Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CNS). Its pathogenicity and virulence are more similar to Staphylococcus aureus than to a CNS. It causes severe infections with high mortality, such as endocarditis, but more often painful and prolonged skin- and soft-tissue infections. Little is known of its normal habitat. Whether it is an integral part of the normal skin flora like many other CNS has been questioned, since it is rarely seen in blood cultures. This study was designed to determine whether S. lugdunensis has a niche in the normal skin flora and to compare S. lugdunensis and S. aureus in these niches.From 75 healthy subjects in Kronoberg County, Sweden, 525 swabs were obtained from the nose, axilla, perineum, groin, breast, toe and nail bed of the first toe. Significantly more of the 525 skin samples as well as of the 75 healthy subjects yielded S. lugdunensis (50/75) as opposed to S. aureus.(16/75). Swabs from the nose frequently yielded S. aureus, but only rarely S. lugdunensis. Swabs from the groin and the lower extremities, especially the nail bed of the first toe, often yielded S. lugdunensis but rarely S. aureus. This study shows that S. lugdunensis is an integral part of the normal skin flora, primarily of the lower abdomen and extremities, and that the niches of this coagulase-negative staphylococcus are distinctly different from those of S. aureus. The predominant niches of S. lugdunensis explain why the bacterium is an uncommon contaminant of blood cultures.

Sore throat is common in primary healthcare. Aetiological studies have focused on the presence of a limited number of pathogens. The aim of the present study was to investigate the presence of a wide range of bacteria and viruses, including Fusobacterium necrophorum, in patients with pharyngotonsillitis and in asymptomatic controls. A prospective case control study was performed in primary healthcare in Kronoberg County, Sweden. Patients (n=220) aged 15 to 45 years with a suspected acute pharyngotonsillitis, and controls (n=128), were included. Nasopharyngeal and throat swabs were analysed for β-hemolytic streptococci, F. necrophorum, Mycoplasma pneumoniae, and Chlamydophila pneumoniae, and 13 respiratory viruses. Serum samples were analysed for antibodies to Epstein-Barr virus. The patient history and symptoms, including Centor score, were analysed in relation to pathogens. In 155/220 (70.5%) of the patients, as compared to 26/128 (20.3%) of the controls (p <0.001), at least one microorganism was found. Group A streptococci, F. necrophorum, and influenza B virus were the three most common findings, and all significantly more common in patients than in controls (p <0.001, p 0.001, and p 0.002, respectively). Patients with F. necrophorum only (n=14) displayed a lower Centor score than patients with Group A streptococcus only (n=46), but a higher score than patients with influenza B, other viruses, or no potential pathogen (Kruskal-Wallis p <0.001). A pathogen was detected in 70% of the patients, displaying a wide range of pathogens contributing to the aetiology of pharyngotonsillitis. This study supports F. necrophorum as one of the pathogens to be considered in the aetiology of pharyngotonsillitis.

Necrotizing pneumonia caused by Staphylococcus aureus carrying the gene for Panton-Valentine leukocidin is a newly described disease entity. We report 2 cases with intrafamilial spread.

BackgroundFusobacterium necrophorum is a well-known cause of Lemirre’s disease and accumulating evidence support its pathogenic role in peritonsillar abscess while its role in recurrent and chronic tonsillitis is uncertain. The objective of this study was to assess the prevalence of oropharyngeal colonisation with F. necrophorum and Beta-haemolytic streptococci in a cohort of patients scheduled for tonsillectomy due to recurrent or persistent throat pain, and to evaluate the dynamics of colonisation with repeated sampling during a follow-up time of 6 to 8 months.MethodsFifty-seven (57) patients aged 15–52 years scheduled for tonsillectomy due to chronic/recurrent tonsillitis or recurrent peritonsillar abscess were included. Throat swabs for the detection of F. necrophorum and Beta-haemolytic streptococci and clinical data was collected at inclusion, at the time of surgery and 6 to 8 months after surgery. Statistical analysis was performed using the Chi-square, Fisher’s exact and Mc Nemar tests.ResultsFusobacterium necrophorum was found in 28, 30 and 16 % of the patients at inclusion, surgery and follow up respectively. The corresponding results for beta-haemolytic streptococci were 5, 9 and 5 %. Patients colonised with F. necrophorum at follow-up, after tonsillectomy, were equally relieved from their previous throat pain as non-colonised patients. Looking at individual patients, the culture results for F. necrophorum varied over time, indicating a transient colonisation.ConclusionFusobacterium necrophorum was frequently found in throat cultures in this cohort of patients with recurrent or chronic throat pain leading to tonsillectomy. Colonisation was equally frequent in the asymptomatic cohort post-tonsillectomy, indicating that F. necrophorum is not alone causative of the symptoms. In an individual perspective, colonisation with F. necrophorum was transient over time.

ᰔStaphylococcus lugdunensis is a coagulase-negative staphylococcus with pathogenic properties similar to those of Staphylococcus aureus (4). Identification of S. lugdunensis is not necessarily straightforward, resulting in considerable variation in detection rates in different laboratories. Böcher and coworkers recently published data to increase awareness of this pathogen and described some basic criteria for identification to the species level (2). These criteria were (i) Eikenella corrodens-like odor, (ii) colony pleomorphism, (iii) prominent ␤-hemolysis after 2 days of incubation, and (iv) ID32Staph identification (bioMerieux). These criteria seemed, however, to be accurate only when the samples were cultured on Columbia sheep blood agar and not on agar containing 5% horse blood. They reported less-prominent odor and hemolysis on horse blood agar than on sheep blood agar. The identification problems led to differences in detection rates, and they reported an incidence (or in our view detection rate) of 53 infections per 100,000 inhabitants per year in a county in Denmark using Colombia sheep blood agar and zero to four S. lugdunensis infections per 100,000 habitants per year in neighboring counties using 5% horse blood.At the Department of Clinical Microbiology, Central Hospital, Växjö, Sweden, we have identified between 40 and 90 cases of S. lugdunensis per year over the last 10 years in our laboratory (Table 1). We have used Eikenella corrodens-like (bleach-like) odor, colony pleomorphism, and prominent ␤-hemolysis after 2 days of incubation combined with negative tube coagulase (with horse plasma; Statens Serum Institut, Copenhagen, Denmark), positive reactions with ornithine decarboxylase and pyrrolidonyl aminopeptidase (1, 3), and resistance to deferoxamine (250 g) (ROSCO; A/S Rosco, Taastrup, Denmark) (1) as standard criteria for identification of S. lugdunensis during this time. This simple strategy was validated by comparison to results obtained with API-Staph (bioMerieux) and Staph-Zym (Rosco) in 1996 (G.