Antimicrobial susceptibility of invasive pneumococcal isolates from a region in south-west Sweden 1998-2001.

Invasive disease caused by antibiotic resistant pneumococci is a worldwide problem. All invasive pneumococcal strains in an area of south-west Sweden with 1.7 million inhabitants were collected prospectively during 1998-2001. Minimum inhibitory concentrations (MICs) were determined by E-test and correlated to serotypes and clinical characteristics. Of 827 strains, 744 (90%) were susceptible (S) to all agents tested and 83 (10%) were indeterminate (I) or resistant (R) to at least 1 agent. 22 isolates (2.7%) were I to penicillin (MIC >0.06 to < or = 1.0 mg/l), but none were R (MIC >1.0 mg/l). Numbers and proportions of decreased susceptibility against other agents tested were as follows: erythromycin R: 30 (3.6%), clindamycin R: 6 (0.7%), tetracycline R: 16 (1.9%), moxifloxacin R: 1 (0.1%), cotrimoxazole I: 17 (2%) and R: 31(4%). Non-susceptibility to at least 1 agent was not correlated with age, clinical manifestation, underlying diseases and outcome. The serotype distribution differed between non-susceptible and susceptible strains. The serotypes in the 7-valent pneumococcal conjugate vaccine covered 42% of all infections and 73% of those caused by non-susceptible strains. In conclusion, the impact of antibiotic resistance in invasive pneumococcal disease remains limited in south-west Sweden.

Staphylococcus aureus throat colonization is more frequent than colonization in the anterior nares.

The aim of this study was to determine the frequency and persistence of Staphylococcus aureus carriage in the throat in relation to anterior naris carriage. By use of a sensitive enrichment broth, S. aureus was cultured from the two sites from 259 patients upon admission to an orthopedic ward and from 87 staff members of the same ward. The throat was the most common carriage site in both groups. Forty percent of the patients and 54% of the staff were positive for S. aureus in the throat, compared to 31% and 36%, respectively, in the anterior nares. To determine the persistence of carriage, 67 individuals were repeatedly sampled from the anterior nares and the throat over 2 years (5 to 10 sampling occasions; mean, 7.8). The majority, 58% (39/67), were defined as persistent carriers of S. aureus, considering culture results from both sites. Of the 39 persistent carriers, 15 individuals were culture positive from only the throat on more than half of the sampling occasions (these are called preferential throat carriers) while only 5% (two individuals) were preferential anterior naris carriers by use of the same definition. Typing of the collected S. aureus isolates by pulsed-field gel electrophoresis revealed that the same strain of S. aureus was present, over time, in the throat of an individual at least to the same extent as in the anterior nares. Throat carriage was at least as persistent as carriage in the anterior nares.

Serotypes of Streptococcus pneumoniae isolated from blood and cerebrospinal fluid related to vaccine serotypes and to clinical characteristics.

Pneumococci isolated from blood and cerebrospinal fluid from 1998 to 2001 in 2 counties in south-west Sweden were serotyped with the capsular reaction test. Of the 836 strains, 353 (42%), 598 (72%) and 789 (94%) belonged to serotypes included in the 7- and 11-valent pneumococcal conjugate vaccines and in the 23-valent polysaccharide vaccine, respectively. The most common serotype was type 1 (119 isolates) followed in descending frequency by serotypes 7F, 9V, 14, 4 and 12F (90-49 isolates per serotype). The coverage rates of the 7- and 11-valent conjugate vaccines among 58 strains isolated from children and adolescents 0-19 y of age were 46% and 93%, respectively. A comparison of clinical characteristics of infections caused by different serotypes showed that types 1 and 7F were less commonly associated with severe underlying diseases, that patients infected with these serotypes were younger than the average and, thus, had a lower case-fatality rate.

Is the increase in notifications of Chlamydia trachomatis infections in Sweden the result of changes in prevalence, sampling frequency or diagnostic methods?

Based on clinical and laboratory surveillance data, trends in the incidence rates of genital Chlamydia trachomatis infections in Sweden between 1991 and 1999 were analysed according to age group and sex. The influence of changes in laboratory methods on the reported infections was assessed. After a decrease in the incidence rate of infection of 36% between 1991 and 1994, followed by a period of stability, a 20% increase was observed between 1997 and 1999 (from 157 to 189/100,000). Between 1991 and 1999 the female:male ratio decreased from 1.7 to 1.4. Incidence rates started to increase in 1994 in the 15-19 y age group for both sexes. Crude Chlamydia positivity increased from 4.1% (352,050 people tested) in 1994 to 5.4% (305,946 people tested) in 1999. This increase in Chlamydia positivity was seen both in laboratories that had changed to more sensitive methods and in those that had not. Changes in laboratory methods can therefore only partially explain the increase in notified cases. Increased screening of men may have contributed to the increase, but rising incidence rates in all young age groups of both sexes suggest a true increase in prevalence.