética , Adolescente , Adulto , Eletroforese em Gel de Campo Pulsado , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/mortalidade , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Tipagem Molecular , Reação em Cadeia da Polimerase , Prevalência , Estudos Retrospectivos , Análise de Sobrevida , Adulto Jovem
20.
Int J Antimicrob Agents ; 52(6): 893-897, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29698665

RESUMO

OBJECTIVES: Macrolide-resistant Streptococcus pneumoniae isolates have increased considerably in the last decade, with important geographical variations in involved phenotypes and genotypes. The aim of this study was to investigate phenotypes, genotypes, serotypes and genetic relatedness of macrolide-resistant S. pneumoniae isolated from immunocompromised patients in Tunisia. METHODS: Antibiotic susceptibility was determined by disk diffusion, and MICs of erythromycin and clindamycin were determined for macrolide-resistant isolates by Etest. Macrolide-resistant isolates were analysed by PCR for ermB, mefA, tetM, tetO and Int-Tn1545. Serotyping was done by multiplex PCR and the Quellung reaction. Multilocus sequence typing (MLST) was performed for molecular typing. RESULTS: Macrolide resistance was observed in 41 (69.5%) of 59 isolates. Of the 41 isolates, 37 (90.2%) had a macrolide-lincosamide-streptogramin B (MLSB) resistance phenotype, with a predominance of high-level inducible MLSB phenotype, and harboured the ermB gene. All isolates with high-level inducible MLSB phenotype were highly resistant to erythromycin and clindamycin. Four isolates (9.8%) had a macrolide (M) resistance phenotype and harboured the mefA gene. Erythromycin-resistant isolates were multidrug-resistant (MDR) in 97.5% of cases and extensively drug-resistant in 12.2%. The isolates belonged essentially to four serotypes (19F, 23F, 14 and 6B). They were mainly assigned to three sequence types (ST81, ST2918 and ST386). Also, 65.9% of the isolates were grouped in three clonal complexes (CC81, CC838 and CC386). CONCLUSIONS: These data indicate a high prevalence of Tn1545 transposon and of three MDR international clones contributing to the high frequency of multidrug resistance among S. pneumoniae isolates in our centre.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Hospedeiro Imunocomprometido , Macrolídeos/farmacologia , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/microbiologia , Streptococcus pneumoniae/efeitos dos fármacos , Elementos de DNA Transponíveis , Genes Bacterianos , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase , Prevalência , Sorogrupo , Sorotipagem , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/isolamento & purificação , Tunísia/epidemiologia
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