An overview of human infections caused by &lt;em&gt;Staphylococcus pseudintermedius:&lt;/em&gt; A zoonotic risk of the oldest friend

MAR Priyantha

doi:10.4038/sljid.v12i1.8415

Abstract

Staphylococcus pseudintermedius is colonized in 90% of healthy dogs and the infection has also been reported in humans who have close contact with dogs. S. pseudintermedius is a Gram positive coagulase positive coccus which is an opportunistic pathogen. Human infection has been reported less frequently either due to misidentification or misdiagnosis or to underreporting. The objective of this overview is to highlight the epidemiology, clinical presentation, importance of laboratory tests and antimicrobial resistance of S. pseudintermedius in humans.Human infections of S. pseudintermedius have been reported as case studies or clusters of infections in the literature. Several cases have been reported among the adult population, and in patients with metabolic diseases such as diabetes mellitus, immunocompromised states such as AIDS, cancers, and autoimmune diseases. The organism had been isolated and identified both in healthy people and individuals with adverse clinical outcomes. S. pseudintermedius causes skin and soft tissue infections, catheter associated infections and surgical site infections in humans. The incidence of skin and soft tissue infection by S. pseudintermedius in humans was 0.025% in Canada. Methicillin resistance S. pseudintermedius (MRSP) has been isolated both in healthy people and associated with clinical infections. MRSP is often multidrug resistant and therapeutic options are limited. Multidrug resistance has been detected in methicillin susceptible S. pseudintermedius (MSSP). Close association of a canine host is the major risk factor in humans and vulnerable individuals need to be persuaded to practice hygienic practices to minimize the risk of zoonotic infection.In conclusion, differentiation of S. pseudintermedius from S. aureus is required to understand the epidemiology of the disease, diagnosis, clinical presentation, and further interpretation of antimicrobial resistance in the human clinical context. Suitable hygienic practices post handling of dogs and improvement of laboratory facilities would help minimize the incidence of S. pseudintermedius infections in humans.

Highlights

The nomenclature of S. pseudintermedius is quite complicated, S. pseudintermedius, S. intermedius and S. delphini are collectively called S. intermedius group.[1]
Since S. aureus is the dominant pathogen in humans and both S. aureus and S. pseudintermedius are coagulase positive, laboratory misidentification is a possible reason for the low number of reports.[6]
S. pseudintermedius is a Gram positive coccus which is readily grown on 5% sheep blood agar.[1,17]

Summary

Introduction

The nomenclature of S. pseudintermedius is quite complicated, S. pseudintermedius, S. intermedius and S. delphini are collectively called S. intermedius group.[1] S. pseudintermedius is a coagulase positive Gram positive coccus which colonizes 90% of healthy dogs.[2] It is an opportunistic pathogen, and the most common cause of canine pyoderma, otitis externa and the second commonest cause of urinary tract infection in dogs.[3] Zoonotic infections have been reported worldwide with a range of clinical presentations.[4] reporting of this organism from human samples is rare.[5] The organism is often misidentified as S. aureus due to cultural, morphological and biochemical similarity.[6,7,8] Importantly, since S. aureus is the dominant pathogen in humans and both S. aureus and S. pseudintermedius are coagulase positive, laboratory misidentification is a possible reason for the low number of reports.[6] Differentiation of S. pseudintermedius from S. aureus is required for further identification. S. pseudintermedius was isolated and identified in complicated urinary tract infections in senior citizens.[33]

D Mannitol

Findings

Conclusion