Evolutionary Conservation of Infection-Induced Cell Death Inhibition among Chlamydiales

Control of host cell death is of paramount importance for the survival and replication of obligate intracellular bacteria. Among these, human pathogenic Chlamydia induces the inhibition of apoptosis in a variety of different host cells by directly interfering with cell death signaling. However, the evolutionary conservation of cell death regulation has not been investigated in the order Chlamydiales, which also includes Chlamydia-like organisms with a broader host spectrum. Here, we investigated the apoptotic response of human cells infected with the Chlamydia-like organism Simkania negevensis (Sn). Simkania infected cells exhibited strong resistance to apoptosis induced by intrinsic stress or by the activation of cell death receptors. Apoptotic signaling was blocked upstream of mitochondria since Bax translocation, Bax and Bak oligomerisation and cytochrome c release were absent in these cells. Infected cells turned on pro-survival pathways like cellular Inhibitor of Apoptosis Protein 2 (cIAP-2) and the Akt/PI3K pathway. Blocking any of these inhibitory pathways sensitized infected host cell towards apoptosis induction, demonstrating their role in infection-induced apoptosis resistance. Our data support the hypothesis of evolutionary conserved signaling pathways to apoptosis resistance as common denominators in the order Chlamydiales

Fatores associados às complicações em crianças pré-escolares com pneumonia adquirida na comunidade Factors associated with complications of community-acquired pneumonia in preschool children

OBJETIVO: Identificar os fatores socioeconômicos e clínicos associados à evolução para complicações em crianças internadas com pneumonia adquirida na comunidade (PAC). MÉTODOS: Estudo longitudinal prospectivo em crianças diagnosticadas com PAC (12-59 meses de idade) internadas em enfermarias gerais de pediatria de dois hospitais na região de Campinas (SP). Os critérios de exclusão foram ter fibrose cística, cardiopatia, malformação pulmonar, neuropatias e doenças genéticas. PAC foi diagnosticada por características clínicas e radiológicas. Os dados foram coletados dos prontuários médicos e por um questionário semiestruturado. Os sujeitos foram divididos em dois grupos (PAC complicada e não complicada). Foram comparadas variáveis socioeconômicas e clínicas, e foi realizada análise de regressão logística multivariada. RESULTADOS: Das 63 crianças incluídas, 29 e 34, respectivamente, apresentaram PAC não complicada e PAC complicada. Não houve diferenças estatisticamente significantes entre os grupos quanto a idade na admissão, idade gestacional, peso ao nascer, gênero ou variáveis socioeconômicas. Houve diferenças significantes entre os grupos em relação a pneumonia anterior (p = 0,03), antibioticoterapia prévia (p = 0,004), tempo de início da doença (p = 0,01), duração da febre antes da internação (p < 0,001), duração da antibioticoterapia (p < 0,001) e tempo de internação (p < 0,001). Na análise multivariada, somente permaneceu no modelo a duração da febre antes da internação (OR = 1,97; IC95%: 1,36-2,84; p < 0,001). CONCLUSÕES: Variáveis biológicas, com destaque para o tempo de febre anterior à internação, parecem estar associadas com a evolução para complicação em crianças com PAC.<br>OBJECTIVE: To identify socioeconomic factors and clinical factors associated with the development of complications in preschool children hospitalized with community-acquired pneumonia (CAP). METHODS: This was a prospective longitudinal study involving children (12-59 months of age) diagnosed with CAP and admitted to the pediatric wards of two hospitals in the metropolitan area of Campinas, Brazil. Children with cystic fibrosis, heart disease, pulmonary malformations, neurological disorders, or genetic diseases were excluded. The diagnosis of CAP was based on clinical and radiological findings. Data were collected from the medical records and with a semi-structured questionnaire. The subjects were divided into two groups (complicated and uncomplicated CAP). Socioeconomic and clinical variables were compared, and multivariate logistic regression analysis was performed. RESULTS: Of the 63 children included, 29 and 34, respectively, presented with uncomplicated and complicated CAP. No statistically significant differences were found between the groups regarding age at admission, gestational age, birth weight, gender, or socioeconomic variables. Significant differences were found between the groups regarding history of pneumonia (p = 0.03), previous antibiotic therapy (p = 0.004), time elapsed since the onset of CAP (p = 0.01), duration of fever prior to admission (p < 0.001), duration of antibiotic therapy (p < 0.001), and length of hospital stay (p < 0.001). In the multivariate analysis, only duration of fever prior to admission remained in the model (OR = 1.97; 95% CI: 1.36-2.84; p < 0.001). CONCLUSIONS: Biological variables, especially duration of fever prior to admission, appear to be associated with the development of complications in children with CAP

Deconstructing the Chlamydial Cell Wall

The evolutionary separated Gram-negative Chlamydiales show a biphasic life cycle and replicate exclusively within eukaryotic host cells. Members of the genus Chlamydia are responsible for many acute and chronic diseases in humans, and Chlamydia-related bacteria are emerging pathogens. We revisit past efforts to detect cell wall material in Chlamydia and Chlamydia-related bacteria in the context of recent breakthroughs in elucidating the underlying cellular and molecular mechanisms of the chlamydial cell wall biosynthesis. In this review, we also discuss the role of cell wall biosynthesis in chlamydial FtsZ-independent cell division and immune modulation. In the past, penicillin susceptibility of an invisible wall was referred to as the "chlamydial anomaly." In light of new mechanistic insights, chlamydiae may now emerge as model systems to understand how a minimal and modified cell wall biosynthetic machine supports bacterial cell division and how cell wall-targeting beta-lactam antibiotics can also act bacteriostatically rather than bactericidal. On the heels of these discussions, we also delve into the effects of other cell wall antibiotics in individual chlamydial lineages