The production of extracellular vesicles is a ubiquitous process in both Gram-negative and Gram-positive bacteria. Gram-negative bacteria produce and secrete outer membrane vesicles during in vitro culture and in vivo infection and their contribution to bacterial pathogenesis has been well characterized. However, little is known about extracellular vesicles in Gram-positive bacteria. Until now, only few Gram-positive bacterial species, Staphylococcus aureus, Bacillus anthracis, B. cereus, and B. subtilis, have been found to produce membrane vesicles (MVs), but their contribution to bacterial pathogenesis has not been understood. Here, I discuss S. aureus MVs in terms of MV production, interaction of MVs with host cells, and immune response against MVs to understand its potential role in S. aureus pathogenesis.
Bacillus anthracis ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Membranes ; Proteome ; Staphylococcus ; Staphylococcus aureus

Contamination with sanitary microorganisms from Enterobacteriaceae, Pseudomonadaceae, Staphylococcaceae, Micrococcaceae and Bacillaceae families in flower bee pollen from Bulgaria after one-year vacuum-packed cold storage has been found. Dried flower bee pollens intended for human consumption were with high incidence rate of contamination with Pantoea sp. (P. agglomerans and P. agglomerans bgp6) (100%), Citrobacter freundii (47%), Proteus mirabilis (31.6%), Serratia odorifera (15.8%) and Proteus vulgaris (5.3%). Bee pollens were also positive for the culture of microorganisms from Staphylococcaceae, Micrococcaceae and Bacillaceae families: Staphylococcus hominis subsp hominis, Staphylococcus epidermidis, Arthrobacter globiformis, Bacillus pumilis, Bacillus subtilis and Bacillus amyloliquefaciens. It was concluded that, if consumed directly, the vacuum-packed cold stored dried bee pollen, harvested according hygienic requirements from bee hives in industrial pollution-free areas without intensive crop production, is not problem for healthy human.
Arthrobacter ; Bacillaceae ; Bacillus ; Bacillus subtilis ; Bees* ; Bulgaria ; Citrobacter freundii ; Crop Production ; Enterobacteriaceae ; Flowers* ; Humans ; Incidence ; Micrococcaceae ; Pantoea ; Pollen* ; Proteus mirabilis ; Proteus vulgaris ; Pseudomonadaceae ; Serratia ; Staphylococcaceae ; Staphylococcus epidermidis ; Staphylococcus hominis ; Urticaria ; Vacuum*

We compared the activities of tedizolid to those of linezolid and other commonly used antimicrobial agents against gram-positive cocci recovered from patients with skin and skin structure infections (SSSIs) and hospital-acquired pneumonia (HAP) in Korean hospitals. Gram-positive isolates were collected from 356 patients with SSSIs and 144 patients with HAP at eight hospitals in Korea from 2011 to 2014. SSSIs included impetigo, cellulitis, erysipelas, furuncles, abscesses, and infected burns. Antimicrobial susceptibility was tested by using the CLSI agar dilution method. All of the gram-positive isolates were inhibited by < or =1 microg/mL tedizolid. The minimum inhibitory concentration [MIC]90 of tedizolid was 0.5 microg/mL for methicillin-resistant Staphylococcus aureus, which was 4-fold lower than that of linezolid. Tedizolid may become a useful option for the treatment of SSSIs and HAP caused by gram-positive bacteria.
Abscess ; Agar ; Anti-Infective Agents ; Burns ; Cellulitis ; Erysipelas ; Furunculosis ; Gram-Positive Bacteria* ; Gram-Positive Cocci ; Humans ; Impetigo ; Korea ; Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Pneumonia* ; Skin*

Antibacterial activity of EA, a preparation of water soluble components made from carpophores of Elfvingia applanata (Pers.) Karst, was examined by macrobroth diltution method against a number of bacterial species. Antibacterial effects of EA were expressed as minimal inhibitory concentration (MIC) for growth. Among twelve species of bacteria tested, six strains of each gram positive bacteria and gram negative bacteria, EA showed the most potent antibacterial activity against Staphylococcus epidermidis and Proteus vulgaris, of which MICs were 1.25 mg/ml of EA. To investigate the antibacterial effects of combinations of EA with third generation cepholosporins, such as cefotaxime, ceftriaxone, ceftazidime, and cefixime, the fractional inhibitory concentration (FIC) and fractional inhibitory concentration index (FICI) were determined by macrodilution checkerboard assay for twelve bacterial strains. Combinations of EA and third generation cephalosporins exhibited either additive or indifferent effects in most instances. However, synergistic effects were observed in six instances. No antagonistic effect was observed in any cases.
Bacteria ; Cefixime ; Cefotaxime ; Ceftazidime ; Ceftriaxone ; Cephalosporins* ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Proteus vulgaris ; Staphylococcus epidermidis

The antimicrobial agents reduced infectious diseases significantly. However, antibiotic resistance has followed for almost every antimicrobial agent. Especially, Staphylococcus aureus was one of the most notorious for the multidrug resistance. Streptomyces sp. 681 has been selected for antibiotic-producing strain against methicillin-resistant Staphylococcus aureus (MRSA) from 1,000 strains of Actinomycetales which had been isolated from soil. In antimicrobial susceptibility test, all of the test strains were susceptible to vancomycin. However, most strains of Staphylococcus aureus were found to be resistant to methicillin. Ninety eight (75%) strains out of 129 strains showed multiple resistance pattern to more than 5 antimicrobial agents. The MIC values of the purified antibiotic (K-681) were 1-32 ug/ml against Gram-positive bacteria compared to >128 ug/ml against Grarn-negative bacteria or fungi. The MIC was 8 ug/ml for 90% of the 129 clinical isolates of S. aureus. The antibiotic showed no cytotoxicity against P 388, HeLa, and S180 at the concentration of 500 ug/ml.
Actinomycetales ; Anti-Infective Agents ; Bacteria ; Communicable Diseases ; Drug Resistance, Microbial ; Drug Resistance, Multiple ; Fungi ; Gram-Positive Bacteria ; Methicillin ; Methicillin-Resistant Staphylococcus aureus ; Soil ; Staphylococcus aureus* ; Staphylococcus* ; Streptomyces* ; Vancomycin

BACKGROUND: Local epidemiologic data on prevalent pathogens are important to guide empirical antibiotic therapy. In this study, we observed annual changes in frequency of occurrence and in vitro antimicrobial susceptibility of blood isolates over a period of 13 years. MATERIALS AND METHODS: We reviewed blood isolates identified during the period from 1998 to 2010 at Seoul National University Hospital. Only first isolates for each patient were included in the analysis. We analyzed the frequency of isolates and their trend with regard to in vitro antimicrobial susceptibility. Data were presented according to guidelines of the Clinical and Laboratory Standards Institute (CLSI) (2009). RESULTS: A total of 23,501 isolates were identified during the period from 1998 to 2010. Fifty-five percent of the isolates were gram-positive cocci, 38% were gram-negative rods, and 3% were fungi. Coagulase-negative Staphylococcus (CoNS) (24%), Escherichia coli (16%), Staphylococcus aureus (10%), and Klebsiella pneumoniae (8%) were the most commonly isolated bacteria, and Candida albicans (2%) was the most commonly isolated fungus. The frequency of CoNS increased from 18.0% to 26.8%, whereas the frequency of E. coli and K. pneumoniae decreased from 20.2% to 13.7% and from 11.7% to 6.7%, respectively. Overall, the proportion of methicillin-resistant S. aureus changed from 47.9% to 62.1%. In E. coli, the resistance rate of cefotaxime and ciprofloxacin increased over a period of 13 years. However, such an increase of resistance was not observed in K. pneumoniae. In P. aeruginosa, and particularly in A. baumannii, resistance to imipenem rose alarmingly (3% in 1998 to 27.8% in 2010, 5% in 1998 to 68.9% in 2010, respectively). CONCLUSIONS: Over the last 13 years, the proportion of CoNS in blood isolates increased, which led to a relative decrease of isolated gram-negative rods. Proportions of MRSA showed no significant change, whereas cefotaxime resistant and ciprofloxacin resistant E. coli increased. Imipenem resistant P. aeruginosa and A. baumannii also increased during the study period.
Bacteremia ; Bacteria ; Candida albicans ; Cefotaxime ; Ciprofloxacin ; Escherichia coli ; Fungi ; Gram-Positive Cocci ; Humans ; Imipenem ; Klebsiella pneumoniae ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus ; Pneumonia ; Republic of Korea ; Staphylococcus ; Staphylococcus aureus

BACKGROUND: Although most of aerobic gram-positive bacilli have been considered to be contaminants, gram-positive bacilli should be identified to the species level if they are isolated from sterile body sites such as blood, and from adequately collected clinical specimens if they are the predominant organisms. However, identification of gram-positive bacilli are difficult due to the enormous diversity of these organisms and the small number of readily available commercial identification systems in clinical laboratories. Gram-positive bacilli and coccorods isolated from blood cultures were tested with BBL Crystal Gram-Positive (GP) Identification (ID) system in order to evaluate the system's usefulness of identifying these bacteria. METHODS: Thirty-seven stock strains of aerobic gram-positive bacteria isolated from blood cultures between October 1998 and November 1999 at Wonju Christian Hospital were simultaneously tested by BBL Crystal GP ID system and API system. Three kinds of API system (API Coryne, API 50 CHB, and API 20 Strep) were tested according to gram stain results. Gram-positive bacilli or gram-positive coccorods consecutively isolated from blood cultures from May to November in 2000 were identified by BBL Crystal GP ID system. RESULTS: Among the 37 stock strains of aerobic gram-positive bacteria, agreement rate of identification between Crystal GP ID system and API system were 88% to the genus level and 63% to the species level in Bacillus species, and 90% to the genus level in Corynebacterium species. The isolation rate of gram-positive bacteria from blood cultures from May to November in 2000 to the genus level were: Bacillus; 41.9%(18/43), Corynebacterium; 37.2%(16/43), and the other grampositive coccorods; 20.9%(9/43). CONCLUSIONS: Crystal GP ID system is a useful identification system which, when combined with basic microbiological tests, should lead to satisfactory identification results for gram-positive bacteria isolated from blood cultures.
Bacillus ; Bacteria ; Corynebacterium ; Gangwon-do ; Gram-Positive Bacteria*

PURPOSE: By identifying micro-organism in postoperative patients, we evaluated problems associated with the use of cephalosporin for the prevention of infection, and antibiotic choice in cases, in which causative micro-organisms cannot be islolated. MATERIALS AND METHODS: Eighteen patients, from January 1998 to May 2002, who received arthroplasty, were studied. All cases were administered preoperative first generation cephalosporin one hour before operation. All patients with infection had micro-organisms identified received an antibiotic sensitivity test. RESULTS: Gram positive cocci were identified in fifteen cases (83%) (staphylococcus was the most common (72%)), and there were eight cases (80%) in acute infections and seven (88%) in chronic. 78-83% were sensitive to vancomycin, teicoplanin and ciprofloxacin, but only 17% were sensitive to cephalothin. CONCLUSION: Staphylococcus was found to be the most common organism in postoperative infection, and ciprofloxacin was more effective than cephalosporin. Ciprofloxacin is considered to be an effective antibiotic in patients with unidentified causative organisms.
Arthroplasty ; Bacteria* ; Cephalothin ; Ciprofloxacin ; Gram-Positive Cocci ; Humans ; Staphylococcus ; Teicoplanin ; Vancomycin

The global emergence and spread of multidrug resistant bacterial infections in communities and hospitals has become an important issue in public health. The resistance rate of gram-positive cocci to vancomycin and the resistance rate of several gram-negative bacilli against cefotaxime and carbapenem have been continuously increasing. Surveillance of antimicrobial resistance is essential for providing information on the magnitude of and trend in multidrug resistance. Therefore, beginning 2011, more robust and effective management is to be legally required for six multidrug-resistant bacteria that have been linked to healthcare-related infections: vancomycin-resistant Staphylococcus aureus (VRSA), vancomycin-resistant enterococci (VRE), methicillin-resistant S. aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MRPA), multidrug-resistant Acinetobacter baumannii (MRAB), and carbapenem-resistant Enterobactericeae (CRE). We have also performed laboratory-based sentinel surveillance for VRSA/VISA since 2002 and carbapenemase-producing Enterobacteriaceae since November, 2010. This article reviews the national surveillance programs, and molecular epidemiology of multidrug-resistant bacteria.
Acinetobacter baumannii ; Bacteria ; Bacterial Infections ; Cefotaxime ; Drug Resistance, Multiple ; Enterobacteriaceae ; Gram-Positive Cocci ; Methicillin Resistance ; Molecular Epidemiology ; Nitriles ; Pseudomonas aeruginosa ; Public Health ; Pyrethrins ; Sentinel Surveillance ; Staphylococcus aureus ; Vancomycin

Vancomycin is an anti biotic produced by Streptomyces orientalis and is primarily active against gram-positive bacteria, especially against methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. It has been increasingly recommended for intravitreal injection on behalf of conventional therapy in bacterial endophthalmitis caused by gram-positive organisms due to increasing resistance to the cefazolin. Authors evaluated the retinal toxic reaction after vitrectomy with infravitreal infusion containing various doses of vancomycin between 1 microgram/ml to 500 microgram/ml into 20 rabbit eyes to determine the safe dose of vancomycin. The histologic features of the rabbit eyes treated with 20 microgram/ml or more showed toxic reactions including hypertrophy of retinal pigment epithelium, disorganization and loss of the photoreceptor cells and accummulation of inflammatory cells in subretinal space. These results suggest that intravitreal infuion of vancomycin in a dose of 10 microgram/ml or less appears to have no retinal toxicity in the rabbit model.
Cefazolin ; Endophthalmitis ; Gram-Positive Bacteria ; Hypertrophy ; Intravitreal Injections ; Methicillin-Resistant Staphylococcus aureus ; Photoreceptor Cells ; Retinal Pigment Epithelium ; Retinaldehyde* ; Staphylococcus epidermidis ; Streptomyces ; Vancomycin* ; Vitrectomy