Search

Human infections caused by Weissella confusa are rarely reported. Ten patients with bacteraemia caused by W. confusa who were treated at a tertiary-care hospital in Taiwan during 1997–2007 were studied. All isolates were initially misidentified as various Lactobacillus and Leuconostoc species by two commercial automated identification methods, and were confirmed to be W. confusa by 16S rRNA sequencing analysis. MICs of these isolates for ten antimicrobial agents were determined by the agar dilution method. The characteristics of these patients included underlying malignancy (n = 4), presence of a central catheter (n = 6), surgery within the previous 3 months (n = 4) and concomitant polymicrobial bacteraemia (n = 5, 50%). Mortality was directly attributed to bacteraemia in two patients. All isolates exhibited high trimethoprim–sulphamethoxazole and ceftazidime MICs (≥128 mg/L) and were inhibited by linezolid, daptomycin, ceftobiprole and tigecycline at 4, 0.12, 2 and 0.12 mg/L, respectively. In conclusion, W. confusa should be included in the list of organisms causing bacteraemia in immunocompromised hosts. Novel antibiotics, including daptomycin, moxifloxacin, doripenem and tigecycline, exert good activity against W. confusa.

The inability of conventional identification systems to accurately identify Gordonia spp. often results in the misdiagnosis of infections by these rare pathogens, which require genomic sequencing for precise identification. In the present study, we describe nine cases of the various types of infection caused by Gordonia spp. From 1997 to 2008, 66 isolates (from 30 patients) initially identified as Rhodoccus spp. by conventional biochemical methods, by the Bacteriology Laboratory of National Taiwan University Hospital, were retrospectively analysed to assess the accuracy of species identification. Fifteen of these isolates (from nine patients) were later found to be Gordonia spp. by two molecular methods: PCR-restriction fragment length polymorphism for heat shock protein gene (hsp65) and the 16S rRNA gene sequencing analysis. Gordonia sputi (n = 8) was the most common species, followed by Gordonia terrae (n = 7). Most of the isolates were isolated from blood (n = 11), followed by soft tissue (n = 2) and eye (n = 2). Five patients presented with bacteraemia and two of these had catheter-related bloodstream infection. Two patients had soft tissue infections and another two patients had infective keratitis and conjunctivitis. The random amplified polymorphic DNA patterns for isolates from different patients were different, indicating that they were genetically unrelated. Accurate identification with molecular methods is required if the role of Gordonia spp. in causing infection is to be recognized.

Information on the relatedness of isolates causing repeated meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia is limited. An observational study of 177 patients with MRSA bacteraemia, admitted to the emergency department of National Taiwan University Hospital, was conducted from January 2001 to June 2006. Among these patients, 28 had a previous episode of MRSA bacteraemia and 59 died during the index episode of bacteraemia. Until December 2007, among the 118 patients who survived the index episode (101 without previous bacteraemia and 17 with previous bacteraemia), 24 (20.3%) had repeated MRSA bacteraemia. The duration from discontinuation of antimicrobial therapy to repeat episodes was in the range 35–854 days (median 86 days). Eight patients (33.3%) died as a result of the second bacteraemic episode. Clinical characteristics associated with repeated bacteraemia included the diagnosis of infective endocarditis and active malignancy. Pulsed-field gel electrophoresis and multilocus sequence typing analysis were performed for 32 pairs of available isolates recovered from patients with repeated bacteraemia and revealed that 29 of them (90.6%) were genetically closely-related strains. The majority of patients with repeated MRSA bacteraemia had recurrent infections and a high mortality rate.

Three consecutive workers from the same foundry had Mycobacterium massiliense keratitis. The strains isolated from each patient were identical. This is the first report of a non-surgery-related outbreak of non-tuberculous mycobacterial ocular infection. An investigation revealed that injured cornea with exposure to aerosolized non-tuberculous mycobacteria might account for this outbreak.

Genitourinary infections caused by nontuberculous mycobacteria (NTM) are rarely reported. The medical records of all patients with genitourinary NTM infections treated at National Taiwan University Hospital from 1996–2008 were retrospectively reviewed. Fifteen patients were identified, of whom 10 (67%) were male. More than two-thirds of patients had underlying conditions, the most common of which was chronic renal disease. Only one patient had AIDS. Acid-fast smears of urine were negative in all patients. Eleven isolates were available for further confirmation by sequencing of the 16S rRNA gene. Mycobacterium avium complex was the most common (n = 5, 33%), followed by both Mycobacterium abscessus (n = 2; 13%) and Mycobacterium fortuitum (n = 2; 13%). Of the 12 patients receiving anti-NTM treatment, only four received adequate prescribed regimens and none died of NTM infections. Two patients died of refractory urosepsis before the urinary NTM infections were diagnosed. The clinical characteristics of the 15 patients were also compared with 43 previously reported patients with genitourinary tuberculosis. Patients with genitourinary NTM infections were more likely to report constitutional symptoms, seek medical help within 1 month after the onset of symptoms and develop leukocytosis. Patients with genitourinary tuberculosis were more likely to have ureteral strictures and abnormal chest radiographs associated with active or inactive tuberculosis. Although rare, genitourinary NTM infections pose a significant threat to life and should be considered in the differential diagnosis of genitourinary infections, especially when patients are unresponsive to conventional antibiotic treatment.

We describe five patients with positive blood culture for Kocuria species. Three patients had catheter-related bacteraemia and one had infective endocarditis caused by Kocuria kristinae, and one had a K. marina isolate, which was considered to be a contaminant. Identification of the isolates was further confirmed by 16S rRNA gene sequence analysis. In conclusion, Kocuria species are an unusual cause of infection in immunocompromised patients. Accurate identification with molecular methods is imperative for the diagnosis of these unusual pathogens.