Fluoroquinolone resistance in Haemophilus influenzae from nursing home residents in Taiwan: correlation of MICs and mutations in QRDRs.

AIMS: To study the association between number and positions of mutations with MICs of fluoroquinolone non-susceptible Haemophilus influenzae. METHODS AND RESULTS: More than 40% of 48 H. influenzae isolated from nursing home residents were not susceptible to fluoroquinolone. Amino acid changes in the quinolone resistance determining regions, and correlation with MICs and inhibition zone diameters were analysed. All isolates with reduced susceptibility to fluoroquinolones (MIC ≥0·125 µg ml-1 ) had at least one mutation in gyrA at position 84 and were resistant to nalidixic acid. Compared to isolates with reduced susceptibility, resistant isolates were associated with mutations in gyrA at positions 88 and 134, and in parC at position 88 (P < 0·001). Inhibition zone diameter for nalidixic acid disk ≥23 mm may detect susceptible isolates. CONCLUSIONS: Reduced susceptibility to fluoroquinolones was associated with mutations at position 84 in gyrA. A further increase in fluoroquinolone MIC was associated with mutations in gyrA at positions 88 and 134, and parC at position 88. SIGNIFICANCE AND IMPACT OF THE STUDY: Due to limited resistant H. influenzae strains, prior studies on association between positions of mutations and fluoroquinolone MICs were inconclusive. The comparison of mutations between isolates with susceptibility, reduced susceptibility and high resistance supported the importance of the present study.

Non-typhoidal Salmonella bacteraemia in elderly patients: an increased risk for endovascular infections, osteomyelitis and mortality.

Non-typhoidal Salmonella (NTS) is a common pathogen causing foodborne infections, bacteraemia, and extra-intestinal focal infections (EFIs) in humans. The study compares the clinical characteristics of elderly patients with NTS bacteraemia with those of young adults. Of 272 adults with NTS bacteraemia identified in this study, 162 (59·6%) were aged ⩾55 years. EFIs were observed in 36% of the 162 patients. The most common EFIs in the elderly patients (⩾55 years) was mycotic aneurysm, followed by pulmonary infections and bone/joint infections. Elderly patients more often had chronic heart, lung, renal and malignant diseases, had more EFIs, and a higher 30-day mortality rate. Independent factors of 30-day mortality in elderly patients were solid-organ tumour [adjusted odds ratio (aOR) 4·4, P=0·003], mycotic aneurysm (aOR 3·7, P=0·023) and shock (aOR 12·1, P<0·0001). HIV infection, autoimmune diseases, and receipt of immunosuppressive therapy were more often observed in young patients.

Epidemiology, disease spectrum and economic burden of non-typhoidal Salmonella infections in Taiwan, 2006-2008.

The purpose of this study was to understand the seasonal, geographical and clinical characteristics of Taiwanese patients hospitalized for non-typhoidal Salmonella (NTS) infections and their economic burden. Hospital data obtained from the Taiwan National Health Insurance (NHI) database between 2006 and 2008 were analysed. Infants had the highest annual incidence of 525 cases/100 000 person-years. Elderly patients aged >70 years had the highest in-hospital mortality rate (2·6%). Most (82·6%) gastroenteritis occurred in children aged <10 years. Septicaemia, pneumonia, arthritis and osteomyelitis occurred mainly in patients aged >50 years. A median medical cost for NTS-associated hospitalizations was higher for patients with septicaemia than for those with gastroenteritis. Seasonal variation of NTS-associated hospitalizations was correlated with temperature in different areas of Taiwan. In summary, infants had a high incidence of NTS-associated hospitalizations. However, the elderly had a higher in-hospital mortality rate and more invasive NTS infections than children.

Sporadic and outbreak cases of melioidosis in southern Taiwan: clinical features and antimicrobial susceptibility.

BACKGROUND: Melioidosis has been well known to be endemic in Thailand and Northern Australia, and was reported sporadically in Taiwan before 2005. METHODS: We retrospectively analyzed 58 patients with melioidosis in southern Taiwan from 2000 to 2005, including 40 clustered and 18 sporadic cases, for clinical characteristics and antimicrobial susceptibility. RESULTS: Fifty-one (88%) cases were found during the rainy season, and there was a significant correlation between the average monthly rainfalls and the case number (r = 0.37; p = 0.001). Diabetes mellitus was the most common underlying disease (35 cases, 60%). The majority (52 cases, 90%) had never traveled abroad before illness, indicating indigenous acquisition of Burkholderia pseudomallei. In comparison, clustered cases were older, less often had underlying diabetes mellitus and had a shorter duration of clinical symptoms before admission than sporadic cases. Acute form of melioidosis predominated, and shock at admission was independently associated with a grave prognosis. Overall, 22% of 58 patients died in hospitals. Ceftazidime, imipenem, meropenem, amoxicillin/clavulanic acid, co-trimoxazole, and doxycycline, as previously recommended, were the potentially therapeutic choices. The role of piperacillin/ tazobactam for melioidosis remains undefined. CONCLUSIONS: Melioidosis can occur sporadically or in a cluster in diabetic patients during rainy seasons in Taiwan.

Extraintestinal focal infections in adults with nontyphoid Salmonella bacteraemia: predisposing factors and clinical outcome.

BACKGROUND: Nontyphoid Salmonella (NTS) isolates lead to not only self-limited, acute gastrointestinal infections, but also bacteraemia with or without extraintestinal focal infections (EFIs). The risk factors associated with EFIs in adults with NTS bacteraemia were not clearly elucidated. METHODS: In a medical center in southern Taiwan, patients aged > or = 18 years with NTS bacteraemia between January 1999 and June 2005 were included for analysis. RESULTS: Of 129 patients, 51 (39.5%) were complicated with EFIs. The most common EFI was mycotic aneurysm, followed by pleuropulmonary infections and spinal osteomyelitis. Compared to patients with primary bacteraemia, those with EFIs had higher leucocyte counts (P = 0.004) and higher serum levels of C-reactive protein (P < 0.0001). The development of EFIs was associated with a higher mortality, more severe septic manifestations, longer hospital stays and duration of antimicrobial therapy. Univariate analysis revealed that diabetes mellitus (P = 0.02), hypertension (P = 0.02) and chronic lung disease (P = 0.006) were significantly associated with EFIs. However, patients with malignancy (P = 0.01) and immunosuppressive therapy (P = 0.03) were less likely to develop EFIs. On the basis of multivariate analysis, an independent factor for the occurrence of EFIs was age [adjusted odds ratio (aOR) 1.05; 95% confidence interval (CI) 1.02-1.07; P < 0.0001], whilst malignancy was negatively associated with EFIs (aOR 0.16; 95% CI 0.14-0.78; P = 0.01). CONCLUSION: Amongst patients with NTS bacteraemia, EFIs often occurred in the aged, and were associated with a higher mortality and morbidity. Recognition of specific host factors is essential for identification of EFIs which often demand early surgical interventions and prolonged antimicrobial therapy.