HIV/HBV co-infection and rate of antiretroviral treatment change after highly active antiretroviral treatment initiation in a cohort of HIV-infected patients in Greece.

The current study investigated the impact of human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infection on the rate of change of antiretroviral drugs after the initiation of highly active antiretroviral treatment (HAART). The data on 1425 HIV-positive patients with recorded serology for hepatitis B surface antigen (HBsAg) were retrospectively analysed. The estimated rate of treatment change was slightly higher in the HBsAg-positive group (0.57 per year) compared with the HBsAg-negative group (0.50 per year). Although this difference was insignificant in multivariable modelling, the confidence intervals of the estimates barely included unity. Antiretroviral drug family, calendar period, prior exposure to antiretrovirals and the diagnosis of acquired immunodeficiency syndrome were independently associated with the number of drug alterations. A slight impact of co-infection on the frequency of treatment change after the beginning of HAART cannot be excluded. However, the paucity of studies on this issue necessitates the conduct of further research.

Seroepidemiology of human herpesvirus 8 (HHV-8) infection in injecting drug users.

A cross-sectional study was carried out in injecting drug users (IDUs) from Greece to assess the seroprevalence of human herpesvirus 8 (HHV-8) and to identify potentially associated risk factors. A total of 288 IDUs were tested for K8.1 antibodies to HHV-8 lytic antigen. Associations between HHV-8 serostatus and potential risk factors were examined using univariate and multivariate logistic regression analysis. Seroprevalence of HHV-8 was 24.3% (95% CI 19.5-29.7), increasing with age from 19.4% in those aged <30 years to 52.9% in those aged 40 years (P for trend=0.003). No statistically significant associations between HHV-8-positive status and gender, educational level, age at first drug injection, needle sharing, number of imprisonments, complications from drug overdose, HIV and HCV were observed. In the multivariate logistic regression analysis, older age (40 vs. <40 years, OR 3.30, 95% CI 1.14-9.56) and report of septicaemia/abscess (yes vs. no, OR 1.80, 95% CI 1.01-3.18) were each independently associated with higher HHV-8 seroprevalence. HHV-8 is highly prevalent in the IDU population in Greece. The independent association between HHV-8 and reported abscess or septicaemia supports the hypothesis that poor hygiene conditions in the setting of drug injection may contribute to HHV-8 transmission.

Different HLA-DR expression in endometriotic and adenomyotic lesions: correlation with transvaginal ultrasonography findings.

OBJECTIVE: Human leukocyte antigen-DR (HLA-DR) has been implicated in eutopic and ectopic glandular epithelial cells in endometriosis. We investigated the expression of HLA-DR in endometriotic and adenomyotic tissues within the stromal and glandular cells. Moreover, we correlate the HLA-DR expression according the transvaginal ultrasonography findings. METHODS: We studied operative and pathologic reports of 113 women who underwent laparoscopic or laparotomy treatment of endometrioma or adenomyosis. Tissues from 51 women with endometrioma and 62 women with adenomyosis were retrospectively evaluated. The distribution and intensity of the HLA-DR immunostaining was assessed using electron microscopy. Pathologic finding of the uterine junction zone and the size of endometrioma were evaluated with the laparoscopic results and the ultrasound findings. RESULTS: In adenomyosis tissues, the percentage of HLA-DR cells expression was significantly higher in stromal cells (83.9%) compared to glandular cells (25.8%), (p<0.001). The number of HLA-DR-positive endometriotic glandular cells was significantly higher than the total glandular adenomyotic cells (p<0.005). HLA-DR-positive cells was significantly different between stromal (p<0.016) and glandular cells (p<0.044) in each side of endometrioma. Finally, HLA-DR-positive percentage cells were significantly more frequent in the secretory phase than the proliferative in stromal and glandular cells in both groups. CONCLUSION: HLA-DR antigen expression in endometrium and adenomyotic tissues. However, HLA-DR expression is distributed preferentially in glandular epithelial cells in endometrioma and in the adenomyotic stroma. In both groups the HLA-DR expression was significantly higher in the secretory phase than the proliferative or glandular and stroma cells. Larger perspective studies are needed to establish the expression of HLA antigens in immune reactions which occur in adenomyosis and endometriosis.

Surgical-site infection surveillance in general surgery: a critical issue.

This prospective study assessed the Surgical Site Infection (SSI) rates in General Surgery and the microorganisms isolated. From January 2000 to October 2000, 898 patients were enrolled and electively operated in a General Surgery Clinic in Athens, Greece. Pre-coded questionnaires were used. The diagnosis and surveillance of SSIs was made by the surgeon-investigator who interviewed the patients. Patients were monitored during hospitalization and post-discharge for 30 days. Overall, 402 patients underwent a clean and 496 patients underwent a clean-contaminated operation. A total of 17 SSIs (4.2%) were observed in clean and 64 SSIs (12.9%) in clean-contaminated operations. Microorganisms were isolated in 36 of 65 (55%) of cases that microbiological evaluation was performed. Staphylococcus aureus was the commonest microorganism isolated, followed by Escherichia coli and Pseudomonas aeruginosa. SSI rates were higher than expected and most SSIs, 43 of 81 (53.1%), were diagnosed post-operatively. Post-discharge surveillance of SSIs remains a critical issue. Health care professionals, especially surgeons, should participate in surveillance networks and be aware of the results so to take appropriate action.

Adherence to guidelines for antibiotic prophylaxis in general surgery: a critical appraisal.

OBJECTIVES: To evaluate the adherence of general surgeons to guidelines for antimicrobial prophylaxis. This study was held from January 2000 until October 2000 in a General Surgery Clinic in a hospital in Athens, Greece. METHODS: Eight hundred and ninety-eight patients were enrolled and operated on electively. Questionnaires concerning demographic data, health status, type of surgery (clean and clean-contaminated) and parameters of antibiotic prophylaxis (antibiotic choice, route, dose, timing of first dose, timing of operative redosing and duration of prophylaxis) were completed. RESULTS: Of the patients, 44.8% underwent a clean surgical operation and 55.2% underwent a clean-contaminated surgical operation. Inguinal hernia repair and laparoscopic cholecystectomy were the commonest operations in each category. Second-generation cephalosporins were the most frequently prescribed antibiotics, in 67%. Although, only 78.5% of procedures required prophylaxis, it was administered in 97.5%, so it was not justified and inappropriately administered in 19%. It was revealed that 100% of patients received antibiotic prophylaxis on time. The choice of antimicrobial agent was appropriate in 70% and the duration of prophylaxis was optimal in 36.3%. The overall compliance rate of surgeons with guidelines for antibiotic prophylaxis was 36.3%. CONCLUSIONS: Adherence to separate aspects of guidelines for surgical prophylaxis has to be improved. The duration of antibiotic prophylaxis was the main parameter of interest. Interventions have to be made about the development, distribution and adoption of adequate guidelines in collaboration with surgeons.

Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women.

OBJECTIVE: The aim of this study was to examine the relationship of diet with serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 in women. DESIGN: Cross-sectional study. SETTING AND SUBJECTS: The population are 2109 women who were control subjects in a case-control study of breast cancer nested in the European Prospective Investigation into Cancer and Nutrition. Control subjects were randomly chosen among risk sets consisting of female cohort members alive and free of cancer (except non-melanoma skin cancer) at the time of diagnosis of the index case. Matching criteria were age at enrolment, follow-up time, time of the day of blood collection and study centre. Diet was measured through validated questionnaires. Serum hormone concentrations were measured by enzyme-linked immunosorbent assays. The relationship between serum IGF-I, IGFBP-3, and intake of nutrients and foods was explored by linear regression in models adjusted for energy intake, age, body mass index, smoking, physical activity, centre and laboratory batch. RESULTS: Serum IGF-I levels were positively related to protein intake (P(trend)<0.001), but not related to energy, fat or carbohydrate intake. Positive relationships were observed with the intake of milk (P(trend)=0.007), calcium (P(trend)<0.001), magnesium (P(trend)=0.003), phosphorus (P(trend)<0.001), potassium (P(trend)=0.002), vitamin B6 (P(trend)=0.03), vitamin B2 (P(trend)=0.001) and inverse relationships with vegetables (P(trend)=0.02) and beta-carotene (P(trend)=0.02). IGFBP-3 was not related with most of the nutrients and foods in this study. CONCLUSIONS: In this population, circulating IGF-I is modestly related with the intake of protein and minerals, and with milk and cheese, while IGFBP-3 does not appear to be related with diet.

Body mass index, waist circumference and waist-hip ratio and serum levels of IGF-I and IGFBP-3 in European women.

OBJECTIVE: To examine the relationship between body mass index (BMI) and waist-hip ratio (WHR) with serum levels of insulin-like growth factor-I (IGF-I), and its binding protein (IGFBP)-3. DESIGN: Cross-sectional study on 2139 women participating in a case-control study on breast cancer and endogenous hormones. Data on lifestyle and reproductive factors were collected by means of questionnaires. Body height, weight, waist and hip circumferences were measured. Serum levels of IGF-I and insulin-like binding protein (IGFBP)-3 were measured by enzyme-linked immunosorbent assays. Adjusted mean levels of IGF-I and IGFBP-3 across quintiles of BMI, waist circumference, and WHR were calculated by linear regression. Results were adjusted for potential confounders associated with IGF-I and IGFBP-3. RESULTS: Adjusted mean serum IGF-I values were lower in women with BMI<22.5 kg/m(2) or BMI>29.2 kg/m(2) compared to women with BMI within this range (P(heterogeneity)<0.0001, P(trend)=0.35). Insulin-like growth factor-I was not related to WHR after adjustment for BMI. IGF-binding protein-3 was linearly positively related to waist and WHR after mutual adjustment. The molar ratio IGF-I/IGFBP-3 had a non-linear relation with BMI and a linear inverse relationship with WHR (P (trend)=0.005). CONCLUSIONS: Our data confirm the nonlinear relationship of circulating IGF-I to total adiposity in women. Serum IGFBP-3 was positively related to central adiposity. These suggest that bioavailable IGF-I levels could be lower in obese compared to non-obese women and inversely related to central adiposity.

Postmenopausal serum androgens, oestrogens and breast cancer risk: the European prospective investigation into cancer and nutrition.

Considerable experimental and epidemiological evidence suggests that elevated endogenous sex steroids - notably androgens and oestrogens - promote breast tumour development. In spite of this evidence, postmenopausal androgen replacement therapy with dehydroepiandrosterone (DHEA) or testosterone has been advocated for the prevention of osteoporosis and improved sexual well-being. We have conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition. Levels of DHEA sulphate (DHEAS), (Delta4-androstenedione), testosterone, oestrone, oestradiol and sex-hormone binding globulin (SHBG) were measured in prediagnostic serum samples of 677 postmenopausal women who subsequently developed breast cancer and 1309 matched control subjects. Levels of free testosterone and free oestradiol were calculated from absolute concentrations of testosterone, oestradiol and SHBG. Logistic regression models were used to estimate relative risks of breast cancer by quintiles of hormone concentrations. For all sex steroids -the androgens as well as the oestrogens - elevated serum levels were positively associated with breast cancer risk, while SHBG levels were inversely related to risk. For the androgens, relative risk estimates (95% confidence intervals) between the top and bottom quintiles of the exposure distribution were: DHEAS 1.69 (1.23-2.33), androstenedione 1.94 (1.40-2.69), testosterone 1.85 (1.33-2.57) and free testosterone 2.50 (1.76-3.55). For the oestrogens, relative risk estimates were: oestrone 2.07 (1.42-3.02), oestradiol 2.28 (1.61-3.23) and free oestradiol (odds ratios 2.13 (1.52-2.98)). Adjustments for body mass index or other potential confounding factors did not substantially alter any of these relative risk estimates. Our results have shown that, among postmenopausal women, not only elevated serum oestrogens but also serum androgens are associated with increased breast cancer risk. Since DHEAS and androstenedione are largely of adrenal origin in postmenopausal women, our results indicated that elevated adrenal androgen synthesis is a risk factor for breast cancer. The results from this study caution against the use of DHEA(S), or other androgens, for postmenopausal androgen replacement therapy.

Meat consumption in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts: results from 24-hour dietary recalls.

OBJECTIVE: To evaluate meat intake patterns in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts. DESIGN AND SETTING: 24-Hour dietary recalls were assessed within the framework of a prospective cohort study in 27 centres across 10 European countries by means of standardised computer-assisted interviews. SUBJECTS: In total, 22 924 women and 13 031 men aged 35-74 years. RESULTS: Mean total meat intake was lowest in the 'health-conscious' cohort in the UK (15 and 21 g day-1 in women and men, respectively) and highest in the north of Spain, especially in San Sebastian (124 and 234 g day-1, respectively). In the southern Spanish centres and in Naples (Italy), meat consumption was distinctly lower than in the north of these countries. Central and northern European centres/countries showed rather similar meat consumption patterns, except for the British and French cohorts. Differences in the intake of meat sub-groups (e.g. red meat, processed meat) across EPIC were even higher than found for total meat intake. With a few exceptions, the Mediterranean EPIC centres revealed a higher proportion of beef/veal and poultry and less pork or processed meat than observed in central or northern European centres. The highest sausage consumption was observed for the German EPIC participants, followed by the Norwegians, Swedish, Danish and Dutch. CONCLUSIONS: The results demonstrate distinct differences in meat consumption patterns between EPIC centres across Europe. This is an important prerequisite for obtaining further insight into the relationship between meat intake and the development of chronic diseases.

Soy product consumption in 10 European countries: the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

OBJECTIVE: The aim of this study was to describe the variation of soy product intake in 10 European countries by using a standardised reference dietary method. A subsidiary aim was to characterise the pattern of soy consumption among a sub-group of participants with a habitual health-conscious lifestyle (HHL), i.e. non-meat eaters who are fish eaters, vegetarians and vegans. DESIGN: A 24-hour dietary recall interview (24-HDR) was conducted among a sample (5-12%) of all cohorts in the European Prospective Investigation into Cancer and Nutrition (EPIC). Study participants totalled 35 955 after exclusion of subjects younger than 35 or older than 74 years of age. Soy products were subdivided into seven sub-groups by similarity. Distribution of consumption and crude and adjusted means of intake were computed per soy product group across countries. Intake of soy products was also investigated among participants with an HHL. RESULTS: In total, 195 men and 486 women reported consuming soy products in the 24-HDR interview. Although soy product intake was generally low across all countries, the highest intake level was observed in the UK, due to over-sampling of a large number of participants with an HHL. The most frequently consumed soy foods were dairy substitutes in the UK and France and beans and sprouts among mid-European countries. For both genders, the sub-group of soy dairy substitutes was consumed in the highest quantities (1.2 g day-1 for men; 1.9 g day-1 for women). Participants with an HHL differed substantially from others with regard to demographic, anthropometric and nutritional factors. They consumed higher quantities of almost all soy product groups. CONCLUSIONS: Consumption of soy products is low in centres in Western Europe. Soy dairy substitutes are most frequently consumed. Participants with an HHL form a distinct sub-group with higher consumptions of fruit, vegetables, legumes, cereals and soy products compared with the other participants.

Diversity among high-level aminoglycoside-resistant enterococci.

A total of 55 Enterococcus faecalis and 21 Enterococcus faecium non-replicate isolates were obtained from routine clinical specimens, during a 1 year period, in a tertiary care hospital in Athens, Greece. The most common isolation site was the urinary tract (44% of E. faecalis and 33% of E. faecium isolates). No vancomycin resistance was detected. Ampicillin-resistant isolates did not produce beta-lactamase. High-level gentamicin resistance was detected in 22% and 0% of E. faecalis and E. faecium isolates, respectively. The corresponding figures for high-level streptomycin resistance were 40% and 33%. The aminoglycoside-modifying enzyme gene aac(6')+aph(2") was detected by PCR in 10 of 12 high-level gentamicin-resistant E. faecalis isolates, and the ant(6)-I gene in all high-level streptomycin-resistant isolates of both species. DNA fingerprinting by PFGE grouped 31 of 55 E. faecalis isolates into 10 clusters, and 10 of 21 E. faecium isolates into two clusters, containing two to seven isolates each. Two E. faecalis PFGE types, comprising isolates expressing high-level aminoglycoside resistance, and not observed among non-high-level aminoglycoside-resistant strains, were disseminated in building A of the hospital. In contrast, high-level aminoglycoside resistance seemed to have been acquired nosocomially by a number of genotypically different E. faecium types. Molecular typing was therefore instrumental in understanding the differences in the mode of spread and acquisition of high-level aminoglycoside resistance among these two different enterococcal species.

An electronic network for the surveillance of antimicrobial resistance in bacterial nosocomial isolates in Greece. The Greek Network for the Surveillance of Antimicrobial Resistance.

The present article reports an evaluation of the national electronic network for the continuous monitoring of antimicrobial resistance in Greece. The network employs a common electronic code and data format and uses WHONET software. Our four years' experience with the network confirms its practicality. A total of 22 hospitals in Greece are currently using the software, of which 19 participate in the network. Analysis of the information obtained has greatly helped in identifying the main factors responsible for the emergence of antimicrobial resistance in the participating hospitals. The data collected have also helped to identify priorities for further investigation of the genetic and molecular mechanisms responsible for the emergence of resistance and facilitated development of hospital-based empirical therapy of infections. In conclusion, the implementation of national networks for the surveillance of antimicrobial resistance should be regarded as a priority.

Bacterial resistance to ciprofloxacin in Greece: results from the National Electronic Surveillance System. Greek Network for the Surveillance of Antimicrobial Resistance.

According to 1997 susceptibility data from the National Electronic System for the Surveillance of Antimicrobial Resistance, Greece has high rates of ciprofloxacin resistance. For most species, the frequency of ciprofloxacin-resistant isolates (from highest to lowest, by patient setting) was as follows: intensive care unit > surgical > medical > outpatient. Most ciprofloxacin-resistant strains were multidrug resistant.

Molecular epidemiology of a hepatitis C virus outbreak in a haemodialysis unit. Multicentre Haemodialysis Cohort Study on Viral Hepatitis.

BACKGROUND: Haemodialysis patients are at high risk of infection by hepatitis C virus. The aim of this study was to investigate a hepatitis C virus outbreak which occurred in a haemodialysis unit, using epidemiological and molecular methods. METHODS: Five seroconversions to hepatitis C virus antibody (anti-HCV) were observed over a 6 month period and these were added to the four previously recorded anti-HCV-positive patients. All nine patients involved in the outbreak were tested for HCV RNA by reverse transcription-polymerase chain reaction and hepatitis C genotype determination was accomplished by a reverse hybridization assay. Furthermore, part of the NS5 region of hepatitis C genome (nucleotide positions 7904-8304) was amplified and sequenced in all HCV RNA-positive patients. Then, phylogenetic analysis of the nucleotide sequences obtained was carried out in order to investigate any possible epidemiological linkage among patients. Detailed epidemiological records were also available for all haemodialysis patients. RESULTS: Samples from all five incident cases and three out of four prevalent HCV infections were found positive for HCV RNA. HCV genotyping studies revealed that all incident cases were classified as 4c/d, whereas one and two prevalent cases were 1a and 4c/d respectively. Sequence comparisons and phylogenetic tree analysis revealed that six of the patients harboured very similar strains and clustered together, including all incident and one prevalent case, which was implicated as index case. Further epidemiological analysis was consistent with patient to patient transmission. CONCLUSIONS: Molecular and epidemiological analysis suggested that horizontal nosocomial patient to patient transmission was the most likely explanation for the virus spread within the haemodialysis unit under study.

High rates of antibiotic resistance among normal fecal flora Escherichia coli isolates in children from Greece.

OBJECTIVE: To study the distribution of antibiotic resistant Escherichia coli in the fecal flora of healthy children in Greece. METHODS: Rectal swabs were collected from 181 children, not suffering from infections and not undergoing antibiotic treatment, aged 6 months to 6 years, outpatients of a pediatric hospital, and plated on McConkey agar with ampicillin or trimethoprim. Isolated resistant colonies were identified to the species level and E. coli strains were studied further by molecular methods. RESULTS: Forty-four per cent of the children carried resistant E. coli, and in 20% resistance was transferable. Forty-seven per cent of the children with no history of antibiotic consumption during the last year were found to carry resistant strains in their feces, and transferable R plasmids were present in 23% of them. Forty per cent of the strains and 30% of the transconjugants were multiresistant. Although plasmids of various molecular weights and restriction endonuclease digest patterns were identified, six 60-MDa and four 80-MDa plasmids, originating from epidemiologically unrelated children, were found to be similar. CONCLUSION: Normal flora E. coli in Greece seems to constitute an important reservoir of resistance genes. Eradication of resistance from a population that comes into frequent contact with antibiotics seems to be difficult.

Electrical power lines and childhood leukemia: a study from Greece.

Residential proximity to electrical power lines of different voltage in relation to childhood leukemia was investigated through a case-control study undertaken in Greece during 1993-1994. The study comprised 117 incident cases of childhood leukemia and 202 age-, gender- and place-of-residence-matched controls. Four measures of exposure to magnetic fields were developed, using data provided by the Public Power Corporation of Greece: Voltage (V) divided by the distance (d), V/d2, V/d3 and an adaptation of the Wertheimer-Leeper code. Conditional-logistic-regression modeling was used to adjust for potential confounding influences of 18 variables. No significant trends of childhood leukemia risk with increasing exposure levels were noted, nor were there statistically significant elevations of disease risk at the higher exposure levels in each measure of exposure. These results do not support a causal link between residential proximity to electrical high-voltage wires and childhood leukemia risk, but in themselves do not refute a weak empirical association.

The risk profile of childhood leukaemia in Greece: a nationwide case-control study.

The risk profile of childhood leukaemia in Greece was studied through a case-control investigation that included all 153 incident cases of the disease, ascertained throughout the country during 1993 and 1994, and two hospital controls for every case matched for gender, age and place of residence. The data were analysed using conditional logistic regression and the associations are expressed in terms of adjusted odds ratios (OR) and their 95% confidence intervals. Cases were born to mothers of a higher standard education, the OR for an increment of four schooling years being 1.48 (1.17-1.87) and had higher birth weight, the OR for an increment of 500g being 1.36 (1.04-1.77). Pet ownership and birth after a pregnancy with anaemia were associated with increased risk, the ORs being 2.18 (1.14-4.16) and 2.60 (1.39-4.86) respectively. From the frequency analyses, indicative inverse associations were found with birth order, household crowding and previous hospitalization with allergic diseases, whereas indicative positive associations were found with diabetes mellitus during pregnancy and with neonatal jaundice. Substantial or significant elevations were not found with respect to maternal smoking and coffee drinking during pregnancy, diagnostic radiography and ultrasonographic examinations or blood transfusions. A significant inverse association with maternal consumption of alcohol could be due to multiple comparisons, but a detrimental effect can probably be excluded. A non-significant positive association with total shots of viral vaccinations and a weak non-significant inverse association with breast feeding were also found. We interpret the findings of this study as being compatible with acute childhood leukaemia being linked with delayed development of herd immunity to fairly common infectious agents, in conjunction with accelerated perinatal and early post-natal growth.

Life-style factors and medical conditions in relation to esophageal cancer by histologic type in a low-risk population.

A case-control study of esophageal cancer was conducted in Athens, Greece, during the 3-year period 1989-1991. Cases were 43 patients with incident esophageal squamous-cell carcinoma and 56 patients with incident esophageal adenocarcinoma hospitalized in any one of the 9 major hospitals in Athens, whereas controls were 200 injury patients admitted to the only Athens accident hospital. The data were analyzed by modeling through multiple logistic regression. Tobacco smoking and alcohol drinking were associated with both histologic types, but the odds ratios were generally lower than those observed in several other investigations. It may be that the high consumption of vegetables and fruits by the Greek population cushions the deleterious effect of tobacco, while the intake of ethanol in the form of wine during meals reduces the impact of this substance on the esophageal mucosa. A preference for very hot temperature for beverages and food was associated with significant elevation of the odds ratio to about 1.8 for esophageal cancer in general. There was non-significant evidence in our data to support earlier reports that aspirin intake may reduce the risk of cancer of the esophagus. Overall, we found no striking difference in the risk profile of the 2 histologic types of esophageal cancer.

Risk factors for nosocomial infections caused by gram-negative bacilli. The Hellenic Antibiotic Resistance Study Group.

Two hundred and ninety-nine Gram-negative hospital-acquired infections from 257 patients, consecutively identified during one month (November 1992) in five hospitals in the greater Athens area, were divided into four groups on the basis of the bacterium isolated: Group 1 (Escherichia coli group) included infections owing to E. coli, Group 2 (Proteus group) consisted of infections owing to Proteus spp. and Providencia spp., Group 3 (Kiebsiella/Enterobacter group) involved infections owing to Kiebsiella spp., Enterobacter spp., Citrobacter spp. and Serratia spp. Infections owing to Pseudomonas spp. and other non-fermenters were allocated into Group 4 (non-fermenters group). The four groups were studied in relation to risk factors including the duration of hospitalization, type of ward, underlying disease, history of operation, medical procedures/devices and antimicrobial therapy. A stepwise multiple logistic regression technique (SPSS Inc) was used to analyse the data, and the three groups (the Proteus group, the Klebsiella/Enterobacter group and the non-fermenters group) were analysed separately against the E. coli group. Infections with the Kiebsiella/Enterobacter group were associated with: (a) length of hospital stay before the infection, (b) treatment with newer antibiotics, and (c) hospitalization in an intensivecare unit (ICU). Infections with non-fermenters were associated with: (a) length of hospital stay before infection, (b) a urinary catheter, (c) type of disease (chronic infection being negatively associated), (d) treatment with newer antibiotics and (e) hospitalization in an ICU. Proteus group infections were associated with (a) length of hospital stay before infection, (b) treatment with newer antibiotics and (c) operation during present hospitalization (negative association). Interestingly, no specific hospitals were identified as risk factors. Identification of patients at risk for acquiring an infection owing to a nosocomial pathogen is vital in the development of a preventive strategy for hospital-acquired infections.