Group B Streptococcus and Perinatality in the South of Tunisia: Epidemiology, Serotype Distribution, and Antibiotic Susceptibility.

INTRODUCTION: In the lack of updated Tunisian epidemiological data, we sought to describe the epidemiology of Group B Streptococcus (GBS) in pregnant women and newborns. MATERIALS AND METHODS: A retrospective analysis of GBS neonatal invasive infections and a cross-sectional study evaluating the prevalence of maternal GBS colonization were conducted. GBS isolates were tested for antimicrobial susceptibility, serotyped, and assessed for the appurtenance to the hypervirulent ST17 clone. RESULTS: Of 98 neonates with GBS, early-onset GBS disease (EOD) comprised 83.7 and 16.3% were late-onset GBS disease (LOD). The prevalence of maternal GBS colonization was 27%. All GBS isolates were susceptible to penicillin. Serotype III predominated (42.6%) for neonatal invasive infections. GBS isolates belonging to the ST17 sequence type were found only as serotype III. CONCLUSION: This study documents the frequency of GBS EOD, the high rate of maternal GBS colonization, and the predominance of the hypervirulent clone type III/ST17 in infants.

Antibiotic resistance pattern, capsular types, and molecular characterization of invasive isolates of Streptococcus pneumoniae in the south of Tunisia from 2012 to 2018.

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 ß-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-resistant pneumococci, 77.3% exhibited the cMLSB phenotype, and 87.9% carried ermB gene. All tetracycline-resistant strains harbored the tetM gene. The potential coverage by 7-, 10-, and 13-valent pneumococcal conjugate vaccines were 55.7, 57.5, and 81.1%, respectively. A multilocus sequence typing analysis revealed great diversity. Fifty different sequence types (STs) were identified. These STs were assigned to 10 clonal complexes and 32 singletons. The most common STs were 179, 2918, 386, and 3772 - related mainly to 19F, 14, 6B/C, and 19A serotypes, respectively. CONCLUSIONS: This study demonstrated that the majority of the serotypes of invasive pneumococci in the Tunisian population were 14, 19F, and 3. Moreover, we noted a high degree of genetic diversity among invasive S. pneumoniae isolates. The highest proportions of antibiotic non-susceptible isolates were for penicillin, erythromycin, and tetracycline. Further molecular characteristics are required to monitor the genetic variations and to follow the emergence of resistant pneumococci for the post-vaccination era in Tunisia.

Trends in human intestinal carriage of ESBL- and carbapenemase-producing Enterobacterales among food handlers in Tunisia: emergence of C1-M27-ST131 subclades, blaOXA-48 and blaNDM.

OBJECTIVES: To determine the prevalence of community intestinal carriage of ESBL-producing Enterobacterales (ESBL-E), acquired-AmpC-producing Enterobacterales (aAmpC-E) and carbapenemase-producing Enterobacterales (CPE) in Tunisia. METHODS: From November 2012 to September 2017, stool samples from food handlers in Sfax, Tunisia, were screened for ESBL-E, AmpC-E and CPE using antibiotic-containing media. The genes encoding these ß-lactamases were characterized by PCR, sequencing, and transfer assays. ST131 clonal groups were detected by PCR and characterized for antibiotic resistance, virulence genes and PFGE patterns. RESULTS: Of 2135 participants, ESBL-E, aAmpC-E, and CPE carriage were detected in 419 (19.63%), 35 (1.63%) and 7 (0.33%) participants, respectively. CTX-M-15 (60%), CTX-M-1 (16.8%) and CTX-M-27 (12.8%) were the most common ESBL determinants. The ESBL-E carriage was significantly higher in summer (33%) and autumn (25.7%) than in winter (12.1%) and spring (11.4%). ST131 was detected in 50 (13.2%) of the 378 ESBL-producing Escherichia coli isolates; most of them (35; 70%) belonged to subclade C1 (cluster C1-M27: 23 isolates, 46%; cluster C1-non-M27: 12 isolates, 24%) followed by those belonging to subclade C2 (11; 22%). Although subclade C2 isolates, all harbouring blaCTX-M-15, had the highest resistance rates and virulence factor and addiction system scores, the subclade C1 isolates, mainly harbouring blaCTX-M-27 (94%), were predominant since 2015. The most frequently detected carbapenemase-encoding gene was blaOXA-48-like (85%) and acquired AmpC-encoding genes were blaDHA-1 (54%) and blaCMY-2 (46%). CONCLUSIONS: This is the first large Tunisian study to reveal a high faecal ESBL carriage rate, a low CPE carriage rate, and the predominance of CTX-M-27-producing subclade C1 among faecal ESBL-ST131 isolates in the Tunisian community.

Comparison of conventional molecular and whole-genome sequencing methods for subtyping Salmonella enterica serovar Enteritidis strains from Tunisia.

We sought to determine the relative value of conventional molecular methods and whole-genome sequencing (WGS) for subtyping Salmonella enterica serovar Enteritidis recovered from 2000 to 2015 in Tunisia and to investigate the genetic diversity of this serotype. A total of 175 Salmonella Enteritidis isolates were recovered from human, animal, and foodborne outbreak samples. Pulsed-field gel electrophoresis (PFGE), multiple locus variable-number tandem repeat analysis (MLVA), and whole-genome sequencing were performed. Eight pulsotypes were detected for all isolates with PFGE (DI = 0.518). Forty-five Salmonella Enteritidis isolates were selected for the MLVA and WGS techniques. Eighteen MLVA profiles were identified and classified into two major clusters (DI = 0.889). Core genome multilocus typing (cgMLST) analysis revealed 16 profiles (DI = 0.785). Whole-genome analysis indicated 660 single-nucleotide polymorphism (SNP) divergences dividing these isolates into 43 haplotypes (DI = 0.997). The phylogenetic tree supported the classification of Salmonella Enteritidis isolates into two distinct lineages subdivided into five clades and seven subclades. Pairwise SNP differences between the isolates ranged between 302 and 350. We observed about 311 SNP differences between the two foodborne outbreaks, while only less or equal to 4 SNP differences within each outbreak. SNP-based WGS typing showed an excellent discriminatory power comparing with the conventional methods such as PFGE and MLVA. Besides, we demonstrate the added value of WGS as a complementary subtyping method to discriminate outbreak from non-outbreak isolates belonging to common subtypes. It is important to continue the survey of Salmonella Enteritidis lineages in Tunisia using WGS.

Development of a new TaqMan-based PCR assay for the specific detection and quantification of Simkania negevensis.

Simkania negevensis is an emerging Chlamydia-like bacterium related to human respiratory diseases. An early and accurate detection of this pathogen could be useful to monitor the potential infectious risks and to set suitable outbreak control measures. In Tunisia, distribution and abundance of S. negevensis remain until now largely unknown. In the present work, a qPCR assay, targeting the 16S rRNA gene, for fast detection and quantification of S. negevensis was developed and validated. A high specificity for S. negevensis detection displaying no cross-reaction with the closely related Chlamydia spp. or the other tested microorganisms was noticed. qPCR assay performance was considered very satisfying with detection limits of 5 DNA copies per reaction. qPCR assay validation was performed by screening 37 clinical specimens and 35 water samples. S. negevensis wasn't detected in respiratory samples, but it was found in four cases of water samples. We suggest that the qPCR assay developed in this study could be considered sufficiently characterized to initiate the quantification of S. negevensis in environmental samples.

Detection of Shigella spp. nucleic acids in the synovial tissue of Tunisian rheumatoid arthritis patients and other forms of arthritis by quantitative real-time polymerase chain reaction.

Enterobacterial components in the joints of patients are believed to contribute to a perpetuating inflammation leading to a reactive arthritis (ReA), a condition in which microbial agents cannot be recovered from the joint. At present, it is unclear whether nucleic acids from Shigella spp. are playing a pathogenic role in causing not only ReA but also other forms of arthritis. Quantitative real-time polymerase chain reaction assay (qPCR) is the method of choice for the identification of bacteria within the synovium. The aim of our study was to detect the presence of Shigella spp. nucleic acids in the synovial tissue (ST) of Tunisian arthritis patients. We investigated 57 ST samples from rheumatoid arthritis (RA) n = 38, undifferentiated oligoarthritis (UOA) n = 12, and spondyloarthritis (SpA) n = 7 patients; 5 ST samples from healthy individuals were used as controls. Shigella spp. DNA and mRNA transcripts encoding the virulence gene A (VirA) were examined using an optimized qPCR with newly designed primers and probes. Using qPCR, Shigella spp. DNA was found in 37/57 (65%) ST samples (24/38, i.e., 63.2% of RA, 8/12, i.e., 67% of UOA, and 5/7, i.e., 71.4% of SpA patients). Paired DNA and mRNA were extracted from 39 ST samples, whose VirA cDNA was found in 29/39 (74.4%) patients. qPCR did not yield any nucleic acids in the five healthy control ST samples. The qPCR assay was sensitive and showed a good intra- and inter-run reproducibility. These preliminary findings generated by an optimized, highly sensitive PCR assay underline a potential role of past gastrointestinal infections. In Tunisian patients, a bacterial etiology involving Shigella spp. in the manifestation of arthritic disorders including RA might be more common than expected.

Detection of Rickettsia in Rhipicephalus sanguineus ticks and Ctenocephalides felis fleas from southeastern Tunisia by reverse line blot assay.

Ticks (n = 663) and fleas (n = 470) collected from domestic animals from southeastern Tunisia were screened for Rickettsia infection using reverse line blot assay. Evidence of spotted fever group Rickettsia was obtained. We detected Rickettsia felis in fleas, Rickettsia massiliae Bar 29 and the Rickettsia conorii Israeli spotted fever strain in ticks, and Rickettsia conorii subsp. conorii and Rickettsia spp. in both arthropods. The sensitivity of the adopted technique allowed the identification of a new association between fleas and R. conorii subsp. conorii species. The presence of these vector-borne Rickettsia infections should be considered when diagnosing this disease in humans in Tunisia.

Chlamydia trachomatis infection increases the expression of inflammatory tumorigenic cytokines and chemokines as well as components of the Toll-like receptor and NF-κB pathways in human prostate epithelial cells.

Inflammation has been reported to play a major role in prostate carcinogenesis. Several bacterial infections can lead to prostate inflammation; however, until now, the precise molecular and cellular mechanisms linking inflammation to carcinogenesis have remained unclear. We therefore investigated the initiation of inflammation induced by Chlamydia trachomatis (C. trachomatis) infection in human prostate epithelial cells using an in vitro culture system in which human androgen-independent PC-3 prostate cancer epithelial cells were infected with C. trachomatis serovar L2. The expression levels of VEGF, ICAM-1, IL-6, IL-8, IL-1ß, TNFα, CCL5, CCL2 and iNOS inflammation-related genes, as well as genes involved in the Toll-like receptor (TLR) pathway (TLR2, TLR4, CD14 and MyD88), were evaluated at the mRNA level in infected PC-3 cells 24 h after infection with C. trachomatis serovar L2. The expression levels of components of the NF-κB pathway (p65 and IκBα) were evaluated at the mRNA level in infected PC-3 cells at different time points (1, 6, 12 and 24 h) after infection. The expression levels of inflammation-related genes, components of the Toll-like receptor pathway and genes involved in NF-κB activation were analyzed in infected and uninfected cells using semi-quantitative RT-PCR. We detected a significant increase (p < 0.001) in inflammation-related cytokines in infected PC-3 cells. During infection, PC-3 cells elicited a proinflammatory response, as shown by NF-κB activation, TLR2 and TLR4 upregulation and the increased expression of inflammation-related genes. Furthermore, we observed significant upregulation of the adhesion molecules ICAM-1 and VEGF, which are two biomarkers correlated with tumor progression and immune system evasion. The present study suggests that human prostate cancer epithelial cells are susceptible to C. trachomatis infection and upregulate proinflammatory markers during infection.

Reliability of the rapid antigen test for diagnosis of SARS-CoV-2 in Tunisia.

Background: Early and accurate diagnosis is crucial for preventing the spread of SARS-CoV-2 infection. The rapid antigen test was developed for testing infection, and it was necessary to assess its performance before widespread use in Tunisia. Aim: To evaluate the effectiveness of a rapid antigen test for the detection of SARS-CoV-2 in nasopharyngeal swabs in Tunisia. Methods: Nasopharyngeal samples were taken from COVID-19 suspected cases between October and December 2020 and tested using the Standard Q COVID-19 Ag test (SD-Biosensor, Republic of Korea) and real-time reverse transcription polymerase chain reaction (RT­PCR). Results: Overall, 4539 patients were tested. Of the total study population (N = 4539), 82.5% of positive samples remained positive with the rapid antigen test, while 20.2% (470/2321) of samples that were negative with rapid antigen test were confirmed positive with RT-PCR, giving a negative predictive value of 79.8% for the rapid antigen test. The sensitivity and negative predictive value of the rapid antigen test were 70.2% and 65.8%, respectively. These results improved to 96.4% and 92.8%, respectively, when considering the cycle threshold value by RT-PCR below 25. Conclusion: Although the rapid antigen test was less sensitive than RT-PCR, its ability to rapidly detect individuals with high viral loads makes it suitable for use during an epidemic.

Assessment of histology's performance compared with PCR in the diagnosis of Helicobacter pylori infection.

Aim: Histology is the most widely used test to detect H. pylori. PCR is less used but allows the detection of both infection and antibiotics' resistance. Methods: We conducted a monocentric cross-sectional study, collecting 97 symptomatic patients to assess the diagnostic performance of histology in the detection of H. pylori infection compared with PCR. Results: Sensitivity of histology in comparison with PCR was 81.5% and specificity was 56.3%. A history of anti-H. pylori therapy intake, as well as the density of the bacterium on the gastric sample and the presence of gastric atrophy, were significantly correlated to the PCR's result in terms of H. pylori detection. Conclusion: Thus, histology can be considered as an efficient test compared with PCR in H. pylori detection.

Helicobacter pylori is a type of bacteria that can cause diseases in the stomach and the upper part of the small intestine. A number of different methods are applied by scientists to determine if this bacterium is present. In our research, we specifically examined the accuracy of two types of tests ­ one where doctors examine tissues under the microscope to find signs of the bacteria (pathological test), and another where they use a method called PCR to find the bacteria's genetic material. Our aim was to determine which test worked better.

Nasopharyngeal Carriage of Streptococcus pneumoniae in Tunisian Healthy under-Five Children during a Three-Year Survey Period (2020 to 2022).

We aimed to assess the prevalence of nasopharyngeal pneumococcal carriage and to determine serotype distribution, antibiotic susceptibility patterns, and evolutionary dynamics of Streptococcus pneumoniae isolates in healthy under-five children. Nasopharyngeal swabs were collected from healthy children over three survey periods between 2020 and 2022. All pneumococcal isolates were serotyped and tested for antimicrobial susceptibility. A total of 309 S. pneumoniae isolates were collected, with an overall prevalence of nasopharyngeal pneumococcal carriage of 24.4% (CI95%: [22-26.8%]). These isolates were classified into 25 different serotypes. The most common serotypes were 14 (14.9%), 19F (12%), 6B (10.4%), and 23F (7.4%), which are covered by the PCV10 vaccine, as well as 19A (8.4%) and 6A (7.8%), which are covered by the PCV13 vaccine. A significant decrease in the proportion of serotype 19F (p = 0.001) and an increase in serotypes 19A (p = 0.034) and 6A (p = 0.029) were observed between the three survey periods. Multidrug resistance (MDR) was noted for 56.6% of the isolates. A significant association with antimicrobial resistance was observed for the most frequent serotypes, mainly serotype 19A. In conclusion, one-quarter of healthy under-five children in Tunisia carried S. pneumoniae in their nasopharynx. A dominance of vaccine serotypes significantly associated with antimicrobial resistance was recorded.

Carbapenem- and colistin-resistant Enterobacterales in intensive care unit patients in Mediterranean countries, 2019.

Introduction: The colonization of patients by carbapenemase-producing Enterobacterales (CPE) has been associated with heightened mortality, especially in vulnerable individuals within intensive care units (ICUs). Our study aimed to comprehensively assess CPE prevalence among ICU patients across the Mediterranean region pre-COVID-19, conducting a multicenter prevalence study in the first quarter of 2019. Methods: We collected clinical data and rectal or fecal samples from 256 ICU patients for CPE testing. Additionally, we performed whole-genome sequencing on 40 representative CPE strains to document their molecular characteristics. Results: Among the 256 patients, CPE was detected in 73 samples (28.5%), with prevalence varying from 3.3 to 69.0% across participating centers. We observed 13 colistin-resistant CPE strains, affecting three ICUs. Genetic analysis revealed highly diverse E. coli and K. pneumoniae strains, predominantly from international high-risk clones. Notably, blaOXA-48 and blaNDM-1 were the most prevalent carbapenemase genes. Molecular typing uncovered potential patient clusters in six centers. Significantly, longer hospital stays were associated with increased CPE carriage (p < 0.001). Nine centers across Morocco, Tunisia, Egypt, and Lebanon voluntarily participated. Discussion: Our study provides CPE prevalence in Mediterranean ICUs and reaffirms established CPE presence in this setting but also provides updates on the molecular diversity of CPE strains. These findings highlight the imperative of reinforcing infection control measures in the participating ICUs to curtail escalated mortality rates, and of strictly applying isolation measures around patients originating from the Mediterranean region when transferred to other healthcare institutions.

Molecular epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli in Tunisia and characterization of their virulence factors and plasmid addiction systems.

BACKGROUND: Extended-spectrum ß-lactamases (ESBLs), particularly CTX-M- type ESBLs, are among the most important resistance determinants spreading worldwide in Enterobacteriaceae. The aim of this study was to characterize a collection of 163 ESBL-producing Escherichia coli collected in Tunisia, their ESBL-encoding plasmids and plasmid associated addiction systems. RESULTS: The collection comprised 163 ESBL producers collected from two university hospitals of Sfax between 1989 and 2009. 118 isolates harbored blaCTX-M gene (101 blaCTX-M-15 gene and 17 blaCTX-M-14 gene). 49 isolates carried blaSHV-12 gene, 9 blaSHV-2a gene and only 3 blaTEM-26 gene. 16 isolates produced both CTX-M and SHV-12. The 101 CTX-M-15-producing isolates were significantly associated to phylogroup B2 and exhibiting a high number of virulence factors. 24 (23.7%) of the group B2 isolates belonged to clonal complex ST131. Pulsed-field gel electrophoresis (PFGE) typing revealed a genetic diversity of the isolates. 144 ESBL determinants were transferable mostly by conjugation. The majority of plasmid carrying blaCTX-M-15 genes (72/88) were assigned to various single replicon or multireplicon IncF types and had significantly a higher frequency of addiction systems, notably the VagCD module. CONCLUSION: This study demonstrates that the dissemination of CTX-M-15 producing E. coli in our setting was due to the spread of various IncF-type plasmids harboring multiple addiction systems, into related clones with high frequency of virulence determinants.

Significant impact of COVID-19 pandemic on the circulation of respiratory viruses in Tunisia, 2020-2021.

Background: The COVID-19 pandemic changed the typical patterns of respiratory infections globally. While SARS-CoV-2 illness exhibited explosive growth since 2020, the activity of other respiratory viruses fell below historical seasonal norms. The objective of this study was to assess the prevalence of seasonal respiratory viruses during the COVID-19 pandemic in Tunisia. Methods: This is a retrospective cross-sectional study including 284 nasopharyngeal samples tested negative for SARS-CoV-2 during the period October 2020-May 2021. All samples were screened for fifteen common respiratory viruses. Either a fast syndromic approach using Biofire FILM ARRAY respiratory 2.1 (RP2.1) Panel, or end-point multiplex RT-PCRs detecting RNA viruses and Real-Time PCR detecting Adenoviruses were used. Results: Overall, 30.6% (87/284) of samples were positive for at least one virus. Mixed infections were detected in 3.4% of positive cases. Enterovirus/Rhinovirus (HEV/HRV) was the most detected virus throughout the study period, especially during December 2020 (33.3% of all HEV/HRV being detected). During the 2020-2021 winter season, neither Respiratory Syncytial Virus nor Influenza Viruses circulation was observed. Metapneumovirus and Parainfluenza Viruses infections were detected during the spring season. The highest rate of respiratory viruses detection was observed in children and adults aged [0-10] years (50%) and [31-40] years (40%). HEV/HRV was the most detected virus regardless of age group. Conclusions: Public health measures used to prevent SARS-CoV-2 spread in Tunisia were also effective to reduce transmission of the other respiratory viruses, especially Influenza. The higher resistance of HEV/HRV in the environment could explain their predominance and continuous circulation during this period.

Large spontaneous HBV DNA fluctuations and potential usefulness of a single-point measurement of combined HBV DNA and quantitative HBsAg for the exclusion of HBeAg-negative chronic hepatitis B: A prospective Tunisian cohort study.

BACKGROUND AND STUDY AIM: During the natural course of HBeAg-negative chronic hepatitis B (CHB), fluctuations in hepatitis B virus (HBV) DNA and alanine aminotransferase (ALT) levels are often observed, making the classification of patients difficult. We aimed to describe spontaneous short-term HBV DNA level fluctuations and to assess the usefulness of qHBsAg in Tunisian patients with HBeAg-negative chronic HBV infection. PATIENTS AND METHODS: We included 174 treatment-naive Tunisian patients with HBeAg-negative chronic HBeAg-negative HBV infection. A prospective 1-year follow-up was conducted with serial determinations of HBV DNA, ALT levels, and qHBsAg. The patients were classified into three groups: inactive carriers (G1), patients with negative HBeAg CHB (G2), and patients with an "indeterminate state" (G3). For the latter group, a liver biopsy was indicated. RESULTS: Only genotype D was detected. During follow-up, 21.6% and 19.5% of patients with a low initial (<2,000 IU/ml) and intermediate viral load (2,000-20,000 IU/ml) experienced a subsequent increase in their HBV DNA levels above 2,000 and 20,000 IU/ml, respectively. Significant variations in viral load were observed in 61.1% of patients at 6-month intervals. Among the 174 patients, 89 (51.1%) belonged to G1, 33 (19%) to G2, and 52 (29.9%) to G3. Fourteen patients have undergone a liver biopsy, of whom seven showed moderate to severe liver disease. Combination of HBV DNA < 2,000 IU/ml and qHBsAg < 832 IU/ml excluded CHB in 98.4% of cases. A cutoff point for qHBsAg < 100 IU/ml associated with an annual decline of > 0.5 log 10 IU/ml is a good predictor marker of functional cure for hepatitis B. CONCLUSIONS: This study highlights the large short-term fluctuations in HBV DNA in patients with HBeAg-negative chronic HBeAg-negative HBV infection with genotype D. Thus, using the cutoff value of 832 for qHBsAg combined with that of 2,000 for HBV DNA makes it possible to exclude CHB for most patients.

Analysis of borderline oxacillin-resistant Staphylococcus aureus (BORSA) strains isolated in Tunisia.

Twenty-three strains of Staphylococcus aureus with borderline resistance to oxacillin were studied. These strains were not detected by the cefoxitin test, tests for penicillin-binding protein 2a (PBP2a), mecA, and mecA(LGA251) were negative, and the strains were genetically unrelated. To detect all strains resistant to oxacillin, laboratories should routinely test for both cefoxitin and oxacillin.

Chlamydia trachomatis genovar distribution in clinical urogenital specimens from Tunisian patients: high prevalence of C. trachomatis genovar E and mixed infections.

BACKGROUND: This epidemiological study was carried out in Sfax (south of Tunisia) and focused on genital Chlamydia trachomatis (C. trachomatis) genovar distribution. METHODS: One hundred and thirty seven genital samples from 4067 patients (4.2%) attending the Habib Bourguiba University hospital of Sfax over 12 years (from 2000 to 2011) were found to be C. trachomatis PCR positive by the Cobas Amplicor system. These samples were genotyped by an in house reverse hybridization method. RESULTS: One hundred and eight (78.8%) samples contained only one genovar and 29 (21.2%) samples contained two or three genovars. Genovar E was the most prevalent (70.8%) single genovar and it was detected in 90.6% of all the cases. Genovars J, C and L1-L3 were not detected in our samples whereas ocular genovars A and B were in 5 cases. All the five cases were mixed infections. Men had more mixed infections than women (p=0.02) and were more frequently infected by genovars F and K (p<0.05). No associations between current infection, infertility and the genovar distribution were observed. Patients coinfected with Neisseria gonorrhoeae were also significantly more frequently infected with mixed genovars (p=0.04). CONCLUSIONS: In conclusion, we have reported a high prevalence of genovar E and of mixed infections in our study population. Such data could have implications for the control and vaccine development of C. trachomatis in Tunisia.

[The role of neutrophils in the formation of peritoneal adhesions]. / Rôle des polynucléaires neutrophiles dans la formation des adhérences post opératoires.

BACKGROUND: The use of antibiotics during peritonitis appears to decrease the formation of postoperative intra peritoneal adhesions and reduce their severity. The effect of this antibiotic is still controversial. AIM: To study the relationship between the decrease postoperative adhesions induced by rifamycin, and the number of neutrophils and the number of intraperitoneal bacteria. METHODS: This is an experimental prospective, randomized singleblind study performed on adult male rats. The product used for the peritoneal lavage was rifamycin s. The animals were randomized into three groups: Group S: intra peritoneal lavage with saline to 9%, R25 Group: intra peritoneal lavage with rifamycin at a dose of 25 mg / kg group and 12.5 R: intra peritoneal lavage with rifamycin at a dose of 12.5 mg / kg. Adhesions score was evaluated according to Zulkhé by the same operator. RESULTS: The adhesion score was significantly lower between groups S and R12.5 (p = 0.000) and group S and group R25 (P = 0.01). However, the difference was not significant between the two groups R 25 and R12.5 compared to S group (p = 0.655). The number of bacteria between the time of caecal resection (before peritoneal lavage) and the time of death or sacrifice was significantly decreased significantly in the groups R25, comparing the group S (p = 0.003). However, there is no significant difference between groups S and R12, 5 (p = 0.106). The number of neutrophils between the time of cecal resection (before peritoneal lavage) and the time of death or sacrifice decreased significantly in the groups R25 and R12, 5 in comparison to the group S. Between the group R25 and the S group, the difference is significant (p = 0.037) as well between the group R12, 5 and S (p = 0.026). However, there is no significant difference between the two groups R 25 and R12, 5 (p = 0.712). CONCLUSION: The action of rifamycin sodium on neutrophils seems to be independent of its antibacterial action. These findings deserve to be explored at the end to clarify the mechanism of neutropenia by intra peritoneal washing with rifamycin and the relationship between neutropenia and post-operative adhesions.

Relationship Between Serotypes and Antimicrobial Nonsusceptibility of Streptococcus pneumoniae Clinical Isolates in Tunisia.

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.

Antimicrobial resistance genes, virulence markers and prophage sequences in Salmonella enterica serovar Enteritidis isolated in Tunisia using whole genome sequencing.

Salmonella Enteritidis causes a major public health problem in the world. Whole genome sequencing can give us a lot of information not only about the phylogenetic relatedness of these bacteria but also in antimicrobial resistance and virulence gene predictions. In this study, we analyzed the whole genome data of 45 S. Enteritidis isolates recovered in Tunisia from different origins, human, animal, and foodborne samples. Two major lineages (A and B) were detected based on 802 SNPs differences. Among these SNPs, 493 missense SNPs were identified. A total of 349 orthologue genes mutated by one or two missense SNPs were classified in 22 functional groups with the prevalence of carbohydrate transport and metabolism group. A good correlation between genotypic antibiotic resistance profiles and phenotypic analysis were observed. Only resistant isolates carried the respective molecular resistant determinants. The investigation of virulence markers showed the distribution of 11 Salmonella pathogenicity islands (SPI) out of 23 previously described. The SPI-1 and SPI-2 genes encoding type III secretion systems were highly conserved in all isolates except one. In addition, the virulence plasmid genes were present in all isolates except two. We showed the presence of two fimbrial operons sef and ste previously considered to be specific for typhoidal Salmonella. Our collection of S. Enteritidis reveal a diversity among prophage profiles. SNPs analysis showed that missense mutations identified in fimbriae and in SPI-1 and SPI-2 genes were mostly detected in lineage B. In conclusion, WGS is a powerful application to study functional genomic determinants of S. Enteritidis such as antimicrobial resistance genes, virulence markers and prophage sequences. Further studies are needed to predict the impact of the missenses SNPs that can affect the protein functions associated with pathogenicity.