Prospective cohort study of enterotoxigenic Escherichia coli infections in Argentinean children.

In a follow-up study, enterotoxigenic Escherichia coli (ETEC) infections in 145 children from two communities located in northeastern Argentina were monitored for 2 years. The occurrence of diarrhea was monitored by weekly household visits. Of 730 fecal specimens collected, 137 (19%) corresponded to diarrheal episodes. ETEC was isolated from a significantly higher proportion of symptomatic (18.3%) than asymptomatic (13.3%) children (P = 0.04541). Individuals of up to 24 months of age were found to have a higher risk of developing ETEC diarrhea than older children (odds ratio [OR], 3.872; P = 0.00021). When the toxin profiles were considered, only heat stable enterotoxin (ST)-producing ETEC was directly associated with diarrhea (P = 0.00035). Fifty-five percent of the ETEC isolated from symptomatic children and 19% of the ETEC isolated from asymptomatic children expressed one of the colonization factors (CFs) investigated, i.e., CF antigen I (CFA/I), CFA/II, CFA/III, and CFA/IV; coli surface antigens CS7 and CS17; and putative CFs PCFO159, PCFO166, and PCFO20, indicating a clear association between diarrhea and ETEC strains that carry these factors (P = 0.0000034). The most frequently identified CFs were CFA/IV (16%), CFA/I (10%), and CS17 (9%). CFs were mostly associated with ETEC strains that produce ST and both heat-labile enterotoxin and ST. Logistic regression analysis, applied to remove confounding effects, revealed that the expression of CFs was associated with illness independently of the toxin type (OR, 4.81; P = 0.0003). When each CF was considered separately, CS17 was the only factor independently associated with illness (OR, 16.6; P = 0.0151). Most CFs (the exception was CFA/IV) fell within a limited array of serotypes, while the CF-negative isolates belonged to many different O:H types. These results demonstrate that some CFs are risk factors for the development of ETEC diarrhea.

[Comparison of the double burst stimulus with the train-of-four stimuli in monitoring muscle relaxation during anesthesia]. / Comparación del estímulo a doble ráfaga frente al tren de cuatro estímulos en la monitorización de la relajación muscular durante la anestesia.

OBJECTIVE: To compare double burst stimulus (DBS) and the train-of-four stimuli (TOF) for monitoring neuromuscular blockade during anesthesia in terms of muscle relaxation requirements, dose of anticholinesterase agents and the possibility of postanesthetic residual relaxation. PATIENTS AND METHODS: Patients were randomly assigned to two groups according to type of monitoring (DBS group, n = 29; and TOF group, n = 28), and were given an adjusted infusion of vecuronium to obtain response to stimulation with both methods of monitoring. When the block was considered to be sufficiently reversed in the operating theater, the patients were transferred to the postanesthesia recovery unit (PARU), where the coefficient between the fourth and first responses to TOF (T4/T1r) was obtained by electromyography and the patients were given the dose of neostigmine needed to obtain a T4/T1r > 70% RESULTS: Vecuronium was infused at a faster rate during anesthesia in the DBS group than in the TOF group (1.0 +/- 0.19 microgram.kg-1.min-1 and 0.8 +/- 0.24 microgram. kg-1.min-1, respectively, p = 0.005). T4/T1r was less than 70% upon arrival at the PARU in 10 DBS patients and in 2 TOF patients (p = 0.02). No differences were found in neostigmine doses given. CONCLUSIONS: The use of DBS increased the vecuronium dose required during anesthesia and risk in those patients who arrived at the PARU with residual muscle block (T4/T1r < 70%).

Colonization factors of enterotoxigenic Escherichia coli isolated from children with diarrhea in Argentina.

A prospective study was performed to evaluate the presence of colonization factor antigens (CFAs) in enterotoxigenic Escherichia coli (ETEC) strains isolated from 1,211 children with diarrhea in Argentina. One hundred nine ETEC strains that were isolated from seven different laboratories in various regions of the country were tested for CFAs by using monoclonal antibodies against CFA/I and E. coli surface antigens CS1, CS2, and CS3 of CFA/II and CS4 and CS5 of CFA/IV; a polyclonal antiserum against CS6 was used. The CFAs searched for were found in 52% of the ETEC strains: 23% of the strains carried CFA/I, 17% carried CFA/IV, and 12% carried CFA/II. All of the CFA/I strains produced heat-stable enterotoxin, and several of them were of the prevalent serotypes O153:H45 and O78:H12. Among the 19 strains expressing CFA/IV, 16 expressed CS5 and CS6 and produced the heat-stable enterotoxin and most were of serotype O128:H21; the remaining 3 strains produced CS6 only. No ETEC strains expressing CS4 were found. Most (11 of 13) of the CFA/II-carrying ETEC strains expressed CS1 and CS3, and 10 of them were of the O6:K15:H16 serotype and produced both heat-labile and heat-stable toxins. As many as 24 of the 109 CFA-negative ETEC strains gave mannose-resistant hemagglutination with erythrocytes from different species; 4 strains had high surface hydrophobicity, suggesting the presence of additional, as yet undefined, colonization factors in up to 25% of the ETEC isolates.