An evaluation of 2.0 McFarland Etest method for detection of heterogeneous vancomycin-intermediate Staphylococcus aureus

Background: Staphylococcus aureus with reduced susceptibility to vancomycin or heterogeneous vancomycinintermediate S. aureus (hVISA) have become increasingly reported from various parts of the world. hVISA cannot be detected by routine test for minimal inhibitory concentration (MIC) for vancomycin. The gold standard method for detection, population analysis profiles (PAP) method, is complicated, time-consuming, expensive, and needs well-trained microbiologists. Objective: Evaluate of 2.0 McFarland Etest method, in comparison with the PAP method, for detection of hVISA in clinical specimens. Methods: All methicillin-resistant S. aureus strains from clinical specimens isolated from consecutive patients attended at King Chulalongkorn Memorial Hospital and Siriraj Hospital, Bangkok between 2006 and 2007 were studied. 1 hundred nineteen specimens were obtained. The PAP method detected six hVISA strains 5 from blood and from cultures) from four patients at King Chulalongkorn Memorial Hospital, accounting for a prevalence of 6.35%. The MIC determined by agar dilution method was in the range of 2-3 μg/mL. Results: 2.0 McFarland Etest method detected no false positive and five false negatives (42%), and gave a sensitivity and a specificity of 16.7% and 100%, respectively. The one-point population analysis screening method detected two false positives and 1 false negative, and gave a sensitivity of 83.3% and a specificity and 98.2%. Conclusion: The 2.0 McFarland Etest method had a very good specificity but a poor sensitivity for detecting hVISA. It may be used as an alternative method to confirm detection of hVISA.

Presumably entomophthoramycosis in an HIV-infected patient: the first in Thailand.

The authors reported the case of a symptomatic HIV-infected woman with a slowly progressive infiltrative lesion which invaded in and around the nasal cavity over a 6-month period. Physical examination showed erythematous to violaceous plaques at the nasal and malar areas. Swelling of the inferior turbinate was noted in the right nare. Skin biopsy of the involved area revealed multiple nonseptate, broad, thin-walled hyphae within giant cells and granulomata. Entomophthoramycosis was diagnosed based on clinical features and histopathology. She was treated with intravenous amphotericin B for two weeks, followed by oral itraconazole 400 mg daily. At six months there was complete resolution of all lesions.

Invasive group A Streptococcal infections at Chulalongkorn University Hospital.

To determine whether the incidence and pattern of group A Streptococcal (GAS) infections in Thailand have paralleled those in the United States and Europe, we conducted a retrospective study of invasive GAS infections at Chulalongkorn University Hospital from 1995 to 1999. A total of 42 cases were identified. There were 18 males and 24 females (median age of 59 and 46 years, respectively). Most patients were in two age groups: 20-39 (33%) and 60-79 (38%). Underlying conditions were present in 34 patients (81%), including mostly chronic system diseases (50%), alcohol abuse (19%), diabetes mellitus (14%), connective tissue diseases (12%), immunosuppressive illnesses (12%), and human immunodeficiency virus infection (10%). The most common clinical presentations were skin and soft-tissue infections (31%), primary bacteremia (29%), and arthritis (14%). Of these, 24 (57%) presented with toxic shock syndrome (TSS). Overall mortality rate was 33 per cent. All GAS but one isolate were susceptible to penicillin.