Hemolytic Bacteria Research Articles

Investigating the resistome of haemolytic bacteria in Arctic soils.

Microorganisms inhabiting hostile Arctic environments express a variety of functional phenotypes, some of clinical interest, such as haemolytic ability and antimicrobial resistance. We studied haemolytic bacterial isolates from Arctic habitats, assessing their minimum inhibitory concentration (MIC) against antimicrobials. We then performed whole genome sequencing and analysed them for features conferring antimicrobial resistance. MIC data showed that Micromonospora spp. belong to 33% non-wild type (NWT) for erythromycin and penicillin and 22% NWT for tetracycline. Both Pseudomonas spp. belong to 43% NWT for nalidixic acid and streptomycin and 29% NWT for colistin. Finally, the Pedobacter isolate was in 80% NWT for antimicrobials tested. Whole-genome sequencing analyses revealed that fluoroquinolones, tetracyclines, macrolides and penams were the most frequent drug classes against which genotypic resistance was found. Additionally, resistance genes to heavy metals and disinfectants were identified. Our research demonstrates the presence of antimicrobial resistance in bacteria from Arctic habitats and highlights the importance of conservation efforts in these environments, where anthropogenic influence is becoming more evident. Furthermore, our data suggest the possible presence of novel resistance mechanisms, which could pose a threat if the responsible genes are transferable between species or become widespread due to environmental stress and alterations brought about by climate change.

Isolation and comparative analysis of culturable bacterial communities associated with life stages, breeding and rearing substrates of Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae) vector of bluetongue virus.

Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae) has been vectoring several arboviruses, protozoa and nematodes, leading to mortality and morbidity of livestock and wild ruminants in the tropics and subtropics. Insight into the bacterial communities associated with the vector species must be worked out. This work tries to inventorize the bacterial communities associated with this important vector species. Acquisition of gut microbiota may be the parental origin, while some are obtained through feeding during larval stages. Culicoides oxystoma possesses semi-aquatic life cycle strategies for egg-laying and larval survival. The bacteria associated with C. oxystoma were compared throughout (i) life stages: egg, larval instars, pupa, adult: male and female obtained from laboratory colony; (ii) field-collected adult: male and age-graded females; and (iii) natural breeding substrate and artificial rearing substrate. The culture-dependent bacteria were identified by Sanger sequencing of 16S rRNA, and haemolytic bacteria were screened on blood agar. Results show that Firmicutes and Proteobacteria are the predominant Phyla, of which Bacillus spp. was the most abundant across the life stages. Across the life history, Bacillus cereus, Bacillus pumilus, Bacillus tropicus, Lysinibacillus sp. and Paenibacillus sp. were retrieved routinely. Bacillus cereus and Alcaligenes faecalis were detected in the lab-reared specimens and shared between the natural breeding site and rearing medium. From the adults trapped across two locations, B. cereus, Bacillus flexus, A. faecalis, Enterococcus faecium and Pseudomonas sp. were isolated. The bacterial species associated with this vector may influence various physiological traits, such as vectorial capacity, digestion and larval development, which need further investigation.

Distribution and survival of pathogens from different waste components and bioaerosol traceability analysis in household garbage room

Household garbage rooms release abundant bioaerosols and are an important source of pathogens; however, information on the distribution and survival patterns of pathogens in different waste components is limited. In this study, a culture method and 16S rRNA high-throughput sequencing were used to determine bacterial communities, culturable pathogens, and human bacterial pathogens (HBPs). The results showed that abundant culturable bacteria were detected in all waste types, and a large number of S. aureus was detected on the surface of recyclable wastes, whereas S. aureus, total coliforms, Salmonella, Enterococcus, and hemolytic bacteria were detected in food waste and other waste. The activities of these detected pathogenic bacteria decreased after 24 h of storage but re-activated within one week. Factors affecting the emergence of pathogens varied with different waste components. Sequencing results showed that Pseudomonas, Acinetobacter, and Burkholderia were abundant in the waste samples, whereas Achromobacter, Exiguobacteriums, Bordetella, and Corynebacterium were the primary pathogens in the bioaerosol and wall attachment. The results of traceability analysis showed that bioaerosol microbes were mainly derived from raw kitchen waste (5.98%) and plastic and paper contaminated with food waste (19.93%) in garbage rooms. In addition, bioaerosols were the main source of microflora in the wall attachment, which possessed high HBP diversity and required more attention. These findings will help in understanding the microbial hazards in different waste components and provide guidance for the control and risk reduction of bioaerosols during waste management and recycling.

Evaluation of pathogen spread risk from excavated landfill

Landfill is a huge pathogen reservoir and needs special attention. Herein, the distribution and spread risk of pathogen were assessed in excavated landfill scenario. The results show that landfill excavation will greatly increase the risk of environmental microbial contamination. The highest total concentration of culturable bacteria among landfill refuse, topsoil and plant leaves was found to be as high as 1010 CFU g−1. Total coliforms, Hemolytic bacteria, Staphylococcus aureus, Salmonella, Enterococci, and Fecal coliforms were detected in the landfill surrounding environment. Notably, pathogens were more likely to adhere to plant leaves, making it an important source of secondary pathogens. The culturable bacteria concentration in the air samples differed with the landfill zone with different operation status, and the highest culturable bacteria concentration was found in the excavated area of the landfill (3.3 × 104 CFU m−3), which was the main source of bioaerosol release. The distribution of bioaerosols in the downwind outside of the landfill showed a tendency of increasing and then decreasing, and the highest concentration of bioaerosols outside of the landfill (6.56 × 104 CFU m−3) was significantly higher than that in the excavated area of the landfill. The risk of respiratory inhalation was the main pathway leading to infection, whereas the HQin (population inhalation hazardous quotient) at 500 m downwind the excavation landfill was still higher than 1, indicating that the neighboring residents were exposed to airborne microbial pollutants. The results of the study provide evidence for bioaerosols control protective measures taken to reduce health risk from the excavated landfill.

Diabetic Foot Ulcer on Coronavirus Patient

BACKGROUND: Corona virus (COVID 19) is an infection caused by a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The manifestation is from mild symptoms to severe symptoms such as respiratory failure and death. The severity of symptoms that arises in COVID-19 patients is influenced by the comorbidities they have. One of the comorbidities is diabetes. Increasing blood viscosity and severe inflammation occur in the body of COVID-19 patients. Meanwhile, problems such as coagulation factors, body blood flow, disorders of the nerves, lowering the immune response also occur in diabetic patients and etc. One of the complications of diabetes that often occurs is diabetic foot ulcers. The wound will be aggravated by a bacterial infection, such as hemolytic Streptococcus. Delay in diabetic ulcer treatment increases the incidence of amputation, sepsis and death. One of the therapies for diabetic foot ulcer is negative pressure wound therapy (NPWT). NPWT has a higher total cure rate, shorter healing time, and fewer amputations. If the wound is large, it can be continued with Split-Thickness skin graft (STSGs). CASE REPORT: A-54-year-old male patient, moderately confirmed COVID 19 with diabetes Mellitus comorbidty and diabetic foot ulcer. Around the wound there was a black tissue the base of which were muscles and tendons. The tissue culture examination found hemolytic streptococcus bacteria. Diabetic ulcers are given antibiotic therapy, NPWT and STSG. After the patient had been discharged from the hospital and then examined by the surgical clinic, the wound was closed completely. CONCLUSION: Diabetes is also a comorbid COVID-19 infection. Patients who are infected with COVID-19 and have uncontrolled blood sugar will prolong the treatment period for diabetic foot ulcers and can improve amputation therapy. Negative-Pressure Wound Therapy (NPWT) is a tool that is often and effective used for wound management.

Field trial: disinfection of contaminated anesthetic masks for piglets

This paper aimed to assess the success of cleaning and disinfection on microbiological contamination of anesthetic masks, which were used for automated isoflurane anesthesia for surgical castration of male piglets. Data collection took place on 11 farms in Southern Germany between September 2020 and June 2022. Each farm was visited three times (one farm having two different anesthesia devices was visited six times), and microbiological assessments took place at four sample points (SP): after unpacking the masks (SP0), after disinfection before anesthesia (SP1), after anesthesia of all piglets to be castrated in this run (SP2), and after disinfection after anesthesia (SP3). The microbiological assessment included the determination of total bacteria count, total count of hemolytic and non-hemolytic mesophilic aerotolerant bacteria and a qualitative detection of indicator bacteria Escherichia (E.) coli, extended-spectrum beta-lactamase-producing E. coli (ESBL) and methicillin-resistant Staphylococcus aureus (MRSA). For analysis, a generalized linear mixed model was applied using farms and farm visits as random effects and sampling points nested in farm visits as fixed effect. The fixed effect was highly significant for all three variables (total bacteria count, total count of hemolytic and non-hemolytic mesophilic aerotolerant bacteria) (p < 0.001). The bacterial counts at SP0 were about the same as at SP3. Concerning indicator bacteria, their presence was highest at SP2 and lowest at SP3. No indicator bacteria were present at SP1. It can be concluded that disinfection of anesthetic masks, especially before performing anesthesia, may effectively protect piglets of the following batch against unwanted transmission of pathogens. These findings will help farmers plan cleaning and disinfection activities.

In vitro biochemical characterization and identification of hemolytic bacteria associated with life history of Culicoides peregrinus (Diptera: Ceratopogonidae), a vector of bluetongue virus.

Gut bacterial communities in insects provide several beneficial roles like nutrition, digestion, fecundity, and survival of the host. The microbial communities of Culicoides spp. (Diptera: Ceratopogonidae) vary with parity, developmental stages, and environmental factors. Previous studies have revealed the presence of hemolytic bacteria in adult Culicoides peregrinus Kieffer (Diptera: Ceratopogonidae), an important vector of bluetongue virus (BTV). Our objectives were (i) to identify bacterial communities with hemolytic activities associated with all life stages and (ii) to compare between reared and field-collected adults including age graded females. Bacterial identification followed Sanger sequencing of 16S rRNA. In vitro biochemical characterizations including antibiotic sensitivity tests were also done. The majority of bacterial species were beta hemolytic with one, Alcaligenes faecalis, showing alpha hemolysis. Most bacterial species were observed in field-collected adults except Proteus spp. Throughout the life history of the vector, Bacillus cereus (CU6A, CU1E) and Paenibacillus sp. (CU9G) were detected indicating their possible role in blood digestion within the gut of this vector species. In vivo hemolytic activities of these culturable bacterial communities within this vector may be addressed in future. These hemolytic bacterial communities may be targeted to develop novel and effective strategies for vector control.

Assessment of Dust, Chemical, Microbiological Pollutions and Microclimatic Parameters of Indoor Air in Sports Facilities.

The aim of this study was to analyse the quality of indoor air in sport facilities in one of the sport centres in Poland with respect to microclimatic parameters (temperature, humidity, and air flow velocity), particulate matter concentrations (PM10, PM4, PM2.5, and PM1), gas concentrations (oxygen, ozone, hydrogen sulphide, sulphur dioxide, volatile organic compounds, and benzopyrene), and microbial contamination (the total number of bacteria, specifically staphylococci, including Staphylococcus aureus, haemolytic bacteria, Enterobacteriaceae, Pseudomonas fluorescens, actinomycetes, and the total number of fungi and xerophilic fungi). Measurements were made three times in May 2022 at 28 sampling points in 5 different sporting areas (the climbing wall, swimming pool, swimming pool changing room, and basketball and badminton courts) depending on the time of day (morning or afternoon) and on the outside building. The obtained results were compared with the standards for air quality in sports facilities. The air temperature (21−31 °C) was at the upper limit of thermal comfort, while the air humidity (RH < 40%) in the sports halls in most of the locations was below demanded values. The values for dust pollution in all rooms, except the swimming pool, exceeded the permissible limits, especially in the afternoons. Climatic conditions correlated with a high concentration of dust in the indoor air. Particulate matter concentrations of all fractions exceeded the WHO guidelines in all researched premises; the largest exceedances of standards occurred for PM2.5 (five-fold) and for PM10 (two-fold). There were no exceedances of gaseous pollutant concentrations in the air, except for benzopyrene, which resulted from the influence of the outside air. The total number of bacteria (5.1 × 101−2.0 × 104 CFU m−3) and fungi (3.0 × 101−3.75 × 102 CFU m−3) was exceeded in the changing room and the climbing wall hall. An increased number of staphylococci in the afternoon was associated with a large number of people training. The increased concentration of xerophilic fungi in the air correlated with the high dust content and low air humidity. Along with the increase in the number of users in the afternoon and their activities, the concentration of dust (several times) and microorganisms (1−2 log) in the air increased by several times and 1−2 log, respectively. The present study indicates which air quality parameters should be monitored and provides guidelines on how to increase the comfort of those who practice sports and work in sports facilities.

국내 수유부로부터 수집한 모유의 항산화 및 항용혈 효과

To confirm the antioxidant and anti-hemolytic activity in human breast milk (HBM), evaluated DPPH radical scavenging and anti-hemolytic activities against hemolytic strains. As a result of measuring the pH of HBM according to the days after childbirth, the pH of the HBM less than 10 days after childbirth was 6.63±0.26, the longer the lactation period, the lower the pH of breast milk. As a result of measuring the pH of HBM according to the days after childbirth, the pH of HBM less than 10 days after childbirth was 6.63±0.26 and over 30 days after childbirth was 6.45±0.15. These results indicated that the pH of HBM decreases as the days after childbirth increases. In contrast DPPH radical scavenging activity was the highest in HBM of over 30 days after childbirth (63.72±12.24%), that is presumed to be due to the fatty acid content in HBM. As a result of confirming hemolysis of HBM, weak hemolysis was observed in some HBM samples, that are caused to be hemolysis by bacteria produced the hemolysin in HBM. Therefore, result of analyzing the anti-hemolytic effect of HBM against the hemolytic bacteria, the effect of breast milk against the gram-positive S. aureus CCARM 3855 was 66.37±21.36%, gram-negative P. aeruginosa CCARM 0223 was 29.74±9.31%. In addition, HBM samples of the less than 10 days after childbirth showed highest each anti-hemolytic activity against hemolytic strain. Thus, this study can be suggested that it will be basic study for preventing hemolytic disease in newborns.

The Influence of Commercial Feed Supplemented with Carnobacterium maltaromaticum Environmental Probiotic Bacteria on the Rearing Parameters and Microbial Safety of Juvenile Rainbow Trout.

The aim of this study was to determine the effect of commercial feed (CF) supplemented with 0.1% of the Carnobacterium maltaromaticum environmental probiotic strain on the rearing parameters, apparent nutrient digestibility, and microbial safety of juvenile rainbow trout (Oncorhynchus mykiss). The fish were fed CF (control group, CG) and experimental feed (EF) supplemented with 0.1% of C. maltaromaticum (experimental group, EG) for 56 days. The final body weight and total body length of the fish were measured. The growth rate, condition factor, feed conversion ratio, viscerosomatic and hepatosomatic indices, and apparent digestibility coefficients of protein (PAD), lipids (LAD), ash (AAD), and nitrogen-free extract (NFEAD) were calculated. The total viable counts of C. maltaromaticum bacteria, mesophilic bacteria, hemolytic mesophilic bacteria, Pseudomonas fluorescens, Aeromonas hydrophila, Staphylococcus sp., and sulfite-reducing anaerobic spore-forming Clostridium sp. were determined in digestive tract contents and the skin of fish. Feed supplementation with C. maltaromaticum significantly affected most rearing parameters, as well as the PAD, LAD, AAD and NFE values, and bacterial counts. The principal component analysis (PCA) revealed significant positive correlations (p < 0.05) between fish growth rates, PAD and LAD values vs. C. maltaromaticum counts in the EF and in the digestive tract contents of the fish.

Phenotypic characteristic of Staphylococcus aureus from subclinical mastitis in Etawah-crossbreed goats in Yogyakarta, Indonesia.

Subclinical mastitis (SCM) in Etawah-grade (PE) goats in Yogyakarta, Indonesia, is commonly due to Staphylococcus aureus. At present, S. aureus from SCM in PE goats in Yogyakarta has not been characterized. Therefore, this study aimed to phenotypically characterize S. aureus, which has been isolated from SCM of PE goats. A total of 314 lactating PE goats were collected from 60 PE goat farms (e.g., Sleman, Bantul, and Kulonprogo) located in parts of Yogyakarta with an average age of 3-4 years old, three of which showed SCM based on the California mastitis test (CMT). Subclinical mastitis is confirmed in PE goats if CMT shows ++ or +++. Furthermore, S. aureus was detected by biochemical assays. Staphylococcus aureus could determine hemolysin (Hae), coagulase (Coa), clumping factor (Cf), and antibiotic susceptibility. Hemolytic bacteria were detected by culturing on blood agar plate, and Cf was detected by slide agglutination. The production of Coa was detected by tube coagulation. Staphylococcus aureus susceptibility was determined by antimicrobial agar diffusion using a paper disc. Phenotypically characterized S. aureus from PE goats with SCM in Yogyakarta, Indonesia, Coa-, Cf-, and Hae- were found to be resistant to erythromycin (ERYTHRO), ampicillin (AMP), penicillin (PEN-G), and sulfamethoxazole (SULFA). The phenotypic characteristic of S. aureus, which was obtained from SCM in PE goats in Yogyakarta, consists of Coa, and Cf-. S. aureus cannot perform hemolysis of red blood cells. This phenotypic characteristic can prevent and control SCM in PE goats. Several antibiotics such as ERYTHRO, AMP, PEN-G, and SULFA were no longer effective for treating SCM in PE goats because S. aureus has developed its resistance to these antibiotics.

Detection of Streptokinase Production by Streptococcus pyogen using Real Time PCR

Tonsillitis which is commonly referred to a strep throat is caused by group A β-hemolytic streptococci (GABHS) or Streptococcus pyogenes. The bacteria is consider as one of the major human-specific bacterial pathogen and one of its virulence factors is the streptokinase; for this reason, 100 tonsillitis swabs were taken from Iraqi children suffering from symptoms of sore throat. Using conventional cultural methods, 60 bacterial isolates were characterized and subjected to biochemical tests. As a result, 40 isolates were identified as hemolytic bacteria and only 6 of them were identified as Streptococcus. pyogens using Bacitracin (0.04) and Vitek 2 system. The ability of the 6 isolates for streptokinase production was screened and the results showed that all of them were produce the enzyme with variable degrees. Molecular detection of streptokinase gene using real time PCR technique has been done with specific primers and the amplification results were present with all S.pyogens strains.

Identification of PST 10 bacterial isolate with ?-hemolysis characteristic isolated from pig's tonsil

Background: Pig's tonsil is one of the entry points and habitat of commensal microbes and pathogenic bacteria, both Gram-positive and Gram-negative bacteria. Recently, a human meningitis outbreak has reported at Sibang Kaja, Badung-Bali. The cause of this outbreak has been suspected due to the consumption of pig-derived foods. The outbreak was known to be caused by Gram-positive ?-hemolytic bacteria. Based on this fact, PST 10 bacterial isolate with similar characteristics to the outbreak caused interesting identification.Method: PST 10 isolate was cultivated in a specific medium 5% defibrinated sheep blood agar plate. Subsequently, Gram staining, catalase, oxidase, salt tolerance (6% NaCl), and hemolysis test. This presumptive isolation was then conventionally identified by KIT API 20 STREP and molecularly using the 16S rRNA gene.Results: PST 10 isolate was identified as Enterococcus faecium using KIT API 20 STREP. Furthermore, the 16S rRNA gene sequencing analysis shows that the isolate has 99.6% similarities with Enterococcus faecalis (MG543832). The isolate shares the same clade in the phylogenetic tree analysis with a 100% bootstrap value.Conclusion: The high sensitivity in molecular identification mainly to distinguish close species using phenotypic approaches, PST 10 isolate was concluded as Enterococcus faecalis.

Fever temperatures impair hemolysis caused by strains of Escherichia coli and Staphylococcus aureus

Hemolysis modulates susceptibility to bacterial infections and predicts poor sepsis outcome. Hemolytic bacteria use hemolysins to induce erythrocyte lysis and obtain the heme that is essential for bacterial growth. Hemolysins are however potent immunogens and infections with hemolytic bacteria may cause a reversible fever response from the host that will aid in pathogen clearance. We hypothesized that fever temperatures impact the growth and infectivity of two hemolytic bacteria that are known to evoke fever in patients. To that end, we used high-sensitivity microcalorimetry to measure the evolution of heat production in fever-inducing strains of Escherichia coli and Staphylococcus aureus, under different temperature conditions. We determined specific bacterial aggregation profiles at temperatures equal to or exceeding 38.5 °C. Two melting temperatures peaks ranged from 38 °C to 43 °C for either species, a feature that we assigned to the formation of hemolysin aggregates of different oligomerization order. In order to measure the role of fever temperatures on hemolysis, we incubated the pathogens on blood agar plates at relevant temperatures, measuring the presence of hemolysis at 37 °C and its absence at 40.5 °C, respectively. We conclude that fever temperatures affect the kinetics of hemolysin pore formation and subsequently the hemolysis of red blood cells in vitro. We reveal the potential of microcalorimetry to monitor heat response from fever inducing bacterial species. Furthermore, these results help establish an additional positive role of febrile temperatures in modulating the immune response to infections, through the abolishment of hemolysis.

Genome placement of alpha-haemolysin cluster is associated with alpha-haemolysin sequence variation, adhesin and iron acquisition factor profile of Escherichia coli.

Since the discovery of haemolysis, many studies focused on a deeper understanding of this phenotype in Escherichia coli and its association with other virulence genes, diseases and pathogenic attributes/functions in the host. Our virulence-associated factor profiling and genome-wide association analysis of genomes of haemolytic and nonhaemolytic E. coli unveiled high prevalence of adhesins, iron acquisition genes and toxins in haemolytic bacteria. In the case of fimbriae with high prevalence, we analysed sequence variation of FimH, EcpD and CsgA, and showed that different adhesin variants were present in the analysed groups, indicating altered adhesive capabilities of haemolytic and nonhaemolytic E. coli . Analysis of over 1000 haemolytic E. coli genomes revealed that they are pathotypically, genetically and antigenically diverse, but their adhesin and iron acquisition repertoire is associated with genome placement of hlyCABD cluster. Haemolytic E. coli with chromosome-encoded alpha-haemolysin had high frequency of P, S, Auf fimbriae and multiple iron acquisition systems such as aerobactin, yersiniabactin, salmochelin, Fec, Sit, Bfd and hemin uptake systems. Haemolytic E. coli with plasmid-encoded alpha-haemolysin had similar adhesin profile to nonpathogenic E. coli, with high prevalence of Stg, Yra, Ygi, Ycb, Ybg, Ycf, Sfm, F9 fimbriae, Paa, Lda, intimin and type 3 secretion system encoding genes. Analysis of HlyCABD sequence variation revealed presence of variants associated with genome placement and pathotype.

Weissella confusa with thermostable β-hemolytic exopolysaccharide

Consuming cooked meat contaminated with bacteria that carry thermostable hemolytic exopolysaccharide (ESP), could lead to severe diseases. Culture of a 5- h boiled sample of meat goulash on blood agar showed growth of a gram positive rod-shaped, mucoid and hemolytic bacterium. Biochemical tests and amplification of 1500 bp product of 16S rDNA and sequencing revealed bacterial identity as Weissella confusa. After 1 h boiling of bacterial suspension, they were alive and hemolytic, increased in volume and aggregated. After 8 h boiling of bacterial suspension with coverslip, live bacteria showed hemolysis, clustered and adhered to coverslip. Bacterial bacteriocin and hemolytic activities remained unchanged upon autoclaving. Purified bacterial EPS retained hemolytic activity after autoclaving. Boiling contaminated meat had no negative impact on viability of heat-stable W. confusa and its hemolytic EPS. Thermostable hemolytic EPS protected W. confusa from excessive heat. Hygienic practice in butcheries and kitchens are necessary to eliminate bacterial contaminants.

Bioplastic accumulates antibiotic and metal resistance genes in coastal marine sediments

The oceans are increasingly polluted with plastic debris, and several studies have implicated plastic as a reservoir for antibiotic resistance genes and a potential vector for antibiotic-resistant bacteria. Bioplastic is widely regarded as an environmentally friendly replacement to conventional petroleum-based plastic, but the effects of bioplastic pollution on marine environments remain largely unknown. Here, we present the first evidence that bioplastic accumulates antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) in marine sediments. Biofilms fouling ceramic, polyethylene terephthalate (PET), and polyhydroxyalkanoate (PHA) were investigated by shotgun metagenomic sequencing. Four ARG groups were more abundant in PHA: trimethoprim resistance (TMP), multidrug resistance (MDR), macrolide-lincosamide-streptogramin resistance (MLS), and polymyxin resistance (PMR). One MRG group was more abundant in PHA: multimetal resistance (MMR). The relative abundance of ARGs and MRGs were strongly correlated based on a Mantel test between the Bray-Curtis dissimilarity matrices (R = 0.97, p < 0.05) and a Pearson's analysis (R = 0.96, p < 0.05). ARGs were detected in more than 40% of the 57 metagenome-assembled genomes (MAGs) while MRGs were detected in more than 90% of the MAGs. Further investigation (e.g., culturing, genome sequencing, antibiotic susceptibility testing) revealed that PHA biofilms were colonized by hemolytic Bacillus cereus group bacteria that were resistant to beta-lactams, vancomycin, and bacitracin. Taken together, our findings indicate that bioplastic, like conventional petroleum-based plastic, is a reservoir for resistance genes and a potential vector for antibiotic-resistant bacteria in coastal marine sediments.

Gemella haemolysans inhibits the growth of the periodontal pathogen Porphyromonas gingivalis

The oral microbiome plays an important role in the human microbial community and in maintaining the health of an individual. Imbalances in the oral microbiome may contribute to oral and systemic diseases. The progression of periodontal disease is closely related to the growth of bacteria, such as Porphyromonas gingivalis, in the oral cavity. However, the pathogen growth mechanism specific to periodontal disease remains unknown. This study aimed to identify bacteria associated with periodontal health by focusing on hemolytic bacteria. Unstimulated saliva samples were collected from ten periodontitis patients and five healthy subjects to detect and identify the presence of hemolytic bacteria. The saliva of healthy subjects contained a higher proportion of G. haemolysans than saliva samples from patients with periodontitis. Growth inhibition assays indicated that the protein components contained in the culture supernatant of G. haemolysans directly suppressed the growth of P. gingivalis. This study shows that the presence of G. haemolysans in saliva is associated with periodontal health and that it inhibits the growth of P. gingivalis in vitro.

Prevalence of Group B Streptococcus in Vagina and Rectum of Pregnant Women of Islamic & Non-Islamic Countries: A Systematic Review and Meta-Analysis.

Background:Group B streptococcus or streptococcus Agalactia is a gram positive beta hemolytic bacteria which is the main factor in neonatal infections. This study aimed at determining the prevalence of GBS in world and clarifying the rate of this infection in Islamic and non-Islamic countries.Methods:We performed a systematic search by using different databases including Medline, Scopus, Science Direct, Psycho-Info ProQuest and Web of Science published up to Feb 2019. We undertook meta-analysis to obtain the pooled estimate of prevalence of GBS colonization in Islamic and non-Islamic countries.Results:Among 3324 papers searched, we identified 245 full texts of prevalence of GBS in pregnancy; 131 were included in final analysis. The estimated mean prevalence of maternal GBS colonization was 15.5% (CI:95% (14.2–17)) worldwide; which was 14% (CI:95% (11–16.8)) in Islamic and 16.3% (CI:95% (14.6–18.1)) in non-Islamic countries and was statistically significant. Moreover, with regards to sampling area, prevalence of GBS colonization was 11.1 in vagina and 18.1 in vagina-rectum.Conclusion:Frequent washing of perineum based on religious instructions in Islamic countries can diminish the rate of GBS colonization in pregnant women.

Heme controls the structural rearrangement of its sensor protein mediating the hemolytic bacterial survival

Hemes (iron-porphyrins) are critical for biological processes in all organisms. Hemolytic bacteria survive by acquiring b-type heme from hemoglobin in red blood cells from their animal hosts. These bacteria avoid the cytotoxicity of excess heme during hemolysis by expressing heme-responsive sensor proteins that act as transcriptional factors to regulate the heme efflux system in response to the cellular heme concentration. Here, the underlying regulatory mechanisms were investigated using crystallographic, spectroscopic, and biochemical studies to understand the structural basis of the heme-responsive sensor protein PefR from Streptococcus agalactiae, a causative agent of neonatal life-threatening infections. Structural comparison of heme-free PefR, its complex with a target DNA, and heme-bound PefR revealed that unique heme coordination controls a >20 Å structural rearrangement of the DNA binding domains to dissociate PefR from the target DNA. We also found heme-bound PefR stably binds exogenous ligands, including carbon monoxide, a by-product of the heme degradation reaction.