New Gene Responsible for Resistance of Clinical Corynebacteria to Macrolide, Lincosamide and Streptogramin B.

The subject of the study was phenotypic marking of the antibiotic susceptibility and MLSB resistance mechanism in Corynebacterium spp. isolated from human skin (18 isolates) and from clinical materials (19 isolates). The strains were tested for the presence of the erm(A), erm(B), erm(C), erm(X), lnu(A), msr(A), msr(B) and mph(C) genes. Clinical isolates showed wide resistance to antibiotics. In 89% clinical isolates and 72% skin microbiota a constitutive type of MLSB resistance was found. In 12 clinical isolates the erm(C) gene was detected-eight of which had erm(X) as well as erm(C), two harboured erm(X), erm(C) and erm(A) and two demonstrated only erm(C).

[Animal Staphylococcus felis with the potential to infect human skin]. / Zwierzecy Staphylococcus felis o potencjale zakazania skóry czlowieka.

INTRODUCTION: Breaking interspecies barrier by microorganisms has become in the recent years an alarming phenomenon that threatens public health worldwide. An important potential interspecies transmission risk factor is close contact animal-human including occupational exposure of pet breeders and veterinarians. MATERIAL AND METHODS: The features of Staphylococcus felis ZMF 13 strain isolated from a swab from a cat's wound connected with potential pathogenicity were investigated. Results: The virulence factors of strain found were hydroxamate siderophores, production of invasins - intracellular proteolytic and lipolytic enzymes and the ability of biofilm production. The ability of bacteriocin-like substance production was also observed. The substance has an antagonistic activity against bacteria belong to physiological flora of the human skin which may be important in breaking the colonization resistance of human organism. Although the strain of S. felis ZMF 13 was methicillin-susceptible it demonstrated the constutive type of MLSB resistance mechanism. The genes ermA, msrB, linA connected with macrolide, lincosamides and streptogramin B resistance were detected. CONCLUSIONS: The current evidence suggest that Staphylococcusfelis has a number of features that can be crucial in its potential interspecies transmission.

Cohabitation--relationships of corynebacteria and staphylococci on human skin.

Skin microbiome main cultivable aerobes in human are coagulase-negative staphylococci and lipophilic corynebacteria. Staphylococcus strains (155) belonging to 10 species and 105 strains of Corynebacterium belonging to nine species from the skin swabs of healthy male volunteers were investigated to determine their enzymatic activity to main metabolic substrates: carbohydrates, proteins, lipids, and response to factors present on the skin such as osmotic pressure, pH, and organic acids. The results showed that lipophilic corynebacteria have different capacity for adaptation on the skin than staphylococci. Most of Corynebacterium spp. expressed lack of proteinase, phospholipase, and saccharolytic enzymes activity. Corynebacteria were also more sensitive than Staphylococcus spp. to antimicrobial agents existing on human skin, especially to low pH. These characters can explain domination of Staphylococcus genera on healthy human skin. It can be suggested that within these two bacterial genus, there exists conceivable cooperation and reciprocal protection which results in their quantitative ratio. Such behavior must be considered as crucial for the stability of the population on healthy skin.

Macrolide, lincosamide, and streptogramin B resistance in lipophilic Corynebacteria inhabiting healthy human skin.

Corynebacteria exist as part of human skin microbiota. However, under some circumstances, they can cause opportunistic infections. The subject of the study was to examine the macrolide-lincosamide-streptogramin B (MLSB) antibiotic resistance in 99 lipophilic strains of Corynebacterium genus isolated from the skin of healthy men. Over 70% of the tested strains were resistant to erythromycin and clindamycin. All of which demonstrated a constitutive type of MLSB resistance mechanism. In all strains, there were being investigated the erm(A), erm(B), erm(C), erm(X), lin(A), msr(A), and mph(C) genes that could be responsible for the different types of resistance to marcolides, lincosamides, and streptogramin B. In all strains with the MLSB resistance phenotype, the erm(X) gene was detected. None of the other tested genes were discovered. Strains harboring the erm(X) gene were identified using a phenotypic method based on numerous biological and biochemical tests. Identification of the chosen strains was compared with the results of API Coryne, MALDI-TOF MS, and 16S rDNA sequencing methods. Only 7 out of the 23 investigated resistant strains provided successful results in all the used methods, showing that identification of this group of bacteria is still a great challenge. The MLSB resistance mechanism was common in most frequently isolated from healthy human skin Corynebacterium tuberculostearicum and Corynebacterium jeikeium strains. This represents a threat as these species are also commonly described as etiological factors of opportunistic infections.

[Influence of substances produced by lipophilic Corynebacterium CDC G1 ZMF 3P13 on the microorganisms inhabiting human skin]. / Oddzialywanie substancji wydzielanych przez lipofilny szczep Corynebacterium CDC G1 ZMF 3P13 na inne drobnoustroje bytujace na skórze czlowieka.

Lipophilic species of Corynebacterium inhabiting skin as residents produces substances that can regulate the composition of natural flora. Research that was carried out concerned an influence of the substances produced by Corynebacterium CDC G1 ZMF 3P13 on the set of 22 bacterial strains (Staphylococcus spp., Corynebacterium spp., Propionibacterium spp.) mutually existing on the skin and the set of 6 Candida spp. isolated from patients. It was found out that the strain gives off into environment a mixture of substances with opposite effects. In the course of research an inhibiting substance (BLIS) was isolated with its evident effect on S. aureus, S. epidermidis, C. diphtheriae i Propionibacterium spp.

[Influence of contact with hospital environment on sensitivity to antibiotics of lipophilic strains of Corynebacterium residing on human skin]. / Wplyw kontaktu ze srodowiskiem szpitala na wrazliwosc na antybiotyki i chemioterapeutyki lipofilnych szczepów Corynebacterium rezydujacych na skórze czlowieka.

Sensitivity of two groups of lipophilic corynebacteria strains of different species, which form stable residential flora on human skin, to therapeutically significant groups of antibiotic was compared. Strains were isolated from people who did not have any contact with hospital environment, and from doctors closely connected with hospital. It was shown that strains isolated from doctors, which were in fact not under antibiotic pressure, were five times more multiresistant whilst at the same time being resistant to antibiotics used only in hospital treatment.

[Production of antibacterial substances by resident corynebacteria isolated from human skin]. / Wytwarzanie substancji przeciwbakteryjnych przez maczugowce rezydujace na skórze czlowieka.

Coryneform bacteria, especially lipophilic species, form stable but not dominant population on a human skin. This position is probably controlled by secretion of bacteriocin-like substances, which act directly on coexisting bacteria. Among 118 investigated corynebacteria belonging to seven species/taxa and isolated from human skin, 90% possessed an ability to produce such substances. The spectrum of their activity was restricted to killing gram-positive bacteria, but along with corynebacteria it also covered cocci, with Staphylococcus aureus in this group. This feature was revealed better on low pH media (pH 5.6) and media with 1.5% NaCl for cocci, but on pH 7,4 for corynebacteria.

Hydrophobicity and biofilm formation of lipophilic skin corynebacteria.

Lipophilic corynebacteria isolated as natural flora of human skin were examined. Among 119 assayed strains 94% presented a hydrophobic cell surface and 75.6% were able to form biofilms. These attributes, as well as aggregation in liquid media, were statistically connected with each other and promote the developing of biofilms on solid surfaces. This was characteristic of all the lipophilic Corynebacterium species found on human skin that were examined in this study. C. jeikeium and CDC group G2 strains dominated in this population, and they could be responsible for investigated features in the whole lipophilic skin bacterial population. These two groups are the most common coryneform bacteria isolated from nosocomial infections and these attributes most likely promote them to cause opportunistic infections.