Evaluation of the SENIC risk index in a Spanish university hospital.

OBJECTIVE: To assess the performance of the Study of the Efficacy of Nosocomial Infection Control (SENIC) risk index for the evaluation of the risk of surgical-site infection (SSI) in a country other than the United States, having a different health system. SETTING: 350-bed university hospital in Spain belonging to the National Health System (Insalud). DESIGN: Observational cohort study of 1,019 patients who underwent consecutive surgery from January to December 1992. Surgical-infection risk factors assessed by the traditional wound-classification system (clean, clean-contaminated, contaminated, and dirty-infected wound) and by the SENIC risk index (length of intervention more than 2 hours, more than three discharge diagnoses, abdominal surgery, and contaminated or dirty-infected wound) were compared by forward logistic regression. RESULTS: The SENIC risk index showed a greater ability to predict SSI than the traditional wound-classification system. The study carried out in our institution reproduced the estimators provided by the SENIC study in the United States. The SENIC risk index provided a stepwise increase in SSI rates, according to the number of factors present, for every traditional wound-classification group. In the case of clean wounds, the incidence of surgical infection (per 100 interventions) increased (1.5, 2.4, 5.3, and 50; P<.001) for patients having from zero to three risk factors of the SENIC risk index. CONCLUSIONS: This study shows that the SENIC risk index results are reproducible, and the index can be used to compare rates of wound infection across countries with different health systems than the United States.

Evaluation of the Etest for penicillin susceptibility testing of Neisseria meningitidis.

Susceptibility to penicillin of 30 strains (one isolate per patient) of Neisseria meningitidis isolated from blood (N = 19) or cerebrospinal fluid (N = 11) was studied by two methods. Minimum inhibitory concentrations (MICs) obtained with the Etest were compared to those obtained by the National Committee for Clinical Laboratory Standards agar dilution method. Twenty meningococci (67%) relatively resistant to penicillin were identified by both methods. The mean MIC from the reference method was 0.32 micrograms/ml (range, 0.2-1) and by the Etest method was 0.35 micrograms/ml (range, 0.19-1.25). All MICs obtained by the Etest method were within one dilution of the MICs obtained by the reference method. Because of the increase in penicillin MIC of meningococcal isolates in Spain, we evaluated the performance of the Etest as an alternative method for penicillin-susceptibility testing of N. meningitidis. The Etest is a simple and accurate method for determining the susceptibility of N. meningitidis to penicillin.

[High incidence of ampicillin resistance in Salmonella spp non typhi]. / Alta frecuencia de elevada resistencia a ampicilina en Salmonella spp no typhi.

Salmonella spp non typhi is a common cause of gastroenteritis and, more rarely, extraintestinal infections in humans. The type of syndrome determines the choice and duration of antibiotic therapy. Extraintestinal infections by this organism require correct antibiotic therapy. In the present study, the susceptibility to antibiotics of 59 strains of Salmonella spp non typhi from clinical sources, isolated during a period of three and a half months, were evaluated. Fifty one of them were S. enteritidis, 7 S. typhimurium and 1 S. schwarzengrund. A high frequency (45.8%) of resistance to ampicillin (MIC greater than 256 micrograms/ml) was found. Other antibiotics had good or excellent in vitro activity: 90% of strains were sensitive to tetracyclines, 93% to chloramphenicol, 97% to co-trimoxazole, and 100% to cefotaxime and ciprofloxacine. It was concluded that the high frequency of ampicillin resistance to ampicillin precludes its use as first choice antibiotic in our area for suspected extraintestinal infections caused by Salmonella spp non typhi.

[Antibiotic sensitivity of strains of group A beta-hemolytic streptococci isolated recently]. / Sensibilidad a los antibióticos de cepas de estreptococo beta-hemolítico del grupo A aisladas recientemente.

The present study investigated the sensitivity of 35 group A beta-hemolytic streptococci strains, isolated from clinical samples in 1988 and 1989, to 12 antibiotics. The minimal inhibitory concentrations of each antibiotic were measured by the agar dilution method. All strains were sensitive to penicillin G, ampicillin, oxacillin, cefazolin, cefotaxime, erythromycin, clindamycin, vancomycin and ciprofloxacin. It was concluded that, in our area, Streptococcus pyogenes still has an excellent sensitivity to penicillin G and to other antibiotics which may be a therapeutic alternative in allergic patients or an empiric treatment in infections likely to be produced, among other organisms, by S. pyogenes.

[The prevalence of Escherichia coli susceptibility to quinolones and other antibiotics in community-acquired bacteriurias in Madrid]. / Prevalencia de susceptibilidad de Escherichia coli a quinolonas y otros antibióticos en bacteriurias extrahospitalarias de Madrid.

BACKGROUND: The empiric treatment of extrahospitalary urinary infections must keep in mind the patterns of susceptibility of the potentially causative bacteria. The consumption of antibiotics is one of the most important causes of change in the susceptibility of the bacteria. The recent introduction of fluorquinolones and the widespread use of those antibiotics makes knowledge of new patterns of sensitivity necessary in order to determine whether there are changing sensitive pattern among the different geographic zones. METHODS: During a period of two weeks randomly chosen 379 strains of Escherichia coli isolated from extrahospitalary bacteria were collected in 11 laboratories in 4 health areas in Madrid. Sensitivity to 11 antibiotics, including four of the quinolone group was determined by the agar dilution method. The existence of significant differences of sensitivity among the different areas was analyzed by the chi 2 test. RESULTS: The prevalence of sensitivity to ampicillin and cotrimoxazol was 42 and 73% respectively. Nineteen percent of the strains were resistant to amoxycillin/clavulanic acid. No strain was found to be resistant to cefotaxime. Four percent of the sample studied was not sensitive to the new fluorquinolones and almost 10% were resistant to nalidixic acid latter having decreased sensitivity to the fluorquinolones. No significant differences were observed in sensitivity among the areas, except with amoxycillin/clavulanic acid and cotrimoxazole. CONCLUSIONS: The high prevalence of the resistance of E. coli to ampicillin recently leads to the recommendation of its use in empiric treatments of urinary infections. In the zone in Madrid studied a high prevalence of resistance and decreased sensitivity of E. coli to fluoroquinolones was observed. It is therefore advisable to moderate their use to thereby prolong use over time.

[Dermatophytosis in a urban setting: prospective study of 135 cases]. / Dermatofitosis en el medio urbano: estudio prospectivo de 135 casos.

During a period of one year all patients referred to the Dermatology department with the diagnosis of dermatophytosis were studied to determine the incidence. Etiology, and epidemiology of these infections in the northeast of Madrid. We have evaluated the sensitivity and specificity of the direct examination with 10% KOH with respect to the culture as well as the correlation between the clinical diagnosis and the result of the mycologic examination. The annual incidence was 8.4 cases per 10,000 inhabitants and the most frequent causal agents in a total number of 135 patients were Epidermophyton floccosum in 48 (35.5%), Microsporum canis in 36 (26.6%), Trichophyton mentagrophytes in 28 (20.7%) and Trichophyton rubrum in 12 (8.8%). In 5 patients there were simultaneous infection by two different agents. In a third part of the cases a previous contact with animals was reported. The direct examination had a specificity of 98% and a sensitivity of 83%. The diagnosis in the nonungual infections was confirmed in the 54% of the cases. The incidence of dermatophytosis in our geographical area is high. Due to the similarities with other diseases, the mycologic examination by microscopy or culture is essential.

Long-term efficacy of a program to control methicillin-resistant Staphylococcus aureus.

The long-term efficacy of a program to control methicillin-resistant Staphylococcus aureus (MRSA) was evaluated in a 350-bed university hospital. Three periods were monitored: pre-epidemic (January 1989-November 1989), outbreak (December 1989-June 1990) and control program (July 1990-December 1992) periods. Control measures included cohort isolation, patient care measures and therapy (oral cotrimoxazole plus fusidic acid ointment) of MRSA carriage in patients, roommates and personnel. A total of 117 MRSA-infected patients were detected. For each period respectively, MRSA incidence (number of cases per 1,000 patient-days) was 3.2, 8.2 and 2.0 in the intensive care unit (ICU) and 0.08, 0.23 and 0.26 in the general wards. During the outbreak there was a 2.7-fold overall increase of baseline MRSA incidence (p < 0.02). The crude mortality was 68% and the attributable mortality was estimated to be 50%. The program was estimated to have prevented 76% (CI95 28-91, p < 0.0001) of expected MRSA cases and 85% (CI95 62-94, p < 0.0001) of expected fatalities due to MRSA in the ICU, but it had no significant effect in the general wards. The program did not control vancomycin consumption.