Mendelian Susceptibility to Mycobacterial Disease Caused by a Novel Founder IL12B Mutation in Saudi Arabia.

PURPOSE: Mendelian susceptibility to mycobacterial disease (MSMD) is a rare primary immunodeficiency predisposing congenitally affected individuals to diseases caused by weakly virulent mycobacteria, such as Bacillus Calmette-Guérin (BCG) vaccine strains and environmental mycobacteria. IL-12p40 deficiency is a genetic etiology of MSMD resulting in impaired IL-12- and IL-23-dependent IFN-γ immunity. Most of the reported patients with IL-12p40 deficiency originate from Saudi Arabia (30 of 52) and carry the recurrent IL12B mutation c.315insA (27 of 30). METHODS: Whole-exome sequencing was performed on three patients from two unrelated kindreds from Saudi Arabia with disseminated disease caused by a BCG vaccine substrain. RESULTS: Genetic analysis revealed a homozygous mutation, p.W60X, in exon 3 of the IL12B gene, resulting in complete IL12p40 deficiency. This mutation is recurrent due to a new founder effect. CONCLUSIONS: This report provides evidence for a second founder effect for recurrent mutations of IL12B in Saudi Arabia.

Group B streptococcal endocarditis.

Group B Streptococcus can cause early onset neonatal disease. Beyond neonatal life, group B Streptococci are unusual pathogens. It can cause septicemia, epiglottis, fascitis, and endocarditis. A male Saudi child with group B endocarditis who has congenital heart disease is discussed.

Streptococcus pneumoniae resistance to penicillin and ceftriaxone in a tertiary care center in Saudi Arabia.

OBJECTIVE: The proportion of penicillin and ceftriaxone resistant Streptococcus pneumoniae isolates and associated risk factors varies by geographic areas in the world. We conducted a retrospective study to determine the extent of penicillin and ceftriaxone non-susceptible Streptococcus pneumoniae bacteremia in a tertiary care medical center in the city of Riyadh, Kingdom of Saudi Arabia. METHODS: We reviewed 172 episodes of Streptrococcus pneumoniae bacteremic diseases involving 160 hospitalized patients at King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia, over a 5 year period between January 1995 through to December 1999. Patients' characteristics and underlying illnesses of those patients with bacteremias and meningitis caused by Streptococccus pneumoniae as well as antimicrobial susceptibility were examined. RESULTS: The majority of patients affected with Streptococcus pneumoniae bacteremia were children <5 years of age (number=91, 53%). Malignant diseases were the main underlying diagnosis in our patient population affected with pneumoncoccal bacteremia (number=46, 27%). Overall (51%) of the isolates were penicillin non-susceptible; of these (7%) were highly resistant. The overall resistance rate to ceftriaxone was 7%. CONCLUSION: With the high prevalence in Streptococcus pneumoniae antimicrobial resistance to penicillin and ceftriaxone, it is important to continue surveillance of infections caused by Streptococcus pneumoniae, and also we recommend that guidelines for treatment and prevention of pneumococcal infection must be addressed by health care and public health agencies.