Antibiofilm activity of Cutibacterium acnes cell-free conditioned media against Staphylococcus spp

Staphylococcus spp. and Cutibacterium acnes are members of the skin microbiome but can also act as pathogens. Particularly, Staphylococcus species are known to cause medical devices-associated infections, and biofilm production is one of their main virulence factors. Biofilms allow bacteria to adhere and persist on surfaces, protecting them from antimicrobials and host defenses. Since both bacteria are found in the human skin, potentially competing for niches, we aimed to investigate if C. acnes produces molecules that affect Staphylococcus spp. biofilm formation and dispersal. Thus, we evaluated the impact of C. acnes cell-free conditioned media (CFCM) on S. aureus, S. epidermidis, S. hominis, and S. lugdunensis biofilm formation. S. lugdunensis and S. hominis biofilm formation was significantly reduced with C. acnes CFCM without impact on their planktonic growth. C. acnes CFCM also significantly disrupted S. hominis established biofilms. The active molecules against S. lugdunensis and S. hominis biofilms appeared to be distinct since initial characterization points to different sizes and sensitivity to sodium metaperiodate, although the activity is highly resistant to heat in both cases. Mass spectrometry analysis of the fractions active against S. hominis revealed several potential candidates. Investigating how species present in the same environment interact, affecting the dynamics of biofilm formation, may reveal clinically useful compounds as well as molecular aspects of interspecies interactions.

Prevalence and molecular analysis of Sarcocystis infections in cattle in Northwest Iran and the first global report of S. gigantea in cattle

Cattle are intermediate host for several species of Sarcocystis, including S. cruzi, S. hirsuta, and S. hominis with high prevalence worldwide. The present study aimed to determine the prevalence of Sarcocystis infection, species identification, and phylogenetic analysis of the parasite in cattle in Northwest Iran. The samples of diaphragm and esophagus from 290 cattle were collected from slaughterhouses in Northwest Iran and subjected to macroscopic, microscopic, and histopathology examinations, PCR-RFLP, sequencing and phylogenetic analyses. Tissue cysts of Sarcocystis spp. were detected in 92% of cattle by digestion and microscopic tests. Based on the PCR-RFLP and specific PCR, 87.9% and 1.03% of isolates were identified as S. cruzi, and S. hominis, respectively. Macrocyst was seen in a single sample that was identified as S. gigantea. The haplotype network exhibited the extension of the various haplotypes of S. cruzi between neighboring provinces in Northwest Iran. Heterogeneity analysis of S. cruzi 18S-rRNA sequences indicated genetic diversity among S. cruzi isolates (Haplotype diversity: 0.733-0.854) consisting 16 haplotypes; however, the nucleotide differences showed low diversity (0.01481 to 0.03351). Pair wise sequence distance matrix amongst S. cruzi sequences indicated an intra-species divergence of 0%-7.8% and identity of 92.6%-100%. Sarcocystis infection is highly prevalent in cattle in Northwest Iran, with the predominance of S. cruzi, and genetic variants of this species are unequivocally distributing in Northwest provinces. First global detection of S. gigantea in cattle reflects new insights of transmission dynamic and biology of this parasite in Iran.

Production and purification of anti-tubercular and anticancer protein from Staphylococcus hominis under mild stress condition of Mentha piperita L

The present study was investigated to purify and characterize anti-tubercular and anticancer protein from Staphylococcus hominis strain MANF2 under mild stress condition of Mentha piperita L. Initially, the in vitro anti-tubercular activity of strain MANF2 was determined against Mycobacterium tuberculosis H37Rv using luciferase reporter phage (LRP) assay which showed relative light unit reduction (RLU) of >90 %. Further, MTT test revealed promising in vitro anticancer trait of strain MANF2 against lung (A549) and colon (HT-29) cancer cell lines. Mild stress of M. piperita L. was provided to strain MANF2 at lag and log phase of its growth and the protein production was optimized statistically using central composite design of response surface methodology. Results showed enhanced protein production in the medium containing yeast extract (0.5 % w/v) and glycerol (1.5 % v/v), being supplemented with M. piperita L. (1.5 % v/v at log phase of strain MANF2. Protein was purified using standard purification techniques and showed single homogeneous band on SDS-PAGE with nominal molecular mass of 51293 Da, as confirmed by MALDI-TOF MS/MS. The N- amino acid sequencing showed homology with proline dehydrogenase (ProDH), thus, the protein was proposed to be new ProDH-like protein in S. hominis. Further, LRP test revealed concentration dependent (10-50 μg/mL) in vitro anti-tubercular properties of purified protein with significant RLU reductions of 36.8 ± 0.3-78.5 ± 0.4 %. The IC₅₀ values of purified protein against A549 and HT-29 cancer cells were calculated as 42.2 and 48.4 μg/mL, respectively. In conclusion, protein purified from strain MANF2 under mild stress of M. piperita L can certainly be implied as efficacious anti-tubercular and anticancer agents in future.

Anti-quorum Sensing Activities of Selected Coral Symbiotic Bacterial Extracts From the South China Sea

The worldwide increase in antibiotic-resistant pathogens means that identification of alternative antibacterial drug targets and the subsequent development of new treatment strategies are urgently required. One such new target is the quorum sensing (QS) system. Coral microbial consortia harbor an enormous diversity of microbes, and are thus rich sources for isolating novel bioactive and pharmacologically valuable natural products. However, to date, the versatility of their bioactive compounds has not been broadly explored. In this study, about two hundred bacterial colonies were isolated from a coral species (Pocillopora damicornis) and screened for their ability to inhibit QS using the bioreporter strain Chromobacterium violaceum ATCC 12472. Approximately 15% (30 isolates) exhibited anti-QS activity, against the indicator strain. Among them, a typical Gram-positive bacterium, D11 (Staphylococcus hominis) was identified and its anti-QS activity was investigated. Confocal microscopy observations showed that the bacterial extract inhibited the biofilm formation of clinical isolates of wild-type P. aeruginosa PAO1 in a dose-dependent pattern. Chromatographic separation led to the isolation of a potent QS inhibitor that was identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) spectroscopy as DL-homocysteine thiolactone. Gene expression analyses using RT-PCR showed that strain D11 led to a significant down-regulation of QS regulatory genes (lasI, lasR, rhlI, and rhlR), as well as a virulence-related gene (lasB). From the chemical structure, the target compound (DL-homocysteine thiolactone) is an analog of the acyl-homoserine lactones (AHLs), and we presume that DL-homocysteine thiolactone outcompetes AHL in occupying the receptor and thereby inhibiting QS. Whole-genome sequence analysis of S. hominis D11 revealed the presence of predicted genes involved in the biosynthesis of homocysteine thiolactone. This study indicates that coral microbes are a resource bank for developing QS inhibitors and they will facilitate the discovery of new biotechnologically relevant compounds that could be used instead of traditional antibiotics.

Enhancement of anti-tubercular activity and biomass of fermented food associated Staphylococcus hominis strain MANF2 using Taguchi orthogonal array and Box-Behnken design

The prime focus of the present investigation was to optimize statistically the anti-tubercular activity and biomass of fermented food associated Staphylococcus hominis strain MANF2 using Taguchi orthogonal array (OA) and Box-Behnken design (BBD). The anti-tubercular activity of strain MANF2 was determined against Mycobacterium tuberculosis H37Rv using luciferase reporter phase assay. Among varied media examined, the isolate exhibited impressive anti-tubercular activity with paramount relative light unit reduction of >90% in de Man Rogose Sharpe (MRS) broth. Primarily, the anti-tubercular activity and biomass of strain MANF2 were estimated in MRS broth by optimizing eight diversified parameters using one factor at a time (OFAT) method after working out a series of experiments. The most significant contributing factors selected through OFAT tool were optimized using Taguchi approach with a standard OA layout of L18 (2² × 3⁶). Results demonstrated the significant (P ≤ 0.05) influence of pH, temperature, yeast extract, magnesium sulphate, and glycerol on response variables. These controlled variables were further optimized using BBD matrix at N = 46 by second-order polynomial equation. The fermentation medium of pH 6.5 constituting yeast extract (0.5% w/v), magnesium sulphate (0.1% w/v), and glycerol (1.5% v/v), being further incubated at 30 °C showed enhanced anti-tubercular activity (98.7%) and approximately 4 fold increment in the bacterial biomass yield (8.3 mg/mL) with respect to traditional OFAT method. Three-dimensional response plots of the quadratic model showed interdependent interaction between the significant variables. In conclusion, the present study revealed the first report on the optimization of anti-tubercular activity and biomass of S. hominis via Taguchi OA as well as BBD design, and thus, paved a path for its proficient applications in pharmaceutical industries as dynamic mycobactericidal agent in future.

Molecular differentiation of bovine sarcocysts

Cattle are common intermediate hosts of Sarcocystis, and the prevalence in adult bovine muscle is close to 100 % in most regions of the world. Three Sarcocystis spp. are known to infect cattle as intermediate hosts, namely, S. cruzi, S. hirsuta, and S. hominis. The aim of the present study was the molecular identification and differentiation of these three species, Neospora caninum and Besnoitia by PCR and RFLP methods. Tissue samples were obtained from diaphragmatic muscle of 101 cattle slaughtered in Shiraz, Fars Province, Iran, for both smear preparation and DNA extraction. The samples were digested by Pepsin, washed three times with PBS solution before taking smears, fixed in absolute methanol and stained with 10 % Giemsa. The slides were examined microscopically for Sarcocystis bradyzoites and DNA was extracted from 100 mg of Sarcocystis-infected meat samples. Since the primers also bind to 18S rRNA gene of some tissue cyst-forming coccidian protozoa, DNA was also extracted from 100 μl of tachyzoite-containing suspension of N. caninum and Besnoitia isolated from goat to compare RFLP pattern. Polymerase chain reaction (PCR) was performed on DNA of samples which were microscopically positive for Sarcocystis. Five restriction enzymes Dra1, EcoRV, RsaI, AvaI, and SspI were used for RFLP and DNA of one sample from protozoa was sequenced. Based on the RFLP results, 87 (98.9 %) DNA samples were cut with DraI, indicating infection by S. cruzi. One sample (1.1 %) of PCR products of infected samples was cut only with EcoRV which showed S. hominis infection. Forty-eight samples (53.3 %) of PCR products were cut with both DraI, EcoRV, or with DraI, EcoRV, and RsaI while none of them was cut with SspI, which shows the mixed infection of both S. cruzi and S. hominis and no infection with S. hirsuta. It seems by utilizing these restriction enzymes, RLFP could be a suitable method not only for identification of Sarcocystis species but also for differentiating them from N. caninum and Besnoitia.

Anti-breast cancer effects of live, heat-killed and cytoplasmic fractions of Enterococcus faecalis and Staphylococcus hominis isolated from human breast milk

Development of tumour that is resistant to chemotherapeutics and synthetic drugs, coupled with their life-threatening side effects and the adverse effects of surgery and hormone therapies, led to increased research on probiotics' anticancer potentials. The current study investigated the potential of live, heat-killed cells (HKC) and the cytoplasmic fractions (CF) of Enterococcus faecalis and Staphylococcus hominis as anti-breast cancer agents. MCF-7 cell line was treated with 25, 50, 100 and 200 μg/mL each of live, HKC and CF of the bacteria; and cytotoxicity was evaluated for 24, 48 and 72 h using MTT assay. The morphological features of the treated cells were examined by fluorescence microscopy. The stage of cell cycle arrest and apoptosis were quantified by flow cytometry. The bacterial effect on non-malignant breast epithelial cell line, MCF-10A, was assessed using MTT assay for 24, 48 and 72 h. All the three forms of the bacteria caused a significant decrease in MCF-7 (up to 33.29%) cell proliferation in concentration- and time-dependent manner. Morphological features of apoptosis like cell death, cell shrinkage and membrane blebbing were observed. Flow cytometry analyses suggested that about 34.60% of treated MCF-7 was undergoing apoptosis. A strong anti-proliferative activity was efficiently induced through sub-G1 accumulation (up to 83.17%) in treated MCF-7 and decreased number in the G0/G1 phase (74.39%). MCF-10A cells treated with both bacteria showed no significant difference with the untreated (>90% viability). These bacteria can be used as good alternative nutraceutical with promising therapeutic indexes for breast cancer because of their non-cytotoxic effects to normal cells.

Sarcocystis Spp. Prevalence in Bovine Minced Meat: A Histological and Molecular Study

Sarcosporidiosis is caused by ingestion of contaminated raw or undercooked bovine meat and, although considered a minor zoonosis, it can represent a threath for immunocompromised people. Aim of this study was to determine the prevalence of Sarcocystis spp. in bovine minced meat intended for raw consumption collected from butcher shops and retail stores in Turin’s province (Piedmont region, Northwest Italy). Twenty-five samples were examined in parallel by histology and polymerase chain reaction (PCR). The prevalence of infestation of Sarcocystis spp. resulted to be 64% [confidence interval (CI) 95% 42-82] and 88% (CI 95% 69-97) respectively by histology and PCR. In detail, the prevalence resulted 80% for S. cruzi (CI 95% 59-93), 68% for S. hominis (CI 95% 46-85) and 4% for S. hirsuta (CI 95% 0.10-20). The high prevalence of S. hominis highlights that sarcosporidiosis may constitute a public health problem in Italy, particularly in regions like Piedmont, that has traditional dishes prepared from raw or undercooked bovine meat.

First identification of Sarcocystis hominis in Iranian traditional hamburger

Zoonotic concerns of cattle sarcocystosis are of importance, because humans are the final host for Sarcocystis hominis. Therefore the meat products containing beef may encompass sarcocysts which endanger food safety. In this study, we described the first report of molecular identification of S. hominis in Iranian traditional hamburgers using PCR-RFLP. Throughout a pilot research that was carried out to setup a molecular approach to identify the Sarcocystis spp., using PCR-RFLP, a sample of raw Iranian traditional hamburger was purchased from a street food seller located in Yazd, central Iran in May 2013. DNA extraction was done, by salting out method; briefly, the sample was lysed with NET buffer. The DNA purification and precipitation was then performed. Amplicon and digestion results were analyzed, using gel agarose electrophoresis. The results showed a PCR product with 926 bp in length after amplification and 376 and 550 bp in length after digestion. This product was identified as S. hominis. To the best of our knowledge, this is the first report of S. hominis infection in Iranian hamburger.