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

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.

Emergence of a new community acquired MRSA strain in Germany.

Analysis of community-acquired methicillin-resistant Staphylococcus aureus (c-MRSA) from Germany producing the Panton-Valentine leukocidin revealed a unique SmaI-macrorestriction pattern, different from epidemic nosocomial strains. This molecular pattern corresponds to those shown in c-MRSA strains from other countries in the European Union. All isolates exhibited resistance to fusidic acid, which is coded by the far-1 gene. From data on geographical dissemination and time of occurrence, this strain appears to have emerged in Germany in the second half of 2002, and so an already wider dissemination is likely. The emergence of MRSA with resistance to fusidic acid is a first sign of the emergence of a PVL-positive MRSA clone.

[Methicillin-resistant Staphylococcus aureus in long-term care facilities for the aged in Frankfurt am Main, Germany, in 1999]. / MRSA-Besiedelung bei Bewohnern von Alten- und Pflegeheimen sowie bei Patienten einer geriatrischen Rehabilitationsklinik in Frankfurt am Main, 1999.

In recent years problems with multiple resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) in hospitals have been increasing world-wide. Moreover, nursing home residents have also been found to be colonised with MRSA. In 1999, the Robert Koch Institute, Berlin inaugurated a multicenter study on the prevalence of MRSA colonisation in residents of old-age nursing homes in Germany. Here, the data from the city of Frankfurt will be reported. COLLECTIVES AND METHODS: With the informed consent of 359 residents from 7 old-age pensioners' homes and 42 patients of a geriatric rehabilitation unit, nasal and pharyngeal swaps were taken and tested for MRSA. Age, sex, duration of the stay in the home, former hospital admissions, acute and chronic diseases and medical devices such as urinary catheters were asked using a questionnaire. In addition including 150 employees (mainly nurses) of these institutions were tested for MRSA as well. RESULTS: None of the employees tested were MRSA-positive. MRSA was found in 10 out of 401 residents/patients (2.4 %), i. e. 4.8 % of the patients and 2.2 % of the residents. As risk factors for colonisation of the residents could be found: male sex (Odds ratio 4.7, 95 % confidence interval 95CI 1.3-16.9), stay in the institution for less than 1 year (OR = 17.4; 95CI: 2.2-141) and former MRSA-colonisation (OR = 24.2; 95CI: 3.9-152). In addition, we got hints that former hospital admission was a risk factor for colonisation with MRSA (OR = 3; 95CI: 0.6-14.4). Residents with ulcus, decubiti and peripheral circulatory disorder were at double risk for MRSA colonisation (not significant). DISCUSSION AND CONCLUSIONS: The prevalence of MRSA colonisation in the residents of the old-age pensioners homes in Frankfurt am Main, Germany, was 2.4 %, which is (still?) low. There were no hints available for the spread of MRSA within the homes, although in 7 of 8 MRSA-positive residents MRSA colonisation was not known previously, so that no special hygienic regime was applied. Therefore, US-American and British guidelines for the control of MRSA in nursing homes were confirmed: a good hygienic regime, especially correct hand hygiene is the most important measure to prevent the spread of MRSA within the nursing homes. In general, isolation of the colonised residents is not necessary, unless in very special individual cases.

Characteristics of a new epidemic MRSA in Germany ancestral to United Kingdom EMRSA 15.

In 1996 a new epidemic MRSA emerged in three hospitals North of Berlin. This strain, Barnim epidemic MRSA, was isolated in 15 hospitals in Northern Germany in 1997 and 29 hospitals throughout Germany in 1998. Isolates of this clone are non-typeable by phages, its resistance phenotype is PEN, OXA, ERY, CLI, CIP (genotype: mecA, ermC, mutations in grlA and gyrA). The Sma I macrorestriction pattern corresponds to particular phage group II strains which is confirmed by the 16S-23S rRNA gene spacer pattern. Isolates of this clone differ by less than three Sma I macrorestriction fragments from isolates of the EMRSA15 clone from the United Kingdom, the most common epidemic MRSA isolates in the United Kingdom in recent years. Both epidemic strains produce enterotoxin C and possess the sec determinant for this toxin, the configuration of the mec regulon is mecI-, mecRB+, mecRC+. Both share the same Alu I pattern of PCR amplimers of the 3' end region of the coagulase gene. EMRSA 15 and Barnim EMRSA share a common multilocus sequence type indicating a recent, shared evolutionary origin.

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.

Methicillin resistant Staphylococcus aureus in German hospitals develop narrower patterns of antimicrobial resistance.

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in German hospitals has continued to increase, but the range of anti-microbials to which they are resistant has decreased. The trend cannot be attributed to changes in antibiotic consump

Widespread dissemination of epidemic MRSA in German hospitals.

Strains of Staphylococcus aureusresistant to multiple antibiotics, including those resistant to methicillin (MRSA), present a major problem in the control of hospital acquired infections. Some strains show a definite capacity for spread once introduced in

[Outbreak of infection with methicillin-resistant Staphylococcus aureus (MRSA) in an orthopedic septic care unit--measures for eradication and subsequent colonization studies]. / Ausbruch von Infektionen mit Methicillin-resistenten Staphylococcus aureus (MRSA) auf einer orthopädisch-septischen Station--Massnahmen zur Eradikation und nachfolgende Besiedlungsstudien.

An outbreak due to a methicillin-resistant S. aureus (MRSA) strain in an orthopaedic septic care unit was observed. 17 patients developed wound infections. Stronger regime of hygiene and chemotherapy and new technics of operations controlled the outbreak within 5 months. Studies of colonisation were performed at the care unit in march, june and august 1992. 618 isolates were investigated from patients, personnel and their environment. The frequencies of detected MRSA diminished from 30% in march only to 22% in august 1992. The long time persistence of endemic MRSA in a care facility was evident from the presence of MRSA even 5 months after the last infection.

[Analysis and conclusions regarding the epidemic spread of methicillin resistant S. aureus]. / Analysen und Schlussfolgerungen zur epidemischen Verbreitung von Methicillin-resistenten S. aureus.

Increasing dissemination of Methicillin-resistant S. aureus (MRSA) calls for a more consequent examination of the causal mechanisms. Experiences and results of analysis of three different outbreaks caused by MRSA are described. In summary it is shown that MRSA are especially epidemic virulent and persist over a long range of time in a care unit. Main reasons for these outbreaks obviously were mistakes in hospital hygiene and an inappropriate antibiotic prophylaxis. Predisposed inpatients suffer from severe infections. Interregional dissemination of MRSA observed is mainly due to the transfer of patients between hospitals. Optimization of hospital hygiene especially isolated or cohort nursing of affected patients as well as restriction of antibiotic prophylaxis and therapy are crucial measures against the dissemination of MRSA. For success of these measures information and motivation of staff are necessary.

Iron supply of staphylococci and of micrococci by alpha-ketoacids.

Most of 232 strains of coagulase-negative staphylococci (CNS) belonging to 16 species, and nine strains of micrococci belonging to four species, could be distinguished by their growth on an iron-poor nutrient medium. alpha-Keto-/alpha-hydroxyacids, as primary metabolites, facilitated iron supply to CNS and micrococci under various iron-limited conditions, as detected by different bioassay methods. Twelve selected CNS strains and two micrococcal strains produced significant amounts of alpha-ketoacids in iron-poor liquid nutrient media. In particular, strains of Staphylococcus cohnii, S. xylosus and S. lentus unable to grow on iron-poor media, produced high amounts of pyruvic acid and alpha-ketoglutaric acid. In bioassays, the selected CNS strains being siderophore indicator strains were fed with alpha-ketoacids at different levels of iron limitation. Strains able to grow under iron deprivation appeared to produce additional siderophores such as staphyloferrins under iron stress. alpha-Keto-/alpha-hydroxyacids may be additionally active in the iron supply of CNS and micrococci.

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.

[Nosocomial infections with the detection of Staphylococcus aureus in an average hospital--an 11-year analysis]. / Nosokomiale Infektionen mit Nachweis von Staphylococcus aureus in einem mittleren Krankenhaus--eine 11-Jahres-analyse.

Nosocomial infections over an 11 years period were monitored prospectively in a district hospital. A total of nosocomial infections among 162.197 patients discharged from 1980-1990 were analyzed. The incidence rate of nosocomial infections was 3.6%. The predominant isolates were Escherichia coli and Staphylococcus aureus (11%). The highest rates of S. aureus infections were established in wound infections and skin and mucosal infections at surgery, gynaecology and paediatrics departments. The number of multiply resistant S. aureus strains has decreased and those of sensitive isolates has increased. 72% of 652 S. aureus isolates have been typed by phage typing and biotyping. Statistical analysis could not establish a significant relationship between phage patterns and nosocomial infections. The spectrum of phage patterns of these nosocomial strains was the same as those of the endogenous colonization of men. Nosocomial outbreaks could not been realized.

Analysis of nosocomial outbreaks with multiply and methicillin-resistant Staphylococcus aureus (MRSA) in Germany: implications for hospital hygiene.

Two 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 phage-patterns, 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.

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.

[Clonal spreading of a multidrug resistance Citrobacter freundii strain at a neonatal intensive care unit]. / Untersuchungen zur klonalen Verbreitung eines multiresistenten Citrobacter-freundii-Stammes auf einer neonatologischen Intensivtherapiestation.

This paper reports on the epidemic spreading of a multiresistant Citrobacter (C.) freundii strain at a neonatal intensive care unit. A premature baby of the 27th week of pregnancy died from septic shock caused by this strain. According to the result of a statistical analysis of risk factors a connection between the colonization of neonates and the feeding with an enteral feeding tube was probably. This suspicion could be confirmed by the detection of the multiresistant strain in the infant formula. Plasmid analysis, examination of outer membrane proteins and lipopolysaccharides of these C. freundii strains demonstrated the identity of all isolates. The resistance to antibiotics of this multiresistant C. freundii clone was determined by a plasmid belonging to incompatibility group C with a molecular weight of 110 MDa. This plasmid was involved also in other nosocomial outbreaks. It persisted more than 7 years in the hospital flora of the intensive care unit.