Colonization of patients, healthcare workers, and the environment with healthcare-associated Staphylococcus epidermidis genotypes in an intensive care unit: a prospective observational cohort study.

BACKGROUND: During the last decades, healthcare-associated genotypes of methicillin-resistant Staphylococcus epidermidis (HA-MRSE) have been established as important opportunistic pathogens. However, data on potential reservoirs on HA-MRSE is limited. The aim of the present study was to investigate the dynamics and to which extent HA-MRSE genotypes colonize patients, healthcare workers (HCWs) and the environment in an intensive care unit (ICU). METHODS: Over 12 months in 2006-2007, swab samples were obtained from patients admitted directly from the community to the ICU and patients transferred from a referral hospital, as well as from HCWs, and the ICU environment. Patients were sampled every third day during hospitalization. Antibiotic susceptibility testing was performed according to EUCAST guidelines. Pulsed-field gel electrophoresis and multilocus sequence typing were used to determine the genetic relatedness of a subset of MRSE isolates. RESULTS: We identified 620 MRSE isolates from 570 cultures obtained from 37 HCWs, 14 patients, and 14 environmental surfaces in the ICU. HA-MRSE genotypes were identified at admission in only one of the nine patients admitted directly from the community, of which the majority subsequently were colonized by HA-MRSE genotypes within 3 days during hospitalization. Almost all (89%) of HCWs were nasal carriers of HA-MRSE genotypes. Similarly, a significant proportion of patients transferred from the referral hospital and fomites in the ICU were widely colonized with HA-MRSE genotypes. CONCLUSIONS: Patients transferred from a referral hospital, HCWs, and the hospital environment serve as important reservoirs for HA-MRSE. These observations highlight the need for implementation of effective infection prevention and control measures aiming at reducing HA-MRSE transmission in the healthcare setting.

Near absence of methicillin-resistance and pronounced genetic diversity among Staphylococcus epidermidis isolated from healthy persons in northern Sweden.

The main aim of this study was to examine if hospital-associated clones of multidrug-resistant Staphylococcus epidermidis (MDRSE), commonly identified in hospitals in our region, also are spread among healthy persons in the community. A total of 124 isolates of S. epidermidis sampled from subjects attending a Travel health clinic, Umeå, Sweden during 2008 were examined with antibiotic susceptibility testing and pulsed-field gel electrophoresis (PFGE) analysis. Resistance to methicillin or any antibiotic was detected in 2 and 26 of the isolates, respectively. PFGE analysis showed an extensive genetic diversity with 86 different PFGE types, 62 of which were singletons. No isolates belonged to the previously described hospital-associated MDRSE genotypes, indicating that MDRSE by large are confined to the hospital setting in our region. In conclusion, community-associated isolates of S. epidermidis showed a low level of methicillin-resistance and were genetically extremely diverse with no predominating genotype.

Clonality among multidrug-resistant hospital-associated Staphylococcus epidermidis in northern Europe.

Using pulsed-field gel electrophoresis (PFGE) we have previously described the occurrence and possible dissemination of a clone of multidrug-resistant Staphylococcus epidermidis (MDRSE) in 2 hospitals in northern Sweden during 2001-2003. The aims of the present study were to investigate if this clone still persisted, 7 y later, in these 2 hospitals and whether this specific clone was detectable among clinical isolates from 9 other hospitals, 6 Swedish as well as a Norwegian, Danish and a German hospital. In total, 173 clinical isolates of MDRSE isolated during 2003 to 2008 were analysed using PFGE, of which 22 isolates were also characterized by multilocus sequence typing (MLST). Two dominating PFGE types (types A and B) were identified, consisting of 56 (32%) and 38 (22%) isolates, respectively. Type A, which was detected in the Norwegian and all Swedish hospitals, proved indistinguishable to the clone previously identified in 2001-2003 and corresponded with a novel sequence type (ST215). Type B was discovered in the German, Danish and in 7 Swedish hospitals and corresponded with ST2. In conclusion, we have demonstrated the occurrence, persistence and potential dissemination of 2 MDRSE genotypes, including a novel sequence type (ST215), within hospitals in northern Europe.

Treatment of chronic hepatitis B infection: an update of Swedish recommendations.

The main goal for treatment of chronic hepatitis B is to prevent complications such as liver cirrhosis or hepatocellular carcinoma. Knowledge from population studies of the long-term risk of chronic HBV infection, as well as the recent introduction of pegylated interferon and additional nucleoside analogues has changed the therapeutic situation. Recently, a Swedish expert panel convened to update the national recommendations for treatment. The panel recommends treatment for patients with active HBV infection causing protracted liver inflammation or significant liver fibrosis, verified by liver histology. In general, pegylated interferon alpha-2a is recommended as first-line treatment, in particular for HBeAg-positive patients with HBV genotypes A or B. Among nucleoside analogues, entecavir is the first choice and adefovir or tenofovir can be used as alternatives. Lamivudine monotherapy is not recommended due to the high risk of resistance development. Combinations of nucleoside analogues such as tenofovir and lamivudine or emtricitabine are alternatives for patients with non-response or infection with resistant variants, or as first choice for patients with advanced liver disease. Nucleoside analogue treatment should be monitored to detect primary non-response and virological breakthrough. Special recommendations are given for HBV/HIV coinfected patients, immunosuppressed patients, children, and for treatment before and after liver transplantation. The present guideline is translated from Swedish, where it is published on the MPA and RAV websites (www.mpa.se and www.rav.nu.se) including 7 separate papers based on thorough literature search. The complete reference list can be received from the Medical Products Agency upon request.

Molecular epidemiology of Staphylococcus saprophyticus isolated from women with uncomplicated community-acquired urinary tract infection.

Staphylococcus saprophyticus is a common cause of urinary tract infections (UTIs) in women. Little is known about the molecular epidemiology of S. saprophyticus UTIs. In the current study, we compared 76 isolates of S. saprophyticus prospectively isolated from women with uncomplicated UTI participating in a randomized placebo-controlled treatment trial performed in northern Sweden from 1995 to 1997 with 50 strains obtained in 2006 from five different locations in northern Europe with pulsed-field gel electrophoresis (PFGE). The aim was to elucidate the molecular epidemiology of this uropathogenic species and to investigate whether specific clones are associated with UTI in women. A total of 47 different PFGE profiles were detected among the 126 analyzed isolates. Ten clusters consisting of 5 to 12 isolates each showing PFGE DNA similarity of >85% were identified. Several clusters of genetically highly related isolates were detected in the original trial as well as among isolates obtained during 2006 from different locations. In the original trial, clonal persistence was found among 16 of 21 (76%) patients examined in the placebo group at follow-up 8 to 10 days after inclusion, indicating a low spontaneous short-time bacteriological cure rate. We conclude that multiple clones of S. saprophyticus were causing lower UTIs in women. The result suggests that some human-pathogenic clones of S. saprophyticus are spread over large geographical distances and that such clones may persist over long periods of time.

Multiple-locus variable-number tandem repeat analysis for typing of Staphylococcus epidermidis.

We applied a high-resolution PCR-based typing method, multiple-locus variable-number tandem repeat analysis (MLVA), for discrimination of 30 multidrug-resistant clinical isolates of Staphylococcus epidermidis. The results of MLVA were congruent with results obtained by pulsed-field gel electrophoresis (PFGE). MLVA generated discrete character data, and its discriminatory capacity was comparable to that of PFGE.

Spread of clones of multidrug-resistant, coagulase-negative staphylococci within a university hospital.

OBJECTIVE: To detect putative clonal dissemination of multidrug-resistant, coagulase-negative staphylococci (CNS) in a university hospital in northern Sweden. METHODS: All consecutive routine clinical samples from our hospital were screened during two periods (November and December 2001 and September and October 2002) for the presence of multidrug-resistant (defined as resistant to oxacillin, clindamycin, co-trimoxazole, gentamicin, and fusidic acid, but susceptible to vancomycin) isolates of CNS. Genetic similarity between isolates was analyzed using pulsed-field gel electrophoresis (PFGE) and a computer program. RESULTS: Seventy multidrug-resistant isolates from 62 patients were identified, 28 during the 2001 period and 42 during the 2002 period. All isolates except one, which was Staphylococcus haemolyticus, were identified as S. epidermidis. Multidrug-resistant CNS were isolated in samples obtained from 24 different wards. Two subgroups (group A and group B) of S. epidermidis that differed by approximately 40% in PFGE band similarity were identified. Group A consisted of 44 isolates with a PFGE band similarity of greater than 70% that included 6 subgroups consisting of 3 to 16 isolates that expressed a 100% similarity. These isolates were identified during both sampling periods in cultures performed in 18 different wards. A clonal origin could not be excluded for some of the remaining 26 isolates belonging to group B, but none had identical PFGE patterns, suggesting a more diverse origin. CONCLUSION: The results of this study suggest clonal spread of multidrug-resistant CNS within our hospital and that some clones are endemic in the hospital environment.

Prediction of mecA-positive coagulase-negative staphylococci: assessment of different phenotypic methods, breakpoints, culture media and culture conditions.

Sensitivity for the detection of mecA-positive coagulase-negative staphylococci (CNS) was evaluated for different breakpoints of resistance for oxacillin using three different susceptibility tests, either on Mueller-Hinton agar supplemented with 2% NaCl (MH-NaCl agar) or on paper disc method agar supplemented with 5% defibrinated blood (PDM-blood agar). The Etest, multipoint inoculation test and disc diffusion test showed comparable sensitivity (0.96, 0.96 and 0.95, respectively) using an oxacillin breakpoint of > or = 0.5 mg/L or < or = 17 mm for the disc test, after incubation at 35 degrees C for 24 h on MH-NaCl agar. The sensitivity decreased for breakpoints > or = 1 mg/L and when PDM-blood agar was used instead of MH-NaCl agar.