Normal values of combinational elastography in adult liver: the influence of age.

PURPOSE: We aimed to clarify the normal values obtained by simultaneous use of shear wave imaging and strain imaging (combinational elastography) in liver and reveal how aging influences them. METHODS: In our checkup center, 257 examinees were diagnosed with normal liver based on questionnaires about liver disease and their drinking history, liver function test results, and ultrasound B-mode study findings. We estimated the values of combinational elastography and considered the correlation between the values and age. A multivariate analysis was performed concerning several features and the liver fibrosis (LF) index. We divided examinees into a younger group (< 65 years old) and an older group (≥ 65 years old), and assessed the effect of age on the LF index. RESULTS: The mean shear wave velocity (Vs) of shear wave measurement (SWM) was 1.10 ± 0.17 m/s (range 0.84-1.93), and the mean LF index of real-time tissue elastography (RTE) was 1.371 ± 0.458 (range 0.258-3.173). There was no significant correlation between Vs and age. However, the LF index increased significantly with age. The multivariate analysis showed that age (P < 0.001) and BMI (P < 0.05) significantly affected the LF index. Indeed, the LF index in the older group was significantly higher than that in the younger group (P < 0.001). CONCLUSION: In adult liver, the normal Vs of SWM was 1.10 ± 0.17 m/s, and the normal LF index of RTE was 1.371 ± 0.458. The LF index increased significantly with age in contrast to Vs; therefore, the influence of age should be considered when using combinational elastography.

[A case of lung abscess due to Aspergillus viridinutans in a patient with aplastic anemia].

A 75-year-old woman with aplastic anemia was admitted to our university hospital because of a dry cough that had persisted for a month. Chest computed tomography showed a mass shadow with a central low attenuation area in the lower lobe of the left lung. Filamentous fungus resembling Aspergillus fumigatus was cultured from the specimens obtained by transthoracic needle aspiration biopsy and bronchoalveolar lavage. The initial diagnosis was a lung abscess due to A. fumigatus, although the patient did not respond well to antifungal agents. Subsequently, the filamentous fungus was identified as Aspergillus viridinutans by sequence analysis of the ß-tubulin gene, and the patient was successfully treated with combination therapy along with granulocyte colony-stimulating factor. The incidence of A. viridinutans infection is very rare. A. viridinutans is morphologically similar to A. fumigatus; however, the response to antifungal agents is generally worse than that observed in A. fumigatus infections. Therefore, the selection of agents and supplemental therapy is of vital importance in cases of A. viridinutans infection.

Positive Predictive Value of True Bacteremia according to the Number of Positive Culture Sets in Adult Patients.

BACKGROUND: Performing multiple blood culture sets simultaneously is a standard blood culture methodology, although it is often difficult to distinguish true bacteremia from contamination when only one of several blood culture sets is positive. This study clarified the relationship between the number of positive blood culture sets and clinical significance in patients with positive blood culture. METHODS: Patients aged 18 years and over with at least 1 positive blood culture were enrolled. Positive blood culture episodes were categorized from clinical records as true bacteremia, contamination, or unknown clinical significance. The associations among episodes of true bacteremia, isolated bacteria, the number of positive blood culture sets from among the performed sets, and the clinical background of patients were analyzed. RESULTS: Among a total of 407 episodes, 262, 67 and 78 were true bacteremia, contamination and unknown clinical significance, respectively. The positive predictive values (PPVs) of 1 out of 1, 1 out of 2 and 2 out of 2 positive sets in cases of Staphylococcus aureus, were 81.3%, 50% and 100% respectively; those in cases of coagulase-negative Staphylococci were 20.5%, 10.8% and 63.5%, respectively. Almost all cases of Escherichia coli, Pseudomonas aeruginosa, Klebsiella species and Candida species were true bacteremia. The probability of true bacteremia was strongly associated with recent surgery in multivariate analysis (P < 0.05). CONCLUSION: The probability of true bacteremia based on the number of positive culture sets from among the performed sets varies by microorganism. Therefore, PPVs calculated using this method may help physicians distinguish true bacteremia from contamination.

Bloodstream infection caused by Campylobacter lari.

We describe a case of bloodstream infection (BSI) caused by Campylobacter lari in a 58-year-old man diagnosed with lumbar pyogenic spondylitis. Anaerobic blood cultures, taken on the day of admission and on hospital day 4, were positive after 30 h of incubation, although no bacteria were detected by Gram staining. After subculture on 5 % sheep blood agar for 2 days at 35 °C in a 5 % CO2 environment, capnophilic, curved, gram-negative bacteria were recovered. The bacteria were identified as C. lari using a combination of phenotypic identification methods and partial 16S rRNA gene sequencing. The BSI was eradicated following combination therapy with intravenous tazobactam/piperacillin, oral erythromycin, and sulfamethoxazole/trimethoprim. These results suggest that accurate identification, to the species level, is important to determine effective treatment of BSI caused by Campylobacter spp. and can help us to understand the epidemiology.

Measurement of Pseudomonas aeruginosa multidrug efflux pumps by quantitative real-time polymerase chain reaction.

Multidrug efflux pumps contribute to multiple antibiotic resistance in Pseudomonas aeruginosa. Pump expression usually has been quantified by Western blotting. Quantitative real-time polymerase chain reaction has been developed to measure mRNA expression for genes of interest. Whether this method correlates with pump protein quantities is unclear. We devised a real-time PCR for mRNA expression of MexAB-OprM and MexXY-OprM multidrug efflux pumps. In laboratory strains differing in MexB and MexY expression and in several clinical isolates, protein and mRNA expression correlated well. Quantitative real-time PCR should be a useful alternative in quantitating expression of multidrug efflux pumps by P. aeruginosa isolates in clinical laboratories.

The indirect pathogenicity of Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia has at least two inducible beta-lactamases, L1 and L2, which can hydrolyze almost all classes of beta-lactam antimicrobial agents. This study was done to verify the indirect pathogenicity of S. maltophilia that could promote the growth of other beta-lactam agent-susceptible bacteria in a mixed culture. We counted CFU of beta-lactam agent-susceptible bacteria under the presence of imipenem or ceftazidime in a pure culture and mixed culture with S. maltophilia. Our results showed that beta-lactamase leaking from S. maltophilia can encourage the growth of Serratia marcescens and Pseudomonas aeruginosa even if imipenem or ceftazidime was supplemented. This study discovered a blind spot in chemotherapy against an indirect pathogen such as S. maltophilia.

First Streptococcus agalactiae isolates highly resistant to quinolones, with point mutations in gyrA and parC.

Three isolates of Streptococcus agalactiae highly resistant to multiple fluoroquinolones were isolated in Japan. Compared with susceptible strains of S. agalactiae, these quinolone-resistant strains had double point mutations within the quinolone resistance-determining regions of gyrA and parC; Ser-81 was changed to Leu (TCA --> TTA) in the amino acid sequence deduced from gyrA, and Ser-79 was changed to Phe (TCC --> TTC) in the amino acid sequence deduced from parC. Comparative sequence analysis revealed the possibility of gene transfer between S. agalactiae and another beta-hemolytic streptococcus, Streptococcus difficile.

[The results of antibiotic susceptibility of gram-negative rods at Tottori University Hospital--the possibility of the sensible use of narrow-spectrum antimicrobial agents].

The control of hospital-acquired infections is a matter of social concern, especially in the proper use of antimicrobial agents. The fundamentals of treatment for infectious diseases involve the exact identification of the responsible bacteria, and the minimum essential use of narrow-spectrum antimicrobial agents for the identified bacteria. We tested the antimicrobial susceptibility of 13 species which belong to the gram-negative rod type and isolated 50 or more strains at Tottori University Hospital in 2001. We evaluated the susceptibility pattern for every species, and have proposed a plan for the sensible use of narrow-spectrum antimicrobial agents. The resistant frequency in the present study was equal to or lower than previously reported. We think that it is possible to use narrow-spectrum antimicrobial agents more often, because the susceptible frequency to these agents was fairly high for some species. It is not too much to say that the history of the development of antimicrobial agents has been a road to broad-spectrum. Though the proper use of antimicrobial agents seems to go against this view, we should remain farsighted. Not only is the publicity of proper use indispensable but excellent surveillance is also highly necessary. We hope for the establishment of a good surveillance system gifted with simplicity, universality, high reproduction and continuity.