The estimation of usefulness of Pseudomonas bacteriophages in epidemiological investigations of Pseudomonas aeruginosa clinical strains

Out of 20 Pseudomonas phages, 17 were most suitable for typing of Pseudomonas aeruginosa strains isolated from different sources of human infections. These phages have been classified into three taxons based on coefficient of correlation of their lytic activity. Out of these strains only one appeared nontypeable. 240 distinquished phagotypes were classified into three groups and seven subgroups. This schema of classification was used in the epidemiological investigations of the Pseudomonas strains in relation to the category of infection and the place of isolation. Some statisticaly significant differences were detected. Various possibilities of applications of typing set of Pseudomonas phages are discussed.     

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.     

Drug susceptibility of Pseudomonas aeruginosa strains isolated from patients of a hospital and specialistic outpatients clinics of the SP ZOZ in Nidzica

The aim of this study was to evaluate a frequency of isolation and antimicrobial susceptibility testing (AST) of Pseudomonas aeruginosa strains cultured from clinical specimens collected from patients hospitalized in wards and specialistic outpatients clinics of a hospital in Nidzica (01. 09. 2000 -31. 12. 2003). During over three years 392 Pseudomonas aeruginosa strains were cultured from 16346 clinical samples provided to bacteriological laboratory. P. aeruginosa strains were isolated from 2.5% of examined specimens. Susceptibility of Pseudomonas aeruginosa strains to antimicrobial agents was tested. The highest in vitro activity against clinical P. aeruginosa strains demonstrated imipenem. One strain was resistant to imipenem. This strain was isolated from a patient of a surgical department. Metalo-beta-lactamase was not detected (MBL-negative strain).Twenty nine strains were ESBL producer (7.4% of all strains). The contribution of Pseudomonas aeruginosa strains to the etiology of nosoconial and ambulatory infections increases. In vitro activity of antibacterial agents against P. aeruginosa strains should be monitored during therapy of infections. Resistance to antibiotics/chemothe-rapeutics may be acquired during treatment with antibacterial agent to which P. aeruginosa strain was susceptible according to the antibiogram.     

Epidemiology of Pseudomonas aeruginosa in a Burns Hospital: Evaluation of Serological, Bacteriophage, and Pyocin Typing Methods

In a retrospective study 36 cultures of Pseudomonas aeruginosa, isolated from patients with fatal Pseudomonas burn wound sepsis and from burned patients with nonfatal P. aeruginosa infections, were used to evaluate the consistency and reliability of serological, phage, and pyocin typing as epidemiological tools. Frequency distributions of positive reactions were analyzed by a computer in a 3-way chi-square test, and a high degree of consistency was demonstrated for each method. From these data, 75% of the cultures were differentiated by serological, 90% by phage, and 100% by pyocin typing. There was no significant difference among organisms isolated from fatal cases of burn wound sepsis and organisms from patients with nonfatal infections (chi(2) = 0.3418; P = 0.9870). The combined typing system was a sensitive and reliable epidemiological tool for intraspecific differentiation of P. aeruginosa.     

Production of cytotoxin by clinical strains of Pseudomonas aeruginosa

Presence of cytotoxin was studied in extracts of 57 strains of Pseudomonas aeruginosa (46 bacteremia, 4 environmental, and 7 Fisher immunotype), 10 Pseudomonas species, and 7 nonpseudomonas isolates. Cytotoxin was identified by Western immunoblot in extracts of all P. aeruginosa isolates. None of the Pseudomonas species or nonpseudomonas isolates were shown to produce this protein. No immunologic cross-reactivity was observed between cytotoxin antibody and P. aeruginosa alkaline protease, toxin A, or elastase. In partially purified extracts of two bacteremia strains and PA 158 (parent strain for cytotoxin production), detection of cytotoxin by Western immunoblot was correlated with biological activity, as measured by the cell swelling assay. Cytotoxin appears to be produced by all strains of P. aeruginosa and biological activity can be demonstrated in extracts of the strains tested. This biological activity is neutralized by specific antibody. Because of its known marked cytotoxic effect on most eukaryotic cells, P. aeruginosa cytotoxin might be an important factor in the pathogenesis of P. aeruginosa infections.     

Results of using polyvalent Pseudomonas aeruginosa vaccine in children with burns by various medical centers

Polyvalent Pseudomonas aeruginosa vaccine, prepared at the Institute of Hematology from 10 hospital strains isolated from burn wounds, was administered to 32 children with extensive and deep burns. The vaccine was well tolerated. The vaccine produced a high degree of the immunity against Pseudomonas aeruginosa infection. Agglutinin serum titre increased significantly. Vaccination either prevented or inhibited the infection of burn wounds with Pseudomonas aeruginosa in all immunized children. The symptoms of Pseudomonas aeruginosa infection usually disappeared following one or two vaccinations. Bacteriemia caused by P. aeruginosa was not observed in 31 out of 32 children. In the remaining child transient bacteriemia was noted. No septicemia caused by P. aeruginosa was seen. Due to the high efficiency of the polyvalent P. aeruginosa vaccine all burned children with burns exceeding 10% of the total body surface should by vaccinated to prevent the life-threatening infections with Pseudomonas aeruginosa.     

铜绿假单胞菌的院内感染分布及耐药性的调查

目的了解铜绿假单胞菌（PA）在医院内感染的分布特点及其耐药性,指导临床合理用药,降低医院感染率。方法回顾分析2005年1月至2008年11月我院临床分离的铜绿假单胞菌152株,按WHO推荐的NC-CLS标准方法（K—B法）进行药敏试验,分析菌株的临床分布特征及体外药敏结果。结果铜绿假单胞菌在临床上主要以呼吸道感染为主。在17种临床常用抗生素中,多表现为多重耐药。美洛培南、亚胺培南及左旋氧氟沙星抗PA效果最好,耐药率分别只有14．47％、14．47和5．26％。结论多重耐药铜绿假单胞菌在临床广泛存在,应当根据临床体外药敏结果合理选择抗菌药物进行治疗,以取得良好临床效果并减少耐药菌产生;同时规范院内感染控制措施,减少耐药菌株的播散。     

126株铜绿假单胞菌的临床分布及耐药性分析

目的调查分析象山县中医医院铜绿假单胞菌的临床分布及药敏情况,为临床合理选用抗生素提供可靠的依据。方法采集疑似患者的标本,进行分离、培养与鉴定。采用自动微生物鉴定／药敏分析仪进行鉴定及药敏试验,对2012年7月至2013年10月分离出的126株铜绿假单胞菌（包括21株黏液型铜绿假单胞菌）的分布及耐药性进行回顾性分析。结果126株铜绿假单胞菌临床主要分布情况：痰占80．2％,尿液占11．1％,脓液占7．1％,以呼吸道感染为主。对铜绿假单胞菌保持活性较强同时耐药率〈20％的抗生素有阿米卡星、妥布霉素、亚胺培南、哌拉西林／他唑巴坦,其中碳青霉烯类耐药率升至5％,原来被认为抗铜绿假单胞菌较为有效的喹诺酮类抗生素的耐药率也有了很大提升,左氧氟沙星耐药率升至33％。黏液型铜绿假单胞菌的体外抗菌药物敏感试验耐药性较弱,且明显弱于非黏液型铜绿假单胞菌的耐药性。结论铜绿假单胞菌为医院呼吸道感染的常见致病菌,对多种抗菌药物呈不同程度耐药。加强动态监测,合理使用抗菌药物,对铜绿假单胞菌感染的预防和药物治疗具有重要指导意义。     

Human anti-Pseudomonas aeruginosa outer membrane proteins IgG cross-protective against infection with heterologous immunotype strains of P. aeruginosa.

In order to develop an effective means to treat and prevent Pseudomonas aeruginosa infections, we have purified P. aeruginosa outer membrane protein (Oprs)-specific human IgG antibody using a large-scale affinity column. In this study, we investigated the cross-protective activity of the purified anti-Oprs IgG against various immunotype strains of P. aeruginosa. The anti-Oprs IgG reacted with Oprs isolated from seven Fisher-Devlin immunotype strains of P. aeruginosa and was able to promote opsonophagocytic killing of all seven immunotype strains by human phagocytic cells. Administration of 500 microg anti-Oprs IgG to mice raised the LD50 of the P. aeruginosa strains by 8-250-fold, indicating the protective capacity against heterologous P. aeruginosa strains as well as homologous strains. In contrast, despite high titers against P. (aeruginosa Oprs, total serum IgG isolated from burn patient sera was no better than normal serum IgG in protecting mice from infection with P. aeruginosa. These data demonstrate that the affinity-purified human anti-Oprs IgG could afford protection against heterologous immunotype P. aeruginosa strains and provide a rationale to use anti-Oprs IgG as an adjunct for treatment of P. aeruginosa infections in humans.     

Quantitative real-time PCR study of the influence of probiotic culture soluble fraction on the expression of Pseudomonas aeruginosa quorum sensing genes

The opportunistic pathogen Pseudomonas (Ps.) aeruginosa causes severe infections, particularly in immunocompromised individuals and patients with cystic fibrosis (CF). A serious side effect of antibiotic therapy in Ps. aeruginosa infections is the development of resistance to antibiotics. During the infection process Ps. aeruginosa forms biofilms, rendering bacterial cells more resistant to disinfectants, antibiotics and the action of host immune defense effectors. Pseudomonas aeruginosa employs the intercellular communication system, known as quorum sensing (QS) to coordinate the expression of tissue-damaging factors. Since the QS systems controls the production of different virulence factors, it is possible that the inhibition of its regulatory activity to severely compromise the ability of Ps. aeruginosa to cause infections in humans. Many studies have shown that some probiotic strains exhibit inhibitory activity on different virulence properties of pathogenic bacteria (adherence to cellular or inert substrate, soluble virulence factors expression). The aim of the present study was to investigate by real-time RT-qPCR the influence of probiotic culture soluble factors on the QS genes expression in 30 Ps. aeruginosa strains isolated from patients hospitalized in the National Institute for Cardiovascular Infections, Prof. C.C. Iliescu Fundeni Hospital, Bucharest. The results of the real time RT-qPCR have shown that in all Ps. aeruginosa strains grown in the presence of probiotic culture sterile filtrates, the level of QS genes expression was reduced comparatively with those from control cultures. In conclusion, these results proved that the inhibition of virulence factors regulation mechanisms by soluble molecules secreted by probiotics could represent an interesting way pathogenicity and virulence attenuation in Ps. aeruginosa nosocomial strains.     

The occurrence of denitrification in extremely halophilic bacteria

Abstract A total of 97 aerobic and facultatively anaerobic bacteria, and 3 Candida albicans , were tested for their ability to inhibit the growth of Haemophilus influenzae . Only strains of Pseudomonas aeruginosa showed any inhibitory effect and all 5 strains tested clearly inhibited the growth of all 10 strains of H. influenzae . The inhibition of H. influenzae . by Ps. aeruginosa may play a role in the establishment of chronic Ps. aeruginosa infections in the respiratory tracts of patients with bronchiectasis and cystic fibrosis (CF).     

Effect of anionic detergents on wild-type and envelope mutants of Escherichia coli and Pseudomonas aeruginosa

Escherichia coli UB1005 (DCO), an envelope mutant (DC2), Pseudomonas aeruginosa 799 and an envelope mutant (799/61) were exposed to sodium deoxycholate (DOC), sarkosyl and sodium lauryl sulphate (SLS). DOC was the least effective lytic agent, but the two Ps. aeruginosa strains, especially 799/61, were more susceptible to DOC and sarkosyl than the E. coli ones. SLS was an efficient lysing agent, although Ps. aeruginosa 799 was the least susceptible of the four strains. DC2 was lysed more rapidly and to a greater extent than UB1005 by all three agents. The mutant strains, especially DC2, were more sensitive to selective media than the wild-type ones.     

Anaerobic transfer of antibiotic resistance from Pseudomonas aeruginosa

Pseudomonas aeruginosa, an opportunistic pathogen that often initiates infections from a reservoir in the intestinal tract, may donate or acquire antibiotic resistance in an anaerobic environment. Only by including nitrate and nitrite in media could antibiotic-resistant and -sensitive strains of P. aeruginosa be cultured in a glove box isolator. These anaerobically grown cells remained sensitive to lytic phage isolated from sewage. After incubation with a phage lysate derived from P. aeruginosa 1822, anaerobic transfer of antibiotic resistance to recipients P. aeruginosa PS8EtBr and PS8EtBrR occurred at frequencies of 6.2 x 10(-9) and 5.0 x 10(-8) cells per plaque-forming unit, respectively. In experiments performed outside the isolator, transfer frequencies to PS8EtBr and PS8EtBrR were higher, 1.3 x 10(-7) and 6.5 x 10(-8) cells per plaque-forming unit, respectively. When P. aeruginosa 1822 was incubated aerobically with Escherichia coli B in medium containing nitrate and nitrite, the maximum concentration of carbenicillin-resistant E. coli B reached 25% of the total E. coli B population. This percentage declined to 0.01% of the total E. coli B population when anaerobically grown P. aeruginosa 1822 and E. coli B were combined and incubated in the glove box isolator. The highest concentration of the recipient population converted to antibiotic resistance occurred after 24 h of aerobic incubation, when an initially high donor/recipient ratio (>15) of cells was mixed. These data indicate that transfer of antibiotic resistance either by transduction between Pseudomonas spp. or by conjugation between Pseudomonas sp. and E. coli occurs under strict anaerobic conditions, although at lower frequencies than under aerobic conditions.     

Antibiotic utilization and Pseudomonas aeruginosa resistance in intensive care units

Pseudomonas aeruginosa is one of the most frequent and dangerous pathogens involved in the etiology of severe nosocomial infections. A retrospective observational study was conducted at all intensive care units of the University Hospital in Olomouc, Czech Republic (155 ICU beds). Complete antibiotic utilization data of the ICUs in the period of 1999 to 2008 were processed according to ATC/DDD system and expressed in defined daily doses per 100 bed-days (DBD). Utilization of meropenem, imipenem, ciprofloxacin, ofloxacin, pefloxacin, gentamicin, amikacin, ceftazidime, cefoperazone, cefoperazone/sulbactam and piperacillin/tazobactam was measured. Pseudomonas aeruginosa strains were isolated from clinical material obtained from patients hospitalized in ICUs. During the ten-year period, utilization of the entire group of antibiotics monitored grew. It increased from 23.52 DBD in 1999 to 27.48 DBD in 2008 with a peak of 33.04 DBD in 2007. P. aeruginosa accounted for as much as 42% of pneumonias and 23% of surgical wound infections. Our results show that P. aeruginosa strains became gradually resistant to all antibiotics used in the treatment of the infections caused by them, with the exception of amikacin and piperacillin/tazobactam.     

Epidemiological features of hospital purulent-septic infections in otolaryngological wards]

Prospective epidemiological observation in an otorhinolaryngological hospital has made it possible to distinguish the specific features of pyoseptic nosocomial infections. Such infections, appearing as cross re- and superinfections, are most frequently induced by staphylococci, as well as by Proteus and Pseudomonas aeruginosa. High risk groups include patients with purulent otitis and sinusitis, who have contacted infection through instruments in examination and dressing rooms. The main sources of infection are patients with pyoseptic infections of the ear and sinuses.     

Administration of antibiotics in combination. The antibacterial activity of blood serum and urine after a simultaneous administration of aminoglycosides and ampicillin

Blood serum and urine samples collected from a group of volunteers treated with single doses of ampicillin and aminoglycoside preparations given separately or in combination were tested for their antimicrobial activity against the reference strains Staphylococcus aureus SZK 76/69 and ATCC 6538, Pseudomonas aeruginosa SZK 444 and SZK 385, and Escherichia coli SZK 326/71. Out of all antimicrobials and their combinations tested the most powerful was the combination of netilmicin with ampicillin. Of the therapeutic combinations used nowadays in clinical practice the combined use of gentamicin and ampicillin proved also effective. These antibiotic combinations appear thus to be best suited for the treatment of mixed Pseudomonas aeruginosa and Staphylococcus aureus infections and of urinary tract infections caused by bacterial strains exhibiting in the in vitro susceptibility assays a reduced sensitivity to some of the antibiotic preparations used.     

Offline Controlling of Pseudomonas aeruginosa Resistant to protein Inhibitor Antibiotics Using Combination of EDTA and Na- citrate or Disinfectant (s)

P·aeruginosahave a number of virulence factors like extracellular toxins[1], protea-ses[2,3], haemolysins[4,5], and exopolysaccharide[6,7], which adapt the infection of specifichost tissues[8], causing severe problems·P·aeruginosacan survive in a numbe…     

What can Dictyostelium bring to the study of Pseudomonas infections?

Bacterial infections are complex events. They are studied in a variety of simple model systems, using mammalian or non-mammalian hosts, all of which fail to reproduce fully the situation in infected patients. Each model presents a combination of conceptual, practical, and ethical advantages and disadvantages. In this review, we detail the use of Dictyostelium discoideum amoebae as a model to study Pseudomonas aeruginosa. More specifically, our aim is to explore what this additional model system can bring to our understanding of Pseudomonas infections. The study of interactions between Dictyostelium amoebae and Pseudomonas provides a view of the selection pressures exerted by environmental predators on Pseudomonas. It also represents a unique system to assess the virulence of very large numbers of Pseudomonas strains.     

Factors influencing the adhesive properties of Pseudomonas aeruginosa

The aim of this study was to evaluate different factors which may influence surface and adhesive properties of Pseudomonas aeruginosa strains isolated from patients with urinary tract infections. P. aeruginosa strains exhibited moderate surface hydrophobicity as shown by "salting out" with ammonium sulfate and hydrophobic interaction chromatography. The ability to haemagglutinate red blood cells by P. aeruginosa strains was increased when the cells were treated with papain and neuraminidase. The ability of all tested strains to attach to plastic and glass surfaces was independent on incubation temperature. There was no significant difference in the ability of any particular P. aeruginosa strains to adhere to Vero cells in culture. In this study no correlation between hydrophobic properties, intensity of haemagglutination, and ability to attach to Vero cells in culture was observed.     

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.