Staphylococcus pseudintermedius

Abstract: Abstract Background: Staphylococcus spp., and Pseudomonas spp., including multidrug resistant staphylococci are frequent isolates from canine otitis externa and atopic dermatitis. Biofilm formation by these organisms may be important in otitis chronicity. With ear cleanser products commonly used to control microbial overgrowth, it is important to measure their antibiofilm effects. Six ear cleansers (EpioticⓇ SIS, EpioticⓇ Advanced, CleanauralⓇ, Otifree, PeptivetⓇ and SonotixⓇ) were evaluated against infection isolates of Pseudomonas aeruginosa , methicillin resistant and sensitive Staphylococcus aureus and Staphylococcus pseudintermedius . Antibiofilm activity was measured colorimetrically via the presence of viable cells as detected by the reduction of a thiazolyl blue tetrazolium bromide compound (MTT). Minimum inhibitory concentration (MIC) of EpioticⓇ SIS and EpioticⓇ Advanced were measured using a broth micro-dilution assay to ascertain inhibition in planktonic phase. Results: EpioticⓇ (SIS and Advanced), CleanauralⓇ and PeptivetⓇ showed strong antibiofilm activity, with Otifree and SonotixⓇ showing moderate to low antibiofilm activity. Differences in inhibition between the methicillin resistant and sensitive staphylococcal isolates were also observed between the products with Otifree showing significantly less inhibition of the resistant isolate of S. aureus compared to the sensitive isolate. P. aeruginosa biofilms were less effectively disrupted by some ear cleansers compared to EpioticⓇ, and the MIC results indicated that less diluted solutions were required to inhibit this isolate compared to the staphylococci. Differences in the antibacterial effects between EpioticⓇ SIS and EpioticⓇ Advanced solutions could also be detected from the MIC assays suggesting differences in formulations can affect antimicrobial efficacy. Conclusions: Commonly used canine ear cleanser products showed activity against multidrug resistant and sensitive Staphylococcus spp. and P. aeruginosa isolates in both biofilm and planktonic phases. Differences between strains and cleansers were observed that should enable better targeted use of these products.

Abstract: The objective of this study was to compare virulence and resistance factors of mucosal and cutaneous staphylococci from dogs with pyoderma in the UK and Romania, two countries with different approaches to antimicrobial use in companion animals. Staphylococcal isolates (n = 166) identified to the species level as being Staphylococcus pseudintermedius or coagulase negative (CoNS) were analyzed for their antimicrobial resistance (AMR) profile and presence of resistance and virulence genes. Of the investigated isolates, 26 were methicillin-resistant S. pseudintermedius (MRSP), 89 were methicillin-susceptible S. pseudintermedius (MSSP) and 51 were coagulase negative staphylococci (CoNS). A significantly larger number of isolates originating from Romania were resistant to clindamycin, tetracycline, and chloramphenicol compared to the UK isolates (P < 0.05). Resistance to amoxicillin-clavulanic acid, gentamicin, and trimethoprim-sulphamethoxazole was more evident in UK isolates. Fusidic acid resistance was common in Staphylococcus spp. isolates from both countries. Most isolates carried virulence factors associated with siet (exfoliative toxin) and luk (leucocidin) genes. All MRSP UK isolates exhibited fusidic acid resistance genes whilst this was very rare in the MRSP isolates from Romania. The chlorhexidine resistance gene qacA/B was frequently identified in CoNS isolates from the UK (P < 0.001). The current study documented differences in antimicrobial resistance profiles of Staphylococcus spp. isolates from dogs in two geographical locations in Europe, which could reflect differences in antimicrobial prescribing patterns. The study also highlights the need for further studies and interventions on antimicrobial use, prescribing patterns and AMR surveillance in companion animals in Romania.

Abstract: Staphylococcus pseudintermedius is an important pathogen in dogs that occasionally causes infections in humans as an opportunistic pathogen of elderly and immunocompromised people. This study compared the genomic relatedness and antimicrobial resistance genes using genome-wide association study (GWAS) to examine host association of canine and human S. pseudintermedius isolates. Canine (n = 25) and human (n = 32) methicillin-susceptible S. pseudintermedius (MSSP) isolates showed a high level of genetic diversity with an overrepresentation of clonal complex CC241 in human isolates. This clonal complex was associated with carriage of a plasmid containing a bacteriocin with cytotoxic properties, a CRISPR-cas domain and a pRE25-like mobile element containing five antimicrobial resistance genes. Multi-drug resistance (MDR) was predicted in 13 (41%) of human isolates and 14 (56%) of canine isolates. CC241 represented 54% of predicted MDR isolates from humans and 21% of predicted MDR canine isolates. While it had previously been suggested that certain host-specific genes were present the current GWAS analysis did not identify any genes that were significantly associated with human or canine isolates. In conclusion, this is the first genomic study showing that MSSP is genetically diverse in both hosts and that multidrug resistance is important in dog and human-associated S. pseudintermedius isolates.

Abstract: Staphylococcus pseudintermedius commonly colonizes companion animals, including canines. This microbe is a major opportunistic pathogen responsible for pyogenic and necrotizing skin and soft tissue infection in canines. Infection with S. pseudintermedius is increasingly being recognized in humans, especially in those who are immunocompromised. This microbe is quite similar to Staphylococcus aureus, expressing several analogous virulence factors and a variety of toxins. Furthermore, S. pseudintermedius has variants that display multi-drug resistance comparable to methicillin-resistant S. aureus. We report a 50-year-old female with bilateral lung transplant on immunosuppression who presents with signs of sepsis and pneumonia. Initial blood cultures grew Gram-positive cocci that were not initially identified via molecular diagnostics as Staphylococcus species but were later confirmed as S. pseudintermedius through mass spectrometry. Antimicrobial susceptibility testing demonstrated multi-drug resistance, including methicillin. Despite aggressive medical and antimicrobial treatment, our patients succumbed to the infection. The source of infection likely came from her companion canine at home as no other source could be identified; however, cultures were unable to be obtained from the companion canine. Those who are immunosuppressed, such as with solid organ transplants, should take caution with exposure to companion animals due to the potential for S. pseudintermedius infection.