Development of an ELISA using a recombinant P46-like lipoprotein for diagnosis of Mycoplasma pulmonis infection in rodents

Rapid Detection of Mycoplasma-Infected Cells by an ssDNA Aptamer Probe

Mycoplasmas are unique cell wall-free bacteria. Because they lack a cell wall and have resistance to β-lactam antibiotics, mycoplasma is the major pathogen that infects cultured cells in research laboratories. For rapid detection of mycoplasma-infected cells, we developed an ssDNA aptamer sequence composed of 40 nucleotides. Flow cytometry analysis showed that the synthetic aptamer probe selectively targeted mycoplasma-infected culture cells with high specificity identical to commercially available PCR-based assays. Additionally, fluorescent microscopy studies revealed that the aptamer probe rapidly stained mycoplasma-infected cells with higher sensitivity compared to Hoechst dye-mediated cellular DNA content stains. Moreover, confocal microscopy studies of trypsin-treated cells validated that the aptamer probes selectively targeted mycoplasma components on the surface of infected cells. Finally, preclinical studies of peripheral blood cells demonstrated that the aptamer probe was able to detect in vitro mycoplasma infection of primary lymphocytes. Taken together, these findings indicate that the aptamer probe will not only allow rapid detection of mycoplasma-infected culture cells for research purposes but also provide a simple method to monitor mycoplasma infection in primary cell products for clinical use.

Bacterial species to be considered in quality assurance of mice and rats

Bacteria are relevant in rodent quality assurance programmes if (a) the animals are at risk and (b) presence in the animals makes a difference for animal research or welfare, for example because the agent regulates clinical disease progression or impacts its host in other ways. Furthermore, zoonoses are relevant. Some bacterial species internationally recommended for the health monitoring of rats and mice, that is, Citrobacter rodentium, Corynebacterium kutscheri, Salmonella spp. and Streptococcus pneumonia, are no longer found in either laboratory or pet shop rats or mice, while there is still a real risk of impact on animal research and welfare from Filobacterium rodentium, Clostridium piliforme, Mycoplasma spp., Helicobacter spp. and Rodentibacter spp., while Streptobacillus moniliformis may be considered a serious zoonotic agent in spite of a very low risk. Modern molecular techniques have revealed that there may, depending on the research type, be equally good reasons for knowing the colony status of some commensal bacteria that are essential for the induction of specific rodent models, such as Alistipes spp., Akkermansia muciniphila, Bifidobacterium spp., Bacteroides fragilis, Bacteroides vulgatus, Faecalibacterium prausnitzii, Prevotella copri and segmented filamentous bacteria. In future, research groups should therefore consider the presence or absence of a short list of defined bacterial species relevant for their models. This list can be tested by cost-effective sequencing or even a simple multiple polymerase chain reaction approach, which is likely to be cost-neutral compared to more traditional screening methods.

Clinical, pathological, and molecular investigation of Mycoplasma pulmonis-induced murine respiratory mycoplasmosis in a rat (Rattus norvegicus) colony

Aim:

Mycoplasma pulmonis (MP) remains potentially important rodent pathogen causing murine respiratory mycoplasmosis (MRM) which may go undiagnosed due to its asymptomatic nature. In the present study, we carried out clinical, pathological, and molecular investigations of MP-induced MRM in a rat colony.

Materials and Methods:

Two female Wistar rats were observed to be diseased in animal facility of NISER, Bhubaneswar, and were kept in isolation for further investigation. Both the animals were found to be positive for MP after serological and molecular tests. Thereafter, whole rat colony comprising of 36 animals was segregated based on clinical symptoms and further sampled for histopathological, serological, and molecular investigations. Tracheal washing and infected lung tissue were collected during necropsy examination for DNA extraction. Molecular diagnosis was done by polymerase chain reaction (PCR) assay using species-specific primers.

Result::

Classical symptoms of MP-associated respiratory tract infection were observed in only 2 of 36 infected animals, and most of the animals were found asymptomatic to the disease; however, all the animals were found to be carrier after necropsy and PCR assay. Gross and histopathological finding suggested severe congestion of the lungs along with suppurative and necrotizing pneumonia. The disease is confirmed by molecular diagnosis using species-specific primers in PCR assay.

Conclusion:

MRM may go undiagnosed due to asymptomatic nature. Detailed study of clinical symptoms, pathology, serology, and PCR-based molecular approach may aid in health monitoring and detection of MRM in a rodent colony reared for experimental purpose.