Methicillin-resistant Staphylococcus Aureus Colonies Research Articles

Enhanced Effect of Patient Room Disinfection Against Carbapenem-Resistant Enterobacter cloacae and Methicillin-Resistant Staphylococcus aureus Using UV-C Irradiation in Conjunction with UV-C Containment Unit.

Background/Objectives: In environments with high-frequency contact surfaces, drug-resistant bacteria, such as carbapenem-resistant Enterobacterales and methicillin-resistant Staphylococcus aureus (MRSA), can survive for extended periods, contributing to healthcare-associated infections. Ultraviolet (UV)-C irradiation often fails to adequately disinfect shadowed areas, leading to a persistent contamination risk. We evaluated the effectiveness of using a UV-C containment unit (UVCCU) in conjunction with UV-C irradiation to improve the sterilization effects on both direct and indirect surfaces, including shadowed areas, and to assess the leakage of UV radiation to the surroundings. Methods: In a model patient room, agar media inoculated with carbapenem-resistant Enterobacter cloacae and MRSA were placed at multiple locations on direct and indirect surfaces around the bed. We used the UV-C irradiation system, UVDI-360, to irradiate the bedroom-environment surfaces with and without a UVCCU. The reduction in bacterial colony counts with and without the UVCCU was measured by counting colony-forming units and calculating the log reduction values, and the UV radiation leakage outside the UVCCU was measured. Results: The use of the UVCCU led to a significant reduction in MRSA colony counts, even in shadowed areas that had previously been inadequately disinfected (with the UVCCU: 2.7 [2.7-2.8]; without the UVCCU: 0.6 [0.5-0.7]; p < 0.01). Additionally, the use of the UVCCU kept the UV radiation leakage to the surrounding environment within regulated limits. Conclusions: These findings suggest that a UVCCU can enhance the disinfection efficacy for multidrug-resistant organisms on healthcare environmental surfaces. The portability and ease of use of the UVCCU indicate its promise as an auxiliary device for UV-C disinfection in healthcare settings.

Semi-Interpenetrating Hydrogel with Long-Term Intrinsic Antibacterial Properties Promotes Healing of Infected Wounds In Vivo.

Bacterial infections significantly deteriorate the process of wound healing. The wound dressings loaded with antimicrobials are widely used to reduce bacterial infections. However, release-based sterilization may increase the risk of drug resistance of bacteria and complicate translation. Thus, the development of long-term intrinsic antibacterial wound dressings is highly desirable. In this study, an intrinsic antibacterial hydrogel (PVA/PPG-HBPL) consisting of poly(vinyl alcohol) (PVA), poly(polyethylene glycol methyl ether methacrylate-co-glycidyl methacrylate) (PPG), and hyperbranched poly-l-lysine (HBPL) was designed and fabricated. The mechanical properties of the PVA/PPG-HBPL hydrogel were enhanced by hydrogen bonding and semi-interpenetrating networks. It also possessed a favorable ability to absorb the wound exudates. The release of antibacterial HBPL was significantly decreased by the methods of cyclic freeze-thawing and covalent cross-linking during hydrogel fabrication, enabling the PVA/PPG-HBPL hydrogel with intrinsic and long-term antibacterial performance. The PVA/PPG-HBPL hydrogel dressing killed 99.9% of methicillin-resistant Staphylococcus aureus (MRSA) cultured on its surface without observable cytotoxicity in vitro. It observably shortened the healing process by 2 orders of magnitude of MRSA colonies compared with the control in the MRSA-infected full-thickness skin wound of rats in vivo even after being soaked in phosphate-buffered saline (PBS) for 21 days (PBS was changed every 3 days). The antibacterial hydrogels could kill wound bacteria in a timely manner, significantly reduce inflammatory cell infiltration, and promote neovascularization and collagen deposition.

An antibacterial and anti-oxidant hydrogel containing hyperbranched poly-l-lysine and tea polyphenols accelerates healing of infected wound

Both bacteria-infection and excessive inflammation delay the wound healing process and even create non-healing wound, thus it is highly desirable to endow the wound dressing with bactericidal and anti-oxidation properties. Herein an antibacterial and antioxidation hydrogel based on Carbomer 940 (CBM) and hydroxypropyl methyl cellulose (HPMC) loaded with tea polyphenols (TP) and hyperbranched poly-l-lysine (HBPL) was designed and fabricated. The hydrogel killed 99.9 % of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) at 107 CFU mL−1, and showed strong antioxidation against H2O2 and 2,2-di(4-tert-octylphenyl)-1-picryl-hydrazyl (DPPH) radicals without noticeable cytotoxicity in vitro. The CBM/HPMC/HBPL/TP hydrogel significantly shortened the inflammatory period of the MRSA-infected full-thickness skin wound of rats in vivo, with 2 orders of lower MRSA colonies compared with the blank control, and promoted the wound closure especially at the earlier stage. The inflammation was suppressed and the vascularization was promoted significantly as well, resulting in reduced pro-inflammatory factors including interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), and increased anti-inflammatory factors such as interleukin-4 (IL-4) and interleukin-10 (IL-10).

Neutrophil-targeted combinatorial nanosystems for suppressing bacteremia-associated hyperinflammation and MRSA infection to improve survival rates

There is currently no specific and effective treatment for bacteremia-mediated sepsis. Hence, this study engineered a combinatorial nanosystem containing neutrophil-targeted roflumilast-loaded nanocarriers and non-targeted fusidic acid-loaded nanoparticles to enable the dual mitigation of bacteremia-associated inflammation and methicillin-resistant Staphylococcus aureus (MRSA) infection. The targeted nanoparticles were developed by conjugating anti-lymphocyte antigen 6 complex locus G6D (Ly6G) antibody fragment on the nanoparticulate surface. The particle size and zeta potential of the as-prepared nanosystem were about 200 nm and −25 mV, respectively. The antibody-conjugated nanoparticles showed a three-fold increase in neutrophil internalization compared to the unfunctionalized nanoparticles. As a selective phosphodiesterase (PDE) 4 inhibitor, the roflumilast in the nanocarriers largely inhibited cytokine/chemokine release from the activated neutrophils. The fusidic acid-loaded nanocarriers were vital to eliminate biofilm MRSA colony by 3 log units. The nanoparticles drastically decreased the intracellular bacterial count compared to the free antibiotic. The in vivo mouse bioimaging demonstrated prolonged retention of the nanosystem in the circulation with limited organ distribution and liver metabolism. In the mouse bacteremia model, the multifunctional nanosystem produced a 1‒2 log reduction of MRSA burden in peripheral organs and blood. The functionalized nanosystem arrested the cytokine/chemokine overexpression greater than the unfunctionalized nanocarriers and free drugs. The combinatory nanosystem also extended the median survival time from 50 to 103 h. No toxicity from the nanoformulation was found based on histology and serum biochemistry. Furthermore, our data proved that the active neutrophil targeting by the versatile nanosystem efficiently alleviated MRSA infection and organ dysfunction caused by bacteremia. Statement of significanceBacteremia-mediated sepsis poses a significant challenge in clinical practice, as there is currently no specific and effective treatment available. In our study, we have developed a novel combinatorial nanosystem to address this issue. Our nanosystem consists of neutrophil-targeted roflumilast-loaded nanocarriers and non-targeted fusidic acid-loaded nanoparticles, enabling the simultaneous mitigation of bacteremia-associated inflammation and MRSA infection. Our nanosystem demonstrated the decreased neutrophil activation, effective inhibition of cytokine release, elimination of MRSA biofilm colonies, and reduced intracellular bacterial counts. In vivo experiments showed prolonged circulation, limited organ distribution, and increased survival rates in a mouse bacteremia model. Importantly, our nanosystem exhibited no toxicity based on comprehensive assessments.

D-Serine inhibits the attachment and biofilm formation of methicillin-resistant Staphylococcus aureus

IntroductionAlthough therapeutic agents for methicillin-resistant Staphylococcus aureus (MRSA) are clinically available, MRSA infection is still a life-threatening disease. Bacterial attachment and biofilm formation contribute significantly to the initiation of MRSA infection. Controlling MRSA’s attachment and biofilm formation might reduce the frequency of MRSA infection. According to recent data, some amino acids can reduce MRSA’s attachment on plates; however, their precise inhibitory mechanisms remain unclear. Therefore, we explored the effect of the amino acids on bacterial adhesion and biofilm formation in vitro and in vivo MRSA infection models. MethodsWe tested the inhibitory effect of amino acids on MRSA and Escherichia coli (E. coli) in the attachment assay. Moreover, we evaluated the therapeutic potential of amino acids on the in vivo catheter infection model. ResultsAmong the amino acids, D-Serine (D-Ser) was found to reduce MRSA’s ability to attach on plate assay. The proliferation of MRSA was not affected by the addition of D-Ser; thus, D-Ser likely only played a role in preventing attachment and biofilm formation. Then, we analyzed the expression of genes related to attachment and biofilm formation. D-Ser was found to reduce the expressions of AgrA, SarS, IcaA, DltD, and SdrD. Moreover, the polyvinyl chloride catheters treated with D-Ser had fewer MRSA colonies. D-Ser treatment also reduced the severity of infection in the catheter-induced peritonitis model. Moreover, D-Ser reduced the attachment ability of E. coli. ConclusionD-Ser inhibits the attachment and biofilm formation of MRSA by reducing the expression of the related genes. Also, the administration of D-Ser reduces the severity of catheter infection in the mouse model. Therefore, D-Ser may be a promising therapeutic option for MRSA as well as E. coli infection.

Risk of Urban Zoonosis from Geese Colonized with Antimicrobial Resistant Bacteria

Abstract Introduction/Objective Zoonotic disease occurs through direct fecal contact with increased exposure resulting in higher infection rates. Antimicrobial resistant colonization occurs in wild birds, however the spread of microbial resistance correlates with increased human activity. Anchorage actively develops urban park environments with pastoral lawns and abundant water sources creating an inviting habitat for human and geese populations. By 2018, Alaska Fish and Game reported a 10-fold increase in migrating Canadian Geese resulting in significant environmental damage, including fecal contamination. At the same time, Anchorage experienced an uptake use of their parks and costal trails for both recreation and homeless camps. To determine potential exposure, sixty-eight geese fecal samples were collected in fourteen urban park locations. Methods Fecal samples were incubated in thioglycolate broth at 37oC for 24 hours then cultured to chromogenic screening agar for vancomycin resistant enterococcus (VRE), methicillin resistant Staphylococcus aureus (MRSA), and extended spectrum beta-lactamase (ESBL) enterobacteriaceae. Potential MRSA, VRE or ESBL colonies were further identified using standard biochemical testing with confirmation of antimicrobial resistance by disk diffusion. Results Forty percent of all fecal samples collected were colonized with VRE or ESBL producing Escherichia coli with eighty-six percent of collection sites positive for one or more antimicrobial resistant bacterium. Seven percent of fecal samples were positive for both organisms. MRSA was not identified. The highest concentration of antimicrobial resistant bacteria was discovered on the Campbell Creek Trail (83%), which winds alongside Providence Hospital. Conclusion Transmission of infectious agents can occur due to environmental exposure, which increases in individuals who are either housing insecure or chronically homeless. Urban green spaces are often sites for unregulated camping by individuals who lack consistent residential housing. Discovery of antimicrobial resistant colonization in geese populating nearly ninety percent of Anchorage’s parks and trails creates a significant public health issue, with the homeless population targeted for poor outcome due to their immunocompromised status. Continued evaluation is essential to predict infection risk and impact on healthcare delivery, especially in vulnerable populations.

Indoor Finish Material Influence on Contamination, Transmission, and Eradication of Methicillin-Resistant Staphylococcus aureus (MRSA).

Objective:The purpose of this study was to evaluate environmental surface materials used in healthcare environments for material composition, methicillin-resistant Staphylococcus aureus (MRSA) viability, and a comparison of two disinfectants, a bleach germicidal cleaner and Decon7, a novel disinfectant.Background:Contaminated environmental surfaces have been associated with outbreaks of healthcare-associated illness (HAIs). One in every 20 patients in U.S. acute care hospitals acquire a healthcare-associated illness, leading to consequences such as elevated morbidity, mortality, and a decrease in quality of life. In the patient environment, MRSA can remain viable from hours to up to 14 days.Methods:Environmental surface materials were evaluated as new and worn. Material composition and properties were assessed to evaluate surface integrity and the influence on the disinfection of MRSA. Inoculated materials were used to assess MRSA viability over time and the efficacy of a manufacturer’s recommended cleaning and disinfection product compared to a novel disinfectant.Results:Environmental surface materials respond differently in appearance and roughness, when mechanically worn. When measuring MRSA survival, at 24 hr, MRSA colony forming unit (CFU) counts were reduced on the copper sheet surface and solid surface with cupric oxide. By 72 hr, all MRSA counts were zero. Bleach and the novel disinfectant were equally effective at disinfecting MRSA from all surface types.Conclusions:This study highlights a gap in knowledge about the impact of type and wear of environmental surface materials used in healthcare environments on contamination with epidemiologically important organisms. In conclusion, environmental surface material wear, properties, and cleaning and disinfection efficacy are important factors to consider when addressing HAIs.

Colonization of Methicillin-Resistant Staphylococcus aureus (MRSA) among Medical Students in Tertiary Institution in Central Malaysia.

Methicillin-resistant Staphylococcus aureus or MRSA infection is virulent and presents with a broad spectrum of severity. Limited regional reports that specifically outlined the potential risk of medical students being part of the dissemination of MRSA in healthcare settings were noted. This study aims to assess the prevalence and contributory factors of colonization of MRSA on neckties, headscarves, and ID badges among medical students in a local medical university in Malaysia. A cross-sectional study was conducted involving 256 medical students. A validated questionnaire was used to collect the data, and sample swabs were collected between July and August 2013 by swabbing neckties, headscarves, or identification badges. The swabs were then streaked onto mannitol salt agar (MSA) and incubated at 37 °C overnight. Out of 433 samples taken, 40 swabs (9.24%) were positive for Staphylococcus aureus. Out of the 40 swabs, five (12.5%) isolates were MRSA (one culture was isolated from the headscarf of a preclinical student, one culture was isolated from the necktie of clinical students, while the remaining three were isolated from identification badges of clinical students. There was no significant association between age, gender, ethnicity, and phase of medical students with the colonization of MRSA (p > 0.05). There was a significant association between knowledge score on hand hygiene practice and phase of medical students. MRSA colonies were present on neckties, headscarves, and identification badges of medical students of all phases. The findings from this study suggest the need for improvement of hand hygiene knowledge and discontinuity of mandatory use of physical ID badges and neckties among medical students.

European hedgehogs (Erinaceus europaeus) as a natural reservoir of methicillin-resistant Staphylococcus aureus carrying mecC in Denmark.

ObjectivesA recent study from Sweden showed that European hedgehogs may constitute a reservoir for methicillin-resistant Staphylococcus aureus (MRSA), but this host-parasite relationship remains to be investigated in other countries. In this study, we therefore sought to: 1) determine the dissemination of MRSA in European hedgehogs throughout Denmark; 2) investigate determinants of MRSA carriage in hedgehogs; 3) determine the potential for zoonotic transmission of MRSA from hedgehogs to humans; and 4) characterise the detected MRSA on both a phenotypic and molecular level.MethodsNasal swabs were taken from 188 dead hedgehogs collected by volunteers throughout Denmark to determine the occurrence of MRSA. Additionally, 16 hedgehog rehabilitators were tested for potential zoonotic transmission of MRSA from hedgehogs to humans. The swabs were incubated in tryptic soy broth supplemented with 6.5% NaCl, followed by spread of 10 μl on Brilliance MRSA 2 agar. One presumptive MRSA colony from each plate was subcultured on 5% blood agar. All S. aureus subcultures were verified by a PCR assay detecting mecA, mecC, lukF-PV, scn, and spa, followed by spa typing.ResultsA total of 114 (61%) hedgehogs carried mecC-MRSA, whereas none carried mecA-MRSA. The detected mecC-MRSA belonged to two genetic lineages CC130 (spa-types: t528, t843, t1048, t3256, t3570, t6220, t17133) and CC1943 (spa-types: t978, t2345, t3391, t8835, t16868), 52% of which were spa-type t843 (CC130).The detection rate of mecC-MRSA in the hedgehogs was similar regardless of cause of death, sex, region and habitat type. None of the hedgehog rehabilitators carried MRSA.ConclusionsThis nationwide study confirms a high occurrence of mecC-MRSA in hedgehogs, which could serve as a natural reservoir for this specific type of MRSA. Furthermore, our study did not find signs of zoonotic transmission of mecC-MRSA to hedgehog rehabilitators.

Benzalkonium chloride effectiveness as a disinfectant against hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA)

Aims: Benzalkonium chloride is used to disinfect hospital instruments to prevent nosocomial infection caused by microorganisms, such as Methicillin Resistant Staphylococcus aureus (MRSA). There are strains of MRSA isolated from hospitals that were found to be resistant towards benzalkonium chloride. This research was aimed to compare the affectivity of different concentrations of benzalkonium chloride to inhibit the growth of Hospital-Associated MRSA (HA-MRSA) and determine the Minimum Inhibitory Concentration (MIC) of benzalkonium chloride against HA-MRSA. Methodology and results: The samples were five HA-MRSA isolates obtained from Dr. Soetomo Hospital Surabaya. It was identified by amplification of SCCmec genes. The HA-MRSA with SCCmec type III was divided into six flasks based on the concentration of benzalkonium chloride in their inoculation media (0 μg/mL, 0.625 μg/mL, 1.25 μg/mL, 2.5 μg/mL, 5 μg/mL, and 10 μg/mL). The growth of HA-MRSA in media was determined by the number of colonies after treatment. The result showed that the MIC of benzalkonium chloride for HA-MRSA was 5 μg/mL, where no growth of bacterial was observed. There was significant difference in MRSA colony count between different groups of benzalkonium chloride concentrations (P = 0.001), and there was negative correlation between benzalkonium chloride concentration and HA-MRSA growth (P = 0.0001 and r = ─0.880). Conclusion, significance and impact of study: The concentration of benzalkonium chloride influences the growth of HA-MRSA. The higher the concentration, the fewer HA-MRSA growth. Application of benzalkonium chloride according to MIC will prevent HA-MRSA resistance towards benzalkonium chloride.

Anti-inflammatory effect of Garcinia mangostana Linn. pericarp extract in methicillin-resistant Staphylococcus aureus-induced superficial skin infection in mice

Garcinia mangostana (mangosteen) pericarp has antibacterial effects; however, information regarding its anti-inflammatory activity in vivo is limited. The anti-inflammatory effect of G. mangostana pericarp extract against methicillin-resistant Staphylococcus aureus (MRSA)-induced superficial skin infection was investigated in mice using a tape stripping model. G. mangostana pericarp ethanolic extract (GME) and its constituent, α-mangostin, were topically administered to mice with MRSA-induced superficial skin infection. MRSA-infected wounds treated with GME were completely healed on the 10th day of the study and the number of MRSA-colonies decreased from the first day of the study, whereas α-mangostin-treated wounds never completely healed with higher numbers of MRSA colonies. The epidermis of GME-treated wounds had nearly completely regenerated, with no inflammatory cell infiltration. In contrast, α-mangostin-treated wounds exhibited neutrophil infiltration and accumulation of mast cells. MRSA-infected wounds without treatment showed high expression of TNF-α, IL-6, IL-1β, and TLR-2 genes. In contrast, GME decreased mRNA levels, restoring expression of those genes to normal levels. Notably, α-mangostin did not down-regulate the expression of pro-inflammatory cytokines to the same extent as GME. Hence, GME is a promising alternative MRSA treatment because of its antibacterial, anti-inflammatory, and wound healing effects.

Shorter Incubation Times for Detecting Multi-drug Resistant Bacteria in Patient Samples: Defining Early Imaging Time Points Using Growth Kinetics and Total Laboratory Automation.

BackgroundThe transition from manual processing of patient samples to automated workflows in medical microbiology is challenging. Although automation enables microbiologists to evaluate all samples following the same incubation period, the essential incubation times have yet to be determined. We defined essential incubation times for detecting methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant gram-negative bacteria (MDRGN), and vancomycin-resistant enterococci (VRE).MethodsWe monitored the growth kinetics of MRSA, MDRGN, and VRE between two and 48 hours on chromogenic media to establish the time points of first growth, single colony appearance, and typical morphology for 102, 104, 106, and 108 colony forming units/mL. Subsequently, we imaged plates inoculated with 778 patient samples after 20, 24, and 36 hours.ResultsThe first growth, single colony appearance, and typical morphology time points were inoculum-dependent. First growth appeared after 6–18 hours, 4–18 hours, and 8–48 hours for MRSA, MDRGN, and VRE, respectively, and single colonies appeared at 12–18 hours, 6–20 hours, and 12–48 hours, respectively. Typical morphology was visible at 14–22 hours and 12–48 hours for MRSA and VRE, but was not determined for MDRGN. By examining patient samples, ≥98% of MRSA and MDRGN were visible 20 hours after the start of incubation. Following 24 hours of incubation, only 79.5% of VRE were clearly visible on the respective plates.ConclusionsAn incubation time of 20 hours is sufficient for detecting MRSA and MDRGN. VRE growth is much slower and requires additional imaging after 36 hours.

Efficient processing of MRSA screening specimens by a modified inoculation protocol.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections and mortality, and therefore constitutes a serious cost factor in public health. Culture-based MRSA screening is a crucial part of MRSA-infection prevention and control strategies in the hospital setting. Manual inoculation of screening swabs onto culture plates still constitutes the major part of the technicians' workload in laboratories. We present a modified inoculation protocol that comprises direct inoculation of specimen onto a chromogenic MRSA-selective agar plate without further streaking for isolation. This study aims to evaluate the impact of this inoculation protocol on technicians' workload and the downstream workflow in our laboratory. Batches of 50 specimens were processed by different technicians and the hands-on time was compared between the standard and modified inoculation protocol. To assess the impact on downstream processing, a retrospective analysis of the rate of subcultures and turnaround time (TAT) of specimens yielding putative MRSA colonies from 9months before (n = 1548) and after (n = 1267) the protocol change was carried out based on laboratory information system (LIS) data. The implementation of the modified protocol significantly reduced technicians' hands-on time needed for inoculation by 26.5% without altering the overall turnaround time of surveillance cultures or causing higher costs for extra plates needed for subcultures. Our modified inoculation protocol offers a cost-effective and easy to implement procedure for MRSA surveillance cultures which significantly decreases technicians' workload and does not impede the downstream workflow. It therefore increases the capacity of laboratory technicians' to execute more demanding tasks.

Far-UVC light prevents MRSA infection of superficial wounds in vivo.

BackgroundPrevention of superficial surgical wound infections from drug-resistant bacteria such as methicillin resistant Staphylococcus aureus (MRSA) currently present major health care challenges. The majority of surgical site infections (SSI) are believed to be caused by airborne transmission of bacteria alighting onto the wound during surgical procedures. We have previously shown that far-ultraviolet C light in the wavelength range of 207–222 nm is significantly harmful to bacteria, but without damaging mammalian cells and tissues. It is important that the lamp be fitted with a filter to remove light emitted at wavelengths longer than 230 nm which are harmful.AimsUsing a hairless mouse model of infection of superficial wounds, here we tested the hypothesis that 222-nm light kills MRSA alighting onto a superficial skin incisions as efficiently as typical germicidal light (254 nm), but without inducing skin damage.MethodsTo simulate the scenario wherein incisions are infected during surgical procedures as pathogens in the room alight on a wound, MRSA was spread on a defined area of the mouse dorsal skin; the infected skin was then exposed to UVC light (222 nm or 254 nm) followed by a superficial incision within the defined area, which was immediately sutured. Two and seven days post procedure, bactericidal efficacy was measured as MRSA colony formation unit (CFU) per gram of harvested skin whereas fixed samples were used to assess skin damage measured in terms of epidermal thickness and DNA photodamage.ResultsIn the circumstance of superficial incisions infected with bacteria alighting onto the wound, 222-nm light showed the same bactericidal properties of 254-nm light but without the associated skin damage.ConclusionsBeing safe for patient and hospital staff, our results suggested that far-UVC light (222 nm) might be a convenient approach to prevent transmission of drug-resistant infectious agents in the clinical setting.

Methicillin-resistant Staphylococcus aureus in the environment of public transport: data from the metropolitan network in Lyon, France

Methicillin-resistant Staphylococcus aureus (MRSA) is involved in community-acquired and nosocomial diseases. The means of MRSA transmission and dissemination in the community remain uncertain. Studies have shown that public transport systems could be a source of MRSA and may serve as a potential source for community-acquired MRSA infections. This study aimed to investigate MRSA contamination on Lyon's metropolitan network (Métro) in France. Hand-touched surfaces were sampled with sterile swabs (Transystem®) during a 1-day transversal study by collecting 50 samples in seven hub stations and two trains for each of the four Métro lines. Then, during a longitudinal study, one sample was collected twice daily for 30 consecutive days in the busiest and most congested hub station. All swabs were incubated in enrichment medium for 24 h and then each suspension was plated onto a chromogenic selective medium for MRSA. After 24 h at 36 °C, all presumptive MRSA colonies were tested using VITEK® MS to confirm identification as S. aureus as well as by Alere™ PBP2a Culture Colony Test and mecA/mecC PCR to check methicillin resistance. Of the 110 swabs tested, 24 presumptive MRSA colonies were isolated, of which 2 were confirmed as S. aureus by VITEK® MS. These two isolates were tested negative using the PBP2a Culture Colony Test and PCR. Unlike other foreign cities such as Lisbon, the current data suggest a low level of MRSA contamination of hand-touched surfaces on Lyon's Métro. This should be put in perspective with the low level of MRSA colonisation in the French community.

Increased use of surgical energy promotes methicillin-resistant Staphylococcus aureus colonization in rabbits following open ventral hernia mesh repair.

Surgical energy has been widely implemented because of ease of use, effective hemostasis, and surgical dissection. Studies demonstrate its use to be an independent risk factor for postoperative wound infection. Methicillin-resistant Staphylococcus aureus (MRSA) is the most common bacteria found in postoperative mesh infection. No reports are available on the sequelae of surgical energy use for open ventral hernia repair (oVHR) with mesh. We hypothesized that increasing amounts of surgical energy will result in higher infectious burden after oVHR with composite multifilament polyester mesh (Parietex™ PCO). New Zealand rabbits underwent bridging oVHR with Parietex™ PCO and were divided into three surgical treatment groups: (1) scalpel alone, (2) 120J of energy, and (3) 600J of energy. The bioprosthesis was then inoculated with 105 colony-forming units of MRSA. Rabbits were survived for 7 days with daily physical examination. Complete blood count, basci metabolic panel, and blood cultures were performed on postoperative days one, four, and seven. Surviving rabbits were killed, and meshes explanted for MRSA colony counts. Rabbits receiving the most surgical energy developed signs and symptoms of severe sepsis and wound necrosis within 24h. In comparison, rabbits receiving no surgical energy had significantly less MRSA recovered from explanted mesh, significantly less bacteremia, and fewer adhesions. Increased use of surgical energy promoted greater colonization, exaggerated septic response to bacterial contamination, and more severe adhesions. In the absence of devitalized tissue, rabbits can effectively limit bacterial contamination. These findings support the surgical principles of proper tissue handling and highlight the detrimental effects of indiscriminant surgical energy usage, thus emphasizing the importance of programs such as Fundamental Use of Surgical Energy.

In vivo antibacterial activity of Garcinia mangostana pericarp extract against methicillin-resistant Staphylococcus aureus in a mouse superficial skin infection model

Context: Garcinia mangostana Linn. (Guttiferae) (GM) pericarp has been shown to exhibit good in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA); however, there is currently no available information regarding its in vivo antibacterial activity.Objective: To examine in vivo antibacterial activity of G. mangostana extract against MRSA.Materials and methods: GM pericarp was extracted by ethanol (GM-EtOH) and methanol (GM-MeOH). The crude extracts were examined for in vitro antibacterial activity against MRSA using broth microdilution assay. The in vivo antibacterial activity of 10% GM-EtOH against MRSA was determined in a tape stripping mouse model of superficial skin infection for 9 days by evaluating transepidermal water loss (TEWL) and performing colony counts from cultured swabs.Results: GM-EtOH showed greater in vitro activity against MRSA than GM-MeOH in broth microdilution assay with minimum inhibitory concentration 17 versus 20 μg/mL and minimum bactericidal concentration 30 versus 35 μg/mL, respectively. The GM-EtOH (13.20 ± 0.49%) contained α-mangostin more than the GM-MeOH (9.83 ± 0.30%). In the tape stripping mouse model, 10% GM-EtOH reduced the number of MRSA colonies (0–1) recovered from infected wounds (>100 colonies) on the first day of treatment, restored TEWL to normal levels on the fourth day, and had completely healed the wounds by day 9.Conclusion: GM-EtOH showed promising in vivo antibacterial activity against MRSA in a superficial skin infection model in mice. It is of interest to develop a topical formulation of GM-EtOH to further study its potential as a novel antibacterial agent.

A Preliminary Assessment of Contamination of Emergency Service Helicopters with MRSA and Multi-Resistant Staphylococcus aureus

Objective: To detect the presence of methicillin-resistant Staphylococcus aureus (MRSA) and multi-resistant S. aureus (Multi-RSA) in emergency service helicopters. Methods: This proof-of-concept study used a convenience sample of two emergency service helicopters located in different Australian towns. Over a three-month period ending January 31 2015, within each helicopter five areas of perceived high contact were sampled by taking swabs on an approximately weekly basis. The precise occasions varied based on timings of cases and maintenance schedules. Swabs were analysed for the presence of MRSA, Multi-RSA and other bacteria. Results: Presumptive MRSA and other colonies were recovered from each helicopter. Of those presumptive colonies tested, 18.7% were identified as Staphylococcus aureus, 76.0% were other staphylococci (such as S. epidermidis), and 5.3% were other genera of bacteria. Further testing of these colonies detected no MRSA or Multi- RSA. Over the period of this study, high total numbers of bacteria were recovered in both helicopters. Typically, the floor of the helicopters had higher counts than the seat belts and the blood pressure cuff containers, whereas the radio and cardiac equipment had comparatively lower counts. Conclusions: Since a total of 94.7% of the colonies tested were identified as Staphylococcus spp. the potential for the existence of MRSA in emergency service helicopters is apparent. Our findings highlight the importance of regular cleaning in emergency service vehicles to promote the reduction of infectious disease transmission. We recommend the implementation of a standard operating procedure for cleaning and disinfection across all emergency service providers, reinforced by appropriate infection control training. For quality control, random intermittent swab testing of selected surfaces within all helicopters is advised. The implications of our findings may assist emergency medical service providers to reduce infectious disease transmission risks, and may help to minimise exposure to pathogenic microorganisms during disaster events including pandemics and bioterrorism.

Antimicrobial in vitro Study of Cosmos caudatus H.B.K Leaves Extract Towards Methicillin-Resistant Staphylococcus aureus (MRSA)

Cosmos caudatus H.B.K leaves is known to have many active substances with antimicrobial effect such as saponin, flavonoid, poliphenol, volatile oil, costunolide, and 4,4’-bipyridin. This research is conducted to prove the antimicrobial effect of Cosmos caudatus leaves extract on gram positive Methicillin-Resistant Staphylococcus aureus (MRSA) in vitro. The sample of this research is served by Microbiology Laboratorium of Brawijaya University. An experimental study with tube dilution method was carried out. The treated groups are groups of bacteria treated with Cosmos caudatus leaves extract with a range concentrations of 14%; 12%; 10%; 8%; and 6%. The control group is groups treated with 0% extract. The result indicates that the MIC (Minimal Inhibitory Concentration) can not be observed due to the extract’s turbid green colour. The MBC (Minimal Bactericidal Concentration) is 14% for MRSA. Data analysis with CI=95% shows a significant difference of effects on the number of MRSA colonies growth (Anova, p = 0,000) with the change of extract concentrations. The correlation regression test shows a strong association between the extract concentration and the number of colonies growth (Correlation, r = -0,754, p=0,000). Cosmos caudatus leaves extract has antimicrobial effect on MRSA.Keywords : Cosmos caudatus leaves estract, Methicillin-Resistant Staphylococcus aureus (MRSA), antimicrobial.

Methicillin-resistant Staphylococcus aureus: A phantom or true menace in our neonates?

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important health care-associated pathogen, but community-acquired MRSA has emerged as a pathogen in children without established risk factors. S. aureus nasal carriage is a risk factor for infection in humans, particularly in hospitals, and appears to antedate bacteremic as well as non-bacteremic infection. A cross sectional study was implemented from July 2004 to 2006 in Mofid Children’s Hospital. Trained technicians obtained nasal swab samples from neonates. Questionnaires were completed for each and MRSA colonies were detected. One thousand and three hundred and sixty six neonates were included in this study. Age on admission had direct correlation with staphylococcus colonization. History of previous antibiotic consumption had an indirect relationship with nasal colonization. We did not find any correlation between MRSA colonization and different variables (such as birth weight, age, sex, history of antibiotic consumption). These predictors may help inform clinical decision making when starting empiric antibiotic therapy. First, older neonates admitted to the ward are more likely to be carriers of S. aureus. When clinicians encounter infections in this group, especially in areas of the body where staphylococcal infections are common, such as the skin, treatment should include an antibiotic that is effective against S. aureus. Fortunately, MRSA carriage rate is low in our neonates; therefore, clinicians should not start antibiotic therapy against MRSA until the presence of this organism is documented by laboratory methods.