The search and destroy strategy prevents spread and long-term carriage of methicillin-resistant Staphylococcus aureus: results from the follow-up screening of a large ST22 (E-MRSA 15) outbreak in Denmark.

In the aftermath of a methicillin-resistant Staphylococcus aureus (MRSA) ST22 hospital outbreak, we investigated the prevalence of long-term carriage, the efficacy of MRSA decolonization treatment (DT) and the spread of MRSA to households of patients and healthcare workers (HCWs). Furthermore, we evaluated the efficacy of repeated DT in long-term MRSA carriers. Of 250 index persons (58 HCWs and 192 patients), 102 persons (19 HCWs and 83 patients) and 67 household members agreed to participate. Samples from all 169 persons were taken from the nose, throat, wounds and devices/catheters, and urine samples were additionally taken from index persons. Samples from companion animals (n = 35) were taken from the nostrils and anus. Environmental sites (n = 490) screened were telephone, television remote control, toilet flush handle, favourite chair and skirting board beside the bed. Sixteen (19%) patients and two household members, but no HCWs, were ST22-positive. The throat was the most frequent site of colonization. In a multivariate analysis, chronic disease (p <0.001) and pharyngeal carriage (p <0.001) were associated with long-term MRSA carriage. MRSA was found in the environments of four long-term carriers. All animals tested were negative. MRSA-positive households were decolonized using nasal mupirocin TID and daily chlorhexidine body and hair wash for 5 days. Pharyngeal MRSA carriers also received fucidic acid (500 mg TID) combined with rifampicin (600 mg BID) or clindamycin (600 mg BID) for 7 days. The home environment was cleaned on days 2 and 5. At the end of follow-up, ten of 16 long-term carriers and the two household contacts were MRSA-negative. In conclusion, decolonization of MRSA carriers is possible, but should include treatment of household members and the environment.

Screening for methicillin-resistant Staphylococcus aureus in clinical swabs using a high-throughput real-time PCR-based method.

The presence of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals and the community is a serious problem. Accordingly, a comprehensive plan has been implemented in the County of Vejle, Denmark, to identify colonised and/or infected individuals and to control the spread of MRSA. Since 2005, all patients and healthcare personnel have been screened for MRSA colonisation, involving analysis of 300-400 samples daily. To deal with this number of samples, a PCR-based method customised for high-throughput analysis and a system for fast reporting of MRSA carrier status were developed. Swab samples were incubated overnight in a selective tryptone soya broth and were analysed by PCR the following day. Using this strategy, non-colonised individuals were identified within 24 h, while MRSA-positive samples were analysed further by traditional microbiological methods to determine the resistance pattern. This is a cost-effective approach, as the greatest expense in hospitals involves the isolation of patients of unknown MRSA status. The method was evaluated by testing 2194 clinical samples, with a sensitivity and specificity of 100% and 94%, respectively. The analytical sensitivity was 97%, with 161 of 166 different MRSA strains and isolates generating positive results according to PCR analysis. Using four control strains, the inter-assay variation was revealed to be a maximum of 2.6%, indicating good reproducibility.

Quantification of Staphylococcus aureus and Staphylococcus epidermidis on the hands of health-care workers using a real-time polymerase chain reaction method.

OBJECTIVE: The objective of this study was to test a polymerase chain reaction (PCR) assay intended as a tool for monitoring hand hygiene in hospital wards. METHODS: The hands of 20 health-care workers were sampled for 10 days using real-time PCR for quantification of Staphylococcus aureus and S. epidermidis. Reference intervals (CI) and biological variation were evaluated using index of individuality (II) and critical difference (CD). RESULTS: 45% of the participants were positive for S. aureus on all 10 days. Intra-individual biological variation (CVI) was 129% for S. aureus and 62% for S. epidermidis. Inter-individual biological variation (CVG) was 245% for S. aureus and 107% for S. epidermidis. II was 0.55 for S. aureus and 0.71 for S. epidermidis, indicating a high degree of individuality and limited use of the reference values. A significant individual change was determined at 374% for S. aureus and 211% for S. epidermidis. In an intervention study aimed at better hand hygiene in a ward with n participants, the difference before and after intervention is significant at CDI/sqrt[n] per cent. CONCLUSIONS: The PCR assay can be used to detect change in a group mean of S. aureus and S. epidermidis in a hospital ward, i.e. before and after an intervention to improve hand hygiene. For the individual, the change in bacteria levels needed for significance is compromised by high intra-individual variation.

Azithromycin versus pivampicillin in the treatment of acute exacerbations of chronic bronchitis: a single-blind, double-dummy, multicentre study.

This single-blind, double-dummy, multicentre study compared oral azithromycin, administered as tablets, 500 mg once daily for 3 days, versus oral pivampicillin, 700 mg twice daily for 10 days, in adults with acute exacerbations of chronic bronchitis (not needing parenteral antibiotic therapy, hospitalization or oxygen support). Clinical success (cure + improvement) rates were similar for both groups at the end of treatment (day 10; azithromycin, 124 of 133 [93%]; pivampicillin, 79 of 92 [86%]) and at follow-up (day 52; 98 of 126 [78%] versus 66 of 81 [81%]). The treatments produced similar levels of pathogen eradication at the end of treatment (49 of 54 [91%] versus 32 of 37 [86%]). Azithromycin-treated patients had significantly reduced chest discomfort at the end of treatment, and a trend towards improved lung function. The two groups were similar with respect to improvements in other clinical symptoms and patient well-being, and to the incidences of adverse events and treatment discontinuations. This oral azithromycin regime is an effective treatment for acute exacerbations of chronic bronchitis, similar in efficacy to the longer pivampicillin regime and may offer superior patient compliance.

Azithromycin Concentrations and Microbiology of Tonsils during Weekly Medication in Patients with Recurrent Tonsillitis.

This study was performed in order to assess whether 500mg of azithromycin given orally once per week could produce tonsil tissue concentrations above minimum inhibitory concentrations for key target pathogens in patients with recurrent tonsillitis. For the measurement of tissue concentrations an automated solid phase extraction (SPE) method for cleaning the tissue extracts was developed. Concomitantly, the influence of this treatment on the microbiological flora of the tonsillar surface was monitored. The mean concentration of azithromycin in the tonsillar tissue was 1.8 microg/g (0.4 microg/g to 5.1 microg/g), i.e. therapeutic concentrations of azithromycin were found in most tonsils 1 week after medication. The validated SPE method developed provided a clean extract for high performance liquid chromatographic determination of azithromycin. The surface microbiology of the tonsils at surgery showed the usual pathogens in most patients. In conclusion, therapeutic levels of azithromycin were present in tonsil tissue during weekly medication with minimal influence on surface microbiology. A placebo-controlled, double-blind study of long-term treatment is in progress.

[Outbreak of methicillin resistant Staphylococcus aureus in a central hospital]. / Udbrud af methicillinresistent Staphylococcus aureus på et centralsygehus.

Until 1994, methicillin resistant Staphylococcus aureus (MRSA) were isolated from less than 60 patients annually in Denmark. We describe an outbreak of MRSA involving eight patients within a timespan of six weeks. Bacteriophage-typing and DNA typing using pulsed field gel electrophoresis revealed that three different strains of MRSA were involved in the outbreak. This emphasizes the importance of typing MRSA in order to clear up the spread in an outbreak. Of the eight patients four died, and in one case MRSA was thought to be the major cause of death. The expenses of the extra hygienic measures i.e. isolation of patients, medication and bacteriological surveillance were estimated to approximately DKK 80.000 pr. patient. Patients, who have been admitted to or worked at a hospital outside Scandinavia within the last six months, are potentially colonized with MRSA. Specific guidelines for hospital hygiene are necessary to prevent the spread of such strains.

[Vibrio vulnificus infections in Denmark during the summer of 1994]. / Vibrio vulnificus-infektioner i Danmark sommeren 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.

Prevalence and antibiotic sensitivity of Danish versus other European bacterial isolates from intensive care and hematology/oncology units.

The prevalence and antibiotic sensitivity patterns of bacteria collected consecutively from medical and surgical intensive care units (ICUs) and from hematology/oncology units in nine hospitals in Denmark were determined and compared to data collected simultaneously in 12 other European countries. Bacterial isolates from 794 Danish patients were tested and compared to 8,625 isolates from European patients. The minimal inhibitory concentrations of eight different antibiotics were determined using a microdilution plate. Similar to findings in European countries, the most common source of bacterial isolates in Danish units was the respiratory tract (49%), followed by blood (18%), urinary tract (14%) and surgical wounds (10%). Staphylococcus aureus was the most prevalent respiratory organism in Danish units, whereas Enterobacteriaceae and Pseudomonas aeruginosa dominated in other countries. In blood, Escherichia coli was most prevalent in Denmark while coagulase-negative staphylococci were predominant in other countries. Urinary tract isolates were dominated by Escherichia coli in both Denmark and the other countries, but Enterococcus faecalis and Pseudomonas aeruginosa were more frequently isolated in the other countries. Staphylococcus aureus was the most frequent wound isolate in Denmark, while Enterobacteriaceae other than Escherichia coli dominated in other European countries. Thus, in Denmark Escherichia coli and Staphylococcus aureus, followed by Pseudomonas aeruginosa and Klebsiella spp. (from ICUs) or Enterococcus spp. and Klebsiella spp. (from hematology/oncology units), are the most prominent pathogens in these units today. Indicator organisms of antibiotic consumption (Pseudomonas aeruginosa and methicillin-resistant coagulase-negative staphylococci and Staphylococcus aureus) were more frequent in other European countries than Denmark. In general the Danish isolates were more sensitive to antibiotics than the European isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional variation in the use of antibiotics in four Danish hospitals.

The increasing use of antibiotics contributes to the selection of resistant bacteria and to the cost of health care. Large regional differences in the use of antibiotics between and within countries exist. This study describes such usage in four Danish hospitals, and includes a comparison with that of the average of 450 US hospitals. Compared to the Danish hospitals, the US hospitals used approximately double the amount of antibiotics in defined daily dosages (DDD)/100 bed days. In contrast to the comparison with the American hospitals no real differences were found comparing the four Danish hospitals. The four Danish hospitals differed in degree of specialization, presence of a clinical microbiological department or a hospital pharmacy. Use of antibiotics, in DDD/100 bed days, was highest in the hospital without a department of clinical microbiology, while the highest cost of antibiotics/admission was found in the hospital with the highest degree of specialization. Restraint in antibiotic usage calls for the joint efforts of the department of clinical microbiology, the hospital pharmacy and the local drug committee - the most important tools being: continuous education, audits of antibiotic use, provision of guidelines and recommendations, facilities for rapid diagnosis of infectious diseases, and limitation of the number of antibiotics used in routine sensitivity testing.

Efficacy of perioperative ceftazidime in the surgical treatment of chronic otitis media due to Pseudomonas aeruginosa. Preliminary report of a prospective, controlled study.

A prospective open and controlled study of perioperative antibiotics was conducted in patients with chronic otitis media (COM). Drug efficacy was found in a subgroup of 26 patients, who were characterized by preoperative aural drainage culturing Pseudomonas aeruginosa. Fourteen of these patients were randomized to receive ceftazidime (cephalosporin) for 5 days at the operation, while 12 had no antibiotic treatment. The occurrence of subsequent aural drainage was compared with the actual clinical and microbiological conditions of the ears 2 months after the operation; statistically significant differences were found in favor of the group treated with ceftazidime. Further studies must define the role of ceftazidime and other antibiotics in the management of patients with COM.

Six cases of acute appendicitis with secondary peritonitis caused by Streptococcus pneumoniae.

In six previously healthy children and adults with typical acute appendicitis, Streptococcus pneumoniae was isolated from peritoneal swabs or periappendicular pus in pure culture (four patients) or together with intestinal flora. Pneumococci recovered by abdominal paracentesis are not pathognomonic of socalled primary or spontaneous peritonitis.

In vitro activity of azlocillin, carbenicillin, mezlocillin and piperacillin against Pseudomonas aeruginosa.

50% inhibitory concentration (IC50) of azlocillin, carbenicillin, mezlocillin and piperacillin against 157 strains of P. aeruginosa were determined by means of the agar plate-dilution method. The 3 new semisynthetic penicillins were significantly more active against P. aeruginosa than carbenicillin; azlocillin and piperacillin were 8-fold, and mezlocillin was 2-4-fold more active than carbenicillin. More than 95% of the P. aeruginosa strains were inhibited by 16 micrograms/ml of azlocillin or piperacillin whereas 64 micrograms/ml of mezlocillin and 256 micrograms/ml of carbenicillin, respectively, were necessary to inhibit 95% of the strains.