Detection of virulence genes of Staphylococcus aureus isolated from raw beef for retail sale in the markets of Ulaanbaatar city, Mongolia

BACKGROUND

Staphylococcus aureus (S. aureus) is a highly virulent pathogen that causes food-borne illness, food poisoning, skin and soft tissue infections, abscesses, mastitis, and bacteremia. It is common for meat and meat products to become contaminated with S. aureus due to dirty hands, food storage conditions, food production processes, and unhygienic conditions, causing food poisoning. Therefore, we aimed to isolate S. aureus strain from the raw beef and reveal virulence genes and antibiotic resistance profile from isolated S. aureus strains.

METHODS

In this study, 100 samples of raw beef were collected from 4 major market stalls in Ulaanbaatar city, Mongolia. S. aureus was detected according to the ISO 6888-1:2021 standard, and the nucA gene encoding the species-specific thermonuclease was amplified and confirmed by polymerase chain reaction (PCR). In the strains of S. aureus isolated from the samples, the genes encoding the virulence factors including sea, sed, tsst, eta, etb, and mecA were amplified by multiplex PCR. These genes are encoded staphylococcal enterotoxin A, enterotoxin D, toxic shock syndrome toxin, exotoxin A, exotoxin B and penicillin-binding protein PBP 2A, respectively. Antibiotic sensitivity test was performed by the Kirby-Bauer disc diffusion method. The Clinical and Laboratory Standard Institute guidelines as CLSI M100-S27 was used for analysis of the data.

RESULTS

Thirty-five percent of our samples were detected contaminated with of the S. aureus strains. Subsequently, antibiotic resistance was observed in the S. aureus contaminated samples. Among our samples, the highest rates of resistance were determined against ampicillin (97.1%), oxacillin (88.6%), and penicillin (88.6%), respectively. Three genes including mecA, sea, and tsst from six virulence genes were detected in 17% of S. aureus strain-contaminated samples by multiplex PCR. The sed, etb and eta genes were detected in the 2.9%, 11.4% and 5.7% of our samples, respectively.

CONCLUSION

The results show that S. aureus related contamination is high in the raw beef for retail sale and prevalent S. aureus strains are resistant to all antibiotics used. Also, our results have demonstrated that there is a high risk for food poisoning caused by antibiotic resistant S. aureus in the raw beef and it may establish public health issues. Genes encoding for both heat-resistant and nonresistant toxicity factors were detected in the antibiotic resistant S. aureus strains and shown the highly pathogenic. Finally, our study is ensuring to need proper hygienic conditions during beef's preparation and sale.

Deaths related to drowning in Antalya, an important tourism center in the Mediterranean region: A 10-year retrospective study

Objectives: Drowning is one of the most common causes of accidental deaths in all age groups. This study aims to compare the sociodemographic data, scene of incident findings, clinical characteristics, and autopsy findings of Turkish and foreign victims of drowning in Antalya, one of the most popular global holiday destinations. Study Design: This study is the most extensive case series of drowning in Turkey. Methods: A retrospective examination was made of 7775 autopsies, of which 692 (8.9%) were identified as drowning cases. Results: Almost half of the cases were elderly males of foreign nationality, with a chronic disease and high alcohol consumption, who were found wearing swimming clothes and had died accidentally, mostly in the sea or swimming pools. The majority of Turkish victims were male children and adolescents, found wearing normal daily clothes, who died from a fall or while performing high-risk activities, such as jumping from height. Most of these cases died at the scene of the incident due to an accident or suicide. Conclusions: Such incidences of deaths in Antalya could be reduced with the implementation of precautions, with adjustments made according to the increased risks and, particularly, the mobility of the older age group. Significantly, chronic disease is an important risk factor in cases of drowning.

Staphylococcus aureus biofilm properties and chronic rhinosinusitis severity scores correlate positively with total CD4+ T-cell frequencies and inversely with its Th1, Th17 and regulatory cell frequencies

Chronic rhinosinusitis (CRS) represents chronic inflammation of the sinus mucosa characterised by dysfunction of the sinuses' natural defence mechanisms and induction of different inflammatory pathways ranging from a Th1 to a Th2 predominant polarisation. Recalcitrant CRS is associated with Staphylococcus aureus dominant mucosal biofilms; however, S. aureus colonisation of the sinonasal mucosa has also been observed in healthy individuals challenging the significance of S. aureus in CRS pathogenesis. We aimed to investigate the relationship between CRS key inflammatory markers, S. aureus biofilm properties/virulence genes and the severity of the disease. Tissue samples were collected during endoscopic sinus surgery from the ethmoid sinuses of CRS patients with (CRSwNP) and without (CRSsNP) nasal polyps and controls (n = 59). CD3+ T-cell subset frequencies and key inflammatory markers of CD4+ helper T cells were determined using FACS analysis. Sinonasal S. aureus clinical isolates were isolated (n = 26), sequenced and grown into biofilm in vitro, followed by determining their properties, including metabolic activity, biomass, colony-forming units and exoprotein production. Disease severity was assessed using Lund-Mackay radiologic scores, Lund-Kennedy endoscopic scores and SNOT22 quality of life scores. Our results showed that S. aureus biofilm properties and CRS severity scores correlated positively with total CD4+ T-cell frequencies but looking into CD4+ T-cell subsets showed an inverse correlation with Th1 and Th17 cell frequencies. CD4+ T-cell frequencies were higher in patients harbouring lukF.PV-positive S. aureus while its regulatory and Th17 cell subset frequencies were lower in patients carrying sea- and sarT/U-positive S. aureus. Recalcitrant CRS is characterised by increased S. aureus biofilm properties in relation to increased total CD4+ helper T-cell frequencies and reduced frequencies of its Th1, Th17 and regulatory T-cell subsets. These findings offer insights into the pathophysiology of CRS and could lead to the development of more targeted therapies.

Mass casualty incidents during the ten years of telemedical maritime assistance service in Gdynia, Poland

Mass casualty incident (MCI) is one of the most difficult situation in emergency medicine. Due to the specific conditions, MCIs occurring at sea are usually far more demanding than those happening on land. In this paper the authors would like to describe the MCIs, which have happened during almost 10 years of functioning of the Polish Telemedical Maritime Assistance Service (TMAS). First incident concerned a group of migrants floating on a raft on the Gulf of Mexico. The cause of the second incident was acute organophosphate intoxication among the crew of the merchant ship. The third incident was triggered by the coronavirus disease 2019 (COVID-19). It is important to emphasize, that triage system may help in proper management of MCIs. Cooperation of the medical services, such as TMAS, local emergency medical staff, Search and Rescue (SAR) service and military force seems to be crucial in MCI managements occuring at sea. In case of any doubts, change of a course and heading to the nearest port or immediate evacuation should be taken into consideration. The authors believe that analysis of these incidents may help TMAS personnel all over the world to handle MCIs in the future. Med Pr. 2023;74(2).

Spinal Fractures during Touristic Motorboat Sea Cruises: An Underestimated and Avoidable Phenomenon

PURPOSE

Each summer, many vacationers enjoy the Mediterranean Sea shores. Among the recreational nautical activities, motorboat cruise is a popular choice that leads to a significant number of thoracolumbar spine fractures at our clinic. This phenomenon seems to be underreported, and its injury mechanism remains unclear. Here, we aim to describe the fracture pattern and propose a possible mechanism of injury.

METHODS

We retrospectively reviewed the clinical, radiological, and contextual parameters of all motorboat-related spinal fracture cases during a 14-year period (2006-2020) in three French neurosurgical level I centers bordering the Mediterranean Sea. Fractures were classified according to the AOSpine thoracolumbar classification system.

RESULTS

A total of 79 patients presented 90 fractures altogether. Women presented more commonly than men (61/18). Most of the lesions occurred at the thoracolumbar transition region between T10 and L2 (88.9% of the levels fractured). Compression A type fractures were seen in all cases (100%). Only one case of posterior spinal element injury was observed. The occurrence of neurological deficit was rare (7.6%). The most commonly encountered context was a patient sitting at the boat's bow, without anticipating the trauma, when the ship's bow suddenly elevated while crossing another wave, resulting in a "deck-slap" mechanism hitting and propelling the patient in the air.

CONCLUSIONS

Thoracolumbar compression fractures are a frequent finding in nautical tourism. Passengers seated at the boat's bow are the typical victims. Some specific biomechanical patterns are involved with the boat's deck suddenly elevating across the waves. More data with biomechanical studies are necessary to understand the phenomenon. Prevention and safety recommendations should be given before motorboat use to fight against these avoidable fractures.

A Drifter-Based Self-Powered Piezoelectric Sensor for Ocean Wave Measurements

Recently, piezoelectric materials have received remarkable attention in marine applications for energy harvesting from the ocean, which is a harsh environment with powerful and impactful waves and currents. However, to the best of the authors' knowledge, although there are various designs of piezoelectric energy harvesters for marine applications, piezoelectric materials have not been employed for sensory and measurement applications in marine environment. In the present research, a drifter-based piezoelectric sensor is proposed to measure ocean waves' height and period. To analyze the motion principle and the working performance of the proposed drifter-based piezoelectric sensor, a dynamic model was developed. The developed dynamic model investigated the system's response to an input of ocean waves and provides design insights into the geometrical and material parameters. Next, finite element analysis (FEA) simulations using the commercial software COMSOL-Multiphysics were carried out with the help of a coupled physics analysis of Solid Mechanics and Electrostatics Modules to achieve the output voltages. An experimental prototype was fabricated and tested to validate the results of the dynamic model and the FEA simulation. A slider-crank mechanism was used to mimic ocean waves throughout the experiment, and the results showed a close match between the proposed dynamic modeling, FEA simulations, and experimental testing. In the end, a short discussion is devoted to interpreting the output results, comparing the results of the simulations with those of the experimental testing, sensor's resolution, and the self-powering functionality of the proposed drifter-based piezoelectric sensor.

Blood pressure adaptation in vertebrates: Comparative biology

With evolution from water to land, the osmotic regulation of body fluids and cardiovascular systems of vertebrates evolved to cope with dryness and gravity. While aquatic vertebrates can use buoyancy to compensate for the effects of gravity, terrestrial vertebrates cannot, and must circulate blood throughout their body - a necessity that likely led to the development of strong hearts and high blood pressure. These changes may be supported by anatomical evolution of the cardiovascular system and by functional evolution, with alterations in hormonal systems. Thus, during the evolution of terrestrial animals, increased performance of body functions to endure harsher environments was required, necessitating increased blood pressure. In an age of overeating and insufficient exercise, modern man does not fully utilize the high levels of physical functions acquired through evolution. Drastic changes in our living environment cause hypertension, the pathogenesis of which remains unknown. To survive in new environments, as might be expected in outer space or underwater, an understanding is required of how changes in blood pressure have occurred that enabled adaptation through evolution in vertebrates.

[Research on Sealing Performance of One Way Valve of Thoracic Drainage Device]

For one-off water seal of components "one-way" chest drainage device in the actual process of using the sealing function of accidental failure problem, with the component design and processing quality, the rationality of the related production technology as a research object, through to the device internal sealing surface and processing quality, one-way valve floating switch, seal diaphragm installation effect, the weight of the components of clean degree and so on has carried on the experiment and analysis, find out the chest drainage of water sealing device of the main causes of the one-way valve seal failure in, and sum up the corresponding improving methods according to the results of the experiments, and improve the one-way valve sealing performance.

Passive Samplers, a Powerful Tool to Detect Viruses and Bacteria in Marine Coastal Areas

The detection of viruses and bacteria which can pose a threat either to shellfish health or shellfish consumers remains difficult. The current detection methods rely on point sampling of water, a method that gives a snapshot of the microorganisms present at the time of sampling. In order to obtain better representativeness of the presence of these microorganisms over time, we have developed passive sampling using the adsorption capacities of polymer membranes. Our objectives here were to assess the feasibility of this methodology for field detection. Different types of membrane were deployed in coastal waters over 2 years and the microorganisms tested using qPCR were: human norovirus (NoV) genogroups (G)I and II, sapovirus, Vibrio spp. and the species Vibrio alginolyticus, V. cholerae, V. vulnificus, and V. parahaemolyticus, OsHV-1 virus, and bacterial markers of fecal contamination. NoV GII, Vibrio spp., and the AllBac general Bacteroidales marker were quantified on the three types of membrane. NoV GII and OsHV-1 viruses followed a seasonal distribution. All membranes were favorable for NoV GII detection, while Zetapor was more adapted for OsHV-1 detection. Nylon was more adapted for detection of Vibrio spp. and the AllBac marker. The quantities of NoV GII, AllBac, and Vibrio spp. recovered on membranes increased with the duration of exposure. This first application of passive sampling in seawater is particularly promising in terms of an early warning system for the prevention of contamination in oyster farming areas and to improve our knowledge on the timing and frequency of disease occurence.

Marine Pharmacology in 2016-2017: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

The review of the 2016-2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016-2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016-2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories.

Passive Samplers, a Powerful Tool to Detect Viruses and Bacteria in Marine Coastal Areas

The detection of viruses and bacteria which can pose a threat either to shellfish health or shellfish consumers remains difficult. The current detection methods rely on point sampling of water, a method that gives a snapshot of the microorganisms present at the time of sampling. In order to obtain better representativeness of the presence of these microorganisms over time, we have developed passive sampling using the adsorption capacities of polymer membranes. Our objectives here were to assess the feasibility of this methodology for field detection. Different types of membrane were deployed in coastal waters over 2 years and the microorganisms tested using qPCR were: human norovirus (NoV) genogroups (G)I and II, sapovirus, Vibrio spp. and the species Vibrio alginolyticus, V. cholerae, V. vulnificus, and V. parahaemolyticus, OsHV-1 virus, and bacterial markers of fecal contamination. NoV GII, Vibrio spp., and the AllBac general Bacteroidales marker were quantified on the three types of membrane. NoV GII and OsHV-1 viruses followed a seasonal distribution. All membranes were favorable for NoV GII detection, while Zetapor was more adapted for OsHV-1 detection. Nylon was more adapted for detection of Vibrio spp. and the AllBac marker. The quantities of NoV GII, AllBac, and Vibrio spp. recovered on membranes increased with the duration of exposure. This first application of passive sampling in seawater is particularly promising in terms of an early warning system for the prevention of contamination in oyster farming areas and to improve our knowledge on the timing and frequency of disease occurence.

An evolutionary perspective on marine invasions

Species distributions are rapidly changing as human globalization increasingly moves organisms to novel environments. In marine systems, species introductions are the result of a number of anthropogenic mechanisms, notably shipping, aquaculture/mariculture, the pet and bait trades, and the creation of canals. Marine invasions are a global threat to human and non-human populations alike and are often listed as one of the top conservation concerns worldwide, having ecological, evolutionary, and social ramifications. Evolutionary investigations of marine invasions can provide crucial insight into an introduced species' potential impacts in its new range, including: physiological adaptation and behavioral changes to exploit new environments; changes in resident populations, community interactions, and ecosystems; and severe reductions in genetic diversity that may limit evolutionary potential in the introduced range. This special issue focuses on current research advances in the evolutionary biology of marine invasions and can be broadly classified into a few major avenues of research: the evolutionary history of invasive populations, post-invasion reproductive changes, and the role of evolution in parasite introductions. Together, they demonstrate the value of investigating marine invasions from an evolutionary perspective, with benefits to both fundamental and applied evolutionary biology at local and broad scales.

Health status of a sample of Beninese seafarers examined on the occasion of medical fitness for work at sea

BACKGROUND

In view of the considerable risks involved in maritime work, the medical fitness of seafarers is of paramount importance. A study carried out in May 2018 in Benin made it possible to describe the health profile of seafarers who received a medical examination before boarding and to identify the diseases likely to hinder their medical aptitude for this profession.

MATERIALS AND METHODS

This is a retrospective cross-sectional study that was based on 125 medical files registered from 2013 to 2017 and selected on the basis of the criteria of completeness, readability and non-overload of the entries.

RESULTS

The results showed that more than half (63.2%) of the seafarers in our series are over 40 years old. The prevalence of high blood pressure was 28.4% in the seafarer population. Obesity was detected in 21.5% of subjects. Of the moderate cases of hearing loss found, 4 out of 5 worked at the machine station. The unrestricted fitness level was 86.4%. One (0.8%) case of physical restriction and 12.8% of cases of mandatory wearing of medical glasses at work were reported. The "healthy worker effect" may underestimate the risk of marine activity to the health of seafarers when referring to the general population.

CONCLUSIONS

The study provides opportunities to improve the seafarers' health situation in accordance with international provisions such as the Maritime Labour Convention, 2006 (MLC, 2006) ratified by Benin in June 2011.

The speedboat vertebral fracture: a hazard of holiday watersports

PURPOSE

The purpose of this study was to describe and characterise spinal fractures sustained by watercraft occupants due to splashdown of light watercraft when riding over uneven water surfaces.

METHODS

A retrospective review of all patients presenting with these injuries to St Luke's and Mater Dei state hospitals in Malta over a 10-year period was undertaken to determine patient demographics, the nature of spinal injuries sustained and the incidence of any associated extra-spinal injuries.

RESULTS

Twenty-one patients (mean age 41.2 years) suffered 25 fractures. Injuries were seasonal, occurring exclusively between the months of May and October. One patient was local whilst 20 were from other countries. All fractures were Magerl type A fractures and occurred around the thoracolumbar junction. The L1 vertebra was most commonly affected (12 patients). Four patients sustained two vertebral fractures. There were no extra-spinal injuries.

CONCLUSIONS

Watercraft splashdown can transmit significant forces to occupants, resulting in Magerl type A vertebral fractures around the thoracolumbar junction. These injuries occur under compression. They are highly consistent in their morphology and localisation and should be excluded in individuals complaining of back pain after watercraft use. Almost all patients were from outside Malta and injuries were seasonal, providing opportunities for targeted injury prevention campaigns.

Experimental Study of LoRa Transmission over Seawater

Low Power Wide Area Networks (LPWANs) are gaining attention in both academia and industry by offering the possibility of connecting a large number of nodes over extended distances. LoRa is one of the technologies used as a physical layer in such networks. This paper investigates the LoRa links over seawater in two typical scenarios: clear Line-of-Sight (LOS) and obstructed path in two different Industrial, Scientific and Medical (ISM) radio bands: 868 MHz and 434 MHz. We used three different LoRa devices in the experiments: the Own Developed LoRa Transceiver (ODT) and two commercial transceivers. Firstly we investigated transceivers' Receive Signal Strength Indicator (RSSI) and Signal-to-Noise (SNR) measurement chain linearity and provided correction factors for RSSI to correlate it with actual signal levels received at transceivers' inputs. Next, we carried out field experiments for three different LoRa Spreading Factors, S F ∈ [ 7 , 10 , 12 ] , within a bandwidth of B W = 125 kHz and Coding Rate C R = 4 / 6 . The experiments showed that LoRa links are fully feasible over seawater at distances at least 22 km long, using only low-cost off-the-shelf rubber duck antennas in LOS path condition in both ISM bands. In addition, we showed that LoRa links can be established over 28 km obstructed LOS oversea path in ISM 434 MHz band, but using costly, higher gain antennas. Furthermore, the laboratory experiments revealed that RSSI is linear in a wide range, up to - 50 dBm, whereas the SNR measurement chain goes into saturation for Received Signal Strength (RSS) values higher than - 100 dBm. These findings enabled accurate interpretation of the results obtained in field experiments.

[The nurse in the organisation of medical assistance on board a ship]

Nursing practice on a ship involves certain risks and constraints inherent to the facilities themselves and the maritime environment. The response in the case of a medical incident at sea is guided by an organisation adapted to these constraints, overseen by a specific regulatory body. Different entities, players and resources may be involved depending on the diverse situations encountered.

Suicides by drowning in Greece: Findings from a 10-year sample (2006-2015)

We studied a sample of suicide victims from Greece's main port of Piraeus area (population: approx. 700,000 individuals) and investigated all suicides for the 10-year period 2006-2015, collecting data from the victims' forensic records at the Piraeus Department of Forensic Medicine. Sixty-nine (15.9%) out of 435 suicides were due to drowning, 51 (73.9%) males and 18 (26.1%) females. Drowning was the third most common suicide method with most in the sea (92.8%), fewer in wells (7.2%). Median age: males 52.2 years (standard deviation (SD): 20.3, range: 27-89) and females 58.8 years (SD: 15.2, range: 32-84). Psychiatric medications: antidepressants (6 cases, 8.9%), benzodiazepines (6 cases, 8.9%) and antipsychotics (1 case, 1.5%). Other substances: alcohol (14 cases, 20.9%), cocaine (1 case, 1.5%) and opioids (1 case, 1.5%). No seasonal effect was observed for suicides by drowning. Greece, being a country with an embracing coastline, could provide a field of study for suicide by drowning.

Epidemiology of unintentional drowning in a metropolis of the French Mediterranean coast: a retrospective analysis (2000-2011)

Drowning affects more than 500,000 people worldwide and is responsible for at least 350,000 deaths each year. In France, 1235 drowning resulting in 496 deaths were recorded in the summer 2012. This retrospective study has investigated the epidemiology of drowning in the city of Marseille (South of France) between 2000 and 2011. We identified 449 cases of unintentional drowning. The highest incidence was found among males with a median age of 36 years. The incidence was 5.3 victims per 10,000 inhabitants with a mortality rate of 1.2 per 10,000. These accidents occurred mainly at sea (89%) and during the summer season. A majority of drowning victims (69%) were admitted in a hospital. This is the only study in France to analyse data on drowning throughout the year and over a long period. Drowning is a serious condition burdened by 22% of victims who die.

Prevalence of Enterotoxin Genes and spa Genotypes of Methicillin-resistant Staphylococcus aureus from a Tertiary Care Hospital in China

OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes a variety of infections. MRSA has evolved resistance to multiple antibiotics. Genetic background and virulence differs in different geographic regions. The present study was aimed to investigate the prevalence of enterotoxin genes and spa genotypes of hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) isolated from a tertiary care hospital of Jiangsu province, China.

MATERIALS AND METHODS

HA-MRSA isolates from August 2013 to April 2014 at a tertiary care hospital of China were collected. We investigated antimicrobial pattern, spa types, SCCmec types and the presence of 14 virulence genes.

RESULTS

Eighty HA-MRSA isolates were collected. Results from SCCmec typing revealed that 73.8% were type II; 13.8% were type III; 12.5% were type V. There were 19 different spa types. Spa type t2460 was the most common (35.0%), followed by t002 (11.3%). CC5 was the predominant MLST CCs type (50%). The most frequent toxin genes were sea, seb, sed, sel, sen and seo (100.0%). None of the investigated isolates carried the sec or tst.

CONCLUSION

Genotypic and virulence evaluation of the isolated HA-MRSA revealed that the isolates with CC5 and SCCmec II were the predominant type and highly homological. The virulence profiles mainly existed in the genes of sea, seb, sed, sel, sen, seo and ser. The prevalence of t2460 was an outbreak and the predominant spa type.

Chamaecyparis obtusa Essential Oil Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm Formation and Expression of Virulence Factors

The emergence of antibiotic-resistant bacteria has caused difficulty in treating infectious diseases. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly recognized antibiotic-resistant bacteria. Novel antibiotics are urgently required to treat these bacteria. Raw materials derived from natural sources can be used for the development of novel antibiotics, such as Chamaecyparis obtusa (C. obtusa), which has been traditionally used in treating asthmatic disease. In this study, the antibacterial activity of the essential oil (EO) extracted from C. obtusa leaves against MRSA was investigated. MRSA growth and acid production from glucose metabolism were inhibited at concentrations greater than 0.1 mg/mL C. obtusa EO. MRSA biofilm formation was observed using scanning electron microscopy and safranin staining. C. obtusa EO inhibited MRSA biofilm formation at concentrations greater than 0.1 mg/mL. Using real-time polymerase chain reaction, mRNA expression of virulence factor genes, sea, agrA, and sarA, was observed. agrA expression was inhibited with C. obtusa EO concentrations greater than 0.2 mg/mL, whereas inhibition of sea and sarA expression was also observed at a concentration of 0.3 mg/mL. C. obtusa EO was analyzed by gas chromatography (GC) and GC coupled for mass spectrometry, which identified 59 constituents, accounting to 98.99% of the total EO. These findings suggest that C. obtusa EO has antibacterial effects against MRSA, which might be associated with the major components of C. obtusa EO, such as sabinene (19.06%), α-terpinyl acetate (16.99%), bornyl acetate (10.48%), limonene (8.54%), elemol (7.47%), myrcene (5.86%), γ-terpinene (4.04%), and hibaene (3.01%).

Antibiotics in South Indian coastal sea and farmed prawns (Penaeus monodon)

Sulphonamides and chloramphenicol antibiotics were analysed by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in sea and farmed prawn (Penaeus monodon) samples obtained from the coastal region of southern India during 2011-2012. Average recoveries were 77-99% and precision was between 1% and 8%. The results revealed that in sea prawn samples neither of the two antibiotics was detected, but in farmed samples from coastal Andhra Pradesh some sulphonamides were detected in a concentration range greater than the maximum residual limit as set by Council Directive 2377/90 EC.

Assessment of the bacteriocinogenic potential of marine bacteria reveals lichenicidin production by seaweed-derived Bacillus spp

The objectives of this study were (1) to assess the bacteriocinogenic potential of bacteria derived mainly from seaweed, but also sand and seawater, (2) to identify at least some of the bacteriocins produced, if any and (3) to determine if they are unique to the marine environment and/or novel. Fifteen Bacillus licheniformis or pumilus isolates with antimicrobial activity against at least one of the indicator bacteria used were recovered. Some, at least, of the antimicrobials produced were bacteriocins, as they were proteinaceous and the producers displayed immunity. Screening with PCR primers for known Bacillus bacteriocins revealed that three seaweed-derived Bacillus licheniformis harbored the bli04127 gene which encodes one of the peptides of the two-peptide lantibiotic lichenicidin. Production of both lichenicidin peptides was then confirmed by mass spectrometry. This is the first definitive proof of bacteriocin production by seaweed-derived bacteria. The authors acknowledge that the bacteriocin produced has previously been discovered and is not unique to the marine environment. However, the other marine isolates likely produce novel bacteriocins, as none harboured genes for known Bacillus bacteriocins.

Distribution of vibrio species isolated from aquatic environments with TCBS agar

Environmental bacteria grown on TCBS agar plates (TCBS strains) were investigated for the presence ofVibrio cholerae in aquatic environments. TCBS strain counts were 0.01 - 0.001 times the total viable counts in pairs of the same samples. The TCBS strains were of two types which required N(a)Cl (salt strain) and did not require N(a)Cl (non-salt strain) to grow in peptone water. Non-salt strains made up 85.3 - 92.1% of TCBS strains isolated from river water. TCBS strains isolated from an estuary contained 40.9% of non-salt strains and 57.4% of salt strains. Salt strains made up 69.2 - 86.8% of TCBS strains isolated from seawater. The percentages ofVibrio species in TCBS strains were 11.9 - 47.9%. V.alginolyticus andV. parahaemolyticus were isolated from seawater.V. vulnificus was only isolated from estuary water.V. cholerae non-Ol was isolated from both river water and estuary water which had low salinity.V. fluvialis was isolated from all three aquatic environments. This investigation suggests thatVibrio species were present in each sample station and thatV. cholerae existed in river water.