Strains Of Gram-positive Cocci Research Articles

Impact of Antibacterial Activity of Physical Storage Extracts on Pathogenic Bacteria

The overuse of antibiotics can lead to resistance among pathogenic bacteria. A new antibiotic that is effective against new and resistant bacterial strains is needed. Plants and marine organisms may offer such novel treatments. In this study, extracts of the seaweed U. lactuca, and the plant seeds N. sativa were tested against strains of Gram-positive cocci and Gram-negative bacilli S. aureus, and P. aeruginosa. The results of the bacterial inhibitor showed high activity in both extracts with inhibition of S. aureus growth up to 30 mm and 20 mm and P. aeruginosa growth inhibition was up to 12 mm and 15 mm, after the treated with 100 μl U. lactuca and N. sativa extracts, respectively. The MICs and MBCs were reflected with the growth inhibitor with values of 2 μl, 8 μl and 4 μl, 8 μl for S. aureus and P. aeruginosa after treated with N. sativa respectively. Kill-time increases as concentrations of U. lactuca and N. sativa extracts increase. Moreover, extracts stored in the transparent bottle decreased in effectiveness after one month of storage with percentage of 58.85%. After three months, heating the extracts of U. lactuca and N. sativa to 90°C increased their antibacterial activity.

Changing profile and increasing antimicrobial resistance of uropathogenic bacteria in Madagascar

ObjectivesWe wanted to update the distribution of community-acquired uropathogens and to estimate their susceptibility profile to newly available antibiotics in Antananarivo (Madagascar). Materials and methodsWe conducted a 3-year preliminary study (2011–2013) on bacteria isolated from the urine of patients at the Laboratory of Training and Research in Medical Biology (Antananarivo). ResultsThree hundred and fifty-seven pathogens were isolated: 234 (65.55%) Gram-negative bacilli and 123 (34.45%) Gram-positive cocci. The most commonly isolated bacteria were Escherichia coli (89 strains) followed by Staphylococcus aureus (48 strains). Thirty-three percent of Gram-negative bacilli were resistant to 3CG. Forty percent of Klebsiella pneumoniae strains were significantly resistant to imipenem (P=0.01). ConclusionsThe increased resistance to newly available antibiotics and the increased rate of Gram-positive cocci strains require a drastic surveillance of antibiotic resistance to ensure appropriate empirical treatment.

Analysis of pathogen distribution and drug resistance in coal workers' pneumoconiosis associated with pneumonia

To investigate the pathogen distribution and drug resistance in coal workers' pneumoconiosis associated with pneumonia and to provide a scientific basis for early guidance for rational clinical application of antibacterial agents. Seventy-six patients with coal workers' pneumoconiosis associated with pneumonia who were admitted to our hospital from June 2011 to June 2014 were enrolled as subjects. The sputum specimens were aseptically collected for bacterial culture and drug sensitivity tests. In 245 sputum specimens collected from 76 patients, a total of 218 strains of pathogens, including 163 strains of Gram-negative bacilli (74.77%), 39 strains of Gram-positive cocci (17.89%), and 16 strains of fungi (7.34%) were isolated by bacteriological tests. The main Gram-negative bacilli had high rates of resistance to amoxicillin/clavulanic acid, ampicillin, cotrimoxazole, cefotaxime, and aztreonam, and were sensitive to amikacin, imipenem, and meropenem. The main Gram-positive cocci had high rates of resistance to penicillin, erythromycin, amoxicillin/clavulanic acid, ampicillin, cefotaxime, and clindamycin, and were sensitive to vancomycin and teicoplanin. The main pathogens in these patients with coal workers' pneumoconiosis associated with pneumonia are Gram-negative bacilli, which are highly resistant to common clinically used antibacterial agents. The pathogen distribution and drug resistance should be well understood, and the antibacterial agents should be rationally selected according to the results of drug sensitivity tests.

In vitro resistance to daptomycin of staphylococcus aureus and enterococcus spp. strains

Abstract Daptomycin is the first antibiotic in a new class of cyclic lipopeptides, active in vitro against Gram - positive cocci. The mechanism of action is a rapid depolarization of the bacterial membrane potential, loss of cytoplasmic contents, mainly K+ ions and inhibition of protein, DNA and RNA synthesis, followed by the bacterial cell death. There were investigated 112 strains of Gram-positive cocci recommended for daptomycin susceptibility testing. Since the main clinical indications of daptomycin are the severe skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus, vancomicin-resistant enterococci and penicillinresistant Streptococcus spp, we tested daptomycin activity only in these species. The susceptibility tests was performed by Kirby- Bauer disc-diffusion method on Muller-Hinton agar supplemented with Ca 50 mg / ml. (CAMH - Ca 2 + ) as recommended by CLSI. During the period in which we conducted the study we isolated 112 strains of Gram-positive cocci, which we tested sensitivity to daptomycin. Resistance to Daptomycin of Staphylococcus aureus (4.11%) was lower than resistance to vancomycin (6.76%), but higher than the resistance to teicoplanin (2.71%) and linezolid (1.38%). In our study we did not identify daptomycin resistant strains of Enterococcus spp. In severe infections that require more aggressive treatment using active antibiotics on MRSA, daptomycin is a valid therapeutic option, but a susceptibility test is required to ensure effective indication. There were no daptomycin resistant Enterococcus spp. strains

Candidemia combined with bacterial bloodstream infection: analysis of clinical features and associated risk factors

To investigate the clinical characteristics of and risk factors for candidemia combined with bacterial bloodstream infection(BSI) by retrospective analysis of cases. The clinical data of cases diagnosed as candidemia combined with BSI confirmed by blood culture were compared with those of cases with mono-candidemia in Beiing Tongren Hospital from January 2009 to December 2011. A logistic regression analysis was performed to investigate the independent risk factors. Forty-two cases diagnosed as candidemia were analyzed including 14 cases of candidemia combined with BSI and 28 cases of mono-candidemia. Ten strains of gram-positive cocci and 4 strains of gram-negative bacilli were isolated from candidemia combined with BSI group.Six strains of C.albicans, 4 strains of C.glabrata, 3 strains of C.tropicalis and 1 strain of C.krosei were isolated. There was no C.parapsilosis isolated from candidemia combined with BSI group but 9 strains in the mono-candidemia group. The septic shock rate of the candidemia combined with BSI group was higher than that of the mono-candidemia group (12/14 vs 7/28, P = 0.000). The mortality rate of the candidemia combined with BSI group was higher than that of the mono-candidemia group (10/14 vs 15/28), but the difference did not reach statistical significance (P = 0.266).Four factors were found statistically different by univariate analysis, including hospitalization more than 4 weeks (P = 0.001), bacteremia before candidemia(P = 0.005), hematological tumor (P = 0.01) and abdominal infection (P = 0.001). Multivariate analysis showed that hospitalization more than 4 weeks was the independent risk factor. Gram-positive cocci were the predominant species and septic shock was more common in candidemia combined with BSI. Hospitalization more than 4 weeks was the independent risk factor for candidemia combined with BSI.

Bacterial isolates in traumatic globe ruptured patients in a peripheral tertiary medical college and hospital

Background: Ocular trauma can lead to access of bacteria to the intra ocular contents. So the information of the bacterial contaminants is crucial to institute empirical antibiotic therapy to prevent the development of endophthalmitis. Aims & Objectives: To isolate the bacterial contamination following traumatic globe ruptured patients in a peripheral tertiary medical college and hospital. Materials and Methods: This prospective study was conducted in the department of Ophthalmology, Burdwan Medical College, over a period of one year from April 2013- March 2014. A detailed history was taken and ophthalmological workup was done for each open globe injury cases. At the time of repair, we took three samples for bacteriological culture. Those samples were collected as conjunctival swab from inferior fornix, aqueous sample, and vitreous tap respectively. The collected samples were labeled properly and immediately sent to the department of microbiology for bacteriological culture and sensitivity. The culture report was studied and recorded. Results: The study included 75 cases, of which, 57were males, and 18 were females. Age of the study population was ranging from 18 – 54 years. Fifty seven (77.33%) study population belonged to rural areas, and eighteen (24%) were of urban area. Most common etiologic agent responsible for traumatic rupture of globe was stone chip followed by road traffic accident. Bacteria were isolated from 50 (66.66%) of the 75 eyes studied. Of these 50 eyes, a single isolate was detected in 39 (78%) eyes, while there were two isolates in 7 (14%) eyes, three and or more isolates in 4 (8%) eyes. In more detail, there were 33 strains of Gram-positive cocci, accounting for 66.0% of all isolates, of which most common was staphylococcus epidermidis (46%). Among 8 Gram-positive bacilli isolates (16%), all were of the genus Corynebacterium. There were 9 (18%) Gram-negative bacillary isolates, including 3 (6%) Escherichia coli; 2 (4%) isolates of Pseudomonas aeruginosa, and one isolate (2%) each of Proteus vulgaris, Enterobacter aerogenes, Klebsiella, and Haemophilus influenzae. Conclusion: Isolation of bacteria from eyes with open globe injuries, and their subsequent antibiotic sensitivity pattern, provides an insight into selection of appropriate prophylactic drugs for prevention of development of endophthalmitis.

A surveillance study of antimicrobial resistance of gram-positive cocci strains isolated from 16 teaching hospitals in China in 2012

Objective To investigate antimicrobial resistance among gram-positive cocci strains in China in 2012.Methods From June 2012 to December 2012,1790 consecutive and non-repetitive grampositive cocci strains were collected from 16 teaching hospitals.The minimal inhibitory concentrations (MICs) of antibacterial drugs were determined by agar dilution method.A retrospective study was conducted on the rates of resistance to antimicrobial agents.Data was analyzed using chi-square test.Results The prevalence of methicillin-resistant Staphylococcus aureus(MRSA) and methicillin-resistant coagulase-negative Staphylococci (MRCoNS) were 43.6％ (264/605) and 75.7％ (227/300),respectively.The prevalence of MRSA ranged from 20.5％ to 60.9％ in different regions.About 54.4％ (106/195) of Staphylococcus aureus from respiratory tract specimens,43.6％ (58/133) of Staphylococcus aureus from blood samples,and 29.8％ (56/188) of Staphylococcus aureus from wound and pus were resistant to methicillin.The prevalence of MRSA in elder patient group (53.9％,110/204) was higher than that in the younger adult patients (41.4％,149/360) (P＜0.05).The susceptible rates of MRSA to chloramphenicol and SXT were 92.4％(244/264) and 89.8％ (237/264),respectively.Susceptibility of MRSA to gentamycin,erythromycin,clindamycin,tetracyclines,rifampicin and quinolones were ranged from 12.5％ to 51.9％.One vancomycin-intermediate Staphylococcus aureus (VISA) was found in this study.All Staphylococci isolates were susceptible to teicoplanin,vancomycin,linezolid,daptomycin and tigecycline.The prevalence of penicillin-resistant Streptococcus pneumoniae (PRSP) in children below 3 years-old (61.2％,49/80) was higher than that in adult patients (40.2％,90/224) (P＜0.05).About 93.6％ (292/312) and 86.2％ (269/312) of S.pneumonia were resistant to erythromycin and clindamycin,respectively.Penicillin still showed a very high activity against Streptococcus spp.β-Hemolytic group,but more than 60％ of Streptococcus spp.β-hemolytic group were resistant to erythromycin,clindamycin and tetracyclines.Four vancomycin-resistant enterococcus (VRE) strains were found in this study.All Enterococcus isolates were susceptible to daptomycin and tigecycline,and 96.9％ (157/162) of E.faecalis and 99.3％ (150/151) of E.faecium were susceptible to line()dd.About 51.9％ (84/162) of E.faecalis and 61.6％ (93/151) of E.faecium were resistant to high concentration gentamycin.The susceptibility of E.faecalis to all antibiotics except chleramphenicol and tetracycline was higher than that of E.faecium.Conclusion The rates of antimicrobial resistance of Gram-positive cocci are different among strains isolated from different age groups or regions.Teicoplanin,vancomycin,linezolid,tigecycline and daptomycin showed very high activity against Gram-positive cocci. Key words: Antimicrobial resistance; Anti-bacterial drugs; Gram-positive cocci

Bacterial pneumonia as a result of mechanical ventilation in patients treated in intensive care units – epidemiological importance

Introduction. Ventilator-associated pneumonia (VAP) is among the most common hospital infections in an Intensive Care Unit (ICU). The most important risk factors of VAP are endotracheal catheterization and mechanical ventilation. Aim. The objective of the study was evaluation of the prevalence of ventilator-associated pneumonia, and determination of the type of microbiological agents in specimens collected from the bronchial tree. Material and methods. The study covered 42 patients: 59.5% of males and 40.5% of females, hospitalized in the Intensive Care Unit (ICU), in whom mechanical ventilation was applied. Airway secretion was grown on a solid agar medium: Columbia agar with 5% sheep blood, chocolate agar, McConkey and Sabouraud media. Identification of the bacterial strains grown was based on the determination of their biochemical properties, with the use of commercial assays (bio-Merieux): ID 32E and ID 32GN and tests ID 32 STAPH and API 20 STREP. Results. In the group of 42 patients who received mechanical ventilation (59.5% of the total number of hospitalized patients) VAP developed in 17 patients (40.5%). From the specimens 30 (34.9%) strains of Gram-negative rods, 19 (22%) strains of Gram-positive cocci, and 13 (15.1%) fungi were grown. The largest number of strains was isolated in patients who received artificial ventilation until day 20 of hospitalization. Conclusions. The microorganisms most often isolated from the upper airways were Gram-negative rods; patients admitted to ICU from other wards were colonized with bacterial flora conveyed with them from the original ward; the duration of artificial ventilation increases the risk of occurrence of ventilator-associated pneumonia.

Rising prevalence of antimicrobial resistance in urinary tract infections during pregnancy: necessity for exploring newer treatment options.

Background:Urinary tract infections (UTI) are one of the most common medical complications of pregnancy. The emergence of drug resistance and particularly the Extended-spectrum beta-lactamase production by Escherichia coli and methicillin resistance in Staphylococci, limits the choice of antimicrobials.Materials and Methods:Patients in different stages of pregnancy with or without symptoms of urinary tract infection attending the antenatal clinic of obstetrics and gynaecology were screened for significant bacteriuria, by standard loop method on 5% sheep blood agar and teepol lactose agar. Isolates were identified by using standard biochemical tests and antimicrobial susceptibility testing was done using Kirby Bauer disc diffusion method.Results:A total of 4290 (51.2%) urine samples from pregnant females showed growth on culture. Prevalence of asymptomatic bacteriuria 3210 (74.8%) was higher than symptomatic UTI 1080 (25.2%). Escherichia coli was the most common pathogen accounting for 1800 (41.9%) of the urinary isolates. Among the gram-positive cocci, coagulase negative species of Staphylococci 270 (6.4%) were the most common pathogen. Significantly high resistance was shown by the gram negative bacilli as well as gram positive cocci to the β-lactam group of antimicrobials, flouroquinolones and aminoglycosides. Most alarming was the presence of ESBL in 846 (47%) isolates of Escherichia coli and 344 (36.9%) isolates of Klebsiella pneumoniae, along with the presence of methicillin resistance in 41% of Staphylococcus species and high-level aminoglycoside resistance in 45(30%) isolates of Enterococcus species. Glycopeptides and carbepenems were the only group of drugs to which all the strains of gram positive cocci and gram negative bacilli were uniformly sensitive, respectively.Conclusions:Regular screening should be done for the presence of symptomatic or asymptomatic bacteriuria in pregnancy and specific guidelines should be issued for testing antimicrobial susceptibility with safe drugs in pregnant women so that these can be used for the treatment. For empirical treatment cefoperazone-sulbactum can be recommended, which is a safe drug, covering both gram positive and gram negative organisms and with a good sensitivity.

Recovery and screening for antibiotic susceptibility of potential bacterial pathogens from the oral cavity of shark species involved in attacks on humans in Recife, Brazil

The number of incidents involving sharks and humans at beaches in Recife, on the north-eastern Brazilian coast, is among the highest worldwide. In addition, wound infections in survivors are common; but the nature and risk of the aetiological agents is unknown. In the present study, 81 potential bacterial pathogens were identified in the oral cavity of sharks involved in attacks in Recife, and were subjected to antibiotic susceptibility tests using the standardized disc-diffusion method. The majority were enterobacteria such as Enterobacter spp., Citrobacter spp., Proteus spp., Providencia alcalifaciens, Escherichia coli, Moellerella wisconcensis and Leclercia adecarboxylata. Other Gram-negative bacteria included Vibrio spp., Burkholderia cepacia, Acinetobacter spp. and Pseudomonas spp. In addition, coagulase-positive and coagulase-negative Staphylococcus spp., Enterococcus spp. and Micrococcus spp. were identified, besides Streptococcus spp. from the viridans group. Resistance was especially found in the Proteus mirabilis and Citrobacter freundii, and ranged from 4 to 6 antibiotics out of the 13 tested. Gentamicin and vancomycin were the most effective against Gram-positive cocci strains, whereas levofloxacin was fully inhibitory against Gram-positive and Gram-negative bacteria. These data are discussed in light of a retrospective evaluation of the medical records of three shark victims treated at Restauração Hospital in Recife.

Clinical bacteriology and empiric therapy for hospital-acquired pneumonia in the elderly at a national leprosarium

Hospital-acquired pneumonia is one of the most important fatal respiratory diseases in the elderly. Prompt and precise empiric therapy is essential for recovery. Fourteen isolates from twelve elderly lepromatous leprosy patients (9 men, 3 women, mean age of 75.8 years) with hospital-acquired pneumonia were studied. Subsequently, empiric therapy with gentamicin and beta-lactams for nosocomial pneumonia in the elderly was examined. Fourteen types of bacteria isolated from expectorated sputum specimens consisted mainly of ten strains of gram-negative bacilli (71%) six of Klebsiella pneumoniae, one each of Citrobacter freundii, Enterobacter agglomerans, Serratia liquefaciens, and Aeromonas hydrophilia and four strains of gram-positive cocci (29%) two of Staphylococcus sp., one each of Streptococcus sp. and Streptococcus pneumoniae. Methicillin-resistant Staphylococcus aureus and Pseudomonas sp. were not detected. Resistance rates of the etiologic agents to the antibiotics showed that gentamicin was 7.7%, ceftazidime 0%, and cefmetazole 23.1%. Cephalosporins were superior to penicillins. As a result of empiric therapy, six elderly leprosy patients with nosocomial pneumonia were cured and one improved temporarily. This study shows the necessity of specific empiric therapy for hospital-acquired pneumonia in a hospital with many elderly patients. The combination of gentamicin and beta-lactams is of value as an initial antibiotic therapy for hospital-acquired pneumonia in the elderly.

Staphylococcus microti sp. nov., isolated from the common vole (Microtus arvalis)

Two strains of Gram-positive cocci were isolated from viscera of common voles (Microtus arvalis Pallas) with generalized Brucella microti infection in the Czech Republic. Biochemical features and phylogenetic analysis based on 16S rRNA gene sequences showed that the strains are representatives of the genus Staphylococcus and assigned Staphylococcus muscae as the nearest relative. A detailed characterization done by ribotyping, rpoB and hsp60 gene sequencing, whole-cell protein analysis and rep-PCR using the (GTG)(5) primer differentiated the two strains from all described staphylococci. DNA-DNA hybridization with the type strain of S. muscae demonstrated that the two strains should be considered as members of a novel species (26.8 % reassociation). The two analysed strains were found to be coagulase-negative, novobiocin-susceptible, oxidase-negative cultures, phenotypically close to one another, but showing differences in ribotype profiles. The major fatty acids were iso-C(15 : 0), iso-C(17 : 0), anteiso-C(15 : 0), C(18 : 2 )omega6,9c/anteiso-C(18 : 0), C(18 : 0) and C(18 : 1) omega9c. MK-7 was the predominant isoprenoid quinone, with minor amounts of MK-6 and MK-8. The polar lipid profile was composed of the major lipids diphosphatidylglycerol and phosphatidylglycerol and several unknown lipids. These results proved that the two isolates represent a novel staphylococcal species. The name proposed for this novel taxon is Staphylococcus microti sp. nov.; the type strain is 4005-LJ(m)(T) (=CCM 4903(T) =CCUG 55861(T) =DSM 22147(T)).

Evaluation of the automated system Vitek2 for identification and antimicrobial susceptibility testing of Brazilian Gram-positive cocci strains

Automated instruments offer many advantages for clinical laboratories. Nevertheless, they can have problems identifying and determining susceptibilities of some pathogens. Vitek2 (bioMérieux) is an automated system that was recently introduced to Brazil. We evaluated the performance of this equipment for Brazilian isolates that had been characterized using reference identification and antimicrobial susceptibility testing methods. Ninety-nine strains of Gram-positive cocci from a local reference center collection were analyzed, consisting of 50 coagulase-negative Staphylococcus (CoNS) and 49 Enterococcus and related species. Vitek2 correctly identified 79.8% (79/99) of the isolates. Oxacillin resistance was detected in 76% (19/25) of resistant S. epidermidis strains and in 88% (22/25) of other resistant CoNS species strains. Vancomycin resistance was detected in 100% (20/20) of resistant Enterococcus and related species strains. Vitek2 performed very well for the identification of S. epidermidis and non-epidermidis staphylococci, and for the detection of vancomycin resistance in Enterococcus and related species. However, the system needs improvement in order to provide reliable results for the characterization of some CoNS species, identification of Enterococcus and related species and for detecting oxacillin resistance in CoNS.

Evaluation of three different molecular markers for the detection of Staphylococcus aureus by polymerase chain reaction

The aim of this study was to target three genes of Staphylococcus aureus- fmhA (coding for a factor of unknown function), catalase and femA (coding for a factor essential for methicillin resistance) to establish and validate a PCR assay for the detection of this pathogen. Two pairs of primers were designed for fmhA and one pair each for catalase and femA genes. The PCR assays were standardized and found to give specific amplicons under similar reaction parameters. Target specificity of the primers was confirmed by DNA sequencing of the amplicons. While the initial inclusivity and exclusivity test reactions were in agreement in case of three of the primer pairs, one pair based on fmhA gene produced a non-specific product with a template DNA used in exclusivity test reactions. Forty-five strains of S. aureus were subjected to these PCR assays for their evaluation. Three among the four pairs of primers, one against each gene detected all the 45 strains precisely whereas one of the PCR assays using primers targeting the fmhA gene did not generate the specific amplicon with several of the strains. Seven unidentified strains of Gram-positive cocci subjected to these PCR assays produced negative results for each culture. Six of the strains were identified as Staphylococcus haemolyticus and one strain as Staphylococcus arlettae by 16S ribosomal gene analyses. All the three assay systems showed a detection limit of 100 cells per 20 μl reaction assay. For validation of these assay systems, 80 coded samples of 11% skimmed milk spiked with different pathogens were received from NICED (National Institute of Cholera and Enteric Diseases), Kolkata and subjected to these PCR assays. All the three assays could detect S. aureus correctly in two of the samples. Amongst 150 raw milk samples, 36 (24%) were found positive for S. aureus. We conclude that fmhA, catalase and femA genes are conserved in S. aureus and, therefore, could be used as specific targets for its detection and identification by PCR. The protocols developed herein could be used for rapid and specific detection of this pathogen in food, clinical and environmental samples, especially milk.

Mammalian defensins: structures and mechanism of antibiotic activity

Antibiotic peptides are important effector molecules in host-parasite interactions throughout the living world. In vertebrates, they function in first-line host defense by antagonizing a wide range of microbes including bacteria, fungi, and enveloped viruses. The antibiotic activity is thought to be based on their cationic, amphipathic nature, which enables the peptides to impair vital membrane functions. Molecular details for such activities have been elaborated with model membranes; however, there is increasing evidence that these models may not reflect the complex processes involved in the killing of microbes. For example, the overall killing activity of the bacterial peptide antibiotic nisin is composed of independent activities such as the formation of target-mediated pores, inhibition of cell-wall biosynthesis, formation of nontargeted pores, and induction of autolysis. We studied the molecular modes of action of human defense peptides and tried to determine whether they impair membrane functions primarily and whether additional antibiotic activities may be found. We compared killing kinetics, solute efflux kinetics, membrane-depolarization assays, and macromolecular biosynthesis assays and used several strains of Gram-positive cocci as test strains. We found that membrane depolarization contributes to rapid killing of a significant fraction of target cells within a bacterial culture. However, substantial subpopulations appear to survive the primary effects on the membrane. Depending on individual strains and species and peptide concentrations, such subpopulations may resume growth or be killed through additional activities of the peptides. Such activities can include the activation of cell-wall lytic enzymes, which appears of particular importance for killing of staphylococcal strains.

Surveillance of bacterial resistance in Shandong Province

目的 探讨山东省医院临床分离菌株对抗菌药物的耐药情况.方法 2001年12月～2002年12月收集本省10城市12家医院临床分离菌1 441株,其中革兰阳性球菌383株,占分离菌的26.58%;革兰阴性杆菌1 058株,占分离菌的73.42%.采用标准平板2倍稀释法,测定抗菌药物对细菌的最低抑菌浓度(MIC),按照美国临床实验室标准化委员会2001年版标准,计算MIC50、MIC90,判断敏感率(S%)、中介率(I%)、耐药率(R%).结果耐苯唑西林金黄色葡萄球菌(MRSA)检出率为32.4%,耐苯唑西林的表皮葡萄球菌(MRSE)检出率为91.3%.肺炎链球菌耐药率(R+I)为11.2%,其中R为5.6%,I为5.6%.粪肠球菌对氨苄西林的R%为16.8%,屎肠球菌对氨苄西林的R%为62.5%.粪肠球菌对万古霉素和去甲万古霉素I%均为1.1%,对屎肠球菌中介率均为6.3%.本研究未发现糖肽类耐药的金黄色葡萄球菌(GRSA)和表皮葡萄球菌(GRSE).未发现万古霉素耐药的肠球菌(VRE).绿脓假单胞菌对抗菌药物的耐药率(R+I)依次为头孢哌酮/舒巴坦(19.1%)＜头孢他啶(20.0%)＜哌拉西林/他唑巴坦(22.3%)＜头孢吡肟(27.4%)＜左氧氟沙星(27.9%).大肠埃希菌、肺炎克雷伯菌产超广谱β内酰胺酶比率分别为19.6%、23.2%.结论山东地区的常见耐药菌MRSA、MRSE、PRSP、氨苄西林耐药肠球菌的耐药率与国内报道水平接近或低于国内报道水平;肠杆菌产超广谱β内酰胺酶的比率略低于国内报道。

Burkholderia is highly resistant to human Beta-defensin 3.

The bactericidal activity of the novel beta-defensin hBD-3 against 28 species and 55 strains of gram-positive cocci and gram-negative fermentative and nonfermentative rods was tested. All strains proved to be highly or intermediately susceptible to hBD-3 (minimal bactericidal concentration [MBC], </=50 micro g/ml), except for Burkholderia cepacia, for all 23 tested strains of which MBCs were >100 micro g/ml.

Un Aggiornato Profilo di Sicurezza della Moxifloxacina

The study was initiated to determine the in vitro activity and MIC/disk test comparisons of BMS284756, a new des-fluoro(6)-quinolone, against isolates of staphylococci and enterococci from the SENTRY Antimicrobial Surveillance Program, 2000. Isolates were tested by reference broth microdilution and standardized disk diffusion methods. Against 3,789 strains of gram-positive cocci from the SENTRY Program (2000), the BMS284756 MIC90 and percentage susceptible at < or = 2 and < or = 4 microg/ml were: Staphylococcus aureus (4 microg/ml; 89.3 and 97.1%), coagulase-negative staphylococci (CoNS; 4 microg/ml; 86.1 and 96.0%) and enterococci (> 4 microg/ml; 62.0 and 76.2%). Also tested were selected staphylococci (300 strains) and enterococci (102 strains) by two standardized methods. The activity of BMS284756 was highly correlated with oxacillin resistance among staphylococci. Oxacillin-susceptible staphylococci were all inhibited by BMS284756 at < or = 0.5 microg/ml, whereas oxacillin-resistant strains required inhibitory concentrations of > or = 1 microg/ml. Excellent correlation was observed between the MIC and 5-microg disk zone diameter for staphylococci and enterococci (r=0.91 to 0.93). Among vancomycin-susceptible enterococci, 67% of Enterococcus faecalis, 25% of E. faecium, and 76% of other Enterococcus spp. isolates were inhibited by BMS284756 at < or = 2 microg/ml. All vancomycin-resistant enterococci (VRE; 11 E. faecalis and 15 E. faecium) were inhibited by > or = 2 microg/ml of BMS284756. Among the non-VRE, non-faecium enterococcal isolates (n=64), 62% were inhibited by < or = 0.5 microg/ml. BMS284756 showed excellent activity against oxacillin-susceptible staphylococci and moderate activity against enterococci other than VRE and E. faecium. Acceptable correlations were observed between MIC and disk test results for both tested genus groups.

Pharmacodynamics and pharmacokinetics of spiramycin and their clinical significance.

The absolute bioavailability of oral spiramycin is generally within the range of 30 to 40%. After a 1 g oral dose, the maximum serum drug concentration was found to be within the range 0.4 to 1.4 mg/L. The tissue distribution of spiramycin is extensive. The volume of distribution is in excess of 300 L, and concentrations achieved in bone, muscle, respiratory tract and saliva exceed those found in serum. The intracellular penetration of spiramycin is also rapid and extensive, with the concentrations in alveolar macrophages 10 to 20 times greater than simultaneous serum concentrations. Spiramycin is less metabolised than some of the other macrolides. The renal excretion of spiramycin is low, with 4 to 20% of the dose being excreted by this route. High concentrations of spiramycin are achieved in bile, which is an important route of elimination. The serum elimination half-life of spiramycin is between 6.2 and 7.7 hours. Of significance to clinicians may be the finding that spiramycin is highly concentrated in the respiratory tract and other tissues and macrophages. The post-antibiotic effect of spiramycin is significant and this effect is more prolonged than that of erythromycin against Staphylococcus aureus. Spiramycin has also been shown to greatly reduce the capacity of strains of Gram-positive cocci to adhere to human buccal cells.

Phenotypic and genotypic characterization of atypical Lactococcus garvieae strains isolated from water buffalos with subclinical mastitis and confirmation of L. garvieae as a senior subjective synonym of Enterococcus seriolicida.

During a survey of bacterial agents that cause subclinical mastitis in water buffalos, we isolated several strains of gram-positive cocci that appeared to be enterococci except that they grew very slowly at 45 degrees C and grew slowly in broth containing 6.5% NaCl. On the basis of the results of conventional physiologic tests, these strains were identified as Enterococcus durans. However, none of the strains reacted with the AccuProbe Enterococcus genetic probe. The whole-cell protein profiles of these organisms were compared with the profiles of Enterococcus and Lactococcus reference strains. apart from minor quantitative differences, the mastitis isolates had indistinguishable protein profiles that were similar to the profiles of the Lactococcus garvieae and Enterococcus seriolicida type strains. The results of DNA relatedness studies performed by using the hydroxyapatite method at 55 and 70 degrees C indicated that all of the mastitis isolates were related to the type strain of L. garvieae at the species level, despite the fact that they exhibited several uncommon phenotypic characteristics (growth at 45 degrees C, growth in broth containing 6.5% NaCl, and failure to produce acid from mannitol and sucrose). The high levels of DNA relatedness between strains of L. garvieae is a senior synonym of E. seriolicida, L. garvieae should be retained as the species name and strain ATCC 43921 should remain the type strain of this species.