Average Isolation Rate Research Articles

A survey of Listeria monocytogenes strains, isolated from ready-to-eat foods in Israel over a period of 10 years, 1998–2007

Between 1998 and 2007 the food-control laboratories in Israel tested 10,413 samples from five groups of RTE foods: salads/dips, dairy, fish, poultry and meat. A total of 1260 isolates of Listeria monocytogenes were identified and submitted to the reference listeria laboratory. The average isolation rate was 12.1% with the highest prevalence being registered in poultry (27%). The serological results showed the prevalence of Lineage I, followed by Lineages II and III. The report revealed a high isolation rate of L. monocytogenes in certain RTE foods in spite of the existing zero tolerance policy.

Pathogens distribution and drug sensitivity of infantile dacryocystitis

To investigate the pathogens and drug tolerance of infantile dacryocystitis in order to provide evidence for clinical drug use. 230 cases of infant dacryocystitis (aged from 2 to 10 months, average 90 days) were analyzed for bacterial culture and drug sensitivity tests. These tests were performed following National Guide to Clinical Laboratory Procedures. Based on the results, analyzed the difference of pathogens in different year, the pathogens kind of dacryocystitis, main pathogens of infantile dacryocystitis, average isolation rate of pathogens and sensitive or resistance drug for pathogens. Average detecting rate was 87.0% (200 cases). There is no difference for detecting rate in each year. The pathogens were predominantly gram-positive coccus 74.5% (149 cases), coagulase-negative staphylococcus 20.5% (41 cases) and staphylococcus aureus 11.0% (22 cases). Majority of these bacteria were sensitive to tobramycin, ciprofloxacin and levofloxacin. Gram-positive coccus was sensitive to tobramycin and levofloxacin. For gram-negative rod, tobramycin and chloromycetin were most sensitive drug. The sensitivity rates were 96.67% (29 cases). The resistant rates to erythromycin and penicillin were 66.67% (20 cases) and 80.00% (24 cases). Coagulase-negative staphylococcus was the main pathogen of infantile dacryocystitis.

Epidemiological surveillance ofCampylobacter jejuniin chicken, dairy cattle and diarrhoea patients

Campylobacter jejuni of different subtypes were identified in chicken, dairy cattle and diarrhoea patients in China from 2005 to 2006, using multiplex PCR and RFLP. The results indicated that, of the three types of samples, C. jejuni was most frequently detected in poultry of the three types of samples, with an average isolation rate of up to 18.61% and a flock contamination rate of 86.67%. The average incidence of C. jejuni in overall cattle and environmental samples, milk cows, heifers and diarrhoea patients was 7.77, 5.02, 8.70 and 4.84%, respectively. A higher prevalence was detected in outpatients than ward patients (P<0.01), and in patients aged <7 years than in older patients (P<0.01). The 265 isolates of C. jejuni were classified into 20 distinct types by PCR-RFLP analysis of the flaA gene, with the genotype distribution in humans overlapping that in poultry and cattle. This suggests that certain C. jejuni strains circulate between humans and domestic animals such as cattle and poultry.

Respiratory syncytial virus: a sleeping giant?

The study by Jansen et al. 1 in the present issue of the European Respiratory Journal focuses on the impact of influenza and respiratory syncytial virus (RSV) on mortality and hospital admissions. As in many other similar publications, it emphasises the significance of RSV (and influenza) in all age groups and not just children, in whom the impact is already well recognised 1. In common with other similar studies, the evidence presented is derived by linking independent data on virus circulation (mainly from specimens sampled in children) with data on healthcare utilisation. As such, it falls short of direct linkage between cause and effect, although this has been demonstrated in experimental studies, which have included wild-type virus in addition to low temperature attenuated strains. In one of these studies, McKay et al. 2 administered wild-type virus to 20 human volunteers, and nine of them developed upper respiratory tract symptoms. In community-based observational cohort studies between 1977 and 1981, Monto and Sullivan 3 demonstrated average RSV isolation rates of 56 per 100 person-yrs in children aged 0–4 yrs, seven in those aged 5–19 yrs and somewhat less in older people. RSV demonstrated a clearer seasonality than other viruses studied. Zambon et al . 4 identified RSV in nose/throat virology specimens from community-based persons of all ages with influenza-like illness. Several studies have shown high rates of laboratory-confirmed infection in older people and especially in persons with chronic respiratory disease 5, 6. Basing their findings on serological studies, Dowell et al. 5 considered RSV to be one of the four most common pathogens identified in cases of lower respiratory tract infection in hospitalised adults, but went on to comment that none of the 57 cases of RSV infection included in the study were diagnosed during their period of hospitalisation. In an excellent …

어패류에서 분리한 장염비브리오균의 분포 및 항균제 감수성

Vibrio parahaemolyticus was investigated for analysis of distribution and antibiotic susceptibility at the markets, Seoul in 2004. The average isolation rate was 26.8%(306/1,143) and the highest rate with 64.9% was obtained in August. The isolation rates from December to April was 0.0%. It is more effective to inoculate into the enrichment medium, alkaline pepton water by swabbing a sample with a cotton ball rather than pouring mixed sample. The isolation rates were from 24.4% to 37.1% in domestic samples and from 9.8% to 26.8% in imported ones. All of the isolates were resistent to ampicillin and ticarcillin and most of them were sensitive to chloramphenicol, tetracycline, nalidixic acid, amoxicillin, ceftriaxone, streptomycin, kanamycin, trimethoprim/sulfamethoxazol, ampicillin/sulbactam, ciprofloxacin.

Development of a quantitative method for determination of the optimal conditions for protoplast isolation from cultured plant cells

An index [kv: average isolation rate of viable protoplast (number/ml min)] was established to evaluate the optimal conditions for protoplast isolation from cultured plant cells. The optimal conditions for protoplasts isolation from Nicotiana tabacum BY2 cultured cells could be determined on the basis of the kv [31.7 x 10(3) (number/ml min)]. The colony-forming efficiency of the protoplasts was about 46%. The optimal conditions for protoplasts isolation from Catharanthus roseus [kv = 38.1 x 10(3) (number/ml min)] and Wasabia japonica [kv = 14.2 x 10(3) (number/ml min)] cultured cells could also be determined. Furthermore, a method for rapid regenerating cell wall of protoplast in liquid culture using alginate gel containing locust bean gum was developed.

우리나라 참다래 저장병 발병율과 병원균

우리나라 참다래 주요 재배지인 전남과 경남 그리고 제주지역의 16개 포장에서 임의로 수집한 1600개 참다래 과실의 평균 저장병 발병율은 32.0%로 나타났지만, 저장병 발병율은 수확한 과수원에 따라서 5%에서 68%까지 다양했다. 저장병에 걸린 참다래 과실 중에서 15.4%가 외부 병징, 68.4%가 내부 병징을 나타내었고, 외부와 내부 모두에 병징을 나타내는 것은 16.2%였다. 저장병에 걸린 과실들에서 병원균의 검출율은 분리한 지역에 따라 차이가 있었으며, Botryosphaeria dothidea가 83.3%, Diaporthe actinidiae는 11.9%, Botrytis cinerea가 1.4%의 검출율을 보여 주요 저장병원균으로 밝혀졌다. 참다래 주요 저장병원균으로 확인된 B. dothidea와 D. actinidiae에 의해 발생하는 참다래 주요 저장병을 과실에 나타난 각 병징과 각 병원균들의 특성을 고려하여 과숙썩음병과 과실꼭지썩음병으로 각각 구분하여 명명하고자 한다. Sixteen hundred fruits were randomly collected from 16 kiwifruit (Actinidia deliciosa) orchards in Jeonnam, Gyeongnam and Jejn provinces in Korea in 2000 and incidences of postharvest fruit rots were examined. The overall disease incidence was 32% and varied much with locations of orchards ranging from 5 to 68%. The percentages of kiwifruits showing internal, external, and both internal and external symptoms were 21.9%, 4.9%, and 5.2%, respectively. Several fungi were isolated from rotten fruits; Botryosphaeria dothidea, Diaporthe actinidiae and Botrytis cinerea were the major pathogens with the average isolation rates of 83.3%, 11.9% and 1.4%, respectively. Based on the symptoms on kiwifruits and the characteristics, the postharvest fruit rots caused by B. dothidea and D. actinidiae are suggested to be named as ripe rots and stem-end rots, respectively.

Determination of serine/threonine protein phosphatase type 2B (PP2B) in lymphocytes by HPLC

Current cyclosporin (CsA) and tacrolimus (FK506) monitoring methods are based on blood concentrations determination, but the optimal sampling times are not clearly defined. An alternative pharmacodynamic approach has recently been introduced, based on assaying lymphocytes activity of calcineurin (PP2B), a phosphatase that is partially inhibited by CsA and FK506. However, the princeps method uses large amounts of radioactive [ 32 P] substrate, raising a number of safety issues. Here we describe an alternative method for PP2B activity determination, based on HPLC coupled with spectrophotometric detection. A 19-amino-acid peptide is phosphorylated by a protein kinase, and further dephosphorylated by lymphocyte PP2B in the presence of okadaic acid. The two peptides are separated by using reverse-phase chromatography with a detection wavelength of 205 nm. After lymphocyte isolation by density-gradient centrifugation, PP2B activity is derived from the dephosphorylated peptide concentration measured during the first 6 min of the enzymatic reaction. This technique gives reproducible results and good analytical sensitivity with 10 6 lymphocytes. With an average isolation rate of 59.6%, only 7 ml of blood is required, making the method suitable for lymphopenic patients. Moreover, PP2B activity is stable in blood samples kept for 24 h at room temperature and in isolated lymphocytes stored for 48 h at −20 °C. We validated the method by comparing median PP2B activity in 10 healthy volunteers (285.0±46.5 pmol /min/ 10 6 lymphocytes) and in 10 liver transplant patients (147.8±71.0 pmol /min/ 10 6 lymphocytes) ( p<0.001). The relation between calcineurin activity and tacrolimus blood concentrations was also studied.

Campylobacter isolation trends of cage versus floor broiler chickens: a one-year study

An experiment was carried out over a 1-yr period with broiler chickens to assess the influence of cage and floor rearing environments on the isolation trends of Campylobacter jejuni. The study used 36 7-wk-old broiler chickens that were raised in floor pens and naturally infected with or exposed to C. jejuni during the growout period. These broilers were then leg-banded and split into two groups with 18 per group. The groups were placed in wire cages or in a floor pen with unused litter in separate houses on the same farm. Each broiler was swabbed cloacally monthly to determine the presence of C. jejuni. The yearly average percentage isolation rates were significantly (P < 0.05) higher for the broilers held in the litter floor pen (130/185;66%) when compared to the broilers kept in wire cages (67/193;35%). There was a trend for higher isolation rates in the fall for caged and floor broilers and a decrease in rates near the end of the experimental year (summer) in the caged broilers. Isolation rates for both treatments reached their lowest level for the month of March. No caged broilers tested positive during the last 4 mo of the trial. The long-term cage isolation was linked to a reduced prevalence of C. jejuni. The results from this study suggest that housing environment and time spent in that environment play a major role in the continuing shedding and isolation of C. jejuni in broiler chickens.

Respiratory syncytial virus infection in children with acute respiratory infections in Zambia.

Epidemiological research on respiratory syncytial virus (RSV) infections in children was carried out at the Virology Laboratory, University Teaching Hospital (UTH), in Lusaka, Zambia, from January-December 1996. Specimens including 736 nasal washings and 2424 throat swabs were collected from children with acute respiratory infections (ARI) and tested for RSV by enzyme immunoassay and by virus isolation. RSV was isolated in 62 (4.1%) of 1496 throat swabs collected from March to September and was detected in 99 (16.3%) of 609 nasal washings from March to November. The average RSV isolation rate was 2.6% and the average RSV detection rate was 13.5%. The highest RSV isolation (8.1%) and detection (30.5%) rates were in June 1996. RSV antibody in the 278 serum specimens collected from Zambian children, who were hospitalized in the paediatric ward, UTH, was detected using a standard neutralization test. The antibody positive rate was 60-80% in children > 4 years. It is evident that RSV is one of the main causal agents of ARI in children in Zambia.

Isolation of mycobacteria from lymph nodes of pigs and their environment.

An attempt was made to isolate mycobacteria from the lymph nodes (LNs) of 459 pigs at four abattoirs (Obihiro, Tokachi-Shimizu, Fukagawa, and Kushiro). From 156 pigs selected at random at Tokachi-Shimizu highly contaminated with mycobacteria were isolated at 49% (29/59) in the submaxillary LN and 20% (13/65) in the mesenteric LN. The average isolation rates of mycobacteria from the lymph node in all the pigs, except those at Tokachi-Shimizu were as follows: 5.4% (16/294) from the submaxillary, 3.8% (11/293) from the pulmonary, and l.7% (5/298) from the mesenteric LN. When broken by the abattoir, they were 7% (7/100) at Fukagawa, 7.8% (8/102) at Kushiro, and 13.8% (14/101) at Obihiro. The average being 9.57% (29/303). It was found that 3 pigs harbored mycobacteria concurrently in two lymph nodes. A total of 76 strains of the mycobacterial isolates did not belonged to Mycobacterium tubercculosis or M. bovis, but a majority of them were so-called atypical mycobacteria. Of them, Runyon's Group III organisms were predominant and most of them identified as M. intracellulare serovars. M. avium serovar 1 was isolated from two pigs at Tokachi-Shimizu and Obihiro, respectively. This is the first isolation of M. avium in Hokkaido. From 202 environmental specimens collected, 17 strains of mycobacteria were isolated. It is known that the strains of serovars 4, 6, and 8 of M. intracellulare, which are potentially pathogenic for man and animals, have been isolated from soil, sewage and beddings. Isolation of M. intracellulare from soil, sewage and beddings is a new finding in Japan.

Mammals and scrub typhus ecology in peninsular Malaysia

The overall comparisons of habitats are given in (Table III). The habitats are arranged in order of extent of alterations by man, with the least disturbed at the top. The highest average blood isolation rates came from the least disturbed areas. The highest monthly maximal rickettsial isolation rates from blood and maximal prevalence rates of antibody per month were also obtained at Bukit Lanjan, the habitat least altered by activities of man. The lowest average blood isolation rate (6%) and the lowest monthly maximal rickettsial isolation and antibody prevalence rates were obtained at Bukit Mandol, the habitat most extensively and intensively altered by man. The intermediate habitats had intermediate rates. We caution anyone interpreting these observations, however, in terms of human disease, which seems to be associated with hyperendemic foci. Here we are not dealing with hyperendemicity from the standpoint of human disease, but present evidence of widespread endemicity from which hyperendemic foci may derive. Also, we have not yet identified the prevalent strains and do not know their infectivity to man.