Background Streptococcus pneumoniae remains a leading cause of morbidity and mortality worldwide. In this study, we sought to analyze serotype distributions, antibiotic resistance, and genetic relationships of 106 clinical invasive... more
Background Streptococcus pneumoniae remains a leading cause of morbidity and mortality worldwide. In this study, we sought to analyze serotype distributions, antibiotic resistance, and genetic relationships of 106 clinical invasive pneumococcal isolates recovered in Tunisia between 2012 and 2018, prior to the routine use of pneumococcal conjugate vaccines (PCV). Methods We used multiplex PCR, the disk diffusion method and/or E-test, and multi-locus sequence typing (MLST). Results The most frequent serotypes were 14 (17%), 19F (14.2%), and 3 (11.3%). Of the 106 S. pneumoniae isolates, 67.9% were penicillin non-susceptible (29.4% were resistant), 45.3% were amoxicillin non-susceptible (17% were resistant), and 16% were cefotaxime non-susceptible. For antibiotics other than β-lactams, resistance rates to erythromycin, tetracycline, cotrimoxazole, and chloramphenicol were 62.3, 33, 22.6, and 4.7%, respectively. Two isolates were non-susceptible to levofloxacin. Among 66 erythromycin-res...
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Streptococcus pneumoniae remains a significant cause of morbidity and mortality worldwide despite the overall success of the vaccine programs. In Tunisia, pneumococcal conjugate vaccines (PCV)10 was introduced in the national immunization... more
Streptococcus pneumoniae remains a significant cause of morbidity and mortality worldwide despite the overall success of the vaccine programs. In Tunisia, pneumococcal conjugate vaccines (PCV)10 was introduced in the national immunization program in April 2019. We sought to determine the relationship between serotypes and antimicrobial nonsusceptibility of S. pneumoniae isolates recovered from clinical samples in the prevaccination period in the south of Tunisia. A total of 504 nonduplicate S. pneumoniae isolates collected between 2012 and 2018 were tested for antimicrobial susceptibility, among them 439 (87.1%) were serotyped. The most common serotypes were 19F (17.8%), 14 (15.3%), 3 (9.1%), 19A (8.2%), and 23F (7.3%). The proportions of isolates with serotypes covered by PCV7, PCV10, and PCV13 were 55.4%, 56.3%, and 77.9%, respectively. Three-quarters (74.4%) of pneumococcal isolates were nonsusceptible to penicillin, and about half (54.8%) were multidrug resistant. Penicillin nonsusceptibility was observed for all 19A and 23F isolates, and was significantly associated with serotypes 19F (odds ratio [OR]: 33.7) and 14 (OR: 8.7). A significant association with multidrug resistance was noted for serotypes 19A (OR: 10), 19F (OR: 9.4), 23F (OR: 8.6), and 6B (OR: 5.2). The alarming rates of pneumococcal antimicrobial nonsusceptibility and the strong association with the most prevalent serotypes compel microbiologists to monitor the impact of the PCV10 introduced recently in our national immunization program.
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INTRODUCTION Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin... more
INTRODUCTION Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin resistant (Optr) S. pneumoniae identification is essential. METHODOLOGY Atypical pneumococci were characterized using optochin susceptibility, bile solubility based on spectrophotometric reading, serotyping, pulsed field gel electrophoresis (PFGE), 16S rRNA sequencing and PCR-based assays targeting pneumococcal genes lytA, ply, pspA, cpsA, Spn9802 and Spn9828. RESULTS Optical density values for the bile solubility test suggest the identification of four Optr S. pneumoniae and one Streptococcus pseudopneumoniae. All Optr pneumococci harbored cpsA, lytA, ply, Spn9802, Spn9828 and pspA genes. Only ply, spn9802 and Spn9828 genes were detected in S. pseudopneumoniae. The 16S rRNA sequencing differentiates between these two species. Optr S. pneumoniae st...
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But: Typage des souches de Serratia marcescens responsables d'infections nosocomiales dans le service de reanimation de Sfax (Tunisie). Methodes: L'electrophorese en champ pulse a ete appliquee pour determiner la clonalite des... more
But: Typage des souches de Serratia marcescens responsables d'infections nosocomiales dans le service de reanimation de Sfax (Tunisie). Methodes: L'electrophorese en champ pulse a ete appliquee pour determiner la clonalite des souches. Il s'agit de 56 souches de Serratia marcescens isolees chez des malades hospitalises dans le service de reanimation de Sfax durant les annees 2003 et 2004. Sept souches de Serratia marcescens isolees durant la meme periode en dehors du service de reanimation ont ete incluses dans l'etude comme souches controles. Des prelevements dans l'environnement hospitalier et chez le personnel ont ete realises a la recherche d'une source de contamination. Resultats: Toutes les souches ont presente un phenotype sauvage vis-a-vis des ,-lactamines. L'application de l'electrophorese en champ pulse a montre la presence de trois clones differents. Les explorations bacteriologiques pour la recherche de la source de contamination etaient n...
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Research Interests: Genetics, Microbiology, Medical Microbiology, Biology, Medicine, and 15 moreMolecular Epidemiology, Humans, Female, Animals, Male, Antimicrobial chemotherapy, Aged, Integrons, Genotype, Microbial Sensitivity Tests, Azithromycin, Allele, Neisseria gonorrhoeae, Beta Lactamases, and Multilocus sequence typing
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This study was conducted to identify the β-lactamase content of 30 metallo-β-lactamase-producing Pseudomonas aeruginosa isolated in 2007 from two Tunisian hospitals and to investigate their genetic relatedness. All these isolates produced... more
This study was conducted to identify the β-lactamase content of 30 metallo-β-lactamase-producing Pseudomonas aeruginosa isolated in 2007 from two Tunisian hospitals and to investigate their genetic relatedness. All these isolates produced VIM-2. bla(PER-1), bla(PSE-1), bla(OXA-2), and bla(OXA-10) were identified in 17, 5, 21, and 1 isolates, respectively. These enzymes were often associated in the same isolate: 26 isolates had at least two β-lactamases. The predominant serotype was O12. Pulsed-field gel electrophoresis revealed genetic diversity among the metallo-β-lactamase-producing P. aeruginosa isolates. This is the first report on the existence of bla(PER-1), bla(PSE-1), bla(OXA-2), and bla(OXA-10) in Tunisia.
Research Interests: Microbiology, Biology, Medicine, Genetic Diversity, Biological Sciences, and 11 moreHumans, Tunisia, Pseudomonas aeruginosa, Anti-Bacterial Agents, Pulsed field gel electrophoresis (PFGE), Microbial Sensitivity Tests, Pseudomonas Aeruginosa, Beta Lactamases, microbial drug resistance, Serotype, and Medical and Health Sciences
Eighty-four isolates of Salmonella enterica serovar Livingstone were collected from patients hospitalized in a pediatric ward in Sfax Hospital (South Tunisia). These isolates were responsible for two nosocomial outbreaks in 2000 and 2002.... more
Eighty-four isolates of Salmonella enterica serovar Livingstone were collected from patients hospitalized in a pediatric ward in Sfax Hospital (South Tunisia). These isolates were responsible for two nosocomial outbreaks in 2000 and 2002. Twenty-eight clinical isolates of S. enterica serovar Livingstone were also obtained in two other Tunisian hospitals in Monastir (Central Tunisia) and Tunis (North Tunisia), respectively, in 2002 and 2003. Pulsed-field gel electrophoresis yielded that these isolates were closely related. Antimicrobial susceptibility testing showed a particular beta-lactam resistance phenotype, suggestive of the presence of an AmpC-type enzyme in 111 of the 112 clinical isolates. bla(ACC-1) was characterized by polymerase chain reaction (PCR) and sequence analysis in the 111 isolates. TEM-1 was characterized in all strains and SHV-2a in only two strains. The genetic organization of bla(ACC-1) was determined by PCR mapping and sequencing. The plasmid-borne bla(ACC-1) gene mapped immediately downstream from ISEcp1. This ISEcp1 insertion sequence was itself disrupted by IS26 insertion sequences. A supplementary deletion of 13 bp was observed in ISEcp1 upstream IS26, in all isolates from Tunis, except one. PCR analysis and sequencing also revealed the presence of tnpR, bla(SCO-1), gdha, IS1353, and TniB Delta 1.
Research Interests: Genetics, Microbiology, Biology, Medicine, Hospitals, and 15 moreMolecular Epidemiology, Biological Sciences, Disease Outbreaks, Humans, Polymerase Chain Reaction, Salmonella, Insertion sequence, Microbial Sensitivity Tests, Base Sequence, Outbreak, Plasmid, Beta Lactamases, microbial drug resistance, Molecular Sequence Data, and Medical and Health Sciences
We characterized 67 Escherichia coli isolates with reduced susceptibility to cefotaxime obtained from 136 samples of healthy broilers housed in 36 Tunisian farms. All these isolates harboured bla(CTX-M-1) and/or bla(CMY-2) genes located... more
We characterized 67 Escherichia coli isolates with reduced susceptibility to cefotaxime obtained from 136 samples of healthy broilers housed in 36 Tunisian farms. All these isolates harboured bla(CTX-M-1) and/or bla(CMY-2) genes located mostly on self-conjugative IncI1 plasmids. qnrS1, qnrA6 and aac(6')-Ib-cr were detected in six isolates. Considerable genetic diversity was detected among isolates from different farms. To our knowledge, this is the first detailed documentation of a high occurrence of bla(CTX-M-1) and bla(CMY-2) in E. coli at the poultry farm level in Tunisia as well as the first description of plasmid-mediated quinolone resistance in food animals in Tunisia which may contribute to the dissemination of these genes throughout Tunisia. Significance and Impact of the Study: This study is the first detailed documentation of a high occurence of extended-spectrum β-lactamases and plasmidic cephalosporinases in E. coli at the poultry farm level in Tunisia. Moreover, this is the first description of plasmid-mediated quinolone resistance (PMQR) in Tunisian animals. This study highlights that Tunisian poultry are a reservoir of antibiotic resistance genes which may be transferred to humans.
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Research Interests: Microbiology, Medical Microbiology, Horizontal Gene Transfer, Medicine, Humans, and 12 moreTunisia, Klebsiella, Antimicrobial chemotherapy, Anti-Bacterial Agents, Beta Lactams, Microbial Sensitivity Tests, University Hospitals, Beta Lactamases, Klebsiella pneumoniae, beta-Lactam Resistance, Pharmacology and pharmaceutical sciences, and Cross Infection
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Klebsiella pneumoniae clinical isolates resistant to carbapenems were recovered from 11 patients in the hospital of Sfax, Tunisia. The isolates were closely related as shown by pulsed-field gel electrophoresis, and they produced VIM-4... more
Klebsiella pneumoniae clinical isolates resistant to carbapenems were recovered from 11 patients in the hospital of Sfax, Tunisia. The isolates were closely related as shown by pulsed-field gel electrophoresis, and they produced VIM-4 metallo-enzyme, CTX-M-15 extended-spectrum β-lactamase, and CMY-4 AmpC enzyme. The bla VIM-4 gene is part of a class 1 integron.