Frequency of biocide resistance genes, antibiotic resistance and the effect of chlorhexidine exposure on clinical methicillin-resistant Staphylococcus aureus isolates.

OBJECTIVES: To detect genes conferring resistance to biguanides, quaternary ammonium compounds, beta-lactams and fluoroquinolones in clinical methicillin-resistant Staphylococcus aureus (MRSA) and to demonstrate whether reduced susceptibility is spread clonally and if the presence of any of the detected genes links to a specific epidemic MRSA. Finally, to identify if exposure to chlorhexidine may cause reduced susceptibility to antibiotics and chlorhexidine. METHODS: In total, 120 clinical MRSA isolates were isolated. qacA/B, qacG, qacH, norA, smr and blaZ genes were amplified by PCR. MICs of eight antibiotics were determined and PFGE was used for typing. Surface disinfection and residue tests were performed for chlorhexidine and a selection of isolates. RESULTS: qacA/B (8.3%), qacH (3.3%), norA (36.7%), smr (44.2%) and blaZ (97.5%) were prevalent within the population but qacG was not detected. EMRSA-15 (19.2%), EMRSA-16 (15%), P3 (15%) and H (12.5%) were the most common PFGE types. Clinical isolates demonstrated various degrees of susceptibility to chlorhexidine in the surface disinfection [mean microbiocidal effect (ME) = 0-1.91] and biocide residue (mean ME = 0.29-3.74) tests. Increases in post-exposure MICs were observed in both EMRSA-16 and the susceptible S. aureus control. CONCLUSIONS: In our study, isolates resembling PFGE type EMRSA-16 harboured more biocide resistance genes than other types. The observed reduction in susceptibility of clinical isolates to chlorhexidine may mean that a selective pressure is being exerted by residues in the clinical environment, and highlights the importance of efficacy testing on clinical strains and good infection control practices. The development of reduced microbial susceptibility to biocides represents a serious cause for concern in the clinical environment.

Delayed-interval delivery: extended series from a single maternal-fetal medicine practice.

OBJECTIVE: Our purpose was to review the extended experience of a single maternal-fetal medicine practice with delayed-interval delivery. STUDY DESIGN: We completed a retrospective review of our maternal-fetal medicine practice database from January 1991 through March 1999. Patients were derived from both primary and consultative practices. All patients were managed with tocolysis, antibiotics, and cerclage after delivery of the first fetus(es). Retained siblings were investigated by amniocentesis to exclude intra-amniotic infection. RESULTS: Twenty-four consecutive patients had attempted delayed-interval delivery. Exclusion criteria for delayed-interval delivery included monochorionicity, abruptio placentae, severe preeclampsia, and the need for hysterotomy. The mean latency interval was 36 days, with a range of 3 to 123 days. Additionally, patients with previous cerclage(s) had significantly shorter mean latency intervals than patients without previous cerclage(s). Patients with long latency intervals (> or =49 days) had earlier births of the first fetus. CONCLUSION: Selected multichorionic pregnancies may benefit from delayed-interval delivery. Patients with previous cervical cerclage(s) during the index pregnancy are less likely to achieve significant latency intervals. Even modest intervals between births of siblings at critical gestational ages can improve neonatal survival and decrease neonatal morbidity.

Delayed-interval delivery in multifetal pregnancy.

OBJECTIVE: Our goal was to review a single subspecialty practice experience with a uniform approach to delayed-interval delivery. STUDY DESIGN: A 66-month retrospective review of our maternal-fetal medicine practice database was completed. Fifty-nine sets of twins or triplets delivered at < 30 weeks' gestation were identified. No cases of twins or triplets who came to our care, either in consultation or as primary providers, were excluded. RESULTS: Forty-three patients were excluded as candidates for delayed-interval delivery because of monochorionicity, abruptio placentae, severe preeclampsia, and the need for hysterotomy. Sixteen pregnancies were identified as candidates for delayed-interval delivery, and we actually attempted to delay delivery in 9 of them. The details of the interval deliveries are summarized; there was a mean latency interval of 34 days with a range of 3 to 76 days. Pregnancies in which delayed-interval deliveries wer attempted were significantly less mature at the time of presentation than those managed by delivery of all infants initially. Perinatal mortality was significantly lower in the retained fetuses. CONCLUSIONS: This retrospective consecutive case review from a single maternal-fetal practice documents that selected multichorionic pregnancies may benefit from delayed-interval delivery. Modest intervals between siblings during critical gestational ages can improve newborn survival and decrease neonatal morbidity.

Epinephrine is unessential for stimulation of liver glycogenolysis during exercise.

To determine the role of adrenal medullary hormones in controlling the rate of liver glycogenolysis during exercise, adrenodemedullated (ADM) and sham-operated (SO) rats were run on a rodent treadmill at 21 m/min up a 15% grade for 0, 30, or 60 min. Rats were anesthetized by intravenous injection of pentobarbital sodium, and liver, muscle, and blood were collected and frozen. Liver glycogen decreased at similar rates in ADM and SO rats. Hepatic adenosine 3',5'-cyclic monophosphate (cAMP), plasma glucagon, and plasma free fatty acids increased to the same extent in both ADM and SO rats. The adrenodemedullation caused a reduction in glycogenolysis in the fast-twitch white region of the quadriceps, soleus, and lateral gastrocnemius during exercise. The normal exercise-induced increase in blood glucose and lactate and the decline in plasma insulin were not observed in the demedullated rats. During submaximal exercise the principal targets for epinephrine released from the adrenal medulla appear to be pancreatic beta-cells and skeletal muscle and not the liver.