Johan Wiström

Empiric Treatment of Acute Diarrheal Disease with Norfloxacin: A Randomized, Placebo-Controlled Study

OBJECTIVE To evaluate the clinical and microbiologic efficacy and safety of norfloxacin for acute diarrhea. DESIGN Double-blind, placebo-controlled, randomized clinical multicenter trial. SETTING Six departments of infectious disease. PARTICIPANTS Patients 12 years of age or older with a history of acute diarrhea lasting 5 or fewer days. Eighty-five percent of patients (511/598) were evaluable for efficacy. Of these evaluable patients, 70% had traveled abroad within the previous 6 weeks. INTERVENTIONS Patients received either norfloxacin, 400 mg, or placebo twice daily for 5 days. MEASUREMENTS Enteric pathogens were isolated in 51% of the evaluable patients: Campylobacter species in 29%, Salmonella species in 16%, Shigella species in 3.5%, and other pathogens in 2.6%. RESULTS Norfloxacin had a favorable overall effect compared with placebo (cure rate, 63% compared with 51%; P = 0.003). There were statistically favorable effects in culture-positive patients, patients with salmonellosis, and severely ill patients but not in culture-negative patients or patients with campylobacteriosis or shigellosis. A significant difference was noted between norfloxacin and placebo in median time to cure among all evaluable patients (3 compared with 4 days, P = 0.02) and in patients with campylobacteriosis (3 compared with 5 days, P = 0.05) but not in patients. Culture-positive, but not culture-negative patients, in the norfloxacin group had significantly fewer loose stools per day compared with patients in the placebo group from day 2 onward (P less than or equal to 0.01). Norfloxacin was significantly less effective than placebo in eliminating Salmonella species on days 12 to 17 (18% compared with 49%, P = 0.006), whereas the opposite was true for Campylobacter species (70% compared with 50%, P = 0.03). In six of nine patients tested, norfloxacin-resistant Campylobacter species (MIC, greater than or equal to 32 micrograms/mL) appeared after norfloxacin treatment. CONCLUSION Empiric treatment reduced the intensity and, to some extent, the duration of symptoms of acute diarrhea. The effect was restricted to patients who had bacterial enteropathogens or who were severely ill. The clinical usefulness of this treatment is limited by the fact that norfloxacin seems to delay the elimination of salmonella and to induce resistance in campylobacter.

Coagulase-negative staphylococci : update on the molecular epidemiology and clinical presentation, with a focus on Staphylococcus epidermidis and Staphylococcus saprophyticus

Coagulase-negative staphylococci (CoNS), originally described as ubiquitous commensals of the healthy human skin and mucosa, have emerged as important opportunistic pathogens primarily causing healthcare-associated infections in patients with indwelling medical devices. Recent studies, utilizing new molecular typing methods, particularly on Staphylococcus epidermidis, have increased our understanding of the mechanisms that contribute to the evolutionary success of these extremely versatile microorganisms. In the following mini-review, we summarize recent research in this area focusing on the molecular methods and epidemiology of S. epidermidis and S. saprophyticus.

Booster vaccination with recombinant hepatitis B vaccine four years after priming with one single dose

We here studied the antibody response to a booster dose four years after the administration of one single dose of recombinant HB vaccine. Before receiving the booster dose, levels of protective antibodies (anti-HBs) were generally low and 24/41 (59%) individuals lacked detectable antibodies (< 1 IU/L). Within 14 d of booster vaccination, 36/38 (95%) vaccinees showed levels of antibodies > 100 IU/L. Notably, these levels were at least as high as those of a reference group 12 months after initiation of vaccination according to the standard three-dose vaccination at intervals of 0, 1 and 6 months. In conclusion, one single dose of HB vaccine seemed to confer on young healthy individuals a well preserved B cell memory, disclosed as a rapid and strong antibody response to a second dose four years later.

Health Problems and Self-medication among Swedish Travellers

500 consecutive travellers seeking pre-travel health advice were issued a questionnaire before leaving Sweden to continuously record health problems and use of medication during travel. Of 442 subjects who turned in assessable questionnaires (232 male and 210 female, mean age 37 years), 81% travelled to areas at high risk for the acquisition of diarrhea. The mean duration of travel was 4 weeks. During travel 218 (49% at 95% CI 44.3 to 53.7%) of the travellers experienced some illness and 61 (14%) had symptoms of more than one illness. The mean duration of illness was 4.5 days, and 65 subjects (30% of ill travellers) were confined to bed for a mean duration of 2 days. The incidence of illness was significantly (p < 0.01) higher among travellers to high risk than to low risk areas (55% vs 26%), among young travellers than among elderly (65% vs 33%), and among those going on adventure tours compared with recreational tourists (74% vs 41%). Diarrhea was reported by 36% (95% CI 31.6 to 40.5%), and respiratory tract infection by 21% (95% CI 17.2 to 24.8%). Self-medication with one or several drugs was initiated by 163 (75%) travellers experiencing illness during travel. Thus, every second Swedish traveller to tropical and subtropical areas experienced some kind of travel-related, often incapacitating, health problem.

SPREAD OF CLONES OF MULTIDRUG-RESISTANT, COAGULASE-NEGATIVE STAPHYLOCOCCI WITHIN A UNIVERSITY HOSPITAL

OBJECTIVE To detect putative clonal dissemination of multidrug-resistant, coagulase-negative staphylococci (CNS) in a university hospital in northern Sweden. METHODS All consecutive routine clinical samples from our hospital were screened during two periods (November and December 2001 and September and October 2002) for the presence of multidrug-resistant (defined as resistant to oxacillin, clindamycin, co-trimoxazole, gentamicin, and fusidic acid, but susceptible to vancomycin) isolates of CNS. Genetic similarity between isolates was analyzed using pulsed-field gel electrophoresis (PFGE) and a computer program. RESULTS Seventy multidrug-resistant isolates from 62 patients were identified, 28 during the 2001 period and 42 during the 2002 period. All isolates except one, which was Staphylococcus haemolyticus, were identified as S. epidermidis. Multidrug-resistant CNS were isolated in samples obtained from 24 different wards. Two subgroups (group A and group B) of S. epidermidis that differed by approximately 40% in PFGE band similarity were identified. Group A consisted of 44 isolates with a PFGE band similarity of greater than 70% that included 6 subgroups consisting of 3 to 16 isolates that expressed a 100% similarity. These isolates were identified during both sampling periods in cultures performed in 18 different wards. A clonal origin could not be excluded for some of the remaining 26 isolates belonging to group B, but none had identical PFGE patterns, suggesting a more diverse origin. CONCLUSION The results of this study suggest clonal spread of multidrug-resistant CNS within our hospital and that some clones are endemic in the hospital environment.

An inexpensive and reliable method for routine identification of staphylococcal species

The aim of this study was to develop a simple, reliable, and inexpensive in-house system for routine species identification of staphylococci in clinical practice. The system combines 15 key tests (including carbohydrate fermentation) performed in micro-well strips and antimicrobial disk diffusion susceptibility tests performed on standardised paper disk method antibiotic sensitivity medium agar. Twenty-eight Staphylococcal reference strains belonging to 18 different species were correctly identified using this in-house system. A total of 291 clinical staphylococci isolates were evaluated with the in-house system and a conventional identification scheme. The in-house system identified 281 (96.6%) of these 291 isolates. Eleven different species were recognised. The five species most frequently identified wereStaphylococcus epidermidis (48.6%),Staphylococcus aureus (27.8%),Staphylococcus haemolyticus (8.2%),Staphylococcus hominis (5.7%), andStaphylococcus warneri (5.3%). There was an agreement of 86.3% between the species identification obtained with the in-house system and the conventional identification scheme. All coagulase-negative isolates initially identified as species other thanStaphylococcus epidermidis as well as indistinctly identified isolates were also evaluated with a commercial identification system. The agreement between species identification obtained with the inhouse system and the commercial system for 101 identified isolates was 73%. Several isolates that were difficult to distinguish with the conventional scheme and/or the commercial system were identified with the aid of the antimicrobial susceptibility test included in the in-house system. The described test scheme should be of value for identification of clinically significant staphylococci species.

Multiple-locus variable-number tandem repeat analysis for typing of Staphylococcus epidermidis.

ABSTRACT We applied a high-resolution PCR-based typing method, multiple-locus variable-number tandem repeat analysis (MLVA), for discrimination of 30 multidrug-resistant clinical isolates of Staphylococcus epidermidis. The results of MLVA were congruent with results obtained by pulsed-field gel electrophoresis (PFGE). MLVA generated discrete character data, and its discriminatory capacity was comparable to that of PFGE.

A Case of Plesiomonas shigelloides Cellulitis and Bacteraemia from Northern Europe

Bacteremia caused by Plesiomonas shigelloides is a rare event, often associated with consumption of seafood and fresh or estuarine water in temperate or tropical climates. Most patients have showed underlying health disorders. Here we present a case of P. shigelloides septicaemia and cellulitis of the left hand associated with fish handling in Northern Sweden (65 degrees latitude north). The patient, who suffered from multiple myeloma, recovered uneventfully after initial treatment with intravenous cefuroxime followed by a course of oral ciprofloxacin. P. shigelloides seems to be ubiquitous in freshwater world-wide and may cause invasive infections also in cold climate areas.

Clonality among multidrug-resistant hospital-associated Staphylococcus epidermidis in northern Europe

Using pulsed-field gel electrophoresis (PFGE) we have previously described the occurrence and possible dissemination of a clone of multidrug-resistant Staphylococcus epidermidis (MDRSE) in 2 hospitals in northern Sweden during 2001–2003. The aims of the present study were to investigate if this clone still persisted, 7 y later, in these 2 hospitals and whether this specific clone was detectable among clinical isolates from 9 other hospitals, 6 Swedish as well as a Norwegian, Danish and a German hospital. In total, 173 clinical isolates of MDRSE isolated during 2003 to 2008 were analysed using PFGE, of which 22 isolates were also characterized by multilocus sequence typing (MLST). Two dominating PFGE types (types A and B) were identified, consisting of 56 (32%) and 38 (22%) isolates, respectively. Type A, which was detected in the Norwegian and all Swedish hospitals, proved indistinguishable to the clone previously identified in 2001–2003 and corresponded with a novel sequence type (ST215). Type B was discovered in the German, Danish and in 7 Swedish hospitals and corresponded with ST2. In conclusion, we have demonstrated the occurrence, persistence and potential dissemination of 2 MDRSE genotypes, including a novel sequence type (ST215), within hospitals in northern Europe.

Molecular Epidemiology of Staphylococcus saprophyticus Isolated from Women with Uncomplicated Community-Acquired Urinary Tract Infection

ABSTRACT Staphylococcus saprophyticus is a common cause of urinary tract infections (UTIs) in women. Little is known about the molecular epidemiology of S. saprophyticus UTIs. In the current study, we compared 76 isolates of S. saprophyticus prospectively isolated from women with uncomplicated UTI participating in a randomized placebo-controlled treatment trial performed in northern Sweden from 1995 to 1997 with 50 strains obtained in 2006 from five different locations in northern Europe with pulsed-field gel electrophoresis (PFGE). The aim was to elucidate the molecular epidemiology of this uropathogenic species and to investigate whether specific clones are associated with UTI in women. A total of 47 different PFGE profiles were detected among the 126 analyzed isolates. Ten clusters consisting of 5 to 12 isolates each showing PFGE DNA similarity of >85% were identified. Several clusters of genetically highly related isolates were detected in the original trial as well as among isolates obtained during 2006 from different locations. In the original trial, clonal persistence was found among 16 of 21 (76%) patients examined in the placebo group at follow-up 8 to 10 days after inclusion, indicating a low spontaneous short-time bacteriological cure rate. We conclude that multiple clones of S. saprophyticus were causing lower UTIs in women. The result suggests that some human-pathogenic clones of S. saprophyticus are spread over large geographical distances and that such clones may persist over long periods of time.