Staphylococcus ratti sp. nov. Isolated from a Lab Rat

Staphylococci from the Staphylococcus intermedius-Staphylococcus hyicus species group include numerous animal pathogens and are an important reservoir of virulence and antimicrobial resistance determinants. Due to their pathogenic potential, they are possible causative agents of zoonoses in humans; therefore, it is important to address the properties of these strains. Here we used a polyphasic taxonomic approach to characterize the coagulase-negative staphylococcal strain NRL/St 03/464T, isolated from the nostrils of a healthy laboratory rat during a microbiological screening of laboratory animals. The 16S rRNA sequence, MALDI-TOF mass spectrometry and positive urea hydrolysis and beta-glucuronidase tests clearly distinguished it from closely related Staphylococcus spp. All analyses have consistently shown that the closest relative is Staphylococcus chromogenes; however, values of digital DNA-DNA hybridization <35.3% and an average nucleotide identity <81.4% confirmed that the analyzed strain is a distinct Staphylococcus species. Whole-genome sequencing and expert annotation of the genome revealed the presence of novel variable genetic elements, including two plasmids named pSR9025A and pSR9025B, prophages, genomic islands and a composite transposon that may confer selective advantages to other bacteria and enhance their survival. Based on phenotypic, phylogenetic and genomic data obtained in this study, the strain NRL/St 03/464T (= CCM 9025T = LMG 31873T = DSM 111348T) represents a novel species with the suggested name Staphylococcus ratti sp. nov.

Once a Known Veterinary Pathogen, Now a Forgotten Zoonosis. Case Report of An Invasive Staphylococcus intermedius Group Infection

Introduction: Staphylococcus intermedius group (SIG), a known veterinary pathogen with the potential for zoonotic human infections, comprises S. intermedius, S. pseudointermedius, and S. delphini, which are not easily distinguishable. Without the proper equipment and procedures, it cannot be distinguished from Staphylococcus aureus (SAu), which causes underestimation of its true incidence. Case Presentation: A 52-year-old male with diabetes presented with complaints of fever and malaise. He developed respiratory failure and altered mental status; hence, intensive care was provided to him. Blood cultures and bronchoalveolar lavage culture developed methicillin-resistant SIG. Despite rapid adjustment of empiric antibiotic therapy, he died of multiple organ failure. Conclusions: Incorporating knowledge about this new pathogen and its aggressiveness into daily clinical practice can, through a high index of suspicion and detailed anamnesis, reduce misdiagnoses.

Molecular characterization of oral bacteria isolated from human saliva

Periodontitis is an inflammation of gums and bones that supporting the teeth which caused by Staphylococcus intermedius. The saliva from a patient of periodontitis or suspect to periodontitis will have higher levels of Staphylococcus intermedius. Hence, human saliva is clinically informative in diagnosing oral disease and the oral health of an individual. In this study, oral bacteria in human saliva were identified using 16S ribosomal RNA. 16S ribosomal RNA (rRNA) genes from the isolated colonies were amplified through the colony Polymerase Chain Reaction (PCR) method. 16S rRNA genes were used to determine species identity by sequencing and generating the phylogenetic tree. The results showed that Streptococcus sp. and Staphylococcus sp. were the most prevalent oral bacteria found from all the saliva samples, while Lactobacillus sp. was found from two samples. From the constructed phylogenetic trees, bacteria strains B1 and B2 clustered with the Staphylococcus sp. database. Bacteria strains B9 and B10 were categorized as Streptococcus sp. as the confidential level between Streptococcus sp. database is 100% in Neighbour-Joining tree. Sample B15 and B16 clustered with Lactobacillus sp. database. Oral bacteria species typically associated with periodontitis was detected in all saliva samples. Therefore, it is important to fully understand the nature of the oral bacteria before further research on drug design and administration of oral treatment is executed.

Antibacterial effect of acidic ionized water on horse wounds bacterial isolates

Background and Aim: Horse wounds can be easily infected with bacteria depending on the nature of its cause such as laceration, abrasion, or puncture as well as the nature of its environment. Various treatments are available in managing open wounds, including the usage of topical antibiotics and antiseptics. However, antibiotic resistance has been a major concern attributed with chronic wound infection. The aim of this study was to test the efficacy of ionized water at different pH against the growth of common bacteria from horse wounds. Materials and Methods: Ten swab samples from equine infected wounds were collected and bacteria isolation and identification were performed. The antibacterial effect of the ionized water of pH 2.5, 4.5, 7.0, and 11.5 was tested on Staphylococcus aureus, Staphylococcus pseudintermedius, Staphylococcus intermedius, Escherichia coli, Pantoea agglomerans, and Klebsiella pneumoniae. The time-kill profiles of the ionized waters were determined at time 0, 2, 4, 6, and 8 h. Results: Ionized water of pH 2.5 and 4.5 showed antibacterial activity against S. aureus, S. pseudintermedius, and S. intermedius with significant (p>0.05) reduction in colony-forming unit/mL within 2-8 h. The degree of bactericidal effect of the acidic ionized water differs between the species with S. intermedius more susceptible. However, there was no antibacterial effect at pH 2.5, 4.5, 7.0, and 11.5 on the Gram-negative bacteria tested. Conclusion: Ionized water of pH 2.5 and 4.5 is effective in minimizing the growth of Gram-positive bacteria; thus it could be of clinical importance as an antiseptic for surface wound lavage in horses.

Eficacia de florfenicol para el tratamiento de pioderma por Staphylococcus intermedius en perros

El objetivo del presente trabajo fue evaluar el efecto del tratamiento con florfenicol en las dosis de 10 y 20 mg/kg administrados por vía IM, en el tratamiento de la pioderma canina por Staphylococcus intermedius, utilizando el modelamiento farmacocinético/farmacodinámico (PK/PD). Se hizo una simulación de Monte Carlo de los parámetros farmacocinéticos y farmacodinámicos y luego se realizó el análisis PK/PD para determinar las tasas de eficacia en el tratamiento de la infección bacteriana, según la concentración inhibitoria mínima (CIM) del S. intermedius, utilizando el intervalo entre 0.25 y 2 µg/ml. Las probabilidades de obtener el índice de erradicación bacteriológica con la dosis de 10 mg/kg fue de 97, 77, 7 y 1%, y con la dosis de 20 mg/kg fue de 95, 87, 61 y 7%, según las CIMs bacterianas de 0.25, 0.5, 1 y 2 µg/ml, respectivamente. La probabilidad de obtener la cura bacteriológica después del tratamiento con la dosis de 10 mg/kg disminuyó de forma significativa para infecciones causadas por microrganismos con CIM superior a 0.5 µg/ml (p<0.01), mientras que para la dosis de 20 mg/kg fue con CIM mayor de 1 µg/ml (p<0.01). El resultado evidencia la necesidad de incorporar en el protocolo terapéutico el aislamiento bacteriológico, la determinación de la CIM y la optimización de dosis terapéuticas basadas en la susceptibilidad bacteriana a fin de evitar fallas en terapéuticas y, consecuentemente, el incremento del desarrollo de resistencia microbiana.

Staphylococcal cassette chromosome mec elements from Staphylococcus intermedius group (SIG) isolates from dogs in a center for veterinary diagnostics in Brazil

ABSTRACT: Methicillin resistance in the Staphylococcus intermedius group (SIG) has emerged in small animal practice. Methicillin-resistant SIG (MRSIG) members have been implicated as causes of infections in both companion animals and humans. Staphylococcal cassette chromosome mec (SCCmec) elements carry the mecA/C genes, which encode for the transpeptidase PBP2a (PBP2’) responsible for β-lactam antibiotic resistance in staphylococci. This study examined the SCCmec types of MRSIG isolates from different clinical specimens of dogs that exhibited methicillin MIC ≥ 0.5 μg/mL by an automated identification and susceptibility system in a Center for Veterinary Diagnostics in São Paulo, Brazil. Susceptibility to methicillin was determined by broth microdilution testing, and Oxoid® M.I.C.Evaluator® strips. PBP2a production was detected using a latex agglutination assay. SCCmec typing was performed according to the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC) guidelines. SCCmec type II (2A), SCCmec type III (3A), composite SCC structures consisting of a class A mec gene complex in addition to multiple ccr gene complexes, and non-typable SCCmec elements were reported in these MRSIG isolates. SCCmec type variants differing from those so far acknowledged by IWG-SCC were found, indicating new rearrangements in the genetic context of mecA in these canine MRSIG isolates.

Staphylococcus pseudintermedius: Is it a real threat to human health?

Staphylococcus Intermedius Group (SIG) staphylococci, especially Staphylococcus pseudintermedius (S. pseudintermedius), share many features with the common human Staphylococcus aureus. The similarities concern both the phenotypic characteristics and virulence of the bacteria. It is a cause of difficulties in identifying the species of isolated staphylococci. Until now, S. pseudintermedius was considered a typically animal species, of marginal importance for humans. However, it is likely that the incidence of this staphylococcus in humans is underestimated due to the misidentification of S. pseudintermedius strains as S. aureus. The cases of infections caused by S. pseudintermedius both in humans and animals described so far in the literature show that these bacteria have a similar pathogenic potential. S. pseudintermedius also produces virulence factors that favor colonization of various body regions and infections, and may affect the species composition of the natural microbiota and the host’s immune response mechanisms. Also, S. pseudintermedius may show the ability to grow in the form of a biofilm, which significantly impedes effective antibiotic therapy in clinical practice. Due to its zoonotic potential, S. pseudintermedius deserves the attention of physicians and animal owners.

In vitro antibiotic resistance of Staphylococci isolated from different animal species

The purpose of this study is to investigate resistance to antibiotics of Staphylococcus species isolated from various samples belonging to different animal species. Among 48 Staphylococcus spp. strains, Staphylococcus intermedius was the most common species, followed by S. aureus, S. epidermidis, S. hyicus, S. saprophyticus. In a total of 48 Staphylococcus strains, the highest antibiotic resistance was observed to oxacillin (79.17%), tetracycline (39.58%), and ampicillin and cefoxitin (31.25%). Of 48 Staphylococcus strains, 42 showed resistance to at least one antimicrobial agent, while 23 of the strains had multidrug resistance. Antimicrobial resistance to tetracycline and ampicillin, erythromycin, streptomycin was detected frequently in S. aureus,S. intermedius, and S. epidermidis, respectively. Resistance rates for ampicillin, cefoxitin, and enrofloxacin were determined as 66.67% in S. hyicus strains. S. saprophyticus was determined to show resistance to 13 antibiotics other than meropenem. The highest antibiotic resistance was determined in S. aureus, S. intermedius, S. epidermidis, and in 48 Staphylococcus strains to oxacillin. Consequently, this study revealed resistance to various antibiotics in Staphylococcus species. Additionally, the presence of high oxacillin resistance and multidrug resistance in the Staphylococcus strains revealed the importance of determination of antimicrobial susceptibility before treatment and for rational use of antibiotics.

Staphylococcus intermedius Brain Abscess as a Complication of Pulmonary Arteriovenous Malformation in a Patient With Hereditary Hemorrhagic Telangiectasia

Staphylococcus intermedius is a rare cause of human infections ranging from skin and soft tissue infections to bacteremia. It is particularly known for its association with exposure to dogs. We report an unusual case of a 73-year-old female with a brain abscess caused by S intermedius who was recently diagnosed with hereditary hemorrhagic telangiectasia and a pulmonary arteriovenous malformation. The patient underwent debridement of the brain abscess followed by a 6-week course of vancomycin and rifampin, after which she made a near complete recovery. This is the first case of a brain abscess in an adult due to S intermedius in the published literature, and we provide a comprehensive review of the literature of all human infections caused by this pathogen and summarize its clinical manifestations, treatment recommendations, and outcomes.