Plasmid Patterns Research Articles

The role of plasmids in opsonin-independent staphylococcus aureus-leukocyte interactions

The opsonin-independent phagocytic and bactericidal activity of human polymorphonuclear leukocytes stimulated by two Staphylococcus aureus strains and their variants with differing plasmid patterns was investigated. Interactions between staphylococci and phagocytes were evaluated by chemiluminescence and intracellular killing tests. The results obtained indicate that the presence or absence of certain plasmids can modify staphylococcal phagocytosis and their susceptibility to intracellular killing. Pretreatment of the strains investigated with subinhibitory concentrations of mezlocillin and ofloxacin (10% MIC) influenced these parameters, too.

Plasmid analysis as an epidemiological tool in neurosurgical infections with coagulase-negative staphylococci.

Coagulase-negative staphylococci isolated from blood or spinal fluid during a period of 1 year in a department of neurosurgery, were analysed by biotyping, antibiotic resistance pattern and plasmid profiles. Altogether 41 isolates from 19 patients were studied. About 90% of the isolates were Staphylococcus epidermidis. The antibiotic resistance pattern seemed to be closely related to antibiotic usage in the unit. Most common was resistance to penicillin (63%), trimethoprim-sulphamethoxazole (49%) and cloxacillin (39%) while resistance to gentamicin was seen in only one strain. In several cases species and antibiograms were identical in isolates from different patients. Plasmid pattern analysis could then be used for identification of different strains. In one instance, plasmid pattern and restriction enzyme analysis confirmed that two patients probably were infected by the same strain.

Antibiotic resistances and plasmids in Staphylococcus aureus from Italian hospitals.

A total of 473 Staphylococcus aureus isolates from six Italian hospitals was examined for susceptibility to several antimicrobial agents and for plasmid content. Methicillin-resistant S. aureus (MRSA) were characterised by a plasmid of mol. wt (10(6)) 18-22 or 25 that carried the determinants for penicillinase production, resistance to cadmium ions and resistance to tetracycline. MRSA isolates usually harboured other smaller plasmids of mol. wt (10(6)) 2.8, 2.6 and 1.65 that encoded resistance to tetracycline, chloramphenicol and erythromycin, respectively, and cryptic plasmids of mol. wt (10(6)) c. 2 and 1 were found frequently. Methicillin-sensitive S. aureus (MSSA) that produced penicillinase often carried plasmids of mol. wt (10(6)) 11 or 13. No particular difference was found in plasmid patterns of strains from the various sources. Analysis of plasmids by EcoRI digestion showed that plasmids of similar mol. wt and phenotypic characteristics may have different restriction patterns, but often share one or more fragments in common.

Alteration of surface properties in a Tn5 mutant strain of Rhizobium trifolii 0403.

A symbiotically defective mutant strain of Rhizobium trifolii, UR251, was obtained by transposon Tn5 mutagenesis of R. trifolii 0403 rif and recognized by its partially ineffective (Fix +/-) phenotype on white clover plants. UR251 had a single Tn5 insertion in plasmid DNA, a wild-type plasmid pattern, and no detectable Mu DNA sequences originally present in the vector used for Tn5 mutagenesis. Agglutination by the clover lectin trifoliin A and attachment to clover root hairs was higher with UR251 than with the wild-type strain. The capsular polysaccharide (CPS) of UR251 was altered, as shown by a slower rate of CPS depolymerization with a CPS beta-lyase, PD-I; more pyruvate and less acetate and 3-hydroxybutanoate noncarbohydrate substitutions as quantitated by 1H nuclear magnetic resonance; and a higher pyruvyl transferase activity (enzymatic pyruvylation of lipid-bound saccharides). The site of increased pyruvylation in the CPS of UR251 was on the terminal galactose of the branch of the repeating oligosaccharide unit. These results show that the level of noncarbohydrate substitutions of the CPS as well as pyruvyl transferase activity are altered in R. trifolii UR251 and that trifoliin A-binding ability and clover root hair attachment are improved in this mutant strain of R. trifolii 0403 rif.

Limitations of using the plasmid pattern as an epidemiological tool for clinical isolates of Shigella sonnei.

Journal Article Limitations of Using the Plasmid Pattern as an Epidemiological Tool for Clinical Isolates of Shigella sonnei Get access David Prado, David Prado Program in Infectious Diseases and Clinical Microbiology, Departments of Pediatrics and Internal Medicine, University of Texas Medical School at Houston, Houston, Texas Search for other works by this author on: Oxford Academic PubMed Google Scholar Barbara E. Murray, Barbara E. Murray Program in Infectious Diseases and Clinical Microbiology, Departments of Pediatrics and Internal Medicine, University of Texas Medical School at Houston, Houston, Texas Please address requests for reprints to Dr. Barbara E. Murray, Program in Infectious Diseases and Clinical Microbiology, University of Texas Medical School, 6431 Fannin Street, Houston, Texas 77030. Search for other works by this author on: Oxford Academic PubMed Google Scholar Thomas G. Cleary, Thomas G. Cleary Program in Infectious Diseases and Clinical Microbiology, Departments of Pediatrics and Internal Medicine, University of Texas Medical School at Houston, Houston, Texas Search for other works by this author on: Oxford Academic PubMed Google Scholar Larry K. Pickering Larry K. Pickering Program in Infectious Diseases and Clinical Microbiology, Departments of Pediatrics and Internal Medicine, University of Texas Medical School at Houston, Houston, Texas Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 155, Issue 2, February 1987, Pages 314–316, https://doi.org/10.1093/infdis/155.2.314 Published: 01 February 1987 Article history Received: 22 May 1986 Revision received: 06 August 1986 Published: 01 February 1987

Strategies for typing and properties of epidemic methicillin-resistant Staphylococcus aureus.

Isolates of 17 strains of epidemic methicillin-resistant Staphylococcus aureus from outbreaks in ten hospitals in the UK were investigated with a variety of techniques both to explore their properties and to type them in order to confirm or refute known or suspected epidemiology. The techniques consisted of a biotyping system, peptidoglycan analysis, testing of antibiotic sensitivity to 21 agents, various phage-typing methods including heat shock, plasmid pattern analysis, and heat cure derivation of plasmid-less isogenic strains. All strains resembled those originally isolated in Australia, being in the possession of a large number of chromosomal resistance factors, pigmentation, ability to produce lipase and large molecular weight plasmids (c.15 Md to c.23 Md) which conferred resistance to gentamicin, propamidine, ethidium bromide, cetrimide and chlorhexidine. Some strains also had a c.3 Md plasmid conferring chloramphenicol resistance and others a c.1 Md cryptic plasmid. A large percentage of the population was resistant to 25 mg/l methicillin at 37 degrees C, an unusual feature. All the strategies, with the exception of peptidoglycan analysis, contributed to typing of the strains.

Comparative Investigations of Klebsiella Species of Clinical Origin: Plasmid Patterns, Biochemical Reactions, Antibiotic Resistances and Serotypes

A total of 124 K. pneumoniae and 52 K. oxytoca isolates obtained from clinical specimens was investigated for plasmid patterns, biochemical reactions, antibiotic resistances and serotypes regarding to the distribution and relationships of these characters. A great diversity of plasmid patterns, bio/serotypes and resistance patterns was revealed. About 90% of strains contained plasmid DNA and up to seven plasmid bands per isolate could be shown. For K. pneumoniae, serotype 7 and for K. oxytoca, type 55 were most common. In general, little difference between both species was found and characters were similarly distributed. With respect to the site of isolation, serotype 7 was predominating in K. pneumoniae strains from the respiratory tract. Highly multiple-resistant organism were found in the largest number in specimens from the urogenital tract, in the lowest in specimens from wounds. Extensive statistical analyses did not detect any relationship among the characters investigated.

Plasmids as epidemiologic markers in nosocomial gram-negative bacilli: experience at a university and review of the literature.

Bacterial plasmids have become valuable markers for the comparison of strains of nosocomial gram-negative bacilli. The importance of plasmids in nosocomial infections is primarily due to their transferable antibiotic resistance genes (R plasmids), but other plasmid-mediated traits may eventually serve as potential markers. Stable cryptic plasmids have also served to relate outbreak strains, particularly nonfermenting strains of gram-negative bacteria. Klebsiella pneumoniae and Serratia marcescens have been the major plasmid-containing species in outbreaks involving single or multiple species. Outbreaks of single species with common plasmid patterns have included the Enterobacteriaceae, Pseudomonas aeruginosa, Pseudomonas cepacia, Ewingella americana, and Legionella pneumophila. Intrageneric spread of the same or similar R plasmids has nearly always occurred within the Enterobacteriaceae in large medical centers or Veterans Administration hospitals. High-risk nurseries and burn units have been conspicuous foci for R plasmid evolution. Hospital epidemiologists and clinical microbiologists will likely have an ever-increasing need to determine the plasmid content of gram-negative bacilli producing endemic and epidemic nosocomial infections.

Molecular and epidemiological analysis of penicillinase producing strains of Neisseria gonorrhoeae isolated in Canada 1976-84: evolution of new auxotypes and beta lactamase encoding plasmids.

Though the number of penicillinase producing Neisseria gonorrhoeae (PPNG) strains isolated in Canada comprises under 1% of all gonococcal isolates, it continues to increase appreciably each year. Most strains are imported from areas of endemic infection with PPNG strains. Two local outbreaks in 1984, however, were notable for the number of patients infected and for the distinctive phenotypes of the strains. One outbreak was caused by a wild type strain, of serovar BACJK with a new 3.05 megadalton penicillinase encoding plasmid, whereas the other was caused by strains with the Asia+ plasmid type, serovar AE and with a proline and ornithine requiring auxotype. Five plasmid patterns (Africa+, Africa-, Asia+, Asia-, and Toronto+) were observed among the PPNG strains. The association between plasmid content and specific auxotype (such as Asia plasmid with proline requiring auxotype or Africa plasmid with wild type auxotype) and inhibition by phenylalanine continues to be unexplained.

Colonization antigens, antibiotic resistance and plasmid content of enterotoxigenic Escherichia coli isolated from piglets with diarrhoea in galicia (North-Western Spain)

Escherichia coli colonies isolated from 50 diarrhoeic and 29 healthy piglets were investigated for several properties related to pathogenicity, such as production of heat-labile (LT) and heat-stable (STa) enterotoxins, presence of K88 and K99 colonization antigens, mannose-resistant haemagglutinating activity (MRHA), β-haemolysis and antibiotic resistance. The objective was to establish the toxic and adhesive abilities of E. coli strains that cause porcine diarrhoea in Galician farms. Fifty-seven colonies from 14 diarrhoeic piglets formed STa, while no STa + colony was detected from healty piglets. Thirty-four of the 57 STa + colonies were resistant to gentamicin. Sixteen representative STa + strains isolated from the 14 infected piglets were serotyped, investigated for plasmid content and examined by electron microscopy. Of these STa + strains, 15 belonged to serotype 0141:K85ab and carried on their surface the fimbrial antigen P987. The remaining representative STa + strain belonged to serotype 0101:K30 and was K99 +, being the only STa + strain with MRHA activity. All 15 STa + P987 + strains possessed a similar plasmid pattern, with three plasmids ranging in molecular weight from 33 × 10 6 to 74 × 10 6; nine of the gentamicin-resistant strains possessed an additional plasmid of molecular weight 16 × 10 6, which was absent in the six gentamicin-sensitive strains. Strains producing LT or K88 antigen were not detected. Forty-one MRHA + colonies were isolated at similar rates from both diarrhoeic and healthy piglets. Twelve of the 19 non-enterotoxigenic MRHA + strains of which the O-group was established, belonged to serogroups (01, 02, 07, 08, 09 and 075) typical of the human E. coli strains that cause extraintestinal infections. Finally, a statistically significant association between haemolytic and MRHA activities in porcine E. coli was found. In conclusion, it was found that STa + E. coli strains belonging to serotype 0141:K85ab:P987 are associated with porcine diarrhoea in Galicia. Additionally, no correlation between the isolation of non-ETEC MRHA + strains and diarrhoea was observed.

Plasmid profile analysis in epidemiological studies of animal Salmonella typhimurium infection in Japan.

Plasmid profiles were investigated in 65 isolates of Salmonella typhimurium derived from animal outbreaks during the period of 1978 through 1983 in Japan. Incidence of plasmids, drug-resistance, and conjugative R plasmids were extraordinarily high in these isolates. This high incidence reflects the prophylactic and therapeutic use of antibiotics. Most isolates from diseased animals, cohabiting animals, and each farm showed the same or similar plasmid patterns. However, there was a difference in plasmid patterns within strains isolated from each of several animals. It may be that one or two plasmids were introduced or deleted in these strains, leading to the difference discerned in strains isolated from the same animal. It was also shown that during one epidemic, two strains of S. typhimurium were involved that could be distinguished by plasmid profile analysis. Our conclusion is that when S. typhimurium strains isolated from animals reared in limited areas exhibit identical or similar plasmid patterns, they are derived from the same source and that when strains isolated in a limited area exhibit quite a different plasmid pattern, these strains are derived from independent sources.

Characterization of a large plasmid of Rhizobium meliloti involved in enhancing nodulation

The plasmid pattern of Rhizobium meliloti strain GR4 was studied and a gene bank of one of the large plasmids (pRmeGR4) of 140 Mdal, was constructed using the broad host range vector pRK290. A restriction map was established with EcoRI. Two regions of this plasmid involved in the infectivity of GR4 on Medicago sativa were identified. An EcoRI fragment hybridizing with the PstI-nif fragment of pID1 was also identified. However, no homology to the cloned Klebsiella pneumoniae nitrogenase genes (pSA30) was detected.

Plasmid characterization of Shigella spp. isolated from children with shigellosis and asymptomatic excretors.

Strains of Shigella dysenteriae type 1 and Sh. flexneri isolated during 1981-82 from children with shigellosis and also from asymptomatic excretors were examined for drug resistance and for the presence of plasmids. Shigella strains isolated from dysenteric children showed multiple plasmid bands. Thirty-eight percent of the strains transferred the drug resistance factor(s), either partially or fully to a recipient Escherichia coli K12 strain. Plasmids in the molecular weight range from between 44-76 Mdal were correlated with drug resistance. It was found that multi-resistant clinical isolates generally harbour a single large transmissible plasmid. Strains isolated from asymptomatic excretors demonstrated plasmid patterns different from those isolated from children with shigellosis although the bands were relatively homogeneous within each group. Both the groups showed the presence of a 140 Mdal plasmid band conferring invasiveness and such strains gave a positive Sereny test. This study thus shows that Shigella strains from asymptomatic excretors also retain invasiveness.

Mutants of Pseudomonas facilis Defective in Lithoautotrophy

SUMMARY: Mutants of Pseudomonas facilis impaired in lithoautotrophic metabolism (Aut-) were obtained by Tn5 mutagenesis, mitomycin C treatment or incubation at sublethal temperature. A colony assay provided a fast screening method for hydrogenase-negative mutants. Three classes of mutants were identified: the first had lost the ability to grow autotrophically with H2 and heterotrophically with NO3 - as nitrogen source; the second lacked both hydrogenase and ribulose-1,5-bisphosphate carboxylase activity but nitrate metabolism was unaffected; the third retained the activities of the key enzymes of lithoautotrophic metabolism but failed to grow with H2 and CO2. All of the mutants showed the plasmid pattern of the wild-type.

Molecular epidemiology of plasmid patterns in Shigella dysenteriae type I obtained from an outbreak in West Bengal (India)

Multiple antibiotic-resistant Shigella dysenteriae type 1 isolates from a recent epidemic in West Bengal (India) showed identical plasmid patterns. All isolates were resistant to ampicillin (Am), chloramphenicol (Cm), tetracycline (Tc), streptomycin (Sm) and trimethoprim (Tp) and contained 6 plasmids, ranging from 2.5–120 kb. The Am resistance determinant was located on the 120 kb plasmid. This plasmid was unstable when the S. dysenteriae strains were grown above 37°C. The Bangladesh strains of S. dysenteriae type 1 showed identical plasmid patterns, except that many isolates were Am-sensitive and lacked the 120 kb plasmid. In strains from both Bangladesh and West Bengal, predominantly group-B plasmids conferred resistance to Cm and Tc. Comparisons of EcoR1 fragments generated from the total plasmid DNA content of each strain support the view that the plasmids present in the S. dysenteriae type 1 strains isolated from all recent epidemics in India and Bangladesh were identical.

A self-transmissible plasmid of an enteropathogenicEscherichia colistrain codes for mannose-resistant haemagglutinin and for antibiotic resistance

Four enteropathogenic Escherichia coli strains were studied with respect to their antibiotic resistance characters, plasmid patterns, toxin production and haemagglutination properties. Two of these strains showed multiple antibiotic resistance characters, although all possessed several plasmids of varying sizes. One of the strains DD-41 showed the presence of a non-fimbrial cell-associated mannose-resistant haemagglutinin (MRHA) which was encoded by a 70 MDa plasmid. Conjugation experiments demonstrated that this MRHA-containing plasmid also coded for ampicillin and tetracycline resistance factors and was self-transmissible.

Molecular epidemiology of plasmid patterns inShigella dysenteriaetype I obtained from an outbreak in West Bengal (India)

Multiple antibiotic-resistant Shigella dysenteriae type 1 isolates from a recent epidemic in West Bengal (India) showed identical plasmid patterns. All isolates were resistant to ampicillin (Am), chloramphenicol (Cm), tetracycline (Tc), streptomycin (Sm) and trimethoprim (Tp) and contained 6 plasmids, ranging from 2.5–120 kb. The Am resistance determinant was located on the 120 kb plasmid. This plasmid was unstable when the S. dysenteriae strains were grown above 37°C. The Bangladesh strains of S. dysenteriae type 1 showed identical plasmid patterns, except that many isolates were Am-sensitive and lacked the 120 kb plasmid. In strains from both Bangladesh and West Bengal, predominantly group-B plasmids conferred resistance to Cm and Tc. Comparisons of EcoR1 fragments generated from the total plasmid DNA content of each strain support the view that the plasmids present in the S. dysenteriae type 1 strains isolated from all recent epidemics in India and Bangladesh were identical.

Relationship between auxotype, plasmid pattern and sensitivity to antibiotics in penicillinase-producingNeisseria gonorrhoeae

Relationship between auxotype, plasmid pattern and sensitivity to antibiotics in penicillinase-producingNeisseria gonorrhoeae

Epidemiological markers of Shigella sonnei infections: R-plasmid fingerprinting, phage-typing and biotyping

In 1980, the number of Shigella sonnei strains isolated in Sicily increased markedly. Approximately 80% of the isolates belonged to phage-type 3 and showed the same antibiotic resistance pattern, suggesting that an epidemic had been going on for several months. Plasmid analysis of strains isolated at various times in different places supported this view. Agarose gel electrophoresis of plasmid preparations from seven selected phage-type 3 isolates showed the presence of two plasmids, of 80 megadaltons (Mdal) and 55 Mdal, respectively. In addition, all but one harboured a 2.8-Mdal plasmid, while a 30-Mdal and a 47-Mdal plasmid were, respectively, present in two other isolates. The 80-Mdal plasmid was self-transmissible to Escherichia coli K12, which acquired "en bloc" the resistance patterns of the donor strains. All the self-transmissible R plasmids fell into the incompatibility group I1 and showed a similar endonuclease cleavage pattern. An S. sonnei strain which was isolated during the same period, but did not belong to phage-type 3, exhibited a totally different plasmid pattern. We can conclude that phage-typing and R-plasmid characterization (i.e. incompatibility group, molecular weight and endonuclease cleavage pattern) represent the most reliable methods for epidemiologic study of S. sonnei isolates.

Survey of plasmids inClostridium butyricum andClostridium beijerinckii strains from different origins and different phenotypes

A total of 50Clostridium butyricum strains from clinical and nonclinical sources and 14C. beijerinckii strains originating from dairy products were analyzed for their plasmid content, antibiotic resistance, and bacteriocinogenic activity. The incidence of antibiotic resistance and presence of plasmidic DNA was more widespred among theC. butyricum strains from clinical source than among theC. beijerinckii strains, all of the originating from dairy products. In many of theC. butyricum strains, a small plasmid of 4.5 megadaltons was encountered. No relation was found between the plasmid pattern, the antibiotic resistance, the geographic localization of the isolates, or the clinical condition of the patients.