Implementation of a prospective study for enhancing surveillance of invasive bacterial infections in North Africa.

OBJECTIVES: We implemented a project named MENINGSTOP in three countries of North Africa (Algeria, Morocco and Tunisia). The main objective was to use real-time PCR to detect, identify and type the three main agents (Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae) responsible for invasive bacterial infections (IBI). METHODS: The protocol of WHO and US CDC for real-time PCR was used to detect and type the three bacterial agents in clinical samples. We also designated two quality exercises using an external interlaboratory study and cross-testing of 10% of randomly selected samples. RESULTS: Among the 752 samples tested, 18% were positive for one of the three agents. N. meningitidis was the most frequent globally reaching 9% of all samples (7% to 17% range) followed by S. pneumoniae 8% of all samples (6% to 15%). Group B meningococci was the most frequent (74% of all positive samples for meningococci and ranging from 50% to 90%). Quality assurance showed >85% correlation scores. CONCLUSIONS: Real-time PCR can help improving epidemiological surveillance. Data confirm the prevalence of meningococci B. Our project adds a reliable tool to enhance surveillance and to help decision making in vaccination strategies against IBI.

Severe and critical SARS-COV-2 delta variant infection in infants without underlying medical conditions.

We report herein a case series of infants, with no comorbidities, who developed a life-threatening illness due to the SARS-CoV-2 Delta variant. We retrospectively reviewed the medical records of children, aged under 15 years, admitted to PICU, during the peak of Delta infection, between June 23 and August 16 2021, with severe and critical forms of SARS-CoV-2 infection, confirmed by RT-PCR. Twenty infants were included, the median age was 47 days (IQR: 26.5-77) and sex ratio was 0.8. No underlying medical conditions were noted. Parents were not vaccinated. Respiratory involvement was the main feature observed. Eleven patients had paediatric acute respiratory distress (PARDS) with a median oxygen saturation index (OSI) of 9 (IQR: 7-11). PARDS was mild in four, moderate in five, and severe in two cases. Hemodynamic instability was observed in 4 cases. The main radiological finding was ground glass opacities in 11 cases. Seventeen patients were mechanically ventilated, and three of them were escalated to high-frequency oscillatory ventilation. The median duration of mechanical ventilation was 6 days (IQR 2.5-12.5). The remaining patients were managed with high-flow nasal cannula. Four patients died.

High genotypic diversity of Rhinoviruses obtained from Tunisian children with severe acute respiratory infection.

INTRODUCTION: Rhinoviruses (HRV) are among the leading causes of Severe Acute Respiratory Infection (SARI). Their burden and genetic diversity vary from one region to another and little is known in Northern African regions. This study describes epidemiological patterns and genotypic diversity of HRV in SARI cases during a two and half year's study, in Northern Tunisia. METHODOLOGY: A total of 271 SARI cases, admitted into the Pediatric Intensive Care Unit of Bechir Hamza Children's Hospital in Tunis, were collected between September 2015 and December 2017. The investigation concerned 104 samples positive for HRV and/or HEV (Human Enterovirus) obtained among these cases. Specific HRV and HEV detections were assessed by real-time PCRs. The HRV molecular typing was based on the VP4-VP2 genomic region analyses. RESULTS: Among the viral SARI cases, 33.5% and 12.3% were positive for HRV and HEV respectively. Molecular investigations showed high prevalence of HRV-A (63.3%) followed by HRV-C (30.6%) and HRV-B (6.1%) and high genotypic diversity with 27 types. HRV cases were mostly detected in toddlers younger than 6 months. A total of 16 cases (28%) were found with bacterial and/or viral co-infection. HRV-C infection and HRV-A with bacterial co-infection were associated with complicated infection. Some of the detected types showed a continuous circulation or turnover during an extended period. HRV-A101 and HRV-C45 were the most frequently detected types. CONCLUSIONS: This study revealed, for the first time, the high HRV diversity in Tunisia, a North-African region. Specific phylogenetic investigations may help to evaluate their diversity and to trace their spread and epidemiological origin.

Phylogeography and phylogeny of Rhinoviruses collected from Severe Acute Respiratory Infection (SARI) cases over successive epidemic periods in Tunisia.

Rhinoviruses (RV) are a major cause of Severe Acute Respiratory Infection (SARI) in children, with high genotypic diversity in different regions. However, RV type diversity remains unknown in several regions of the world. In this study, the genetic variability of the frequently circulating RV types in Northern Tunisia was investigated, using phylogenetic and phylogeographic analyses with a specific focus on the most frequent RV types: RV-A101 and RV-C45. This study concerned 13 RV types frequently circulating in Northern Tunisia. They were obtained from respiratory samples collected in 271 pediatric SARI cases, between September 2015 and November 2017. A total of 37 RV VP4-VP2 sequences, selected among a total of 49 generated sequences, was compared to 359 sequences from different regions of the world. Evolutionary analysis of RV-A101 and RV-C45 showed high genetic relationship between different Tunisian strains and Malaysian strains. RV-A101 and C45 progenitor viruses' dates were estimated in 1981 and 1995, respectively. Since the early 2000s, the two types had a wide spread throughout the world. Phylogenetic analyses of other frequently circulating strains showed significant homology of Tunisian strains from the same epidemic period, in contrast with earlier strains. The genetic relatedness of RV-A101 and RV-C45 might result from an introduction of viruses from different clades followed by local dissemination rather than a local persistence of an endemic clades along seasons. International traffic may play a key role in the spread of RV-A101, RV-C45, and other RVs.