A cell-surface polysaccharide that facilitates rapid population migration by differentiated swarm cells of Proteus mirabilis

Swarming by Proteus mirabilis is characterized by cycles of rapid population migration across surfaces, following differentiation of typical vegetative rods into long, hyperflagellated, virulent swarm cells. A swarm-defective TnphoA insertion mutant was isolated that was not defective in cell motility, differentiation or control of the migration cycle, but was specifically impaired in the ability to undergo surface translocation as a multicellular mass. The mutation, previously shown to compromise urinary tract virulence, was located within a 1112 bp gene that restored normal swarming of the mutant when expressed in trans. The gene encoded a 40.6 kDa protein that is related to putative sugar transferases required for lipopolysaccharide (LPS) core modification in Shigella and Salmonella. The immediately distal open reading frame encoded a protein that is related to dehydrogenases involved in the synthesis of LPS O-side-chains, enterobacterial common antigen and extracellular polysaccharide (PS). Gel electrophoresis and electron microscopy showed that the mutant still made LPS but it had lost the ability to assemble a surface (capsular) PS, which gas-liquid chromatography and mass spectrometry indicated to be an acidic type II molecule rich in galacturonic acid and galactosamine. We suggest that this surface PS facilitates translocation of differentiated cell populations by reducing surface friction.

Role of amylase-treated, energy-dense liquid diet in the nutritional management of acute shigellosis in children: a controlled clinical trial

To evaluate if an energy-dense porridge liquefied by amylase-rich flour (ARF) from germinated wheat increased the calorie intake in children with acute shigellosis, we studied 66 children, aged 6-35 months, in a randomized, controlled clinical trial. Children were randomized to receive either an energy-dense porridge liquefied with ARF (group 1), a thick unaltered porridge (group 2) or a porridge diluted with water (group 3) to a similar viscosity as that in group 1. Mean +/- SD calorie intakes (kJ/kg/day) from the porridges were 280 +/- 113, 167 +/- 100 and 151 +/- 80 in groups 1, 2 and 3, respectively (p = 0.006, ANOVA). Total energy intakes (mean +/- SD) from the study diet and other food sources were 469 +/- 151, 377 +/- 121 and 351 +/- 100 kJ/kg/day, respectively (p = 0.006, ANOVA). Intake of breast milk was similar in all groups. Using multiple regression analysis the effect of ARF-treated energy-dense porridge in increasing the calorie intake persisted after adjusting for a number of confounders, such as age of the child, isolation of Shigella dysenteriae type 1 and fever. The results of this study suggest that ARF-treated porridge increases energy intake in infants and young children during acute shigellosis. This feeding approach may be useful in preventing malnutrition following dysentery due to shigellosis.

Conjunctival impression cytology fails to detect subclinical vitamin A deficiency in young children

Thirty-four asymptomatic children, ages 5-35 mo, were studied to compare the conjunctival impression cytology technique with the relative dose response test in detection of subclinical vitamin A deficiency. Conjunctival smears were collected from the infero-temporal-bulbar conjunctiva of each eye with a strip of cellulose acetate filter paper and transferred onto a glass slide. Venous blood was drawn at 0 and 5 h after administration of an oral dose of 1000 micrograms of retinol palmitate (relative dose response test). An increase in serum retinol concentration (> or = 20%) in the 5-h value was considered indicative of an inadequate liver store of vitamin A and hence subclinical vitamin A deficiency. Of the 34 children, 26 (76.5%) had moderate to severe protein-energy malnutrition. Only three children (9%) had abnormal conjunctival impression cytology, whereas 23 (68%) had abnormal relative dose response. Even more striking was the finding that only two of the 23 children with abnormal relative dose response had abnormal conjunctival impression cytology. The results suggest that the conjunctival impression cytology test has poor agreement with the relative dose response test results in assessing vitamin A status in young children. If relative dose response is considered an acceptable reference method for assessing vitamin A status, then the conjunctival impression cytology test cannot be considered a valid measure of subclinical vitamin A deficiency in this population.

Comparison of the modified relative dose response (MRDR) and the relative dose response (RDR) in the assessment of vitamin A status in malnourished children

The modified-relative-dose-response (MRDR) test and the relative-dose-response (RDR) test were compared in 49 mildly to moderately malnourished Bangladeshi children. The MRDR test had a significantly lower sensitivity, detecting only 71% of children with very low serum retinol (< or = 0.35 mumol/L) and 33% of children with low serum retinol (0.355-0.70 mumol/L) compared with 100% and 80% for the RDR test, respectively. The MRDR test showed a very strong dependency on retinol-binding protein (RBP) saturation (ie, percent saturation of RBP with retinol) compared with the RDR test. Only 3 (23%) of 13 children with RBP saturation > or = 55% but low vitamin A stores were diagnosed as abnormal by the MRDR test. This suggests that when apo-RBP concentration is limiting, as it is in malnourished children, didehydroretinol, the analog used in the MRDR test cannot effectively compete with retinol for binding to apo-RBP. Under these circumstances, the MRDR test is rendered ineffective. The possibility of increasing the sensitivity of the test by using a high dose of didehydroretinol needs to be investigated.

Administration of 25,000 IU vitamin A doses at routine immunisation in young infants

OBJECTIVE

To investigate whether monthly administration of vitamin A at routine immunisation produces any side-effects, and to examine the effect of this supplementation on the vitamin A nutrition status of infants.

DESIGN

A double-blind randomised placebo-controlled clinical trial.

SETTING

Immunisation clinic of a large diarrhoea treatment centre.

SUBJECTS

Infants aged 6-17 weeks who will receive their first diphtheria-pertussis-tetanus/oral polio vaccine (DPT/OPV) dose.

METHODS

Infants were randomly assigned to receive either 25,000 IU vitamin A or placebo. Three such doses were given with each immunisation dose at monthly intervals. Infants were examined by a physician before and during 24 h after the doses and any signs of toxicity were recorded. Venous blood was drawn at entry and 1 month after the 3rd dose for retinol assay.

RESULTS

One hundred and one infants received vitamin A and 98 received placebo. Decreased feeding, irritability, diarrhoea, and vomiting were comparable between the two groups. In the vitamin A group five infants developed bulging fontanelle; three of them developed it once (after 1st, 2nd and 3rd dose respectively), one developed it twice (after both the 2nd and 3rd dose), and the other infant after all three doses. In the placebo group a single child developed bulging fontanelle after the 3rd dose. In all the cases the bulging disappeared within 48 h of onset except in one infant, in whom it subsided at 60 h. The total bulging episodes in the vitamin A and placebo groups were 8 and 1 respectively (RR = 7.7; P < 0.04). However, none of these infants had irritability. At entry fasting retinol level was < 10 micrograms/dl in 35% infants and in 87% infants it was < 20 micrograms/dl. After the third dose fasting retinol level was marginally better in the vitamin A group (mean +/- s.d.: 21.9 +/- 8.2 vs 19.2 +/- 7.8; P = 0.05). However, 47% infants receiving supplementation still had serum retinol level <20 micrograms/dl.

CONCLUSION

The results suggest that administration of 25,000 IU of vitamin A in young infants along with routine immunisations, though associated with increased incidence of transient bulging fontanelle without any associated adverse signs or symptoms, may still be inadequate to prevent deficiency in this population.

SPONSORSHIP

This study was funded by the United States Agency for International Development (USAID) under grant no. DPE-5986-A-1009-00 with the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). The ICDDR,B is supported by countries and agencies which share its concern for the health problems of developing countries.

Identification and functional importance of plasma kallikrein in the synovial fluids of patients with rheumatoid, psoriatic, and osteoarthritis

OBJECTIVES

To determine and identify, unequivocally, if plasma kallikrein (PK) is present in the synovial fluid of patients with rheumatoid (RA), psoriatic (PA) and osteo (OA) arthritis, and to consider its functional importance in the inflamed joint.

METHODS

Therapeutically aspirated synovial fluids (pooled and individual samples, n = 66) were obtained from patients with arthritis. In addition, serum (n = 14) was collected from RA patients, and saliva (n = 10) and urine (n = 10) from normal individuals. Enzymic (amidase) and immunoreactive activities of PK and its precursor, prokallikrein (PPK), were determined. The presence of PK was assessed by incubation with soya bean trypsin inhibitor (SBTI), and by adsorption with anti-PK antibody linked to Sepharose. An enzyme-linked immunosorbant assay (ELISA) for PK was developed for quantitative measurement of total PK in biological fluids. Enhancement of the PK dose-response by RA synovial fluid made it necessary to remove RF from synovial fluids before determination of PK by ELISA.

RESULTS

Amidase activity was demonstrated in synovial fluid pools and shown to be inhibited completely by SBTI, and removed by prior treatment with anti-PK Sepharose. Total PK activity (PK + PPK) from individual synovial fluid specimens did not differ significantly between patients with RA (median activity 76 mU/g protein), PA (80 mU/g protein) or OA (60 mU/g protein). Similar results were obtained when active PK alone was measured. No correlation was found between active PK or total PK values and the severity score for individual joints. Most of the measured immunoreactivity was removed by adsorption with anti-PK antibody linked to Sepharose.

CONCLUSION

The results support the hypothesis that plasma kallikrein is present in synovial fluid. The enzyme may be important in the pathogenesis of inflamed joints.

Dietary energy intake, energy expenditure and activity pattern among selected rural and urban poor in Bangladesh

Rural-urban and seasonal differences in energy balance were studied among selected free living subjects, chosen from the poor population groups in Bangladesh. Individual dietary energy intakes were estimated by a combination of 24 hours recall and weighing method. Time allocation to various occupational and non-occupational activities were recorded by observation and questioning, and energy expenditures were calculated by using FAO/WHO/UNU guidelines. The male working adults in both the population groups studied were found to be in negative energy balance in both the seasons observed. In Jan-Feb when employment opportunities for the rural poor were few all age and sex groups were in negative energy balance, and when employment opportunities improved during May-June the situation reversed except for the male working adults. In urban areas, on the other hand, all age and sex groups, except the male working adults were in positive energy balance in both the seasons. Rural children under 10 years, had significantly higher energy expenditure (P < 0.023) than their urban counterparts. Seasonal difference in energy expenditure among the rural male adults is quite high. In the urban group there was no such seasonal difference. Apparently very high rural-urban difference in energy expenditure of the male adults (18-30 y) in season 1 may be attributed to very high energy demanding activities in which the observed subjects in rural areas were engaged during this season. Compared to their urban counterparts rural male adults (18-30 yrs.) were found to be devoted significantly higher time in occupational and heavy household activities.

Relationship between smoking and antioxidant nutrient status

The present study was designed to investigate the relationship between smoking and antioxidant nutrient intake and status. Smoker (n 44) and non-smoker (n 44) male students attending Dhaka University, aged between 22 and 28 years and living in a University Hall of Residence, were selected for the present study. Mean age, body weight, BMI and blood pressure were similar for both the smokers and non-smokers. Mean energy, protein and fat intakes were similar for both groups. Smokers had lower intakes of dietary vitamin C, carotenes and Zn but only the difference in Zn intake was statistically significant. There was no significant difference between smokers and non-smokers for either serum vitamin A (retinol) or vitamin E (alpha-tocopherol) level. The plasma vitamin C level of smokers was significantly lower than that of non-smokers (P = 0.0004). Smokers had significantly lower serum Cu (P = 0.04) and higher serum Zn levels (P = 0.003). Further, a significant dose-response relationship between smoking and vitamin C status was observed. Linear-regression analysis showed a significantly positive correlation between dietary intake and plasma vitamin C values in non-smokers (r 0.50; P = 0.0005). On the contrary, no such association was observed in smokers. These findings suggest that smoking may cause an imbalance in antioxidant nutrient intake and status.

Structural studies of the O-antigen oligosaccharides from two strains of Moraxella catarrhalis serotype C

The oligosaccharide parts from Moraxella (Branhamella) catarrhalis serotype C lipooligosaccharides were isolated by mild acid hydrolysis followed by gel permeation chromatography. Four different oligosaccharides could be identified from strain RS26 and two from strain RS10. The structures of the O-oligosaccharides were established by methylation analyses, mass spectrometry, and NMR spectroscopy. It is concluded that the oligosaccharide O-antigens from RS26 are a mixture of octa-, deca-, and undeca-saccharides, and most likely a heptasaccharide. Strain RS10 contains the deca- and the undeca-saccharide only. The structures for the oligosaccharides are shown below. [formula: see text] OS(7) [formula: see text] OS(8) [formula: see text] OS(10) [formula: see text] OS(11) Methylation analysis of the intact lipooligosaccharides showed that two Kdo residues were present, one terminal and one 4,5-substituted residue. It also showed that they consisted of a lipid A portion with 6-substituted glucosamine residues.

Structural studies of the Shigella boydii type 5 O-antigen polysaccharide

The structure of the Shigella boydii type 5 O-antigen polysaccharide has been investigated by sugar and methylation analyses, and specific degradations. It is proposed that it is composed of hexasaccharide repeating units with the following structure. The repeating unit also contains an O-acetyl group, linked to one of the primary positions. [formula: see text]

The effects of cigarette smoking on human gingival tissues (a histopathological study)

Gingival biopsy specimens were obtained from 9 smokers and 7 non-smokers during routine flap surgical procedure to investigate the effects of cigarette smoking on gingival epithelium and connective tissue. Although no remarkable histopathological difference was noted between gingival tissues of smokers and non-smokers, but smokers revealed relatively more epithelial keratosis, inflammatory cells, blood vessels and collagen fibres in connective tissue. Congestion of the capillaries were also more prominent in the smoker's gingival tissues.

Maternal and socioeconomic factors and the risk of severe malnutrition in a child: a case-control study

OBJECTIVE

To examine the relation of maternal and socioeconomic factors with the development of severe malnutrition in young children.

DESIGN

A case-control study.

SETTING

A large diarrhoea treatment centre in a metropolitan city.

SUBJECTS

Cases were 125 severely malnourished children, aged < 36 months, having weight-for-age < 55% of the United States National Center for Health Statistics (NCHS) median values. Controls (n = 125) were recruited concurrently matching for gender, disease type (i.e. diarrhoea or dysentery) and age stratum, having weight-for-age > 60% of NCHS median values.

INTERVENTION

Mothers of the children were interviewed to record personal history and various socioeconomic variables and examined for height and weight.

RESULTS

Maternal factors such as illiteracy, mothers' employment outside, lack of breastfeeding and maternal malnutrition (as indicated by low body mass index, weight or height); and selected socioeconomic indicators such as poor family income, use of unprotected surface water or unhygienic latrine were found to be significantly associated with severe malnutrition in their children. In multivariate analysis, maternal illiteracy and lack of breastfeeding were associated with approximately fourfold increased risk of severe malnutrition in their children. A strong positive association of employment of mothers outside homes with fivefold increased risk was surprising and may reflect a complex social problem of poor urban mothers; malnourished mothers were 2.5 times more likely to have severely malnourished children.

CONCLUSION

The findings confirm the well-known association of lack of maternal education and breastfeeding with severe malnutrition of their children. Maternal malnutrition may be a useful indicator to identify at-risk families with severely malnourished children. However, its causal association, though plausible, cannot be inferred from the study.

Structural studies of the O-polysaccharide from the lipopolysaccharide of Moraxella (Branhamella) catarrhalis serotype A (strain ATCC 25238)

The polysaccharide of the Moraxella (Branhamella) catarrhalis serotype A lipopolysaccharide was prepared by mild acid hydrolysis followed by gel permeation chromatography. The structure was established by methylation analysis, mass spectrometry, and NMR spectroscopy. It is concluded that the O-antigenic polysaccharide has the following structure. [formula see text] Methylation analysis of the intact lipopolysaccharide showed that the lipid A portion consisted of 6-substituted glucosamine residues. Methylation followed by methanolysis showed that two Kdo residues were present, one terminal and one 4,5-substituted residue. A terminal Kdo thus substitutes the branch-point Kdo in the 4-position.

Impact of health education on the feeding of green leafy vegetables at home to children of the urban poor mothers of Bangladesh

To evaluate the impact of health education on mothers, on the feeding of their children green leafy vegetables (GLV) at home, we studied 160 children aged 6 to 35 months and their mothers in two intervention groups and one comparison group. The mothers of the first intervention group (n = 44) were given health education including a feeding demonstration, by offering a single meal of cooked GLV to their children. The mothers in the second intervention group (n = 36) received health education only. Mothers of both the intervention groups were visited at home after eight weeks of intervention without prior notice, and for each of them an immediate neighbourhood mother having a child in the same age range was selected as a comparison mother (n = 80). During this visit, mothers were asked whether they had cooked GLV that day and fed these to their children; this was confirmed by spot-checking. Also, mothers were interviewed to elicit their perceptions about GLV. The percentages of mothers who thought that GLV are good for health were 88.7%, 86.1% and 76.2% in groups 1, 2 and comparison respectively (P = 0.06). However, the percentages of mothers who actually fed their children GLV were 57%, 64% and 26% in groups 1, 2 and comparison group respectively (P < 0.001). The influence of health education on GLV feeding persisted after controlling for the effect of maternal literacy (Mantel Haenszel chi-square = 16.99; P < 0.0001) and family income (Mantel Haenszel chi-square = 17.36; P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibitor regulation of tissue kallikrein activity in the synovial fluid of patients with rheumatoid arthritis

Tissue kallikrein (TK) and alpha 1-antitrypsin (AT)/TK complexes can be detected in SF from patients with RA if components of the fluids which interfere with the detection of TK are removed. alpha 2-Macroglobulin (alpha 2-M) in SF was demonstrated to contain trapped proteases which were still active in amidase assays. Removal of alpha 2-M from RA SF reduced their amidase activity. However, at least some of the remaining activity was due to TK because it was soya bean trypsin inhibitor resistant and trasylol sensitive and was partly removed by affinity chromatography on anti-TK sepharose. Removal of RF from the fluids reduced the values obtained for TK levels by ELISA. Addition of SF to human urinary kallikrein (HUK) considerably reduced the levels of TK detected suggesting the presence of a TK ELISA inhibitor in the fluids. Removal of components of > 300 kDa from SF markedly reduced the TK ELISA inhibitory activity and increased the values for both the TK and alpha 1-AT/TK levels in fluids as measured by ELISA. It is considered this novel inhibitor does not bind to the active site of TK but rather binds to the site reactive with anti-TK antibodies.

A new range of instruments ensuring easy and effective surgery for laparoscopic cholecystectomy

To work with ease and comfort in laparoscopic cholecystectomy, four instruments (Tohoku dissector, Tohoku forceps, short mantis device, and long mantis device) have been developed that can be used by any surgeon, even one not accustomed to this new procedure. These instruments have the advantage of offering a feel of open surgery and have been in use since February 1991 with significant comfort and safety.

Absorption of macronutrients from a high-protein diet in children during convalescence from shigellosis

Absorption of macronutrients and energy intake were determined in 29 children aged 24-59 months, during convalescence from acute shigellosis. A 72 h metabolic balance study was performed to determine the absorption of carbohydrate, fat, and protein. Eighteen children received a high-protein (5 g/kg/day) diet, and 11 children received a standard-protein (2.5 g/kg/day) diet. The mean +/- SD energy intake was 612 +/- 38 kJ/kg/day for children receiving the high-protein diet, compared with 633 +/- 50 kJ/kg/day for the standard-protein group. The coefficient of carbohydrate absorption was 89 and 92% for the high-protein and standard-protein diets, respectively (p = 0.059). The coefficient of protein absorption was 80 and 71% for the high-protein and standard-protein groups, respectively, and was significantly higher in the high-protein group (p < 0.01). Absorption of fat was similar in both groups. The results of the study show better absorption of protein from a high-protein diet during convalescence, which may have a positive impact on catch-up growth of children suffering from shigellosis.

Intake from an energy-dense porridge liquefied by amylase of germinated wheat: a controlled trial in severely malnourished children during convalescence from diarrhoea

OBJECTIVE

To evaluate the role of an energy-dense diet liquefied with amylase-rich flour from germinated wheat (ARF) in increasing the energy intake in severely malnourished infants and young children and its acceptability to mothers.

DESIGN

A randomized controlled clinical trial with two sets of controls.

SETTING

Nutrition rehabilitation unit of a large diarrhoea treatment centre where mothers stay with their very severely malnourished children.

SUBJECTS

78 severely malnourished children aged 5-18 months just recovered from diarrhoea.

INTERVENTION

Children were randomly assigned to receive either an energy-dense porridge made liquid by adding ARF (test diet) or an unaltered thick porridge of similar energy density (control 1 diet), or the porridge made liquid with addition of water to have the same viscosity as the test diet but of lower energy (control 2 diet), in four major meals a day for 5 days and intake was measured; breast-milk was measured by test weighing. Children also received an additional three milk-cereal meals a day.

RESULTS

The mean energy intake (95% CI, P value for difference between test and control) was 385 (339-431), 289 (251-327, P < 0.005), and 255 (222-289, P < 0.001) kJ/kg.d respectively. Feeding test diet was not associated with significant adverse effects e.g. on diarrhoea, vomiting, breast-milk intake, and was well accepted by mothers.

CONCLUSION

The results suggest that use of an energy-dense ARF-treated liquefied porridge increases calorie intake by very severely malnourished children during convalescence from diarrhoea, and that it does not produce any adverse effect.

Changes in body composition of malnourished children after dietary supplementation as measured by bioelectrical impedance

Body composition was measured with bioelectrical impedance in 35 malnourished children aged 24-59 mo to investigate the effect of a 3-wk feeding supplementation. Twenty children received a high-protein diet with 15% of total energy as protein, whereas 15 children received an isoenergetic standard-protein diet with 7.5% of energy as protein. Bioelectrical impedance analysis and anthropometry were done before and after 21 d of dietary supplementation. The children fed the high-protein diet gained significantly more body weight than those receiving the standard-protein diet (1.33 +/- 0.54 vs 0.88 +/- 0.47 kg, P < 0.02). The total body water and fat-free mass determined by bioelectrical impedance analysis showed that the group fed the high-protein diet increased significantly more (0.92 vs 0.58 kg) than those on the standard-protein diet (P < 0.02). Results of this study suggest that feeding a high-protein diet accelerates catch-up growth and restores the reference body composition in children recovering from malnutrition.

Clonal relationships among classical Vibrio cholerae O1 strains isolated between 1961 and 1992 in Bangladesh

In Bangladesh, the replacement of classical Vibrio cholerae by the E1 Tor biotype in 1968 and the reappearance of the classical biotype and its coexistence with the E1 Tor biotype after 1982 were never adequately explained. We have analyzed 23 classical V. cholerae isolates collected between 1961 and 1968, 14 classical isolates collected between 1982 and 1992 from the capital city, Dhaka, and 6 classical V. cholerae isolates collected from two southern districts of Bangladesh and studied restriction endonuclease cleavage patterns of rRNA genes (ribotypes) to investigate the clonal relationships among the isolates. Southern blots of total DNA digested with restriction enzyme BamHI, BglI, EcoRI, HindIII, or PstI were probed, using a cloned Escherichia coli rRNA operon. While restriction enzymes BamHI, EcoRI, and PstI failed to differentiate the isolates on the basis of ribotyping, BglI and HindIII produced digestion patterns that allowed differentiation. Ribotyping the isolates with BglI and HindIII revealed five different clones (ribotypes IA, IB, IIA, IC, and IIC) of classical vibrios in Bangladesh. Strains belonging to ribotypes IA and IB were isolated in Dhaka before 1968, and one ribotype (IA) was again isolated between 1982 and 1992. Ribotype IIA was isolated in 1988 and 1989, when both clones (IA and IIA) of classical vibrios coexisted with the EI Tor vibrios. Isolates belonging to ribotypes IC and IIC were collected in the southern districts of Bangladesh and were clearly different from those collected in Dhaka between 1968 and 1992 by ribotyping analysis with BglI. These results support the previous assumption that classical vibrios were never completely replaced in Bangladesh and also demonstrate the existence of more than one genetically different clone of classical V. cholerae.

Antibiotic resistance pattern of heat-labile enterotoxin (LT) producing Escherichia coli isolated from children with diarrhoea in Bangladesh: clonal relationships among isolates with different resistant phenotypes

Fifty-six heat-labile, enterotoxin-producing (LT+) Escherichia coli isolated from 33 children less than 5 years of age with diarrhoea were analysed for resistance to antibiotics, plasmid contents, and clonal relationships among isolates by ribosomal RNA (rRNA) fingerprinting (ribotyping). Fifty-five (98.2%) of the LT+ isolates were resistant either to tetracycline alone (48.2%) or to tetracycline and one or more other antibiotic, i.e. ampicillin, streptomycin, chloramphenicol, trimethoprim-sulfamethoxazole, or nalidixic acid. Most of the isolates harboured one or more plasmid but antibiotic resistance patterns did not always correlate with particular plasmid patterns. Ribotyping of the isolates using the restriction endonuclease EcoRI revealed a total of 7 different ribotypes, and ribotypes were shared by E. coli isolates with different antibiotic resistant phenotypes. The results indicate that in Bangladesh at least 7 different clones of LT+ E. coli acquired resistance to one or more different antibiotics in various combinations. However, a similar drug resistance pattern was not mediated by the same set of plasmids in all strains. The mechanism for the emergence and spread of antibiotic resistance among E. coli should be investigated further in Bangladesh, where LT+ E. coli is an important agent of early childhood diarrhoea.