Microbiología del agua mineromedicinal de los Balnearios de Alhama de Granada / Microbial diversity of the mineral water springs of Alhama de Granada Spa town

Se ha estudiado la diversidad microbiana del agua y de los tapetes microbianos de los manantiales Baño Árabe y Baño Nuevo del Balneario de Alhama de Granada (España). El número de microorganismos totales es alto (10 3 ml-1) y en su mayoría están vivos (93,2 por ciento). El número de bacterias heterótrofas aerobias y esporuladas ha sido inferior a 100 ufc por ml y corresponden a bacilos Gram positivos (49,1 por ciento), cocos Gram positivos (30,2 por ciento) y bacilos Gram negativos (20,7 por ciento), predominando los géneros Bacillus, Corynebacterium, Micrococcus, Staphylococcus, Pseudomonas y Stenotrophomonas. No se han encontrado indicadores fecales ni microorganismos patógenos. Los microorganismos proteolíticos, amilolíticos y amonificantes se han detectado en número medio (10 2-10 3/100 ml) y los nitrificantes, celulolíticos, halófilos y hongos en número bajo (menos de 10 2/100m1). En ambos manantiales se han encontrado bacterias sulfato reductoras y oxidantes del azufre y en el Baño Árabe bacterias fototrofas verdes y púrpuras. El tapete del "Baño Nuevo" está constituido por bacterias incoloras del azufre (Thiobacillus, Thiobacterium, Beggiatoa, Thiothrix). Los tapetes del Baño Árabe son complejos, formados por bacterias fototrofas verdes, cianobacterias, diatomeas, protozoos, bacterias quimiolitotrofas (Thiovulum, Achromatium), bacterias fototrofas púrpuras y bacterias sulfato reductoras (AU)

Heterotrophic bacterial populations in the mineral waters of thermal springs in Spain.

The microbiological quality and heterotrophic bacterial populations of 26 thermal mineral water springs in Spain were studied. In most of the springs the number of viable aerobes was less than 10(3) cfu ml-1 and the number of sporulated bacteria less than 10(2) cfu ml-1. No significant differences were found in the counts obtained with Plate Count Agar (PCA) and PCA diluted 1:10 and incubated at 22 degrees, 37 degrees and 45 degrees C. Total coliforms were found in 14 springs, faecal streptococci in three, spores of sulphite-reducing Clostridium and Pseudomonas aeruginosa in seven. Neither Escherichia coli nor Staphylococcus aureus were found. A total of 665 strains were isolated and 85.4% of these identified; 329 were Gram-positive and 239 were Gram-negative. The genera most prevalent present in the springs were Pseudomonas (in 92.3%), Bacillus (65.4%), Enterobacter, Micrococcus and Staphylococcus (50%), Acinetobacter (42.3%), Arthrobacter (38.4%), Clostridium (27%) and Xanthomonas (23%). Gram-negative bacteria predominated in the mesothermal springs and Gram-positive bacteria in the hyper- and hypothermal springs. The most common Gram-negative rod species isolated were Ps. fluorescens, Ps. aeruginosa, Ps. putida, Ent. agglomerans, Ent. sakazakii, Ac. calcoaceticus and Ent. amnigenus.

Resistance to the antimicrobial agents of bacteria isolated from non-sterile pharmaceuticals.

The in vitro antimicrobial resistance of 391 bacterial strains isolated from 389 samples of oral and topical medicaments was examined. The numbers of strains isolated (and percentage of samples that present them) were: 234 Bacillus (32.1%), 79 Staphylococcus (13.6%), 46 Micrococcus (11.3%), nine Pseudomonas (1.5%), eight Acinetobacter (1.5%), five Enterococcus (1.2%), three Alcaligenes (0.8%), two Escherichia and Enterobacter (0.5%), one each Providencia, Serratia and Streptococcus (0.2%). Gram-positive bacteria were isolated from topical and oral medicaments and Gram-negative rods were detected only in topical medicaments. The 97.4% of Bacillus strains were resistant to lincomycin and B. cereus was resistant to beta-lactam and trimethoprim-sulphamethoxazole. Staphylococcus spp. showed a high percentage of resistant strains to ampicillin (51.8%), tetracycline (40.5%) and trimethoprim-sulphamethoxazole (48.1%). Staphylococcus epidermidis had the highest number of multiresistant strains. The 23.9% of Micrococcus strains were resistant to colistin. Enterococcus and Streptococcus strains showed multiresistance to penicillin G, aminoglycosides and erythromycin. The 61.5% of Gram-negative rod strains showed multiresistance to beta-lactam antibiotics and erythromycin; Pseudomonas spp. were the most resistant.

Characterization of Bacillus cereus strains isolated from drugs and evaluation of their toxins.

The microbial contamination of 68 samples of topical and 324 samples of oral medicaments has been studied. The most common group of contaminants was members of the genus Bacillus (34.4%). Because of the pathogenic significance of B. cereus, 39 strains were characterized by morphology and biochemical properties. All except three showed most of the characteristics of the type strain. They were highly resistant to lincomycin, polymyxin B and penicillin G-cephalosporin and were susceptible to streptomycin, erythromycin and chloramphenicol. Enterotoxin, phospholipase C and haemolysin production were also studied: 33 strains gave a positive vascular permeability reaction, four of them causing necrosis, and 24 showed positive mouse lethal tests. All the strains had phospholipase activity. The majority also exhibited differing degrees of haemolysis. Permeability factor was related to mouse lethality and haemolytic activity. Phospholipase C was not related to any of the above activities.

Numerical taxonomy of Bacillus isolated from orally administered drugs.

Numerical taxonomy procedures were used to study 118 strains of Bacillus isolated from non-sterile drugs prepared for oral administration. Similarities between pairs of strains were calculated by the simple matching coefficient of Sokal and Michener (SSM). Each strain was tested for 60 unit characters and three clusters were defined. The strains in each cluster presented a similarity level of at least 60%. Cluster A comprised the strains identified as Bacillus cereus (SSM = 93.13%), cluster B contained three subgroups corresponding to the species B. pumilus, B. subtilis and B. licheniformis (SSM = 84.35%) and cluster C also included three subgroups that belonged to the species B. firmus, B. lentus and B. badius (SSM = 80.14%). The most discriminating tests were selected to differentiate the clusters from the subgroups. The feature with the highest discriminating power between clusters A and B was the lack of acid production from arabinose and mannitol. The Voges-Proskauer, methyl red tests and sensitivity to polymyxin B clearly distinguished cluster A from C. The Voges-Proskauer test and acid production from arabinose were the best to differentiate between B and C. Bacillus pumilus and B. subtilis differed in starch hydrolysis and B. licheniformis in growing anaerobically. To discriminate B. firmus from B. lentus the most important tests were the acid production from glucose and sucrose; intermediate strains were found. Bacillus badius was differentiated from B. firmus by 10 tests, and from B. lentus by the production of urease.