[Evolution of microbial resistance to fluoroquinolones at a tertiary hospital]

Etiological and Resistance Profile of Bacteria Involved in Urinary Tract Infections in Young Children

Background. The objective of this study was to identify the bacteria most frequently responsible for urinary tract infection (UTI) in the population of under-2-year-olds in our geographic area and to evaluate the activity of antibiotics widely used for UTI treatment during a 4-year study period. Materials and Methods. A retrospective analysis was conducted of data on the identification and susceptibility of microorganisms isolated in urine samples from children under 2 years of age. Results. A total of 1,045 uropathogens were isolated. Escherichia coli accounted for the majority (60.3%) of these, followed by Enterococcus faecalis (22.4%) and Klebsiella spp. (6.5%). The highest E. coli susceptibility rates (>90%) were to piperacillin-tazobactam, cefuroxime, cefotaxime, ceftazidime, imipenem, gentamicin, nitrofurantoin, and fosfomycin, and the lowest were to amoxicillin-clavulanic acid and cotrimoxazole. Among all bacteria isolated, we highlight the overall high activity of piperacillin-tazobactam, imipenem, nitrofurantoin, and fosfomycin against both community and hospital isolates and the reduced activity of amoxicillin-clavulanic acid, cephalosporins, gentamicin, and cotrimoxazole. There was no significant change in the total activity of any of the studied antibiotics over the 4-year study period. Conclusion. Empiric treatment with amoxicillin-clavulanic acid, cotrimoxazole, cephalosporins, and gentamicin may be inadequate due to their limited activity against uropathogens in our setting.

[Urinary infection in patients with neurogenic bladder: patterns of resistance to the most frequent uropathogens]

PURPOSE

To analyze the most frequent causes and resistances of the uropathogens in patients affected by neurogenic bladder.

MATERIAL AND METHODS

A total of 284 patients, in whom a total of 284 urinary cultures were performed, were included. Of these, 106 came from patients with neurological injuries, 28 from a non-neurogenic control group, 75 from patients admitted to the intensive care unit (ICU) of our Hospital and 75 patients who came into the emergency room with the symptoms of an acute urinary tract infection. A quantitative urine culture was performed in a chromogenic media and the resistances of all urine cultures that were positive for one or two micro-organisms were identified and studied.

RESULTS

A total of 67% of the patients with neurological injuries had positive urine cultures compared to 25% of control group patients. The urine cultures of patients admitted into the ICU and those of the Emergency Room group were 100% positive, since the first 75 positive urine cultures were selected for the study. E.coli was the most-frequently microorganism isolated in the group of neurological patients, as well as among the patients from the Emergency Room and from the control group. In the ICU, the most-frequently isolated micro-organism was Enterococcus spp. (19.4%), followed by P. aeruginosa (16.5%). The study of resistances in general E. coli has high rates of resistance to ampicillin and co-trimoxazole and, although to a lesser degree to ciprofloxacin.

CONCLUSIONS

E. coli is the micro-organism most frequently isolated among all of the groups except in the ICU, where it is surpassed by Enterococcus spp. and P. aeruginosa. The resistances among the four population groups studied have different features, overall showing a low rate of resistance to nitrofurantoin and especially to fosfomycin, observed in patients from the Emergency Room or admitted to the ICU and neurological patients.

[Etiological profile of urinary tract infections and antimicrobial susceptibility of urinary pathogens]

A review on the etiological profile of urinary tract infections in childhood and the sensitivity pattern of urinary pathogens in Spain is presented. Escherichia coli continues to be the main etiological agent of urinary tract infection in childhood. Consequently, its sensitivity pattern will usually determine the choice of empirical therapy. The predominance of E. coli is reduced in certain circumstances, in which the presence of other microorganisms is increased. However, the clinical information available at diagnosis does not allow accurate identification of the etiology; only staining and microscopic urine examination can help in treatment selection. In Spain, E. coli presents a high percentage of resistance to ampicillin and cotrimoxazole, whereas second- and third-generation cephalosporins, fosfomycin, aminoglycosides and amoxicillin-clavulanate maintain high sensitivity. In some areas, amoxicillin-clavulanate and first-generation cephalosporins show high levels of resistance, which can limit their empirical use.

Contribution of a new mutation in parE to quinolone resistance in extended-spectrum-beta-lactamase-producing Escherichia coli isolates

Mutations in the quinolone resistance-determining regions of gyrA, gyrB, parC, and parE were studied in 30 fluoroquinolone-resistant clinical isolates of Escherichia coli producing extended-spectrum beta-lactamases. Ten isolates showed a mutation in parE that was significantly associated with an increase in the MIC for fluoroquinolones.

[Microbial sensitivity of Escherichia coli in community-acquired urinary tract infections]

OBJECTIVE

For effective empiric therapy of urinary tract infections in the extra-hospital setting the susceptibility pattern of uropathogens should be considered. Moreover, the evolution in sensitivity can be observed when comparing with susceptibility patterns in the previous years. This paper presents an analysis of our experience with Escherichia coli.

MATERIAL AND METHODS

During 2002 and 1998, 895 and 595 strains of Escherichia coli respectively, isolated from extrahospitalary bacteriurias were collected in ten health centers in Bierzo (León, Spain). Sensitivity to nine most commonly antibiotics used in the clinical practise was determined. The existence of significant differences of susceptibility among years (2002-1998) was analyzed by the chi square test.

RESULTS

Escherichia coli accounted for 63.4% of all isolates in 2002 and 50.8% in 1998. The prevalence of in-vitro susceptibilities to antibiotics were (2002-1998): fosfomycin (99.2%-99.3%; p = NS*), cefixime (98.3%-92.9%; p < 0.001), cefuroxime (96.5%-94.1%; p < 0.05), nitrofurantoin (94.5%-86.9%; p < 0.001), amoxycillin-clavulanic acid (93.1%-90.1%; p < 0.05), ciprofloxacin (77.1%-81.6%; p < 0.05), norfloxacin (75.8%-80.3%; p < 0.05), cotrimoxazole (71.5%-73.4%; p = NS*) and ampicillin (44%-41.4%; p = NS*). (*NS = No significant differences).

CONCLUSION

The knowledge of the sensitivity of uropathogens to antimicrobians in a specific medium can allow us to use antibiotics rationally and initiate empirical therapy.

Sensibilidad microbiana de escherichia coli en bacteriurias en el área sanitaria del bierzo en el año 2003

OBJECTIVE

Sensitivity to antibiotics of Escherichia coli isolated from intrahospital and extrahospital bacteriurias is analyzed.

MATERIAL AND METHODS

Sensitivity to nineteen antibiotics used in the clinical practice was determined in strains of Escherichia coli isolated from intrahospital and extrahospital bacteriurias.

RESULTS

The prevalence of in-vitro susceptibilities to antibiotics were (hospital, state health service clinic, health center-primary-care): imipenem (100%-100%-100%; p=NS), amikacin (100%-100%-99.7%; p=NS), fosfomicyn (98.6%-98.4%-99.6%; p=NS), cefepime (96%-96.9%-98.3%; p=NS), piperacillin-tazobactam (96%-95.3%-96.6%; p=NS), aztreonam (93.5%-94.7%-97.7%; p<0.001), ceftazidime (93.5%-94.3%-97.8%; p<0.001), cefotaxime (93.1%-95%-97.7%; p<0.001), cefixime (92.7%-94.6%-96.7%; p<0.05), nitrofurantoin (92%-94.7%-94.7%; p=NS), cefuroxime (88.4%-93.1%-95%; p<0.001), amoxicillin-clavulanic (87.7%-88.7%-93.8%; p<0.001), tobramicyn (87%-93.7%-93.8%; p<0.001), gentamcin (85.9%-92.8%-93%; p<0.001), cefazolin (84.4%-88.7%-91.6%; p<0.01), ciprofloxacin (63.8%-71.4%-78.4%; p<0.001), norfloxacin (63%-70.8%-78.2%; p<0.001), cotrimoxazole (65.2%-68.6%-74.9%; p<0.01) and ampicillin (35.5%-42.5%-47.8%; p<0.01). (*NS= No significant differences).

CONCLUSIONS

The knowledge of the sensitivity of uropathogens to antimicrobians can allow us to initiate empirical therapy of urinary tract infections.

[Acute cystitis in women. Current microbial sensitivity in our setting]

INTRODUCTION AND OBJECTIVE

Acute cystitis is the most frequent symptomatic infection in females and the urological condition which results in more visits to the clinic. The empirical treatment commonly instituted requires a continuous update of local microbial susceptibility to keep resistance emergence under control and reduce costs. Our goal was to study the current susceptibility of all urological pathogens isolated in acute cystitis in female patients.

MATERIAL AND METHODS

Prospective study on 218 cases of acute cystitis in females reported between March 2000 and November 2000 in Health Centres within our Health Care Area. Patients were distributed by age range also including other parameters such as history of previous cystitis and predisposing factors, clinical sings and symptoms, as well as isolated micro-organisms and their "in vitro" susceptibility and MIC (Minimum Inhibitory Concentration) against the anti-microbial agents most commonly used in the clinical practice.

RESULTS

The larger age groups were 25-35 and 65-75 years. 162 cases were intermittent and 56 were repeat cystitis. Haematuria was present in 14% cases. The microbial spectrum was similar in all groups; overall E. coli was isolated in 82.1% cases, K. pneumonia in 6%, S. agalactiae 3.7%, E. faecalis 2.3%, P. mirabilis 1.8% etc. Resistance rates for E. coli were: 0.6% for cefixime, 1.1% for amoxycillin-clavulanate, 1.7% tobramycin, 2.8% fosfomycin, 3.3% nitrofurantoin, 18.4% ciprofloxacin, 19.6% norfloxacin, 22.3% pipemidic acid, 35.8% co-trimoxazol and 54.7% ampicillin. Repeat cystitis was more frequent in patients over 65 years with higher resistance rates mainly in the quinolones group (28.6% ciprofloxacin and 30.4% norfloxacin for E. coli). Mean MIC for ciprofloxacin with regard to E. coli was: 1.503 mcg/mL (range: 0.06-8) and 3.96 mcg/mL (range: 1-16) for amoxycillin-clavulanate.

CONCLUSION

High E. coli resistance rates to quinolones are still persistent. Excellent susceptibility to amoxycillin-clavulanate, cefixime and aminoglycosides, which allows for their use in short-term treatment regimes. High resistance rates to urinary antiseptic agents such as co-trimoxazol and ampicillin, and low rates for agents such as fosfomycin and nitrofurantoin.