Bactericidal Effect of Selenium Nanoparticles Combined with Povidone-iodine on Pathogenic Bacteria in Surgical Site Infection / 中山大学学报(医学科学版)

ObjectiveTo investigate the bactericidal effect of loaded multifunctional povidoneiodine-nanometer selenium （PVP-I@Se） disinfectant on Staphylococcus aureus （SA） and methicillin-resistant Staphylococcus aureus （MRSA）， and to provide an experimental basis for the reduction of surgical site infection （SSI）. MethodsThe control group was the povidone iodine （PVP-I） group with different concentrations of iodine （50， 75， 100， 200 and 400 μg/mL）. The PVP-I@Se group （experimental group） was the PVP-I group further supplemented with 2 μg/mL Selenium nanoparticles （SeNPs）. Then we compared the bactericidal effect of the two groups of disinfectant solutions on SA and MRSA by examining the minimum inhibitory concentration （MIC）， minimum bactericidal concentration （MBC）， the shortest sterilization time at a concentration of 50 μg/mL iodine and the inhibition zone diameters at concentrations of 200 μg/mL and 400 μg/mL iodine. ResultsMIC values of PVP-I against SA and MRSA were both 79.17 μg/mL， and those of PVP-I@Se were 54.17 and 70.83 μg/mL， respectively. MBC values of PVP-I against SA and MRSA were 129.17 and 150.00 μg/mL， respectively， and those of PVP-I@Se were 70.83 and 87.50 μg/mL， respectively. At a concentration of 50 μg/mL iodine， the shortest sterilization time of PVP-I for SA and MRSA was 130 s and 140 s， respectively， and that of PVP-I@Se was 65 s and 75 s， respectively. At a concentration of 200 μg/ml iodine， the inhibition zone diameters of PVP-I for SA and MRSA were 7.67 mm and 8.33 mm， and those of PVP-I@Se were both 9.50 mm. At a concentration of 400 μg/mL iodine， the inhibition zone diameters of PVP-I for SA and MRSA were 9.00 mm and 9.33 mm， and those of PVP-I@Se were 11.67 mm and 12.00 mm， respectively. ConclusionsPVP-I with different concentrations of 50， 75， 100， 200 and 400 μg/mL iodine supplemented with 2 μg/mL SeNPs have better and faster bactericidal effect on SA and MRSA. When combined with SeNPs， PVP-I can enhance the bactericidal activity against SA and MRSA， but with better sensitizing effect on SA than MRSA and higher demand of iodine concentration （400 μg/mL） for sensitizing effect on MRSA. This study provides a theoretical basis for selecting optimal concentration and action time of the disinfectant， thus reducing SSI.

Analysis of Inhibitory Mechanism of Reyanning Mixture Combined with Linezolid Against MRSA and Its Biofilm Based on Metabonomics / 中国实验方剂学杂志

Objective:To investigate the inhibitory effects and mechanism of Reyanning mixture （RYN） combined with linezolid （LNZ） against methicillin-resistant <italic>Staphylococcus aureus</italic> （MRSA） and its biofilm. Method:The minimum inhibitory concentrations （MICs） of RYN and LNZ against MRSA were determined by microdilution assay. The microplate method was used to detect the changes in viable count before and after MRSA administration at four time points （0， 6， 12， 24 h） in the process of biofilm growth. The morphological changes of MRSA after 24 h were observed by scanning electron microscope. Metabonomic technique was applied to analyze the changes in terminal metabolites of endogenous small molecules from MRSA treated by the two drugs at four time points. Result:The MICs of RYN and LNZ were 1/2 of the stock solution concentration and 4 mg·L^-1， respectively. The inhibitory effect of LNZ （2 mg·L^-1） against viable bacteria at 0 h was better than that of 1/16 RYN. At 6， 12， 24 h， 1/16 RYN was superior to LNZ in inhibiting MRSA. The inhibitory effects of RYN combined with LNZ were better than those of RYN or LNZ alone at the four time points. RYN combined with LNZ caused more severe damages to the morphological structure of MRSA biofilm at 24 h than RYN or LNZ alone. Cyclic adenosine monophosphate （cAMP）， adenosine diphosphate （ADP）-<italic>D</italic>-ribose and 2-methylbutanoyl-coenzyme A （2M-CoA）， as the metabolites related to biofilm formation， were immune to LNZ， but 2M-CoA and ADP-<italic>D</italic>-ribose were influenced by RYN at 12 h and 24 h. The combined use of RYN and LNZ interfered with the three metabolites at 24 h. <italic>L</italic>-tryptophan， phenylpyruvic acid， cytidine and sebacic acid were the pharmacometabolic markers of LNZ， and the related biological pathways were phenylalanine， tyrosine and tryptophan biosynthesis and phenylalanine metabolism. Four metabolites such as<italic> L</italic>-histidine， uric acid， and <italic>L</italic>-lysine were the pharmacometabolic markers of RYN， with phenylalanine metabolism and aminoacyl-transfer ribonucleic acid （tRNA） biosynthesis confirmed as the related biological pathways. Nine metabolites such as <italic>L</italic>-tryptophan，<italic> L</italic>-lysine， and sphingosine-1-phosphate were responsible for the efficacy of RYN combined with LNZ. The related biological pathways involved aminoacyl-tRNA biosynthesis， phenylalanine， tyrosine and tryptophan biosynthesis， novobiocin biosynthesis， and tyrosine metabolism. Conclusion:RYN combined with LNZ better exerts the inhibitory effects against MRSA at each time point of its biofilm formation， which is attributed to cAMP metabolism. The synergistic effect resulted from aminoacyl-tRNA biosynthesis and phenylalanine， tyrosine and tryptophan biosynthesis. RYN combined with LNZ can serve as a potentially effective solution to MRSA infection.

Antimicrobial and cytotoxic activities of marine sponge-derived fungal extracts isolated from Dactylospongia sp.

This study is the first report on the antimicrobial and cytotoxic activities of fungal extracts isolated from marinesponge Dactylospongia sp., which is collected from Mandeh Island, West Sumatra, Indonesia. The isolation of fungalwas conducted using dilution method with Sabouraud Dextrose Agar + chloramphenicol (0.05%) as a medium. Thepure isolated fungal was cultivated on rice medium at temperature 25°C–27°C and then extracted using ethyl acetatesolvent. The ethyl acetate extract of each isolated fungal was tested for antimicrobial and cytotoxic activities. Ninefungal strains have been isolated from this sponge. Two ethyl acetate extracts of fungal strains (Dc03 and Dc04) werecategorized as having strong inhibition against the growth of Staphylococcus aureus, Escherichia coli, methicillinresistant S. aureus, and multidrug-resistant Pseudomonas aeruginosa in a concentration of 5% with zone inhibitionin range of 12.31 ± 0.54–16.14 ± 0.75 mm. The cytotoxic activity screening of the ethyl acetate extracts of fungalstrains was done by using the brine shrimp lethality test. Four fungal strains had LC50 below 80 µg/ml (Dc03, Dc04,Dc05, and Dc08) and were further tested with MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide)assay on T47D cell line. These selected fungi were identified molecularly as Cladosporium halotolerans MN859971,Penicillium citrinum MN859968, Aspergillus versicolor MN859970, and Aspergillus sydowii MN859969, respectively.The results suggest that these fungal strains are quite rich in the production of bioactive compounds that are veryeffective as antibacterial and cytotoxic agents

Comparison of Latex Agglutination Test with Polymerase Chain Reaction for Detection of mecA Gene in Methicillin Resistant Staphylococcus aureus

Background: Antimicrobial resistance is a devastating question that threatens health globally. The extensive, indiscriminate and unnecessary consumption of antibiotics for humans, as well as wildlife and in agriculture; lead to the development of notoriously resistant Staphylococcus aureus; through possession of mecA gene, encoded by modified Penicillin binding protein (PBP2a); being labeled “Methicillin resistant Staphylococcus aureus”. Conventional phenotypic techniques for MRSA detection rely on standardization of cultural characteristics. The latex agglutination method can be adopted as an accurate strategy for rapid detection of MRSA. Methodology: A total of 713 consecutive, non-duplicate isolates of Staphylococcus aureus were processed. Methicillin resistance was determined using cefoxitin (30 µg) by Kirby-Bauer method following Clinical and Laboratory Standards Institute (CLSI) guideline, latex agglutination method; and PCR for mecA gene. Results: The results showed that out of 713 Staphylococcus aureus isolates, 12.90% isolates were detected as MRSA due to resistance to cefoxitin. By latex agglutination method, 87 (94.50%) were positive for PBP2a; while on PCR mecA gene was detected only in 82 (89.10%) MRSA isolates. When assessed with PCR (gold standard) the sensitivity and diagnostic accuracy of latex agglutination was 100% and 94.57%, respectively. Conclusion: Latex agglutination test can be used as a prompt and reliable diagnostic technique for mecA gene detection in MRSA isolates, where molecular methods are limited. This can effectively minimize the misdiagnosis of resistant strains, and over/misuse of antibiotics.

Molecular characteristics and virulence gene profiles of Staphylococcus aureus causing bloodstream infection

ABSTRACT Background: The rate of methicillin-resistant Staphylococcus aureus (MRSA) among the total of S. aureus isolates decreased to 35.3% in 2017 in China. It is unclear whether the molecular characteristics of S. aureus isolates have changed as the rate decreased. Objective: This study aimed to investigate the molecular characteristics and virulence genes profile of S. aureus isolates causing bloodstream infection and analyze the correlation between the prevalence rates of the common sequence types and MRSA. Methods: A total of 112 S. aureus strains from eight hospitals of four cities, including 32 MRSA isolates, were identified and evaluated through multilocus sequence typing, spa typing, and determination of virulence genes. Results: Twenty-five STs were identified, of which ST5 (21.4%) was the most prevalent, whereas the prevalence of ST239 correlated with the rate of MRSA among all S. aureus isolates. Forty-six spa types were identified, of which t2460 (14.3%) was the most common. clfa, hla, seb, fnbA and hlb were the prevailing virulence genes. 81.3% MRSA and 45.0% methicillin-sensitive S. aureus (MSSA) isolates harbored six or more tested virulence genes. ST5-t2460, seldom noted in bloodborne S. aureus isolates in China, was the most common clone. The prevalence of harboring six or more virulence genes in ST5-t2460 and ST188-t189 were 93.8% and 8.3%, respectively. Conclusion: ST5-t2460 was the most common clone in S. aureus causing bloodstream infection followed by ST188-t189, which had never been noted in China before. Moreover, ST5-t2460 harbored more virulence genes than ST188-t189, and the prevalence of ST239 clone decreased with the proportion of MRSA among all S. aureus isolates.

Interaction study between vancomycin and liposomes containing natural compounds against methicillin-resistant Staphylococcus aureus clinical isolates

ABSTRACT The treatment of infections caused by resistant microorganisms is limited, and vancomycin (VAN) treatment failures for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia are not uncommon, even when MRSA clinical isolates are susceptible to VAN. Thus, this study proposed the association of VAN with usnic acid and ß-lapachone encapsulated into liposomes as a novel therapeutic option for infections caused by MRSA. Liposomes containing ß-lap (ß-lap-lipo) or usnic acid (UA-lipo) were prepared by the thin lipid film hydration method followed by sonication. Antimicrobial activity against MRSA clinical isolates was investigated by the microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). The interaction studies were carried out using the checkerboard method and epsilometer test (Etest). The interaction between VAN and ß-lap or ß-lap-lipo was synergistic (FICI = 0.453 and FICI = 0.358, respectively). An additive interaction between VAN and UA (FICI = 0.515) was found. UA-lipo resulted in synergism with VAN (FICI = 0.276). The Etest reproduced the results obtained by the checkerboard method for approximately 82% of the analysis. Thus, the present study demonstrated that VAN in combination with UA-lipo, ß-lap or ß-lap-lipo synergistically enhanced antibacterial activity against MRSA

Bases moleculares de la resistencia a meticilina en Staphylococcus aureus / Molecular basis of methicillin-resistance in Staphylococcus aureus

Resumen Desde el inicio de la era antimicrobiana se han ido seleccionando gradualmente cepas de Staphylococcus aureus resistentes a antimicrobianos de amplio uso clínico. Es así como en 1960 se describen en Inglaterra las primeras cepas resistentes a meticilina, y algunos años después son informadas en hospitales de Chile. Actualmente, S. aureus resistente a penicilinas antiestafilocóccicas es endémico en los hospitales de nuestro país y del mundo, siendo responsable de una alta morbimortalidad. La resistencia es mediada habitualmente por la síntesis de una nueva transpeptidasa, denominada PBP2a o PBP2' que posee menos afinidad por el β-lactámico, y es la que mantiene la síntesis de peptidoglicano en presencia del antimicrobiano. Esta nueva enzima se encuentra codificada en el gen mecA, a su vez inserto en un cassette cromosomal con estructura de isla genómica, de los cuales existen varios tipos y subtipos. La resistencia a meticilina se encuentra regulada, principalmente, por un mecanismo de inducción de la expresión del gen en presencia del β-lactámico, a través de un receptor de membrana y un represor de la expresión. Si bien se han descrito mecanismos generadores de resistencia a meticilina mec independientes, son categóricamente menos frecuentes.

Staphylococcus aureus isolates resistant to several antimicrobials have been gradually emerged since the beginning of the antibiotic era. Consequently, the first isolation of methicillin-resistant S. aureus occurred in 1960, which was described a few years later in Chile. Currently, S. aureus resistant to antistaphylococcal penicillins is endemic in Chilean hospitals and worldwide, being responsible for a high burden of morbidity and mortality. This resistance is mediated by the expression of a new transpeptidase, named PBP2a or PBP2', which possesses lower affinity for the β-lactam antibiotics, allowing the synthesis of peptidoglycan even in presence of these antimicrobial agents. This new enzyme is encoded by the mecA gene, itself embedded in a chromosomal cassette displaying a genomic island structure, of which there are several types and subtypes. Methicillin resistance is mainly regulated by an induction mechanism activated in the presence of β-lactams, through a membrane receptor and a repressor of the gene expression. Although mec-independent methicillin resistance mechanisms have been described, they are clearly infrequent.

SCCmec resistant mechanism, toxicity and prevalence in livestock-associate methicillin-resistant Staphylococcus aureus / 中国人兽共患病学报

Staphylococcus aureus is one of the most frequently encountered zoonotic pathogens.This bacterium produces the notable virulence factors such as hemolysin,panton-valentine leucocidin,exfoliative toxins and enterotoxin,which can cause invasive disease in humans and animals.Methicillin-resistant S.aureus (MRSA) is a multidrug-resistant bacterium which acquired the staphylococcal chromosome cassette mec (SCCmec).SCCmec is one of the key reasons for the antibiotic resistance of MRSA.As for MRSA resistance,the β-1actam resistance is mediated by mecA gene,and the drug-resistance genes inserted in the variable area of the SCCmec element play an important role in the multidrug resistance of MRSA.In recent years,it has been reported in Europe,North America and other countries that the multidrug resistance MRSA was detected in aquaculture environment and livestock.Besides,MRSA poses a serious threat to public health,and it can colonize and cause invasive disease in humans through aquaculture environment or other ways.This review summarizes drug resistance change of S.aureus and analysis of SCCmec resistance elements,toxicity and prevalence of livestock-associate MRSA,which would have theoretical and practical significance to understand S.aureus drug resistance,SCCmec typing,as well as control and prevent LA-MRSA transmission and infection between animals and humans.

Evaluation Of Hand Hygiene Training And Its Effect On Mdr Bacteria Detection In Various Intensive Care Units Of Era’S Lucknow Medical College

Hand hygiene is nowadays considered as one of the most important measures to prevent transmission and acquisition of HCAIs (health care associated infections). Monitoring hand hygiene compliance and providing healthcare workers with feedback regarding their performance are considered integral parts of a successful hand hygiene promotion programme. A total of 50 ICU staffs(resident doctors, faculty & nurses e.t.c.) were included in this interventional study. Baseline data of hand hygiene practices of all staffs and pre-intervention hand culture were obtained. Post intervention hand culture were taken after 30 days of training and interactive sessions as well as continous availability of ABHR in the ICU. Results of post-intervention hand culture showed a marked decrease in isolation of bacteria specially those of MRSAand ESBL. MRSAwas low by 35% and in non of the cases ESBL was reported. In all the ICUs frequency of hand hygiene was poor(average 31%) but improved significantly after intervention (70%).Introduction of ABHR was found to be an effective tool for improving hand hygiene. As a result of periodic training, monitoring, surveillance hand cultures and awareness generating campaign, transmission of resistant bacteria can be reduced, thus reducing the burden of nosocomial infection in a hospital set-up.

A multicenter study of targeted surveillance at Intensive Care Unit acquired MRSA infection in Tianjin district / 中华急诊医学杂志

Objective To study the incidence and risk factors of infection caused by methicillinresistant staphylococcus aureus (MRSA) with a targeted surveillance at intensive care unit (ICU) acquired MRSA infection in Tianjin area.Methods A prospective multi-center observational analysis of consecutive patients admitted to 15 adult ICUs from March 1,2012 through March 31,2014 was carried out.The ICUs were divided into four groups according to the type of the ICU.All of the patients were cared for with routine MRSA surveillance.A number of risk markers and prognostic factors were recorded.The risk factors contributing to ICU acquired MRSA were evaluated using a logistic regression model.Comparison of survival between groups was analyzed with Kaplan-Meier method.Results A total of 1 787 patients were enrolled,and 144 cases of them were MRSA infections.The patients with MRSA infection were significantly older than those with non-MRSA infection (P =0.043),length of ICU stay,length of antimicrobial therapy,the history of repeated administration of antibiotics in recent days,history of operation in the past five years,history of MRSA infection or colonization,frequent application of and the overall length of time for mechanical ventilation and central venous catheter and catheter-associated infection were significantly higher than those with non-MRSA infection.The survival rate of patients with non-MRSA infection were higher than those with MRSA infection (x2 =9.23,P =0.004).The rate of MRSA infection and MRSA colonization in 2013 were significantly lower than that in 2012,because the rate of hand hygiene rule execution and bacterial clearance rate were significantly higher in 2013.Multivariate Logistic regression analysis demonstrated that advanced age (OR =1.05,95％ CI:1.009-1.086),length of ICU stay (OR =1.05,95％ CI:1.01-1.08),history of MRSA infection or colonization (OR =1.33,95％ CI:1.82 -3.27),glucocorticoid therapy (OR =2.85,95％ CI:1.18-6.91),antacid medicine (OR =4.92,95％ CI:1.18-20.58),history of recent or repeated application of antibiotics (OR =3.26,95％ CI:1.06-4.59) catheter-associated infections (OR =2.22,95％ CI:1.08-4.59) were associated with ICU acquired MRSA infections.Conclusions Performing the rule of hand hygiene strictly as well as strengthening prevention and control of MRSA infections can effectively reduce the incidence of ICU acquired MRSA infections.The advanced age,length of ICU stay,history of MRSA infection or colonization,glucocorticoid therapy,antacids medicine,history of recent or repeated application of antibiotics,catheterassociated infections were independent risk factors of ICU acquired MRSA infections.

Inhibition mechanism of gallnut on biofilm formation by methicillin-resistant Staphylococcus aureus / 中国生化药物杂志

Objective To investigate the inhibition mechanism of gallnut on biofilm formation by MRSA 41577.Methods TTC assay was used to detect inhibitory effects of biofilms formation and mature biofilms.The of PIA on biofilm formation was studied using Congo red agar method.Micro-Ultraviolet Spectrophotometer was used to detect inhibitory effects of the release of eDNA.The influence for Baicalein on icaA and cidA gene expression were detected by RT-PCR method.Results The inhibitory concentration (MIC) and minimum bactericidal concentration (MIC) of MRSA 41577 BF were 0.5 mg/mL and 1 mg/mL, respectively.The inhibitory effect of galla on MRSA 41577BF formation and mature BF was significantly inhibited.Inhibition of MRSA 41577,the MIC and MBC of mature BF were 4 mg/mL and 16 mg/mL.Congo red test results show that Galla can inhibit the synthesis of MRSA 41577 PIA, and the concentration was dose-dependent.The results showed that gallnut could inhibit the release of MRSA 41577 eDNA, and the release amount of eDNA was 3.61μg/OD595 and 11.91μg/OD595 , respectively, when the concentration of gall was 1/2MIC.The release of eDNA was reduced by 69.7% (P<0.01).The expression of icaA and cidA genes in the control group was 9.7% and 6.67%, respectively.The expression of icaA and cidA in the control group was significantly lower than that in the control group ( icaA and cidA, and cidA gene expression were 100%, the expression of icaA and cidA genes were reduced by 90.3%and 93.3%, respectively (P<0.01).Conclusion The inhibitory effect of gallnut on the biofilm of MRSA 41577 is mainly through inhibiting the expression of icaA and cidA genes, and then affecting the synthesis of PIA and the secretion of eDNA .

Mechanism of Coriaria sinica extract on anti-methicillin resistant Staphylococcus aureus / 中草药

Objective: To explore the synergies mechanism of Coriaria sinica extract (CSE) combined with β-lactam antibiotics on methicillin resistant Staphylococcus aureus (MRSA). Methods: The relevant gene expression, autolytic enzyme, and influence of β-lactamase were determined by AFFX prokaryotic expression microarray, Western-blotting, SDS-PAGE gel electrophoresis, etc. Results: MRSA was resistant to the most antibiotics, and it had significant synergistic antibacterial effect while CSE was combined with β-lactam antibiotics (P < 0.05). The CSE can significantly reduce the total expression of RNA and regulate the expression of many genes with showing a dose-dependence when used alone or combined with ampicillin (AP), such as the basal metabolism genes, peptidoglycan hydrolase gene (lytM), transporter gene, PBPs, β-lactamase activity, etc. (P < 0.05). It can significantly improve the concentration of cefotaxime (CFX) in internal of MRSA (P < 0.05). Conclusion: The CSE has significant inhibitory effects on MRSA, and it has significant synergistic effects when combined with β-lactam antibiotic on MRSA. The mechanism is associated with many factors of MRSA, such as regulation of expression and transcription on target genes (ribA, PBPs, lytM, etc.), the influence of active efflux, autolysis and metabolism, etc.

High level of MRSA colonization in health care worker: alarm to implement health care policy.

The aim of the study was to investigate probable carrier rate of the healthcare workers and screened for carriers of MRSA as they could pose a potential risk factor for nosocomial transmission when the same carrier are exposed to the hospital setting during their clinical postings. A total of 100 nasal swabs were collected from the nursing staff and doctors. Sterile cotton swabs moistened with glucose broth were used for sample collection. Swabs were cultured on to nutrient agar, blood agar, and mannitol salt agar, incubated at 35 °C for 48 hrs. Staphylococcus aureus was identified by standard methods according to CLSI guidelines. Methicillin resistance was detected by using cefoxitin disc 30pgm on Mueller Hinton agar with 4% NaCL Of the 100 samples screened 30(30%) strains of Staphylococcus aureus were isolated, out of which 16 (53.33%) were Methicillin resistant Staphylococcus aureus (MRSA) and 14 (46.66%) were methicillin sensitive Staphylococcus aureus (MSSA). The overall carriage rate of methicillin resistant Staphylococcus aureus in our study was 16% with the highest rate being seen among the nursing staff (19.35%) and clinical staff carriage rate was lesser (10.52%) as compared to the nursing staff. Chest department samples showed higher carriage rate (33.33%) followed by pediatrics department (28.57%). The present study revealed that HCWs who have contact with patients are at risk of acquisition and colonization with antimicrobial resistant bacteria especially MRSA. Transient hand colonization is the primary mean of cross transmission. Simply education of HCWs on hygienic measures especially proper hand wash is the key to overcome MRSA infection in ICUs.

Prevalence and antimicrobial susceptibility pattern of methiciliin resistant Staphyllocococcus Aureus in tertiary care teaching hospital - Western India.

Background: Methicillin resistant Staphylococcus aureus (MRSA) infection traditionally has been associated with healthcare settings, colonizing patients with underlying debilitating health conditions. Now a day, Hospital management has become increasingly aware of issues related to MRSA infections in the patient population. Aims & Objective: To know the prevalence of MRSA amongst hospitalized as well as OPD based patients and to find out and compare the antibiotic resistance patterns of Methicillin resistant and Methicillin sensitive S. aureus. Material and Methods: Total of 534 Staphylococcus aureus isolated from various clinical specimens using the standard procedures during June 2010 to June 2011. Screening and confirmation of MRSA isolates were done by standard methods recommended by Clinical and Laboratory Standards Institute (CLSI). CDC definition was used to classify hospital and community Acquired Methicillin-Resistant Staphylococcus aureus. Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method. Detailed information regarding duration in hospital stay, ward, unit and clinical history were collected. Results: Out of 534 Staphylococcus aureus recovered from different clinical samples, 152 (28.46%) were found to be Methicillin resistant. 113 out of 152 isolates (74.34%) were Hospital acquired MRSA (HA-MRSA) while 39 out of 152 isolates (25.66%) were Community acquired MRSA (CA-MRSA). The antibiotic susceptibility result shows that MRSA isolates were resistant to multiple antibiotics than MSSA isolates. All isolated MRSA were sensitive to Vancomycin. Conclusion: Measures to control the emergence and spread of MRSA are needed to be improved because there are fewer options available for the treatment of MRSA infections. Thus, together with good professional practice and routine infection control precautions constitute the major measures in controlling and preventing MRSA.

Susceptibility Profile of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates to Antibiotics and Methanolic Extracts of Parkia biglobosa (Jacq) Benth.

Aims: To study the susceptibility profile of methicillin-resistant Staphylococcus aureus (MRSA) isolates from orthopaedic patients to antibiotics and methanolic extracts of Parkia biglobosa. Background: Antimicrobial resistance in Staphylococcus aureus has attained alarming proportions worldwide; with methicillin resistant Staphylococcus aureus (MRSA) becoming a major pathogen of public health importance associated with community and hospital acquired infections. Wound infections in orthopaedic patients with multidrug resistant pathogens significantly delay or prevent the union of fractured bones. The increasing prevalence of multidrug resistance in Staphylococcus aureus isolates calls for the search for alternative anti-staphylococcal agents. Methodology: Suspected staphylococcal isolates from wound, skin and bed swab samples from orthopaedic patients in a tertiary hospital in Zaria, Nigeria were characterized by established microbiological procedures and their antibiotic susceptibility pattern determined by the Kirby-Bauer-CLSI modified disc agar diffusion (DAD) technique. The activity of crude methanolic extract of the root, stem bark and leaf of Parkia biglobosa on the isolates determined. Results: A total of 179 isolates were confirmed S. aureus: wounds (24.6%), skin (39.1%) and bed (36.3%). The isolation rates for MRSA from the various sites were: wound (75%), skin (51.4%) and bed (73.8%). Antibiotic susceptibility testing revealed that the isolates were generally resistant to ampicillin (100% for all sites); ceftriazone (wound 69.7%, skin 72.2%, bed 70.8%); gentamicin (wound 54.5%, skin 52.8%, bed 37.5%) and ciprofloxacin (wound 51.5%, skin 47.2%, bed 35.4%). The phytochemical screening of the methanolic extract of the leaf, root and stem bark of Parkia biglobosa showed the presence of saponin, tannin, flavonoids and cardiac glycosides. The stem bark of Parkia biglobosa showed the greatest activity against all the multidrug resistant MRSA isolates at the 10mg/ml-25mg/ml concentration range used. In the search for alternative antistaphylococcal agents from natural sources, Parkia biglobosa will be a possible candidate for further investigation. Conclusion: There was high prevalence of multidrug resistant Staphylococcus aureus isolates from the clinical and surveillance samples from the orthopaedic patients.

Surgical site infections with special reference to methicillin resistant Staphylococcus aureus: experience from a tertiary care referral hospital in North India.

Objective: Surgical site infections are an important cause of health care associated infections among surgical patients. Aim: To determine the prevalence of Staphylococcus aureus and Methicillin resistant Staphylococcus aureus (MRSA) in surgical site infections with relation to age and sex and its antimicrobial susceptibility pattern. Methods: During a period of three years, 5,259 specimens received from surgical site infections were processed for isolation and identification of bacterial pathogens according to the standard microbiological techniques. Results: Abscess drainage was the most common type of surgical site infection (26.62%) and Staphylococcus aureus (34%) was the most common isolate. The most frequent isolation of the S. aureus in relation to age was noted in the age group of 21–40 years and the prevalence rate was higher in male patients. Out of the total S. aureus isolates, 27.96% were found to be methicillin resistant. Conclusions: There is a need for continuous surveillance and monitoring for the frequency of MRSA with its antimicrobial resistance patterns which may help in decreasing the prevalence of MRSA and antibiotic resistance.

Screening of methicillin resistant staphylococcus aureus in patients attending dental teaching Hospital.

Introduction : MRSA (Methicillin Resistant Staphylococcus aureus) is a major health care associated and community associated problem . Methicillin Resistant Staphylococcus aureus (MRSA) is one of the commensal organisms found in normal healthy individual’s anterior nares, throat and axilla. It is multi drug resistant organism and involved as one of the major cause of hospital acquired infections (HAI). Objectives : The present study was undertaken to know the prevalence of MRSA in patients attending dental Out Patient Department (OPD) in a teaching dental hospital. Material and methods : Total 100 patients were included with mean age 33.6 + 13.9, out of which 51 were female patients and 49 were male patients .Swabs collected from anterior nares and throat were plated on Mannitol Salt Agar which showed no growth for MRSA. Conclusion:Prevalance of MRSA in our Dental college is nil , so pre-requisite for screening MRSA before any dental procedure is not necessary.

Antibacterial constituents from roots of Zanthoxylum nitidum / 中草药

Objective: To isolate and identify the antibacterial constituents from the roots of Zanthoxylum nitidum. Methods: Bioassay-guided fractionation led to the isolation of compounds from the roots of Z. nitidum by using various chromatographic techniques such as silica gel, alumina, preparative TLC, and HPLC, and their chemical structures were then elucidated on the basis of spectroscopic data, including NMR, MS analysis, and their physicochemical properties. Results: Eleven compounds were isolated from the bioactive extracts in the roots of Z. nitidum and then were identified as skimmianine (1), oxychelerythrine (2), 8-methoxy-dihydrochelerythrine (3), β-sitosterol (4), L-sesamin (5), 8-methoxy-9-demethoxyldihydrochelerythrine (6), 4-hydroxy-N- methylproline (7), liriodenine (8), avicine (9), nitidine (10), and isobutyl benzoate (11), respectively. Compounds 1, 3, 6, 8, and 10 showed the potential inhibition on Staphylococcus aureus. Compound 8 showed the most potential inhibitory activity with MIC value of 31.3 μg/mL; Further studies demonstrated that compound 8 inhibited the clinical multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) activity with MIC value of 93.8 μg/mL, significantly. Conclusion: A series of bioactive alkaloids with the anti-staphylococcal activities were identified from the roots of Z. nitidum. Compounds 7, 9, and 11 are obtained from this plant for the first time, and the potential anti-staphylococcal activity of compound 8 against MRSA has been demonstrated, which has provided the chemical template as a new anti-bacterial agent against clinical multidrug-resistant MRSA infection.

Clinicobacteriological study of pyoderma with special reference to community acquired methicillin resistant staphylococcus aureus.

Background: Although prevalence of MRSA strains is reported to be increasing, there are scanty studies of their prevalence in community acquired pyoderma in western India. Aims: This study aimed at determining clinicobacteriological profile & prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) infections in community acquired pyoderma. Materials and methods: Prospective study was carried out in tertiary care hospital in Baroda.100 patients with pyoderma, visiting outpatient department of dermatology, were studied clinically and microbiologically. Sensitivity testing was done for gram positive & gram negative organisms by disc diffusion method. MRSA were detected by Agar dilution method. Result: Primary pyoderma accounts for 64% of cases with highest number of cases were of Impetigo (26%). The culture positive rate was 83% with Staphylococcus aureus being the major pathogen. (78.82%) Out of these 10.45% strains of Staphylococcus aureus were Methicillin Resistant Staphylococcus aureus. (MRSA) Conclusion: MRSA as a cause of pyoderma is a reality albeit in present study group. All the MRSA isolated were sensitive to Vancomycin. Sensitivity to Amoxyclav, Fluoroquinolones & Macrolides is quite good, which can be used for treatment.

Typing of Methicillin resistant Staphylococcus aureus: A technical review.

Increasing prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) worldwide is a growing public health concern. MRSA typing is an essential component of an effective surveillance system to describe epidemiological trends and infection control strategies. Current challenges for MRSA typing are focused on selecting the most appropriate technique in terms of efficiency, reliability, ease of performance and cost involved. This review summarises the available information on application, potential and problems of various typing techniques in discriminating the strains and understanding the epidemiology of MRSA strains. The phenotypic methods in general are easier to perform, easier to interpret, cost effective and are widely available, however less discriminatory. The genotypic methods are expensive and technically demanding, however more discriminatory. Newer technologies involving sequencing of various genes are coming up as broadly applicable and high throughput typing systems. Still there is no consensus regarding the single best method for typing of MRSA strains. Phage typing is recommended as first line approach in epidemiological investigation of MRSA strains. PFGE remains the gold standard for characterisation of outbreak strains. DNA sequencing methods including MLST, spa typing, SCCmec typing and toxin gene profile typing are more practical methods for detecting evolutionary changes and transmission events. The choice of typing technique further depends on the purpose of the study, the facilities available and the utility of data generated to answer a desirable research question. A need for harmonisation of typing techniques by following standard protocols is emphasised to establish surveillance networks and facilitate global MRSA control.