[Changes in the epidemiology of Clostridium difficile infection during 2005-2014 in Salamanca, Spain]. / Cambios en la epidemiología de la infección por Clostridium difficile durante 2005-2014 en Salamanca, España.

OBJECTIVE: To know the most relevant epidemiological features of Clostridium difficile infection (CDI) between 2005- 2014 in the province of Salamanca (Spain). METHODS: Descriptive cross-sectional study carried out through review of the clinical microbiologic records at Complejo Asistencial Universitario de Salamanca. Detection was performed according to standard methodology. RESULTS: 2.6% of stool samples analyzed for detection of C. difficile toxins (9,103) were positive. The average prevalence was 6.8 cases per 100,000 people per year. The mean age was 65 ± 21.4 years and the median 70 years. 59% of cases occurred in patients over 64 years, with an average prevalence of 16.5 (4 times higher than the 15-64 group). Most cases (86.4%) occurred in hospitalized patients, and the group of over 64 had the highest percentage of hospital CDI, with 55%. CONCLUSIONS: A significant increase in the number of requests and in the prevalence of CDI over the decade studied is observed, and prevalence rates were significantly lower than those of other studies. The percentage of CDI increased significantly in both inpatient and community. Age and hospitaliza-tion were risk factors for developing CDI. After the introduc-ion of a molecular detection technique in 2014, the prevalence increased, being 2.5 times higher than 2013.

Microorganisms direct identification from blood culture by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows a fast and reliable bacterial identification from culture plates. Direct analysis of clinical samples may increase its usefulness in samples in which a fast identification of microorganisms can guide empirical treatment, such as blood cultures (BC). Three hundred and thirty BC, reported as positive by the automated BC incubation device, were processed by conventional methods for BC processing, and by a fast method based on direct MALDI-TOF MS. Three hundred and eighteen of them yield growth on culture plates, and 12 were false positive. The MALDI-TOF MS-based method reported that no peaks were found, or the absence of a reliable identification profile, in all these false positive BC. No mixed cultures were found. Among these 318 BC, we isolated 61 Gram-negatives (GN), 239 Gram-positives (GP) and 18 fungi. Microorganism identifications in GN were coincident with conventional identification, at the species level, in 83.3% of BC and, at the genus level, in 96.6%. In GP, identifications were coincident with conventional identification in 31.8% of BC at the species level, and in 64.8% at the genus level. Fungaemia was not reliably detected by MALDI-TOF. In 18 BC positive for Candida species (eight C. albicans, nine C. parapsilosis and one C. tropicalis), no microorganisms were identified at the species level, and only one (5.6%) was detected at the genus level. The results of the present study show that this fast, MALDI-TOF MS-based method allows bacterial identification directly from presumptively positive BC in a short time (<30 min), with a high accuracy, especially when GN bacteria are involved.

In vitro susceptibility of community-acquired urinary tract pathogens to commonly used antimicrobial agents in Spain: a comparative multicenter study (2002-2004).

The susceptibility patterns of 2724 uropathogens isolated in 9 Spanish regions during 2002, and 3013 obtained in 2004 were determined. The antibiotics tested were fosfomycin trometamol, amoxicillin, co-amoxiclav, cefixime, cefuroxime-axetil, pipemidic, ceprofloxacin, trimethoprim plus sulphamethoxazole and nitrofurantoin. Escherichia coli was the main pathogen in both studies (73% vs. 68.3%) followed by Proteus mirabilis 7.2% vs. 6.4%) and Klebsiella pneumoniae (5.4% vs. 5.2%). Enteroccocus spp. (4.7% vs. 6.8%), Streptoccocus agalactiae (1.7% vs. 3.1%) and Staphyloccocus saprophyticus (0.7% vs. 1.3%)were the most frequent Gram-positive pathogens. 31.3% of E. coli in 2002 and 32% in 2004 were susceptible to all antibiotics tested. Around 40% of E. coli were resistant to a single agent. 21.6-24.1% were resistant to two antibiotics. 35.4% of first period isolates, and 37.6% of second period ones were resistant to two or more classes of antibiotics. Fosfomycin (2.1- 2.8%) and nitrofurantoin (3.5-5.7%) had the lowest resistance rates for E. coli. Amoxicillin (58.2-58.7%), co-trimoxazole (30.8-33.8%) and ciprofloxacin (22.6-22.7%) showed the highest resistance rates, and their suitability as empiric treatments for UTI should probably be re-evaluated.

Molecular epidemiology of drug-resistant Salmonella Typhimurium in Spain.

One hundred and forty-seven Salmonella serotype Typhimurium strains isolated in three provinces in the midwest of Spain were studied. Of these, 93.6% were drug resistant. There were two predominant resistance phenotypes: 43 isolates (29.3%) were resistant to amoxicillin, tetracyclines, chloramphenicol, streptomycin and sulphamethoxazole and 27 isolates (18.4%) to amoxicillin, amoxicillin/clavulanic acid, tetracyclines, chloramphenicol, streptomycin and sulphamethoxazole. Randomly amplified polymorphic DNA (RAPD) analysis and pulsed field gel electrophoresis (PFGE) were performed for molecular typing. Thirty-six DNA band profiles were differentiated by RAPD, and 38 by PFGE. We found a high level of clonality; 27% of strains were identical by both methods. There were additional smaller clonal lines within every area. The highest discriminatory power was obtained with PFGE, but the greatest degree of genetic diversity was observed among Salmonella Typhimurium using both RAPD and PFGE.

Molecular epidemiology of drug-resistant Salmonella Typhimurium in Spain

One hundred and forty-seven Salmonella serotype Typhimurium strains isolated in three provinces in the midwest of Spain were studied. Ofthese, 93.6% were drug resistant. There were two predominant resistance phenotypes: 43 isolates (29.3%) were resistant to amoxicillin, tetracyclines,chloramphenicol, streptomycin and sulphamethoxazole and 27 isolates (18.4%) to amoxicillin, amoxicillin/clavulanic acid, tetracyclines,chloramphenicol, streptomycin and sulphamethoxazole. Randomly amplified polymorphic DNA (RAPD) analysis and pulsed field gelelectrophoresis (PFGE) were performed for molecular typing. Thirty-six DNA band profiles were differentiated by RAPD, and 38 by PFGE. Wefound a high level of clonality; 27% of strains were identical by both methods. There were additional smaller clonal lines within every area.The highest discriminatory power was obtained with PFGE, but the greatest degree of genetic diversity was observed among SalmonellaTyphimurium using both RAPD and PFGE

Se estudiaron 147 de cepas de Salmonella serotipificadas como Typhimurium procedentes de tres provincias españolas del medio-oeste. El93,6% de ellas eran resistentes a los antimicrobianos. Hubo dos fenotipos de resistencia predominantes: 43 cepas (29,3%) fueron resistentesa amoxicilina, tetraciclinas, cloranfenicaol, estreptomicina y sulfametoxazol, y 27 (18,4%) a amoxicilina, amoxicilina-ácido clavulánico, tetraciclinas,cloranfenicol, estreptomicina y sulfametoxazol. Los distintos patrones de resistencia se determinaron por técnicas de biología molecular:RAPD (Randomly Amplified Polymorphic DNA) y PFGE (Pulsed Field Gel Electrophoresis). Por RAPD se diferenciaron 36 patrones debandas, y por PFGE 38. Se encontró una proporción alta de clones: el 27% de las cepas fueron idénticas por ambos métodos. Además, encada área se encontraron algunos clones diferentes adicionales. Con PFGE se obtuvo el mayor poder discriminatorio, pero el mayor gradode diversidad genética se observó usando ambas técnicas conjuntamente

[Antimicrobial drug resistance in non-typhi Salmonellae in Castilla y Leon]. / Resistencia a antimicrobianos en Salmonella no typhi en Castilla y León.

We studied the antibiotic susceptibility of 309 Salmonella isolates obtained from three hospitals serving the provinces of Salamanca, Avila and Zamora in the region of Castilla y Leon (mid-west Spain). The susceptibility to 18 antibiotics was studied using the agar dilution method, according to NCCLS guidelines, and the most common multiresistance phenotypes were determined for each province. We observed clear susceptibility differences between the two main serotypes found, S. enteritidis and S. typhimurium. Seventy percent of S. typhimurium were resistant to amoxicillin. In 44% of these isolates, amoxicillin resistance was associated with resistance to streptomycin, sulfonamides, tetracyclines and chloramphenicol. S. enteritidis was susceptible to most antibiotics tested; amoxicillin resistance was observed in 23.3%, and nalidixic acid resistance in 49.6%. Resistance to nalidixic acid was higher in S. enteritidis than in any other serotypes. According to NCCLS breakpoints, no strain was resistant to fluoroquinolones. However, according to MENSURA criteria, 9% of S. typhimurium isolates were resistant to ciprofloxacin. Resistance to cotrimazole and gentamicin was less than 10% for all the serotypes tested. The results indicate that S. typhimurium showed greater resistance and a high multidrug resistance rate. Conversely, S. enteritidis showed high resistance only to amoxicillin and nalidixic acid, though in most cases there was no correlation between this resistance and reduced susceptibility to fluoroquinolones.

In vitro activity of BAY y 3118, and nine other antimicrobial agents against anaerobic bacteria.

The antibacterial activity of BAY y 3118, a new chlorofluoroquinolone, was determined against 257 strains of anaerobic bacteria and compared with the activities of ofloxacin, ciprofloxacin, sparfloxacin, imipenem, cefoxitin, clindamycin, chloramphenicol, metronidazole, and ornidazole. Overall, BAY y 3118 was the most active agent tested against the Bacteroides fragilis group. Its activity (MIC90, 0.5 mg/L) was 16-fold lower than that of sparfloxacin (MIC90, 8 mg/L), and more than 100-fold lower than that of ofloxacin (MIC90, 64 mg/L) and ciprofloxacin (MIC90, 128 mg/L) against the group. No strains belonging to this group were resistant to metronidazole (MICs range, 0.12-2 mg/L) and ornidazole (MICs range, 0.12-4 mg/L). BAY y 3118 was more active than those quinolones against Prevotella and Porphyromonas spp., Fusobacterium spp., Clostridium perfringens and C. difficile (MIC90, 0.12, 0.06, 0.12 and 0.25 mg/L, respectively). The activity of BAY y 3118 against Peptostreptococcus spp. (MIC90, 1 mg/L) was slightly lower than that of the other Gram-positive bacteria tested. In general, BAY y 3118 was more active than cefoxitin, and it was superior to antianaerobic chemical agents like metronidazole, ornidazole and clindamycin. Pharmacokinetic and clinical trials are required to define the role of BAY y 3118 in the treatment of anaerobic infections.

Susceptibilities of Brucella melitensis isolates to clinafloxacin and four other new fluoroquinolones.

The susceptibilities of 120 clinical isolates of Brucella melitensis and 3 reference strains of the same species to six fluoroquinolones (clinafloxacin, PD 117596, PD 131628, PD 138312, PD 140248, and ciprofloxacin) were examined by agar dilution MIC methodology. Clinafloxacin was the most active compound tested (MIC at which 50% of strains tested were inhibited [MIC50] and MIC90 of 0.06 micrograms/ml). Its level of activity was slightly higher than that of PD 117596 (MIC50 and MIC90 of 0.12 micrograms/ml). PD 131628 and ciprofloxacin were less active than clinafloxacin, with MIC50s ranging from 0.12 to 0.25 micrograms/ml and MIC90s of between 0.25 and 0.5 micrograms/ml for the two compounds. The activity levels of PD 138312 and PD 140248, with MIC50s ranging from 1 to 2 micrograms/ml and MIC90s of 4 to 8 micrograms/ml, were lower than those of the other fluoroquinolones tested.

In-vitro activity of four new fluoroquinolones.

The in-vitro activities of four new fluoroquinolones, E-4749, E-4874, E-4884 and E-4904, were compared with that of ciprofloxacin and sparfloxacin against 1106 clinical isolates. Against majority of Enterobacteriaceae, general antibacterial activities of E-4749 (MIC90s 0.06-1 mg/L), E-4874 (MIC90s, 0.03-0.25 mg/L) and E-4884 (MIC90s 0.01-0.5 mg/L) were comparable or slightly lower than those of ciproloxacin (MIC90s 0.01-0.25 mg/L) and sparfloxacin (MIC90s 0.01-1 mg/L). The activity of E-4904 (MIC90s 0.06-2 mg/L) was lower than those of its analogues. Most of the Escherichia coli which were resistant to ciprofloxacin (MIC > or = 2 mg/L) and Serratia spp., were resistant to the new fluoroquinolones. beta-Lactamase producing strains of Moraxella catarrhalis were very susceptible to these compounds (MICs < or = 0.008 mg/L). Most of Pseudomonas aeruginosa, non-aeruginosa Pseudomonas spp., Xanthomonas maltophilia, and Acinetobacter spp. were resistant to the new quinolones (MIC90s 8- > 16 mg/L). On the contrary, these new antimicrobials were active against the majority of the Aeromonas spp. (MIC90s < or = 0.5 mg/L). E-4749, E-4874, E-4884 and E-4904 remained active (MIC90s < or = 0.25 mg/L) against Staphylococcus aureus strains susceptible to methicillin. However, its activity was two- to eight-fold lower than that of ciprofloxacin (MIC90 0.03 mg/L) and sparfloxacin (MIC90 0.06 mg/L). Against S. aureus resistant to methicillin or ciprofloxacin, activity of these new compounds and comparators agents, was very low (MIC90s 2- > 16 mg/L). Most of the strains of Enterococcus faecalis were resistant (MIC90s > 16 mg/L). The activity of E-4874, E-4904 and sparfloxacin (MIC90 1 mg/L for each one) was higher than that of the rest of the agents tested. E-4874 (MIC90 0.25 mg/L) was four-fold more active than the other antibacterials tested (MIC90 2 mg/L) against Listeria monocytogenes. No new quinolone was active against Bacteroides fragilis (MIC90s 4-16 mg/L), Bacteroides thetaiotaomicron (MIC90s 8- > 16 mg/L), and other B. fragilis group (MIC90s 16- > 16 mg/L). Ciprofloxacin (MIC90s > 16 mg/L), and sparfloxacin (MIC90s 8-16 mg/L) also were inactive. E-4874 (MIC90 4 mg/L) was the most active quinolone tested against B.fragilis.

Activity of BAY y 3118, a novel 4-quinolone, against Brucella melitensis.

We have tested the in-vitro activities of BAY y 3118, a new chlorofluoroquinolone, ciprofloxacin, sparfloxacin, streptomycin, tetracycline and rifampin against 59 strains of Brucella melitensis. BAY y 3118 (MIC90 0.12 mg/L) was twice as active as sparfloxacin and tetracycline (MIC90 0.25 mg/L). The activity of ciprofloxacin, rifampin and streptomycin (MIC90 0.5, 2, and 8 mg/L, respectively) was, respectively, four-, sixteen-, and more than sixty-fold lower than that of BAY y 3118.

Current status of bacterial resistance to third-generation cephalosporins.

A review of the evolution of bacterial resistance to third-generation cephalosporins is presented, focusing mainly on the prototypical member of this group-cefotaxime. Third-generation cephalosporins generally remain highly active against most Enterobacteriaceae, staphylococci, streptococci, Haemophilus, and Neisseriaceae. Only enterobacteria with a high frequency of mutant derepressed strains that hyperproduce chromosomally mediated beta-lactamase, Pseudomonas spp., and some glucose nonfermenter Gram-negative bacilli have demonstrated increased levels of resistance. The significance of derepressed strains and of the recently described extended-spectrum, plasmid-mediated beta-lactamases to the usefulness of the third-generation cephalosporins is discussed.

In-vitro activity of meropenem, a new carbapenem, against imipenem-resistant Pseudomonas aeruginosa and Xanthomonas maltophilia.

The activity of meropenem, a new carbapenem, as well as imipenem, ceftazidime, aztreonam, tobramycin, amikacin and ciprofloxacin against 18 strains of Xanthomonas maltophilia and 23 strains of Pseudomonas aeruginosa resistant to imipenem was tested. All strains of X. maltophilia were resistant to both penems. Ceftazidime, tobramycin and ciprofloxacin were the most active antimicrobial agents against this specie. 17% of imipenem-resistant strains of P. aeruginosa were sensitive to meropenem. Ciprofloxacin, amikacin and aztreonam were the most effective agents against these strains.

Antibiotic susceptibility profile of Xanthomonas maltophilia. In vitro activity of beta-lactam/beta-lactamase inhibitor combinations.

The susceptibility of 42 strains of Xanthomonas (Pseudomonas) maltophilia to 37 antibiotics (mainly beta-lactams, aminoglycosides, and fluorinated quinolones) was tested. Xanthomonas maltophilia was resistant to most beta-lactams, with ceftazidime, moxalactam, and ICI-194008 being the most active ones. Aminoglycosides had a very modest activity, with quinolones showing only moderate activity against this species. Trimethoprim/sufamethoxazole was effective against all strains tested. We also tested the synergy of several beta-lactam/beta-lactamase inhibitors against X. maltophilia. Only aztreonam/clavulanic acid at 3:1, 1:1 and, mainly, 2:1 combinations had synergistic activity, decreasing the rate of resistance from 92.8% for aztreonam alone to 32.4% for aztreonam-clavulanic acid at 1:1 and 0% for aztreonam-clavulanic acid at 2:1.

[Characteristics of Helicobacter (Campylobacter) pylori infection in our field]. / Características de la infección por Helicobacter (Campylobacter) pylori en nuestro medio.

The presence of helicobacter pylori in the stomach in patients with clinical signs of gastroduodenal disease and its possible relationship with several clinical, endoscopic and anatomopathologic characteristics of the illness were prospectively evaluated in 359 patients. H. pylori was isolated from 388 samples in 216 patients (60% of colonization). In patients with endoscopic and, or, anatomopathologic evidence of gastroduodenal alterations the microorganism was isolated in 67% of the instances whereas it was observed in only 7% of the patients free of such alterations (p less than 0.001). The prevalence was 100% in cases of bulboduodenitis, 77% in patients with peptic ulcer, 66% in cases of gastritis, and 20% in neoplastic patients. The colonization index for duodenal ulcer was 80% and that of gastric ulcer 70%. Among the cases with gastritis the highest index corresponde to the superficial chronic gastritis (82%). We failed to observe clinical signs that allowed to envisage the presence or absence of H. pylori in the gastric mucosa.

[Focal salmonellosis in Spain. Presentation of 14 cases and review of the literature]. / Salmonelosis focal en España. Presentación de 14 casos y revisión de la literatura.

A study of the 14 focal salmonelloses diagnosed in the Hospital Clínico Universitario from Salamanca during the last years is presented, along with a review of the major series reported in Spain. The most common focal salmonelloses were osteoarticular, representing one third of cases. The most common underlying condition was diabetes mellitus, which involved more than 40% of patients. The pathogenetical peculiarities of salmonellosis in these patients and their relation with the higher prevalence of focal salmonellosis in particular diseases are discussed.

[In vitro activity of 16 antimicrobial agents against Helicobacter (Campylobacter) pylori]. / Actividad in vitro de 16 antimicrobianos frente a Helicobacter (Campylobacter) pylori.

Campylobacter pylori has been associated with the etiology of gastritis and duodenal ulcer. It has been shown that several drugs, among them a variety of antimicrobials, eliminate C. pylori from gastric mucosa at least for a time, resulting in an improvement of the patients' symptoms. The activity of 16 antimicrobials (ampicillin, cefazolin, cefuroxime, cefotaxime, imipenem, aztreonam, tigemonam, erythromycin, vancomycin, nalidixic acid, colistin , norfloxacin, ciprofloxacin, difloxacin, ofloxacin and perfloxacin) was tested against 30 clinical isolates of C. pylori. The antimicrobials showing the highest activity were ampicillin, imipenem and ciprofloxacin, followed by cefazolin, cefuroxime, cefotaxime, aztreonam, tigemonam, erythromycin and difloxacin. Nalidixic acid, colistin and vancomycin were virtually ineffective against C. pylori.

In vitro activities of new oral beta-lactams and macrolides against Campylobacter pylori.

The in vitro activities of amoxicillin, cefuroxime, ceftetrame, cefetamet, cefixime, tigemonam, erythromycin, roxithromycin, and dirithromycin against 30 clinical isolates of Campylobacter pylori were determined by an agar dilution technique. Roxithromycin and amoxicillin (MICs for 90% of isolates tested, 0.01 and 0.06 micrograms/ml, respectively) were the most active antibiotics tested, but all strains were susceptible to all antimicrobial agents tested.