呼吸内科下呼吸道感染细菌分布及其耐药性分析

目的探析呼吸内科下呼吸道感染细菌分布及其耐药性。方法选择湖北省孝感市中心医院呼吸内科收治1 537例下呼吸道感染患者,行痰液培养明确细菌分布并进行药敏试验掌握抗菌药物耐药情况。结果 1 537例患者共得到672份(43.72%)阳性标本,所获得菌株共782例,其中546例(69.82%)为革兰阴性球菌、157(20.08%)为革兰阳性球菌、79例(10.10%)为真菌。金黄色葡萄球菌、表皮葡萄球菌、肺炎链球菌主要对万古霉素、呋喃妥因、亚胺培南等有较高耐药性。结论革兰阴性球菌为下呼吸道感染最常见病原菌,包括铜绿假单胞菌、鲍式不动杆菌等,耐药分析显示金黄色葡萄球菌、表皮葡萄球菌、肺炎链球菌主要对万古霉素、呋喃妥因、亚胺培南、左氧氟沙星等耐药性高,临床用药时需予以注意。     

A new method of synthesis and antibacterial activity evaluation of piper amides

Several natural piper amides and their mimics were synthesized by developing a new strategy of amide formation. The piper amides were tested against both gram +ve and gram -ve bacterial strains and found that they are particularly more active against Staphylococcus aureus and Chromobacterium violaceum strains.     

Facile preparation of antibacterial polymer coatings via thiol-yne click photopolymerization

Novel antibacterial polymer coatings were prepared by a facile thiol-yne click photopolymerization of 1-propargyl-3-alkyl-1,3-diazanyl-2,4-cyclopentadiene bromide ([PAIM]Br) and tetra(3-mercapto-propionate) pentaerythritol (PETMP) (2:1 molar ratio) using 2,2-dimethoxy-2-phenylacetophenone (DMPA) as initiator. The antibacterial activity of the coatings was tested against Staphylococcus aureus (ATCC 292130) and Escherichia coli (ATCC 25922) by the dynamic shake method. The evaluation results revealed the antibacterial polymer coatings exhibited excellent inhibitory activity against S. aureus and E. coli, especially for S. aureus.     

Regioselective synthesis and antimicrobial evaluation of some thioether–amide linked 1,4-disubstituted 1,2,3-triazoles

A series of 1,4-disubstituted 1,2,3-triazoles having thioether as well as amide linkage were synthesized from aryl(prop-2-yn-1-yl)sulfanes and 2-azido-N-substituted acetamides through Cu(I) catalyzed click reaction. Structures of newly synthesized compounds (3a–3x) were confirmed by spectral techniques like FTIR, ¹H NMR, ¹³C NMR, and HRMS. The synthesized triazoles were evaluated for in vitro antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Candida albicans, and Aspergillus niger. Compounds 3m and 3q displayed appreciable broad spectrum antimicrobial activity against tested microbial strains. The nanoformulations of compounds 3m and 3q were also prepared and examined against one bacterial strain and one fungal strain.     

金黄色葡萄球菌及其甲氧苯青霉素耐药性的MALDI-TOF MS鉴定

用MALDI－TOS MS细菌指纹图谱鉴定细菌，建立区分金黄色葡萄球菌甲氧苯青霉素耐药株和敏感株的MALDI－TOF MS分析方法，检测了76株从临床标本中分离得到的金黄色葡萄球菌，用软件进行聚类分析，以nuc(耐热核酸酶）基因和mecA(耐药）基因聚合酶链反应（PCR）检测结果为参照，74％的菌株经MALDI－TOF MS给出了正确的鉴定结果；金黄色葡萄球菌甲氧苯青霉素耐药株和敏感株的质谱图有很大差别，各自有其特征峰；经过软件聚类分析，76株实验菌株划敏感群和耐药群；与PCR检测结果对照，有7株菌PCR检测mecA基因为阴性，而经MALDI－TOF MS鉴定为耐药株，表型鉴定表明其中有5株为敏感株；利用细菌指纹图谱和数据库检索对大多数菌株实现了正确鉴定；MALDI－TOF MS分辨率高，甚至可以区分株间的差异，实现了区分金黄色葡萄球菌甲氧苯青霉素耐药株和敏感株；结果表明MALDI－TOF MS提供了一个很有前景的鉴定细菌的快速方法。     

In vivo effects of porphyrins on bacterial DNA.

The DNA damage in intact Staphylococcus aureus and E. coli cells induced by photosensitized deuteroporphyrin or hemin is described. Treatment of S. aureus cultures with hemin or photosensitized deuteroporphyrin (Dp) caused time-dependent changes in the plasmidial DNA profiles. The major observation was the disappearance of the plasmid supercoiled fraction. The chromosomal DNA was also affected by hemin and by photosensitized Dp, since its degradation products were detected after exposing the bacterial cells to the porphyrin drugs. Photosensitization of E. coli cells, pretreated with Dp and polymyxin B nonapeptide (PMBNP), also resulted in plasmidial damage. No such damage occurred when E. coli cultures were treated with hemin and PMBNP. The above results can be tightly correlated with the antimicrobial action of porphyrins. Their damage to the bacterial DNA seems to reflect one of the in vivo effects of these porphyrins.     

A simple structural-based approach to prevent aminoglycoside inactivation by bacterial defense proteins. Conformational restriction provides effective protection against neomycin-B nucleotidylation by ANT4

Herein, we describe how the conformational differences exhibited by aminoglycosides in the binding pockets of the ribosome and those enzymes involved in bacterial resistance can be exploited in the design of new antibiotic derivatives with improved activity in resistant strains. The simple modification shown in the figure, leading to the conformationally restricted 5, provides an effective protection against aminoglycoside inactivation by Staphylococcus aureus ANT4, both in vivo and in vitro.     

A Biosurfactant‐Inspired Heptapeptide with Improved Specificity to Kill MRSA

The emergence and rapid spread of methicillin‐resistant Staphylococcus aureus (MRSA) poses a serious threat to public health. New antibiotics and strategies are urgently needed to combat S. aureus associated infections. Bacaucin, a novel cyclic lipopeptide from Bacillus subtilis CAU21, is reported. Bacaucin shows broad antibacterial activity against Gram‐positive bacteria, but is also hemolytic and cytotoxic. However, bacaucin‐1, a bacaucin‐inspired ring‐opened heptapeptide, shows specific antibacterial activity against MRSA by a membrane‐disruptive mechanism without detectable toxicity to mammalian cells or induction of bacterial resistance. Bacaucin‐1 was efficient in preventing infections in both in vitro and in vivo models and is a valuable prototype antibiotic with high potential against S. aureus infections.     

Synthesis of novel azo Schiff bases and their antibacterial and antifungal activities

Ten new azo Schiff bases 5a-h and 7a-b were prepared in excellent yields via the condensation of different aromatic amines and a new azoaldehyde, 2-hydroxy-3- methoxy-5-(4-methoxyphenylazo)benzaldehyde (4) by two different methods. All new compounds were tested against five microorganisms: Staphylococcus aureus (Gram positive and methicillin resistant), Bacillus subtilis (Gram positive), Kelebsiella pneumonia, Pseudomonas aeruginosa and Escherichia coli (all Gram negative). Compounds 4, 5a, 5c, 5d and 5g were moderately active against Staphylococcus aureus and Bacillus subtilis. Compound 7b was highly active against Bacillus subtilis and moderately active against Staphylococcus aureus. Other compounds were inactive against these strains of bacteria. The antifungal activities of these compounds were also tested against eight different fungal species. None of them were active against the fungi species tested.     

The synergistic activity of antibiotics combined with eight traditional Chinese medicines against two different strains of Staphylococcus aureus

The ethanolic extracts of eight traditional Chinese medicines and four antibiotics were investigated for their combined effects on the resistance of Staphylococcus aureus (S. aureus) in vitro. Methicillin resistant S. aureus, which was isolated from patient and a standard strain, were used. Our results showed that there are differences in the effects of many combinations used on the standard strain and resistant strain of S. aureus. The ethanolic extracts of Isatis tinctoria, Scutellaria baicalensis and Rheum palmatum can improve the antimicrobial activity of four antibiotics we used.     

Cytochemical differences in bacterial glycocalyx.

To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.     

Determination of antimicrobial activity and resistance to oxidation of moringa peregrina seed oil

The antimicrobial activity of the oil extracted with n-hexane from the seeds of Moringa peregrina was tested against Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans, C. tropicalis and C. glabrata. The oil proved effective against all of the tested microorganisms. Standard antibiotics (netilmycin, 5-flucytocine, intraconazole and 7-amino-4-methylcoumarin-3-acetic acid) were used for comparison. The resistance to oxidation of the extracted seed oil was also determined.     

Solvent-free microwave extraction and hydrodistillation of essential oils from endemic Origanum husnucanbaseri H. Duman, Aytac & A. Duran: comparison of antibacterial activity and contents

The essential oils (EOs) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from endemic Origanum husnucanbaseri H. Duman, Aytac & A. Duran were investigated using the gas chromatography-mass spectrometry system. The main constituents of both oils obtained from SFME and HD from O. husnucanbaseri are borneol (15.2-12.8%), α-terpineol (12.3-10.8%) and trans-sabinene hydrate (11.8-9.92%). The EO obtained from SFME contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than that from HD. The antibacterial activities of the EOs from SFME and HD were evaluated by the disc diffusion method against six bacterial strains. The EO extracted by SFME was more effective than the EO extracted by HD against the tested bacteria, except for Klebsiella pneumoniae American type culture collection (ATCC) 13883. Streptococcus pyogenes ATCC 19615 and Staphylococcus aureus ATCC 25923 in particular were more sensitive against the EO extracted by SFME.     

Synthesis and Antimicrobial Evaluations of Some Novel Mono‐, Bis‐, and Tris‐Nitro‐1,2,4‐Triazines

Substituted‐1,2,4‐triazines were conveniently synthesized in one pot by the cyclization of arylnitroformaldehyde hydrazone derivatives 1 and 5 with different primary amines in ~37% formaldehyde solution. The synthesized compounds were arranged into novel mono‐, bis‐, and tris‐nitro‐1,2,4‐triazine derivatives 2 , 3 , 4 , 6 , and 7 . The antibacterial and antifungal activity of the synthesized compounds were screened against bacterial strains Escherichia coli (as Gram − ve) and Staphylococcus aureus (as Gram + ve), and fungal strains Aspergillus flavus and Candida albicans . All the synthesized compounds exhibit various patterns of inhibitory activity on the two pathogenic bacterial strains. However, the same compounds showed no activity against the tested fungal strains.     

Antibacterial activity of flavonoids and triterpenoids isolated from the stem bark and sap of Staudtia kamerunensis Warb. (Myristicaceae)

The chemical investigation of the ethyl acetate extract of the stem bark of Staudtia kamerunensis and sap led to the isolation of six compounds which included three isoflavonoids: biochanin A (1), formononetin (2) and 3-(1,3-benzodioxol-5-yl)-5,6,7-trimethoxy-4H-1-benzopyran-4-one (3), one flavonoid: (-) epicatechin (4) and two pentacyclic triterpenoids (oleanan-12-ene-2α,3β -diol (5) and 2α,3β-dihydroxylup-20-ene (6). They were characterized by HREIMS (High Resolution Electron Ionisation Mass Spectrometry), NMR spectroscopy (1D and 2D) and comparison with existing data in literature. The crude extract and isolates were tested against twelve bacterial strains namely; Bacillus subtilis, Staphylococcus epidermidis, Enterococcus faecalis, Mycobacterium smegmatis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, Proteus mirabilis and Klebsiella pneumonia. Streptomycin, nalidixic acid and ampicillin were used as standard antibacterial drugs. The results revealed significant antibacterial activity for both the ethyl acetate partition and for the tested compounds, with the lowest MIC value being 15.625 μg/mL. A synergistic activity of the isolated triterpenoids was evaluated with interesting results. On a general note, the antibacterial activity of compound 5 was doubled specifically against Gram-negative bacterial strains. This could be a therapeutic antimicrobial pathway in face of the rising bacterial resistance. To the best of our knowledge, it is the first time that flavonoids and triterpenoids are isolated from this genus and species. It is also the first report of antibacterial studies on this species.     

SDIX RapidChek Listeria F.A.S.T. environmental test system for the detection of Listeria species on environmental surfaces

The SDIX RapidChek Listeria F.A.S.T. test system was validated against the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) cultural reference method for the detection of Listeria species on stainless steel, plastic, rubber, and painted concrete. The SDIX method uses a proprietary RapidChek Listeria enrichment media for a one-step, 24-40 h enrichment at 30 degrees C, and detects Listeria on an immunochromatographic lateral flow device in 10 min. Different Listeria species were used to spike each of the environmental surfaces. Environmental surfaces were spiked at levels ranging from 50 to 400 CFU/surface (1 in.2 swabs for painted concrete, 4 in.(2) for sponge). A total of 120 spiked samples were tested by the SDIX method at 24 and 40 h and the cultural reference method. Total confirmed positives were 49, 54, and 48 for the SDIX 24 h method, the SDIX 40 h method, and the USDA-FSIS cultural reference method, respectively. Nonspiked samples from all environmental surfaces were reported as negative for Listeria spp. by all methods. The overall Chi square was 0.017 (P = 0.104) and 0.611 (P= 0.566) after a 24 and 40 h enrichment, respectively, indicating that the test method was equivalent in performance to the reference method at both enrichment times. The SDIX method was evaluated for the detection of 50 Listeria and 35 non-Listeria bacterial strains. All 50 Listeria strains were detected by the method (100% sensitivity). Five out of 35 non-Listeria species gave light test signals when grown in nonselective broth culture and tested undiluted. However, when grown in the RapidChek Listeria F.A.S.T. proprietary media, only one bacterial strain (Staphylococcus aureus) was detected, giving a very low test signal (97% specificity). The method was shown to be robust toward several alterations in testing and storage conditions.     

Sensitivity of Staphylococcus aureus strains to broadband visible light

The phototoxic effect of illumination with broadband visible light on the viability of two Staphylococcus aureus strains was examined in the present study. A difference in the light sensitivity of the two strains was found. Illumination of the tested strains with a fluence rate of 180 J cm⁻² caused a reduction of up to 99.8% in the colony count of one of the strains (the "sensitive" strain). Illumination of the other strain (the "resistant" strain) resulted in a 55.5% reduction in viability. Proliferation of both strains was observed at low fluence rates of light. The phototoxic effect was found to be dependent on oxy radical production. The light-sensitive strain produced higher amounts of hydroxyl and superoxide radicals than the "resistant" strain. Adaptation to oxidative stress was exhibited only by the "resistant" strain. The "sensitive" strain produced ten times more endogenous porphyrins and secreted almost nine times more porphyrins than the resistant strain. Furthermore, the "resistant" strain produced twice as many carotenoids that protect the strain from illumination than the "sensitive" strain. These results indicate that high intensities of visible light cause bacterial photoeradication, a reaction which may assist wound healing by killing the infecting bacteria. On the other hand, low intensities of white light were found to enhance bacterial proliferation and thus prolong wound infection.     

Synthesis and antibacterial activity of some heterocyclic chalcone analogues alone and in combination with antibiotics

A series of simple heterocyclic chalcone analogues have been synthesized by Claisen Schmidt condensation reactions between substituted benzaldehydes and heteroaryl methyl ketones and evaluated for their antibacterial activity. The structures of the synthesized chalcones were established by IR and 1H-NMR analysis. The biological data shows that compounds p?, f? and t? had strong activities against both susceptible and resistant Staphylococcus aureus strains, but not activity against a vancomycin and methicillin resistant Staphylococcus aureus isolated from a human sample. The structure and activity relationships confirmed that compounds f?, f? and t? are potential candidates for future drug discovery and development.     

Synthesis of cobalt(II) and nickel(II) complexes of Ceclor (cefaclor) and preliminary experiments on their antibacterial character

Cobalt(II) and nickel(II) complexes of the antibacterial drug Ceclor have been synthesized and characterized on the basis of their elemental analysis, molar conductance, magnetic moment and electronic and infrared spectral data. These complex have been, then subjected to screening for their antibacterial properties against bacterial species such as Streptococcus pyogenes, Streptococcus pneumoniae, Staphylococcus aureus and Escherichia coli. In comparison to uncomplexed Ceclor, the metal complexes have been shown to be more antibacterial.     

Synthesis and antimicrobial activity of quinoline-based 2-pyrazolines

A series of 2-pyrazolines was prepared in a reaction of quinolinylchalcones with phenyl hydrazine under both conventional and microwave-induced heating. Structures of the synthesized compounds were characterized by spectroscopic data and CHN analyses. All prepared compounds were tested for antimicrobial activity against bacterial strains, viz. Staphylococcus aureus, Salmonella typhii, Escherichia coli, and Shigella dysentery. Almost all synthesized compounds have shown antimicrobial activity; however, compounds with a chloro group as a substituent have been found to be more effective.