Investigation of antibiotic and antibacterial agent cross-resistance in target bacteria from homes of antibacterial product users and nonusers.

AIM: To describe the relationship between antibiotic and antibacterial resistance in environmental and clinical bacteria from home environments across geographical locations, relative to the use or nonuse of antibacterial products, with a focus on target organisms recognized as potential human pathogens. METHODS AND RESULTS: In a randomized study, environmental and clinical samples were collected from the homes of antibacterial product users (n=30) and nonusers (n=30) for the isolation of target bacteria for antibiotic and antibacterial testing in three geographical areas (in USA and UK). Isolates were tested for antibiotic susceptibility, with selected antibiotic-resistant and antibiotic-susceptible isolates tested against four common antibacterial agents (triclosan, para-chloro-meta-xylenol, pine oil and quaternary ammonium compound). Prequalified users and nonusers at each location were randomly selected after meeting exclusionary criteria. Of 1238 isolates, more target bacteria were recovered from nonuser than user homes. Of Staphylococcus aureus isolates (n=33), none showed resistance to oxacillin or vancomycin; for Enterococcus sp. (n=149), none were resistant to ampicillin or vancomycin; and for Klebsiella pneumoniae (n=54)and Escherichia coli (n=24), none were resistant to third generation cephalosporins. Antibiotic resistance to one or more of the standard test panel drugs for Gram-positive and Gram-negative target bacteria was comparable between nonuser and user homes for both environmental and clinical isolates [e.g. resistance of environmental coagulase-negative (CN) Staphylococcus sp. was 73.8% (124/168) from nonuser homes and 73.0% (111/152) from user homes, and Enterobacteriaceae other than E. coli, 75.9% (186/245) from nonuser homes compared with 78.0% from user homes]. Of 524 Gram-negatives tested against preferred/alternative drugs, 97.1% (509/524) were susceptible to all antibiotics, across both groups. Isolates of S. aureus, Enterococcus sp. and CN Staphylococcus sp. susceptible to all preferred treatment drugs showed comparable antibacterial minimum inhibitory concentration (MIC) results between nonuser and user home isolates. For Gram-positives resistant to one or more preferred drugs, greatest resistance to antibacterial active ingredients was found in the nonuser group. For Gram-negatives, the antibacterial MIC data were comparable for isolates that were fully susceptible and resistant to one or more preferred/alternative treatment antibiotics. CONCLUSIONS: The results showed a lack of antibiotic and antibacterial agent cross-resistance in target bacteria from the homes of antibacterial product users and nonusers, as well as increased prevalence of potential pathogens in nonuser homes. SIGNIFICANCE AND IMPACT OF THE STUDY: It refutes widely publicized, yet unsupported, hypotheses that use of antibacterial products facilitates the development of antibiotic resistance in bacteria from the home environment.

The accuracy of conventional and three-dimensional thallium-technetium scans in patients with hyperparathyroidism resulting from multiglandular hyperplasia.

25 patients with hyperparathyroidism resulting from multiglandular hyperplasia were studied prior to cervical exploration. 43% of abnormal glands were correctly localized by preoperative thallium-technetium scintigraphy. In the 11 patients who underwent three-dimensional scanning, all glands already identified by scintigraphy were also localized in a third plane. In one patient an additional gland, not detected by the conventional scan, was visible.

Oral [111In]DTPA scintigraphic assessment of colonic transit in constipated subjects.

Patterns of colonic transit were assessed by a simple radioisotopic technique using 3.7 MBq of orally administered [111In]DTPA in 16 control subjects and 37 patients with intractable constipation. Normal subjects showed rapid diffuse spread of isotope through the colon resulting in low activity in all regions of interest (ROI). Activity was lost to feces at 24 hr and was virtually complete by 72 hr (median 94%, range 71-100%). Five constipated patients showed normal transit. Those with colonic inertia (N = 26) showed a significantly slowed geometric center of isotope compared to controls (P < 0.001), falling below the normal range at 48 hr. Percentage activity curves showed the major site of isotope hold-up to be in the transverse colon and splenic flexure. Other constipated patients (N = 6) showed late delay of the geometric center of isotope and accumulation of activity in the descending and rectosigmoid colon, compared to controls, at 96 hr. Oral [111In]DTPA colonic scintigraphy is a useful clinical test in the investigation of constipation.

Impact of conventional and three-dimensional thallium-technetium scans on surgery for primary hyperparathyroidism.

Twenty-nine patients with primary hyperparathyroidism underwent double-tracer subtraction scanning after injection of 201Tl as thallous chloride for thyroid and parathyroid images followed by 99mtechnetium as sodium pertechnetate for thyroid images prior to surgical exploration of the neck. The operative findings were correlated with the scans. All 23 adenomas (100%) and 13 of 18 (72%) hyperplastic glands were correctly localized. The ability of the scan to identify abnormal parathyroids was determined by the gland mass rather than whether the tissue was adenomatous or hyperplastic as all 32 (100%) abnormal glands weighing more than 180 mg were successfully localized in contrast to four of nine (44%) glands weighing less than 180 mg. An additional technique, in which emission tomography was carried out after subtraction scintigraphy, was used on 11 patients in the series. In all 11, the site of a single abnormal gland was predicted by the conventional subtraction scan: in nine of these patients, emission tomography provided additional localization of the gland in the anteroposterior plane.