Limiting the spread of penicillin-resistant Streptococcus pneumoniae: experiences from the South Swedish Pneumococcal Intervention Project.

In an attempt to limit the spread of penicillin-resistant pneumococci (PRP), an intervention project was initiated in the Malmöhus County, southern Sweden in January 1995. The ongoing project combines traditional communicable disease control measures and actions aiming at reducing antibiotics consumption. All patients in the county with a nasopharyngeal culture positive for PRP with MIC of Penicillin G > or =0.5 mg/L are followed with nasopharyngeal cultures until PRP-negative. Nasopharyngeal cultures are obtained from family members and close contacts of the index cases. Preschool children carrying PRP are denied attendance at group day-care. From January 1995 to March 1997, 1,038 PRP-carriers (429 index cases and 609 contact cases) were identified. Children aged 1-6 years dominated (83%). Antibiotics sales decreased during the study period, and epidemiologic data indicate that the intervention may have limited the dissemination of PRP in the county, but further evaluation is needed.

Introduction and clonal spread of penicillin- and trimethoprim/sulfamethoxazole-resistant Streptococcus pneumoniae, serotype 9V, in southern Sweden.

As part of an intervention project, all patients in Malmöhus county with a culture positive for penicillin-resistant pneumococci, MIC > or =0.5 mg/L (PRP), have been registered since January 1995. Nasopharyngeal specimens were obtained from family members and close contacts of identified carriers. Children were denied attendance at regular day-care until PRP-negative. In 1995 and 1996, PRP were isolated from 882 individuals, 364 of whom had clinical infection and the remaining of whom were asymptomatic carriers. In 49%, the PRP were of serogroup 9, with MIC of penicillin 0.5-2.0 mg/L and resistance to trimethoprim/sulfamethoxazole. Further analyses with serotyping and genetic fingerprinting suggested strongly that most of the isolates belonged to a single serotype 9V clone. Month by month, an apparently continuous spread appeared from one municipality to a neighboring one. In most communities, the serotype 9V PRP appeared and disappeared within a few months. The active procedures of the intervention project may have limited the spread of the clone in the county.

Screening for human T cell leukaemia/lymphoma virus among blood donors in Sweden: cost effectiveness analysis.

OBJECTIVE: To analyse the cost effectiveness of a national programme to screen blood donors for infection with the human T cell leukaemia/lymphoma virus. DESIGN: Three models for calculating the costs and benefits of screening were developed. The first model analysed the cost of continuously testing all donations; the second analysed the cost of initially testing new blood donors and then retesting them after five years; the third analysed the cost of testing donors only at the time of their first donation. Patients who had received blood components from donors confirmed to be infected with the virus were offered testing. SETTING: Sweden. MAIN OUTCOME MEASURES: Prevalence of infection with the virus among blood donors, the risk of transmission of the virus, screening costs, and the outcome of infection. RESULTS: 648 497 donations were tested for the virus; 1625 samples tested positive by enzyme linked immunosorbent assay. 6 were confirmed positive by western blotting. The prevalence of infection with the virus was 2/100 000 donors. 35 patients who had received blood infected with the virus were tested; 3 were positive. The cost of testing every donation was calculated to be $3.02m (1.88m pounds); this is 18 times higher than the cost of testing new donors only, and only 1 additional positive donor would be discovered in 7 years. Regardless of the model used, screening was estimated to prevent only 1 death every 200 years at a minimum cost of $36m (22.5m pounds). CONCLUSION: Based on these estimates the Swedish National Board of Health and Welfare decided that only new blood donors would be screened for infection with the virus.

[Reduced frequency of resistant pneumococci in Southern Sweden. Community based disease control projects to minimize antibiotic resistance]. / Sänkt frekvens resistenta pneumokocker i Sydsverige. Samhällsbaserat smittskyddsprojekt mot antibiotikaresistens.

In an attempt to limit the spread of penicillin non-susceptible pneumococci (PNSP) in southern Sweden, early in 1995 an intervention project was launched, using a combination of traditional communicable disease control measures and actions aimed at reducing antibiotics consumption. Patients carrying PNSP (penicillin G MIC (0.5 mg/L) are monitored with nasopharyngeal cultures until PNSP-negative. Pre-school children are kept home from group day-care facilities. Previous antibiotic consumption was identified as a risk factor for PNSP carriage. Antibiotics sales decreased during the study period, and epidemiological findings suggest the dissemination of PNSP in the area to have been reduced by the intervention project.

An outbreak of Escherichia coli O157:H7 infection in southern Sweden associated with consumption of fermented sausage; aspects of sausage production that increase the risk of contamination.

A large outbreak of enterohaemorrhagic Escherichia coli (EHEC) infections occurred in southern Sweden during autumn 2002. A matched case-control study was performed and indicated an association between consumption of fermented sausage and EHEC infection (odds ratio 5.4, P<0.002). Pulsed-field gel electrophoresis analysis identified a strain of E. coli O157:H7 in clinical faecal isolates, which was identical to a strain isolated from sausage samples obtained from households of infected individuals. A combination of microbiological and epidemiological results established a link between sausage consumption and the outbreak in 30 out of a total of 39 investigated cases. Contaminated beef was suspected to be the source of infection. Delayed start of fermentation, lack of heat-treatment and a short curing period in cold temperature were identified as the main factors enabling EHEC survival. EHEC can survive throughout the entire production process of fermented sausage if curing conditions are inadequate.

Susceptibility of shigellae to mecillinam, nalidixic acid, trimethoprim, and five other antimicrobial agents.

A total of 199 strains of shigella (1 Shigella dysenteriae, 15 S. boydii, 47 S. flexneri, and 136 S. sonnei) isolated in Malmö, Sweden, within a 3-year period (1977 through January 1980) were tested with the agar plate dilution method for susceptibility to commonly used and newer antimicrobial agents. Mecillinam, nalidixic acid, and trimethoprim had the best in vitro activity. S. flexneri dominated among strains resistant to three or more antimicrobial agents and were less susceptible to ampicillin, chloramphenicol, and doxycycline than other types studied. Sixty-four percent of the strains were resistant to sulfamethoxazole. In vitro, a synergistic effect with trimethoprim was shown only in strains susceptible to sulfamethoxazole. The amidinopenicillin mecillinam was highly active against shigellae. When resistance occurred, it was linked to ampicillin in 17 of 18 strains. The quinolines, here represented by nalidixic acid, might be the drugs of choice.

Controlled comparison of nalidixic acid or lactulose with placebo in shigellosis.

Nalidixic acid and lactulose, respectively, were compared with placebo in a controlled double-blind study in 43 patients with bacteriologically verified shigellosis. All the strains were susceptible to nalidixic acid. Treatment with nalidixic acid resulted in cure in 72%, which was a significantly better result than with placebo (cure in 21%).

Efficacy of the combination pivampicillin/pivmecillinam compared to placebo in the treatment of convalescent carriers of nontyphi Salmonella.

In a randomized, double blind, placebo-controlled study 36 patients aged 16-77 years who had been carriers of nontyphi Salmonella species for 10-21 weeks were given the combination pivampicillin/pivmecillinam or placebo for four weeks in order to eradicate the carrier state. 34/36 patients who fulfilled the criteria for inclusion in the study were evaluable for efficacy, 16 in the pivampicillin/pivmecillinam group and 18 in the placebo group. Seven patients in the pivampicillin/pivmecillinam group had to terminate the treatment after 10-25 days because of adverse reactions, mainly exanthema and nausea. After therapy 8/16 patients treated with pivampicillin/pivmecillinam and 4/18 patients treated with placebo had negative stool cultures for Salmonella species during a mean follow-up time of 13 and 20 weeks, respectively. No abnormalities could be found in those patients who did not respond to therapy except for earlier cholecystectomy in two patients, both in the pivampicillin/pivmecillinam group.

Screening for anti-HIV and HBsAg in pooled sera from a clinical chemistry section as a tool for epidemiological survey.

With the aim of estimating the unknown spread of HIV into the general society, a program for testing pooled routine sera from a clinical chemistry laboratory has been tried. Serum samples obtained from the daily inflow of blood tubes at the Clinical Chemistry Laboratory, Malmö General Hospital, and not labelled as risk samples for blood-borne infection(s), were collected and pools of up to ten sera each were constructed according to a special protocol. All serum pools were screened for anti-HIV and HBsAg. During the 32-months period of the study 3,016 serum pools from men and the same number from women were collected and analysed. These pools together contained sera from 26,468 male and 26,891 female patients, respectively. Altogether 33 male and 2 female pools were found anti-HIV positive. Anti-HIV-positive males appeared in all age groups, without significant difference between the groups. Two female pools from the age group 15 to 24 years were anti-HIV positive; these samples were drawn during the last year of testing. HBsAg was detected in 189 male and 129 female pools. From 1989 to the first half of 1991 the mean anti-HIV prevalence among the male samples investigated was 0.10%, with 95% confidence limits from 0 to 0.25%. If the upper confidence limit is exceeded in the future, this could be a warning of increased spread of HIV of in society.

Previous antibiotic consumption and other risk factors for carriage of penicillin-resistant Streptococcus pneumoniae in children.

As part of the South Swedish Pneumococcal Intervention Project, aimed at reducing the spread of penicillin-resistant pneumococci with MICs for penicillin G > or =0.5 mg/l (PRP), all patients in Malmöhus county, southern Sweden, with a culture positive for PRP were followed up by means of repeated nasopharyngeal cultures until PRP-negative. If a child carrying PRP attended a day-care centre, nasopharyngeal cultures were obtained from the other children and staff. All children screened for PRP carriage in 30 day-care centres with an identified index case were included in the analysis, and several outcome variables (antibiotic consumption during the preceding 6 months, previous health and social situation) were assessed in relation to the end-point PRP carriage. Of 1036 children, 128 were found to be PRP carriers and 908 were PRP non-carriers. The PRP carriers had higher antibiotic consumption, were younger and were more often of male sex than the non-carriers (P<0.05). Consumption of antibiotics during the preceding 6 months was noted in 53% of carriers and 45% of non-carriers (relative risk 1.20, 95% confidence interval 1.01-1.43). When adjusting for age, gender and day-care centre attendance, recent consumption of cotrimoxazole (trimethoprim/sulfamethoxazole) emerged as an independent risk factor for PRP-carriage (relative risk 3.48, 95% confidence interval 1.10-11.07). The PRP-carriage rate in three day-care centres with high cotrimoxazole consumption was significantly higher (24%) than in the other day-care centres (10%) (P<0.005). The results indicate that measures aimed at reducing consumption of antibiotics in general, and cotrimoxazole in particular, may decrease the incidence of penicillin resistance, but such measures are, by themselves, probably not sufficient to halt the spread.

Biological and molecular characterization of subtype D, G, and A/D recombinant HIV-1 transmissions in Sweden.

HIV-1 can be subdivided into at least nine genetic subtypes (A through H and O), but in Europe and the United States there is an almost complete dominance of subtype B. In this study three Swedish HIV-1 transmission chains of subtypes other than subtype B have been biologically and molecularly characterized. The three index cases were African men. The p17 gag and env V3 regions of the HIV-1 genome were directly sequenced from uncultured lymphocytes. Phylogenetic analyses showed that the HIV-1 variants with each transmission group were genetically closely related, supporting the epidemiological information. The individuals in transmission groups I (n = 3) and II (n = 2) carried subtype G and D virus, respectively. Interestingly, all four individuals in transmission group III displayed a recombinant genotype with subtype D p17 gag sequence and subtype A V3 sequence. The biological phenotype of virus isolates (rapid/high, syncytium-inducing; or slow/low, non-syncytium-inducing) correlated with the clinical stage of the infected individual. The study also suggested that the correlation between biological phenotype and V3 genotype that has been established for subtype B HIV-1 variants may be valid also for other subtypes. This study demonstrates that HIV-1 variants of subtypes other than B, including a subtype A/D recombinant, are being transmitted in Europe.

Epidemiologic and molecular investigation of outbreaks of hepatitis C virus infection on a pediatric oncology service.

BACKGROUND: Despite screening of blood donors, hepatitis C virus (HCV) infection can occur in patients who receive multiple transfusions. OBJECTIVE: To clarify mechanisms of nosocomial transmission of HCV. DESIGN: Epidemiologic and molecular analyses of hepatitis C outbreaks. SETTING: Pediatric oncology ward. PATIENTS: Children with cancer. MEASUREMENTS: Epidemiologic analysis, HCV RNA detection, genotyping, and hypervariable region 1 (HVR1) sequencing. RESULTS: Ten cases of infection with acute HCV genotype 3a occurred between 1990 and 1993. Sequencing of HVR1 revealed three related strains. Despite an overhaul of hygiene procedures, a patient infected with genotype 1b generated nine subsequent infected patients in 1994. Several patients had high virus titers and strongly delayed anti-HCV antibody responses. All had permanent intravenous catheters. Multidose vials used for flushing or treatment had probably been contaminated during periods of overlapping treatment. CONCLUSIONS: Contamination of multidose vials was the most likely mode of HCV transmission; therefore, use of such vials should be restricted. Rigorous adherence to hygiene routines remains essential to preventing transmission of bloodborne infections.

Duration of nasopharyngeal carriage of penicillin-resistant Streptococcus pneumoniae: experiences from the South Swedish Pneumococcal Intervention Project.

As a part of an intervention project, all detected carriers of penicillin-resistant pneumococci (PRP) (MIC, > or = 0.5 mg/L) in Malmöhus County, southern Sweden, were followed by means of weekly nasopharyngeal cultures. The median duration of carriage in 678 individuals was 19 days (range, 3-267 days). The duration of carriage was longest in children < 1 year old (median, 30 days) and shortest in adults > 18 years old (median, 14 days). Index cases, whose cultures were performed during an acute infection, were carriers for a mean of 10 days longer than asymptomatic contact cases (P < .05). The PRP spontaneously disappeared from the nasopharynx within 4 weeks in 68%, within 8 weeks in 87%, and within 12 weeks in 94% of the individuals. Other significant risk factors for prolonged carriage were the occurrence of > 6 episodes of acute otitis media (AOM) or first episode of AOM before the age of 1 year (P < .01), the carriage of PRP by other family members (P < .05), and the obtainment of a first positive culture during the winter months (P < .05).

Polyphasic identification of Bacillus and Brevibacillus strains from clinical, dairy and industrial specimens and proposal of Brevibacillus invocatus sp. nov..

Thirty-three clinical, dairy and industrial isolates of aerobic endospore-forming bacteria which were unreactive in routine identification tests were characterized genotypically by using amplified rDNA restriction analysis (ARDRA), 16S rDNA sequencing and DNA-DNA reassociation, and phenotypically by using fatty acid methyl ester (FAME) analysis, SDS-PAGE of whole-cell proteins, API Biotype 100 assimilation tests and 16 other routine phenotypic tests. Three isolates were identified as strains of Bacillus badius, 12 as Brevibacillus agri, including 3 strains associated with an outbreak of waterborne illness, 4 as Brevibacillus centrosporus and 2 as Brevibacillus parabrevis; 12 strains contaminating an antibiotic production plant were recognized as members of a new species, for which the name Brevibacillus invocatus is proposed, with the type strain LMG 18962T (= B2156T = CIP 106911T = NCIMB 13772T).

Acute diarrhoea in adults: aetiology, clinical appearance and therapeutic aspects.

A prospective study of acute diarrhoea was performed during 15 months 1981/1982 and included 731 patients and 240 controls. 43% had been infected abroad. A cluster of travellers with bacterial pathogens was diagnosed in July-August. The following pathogens were found: Campylobacter (18%), enterotoxigenic E. coli (6%), Salmonella spp. (5%), rotavirus (4%), Yersinia enterocolitica (3%), Giardia lamblia (3%), Shigella spp. (2%), Clostridium difficile (2%), enteroviruses (2%) and Entamoeba histolytica (less than 1%). More than 90% of the bacterial or parasitic enteropathogens were detected in the first stool sample. Only 10% of the patients needed hospital treatment and for 97% oral fluids were sufficient. The median duration of diarrhoea was 9 days. No fatal cases occurred and only 2 cases of chronic bowel disease were detected.