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ABSTRACTThe genetic background and the presence of several virulence factors of Staphylococcus aureusisolates from intensive care unit (ICU) patients from 14 hospitals in The Netherlands isolated from 1996 until 2006 were investigated. In total, 936 methicillin-susceptible S. aureus(MSSA) and 7 methicillin-resistant S. aureus(MRSA) isolates were collected. The genetic background was determined by spatyping and multilocus sequence typing (MLST). The virulence determinants Panton-Valentine leukocidin (PVL), toxic shock syndrome toxin 1 (TSST-1), and collagen adhesion (CNA) were detected with real-time PCR assays. On the MRSA isolates, mobile resistance staphylococcal cassette chromosome mec(SCCmec) typing was performed. Among the MSSA isolates, 313 different spatypes were observed. A genetic background common to MRSA clones, e.g., MLST clonal complex 1 (CC1), CC5, CC8, CC22, CC30, and CC45, was observed among 62% of the isolates. The remaining isolates were associated with MSSA-related MLST CCs. MLST CC1, CC25, and CC30 were continuously present, and other MLST CCs fluctuated over time. Two percent of the MSSA isolates harbored PVL, 21% had TSST-1, and 46% were positive for CNA. There were no changes in the prevalence of the virulence factors over time. Four MRSA isolates were typed as ST8-MRSA-IV (where ST is the MLST sequence type and IV is the SCCmectype), two were ST5-MRSA-II, and one was ST228-MRSA-I. All MRSA isolates were PVL, CNA, and TSST-1 negative except for the two ST5-MRSA-II isolates, which were TSST-1 positive. No changes in the S. aureusgenetic background and the prevalence of the virulence factors PVL, CNA, and TSST-1 were observed in ICU patients in The Netherlands over time.

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 ∼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 specificly 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.

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.

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.

ABSTRACTA “plasmid-curing effect” of multiresistant Escherichia coliby 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. coliand 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. coliby 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. coliin 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 faecalisincreased 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. coliin 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. coliof flavophospholipol-fed animals seemed to outweigh the small increase in the risk of transfer of flavophospholipol-resistant E. faecalisfrom animals to humans via the food chain.

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.

Selective digestive decontamination (SDD) is the most extensively studied method for the prevention of infection in patients in intensive care units (ICUs). Despite 27 prospective randomized studies and six meta-analyses, routine use of SDD is still controversial. In this review, we summarize the available scientific information on effectiveness of SDD in ICU patients. The effects of SDD have been studied in different combinations of the concept, using different antibiotics. Comparison of the individual studies, therefore, is difficult. In most studies, SDD resulted in significant reductions in the number of diagnoses of ventilator-associated pneumonia. However, incidences of ventilator-associated pneumonia in control groups ranged from 5% to 85%. Moreover, these reductions in incidences of ventilator-associated pneumonia in individual studies were not associated with improved patient survival, reductions of duration of ventilation or ICU stay, or reductions in antibiotic use. The numbers of patients studied are too small to determine effects on patient survival. Although two meta-analyses suggested a 20% mortality reduction when using the full concept of SDD (topical and systemic prophylaxis) these results should be interpreted with caution. Formal cost-benefit analyses of SDD have not been performed. SDD is associated with the selection of microorganisms that are intrinsically resistant to the antibiotics used. However, the studies are too small and too short to investigate whether SDD will lead to development of antibiotic resistance. As long as the benefits of SDD (better patient survival, reduction in antibiotic use or improved cost-effectiveness) have not been firmly established, the routine use of SDD for mechanically ventilated patients is not advised.

The prevalence and degree of antibiotic resistance of faecal indicator bacteria, Escherichia coli and enteroccoci, were determined in 1321 faecal samples collected from pigs at five abattoirs in The Netherlands and in 100 samples from Swedish pigs. In the Dutch samples a high prevalence of resistance was observed in E. coli for three commonly used antibiotics in pig medicine, amoxycillin (70-94%), oxytetracycline (78-98%) and trimethoprim (62-96%). Also, the prevalence for chloramphenicol (55-67%) and neomycin (38-67%) was relatively high. For the other compounds tested the prevalence was less than 10%. The percentage of samples with a high degree of resistant E. coli showed the same tendency in all Dutch abattoirs although significant differences between the abattoirs were observed. The percentage of Swedish samples with a high degree of resistant E. coli was significantly lower for all antibiotics except nitrofurantoin, gentamicin, flumequin and ciprofloxacin. All enterococci were susceptible to amoxycillin and high-level resistance to gentamicin was observed in 4-6% of the Dutch samples. A high prevalence of resistance and a high degree of resistance was found for erythromycin and oxytetracycline. The prevalence of resistance to dalfopristin-quinupristin ranged from 6 to 8% and for vancomycin from 24 to 46%. Significant differences between the abattoirs were found for all compounds tested except amoxycillin. In the Swedish population both the prevalence and degree of resistance in enterococci were significantly lower except for amoxycillin and gentamicin. This point prevalence study showed that the prevalence and degree of antibiotic resistance in indicator bacteria, E. coli and enterococci, in faecal samples from pigs differed between two countries and reflected differences in antibiotic usage in pigs. To analyse the differences observed between the slaughterhouses, additional information about the farms of origin and antibiotic consumption is necessary.

The antibiotic resistance patterns of gram-negative bacteria isolated from nursing home patients between 1983 and 1997 were analysed. Escherichia coli was the most prevalent isolate (48%) followed by Proteus spp. (26%) and other Enterobacteriaceae (20%). During the study period, the susceptibility of E. coli decreased for co-trimoxazole (79% to 62%), increased for nitrofurantoin (79% to 91%) and remained unchanged for amoxycillin (41%). Susceptibility to norfloxacin, available from 1990, decreased from 87% to 71%. Similar trends were observed when the susceptibilities of all gram-negative urinary pathogens were combined. The changes in susceptibility can probably be attributed to the empirical prescribing practices in the nursing homes studied.

Abstract Background Ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa is usually preceded by colonisation of the respiratory tract. During outbreaks, colonisation with P aeruginosa is mainly derived from exogenous sources. The relative importance of different pathways of colonisation of P aeruginosa has rarely been determined in non-epidemic settings. Methods In order to determine the importance of exogenous colonisation, all isolates of P aeruginosa obtained by surveillance and clinical cultures from two identical intensive care units (ICUs) were genotyped with pulsed field gel electrophoresis. Results A total of 100 patients were studied, 44 in ICU 1 and 56 in ICU 2. Twenty three patients were colonised with P aeruginosa , seven at the start of the study or on admission and 16 of the remaining 93 patients became colonised during the study. Eight patients developed VAP due to P aeruginosa . The incidence of respiratory tract colonisation and VAP with P aeruginosa in our ICU was similar to that before and after the study period, and therefore represents an endemic situation. Genotyping of 118 isolates yielded 11 strain types: eight in one patient each, two in three patients each, and one type in eight patients. Based on chronological evaluation and genotypical identity of isolates, eight cases of cross-colonisation were identified. Eight (50%) of 16 episodes of acquired colonisation and two (25%) of eight cases of VAP due to P aeruginosa seemed to be the result of cross-colonisation. Conclusions Even in non-epidemic settings cross-colonisation seems to play an important part in the epidemiology of colonisation and infection with P aeruginosa .

Objective: To test the accuracy of colour-scaled indicator papers to measure pH values and to study the correlation between this method of measuring gastric juice pH once daily and 24-h continuous intragastric pH monitoring in intensive care patients. Design: The accuracy of indicator papers was tested in the laboratory using colourless solutions and aspirated gastric juice and was then verified with a laboratory pH meter. Continuous intragastric pH monitoring was performed in mechanically ventilated ICU patients. Percentages of time with a pH value <3.0 and median pH values by 24-h continuous intragastric pH monitoring were compared to pH values measured once daily with indicator paper. Setting: A mixed ICU. Patients: A total of 150 measurements were taken by continuous pH monitoring in 91 mechanically ventilated ICU patients. Measurements and results: The correlation between the pH measured with the indicator paper and subsequently verified with a laboratory pH meter in colourless solutions was 0.96 [regression coefficient (RC) 0.98, 95% confidence interval (CI) 0.91–1.05]. Measured in gastric juice it was 0.95 (RC 0.95, 95% CI 0.88–1.01). The correlation between median pH values, determined with 24-h continuous intragastric pH monitoring, and values measured with indicator papers was 0.39 (RC 0.43, 95% CI 0.26–0.59). The mean difference in pH, as determined by the analysis of Bland and Altman [22], was 0.9 with a SD of 4.7. The correlation between the percentage of time with pH <3.0, as obtained with continuous registration, and median gastric pH values (also obtained with continuous registration) was -0.94 (RC -0.06, 95% CI -0.06–-0.05); the correlation between the time and gastric pH values (measured with indicator paper) was -0.40 (RC -0.02, 95% CI -0.03–-0.02). Conclusion: The colour-scaled indicator paper is an accurate method of measuring pH values, but there is a poor correlation between gastric pH values measured once daily and a total measurement derived from 24-h continuous intragastric pH monitoring. Changes in intragastric pH values cannot be accurately studied when measuring acidity once daily. The influence of various treatment regimens on intragastric acidity in relation to the development of gastric colonization and nosocomial pneumonia should be investigated either with continuous intragastric monitoring or with frequent measurements in aspirated gastric juice.

The occurrence of class II restriction endonucleases (enzymes that both recognize and cleave a specific nucleotide sequence in deoxyribonucleic acid [DNA] in Staphylococcus aureus has been investigated by analysis of crude extracts obtained from different propagating strains of the International Phage Typing System. Of the four main groups of strains in the International System, only extracts of group II strains were found to contain class II restriction endonucleases. The identical cleavage patterns obtained by incubation of different DNAs with cell extracts of group II strains suggest that these enzymes all recognize and cleave the same nucleotide sequence. This recognition site has been determined to be 5'-G-A-T-C-3'-3'-C-T-A-G-5' for the prototype of these enzymes, Sau3AI (J. S. Sussenbach et al., Nucleic Acids Res. 3:3192-3202, 1976). Evidence is presented that the classification of group II strains is based on restriction modification and is correlated with the presence of a class II restriction enoduclease that recognizes and cleaves the above sequence.

Faecal samples were collected from healthy volunteers in two regions in Venezuela, the village of Grulla (n=195) and the city of Mérida (n=181), and analysed for the prevalence of antibiotic resistant faecalEscherichia colias well as the antibiotic susceptibility of the strains isolated. The highest prevalences of resistance were observed for amoxicillin, oxytetracycline, sulfamethoxazole and trimethoprim. The percentages found for Grulla were 46, 38, 44 and 30%, respectively; for Mérida 39, 65, 56 and 36%, respectively. In Mérida, a significantly higher prevalence of resistance for oxytetracycline was found (P<0.05). Significant differences in the distribution of the MIC values between Grulla and Mérida were observed for amoxicillin, chloramphenicol and oxytetracycline (P<0.05). In Grulla, the most frequent pattern was resistance to amoxicillin only and in Mérida to oxytetracycline only. Amoxicillin resistance was due to production of TEM1 β-lactamase.

Seven laboratories, including a reference laboratory, tested the susceptibility of Moraxella catarrhalis, Streptococcus pneumoniae and Haemophilus influenzae strains to ciprofloxacin, clarithromycin, co-amoxiclav and sparfloxacin with the Etest. A total of 976 strains were collected. The results with ciprofloxacin and sparfloxacin were consistent for all laboratories, while those with clarithromycin and co-amoxiclav were not. The agreement between Etest MICs and broth microdilution was: ciprofloxacin and sparfloxacin, >95%; clarithromycin for all species, 71-85%; co-amoxiclav for H. influenzae, 31%. MIC90 values (broth dilution, mg/L) for M. catarrhalis, S. pneumoniae and H. influenzae were: sparfloxacin, 0.06, 0.5, 0.03; ciprofloxacin, 0.12, 2.0, 0.03; co-amoxiclav, 0.25, 0.25, 0.25; clarithromycin 0.25, 0.25 and 16.

We studied the influences of antimicrobial agents on the colonization of the respiratory tract and infection with Enterococcus faecalis in intensive care unit (ICU) patients receiving mechanical respiration for at least 3 days. In a matched-cohort analysis, patients receiving topical antimicrobial prophylaxis (TAP) of the oropharynx and stomach with antimicrobial agents not treating E. faecalis were compared with patients not receiving TAP. Patients were matched with controls on the basis of their duration in the ICU, their use of systemic antibiotics treating and not treating E. faecalis, the administration of TAP, their APACHE II score, and surgical procedures they had undergone. In all, 276 patients were analyzed. The colonization of the oropharynx and/or trachea by E. faecalis at admission was demonstrated for 43 patients (16%). Twenty patients (9%) acquired tracheal colonization and 91 patients (40%) acquired oropharyngeal colonization with E. faecalis. In the matched-cohort analysis, 43 patients receiving TAP were matched in two controls each. TAP patients more frequently acquired tracheal colonization (15 of 43 versus 2 of 86 patients, P < 0.00001) and infections with E. faecalis (6 of 43 versus 1 of 86 patients, P < 0.01). The use of topical antibiotics and treating E. faecalis increased the risk for colonization and infection with E. faecalis.

Summary This paper reports a case of fatal meningitis caused byFusobacterium necrophorum subsp.necrophorum in a previously healthy five-year-old child. The organism was isolated in pure culture from the cerebrospinal fluid and from intracranial pus obtained at autopsy. The role ofF. necrophorum in the development of meningitis is reaffirmed and its isolation and identification are discussed. The clinical presentation of the present case resembles the previously published reports and highlights the poor prognosis in spite of appropriate antibiotic treatment.

A semiquantitative serological test (G.A.P. test; Bio-Rad) to diagnose Helicobacter (Campylobacter) pylori-associated gastritis has recently become commercially available. This test was evaluated with sera from 72 dyspeptic patients with known H. pylori status. When the instructions provided by the manufacturer were applied strictly, the sensitivity of the test was only 32.7%. With a slight modification of the instructions, the performance characteristics were still unsatisfactory (specificity, 43.5%). When a new cutoff value was determined by a receiver operating curve, the quality of the test (positive predictive value, 95.6%; negative predictive value, 77.8%) was slightly lower than that of a noncommercial enzyme-linked immunosorbent assay (positive predictive value, 95.7%; negative predictive value, 84.0%). It is concluded that the Bio-Rad G.A.P. test has low diagnostic yield, and it is stressed that commercial tests should be evaluated extensively before being applied in daily practice.

Three commercial available tobramycin assays, the fluorescent immunoassay (AMES), the Diagnostic Products Corp. radioimmunoassay, and the Nuclear Medical System radioimmunoassay, were compared with the microbiological assay and the chemical assay involving high-performance liquid chromatography. The results obtained with each assay were evaluated in terms of usefulness, reproducibility, and cost-effectiveness.

Successive transfer of three clinical isolates ofPseudomonas aeruginosa in liquid medium containing serial dilutions of several beta-lactam antibiotics was used to isolate resistant variants. The alpha-carboxy-penicillins (carbenicillin and ticarcillin), the acylureidopenicillins (piperacillin and azlocillin) and cephalosporins (moxalactam, cefoperazone, cefsulodin and ceftazidime) were used as the selective antibiotics. Resistant variants were isolated from two of the three strains (strains 27 and 45), using an inoculum size of 104–105 CFU/ml, which showed a mean 5 to 8-fold increase in MIC for most of the selected antibiotics. The 27-carbenicillin and 27-cefsulodin resistant variants showed beta-lactamase production similar to that of the parent. However, alterations were found in outer-membrane proteins and lipopolysaccharides. With azlocillin, moxalactam and ceftazidime as the selective antibiotics, resistant variants were isolated from strains 27 and 45 which showed a stable increased constitutive beta-lactamase production. From the third strain, 9150, the only variants isolated showed a two dilution-step increase in MIC to the antibiotics tested. The betalactamase production, outer-membrane proteins and lipopolysaccharides of these variants were similar to those of the parent.

A collection of 518 ‘Streptococcus milleri’ strains was tested for the presence of hydrolytic enzymes, and the results were related to the clinical significance of the strains. Ribonuclease activity was equally distributed among the three species while hyaluronidase activity was linked toStreptococcus intermedius andStreptococcus constellatus. Both enzymes were not significantly associated with infection-related strains. Deoxyribonuclease and chondroitin sulfatase activity tended to be present more frequently inStreptococcus intermedius andStreptococcus constellatus and was associated with infection-related strains (p<0.001).

Ventilator-associated pneumonia is frequently diagnosed with quantitative cultures of samples obtained by bronchoscopic techniques, a method associated with high costs and potential adverse effects. Quantitative cultures of endotracheal aspirates are easier and cheaper to obtain, and good correlations between the results of this method and those of bronchoscopic methods have been reported. However, the reproducibility of quantitative cultures of endotracheal aspirates has never been determined. We studied the quantitative analysis of endotracheal aspirates from 21 mechanically ventilated patients taken during two study days with 2- and 6-h intervals between samplings. In all, 40 endotracheal aspirates were obtained. For mechanically ventilated patients, the median variation of quantitative culture results was 12.3% (range, 0 to 63%), corresponding to 0.7 log CFU/ml. Furthermore, variation was independent of the interval of time between samplings. Persistence of significant numbers of pathogens in quantitative cultures (> or = 10(5) CFU/ml) of the consecutive endotracheal aspirates occurred in 82% of samples. We conclude that results of quantitative cultures from endotracheal aspirates are reproducible and may be useful in diagnosing ventilator-associated pneumonia.

&lt;it>Objectives&lt;/it>: To determine the prevalence of antibiotic-resistant faecal &lt;it>Escherichia coli&lt;/it> from adult volunteers from urban (U) areas in Kenya, Mexico, Peru and the Philippines, and non-urban (NU) locations in Curaçao, Mexico, Venezuela, Ghana, Zimbabwe and the Philippines. &lt;it>Methods&lt;/it>: Faecal samples of adult volunteers (&lt;it>n&lt;/it>=1290) were analysed in one laboratory for the presence of antimicrobial-resistant &lt;it>E. coli&lt;/it> using Eosin Methylene Blue agar plates containing, respectively, ampicillin, oxytetracycline, cefazolin, ciprofloxacin, gentamicin, chloramphenicol and trimethoprim at breakpoint concentrations. &lt;it>Results&lt;/it>: The mean age of the volunteers was ∼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 (&lt;it>P&lt;/it>&lt;0.05). &lt;it>Conclusions&lt;/it>: In the populations studied, antibiotic resistance in faecal &lt;it>E. coli&lt;/it> from adult volunteers was emerging for cefazolin, gentamicin and ciprofloxacin and was high for the older drugs ampicillin, oxytetracycline, trimethoprim and chloramphenicol.

&lt;it>Objective&lt;/it>: The impact of hospitalization on the prevalence of resistant &lt;it>Escherichia coli&lt;/it> in the intestinal flora of patients admitted to the surgical wards of three Dutch university-affiliated hospitals was analysed prospectively. &lt;it>Methods&lt;/it>: 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. &lt;it>Results&lt;/it>: 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&percnt; to 3&percnt;, &lt;it>P&lt;/it> &lt; 0.05). This decrease was mainly observed in patients from the university hospital Maastricht (azM), in which a significant decrease from 17&percnt; to 6&percnt; was detected (&lt;it>P&lt;/it> &lt; 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 &lt;it>E. coli&lt;/it> in azM patients (&lt;it>P&lt;/it> &lt; 0.05). &lt;it>Conclusion&lt;/it>: In this study, hospitalization did not seem to have any substantial effect on the prevalence of antibiotic-resistant &lt;it>E. coli&lt;/it> 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 &lt;it>E. coli&lt;/it>, further investigation should be encouraged, as the understanding of the interaction between different resistance reservoirs is important for directing future intervention studies.

The in-vitro activity of Sch 34343, a derivative of Sch 29482, was assessed and compared with that of other β-lactam antibiotics. Nearly all Enterobacteriaceae, including ampicillin-resistant strains (MIC ≥256 mg/1) were inhibited at concentrations ranging from 0.125–8 mg/1. The geometric mean MIC values varied from 0.25 mg/1 to 2.4 mg/1 for Klebsiella and Serratia spp., respectively. Sch 34343 did not inhibit Pseudomonas aeruginosa. The antibacterial activity was minimally altered by changes of medium or inoculum size. The results suggest high stability against plasmid- and chromosomally-mediated β-lactamases. However, crude extracts of four Pseudomonas strains did hydrolyse Sch 34343. In addition to the high antibacterial activity and the β-lactamase stability, Sch 34343 markedly inhibited most plasmid- and chromosomally-mediated β-lactamases, with the exception of PSE-1 and PSE-4.