Antibiotic prophylaxis in “clean” surgical procedures

The incidence of infection for clean surgical procedures should be less than 2%. The majority of infections are exogenous from Staphylococcus aureus.These exogenous sources of bacteria include the ward, the theater environment, medical personnel, bed linen, and other infected patients. Endogenous infections may arise from the patient's own nose and skin; and although the majority of bacteria are staphylococcal, gram-negative intestinal bacteria may colonize the skin around the perineum and are, therefore, important pathogens in hip replacement and aortobifemoral grafts. Methods of reducing exogenous infection include theater discipline, ultra clean air, surgical scrub, and isolating infected patients on the ward. Endogenous infections may be minimized by avoiding prolonged preoperative hospital stay, careful shaving only around the incision, and skin preparation with iodophors or chlorhexidine in alcohol. There is no place for antibiotic prophylaxis in clean surgical operations, provided the patient has a normal defense mechanism and provided a foreign body is not being implanted into bone or the circulation. Because of the morbidity and potential mortality of infected implants, antibiotics should be used in clean prosthetic surgery.

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Résumé Le taux d'infection chirurgicale ne soit pas dépasser 2% lorsqu'il s'agit d'interventions dites aseptiques. La cause la plus fréquente en est lestaphylococcus aureus. Les sources exogènes de l'infection se situent au niveau des salles d'hospitalisation des annexes du bloc opératoire, du personnel médical, du linge et des malades déjà infectés. Les sources endogènes sont représentées par la peau et les orifices naturels du patient lui même. Bien que dans la majorité des cas le staphylocoque soit en cause des germes grams négatifs situés au niveau de la région périnéale peuvent être à l'origine de l'infection chirurgicale, en particulier lors des arthroplasties de la hanche et des greffes aortobifémorales.Pour réduire l'infection de cause exogène il convient d'observer une stricte discipline au niveau du bloc opératoire, de disposer d'air absolument pur, de respecter les règles d'asepsie avec rigueur et d'isoler tous les malades infectés. L'infection d'origine endogène peut être réduite en écourtant le séjour du malade à l'Hôpital avant l'intervention, en rasant soigneusement les téguments au niveau de la zone opératoire, en préparant la peau avec des solutions antiseptiques (solutés alcooliques d'iodophores ou de chlorexidine).Il est inutile de donner des antibiotiques à titre préventif dès lors que l'intervention à entreprendre est considérée comme aseptique, que le malade en bon état général possède un bon système de défense, et que l'opération ne consiste pas en la pose d'une prothèse au niveau de la coxofémorale ou d'un greffon aorto-bi-iliaque.

     

Multiple sample flow through immunomagnetic separator for concentrating pathogenic bacteria

The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels (<0.5 pathogenic bacteria/g) will not be consistently detected by this method. Here a multiple sample flow through immunomagnetic separator has been designed and tested to process large volume samples (50 to 250 ml). Preliminary results show >97% recovery of polydisperse magnetic particles (diameter range 1 to 8 microm) containing 29-33% w/w Fe3O4 content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 degrees C, is between 80 and 180 times higher than the standard 1 ml method.     

Periorbital swelling: the important distinction between allergy and infection

Orbital cellulitis and abscess formation are rare complications of sinusitis, however acute orbital inflammation is secondary to sinusitis in about 70% of cases. Delay in diagnosis must not occur to avoid serious complications such as blindness and life threatening intracranial sepsis. A case is reported in which despite late referral, emergency surgical intervention was sight saving.     

Analysis of the vitamin D receptor gene sequence variants in type 1 diabetes

Vitamin D is known to modulate the immune system, and its administration has been associated with reduced risk of type 1 diabetes. Vitamin D acts via its receptor (VDR). Four single nucleotide polymorphisms (SNPs) of the VDR gene have been commonly studied, and evidence of association with type 1 diabetes has been reported previously. We sequenced the VDR gene region and developed its SNP map. Here we analyzed association of the 98 VDR SNPs in up to 3,763 type 1 diabetic families. First, we genotyped all 98 SNPs in a minimum of 458 U.K. families with two affected offspring. We further tested eight SNPs, including four SNPs associated with P < 0.05 in the first set and the four commonly studied SNPs, in up to 3,305 additional families from the U.K., Finland, Norway, Romania, and U.S. We only found weak evidence of association (P = 0.02-0.05) of the rs4303288, rs12721366, and rs2544043 SNPs. We then tested these three SNPs in an independent set of 1,587 patients and 1,827 control subjects from the U.K. and found no evidence of association. Overall, our results indicate that common sequence variation in the VDR gene has no major effect in type 1 diabetes in the populations tested.     

Intra-articular hyaluronate in experimental rabbit osteoarthritis can prevent changes in cartilage proteoglycan content

OBJECTIVE: The purpose of this study was to determine the effects of intra-articular injections of high molecular weight (2000 kDa) sodium hyaluronate (HA) on the progression of articular cartilage degeneration in a rabbit partial medial meniscectomy model of osteoarthritis. DESIGN: Six experimental groups included normal, sham operated, and operated and injected animals, the latter injected once-weekly (for two weeks or twelve weeks, beginning four weeks after surgery) with either 1% (w/v) HA or phosphate buffered saline (PBS). Following assessment of gross morphology, serial adjacent blocks of full-depth articular cartilage were prepared from the tibial condyle for analysis of total water, hydroxyproline, DNA and proteoglycan (uronic acid) content, as well as the ratio of galactosamine to glucosamine. Samples were sub-divided into inner (medial) and outer (lateral) regions. RESULTS: No morphological differences were recognized between joints injected with PBS and those receiving HA. When analysed biochemically, there were no significant differences in hydration, hydroxyproline or DNA content between the experimental groups. In contrast, HA injection did affect changes in proteoglycan content. Expressed per tissue dry weight, uronic acid content in the operated group injected with PBS for two weeks was lower than normal (P<0.02), a result not seen in the corresponding HA injected group. After 12 weeks of PBS injections, uronic acid content (per dry weight) was higher than normal (P<0.01), an effect again not observed in the corresponding HA injected group. Results for the galactosamine: glucosamine ratio showed a reduction after 12 weeks of injections, but no differences between PBS and HA injected groups. CONCLUSIONS: Once-weekly, intra-articular injection of high molecular weight HA can prevent changes in proteoglycan content in tibial condylar articular cartilage, compared to PBS injected controls, in the rabbit partial meniscectomy model of osteoarthritis.     

Human campylobacteriosis in Scotland: seasonality, regional trends and bursts of infection

Fourier time-series models were constructed to study regional and national seasonality of human campylobacteriosis in Scotland between 1997 and 2001. Strong seasonality was demonstrated with an annual peak of reported cases in late June to early July. The prominence of this peak varied between regions, which was exemplified for the two major population centres: Lothian, with mixed urban/rural population, had a more prominent peak than Greater Glasgow, which has a predominantly urban population. No significant trend of annual cases of campylobacteriosis was found nationally and Fourier models successfully predicted the seasonal pattern of national and regional cases in 2002. During the period studied, the Fourier model identified >20 bursts of infection (potential outbreaks). Multi-regional bursts were also identified in the summers of 1998 and 2000 - the latter comprising the vast majority of the regions in Scotland, which could suggest a national outbreak.     

Usefulness of compensatory hyperkinesis in the noninfarcted left ventricular wall in separating single from multivessel coronary artery disease in patients with initial ST-elevation acute myocardial infarction

We assessed the contractility of the contralateral wall on 2-dimensional echocardiography in 50 patients with an initial ST-elevation acute myocardial infarction who underwent coronary angiography. Compensatory hyperkinesis, which we defined as a fractional thickening of >/=60% in the contralateral wall, was a strong predictor of single-vessel coronary artery disease, with a positive predictive value of 85%.