[Staphylococcus pseudintermedius and Pasteurella dagmatis associated in a case of community-acquired pneumonia]

Severe Pneumonia Caused by Methicillin-Resistant Staphylococcus pseudintermedius in an Oncology Patient: Case Report and Literature Review

Staphylococcus pseudintermedius is usually a commensal bacterium of microbiota of dogs and cats that can become pathogenic in these animals. In the past two decades, an increasing number of human infections caused by this pathogen was reported; only two pediatric cases were due to methicillin-susceptible isolates. We describe the first case of methicillin-resistant S. pseudintermedius diagnosed in a 12-year-old immunocompromised girl with refractory anaplastic ependymoma, presented with life-threatening pneumonia and bacteremia. The girl had close contact with her two pet dogs. This case emphasizes that immunocompromised children should be advised on proper handling of household pets to minimize the risk of infection, which could be life threatening.

Are zoonotic Staphylococcus pseudintermedius strains a growing threat for humans?

Staphylococcus pseudintermedius is a species often isolated from animals, as a common element of their microbiota or an agent of infection, and from people associated with an animal habitat, including owners of home pets—dogs and cats. As with many other species, adaptation of these bacteria to the human body can occur, and they become important human pathogens. 59 S. pseudintermedius strains were investigated in this study to determine the factors contributing to human body colonization: inhibition growth of human skin residents isolated from human skin (Staphylococcus epidermidis, Corynebacterium spp., Cutibacterium acnes (formerly Propionibacterium acnes)), biofilm formation, and the presence of ten genes encoding infection-promoting features (including ebpS, spsE, lukS, lukF, pvl, lip, hlgA, hlgB). The ability of human skin to be colonized and the presence of genes that promote the development of skin infections showed the significant potential of the studied strains in their adaptation to the host. However, while a comparison of the characteristics of animal strains and those isolated from human infections does not allow us to claim that we are the witnesses of the speciation of a new human pathogen, it does indicate their gradual adaptation to the human organism.

Searching for Beta-Haemolysin hlb Gene in Staphylococcus pseudintermedius with Species-Specific Primers

The paper presents an analysis of 51 Staphylococcus pseudintermedius clinically isolated strains from humans and from animals. Staphylococcus pseudintermedius strains’ ability to produce β-haemolysin was evaluated with phenotypic methods (hot–cold effect, reverse CAMP test). In order to determine the hlb gene presence (coding for β-haemolysin) in a genomic DNA, PCR reactions were conducted with two different pairs of primers: one described in the literature for Staphylococcus aureus and recommended for analysing SIG group staphylococci and newly designed one in CLC Main Workbench software. Only reactions with newly designed primers resulted in product amplification, the presence of which was fully compatible with the results of phenotypic β-haemolysin test. Negative results for S. aureus and S. intermedius reference ATCC strains suggest that after further analysis the fragment of hlb gene amplified with primers described in this study might be included in the process of S. pseudintermedius strains identification.

Bacteremia due to Pasteurella dagmatis acquired from a dog bite, with a review of systemic infections and challenges in laboratory identification

Pasteurella dagmatis, a Gram-negative coccobacillus, has been isolated from both dogs and cats as normal flora. It is also a fairly new species for many clinicians because it is a pathogen in human infections. The authors present a case of bacteremia in a 74-year-old man that was caused by P dagmatis. A comparison of other reported cases of bacteremia due to P dagmatis is provided, along with a discussion of the challenges of standard automatic identification including alternative methodologies.

A case of bacteremia in a 74-year-old man, which was caused by Pasteurella dagmatis and complicated by thrombocytopenia, is presented. Microorganism identification was performed by the provincial reference laboratory using traditional biochemical profiling, completmented with both the sequencing of the 16S ribosomal RNA gene and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; antibiotic-susceptibility testing was also performed. After treatment with the appropriate antibiotics, the patient fully recovered. Systemic infections attributed to this organism are rarely reported in the literature. Other reported cases of bacteremia due to P dagmatis are reviewed and compared with the present case. The challenges of relying on standard automatic identification are discussed, with alternative methodologies provided.

Are Staphylococcus intermedius Infections in Humans Cases of Mistaken Identity? A Case Series and Literature Review

Staphylococcus intermedius and Staphylococcus pseudintermedius are difficult to distinguish using conventional microbiological methods. Molecular diagnostic tools change our understanding of the epidemiology of these 2 organisms. In this study, we present (1) a detailed review of the current literature on molecular diagnostics and (2) a case series in which misidentification was proven in 1 case. We conclude that S pseudintermedius is a more common human pathogen than previously recognized.