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Biomedical subjects

E E Udo

Publications and source records attributed to E E Udo.

At least 37 records · Page 2Linked to original sources
PubMed1998

Conjugative transfer of high-level mupirocin resistance and the mobilization of non-conjugative plasmids in Staphylococcus aureus.

A 31-kb conjugative plasmid, pXU12, encoding high-level mupirocin resistance via the mupA gene, was isolated from a multiply resistant Staphylococcus aureus isolate, MB494. pXU12 was derived by a deletion of an 8.6-kb EcoRI fragment from a approximately 40-kb plasmid in the parental isolate during curing and conjugation experiments. It transferred rapidly in conjugation experiments, with transconjugants being obtained after 15 min of mating, and mobilized a 3.0-kb erythromycin resistance plasmid, pXU13, from the parental isolate at high frequencies. The cotransfer of pXU13 by pXU12 was unaffected by varying the donor-recipient ratios in the mating mixtures or the length of incubation. pXU12 also mobilized 11 other nonconjugative plasmids belonging to different incompatibility groups and cotransferred at high frequencies. The ability of pXU12 to mobilize different nonconjugative plasmids suggested that it can be used to transfer and isolate non-conjugative plasmids from resistant S. aureus strains in the laboratory, especially from strains where phage-dependent methods of transfer are not applicable.

Conjugation, Genetic↗
PubMed1997

Conjugative transfer of high-level mupirocin resistance from Staphylococcus haemolyticus to other staphylococci.

A conjugative plasmid, pXU10, encoding high-level mupirocin resistance was transferred from a Staphylococcus haemolyticus isolate, CN216, to other coagulase-negative staphylococci and a restriction deficient Staphylococcus aureus strain, XU21, but not to clinical isolates or a restriction-proficient laboratory strain (strain WBG541) of S. aureus. However, from XU21 it was cotransferred with a 3.5-kb chloramphenicol resistance plasmid to WBG541. The results demonstrated the ability of pXU10 to mobilize nonconjugative plasmids.

Anti-Bacterial Agents↗
PubMed1996

Molecular and phage typing of Staphylococcus aureus harbouring cryptic conjugative plasmids.

The spread of antibiotic resistant-bacterial pathogens in a hospital could be due to the spread of a resistant strain or the spread of a resistance plasmid among unrelated strains. In this study the relatedness of Staphylococcus aureus isolates carrying identical cryptic conjugative plasmids was determined by a combination of resistance profiles, plasmid patterns, pulsed field gel electrophoresis of SmaI digested chromosomal DNA and phage typing. Results of the different typing techniques were in agreement to one another and demonstrated that the isolates were of three different types. The results suggested that a cryptic conjugative plasmid had spread to different S. aureus isolates in the hospital. This is an example of plasmid spread as opposed to strain spread.

Bacterial Typing Techniques↗
PubMed1996

A phage-mediated transfer of chromosomally integrated tetracycline resistance plasmid in Staphylococcus aureus.

The ability of a Staphylococcus aureus isolate WBG7416 to transfer its resistance determinants was studied in conjugation and mixed-culture transfer experiments. It carried plasmid-borne resistance to kanamycin, trimethoprim, chloramphenicol, cadmium, propamidine isethionate, and chromosomal resistance to methicillin, gentamicin, streptomycin, erythromycin, clindamycin, tetracycline, and minocycline. It transferred tetracycline resistance in mixed-culture transfer but not in conjugation experiments. DNA-DNA hybridization of genomic DNA from the tetracycline-resistant transferrants against a labeled tetracycline resistance plasmid, pWBG3, probe revealed the presence of an integrated plasmid in their chromosomes. In contrast, no homology to the probe was detected in the chromosome of a tetracycline-resistant mutant of the recipient strain. The results established a role for a bacteriophage in the transfer of chromosomal tetracycline resistance in WBG7416 besides demonstrating the presence of an integrated tetracycline resistance plasmid in the transferrants. It also offered an insight into the nature of the integrated plasmid.

Conjugation, Genetic↗
PubMed1996

Nasal carriage of enterotoxin-producing Staphylococcus aureus among restaurant workers in Kuwait City.

Enterotoxin-producing Staphylococcus aureus is a common cause of staphylococcal food poisoning. To determine the incidence of carriage of enterotoxin-producing S. aureus in a sample of the healthy population in Kuwait city, restaurant workers in the city were screened for nasal carriage of S. aureus. 26.6% of 500 workers studied carried S. aureus and 86.6% of the S. aureus produced staphylococcal enterotoxins. 28% produced enterotoxin A, 28.5% produced enterotoxin B, 16.4% produced enterotoxin C and 3.5% produced enterotoxin D. Ten isolates produced both enterotoxins A and B or A and C. 73% of the isolates were untypeable with standard phages. However, 17.1%, 3% and 6% belonged to phage groups I, II and III respectively. The results demonstrated a high level of enterotoxigenic S. aureus carriage among restaurant workers which although lower than that reported for the general population and hospital workers may be important in the restaurant industry.

Bacteriophage Typing↗
PubMed1996

Incidence of microbial growth from the tip of the embryo transfer catheter after embryo transfer in relation to clinical pregnancy rate following in-vitro fertilization and embryo transfer.

A total of 110 consecutive women was studied prospectively at the time of transcervical embryo transfer following conventional in-vitro fertilization and intracytoplasmic sperm injection procedures. Microbiological cultures were performed on endocervical swabs and embryo transfer catheter tips. Positive microbial growths were observed from endocervical swabs in 78 (70.9%) women and from catheter tips in 54 (49.1%) women. The clinical pregnancy rates were 57.1% in the group of patients without growth and 29.6% in the group with positive microbial growth from catheter tips. As microbial contamination at embryo transfer may influence implantation rates, prospective studies are justified to determine whether eradication of endocervical micro-organisms is possible and whether their eradication will improve implantation rates.

Adult↗
PubMed1996

Molecular characterization of epidemic ciprofloxacin- and methicillin-resistant Staphylococcus aureus strains colonizing patients in an intensive care unit.

Eighteen methicillin-resistant Staphylococcus aureus (MRSA) samples isolated from patients and the environment in an intensive care unit (ICU) during a routine surveillance were tested for antimicrobial resistance and typed by pulsed-field gel electrophoresis. Three pulsed-field patterns were observed. Sixteen were ciprofloxacin resistant and had identical pulsed-field patterns. The results suggested that a ciprofloxacin-resistant MRSA clone had contaminated the environment and spread among patients. This study demonstrates the application of infection control surveillance combined with strain typing in detecting MRSA colonization in the ICU where it was not known to exist.

Anti-Infective Agents↗
PubMed1995

Transfer of plasmid-borne resistance from a multiply-resistant Staphylococcus aureus isolate, WBG1022.

Staphylococcus aureus isolate, WBG1022, was resistant to penicillin, kanamycin, neomycin, streptomycin, chloramphenicol, trimethoprim, cadmium, and ethidium bromide and harbored plasmids of 34.5, 24.5, 4.4, 3.2, and 2.6 kilobases. The plasmids were transferred in mixed-culture transfer and conjugation experiments. No resistance phenotype was associated with the 2.6-kb plasmid. The 3.2-kb and 4.4-kb plasmids encoded chloramphenicol and streptomycin resistance respectively. The 24.5-kb plasmid, pWBG626, encoded joint resistance to penicillin, kanamycin, neomycin, and ethidium bromide. Resistance to trimethoprim and cadmium were chromosomal. The 34.5-kb plasmid, pWBG661, had no resistance phenotype but was found to be conjugative. It also mobilized the 4.4-kb and 24.5-kb plasmids in WBG1022. Restriction endonuclease analysis of pWBG661 with EcoRI, ClaI, PvuII, and BglII restriction enzymes demonstrated that pWBG661 was identical to two previously isolated S. aureus conjugative plasmids, pWBG620 and pWBG637, that also lack resistance phenotypes.

Conjugation, Genetic↗
PubMed1995

Antimicrobial resistance of coagulase-negative staphylococci from a Kuwait hospital.

This study investigated the incidence of antimicrobial resistance in clinically significant coagulase-negative staphylococci at the Mubarak Al Kabeer Hospital, Kuwait. A total of 104 isolates of coagulase-negative staphylococci consisting of S. epidermidis (67), S. haemolyticus (16), S. saprophyticus (6), S. simulans (2), S. hominis (4), S. albus (2), S. sciuri (3), S. warneri (2), S. capitis (1), and S. xylosus (1) were isolated from clinical specimens over a 6-7 month period and tested for resistance to 22 antibacterial agents and the ability to produce slime. They were all susceptible to vancomycin and mupirocin but intermediate resistance to teicoplanin was detected in seven isolates: 83 and 47.7% were resistant to penicillin G and methicillin, respectively, 57% were resistant to gentamicin, 49.5% to erythromycin, 50.4% to tetracycline, and 52.3% to trimethoprim. Resistance to heavy metals and the nucleic-acid binding compound was also detected. More than half of S. epidermidis, S. saprophyticus, S. simulans, S. hominis, and all of S. haemolyticus were multiply resistant to three or more groups of antibiotics and there was a significant association between slime production and resistance to multiple antimicrobial agents in S. epidermidis. The results revealed a high level of resistance to commonly used agents.

Anti-Bacterial Agents↗
PubMed1994

Emergence of high-level mupirocin resistance in methicillin-resistant Staphylococcus aureus in Western Australia.

Six mupirocin-resistant Staphylococcus aureus were isolated from patients living in the northern part of Western Australia (WA). They were all resistant to methicillin, tetracycline, trimethoprim and cadmium and harboured similar 41.4 kb plasmids. Transfer and curing experiments with one of the isolates, WBG7569, demonstrated that the 41.4 kb plasmid encoded resistance to mupirocin, tetracycline, trimethoprim and cadmium. The isolates were compared by pulsed-field gel electrophoresis with methicillin-resistant S. aureus (MRSA) previously isolated from the Kimberley region in the northern-most part of WA (WA MRSA). The mupirocin-resistant isolates were found to be closely related to WA MRSA suggesting that they were WA MRSA which had acquired a new multiple-resistance plasmid encoding high-level mupirocin resistance.

Cadmium↗
PubMed1993

Genetic analysis of community isolates of methicillin-resistant Staphylococcus aureus in Western Australia.

Methicillin-resistant Staphylococcus aureus (MRSA) obtained from patients who had not been hospitalized outside Western Australia (WA) were studied for antimicrobial resistance and plasmid content and by pulsed-field gel electrophoresis. They were found to be of several types, none of which appeared to be related to MRSA which have been previously studied. It appears that new MRSA strains have emerged in communities in the far north of WA and are being isolated at an increasing frequency in Perth hospitals 2000 km south.

Bacterial Typing Techniques↗
PubMed1993

Genetic analysis of methicillin-resistant Staphylococcus aureus from a Nigerian hospital.

Methicillin-resistant strains of Staphylococcus aureus isolated during 1985 and 1987 at a Nigerian hospital were compared by resistance profiles, plasmid analysis, and pulsed-field gel electrophoresis of chromosomal DNA. The results indicated that the isolates from the two periods were unrelated with regard to all three aspects. None of the isolates was similar to the classical MRSA nor to the epidemic MRSA of Australia or the UK. The MRSA isolated in 1985 had a similar plasmid to MRSA isolates from Singapore, but differed from them when compared by pulsed-field gel electrophoresis.

Conjugation, Genetic↗
PubMed1992

Typing of methicillin-resistant Staphylococcus aureus with IS256.

A simple one-step procedure is described for specifically amplifying and labelling insertion element IS256 which is associated with the gentamicin-resistance transposon Tn4001. The product has been used to probe DNA digests of methicillin-resistant Staphylococcus aureus. The resulting restriction fragment length polymorphisms were found to be able to distinguish isolates which were indistinguishable by other typing methods. The probe also hybridised with methicillin-resistant Staphylococcus aureus which were isolated before the emergence of gentamicin resistance, demonstrating its usefulness in typing species other than those that are gentamicin-resistant.

Bacterial Typing Techniques↗
PubMed1992

Conjugative trimethoprim resistance in Staphylococcus aureus.

A multiply resistant Staphylococcus aureus isolate, WBG7410, harbours plasmids of 38, 26, 2.8, 2.4 and 1.9 kb and transfers trimethoprim and kanamycin resistance at high frequencies by conjugation. The transconjugants contained the 38-kb plasmid, pWBG707, and the 2.8-kb plasmid. Plasmid pWBG707 was shown to encode trimethoprim resistance, was conjugative and mobilised at high frequencies the 2.8-kb plasmid which presumably encodes kanamycin resistance. Plasmid pWBG707 was isolated mostly in the open circular form and analysis with EcoRI restriction endonuclease suggests that pWBG707 is a new conjugative plasmid distinct from the other conjugative plasmids reported in S. aureus.

Conjugation, Genetic↗
PubMed1992

Intra- and inter-species mobilisation of non-conjugative plasmids in staphylococci.

The ability of Staphylococcus aureus conjugative plasmids to mobilise non-conjugative resistance plasmids from clinical isolates of S. aureus and S. epidermidis was studied. Plasmids which could not be transferred by transduction or mixed-culture transfer were transferred from phage-typable and non-typable S. aureus and from S. epidermidis. Plasmids encoding single resistance determinants were transferred by mobilisation whereas multiple-resistance plasmids were transferred as co-integrates between the conjugative and non-conjugative plasmids. This study demonstrates that mobilisation is a useful tool for the transfer and study of staphylococcal plasmids and illustrates how antibiotic resistance could be transferred between staphylococci in vivo.

Anti-Bacterial Agents↗
PubMed1991

A new incompatibility group plasmid in Staphylococcus aureus.

The conjugative plasmid pWBG637 and its derivatives, pWBG636 and pWBG642, were tested for incompatibility against conjugative and non-conjugative plasmids in Staphylococcus aureus. They were compatible with other conjugative plasmids and plasmids of the 14 established incompatibility groups. They therefore define a new Incompatibility group 15.

Conjugation, Genetic↗
PubMed1991

Transfer of resistance determinants from a multi-resistant Staphylococcus aureus isolate.

The clinical isolate Staphylococcus aureus WBG1024 was resistant to cadmium, benzyl penicillin, kanamycin, neomycin, streptomycin, tetracycline and trimethoprim and harboured a conjugative plasmid pWBG637 (34.5 kb) and non-conjugative plasmids of 23.8, 4.4, 2.8 and 1.9 kb. Transduction and mixed-culture transfer experiments demonstrated that the 4.4-kb plasmid (pWBG632) encoded resistance to tetracycline and the 23.8-kb plasmid (pWBG628) encoded resistance to cadmium, benzyl penicillin, kanamycin, neomycin and streptomycin. The conjugative plasmid pWBG637 was able to mobilise a further 4.4-kb plasmid (pWBG633) encoding streptomycin resistance and recombined with the multiresistance plasmid pWBG628 to produce transconjugantes of various resistance phenotypes.

Blotting, Southern↗