Clinical and molecular features of methicillin-resistant, coagulase-negative staphylococci of pets and horses.

The research article describes the study performed to analyze antibiotic resistance and genetic profiles of a group of bacteria called methicillin-resistant coagulase-negative staphylococci (MRCoNS) found in pet and horse infections. The scientists also examined the history of antibiotic treatments for these infections.

Research Methodology

• Isolates of MRCoNS from infected animals were identified using a technique called mass spectrometry.
• Their resistance to different antimicrobial drugs was tested using broth dilution, microarrays, and sequence analysis of the topoisomerases, enzymes involved in DNA replication.
• The diversity of the isolates was assessed using methods such as PFGE (pulsed-field gel electrophoresis), checking for the presence of the icaA gene through PCR (polymerase chain reaction), determining the type of staphylococcal cassette chromosome mec (SCCmec), arginine catabolic mobile element (ACME), and performing multilocus sequence typing.
• Clinical records of the infected animals were also examined retrospectively to understand the history of antibiotic treatments.

Results of the Study

• Various strains of MRCoNS were identified in the infections, including Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus capitis, Staphylococcus cohnii, and Staphylococcus warneri.
• Genetic diversity was present in these strains, with different lineages detected in various strains. S. epidermidis was found to have 14 unique sequence types, with ST2 and ST5 being the most common.
• Some strains contained SCCmec IV and SCCmec V genetic elements, while others could not be typed. ACMEs were detected in 11 S. epidermidis isolates, while 10 S. epidermidis and 1 S. hominis were found to be positive for the icaA gene.
• Along with resistance to β-lactam antibiotics due to the mecA gene, resistance was also found to other antibiotics such as gentamicin/kanamycin, macrolides/lincosamides, tetracycline, streptomycin, trimethoprim, sulfamethoxazole, and fluoroquinolones.
• The clinical data suggested that these resistance patterns were selected through multiple courses of antibiotics, highlighting the need for accurate diagnosis and proper selection of antibacterial drugs.

Conclusions

• MRCoNS from animal infection sites are genetically diverse and exhibit resistance to multiple drugs. This poses a challenge in the prevention and treatment of these bacterial infections in veterinary clinics.