National surveillance of Helicobacter pylori eradication therapy in Denmark. Results from registration of 34,582 prescriptions

BACKGROUND

We wanted to characterize the use of Helicobacter pylori eradication therapy in Denmark (5,227,862 inhabitants).

METHODS

All H. pylori eradication treatments from a nationwide database including all redeemed drug prescriptions in the period January 1994 to June 1996 were identified. So were all outpatients receiving a drug prescription for H. pylori eradication.

RESULTS

We recorded 34,582 prescriptions for H. pylori eradication therapy given to 28,784 patients. The incidence of new consumers was 220 per 10(5) inhabitants per year, with a maximum at 70-79 years of age. Eighty-six per cent of the patients had only one treatment course. In 16% of the eradication therapies, nonsteroid anti-inflammatory drugs had been prescribed within the previous 3 months, and 45% had an anti-ulcer drug prescribed 1-12 months after the H. pylori eradication therapy. Consumption of antibiotics used for H. pylori eradication accounted for 1.4% of the total consumption of antibiotics.

CONCLUSIONS

The incidence of H. pylori eradication therapy was fairly stable but with changes in the pattern of drug regimens used. Anti-ulcer drugs were often given after H. pylori eradication therapy, suggesting an inappropriate use of treatment.

[Extended spectrum beta-lactamases in Danish Klebsiella isolates]

This study presents the first two cases of infections with Klebsiella pneumoniae producing extended spectrum betalactamases (ESBL) that have been recorded in Denmark. They presented as a urinary tract infection and a generalized infection in a patient admitted to an intensive care unit. Both patients had been treated with broad spectrum antibiotics prior to infection. Presumably, one of the strains had been imported from Turkey. The ESBL of the two strains were characterized as SHV-2 and SHV-5, respectively. Patients transferred from hospitals abroad should be screened for Klebsiella producing ESBL, in addition to MRSA and other multiresistant organisms. A restrictive antibiotic policy and strict hygienic precautions are essential measures to control the selection and spread of such organisms in the hospital environment.

Epidemiology of Klebsiella bacteraemia: a case control study using Escherichia coli bacteraemia as control

Epidemiological data from 117 episodes of Klebsiella bacteraemia were compared with those from matched controls with Escherichia coli bacteraemia. Cases and controls were obtained from 20,631 blood cultures taken from patients in Hvidovre Hospital between 1990 and 1992. The data studied included: sex and age, risk factors, portal of entry, outcome, nosocomial acquisition and distribution within the hospital. The incidence of Klebsiella bacteraemia was 9.3/10,000 admissions (76% Klebsiella pneumoniae; 24% Klebsiella oxytoca). Patients with Klebsiella and E. coli bacteraemia had many common features, including a high incidence of neoplastic disease, biliary tract disease, and renal failure. Many had undergone surgery or received therapy with steroids, antacids or antibiotics. Klebsiella bacteraemia was more often found in males, in patients with hospital contact within the previous month, and polymicrobial infection. Logistic regression analysis showed that use of invasive plastic devices and diabetes were significantly associated with Klebsiella bacteraemia. The urinary tract was the commonest source, followed by the biliary tract; 27% of patients had no obvious focus of infection, and in many of these an invasive device may have been involved. Forty-five K-serotypes were found--the largest number being nine strains of type K3; only a few strains had acquired resistance characters to antimicrobial agents. There were no differences between community- and hospital-acquired strains; indicating that our hospital does not have a resident strain of Klebsiella.

Staphylococcus aureus bacteraemia among patients undergoing dialysis--focus on dialysis catheter-related cases

BACKGROUND

Central venous catheter-related infections are the most common cause of nosocomial S. aureus bacteraemia in Denmark. Central venous catheters are often used for dialysis, and patients on dialysis often run into staphylococcal infections. The purpose of this study was to investigate S. aureus bacteraemia among dialysis patients, especially those related to dialysis catheters.

METHODS

This was a retrospective study of 14,387 consecutive S. aureus bacteraemia cases during the period 1976-93, of which 793 cases occurred among dialysis patients. By reviewing the case records, 65 dialysis catheter-related cases were described more thoroughly.

RESULTS

The number of S. aureus bacteraemia cases among dialysis patients as a proportion of all cases in Denmark has increased from 5.2 to 14.7% during the study period, but the annual incidence among these patients has been almost stable during the period (median 5.7% (3.2-9.0%)). Patients on dialysis had a lower mortality than other patients with S. aureus bacteraemia (18.9 vs 29.0%), but a four times higher mortality from central venous catheter-related S. aureus bacteraemia (5.3 vs 1.3%, P < 0.001). The mortality from dialysis catheter-related S. aureus bacteraemia was correlated with greater age (median 71 years (57-73) vs median 56.5 years (15-76), P < 0.01) and with septic shock (55.5 vs 7.1%, P < 0.05). Patients on dialysis had a lower frequency of S. aureus endocarditis (3.3 vs 5.4%, P < 0.01) and of S. aureus bone and joint infections (3.3 vs 8.2%, P < 0.001) than other patients. Patients undergoing dialysis had a later onset of catheter-related S. aureus bacteraemia than other patients (median 15 days (1-145) vs 5 days (1-134), P < 0.05).

CONCLUSIONS

Patients on dialysis are at a high risk of S. aureus bacteraemia and they have a four times higher mortality from central venous catheter-related S. aureus bacteraemia than other patients. There is need for prospective studies in which patients as well as catheters are followed more thoroughly to study the pathogenesis of dialysis catheter-related infections.

Escherichia coli bacteraemia in patients with and without haematological malignancies: a study of strain characters and recurrent episodes

We compared serotypes, virulence factors and susceptibility to antibiotics of Escherichia coli strains isolated from 282 patients with bacteraemia. Thirty-five of these were neutropenic patients with haematological malignancy and 247 were patients with a normal or raised total white blood cell count and no haematological malignancy. Strains isolated from recurrent bacteraemia were also bio- and ribotyped. Overall, no significant difference was found between O serogroups, K antigens, serum sensitivity, production of haemolysin, expression of P-fimbriae and patterns of antibiotic susceptibility in the two groups of strains. The haematological patients more often than the non-haematological patients had an unknown focus of infection, recurrent bacteraemia, shorter intervals between recurrences and recurrences caused by identical strains. Despite a well-defined focus, six of eight non-haematological patients had recurrences with a strain different from the strain isolated in a previous episode. A possible connection between shorter intervals and recurrence with identical strains is discussed. We suggest that strains from recurrent E. coli bacteraemia are sent to a reference laboratory for serotyping and possibly ribotyping.

The surgical team as a source of postoperative wound infections caused by Streptococcus pyogenes

Postoperative wound infection, caused by Streptococcus pyogenes transmitted during the operation from members of the surgical team, is a rare but serious complication of surgery. This study describes three cases, which could be traced to an orthopaedic surgeon, who carried the epidemic strain in this throat. Epidemiological characteristics of 14 other outbreaks, published in the English-language literature, are summarized. In total, these 15 outbreaks involved 136 patients. The overall case fatality rate was 12%. Anaesthesiologists and other assisting staff members were involved more often than surgeons and obstetricians. In outbreaks where an attack rate could be calculated, it was at least 7%. T-28 was the most commonly involved T-type, accounting for seven outbreaks. The anus and vagina were the most common carrier sites in staff members. A combination of penicillin and oral vancomycin seemed to be the most efficient treatment for anal and vaginal carriage. Relapse of carriage could occur several months after apparent eradication, and was often associated with a carrier in the family household.

Development of cytomegalovirus (CMV) disease may be predicted in HIV-infected patients by CMV polymerase chain reaction and the antigenemia test

OBJECTIVE

Cytomegalovirus (CMV) is a frequent opportunistic viral pathogen in patients with AIDS leading to retinitis and other serious manifestations. CMV disease may be successfully treated. Prophylactic antiviral therapy has been shown to reduce the risk of CMV disease if initiated early. We evaluated PCR and the antigenemia tests as methods for early detection of CMV disease.

METHODS

Two-hundred HIV-seropositive subjects with CD4 T-cell counts below 100 x 10(6)/l were monitored with CMV polymerase chain reaction (PCR), the antigenemia test, blood cultures and CMV immunoglobulin (Ig) G and IgM titres every second month for 1 year.

RESULTS

Thirty-eight patients (19%) developed CMV disease. The PCR test detected CMV DNA a median of 46 days before onset of disease. This was earlier than the median of 34 for the antigenemia test and a median of 1 day for CMV blood cultures. Univariate analysis showed that the CMV PCR, the antigenemia test and blood cultures all had significant predictive values for subsequent development of CMV disease with odds ratios (OR) of 30, 22 and 20. CMV serology had no predictive value. Multivariate analysis showed that the PCR method was superior to the other tests; OR: CMV PCR 10.0, antigenemia test 4.4 and CMV cultures 4.3. No clinical parameters had any significant predictive value in the stepwise multivariate model.

CONCLUSIONS

The CMV PCR and the CMV antigenemia tests are both sensitive methods that may predict development of CMV disease up to several months prior to clinical disease. These methods make it possible to select patients at high risk for CMV disease and suitable for prophylactic therapy against CMV.

[Tuberculosis and the HIV pandemic. Risk of nosocomial tuberculosis infection]

Spread of human immunodeficiency virus (HIV) infection has had a major impact on the epidemiology of tuberculosis. In several African countries the incidence of tuberculosis has doubled, and the prevalence of HIV infection among patients with tuberculosis is 20 to 60%. A similar change has occurred in some developed countries. Several factors, including HIV infection, have contributed to this change. Tuberculosis among HIV infected patients is probably more often a result of a new infection with Mycobacterium tuberculosis than reactivation of a latent infection. In the USA in particular several outbreaks of multidrug-resistant tuberculosis have been reported. The mortality among patients has been high, and there have been several cases of transmission to healthcare workers. Analyses of these recent outbreaks indicate that it is possible to intervene by well known prophylactic measures. Rapid diagnosis and treatment, and correct isolation procedures are essential to prevent outbreaks.

Gentamicin concentrations in human subcutaneous tissue

Wound infections frequently originate from the subcutaneous tissue. The effect of gentamicin in subcutaneous tissue has, however, normally been evaluated from concentrations in blood or wound fluid. The aim of the present study was to investigate the pharmacokinetic properties of gentamicin in human subcutaneous adipose tissue by a microdialysis technique. Seven healthy young volunteers each had four microdialysis probes placed in the fat (subcutaneous) layer of the abdominal skin. After the administration of a 240-mg gentamicin intravenous bolus, consecutive measurements of the drug concentrations in serum and subcutaneous interstitial fluid were obtained simultaneously for 6 h. The tissue gentamicin concentration peaked after 10 to 30 min. The peak concentration in the tissue was 6.7 +/- 2.0 mg.liter-1 (standard deviation), equivalent to 39.1% of the peak concentration in serum. The area under the concentration-versus-time curve for the first 6 h in the tissue was 1,281 +/- 390.0) mg.min liter-1, equivalent to 59.7% of the area under the concentration-versus-time curve in serum. It is concluded that the microdialysis technique can be used to make dynamic and quantitative measurements of the gentamicin concentration in human subcutaneous tissue. In this adipose tissue, the peak concentrations of gentamicin were approximately seven times the MIC for Pseudomonas aeruginosa and 33 times the MIC for Staphylococcus aureus after the administration of an intravenous bolus of 240 mg, indicating the presence of sufficient concentrations in the adipose tissue to be effective against common bacteria.

Staphylococcus aureus carriage and infections among patients in four haemo- and peritoneal-dialysis centres in Denmark. The Danish Study Group of Peritonitis in Dialysis (DASPID)

A three-month prospective surveillance study was undertaken in four dialysis centres to establish the prevalence of Staphylococcus aureus carriage in a Danish population of patients on haemodialysis (HD) or on continuous ambulatory peritoneal dialysis (CAPD). General data such as sex, age, diagnosis, number of months in dialysis, hospital and ward were registered on a precoded form. Standardized nose and four skin swabs (axillae, groins, perineum) were performed on the first day of the survey. After one and two months, nose swabs were collected. Infections were registered and cultures were sent for phage-typing together with the S. aureus strains isolated from the swabs; 59.5% of HD patients and 51.2% of CAPD patients carried S. aureus. Permanent carriage was most frequent (P < 0.00009), primarily in the nose (44.0 and 34.9%, respectively in HD and CAPD). Skin carriage alone was rare (2.4 and 4.7%). Approximately one third (36.6 and 40.7%) of infections were caused by S. aureus. Although diabetics were not significantly more frequent carriers (60.5%) than non-diabetics (55.0%), the incidence of infection was much higher (26.3% vs. 10.3%, P = 0.004). In CAPD, peritonitis and tunnel/exit-site infections predominated (81.4%), often caused by S. aureus (34.8%). More than two thirds of the infections in HD patients were related to intravascular catheterization. The most serious infection was septicaemia, in all cases due to S. aureus. S aureus infections occurred significantly more frequently among carriers (P = 0.005), and more than half the patients were infected by the same or possibly the same strain as they carried in the nose or on skin. Different regimens for the elimination of S. aureus carriage in dialysis patients are discussed. A policy for risk assessment of patients should be developed, and the elimination of S. aureus carriage before dialysis should be encouraged. Controlled trials comparing the cost-effectiveness of recommended regimens to eliminate carriage in HD/CAPD patients are needed. Nose swabs are reliable indicators of carriage in dialysis patients.

[Vibrio vulnificus infections in Denmark during the summer of 1994]

The clinical manifestations and epidemiological data of 11 patients infected with Vibrio vulnificus found in Denmark during the unusually warm summer of 1994 are reported. All patients had been exposed to seawater prior to illness, but none had consumed seafood. Nine patients, including four with bacteraemia, developed skin manifestations of various degrees of severity. One patient died of septic shock despite surgery and treatment with relevant antibiotics. Four patients contracted the disease while fishing. High seawater temperature increases the risk of V. vulnificus infections even in temperate climates such as the Danish. Exposure to seawater, including handling of fresh seafood, during warm periods carries a risk of infection with V. vulnificus.

Coagulase-negative Staphylococci in Danish blood cultures: species distribution and antibiotic susceptibility

The distribution and antibiotic susceptibility of coagulase-negative staphylococci (CoNS) isolated from blood cultures was examined in samples from hospitals covering most of Denmark. A total of 499 CoNS isolates were detected in 477 blood cultures from 340 patients and speciated as Staphylococcus epidermidis, 285; Staphylococcus hominis, 61; Staphylococcus haemolyticus, 43; Staphylococcus warneri, 12; Staphylococcus cohnii, 7; Staphylococcus saprophyticus, 4; Staphylococcus capitis, 2 and Staphylococcus lugdunensis, 1. Seventy-eight isolates could not be identified to species level and six were Micrococcus spp. In 108 (22.6%) blood culture sets, more than one CoNS strain were found, as detected by species identification, antibiogram and biotyping. Significantly more blood cultures from patients in university hospitals were drawn from central venous catheters. Comparing university and non-university hospitals, the overall antibiotic susceptibility among CoNS was only slightly different, except for methicillin and amikacin. The prevalence of methicillin-resistant strains was 35.1% in the university hospital strains vs. 25.3% in the non-university hospital strains. The overall prevalence of methicillin resistance was 32%. Great geographic variation in both species distribution and antibiotic resistance was observed. The high prevalence of S. epidermidis makes subtyping of this species important.

[Infections related to central venous catheters]

Central venous catheters (CVC) are a major source of nosocomial bacteraemia. The majority of cases are due to Staphylococcus aureus and coagulase-negative staphylococci. Severe complications, in particular septic shock, develop in 30% of all CVC-associated septicaemia cases and are usually caused by S. aureus. Some patients develop metastatic suppurative complications. Risk factors include prolonged catheterization, localization of catheter to the groin, the number of times the system is entered, use for parenteral nutrition and for dialysis, immunosuppresion and loss of skin integrity especially in burns. Important measures to decrease the rate of CVC-related infections include aseptic technique during insertion, changing transparent semipermeable dressing at least every 48 hours and replacement of the entire delivery system every 72 h. Technological advances such as bonding antimicrobial agents to the intravascular device may reduce the risk of infection. Treatment of CVC-related infections usually requires catheter removal.