A review of risk factors for bovine tuberculosis infection in cattle in the UK and Ireland.

Bovine tuberculosis (bTB) is an important disease of cattle caused by infection with Mycobacterium bovis, a pathogen that may be extremely difficult to eradicate in the presence of a true wildlife reservoir. Our objective was to identify and review relevant literature and provide a succinct summary of current knowledge of risk factors for transmission of infection of cattle. Search strings were developed to identify publications from electronic databases to February 2015. Abstracts of 4255 papers identified were reviewed by three reviewers to determine whether the entire article was likely to contain relevant information. Risk factors could be broadly grouped as follows: animal (including nutrition and genetics), herd (including bTB and testing history), environment, wildlife and social factors. Many risk factors are inter-related and study designs often do not enable differentiation between cause and consequence of infection. Despite differences in study design and location, some risk factors are consistently identified, e.g. herd size, bTB history, presence of infected wildlife, whereas the evidence for others is less consistent and coherent, e.g. nutrition, local cattle movements. We have identified knowledge gaps where further research may result in an improved understanding of bTB transmission dynamics. The application of targeted, multifactorial disease control regimens that address a range of risk factors simultaneously is likely to be a key to effective, evidence-informed control strategies.

Preventing community-wide transmission of Cryptosporidium: a proactive public health response to a swimming pool-associated outbreak--Auglaize County, Ohio, USA.

The incidence of recreational water-associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues (e.g. pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g. childcare facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to pool A. Within 5 days of the first case being reported, pool A was hyperchlorinated to achieve 99·9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in pool A (matched odds ratio 121·7, 95% confidence interval 27·4-∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.

2013 multistate outbreaks of Cyclospora cayetanensis infections associated with fresh produce: focus on the Texas investigations.

The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0-∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.

Small-scale sheep and cattle enterprises in Scotland: Demographics, animal health, and biosecurity.

Livestock keepers who operate on a small scale in the United Kingdom are often described as either smallholders or hobby farmers; however, this is not always the case. There is another distinct population in Scotland. The crofting system promotes the preservation of a way of life that is significant to the cultural heritage of Scotland, whilst at the same time utilising and maintaining marginal land that could otherwise be deemed of very low productive value. We developed two cross-sectional questionnaire surveys to gather descriptive data about individuals from two populations (crofters and smallholders) who kept sheep and/or cattle. Our aim was to explore demographics, animal health, husbandry, and biosecurity practices of these two communities, including how they may interact with other livestock sectors. Most respondents in each population kept sheep, with far fewer keeping cattle. There was a distinct geographical difference in the approximate location of respondents' holdings. Movement of sheep was often local, temporary, and exempt from reporting to national databases. Visits from the vet were infrequent, but the vet remained an important source of animal health advice, alongside peer networks. The information from these surveys is valuable because policy decisions taken with predominantly larger, commercial-scale enterprises in mind also frequently apply to small-scale enterprises, even though these smaller enterprises may not have the same opportunity to influence those decisions or implement the requirements. Aspects of agricultural activity and food production at the scale explored in these surveys - including plurality of employment and diversification away from purely agricultural activities - are relevant to the United Nations Sustainable Development Goals of sustainable cities and communities, zero hunger and life on land. In this context, competent authorities should support this type of context-sensitive agriculture, alongside seeking to maintain animal health and welfare standards at the highest possible level on a national scale. Our surveys contribute to improved understanding of how these enterprises function and therefore will support policy makers when considering the breadth of keepers and circumstances affected by rules and regulations governing agriculture.

Bacteriological Survey of Fresh Minced Beef on Sale at Retail Outlets in Scotland in 2019: Three Foodborne Pathogens, Hygiene Process Indicators, and Phenotypic Antimicrobial Resistance.

ABSTRACT: The health and economic burden of foodborne illness is high, with approximately 2.4 million cases occurring annually in the United Kingdom. A survey to understand the baseline microbial quality and prevalence of food-related hazards of fresh beef mince on retail sale could inform risk assessment, management, and communication to ensure the safety of this commodity. In such a survey, a two-stage sampling design was used to reflect variations in population density and the market share of five categories of retail outlets in Scotland. From January to December 2019, 1,009 fresh minced beef samples were collected from 15 geographic areas. The microbial quality of each sample was assessed using aerobic colony count and Escherichia coli count. Samples were cultured for Campylobacter and Salmonella, and PCR was used to detect target genes (stx1 all variants, stx2 a to g, and rfbO157) for Shiga toxin-producing E. coli (STEC). The presence of viable E. coli O157 and STEC in samples with a positive PCR signal was confirmed via culture and isolation. Phenotypic antimicrobial sensitivity patterns of cultured pathogens and 100 E. coli isolates were determined, mostly via disk diffusion. The median aerobic colony count and E. coli counts were 6.4 × 105 (interquartile range, 6.9 × 104 to 9.6 × 106) and <10 CFU/g (interquartile range, <10 to 10) of minced beef, respectively. The prevalence was 0.1% (95% confidence interval [CI], 0 to 0.7%) for Campylobacter, 0.3% (95% CI, 0 to 1%) for Salmonella, 22% (95% CI, 20 to 25%) for PCR-positive STEC, and 4% (95% CI, 2 to 5%) for culture-positive STEC. The evidence for phenotypic antimicrobial resistance detected did not give cause for concern, mainly occurring in a few E. coli isolates as single nonsusceptibilities to first-line active substances. The low prevalence of pathogens and phenotypic antimicrobial resistance is encouraging, but ongoing consumer food safety education is necessary to mitigate the residual public health risk.

A new pathological system for grading DCIS with improved prediction of local recurrence: results from the UKCCCR/ANZ DCIS trial.

BACKGROUND: There is no consensus agreement regarding optimal management of locally excised ductal carcinoma in situ (DCIS) or features of greatest assistance in predicting disease behaviour. Cases in the UKCCCR/ANZ DCIS trial have been histologically reviewed to determine the features of prognostic importance. METHOD: A total of 72% of 1694 cases entered into the UKCCCR/ANZ DCIS trial had full pathological review. A large number of histological features were assessed, blinded to outcome and compared regarding ability to predict ipsilateral recurrence, as either DCIS or progression to invasive carcinoma. RESULTS: Pathological features associated with ipsilateral recurrence in univariate analysis included high cytonuclear grade, larger lesion size, growth pattern, presence of necrosis or chronic inflammation, incompleteness (or uncertainty of completeness) of excision and smaller margin width. Receipt of post-operative radiotherapy was also a strong prognostic factor.We report a novel sub-division of the large group of high-grade lesions, which enables identification of a very poor prognosis sub-group; namely, DCIS that is of high cytonuclear grade, predominantly (>50%) solid architecture, bearing extensive comedo-type necrosis (>50% of ducts). In addition, we found little difference in ipsilateral recurrence rates between low- and intermediate-grade groups. Hazard ratios for low, intermediate, high and the new, very high, grade were 0.42, 0.33, 0.62 and 1.00, respectively, for ipsilateral in situ or invasive recurrence. CONCLUSION: We present a novel pathological classification for DCIS with substantially better prognostic discrimination for ipsilateral recurrence than the classical categorisation based on cytonuclear grade alone.

Radiological and pathological size estimations of pure ductal carcinoma in situ of the breast, specimen handling and the influence on the success of breast conservation surgery: a review of 2564 cases from the Sloane Project.

BACKGROUND: The Sloane Project, an audit of UK screen-detected non-invasive carcinomas and atypical hyperplasias of the breast, has accrued over 5000 cases in 5 years; with paired radiological and pathological data for 2564 ductal carcinoma in situ (DCIS) cases at the point of this analysis. We have compared the radiological estimate of DCIS size with the pathological estimate of DCIS size. We have correlated these sizes with histological grade, specimen-handling methods, particularly the use of specimen slice radiographs, and the success or failure of breast-conserving surgery (BCS). METHODS: The Sloane Project database was interrogated to extract information on all patients diagnosed with DCIS with complete radiological and pathological data on the size of DCIS, nuclear grade, specimen handling (with particular reference to specimen radiographs) and whether primary BCS was successful or whether the patient required further conservation surgery or a mastectomy. RESULTS: Of 2564 patients in the study, 2013 (79%) had attempted BCS and 1430 (71%) had a successful single operation. Of the 583 BCS patients who required further surgery, 65% had successful conservation and 97% of them after a single further operation. In successful one-operation BCS patients, there was a close agreement between radiological and pathological DCIS size with radiology tending to marginally overestimate the disease extent. In multiple-operation BCS, radiology underestimated DCIS size in 59% of cases. The agreement between pathological and radiological size of DCIS was poor in mastectomies but was improved by specimen slice radiography, suggesting specimen-handling techniques as a cause. CONCLUSION: In 30% of patients undergoing BCS for DCIS, preoperative imaging underestimates the extent of disease resulting in a requirement for further surgery. This has implications for the further improvement of preoperative imaging and non-operative diagnosis of DCIS so that second operations are reduced to a minimum.

Lesion size is a major determinant of the mammographic features of ductal carcinoma in situ: findings from the Sloane project.

AIM: To assess the radiological features of calcific ductal carcinoma in situ (DCIS) in a large, multicentre dataset according to grade and size, and to investigate the possibility that DCIS has different mammographic features when small. MATERIALS AND METHODS: The dataset consisted of all Sloane Project DCIS cases where calcification was present mammographically and histological grade and size were available. The radiology data form classifies calcific DCIS as casting/linear, granular/irregular, or punctate. The pathology dataset includes cytonuclear grade and microscopic tumour size. Correlations were sought between the radiological findings and DCIS grade and size. The significance of differences was assessed using the chi-square test and chi-square test for trend. RESULTS: One thousand, seven hundred and eighty-three cases were included in the study. Of these, 1128, 485, and 170 had high, intermediate, and low-grade DCIS, respectively. Casting calcification was more frequently seen the higher the grade of DCIS, occurring in 58% of high grade, 38% of intermediate grade, and 26% of low-grade cases, respectively (p<0.001). Casting calcification was also increasingly common with increasing lesion size, irrespective of the histological grade (p<0.001). Thus casting calcifications in small (<10mm) high-grade DCIS lesions were seen with a similar frequency (50%) to those in moderate-sized (21-30 mm) intermediate-grade lesions (48%), and to those in large (>30 mm) low-grade lesions (46%). CONCLUSION: Lesion size has a strong influence on the radiological features of calcific DCIS; small, high-grade lesions often show no casting calcifications, whereas casting calcifications are seen in nearly half of large, low-grade lesions. As small clusters of punctate or granular calcifications may represent high-grade DCIS, an aggressive clinical approach to the diagnosis of such lesions is recommended as the adequate treatment of high-grade DCIS will prevent the occurrence of potentially life-threatening high-grade invasive disease.

Variations in the management of the axilla in screen-detected ductal carcinoma in situ: evidence from the UK NHS breast screening programme audit of screen detected DCIS.

The diagnosis and surgical management of screen-detected Ductal Carcinoma In Situ (DCIS) remains controversial including a range of axillary approaches and consequent morbidity. This study examined the management of the axilla in all patients with DCIS presenting through the United Kingdom National Health Service Breast Screening Programme (UK NHS BSP). Retrospective analysis of the UK NHS BSP identified 26,696 women initially diagnosed with DCIS over the 8 years 1 April 2003-31 March 2011. The final breast pathology of these women was upgraded to invasive ductal cancer in 5564 (20.8%) women or micro-invasive cancer in 1031 (3.9%) women. At first operation, 5290 (26.3%) of the 20,094 women who had a final post-operative diagnosis of DCIS only underwent axillary surgery (72.4% at the time of mastectomy, 23.8% breast conservation surgery, 3.8% axillary surgery alone). Performance of axillary surgery reflected increasing tumour size, micro-invasion or increasing nuclear grade for the final diagnosis of DCIS. More extensive nodal surgery was performed in those undergoing mastectomy; 10.8% of women had more than 8 nodes removed. Overall, 12.0% of women with invasive cancer, 1.7% with micro-invasion, and 0.2% with DCIS alone, were ultimately node positive. Improved pre-operative sampling of DCIS, axillary assessment by ultrasound with needle biopsy for suspected metastases, risk stratification for sentinel node biopsy (for high grade or extensive DCIS) and avoiding axillary clearance for a pre-operative diagnosis of DCIS alone should reduce unnecessary axillary surgery. Standards using such criteria for axillary surgery in screen-detected DCIS should be integrated into the NHS BSP.

Wilm's Tumor: An Update.

Major advances have been made against Wilms' tumor as a result of treatment methods developed by single institutions that then have been confirmed and extended by national cooperating groups. Better survival rates have been achieved, and therapy has been refined so that treatment can be reduced in early stage disease without jeopardizing tumor control. This results in fewer short- and long-term complications, an especially important consideration in children. Their organs and tissues are vulnerable to anti-mitotic treatments such as chemo- and radiotherapy, that can produce disabling if not lethal dysfunctions. This progress has been the result of the cooperative efforts by multiple specialists, and provides evidence of the value of such integrated studies. They have changed the outlook from a 90% death rate in the early years of this century to the 90% survival rate now possible with modern management.

Protein kinase C alpha expression in normal breast, ductal carcinoma in situ and invasive ductal carcinoma.

The purpose of this study was to determine if Protein Kinase C alpha (PKC alpha) is altered in expression or localisation in normal breast, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). We obtained 14 mixed cases of invasive ductal carcinoma (IDC) and DCIS, 36 pure DCIS cases and 25 cases of normal breast. The sections were stained immunohistochemically for PKC alpha expression. Staining was cytoplasmic. The results showed a progressive reduction in staining intensity from normal breast to invasive ductal carcinoma. The staining pattern was heterogeneous in the cytoplasm of DCIS and IDC, but homogeneous in the cytoplasm of normal breast ductal epithelium. Interestingly, mitotic cells and cells with aberrant nuclear morphology showed increased cytoplasmic staining in DCIS and IDC. PKC alpha activity is altered in dividing or abnormal cells, but overall expression is reduced in IDC. This raises the possibility of an alteration in the subcellular localisation of PKC alpha which may relate to changes in desmosomal adhesive state.

Positron emission mammography-guided breast biopsy.

UNLABELLED: Positron emission mammography (PEM) is a technique to obtain planar images of the breast for detection of potentially cancerous, radiotracer-avid tumors. To increase the diagnostic accuracy of this method, use of minimally invasive methods (e.g., core biopsy) may be desirable for obtaining tissue samples from lesions detected with PEM. The purpose of this study was to test the capabilities of a novel method for performing PEM-guided stereotactic breast biopsies. METHODS: The PEM system consisted of 2 square (10 x 10 cm) arrays of discrete scintillator crystals. The detectors were mounted on a stereotactic biopsy table. The stereotactic technique used 2 PEM images acquired at +/-15 degrees and a new trigonometric algorithm. The accuracy and precision of the guidance method was tested by placement of small point sources of (18)F at known locations within the field of view of the imager. The calculated positions of the sources were compared with the known locations. In addition, simulated stereotactic biopsies of a breast phantom consisting of a 10-mm-diameter gelatin sphere containing a concentration of (18)F-FDG consistent with that reported for breast cancer were performed. The simulated lesion was embedded in a 4-cm-thick slab of gelatin containing a commonly reported concentration of FDG, simulating a compressed breast (target-to-background ratio, approximately 8.5:1). An anthropomorphic torso phantom was used to simulate tracer uptake in the organs of a patient 1 h after a 370-MBq injection of FDG. Five trials of the biopsy procedure were performed to assess repeatability. Finally, a method for verifying needle positioning was tested. RESULTS: The positions of the point sources were successfully calculated to within 0.6 mm of their true positions with a mean error of +/-0.4 mm. The biopsy procedures, including the method for verification of needle position, were successful in all 5 trials in acquiring samples from the simulated lesions. CONCLUSION: The success of this new technique shows its potential for guiding the biopsy of breast lesions optimally detected with PEM.

Determination of tamoxifen and an hydroxylated metabolite in plasma from patients with advanced breast cancer using gas chromatography-mass spectrometry.

An assay has been established for the selective measurement of tamoxifen and its monohydroxy derivative, metabolite B, in human plasma. The assay was used to examine the concentrations of these compounds, relative to oestradiol-17 beta, in the plasma of patients undergoing tamoxifen therapy for advanced breast cancer. Oral administration of the drug (20 mg twice a day) raised the level of tamoxifen in plasma to approximately 200 ng/ml 20 days after the commencement of treatment. This level was 3000-fold higher than the corresponding concentration of oestradiol which remained within the range for post-menopausal women. Metabolite B was present in plasma at a much lower concentration than tamoxifen although in considerable excess over oestradiol. The overall results are discussed in relation to the possible mechanism of action of the drug.

Estrogen receptors and breast cancer.

Estrogen receptors have been assayed in a series of primary breast cancers from postmenopausal women; 59% of which were estrogen-receptor positive. These patients survived for a significantly longer period of time than those whose tumors were estrogen-receptor negative. The effect of estrogen-receptor status was only seen (and then markedly accentuated) in patients who had lymph-node invasion at the time of mastectomy. Such determinations also appear to be of value in preselecting those patients who, on recurrence, will benefit from tamoxifen therapy.

Comparative efficacy of positron emission tomography with fluorodeoxyglucose in evaluation of small (<1 cm), intermediate (1 to 3 cm), and large (>3 cm) lymph node lesions.

PURPOSE: Our objective was to determine if positron emission tomography (PET) with fluorodeoxyglucose (FDG; PET-FDG) imaging is equally efficacious in detection of metastases in small and large mediastinal lymph nodes as compared to CT scanning. MATERIALS AND METHODS: PET-FDG imaging, CT scanning, and histology results of sampled mediastinal lymph nodes were compared in 54 patients of total 118 patients studied. Efficacy of PET and CT was determined and compared in small (< 1 cm), intermediate (1 to 3 cm), and large (> 3 cm) mediastinal lesions. RESULTS: PET was accurate in 94% of patients in characterizing "N" disease as compared to 61% with CT. Overall, sensitivity, specificity, and accuracy of PET for staging mediastinal lymph nodes (n = 168 in 54 patients) was 96, 93, and 94%, as compared to 68, 65, and 66% with CT. Positive and negative predictive value of PET in detecting mediastinal adenopathy was 86% and 98%, as compared to 47% and 82% with CT, respectively. PET was also highly reliable and accurate for detecting lymph nodes < 1 cm, 1 to 3 cm, and > 3 cm in size with superior efficacy than CT. Sensitivity, specificity, and accuracy of PET for detecting malignancy in lymph node lesions < 1 cm in size was 97, 82, and 95%, respectively. CONCLUSION: PET-FDG imaging is equally reliable and accurate for detecting disease in small and large lymph node lesions in patients with suspected or proven lung cancer with better efficacy than CT.

Dynamic positron emission tomography with F-18 fluorodeoxyglucose imaging in differentiation of benign from malignant lung/mediastinal lesions.

PURPOSE: This study was done to evaluate the diagnostic utility of dynamic positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) imaging in patients with suspected malignant pulmonary lesions. We wanted to test the hypothesis that the rate of FDG uptake (FDG influx constant values) would differentiate malignant from benign lung or mediastinal lesions. MATERIALS AND METHODS: We performed segmental dynamic PET imaging studies following administration of FDG in 19 patients with indeterminate pulmonary lesions based on chest radiograph and/or CT scans. Patlak analysis was done to compute Ki (FDG influx constant) values and compared with FDG standardized uptake values (SUVs) and histology. RESULTS: FDG Ki values (mean+/-SD) were significantly greater (p < 0.01) in all 12 malignant lesions (0.029+/-0.02) as compared with 7 benign lesions (0.0024+/-0.0011) with good correlation to the SUV values. Distinct time activity curve patterns were identified in malignant and benign lesions with continued uptake in malignant lesions. CONCLUSION: Dynamic PET-FDG imaging accurately differentiates malignant from benign pulmonary lesions. In certain cases with equivocal findings on visual analysis and SUV values, dynamic imaging may be further helpful in differentiating benign and malignant lesions.

Mediastinal lymph node sampling following positron emission tomography with fluorodeoxyglucose imaging in lung cancer staging.

OBJECTIVES: To evaluate the predictive accuracy as well as the rates of false-positive and false-negative results of CT and positron emission tomography (PET)-fluorodeoxyglucose (FDG) imaging in detecting the metastatic intrathoracic lymph nodes in patients with suspected or proven non-small cell lung cancer (NSCLC). Our other objective was to determine the need for routine invasive sampling procedure in confirming PET/CT staging results. METHODS: The results of CT and PET-FDG scanning in 77 patients with suspected or proven NSCLC were correlated with the histologic findings of hilar/mediastinal lymph node sampling using mediastinoscopy, open biopsy, thoracotomy, or thoracotomy with resection. Patients were then classified into resectable and unresectable groups based initially on PET results and compared to histologic findings. RESULTS: The sensitivity, specificity, and accuracy of CT and PET for detecting metastatic lymphadenopathy were 68%, 61%, 63%, and 87%, 91%, and 82%, respectively. A change of management with routine sampling following PET was seen in five of six patients (83%) with false-positive findings (13%) but in none of four patients (9%) with false-negative findings. CONCLUSION: The false-positive findings of PET-FDG imaging affected selection of treatment in 83% of patients. However, false-negative results did not change management in any patient. This could potentially prevent unnecessary invasive thoracotomy, mediastinoscopy, or other sampling procedures in patients with negative PET results.

Report of a case of gross thymic hyperplasia in a child.

A large thoracic mass and a mediastinal lymph node were excised from an infant with a peripheral blood and bone marrow lymphocytosis. The 224-mass was composed of histologically normal thymus, and the lymph node architecture was partially effaced. Hypogammaglobulinemia was detected two years after thymectomy. The enormous thumus in this case fits the classic gross pathologic definition of hyperplasia. The possibility of associated thymic hyperfunction in this case is discussed.

Identification of the presence and type of biliary microflora by immediate gram stains.

Immediate gram stains were performed on gallbladder bile aspirated at the start of an operation for biliary disease in 191 consecutive patients undergoing elective biliary surgery. The results of the gram stains were telephoned to the operating theater within 20 minutes of collection. The over-all accuracy rate of the telephone gram stain reports compared with the subsequent bile cultures was 77 percent. The incidence of false-positive results was 12 percent, and false-negative results were recorded in 7 percent. The organism was identified wrongly by the gram stain in 4 percent of patients. These results have improved with experience and the over-all accuracy rate of gram stains on bile over the last 6 months have been 87 percent.

Selecting patients requiring antibiotics in biliary surgery by immediate gram stains of bile at operation.

The value of selecting patients for antibiotic cover during biliary surgery by the use of immediate gram stains of bile was determined in a nonrandomized prospective study which compared two groups of patients. Group A consisted of 119 consecutive patients in whom antibiotics were administered during operation according to the results of immediate gram stains on bile. Group B included 101 patients, none of whom received antibiotics. In Group A gentamicin was given for gram-negative bacteria, ampicillin for gram-positive organisms, and no antibiotics were given if no bacteria were seen on the gram stain. In Group A the incidence of wound sepsis was 7 percent, compared with 22 percent in Group B (p less than 0.005). Septicemia occured in 2 percent of Group A, compared with 8 percent in Group B. It is concluded that immediate gram stains of bile will provide a means of selecting patients requiring antibiotic cover during biliary surgery; furthermore, this procedure is a practical way of reducing postoperative sepsis while avoiding unnecessary antibiotic administration.