Gentamicin- and silver-resistant pseudomonas in a burns unit.

In 1977-8 gentamicin-resistant strains of Pseudomonas aeruginosa became very common in a burns unit, over 90% being resistant at the peak of the outbreak. Some strains were also resistant to silver nitrate, though silver resistance was not found in any other strains of Ps aeruginosa isolated. Unlike the gentamicin resistance, the silver resistance was unstable, and strains became sensitive on repeated subculture. All the gentamicin-resistant strains of Ps aeruginosa were of the same serotype (O:11, H:2,5). Though gentamicin resistance could be transferred in vitro from resistant strains of Ps aeruginosa to one sensitive strain of Ps aeruginosa, there was no evidence of in-vivo transfer of gentamicin resistance between strains of pseudomonas in the patients'' burns, nor was there evidence of transfer of gentamicin resistance between Ps aeruginosa and enterobacteria. Carbenicillin-resistant and gentamicin-resistant Ps aeruginosa were sometimes found in the same burns, but no gentamicin-carbenicillin (doubly) resistant strains were found among the 986 strains tested during the outbreak. The outbreak of gentamicin-resistant Ps aeruginosa from burns was not reduced by stopping treatment with gentamicin and its analogues but only by segregating all patients with Ps aeruginosa in one of the two wards of the unit and admitting new patients only to the other ward.     

Antibody response to P. aeruginosa in patients with cystic fibrosis: evaluation of two methods.

The immunological response to Ps. aeruginosa antigens may be a sensitive and early indicator of the colonisation of the lungs with these organisms in patients with cystic fibrosis. This study used an immunoenzymatic system and immunoblotting to evaluate the antibody response of 20 patients without apparent Ps. aeruginosa lung infection. These was an agreement in the results obtained with the two methods in 87.5% of cases.     

Antibiotic sensitivity of Proteus, Pseudomonas pyocyanea and staphyloccoci isolated from scleroma and ozena patients]

Antibiotic sensitivity of 292 strains of Proteus, 60 strains of Ps, aeruginosa, 309 strains of S. aureus and 88 strains of S. epidermidis isolated from the upper respiratory tract of patients with scleroma and ozena was studied. The cultures of Pr. mirabilis were sensitive to aminoglucosides (54.9-96.2 per cent) and Pr. morganii were sensitive to levomycetin (81.5 per cent) and neomycin (92.6 per cnet). Sensitivity of Pr. vulgaris and Pr. morganii was reliably higher (p less than 0.001) than that of Pr. mirabilis. The strains of Pr. morganii were less sensitive to monomycin (P less than 0.001) and streptomycin (p less than 0.01) as compared to the cultures of other Proteus species tested. The strains of Ps. aeruginosa were sensitive only to gentamicin (90 per cent) and neomycin (81.1 per cent). Most of the strains of S. aureus (85.4-100 per cent) were sensitive to oleadomycin, erythromycin, olemorphocycline, tetraolean, oxacillin, methicillin ceporin, lincomycin, ristomycin, kanamycin, monomycin and gentamicin. Benzylpenicillin (90.8 per cent of the sensitive strains), ampicillin (67.1 per cent), tetracycline (66.7 per cent), levomycetin (68.6 per cent) and streptomycin (38.1 per cent) were less effective. Antibacterial therapy in cases with scleroma and ozena should be directed not only against causative agents of the diseases but also against the microbes developing due to disbacteriosis. Combination of parenteral and local use of the antibiotics in the treatment of chronic clebsiellesis decreased the isolation rate of Proteus and Ps. aeruginosa in the patients.     

Typing of Pseudomonas aeruginosa strains in Turkish cystic fibrosis patients

The majority of cystic fibrosis (CF) patients suffer from chronic respiratory infection with the opportunistic bacterial pathogen Pseudomonas aeruginosa. The virulence of P. aeruginosa is associated with the presence of various extracellular factors, like alginate, elastase, alkaline protease which contribute tissue destruction and assist bacterial invasion. Virulence factor production of P. aeruginosa strains isolated from 46 CF patients followed in two cities in Turkey was detected. Strains were compared genotypically by arbitrarily primed PCR. Antimicrobial susceptibilities to 12 antibiotics were determined by broth microdilution method. Evaluation of virulence factor results revealed that 95.8% of the strains were alginate, 71.7% elastase and 52.1% alkaline protease producers. AP-PCR analysis revealed 35 genotypes indicated almost a complete discrepancy among the strains. The most effective drugs were penems and quinolones. Among aminoglycosides amikacin was the most effective one and a high level resistance to beta lactams was observed. Alginate is the most important virulence factor in the chronic colonisation of CF patients with P. aeruginosa. No evidence for cross infection between patients and for relationship between phenotypes and genotypes of the strains was found.     

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.     

Nosocomial transmission of group B streptococci.

The acquisition of group B streptococci by babies in a special-care baby unit and two postnatal wards was investigated over a six-month period using serology and phage typing. Sixty-three culture-positive babies were identified in the postnatal wards, one-third of whom had been born to mothers who were not carrying the organism in the genital tract or anorectal area during labour. A non-maternal source was identified for 14 of these 21 infants: either colonised mothers and babies in the same ward or, on one occasion, a member of the hospital staff. In the special-care baby unit, however, only one instance of nosocomial acquisition of group B streptococci was recorded despite a high prevalence of colonisation in the staff on the unit and the presence of heavily colonised babies. The results of this survey suggest that although sepsis caused by group B streptococci may be the result of nosocomial transmission, this may be prevented by careful attention to hygiene.     

Comparison of some adhesive properties of Pseudomonas aeruginosa strains isolated from respiratory and urinary tract infections

The aim of the paper was the comparison of adhesive properties concerning pathogenic potential of P. aeruginosa strains isolated from the patients with respiratory tract infections and from the patients with urinary tract infections. It was stated that P. aeruginosa strains had no haemagglutinating properties when cultured on a solid medium. Bacteria cultured in a liquid medium showed an increase of these properties in 48 h cultures as compared with 24 h cultures. They were not sensitive to heating. The haemagglutinating properties of the most strains were inhibited by D-mannose. These results seem to suggest that in P. aeruginosa strains fimbriae play an important role in adhesion. On the other hand, the mechanism of adhesion is not uniform as shows mannose-sensitivity of some strains and its lack in the other haemagglutinating strains. The most effective agglutination of human erythrocytes seems to be caused by the species specificity of the individual strains isolated from humans. The higher attachment of P. aeruginosa strains isolated from the urinary tract infections than those from respiratory tract infections to "Vero" cells suggests that these two strains populations may differ in their pathogenic potential to various tissues.     

Pseudomonas aeruginosa antibody detection in cystic fibrosis patients.

Chronic respiratory infection due to Pseudomonas aeruginosa remains the most important prognostic factor in cystic fibrosis patients. One method to lengthen the patient's life is to extend the initial state of the illness with an early diagnosis, before Ps. aeruginosa infection becomes chronic. Often this is difficult because of the young age of the patients. This study tested an immunoenzymatic system to evaluate antibody response against three Ps. aeruginosa purified antigens, alkaline protease, elastase and exotoxin A. We studied 40 patients with cystic fibrosis, 20 affected and 20 unaffected by apparent Ps. aeruginosa infection, also from the bacteriological point of view. Serological and bacteriological results were compared for each patient and showed that serological screening can be useful in young subjects, who often have no bacteriological evidence of Ps. aeruginosa colonization.     

Serum IgG response to Burkholderia cepacia outer membrane antigens in cystic fibrosis: Assessment of cross-reactivity with Pseudomonas aeruginosa

Abstract Burkholderia cepacia (Pseudomonas cepacia) is now recognised as an important pathogen in cystic fibrosis patients, and several reports have suggested that sputum-culture-proven colonisation occurs despite the presence of specific antibody. In an attempt to establish the use of antibody studies as diagnostic and prognostic indicators of B. cepacia infection, we have examined the IgG response to B. cepacia outer membrane proteins and lipopolysaccharide in patients also colonised with P. aeruginosa . The B. cepacia strains were grown in a modified iron-depleted chemically defined medium and outer membrane components examined by SDS-PAGE and immunoblotting. IgG antibodies were detected against B. cepacia outer membrane antigens, which were not diminished by extensive preadsorption with P. aeruginosa . The response to B. cepacia O-antigen could be readily removed by adsorption of serum either with B. cepacia whole cells or purified LPS, whereas we were unable to adsorb anti-outer membrane protein antibodies using B. cepacia whole cells. The inability to adsorb anti-outer membrane protein antibodies using B. cepacia whole cells maybe due to non-exposed surface epitopes. Several B. cepacia sputum-culture negative patients colonised with P. aeruginosa had antibodies directed against B. cepacia outer membrane protein. This study suggests that there is a specific anti- B. cepacia LPS IgG response, which is not due to antibodies cross-reactive with P. aeruginosa . Our studies indicate that much of the B. cepacia anti-outer membrane protein response is specific and not attributable to reactivity against co-migrating LPS.     

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).     

Volunteer and clinical studies with carfecillin: a new orally administered ester of carbenicillin.

Blood and urine levels of carbenicillin were measured in 10 healthy volunteers and four patients with renal failure after single and multiple oral dose of carfecillin. Urinary levels after 1000-mg doses in healthy subjects were considered sufficient for treatment of Pseudomonas aeruginosa urinary infections, but the serum levels were too low for chemotherapy of systemic infections with this organism even in severe renal failure. Urinary infections were treated in 35 inpatients with a seven-day course of carfecillin. The infection was eradicated in 21 cases (60%). In 12 cases the pathogen was Ps. aeruginosa, which was eradicated from eight patients (67%). Many patients had severe urinary tract disease. Side effects were virtually absent.     

Investigations on the efficacy of monovalent Pseudomonas aeruginosa vaccine for oral administration in Pseudomonas aeruginosa experimental infection

Therapeutic efficacy of Pseudomonas aeruginosa vaccine for oral use (10(10) killed germs/ml), prepared from strain 4922, belonging to serotype XV, by Meitert-Meitert scheme, on 4 experimental models in mice (pneumonia, infected burn, septicaemia and urinary tract infection) was studied in comparison with monovalent Ps. aeruginosa vaccine serotype XV (10(9) killed germs/ml) for subcutaneous use and also with associated administration of the two vaccine variants. Mice immunization by using vaccine for oral use was performed by 0.5 ml vaccine per day, for 10 days and vaccine for subcutaneous use was administrated in a volume of 0.5 ml x 2, at 3 days interval. Mice immunization by using the two vaccine types, in association was concomitantly performed and in the same quantity as for separate immunization. In experimental pneumonia, Ps. aeruginosa vaccine for oral use protected mice in 35% of cases, those with infected burns were protected in 33.3% of cases, those with septicemia--in 96.6% of cases and those with urinary tract infection in 50% of cases. As compared to Ps. aeruginosa vaccine for subcutaneous use, the results obtained by vaccine for oral use are less favourable but associated administration of both vaccine variants led to superior results. Thus, in experimental pneumonia, it was obtained a surviving rate of 65% for animals immunized with both vaccine types, in comparison with 50% for animals immunized with vaccine for subcutaneous use only, and in Ps. aeruginosa infected burn, it was obtained a recovering rate of 79.1% for the animals immunized by using both vaccines, in comparison with 70.8% surviving for animals immunized with vaccine for subcutaneous use. In experimental septicaemia and urinary tract infection, combined use of both vaccine variants determined animals surviving and recovering in percents similar to those obtained by separate administration of vaccine for subcutaneous use (in septicemia--100% protection; in urinary tract infection--75% protection).     

Molecular characterization of Pseudomonas aeruginosa 2NR degrading naphthalene

Three naphthalene-degrading strains were isolated from compost, characterized by morphological and physiological properties and differentiated by 16S rDNA RFLP. During growth on naphthalene, Pseudomonas aeruginosa 2NR produced ortho catechol pathway intermediates and gentisic acid. The ability to accumulate and degrade gentisic acid shows that Ps. aeruginosa 2NR has a different salicylate pathway to that of the intensely studied Ps. putida NCIB 9816. Molecular analysis showed the presence both of genes of the upper naphthalene pathway and genes of the ortho and meta catechol pathways. The insertion of nagH and nagG, coding for salicylate 5-hydroxylase in Pseudomonas sp. U2, was absent in Ps. aeruginosa 2NR, as in Ps. putida NCIMB 9816.     

Comparative study of the biological characteristics of mucoid and non-mucoid Pseudomonas aeruginosa strains isolated from chronic respiratory infections

Morphological, culture and enzymatic characteristics, as well as virulence, susceptibility to antimicrobial agents and epidemiological markers, were studied for 100 mucoid and 100 non-mucoid Ps. aeruginosa strains isolated from chronic respiratory infections. For 10 mucoid and 10 non-mucoid strains was performed the active protection test in mice, both with inactivated germs (10(9) germs), and LPS extracted by Westphal method. It was ascertained that mucoid Ps. aeruginosa strains differ from non-mucoid strains by the slow growth on culture media, more reduced proteolytic activity (81% as compared to 99%), slow oxidation of carbohydrates (5-7 days), reduced virulence in mice (8%) or avirulence (92%), higher sensitivity to some antibiotics (amikacin, dibekacin, ticarcillin, tetracycline, cefotaxime, ceftriaxone), lysoresistance (74%) and polyagglutinability (67%). The mucoid strains ensure a reduced active protection in mice, 70% of strains did not protect the mice against the infection with virulent homologous strains, while the non-mucoid strains ensured 80%-100% protection.     

老年气管插管患者下呼吸道感染细菌分布及 耐药性分析

目的研究老年气管插管患者下呼吸道感染的病原菌分布及耐药情况,为临床插管前预防性经验用药提供参考。方法回顾性分析2014-2016年上海市虹口区江湾医院老年气管插管患者的病原菌分布及耐药性情况。结果 560例标本中共检出177株致病菌,其中革兰阴性杆菌121株(68.36%),以肺炎克雷伯菌、铜绿假单胞菌为主;除鲍曼不动杆菌/溶血不动杆菌外,其他革兰阴性杆菌对亚胺培南、美罗培南敏感性均较高。革兰阳性球菌检出52株(29.38%),以金黄色葡萄球菌为主(其中MRSA 37株),对万古霉素敏感性较高。另外分离到真菌4株。结论气管插管患者下呼吸道感染致病菌以肺炎克雷伯菌、铜绿假单胞菌、金黄色葡萄球菌为主。在临床应用中,应根据本地区、本医院的病原菌分布状况和细菌耐药情况,给予适当药物,预防感染。     

Use of ampicillin trihydrate in transplantation surgery]

Ampicillin trihydrate was used for the treatment of 29 patients with purulent inflammatory processes, such as peritonitis, suppurating operative wound, urinary tract infection after the kidney allotransplantation. The antibacterial activity of ampicillin was preliminarily tested on 517 microbial strains, i.e. staphylococci, streptococci, E. coli, Proteus and Ps. aeruginosa isolated from the surgical patients. The strains of penicillin sensitive staphylococci, streptococci and E. coli were most sensitive to the drug effect, the MIC ranging from 0.03 to 16 gamma/ml. It was shown that the blood retention time of the antibiotic was much more prolonged in the patients with a decreased excretion function of the kidneys. The treatment was performed under control of the clinical, bacteriological and biochemical parameters. The drug was used in a dose of 0.5 g 6--8 times a day for 5 to 15 days. A satisfactory therapeutic effect was registered in 73 per cent of the cases.     

The persistence of multifocal colonisation by a single ABC genotype of Candida albicans may predict the transition from commensalism to infection

Candida albicans is a common member of the human microbiota and may cause invasive disease in susceptible populations. Several risk factors have been proposed for candidaemia acquisition. Previous Candida multifocal colonisation among hospitalised patients may be crucial for the successful establishment of candidaemia. Nevertheless, it is still not clear whether the persistence or replacement of a single clone of C. albicans in multiple anatomical sites of the organism may represent an additional risk for candidaemia acquisition. Therefore, we prospectively evaluated the dynamics of the colonising strains of C. albicans for two groups of seven critically ill patients: group I included patients colonised by C. albicans in multiple sites who did not develop candidaemia and group II included patients who were colonised and who developed candidaemia. ABC and microsatellite genotyping of 51 strains of C. albicans revealed that patients who did not develop candidaemia were multiply colonised by at least two ABC genotypes of C. albicans, whereas candidaemic patients had highly related microsatellites and the same ABC genotype in colonising and bloodstream isolates that were probably present in different body sites before the onset of candidaemia.     

Pyocyaneus infection of burn wounds]

Materials of clinico-bacteriological study of 302 patients with thermal burns of different severity pointed to a considerable elevation of the incidence of Ps. aeruginosa isolation (in cultures) from burn wounds; the last few years it was found in about 50% of the cases. The greater frequency of Ps. aeruginosa detection correlated with the increase of the severity of the affection. By using Soviet set of 17 type agglutinating sera it was possible to type almost 90% of the Ps. aeruginosa cultures isolated from the wounds; a marked prevalence (over 70% of the strains) of cultures belonging to the serological group II was revealed. Patients admitted to the burn centre at early periods after the trauma displayed infection of the wound with the Ps. aeruginosa strain of the II serological group.     

Conjugation transfer of plasmid resistance to gentamycin and other antibiotics in clinical strains of Ps. aeruginosa]

A possibility of conjugation transfer of the markers of the plasmid resistance to gentamicin and other antibiotics from 10 clinical strains of Ps. aeruginosa, isolated from burn patients to the recipient strain of Ps. aeruginosa PTO 629 Rfr was shown. The marker of gentamicin resistance was transferred to 100 out of 110 of the exconjugants, i.e. 86.2 per cent. The rate of the conjugation transfer in the crosses between the clincal strains of Ps. aeruginosa and the recipient strain PTO 629 Rfr with respect to the gentamicin marker was about 10--7. The plasmid resistance markers in the clincal strains Ps. aeruginosa were transferred in various combinations. Transfer of the markers of resistance to streptomycin, carbenicillin, neomycin and combinations Sm, Nm and Sm, Nm, Cm was not achieved.     

Inhibition of adhesion to buccal epithelial cells of Pseudomonas aeruginosa by dextran

Adhesion of Pseudomonas aeruginosa strains to buccal epithelial cells appears to be a necessary precondition for colonization and infection of respiratory tract. There are many strategies to prevent host organisms for Pseudomonas aeruginosa. The purpose of these studies was to evaluate the potential for preventing adhesion of Pseudomonas aeruginosa to epithelial cells with dextran. Dextran (5,000 MW) inhibited adhesion of Pseudomonas aeruginosa to buccal cells, at 20 mM was most inhibitory. The inhibitory effect appeared to be nonspecific because other neutral polysaccharides (glycogen and mannan) were also inhibitory. Dextran is an inexpansive and nontoxic agent and may be useful to prevent colonization and infection of respiratory tract with Pseudomonas aeruginosa.