Class 1 integrons in Acinetobacter baumannii: a weak expression of gene cassettes to counterbalance the lack of LexA-driven integrase repression.

Integrons recruit resistance genes through integrase-driven recombination events that are regulated by the bacterial SOS response and require the repressor LexA. Class 1 integrons genes are expressed from a common promoter, Pc, of which at least 5 predominant variants, classified from weak to strong, have been described. In Escherichia coli, there is an intertwined regulation between gene cassette expression and integrase activity: the stronger the promoter, the weaker the integrase. Class 1 integrons have been frequently described in Acinetobacter baumannii. However, Acinetobacter spp. lack the LexA repressor, suggesting that the integrase is constitutively expressed. We characterized the integron content of 83 clinical and environmental A. baumannii strains. We found a predominance of Pc variants described as strong in E. coli. The Pc expression level was 2- to 4-fold lower in A. baumannii than in E. coli, and the diversity of the gene cassette array was low. In A. baumannii, integrons with a PcS promoter might have been selected to enable sufficient resistance while avoiding the toxicity of a highly active integrase. Furthermore, a transcriptional interference between PcS and PintI1 (as shown in E. coli) may limit the expression of the integrase and thus counterbalance the lack of LexA-driven integrase repression to prevent the cost of the integrase.

Maternal malaria but not schistosomiasis is associated with a higher risk of febrile infection in infant during the first 3 months of life: A mother-child cohort in Benin.

BACKGROUND: Malaria and schistosomiasis represent two of the most prevalent and disabling parasitic infections in developing countries. Few studies have evaluated the effect of maternal schistosomiasis and malaria in the peri-conceptional period on infant's risk of infection. METHODS: In Benin, women were followed from the preconception period until delivery. Subsequently, their children were followed from birth to 3 months of age. Pre-pregnancy malaria, malaria in pregnancy (MiP)-determined monthly using a thick blood smear-and urinary schistosomiasis-determined once before pregnancy and once at delivery using urine filtration-were the main maternal exposures. Infant's febrile infection (fever with respiratory, gastrointestinal and/or cutaneous clinical signs anytime during follow-up) was the main outcome. In a secondary analysis, we checked the relation of malaria and schistosomiasis with infant's hemoglobin (Hb) concentration. Both effects were separately assessed using logistic/mixed linear regression models. RESULTS: The prevalence of MiP was 35.7% with 10.8% occurring during the 1st trimester, and the prevalence of schistosomiasis was 21.8%. From birth to 3 months, 25.3% of infants had at least one episode of febrile infection. In multivariate analysis, MiP, particularly malaria in the 1st trimester, was significantly associated with a higher risk of infant's febrile infection (aOR = 4.99 [1.1; 22.6], p = 0.03). In secondary results, pre-pregnancy malaria and schistosomiasis were significantly associated with a lower infant's Hb concentration during the first 3 months. CONCLUSION: We evidenced the deleterious effect of maternal parasitic infections on infant's health. Our results argue in favor of the implementation of preventive strategies as early as in the peri-conception.

Fungal diagnostics: review of commercially available methods.

Fungi and yeasts are critical causes of acute infection. As such, the detection and identification of these organisms are crucial in the diagnosis of affected patient populations. There is a vast array of commercial tests currently available for diagnostic purposes. These vary from traditional culture and biochemical methods to advanced multiparameter molecular tests. Recent technological advances have driven the development of rapid tests which are complementing and in some cases replacing the more traditional methods of detection. Irrespective of the method used the ultimate goal is timely detection of the infectious agent allowing appropriate treatment and improved outcome for the patient.