Epidemiology and control of meticillin-resistant Staphylococcus aureus in Stockholm County, Sweden, 2000 to 2016: overview of a "search-and-contain" strategy.

To review the epidemiology and measures to control meticillin-resistant Staphylococcus aureus, MRSA, in Stockholm between 2000 and 2016 from the perspective of the Department of Communicable Disease Control and Prevention, Stockholm County Council, Sweden. Age, sex, and place of acquisition of their MRSA on all patients reported to the department were reviewed. Measures for control included surveillance through mandatory reporting of cases, screening patients with risk factors for MRSA, strict adherence to basic nursing hygienic principles, isolation of MRSA positive patients in single rooms in dedicated MRSA wards, and cohorting of staff. An MRSA team was created at the Department of Infectious Diseases, Karolinska University Hospital, for follow-up of all cases. Several administrative meetings and cooperative groups were formed that are still in function. From 2000 to 2016, there were 7373 MRSA cases reported. Healthcare-associated MRSA, HA-MRSA, was successfully controlled, and from 2006 onwards, very limited HA-MRSA transmission or outbreaks occurred. However, incidence increased overall, from 9.5 per 100,000 in 2000 to 37.3 per 100,000 in 2016, due to increase of MRSA acquired abroad and of MRSA acquired in the Swedish community. Surveillance and control measures have been successful in containing HA-MRSA in Stockholm, Sweden, but incidence has increased substantially due to imported cases and spread in the Swedish community. The strategy may be termed "search-and-contain" since screening, infection control, follow-up, and advice on personal hygiene were cornerstones of control, whereas eradication of carriage was not.

Frequent colonization of betahaemolytic streptococci at various body sites including the perineum and anal canal during erysipelas and cellulitis.

Background: Erysipelas and cellulitis are usually caused by betahaemolytic streptococci but the aetiology is often difficult to verify in clinical practice. Methods: Patients with erysipelas or cellulitis were analysed for betahaemolytic streptococci in samples from multiple body sites, including the perineum and the anal canal, during the acute episode and at follow up. Healthy control persons were sampled from the same sites. Results: Betahaemolytic streptococci group A, C or G were identified in 23/28 (82%) patients, most commonly group G. A wound or ulcer, present in 16/28 (57%), was colonized in 8/16 (50%). The perineum and anal canal were colonized in 11/28 (39%) and 10/28 (36%), respectively. At follow-up after about 4 weeks, only 4/28 (14%) were colonized (p<.001). In 39 healthy control persons, no betahaemolytic streptococci group A were found, groups C or G were found in 4/39 (10%). Group B streptococci were more often identified in controls, than in patients,12/39 (31%). Conclusions: Acute episodes of erysipelas or cellulitis are associated with colonization of betahaemolytic streptococci at multiple sites including the perineum and anal canal, in particular serogroup G. This may be important for choice of primary antibiotic therapy and possibilities for prevention of relapses.

Variations in the protective immune response against streptococcal superantigens in populations of different ethnicity.

Superantigens (SAgs) from group A streptococcus (GAS) are potent T cell mitogens, and have been suggested to play a role in severe streptococcal disease. Neutralizing antibodies protect against SAg-mediated disease and their levels should therefore be inversely related to severe streptococcal infection. Neutralizing anti-SAg titers in patients with severe GAS infection and patients without disease were compared in two separate groups. The first group comprised patients with invasive GAS disease from New Zealand European, Maori, and Pacific Island descent. The second group comprised Aboriginal Australian individuals with rheumatic heart disease and/or a past history of acute rheumatic fever. Patients sera were tested for their ability to neutralize T cell mitogenicity of recombinant streptococcal SAgs as a measure of functional SAg-neutralizing antibody concentration. In both studies, no inverse correlation was observed between disease and the level of serum SAg-neutralizing activity. Notably, much higher levels of natural immunity to all streptococcal SAgs were found in New Zealand Maori, New Zealand Pacific Island, and Aboriginal Australian individuals, suggesting a high degree of natural exposure and seroconversion in these groups compared to the New Zealand European cohort. Levels of serum antibodies against SAgs could not be used to predict disease susceptibility in groups with existing high levels of SAg-neutralizing antibodies.

Group A streptococcal infections in Sweden: a comparative study of invasive and noninvasive infections and analysis of dominant T28 emm28 isolates.

Surveillance of group A streptococcus (GAS) infections in Sweden during 1996-1997 indicated that T28 isolates were dominant, whereas T1M1 infections were uncommon. Circulating T28 isolates were nearly all emm28, MLST52, and these clones had also been prevalent 10 years earlier. Isolates from invasive and noninvasive infections were of similar types and prevalences. The average national incidence of invasive episodes was 2.9/100,000 population but varied between 0 and 8.3/100,000 population in different counties. It increased markedly with age, reaching 22.9 episodes/100,000 among people aged > or =90 years. The incidence of puerperal sepsis was higher than expected (22.4/100,000 of those at risk), with 1 death. Overall mortality was 16% and was associated with preexisting chronic disease (P=.002). Streptococcal toxic shock syndrome (STSS) developed in approximately 15% of patients with invasive episodes, with a mortality rate of 45%. The use of nonsteroidal anti-inflammatory drugs was not found to be associated with the development of STSS.