Aggregatibacter aphrophilus pyogenic liver abscess in an immunocompetent young woman.

Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus/paraphrophilus) is a small Gram-negative coccobacillus with fastidious growth requirements. It is a normal commensal of the human oropharynx and upper respiratory tract, and it can infrequently cause invasive human diseases, including bone and joint infections and subacute infective endocarditis. Cases of liver abscess caused by Aggregatibacter aphrophilus have been sparsely recorded in the English-language literature, but have not yet been reported in Taiwan. Here we present a case of Aggregatibacter aphrophilus pyogenic liver abscess in an immunocompetent young woman. She recovered uneventfully after repeated percutaneous abscess aspiration and antibiotic treatment for 5 weeks.

Laboratory identification, risk factors, and clinical outcomes of patients with bacteremia due to Escherichia coli and Klebsiella pneumoniae producing extended-spectrum and AmpC type ß-lactamases.

BACKGROUND: Extended-spectrum ß-lactamase (ESBL)-producing bacteria coexpressing AmpC type ß-lactamase (ACBL) are associated with the laboratory issue of false susceptibility to third-generation cephalosporins. This study was to evaluate laboratory tests and clinical significance of bacteremic isolates of Escherichia coli and Klebsiella pneumoniae with both ESBL and ACBL [dual-type lactamases (DTL)]. METHODS: From 2006 to 2009, 78 E coli and 12 pneumoniae bacteremic isolates with reduced susceptibility to cefotaxime (CTX) or ceftazidime (CAZ) were identified and relevant patients' data were collected for analysis. Phenotypic and genotypic characterizations of these selected isolates were determined by inhibitor-based assays and polymerase chain reaction-based genetic analyses, respectively. RESULTS: Among the 90 isolates, 47 had DTL production. There was an increasing annual prevalence from 29% in 2006 to 56% in 2009 (p=0.02). Phenotypic assays had a sensitivity and specificity of 57% (43/76) and 93% (13/14) for ESBL detection and 95% (58/61) and 34% (10/29) for ACBL, respectively. Among the DTL-producing isolates, phenotypic assays yielded a higher false negative rate of ESBL detection than that of ACBL detection (70% versus 6%), while all false negative ESBL results were associated with ESBL genes other than bla(CTx-M). The majority of the DTL-producing isolates were in the category of resistance to CTX (47/47, 100%) and CAZ (44/47, 94%) by the Clinical and Laboratory Standards Institute (CLSI) 2010 interpretive criteria, of which many were considered intermediate or fully susceptible to CTX (25/47, 53%) and CAZ (15/47, 32%) by the previous ones (CLSI-2009). The DTL-producing isolates exhibited a lower susceptibility rate to fluoroquinolones, aztreonam, and ß-lactam/lactamase inhibitors than those with either ESBL or ACBL alone. The use of indwelling catheters or nasogastric tubes was associated with bacteremia due to the DTL isolates, but the mortality rates were not different among those due to isolates with ESBL, ACBL, or both. By multivariate analysis, Pittsburg bacteremia score and Charlson comorbidity index were the significant predictors for all-cause mortalities. CONCLUSION: Bacteremic episodes due to DTL-producing E coli and K pneumoniae became increasingly prevalent and were often associated with coresistance to antibiotics other than ß-lactams, but they were not associated with a worse prognosis than those due to ESBL- or ACBL-producing bacteria.

Serotypes, surface proteins, and clinical syndromes of invasive Group B streptococcal infections in northern Taiwan, 1998-2009.

BACKGROUND: The incidence of invasive Group B streptococcal (GBS) infections is increasing in the elderly and immunocompromised adults in many countries worldwide. There are, however, few reports regarding the current status of the infection in northern Taiwan. This study investigated retrospectively the molecular epidemiology and clinical syndromes of the invasive GBS diseases in a tertiary care hospital in northern Taiwan over the past decade. METHODS: One hundred twenty episodes of invasive GBS disease were recorded at Cathay General Hospital, a tertiary care, teaching hospital in northern Taiwan, from January 1998 to June 2009. Clinical information was acquired from medical records. Capsular serotypes and alpha family of surface proteins were genotyped with multiplex and specific polymerase chain reaction. RESULTS: Of all episodes, 58.3% was found in the elderly (age ≥ 65), 36.1% in nonpregnant women and young adults (age 18-64), and 5.9% in the neonates (0-90 days). Case-fatality rate was 6.7%. Eighty-three (69%) of the invasive isolates were available for genotyping. In sharp contrast to the studies in southern Taiwan (1991-2004), Type Ib (26.5%) was the most frequent invasive isolate, followed by V (22.9%), III (18.1%), VI (12%), Ia (10.8%), II (6%), VIII (2.4%), and nontypable strain (1.2%). In particular, Serotype VI, which had been rarely implicated in invasive infection, emerged as a significant pathogen. A significant trend of increase in incidence was observed for the infection (p<0.0001), with concurrent increase of cases in the elderly and of Serotype Ib and VI. There was significant association with young adults of Type II and III and chronic skin conditions and older adults with Type Ia and V and chronic cardiovascular diseases. Type V was closely associated with skin and soft tissue infection. Recurrent episodes (10%) occurred most often in patients with concomitant malignancy, with an average of 314 days for recurrence. CONCLUSIONS: The incidence of GBS invasive infection among nonpregnant women and adults is rising in northern Taiwan, particularly in the elderly caused by Serotype Ib and VI. Population-based surveillance program should be implanted for assessment of the disease burden to the susceptible adult population.