Christine Braulke

spa Typing of Staphylococcus aureus as a frontline tool in epidemiological typing.

ABSTRACT We determined the value of spa typing in combination with BURP (based upon repeat pattern) grouping analysis as a frontline tool in the epidemiological typing of Staphylococcus aureus, based on a random collection of 1,459 clinical isolates sent to the German Reference Centre for Staphylococci within a 6-month period. The application was found to be helpful for the classification of isolates into the particular clonal lineages currently prevalent in Germany. Due to its major advantages because of the ease of interpretation and the exchangeability of the results, the use of spa typing greatly simplifies communication between laboratories on both the national and the international levels. Thus, it is an excellent tool for national and international surveillance of S. aureus as well as for analysis of the short-term local epidemiology. However, to overcome the limitations of the BURP grouping method in terms of typing accuracy and discriminatory power, the results of the default BURP grouping method must be interpreted with caution. Additional markers, like staphylococcal chromosomal cassette mec, lineage-specific genes, or alternative DNA polymorphisms, are indispensable. They should be selected by dependence on the clonal lineage indicated by spa typing and subsequent BURP analysis as well as on the basis of the particular question to be addressed.

Emergence of methicillin-resistant Staphylococcus aureus with Panton-Valentine leukocidin genes in central Europe.

The aim of the present study was to investigate strains of methicillin-resistant Staphylococcus aureus (MRSA) for the presence of the lukS–lukF determinant of Panton–Valentine leukocidin and to further characterize strains found to contain the genes. During the past 2 years, MRSA containing the lukS–lukF genes for Panton–Valentine leukocidin, particularly those emerging outside of hospitals, have become of interest. MRSA strains sent to the national reference center in Germany were investigated for lukS–lukF by polymerase chain reaction (PCR). If the presence of lukS–lukF was demonstrated, strains were further characterized by molecular typing (determination of SmaI pattern, spa sequence, and multilocus sequence type), PCR demonstration of resistance genes, and characterization of the SCCmec element. Since the end of 2002, MRSA containing Panton–Valentine leukocidin genes have been demonstrated as the causative agent of 28 cases of infection (9 community-acquired cases, 19 sporadic nosocomial cases) in different areas of Germany. Twenty-seven of these 28 isolates exhibited a unique pattern of genomic typing: all exhibited multilocus sequence type 80, spa sequence type 44, and a SmaI macrorestriction pattern that corresponds to a community-acquired strain of MRSA from France and Switzerland. In addition to resistance to oxacillin, the strains exhibited resistance to ciprofloxacin, tetracycline (tetM), and fusidic acid, the last of which is encoded by the far-1 gene. The far-1 gene was shown to be located on the plasmid. One isolate corresponded to community MRSA (cMRSA) of multilocus sequence type 1 from the USA.

Changing pattern of antibiotic resistance in methicillin-resistant Staphylococcus aureus from German hospitals.

OBJECTIVE To investigate the background of changes of resistance phenotypes in methicillin-resistant Staphylococcus aureus (MRSA) from nosocomial infections in German hospitals by molecular typing and identification of particular resistance genes. METHODS Isolates from the network for monitoring the spread of MRSA in Germany were subjected to quantitative susceptibility testing, to molecular typing, and to polymerase chain reaction identification of resistance genes. PARTICIPANTS The network consists of 175 German clinical microbiological laboratories collaborating with the German Reference Center for Staphylococci, which performs typing of staphylococcal isolates from nosocomial infections and data analysis. RESULTS During the past 5 years, MRSA susceptible to other antibiotics such as oxytetracycline, erythromycin, and gentamicin became more frequent. The proportion of epidemic MRSA clones that had been disseminated in the past and that exhibited broad resistance phenotypes decreased, whereas the proportion of recently emerging MRSA carrying only a few other resistance determinants has increased (1994, 11.5%; 1998, 39%). CONCLUSIONS The changing pattern of resistance phenotypes of MRSA from nosocomial infections in Germany is mainly due to the spread of recently emerging epidemic strains that are less frequently resistant to antibacterials other than oxacillin. The observed changes cannot simply be attributed to overall antibiotic consumption.

Clonal dissemination of two MRSA strains in Germany

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.

Analysis of nosocomial outbreaks with multiply and methicillin-resistantStaphylococcus aureus (MRSA) in Germany: Implications for hospital hygiene

SummaryTwo outbreaks of nosocomial infections with MRSA, one in a urological unit in connection with transurethral prostatectomy and the other in an orthopaedic clinic with infections after implantation of prosthetic hips, have been analyzed on the basis of typing MRSA by phagepatterns, plasmid profiles and genomic DNA fragment patterns. Main reasons for these outbreaks were obviously mistakes in hospital hygiene and an inappropriate antibiotic prophylaxis (in the first outbreak a quinolone over about 7 days, in the second a third generation cephalosporin). Both outbreaks could be stopped by measures of hospital hygiene including isolated or cohort nursing of affected patients, and change in antibiotic prophylaxis. Intensive care units (ICUs) are more often affected by MRSA than other clinical settings. As described by the example of an outbreak with MRSA in a municipal hospital, ICUs can play a special role in intrahospital spread of MRSA. The recently observed inter-regional clonal interhospital dissemination of MRSA in Germany is mainly due to a transfer of patients between hospitals; prewarning of the hospital of destination and a number of hygiene measures can prevent further spread.ZusammenfassungZwei Ausbrüche von Krankenhausinfektionen mit MRSA, im ersten Fall in einer urologischen Abteilung im Zusammenhang mit transurethraler Prostatectomy, im zweiten Fall in einer orthopädischen Klinik nach Hüftgelenkersatz, wurden auf der Grundlage der Typisierung von MRSA mittels Lysotypie, Plasmidprofilen und Fragmentmustern der genomischen DNS analysiert. Hauptursachen für diese Ausbrüche waren offensichtliche Fehler der Krankenhaushygiene und unpassende Antibiotikaprophylaxe (beim ersten Ausbruch ein Chinolon über 7 Tage, beim zweiten Ausbruch ein Drittgenerations-Cephalosporin). Beide Ausbrüche konnten durch Maßnahmen der Krankenhaushygiene, die eine Isoliertpflege der betroffenen Patienten einschlossen, und durch Änderungen der Antibiotikaprophylaxe beendet werden. Intensivpflegestationen (ICU) werden deutlich häufiger durch Infektionen mit MRSA betroffen als andere klinische Bereiche. Wie am Beispiel eines Ausbruchs mit MRSA in einem städtischen Krankenhaus beschrieben wird, können ICU eine besondere Bedeutung für die weitere Ausbreitung von MRSA in einem Krankenhaus haben. Die gegenwärtig in Deutschland beobachtete überregionale klonale Ausbreitung von MRSA ist vorrangig auf die Verlegung von Patienten zwischen Krankenhäusern zurückzuführen. Eine Vorwarnung in Verbindung mit rechtzeitig getroffenen Hygienemaßnahmen kann die weitere Ausbreitung verhindern.

Methicillin-resistant Staphylococcus aureus exhibiting genomic fingerprints of phage group I strains in a hospital and in a nurse's family.

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Ergebnisse der Tätigkeit des Nationalen Referenzzentrums für Staphylokokken im Jahr 1998

ZusammenfassungDieser Bericht bezieht sich auf das Auftreten und die Ausbreitung von S. aureus-Stämmen mit besonderer klinischer und epidemiologischer Bedeutung. Die Ergebnisse der Typisierung von MRSA unterschiedlicher klinischer Herkünfte in Deutschland weisen auf eine kontinuierliche Ausbreitung bestimmter Epidemiestämme zwischen Krankenhäusern hin. Daneben wird der Transfer des mecA-Gens in Stämme beoachtet, die zu bisher diesbezüglich empfindlichen klonalen Gruppen von S. aureus gehören. Diese neu entstandenen MRSA sind noch empfindlich gegen eine Reihe von Antibiotika; dies führt zu weniger „breiten” Resistenzphänotypen. Weiterhin erwähnenswert im Hinblick auf die Diagnostik toxinvermittelter S. aureus-Infektionen sind die klinischen Fälle des Toxic-Schock-Syndroms verursacht durch S. aureussecC, nicht aber tst.SummaryThis report focusses on the emergence and spread of S. aureus with special clinical and epidemiological significance. Results from typing MRSA originating from different clinical sources in all Germany reveal that there is a continuing interhospital dissemination of definite epidemic strains and also a spread of the mecA gene to clonal groups of S. aureus which have been until now sensitive. These newly emerging MRSA are still sensitive to a number of other antibiotics. This results in less broad resistance phenotypes of currently disseminated MRSA. Worth mentioning with regard to diagnostics are also three clinical cases of staphylococcal toxic shock syndrome caused by S. aureus possessing secC and not tst.

Susceptibility to desferrioxamines and other chelators of coagulase-negative staphylococci

A total of 233 staphylococci and micrococci belonging to 17 species were tested for their susceptibility to desferrioxamines B, G and E, respectively. Using an agar diffusion method on iron poor media, all of the S. epidermidis, 12 out of 22 S. hominis and 5 out of 22 S. capitis strains were susceptible to desferrioxamines. Among the S. capitis strains tested, two of them were susceptible to desferrioxamine E and resistant to desferrioxamines B and G. All other staphylococci and micrococci tested were resistant to desferrioxamines B, G and E. Different susceptibility to 5 mM ethylenediaminedi-(o-phenylacetic acid) as an artificial chelator demonstrated the existence of additional iron-supplying systems in staphylococci and micrococci.

Typing of Multiple Isolates of Coagulase-negative Staphylococci from Blood Cultures and Cerebrospinal Fluid in Neonates and Children: An Approach to Discriminate Contaminants

From eight neonates and children suspicious for suffering from septicemia and/or meningitis, coagulase negative staphylococci (CNS) were isolated from multiple blood cultures and from cerebrospinal fluids originating from different punctures. S. epidermidis was the predominant species. By a further typing using plasmid-profiles and exoprotein patterns besides the resistance phenotype, contaminants could be discriminated from the isolates as the probable etiologic agent exhibiting unique reaction patterns. CNS isolated from cases of septicemia together with other bacterial pathogens or from cases of presumed but not confirmed septicemia revealed as different.