Antibiotic sensitivity of different antigenic variants of Pseudomonas aeruginosa isolated in a hospital

The serological typing of 96% of P. aeruginosa strains isolated in hospitals has been carried out by means of agglutinating sera, and the tendency towards the prevalence of the strains of group V (25.3%) and serovar O11 (18.1%) has been revealed. The determination of the antibiotic sensitivity of different variants has shown that the strains of groups I, V and serovar O11 possess pronounced resistance to a wide spectrum of antibiotics, their resistance to gentamycin and polymixin being higher than in the strains of other serotypes. The determination of antibiotic resistance can serve only as an additional test in the serological typing of P. aeruginosa.     

An O-antigen study of Pseudomonas aeruginosa from serological group O11]

In the study of P. aeruginosa cultures, serogroup O11, strains agglutinated simultaneously by factor sera 11b and 11c have been detected. In experiments on cross agglutination and agglutinin adsorption the antigenic structure of these strains, viz. 11a, 11b and 11c, has been determined.     

The serological characteristics of the O antigens of Pseudomonas aeruginosa isolated from patients with a Pseudomonas infection during immunotherapy]

Serologic characteristics of P. aeruginosa O-antigens isolated from patients with P. aeruginosa infection were studied over the course of treatment with anti-P. aeruginosa sheep immunoglobulin. The preparation was used in 54 patients with nongeneralized forms of P. aeruginosa infection (infected wounds, pleural empyema) externally or intraperitoneally. From the clinical material collected from the patients a total of 54 P. aeruginosa strains were isolated. Serologic typing of the isolated strains with factor or group diagnostic agglutinating sera has revealed the O-group composition of the isolated strains; 66% of them were classified with O-groups 2,3, and 6. Serologic variants of the strains isolated from patients proved to be stable over the course of the disease immunotherapy. Analysis of the results of bacteriologic control of immunotherapy. efficacy and the clinical data has demonstrated the efficacy of immunotherapy in 61.1% of cases and its partial effect in 20.4% of cases of P. aeruginosa infection.     

Experience with epidemiologic studies of pyocyaneus infections. I. Feasibility of using serotypes and antibiotic resistance as a epidemiologic label for clinical strains]

The authors carried out serological typing of 98 Pseudomonas aeruginosa strains, isolated from patients of burn department of the Sklifosovsky First Aid Institute in January-July, 1974, and of 215 strains obtained from other sources; their sensitivity to 13 antibiotics was determined. Pseudomonas aeruginosa cultures isolated from the patients were typed with O-sera of 10 serological types. The presence of several hospital strains of Pseudomonas aeruginosa was found by means of serological typing; along with these there were revealed cultures of this causative agent sporadically appearing in the department. Sensitivity to some antibiotics could serve as an additional criterion for differentiation of Pseudomonas aeruginosa strains of the same serological type.     

Prevalence of Pseudomonas aeruginosa O serogroups

The serological typing of 708 P. aeruginosa strains made it possible to determine serogroups in 97.9% of cultures. Serogroups O2 and O6 were the most prevalent (33.8% and 2.5% respectively); serotypes O1, O3 and O11 also occurred rather frequently (about 10%); O4, O7 and O9 were rare (3-8%), serotypes O10 and O12, very rare (less than 1%). The prevalence of P. aeruginosa strains O2 and O6 among the clinical strains was shown over a period of 10 years, serogroup O2 always playing the leading role. In serogroups, the predominance of strains with a definite combination of partial antigen was established; strains with the antigenic structure not described in the International Scheme of the Structure of O-Antigens were detected.     

Detection of microbial surface antigens that bind Lewisa antigen

Abstract There is evidence that the Lewis^a blood group antigen is one of the receptors for a number of potentially pathogenic microorganisms. To determine how widely distributed the microbial adhesins are that bind this antigen, anti-idiotypic antibodies produced against monoclonal anti-Lewis^a were used in coagglutination assays to screen a variety of species. The following were agglutinated: 7/7 strains of Staphylococcus aureus ; 10/19 (53%) strains of Neisseria meningitidis ; 8/13 (62%) strains of Haemophilus influenzae ; 1/3 strains of Helicobacter pylori ; 1/2 strains of Neisseria gonorrhoeae ; 1/2 strains of Candida albicans . The application of the anti-idiotypic antibodies to studies of host cell receptors, isolation of adhesins and development of new epidemiological typing reagents is discussed.     

Conservation of components of the Escherichia coli export machinery in prokaryotes

Esterase electrophoretic typing was used to classify clinical isolates of Pseudomonas aeruginosa. One hundred and twenty-seven P. aeruginosa strains belonging to 16 serotypes (including 16 non-typeable strains) and isolated from diverse human infections in three hospitals, and the type strain ATCC 10 145, were tested. Four main kinds of esterase and 4 additional esterases were distinguished by their spectra of hydrolytic activity toward synthetic substrates and by their sensitivity or resistance to di-isopropyl fluorophosphate. The electrophoretic variations of these enzymes were used to define 42 zymotypes. Electrophoretic typing of esterase appeared to be more sensitive than serotyping and the results of the two methods did not correlate. When the two typing methods were used in parallel, 78 different combinations of serotype and zymotype were obtained.     

PCR-RAPD typing of carbapenem-resistant Pseudomonas aeruginosa strains

P. aeruginosa rods are opportunistic pathogens responsible generally for nosocomial infections. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to evaluate the usefulness of PCR-RAPD technique in typing of 16 carbapenem-resistant P. aeruginosa strains isolated in 2007 from different patients of University HospitalNo. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Study shows increasing frequency of isolation that type of strains when compared to 2006. Percentage of carbapenem-resistant isolates raised from 12,4% in 2006 to 22.9% in 2007. The majority of examined strains were obtained from patients of the Intensive Care Units (25.0%) and were isolated from bronchoalveolar lavage (25.0%), urine (25.0%) and wound swabs (18.8%) samples. Examined P. aeruginosa strains demonstrated resistance to doripenem (81.3%) and piperacillin (75.0%) and susceptibility to colistin (100.0%), amikacin (81.3%), netilmicin and norfloxacin (75.0% each). Using PCR-RAPD amplification with 208 and 272 primers, 14 and 16 DNA patterns were obtained, respectively. Usefulness of PCR-RAPD in carbapenem-resistant P. aeruginosa strains typing was proved in case of strains presenting similar and/or different antimicrobials susceptibility patterns.     

Pathogenicity factors of melanin-forming strains of Pseudomonas aeruginosa

The data on the capacity of 50 melanogenic and 50 amelanogenic P. aeruginosa strains to produce hemolysins, gelatinase, caseinase, DNAase, RNAase, lecithinase, elastase, neuraminidase and to form extracellular slime, obtained in the comparative study of these strains in vitro, are presented. Melanogenic P. aeruginosa cultures were found to have a higher lecithinase and neuraminidase activity. The strains incapable of melanogenesis formed slime more frequently. The properties of the strains in respect to other pathogenicity characteristics under study were identical.     

Characterization by pyocine typing and serotyping of oral and sputum strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients

Oral and sputum isolates of Pseudomonas aeruginosa in patients with cystic fibrosis were investigated. Of the 17 patients studied, 12 patients (71%) yielded both mucoid and nonmucoid variants of Pseudomonas aeruginosa from sputum and (or) various oral ecological sites, such as buccal mucosa, tongue dorsum, dental plaques, and saliva. A total of 51 strains of mucoid and nonmucoid Pseudomonas aeruginosa were isolated from these patients and were phenotypically characterized by both pyocine typing and serotyping. Five patients (42%) were colonized or infected by a single strain of Pseudomonas aeruginosa, whereas 7 patients (58%) were cocolonized or coinfected by two or more phenotypically different strains of Pseudomonas aeruginosa. To understand the mechanisms involved in Pseudomonas aeruginosa colonization, it may be necessary to identify multiple isolates of Pseudomonas aeruginosa not only from the sputum but also from the various oral ecological sites and to further explore the role of the oral cavity in this colonization.     

Heat-stable somatic antigens of a group of unclassified fluorescent pseudomonads (UFP).

(i) Isolates belonging to a group of unclassified fluorescent pseudomonads (UFP) are similar to Pseudomonas aeruginosa not only in cultural behaviour but also in basic serological properties of their somatic antigens. Living bacteria and cultures subjected to prolonged heating at 100 degrees C or above agglutinated readily in homologous O serum, whereas after exposure to 60 degrees C, ethanol, saturated sodium chloride and formalin the cells of both species became practically inagglutinable. Surface factors inhibiting the agglutination of living bacteria in O sera being absent, the slide technique was chosen as a routine method for the serological grouping of UFP. (ii) The O antigens of UFP were different in serological specificity from those of P. aeruginosa: the two organisms were related only by minor "common" antigens detectable with bacteria heated at 130 degrees C. One hundred and ten out of 115 UFP isolates were classified into 17 serological groups; O groups 2, 5, 10, 12 and 16 were each further divided into two subgroups. Five isolates reacted in several sera or were unstable. (iii) Serological grouping of UFP is reproducible and adequate for the tracing of isolates and may be helpful for a rapid differentiation of the organism from P. aeruginosa.     

Routes of the transmission of Pseudomonas aeruginosa infection in resuscitation and intensive therapy departments

To find out if the transfer of P. aeruginosa infection by droplet route is possible in resuscitation and intensive care units, the bacteriological study of air samples taken in different rooms of resuscitation units (altogether 234 air samples) was carried out with the subsequent identification and typing of isolated P. aeruginosa strains. In most cases (70.5%) the microbial contamination of the air in the main rooms of resuscitation units was found not to exceed 500 microbial cells per cu. m, and no P. aeruginosa strains were isolated. The identification and typing of six P. aeruginosa strains isolated from the air of an isolation ward for patients with infectious complications made it possible to find out intraspecific differences of these microorganisms, as all of them belonged to strains of different sero- and pyocinotypes. Thus, the results of these investigations indicate that the droplet route of the transfer of P. aeruginosa hospital infection is not characteristic of resuscitation and intensive care units, as no P. aeruginosa strains are isolated from the main rooms of such units; likewise, no circulation of this microorganism was observed in the air of an isolation ward for patients with infectious complications.     

Classification of 17 newly isolated virulent bacteriophages of Pseudomonas aeruginosa

Seventeen virulent bacteriophages specific to Pseudomonas aeruginosa strains were isolated by screening various environmental samples. These isolated bacteriophages were grouped based on results obtained from restriction fragment analysis of phage genomes, random amplification of polymorphic DNA (RAPD) typing, morphology observations under transmission electron microscope, and host range analysis. All 17 bacteriophages are double-stranded DNA viruses and can be divided into 5 groups based on DNA restriction profiles. A set of 10-mer primers was used in RAPD typing of phages, and similar conclusions were obtained as for restriction fragment analysis. One phage was randomly selected from each of the 5 groups for morphology observations. Four of them had an icosahedral head with a long contractile tail, belonging to the Myoviridae family, and one phage had an icosahedral head with a short tail, thereby belonging to the Podoviridae family. Host range experiments were conducted on 7 laboratory strains and 12 clinical strains of P.?aeruginosa. The results showed that 13 phages had the same infection profile, killing 8 out of 19 tested P.?aeruginosa strains, and the remaining 4 phages had different and unique infection profiles. This study highlights the diversity of bacteriophages specific to P.?aeruginosa in the environment.     

Immunologic study of the cellular components of bacillus pyocyaneus. V. Antigenic analysis of slime and its fractions]

Various slime fractions were obtained from newly isolated mucoid strains of P. aeruginosa by the method of ultrafiltration or differential centrifugation with subsequent gel chromatography. Purified slime was found to react with a broader spectrum of typing O sera than the corresponding cell wall lipopolysaccharides. Erythrocytic diagnostic preparations produced on the basis of slime antigens allowed to reveale the presence of circulating antibodies against P. aeruginosa. The slime components with molecular weight of 30,000--100,000 daltons and greater contained common antigenic determinants, and the slime components with molecular weight of 10,000--30,000 daltons contained both specific antigenic determinants and those also common to the high molecular components.     

Genetic characterization of atypical Shigella flexneri isolated in Korea

Three types of serotypically atypical Shigella flexneri strains were isolated from 2007 to 2008 in patients at the Korea National Institute of Health (NIH). These strains were characterized and compared with serologically typical S.flexneri. One type of strain either displayed nonreacting typing or grouping sera, reacting strongly only with polyB antisera, which indicates this strain is S. flexneri (polyB:un). The second type displayed reactions with one of the typing sera (IV) and did not bind any grouping sera (IV:un). The remaining type of strain displayed a plural agglutination pattern, reacted with one typing sera (II), and bound with two grouping sera (II:(3)4,7(8)). Among these atypical strains IV:un and II:(3)4,7(8) strains showed higher multi-antibiotic resistance in ampicillin, streptomycin, and trimethoprim-sulfamethoxazole than typical strains. Furthermore, all II:(3)4,7(8) strains harbored integrons. This study suggests that these multiple antibiotic-resistant atypical S. flexneri are new subserotypes of S.flexneri that await further serological classification.     

Typing of Streptococcus group A isolated from patients and healthy persons

The typing of 80% of 381 streptococcal strains, group A, under study was accomplished with a set of diagnostic anti-T sera obtained from the Sevak Institute (Czechoslovakia). None of the T-types could be related with certainty to the localization of the infective agent in the human body (the pharynx, the skin). Different T-types were shown to circulate in definite regions of the USSR. To enhance the differentiating capacity of T-typing, the enzymatic (lipoproteinase and NADase) activity of the strains was determined, thus permitting the subdivision of the T-types into still smaller groups. The typing of OF+ strains of unknown M-specificity could be carried out by means of the blood sera of healthy persons, containing antibodies to streptococcal lipoproteinase. The conclusion on the expediency of using the determination of lipoproteinase and NADase as an additional marker in the typing of group A streptococci was made.     

Pyocin production by bacillus pyocyaneus and sensitivity of strains of different origin to them

Using the method proposed by Gillies and Govan and their indicator strains, 342 P. aeruginosa strains isolated from the patients were studied in respect to their pyocinogenicity and typed according to the production of different types of pyocins. Besides, in 206 cultures the pyocin sensitivity of 16 standard P. aeruginosa strains (5 strains obtained from Govan and 11 strains provided by the authors) was determined. All the tested cultures fell into 23 pyocin types; of these, types I and X occured most frequently, 56 strains identified by means of indicators could not be typed due to the fact that the corresponding pyocin types were absent in Govan's scheme. The cultures isolated from the patients and the environmental objects during the outbreak of P. aeruginosa in a hospital were proved to belong to the same pyocin type (III). The double typing of the cultures, according to pyocin production and pyocin sensitivity, allowed to determine individual characteristics of 75% of the tested cultures.     

Influence of Iron on Yields of Extracellular Products in Pseudomonas aeruginosa Cultures

The effect of the iron content of the medium on the yields of extracellular products by seven distinct strains of Pseudomonas aeruginosa was examined. All strains showed at least an 85% decrease in toxin A yields when grown in medium containing 5.0 mug of iron per ml (high iron) as compared to 0.05 mug/ml (low iron), whereas bacterial growth increased approximately twofold. During the course of examining extracellular products produced by P. aeruginosa, we found many strains that produced an extracellular factor which agglutinated erythrocytes. This hemagglutinin was nondialyzable, heat stable, and resistant to Pronase and trypsin. The effect of iron on extracellular yields of hemagglutinin was strain dependent; four of seven strains showed decreases in hemagglutinin yields in high-iron medium. Similarly, the effect of increasing the iron concentration of the growth medium on yields of total extracellular proteases or on elastase was strain dependent. The amount of total extracellular protein was decreased by at least 31% in the high-iron medium for all strains of P. aeruginosa examined. Detailed studies on one strain (WR-9) showed that, in the presence of increasing amounts of iron in the medium, the extracellular yields of toxin A, protease, and hemagglutinin were decreased in a similar manner. In addition, the kinetics of release of these extracellular products were similar at a given iron concentration. Thus it appears that the yields of other extracellular products of P. aeruginosa besides toxin A are influenced by the concentration of iron in the growth medium.     

Pyocin Typing of Pseudomonas aeruginosa: a Simplified Method

A simplified method has been devised for typing Pseudomonas aeruginosa by pyocin production. Pyocins are produced as strains grow overnight in Trypticase soy broth (without glucose) plus 1% potassium nitrate. Because P. aeruginosa can use nitrate instead of oxygen as a terminal electron acceptor, mechanical shaking is not necessary, nor is induction by mitomycin C. Pyocins can now be produced in screw-cap tubes in a water bath or incubator. A total of 250 strains were tested as possible pyocin indicators, which included 60 strains already used in pyocin-typing systems. The final set contained 18 indicators which were chosen because (i) they had clear positive or clear negative reactions, thus eliminating reactions difficult to read, (ii) they had few zones due to bacteriophage lysis, and (iii) they were most sensitive in differentiating clinical isolates of P. aeruginosa. The final typing method was tested in several studies and the results were clear; thus definitive epidemiological conclusions could be made. Because it is simple to perform and easily automated, the new method should have application in many hospitals; however, it should be used only in carefully planned epidemiological studies. The method and its application are described in detail, and some pitfalls are discussed.     

Arbitrary primed PCR fingerprinting and serotyping of clinical Pseudomonas aeruginosa strains

Arbitrary primed PCR (AP-PCR) analysis was compared with serotyping as a means of high-resolution typing of Pseudomonas aeruginosa. Seventy-four isolates from 3 different hospitals and 18 reference strains were studied. Serotyping provided good index of discrimination, although eleven isolates could not be serotyped. Genomic DNA was amplified with a single 10 nucleotide primer (sequence 5′-AGG GGT CTT G-3′). The strains were genetically diverse and 61 different AP-PCR profiles of 2–7 bands between 0.3 and 2.4 kb were obtained. AP-PCR profiles were not consistently associated with serotypes, but they clearly subtyped strains of the same serotype. Numerical analysis of AP-PCR patterns defined 7 groups at the 55% similarity level, and identified predominant strains in each hospital. The results show that AP-PCR analysis provides a simple and practical approach to typing P. aeruginosa that is more discriminatory than traditional serotyping scheme. We suggest that maximum discrimination can be achieved by a combination of both methods.