Salmonella isolation with Rappaport's medium after pre-enrichment in buffered peptone water using a series of inoculum ratios.

The ability of malachite green/magnesium chloride broth (Rappaport''s medium) to isolate salmonellas from 25 ml quantities of sewage-polluted natural water was investigated. Samples were first pre-enriched in buffered peptone water and varying volumes of inoculum from the pre-enrichment culture were inoculated into Rappaport''s broth. Inoculum ratios in the range 1:2000 to 1:10 were examined. The inoculum ratio denotes the ratio of the volume of inoculum to the volume of fluid medium into which it is introduced. Optimum results were obtained with the 1:2000 ratio, although the salmonella isolation rate was only slightly less with the 1:500 and 1:100 ratios. The 1:2000 inoculum ratio was obtained with a graduated loop holding approximately 0.005 ml of fluid. Use of a loop for inoculation has advantages in speed of performance and safety of manipulation.     

A comparisoin of the R25 modification of Rappaport s enrichment medium with strontium chloride B for salmonella isolation from sewage polluted natural water

The relation of salmonella isolation efficiency and the size of inoculum introduced from a buffered peptone water culture of sewage polluted water into strontium chloride B medium was investigated. Two separate studies were made, one using enrichment at 37 degrees C, the other at 43 degrees C. From these trials, two inocula suitable for efficient salmonella isolation were determined. Using this information, strontium chloride B medium was compared with modified Rappaport's broth (R25). The inoculum used with R25 was 0.005 ml, determined in an earlier study. Two incubation temperatures were employed with strontium chloride enrichment (37 and 43 degrees C). Rappaport's medium was incubated at 37 degrees C only. Elevated temperature enrichment at 43 degrees C improved the performance of strontium chloride B, but Rappaport's broth still gave significantly better results. This supports earlier studies on simplification of salmonella isolation and standardization of routine technique on a single enrichment medium: Rappaport broth (R25) incubated at 37 degrees C.     

Comparison of selenite F, Muller-Kauffmann tetrathionate and Rappaport's medium for the isolation of salmonellas from sewage-polluted natural water using a pre-enrichment technique.

Three enrichment broths, selenite F, Muller-Kauffmann tetrathionate and Rappaport, were examined for their efficiency in salmonella isolation. The three media, prepared from single ingredients in the laboratory, were compared with their commercial equivalents. Laboratory-prepared media were more efficient for isolating salmonellas from sewage-polluted natural water samples. A pre-enrichment stage using buffered peptone water was employed throughout the investigation. The size of inoculum from the pre-enrichment medium was relevant to successful salmonella isolation. Inocula studied were 1 ml and one loopful (3 mm diameter loop). The smaller inoculum gave better results with Rappaport, the larger with selenite and tetrathionate. Using the optimal inocula, Rappaport was the most efficient enrichment broth of the three fluid media in this study.     

Salmonella isolation with Rappaport-Vassiliadis enrichment medium seeded with different sized inocula of pre-enrichment cultures of meat products and sewage polluted water

A total of 574 samples, of seven different types, were examined for the presence of salmonellas. All the specimens were pre-enriched in buffered peptone water and enriched in Rappaport-Vassiliadis medium (RV medium). In one trial 0.1 ml of pre-enrichment culture of 497 samples (79 chicken carcasses, 228 specimens of minced meat, 100 pork sausages, 19 samples of dried powdered chicken meat, 11 specimens of faeces of healthy pigs and 60 samples of sewage polluted natural sea water) was seeded to 10 ml as well as to 100 ml of RV medium. With the first inoculum (ratio 0.1:10), 111 samples were found to contain salmonellas, while with the second inoculum (ratio 0.1:100), only 102 positive samples were detected. This difference is marginally significant (P less than 0.05). In another trial, 0.1 ml, 0.2 ml and 0.5 ml of pre-enrichment culture of 162 specimens (71 chicken carcasses, 40 samples of sewage polluted sea water and 51 samples of sewage polluted river water) were in turn introduced to 10 ml of RV medium. With the 0.1 ml inoculum 93 positive samples were detected, while with the 0.2 and 0.5 ml inocula 93 and 88 positive samples were found. The differences are not statistically significant. In these trials the growth of competing organisms was minimal with ratios of inocula 0.1:10 or 0.1:100.     

Salmonella isolation with Rappaport-Vassiliadis enrichment medium seeded with different sized inocula of pre-enrichment cultures of meat products and sewage polluted water.

A total of 574 samples, of seven different types, were examined for the presence of salmonellas. All the specimens were pre-enriched in buffered peptone water and enriched in Rappaport-Vassiliadis medium (RV medium). In one trial 0.1 ml of pre-enrichment culture of 497 samples (79 chicken carcasses, 228 specimens of minced meat, 100 pork sausages, 19 samples of dried powdered chicken meat, 11 specimens of faeces of healthy pigs and 60 samples of sewage polluted natural sea water) was seeded to 10 ml as well as to 100 ml of RV medium. With the first inoculum (ratio 0.1:10), 111 samples were found to contain salmonellas, while with the second inoculum (ratio 0.1:100), only 102 positive samples were detected. This difference is marginally significant (P less than 0.05). In another trial, 0.1 ml, 0.2 ml and 0.5 ml of pre-enrichment culture of 162 specimens (71 chicken carcasses, 40 samples of sewage polluted sea water and 51 samples of sewage polluted river water) were in turn introduced to 10 ml of RV medium. With the 0.1 ml inoculum 93 positive samples were detected, while with the 0.2 and 0.5 ml inocula 93 and 88 positive samples were found. The differences are not statistically significant. In these trials the growth of competing organisms was minimal with ratios of inocula 0.1:10 or 0.1:100.     

A comparisoin of the R25 modification of Rappaport s enrichment medium with strontium chloride B for salmonella isolation from sewage polluted natural water.

The relation of salmonella isolation efficiency and the size of inoculum introduced from a buffered peptone water culture of sewage polluted water into strontium chloride B medium was investigated. Two separate studies were made, one using enrichment at 37 degrees C, the other at 43 degrees C. From these trials, two inocula suitable for efficient salmonella isolation were determined. Using this information, strontium chloride B medium was compared with modified Rappaport''s broth (R25). The inoculum used with R25 was 0.005 ml, determined in an earlier study. Two incubation temperatures were employed with strontium chloride enrichment (37 and 43 degrees C). Rappaport''s medium was incubated at 37 degrees C only. Elevated temperature enrichment at 43 degrees C improved the performance of strontium chloride B, but Rappaport''s broth still gave significantly better results. This supports earlier studies on simplification of salmonella isolation and standardization of routine technique on a single enrichment medium: Rappaport broth (R25) incubated at 37 degrees C.     

A comparison of two modifications of Rappaport's enrichment medium (R25 and RV) for the isolation of salmonellas from sewage polluted natural water

The development of Rappaport's enrichment medium and elevated temperature incubation as methods of salmonella isolation is traced. The recent recording of a merger of the two techniques by means of Rappaport--Vassiliadis medium is noted (RV medium). In Cardiff, we have found an earlier modification of Rappaport's enrichment (R25) by Vassiliadis to be efficient in salmonella recovery from environment samples. The current study compares the two media using sewage polluted natural water as test material. Under the conditions of experiment, R25 was more successful in salmonella isolation than RV, although the later medium inhibited competitive organisms better. R25 is a convenient enrichment broth for routine use. In combination with pre-enrichment it allows the use of a loop for subculture rather than a pipette. This increases safe manipulation. It also produces a high proportion of positive isolations at the 24 h subculture time in contrast to other enrichment broths. For these reasons it forms an integral part of salmonella isolation methodology in our laboratory.     

A comparison of enrichment media for the isolation of salmonellae from seagull cloacal swabs

The relative efficiency of three selective enrichment broths (Muller-Kauffmann tetrathionate. Rappaport's and selenite F) was investigated for the isolation of salmonellae from seagull cloacal swabs. Pre-enrichment in buffered peptone water was employed throughout the study, which involved the examination of 560 gulls, sixty (10.7%) of which were found to be carrying salmonellae. Rappaport's broth as modified by Vassiliadis for incubation at 43 degrees C (Vassiliadis et al. 1976) yielded the highest number of positive swabs (57) and the widest range of serotypes. It was significantly more efficient that either selenite F or tetrathionate broth, although the results obtained with Rappaport's broth incubated at 37 and 43 degrees C did not differ significantly (P greater than 0.5). Eleven serotypes were isolated during the study, the most prevalent being Salmonella virchow.     

Comparison of selenite F, Muller-Kauffmann tetrathionate and Rappaport's medium for salmonella isolation from chicken giblets after pre-enrichment in buffered peptone water.

Six hundred and eighty three samples of chicken giblets were examined for salmonellas. Three hundred and forty nine of these were neck and crop specimens and 224 were combined liver and heart samples. Two hundred and ten, in all, contained salmonellas. The technique of examination included pre-enrichment in buffered peptone water at 37 degrees C for 18 h and subculture to three enrichment media: Muller-Kauffmann tetrathionate, selenite F and Rappaport''s magnesium chloride malachite green broth. Inocula from buffered peptone water to 10 ml of tetrathionate and selenite were 1 ml in each case. The inoculum from the pre-enrichment medium to 10 ml of Rappaport was 0.005 ml. Tetrathionate and selenite were incubated at 43 degrees C for 48 h. Rappaport''s medium was incubated at 37 degrees C for 48 h. Subcultures from all three enrichment broths were made at 24 h and 48 h to brilliant green MacConkey agar. Selective agars were incubated at 37 degrees C for 24 h. The most successful technique for salmonella isolation used Rappaport''s medium, which was significantly more efficient than either tetrathionate or selenite. This finding reinforces results obtained using sewage polluted natural water as test material and it is suggested that routine examination of environment samples for salmonellas could be based on Rappaport''s medium alone. If S. typhi, S. dublin or subgenus III salmonellas were likely to be present in the sample, the technique described here would require modification.     

Isolation of Salmonella with the use of 100 ml of the R10 modification of Rappaport's enrichment medium.

One hundred and eighty samples of pork sausages were examined after pre-enrichment in buffered peptone water (P medium), for the presence of salmonellas. From each pre-enrichment four enrichments were made: (1) o.1 ml of P medium was inoculated into 10 ml of Rappaport''s medium formula R 10 (R 10/43 degrees C), /2) 1 ml of the P medium was added to 100 ml of R10 broth (R10/100 ml/43 degrees C), (3) 1 ml of P medium was inoculated into 10 ml of Muller-Kauffmann tetrathionate broth (MK medium) prepared in accordance with the International Standards Organization document ISO 3565 (MK/43 degrees C) and (4) 10 ml of P medium were added to 100 ml of MK broth (MK/100 ml/43 degrees C). All the enrichments were incubated at 43 degrees C for 48 h. Forty-six and 47 samples were found positive with the first two enrichment methods (R10/43 degrees C and R10/100 ml/43 degrees C), while only 16 samples were found positive with the method MK/43 degrees C, and 27 with the methods MK/100ml/43 degrees C. The superiority of either one of the two R10 procedures over either one of the two MK methods is statistically highly significant (paired Chi2; P less than 0.001 in all four comparisons). The superiority of procedures MK/100 ml/43 degrees C over the method MK/43 degrees C is also statistically significant (P less than 0.005). Both R10/43 degrees C and R10/100 ml/43 degrees C procedures had a much stronger inhibitory effect on the competing organisms (lactose- and sucrose negative) than the two MK methods.     

Giardia duodenalis: enhanced growth in cell culture

Growth of Giardia duodenalis in broth and in animals has been studied in considerable detail. In contrast, the kinetics of growth in cell culture have been little evaluated. In this study, in vitro growth of G. duodenalis was evaluated in cell culture, primarily using mouse McCoy cells in vials. The media used were Giardia broth (TYI-G), Trichomonas vaginalis broth (TYI-T), and standard cell culture media (CMGA) alone and in combination (2 parts by volume CMGA to one part of TYI broth). Addition of cell culture enhanced the sensitivity of the systems in detecting low numbers of G. duodenalis. Growth was identified consistently with inocula less than or equal to 10/ml, and often with a calculated 10-1/ml inoculum with CMGA/TYI-T and CMGA/TYI-G with cells, and with TYI-G with and without cells. The 2 preferred systems for sensitivity and growth were CMGA/TYI-G with cells and TYI-G with cells. The pH fell minimally in the growth systems and, if CMGA was in the media, cell monolayers remained intact and viable throughout the experiment. In preliminary experiments, cell cultures did not allow growth of one strain of G. muris. These cell culture systems may be useful for detection of low numbers of non-laboratory adapted trophozoites, and should be useful in evaluating the interaction of G. dudodenalis with cells in culture.     

Continuous nasogastric tube feeding: monitoring by combined use of refractometry and traditional gastric residual volumes

BACKGROUND & AIMS: Traditional use of gastric residual volumes (GRVs) is insensitive and cannot distinguish retained enteral formula from the large volume of endogenous secretions. We designed this prospective study to determine whether refractometry and Brix value (BV) measurements could be used to monitor gastric emptying and tolerance in patients receiving continuous enteral feeding. METHODS: Thirty-six patients on continuous nasogastric tube feeding were divided into two groups; patients with lower GRVs (<75 ml) in Group 1, patients with higher GRVs (>75 ml) in Group 2. Upon entry, all gastric contents were aspirated, the volume was recorded (Asp GRV), BV measurements were made by refractometry, and then the contents were reinstilled but diluted with 30 ml additional water. Finally, a small amount was reaspirated and repeat BV measurements were made. Three hours later, the entire procedure was repeated a second time. The BV ratio, calculated (Cal) GRV, and volume of formula remaining were calculated by derived equations. RESULTS: Mean BV ratios were significantly higher for those patients in Group 2 compared to those in Group 1. All but one of the 22 patients (95%) in Group 1 had a volume of formula remaining in the stomach estimated on both measurements to be less than the hourly infusion rate (all these patients had BV ratios <70%). In contrast, six of the 14 patients in Group 2 (43%) on both measurements were estimated to have volumes of formula remaining that were greater than the hourly infusion rate (all these patients had BV ratios >70%). Three of the Group 2 patients (21%) whose initial measurement showed evidence for retention of formula, improved on repeat follow-up measurement assuring adequate gastric emptying. The remaining five patients from Group 2 (35%) had a volume of formula remaining that was less than the hourly infusion rate on both measurements. The pattern of Asp GRVs and serial pre- and post-dilution BVs failed to differentiate these patients in Group 2 with potential emptying problems from those with sufficient gastric emptying. CONCLUSIONS: Refractometry and measurement of the BV may improve the clinical utilization of GRVs, by its ability to identify the component of formula within gastric contents and track changes in that component related to gastric emptying.     

重症急性胰腺炎患者应用不同晶胶比液体早期复苏对预后的影响研究

目的探讨不同晶胶比液体早期复苏对重症急性胰腺炎（SAP）患者预后的影响。方法选择94例SAP患者,以入院24h内液体晶胶比1．5和3．0为界,将患者分成低晶胶比组（晶胶比〈1．5,26例）、中晶胶比组（晶胶比1．5～3．0,30例）和高晶胶比组（晶胶比〉3．0,38例）,观察入院后液体复苏成功患者24h机械通气率、氧合指数、腹腔内压（IAP）、第三间隙液体潴留量、液体复苏量参数及患者2周内生存率。结果高晶胶比组24h晶体液量、晶胶比、第三间隙液体潴留量及72h输液总量高于中、低晶胶比组[（3612±799）ml比（2309±417）、（2125±478）ml,（3．66±0．14）比（2．44±0．15）、（1．42±0．09）,（2835±632）ml比（1889±283）、（1866±305）ml,（11942±1162）ml比（9037±983）、（9401±1052）m1],差异有统计学意义（P〈0．05）;中晶胶比组24h晶胶比高于低晶胶比组,差异有统计学意义（P〈0．05）;低晶胶比组24h胶体液量高于高、中晶胶比组[（1507±335）ml比（994±234）、（949±141）m1],差异有统计学意义（P〈0．05）。中晶胶比组24h晶体液量、第三间隙液体潴留量及72h输液总量与低晶胶比组比较差异无统计学意义（P〉0．05）。高晶胶比组24h机械通气率、IAP明显高于中、低晶胶比组[65．8％（25／38）比23．3％（7／30）、26．9％（7／26）,（16．9±3．7）cmH2O（1emH20=0．098kPa）比（13．5±3．6）、（13．2±3．4）cmH2O],24h氧合指数明显低于中、低晶胶比组[（180．8±26．4）mmHg（1mmHg=0．133kPa）比（280．7±24．9）、（260．4±25．8）mmHg],差异均有统计学意义（P〈0．05）;高晶胶比组2周内生存率为34．2％（13／38）,低于中、低晶胶比组的86．7％（26／30）、57．7％（15／26）,与中晶胶比组比较差异有统计学意义（P〈0．05）,与低晶胶比组比较差异无统计学意义（P〉0．05）;低晶胶比组2周内生存率低于中晶胶比组,但差异无统计学意义（P〉0．05）。结论SAP患者早期宜采用适当晶胶比的控制性液体复苏,可减轻体液潴留和提高治愈率,且采用中晶胶比的控制性液体复苏策略效果最佳。     

Biotic and abiotic factors affecting Leptolegnia chapmanii infection in Aedes aegypti

The effects of water volume, container surface area and the density of hosts and fungal zoospores on the infectivity of the oomycete fungus Leptolegnia chapmanii to Aedes aegypti were investigated in the laboratory. Late 3rd or early 4th instars from a laboratory colony were used as hosts in all assays. Fourth instars infected with L. chapmanii for 48 h (6.1 +/- 0.2 x 10(4) zoospores/larva) were used as inoculum. Mortality rates were >90% in containers with 20 or fewer larvae when exposed to 1 infected larva, but they decreased to 37% in containers with 60 larvae. Mortality rates varied from 82% to 92% when healthy 4th instars were exposed to 1 and 2 infected larvae, respectively, whereas 100% mortality was obtained with > or =3 infected larvae. Infection and mortality rates in containers with volumes that varied from 300 to 5,000 ml but that had similar water surface area (397 cm2) varied from 89 to 92%, respectively. When water volume was held constant at 250 ml in containers with variable surface areas (14.5-875 cm(2)), larval mortality varied from 96% to 25%, respectively. The ability of L. chapmanii to infect mosquito larvae is dose dependent and influenced by larval density and surface area.     

Fluid and cation changes during head-out immersions in 25 degrees and 35 degrees C water

To compare fluid and ion changes during cold (25 degrees C) and thermoneutral head-out immersion (HOI) 9 men were studied under 4 resting conditions lasting 3 h: 2 in 35 degrees C and 2 in 25 degrees C water. At each temperature, subjects consumed 250 ml of either water or a 7% glucose polymer solution every hour to evaluate possible differences in fluid composition. Plasma volume increased by 3.9% for 35 degrees C and decreased by 9.7% for 25 degrees C HOI after 3 h. Urine flow increased significantly during HOI, but there were no differences between water temperatures (35 degrees C: 8.37 +/- 0.44; 25 degrees C: 9.55 +/- 0.57 ml.min-1). Free water clearance and urinary sodium excretion were also elevated during HOI, but water temperature did not alter the magnitude of the response. No HOI-induced kaliuresis was noted. Finally, there was a significant cold-induced increase in serum potassium and sodium, but this reflected largely the decrease in plasma volume. In sum, differences in water temperature seemed to have minimal influence on fluid and cation changes, an indication that immersion is the primary stimulus. Whether greater differences would be noted with colder water remains to be determined.     

培养环境对两性霉素B抑制白色念珠菌作用的影响

目的综合考察各种因素（不同的培养基、培养基的pH值、真菌接种浓度等）对两性霉素B（AmB）抑制白色念珠菌作用的影响,为临床合理用药提供理论依据。方法液体稀释法。结果在不同的培养基中,AmB对白色念珠菌的MIC值不同,随着pH值的增高及真菌接种菌液浓度增加,其MIC值增加。结论 AmB对白色念珠菌的MIC值会受到多种因素的影响,所以,进行药物的抗菌活性研究时应制定并严格执行统一的标准。     

Survival of human pathogenic bacteria in different types of natural mineral water

The aim of this study was to determine the survival of human pathogens (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) in five natural mineral waters (NMWs) with different properties and mineralization levels. Five NMWs from four Spanish spas with different dry residue at 110 °C were used: A = 76,935 mg/L; B = 1,827 mg/L; C = 808.4 mg/L; D = 283.8 mg/L; and E = 170.4 mg/L. An initial inoculum of 1 × 10(6) colony forming units (cfu)/mL was used for survival studies. Distilled water, chlorinated tap water and Mueller-Hinton broth were used as controls. Colony counts in all different waters were lower than those achieved with Mueller-Hinton broth over all incubation periods. A direct effect between the bacterial survival and the level of mineralization water was observed. The NMW E with low mineralization level along with the radioactive properties showed the highest antibacterial activity among all NMWs.     

Changes in limb volume during head-out water immersion in humans

In order to investigate the contribution of fluid shift from the legs to immersion-induced diuresis, 7 normal and 2 legless (both legs disarticulated at the hip) individuals were tested to measure changes in leg volume (normal subjects) and urinary excretion of solutes and water during a 3-h head-out water immersion (HOI) in thermoneutral water (34.5 +/- 0.5 degrees C) with a 1-h control period before and after immersion. On a separate day, a 5-h time control (TC) experiment on the same subjects was carried out by having them sit in thermoneutral air (29 +/- 0.1 degrees C, relative humidity 60%). The leg volume decreased by 192 +/- 20 ml during the 3-h HOI, which accounted for 3.5% of the average leg volume of the preimmersion period. During TC, however, the leg volume increased by 110 ml in the same time course. An increase in urine volume and sodium excretion was observed during HOI in both normal (P less than 0.05) and legless subjects. Net urine volume induced by HOI (urine volume during HOI minus urine volume during corresponding TC) in normal subjects was 494 +/- 89 ml in 3 h, which was close to a calculated volume reduction of the lower extremities during HOI (508 +/- 53 ml). The average net urine volume during HOI in the legless subject was 183 +/- 48 ml/min. The above results may suggest that the increase in renal water output is largely accounted for by a fluid shift from the lower extremities during HOI, however, the fluid other than that from the extremities should be accounted for as the urine source.(ABSTRACT TRUNCATED AT 250 WORDS)     

腹部手术后体液含量与分布的变化及其影响因素

目的 :观察腹部手术后体液含量与分布变化,探讨其变化规律和影响因素。方法 :选择2016年3至6月入住我科的61例病人,利用人体成分分析仪,检测病人术前1天和术后第1、3、5、7天细胞内液(ICW)、细胞外液(ECW)、总体液(TBW)的含量,并依据年龄、性别、手术种类、手术时间、液体净入量分组,分析影响病人体液变化的因素。结果 :与术前1天相比,术后第1天病人ICW、ECW、TBW明显增加(P0.05),且以ECW增加为主,并于术后第3至7天降至术前水平。不同种类手术病人术后第1天体液净增加量不同,女性较男性体液增加多,并且术后第1天体液净增加量与手术时间、液体净入量呈正相关。结论 :腹部手术后早期病人存在体液潴留现象,以ECW潴留为主;手术时间延长、液体净入量增加是术后病人体液潴留的主要影响因素。     

Streptokinase clot culture compared with whole blood culture for isolation of Salmonella typhi and S. paratyphi A from patients with enteric fever

The sensitivities of whole blood and clot cultures were compared in 155 patients with typhoid or paratyphoid fever. Salmonella typhi or S. paratyphi A were isolated from 98.7% of 5 ml 1:10 blood:broth ratio blood cultures and 94.8% of 5 ml streptokinase clot cultures (P greater than 0.05). There was no difference in the speed of isolation. Whole blood culture and clot culture were of nearly equal sensitivity in this group of patients.