Streptococci species of anginosus group isolated from oral and maxillofacial infections

The aim of the study was to isolate and identify at species level streptococci strains of anginosus group in pus samples collected from 110 patients with oral and maxillofacial (OMF) infections. Gram-stained smears and cultures on selective and nonselective media were done from each of the 111 pus samples (2 samples were collected from one of the patients, who presented 2 oral abscesses at the same time). The isolates were identified on the basis of cultural and biochemical characteristics. Speciation of the anginosus group isolates was performed using the Rapid ID 32 Strep system (Bio Mérieux, France). Fourty-four anginosus group strains were isolated from 42 patients. Fourty of these isolates were identified as Streptococcus anginosus (2 nonidentical isolates were found in 2 patients), 3 isolates as Streptococcus constellatus and only one as Streptococcus intermedius. The study confirmed that the anginosus group is often involved in OMF infections alone or in association with other aerobic and/or anaerobic bacteria. In the investigated cases, Streptococcus anginosus was by far the most frequently isolated species within the anginosus group.     

Antibiotic susceptibility of bacterial strains isolated from patients with various infections

AIMS: Isolates from various samples obtained during 1998 and 1999 were identified and their susceptibility to third-generation cephalosporins, monobactams and/or cephamycins studied along with any production of ESBLs. METHODS AND RESULTS: Of these samples, bacteria most frequently isolated by the conventional techniques and Vitek GNI card were Escherichia coli (37%), Klebsiella pneumoniae (27%) and Enterobacter cloacae (16%). Using disk diffusion and double-disk synergy tests, we found that 71% strains produced ESBLs and 18% strains produced ESBLs and cephamycinases. Banding patterns of PCR amplification with the designed primers showed that 57% strains were capable of harbouring bla(SHV) genes. The bla(TEM), bla(CMY) and bla(AmpC) genes were harboured by 55%, 31% and 12% strains, respectively. Forty-five percent of strains contained more than two types of beta-lactamase genes. In particular, one strain contained bla(TEM), bla(SHV), bla(CMY) and bla(AmpC) genes. CONCLUSIONS: The percentage of ESBL-producing strains was high. The most prevalent beta-lactamase gene was bla(SHV) gene. The bla(CMY) genes have been prevalent in cephamycin-resistant strains. The multidrug-resistant strains resistant to third-generation cephalosporins and cephamycins were detected in high percentage. SIGNIFICANCE AND IMPACT OF THE STUDY: Resistance mechanisms to beta-lactams, comprising mostly extended-spectrum beta-lactamase (ESBL) production, lead to the resistance against even recently developed beta-lactams in enterobacteria, which is now a serious threat to antibiotic therapy. The high prevalence of bla(CMY) genes and multidrug-resistant genes may also cause therapeutic failure and lack of eradication of these strains by third-generation cephalosporins or cephamycins.     

Antimicrobial activities of some Bacillus spp. strains isolated from the soil

In this study a total of 29 Bacillus species isolated from the soil was analyzed using the agar diffusion method in terms of their general inhibition effects to some test bacteria. It has been found that isolates are effective against gram-positive and gram-negative bacteria whereas their extensive inhibition effect is particularly against gram-positive bacteria. On the other hand, B. cereus M15 strain has an inhibitory effect against both gram-positive and gram-negative bacteria. Furthermore some isolates are more effective against test bacteria when compared to some antibiotics.     

New serotype of mutans streptococci isolated from pig oral cavity

Gram-positive streptococcal mutans-like strains, but with clearly different colony formation than S. orisuis on Mitis Salivarius agar, were isolated from the pig oral cavity and identified by 16S rRNA sequencing, G+C content, DNA-DNA homology and extensive biochemical and serological testing. The phenotypic data showed that the strains were similar to S. orisuis except for susceptibility to bacitracin. DNA-DNA homology between the isolates and S. orisuis was 72∼81%. However, serological data showed that they have a different sero-specific antigen from S. orisuis and other mutans streptococci. A new serotype, designated p, strains are classified in a serovar of S. orisuis, one of mutans streptococci.     

Antimicrobial susceptibility of Francisella noatunensis subsp. noatunensis strains isolated from Atlantic cod Gadus morhua in Norway

A total of 30 isolates of Francisella noatunensis subsp. noatunensis isolated from Atlantic cod Gadus morhua L. were tested for susceptibility, in the form of minimal inhibitory concentration (MIC) values, against the following antibacterial agents: flumequine, oxolinic acid, ciprofloxacin, florfenicol, oxytetracycline, erythromycin, streptomycin sulphate, trimetoprim/sulphadiazine and rifampin. All the isolates had a low susceptibility to oxytetracycline, trimetoprim/sulphadiazine (Tribrissen?), erythromycin, ciprofloxacin and streptomycin with MIC values of 64, 64 to 128, 16, 8 and 32 to 128 μg ml-1, respectively. The strains were, on the other hand, susceptible to florfenicol, oxolinic acid, flumequine and rifampin with MIC values of 0.5, 0.25, 0.25 and 0.25 to 1 μg ml-1, respectively.     

Antimicrobial effect of Korean propolis against the mutans streptococci isolated from Korean

The aim of this study was to determine the optimal concentration of Korean propolis against clinical isolates of mutans streptococci (MS) from Koreans. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) and time-kill curves against mutans streptococci. The MIC(90) values of propolis for MS were 35 μg/ml. Propolis had a bacteriostatic effect on Streptococcus mutans ATCC 25175(T) and bactericidal effects on Streptococcus sobrinus ATCC 33478(T) at > 2 × MIC (70 μg/ml). These results suggest that the propolis can be used in the development of oral hygiene products for the prevention of dental caries.     

Comparison of some adhesive properties of Pseudomonas aeruginosa strains isolated from respiratory and urinary tract infections

The aim of the paper was the comparison of adhesive properties concerning pathogenic potential of P. aeruginosa strains isolated from the patients with respiratory tract infections and from the patients with urinary tract infections. It was stated that P. aeruginosa strains had no haemagglutinating properties when cultured on a solid medium. Bacteria cultured in a liquid medium showed an increase of these properties in 48 h cultures as compared with 24 h cultures. They were not sensitive to heating. The haemagglutinating properties of the most strains were inhibited by D-mannose. These results seem to suggest that in P. aeruginosa strains fimbriae play an important role in adhesion. On the other hand, the mechanism of adhesion is not uniform as shows mannose-sensitivity of some strains and its lack in the other haemagglutinating strains. The most effective agglutination of human erythrocytes seems to be caused by the species specificity of the individual strains isolated from humans. The higher attachment of P. aeruginosa strains isolated from the urinary tract infections than those from respiratory tract infections to "Vero" cells suggests that these two strains populations may differ in their pathogenic potential to various tissues.     

Antimicrobial susceptibility of staphylococci isolated from otitis externa in dogs

Samples were obtained from 65 unmedicated adult dogs, processed for isolation of Staphylococcus species and tested for susceptibility to penicillin G, gentamicin, oxacillin, tetracycline, trimethoprim-sulphamethoxazole, streptomycin, ampicillin and rifampin. Forty-four isolates were obtained, which represents 67.7% of samples. Coagulase-negative species were most commonly found, and the most frequently isolated staphylococcus species were Staph. epidermidis and Staph. aureus. Other species, such as Staph. simulans, Staph. haemolyticus, Staph. saprophyticus and Staph. intermedius were also isolated. Resistance to antibiotics was frequently observed, with 90.9% of the isolates showing resistance to at least one drug. The most active antimicrobial agents against staphylococci isolated from otitis externa of dogs were rifampin and oxacillin. Multidrug resistance was a common finding, and one strain of Staph. haemolyticus species, was resistant to all tested antimicrobial agents. Resistance to three or more different drugs was a common finding, observed in 16 strains (36.4%) of both coagulase-positive and coagulase-negative staphylococci. This study highlights the emergence of cases of otitis externa determined by coagulase-negative staphylococcus strains and once more emphasizes the need for bacterial culture with species identification and susceptibility testing of swab specimens from the ear canal in order to choose appropriate antimicrobial agents.     

Serologic and genetic analysis of group B streptococci isolated from adult patients

Serologic and genetic typing with RAPD (Random Amplified Polymorphic DNA) method was used for epidemiologic analysis of GBS. 125 strains isolated from various clinical samples from adult patients were tested. In serologic typing seven serotypes have been found. Serotypes III and R were the most often encountered, containing 37,6% and 20,8% of samples. There was no dependence between serologic type and disease process. Optimalisation of RAPD reaction parameters was based on the standard strains of GBS. In the group of strains tested with the use of RAPD method, eleven genetic profiles were found, with prevalence of profile B (25,8%). Five other profiles occured with similar frequency (8,8% - 12,8%). Among streptococci isolated from patients with the infection of genitourinary tract, great differentiation in the genetic profiles of the strains has been found. Each serologic type contained various genetic profiles. Genetic variety showed by RAPD method indicates the raised ability of this technique to find differences among isolates of GBS.     

Thermal susceptibility of Streptococcus faecium strains isolated from frankfurters

The heat resistance of nine strains of Streptococcus faecium isolated from frankfurters was determined at 63 and 68 degrees C in brain heart infusion broth. Exponential-phase cultures (approximately 10(7) colonies/mL) were used as inoculants. The heat resistance of S. faecium DP2181, a moderately resistant isolate, was further examined in broth (55, 63, and 68 degrees C) and frankfurter emulsion (63 and 68 degrees C). The decimal reduction times (D values) were determined by regression. In broth, both time-temperature combinations resulted in a 3-4 log decline in bacterial numbers for the nine S. faecium strains tested. For S. faecium DP2181, the survivor curves deviated from the logarithmic order of death at all three heating temperatures. An initial slow period of death was evident at 55 degrees C and a resistant tail of organisms was observed at 55, 63, and 68 degrees C. The D55D63, and, D68 values for the logarithmic portion of the corresponding survivor curves were 105.6, 9.36, and 3.34 min, respectively. The survival of DP2181 was enhanced by the frankfurter emulsion. The results indicate that populations of S. faecium existed that were very heat resistant and could survive normal frankfurter processing if initially present in high numbers.     

Antimicrobial potential of four Lactobacillus strains isolated from breast milk

AIMS: The antimicrobial potential of four lactobacilli (Lactobacillus salivarius CECT5713, Lactobacillus gasseri CECT5714, L. gasseri CECT5715 and Lactobacillus fermentum CECT5716), isolated from fresh human breast milk, was evaluated in this study and compared with Lactobacillus coryniformis CECT5711, a reuterin-producing strain isolated from an artisan goat's cheese. METHODS AND RESULTS: Agar diffusion tests, competitive adhesion assays and mucin expression assays were carried out in order to value the antibacterial properties of the lactobacilli strains. The antibacterial capability of the strains was tested in vivo by using a murine infection model with Salmonella choleraesuis. The results revealed that all the strains studied, displayed antibacterial properties against pathogenic bacteria. However, the antibacterial potential varied among the lactobacilli tested and, in fact, L. salivarius CECT5713 showed not only the best in vitro antibacterial activity, but also the highest protective effect against a Salmonella strain in the murine infection model. CONCLUSION: The four breast-milk lactobacilli, and particularly L. salivarius CECT5713, possess potent antibacterial activities that result in a higher protection against S. choleraesuis CECT4155 in a mouse infection model. SIGNIFICANCE AND IMPACT OF THE STUDY: These results suggest that lactobacilli from breast milk could contribute to an anti-infective protection in neonates and would be excellent candidates for the development of infant probiotic products.     

Antimicrobial susceptibility of microorganisms isolated from urine of pediatric ward patients

The study was an analysis of the frequency of urine bacterial isolation in hospitalized children as well as an evaluation of their susceptibility to antibiotics used in urinary tract infections (UTI). The analysis focused on microbiological urine tests carried out between January 2006 and December 2008. Altogether, 311 strains were obtained, of which E. coli (50.8%) and E. faecalis (13.5%) were the most frequently isolates. The highest percentage of Enterobacteriaceae were sensitive to ceftazidime (92%); to a lesser degree to amoxicillin/clavulanic acid (85%), to trimethoprim/sulfamethoxazole (84%), to nitrofurantoin (82%), to cefuroxime (81%), to cefalotin (66%) whereas only 24% were sensitive to ampicillin. ESBLs were produced by 8% of all Enterobacteriaceae strains. P. aeruginosa strains were totally sensitive to ceftazidime; over 90% - to piperacillin and aminoglycosides, and 77% to carbenicillin. Staphylococci manifested 100% sensitivity to nitrofurantoin. Only 20% of S. aureus were sensitive to trimethoprim/sulfamethoxazole and to trimethoprim; in the case of S. epidermidis: 83% and 67% respectively. No resistant strains were found among S. agalactiae and E. faecalis. E. faecium strains, in turn, were resistant to ampicillin and often to nitrofurantoin (64%), to vancomycin (VanB; 45%) and to high aminoglycoside concentrations (HLAR; 45%).