Polyomavirus (PyV) infections were first described in mice in 1952 as a cause of tumors in newborn animals. Since then, PyVs have been found in virtually all vertebrates, including primates, monkeys, cows, rabbits, birds, and fish. BK polyomavirus (BKPyV) was…
Adenoviruses In the past few decades, significant progress has been made in understanding the epidemiology of adenovirus infections and developing preventative and therapeutic strategies. However, adenovirus infections remain a clinical and diagnostic challenge. Isolation of adenovirus does not necessarily correlate…
Epidemiology and risk factors The seasonality of respiratory virus infections among immunocompromised children is similar to that in the community ( Fig. 21.1 ). Respiratory syncytial virus (RSV) typically circulates in the community from November through March, with peak detection…
Over the past several decades, three novel human herpesviruses (HHVs) have been identified and designated HHV-6, HHV-7, and HHV-8. HHV-6 has since been designated as two distinct species, HHV-6A and HHV-6B. HHV-6 was first isolated from the white blood cells…
Herpes simplex virus (HSV) types 1 and 2 (HSV-1 and -2) and varicella-zoster virus (VZV) comprise the human α-herpesviruses, a subfamily of enveloped, double-stranded DNA viruses defined in part by the ability to be transmitted and replicate in mucoepithelial surfaces…
Epstein-Barr virus (EBV) is a human γ-herpesvirus that is associated with important syndromes in both the immunocompetent and immunocompromised host. It is a ubiquitous virus, as it is found worldwide. In community settings, EBV is primarily transmitted by exposure to…
Viral infections represent a significant cause of morbidity and mortality among children who have undergone either solid organ (SOT) or hematopoietic stem cell transplantation (HSCT), as well as in children undergoing therapy for malignancies. Herpesviruses, which possess a unique ability…
Mycobacterium tuberculosis infection Epidemiology, risk factors, and pathogenesis Mycobacterium tuberculosis ( MTB) is among the most successful respiratory pathogens worldwide as the majority of those infected are asymptomatic and will live their lifetime without clinical manifestations. Latent infection is defined…
Bartonella Epidemiology and risk factors Bartonella species are fastidious, slow-growing, gram-negative bacilli. There are 45 different species that can cause disease in zoonotic hosts, with Bartonella henselae and Bartonella quintana causing most Bartonella -related disease in human hosts in the…
Common mechanisms of gram-negative resistance Gram-negative organisms are divided into the Enterobacteriaceae (e.g., Escherichia coli, Klebsiella species, Enterobacter cloacae ) and the glucose nonfermenting gram-negative organisms ( Pseudomonas aeruginosa , Acinetobacter baumannii , Stenotrophomonas maltophilia ). Drug resistance in Enterobacteriaceae…