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A series of mec transformants of Staphylococcus aureus strain NCTC8325 were analysed for alterations in wall teichoic acid and lipoteichoic acid. Although the methicillin resistance determinant alters the autolytic behaviour of S. aureus, it had no effects on the cellular content, chain length, and alanine substitution of the lipoteichoic acid, or on the wall teichoic acid content and composition. However, independently of the presence or absence of the methicillin resistance determinant, level of methicillin resistance, or autolytic behaviour, a correlation was found between a 25% reduced cell wall phosphate content and either loss of prophages phi11 and 13 or a 30-kb deletion in the chomosmal SmaI-F fragment adjacent to the prophage φ11 attachment site.

A 5-month-old, 20 kg, intact female, German Shepherd Dog was presented to the Veterinary Hospital of the University of Zurich for evaluation of severe panting, exercise intolerance, and cyanosis. On clinical examination, the dog was thin but bright, alert, and responsive. A grade 5/6 systolic heart murmur was detected with the point of maximum intensity over the cranial left thorax. The peripheral pulse was weak, mu-cous membranes were pink, and capillary refill time was 2 seconds. Noninvasive blood pressure measurement was normal. Arterial oxygen saturation measured by pulse oximetry (SpO 2) on the tongue was 100% while in lateral recumbency and breathing room air. Based on these findings, congenital ventricular outflow tract obstruction was suspected and thoracic radiographs and echocardi-ography were performed. On radiography, moderate right-sided and mild left-sided cardiomegaly were present. The pulmonary vasculature was smaller than normal, with the exception of an enlarged and tortuous pulmonary artery and vein in the right cranial lung lobe. Moderate widening of the mediastinum was identified on the ventrodorsal projection (Fig 1). The abnormal vasculature in the right cranial lung lobe was considered compatible with an arterio-venous (AV) fistula. Widening of the cranial mediastinum was attributed to the presence of the thymus gland. Two-dimensional echocardiographic a findings included severe right ventricular hypertrophy with flattening of the septum and severe dilatation of the right atrium. Severe valvular pulmonic stenosis with a maximal systolic blood flow velocity (v max) of 5.0 m/s, a perimembranous ventric-ular septal defect with left-to-right shunting (v max 1.8 m/s), and mild subaortic stenosis (v max 2.4 m/s) were diagnosed by color Doppler and spectral Doppler examination, respectively. Considering the normal SpO 2 at rest, the shunting fraction through the AV fistula was judged to be clinically irrelevant. Adequate oxygen delivery at rest but cyanosis with slight effort was thought to be caused by right-to-left shunting through the AV fistula and ventric-ular septal defect associated with exercise-induced changes in pulmonary and systemic arterial pressures, possibly combined with peripheral cyanosis associated with decrease cardiac output caused by severe valvular pulmonic stenosis. During catheterization of the left jugular vein for ballooning of the pulmonic stenosis, the catheter could not be advanced into the right atrium, and entered the great cardiac vein instead. For better orientation, angiography of this aberrant vessel was performed and revealed a persistent left cranial vena cava (PLCVC) and dilated coronary sinus (Fig 2). Uneventful catheterization of the right heart through the right femoral vein followed by successful balloon valvuloplasty led to a reduction in pulmonic v max to 3.7 m/s. After the procedure, the owners reported normal respiratory rate, improved exercise tolerance, and no reccurrence of cyanosis. On a follow-up examination 3 years later, the owner consented t...

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