Methicillin Resistant Staphylococci Isolated from Goats and Their Farm Environments in Saudi Arabia Genotypically Linked to Known Human Clinical Isolates: a Pilot Study.

We conducted a pilot whole genome sequencing (WGS) study to characterize the genotypes of nine methicillin resistant staphylococci (MRS) isolates recovered from goats and their farm environments in Eastern Province, Saudi Arabia, between November 2019 to August 2020. Seven out of nine isolates were methicillin resistant Staphylococcus aureus (MRSA), and two were methicillin resistant Staphylococcus epidermidis (MRSE). All MRSA isolates possessed genotypes previously identified to infect humans, including isolates harboring ST6-SCCmec IV-t304 (n = 4), ST5-SCCmec VI- t688 (n = 2) and ST5-SCCmec V-t311 (n = 1). 2 MRSA isolates possessed plasmids that were genetically similar to those identified in S. aureus isolates recovered from humans and poultry. In contrast, plasmids found in three MRSA isolates and one MRSE isolate were genetically similar to those recovered from humans. All MRSA isolates harbored the host innate modulate genes sak and scn previously associated with human infections. The genotypes of MRSE isolates were determined as ST35, a well-known zoonotic sequence type and ST153, which has been associated with humans. However, the MRSE isolates were untypeable due to extra ccr complexes identified in their SCCmec elements. Moreover, we identified in ST153 isolate SCCmec element also harbored the Arginine Catabolic Mobile Element (ACME) IV. All MRS isolates were phenotypically resistant to trimethoprim-sulfamethoxazole, an antibiotic for the decolonization of MRS. Three isolates carried antibiotic resistance genes in their SCCmec elements that were not previously described, including those encoding fusidic acid resistance (fusC) and trimethoprim resistance (dfrC) incorporated in the MRSA SCCmec VI. IMPORTANCE Our findings demonstrate a possible cross-transmission of methicillin resistant staphylococci between goats and their local environments and between goats and humans. Due to ever increasing resistance to multiple antibiotics, the burden of MRS has a significant impact on livestock farming, public health, and the economy worldwide. This study highlights that implementing a holistic approach to whole genome sequencing surveillance in livestock and farm environments would aid our understanding of the transmission of methicillin resistant staphylococci and, most importantly, allow us to implement appropriate infection control and hygiene practices.

Persistence of Staphylococcus spp. in milk from cows undergoing homeopathy to control subclinical mastitis.

BACKGROUND: Mastitis is one of the major diseases in dairy cattle, as it causes great economic losses to producers due to the reduction of milk production and changes in the quality of the product. The disease is mainly caused by bacteria of the genus Staphylococcus spp., these microorganisms can express various virulence factors, such as biofilms for example. In herds with organic management, producers and technicians use unconventional ways to treat and control the disease, such as homeopathy. However, it is not known if this type of treatment is able to control pathogenic bacteria such as those of the genus Staphylococcus, of relevance to animal and human health. Thus, the objective of this study was to investigate the production of biofilm in vitro and its genes by Staphylococcus spp. isolated in the milk of cows treated with homeopathy, as well as the persistence of microorganisms in animals. METHODS: Ninety-nine isolates of Staphylococcus spp. from cows treated and not treated with homeopathy were identified by internal transcribed space-polymerase chain reaction and investigated for the presence of the icaABCD, bap, aap, atlE, and bhp genes and in vitro biofilm production using the adhesion method on polystyrene plates. The enzyme restriction profile was determined by Pulsed-Field Gel Electrophoresis. Clusters of S. aureus and S. epidermidis with three or more isolates had an isolate selected for Multilocus Sequence Typing. RESULTS: The frequency of S. aureus isolations was similar in treated and untreated cows, while 71.4% of the coagulase-negative identified were isolated in cows treated with homeopathy. The distribution of the operon ica genes was similar in animals with and without treatment, except for the icaD gene, more frequent in treated cows. Production of biofilm was associated with presence of one or more genes from the icaADBC operon. S. aureus revealed a greater diversity and greater dissemination in cows treated and not treated with homeopathy. Sequence Types ST1, ST5, and ST126 were identified in S. aureus. CONCLUSIONS: The presence of biofilm-associated genes and the in vitro production of biofilms, combined with the persistence of clonal profiles of Staphylococcus spp. demonstrate other forms of control for bovine mastitis should be researched for organic production herds.

Characterization of biofilms and antimicrobial resistance of coagulase-negative Staphylococcus species involved with subclinical mastitis.

Biofilm formation is a central feature to guarantee staphylococcal persistence in hosts and is associated with several diseases that are difficult to treat. In this research paper, biofilm formation and antimicrobial susceptibility were investigated in staphylococcal strains belonging to several species. These strains were isolated from the milk of cows with subclinical mastitis and most of them were coagulase-negative, with the prevalence of Staphylococcus chromogenes. High genetic diversity was observed among the strains by pulsed field gel electrophoresis. Antimicrobial resistance was assessed by disk diffusion and more than 50% of the strains were resistant to ampicillin and penicillin G, with multi-resistance profiles (13.6%) also being observed. Most strains (65.9%) formed biofilms when cultivated in BHI supplemented with 1% glucose. Most strains (72.7%) carried the intercellular adhesion gene (icaA), while less than half (36.3%) carried the biofilm-associated protein gene (bap). Concentrations of up to 10xMIC of erythromycin and tetracycline were not sufficient to suppress cell viability in preformed biofilms. Our results revealed that a genetically diverse group of biofilm-forming Staphylococcus species can be involved in subclinical mastitis. Since high antimicrobial concentrations cannot eradicate biofilm cells in vitro, their use in dairy animals may be ineffective in controlling infections, while supporting selection of resistant microorganisms. These data reinforce the need for alternative therapies aiming at disrupting biofilms for effective disease control.

Symbiont Genomic Features and Localization in the Bean Beetle Callosobruchus maculatus.

A pervasive pest of stored leguminous products, the bean beetle Callosobruchus maculatus (Coleoptera: Chrysomelidae) associates with a simple bacterial community during adulthood. Despite its economic importance, little is known about the compositional stability, heritability, localization, and metabolic potential of the bacterial symbionts of C. maculatus. In this study, we applied community profiling using 16S rRNA gene sequencing to reveal a highly conserved bacterial assembly shared between larvae and adults. Dominated by Firmicutes and Proteobacteria, this community is localized extracellularly along the epithelial lining of the bean beetle's digestive tract. Our analysis revealed that only one species, Staphylococcus gallinarum (phylum Firmicutes), is shared across all developmental stages. Isolation and whole-genome sequencing of S. gallinarum from the beetle gut yielded a circular chromosome (2.8 Mb) and one plasmid (45 kb). The strain encodes complete biosynthetic pathways for the production of B vitamins and amino acids, including tyrosine, which is increasingly recognized as an important symbiont-supplemented precursor for cuticle biosynthesis in beetles. A carbohydrate-active enzyme search revealed that the genome codes for a number of digestive enzymes, reflecting the nutritional ecology of C. maculatus. The ontogenic conservation of the gut microbiota in the bean beetle, featuring a "core" community composed of S. gallinarum, may be indicative of an adaptive role for the host. In clarifying symbiont localization and metabolic potential, we further our understanding and study of a costly pest of stored products. IMPORTANCE From supplementing essential nutrients to detoxifying plant secondary metabolites and insecticides, bacterial symbionts are a key source of adaptations for herbivorous insect pests. Despite the pervasiveness and geographical range of the bean beetle Callosobruchus maculatus, the role of microbial symbioses in its natural history remains understudied. Here, we demonstrate that the bean beetle harbors a simple gut bacterial community that is stable throughout development. This community localizes along the insect's digestive tract and is largely dominated by Staphylococcus gallinarum. In elucidating symbiont metabolic potential, we highlight its possible adaptive significance for a widespread agricultural pest.

Antibiotic-resistant staphylococci from the wastewater treatment plant and grey-water samples in Obafemi Awolowo University, Ile-Ife, Nigeria.

This study examined the occurrence and molecular basis for antibiotic-resistant staphylococci from the wastewater treatment plant and grey-water samples in Obafemi Awolowo University, Nigeria. Standard microbiological techniques and molecular methods were utilized. The species identified (MALDI score >1.7) comprised S. saprophyticus (19), S. cohnii (8), S. sciuri (7), S. aureus (4), S. epidermidis (3), S. warneri (2), S. equorum (1), S. haemolyticus (1), S. nepalensis (1), S. condimenti (1), and S. pasteuri (1). Resistance to trimethoprim, tetracycline and cefoxitin were observed in 78.3% (47/60), 36.7% (22/60) and 25% (15/60) of the isolates, respectively. The rate of multidrug resistance was 53.3% (32/60) and observed in eight species from different sampling sites. Seven (S. sciuri; n = 5; S. aureus; n = 1; S. warneri; n = 1) of the 20 selected (representing the various staphylococcal species and antibiotypes) isolates were mecA-positive. Furthermore, the tetK gene was detected in nine isolates, six with dfrA, and four were positive for the dfrG gene. One S. aureus was mecA, tetK and dfrG gene positive. The study provides insights on antibiotic-resistant staphylococci from a non-clinical setting and highlights the need for active surveillance to understand the burden of antimicrobial resistance in Nigeria. This is key to improve synergy across the human, animal and environmental health sectors in Nigeria.

Antimicrobial activity of polypyrrole nanoparticles and aqueous extract of Moringa oleifera against Staphylococcus spp. carriers of multi-drug efflux system genes isolated from dairy farms.

Our objectives were to identify genes of the multi-drug efflux system and to evaluate the antimicrobial activities of polypyrrole nanoparticles (PPy-NPs) and aqueous extract of Moringa oleifera against Staphylococcus spp. isolated from dairy farms in Northeast Brazil. Initially, 162 Staphylococcus spp. isolates were subjected to in vitro antimicrobial sensitivity tests. Of these, 35 presented antimicrobial multi-drug resistance phenotypes. These 35 isolates were then referred for the detection of norA, norB, norC, msrA, mgrA, tet-38, and lmrS genes, all of which feature in multi-drug efflux systems. In the isolates carrying the genes, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PPy-NPs and Moringa oleifera aqueous extract were determined. In the molecular analysis of the 35 isolates norA, norC, tet-38, and msrA genes were detected and for the other genes norB, lmrS and mgrA there was no amplification. Antimicrobial activity was verified of PPy-NPs and aqueous extract of Moringa oleifera in Staphylococcus spp. carrying multi-drug efflux system genes. We concluded that there are multi-drug efflux system genes present in the Staphylococcus spp. from the agricultural environment in Northeast Brazil, and that aqueous extract of Moringa oleifera and PPy-NPs show bactericidal activity against these isolates.

Drought-tolerant and plant growth-promoting endophytic Staphylococcus sp. having synergistic effect with silicate supplementation.

Endophytic bacteria have been reported to have symbiotic, mutualistic, commensalistic or trophobiotic relationships with various plant parts. As part of its adaptation, many endophytic organisms are known to exhibit properties with multiple beneficial effects to the plant system. Even though many bacterial genera have been identified to have endophytic association, isolation of those which were previously demonstrated well for human association is quite interesting. In the study, endophytic bacteria Ceb1 isolated from the rhizome of Curcuma longa was identified by 16S rDNA sequencing as Staphylococcus sp. Further, Ceb1 was observed to have the ability to tolerate drought stress. While screening for the plant growth-promoting traits, Ceb1 was found to be positive for IAA production both under drought-stressed and normal conditions as confirmed by HPLC. The Ceb1 priming with Vigna unguiculata was observed to enhance the growth parameters of the plant. Analysis of Ceb1-treated plants by ICP-MS further showed modulation of both macro- and micronutrients. Upon drought stress induction in Vigna unguiculata, Ceb1 was found to provide synergistic plant growth-promoting effect to the plant along with the supplemented silicate sources. Under the changing agroclimatic conditions, exploring the plant stress-alleviating effects of endophytes is highly significant.

In vitro activity of meropenem/piperacillin/tazobactam triple combination therapy against clinical isolates of Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus pseudintermedius and vancomycin-resistant Enterococcus spp.

OBJECTIVES: To evaluate the activity of the reported synergistic and collaterally sensitive antibiotic combination, meropenem/piperacillin/tazobactam (ME/PI/TZ), against a panel of methicillin-resistant Staphylococcus aureus (MRSA) and other methicillin-resistant Staphylococcus species; and to investigate the relationship between ME/PI/TZ susceptibility and the genomic background of clinical isolates of MRSA. METHODS: ME/PI/TZ combination and single drug minimum inhibitory concentrations (MICs) were determined for 207 strains (including 121 MRSA, 4 methicillin-sensitive S. aureus [MSSA], 37 vancomycin-intermediate S. aureus [VISA], 6 ceftaroline non-susceptible MRSA, 29 coagulase-negative staphylococci [CoNS], 5 S. pseudointermedius and 5 vancomycin-resistant Enterococci [VRE]) by broth microdilution. Whole genomes of 168 S. aureus strains were sequenced, assembled, and comparatively analysed. RESULTS: USA300-SCCmec type IV isolates, clonal complex 8 (CC8)-MRSA isolates, including some VISA and ceftaroline (CPT)-intermediate strains, and all tested methicillin-resistant S. epidermidis isolates were highly susceptible to ME/PI/TZ. Isolates with elevated MICs (MICs of >16/16/16 mg/L) clustered with the USA100-SCCmec type II strain. Susceptibility of MRSA to ME/PI/TZ was correlated with susceptibility to ME. No obvious cross-resistance to CPT was observed among high-ME/PI/TZ MIC isolates. CONCLUSIONS: The ME/PI/TZ combination is effective against a variety of clinical MRSA isolates, particularly of the USA300 lineage, which is expanding worldwide. ME/PI/TZ is also effective against drug-resistant CoNS and S. pseudintermedius clinical isolates.

Collaboration between an antimicrobial stewardship team and the microbiology laboratory can shorten time to directed antibiotic therapy for methicillin-susceptible staphylococcal bacteremia and to discontinuation of antibiotics for coagulase-negative staphylococcal contaminants.

BACKGROUND: Rapid identification of Gram-positive cocci in clusters (GPCC) in positive blood cultures (pBC) may limit exposure to unnecessary or inappropriate antibiotics. METHODS: Inpatients with pBC showing GPCC between October 2013 and December 2017 were included. In the baseline period (BL), final ID and susceptibility results were reported in the electronic medical record (EMR) within 48 h of telephoned Gram stain report. The laboratory introduced rapid phenotypic identification and direct susceptibility testing (INT1), later replaced by PCR (INT2). In the last Intervention (INT3), Antimicrobial Stewardship Response Team (ASRT) contacted providers with PCR results and recommendations. RESULTS: Time to directed therapy (TDT) for MSSA and coagulase-negative Staphylococci (CoNS) decreased from BL to INT3 (48.5-17.9 h, 50.3-16.4 h, respectively). Time to ID from BL to INT3 for MSSA and CoNS also decreased (23.2-1.9 h, 44.7-2.8, respectively). CONCLUSIONS: TDT can be improved by modification of reporting methods with utilization of an ASRT.

Impact of systemic antimicrobial therapy on mucosal staphylococci in a population of dogs in Northwest England.

BACKGROUND: Antimicrobial-resistant bacteria are increasingly isolated from veterinary patients. OBJECTIVES: To determine risk factors for antimicrobial resistance (AMR) among canine mucosal staphylococci following routine antimicrobial treatment with cefalexin (CFX), clavulanate-amoxicillin (AC), cefovecin (CVN), clindamycin (CD) or a fluoroquinolone (FQ). ANIMALS: Mucosal swab samples (n = 463) were collected from 127 dogs pre-treatment, immediately, and at one- and three-months post-treatment. METHODS: Staphylococci were identified phenotypically and biochemically as coagulase negative (CoNS) or coagulase positive (CoPS); CoPS were speciated by nuc gene PCR. Antimicrobial susceptibility was determined using disc diffusion and mecA gene carriage by PCR. Multilevel, multivariable models examined associations between risk factors and presence/absence of CoPS, meticillin resistance (MR), multidrug-resistance (MDR) and fluoroquinolone resistance (FQR). RESULTS: The percentage of samples with CoNS increased and with CoPS (including S. pseudintermedius) decreased immediately post-treatment with CFX, CVN and CD (P ≤ 0.001) and one month post-treatment with CD (P = 0.003). By three months post-treatment, there was no significant difference compared to pre-treatment samples. Immediately post-treatment with FQs there was significantly increased risk of isolating MRS (P = 0.002), MDR (P = 0.002) or FQR (P = 0.013) staphylococci and of MDR following CFX treatment (P = 0.019). The percentage of samples with AMR staphylococci declined from immediately to three months post-treatment and there was no significant difference between resistance prevalence at one or three months post-treatment for most AMR traits and treatment groups. Exceptions include increased MDR following FQ (P = 0.048) or CFX (P = 0.021), at one and three months post-treatment, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Systemic antimicrobials impact on mucosal staphylococci. Immediately after therapy, the mucosa may be a reservoir for AMR staphylococci that are a source of mobile genetic elements carrying AMR genes.

Antimicrobial Susceptibility and Enterotoxin-Encoding Genes in Staphylococcus spp. Recovered from Kitchen Equipment from a University Hospital in Rio de Janeiro, Brazil.

This study was conducted to determine the occurrence of antimicrobial resistance and enterotoxin-encoding genes (EEGs) in Staphylococcus spp. recovered from equipment used to prepare hospital meals, in a university hospital in Rio de Janeiro, Brazil. Sixty samples were collected from semi-industrial equipment (one blender and one mixer) in the hospital's kitchen. Resistance genes and SCCmec types were detected by PCR. From the 40 isolates of Staphylococcus spp. identified, 8 were Staphylococcus aureus. Thirty-two (80%) Staphylococcus spp. isolates were resistant to at least one antimicrobial agent. Resistance genetic determinants were detected: erm gene (Staphylococcus epidermidis [n = 2]; Staphylococcus hominis [n = 1]), mecA gene (S. epidermidis [n = 2]), and aa(6')-aph(2'') gene (Staphylococcus caprae [n = 1], S. epidermidis [n = 2], S. hominis [n = 1], Staphylococcus pausteri [n = 1], Staphylococcus simulans [n = 1], and Staphylococcus warneri [n = 1]). The presence of at least one EEG in 83% (n = 33) of the isolates was identified. Two strains of S. epidermidis were methicillin-resistant S. epidermidis (MRSE) and harboring SCCmec type IV. Staphylococcus spp. contaminated some hospital kitchen's equipment, indicating that hygiene procedures should be improved. Results also indicate that meals can be a vehicle to disseminate multiresistant Staphylococcus spp., including MRSE, and Staphylococcus with EEGs.

Antibiofilm activity of bioactive hop compounds humulone, lupulone and xanthohumol toward susceptible and resistant staphylococci.

Bacterial biofilms pose a serious medical problem due to their significant resistance to antimicrobials, and staphylococci are recognized as the most frequent cause of biofilm-associated infections. The hop plant (Humulus lupulus L.) contains substances that have been determined to act as anti-infective agents against bacteria, mainly in planktonic form. Therefore, we decided to investigate the antibiofilm properties of H. lupulus L.-derived compounds (humulone, lupulone and xanthohumol) against a selected group of Staphylococcus spp., including methicillin-susceptible and resistant strains. All tested hop compounds were shown to possess antimicrobial properties against all tested staphylococci, both planktonic and biofilm-dwelling, with no significant difference between resistant and susceptible strains. All compounds lowered the number of bacterial cells released from the biofilm, with the strongest effect seen for lupulone, followed by xanthohumol. Moreover, lupulone and xanthohumol were not only able to penetrate the biofilm and reduce the number of bacteria within it, but their higher concentrations (∼60 µg/mL for xanthohumol and ∼125 µg/mL for lupulone) reduced the number of surviving bacterial cells to zero.

Boesenbergia rotunda (L.) Mansf. extract potentiates the antibacterial activity of some ß-lactams against ß-lactam-resistant staphylococci.

OBJECTIVES: The purpose of this study was to investigate the effect of Boesenbergia rotunda (L.) Mansf. extract (BRE) and peptidoglycan inhibitor antibiotics, alone and in combination, against ß-lactam-resistant staphylococci. METHODS: Antibacterial and synergistic activities of BRE alone and in combination with ampicillin (AMP), cloxacillin (CLX), cefazolin (CZO) or vancomycin (VAN) were evaluated against two ß-lactam-resistant Staphylococcus aureus (BRSA) isolates and one ß-lactam-resistant Staphylococcus epidermidis (BRSE) isolate. The activities were confirmed by killing curve assays. The preliminary antimicrobial action was elucidated by transmission electron microscopy (TEM) and cytoplasmic membrane (CM) permeability assay. RESULTS: All tested staphylococci were inhibited by BRE at a minimum inhibitory concentration (MIC) of 16µg/mL. Two BRSA strains showed high resistance to CLX, AMP and CZO, whilst BRSE was resistant to CLX and AMP. All tested isolates remained susceptible to VAN. Chequerboard assay demonstrated a fractional inhibitory concentration index (FICI) of 0.50 for the BRE+CLX combination against the BRSA strains. Killing curve determinations confirmed the antibacterial and synergistic activities. TEM revealed collapse of the CM in BRE-treated cells and damage both of the CM and peptidoglycan (PG) in BRE+CLX-treated cells. The CM permeability assay showed that either BRE or nisin alone as well as BRE+CLX significantly induced leakage of OD260nm-absorbing materials. CONCLUSIONS: BRE potentiated the activity of ß-lactams, particularly CLX, against ß-lactam-resistant staphylococci by damaging the CM and PG layer, leading to leakage of intracellular material. Combination of BRE and ß-lactams provides a potential way forward in developing novel antistaphylococcal agents.

Preliminary data on antibacterial activity of Echinacea purpurea-associated bacterial communities against Burkholderia cepacia complex strains, opportunistic pathogens of Cystic Fibrosis patients.

Burkholderia cepacia complex bacteria (Bcc) represent a serious threat for immune-compromised patient affected by Cystic Fibrosis (CF) since they are resistant to many substances and to most antibiotics. For this reason, the research of new natural compounds able to inhibit the growth of Bcc strains has raised new interest during the last years. A source of such natural compounds is represented by medicinal plants and, in particular, by bacterial communities associated with these plants able to produce molecules with antimicrobial activity. In this work, a panel of 151 (endophytic) bacteria isolated from three different compartments (rhizospheric soil, roots, and stem/leaves) of the medicinal plant Echinacea purpurea were tested (using the cross-streak method) for their ability to inhibit the growth of 10 Bcc strains. Data obtained revealed that bacteria isolated from the roots of E. purpurea are the most active in the inhibition of Bcc strains, followed by bacteria isolated from the rhizospheric soil, and endophytes from stem/leaf compartment. At the same time, Bcc strains of environmental origin showed a higher resistance toward inhibition than the Bcc strains with clinical (i.e. CF patients) origin. Differences in the inhibition activity of E. purpurea-associated bacteria are mainly linked to the environment -the plant compartment- rather than to their taxonomical position.

Fighting Off Wound Pathogens in Horses with Honeybee Lactic Acid Bacteria.

In the global perspective of antibiotic resistance, it is urgent to find potent topical antibiotics for the use in human and animal infection. Healing of equine wounds, particularly in the limbs, is difficult due to hydrostatic factors and exposure to environmental contaminants, which can lead to heavy bio-burden/biofilm formation and sometimes to infection. Therefore, antibiotics are often prescribed. Recent studies have shown that honeybee-specific lactic acid bacteria (LAB), involved in honey production, and inhibit human wound pathogens. The aim of this pilot study was to investigate the effects on the healing of hard-to-heal equine wounds after treatment with these LAB symbionts viable in a heather honey formulation. For this, we included ten horses with wound duration of >1 year, investigated the wound microbiota, and treated wounds with the novel honeybee LAB formulation. We identified the microbiota using MALDI-TOF mass spectrometry and DNA sequencing. In addition, the antimicrobial properties of the honeybee LAB formulation were tested against all wound isolates in vitro. Our results indicate a diverse wound microbiota including fifty-three bacterial species that showed 90 % colonization by at least one species of Staphylococcus. Treatment with the formulation promoted wound healing in all cases already after the first application and the wounds were either completely healed (n = 3) in less than 20 days or healing was in progress. Furthermore, the honeybee LAB formulation inhibited all pathogens when tested in vitro. Consequently, this new treatment option presents as a powerful candidate for the topical treatment of hard-to-heal wounds in horses.

Dissemination of metal resistance genes among animal methicillin-resistant coagulase-negative Staphylococci.

The use of metals as feed supplement has been recognized as a potential driver for co-selection of methicillin-resistant Staphylococcus aureus in pigs. However, the prevalence of these determinants in methicillin-resistant coagulase-negative staphylococci (MRCoNS) is largely unknown. In this study, a collection of 130 MRCoNS from pigs and veal calves were investigated for the presence of metal-resistance genes (czrC, copB, cadD, arsA) associated to SCCmec. Near half of the isolates carried metal resistance genes (czrC 5.4%, copB 38.5%, cadD 7.7%, arsA 26.2%) regardless of their SCCmec type. The increased use of metals in livestock animals, especially zinc in pigs in several European countries may co-select for methicillin-resistance in several staphylococcal species.

Characterization of staphylococci in urban wastewater treatment plants in Spain, with detection of methicillin resistant Staphylococcus aureus ST398.

The objective of this study was to determine the prevalence of Staphylococcus in urban wastewater treatment plants (UWTP) of La Rioja (Spain), and to characterize de obtained isolates. 16 wastewater samples (8 influent, 8 effluent) of six UWTPs were seeded on mannitol-salt-agar and oxacillin-resistance-screening-agar-base for staphylococci and methicillin-resistant Staphylococcus aureus recovery. Antimicrobial susceptibility profile was determined for 16 antibiotics and the presence of 35 antimicrobial resistance genes and 14 virulence genes by PCR. S. aureus was typed by spa, agr, and multilocus-sequence-typing, and the presence of immune-evasion-genes cluster was analyzed. Staphylococcus spp. were detected in 13 of 16 tested wastewater samples (81%), although the number of CFU/mL decreased after treatment. 40 staphylococci were recovered (1-5/sample), and 8 of them were identified as S. aureus being typed as (number of strains): spa-t011/agr-II/ST398 (1), spa-t002/agr-II/ST5 (2), spa-t3262/agr-II/ST5 (1), spa-t605/agr-II/ST126 (3), and spa-t878/agr-III/ST2849 (1). S. aureus ST398 strain was methicillin-resistant and showed a multidrug resistance phenotype. Virulence genes tst, etd, sea, sec, seg, sei, sem, sen, seo, and seu, were detected among S. aureus and only ST5 strains showed genes of immune evasion cluster. Thirty-two coagulase-negative Staphylococcus of 12 different species were recovered (number of strains): Staphylococcus equorum (7), Staphylococcus vitulinus (4), Staphylococcus lentus (4), Staphylococcus sciuri (4), Staphylococcus fleurettii (2), Staphylococcus haemolyticus (2), Staphylococcus hominis (2), Staphylococcus saprophyticus (2), Staphylococcus succinus (2), Staphylococcus capitis (1), Staphylococcus cohnii (1), and Staphylococcus epidermidis (1). Five presented a multidrug resistance phenotype. The following resistance and virulence genes were found: mecA, lnu(A), vga(A), tet(K), erm(C), msr(A)/(B), mph(C), tst, and sem. We found that Staphylococcus spp. are normal contaminants of urban wastewater, including different lineages of S. aureus and a high diversity of coagulase-negative species. The presence of multiple resistance and virulence genes, including mecA, in staphylococci of wastewater can be a concern for the public health.

Telavancin: mechanisms of action, in vitro activity, and mechanisms of resistance.

Telavancin is a semisynthetic lipoglycopeptide derivative of vancomycin. Telavancin has a dual mechanism of antibacterial action, disrupting peptidoglycan synthesis and cell membrane function. In 2014, the Clinical and Laboratory Standards Institute (CLSI) revised the antimicrobial susceptibility testing method for telavancin, resulting in minimum inhibitory concentration (MIC) determinations that are more accurate and reproducible and demonstrate greater in vitro potency than shown with the previous testing method. The CLSI testing method changes coincided with revised telavancin MIC interpretive break point criteria for susceptibility approved by the US Food and Drug Administration for Staphylococcus aureus (≤0.12 µg/mL), Streptococcus pyogenes (≤0.12 µg/mL), Streptococcus agalactiae (≤0.12 µg/mL), Streptococcus anginosus group (≤0.06 µg/mL), and Enterococcus faecalis (vancomycin susceptible, ≤0.25 µg/mL). Telavancin is equally potent against methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). It demonstrates activity against isolates of heterogeneous vancomycin-intermediate S. aureus and vancomycin-intermediate S. aureus but is poorly active against vancomycin-resistant S. aureus. It also demonstrates potent activity against Staphylococcus epidermidis and Streptococcus spp. (MIC90 ≤0.03 µg/mL). Thus far, it has not been possible to select for high-level telavancin resistance in the laboratory using serially passaged clinical isolates of MRSA and MSSA.

Identification of compounds inhibiting the C-S lyase activity of a cell extract from a Staphylococcus sp. isolated from human skin.

UNLABELLED: The C-S lyase activity of bacteria in the human armpit releases highly malodorous, volatile sulfur compounds from nonvolatile precursor molecules. Such compounds significantly contribute to human body odour. Hence, C-S lyase represents an attractive target for anti-body-odour cosmetic products. Here, aiming at a final use in an ethanol-based deodorant formulation, 267 compounds and compound mixtures were screened for their ability to inhibit the C-S lyase activity of a Stapyhlococcus sp. crude extract. Staphylococcus sp. Isolate 128, closely related to Staphylococcus hominis, was chosen as the test bacterium, as it showed a reproducibly high specific C-S lyase activity on three different culturing media. Using a photometric assay and benzylcysteine as substrate, six rather complex, plant-derived compound mixtures and five well defined chemical compounds or compound mixtures were identified as inhibitors, leading to an inhibition of ≥70% at concentrations of ≤0·5% in the assay. The inhibition data have demonstrated that compounds with two vicinal hydroxyl groups or one hydroxyl and one keto group bound to an aryl residue are characteristic for the inhibition. The substances identified as C-S lyase inhibitors have the potential to improve the performance of anti-body-odour cosmetic products, for example, ethanol-based deodorants. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacterial C-S lyase represents one of the key enzymes involved in human body odour formation. The aim of this study was to identify compounds inhibiting the C-S lyase activity of a Staphylococcus sp. isolate from the human skin. The compounds identified as the best inhibitors are characterized by the following features: two vicinal hydroxyl groups or one hydroxyl and one keto group bound to an aryl residue. They might be used to improve the performance of cosmetic products aiming to prevent the formation of microbially caused human body odour, for example, ethanol-based deodorants.

Efficacy of anti-staphylococcal protein P128 for the treatment of canine pyoderma: potential applications.

In this study, we demonstrate the antibacterial activity of P128 on Staphylococcus isolates responsible for canine pyoderma. Eighty seven swabs were collected from dogs suffering from pyoderma and subjected to antibiotic sensitivity test and 46 Staphylococcus strains were isolated and characterized. In-vitro antimicrobial susceptibility testing with P128 was done by Minimum Inhibitory Concentration (MIC) method as per CLSI guidelines. All the Staphylococci isolated from the dogs with pyoderma, although showed resistance to various antibiotics tested, were lysed by P128. Clinical efficacy of P128 was examined in 17 dogs with pyoderma by application of the P128 hydrogel twice daily for 8 days and the results indicated complete healing of all the lesions of all the dogs under treatment. Under the conditions of this study, P128 was found to be a potent convenient proteinaceous drug for the treatment of staphylococcal pyoderma in dogs.