Chlamydiaceae: Diseases in Primary Hosts and Zoonosis

Abstract

Bacteria of the Chlamydiaceae family are a type of Gram-negative microorganism typified by their obligate intracellular lifestyle. The majority of the members in the Chlamydiaceae family are known pathogenic organisms that primarily infect the host mucosal surfaces in both humans and animals. For instance, Chlamydia trachomatis is a well-known etiological agent for ocular and genital sexually transmitted diseases, while C. pneumoniae has been implicated in community-acquired pneumonia in humans. Other chlamydial species such as C. abortus, C. caviae, C. felis, C. muridarum, C. pecorum, and C. psittaci are important pathogens that are associated with high morbidities in animals. Importantly, some of these animal pathogens have been recognized as zoonotic agents that pose a significant infectious threat to human health through cross-over transmission. The current review provides a succinct recapitulation of the characteristics as well as transmission for the previously established members of the Chlamydiaceae family and a number of other recently described chlamydial organisms.

Optimal cultivation of Chlamydia requires testing of serum on individual species

“…Ct and Cm are known to infect only human and mouse, respectively. However, multiple other Chlamydia species, namely C. pecorum and C. abortus, C. pneumoniae, C. psittaci and C. gallinacean are known to infect cows [9,16]. Thus, it should not be surprising if FBS or NBCS contains anti-chlamydia antibodies because maternal IgG is capable of entering the fetal blood stream.…”

“…Whereas C. trachomatis is the number one sexually transmitted pathogenic bacterium [7], C. pneumoniae causes communicable respiratory infections [8]. Other Chlamydia species known as pathogens of animals including livestock may cause severe illness in humans after their contact with infected animals [9]. C. psittaci, cause of psittacosis, is the best example of zoonotic Chlamydia.…”

Chlamydiae from Down Under: The Curious Cases of Chlamydial Infections in Australia

“…Detection of Cps in grazing livestock (cattle, sheep, horses and pigs) is common globally, and it is estimated that Cps infection/detection rates can be as high as 50% in a herd while the pathogen itself causes a range of diseases (such as ocular infections, pneumonia, vaginitis and mastitis) [1,78,87]. In contrast, until recently the reports in Australia were anecdotal, inconclusive and rare.…”

“…The diverse members of the phylum Chlamydiae constantly remain in the global spotlight, attracting attention not just as successful and enigmatic human and animal pathogens [1], but also by cutting-edge biological and "omics" research involving Chlamydiae [2,3]. From a global public perspective, Chlamydiae in Australia are perhaps best known as the notorious pathogens of the iconic marsupial, koala (Phascolarctos cinereus).…”

Chlamydia abortus in Pregnant Woman with Acute Respiratory Distress Syndrome

“…The infection in pregnant women often requires hospitalization in an intensive care unit and causes fetal death (5). Most reported cases of human infection involve direct contact of pregnant women with infected animals, but indirect contact by visiting or living on or close to a farm affected by enzootic abortion also has been described (6). When pregnant women, especially those who live in rural areas, arrive in the emergency department with rapidly worsening influenza-like illness, a thorough patient history is necessary, and clinicians should give special attention to possible contact with animals from an infected herd (5).…”