International links between Streptococcus pneumoniae vaccine serotype 4 sequence type (ST) 801 in Northern European shipyard outbreaks of invasive pneumococcal disease

BACKGROUND

Pneumococcal disease outbreaks of vaccine preventable serotype 4 sequence type (ST)801 in shipyards have been reported in several countries. We aimed to use genomics to establish any international links between them.

METHODS

Sequence data from ST801-related outbreak isolates from Norway (n = 17), Finland (n = 11) and Northern Ireland (n = 2) were combined with invasive pneumococcal disease surveillance from the respective countries, and ST801-related genomes from an international collection (n = 41 of > 40,000), totalling 106 genomes. Raw data were mapped and recombination excluded before phylogenetic dating.

RESULTS

Outbreak isolates were relatively diverse, with up to 100 SNPs (single nucleotide polymorphisms) and a common ancestor estimated around the year 2000. However, 19 Norwegian and Finnish isolates were nearly indistinguishable (0-2 SNPs) with the common ancestor dated around 2017.

CONCLUSION

The total diversity of ST801 within the outbreaks could not be explained by recent transmission alone, suggesting that harsh environmental and associated living conditions reported in the shipyards may facilitate invasion of colonising pneumococci. However, near identical strains in the Norwegian and Finnish outbreaks does suggest that transmission between international shipyards also contributed to those outbreaks. This indicates the need for improved preventative measures in this working population including pneumococcal vaccination.

Utility of oropharyngeal real-time PCR for S. pneumoniae and H. influenzae for diagnosis of pneumonia in adults

A lack of sensitive tests and difficulties obtaining representative samples contribute to the challenge in identifying etiology in pneumonia. Upper respiratory tract swabs can be easily collected and analyzed with real-time PCR (rtPCR). Common pathogens such as S. pneumoniae and H. influenzae can both colonize and infect the respiratory tract, complicating the interpretation of positive results. Oropharyngeal swabs were collected (n = 239) prospectively from adults admitted to hospital with pneumonia. Analysis with rtPCR targeting S. pneumoniae and H. influenzae was performed and results compared with sputum cultures, blood cultures, and urine antigen testing for S. pneumoniae. Different Ct cutoff values were applied to positive tests to discern colonization from infection. Comparing rtPCR with conventional testing for S. pneumoniae in patients with all tests available (n = 57) resulted in: sensitivity 87 %, specificity 79 %, PPV 59 % and NPV 94 %, and for H. influenzae (n = 67): sensitivity 75 %, specificity 80 %, PPV 45 % and NPV 94 %. When patients with prior antimicrobial exposure were excluded sensitivity improved: 92 % for S. pneumoniae and 80 % for H. influenzae. Receiver operating characteristic curve analysis demonstrated for S. pneumoniae: AUC = 0.65 (95 % CI 0.51-0.80) and for H. influenzae: AUC = 0.86 (95 % CI 0.72-1.00). Analysis of oropharyngeal swabs using rtPCR proved both reasonably sensitive and specific for diagnosing pneumonia caused by S. pneumoniae and H. influenzae. This method may be a useful diagnostic adjunct to other methods and of special value in patients unable to provide representative lower airway samples.

Changing epidemiology of group B streptococcal infections among adults in Iceland: 1975-2014

We studied the bacterial characteristics and incidence of invasive infections caused by group B streptococci (GBS) in adults in Iceland in 1975-2014. A total of 145 isolates were characterized by serotyping, antimicrobial susceptibility, multilocus sequence typing and surface protein gene profiling. Disease incidence increased during the studied period (p <0.001), reaching 2.17 cases/100 000 person-years in 2013-14. Overall, serotype Ia was the most frequently found (23%), but serotypes Ib, II, III and V showed similar prevalence (14%-17%). Although there were notable changes in the proportion of most serotypes during the study period, only the decline of serotype III was statistically supported (p = 0.003) and was reflected in a decrease of clonal complexes CC17 and CC19 that included most serotype III isolates (p <0.04). On the other hand, the increase in frequency of CC1 was caused by two lineages expressing distinct serotypes: ST1/V/alp3 and ST196/IV/eps. Underlying the relative stability of serotype Ia were major changes in the lineages expressing this serotype, with an increase in the relative importance of CC23, including both ST23/Ia/eps and ST24/Ia/bca lineages, and a decrease in CC7. Nine cases of invasive GBS disease were caused by ST7, of possible zoonotic origin. All isolates were susceptible to penicillin. Rates of erythromycin and clindamycin resistance were 8.3% and 9.7%, respectively. An over-representation of resistance solely to clindamycin was associated with the unusual lsaC gene and serotype III ST19/rib lineage (p <0.001).

Invasive infections due to Streptococcus pyogenes: seasonal variation of severity and clinical characteristics, Iceland, 1975 to 2012

Epidemiology and clinical characteristics of invasive Group A streptococcal infections (IGASI) are highly variable. Long-term studies are needed to understand the interplay between epidemiology and virulence. In a population-based study of IGASI in Iceland from 1975 to 2012, 288 cases were identified by positive cultures from normally sterile body sites. Charts were reviewed retrospectively and emm-types of viable Streptococcus pyogenes isolates (n=226) determined. Comparing the first and last decade of the study period, IGASI incidence increased from 1.09 to 3.96 cases per 100,000 inhabitants per year. The most common were emm types 1 (25%), 28 (11%) and 89 (11%); emm1 strains were most likely to cause severe infections. Infections in adults were significantly more likely to be severe during the seasonal peak from January to April (risk ratio: 2.36, 95% confidence interval: 1.34–4.15). Significant seasonal variability in severity was noted among patients with diagnosis of sepsis, respiratory infection and cellulitis, with 38% of severe infections in January to April compared with 16% in other months (p<0.01). A seasonal increase in severity of IGASI suggested that generalised seasonal increase in host susceptibility, rather than introduction of more virulent strains may play a role in the pathogenesis of these potentially fatal infections.

Invasive infections due to Streptococcus pyogenes: seasonal variation of severity and clinical characteristics, Iceland, 1975 to 2012

Epidemiology and clinical characteristics of invasive Group A streptococcal infections (IGASI) are highly variable. Long-term studies are needed to understand the interplay between epidemiology and virulence. In a population-based study of IGASI in Iceland from 1975 to 2012, 288 cases were identified by positive cultures from normally sterile body sites. Charts were reviewed retrospectively and emm-types of viable Streptococcus pyogenes isolates (n=226) determined. Comparing the first and last decade of the study period, IGASI incidence increased from 1.09 to 3.96 cases per 100,000 inhabitants per year. The most common were emm types 1 (25%), 28 (11%) and 89 (11%); emm1 strains were most likely to cause severe infections. Infections in adults were significantly more likely to be severe during the seasonal peak from January to April (risk ratio: 2.36, 95% confidence interval: 1.34–4.15). Significant seasonal variability in severity was noted among patients with diagnosis of sepsis, respiratory infection and cellulitis, with 38% of severe infections in January to April compared with 16% in other months (p<0.01). A seasonal increase in severity of IGASI suggested that generalised seasonal increase in host susceptibility, rather than introduction of more virulent strains may play a role in the pathogenesis of these potentially fatal infections.

Epidemiology of penicillin-non-susceptible pneumococci in Iceland, 1995-2010

OBJECTIVES

The first penicillin-non-susceptible pneumococci (PNSP) were identified in Iceland in 1988. A rapid increase followed, associated with expansion of a single multiresistant clone, Spain(6B)-2, peaking at 19.8% in 1993. After interventions led to reduced antimicrobial use in children, the prevalence of PNSP decreased until 1995. The aim of this study was to follow the evolution of PNSP from 1995 to 2010, the period preceding the introduction of conjugated pneumococcal vaccines into the vaccination programme.

METHODS

The laboratory at the Landspitali University Hospital serves ∼ 85% of the Icelandic population. All pneumococci isolated from 1995 to 2010 (n = 13,937) were stored (-80 °C). Oxacillin-resistant isolates were serotyped and penicillin MICs were determined. Selected strains were genotyped by PFGE and multilocus sequence typing.

RESULTS

In 1995, the rate of PNSP was 24.2%, declining to 13.6% in 2001, and then increasing to 38.6% in 2010. Similar changes were observed for resistance to erythromycin and tetracycline. In 1995, 60.7% of PNSP were serotype 6B, mainly the Spain(6B)-2 clone, declining to 5.7% in 2010. PNSP of serotype 19F rapidly increased after 2004 to comprise 85.8% of all serogrouped PNSP in 2010, with most isolates belonging to a single multiresistant PFGE clone identified as sequence type (ST) 271 and ST1968, representing single- and double-locus variants of the international clone Taiwan(19F)-14, respectively. PNSP were most common among young children, from the nasopharynx, middle ear and lower respiratory tract.

CONCLUSIONS

The epidemiology of PNSP was dominated by two multiresistant clones. The second expanded rapidly when the first one was disappearing, causing higher antibiotic resistance rates among pneumococci than seen before in Iceland.

Prevalence and genetic relatedness of antimicrobial-resistant Escherichia coli isolated from animals, foods and humans in Iceland

The prevalence of resistant bacteria in food products in Iceland is unknown, and little is known of the prevalence in production animals. The aim of this study was to investigate the prevalence and genetic relatedness of antimicrobial-resistant Escherichia coli from healthy pigs and broiler chicken, pork, broiler meat, slaughterhouse personnel and outpatients in Iceland. A total of 419 E. coli isolates were tested for antimicrobial susceptibility using a microbroth dilution method (VetMIC), and resistant strains were compared using pulsed-field gel electrophoresis (PFGE). All samples were screened for enrofloxacin-resistant strains with selective agar plates. The resistance rates among E. coli isolates were moderate to high from caecal and meat samples of pigs (54.1% and 28%), broilers (33.6% and 52%) and slaughterhouse personnel (39.1%), whereas isolates from outpatients showed moderate resistance rates (23.1%). Of notice was resistance to quinolones (minimum inhibitory concentrations: nalidixic acid > or = 32, ciprofloxacin > or = 0.12 and enrofloxacin > or = 0.5), particularly among broiler and broiler meat isolates (18.2% and 36%), as there is no known antimicrobial selection pressure in the broiler production in Iceland. The majority (78.6%) of the resistant E. coli isolates was genotypically different, based on PFGE fingerprint analyses and clustering was limited. However, the same resistance pattern and pulsotype were found among isolates from broiler meat and a slaughterhouse worker, indicating spread of antimicrobial-resistant E. coli from animals to humans. Diverse resistance patterns and pulsotypes suggest the presence of a large population of resistant E. coli in production animals in Iceland. This study gives baseline information on the prevalence of antimicrobial-resistant E. coli from production animals, and their food products in Iceland and the moderate to high resistance rates emphasize the need for continuing surveillance. Further studies on the origin of the resistant strains and the genetic relatedness of strains of different origin are needed.

Emergence and spread of vancomycin resistance among enterococci in Europe

Vancomycin-resistant enterococci (VRE) first appeared in the late 1980s in a few European countries. Nowadays, six types of acquired vancomycin resistance in enterococci are known; however, only VanA and to a lesser extent VanB are widely prevalent. Various genes encode acquired vancomycin resistance and these are typically associated with mobile genetic elements which allow resistance to spread clonally and laterally. The major reservoir of acquired vancomycin resistance is Enterococcus faecium; vancomycin-resistant Enterococcus faecalis are still rare. Population analysis of E. faecium has revealed a distinct subpopulation of hospital-acquired strain types, which can be differentiated by molecular typing methods (MLVA, MLST) from human commensal and animal strains. Hospital-acquired E. faecium have additional genomic content (accessory genome) including several factors known or supposed to be virulence-associated. Acquired ampicillin resistance is a major phenotypic marker of hospital-acquired E. faecium in Europe and experience has shown that it often precedes increasing rates of VRE with a delay of several years. Several factors are known to promote VRE colonisation and transmission; however, despite having populations with similar predispositions and preconditions, rates of VRE vary all over Europe.

Increasing multidrug resistance and limited treatment options: situation and initiatives in Europe

Antimicrobial resistance due to the continuous selective pressure from widespread use of antimicrobials in humans, animals and agriculture has been a growing problem for decades. In 2001, European Union Ministers of Health adopted Council Recommendations on the prudent use of antimicrobial agents in human medicine. This issue of Eurosurveillance is the second one this month dedicated to antimicrobial resistance, in connection with the first-ever European Antibiotic Awareness Day - a European Union (EU) health initiative involving all key players to increase awareness of Europeans about antimicrobial resistance and prudent use of antibiotics.

Emergence and spread of vancomycin resistance among enterococci in Europe

Nowadays, six types of acquired vancomycin resistance in enterococci are known; however, only VanA and to a lesser extent VanB are widely prevalent. Various genes encode acquired vancomycin resistance and these are typically associated with mobile genetic elements which allow resistance to spread clonally and laterally. The major reservoir of acquired vancomycin resistance is Enterococcus faecium; vancomycin-resistant Enterococcus faecalis are still rare. Population analysis of E. faecium has revealed a distinct subpopulation of hospital-acquired strain types, which can be differentiated by molecular typing methods (MLVA, MLST) from human commensal and animal strains. Hospital-acquired E. faecium have additional genomic content (accessory genome) including several factors known or supposed to be virulence-associated. Acquired ampicillin resistance is a major phenotypic marker of hospital-acquired E. faecium in Europe and experience has shown that it often precedes increasing rates of VRE with a delay of several years. Several factors are known to promote VRE colonisation and transmission; however, despite having populations with similar predispositions and preconditions, rates of VRE vary all over Europe.

Risk factors and outcome in ICU-acquired infections

BACKGROUND

Nosocomial infections are common in intensive care units (ICU). The objectives of this study were to determine risk factors of ICU-acquired infections, and potential mortality attributable to such infections.

METHODS

An observational study was performed in a 10-bed multidisciplinary ICU. For a period of 27 months, all patients admitted for >or=48 h were included. Infections were diagnosed according to Centers for Disease Control and Prevention definitions. Airway colonization was explored by molecular typing. Risk factors for infection were determined by multivariable logistic regression. Survival was analyzed with time-varying proportional hazards regression.

RESULTS

Of 278 patients, 81 (29%) were infected: urinary tract infections in 39 patients (14%), primary bloodstream infections in 25 (9%), surgical site infections in 22 (8%) and pneumonia in 21 (8%). Of the total of 147 episodes, Gram-negative bacilli were isolated in 90, Gram-positive cocci in 49 and Candida sp. in 25. Risk factors for pneumonia were mechanical ventilation [odds ratio (OR=7.9, CI 1.8-35), lack of enteral nutriment (OR=8.0, CI 1.4-45) and length of time at risk (OR=1.8, CI 1.2-2.8), while gastric acid inhibitors did not affect the risk (OR=0.99, CI 0.32-3.0). Transmission of bacteria from the stomach to the airway was not confirmed. The risk of death was increased as patients were infected with pneumonia [hazard ratio (HR)=3.6; CI: 1.6-8.1], or primary bloodstream infection (HR=2.5; CI: 1.2-5.4), independent of age and disease severity.

CONCLUSIONS

Mortality was increased by ICU-acquired pneumonia and primary bloodstream infections. Our findings did not support the gastro-pulmonary hypothesis of ICU-acquired pneumonia. The proposition that blood transfusions increase the risk of ICU-acquired nosocomial infections was not supported.

Onychomycosis in Icelandic children

BACKGROUND

Onychomycosis is a rare disorder in children. Few studies exist on the incidence or prevalence of onychomycosis in children.

OBJECTIVE

To examine the epidemiology of childhood onychomycosis in Iceland during the period 1982-2000.

METHODS

Results from all mycological samples taken from children in Iceland from 1982 to 2000 were examined. Information about the requesting physician, unique social security number, date of birth, sex, results of culture and microscopy were registered. Growth of a dermatophyte was taken as an indication of a case of onychomycosis.

RESULTS

During the period 1982-2000 a total of 493 samples from 408 Icelandic children, aged 0-17 years, were examined. Dermatophytes were cultured from 148 (30.0%) samples. During the period 1982-85, the mean annual incidence of positive cultures was 1.65 per 100,000, increasing to 21.30 per 100,000 for the years 1996-2000. Trichophyton rubrum was the dominating organism and was found in 102/148 cases positive for the growth of a dermatophyte. The incidence of positive dermatophyte cultures increased with age and was found in eight children aged 0-4, and in 57 children aged 10-14 years.

CONCLUSION

Onychomycosis is rare in children, but increases with age. It seems that onychomycosis increased during the study period, but it is not clear if this was due to a true increase in the prevalence of onychomycosis or an increased awareness of onychomycosis, or both.

Nationwide study of recurrent invasive pneumococcal infections in a population with a low prevalence of human immunodeficiency virus infection

Recurrent invasive infections caused by Streptococcus pneumoniae are rare, and often considered to be indicative of serious underlying illness. However, the prevalence of this problem, and the relevance of specific predisposing conditions, can be hard to assess, since many of the studies are based on specific risk groups. A population-based study of recurrent invasive pneumococcal disease in Iceland during the 30-year period 1975-2004 was performed. Clinical information, including mortality and vaccine use, was analysed retrospectively. Invasive pneumococcal isolates were serotyped and susceptibility testing was performed. During this period, 36 (4.4%) of 819 patients who survived an initial infection experienced recurrence, with a median time between episodes of 9.7 months. Pneumonia with bacteraemia was the most common clinical diagnosis (48% of cases), followed by bacteraemia without a clear focus (21%) and meningitis (13%). Most (94%) of the patients had identifiable predisposing conditions, most commonly, multiple myeloma in adults, and antibody deficiencies in children. Compared with children, adults were more likely to present with pneumonia (65% vs. 18%; p 0.0001). No significant change in the 30-day mortality rate was observed during the three decades of the study. Only 26% of eligible patients received pneumococcal vaccination. Patients with recurrent invasive pneumococcal disease should be investigated thoroughly for underlying diseases. Greater use of pneumococcal vaccines should be encouraged among high-risk patients. More effective preventive and therapeutic measures are needed to improve outcomes.

Streptococcal throat infections and exacerbation of chronic plaque psoriasis: a prospective study

BACKGROUND

Guttate psoriasis has a well-known association with streptococcal throat infections but the effects of these infections in patients with chronic psoriasis remains to be evaluated in a prospective study.

OBJECTIVES

To determine whether streptococcal throat infections are more common in and can cause exacerbation in patients with chronic psoriasis.

METHODS

Two hundred and eight patients with chronic plaque psoriasis and 116 unrelated age-matched household controls were followed for 1 year. At recruitment all patients were examined, their disease severity scored and throat swabs taken. Patients and corresponding controls were then re-examined and tested for streptococcal colonization whenever they reported sore throat or exacerbation of their psoriasis during the study period.

RESULTS

The psoriasis patients reported sore throat significantly more often than controls (61 of 208 vs. three of 116, P < 0.0001), and beta-haemolytic streptococci of Lancefield groups A, C and G (M protein-positive streptococci) were more often cultured from the patients than the controls (19 of 208 vs. one of 116, P = 0.003). A significant exacerbation of psoriasis (P = 0.004) was observed only if streptococci were isolated and the patients were assessed 4 days or later after the onset of sore throat. No difference was observed between groups A, C or G streptococci in this respect.

CONCLUSIONS

This study confirms anecdotal and retrospective reports that streptococcal throat infections can cause exacerbation of chronic plaque psoriasis. It is concluded that psoriasis patients should be encouraged to report sore throat to their physician and that early treatment of streptococcal throat infections might be beneficial in psoriasis. A controlled trial for assessing potential benefits of tonsillectomy in patients with severe psoriasis should also be considered.

Campylobacter spp. in Icelandic poultry operations and human disease

We describe the observed relationship of campylobacter in poultry operations to human cases in a closed environment. During 1999 in Iceland, domestic cases of campylobacteriosis reached peak levels at 116/100,000 and in 2000 dropped to 33/100,000. Approximately 62% of broiler carcass rinses were contaminated with Campylobacter spp. in 1999. During 2000, only 15% of the broiler flocks tested Campylobacter spp. positive. In 2000, carcasses from flocks which tested positive on the farms at 4 weeks of age were subsequently frozen prior to distribution. We suggest that public education, enhanced on-farm biological security measures, carcass freezing and other unidentified factors, such as variations in weather, contributed to the large reduction in poultry-borne campylobacteriosis. There is no immediate basis for assigning credit to any specific intervention. We continue to seek additional information to understand the decline in campylobacteriosis and to create a risk assessment model for Campylobacter spp. transmission through this well defined system.

Prevalence of resistance to ampicillin, gentamicin and vancomycin in Enterococcus faecalis and Enterococcus faecium isolates from clinical specimens and use of antimicrobials in five Nordic hospitals

We determined the species distribution and prevalence of ampicillin resistance, high-level gentamicin resistance (HLGR) and vancomycin resistance among clinical enterococcal isolates from five Nordic laboratories (Bergen, Tromsø, Uppsala, Aarhus and Reykjavik). Isolates represented three different groups: (i) all blood culture isolates from 1999; (ii) consecutive in-patient isolates (maximum 40); and (iii) consecutive outpatient isolates (maximum 40) collected during March to May 2000. Antimicrobial use data were collected at the national and hospital level. A high proportion (31.4%) of Enterococcus faecium was detected among blood culture isolates, in contrast to only 4.2% among isolates from outpatients. Ampicillin resistance was not found in Enterococcus faecalis, in contrast to 48.8% in E. faecium isolates. HLGR rates varied considerably between laboratories (1.1-27.6%). Acquired vancomycin resistance was not detected. There were no significant differences in the prevalences of HLGR between in-patient and outpatient isolates at individual hospitals. A cluster of clonally related ampicillin-resistant and HLGR E. faecium isolates was demonstrated in one of the hospitals. The lowest level of hospital antimicrobial use, the lowest proportion of E. faecium and the lowest prevalence of resistance were observed in Reykjavik. The study showed a relatively low level of resistance in enterococci, as compared with most European countries and the USA. However, there were large differences between hospitals with regard to the relative proportion of E. faecium isolates, their susceptibility to ampicillin and gentamicin, as well as the prevalence of HLGR in E. faecalis isolates. This indicates a potential for further improvement of antibiotic policies, and possibly hospital infection control, to maintain the low resistance levels observed in these countries.

Helicobacter pylori antibodies and gastric cancer in Iceland - The decline in IgG antibody level is a risk factor

H. pylori infection is considered a causal agent of duodenal ulcer and a significant risk factor for gastric cancer. Retrospective cohort studies have demonstrated a significant association between presence of antibody to H. pylori and gastric cancer when using samples obtained years before the diagnosis but not at the time of diagnosis. The present study investigates, in a population-based cohort, whether a decline occurs in H. pylori antibody levels before the diagnosis of stomach cancer. Repeat samples (2 to 5) were available from 23 persons with gastric cancer taken up to 20 years before the diagnosis and 128 control subjects matched for gender, age, time and number of repeat samples. The odds ratio of developing stomach cancer was 1.16 (95% CI 1.05-1.28) for those showing decline in antibody levels of 1 relative antibody activity unit per year versus those with constant or rising levels. We conclude that this decline in antibody levels in cases, and not in controls, supports an active role of H. pylori in the pathogenesis of gastric cancer by causing atrophic gastritis, and provides a better risk assessment for gastric cancer compared to single measurements.

Mathematical models as tools for evaluating the effectiveness of interventions: a comment on Levin

Possible interventions to minimize resistance rates are numerous and can involve reduction and/or change in antimicrobial use, infection control, and vaccinations. As mathematical models are becoming more realistic they can be useful to quantitatively evaluate the relative contribution of individual risk factors and for the planning of future intervention strategies. The fitness cost associated with resistance is an important parameter and small differences can have a profound effect on the results. The mathematical models presented for communities predicted that even with cessation of antibiotic use, the decline in resistance frequency would be slow. This contrasts with successful interventions in Finland and Iceland. Future models have to include important variables such as herd immunity and take into account the heterogeneity of open communities. Provision of susceptible strains from areas with low resistance rates to areas with high resistance rates can have a profound effect on the success of interventions to minimize resistance.

Penicillin pharmacodynamics in four experimental pneumococcal infection models

Clinical and animal studies indicate that with optimal dosing, penicillin may still be effective against penicillin-nonsusceptible pneumococci (PNSP). The present study examined whether the same strains of penicillin-susceptible pneumococci (PSP) and PNSP differed in their pharmacodynamic responses to penicillin by using comparable penicillin dosing regimens in four animal models: peritonitis, pneumonia, and thigh infection in mice and tissue cage infection in rabbits. Two multidrug-resistant isolates of Streptococcus pneumoniae type 6B were used, one for which the penicillin MIC was 0.016 microg/ml and the other for which the penicillin MIC was 1.0 microg/ml. Two additional strains of PNSP were studied in the rabbit. The animals were treated with five different penicillin regimens resulting in different maximum concentrations of drugs in serum (C(max)s) and times that the concentrations were greater than the MIC (T(>MIC)s). The endpoints were bacterial viability counts after 6 h of treatment in the mice and 24 h of treatment in the rabbits. Similar pharmacodynamic effects were observed in all models. In the mouse models bactericidal activity depended on the T(>MIC) and to a lesser extent on the Cmax/MIC and the generation time but not on the area under the concentration-time curve (AUC)/MIC. Maximal bactericidal activities were similar for both PSP and PNSP, being the highest in the peritoneum and blood (approximately 6 log10 CFU/ml), followed by the thigh (approximately 3 log10 CFU/thigh), and being the lowest in the lung (approximately 1 log10 CFU/lung). In the rabbit model the maximal effect was approximately 6 log10 CFU/ml after 24 h. In the mouse models bactericidal activity became marked when T(>MIC) was > or =65% of the experimental time and C(max) was > or =15 times the MIC, and in the rabbit model bactericidal activity became marked when T(>MIC) was > or =35%, Cmax was > or =5 times the MIC, and the AUC at 24 h/MIC exceeded 25. By optimization of the Cmax/MIC ratio and T(>MIC), the MIC of penicillin for pneumococci can be used to guide therapy and maximize therapeutic efficacy in nonmeningeal infections caused by PNSP.

Genetic diversity and clonal patterns among antibiotic-susceptible and -resistant Streptococcus pneumoniae colonizing children: day care centers as autonomous epidemiological units

Characterization by antibiotype of the 1,096 Streptococcus pneumoniae recovered from 2,111 nasopharyngeal samples of children attending 16 day care centers (DCCs) in Lisbon, Portugal, and molecular typing of 413 drug-resistant pneumococci (DRPn) and 89 fully drug-susceptible pneumococci (DSPn) has allowed several conclusions. (i) There was an increase in the frequency of DRPn colonizing children in DCCs from 40% in 1996 to 45% in 1997 to 50% in 1998. (ii) Drug resistance spread by cross-transmission of DRPn clones. A few (8 out of 57) DRPn clones were repeatedly isolated from a large number of children in several DCCs and during each period of surveillance, suggesting the epidemic nature of these clones, which included lineages representing internationally spread S. pneumoniae clones. (iii) Dissemination of resistance determinants among pneumococci colonizing the nasopharynx occurred. Association of identical pulsed-field gel electrophoresis patterns with diverse antibiotypes among pneumococci colonizing children suggests that the high prevalence of DRPn involves not only cross-transmission of resistant strains but also dispersal of resistance genes through recombinational mechanisms. (iv) DCCs are autonomous epidemiological units. Among the 413 DRPn, 57 different lineages were detected; these lineages were dispersed among the 16 DCCs to produce unique microbiological profiles for each of the DCCs. Higher genetic diversity and less sharing of clonal types were observed among the DSPn.

Carriage of internationally spread clones of Streptococcus pneumoniae with unusual drug resistance patterns in children attending day care centers in Lisbon, Portugal

Over half (259/503) of drug-resistant (DR) pneumococci colonizing healthy children attending day care centers in Lisbon were identified by molecular typing methods as representatives of several internationally spread clones. These included the 2 penicillin-resistant pandemic Spanish/USA and French/Spanish clones (21% of all DR pneumococci) and 5 new lineages with unusual antibiotypes (accounting for an additional 30% of all DR pneumococci). The most characteristic feature of the latter group was the high frequency of resistance to macrolides and tetracycline and very low or no resistance to penicillin. These observations provide support for the notion that the nasopharyngeal flora of children in day care centers may be a global reservoir of worldwide prevalent strains of DR pneumococci.

Molecular evolution in a multidrug-resistant lineage of Streptococcus pneumoniae: emergence of strains belonging to the serotype 6B Icelandic clone that lost antibiotic resistance traits

Since their first detection in 1988, penicillin-resistant Streptococcus pneumoniae isolates have rapidly spread in Iceland to account for close to 20% of all pneumococcal disease in that country by 1993. The major component (70%) of the resistant pneumococci identified from 1989 to 1992 was the progeny of a single multidrug-resistant clone (Icelandic clone) with a homogeneous chromosomal macrorestriction profile and identical multilocus enzyme type expressing serotype 6B and resistance to penicillin, tetracycline, chloramphenicol, erythromycin, and trimethoprim-sulfamethoxazole. The rest of the non-penicillin-susceptible isolates included bacteria with serotype 6A and serogroups 19 and 23. The unique geographic and epidemiological setting and the availability of a complete collection of all non-penicillin-susceptible isolates of S. pneumoniae in Iceland prompted us to carry out a molecular epidemiological study to monitor the fate of the Icelandic clone between 1989 and 1996; in addition, we wished to extend the characterization to representative groups of all non-penicillin-susceptible serotype 6B pneumococci which showed variations in antibiotype and which were recovered in Iceland between late 1989 and the end of 1996. Also included in the study were non-penicillin-susceptible isolates of serogroup 23. Pulsed-field gel electrophoresis of SmaI-restricted chromosomal DNA and Southern hybridization with the lytA DNA probe and probes specific for antibiotic resistance genes were used to characterize pneumococcal isolates. The results show that (i) the Icelandic clone remained the predominant type among penicillin-resistant S. pneumoniae through 1996; (ii) the emergence of variants of the Icelandic clone which had lost one or more of the antibiotic resistance phenotypes and/or resistant genes, singly or in combination, was documented during the surveillance period; and (iii) isolates belonging to the internationally spread multidrug-resistant serotype 23F clone were present in the Icelandic collection since late 1989 but did not increase in number during the subsequent years.

Epidemiology of penicillin resistant pneumococci in Iceland

The prevalence of penicillin-resistant pneumococci (PRP) has been increasing, with the highest levels reported from countries with relatively unrestricted antimicrobial use. It has been low in northern Europe except Iceland, which is disconcerting as antimicrobial use in Iceland has been relatively restricted. This suggests that other factors may facilitate their spread. By studying their epidemiology and possible risk factors for carriage, we have attempted to explain their rapid spread in Iceland. The incidence of infections caused by PRP (as percentage of infections considered due to pneumococci) has increased from 0% in 1988 to 2.3% in 1989, 2.7% in 1990, 8.4% in 1991, 16.3% in 1992, and 19.8% in 1993. The infections have mainly affected 0- to 3-year-old children (71.4%), and the PRP belonged almost exclusively to serogroups 6, 19, and 23 (98.8%). Most were serotype 6B multiresistant (75%; resistant to penicillin (MIC = 1.0), cephalothin, erythromycin, clindamycin, tetracycline, chloramphenicol, fusidic acid, sulfonamides, and trimethoprim), and believed to belong to a single clone originating from Spain. The PRP have been prevalent in healthy children, 0-10% nasopharyngeal carriage, especially in day-care centers, with the highest prevalence in areas that had the highest antimicrobial consumption. Recent antimicrobial consumption, especially of trimethoprim-sulfa, appeared to increase PRP carriage. The rapid spread of PRP in Iceland may have been facilitated by high antimicrobial consumption in day-care centers (especially of trimethoprim-sulfa) which are attended by the majority of Icelandic children.

Effect of antimicrobial use and other risk factors on antimicrobial resistance in pneumococci

Penicillin-resistant and multi-resistant pneumococci have spread globally and reached high prevalence in many countries. Antimicrobial use is considered a major driving force for resistance, although the influence in the community has not been as clearly demonstrated. Other risk factors may be important, and only with a clear understanding of the risk factors can effective control measures be introduced. The main habitat of the pneumococcus is the nasopharynx of children. Carriage increases from birth and is maximal at pre-school age. Antimicrobial use in children is likely to have a significant influence on the susceptibility of pneumococci. Most studies looking for risk factors for resistance in pneumococci have identified antimicrobial use as a risk factor, especially the following aspects: ongoing, recent, repeated, frequent, and prophylactic antibiotic use. The effect of individual classes of antimicrobials has not been studied in detail but use of beta-lactam antibiotics and trimethoprim-sulpha has been associated with increased risk. Other risk factors are young age, nosocomial acquisition, prior hospitalization, and HIV infection. Day-care centers can facilitate the spread of resistant pneumococci and an Icelandic study showed that carriage of resistant pneumococci was associated with young age, domicile in an area with high antimicrobial consumption, recent antimicrobial use, frequent antimicrobial use, and use of trimethoprim-sulpha. The rapid increase of penicillin-resistant pneumococci in Iceland was met with propaganda against overuse of antimicrobials, which lead to reduction of antimicrobial use and subsequently a reduced incidence of penicillin-resistant pneumococci. This reduction may be related to reduced antimicrobial use. Reducing antimicrobial use should be considered important for programs aimed at reducing antimicrobial resistance.

Carriage of respiratory tract pathogens and molecular epidemiology of Streptococcus pneumoniae colonization in healthy children attending day care centers in Lisbon, Portugal

In an effort to establish the rate of carriage of antibiotic resistant respiratory pathogens in children attending urban day care centers (DCC) in Portugal, seven DCC in Lisbon were selected for determining the rate of nasopharyngeal colonization of children between the ages of 6 months to 6 years by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Of the 586 children studied between January and March 1996, 47% carried S. pneumoniae, 72% H. influenzae, and 54% M. catarrhalis. Twenty-four percent of the pneumococci had reduced susceptibility to penicillin, and most of these belonged to serogroups 19, 23, 14, and 6. An additional 19% were fully susceptible to penicillin but showed decreased susceptibility to other antimicrobials. These isolates expressed serogroups 6, 11, 14, 18, 19, and 34. The majority (96%) of M. catarrhalis and 20% of H. influenzae were penicillin resistant due to the production of beta-lactamases. Recent antimicrobial use was associated with carriage of penicillin non-susceptible pneumococci and beta-lactamase producing H. influenzae (p < 0.05). Individual DCC differed substantially from one another in their rates of carriage of antibiotic resistant H. influenzae and S. pneumoniae. Characterization of antibiotic resistant S. pneumoniae isolates by molecular fingerprinting techniques showed that each DCC had a unique microbiological profile, suggesting little, if any, exchange of the resistant microbial flora among them. An exception to this was the presence of isolates belonging to two internationally spread epidemic clones: the multiresistant Spanish/USA clone expressing serotype 23F, and the penicillin and sulfamethoxazole-trimethoprim resistant French/Spanish clone (serotype 14) which were detected in four and three DCC, respectively.

Urinary tract infections, antibiotic resistance and sales of antimicrobial drugs--an observational study of uncomplicated urinary tract infections in Icelandic women

OBJECTIVES

To analyse the antimicrobial susceptibility pattern of bacteria causing symptomatic but otherwise uncomplicated lower urinary tract infections (UTI) in primary health care and the sales of antimicrobial drugs.

SETTING

Primary health care in Akureyri District, Northern Iceland, with about 17400 inhabitants.

PATIENTS

A total of 516 episodes of symptomatic but otherwise uncomplicated lower UTI in women 10 to 69 years of age.

MAIN OUTCOME MEASURES

Number of verified UTI, bacterial species, antimicrobial susceptibility pattern, and total sales of antimicrobial drugs.

RESULTS

Escherichia coli was by far the most common cause of UTI (83%), followed by Staphylococcus saprophyticus (7%). Infections caused by E. coli resistant to ampicillin accounted for 36% of cases, with the corresponding figures for sulfafurazol being 37%, cephalothin 45%, trimethoprim 13% and mecillinam 14%. Only 1% of the strains were resistant to nitrofurantoin. The total use of antimicrobial drugs was 17.4 DDD/1000 inhabitants/day.

CONCLUSIONS

The resistance of bacteria causing uncomplicated UTI to common antimicrobials is high and must be taken into account when selecting treatment strategies. High consumption of antibiotics in the community indicates possible association.

The relationship between the volume of antimicrobial consumption in human communities and the frequency of resistance

The threat to human health posed by antibiotic resistance is of growing concern. Many commensal and pathogenic organisms have developed resistance to well established and newer antibiotics. The major selection pressure driving changes in the frequency of antibiotic resistance is the volume of drug use. However, establishing a quantitative relationship between the frequency of resistance and volume of drug use has proved difficult. Using population genetic methods and epidemiological observations, we report an analysis of the influence of the selective pressure imposed by the volume of drug use on temporal changes in resistance. Analytical expressions are derived to delineate key relationships between resistance and drug consumption. The analyses indicate that the time scale for emergence of resistance under a constant selective pressure is typically much shorter than the decay time after cessation or decline in the volume of drug use and that significant reductions in resistance require equally significant reductions in drug consumption. These results highlight the need for early intervention once resistance is detected.

Pneumonia caused by penicillin-non-susceptible and penicillin-susceptible pneumococci in adults: a case-control study

The objective of this study was to investigate the observation that patients with pneumonia due to penicillin-non-susceptible pneumococci (PNSP) in many instances present with milder disease than patients with pneumonia caused by penicillin-susceptible pneumococci (PSP) and to compare the cost of treatment. The clinical data, APACHE II score and laboratory features of hospitalized adults with pneumonia caused by PNSP or PSP were compared, along with antibiotic and hospital costs. Each patient with PNSP pneumonia (n = 36) was matched to a control with PSP pneumonia of the same age and gender. There was no difference in smoking history, but PNSP pneumonia patients had received prior antibiotics more frequently (p < 0.007). The mean APACHE II score was not different, but when broken down into acute vs. chronic scores those with PSP pneumonia had a significantly higher acute score (p = 0.005). Bacteraemia was present in 9 of 31 (29%) patients with PSP compared to 2 of 25 (8%) with the PNSP pneumonia (p = 0.09). The majority of isolates in the PNSP group were of serotype 6B (minimum inhibitory concentration range 0.125-2.0 mg/l), whereas serotypes 7, 9, 14, 18 and 19 were noted among the 9 PSP isolates. Compared with the control group, patients with the PNSP strains had a significantly longer hospital stay, 26.8 vs. 11.5 days (p = 0.001) and higher average antibiotic cost, $736 vs. $213 (p < 0.0001). In conclusion, pneumonia in adults caused by PNSP is associated with a milder clinical presentation than infection caused by PSP, suggesting either that resistance carries a price or that the serotypes of PNSP are less virulent. Pneumonia due to PNSP resulted in increased cost because of prolonged hospitalization and the use of more expensive antibiotics.

Isotypes and opsonophagocytosis of pneumococcus type 6B antibodies elicited in infants and adults by an experimental pneumococcus type 6B-tetanus toxoid vaccine

Streptococcus pneumoniae is a major respiratory pathogen of infants, children, and the elderly. Polysaccharide vaccines have been useful in adult populations but do not elicit protective immunity in infants and young children. To enhance their immunogenicity, vaccines of pneumococcal polysaccharides conjugated to proteins are being developed. In this study antibody levels and opsonic activities were compared in sera of infants and adults injected with pneumococcal polysaccharide type 6B (Pn6B) conjugated to tetanus toxoid (TT) (Pn6B-TT). Healthy infants were injected with Pn6B-TT; group A was injected at 3, 4, and 6 months of age, and group B was injected at 7 and 9 months of age. A booster injection was given at 18 months. Adults were injected once. Antibodies were measured by enzyme-linked immunosorbent assay and radioimmunoassay, and their functional activities were measured by opsonophagocytosis of radiolabelled pneumococci. In adults, increases in immunoglobulin M (IgM), IgG, IgA, IgG1, and IgG2 to Pn6B were observed. Infants reached adult levels of IgG1 anti-Pn6B after the primary injections. After the booster injection the infant groups had total IgG- and IgM-Pn6B antibody levels similar to those of adults. After the booster injection, IgG1 was the dominant infant anti-Pn6B isotype and at a level higher than in vaccinated adults, but IgA and IgG2 antibodies remained at very low levels. Opsonic activity increased significantly after Pn6B-TT injections; the highest infant sera showed opsonic activity comparable to that of vaccinated adults. Overall, opsonic activity correlated best with total and IgG anti-Pn6B antibodies (r = 0.741, r = 0.653, respectively; n = 35) and was highest in sera with high levels of all Pn6B antibody isotypes. The results indicate the protective potential of a pneumococcal 6B polysaccharide protein conjugate vaccine for young infants.

Acute bronchitis in adults. How close do we come to its aetiology in general practice?

OBJECTIVE

To investigate how close we can come to the aetiology of acute bronchitis in adults in a primary care setting.

DESIGN

Prospective study.

SETTING

General practice population in Gardabaer district, south-western Iceland.

SUBJECTS

140 patients > or = 16 years old who were diagnosed as having acute bronchitis during a two-year period (1992-1993).

MAIN OUTCOME MEASURES

Laboratory investigations (twice with a minimum four-week interval), used in general practice to analyse respiratory tract infections. They included serology for Chlamydia pneumoniae, Mycoplasma pneumoniae, respiratory tract viruses, and the level of C-reactive protein.

RESULTS

Of a total of 140 patients, two blood samples were taken on scheduled time in 113 patients. Serology confirmed recent infection in 18 (16%) of these patients. Only two (2%) had a bacterial infection (one C. pneumoniae, one M. pneumoniae). The others (84%) did not have a significant increase in antibody titres. Only four (4%) had C-reactive protein levels higher than 48 mg/l.

CONCLUSIONS

The study indicates that it is difficult to come close to a precise aetiology with respect to infectious agents of acute bronchitis in general practice. We conclude that the disease is rarely caused by atypical bacteria such as C. pneumoniae and M. pneumoniae, and rarely caused by bacterial infections severe enough significantly to increase the level of C-reactive protein.

Immune responses of infants vaccinated with serotype 6B pneumococcal polysaccharide conjugated with tetanus toxoid

BACKGROUND

Streptococcus pneumoniae is a major cause of meningitis, bacteremia, pneumonia and otitis media. Pneumococcal polysaccharides are not immunogenic in infants, but improved immunogenicity of polysaccharide-protein conjugates has been demonstrated. Antibiotic-resistant pneumococci have increased the need for an effective vaccine.

OBJECTIVE

To study the safety and immunogenicity of a pneumococcal type 6B polysaccharidetetanus toxoid conjugate (Pn6B-TT) in infants and to assess the function of antibodies.

METHODS

Healthy infants were injected, Group A at 3, 4 and 6 months (n = 21) and Group B at 7 and 9 months (n = 19). Booster injection was given at 18 months. Antibodies were measured by enzyme-linked immunosorbent assay and radioimmunoassay, and functional activity was measured by opsonization of radiolabeled pneumococci. Nasopharyngeal cultures were obtained.

RESULTS

No significant adverse reactions were observed. Pn6B-IgG (enzyme-linked immunosorbent assay) increased to a geometric mean of 0.62 microgram/ml (P = 0.367, compared with prevaccination titers) in Group A at 7 months and 1.22 micrograms/ml (P < 0.001) in Group B at 10 months. Total Pn6B antibodies (radioimmunoassay) were 44 ng of antibody N/ml (P < 0.053) in Group A and 211 ng of antibody N/ml (P < 0.001) in Group B. A smaller increase in IgM and IgA anti-Pn6B was observed. Reinjection at 18 months elicited booster responses in total and IgG anti-Pn6B; 62% of those in Group A and 79% of those in Group B had > 300 ng of antibody N/ml. Opsonic activity, after initial and booster vaccinations, correlated with Pn6B-antibody titers. Three infants with nasopharyngeal cultures repeatedly positive for serogroup 6 had poor serum IgG responses.

CONCLUSION

Our results demonstrate that Pn6B-TT is safe, elicits functional antibodies and memory responses in infants.

[Ampicillin resistant enterococci at Landspítalinn University Hospital and antimicrobial susceptibilities of enterococci in Iceland.]

Hospital acquired infections caused by enterococci are an increasing problem, due to an increased number of infections and increasing bacterial resistance to antibiotics. During 1994 ampicillin resistant enterococci were discovered in specimens from three patients in one ward over a short time period. The patients were isolated and stool cultures were taken from everyone in the ward for selective culture for enterococci and subsequent antimicrobial susceptibility tests. Additional screening cultures were taken from patients in the intensive care unit, the oncology ward, one surgical and one paediatric ward. Cultures were also taken from the hospital sewage system. Antibiotic susceptibility of enterococci isolated from urine samples submitted to the Microbiology Department, Landspitalinn, during 1994 and 1995 were reviewed. In the index ward, specimens were obtained from 30 individuals for culture. One additional patient and one staff member were found to be colonised with ampicillin resistant enterococci. In the other wards a total of 23 samples were taken from selected patients for culture, but none of these cultures yielded ampicillin resistant enterococci. No ampicillin resistant enterococci were found in the sewage system of the hospital. Of a total of 41,181 urine specimens cultured at the Microbiology Department, 1,513 contained enterococci of which five were resistant to ampicillin (0.3%, all from 1994). We conclude that ampicillin resistant enterococci have not become established at Landspitalinn. It may be difficult to maintain a susceptible enterococcal population, however isolation of carriers and sensible use of broad spectrum antibiotics are likely to delay the establishment of multiresistant enterococci in Iceland.

Seroprevalence of Helicobacter pylori in south Sweden and Iceland

BACKGROUND

Seroepidemiologic studies on the prevalence of Helicobacter pylori infection have been reported from several European countries but not from Sweden or Iceland.

METHODS

Serum samples were collected from 443 persons in Sweden and 387 persons in Iceland. All the 830 sera were tested with the same enzyme immunoassay test with an acid glycine extract of H. pylori surface proteins as antigen.

RESULTS

The antibody levels were low in the young age groups in both Sweden and Iceland, with increasing levels with age.

CONCLUSIONS

The results are consistent with previous studies from other comparable countries, but with important differences. The prevalence was lower in Sweden than in other, previously studied, Western European countries, but, on the other hand, the prevalence was slightly higher in Iceland.

Do antimicrobials increase the carriage rate of penicillin resistant pneumococci in children? Cross sectional prevalence study

OBJECTIVE

To study the correlation of antimicrobial consumption with the carriage rate of penicillin resistant and multiresistant pneumococci in children.

DESIGN

Cross sectional and analytical prevalence study.

SETTING

Five different communities in Iceland.

MAIN OUTCOME MEASURE

Prevalence of nasopharyngeal carriage of penicillin resistant pneumococci in children aged under 7 years in relation to antibiotic use as determined by information from parents, patient's records, and total sales of antimicrobials from local pharmacies in four study areas.

RESULTS

Total antimicrobial sales for children (6223 prescriptions) among the four areas for which data were available ranged from 9.6 to 23.2 defined daily doses per 1000 children daily (1.1 to 2.6 courses yearly per child). Children under 2 consumed twice as much as 2-6 year olds (20.5 v 10.9 defined daily doses per 1000 children daily). Nasopharyngeal specimens were obtained from 919 children, representing 15-38% of the peer population groups in the different areas. Pneumococci were carried by 484 (52.7%) of the children, 47 (9.7%) of the isolates being resistant to penicillin or multiresistant. By multivariate analysis age (< 2 years), area (highest antimicrobial consumption), and individual use of antimicrobials significantly influenced the odds of carrying penicillin resistant pneumococci. By univariate analysis, recent antimicrobial use (two to seven weeks) and use of co-trimoxazole were also significantly associated with carriage of penicillin resistant pneumococci.

CONCLUSIONS

Antimicrobial use, with regard to both individual use and total antimicrobial consumption in the community, is strongly associated with nasopharyngeal carriage of penicillin resistant pneumococci in children. Control measures to reduce the prevalence of penicillin resistant pneumococci should include reducing the use of antimicrobials in community health care.

[The prevalence of H. pylori antibodies in Iceland.]

Helicobacter pylori causes gastritis and duodenal ulcerations, and is possibly one of the causes of gastric cancer. Diagnosis has relied on gastroscopy, but with the advent of reliable serological tests, epidemiological studies have become easier. Previous studies have indicated a higher H. pylori infection rate in Iceland than neighbouring countries. To study this further, an H. pylori (acid glycine extract) ELISA test was set up. Serum samples were obtained from 387 individuals, aged three months to 97 years, mean 41 years (161 blood donors, 83 outpatients, 64 ante natal clinic, 33 hospitalised children, 27 old people's home and 19 college students). Positive antibody titers were found in 151 (39%), of which 14 were borderline. The prevalence increased with age and was highest 75% in 60-69 years old, but lowest 9% in the youngest age group. The prevalence of H. pylori antibodies appears to be higher than in neighbouring countries, but lower than in the developing countries, and Icelanders appear to acquire the infection at a younger age than in the neighbouring countries. This high prevalence is important in view of the high prevalence of gastric cancer in Iceland.

[Peritonitis associated with peritoneal dialysis.]

Continuous ambulatory peritoneal dialysis (CAPD) is now a recognised treatment for end stage renal disease. An estimated number of 27.000 patients was being treated by CAPD world-wide in the year 1985. The most important complication is infection, peritonitis. The CAPD program started in Iceland in April 1985 at the dialysis department of the National University Hospital. The aim of this study was to estimate the incidence of infection associated with peritoneal dialysis during the first five years. All positive cultures of peritoneal dialysates from the Department of Bacteriology, and the hospital records of patients on CAPD, during the time period 12.04.1985 to 12.04.1990, were studied retrospectively. CAPD was considered started as soon as the peritoneal catheter had been inserted. Peritonitis was considered to be present when the white blood cell count was > 100/ul or there were clinical signs of infection together with a positive culture from the dialysate. During the study period 27 patients were treated by CAPD for 609.6 treatment months. Peritonitis was diagnosed 83 times in 18 of these patients, giving an incidence of 1.63/treatment year. The most common cause was Staphylococcus aureus, which was isolated 35 times (42%). Other causative organisms were: 17 coagulase negative staphylococci (21%), three Gram negative rods (4%), one yeasts and three mixed cultures. In 12 (14%) of the peritonitis episodes, no organisms were isolated. Admission to hospital was considered necessary in 74% of the episodes. One patient died of peritonitis. Studies have demonstrated various infection rates (0.23-6.3 infections/year), but has usually been between 0.8 and 1.2 infections/year. It is of interest to note that the most common causative organism in this study was S. aureus, as opposed to coagulase negative staphylococci, that have normally been the most prevalent. S. aureus usually causes tunnel infections, that are difficult to clear, without removing the catheter. This study demonstrates an above average prevalence of infection, which should prompt a reevaluation of the current management protocols.

[Nosocomial infections in the Intensive Care Unit at Landspitalinn.]

OBJECTIVE

To determine the nosocomial infection rate, pathogens, colonisation and hospital mortality in the Intensive Care Unit (ICU) at Landspitalinn, which is a ten bed, general medical-surgical ICU.

METHODS

Patients admitted for more than 48 hours were included. Surveillance- cultures were performed on admission and thereafter three times a week (tracheal aspirate, oropharyngeal swab, gastric aspirate, urine and other specimens as indicated). ICU infections were defined by the criteria of CDC, USA. In the first 12 months 140 patients met the inclusion criteria at 150 admissions. The study is ongoing.

RESULTS

Eighty-seven ICU-acquired infections were diagnosed in 48 of the 150 admissions (32%), the mean age was 58 years (0-87) and 60% were males. The most common infections were: UTI 27 (31%), pneumonia 18 (21%), septicemia 15 (17%), wound infections eight (9%) and tracheitis seven (8%). Etiologic agents of the 87 infections were E. coli (15), Klebsiella sp. (7) and other Enterobacteriacae (9), Enterococcus sp. (12), Candida sp. (12), S. epidermidis (7), P. aeruginosa (7) and other/unknown pathogens (18). Infected patients stayed for a mean of 15.0 days and uninfected patients 4.2 days (p<0.05). Every patient staying for more than three weeks had at least one infection. The mean age of infected patients was 63 years and of uninfected patients 56 years (p<0.05). Neither APACHE-II nor TISS score on admission differed significantly between the infected and uninfected groups. Mortality in the ICU was 10.4% (5/48) in the infected group and 19.6% (20/102) in the uninfected group (p=0.24).

CONCLUSION

Nosocomial infections in patients admitted to the ICU were common and associated with extended stay. Most of the infections were caused by Gram-negative bacilli.

[Epidemiology of penicillin resistant pneumococci.]

Penicillin resistant and multiresistant pneumococci have become common all over the world. Pneumococci resistant to cefotaxime and ceftriaxone have only become established in the USA, Spain and South Africa, although recently such strains have been described in the UK. Resistance to cefotaxime and ceftriaxone may spread faster than penicillin resistance. With B-lactam resistant and multiresistant pneumococci, the choice of antimicrobials is reduced to a single class of antimicrobials, the glycopeptides. Penicillin resistant pneumococci were introduced in Iceland in 1988, and had gained 20% incidence in pneumococcal infections in 1993. This rapid spread was associated with serogroups 6, 19 and 23, of which serotype 6B (multiresistant) was by far the most prevalent. During this period the incidence of penicillin resistant pneumococci remained low in the other Nordic countries. Since the practice of medicine is very similar in these countries, it was important to search for epidemiological clues that would explain the difference. The following risk factors have been shown to be important in epidemiological studies conducted in Iceland: most Icelandic children attend day-care centres, where they have numerous contacts with children with respiratory tract infections during the long winter months. Antimicrobial usage was high in children attending day care centres. The popularity of the sulpha-trimethoprim combination in Iceland may also be important, as it was shown to be an independent risk factor. Total use of antimicrobial agents declined in Iceland in the years 1991-1993 following a propaganda campaign against misuse and legislative changes that increased the cost of the antimicrobials for patients. The antimicrobial use in day-care centres was significantly reduced from 1992 to 1995. In 1994 the incidence of penicillin resistant pneumococci decreased to 17% (from 20% in 1993). Hopefully reduction in antimicrobial use will continue and contribute to further lowering of resistance levels.

[Antibiotic use and misuse at the National University Hospital, Iceland.]

INTRODUCTION

Antibiotics are responsible for 20-25% of the total drug-cost in the larger hospitals in Iceland. Studies from other countries, both in Europe and North-America suggest that 40-70% of both antibiotic therapy and prophylaxis is inappropriate in the larger teaching hospitals. We undertook a prospective study to determine the patterns of antimicrobial use in a university hospital.

METHODS

Data on antibiotic prescriptions were collected over two four week periods in April and August 1994 on 12 wards at the National University Hospital.

RESULTS

During the eight weeks 302 (30%) of 1020 hospitalized medical, surgical and gynecological patients received one or more courses of antimicrobial therapy. Presumptive infection was the reason for therapy in 73% of the cases, prophylaxis in 35% and both therapy and prophylaxis in 8%. Cephalosporins were the most commonly used drugs for antimicrobial therapy and cloxacillin for prophylaxis. Therapy was judged appropriate in only 45% of the courses. Poor drug choice (bacterologically, pharmacologically), misguided prophylaxis, wrong drug dosage or unneccessary therapy were the most frequent reason for inappropriate therapy.

CONCLUSION

Because of the worldwide increase of antibiotic-resistant strains the results of this study clearly indicate the need for additional measures to improve antibiotic use.

[Results of cultures and serotyping of S. pyogenes 1986-1993.]

Streptococcus pyogenes is a major human pathogen. It is a common cause of pharyngitis, cellulitis and wound infections. Late complications like rheumatoid arthritis and glomerulonephritis are associated with certain M proteins on the surface of the bacteria. In 1987 an increase was noted in the incidence of serious infections caused by this bacterium. The increase has been associated with protein type M 1. Typing with antibodies against T proteins is simpler to perform than M typing and can give as good epidemiological information. Culture results from January 11986 to December 31 1993, from the Department of Microbiology at the National University Hospital in Reykjavik, were reviewed. T protein type of some of the strains, that had been preserved by freezing, was determined by agglutination after culture in Todd Hewitt broth as described by Efstratiou. T-protein type of 384 strains from 1991-1993 was determined and the results compared to unpublished results from 1988 and 1989. T-protein type was also determined on all S. pyogenes strains that were isolated from blood in 1989 to 1993. The following T-types were most common: 1988-1989 Tl vas 30%; 1991, T4 and T28 70% and 62% in 1992; in 1993 Tl and T3 were 59%. Thirty one strains were sent to the Streptococcal Reference Laboratory, Central Public Health Laboratory, London, for determination of M-proteins. All strains but one, that were sent to Britain for M-protein typing, had corresponding T-proteins (Mx=Tx; My=Ty and so on). Big fluctuations in the number of isolations of S. pyogenes strains was observed during the study period: Fewest in 1989 or 629, but the number was highest in 1993 or 2057. The changes in incidence seemed to correlate with certain serotypes.

[Human listeriosis diagnosed in Iceland 1978-1994.]

Listeriosis has been recognised in Iceland, as a distinct disease entity in sheep called silage disease (votheysveiki), since 1910. The use of silage was introduced in Iceland in the latter part of the 19th century. Because of the climatic conditions it came into widespread use and the connection between silage and listeriosis was first demonstrated in Iceland by Pálsson et al. The first case of human listeriosis was diagnosed in 1961. The diease was not diagnosed again untill 1978 when four cases were identified. In the period between 1978 and 1994 L. monocytogenes was isolated from 36 patients, 11 males and 25 females. During this period the population of Iceland grew from 224.384 to 264.919. If mother and child are counted as one the incidence is approximately 8.3 per million per year. There were nine cases of neonatal infections, nine cases involving pregnant women, 13 cases of immunosuppressed patients and five patients were previously healthy. There were four miscarriages. The patients received conventional treatment of ampicillin and aminoglycoside or in one case chloramphenicol. All neonates but two survived. One older patient with meningitis died and 3 severely immunocompromised patients died. All of the strains were of the most common serotypes, 4b, l/2a and l/2b. The different serotypes were not evenly distributed during the study period. During the years 1978-1984 only one of 13 isolates was serotype l/2a and the rest was 4b. On the other hand all but three strains isolated since 1985 were either 172a or l/2b. During the first part of the study period the majority of cases involved neonates or pregnant women but during the second part most of the patients were old or immunocompromised. Nothing is known about the source of the infection in any of the patients except in one neonate which was considered to be nosocomially infected.

[Prevalence of genital chlamydia trachomatis infections in college students.]

Sexually transmitted Chlamydia infection is the most common venereal disease in Iceland. Although considerable information is available on the epidemiology of these infections, the true prevalence of C. trachomatis infections in Iceland is unknown because all the studies have been conducted on selected populations. The purpose of the present study was twofold: To investigate the prevalence of Chlamydia infection in an unselected group of people in the age group at high risk, and to investigate the usefulness of collecting urine samples from college students as a screening method for Chlamydia. All students, aged 18-21, in the senior classes in a college in Reykjavik were requested to submit a first void urine (FVU) specimen taken in the morning and asked to fill out a short questionnaire. The urine samples were tested with a polymerase chain reaction assay, the Amplicor(R) PCR. One hundred eighty three students received urine collection kits. One hundred sixty (87.4%) delivered specimens. Seventy three males and 110 females received the containers. Sixty males (82%) and 100 (91%) females returned the samples. Three samples turned out to be positive (2%), all of them from females. For those who were sexually active (one or more partners for the last six months) the prevalence was 2.6% (117/160).

IN CONCLUSION

The prevalence of asymptomatic Chlamydia infection in college students in this school was low, probably too low for screening to be cost effective. The procedure was not satisfactory because of the low percentage that enquired about their tests. It is therefore unsuitable in a screening program.

[Diagnostic efforts for the detection of chlamydia trachomatis infections in Iceland 1982-1994.]

The results of diagnostic testing for the detection of Chlamydial infections in Iceland during the years 1982 to 1994 were reviewed. During those 13 years 123,461 laboratory tests were performed in 101,574 examinations. These examinations were positive in 14,462 instances. The first diagnostic test to be introduced was cell culture in 1982. From then on the number of examinations and the number of positive examinations increased steadily until 1988, when positive examinations reached a peak at approximately 570 cases per 100,000 inhabitants. In 1990 a sharp decline in both the total number of examinations and positive results was observed. The percentage of positive examinations declined during the study period. In 1991 and 1992 the number of examinations, the number of positive examinations and the percentage of positive examinations increased but the number of positive tests declined again in 1993. In 1994 the polymerase chain reaction assay (PCR) replaced the much less sensitive Chlamydiazyme(R) assay and the number of positive examinations rose again although the number of tests declined. The dramatic reduction in prevalence experienced in Sweden does not seem to have taken place in Iceland. In Sweden a substantial effort was made to screen asymptomatic populations. In Iceland the screening of asymptomatic patients increased from the beginning of the study period until 1988 but declined thereafter. Screening of asymptomatic populations as well as contact tracing may be important for bringing about a significant reduction of the prevalence of sexually transmitted infections caused by Chlamydia trachomatis.

Evidence for the introduction of a multiresistant clone of serotype 6B Streptococcus pneumoniae from Spain to Iceland in the late 1980s

Almost all of the multiresistant pneumococci that appeared suddenly in clinical specimens in Iceland between 1989 and 1992 belonged to serogroup 6. Fifty-seven of these isolates were analyzed for serotype, penicillin-binding protein pattern, multilocus enzyme genotype, and fragmentation pattern obtained by pulsed-field electrophoretic separation of restriction enzyme digests of chromosomal DNA. All isolates were of serotype 6B and had similar or identical patterns in each molecular test. The Icelandic isolates were indistinguishable from a subgroup of multiresistant serotype 6B pneumococci that has been present with high incidence in Spain during the past two decades. The data suggest the import to Iceland of a single multiresistant clone of pneumococcus, most likely from Spain.

Native-valve endocarditis due to Neisseria sicca: case report and review

Many species of the Neisseria, gram-negative diplococci that are frequent respiratory commensals in humans, have been regarded as being nonpathogenic or as causing disease in only immunocompromised hosts; in contrast, gram-negative diplococci such as Neisseria meningitidis and Neisseria gonorrhoeae are known pathogens. We report a case in which Neisseria sicca was the cause of serious infection (with catastrophic consequences) in an immunocompetent patient and review the world literature on endocarditis due to N. sicca.

In-vitro efficacy of a central venous catheter complexed with iodine to prevent bacterial colonization

Infections of central venous lines are still a problem in daily medicine. Despite adequate antibiotic therapy, removal of an infected catheter often becomes necessary. A simple procedure has been developed by which a special hydrophilic central venous catheter (Secalon-Hydrocath) can be loaded with iodine. Iodine is complexed in the hydrophilic polyvinylpyrrolidone surface coating of the Hydrocath catheter and is released during contact with an aqueous medium. The amount of complexed iodine depends on the incubation time in Lugol's solution. Antimicrobial activity of the loaded catheters was assessed with Staphylococcus epidermidis, showing complete inhibition of bacterial adherence to the catheters for the duration of iodine release. Depending on the experimental conditions, iodine released from the catheter is also active on bacteria in the surrounding medium.