Characterization of the molecular mechanisms of quinolone resistance in Yersinia enterocolitica O:3 clinical isolates

OBJECTIVES

The aim of this study was to determine the roles of mutations in the gyrA and parC genes and the overexpression of efflux pump(s) as mechanisms of resistance to quinolones. Forty-five Yersinia enterocolitica O:3 clinical isolates (41 nalidixic acid-resistant, three nalidixic acid-susceptible and one nalidixic acid-resistant strain obtained in vitro) were analysed.

RESULTS

All the nalidixic acid-resistant strains showed mutations in the gyrA gene and none in the parC gene. The presence of the inhibitor produced decreases in the MIC values of nalidixic acid by two to six serial dilution steps in 37 of the 41 nalidixic acid-resistant strains. Meanwhile, the MIC value of ciprofloxacin was affected in two strains whose values diminished three serial dilution steps. The nalidixic acid-resistant mutant obtained in vitro was also affected by the inhibitor decreasing the MIC value of nalidixic acid three serial dilutions steps whereas the MICs for the nalidixic acid-susceptible strains were not affected.

CONCLUSIONS

Our results show that the high level of resistance to nalidixic acid is likely due to an overexpression of an efflux pump plus a mutation in the gyrA gene, whereas decreased susceptibility to ciprofloxacin is only associated with the presence of a mutation in the gyrA gene.

Triflusal vs aspirin for prevention of cerebral infarction

BACKGROUND

Triflusal is an antiplatelet agent that has shown clinical advantages when compared with aspirin in the secondary prevention of vascular events. TAPIRSS (Triflusal versus Aspirin for Prevention of Infarction: a Randomized Stroke Study) explored the efficacy and safety of triflusal in the secondary prevention of stroke in a Latin American homogeneous population with the ultimate aim of preparing for a larger trial in the same setting.

METHODS

A double-blind, multicenter, randomized, pilot trial was conducted in Buenos Aires, Argentina, from October 1996 to November 1999. The study sample was 431 patients, randomized to receive aspirin 325 mg daily or triflusal 600 mg daily for a mean of 586 days. All patients had experienced either an ischemic stroke or TIA within 6 months from enrollment. Data from 429 patients were analyzed.

RESULTS

No differences were observed in the primary endpoint that combined the incidence of vascular death, cerebral ischemic infarction, nonfatal myocardial infarction, or major hemorrhage (aspirin 13.9%, triflusal 12.7%; odds ratio [OR] 1.11, 95% CI 0.64 to 1.94) or in the individual analysis of each component of the primary endpoint. In a post hoc analysis, the overall incidence of major and minor hemorrhagic events was significantly lower in triflusal-treated patients (aspirin 8.3%, triflusal 2.8%; OR 3.13, 95% CI 1.22 to 8.06).

CONCLUSIONS

This pilot trial has not found differences between triflusal and aspirin in the prevention of vascular complications after TIA or ischemic stroke, although given the wide CI, potentially important group differences could not be ruled out. Triflusal may be associated with a lower risk of hemorrhagic complications. A larger, prospective clinical trial is necessary to verify these results.

The clover and heart signs in vertebral scintigraphic images are highly specific of Paget's disease of bone

BACKGROUND

Bone scintigraphy used as a diagnostic technique frequently yields non-specific intense uptake by vertebrae. Bone biopsy may therefore be required to establish a diagnosis in cases of Paget's disease of bone. The aim of the study was to ascertain the sensitivity and specificity of two new images-heart sign and clover sign-in Paget's disease of bone.

METHODS

Two expert rheumatologists analyzed 294 bone scintigraphies of patients with vertebral involvement: 204 without and 90 with Paget's disease. The presence or absence of the clover or heart signs was determined in each scintigraphy. A specificity and sensitivity study was performed with the data obtained. A study of concordance was made between two radiologists blinded to the real diagnosis. Each one analyzed 120 scintigraphies for the presence and absence of the signs: 40 with Paget's disease and clover and/or heart signs (selected from the initial 90 cases), 40 with Paget's disease with neither sign and 40 selected from the pool of 4000 scintigraphies of patients with vertebral involvement, with images easily mistaken for these signs (vertebral collapse, osteoarthritis and bone metastases). Kappa statistics were calculated.

FINDINGS

Sensitivity of both signs for Paget's disease of bone was low: 44% (95% CI 34.0 to 55.3). However, specificity was excellent: 100% (95% CI 98.2 to 100). Inter-radiologist concordance was almost perfect: Kappa 0.86 (95% CI 0.77 to 0.95).

INTERPRETATION

The heart and clover signs are highly specific (probably pathognomonic) of Paget's disease of bone. In cases with doubtful radiologic images, these findings on scintigraphic vertebral images may afford a definitive diagnosis of Paget's disease of bone and thus obviate further confirmatory invasive diagnostic procedures.

Discriminative capacity of calcaneal quantitative ultrasound and of osteoporosis and fracture risk factors in postmenopausal women with osteoporotic fractures

Bone fragility fractures constitute the principal complication of osteoporosis. The identification of individuals at high risk of sustaining osteoporotic fractures is important for implementing preventive measures. The purpose of this study is to analyze the discriminative capacity of a series of osteoporosis and fracture risk factors, and of calcaneal quantitative ultrasound (QUS), in a population of postmenopausal women with a history of osteoporotic fracture. A cross-sectional analysis was made of a cohort of 5195 women aged 65 or older (mean +/- SD: 72.3 +/- 5.4 years) seen in 58 primary care centers in Spain. A total of 1042 women (20.1%) presented with a history of osteoporotic fracture. Most fractures (93%) were non-vertebral. Age-adjusted odds ratios corresponding to each decrease in one standard deviation of the different QUS parameters ranged from 1.47 to 1.55 (P < 0.001) for fractures. The age-adjusted multivariate analysis yielded the following risk factors independently associated with a history of osteoporotic fracture: number of fertile years, a family history of fracture, falls in the previous year, a history of chronic obstructive airway disease, the use of antiarrhythmic drugs, and a low value for any of the QUS parameters. The area under the receiver operating characteristic curve of the best model was 0.656. In summary, a series of easily assessable osteoporotic fracture risk factors has been identified. QUS was shown to discriminate between women with and without a history of fracture, and constitutes a useful tool for assessing fracture risk. Various of the vertebral and hip fracture risk factors frequently cited in North American and British populations showed no discriminative capacity in our series--thus suggesting that such factors may not be fully applicable to our population and/or to the predominant type of fractures included in the present study.

Antibiotic resistance and epidemiological typing of Staphylococcus aureus strains from ovine and rabbit mastitis

Mastitis is a serious problem for sheep and rabbit farms, Staphylococcus aureus being the main causal agent. Fifty strains of S. aureus isolated from sheep and rabbits from farms located in diverse geographical regions of Spain were studied. Their resistance pattern and plasmid profile was related to the pulsotypes obtained by pulsed-field gel electrophoresis (PFGE). The results showed great heterogeneity in staphylococci isolated from sheep, both in pulse-type and plasmid profile. We found in addition, antibiotic-resistant strains and aminoglycoside-modifying enzyme (AGMEs) producer strains. The genotypes corresponding to staphylococci isolated from rabbits were less heterogeneous, although they also could be subdivided by plasmid profile and resistance patterns. Resistance to antibiotics such as methicillin or AGMEs production could indicate possible human origin of the strains or a possible source of resistant strains for human beings.

Evaluation of two miniaturized systems, MicroScan W/A and BBL Crystal E/NF, for identification of clinical isolates of Aeromonas spp

Fifty-two clinical strains and 22 type and reference Aeromonas strains, previously genetically characterized by 16S rRNA gene restriction fragment length polymorphism, were identified in parallel with the MicroScan Walk/Away and BBL Crystal Enteric/Nonfermenter systems. The former identified only 14.8% of the isolates correctly, and the latter identified only 20.3% correctly, which indicates that neither of these systems is useful for this purpose.

[Different antibiotic resistance mechanisms associated with integrons in clinical isolates of Salmonella typhimurium]

Antibiotic resistance in clinical isolates of Salmonella typhimurium has steadily risen in recent years. Some of the resistance genes may be carried into integrons. In this study, integrons, both from 10 epidemiologically related and unrelated S. typhimurium clinical isolates, were characterized, showing that epidemiologically different strains can carry the same integron, and that epidemiologically related strain can carry different integrons. Among the resistance genes detected in this study were genes encoding b-lactamases (bla(oxa-30) in two strains, and bla(pse-1) in five strains, one of which was carrying this cassette in two different integrons); aminoglycoside-modifying enzymes (aadA2 in four strains, one of which was carrying this cassette in two different integrons, and aadA1 in six strains); as well dihydrofolate reductases (dfrAI in three strains).

Community-acquired febrile urinary tract infection in diabetics could deserve a different management: a case-control study

OBJECTIVE

To investigate if there are relevant differences in clinical, microbiological and outcome characteristics of community-acquired febrile urinary tract infection (UTI) between diabetic and nondiabetic patients.

DESIGN

A prospectively matched case-control study.

SETTING

An 800-bed tertiary care university-affiliated hospital.

SUBJECTS

A total of 108 patients (54 diabetic and 54 nondiabetic patients matched by age and gender) admitted between January 1996 and September 1999 with febrile UTI.

METHODS

Clinical, analytical, microbiological and outcome variables were analysed by means of McNemar test (categorical) or Wilcoxon matched pairs signed rank test (continuous).

RESULTS

Mean age (SD) in both groups was 67.9 (14.4) years. In comparison with controls, diabetic patients were more likely to have fever without localizing symptoms (27% vs. 9%, P </= 0.0001), diminished consciousness level at admission (25% vs. 10%, P = 0.03), aetiological microorganism different from Escherichia coli (17% vs. 0, P = 0.0004), and quinolone-resistant bacteria (17% vs. 3.7%, P = 0.07). Duration of fever after the onset of treatment was 1.75 (1) days in diabetics and 1.5 (1.1) days in nondiabetics (P = 0.17). However, diabetic patients had a longer hospitalization [5.2 (3.3) days] than nondiabetics [3.9 (2.6) days, P = 0.006].

CONCLUSIONS

In diabetic patients, febrile UTIs have clinical and microbiological peculiarities that may have diagnostic and therapeutic implications.

Integron-mediated antibiotic multiresistance in Acinetobacter baumannii clinical isolates from Spain

OBJECTIVE

To determine whether non-epidemiologically related, antibiotic-resistant isolates of Acinetobacter baumannii from different geographical origins possess common type 1 integrons.

METHODS

The epidemiologic relationships between seven A. baumannii strains recovered from different Spanish hospitals were established by pulsed-field gel electrophoresis, the presence of integrons being determined by PCR and DNA sequencing.

RESULTS

Integron analysis showed the presence of four different integrons, containing six different known genes (aacC1, aacA4, aadA1, aadB, oxa21 and oxa37) plus an ORF. It was found that the same integron was present in different unrelated strains and that related strains could have different integrons.

CONCLUSION

These results show the potential risk of integron dissemination among different strains of A. baumannii.

Comparison of a high-protein disease-specific enteral formula with a high-protein enteral formula in hyperglycemic critically ill patients

AIMS

To determine whether a specific high-protein enteral formula with a similar caloric percentage of fat and carbohydrates achieves greater control over glycemic levels and reduces insulin requirements in hyperglycemic critically ill patients when compared to a control high-protein enteral formula.

DESIGN

A prospective, randomized, controlled, single-blind trial in two University Hospital Intensive Care Units in Spain.

METHODS

We enrolled 50 patients with diabetes mellitus or stress hyperglycemia with basal glycemia > or =160 mg/dl and indication for enteral nutrition > or =5 days. Patients with severe kidney failure, liver failure or obesity were excluded from the study. In the first 48 h of admission, after randomization, 26 patients received the study diet and 24 patients received the control diet. The variables were monitored for 14 days. The Harris-Benedict formula with a fixed stress factor of 1.2 was used to calculate caloric needs. Insulin was administered by continuous infusion. An intention-to-treat analysis was performed.

RESULTS

On admission, there were no differences between the study and control group in plasma glucose levels (mg/dl) (190.9+/-45 vs 210.3+/-63) and capillary glucose levels (mg/dl) (226.1+/-73 vs 213.8+/-67). After the feeding trial, there were differences between the study and control group in plasma glucose levels (mg/dl) (176.8+/-44 vs 222.8+/-47, P=0.001), capillary glucose levels (mg/dl) (163.1+/-45 vs 216.4+/-56, P=0.001), insulin requirements/day (IU) 8.73 (2.3-27.5) vs 30.2 (21.5-57.1) (P=0.001), insulin/received carbohydrates (UI/g) 0.07 (0.02-0.22) vs 0.18 (0.11-0.35) (P=0.02) and insulin/received carbohydrates/kg 0.98 (0.26-3.59) vs 2.13 (1.44-4.58) (P=0.04). These differences remain in a day-to-day comparison. There were no differences in the analytical tests, or in digestive or infectious complications. Intensive Care Unit length of stay, mechanical ventilation and mortality were similar in both groups.

CONCLUSIONS

Hyperglycemic critically ill patients fed with a high-protein diet with a similar caloric percentage of fat and carbohydrates show a significant reduction in plasma glucose levels, capillary glucose levels and insulin requirements in comparison to patients on a conventional high-protein diet. This better glycemic control do not modify Intensive Care Unit length of stay, infectious complications, mechanical ventilation and mortality.

[Is pre-operative treatment with ursodeoxycholic acid useful in reducing relapses in acute biliary pancreatitis?]

In the present paper, we evaluate the possible reduction in the rate of relapses in acute biliary pancreatitis through treatment with ursodeoxycholic acid (UCA), between the episode of pancreatitis and the moment of cholecystectomy. We studied 72 consecutive first episodes of acute biliary pancreatitis, in patients who had not yet undergone colecistectomy, followed up until surgery. The cases were divided into group A (n=30), treated with ursodeoxycholic acid 10 mg/kg/day, until surgery, and group B or control (n=42). We evaluated the differences between both groups, regarding patient characteristics, pancreatitis severity, characteristics of the lithiasis and delay until surgery. We analysed pancreatitis relapses in both groups, with and without UCA. In the UCA group we compared the duration of treatment between patients with and without pancreatitis relapse. The two groups did not show significant differences regarding any of the studied parameters. We registered 7/30 (23.3%) relapses in UCA group, versus 9/42 (21.4%) relapses in the control group (p = 0.85). In UCA group, treatment duration was similar between relapsed cases: 4.9+/-4.5 months and those without relapse: 4.4+/-1.9 months (p = 0.78). In our experience, the use of UCA until the moment of cholecystectomy does not reduce relapse incidence in patients following the first episode of acute biliary pancreatitis. UCA treatment duration did not seem to be related with the occurrence of pancreatitis relapse.

[Conjunctival infection due to penicillium SP]

CLINICAL CASE

We present a case of conjunctivitis in a diabetic patient in whom not improvement was observed after empiric treatment, and finally developed a conjunctival granuloma. Culture of the conjunctival exudate and histological examination of the conjunctival biopsy confirmed the infection by Penicillium sp. The antifungical treatment (local and systemic) improved signs and symtoms gradually.

DISCUSSION

Penicillium sp is an infrequent cause of conjunctival infection. This diagnosis should be considered when no response after usual therapy to conjunctivitis is obtained and should be confirmed by identification of the fungus in the lesions biopsed and cultured. Succesful management of ocular penicilliosis is achieved with both local and systemic antifungal treatment.

Correlation between the activity of different fluoroquinolones and the presence of mechanisms of quinolone resistance in epidemiologically related and unrelated strains of methicillin-susceptible and -resistant Staphylococcus aureus

OBJECTIVE

To study the activity of five different fluoroquinolones against 22 epidemiologically related and unrelated strains of Staphylococcus aureus (13 methicillin-resistant (MRSA) strains and nine methicillin-susceptible (MSSA) strains) in which the mechanisms of quinolone resistance are also investigated.

METHODS

The MICs of the different fluoroquinolones were determined by the microdilution method, in the presence and absence of reserpine. The quinolone resistance-determining regions of the gyrA, gyrB, grlA and grlB genes were amplified and sequenced to establish the presence of mutations. The molecular epidemiology of the 22 strains was performed by low-frequency restriction analysis of chromosomal DNA with SmaI.

RESULTS

MSSA strains showed lower homology than MRSA strains, in which only two clones were seen. Trovafloxacin showed the best activity against these clinical isolates of S. aureus, since strains carrying one amino acid change in both GyrA and GrlA subunits remained susceptible to this antimicrobial agent. Furthermore, trovafloxacin did not seem to be a substrate for NorA.

CONCLUSION

Trovafloxacin was the most active quinolone tested against S. aureus strains, followed by levofloxacin and sparfloxacin, whereas ciprofloxacin and norfloxacin were the least active quinolones, in both the presence and absence of reserpine. Epidemiologically related S. aureus strains presented different mechanisms of quinolone resistance, suggesting a divergent evolution of the same clone. Finally, 16 S. aureus strains with a ciprofloxacin plus reserpine MIC > or = 1 mg/L already showed a mutation in the grlA gene. This MIC may be useful as a marker of mutation in this gene, contraindicating the use of this quinolone, since a second mutation may develop during treatment.

Digestive anisakiasis: clinical manifestations and diagnosis according to localization

OBJECTIVES

Digestive anisakiasis is a parasitic disease whose clinical manifestations depend on the effect of Anisakis simplex on the digestive tract wall. Larvae are acquired by eating raw or poorly cooked fish. It is estimated that this entity is currently under-diagnosed, although publications are becoming increasingly common. We analyse our series of digestive anisakiasis checking localization and studying its relationship with symptoms and method of diagnosis.

PATIENTS AND METHOD

We review 23 cases of digestive anisakiasis registered between 1989 and 2001, and confirmed by the measurement of specific serum Ig E antibodies. We analyse clinical symptoms and method of diagnosis according to whether localization was gastro-duodenal or intestinal, evaluating whether surgical intervention was needed for a correct diagnosis. The statistical analysis is made using Fisher's test.

RESULTS

23 patients were included between 1989 and 2001, 8 with gastro-duodenal localization and 15 with intestinal localization. All patients with intestinal localization had abdominal pain. Symptoms were less severe for gastro-duodenal cases, and diagnosis was made by clinical suspicion and subsequent gastroscopy, whereas more than a half of intestinal cases required histological examination of a surgical specimen for correct diagnosis. In the remaining half, diagnosis was made by abdominal ultrasonography. We also observed that the need for surgery has decreased with time from 6/6 cases in the 1989-1996 period of time to 2/9 in the 1997-2001 period of time.

CONCLUSIONS

Clinical manifestations of anisakiasis vary depending on localization, symptoms being more severe in intestinal forms. The diagnosis of gastro-duodenal anisakiasis did not need surgery and was based mainly on gastroscopy findings, whereas intestinal forms frequently required histological examination of the surgical specimen. In our hospital, a higher index of clinical suspicion allowed us to diagnose intestinal anisakiasis without examination of surgical specimens in the last years.

Wavelet transform analysis of heart rate variability during myocardial ischaemia

Analysis of heart rate variability (HRV) is a valuable, non-invasive method for quantifying autonomic cardiac control in humans. Frequency-domain analysis of HRV involving myocardial ischaemic episodes should take into account its non-stationary behaviour. The wavelet transform is an alternative tool for the analysis of non-stationary signals. Fourteen patients have been analysed, ranging from 40 to 64 years old and selected from the European Electrocardiographic ST-T Database (ESDB). These records contain 33 ST episodes, according to the notation of the ESDB, with durations of between 40s and 12 min. A method for analysing HRV signals using the wavelet transform was applied to obtain a time-scale representation for very low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands using the orthogonal multiresolution pyramidal algorithm. The design and implementation using fast algorithms included a specially adapted decomposition quadrature mirror filter bank for the frequency bands of interest. Comparing a normality zone against the ischaemic episode in the same record, increases in LF (0.0112 +/- 0.0101 against 0.0175 +/- 0.0208 s2 Hz(-1); p<0.1) and HF (0.0011 +/- 0.0008 against 0.00 17 +/- 0.0020 s2 Hz(-1); p<0.05) were obtained. The possibility of using these indexes to develop an ischaemic-episode classifier was also tested. Results suggest that wavelet analysis provides useful information for the assessment of dynamic changes and patterns of HRV during myocardial ischaemia.

Interaction between the Gln-Arg 192 variants of the paraoxonase gene and oleic acid intake as a determinant of high-density lipoprotein cholesterol and paraoxonase activity

Olive oil, rich in oleic acid, could play a particular beneficial role in the anti-atherogenic effects attributed to the Mediterranean diet. Paraoxonase (PON1) has emerged as the component of high-density lipoproteins (HDL) most likely to explain its ability to attenuate the oxidation of low-density lipoproteins. We hypothesised that oleic acid intake might be associated with changes in PON1-HDL associated particles, and investigated the impact, if any, on this association of the PON1-192 polymorphism, a common polymorphism that strongly modulates PON1 activity. Six hundred and fifty-four men randomly selected from the census were studied. Oleic acid intake was calculated from a 72-h recall questionnaire with specific software. Oleic acid intake groups (low vs. high) were created by stratifying the population according the median value as a cut-point. After adjusting for confounding variables, high oleic acid intake was associated with increased HDL cholesterol levels and PON1 activity only in subjects with the QR and the RR genotypes, respectively. Analyses of the variance showed a statistically significant interaction between PON1-192 genotypes and oleic acid intake for log PON1 activity (P=0.005) and a marginally significant interaction for HDL cholesterol (P=0.066). These results suggest that the beneficial effect of increasing oleic acid intake on HDL and PON1 activity at population level is especially observed in subjects carrying the R allele of the PON1-192 polymorphism.

Identification of a novel metabolite in the degradation of pyrene by Mycobacterium sp. strain AP1: actions of the isolate on two- and three-ring polycyclic aromatic hydrocarbons

Mycobacterium sp. strain AP1 grew with pyrene as a sole source of carbon and energy. The identification of metabolites accumulating during growth suggests that this strain initiates its attack on pyrene by either monooxygenation or dioxygenation at its C-4, C-5 positions to give trans- or cis-4,5-dihydroxy-4,5-dihydropyrene, respectively. Dehydrogenation of the latter, ortho cleavage of the resulting diol to form phenanthrene 4,5-dicarboxylic acid, and subsequent decarboxylation to phenanthrene 4-carboxylic acid lead to degradation of the phenanthrene 4-carboxylic acid via phthalate. A novel metabolite identified as 6,6'-dihydroxy-2,2'-biphenyl dicarboxylic acid demonstrates a new branch in the pathway that involves the cleavage of both central rings of pyrene. In addition to pyrene, strain AP1 utilized hexadecane, phenanthrene, and fluoranthene for growth. Pyrene-grown cells oxidized the methylenic groups of fluorene and acenaphthene and catalyzed the dihydroxylation and ortho cleavage of one of the rings of naphthalene and phenanthrene to give 2-carboxycinnamic and diphenic acids, respectively. The catabolic versatility of strain AP1 and its use of ortho cleavage mechanisms during the degradation of polycyclic aromatic hydrocarbons (PAHs) give new insight into the role that pyrene-degrading bacterial strains may play in the environmental fate of PAH mixtures.

Decreased invasive capacity of quinolone-resistant Escherichia coli in patients with urinary tract infections

Quinolone-resistant (QR) Escherichia coli may have lower invasive capacity than does quinolone-susceptible E. coli. To evaluate this, we prospectively collected data regarding all cases of E. coli invasive urinary tract infections (IUTI) in 669 adults admitted to the Infectious Diseases Unit of our hospital during a 3-year period, as well as 10,950 patients with cystitis or asymptomatic bacteriuria who presented to the outpatient clinic during a 1-year period. QR E. coli was isolated in 20% of patients with cystitis, compared with 8% of those with IUTI (P<.05). The proportion of E. coli isolates that were quinolone resistant was similar in patients with bacteremic and nonbacteremic IUTI. The factors of urinary manipulation and structural abnormalities were independently associated with the presence of quinolone resistance. Old age was the only variable independently associated with blood invasion. QR E. coli is less likely to produce invasive disease (pyelonephritis and prostatitis) than is quinolone-susceptible E. coli. However, once pyelonephritis or prostatitis have developed, there is no difference in the incidence of bacteremia.

Use of a three-day estimated food record, a 72-hour recall and a food-frequency questionnaire for dietary assessment in a Mediterranean Spanish population

AIM

To assess the validity and the short-term reproducibility of a semi-quantitative, self-administrated food frequency questionnaire and a structured 72-hour recall in a Mediterranean Spanish population.

METHODS

44 free-living volunteers participated in the study. Macronutrient, vitamin and mineral intake, recorded on the food frequency questionnaire and the structured 72-h recall were compared with intakes derived from a three-day food record (reference method). Validity of the dietary assessment methods was further assessed by comparing urinary nitrogen, plasma vitamin C, plasma beta-carotene and whole blood glutathione peroxidase activity levels with the corresponding nutrient intakes from the questionnaires. The food frequency questionnaire and the 72-h recall were administered twice to assess the short term reproducibility.

RESULTS

Pearson's correlation coefficients between urinary nitrogen, plasma vitamin C, plasma beta-carotene and whole blood glutathione peroxidase activity levels and the reported nitrogen, vitamin C, beta-carotene and selenium intakes were 0.26, 0.53, 0.17, 0.26 for the food frequency questionnaire; 0.41, 0.09, 0.34, 0.42 for the structured 72-h recall and 0.50, 0.54, 0.44, 0.38 for the three-day food record, respectively. The short term reproducibility of analysed nutrient intake showed average intra-class correlation coefficients of 0.91 and 0.69 for the food frequency questionnaire and the structured 72-h recall irrespectively.

CONCLUSION

The food frequency questionnaire and the structured 72-h recall provide valid estimates of nutrient intake and could be used for dietary assessments.

Frequency of selection of fluoroquinolone-resistant mutants of Neisseria gonorrhoeae exposed to gemifloxacin and four other quinolones

We studied the frequency of mutation of clinical isolates of Neisseria gonorrhoeae (two nalidixic acid susceptible and two nalidixic acid resistant), and the stability of the mutants obtained, in the presence of three different concentrations of five fluoroquinolones. The frequency of mutation was low for all the quinolones. Only one N. gonorrhoeae mutant, obtained with trovafloxacin at 4 x MIC presented a stable increase in the MIC of this quinolone, not attributable to novel mutation(s), both in the gyrA and parC genes, although not showing any increase in the MIC of the other quinolones tested. In summary, gemifloxacin was the only quinolone tested for which resistant mutants were not obtained.

Characterization of sparfloxacin-resistant mutants of Staphylococcus aureus obtained in vitro

A sparfloxacin-susceptible clinical isolate of Staphylococcus aureus was grown in increased concentrations of sparfoxacin. The presence of mutations in gyrA, gyrB, grlA and grlB genes was analyzed. The primary point mutation was located in the gyrA gene (Glu-88 to Lys). Two further mutation steps appeared in the amino acid change Ser-80 to Tyr in GrlA. No mutations occurred in the gyrB or grlB genes. Efflux pumps involved in the increase of resistance were also found to affect norfloxacin and ciprofloxacin. This effect may be related to NorA. An overexpression of NorA, may be associated with the increase of the MIC of norfloxacin from 32 mg/l to >200 mg/l in the final mutant. The MICs levels of sparfloxacin were affected by unknown mechanism.