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Biomedical subjects

E Cercenado

Publications and source records attributed to E Cercenado.

At least 19 recordsLinked to original sources

Impact of the human immunodeficiency virus epidemic on detection of Mycobacterium isolates in a general hospital.

The number of human samples processed in our mycobacteriology laboratory ranged from 148 per 1,000 admissions in 1988 to 263 per 1,000 admissions in 1995 (5.2% were positive). The human immunodeficiency virus (HIV)-positive population contributed 33.3% of all samples, 43.3% of all isolates, and 36% of all new patients. Given that the ratios of the total number of samples to the number of Mycobacterium-positive samples were 18.3:1 in HIV-positive patients and 28:1 in HIV-negative patients, efforts to reduce the laboratory workload should begin with the HIV-negative population.

Disease Outbreaks

Comparative in-vitro activity of sparfloxacin and eight other antimicrobial agents against clinical isolates of non-tuberculous mycobacteria.

The in-vitro activity of sparfloxacin and eight other antimicrobial agents against 64 non-tuberculous mycobacteria (non-MAI) (40 rapidly growing and 24 slowly growing) was compared with those of ciprofloxacin, ofloxacin, amikacin, tobramycin, cefoxitin, imipenem, clarithromycin and doxycycline. Sparfloxacin presented the same activity as ciprofloxacin, being highly active against rapidly growing mycobacteria and showing good in-vitro activity against slowly growing mycobacteria. Amikacin was very active against rapidly growing mycobacteria and clarithromycin presented good activity against all mycobacteria tested. These results suggest that sparfloxacin is a valid agent to be considered in the treatment of Mycobacterium spp. infections.

Anti-Bacterial Agents

Multiply antibiotic-resistant Streptococcus pneumoniae recovered from Spanish hospitals (1988-1994): novel major clones of serotypes 14, 19F and 15F.

We analysed a collection of 95 multiply antibiotic-resistant pneumococci, recovered since 1988 from 14 Spanish hospitals, that have MICs > or = 0.25 microgram benzylpenicillin ml-1. The majority of the isolates were of serogroups 14, 23, 6, 19 and 15, which are currently the serogroups mainly associated with multiresistance in Spain. All of the serogroup 23 isolates were members of the major Spanish serotype 23F multiresistant clone. Similarly, most of the serogroup 6 isolates were members of the major multiresistant serotype 6B clone, or variants of this clone. Eighteen of the 24 isolates of serogroup 19 were members of a highly penicillin-resistant clone that appears to be a serotype 19F variant of the major Spanish serotype 23F multiresistant clone. Eighteen of the 25 isolates of serotype 14 were members of a previously uncharacterized highly penicillin-resistant clone. Thirteen of the 16 isolates of serogroup 15 were members of a single previously unreported clone of serotype 15F that had moderate levels of resistance to penicillin. Approximately 65% of the multiresistant pneumococci that are currently circulating in Spain were members of the three new clones of serotype 14, 15F and 19F that we describe here, or the previously described serotype 6B and 23F clones. The other 35% of isolates were minor variants of the major clones, unrelated minor clones, and unique isolates, many of which appeared to have arisen by horizontal gene transfer events.

Bacterial Proteins

Characterization of clinical isolates of beta-lactamase-negative, highly ampicillin-resistant Enterococcus faecalis.

We analyzed the penicillin-binding protein (PBP) profiles of two clinical isolates of Enterococcus faecalis for which ampicillin MICs were 32 and 64 micrograms/ml. Six PBPs were detected in both isolates, demonstrating an apparently increased amount of PBP 5 and decreased penicillin binding of PBPs 1 and 6. These results suggest that ampicillin resistance in the clinical isolates of E. faecalis described could be associated with alterations in different PBPs.

Ampicillin Resistance

Emergence of teicoplanin-resistant coagulase-negative staphylococci.

Over a period of 5 years we have recovered 32 clinical isolates of coagulase-negative staphylococci (CoNS) exhibiting either decreased levels of susceptibility or true resistance to teicoplanin (MICs, 16 to 128 micrograms/ml); these isolates make up 0.55% of the total CoNS isolated by us. Twenty-nine of the strains were also methicillin resistant, and all were susceptible to vancomycin. Fourteen of the strains were Staphylococcus epidermidis, fourteen were Staphylococcus haemolyticus, and four were Staphylococcus hominis. In one case, a strain of S. haemolyticus was isolated with a vancomycin-resistant, teicoplanin-resistant Enterococcus faecalis strain. All strains were nosocomially acquired and were isolated from 17 different wards. Teicoplanin resistance occurred as a sporadic phenomenon, and none of the isolates were epidemiologically related. The isolates were from 30 patients, 13 of whom presented with true infections (43%). Five (38%) of the 13 patients with true infections had been previously treated with vancomycin. None of the infected patients were previously treated with teicoplanin. The in vivo development of resistance to teicoplanin among CoNS strains limits the therapy of infections by these microorganisms. There is a need for surveillance of nosocomial isolates of CoNS to determine resistance to glycopeptides.

Aged

Variability of Leishmania (Leishmania) infantum among stocks from immunocompromised, immunocompetent patients and dogs in Spain.

Leishmania (Leishmania) infantum is the causative agent of both the cutaneous and visceral forms of leishmaniasis in southwest Europe; the dog is the main reservoir. In order to identify the L. (L.) infantum zymodemes present in Spain, a total number of 85 Leishmania stocks isolated from dogs (31), HIV-positive patients (46) with visceral or cutaneous leishmaniasis, a patient with visceral leishmaniasis complicating renal transplantation (1) and immunocompetent patients (7) with visceral or cutaneous leishmaniasis, have been characterized by isoenzyme typing. All canine stocks were MON-1, which is the most widespread zymodeme in the Mediterranean area. In immunocompetent patients three zymodemes were found: MON-1 (2), MON-24 (2) and MON-34 (3). Nine different zymodemes were obtained in stocks from HIV co-infected patients, indicating a higher variability of L. (L.) infantum amongst them: MON-1 (in 21 stocks), MON-24 (7), MON-28 (1), MON-29 (3), MON-33 (7), MON-34 (1) and MON-183 (4). Two new zymodemes, MON-198 (1) and MON-199 (1), were described among HIV patients from Spain. The stock from the renal transplanted patient was MON-1. The exclusive presence of certain zymodemes in immunocompromised patients and their absence in typical cases of cutaneous and visceral leishmaniasis and in infected dogs suggests two possibilities: (i) an anthroponotic pattern of leishmaniasis where intravenous drug user-infected patients act as potential reservoir for these new zymodemes. In the latter, syringes could act as the vehicles for infected monocytes; (ii) the cellular immune system could select virulent from non-virulent zymodemes in immunocompetent visceral leishmaniasis patients.

AIDS-Related Opportunistic Infections

Infections caused by erythromycin-resistant Streptococcus pneumoniae: incidence, risk factors, and response to therapy in a prospective study.

To evaluate the incidence and the significance of resistance to erythromycin among clinical isolates of Streptococcus pneumoniae, we identified and prospectively followed all hospitalized patients in a 27-month period who had the organism isolated from any clinical sample. Patients who had an infection caused by pneumococci resistant to erythromycin (minimum inhibitory concentration, > 1 microgram/mL) were compared to those with infections caused by erythromycin-susceptible organisms. The incidence of erythromycin resistance among pneumococci doubled over the study period (from 7.6% in 1988 to 15.2% in 1992). Most strains (94%) showed resistance to multiple antibiotics, including other macrolides. By multivariate analysis, an age of < 5 years and nosocomial acquisition of the infection were independent risk factors for erythromycin resistance. Among patients with pneumococcal pneumonia caused by erythromycin-resistant organisms, 9 patients treated with third-generation cephalosporins were cured, while therapy with erythromycin failed for 2 of the 6 patients to whom it was administered. The rapid and significant increase of erythromycin resistance among clinical isolates of S. pneumoniae points to the need for routine surveillance of pneumococcal resistance.

Adolescent

Characterization of vancomycin resistance in Enterococcus durans.

During investigation of an outbreak of vancomycin resistant Enterococcus faecium in a paediatric hospital, an isolate of Enterococcus durans resistant to vancomycin, teicoplanin, ampicillin and highly resistant to gentamicin and streptomycin was found in the stools of a patient also colonized with a strain of E. faecium with the same resistance pattern. Minimal inhibitory concentrations of vancomycin and teicoplanin were 512 and 64 mg/mL, respectively. Resistance to vancomycin as well as high-level resistance to gentamicin was transferable to an E. faecium recipient strain. Both multiresistant E. faecium and E. durans isolates as well as the transconjugant presented only one plasmid. The vanA gene was detected and localized to the high molecular weight plasmid by DNA hybridization with a vanA gene probe. Growth in vancomycin resulted in induction of an approximately 40 kDa protein visible in membrane preparations from these cells. Genetic linkage between vancomycin and gentamicin resistance genes in the same plasmid is suggested.

Anti-Bacterial Agents

Comparative study of mupirocin and oral co-trimoxazole plus topical fusidic acid in eradication of nasal carriage of methicillin-resistant Staphylococcus aureus.

Mupirocin is a topically applied drug that is very active in the eradication of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). However, studies designed to compare mupirocin treatment with other antimicrobial regimens are lacking. We therefore conducted an open, prospective, randomized, controlled trial to compare the efficacy and safety of mupirocin versus those of oral co-trimoxazole plus topical fusidic acid (both regimens with a clorhexidine scrub bath) for the eradication of MRSA from nasal and extranasal carriers of MRSA. The eradication rates with mupirocin and co-trimoxazole plus fusidic acid at 2, 7, 14, 21, 28, and 90 days were 93 and of 93, 100 and 100, 97 and 94, 100 and 92, 96 and 95, and 78 and 71%, respectively, for nasal carriage. At 7, 14, and 28 days the eradication rates for extranasal carriage by the two regimens were 23 and 74, 83 and 76, and 45 and 69%, respectively. The efficacies and safety of both regimens were similar. The MRSA isolates were not resistant to the study drugs either at the baseline or at follow-up. These results suggest that mupirocin and co-trimoxazole plus fusidic acid, both used in conjunction with a chlorhexidine soap bath, are equally effective and safe for the eradication of MRSA from nasal and extranasal MRSA carriers. Mupirocin was easier to use but was more expensive.

Administration, Oral

Enhanced activity of the combination of penicillin G and gentamicin against penicillin-resistant viridans group streptococci.

We evaluated the effects of the combination of penicillin G and gentamicin against 10 penicillin-resistant bacteremic isolates of viridans group streptococci for which the MICs of penicillin were 4 to 64 micrograms/ml. In time-kill studies, the combination resulted in more killing of eight isolates for which the MICs of penicillin were from 8 to 64 micrograms/ml than any of the antimicrobial agents tested alone. In general, clearly enhanced antimicrobial activity was observed with the combination.

Anti-Bacterial Agents

Genetics of oxacillin resistance in clinical isolates of Streptococcus pneumoniae that are oxacillin resistant and penicillin susceptible.

It has recently been reported that penicillin-sensitive pneumococci may exhibit reduced susceptibility to oxacillin, resulting in their misclassification as being penicillin resistant by oxacillin disk testing. Intermediate oxacillin resistance (MIC, 1.0 microgram/ml) in three of these apparently unrelated penicillin-susceptible clinical isolates of Streptococcus pneumoniae isolated in the United Kingdom and in four Spanish isolates was shown to be solely due to the acquisition of a gene encoding an altered penicillin-binding protein (PBP), PBP2X. PBP2X genes cloned from typical penicillin-resistant isolates of S. pneumoniae that possessed high-level oxacillin resistance were shown to be able to transform susceptible isolates of S. pneumoniae to intermediate oxacillin resistance. In all instances, the intermediately oxacillin-resistant PBP2X transformants retained susceptibility to penicillin (MIC, 0.06 microgram/ml). Under appropriate selective pressure, the acquisition of a low-affinity PBP2X by penicillin-susceptible pneumococci could result in an increasing number of false positives for penicillin resistance among isolates of S. pneumoniae screened with oxacillin. Additionally, these intermediately oxacillin-resistant isolates showed reduced susceptibility to cefotaxime, an agent likely to be prescribed in place of penicillin for the treatment of serious infections due to these apparently penicillin-resistant organisms.

Bacterial Proteins

Impact of an educational program for the prevention of colonization of intravascular catheters.

OBJECTIVE: To evaluate the efficacy of an educational program for the prevention of catheter colonization. DESIGN: Two cross-sectional studies were carried out in a 500-bed randomly selected area of the hospital, separated by an educational program on the care of intravenous lines based on the Centers for Disease Control and Prevention (CDC) recommendations for the control of catheter-related infections. SETTING: A 2,100-bed urban general hospital affiliated with the University of Madrid (Spain). METHODS: Characteristics of patients and catheters and appropriateness of catheter care were evaluated. Cultures were taken from the point of insertion of the vascular catheter, the hubs, and infusion fluids. When catheter-associated infection was suspected, the distal end of the catheter was sent for culture and two blood cultures were taken. We compared the clinical and microbiological data before and after carrying out an educational program based on CDC recommendations for the control of catheter-related infections. RESULTS: Characteristics of patients and catheters did not differ between the two cross-sectional studies. Compared with baseline data, after the educational program we observed a reduction of inappropriate catheter care, from 83% to 38% (45% difference, 95% confidence interval [CI95], 55% to 35%, P < 0.0000), and a reduction in the rate of skin colonization, from 34% to 18% (16% difference, CI95, 26% to 5%, P < 0.001). The frequency of phlebitis (15% versus 14%), hub colonizations (12% versus 11%), catheter colonizations (2% versus 1%), and catheter-related bacteremias (0% versus 0%) remained unchanged between the two cross-sectional studies. CONCLUSIONS: Our educational program improved catheter care and reduced significantly the proportion of skin colonization around the insertion point. However, the educational program did not modify the proportion of hub colonization; because hub colonization has been demonstrated to be a source of line sepsis, our data suggest the need for a specific program directed to the maintenance of catheter hubs.

Adult

Rapid screening of Salmonella species from stool cultures.

The authors compared a three-minute fluorescence method (MUCAP test; Biolife Italiana, Milan, Italy) with standard microbiologic procedures for the presumptive identification of Salmonella from stool cultures on three solid culture media. From 976 suspect colonies, 176 proved to be Salmonella by the traditional methods. They all were detected by the MUCAP test (sensitivity, 100%). There were 65 false-positive results, corresponding mostly to Pseudomonas (specificity, 91.8%). Neither the culture medium used nor the production of H2S affected the accuracy of the test. The results from this study showed that the MUCAP test is a rapid, simple, and sensitive method for the presumptive identification of Salmonella species.

Evaluation Studies as Topic

Antimicrobial resistance of Salmonella isolates in a Spanish hospital.

We studied 961 clinical Salmonella isolates (one per patient) seen in one Spanish hospital from 1988 to 1991. The incidence of non-Salmonella typhi Salmonella infections per 100,000 admissions increased from 3.93 to 5.98. Overall rates of resistance to ampicillin, chloramphenicol, and co-trimoxazole were 32, 11, and 2%, respectively. Resistance to chloramphenicol increased from 9 to 16% during the study period, while resistance to each of the other drugs remained stable. Variations related to serogroups were observed.

Ampicillin

A gene conferring resistance to vancomycin but not teicoplanin in isolates of Enterococcus faecalis and Enterococcus faecium demonstrates homology with vanB, vanA, and vanC genes of enterococci.

We report the sequence of a 630-bp fragment of a gene associated with resistance to high levels of vancomycin in a clinical isolate of Enterococcus faecalis which retained susceptibility to teicoplanin. This gene was similar to the recently sequenced vanB and partially homologous with vanA, but it showed less-marked similarity to vanC. A DNA probe, derived from this polymerase chain reaction-amplified gene fragment, hybridized specifically with genomic DNA from Enterococcus faecium and E. faecalis isolates which were vancomycin resistant (MICs ranged from 8 to 512 micrograms/ml) but susceptible to teicoplanin. Curing of vancomycin resistance was associated with loss of DNA hybridization with the gene probe. Transfer of DNA which hybridized with the probe accompanied transfer of vancomycin resistance to a susceptible recipient strain. Neither curing nor transfer of vancomycin resistance was consistently related to loss or acquisition, respectively, of plasmid DNA.

Amino Acid Sequence