J.L. Muñoz Bellido

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

Abstract 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 acid, ciprofloxacin, 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%). Enterococcus spp. (4.7% vs. 6.8%)Streptococcus agalactiae (1.7% vs.3.1%) and Staphylococcus 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.

In vitro activity of 79 antimicrobial agents against Corynebacterium group D2.

Corynebacterium group D2 (CGD2) is involved in urinary tract infections in patients with underlying predisposing factors. This microorganism is highly resistant to a number of antimicrobial agents. We tested the activities of 79 antimicrobial agents against CGD2. beta-Lactams, aminoglycosides, and macrolides were ineffective. Fluorinated quinolones showed irregular activities, ofloxacin being the most active one. Doxycycline, rifampin, and mainly glycopeptides (vancomycin and teicoplanin) were the most active antibiotics against CGD2.

In vitro activities of new macrolides and rifapentine against Brucella spp.

We have tested the in vitro activities of streptomycin, rifampin, tetracyclines, trimethoprim-sulfamethoxazole, erythromycin, four new macrolides (roxithromycin, azithromycin, clarithromycin, and dirithromycin), and rifapentine against 62 strains of Brucella spp. Azithromycin and clarithromycin were, respectively, eight- and twofold more active than erythromycins (MIC for 90% of strains = 2, 8, and 16 micrograms/ml, respectively). The activity of rifapentine was similar to that of rifampin (MIC for 90% of strains = 1 microgram/ml).

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.

In vitro activity of newer antibiotics against Corynebacterium jeikeium, Corynebacterium amycolatum and Corynebacterium urealyticum

Abstract The in vitro activity of ciprofloxacin, erythromycin, telithromycin, teicoplanin, linezolid and quinupristin–dalfopristin was tested against human derived pathogenic corynebacteria. The MICs of these antibiotics were measured using the agar dilution method against 31 strains of Corynebacterium jeikeium , 58 Corynebacterium amycolatum (including 33 multidrug-resistant strains) and 64 Corynebacterium urealyticum clinical strains. A high resistance rate to ciprofloxacin and erythromycin was found in the three species. Telithromycin was much more active than erythromycin (MIC 90 of erythromycin ≥128 mg/l for all three species; MIC 90 of telithromycin: 4 mg/l for C. jeikeium , 64 mg/l for C. amycolatum and 1 mg/l for C. urealyticum ). There were no teicoplanin-resistant (MIC 90 1, 0.5 and 1 mg/l, respectively) or linezolid-resistant strains (MIC 90 1, 0.2 and 0.5 mg/l, respectively). Quinupristin–dalfopristin was active against most strains with an activity similar to linezolid, but three C. jeikeium and one C. amycolatum showed MICs ≥4 mg/l. Telithromycin showed much better activity against corynebacteria than older macrolides. Synercid and linezolid were active against most isolates tested, including multidrug resistant strains.

In vitro activity of linezolid, synercid and telithromcin against genetically defined high level fluoroquinolone-resistant methicillin-resistant Staphylococcus aureus

The in vitro activity of levofloxacin, moxifloxacin, gatifloxacin, erythromycin, telithromycin, linezolid, synercid and vancomycin was measured against 36 genetically defined, gyrA/grlA double mutant MRSA clinical strains with an MIC to ciprofloxacin > or = 8 mg/l. The three newer fluoroquinolones tested were more active than ciprofloxacin. Resistance rates for levofloxacin and gatifloxacin were high (44.5 and 36.1%, respectively). All the strains were moxifloxacin-susceptible, though most of them had MICs close to the break point. All the strains were intermediate or resistant to erythromycin and most were also resistant to telithromycin. No strains were resistant to linezolid, synercid or vancomycin (MIC(90): 2, 1 and 2 mg/l, respectively).

Effect of transferrin concentration on bacterial growth in human ascitic fluid from cirrhotic and neoplastic patients.

Abstract. Cirrhotic patients with ascites have an unusually high frequency of development of spontaneous bacterial peritonitis. Iron availability is a key factor in bacterial growth and the ability of the host to limit it is associated with resistance to infection. The present study was undertaken to evaluate the influence of iron and transferrin on bacterial growth in ascitic fluid from 25 biopsy‐proven cirrhotic and nine neoplastic carcinomatous patients. No significant differences were found when comparing total ascitic fluid iron between the two groups but ascitic fluid transferrin concentration was significantly lower in cirrhotic (29.26 mg dl‐1 SD 29.58) than neoplastic (96.57 mg dl‐1 SD 76.01) patients. Moreover, a significant negative correlation was found between bacterial growth and transferrin concentration in ascitic fluid (P = 0.039). When the iron concentration in ascitic fluid was experimentally elevated (50 μg dl‐1 or 150 μg dl‐1) we observed a progressive increase in bacterial growth. If transferrin concentration is simultaneously elevated (250 mg dl‐1) this increase does not occur. These findings indicate that the transferrin level is an important factor in the regulation of bacterial growth in ascitic fluid and that the low concentration found in cirrhotic patients could facilitate spontaneous bacterial peritonitis.

Oral cephalosporins: current perspectives

Oral cephalosporins had been, for years, a small group of compounds belonging to the first or second-generation cephalosporins, with a limited antimicrobial spectrum. New oral first-generation cephalosporins include cefprozil and loracarbef, similar to cefadroxil and cefaclor, respectively, with activity similar to cefaclor but with pharmacokinetic improvements. Second-generation oral cephalosporins are esters of already available cephalosporins, and third-generation oral cephalosporins include a number of drugs whose activity is similar to available parenteral drugs, showing pharmacokinetic advantages and, some of them, better resistance to hydrolysis mediated by extended wide-spectrum beta-lactamases. They may be a good alternative against mild to moderate ENT infections, UTIs, STDs, lower respiratory tract and skin and soft tissue infections, mainly in the outpatient setting.

The role of fluoroquinolones in respiratory tract infections: community acquired pneumonia

Newer fluoroquinolones may play an important role in the management of community acquired pneumonia. They retain activity similar to older fluoroquinolones against Gram-negative bacteria and are significantly more active against Gram-positive bacteria, especially pneumococci. They are also active against bacteria causing atypical pneumonia, penicillin-sensitive and -resistant and macrolide-sensitive and -resistant pneumococci and against beta-lactamase producing and non-producing Haemophilus influenzae. They have similar or slightly lower activity than ciprofloxacin against other Gram-negative organisms. They have rapid bactericidal activity and attain good lung tissue levels. Clinical studies show results similar or better than older treatments. Their impact on ecology and resistance remains to be elucidated but data on side effects and toxicity must be carefully evaluated.

Extrapulmonary tuberculosis in a University Hospital in Spain

Pulmonary tuberculosis in Europe has been decreasing over the last decades. This study evaluates the current importance of extrapulmonary tuberculosis and its trend over the last 10 years. In a University Hospital in Spain, 20% of all bacteriologically confirmed tuberculosis cases were extrapulmonary. The most frequent site was the urinary tract (73.5%). Ziehl-Neelsen staining was positive in 50.6% of the cases. Lowenstein-Jensen cultures became positive, on average, after 4.6 ± 1.4 weeks. The proportion of extrapulmonary tuberculosis among the total number of tuberculosis cases has steadily increased trend over the period of observation.