Outbreak of methicillin-resistant Staphylococcus aureus in two nursing homes in Central Norway.

Until recently, infections with methicillin-resistant Staphylococcus aureus (MRSA) have mainly been associated with hospital outbreaks in Norway. However, increasingly cases are contracted outside hospitals. This paper reports the first two outbreaks of MRSA in two nursing homes in central Norway, affecting 23 residents and five staff members. Pulsed-field gel electrophoresis analysis showed that all strains from nursing home A were identical and that the strains from nursing home B were genotypically similar with one or two band differences. Multi-locus sequence typing (MLST) showed that the strains from the two nursing homes belong to clonal complex 45, with each strain being a single-locus variant of sequence type 45 (ST 45), a well-known European epidemic strain. No evident source of the two outbreaks was found, and there was no obvious connection between the two outbreaks. The latter is also supported by the minor differences observed by MLST, suggesting a connection at some time in the past. The outbreaks led to a heavier workload and economic strain on both nursing homes. The outbreak in nursing home A was brought to an end, whereas two residents remained colonized in nursing home B despite several eradication attempts. These outbreaks show the potential for MRSA spread in a nursing home. If the prevalence of MRSA in Norway continues to increase, nursing home staff and residents may have to be included in the groups to be screened for MRSA upon hospital admission.

A K+ channel is involved in LPS signaling.

We previously showed a clear correlation between the molecular conformation of the lipid A moiety of endotoxin molecules and their cytokine-inducing capacity in mononuclear cells. While conically shaped lipid A moieties exhibit a high agonistic activity, a shift to a more cylindrically shaped lipid A leads to a decrease in agonistic and increase in antagonistic activity of the endotoxin molecules. Here, we show the involvement of a high-conductance Ca2+-activated potassium (MaxiK) channel in LPS signaling in macrophages. Corresponding to their biological activity, endotoxins activate a MaxiK channel as shown in outside-out patch-clamp experiments. LPS antagonists and anti-CD14 antibodies inhibit the LPS-induced activation of the channel. Blocking of the channel by specific channel blockers in macrophage cultures leads to inhibition of cytokine mRNA production. In particular, this result implies that there is no other independent transmembrane signaling pathway operative in macrophages. A shift of the molecular conformation of an a priori antagonistic lipid A from a cylindrical to a conical shape by adding the membrane-active compound chlorpromazine increases the activity of the MaxiK channel and the biological activity of the lipid A. We conclude that the activation of the MaxiK channel is a very early step in LPS-induced signaling in macrophages.

The role of membrane-bound LBP, endotoxin aggregates, and the MaxiK channel in LPS-induced cell activation.

We have previously shown in patch-clamp experiments on excised outside-out cytoplasmic membrane patches from human macrophages that the activation of a high-conductance Ca(2+)- and voltage-dependent potassium channel, the MaxiK channel, is an early step in LPS-induced transmembrane signal transduction in macrophages. MaxiK can be activated by agonistically active LPS, and activation can be completely inhibited by LPS antagonists (e.g. synthetic compound 406) and by anti-CD14 antibodies. Furthermore, by inhibiting MaxiK with the specific MaxiK blocker paxilline, we could show that activation of MaxiK is essential for LPS-induced cytokine production. As shown by RT-PCR, blockade of MaxiK by paxilline also inhibits induction of the mRNA of TNF-alpha and IL-6. This observation together with the fact that all patch-clamp experiments were done on excised outside-out patches reveal that MaxiK activation is an early step in cell activation by endotoxins. Thus, since cells lacking TLR4 on their surface can also not be activated to produce cytokines, these data allow the conclusion that TLR4 and MaxiK are both essential for activation by LPS and may form a co-operative signaling complex. We have also shown that LBP not only exists as a soluble acute-phase serum protein, but is also incorporated as a transmembrane protein (mLBP) in the cytoplasmic membrane of MNC; in this configuration, it is obviously involved in the binding of endotoxin and its transfer to the transmembrane signaling proteins finally triggering cell activation. Complexation of soluble LBP and LPS in the serum prior to binding of LPS to mLBP, in contrast, leads to neutralization of LPS. Here, we provide evidence from fluorescence resonance energy transfer spectroscopy that endotoxin aggregates are intercalated into reconstituted membranes by mLBP. In addition, cell culture assays and patch-clamp experiments demonstrate that endotoxin activates macrophages and the MaxiK channel in the aggregated, but not in the monomeric, state at similar concentrations.

Susceptibility pattern of Scandinavian Francisella tularensis isolates with regard to oral and parenteral antimicrobial agents.

Some recently introduced antimicrobial agents have only been incompletely evaluated for use in Francisella tularensis infections. The present study evaluated the susceptibility pattern of Scandinavian human, rodent, and hare F. tularensis isolates with respect to a selection of traditional as well as recently introduced antimicrobial agents. All strains were resistant to the following beta-lactams: penicillin, cephalexin, cefuroxime, ceftazidime, aztreonam, imipenem, and meropenem with minimal inhibitory concentrations > 32 mg/l. Against macrolides, a mixed susceptibility/resistance pattern appeared. All strains were susceptible to gentamicin, chloramphenicol, doxycycline, and four quinolones. Since the quinolones showed the lowest MIC values, and in addition give a good intracellular penetration, we conclude that future drugs to consider against tularemia should definitely include this group of antibiotics. The outpatient mode of antibiotic treatment is especially relevant as the Scandinavian variant of F. tularensis infection is nonlethal, usually pustuloglandular, and not septicemic. Therefore, oral drugs must be sought, and the quinolone group also satisfies this requirement.

Living with methicillin-resistant Staphylococcus aureus: a 7-year experience with endemic MRSA in a university hospital.

A review of our infection control records revealed 3,159 new isolations of methicillin-resistant Staphylococcus aureus (MRSA) from 1988 to 1994. Prior to this period, our approach to MRSA had changed from eradication to containment measures. We found a decline in MRSA rates from 11.4 to 5.2 first isolations per 1,000 deaths and discharges over the study period.

Field investigations of tularemia in Norway.

In Norway, tularemia is a common disease in small rodent and hare populations, where large outbreaks can be observed. In humans, the yearly number of cases is low, usually less than ten, with peaks up to 44 recorded in recent years. Serological investigations on hunters and healthy school children nevertheless indicate, with up to 4.7% positivity in the latter group, that Francisella tularensis low-grade infection is widespread. F. tularensis in co-culture with amoebae, e.g. Achantamoeba castellanii, may grow after internalization and kill the amoeba. As with Legionella, Francisella virulence may be enhanced after protozoan ingestion. This suggests a mechanism that can explain the pattern of dissemination and infection in our region.

National prevalence survey on hospital infections in Norway.

A nationwide prevalence survey was carried out in Norwegian hospitals (excluding mental hospitals) on 23 October 1997. The aim was to assess the magnitude of major hospital-acquired infections (HAIs) prior to the introduction of quarterly prevalence surveys in Norway as required by the new Regulations for Communicable Disease Control in Hospitals. The survey included 71 of 76 possible hospitals, and 12,775 patients. Altogether 779 HAIs were identified--a prevalence rate of 6.1%. Only the four major HAIs were included: urinary tract infection (36.4% of all HAIs); surgical wound infection (28.6%); lower respiratory tract infection (25.4%) and septicaemia (9.6%). Three thousand, three hundred and forty-nine patients had undergone surgery and the prevalence of surgical wound infection was 6.3%. The results form a baseline for the next step in Norweigan hospital infection control; the quarterly prevalence surveys.

Tularemia: a differential diagnosis in oto-rhino-laryngology.

Tularemia can present as an oto-rhino-laryngological disease. The clinical and radiological (CT) manifestations, diagnosis and treatment are discussed based on a case report where a patient with tonsillitis and enlarged cervical lymph nodes was admitted to the department of oto-rhino-laryngology of a hospital in Northern Norway. Francisella tularensis was isolated from the blood and there was a high titre of agglutinating serum antibodies to F. tularensis. The patient's contaminated drinking water well is the suspect source of infection.

[Bacteremia in the county of Ribe]. / Bakteriaemi i Ribe Amt.

The Department of Microbiology at the Central Hospital of Esbjerg, established in 1987, serves the five hospitals in Ribe county, Denmark. From early on, the department has endeavoured to guide the hospital's antimicrobial policy. In order to investigate whether this involvement had any measurable impact on the antimicrobial resistance pattern in our region, we compared the resistance patterns of 212 strains isolated from the blood of bacteraemic patients in 1988 to those of 317 strains isolated in 1992. No increase in antibiotic resistance was revealed. This is noteworthy since new specialties have been established at the Central Hospital during this period, with an increased number of patients requiring antimicrobial therapy. It is important to survey the antibiotic resistance pattern closely, and that this is done locally.

Resistant strains isolated from bacteremia patients in northern Norway.

Bacterial isolates from blood cultures in 1985 and 1989 (227 and 258 isolates, respectively), were compared as regards resistance to a series of antimicrobial agents including the more recent beta-lactams and quinolones. An increase in the number of coagulase-negative staphylococcal strains and a decrease in Staphylococcus aureus strains were detected, otherwise there were no significant differences in the bacterial patterns in 1985 compared to 1989. Except for chloramphenicol, there was no major increase in antimicrobial resistance among Gram-negative species. An increase in the number of multiresistant enterobacteriaceae strains was due to an increased number of klebsiella strains and a decrease in Proteus mirabilis. S. aureus showed an increased resistance to sulfonamides. No methicillin-resistant strain was found. Coagulase-negative staphylococci were significantly more often multiresistant in 1989 than in 1985, and significant increase in resistance to gentamicin, sulfonamides and fusidic acid was found.

Significance of immunoglobulin A titres in the diagnosis of urogenital chlamydial infections.

The significance of chlamydial serum IgA compared with IgM and IgG in the diagnosis of urogenital chlamydial infection was evaluated using 120 sera from different categories of patients. In urethritis patients both IgM and IgA antibodies were not found to be present consistently, whereas in patients with deep-seated chlamydial infection, IgA was more often present. Although of limited value in superficial infections, demonstration of IgA antibodies may be of value in the diagnosis of deep-seated chlamydial infections.

Epidemiological aspects of community-acquired and hospital-acquired bacteremia in northern Norway.

389 patients with 401 bacteremic episodes, either community-acquired (CAB) or hospital-acquired (HAB), admitted to the University Hospital of Tromsø (UHT), Norway, and 3 small local hospitals in the region (LHs), were reviewed on the basis of data collected in 1985 and 1989. As regards incidence, sex- and age distribution, distribution to either surgical, medical, or pediatric wards, compared with etiological agents and predisposing factors, the statistical significance has been evaluated. The proportion of patients < 50 years was greater at UHT than in the LHs. More patients with HAB associated with predisposing factors were hospitalized at UHT than at the LHs. Coagulase-negative staphylococci occurred less frequently in bacteremic patients at UHT than at the LHs. As opposed to reports from elsewhere, Tromsø University Hospital seems to appear much more similar to the smaller local hospitals in the epidemiological aspects of bacteremia, inasmuch as both HAB and the CAB presented an even distribution pattern between the 2 hospital groups.

Treatment of tularemia with ciprofloxacin.

A case of tularemia which occurred after close contact with a cat is presented. After unsuccessful amoxicillin treatment, a two-week course of doxycycline was given whereupon the patient responded well. However, the patient relapsed shortly after and was then given ciprofloxacin for two weeks. The patient then recovered completely. Clinical trials are needed in order to establish whether a quinolone could be the drug of choice for treatment of tularemia.

[Antibiotic resistance of blood culture isolates in Buskerud in 1994 and 1998]. / Antibiotikaresistens i blodkulturisolater i Buskerud i 1994 og 1998.

BACKGROUND: The increase of antimicrobial resistance has caused general concern world-wide. There is a high risk that this development will also occur in Norway. Several efforts have been made to prevent the emergence of antimicrobial resistance. A national surveillance programme for antimicrobial resistance has been started, and new legislation has made resistance surveillance programmes compulsory in every Norwegian hospital. Local surveillance of resistance is among the most important measures. MATERIAL AND METHODS: We have undertaken surveillance of all blood culture isolates from the County of Buskerud in 1994 and 1998. Detection of antibiotic resistance-patterns were undertaken for all blood culture isolates in the two years using disc diffusion method (Rosco diagnostics, Taastrup, Denmark). We also looked at the consumption of antimicrobial agents in Buskerud Central Hospital in 1998. A total of 628 isolates from 572 patients were included in the study, 279 isolates from 1994 and 349 from 1998. RESULTS: We still have low occurrence of resistance in Buskerud, and there has been no significant increase during the four-year period. INTERPRETATION: The low prevalence of antibiotic resistance reflects the restrictive antibiotic policy in Norway. Therefore, we find it important to continue this policy and to continue close surveillance of the development of antibiotic resistance.

[Bacterial endocarditis after treatment by a natural healer]. / Bakteriell endokarditt etter behandling hos naturmedisiner.

We describe a case of endocarditis caused by Propionibacterium acnes after a series of 'vitamin' injections and semipermanent acupuncture needle maneuvers by a natural healer. The patient had prosthetic heart valves. We found that the most probable source of infection was the treatment by the natural healer and therefore wish to warn against invasive treatment of such high-risk patients by laymen. If such treatment is insisted upon in spite of such warnings, antibiotic prophylaxis should be considered.

[Chlamydia pneumoniae--pathogenesis and perspectives]. / Chlamydia pneumoniae--patogenese og perspektiver.

Chlamydia pneumoniae, a Gram-negative bacterium, formerly named TWAR but identified as a distinct species since 1988, is now considered to be the most common agent of chlamydial infection in Scandinavia. C pneumoniae has a different tissue trophism from that of Chlamydia trachomatis, since C pneumoniae may infect bronchi and lungs, macrophages, monocytes, and endothelial cells. C pneumoniae, like other chlamydiae, has a slow, intracellular life cycle. An absence of reaction from the host cells, combined with scant tissual reaction owing to the low endotoxic activity of chlamydial lipopolysaccharide, may help to explain the usually discreet clinical picture. Atherosclerosis and coronary heart disease may follow chronic lung infection, and acute pneumonic episodes can trigger myocardial infarct. Asymptomatic infection with C pneumoniae is widespread. Intriguing diagnostic questions are the possible existence of a non-pathogenic carrier state, and the conceivable sensitization of the host with respect to a heterotypic, secondary chlamydial infection by, for example, C trachomatis, giving rise to an aggravated clinical picture. Early antibiotics are indicated to avoid the development of chronic disease.

Outbreak of methicillin-resistant Staphylococcus aureus in a Norwegian hospital.

Methicillin-resistant Staphylococcus aureus (MRSA) occurred sporadically in Norwegian hospitals in the 1960s and 1970s, but disappeared in the late 1970s for unknown reasons. Only 1 outbreak has subsequently been reported. We describe herein a second outbreak in a different hospital, this time featuring a more resistant strain. Staff and patients were screened immediately after detection of the first MRSA isolate. Colonized and infected patients were nursed using contact precautions, and the staff were not allowed to work until 3 nose samples were MRSA-negative. We treated colonized persons with topical administration of mupirocin to the nostrils and a chlorhexidine body wash. The outbreak affected 7 patients and 5 healthcare workers. Pulsed-field gel electrophoresis proved all isolates to be of the same type, and the MRSA phage type was M3. There was no sign of transmission of MRSA after contact precautions were implemented. MRSA was eradicated in 4 of the patients and all 5 healthcare workers. One patient died and 1 was still colonized 3 y after onset of the outbreak. Contact precautions proved to be sufficient to prevent transmission of MRSA.