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The Gram-negative bacterial lipopolysaccharide (LPS) is a major component of the outer membrane that plays a key role in host–pathogen interactions with the innate immune system. During infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. Bacterial adaptive changes including modulation of LPS synthesis and structure are a conserved theme in infections, irrespective of the type or bacteria or the site of infection. In general, these changes result in immune system evasion, persisting inflammation and increased antimicrobial resistance. Here, we review the modifications of LPS structure and biosynthetic pathways that occur upon adaptation of model opportunistic pathogens (Pseudomonas aeruginosa, Burkholderia cepacia complex bacteria, Helicobacter pylori and Salmonella enterica) to chronic infection in respiratory and gastrointestinal sites. We also discuss the molecular mechanisms of these variations and their role in the host–pathogen interaction. The authors review modifications of lipopolysaccharide structure and biosynthetic pathways that occur upon bacterial adaptation to chronic respiratory and gastrointestinal infections. Graphical Abstract Figure. The authors review modifications of lipopolysaccharide structure and biosynthetic pathways that occur upon bacterial adaptation to chronic respiratory and gastrointestinal infections.

Abstract Burkitt lymphoma (BL) is an aggressive B-cell non-Hodgkin lymphoma that rarely involves the appendix and may mimic acute appendicitis, complicating preoperative diagnosis. In the context of nonoperative management for appendicitis, such malignancies risk being overlooked. A 32-year-old immunocompetent male presented with right upper quadrant pain, leukocytosis, cholestatic liver profile, and a hepatic lesion on imaging. Positron emission tomography-computed tomography (PET-CT) showed intense fluorodeoxyglucose uptake in the colon, liver, and peritoneum. Laparoscopy revealed an enlarged appendix (15 × 3 cm) with abscess; appendectomy was performed. Histopathology confirmed BL with a ‘starry sky’ pattern and Ki-67 of 95%. Appendiceal BL, though rare, should be suspected in atypical or complicated appendicitis, even without classic risk factors. Histopathological examination of appendectomy specimens is crucial. Surgery, even when not oncologic in intention, may lead to early cancer detection and timely systemic treatment, improving outcomes.

CDC has updated its interim guidance for U.S. health care providers caring for infants with possible congenital Zika virus infection (1) in response to recently published updated guidance for health care providers caring for pregnant women with possible Zika virus exposure (2), unknown sensitivity and specificity of currently available diagnostic tests for congenital Zika virus infection, and recognition of additional clinical findings associated with congenital Zika virus infection. All infants born to mothers with possible Zika virus exposure* during pregnancy should receive a standard evaluation at birth and at each subsequent well-child visit including a comprehensive physical examination, age-appropriate vision screening and developmental monitoring and screening using validated tools (3-5), and newborn hearing screen at birth, preferably using auditory brainstem response (ABR) methodology (6). Specific guidance for laboratory testing and clinical evaluation are provided for three clinical scenarios in the setting of possible maternal Zika virus exposure: 1) infants with clinical findings consistent with congenital Zika syndrome regardless of maternal testing results, 2) infants without clinical findings consistent with congenital Zika syndrome who were born to mothers with laboratory evidence of possible Zika virus infection, and 3) infants without clinical findings consistent with congenital Zika syndrome who were born to mothers without laboratory evidence of possible Zika virus infection. Infants in the first two scenarios should receive further testing and evaluation for Zika virus, whereas for the third group, further testing and clinical evaluation for Zika virus are not recommended. Health care providers should remain alert for abnormal findings (e.g., postnatal-onset microcephaly and eye abnormalities without microcephaly) in infants with possible congenital Zika virus exposure without apparent abnormalities at birth.