Antibiotic therapy of cystic fibrosis in children]

It is postulated that P. aeruginosa in monoculture or in association with Staphylococcus aureus keeps its leading position in chronic bacterial inflammatory broncho-pulmonary processes in children with cystic fibrosis. Antibiotic resistant strains of Burkholderia cepacia, Stenotrophomonas maltophila, Alcaligenes xylosoxidans were revealed (7.1% of the strains). P. aeruginosa strains were susceptible to aminoglycosides, ciprofloxacin, and polymixin B. Susceptibility of smooth and mucoid forms of P. aeruginosa to ceftazidime stayed at the level of 49.6-57.1%. Such microbial associations as P. aeruginosa sm. + S. aureus, P. aeruginosa sm. + P. aeruginosa muc. + S. aureus were mainly susceptible to ciprofloxacin, aminoglycosides and resistant to ceftasidime. Meropenem, cefepim and ciprofloxacin are highly effective antibiotics for the treatment of broncho-pulmonary processes exacerbations at children with chronic P. aeruginosa cystic fibrosis. Intravenous use of antibiotics out of hospital for the treatment of the children with cystic fibrosis is clinically effective, and is economically and psychologically reasonable. It should be used more widely in medical practice.     

Efficacy and safety of cefepime in the treatment of bronchopulmonary disease exacerbation in pediatric patients with mucoviscidosis]

Clinicobacteriological effect of cefepime (in combination with amikacin) was studies in 25 pediatric patients of the age of 7 to 17 years with a mixed form of mucoviscidosis at the stage of the bronchopulmonary infection exacerbation. The basic pathogens isolated from the sputum were: Pseudomonas aeruginosa sm., P. aeruginosa muc. (67.5%) and Staphylococcus aureus (29.1%). The 2-week treatment course resulted in a marked clinical effect with improvement of the lung functional indices and eradication of the majority of the S. aureus strains (81.2%) and half of the P. aeruginosa strains (49.6%). The only side effect was moderate diarrhea not requiring discontinuation of the drug use.     

RISA-HPLC analysis of lung bacterial colonizers of cystic fibrosis children

Microbiological analysis of sputum samples, from children affected by cystic fibrosis (CF) and showing signs of acute or chronic infections, is routinely performed by culture-dependent approaches involving selective media and biochemical tests. These identification schemes are time-consuming, and may lead to false negative results. The aim of this work was to evaluate the efficacy of a Ribosomal Intergenic Spacer Analysis (RISA) coupled to high performance liquid chromatography (HPLC) for the detection and monitoring of CF lung microbial colonizers including Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, the Burkholderia cepacia complex, Stenotrophomonas maltophilia, and Achromobacter xylosoxidans. These RISA-HPLC analyses were performed over a 10-months period on infants (below 18 months) and children that were or were not yet known to be colonised by P. aeruginosa. The RISA-HPLC profiles were found specific of the patients' microbial communities. A specific P. aeruginosa RISA-HPLC peak corresponding to 550 bp PCR products was recorded, and used to investigate P. aeruginosa persistence through time and after various therapeutic treatments. The RISA-HPLC profiles showed the CF children to be colonized by few bacterial species, and sometimes revealed peaks corresponding to bacterial species that were not detected by the selective plating approaches. Significant RISA-HPLC infra-specific variations were observed for most bacterial colonizers of CF lungs except P. aeruginosa. These species could yield as much as 5 distinct RISA-HPLC peaks, with some of these profiles being strain-specific. RISA-HPLC shows a great potential for revealing colonization by novel emerging pathogens, and for evaluating the efficacy of therapeutic treatments on the global bacterial community of CF lungs.     

In Vitro Bactericidal Evaluation of a Low Phase Transition Temperature Liposomal Tobramycin Formulation as a Dry Powder Preparation Against Gram Negative and Gram Positive Bacteria

Abstract

In previous studies, delivery of a liquid preparation of encapsulated tobramycin in fluid liposomes, called Fluidosomes, has showed a marked improvement in the bactericidal activity against in-vitro and in-vivo extracellular infections. To examine the possibility of developing aerosol treatment using dehydrated Fluidosomes for the treatment of chronic pulmonary infections, freeze-dried preparations of tobramycin and Fluidosomes were tested against cultures of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Burk-holderia cepacia, Escherichia coli and Staphylococcus aureus. Bacterial colonies were enumerated 0, 1, 3, 6 and 16 h after the addition of the antibiotic. Sixteen hours post-treatment, the growth of P. aeruginosa, S. maltophilia, B. cepacia and E. coli in the presence of sub-minimal inhibitory concentrations of tobramycin was significantly lowered respectively by 17 (P < 0.01), 40 (P < 0.001), 47 (P < 0.001), and 50 (P < 0.001) times in comparison with growth in the presence of free antibiotic. No improvement was observed against 5. aureus. Results obtained in this study suggest that: 1) the dehydrated form of liposomal antibiotic maintains the ability to increase penetration of the antibiotic in gram negative bacterial cells; 2) the development of aerosolization methods to administer dehydrated liposomes associated with high concentrations of antibiotic could be a practical and efficient way of treating chronic pulmonary infections caused by resistant bacteria.     

In vitro antibacterial activity of a 7-O-beta-D-glucopyranosyl-nutanocoumarin from Chaptalia nutans (Asteraceae)

Ethanolic crude extracts from the roots of Chaptalia nutans, traditionally used in Brazilian folk medicine, were screened against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa by using the disk diffusion test technique. S. aureus with 14 mm inhibition zone was considered susceptible. E. coli and P. aeruginosa without such a zone were considered resistant. As a result of this finding, the ethanolic crude extract was fractionated on silica gel column chromatography into five fractions. The ethyl acetate fraction was active against S. aureus and Bacillus subtilis. Further column chromatography separation of the ethyl acetate fraction afforded 30 fractions, which were assayed against S. aureus. Fractions 16 and 17 showed inhibition zones with S. aureus, indicating the presence of active compounds, and were subjected to purification by repeated preparative thin layer chromatography. The pure compound 7-O-beta-D-glucopyranosyl-nutanocoumarin inhibited B. subtilis and S. aureus at concentrations of 62.5 g/ml and 125 g/ml, respectively. The antibacterial property of C. nutans appears to have justified its use for the treatment of wounds, which are contaminated through bacterial infections.     

嗜麦芽窄食单胞菌感染危险因素与其耐药特征的研究

目的　研究嗜麦芽窄食单胞菌感染危险因素及其耐药特征,以提高临床对嗜麦芽窄食单胞菌防治水平。方法　对6 8例嗜麦芽窄食单胞菌感染者的临床资料进行统计分析,并用K- B法测其耐药情况。结果　嗜麦芽窄食单胞菌占非发酵革兰阴性杆菌的9.5 2 % ,居铜绿假单胞菌与不动杆菌之后,列第3位。药敏试验表明,该菌广泛耐药,敏感率>5 0 %者仅有复方新诺明、替卡西林-克拉维酸与头孢哌酮-舒巴坦,在感染者中,有85 .3%患者有基础病,98.5 %使用过广谱抗生素,70 .6 %曾接受侵入性检查和治疗。结论　嗜麦芽窄食单胞菌已成为医院感染重要致病菌,多发生在免疫功能低下的老人,慢性疾病、长期疾病、长期接受激素及使用抗菌药物、施行各种侵入性检查和治疗的患者。嗜麦芽窄食单胞菌对多种抗生素耐药,一旦感染,治疗颇为困难     

Synthetic peptide vaccine and antibody therapeutic development: prevention and treatment of Pseudomonas aeruginosa

Pseudomonas aeruginosa and Pseudomonas maltophilia account for 80% of opportunistic infections by pseudomonads. Pseudomonas aeruginosa is an opportunistic pathogen that causes urinary tract infections, respiratory system infections, dermatitis, soft tissue infections, bacteremia, and a variety of systemic infections, particularly in patients with severe burns, and in cancer and AIDS patients who are immunosuppressed. Pseudomonas aeruginosa is notable for its resistance to antibiotics, and is therefore a particularly dangerous pathogen. Only a few antibiotics are effective against Pseudomonas, including fluoroquinolones, gentamicin, and imipenem, and even these antibiotics are not effective against all strains. The difficulty treating Pseudomonas infections with antibiotics is most dramatically illustrated in cystic fibrosis patients, virtually all of whom eventually become infected with a strain that is so resistant that it cannot be treated. Since antibiotic therapy has proved so ineffective as a treatment, we embarked on a research program to investigate the development of a synthetic peptide consensus sequence vaccine for this pathogen. In this review article we will describe our work over the last 15 years to develop a synthetic peptide consensus sequence anti-adhesin vaccine and a related therapeutic monoclonal antibody (cross-reactive to multiple strains) to be used in the prevention and treatment of P. aeruginosa infections. Further, we describe the identification and isolation of a small peptide structural element found in P. aeruginosa strain K (PAK) bacterial pili, which has been proven to function as a host epithelial cell-surface receptor binding domain. Heterologous peptides are found in the pili of all strains of P. aeruginosa that have been sequenced to date. Several of these peptide sequences have been used in the development of an consensus sequence anti-adhesin vaccine targeted at the prevention of host cell attachment and further for the generation of a monoclonal antibody capable of prevention and treatment of existing infections.     

Antibacterial activity of ethanolic and aqueous extracts of Acacia aroma Gill. ex Hook et Arn

The purpose of the present study was to investigate the antibacterial activity of seven ethanolic extracts and three aqueous extracts from various parts (leaves, stems and flowers) of A. aroma against 163 strains of antibiotic multi-resistant bacteria. The disc diffusion assay was performed to evaluate antibacterial activity of the A. aroma crude extracts, against several Gram-positive bacteria (E. faecalis, S. aureus, coagulase-negative stahylococci, S. pyogenes, S. agalactiae, S. aureus ATCC 29213, E. faecalis ATCC 29212) and Gram-negative bacteria (E. coli., K. pneumoniae, P. mirabilis, E. cloacae, S. marcescens, M morganii, A. baumannii, P. aeruginosa, S. maltophilia, E. coli ATCC 35218, P. aeruginosa ATCC 27853, E. coli ATCC 25922). All ethanolic extracts showed activity against gram-positive bacteria. Among all obtained extracts, only leaf and flower fluid extracts showed activity against Gram-negative bacteria. Based on this bioassay, leaf fluid extracts tended to be the most potent, followed by flower fluid extracts. Minimal inhibitory concentration (MIC) values of extracts and antibiotics were comparatively determined by agar and broth dilution methods. Both extracts were active against S. aureus, coagulase-negative stahylococci, E. faecalis and E. faecium and all tested Gram-negative bacteria with MIC values from 0.067 to 0.308 mg/ml. In this study the minimal bactericidal concentration (MBC) values were identical or twice as high than the corresponding MIC for leaf extracts and four or eight times higher than MIC values for flower extracts. This may indicate a bactericidal effect. Stored extracts have similar antibacterial activity as recently obtained extracts. The A. aroma extracts of leaves and flowers may be useful as antibacterial agents against Gram- negative and Gram-positive antibiotic multi-resistant microorganisms.     

Stenotrophomonas maltophilia interaction with human epithelial respiratory cells in vitro

Bacteria of Stenotrophomonas maltophilia have been isolated with increasing frequency from the airways of cystic fibrosis (CF) patients, usually following P. aeruginosa infections, but their adherence to human epithelial respiratory cells has never been investigated. In this study, various S. maltophilia strains were seen to adhere to epithelial respiratory cells in vitro, mainly along intercellular junctions. Bacteria could also enter into host cells, as determined by the gentamicin exclusion assay and transmission electron microscopy. Cells co-incubated with P. aeruginosa and S. maltophilia exhibited a significantly decreased adherence of these latter bacteria. No decrease in S. maltophilia adherence was observed when co-infection was carried out with heat-killed P. aeruginosa or when respiratory cells were first incubated with P. aeruginosa, before incubation with S. maltophilia. Our data suggest that P. aeruginosa infections do not account for the increased prevalence of S. maltophilia in CF patient airways, that thermolabile products from P. aeruginosa can control the adherence of S. maltophilia to respiratory cells and also that these two bacteria do not compete for cell receptors.     

Efficacy and safety of cefoperazone/sulbactam in the treatment of children with mucoviscidosis during exacerbation of the bronchopulmonary process]

The use of cefoperazone/sulbactam in combination with amikacin in the treatment of 20 patients with mucoviscidosis and exacerbation of bronchopulmonary pathological process resulted in marked positive dynamics of the clinical and functional indices of the lungs state. The bacteriological effect with respect to the main pathogens in the cases of mucoviscidosis was strain-dependent: eradication of 10 (83.4%) out of 12 Staphylococcus aureus strains and only 3 (15.8%) out of 19 Pseudomonas aeruginosa strains. The most frequent adverse reaction was diarrhea (5 children) successfully corrigated by loperamide. Discontinuation of the drug use was required in 3 patients because of macrohematuria (1 child) and allergic eruption.     

The experimental and clinical use of polymyxin,chloromycetin, and aureomycin

Polymyxin is an effective antibiotic for the treatment of severe infections produced by Ps. aeruginosa, H. pertussis, H. influenzae, E. coli, and A. aerogenes. Its toxicity to date precludes its general use in infections susceptible to its therapeutic effects. Chloromycetin has been demonstrated to be an effective antibiotic agent for the treatment of rickettsial diseases and typhoid fever. It will undoubtedly prove effective in the treatment of other infections produced by certain Gram-negative micro-organisms and viral agents. Aureomycin has been shown to be an active antibiotic agent against rickettsial diseases, primary atypical pneumonia, acute brucellosis, pneumococcal, streptococcal, and staphylococcal infections, urinary tract infections produced by E. coli, A. aerogenes and Strept. fecalis, certain types of infections of the eye, and in subacute bacterial endocarditis when the infecting agent is Strept. fecalis. Its clinical use in forms of extrapulmonary tuberculosis is in a completely experimental stage. It is not recommended in typhoid fever or in infections due to Ps. aeruginosa or P. vulgaris, and it seems to be ineffective in whooping cough. To date, neither chloromycetin nor aureomycin has shown significant signs of systemic toxicity.     

THE EXPERIMENTAL AND CLINICAL USE OF POLYMYXIN,CHLOROMYCETIN, AND AUREOMYCIN

Polymyxin is an effective antibiotic for the treatment of severe infections produced by Ps. aeruginosa, H. pertussis, H. influenzae, E. coli, and A. aerogenes. Its toxicity to date precludes its general use in infections susceptible to its therapeutic effects.Chloromycetin has been demonstrated to be an effective antibiotic agent for the treatment of rickettsial diseases and typhoid fever. It will undoubtedly prove effective in the treatment of other infections produced by certain Gram-negative micro-organisms and viral agents.Aureomycin has been shown to be an active antibiotic agent against rickettsial diseases, primary atypical pneumonia, acute brucellosis, pneumococcal, streptococcal, and staphylococcal infections, urinary tract infections produced by E. coli, A. aerogenes and Strept. fecalis, certain types of infections of the eye, and in subacute bacterial endocarditis when the infecting agent is Strept. fecalis. Its clinical use in forms of extrapulmonary tuberculosis is in a completely experimental stage. It is not recommended in typhoid fever or in infections due to Ps. aeruginosa or P. vulgaris, and it seems to be ineffective in whooping cough.To date, neither chloromycetin nor aureomycin has shown significant signs of systemic toxicity.     

Pattern differentiation in co-culture biofilms formed by Staphylococcus aureus and Pseudomonas aeruginosa

Biofilm infections may not simply be the result of colonization by one bacterium, but rather the consequence of pathogenic contributions from several bacteria. Interspecies interactions of different organisms in mixed-species biofilms remain largely unexplained, but knowledge of these is very important for understanding of biofilm physiology and the treatment of biofilm-related infectious diseases. Here, we have investigated interactions of two of the major bacterial species of cystic fibrosis lung microbial communities -Pseudomonas aeruginosa and Staphylococcus aureus- when grown in co-culture biofilms. By growing co-culture biofilms of S. aureus with P. aeruginosa mutants in a flow-chamber system and observing them using confocal laser scanning microscopy, we show that wild-type P. aeruginosa PAO1 facilitates S. aureus microcolony formation. In contrast, P. aeruginosa mucA and rpoN mutants do not facilitate S. aureus microcolony formation and tend to outcompete S. aureus in co-culture biofilms. Further investigations reveal that extracellular DNA (eDNA) plays an important role in S. aureus microcolony formation and that P. aeruginosa type IV pili are required for this process, probably through their ability to bind to eDNA. Furthermore, P. aeruginosa is able to protect S. aureus against Dictyostelium discoideum phagocytosis in co-culture biofilms.     

Anti-infective properties of Lactobacillus fermentum against Staphylococcus aureus and Pseudomonas aeruginosa

Surgical wounds and implant-associated Staphylococcus aureus and Pseudomonas aeruginosa infections are often difficult to treat because of limited susceptibility of several of these strains to conventional antibiotics. As a result, there is a constant need for new alternative drugs. The aim of this study was to investigate the antimicrobial properties of Lactobacillus fermentum, a probiotic bacterium, which we have isolated from colonic biopsies. The inhibition of S. aureus and P. aeruginosa growth was evaluated by coincubating with L. fermentum strains. Growth inhibition was tested for several of their clinical isolates using agar well diffusion assays. For biofilm assay S. aureus and P. aeruginosa were grown on the glass slides and in 96-well plates in presence of 2.5 μg/ml culture filtrate of L. fermentum. Biofilms were photographed using confocal microscope or stained with 0.1% crystal violet. Reduction in the cytotoxicity of S. aureus and P. aeruginosa was observed in presence of 2.5 μg/ml L. fermentum-spent media. Using in vitroexperiments, we showed that L. fermentum-secreted compound(s) inhibits the growth, cytotoxicity and biofilm formation of several S. aureus and P. aeruginosa strains. Compound(s) present in the culture supernatant of L. fermentum may have promising applications in treating hospital-acquired infections.     

椒样薄荷、薄荷和苏格兰留兰香精油与抗生素的协同抑菌功能

以开花期的椒样薄荷（Mentha×piperita）、薄荷（M.haplocalyx）和苏格兰留兰香（M.×gentilis）叶片部位提取的精油为研究对象,通过GC-MS分析,并采用纸片扩散法研究了3种精油单独使用及与抗生素联合使用时对金黄色葡萄球菌、蜡状芽孢杆菌、大肠杆菌、绿脓杆菌和肺炎克雷伯氏菌的抑制情况。结果表明,（1）椒样薄荷与薄荷精油中含量最高的成分为薄荷醇、薄荷酮和异薄荷酮,苏格兰留兰香精油的主要成分为香芹酮和柠檬烯。薄荷和苏格兰留兰香精油符合欧洲药典与ISO标准,椒样薄荷需要继续改良以提高其精油品质与抑菌功能。（2）精油单独使用时,Pseudomonas aeruginosa ATCC15442对椒样薄荷精油和薄荷精油敏感;P.aeruginosa ATCC27853对薄荷精油和苏格兰留兰香精油敏感。精油与抗生素联合使用时抑菌范围和强度均有所改变：绿脓杆菌的2个菌株对精油与抗生素的组合最为敏感,其中,椒样薄荷精油与头孢他啶的组合对P.aeruginosa ATCC15442显示出最强的增效作用,薄荷精油与头孢他啶混合之后对P.aeruginosa ATCC27853出现拮抗作用。Staphylococcus aureus ATCC25923对所有精油以及精油与抗生素混合物均有抗性。（3）椒样薄荷、薄荷和苏格兰留兰香精油的不同成分及其含量差异不仅对精油品质有影响,而且影响精油对测试菌种的抑制作用,可考虑将其作为薄荷属植物品质育种的参考指标。     

Comparative activity of tobramycin and gentamicin against Pseudomonas,Proteus and Providencia species.

Tobramycin is a new antibiotic resembling gentamicin. We measured the minimal inhibitory concentrations of these two antibiotics against five bacterial species that cause hospital-acquired infections and are resistant to many presently available antibiotics. The organisms tested were 500 strains of Pseudomones aeruginosa, 100 strains of each of Proteus rettgeri and Pr. morganii, 50 strains of Pr. vulgaris and 250 strains of Providencia stuartii. Tobramycin was 2 to 4 times more active than gentamicin against Ps. aeruginosa; all except 6 of 70 strains resistant to 4 mug/ml of gentamicin were sensitive to 4 mug/ml of tobramycin. The two antibiotics showed a similar degree of activity against the other four species. Tobramycin promises to be of particular value in the treatment of Pseudomonas infections.     

Modulation of antibiotic resistance in bacterial pathogens by oleanolic acid and ursolic acid

Antibiotic resistance among bacterial pathogens is a serious problem for human and veterinary medicine, which necessitates the development of novel therapeutics and antimicrobial strategies. Some plant-derived compounds, e.g. pentacyclic triterpenoids such as oleanolic acid (OA) and ursolic acid (UA), have potential as a new class of antibacterial agents as they are active against many bacterial species, both Gram-positive and Gram-negative, and specifically target the cell envelope. The aim of the present study was to investigate the influence of OA and UA on the susceptibility of four bacterial pathogens (Pseudomonas aeruginosa, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus epidermidis) to the β-lactam antibiotics ampicillin (Ap) and oxacillin (Ox). Antimicrobial assays were conducted with bacteria growing in liquid suspension cultures (planktonic cells) or as biofilms. Using FICI value estimation and the time-kill method it was demonstrated that in some combinations, the tested compounds acted in synergy to lower the susceptibility of S. aureus, S. epidermidis and L. monocytogenes to ampicillin and oxacillin, but no synergy was observed for P. aeruginosa. These results indicate that OA and UA may be useful when administered in combination with β-lactam antibiotics to combat bacterial infections caused by some Gram-positive pathogens.     

椒样薄荷、薄荷和苏格兰留兰香精油与抗生素的协同抑菌功能

以开花期的椒样薄荷(Mentha × piperita)、薄荷(M. haplocalyx)和苏格兰留兰香(M. × gentilis)叶片部位提取的精油为研究对象, 通过GC-MS分析, 并采用纸片扩散法研究了3种精油单独使用及与抗生素联合使用时对金黄色葡萄球菌、蜡状芽孢杆菌、大肠杆菌、绿脓杆菌和肺炎克雷伯氏菌的抑制情况。结果表明, (1) 椒样薄荷与薄荷精油中含量最高的成分为薄荷醇、薄荷酮和异薄荷酮, 苏格兰留兰香精油的主要成分为香芹酮和柠檬烯。薄荷和苏格兰留兰香精油符合欧洲药典与ISO标准, 椒样薄荷需要继续改良以提高其精油品质与抑菌功能。(2) 精油单独使用时, Pseudomonas aeruginosa ATCC 15442对椒样薄荷精油和薄荷精油敏感; P. aeruginosa ATCC 27853对薄荷精油和苏格兰留兰香精油敏感。精油与抗生素联合使用时抑菌范围和强度均有所改变: 绿脓杆菌的2个菌株对精油与抗生素的组合最为敏感, 其中, 椒样薄荷精油与头孢他啶的组合对P. aeruginosa ATCC 15442显示出最强的增效作用, 薄荷精油与头孢他啶混合之后对P. aeruginosa ATCC 27853出现拮抗作用。Staphylococcus aureus ATCC 25923对所有精油以及精油与抗生素混合物均有抗性。(3) 椒样薄荷、薄荷和苏格兰留兰香精油的不同成分及其含量差异不仅对精油品质有影响, 而且影响精油对测试菌种的抑制作用, 可考虑将其作为薄荷属植物品质育种的参考指标。     

Increase of resistance to Pseudomonas aeruginosa infection in mice caused by Staphylococcus aureus]

In our study of opportunistic pathogens, we have some indication that Staphylococcus aureus can increase resistance in mice against Pseudomonas aeruginosa. Intraperitoneal injections of sublethal doses of S. aureus had a protective effect in mice against lethal doses of P. aeruginosa, more so if living and coagulase-positive S. aureus strains were injected. This protective effect was obtained both with laboratory and freshly isolated hospital strains. The interval between these infections can be extended from 2 h up to 1 week and it is still possible to observe the resistance phenomenon. The increased resistance was accompanied by a decrease in viable units of P. aeruginosa in the peritoneal cavity of mice 6 h after the injection of this species. There was no protection by S. aureus against Candida albicans in similar experimental conditions. These observations indicate that intermicrobial ecology, understood here as the previous presence of another species in a host, may be a significant factor in the resistance to infection with opportunistic pathogens such as P. aeruginosa.