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Journal ArticleDOI

Occurrence of quinolone resistance in Staphylococcus aureus from nosocomial infection.

01 Dec 1992-Epidemiology and Infection (Cambridge University Press)-Vol. 109, Iss: 3, pp 413-421

TL;DR: The phenotypic association of quinolone resistance and MRSA is rather likely due to a higher frequency of spontaneous resistant mutants which are present in natural populations of MRSA.

AbstractAmong 63 Staphylococcus aureus isolates (one isolate per one patient) counted from infections (from August to November 1991) in hospital T., eight exhibited resistance to fluoroquinolones. Seven of these quinolone-resistant isolates were multiply- and methicillin-resistant S. aureus (QR-MRSA). The results of phage-, plasmid- and genotyping (pulsed field electrophoresis) revealed that six different strain-clones of these MRSA were spread in the hospital. In vitro spontaneous mutants resistant to fluoroquinolones are 10-100-fold more frequent in MRSA than in other S. aureus when selected on isosensitest-agar containing 1 microgram/ml of ciprofloxacin. However, the same mutant frequencies were found in strain 8325-4 with and without the mecA-determinant. The resistance phenotype was stable over 30 generations of subculture in nutrient broth as well in natural quinolone resistant MRSA as in mutants of other types of S. aureus selected in vitro. The phenotypic association of quinolone resistance and MRSA is rather likely due to a higher frequency of spontaneous resistant mutants which are present in natural populations of MRSA. Data of chemotherapy prior to the isolation of S. aureus show that three of seven patients from whom QR-MRSA were isolated were treated with a quinolone. In eight cases of infections with non-MRSA and quinolone treatment the isolated S. aureus strains were in vitro sensitive to quinolones.

Topics: Staphylococcus aureus (56%), Drug resistance (52%), Quinolone (52%), Ciprofloxacin (51%), Antibiotics (51%)

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Citations
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Journal ArticleDOI
Abstract: Summary Resistance to fluoroquinolones among Gram-positive cocci has emerged as these antimicrobial agents have become extensively used in clinical medicine. Resistance is effected by changes in the bacterial target enzymes DNA gyrase and topoisomerase IV, which reduce drug binding, and by action of native bacterial membrane pumps that remove drug from the cell. In both cases, quinolone exposure selects for spontaneous mutants that are present in large bacterial populations, and which contain chromosomal mutations that alter the target protein or increase the level of pump expression. Resistance among clinical isolates has been greatest in Staphylococcus aureus and particularly among meticillinresistant strains, in which both selection by quinolone exposure and transmission of clonal strains in health-care settings have contributed to high prevalence. Resistance in Streptococcus pneumoniae has also emerged in the community. Fluoroquinolone resistance has arisen in multidrug-resistant clones and its prevalence has been especially high in Hong Kong and Spain. Further spread and selection of such resistance could compromise the utility of a valuable class of antimicrobial agents, a point that emphasises the importance of the careful use of these agents in appropriate patients and doses, as well as careful infection-control practices.

285 citations


Journal ArticleDOI
TL;DR: It is difficult to assess whether the percentage of NIs due to cross-transmission determined for this ICU may be the crucial explanation for the relatively high infection rate in comparison to other surgical ICUs.
Abstract: OBJECTIVE: To determine the percentage of cross-transmissions in an intensive care unit (ICU) with high nosocomial infection (NI) rates according to the data of the German Nosocomial Infection Surveillance System. SETTING: A 14-bed surgical ICU of a 1,300-bed, tertiary-care teaching hospital. METHOD: Prospective surveillance of NIs during a period of 9 months. If an NI was present, the isolates of the following indicator pathogens were stored and typed by species: Staphylococcus aureus, Enterococcus species, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacter species. Pulsed-field gel electrophoresis was performed for typing of S. aureus strains and arbitrarily primed polymerase chain reaction was applied for the other pathogens. The presence of two indistinguishable strains in two patients was considered as one episode of cross-transmission. RESULTS: Two hundred sixty-two patients were observed during a period of 2,444 patient-days; 96 NIs were identified in 59 patients and the overall incidence density of NI was 39.3 per 1,000 patient-days. For 104 isolates, it was possible to consider typing results. Altogether, 36 cross-transmissions have lead to NIs in other patients. That means at least 37.5% of all NIs identified were due to cross-transmissions. CONCLUSION: Because of the method of this study, the percentage of NIs due to cross-transmission identified for this ICU is an at least number. In reality, the number of cross-transmissions, and thus the number of avoidable infections, may have been even higher. However, it is difficult to assess whether the percentage of NIs due to cross-transmission determined for this ICU may be the crucial explanation for the relatively high infection rate in comparison to other surgical ICUs.

113 citations


Journal ArticleDOI
TL;DR: Isolates with heterogenous and homogeneous phenotypes, fell into clearly distinct clusters and thus formed two clonally related MRSA strains, and differences were seen with phage and biochemical typing, and antimicrobial resistance patterns.
Abstract: The DNA fragments of 28 distinct isolates of methicillinresistant Staphylococcus aureus (MRSA) originating from different hospitals in Warsaw and Lodz, were studied. They were obtained by cleavage with restriction endonuclease Sma I and subsequently analysed by pulsed-field electrophoresis. Sixteen different patterns were seen and clusters of related strains were clearly distinguishable. Minor differences in fragment patterns within these clusters and among epidemiologically related strains, revealed genomic rearrangements in the course of clonal dissemination of particular strains. The isolates were also checked for the expression of methicillin resistance. Isolates with heterogenous and homogenous phenotypes, fell into clearly distinct clusters and thus formed two clonally related MRSA strains. Differences were also seen with phage and biochemical typing, and antimicrobial resistance patterns.

37 citations


Journal ArticleDOI
TL;DR: Six commercially available agglutination tests for the detection of meticillin-sensitive S. aureus (MSSA) and mecA-positive MRSA strains were evaluated and only the Dry Spot Staphytect Plus test correctly identified all 52 MRSAusters.
Abstract: Most routine laboratory detection of Staphylococcus aureus isolates is based on rapid agglutination test systems. Failure of agglutination assays to identify meticillin-resistant S. aureus strains (MRSA) has been demonstrated. The aim of this study was to evaluate six commercially available agglutination tests for the detection of meticillin-sensitive S. aureus (MSSA) and mecA-positive MRSA strains. The Dry Spot Staphytect Plus test (Oxoid), the Pastorex Staph Plus test (Bio-Rad), the Slidex Staph-Kit and Slidex Staph Plus test (bioMerieux), the Staphaurex Plus test (Remel) and the Staphylase Test (Oxoid) were used. As determined by pulsed field gel electrophoresis, 52 distinct MRSA strains from five countries, 83 MSSA strains and 150 coagulase-negative staphylococci were included. Species identification and determination of susceptibility patterns were performed using colony morphology, Gram stain, catalase testing, tube coagulase testing, DNase testing, mannitol fermentation, susceptibility testing towards oxacillin by Etest, coagulase gene PCR, fibrinogen receptor gene PCR and PCR of the mecA gene. Sensitivity of the agglutination tests ranged from 82.7 to 100.0 % for MRSA strains and 92.8 to 100.0 % for MSSA strains, respectively. Specificity of the test systems ranged from 91.3 to 99.1 %. None of the six agglutination assays produced correct reactions for all staphylococci tested. Only the Dry Spot Staphytect Plus test correctly identified all 52 MRSA strains. For the other tests kits, sensitivity of MRSA detection was lower than for MSSA isolates. Depending upon the local MRSA prevalence and the parameter of interest (sensitivity or specificity), these test systems may be useful for routine diagnostic purposes.

32 citations


Cites methods from "Occurrence of quinolone resistance ..."

  • ...Contourclamped homogeneous electric field electrophoresis was performed as described (Witte & Grimm, 1992) based on a previously published method (Chu et al., 1986)....

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Journal ArticleDOI
TL;DR: Clonal dissemination of two different MRSA strains, both clumping factor negative, has been observed in Germany for more than a year and each exhibits a characteristic genomic DNA fragment pattern.
Abstract: SUMMARY Clonal dissemination of two different MRSA strains, both clumping factor negative, has been observed in Germany for more than a year. Both strains possess the mec-A determinant and each exhibits a characteristic genomic DNA fragment pattern. One strain has spread in the north, the other in the south-west of Germany. Intensive care units are mainly affected by MRSA-infections and probably play a special role in further intra- and inter-hospital spread.

30 citations


References
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Journal Article
TL;DR: A detailed account of methods that have been found satisfactory for propagating the phages are given and a standard testing routine by which the stability of the phage preparations can be verified is defined.
Abstract: Standardized methods are essential if phage typing of staphylococci is to be reliable and if the results obtained in different laboratories are to be compared. This paper, prepared on behalf of the Subcommittee on Phage Typing of Staphylococcus of the Nomenclature Committee of the International Association of Microbiological Societies, gives a detailed account of methods that have been found satisfactory for propagating the phages and defines a standard testing routine by which the stability of the phage preparations can be verified. Technical details are given of methods recommended for determining the phage type of staphylococci and the interpretation of differences between the types is discussed. The need for close collaboration between the epidemiologist and the laboratory worker in the use of phage typing is emphasized.

817 citations


"Occurrence of quinolone resistance ..." refers methods in this paper

  • ...Phage typing was performed using the international basic set [11] and two sets of experimental phages (for details see [12]....

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Journal ArticleDOI
TL;DR: A high-molecular-weight PBP (PBP-2a; approximate size, 78,000 daltons) was detected that was only present in the resistant bacteria but not in the isogenic sensitive strain, and in cultures grown at pH 5.2, the extra PBP was not detectable.
Abstract: Methicillin resistance in Staphylococcus aureus has been associated with alterations in the penicillin-binding proteins (PBPs). An intriguing property of all methicillin-resistant staphylococci is the dependence of resistance on the pH value of the growth medium. Growth of such bacteria at pH 5.2 completely suppressed the expression of methicillin resistance. We have examined the PBP patterns of methicillin-resistant staphylococci grown at pH 7.0. We detected a high-molecular-weight PBP (PBP-2a; approximate size, 78,000 daltons) that was only present in the resistant bacteria but not in the isogenic sensitive strain. In cultures grown at pH 5.2, the extra PBP was not detectable. Images

808 citations


Journal ArticleDOI
TL;DR: The status of these agents as revealed in the published English literature is reviewed in a two-part minireview, considering the structures, mechanisms of action and resistance, and spectra of activity of the six aforementioned fluoroquinolones with reference to nalidixic and oxolonic acids.
Abstract: INTRODUCTION During the past 5 to 7 years, much attention has been given to the synthesis of new 4-quinolone-3-carboxylates and to the evaluation of these newly prepared agents for antibacterial activity, a revival of interest generated by the discovery of nalidixic and oxolinic acids mtny years ago. This renewed effort uncovered a. number of 6-fluoro-7piperazino-4-quinolones noteworthy for both the breadth and intensity of their activities against gram-negative bacilli and cocci in vitro and for the capacity to control experimentally induced systemic infections with selected bacteria when administered orally in well-tolerated doses (21). The most active representatives of this compound class, designated fluoroquinolones, include norfloxacin (AM-715, MK-0366), ofloxacin (DL-8280), ciprofloxacin (Bay o 9867), amifloxacin (WIN 49375), enoxacin (AT-2266, CI-919), and pefloxacin (1589-RB). The prim4ary target of nalidixic acid and probably also all the fluoroquinolones is DNA gyrase, an essential bacterial enzyme that maintains superhelical twists in DNA (13, 18, 24). The promise of the fluoroquinoloies led to their prompt evaluation for pharmacokinetics in human volunteers and cautious assessments of therapeutic potential, including tolerability in selected patients. The encouraging results of these early trials, with the burgeoning interest in further studies, have made it desirable to review the status of these agents as revealed in the published English literature. We have attempted this task in a two-part minireview. The first part here considers the structures, mechanisms of action and resistance, and spectra of activity of the six aforementioned fluoroquinolones with reference to nalidixic and oxolonic acids for comparison. The second part will consider pharmacology, clinical activity, and toxicities in humans (D. C. Hooper and J. S. Wolfson, Antimicrob. Agents Chemother., in press). Other quinolones, such as cinoxacin, pipemidic acid, rosoxacin, and flumequine, will not be discussed directly. Several reviews of cinoxacin have recently appeared (28, 63).

697 citations


"Occurrence of quinolone resistance ..." refers background in this paper

  • ...staphylococci [1] with no difference between methicillinresistant Staphylococcus aureus (MRSA) and methicillin-sensitive strains....

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Journal ArticleDOI

304 citations


"Occurrence of quinolone resistance ..." refers background in this paper

  • ...aureus and Pseudomonas aeruginosa together with therapeutic use correspond to these observations [7, 8]....

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Book
30 Nov 1990
TL;DR: Introduction genome organization and evolution gene transfer and transposons plasmids exoproteins and pathogenicity factors resistance and its spread resistance and epidemiology.
Abstract: Introduction genome organization and evolution gene transfer and transposons plasmids exoproteins and pathogenicity factors resistance and its spread resistance and epidemiology.

272 citations