JC and BK polyomaviruses were discovered over 40 years ago and have become increasingly prevalent causes of morbidity and mortality in a variety of distinct, immunocompromised patient cohorts. The recent discoveries of eight new members of the Polyomaviridae family that are capable of infecting humans suggest that there are more to be discovered and raise the possibility that they may play a mo...

The genus Bartonella includes important human-specific and zoonotic pathogens which cause intraerythrocytic bacteremia in their mammalian reservoir host(s). It is accepted that cellular immunity plays a decisive role in the host's defense against most intracellular bacteria. Bartonella sp. infection in the immunocompetent host typically leads to immunity against homologous challenge. The basis ...

an immunosuppressed man was admitted to hospital with diarrhea and a history of urinary tract infection. he was subjected to treatment with antibiotics. the patient died of putative severe sepsis. the etiological agent was a carbapenemase producing isolate of bacillus circulans with resistance to all prescribed antimicrobial agents.

A2. This is a very interesting question. In antimicrobial research, the ability of an antibiotic to produce a three-log kill (decrease the bacterial load by three logs) is an important characteristic. In theory, if an antibiotic is able to produce a threelog kill, the host’s immune system can usually kill the remaining bacterial population. However, with an immunocompromised host, such as an HI...

The spectrum of infectious diseases has shifted in the past 50 years to include those caused by microbes that cause disease predominantly in immunocompromised individuals. This phenomenon has underscored the dependence of microbial virulence on the immune status of the host. The limited efficacy of the available antimicrobial armamentarium in immunocompromised individuals, combined with increas...