Antibiotic resistance of motile aeromonads in indoor catfish and eel farms in the southern part of The Netherlands

The prevalence and degree of antibiotic resistance in catfish and eel farms in the southern part of The Netherlands was examined using motile aeromonads as indicator bacteria. A total of 29 water samples were collected, originating from six catfish farms, one catfish hatchery and three eel farms, and were plated on an Aeromonas-selective agar with and without antibiotics. From each plate, one colony was screened for presumptive motile aeromonads and tested for antibiotic susceptibility. The prevalence of resistance was as follows: ampicillin and oxytetracycline 100%; sulfamethoxazole 24%; trimethoprim 3%; and ciprofloxacin and chloramphenicol 0%. The majority of samples showed a high degree of oxytetracycline resistance, implicating fish farms as a major reservoir of oxytetracycline resistance genes. This reservoir might form a risk for human health and has major consequences for the effectiveness of this antibiotic in the treatment of infectious diseases in fish.

The role of the intestinal microbiota in the development of atopic disorders

The prevalence of atopic diseases, including eczema, allergic rhinoconjunctivitis and asthma, has increased worldwide, predominantly in westernized countries. Recent epidemiological studies and experimental research suggest that microbial stimulation of the immune system influences the development of tolerance to innocuous allergens. The gastrointestinal microbiota composition may be of particular interest, as it provides an early and major source of immune stimulation and seems to be a prerequisite for the development of oral tolerance. In this review the observational studies of the association between the gut microbiota and atopic diseases are discussed. Although most studies indicated an association between the gut microbiota composition and atopic sensitization or symptoms, no specific harmful or protective microbes can be identified yet. Some important methodological issues that have to be considered are the microbiological methods used (traditional culture vs molecular techniques), the timing of examining the gut microbiota, the definition of atopic outcomes, confounding and reverse causation. In conclusion, the microbiota hypothesis in atopic diseases is promising and deserves further attention. To gain more insight into the role of the gut microbiota in the etiology of atopy, large-scale prospective birth cohort studies using molecular methods to study the gut microbiota are needed.

The molecular evolution of methicillin-resistant Staphylococcus aureus

Staphylococcus aureus is a potentially pathogenic bacterium that causes a broad spectrum of diseases. S. aureus can adapt rapidly to the selective pressure of antibiotics, and this has resulted in the emergence and spread of methicillin-resistant S. aureus (MRSA). Resistance to methicillin and other beta-lactam antibiotics is caused by the mecA gene, which is situated on a mobile genetic element, the Staphylococcal Cassette Chromosome mec (SCCmec). To date, five SCCmec types (I-V) have been distinguished, and several variants of these SCCmec types have been described. All SCCmec elements carry genes for resistance to beta-lactam antibiotics, as well as genes for the regulation of expression of mecA. Additionally, SCCmec types II and III carry non-beta-lactam antibiotic resistance genes on integrated plasmids and a transposon. The epidemiology of MRSA has been investigated by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), spa typing and SCCmec typing. Numerous MRSA clones have emerged and disseminated worldwide. SCCmec has been acquired on at least 20 occasions by different lineages of methicillin-sensitive S. aureus. Although most MRSA strains are hospital-acquired (HA-MRSA), community-acquired MRSA (CA-MRSA) strains have now been recognised. CA-MRSA is both phenotypically and genotypically different from HA-MRSA. CA-MRSA harbours SCCmec types IV or V, and is associated with the genes encoding Panton-Valentine leukocidin. The prevalence of MRSA ranges from 0.6% in The Netherlands to 66.8% in Japan. This review describes the latest developments in knowledge concerning the structure of SCCmec, the molecular evolution of MRSA, the methods used to investigate the epidemiology of MRSA, and the risk-factors associated with CA-MRSA and HA-MRSA.

Molecular fingerprinting of the intestinal microbiota of infants in whom atopic eczema was or was not developing

BACKGROUND

The rise in atopic diseases has been linked to disturbances in the intestinal microbiota composition.

OBJECTIVE

The purpose of this study was to investigate the intestinal microbiota composition in infants in whom atopic (IgE-associated) eczema was or was not developing, using a molecular fingerprinting technique.

METHODS

Within a prospective birth cohort study, fecal samples have been collected at the infant's age of 1 month. Within the context of this cohort, we conducted a nested case-control study comparing fecal samples of 26 infants who became sensitized and developed eczema within the first year of life with 52 non-sensitized non-eczematous infants. The composition of the fecal samples was examined using PCR combined with denaturing gradient gel electrophoresis. Using real-time PCR, total bacterial counts and bifidobacterial counts were enumerated.

RESULTS

Neither total bacterial profiles nor the type and proportion of bifidobacteria in the feces were associated with the development of atopic eczema. The similarity of bacterial profiles was low; mean similarity was approximately 33% in both infants with or without atopic eczema. The prevalence of one specific band in total bacterial profiles was significantly higher in infants with atopic eczema compared with controls (96% vs. 71%, P = 0.01). Identification of this band revealed that it represented Escherichia coli.

CONCLUSION

Although no association was found between the development of IgE-associated eczema and the dominant gut microbiota as a whole or with the bifdobacterial microbiota, the association with E. coli indicates that differences in gut microbiota do precede the development of atopy.

Urinary tract infections in general practice patients: diagnostic tests versus bacteriological culture

OBJECTIVES

Urinary tract infections (UTIs) are common bacterial infections encountered in general practice. For the optimal treatment the general practitioner (GP) should rely on the results of diagnostic tests and recent antimicrobial susceptibility of uropathogens.

PATIENTS AND METHODS

In total 1993 female patients (11-70 years) with complaints of an acute uncomplicated UTI were included. The performance characteristics of the diagnostic tests used were determined and compared with the antibiotic prescription rate. The antibiotic therapy (agent and duration), the uropathogens and the antibiotic susceptibility of Escherichia coli were determined for each age group.

RESULTS

The positive predictive value (PPV) (96%) and the specificity (94%) of the nitrite test were high for all samples. A negative nitrite with a positive leucocyte-esterase (LE) test showed a high PPV (79%) and sensitivity (82%). When both nitrite and LE tests were negative approximately 50% of the samples were culture positive. Of the patients, 94% of those with a positive nitrite test and 71% of those with a negative nitrite and positive LE test were prescribed antibiotics, mostly nitrofurantoin and trimethoprim. Nitrofurantoin prescriptions decreased and those of fluoroquinolones increased with increasing age. Nitrofurantoin was equally prescribed for 3-7 days in all patients. Trimethoprim was mostly prescribed for 3 days in patients aged 21-50 years and for 5 days in the other patients. E. coli, the uropathogen mostly isolated, decreased in frequency with increasing age. Proteus mirabilis was found more in the oldest patients and Staphylococcus saprophyticus in the younger patients. The antimicrobial susceptibility of E. coli was not age related. The lowest percentages were found for amoxicillin (67%) and trimethoprim (77%). Fluoroquinolone resistance was emerging in the older patients.

CONCLUSIONS

For female patients with symptoms of an acute uncomplicated UTI a positive nitrite test or a negative nitrite test with a positive LE test confirmed UTI whereas a negative nitrite together with a negative LE test did not rule out infection. For empirical treatment GPs should take into account the changing aetiology with increasing age. Prudent use of antibiotics in general and more specifically fluoroquinolones remains recommended. As trimethoprim resistance reached 20% it might be advisable to no longer use it as therapy of first choice for acute uncomplicated UTIs in The Netherlands.

[A study of non-antibiotic versus antibiotic prophylaxis for recurrent urinary-tract infections in women (the NAPRUTI study)]

Patient enrolment in the 'Non-antibiotic versus antibiotic prophylaxis for recurrent urinary-tract infections' (NAPRUTI) study was started in September 2005. In this study of women with recurrent urinary-tract infections we aim to investigate the effect of 12 months of non-antibiotic prophylaxis in comparison with antibiotic prophylaxis on the rate of recurrence of urinary-tract infections and the development of antibiotic resistance. The study consists of two interlinked, randomised, clinical non-inferiority trials. In one trial, 280 premenopausal women will receive either cranberry capsules (twice daily 500 mg) or standardised antibiotic therapy (once daily 480 mg trimethoprim-sulfamethoxazole). In the other trial, 280 postmenopausal women will receive either oral lactobacilli (twice daily a capsule with > 10(9) colony-forming units of Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14) or standardised antibiotic therapy. Non-inferiority of non-antibiotic prophylaxis would be attractive given its potential to reduce the prevalence of microbial resistance to antibiotics significantly.

Antibiotic treatment and resistance of unselected uropathogens in the elderly

A population-based study was conducted among women over the age of 70 years with complaints of uncomplicated urinary tract infections (UTIs). The positive predictive value of the nitrite test alone or in combination with the leukocyte esterase test ranged between 83% and 99%. The nitrofurantoin prescription rate decreased whereas fluoroquinolone and amoxicillin/clavulanic acid prescriptions increased with increasing age. The aetiology of infection was age-dependent. Escherichia coli was the most commonly isolated uropathogen, followed by Proteus mirabilis and Klebsiella pneumoniae. For these uropathogens, the lowest susceptibility percentages were found for amoxicillin, trimethoprim and co-trimoxazole. As trimethoprim susceptibility reached approximately 75%, it may be advisable not to use this as a first-choice agent in the treatment of uncomplicated UTIs in the elderly.

The effect of a probiotic drink with Lactobacillus plantarum 299v on the bacterial composition in faeces and mucosal biopsies of rectum and ascending colon

BACKGROUND

Studies on probiotics mainly base their results on faecal samples, which may not represent the situation in the mucosa of distal and proximal colon.

AIM

In a placebo-controlled study, to assess the effect of Lactobacillus plantarum 299v on the bacterial composition of faecal vs. mucosal samples.

METHODS

Twenty-nine patients undergoing colonoscopic examination for polyps consumed a twice-daily drink with or without L. plantarum 299v (10(11) CFU/day) for 2 weeks. Faecal samples were collected before and after consumption. During colonoscopy, biopsies were collected from the ascending colon and rectum. The faecal and mucosal bacterial concentrations and prevalence were determined.

RESULTS

L. plantarum 299v significantly increased the concentration of faecal lactic acid bacteria, lactobacilli and clostridia, and was identified in two rectal biopsies but not in the ascending colon biopsies of probiotic-treated subjects. Concentrations and prevalence in ascending colon and rectum biopsies were comparable, but were significantly lower compared with faecal samples.

CONCLUSIONS

After probiotic consumption, a significant increase in the faecal concentration of lactobacilli was found but concentrations were low in biopsies. The bacterial composition in biopsies of the ascending colon and rectum did not differ based on culture techniques. To further elucidate the modes of action of probiotics, it might be necessary to study differences in colonization with molecular techniques.

Plan-do-study-act cycles as an instrument for improvement of compliance with infection control measures in care of patients after cardiothoracic surgery

The aim of this study was to determine whether compliance with infection control measures for the care of patients during and after cardiothoracic surgery could be improved by using 'plan-do-study-act' (PDSA) improvement cycles in a 715-bed university hospital. The endpoints of these cycles were indices of correct procedure based on infection control standards. The intervention consisted of instruction and training of nursing and medical staff on the use of PDSA cycles, feedback of the baseline measurements, and the use of posters in the proximity of the operating room (OR). At follow-up, overall compliance only improved in the room used by the perfusionists and the OR. After the follow-up period, monitoring revealed a drop in compliance in the OR, but improved compliance during vascular catheter care of patients with prolonged stay in the intensive care unit (ICU), and during wound care of patients on the nursing ward. The last series of monitoring showed that compliance with general infection control measures in the OR had improved again, and that compliance had remained satisfactory on the ward and in the ICU, with the exception of patients recently transferred to the ICU from the OR. The results show that by using PDSA cycles, compliance with infection control measures can improve significantly. However, repeated monitoring is necessary to ensure continued compliance.

Erythromycin resistance in the commensal throat flora of patients visiting the general practitioner: a reservoir for resistance genes for potential pathogenic bacteria

The prevalence and mechanism of erythromycin resistance in commensal throat streptococci was determined from October 2000 until December 2002 as part of an ongoing study of the NIVEL in general practice patients (N=678). Resistance prevalence for 1mg/L and 16 mg/L erythromycin was 57% and 20%, respectively. The percentage of total commensal flora resistant within each patient ranged from 1% to 100% (median, 1%). mefA was predominantly found among isolates on the 1mg/L plates, and ermB was found in 64% of the isolates on the 16 mg/L plates. Erythromycin resistance was transferred from a commensal isolate to Streptococcus pneumoniae with a frequency of 1 x 10(-9). Commensal streptococci of general practice patients in The Netherlands form a large reservoir of transferable erythromycin resistance (genes) for potential pathogenic microorganisms.

Effect of Hospitalization on the Antibiotic Resistance of FecalEnterococcus faecalisof Surgical Patients Over Time

The prevalence of antibiotic resistant Enterococcus faecalis was determined in fecal samples of 263 patients admitted to the surgical wards of three university-affiliated hospitals on admission, at discharge, and at 1 and 6 months after discharge. A slight increase in the prevalence of antibiotic resistance of E. faecalis was found at discharge for the antibiotics tested compared to those on admission, vancomycin excepted. At 6 months after discharge, the prevalence of resistance for amoxicillin (0%), ciprofloxacin (3%), erythromycin (47%), and oxytetracycline (60%) decreased to the level on admission (respectively 0%, 8%, 45%, and 64%). Gentamicin resistance was the same at discharge (10%) as 1 month later (12%), but decreased 6 months after discharge (8%) to the level on admission (7%). In conclusion, hospitalization resulted in the study population in a slight increase in the prevalence of resistant fecal E. faecalis isolates at discharge, which decreased again (slowly) to the level on admission 6 months after discharge. Thus, the influence of hospitalization on the prevalence of antibiotic resistance in the extramural situation disappears between 1 and 6 months after discharge in this population.

Clinical items not helpful in differentiating viral from bacterial lower respiratory tract infections in general practice

OBJECTIVE

Incorrect and unnecessary antibiotic prescribing enhancing bacterial resistance rates might be reduced if viral and bacterial lower respiratory tract infections (LRTI) could be differentiated clinically. Whether this is possible is often doubted but has rarely been studied in general practice.

STUDY DESIGN AND SETTING

This was an observational cohort study in 15 general practice surgeries in the Netherlands.

RESULTS

Etiologic diagnoses were obtained in 112 of 234 patients with complete data (48%). Viral pathogens were found as often as bacterial pathogens. Haemophilus (para-) influenzae was most frequently found. None of the symptoms and signs correlated statistically significantly with viral or bacterial LRTI. Erythrocyte sedimentation rate >50 (odds ratio [OR] 2.3-3.3) and C-reactive protein (CRP) >20 (OR 2.1-4.6) were independent predictors for viral LRTI and bacterial LRTI when compared with microbiologically unexplained LRTI.

CONCLUSION

Extensive history-taking and physical examination did not provide items that predict viral or bacterial LRTI in adult patients in daily general practice. We could not confirm CRP to differentiate between viral and bacterial LRTI.

Antibiotic resistance of faecal Escherichia coli from healthy volunteers from eight developing countries

OBJECTIVES

To determine the prevalence of antibiotic-resistant faecal Escherichia coli from adult volunteers from urban (U) areas in Kenya, Mexico, Peru and the Philippines, and non-urban (NU) locations in Curacao, Mexico, Venezuela, Ghana, Zimbabwe and the Philippines.

METHODS

Faecal samples of adult volunteers (n=1290) were analysed in one laboratory for the presence of antimicrobial-resistant E. coli using Eosin Methylene Blue agar plates containing, respectively, ampicillin, oxytetracycline, cefazolin, ciprofloxacin, gentamicin, chloramphenicol and trimethoprim at breakpoint concentrations.

RESULTS

The mean age of the volunteers was approximately 35 years; most of them were female. Ciprofloxacin resistance was in the range 1%-63%: the highest percentages were found in the urban populations of Asia and South America. In Peru and the Philippines (U and NU), the prevalence of gentamicin resistance was >20%. Cefazolin resistance was the highest in the urban Philippines (25%). Higher prevalences for ampicillin, oxytetracycline and trimethoprim were found for urban areas compared with non-urban ones of Asia, Africa and South America, respectively (P<0.05).

CONCLUSIONS

In the populations studied, antibiotic resistance in faecal E. coli from adult volunteers was emerging for cefazolin, gentamicin and ciprofloxacin and was high for the older drugs ampicillin, oxytetracycline, trimethoprim and chloramphenicol.

Hospitalization, a risk factor for antibiotic-resistant Escherichia coli in the community?

OBJECTIVE

The impact of hospitalization on the prevalence of resistant Escherichia coli in the intestinal flora of patients admitted to the surgical wards of three Dutch university-affiliated hospitals was analysed prospectively.

METHODS

Faecal samples were obtained on admission to the hospital, at the time of discharge, and 1 and 6 months after discharge. All samples were examined for resistance to nine antibiotic agents.

RESULTS

For the total patient population, no significant differences in the prevalence of resistance were observed at the different sampling intervals, except for a significant decrease in cefazolin resistance between the time of discharge and 6 months after discharge (10% to 3%, P < 0.05). This decrease was mainly observed in patients from the university hospital Maastricht (azM), in which a significant decrease from 17% to 6% was detected (P < 0.05). Moreover, despite dissimilarities in patient characteristics and the marked variations in antibiotic use, no significant differences in the prevalence of antibiotic resistance were observed between the three hospitals, except for the overall higher prevalence of cefazolin-resistant E. coli in azM patients (P < 0.05).

CONCLUSION

In this study, hospitalization did not seem to have any substantial effect on the prevalence of antibiotic-resistant E. coli at the different time intervals. However, as our study population consisted of surgical patients with a relatively moderate antibiotic use, and the prevalence of antibiotic resistance was only analysed for faecal E. coli, further investigation should be encouraged, as the understanding of the interaction between different resistance reservoirs is important for directing future intervention studies.

Antibiotic usage and resistance in different regions of the Dutch community

Regional differences of antibiotic use and antibiotic resistance in the fecal indicator bacteria Escherichia coli and enterococci were determined in different cities in the south, west, and north of The Netherlands. In 1999, differences in antibiotic consumption were observed between the different regions: 11.19, 10.84, and 7.16 DDD (defined daily dosage) per 1,000 inhabitants per day, respectively. No significant regional differences were found in the prevalence of antibiotic resistance for both E. coli and enterococci. However, the differences in antibiotic consumption observed might lead to changes in antibiotic resistance in the near future. Surveillance of antibiotic use and antibiotic resistance is strongly recommended to control the development of antibiotic resistance because it provides epidemiological data to set up and control antibiotic guidelines.

Influence of population density on antibiotic resistance

Antibiotic consumption and population density as a measure of crowding in the community were related to the prevalence of antibiotic resistance of three cities in three different countries: St Johns in Newfoundland (Canada), Athens in Greece and Groningen in The Netherlands. Antibiotic consumption was expressed in DDD (defined daily dose), as DID (DDD/1000 inhabitants/day) and as DSD (DDD/km(2)). The prevalence of antibiotic-resistant Escherichia coli and enterococci was determined in faecal samples of healthy volunteers. In both Newfoundland (28 DID) and Greece (29 DID) the overall consumption of antibiotics was more than three times higher compared with that of The Netherlands (9 DID). The lowest prevalence of resistant E. coli against the majority of antibiotics tested was found for the samples from Newfoundland and was significant (P < 0.05) for cefazolin, oxytetracycline and trimethoprim. A poor correlation between the number of DID and the prevalence of resistance was observed [the Pearson correlation coefficient (Pcc) ranged between -0.93 and 0.87]. However, when population density was taken into consideration and antibiotic consumption was expressed in DSD, a strong correlation was observed (and Pcc ranged between 0.86 and 1.00). This study suggests that population density is an important factor in the development of antibiotic resistance and warrants special attention as a factor in resistance epidemiology.

Is roxithromycin better than amoxicillin in the treatment of acute lower respiratory tract infections in primary care? A double-blind randomized controlled trial

OBJECTIVE

To assess the efficacy of roxithromycin relative to amoxicillin.

STUDY DESIGN

We conducted a double-blind randomized controlled trial of oral 500 mg amoxicillin 3 times per day vs oral 300 mg roxithromycin once a day for 10 days.

POPULATION

We included 196 adults who had presented to a general practitioner with lower respiratory tract infection (LRTI) and, in the physician's opinion, needed antibiotic treatment.

OUTCOMES MEASURED

We measured clinical response after 10 and 28 days, defined in 4 ways: (1) decrease in LRTI symptoms; (2) complete absence of symptoms; (3) decrease in signs; and (4) complete absence of signs. Self-reported response included the decrease in symptoms and the time until resumption of impaired or abandoned daily activities on days 1 through 10, 21, and 27.

RESULTS

Clinical cure rates after the completion of antibiotic treatment (10 days) were not significantly different for the 2 groups. After 28 days, the roxithromycin group showed no increase in cure rate as evidenced by the decrease in symptoms, indicating a significantly lower cure rate. However, this difference did not alter physicians' overall conclusion after complete follow-up that 90% of patients, regardless of age, had been effectively treated with either amoxicillin or roxithromycin.

CONCLUSIONS

The surplus value of roxithromycin was not confirmed. Amoxicillin remains a reliable first-choice antibiotic in the treatment of LRTI in general practice.

Antibiotic resistance of faecal enterococci in poultry, poultry farmers and poultry slaughterers

The prevalence of resistance in enterococci to antibiotics, commonly used for therapy in poultry or as antimicrobial growth promoters (AMGPs), was determined in faecal samples of two chicken populations: broilers in which antibiotic and AMGP use is common and laying-hens with a low antibiotic usage. In addition faecal samples were examined from three human populations: broiler farmers, laying-hen farmers and poultry slaughterers. MICs of an extended panel of antibiotics for a randomly chosen gentamicin- or vancomycin-resistant enterococcal isolate from each faecal specimen were also determined. The prevalence of resistance for all antibiotics tested was higher in broilers than in laying-hens. Resistance in faecal enterococci of broiler farmers was for nearly all antibiotics higher than those observed in laying-hen farmers and poultry slaughterers. The overall resistance in broilers was correlated with the resistance in broiler farmers and in poultry slaughterers. No correlation between the results obtained in the laying-hens with any of the other populations was found. The 27 gentamicin-resistant isolates all showed high-level resistance to gentamicin and two of these isolates, both Enterococcus faecium, were resistant to all antibiotics tested, except vancomycin. The 73 vancomycin-resistant enterococci (VRE) isolated from the five populations belonged to four different species and in all isolates the vanA gene cluster was detected by blot hybridization. The pulsed-field gel electrophoresis (PFGE) patterns of these vancomycin-resistant enterococci were quite heterogeneous, but Enterococcus hirae isolates with the same or a closely related PFGE pattern were isolated at two farms from the broiler farmer and from broilers. Molecular characterization of vanA-containing transposons of these isolates showed that similar transposon types, predominantly found in poultry, were present. Moreover, similar vanA elements were not only found in isolates with the same PFGE pattern but also in other VRE isolated from both humans and chickens. The results of this study suggest transmission of resistance in enterococci from animals to man. For VRE this might be clonal transmission of animal strains, but transposon transfer seems to occur more commonly.

Effects of flavophospholipol on resistance in fecal Escherichia coli and enterococci of fattening pigs

A "plasmid-curing effect" of multiresistant Escherichia coli by flavophospholipol, an antibiotic used as an antimicrobial growth promoter (AMGP) in animal feeds, has been reported to occur in vitro and in vivo under experimental conditions. In this study, the effect of flavophospholipol under field conditions was studied. The prevalence and degree (proportion of resistant strains to the total numbers present per gram of feces) of resistance of indicator bacteria, E. coli and enterococci, was determined in fecal samples from three groups of pigs that were fed a commercial finisher feed without any AMGP. Group A was the negative control group without any AMGP, group B received the same feed with 9 mg of flavophospholipol/kg of feed (study group), and group C received the same feed with 15 mg of avoparcin/kg (positive control). Fecal samples from each pig were collected at the start and at the end of the study and assessed for the prevalence and degree of resistance against antibiotics commonly used either for therapy in pig medicine or as an AMGP. Before the start of the study, all pigs were colonized with multiresistant E. coli by mixing three resistant pig isolates through their feed after disturbance of the colonization resistance of the intestinal flora by a 3-day course of lincomycin and spectinomycin. At the end of the study, the overall prevalence and degree of resistance of E. coli in the fecal flora had increased significantly in groups A and C but remained at the same level as at the start of the study in group B. The prevalence of vancomycin resistance was 44 and 41% in groups A and B, respectively, but only very low numbers of vancomycin-resistant enterococci (VRE) per gram of feces were found. In the avoparcin-fed group, the prevalence was 72%, and in 57% of the samples, more than 50% of all enterococci present were vancomycin resistant. The prevalence of resistant Enterococcus faecalis increased only in the flavophospholipol-exposed group, from 23% before the start of the study to 43% at the end of the study. It was concluded that flavophospholipol effectively suppressed the augmentation and dissemination of multiresistant E. coli in the intestinal flora of fattening pigs. Avoparcin use strongly selected for VRE carriage and excretion. Therefore, as neither flavophospholipol nor any related molecule is used therapeutically, no cross-resistance with therapeutic antibiotics exists and no transmissible resistance has been shown; the major decrease in resistance in intestinal E. coli of flavophospholipol-fed animals seemed to outweigh the small increase in the risk of transfer of flavophospholipol-resistant E. faecalis from animals to humans via the food chain.

Infectious complications and antibiotic use in renal transplant recipients during a 1-year follow-up

OBJECTIVE

To evaluate infectious complications and antibiotic use in 192 renal transplant recipients.

METHODS

Infectious complications and antibiotic use were monitored in all patients receiving renal transplantation at our center from 1992 to 1997. Risk factors for infectious complications were evaluated. Transplants and patient survival were monitored. The follow-up period was 1 year.

RESULTS

One-hundred and ninety-two patients received renal transplants during the study period. The mean duration of urethral catheterisation after transplantation was 10.5 days (SD = 5). Seventy-one per cent (n = 137) of patients had at least one infectious episode. In all, 284 infectious episodes were monitored. The most frequent infections were: urinary tract infections 61%, respiratory tract infections 8%, intra-abdominal infections 7%, and cytomegalovirus infection 8%. Escherichia coli and Enterococcus faecalis were the most frequently isolated microorganisms. Seventy-four per cent (n = 142) of patients received 314 antimicrobial courses (284 for therapy, and 30 for prophylaxis). Female gender and duration of urethral catheterisation were risk factors for urinary tract infection. Cytomegalovirus reactivation was associated with acute graft rejection and additional immunosuppressive therapy. Overall mortality was 4%. Infection-related mortality was 2.6%. Mortality was associated with Enterobacteriaceae in three patients, with Pseudomonas aeroginosa in one patient and with Enterococcus faecalis in one patient.

CONCLUSIONS

The incidence of infectious complications remains high in renal transplant recipients. Most cases of mortality were associated with infections. Early removal of the urethral catheter to reduce the risk of urinary tract infections is recommended.

Prevalence of macrolide resistance genes in clinical isolates of the Streptococcus anginosus ("S. milleri") group

Twenty-two unrelated erythromycin-resistant anginosus group strains (3.2% resistance rate) were assessed for mechanisms of resistance. Streptococcus anginosus accounted for 16 of the 22 isolates. Fifteen isolates harbored the erm(B) gene. The erm(TR) and the mef(E) genes were carried by two isolates each. In three isolates, none of these resistance genes was detected by PCR.

Prevention of ventilator-associated pneumonia by oral decontamination: a prospective, randomized, double-blind, placebo-controlled study

Colonization of the intestinal tract has been assumed to be important in the pathogenesis of ventilator-associated pneumonia (VAP), but relative impacts of oropharyngeal, gastric, or intestinal colonization have not been elucidated. Our aim was to prevent VAP by modulation of oropharyngeal colonization, without influencing gastric and intestinal colonization and without systemic prophylaxis. In a prospective, randomized, placebo-controlled, double-blind study, 87 patients received topical antimicrobial prophylaxis (gentamicin/ colistin/vancomycin 2% in Orabase, every 6 h) in the oropharynx and 139 patients, divided over two control groups, received placebo (78 patients were studied in the presence of patients receiving topical prophylaxis [control group A] and 61 patients were studied in an intensive care unit where no topical prophylaxis was used [control group B]). Baseline characteristics were comparable in all three groups. Topical prophylaxis eradicated colonization present on admission in oropharynx (75% in study group versus 0% in control group A [p < 0.00001] and 9% in control group B patients [p < 0.00001]) and in trachea (52% versus 22% in A [p = 0.03] and 7% in B [p = 0.004]). Moreover, topical prophylaxis prevented acquired oropharyngeal colonization (10% versus 59% in A [p < 0.00001] and 63% in B [p < 0.00001]). Colonization rates in stomach and intestine were not affected. Incidences of VAP were 10% in study patients, 31% in Group A, and 23% in Group B patients (p = 0.001 and p = 0.04, respectively). This was not associated with shorter durations of ventilation or ICU stay or better survival. Oropharyngeal colonization is of paramount importance in the pathogenesis of VAP, and a targeted approach to prevent colonization at this site is a very effective method of infection prevention.

KEYWORDS

cross infection, prevention and control; respiration, artificial, adverse effects; antibiotics, administration and dosage infection control methods; pneumonia, etiology, prevention and control; intubation, intratracheal, adverse effects

Antibiotic resistance of faecal Escherichia coli in poultry, poultry farmers and poultry slaughterers

The percentage of faecal samples containing resistant Echerichia coli and the proportion of resistant faecal E. coli were determined in three poultry populations: broilers and turkeys commonly given antibiotics, and laying hens treated with antibiotics relatively infrequently. Faecal samples of five human populations were also examined: turkey farmers, broiler farmers, laying-hen farmers, broiler slaughterers and turkey slaughterers. The MICs of antibiotics commonly used in poultry medicine were also determined. Ciprofloxacin-resistant isolates from these eight populations and from turkey meat were genotyped by pulsed-field gel electrophoresis (PFGE) after SmaI digestion. The proportion of samples containing resistant E. coli and the percentages of resistant E. coli were significantly higher in turkeys and broilers than in the laying-hen population. Resistance to nearly all antibiotics in faecal E. coli of turkey and broiler farmers, and of turkey and broiler slaughterers, was higher than in laying-hen farmers. Multiresistant isolates were common in turkey and broiler farmers but absent in laying-hen farmers. The same resistance patterns were found in turkeys, turkey farmers and turkey slaughterers and in broiler, broiler farmers and broiler slaughterers. The PFGE patterns of the isolates from the eight populations were quite heterogeneous, but E. coli with an identical PFGE pattern were isolated at two farms from a turkey and the farmer, and also from a broiler and a broiler farmer from different farms. Moreover, three E. coli isolates from turkey meat were identical to faecal isolates from turkeys. The results of this study strongly indicate that transmission of resistant clones and resistance plasmids of E. coli from poultry to humans commonly occurs.

[Optimizing antibiotics policy in the Netherlands. V. SWAB guidelines for perioperative antibiotic prophylaxis. Foundation Antibiotics Policy Team]

The Stichting Werkgroep Antibioticabeleid (SWAB, Foundation Antibiotics Policy Team) has issued guidelines for perioperative antibiotic prophylaxis in Dutch hospitals. Antibiotic prophylaxis is generally recommended for surgical procedures with relatively high postoperative infection rates and those in which consequences of infection are really serious. Studies have revealed that prophylaxis given within two hours before incision is most effective. Short-term, preferably single-dose prophylaxis, is as effective as multiple-dose prophylaxis in most procedures. For reasons of cost effectiveness and prevention of induction of resistance, single-dose prophylaxis is recommended. The antimicrobial agent of choice for perioperative prophylaxis should not be widely used as a therapeutic agent, should be selectively active against micro-organisms most frequently isolated from surgical site infections, and should have a plasma-half-life that makes single-dosing possible for most operations. Therefore cefazoline is an agent that is widely used for perioperative prophylaxis.