Masako Kadowaki

Geographic distribution of fluoroquinolone-resistant Escherichia coli strains in Asia.

Fluoroquinolone (FQ) resistance is usually caused by point mutations within the quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC and/or parE. However, little is known about the worldwide increase in FQ-resistant Escherichia coli or, more specifically, about the geographical distribution of QRDR mutations and the clonal spread of isolates. In this study, we analysed 68 FQ-resistant E. coli isolates from eight Asian countries using QRDR amino acid mutation patterns and examined their susceptibility to FQs. Of the isolates, 38% had mutations at S83 and D87 of GyrA and S80 of ParC (MM/-/M-/-) and 34% had mutations at S83 and D87 of GyrA, S80 of ParC and S458 of ParE (MM/-/M-/M). MIC(50) values (minimum inhibitory concentrations for 50% of the isolates) for isolates with at least mutation at S458 of ParE for ciprofloxacin and prulifloxacin were relatively higher than MIC(50) values of isolates without this mutation. Based on their geographic distribution and the QRDR mutation patterns, the isolates were divided into a common type in which the organisms were isolated from three or more countries, and a local type in which the isolates were from one or two countries. Mutation types at S83L and D87N in GyrA and S80I in ParC with no or another site in the QRDR were the most frequent among the FQ-resistant isolates, especially among the common type. Gene typing indicated that isolates in the common type were not similar between countries. These data suggest that the increase in FQ-resistant E. coli strains is mainly generated by mutations in the QRDR in each geographical area rather than through intercontinental spread.

Combination therapy with micafungin and amphotericin B for invasive pulmonary aspergillosis in an immunocompromised mouse model

OBJECTIVES Antifungal monotherapy with polyenes, azoles or echinocandins is not always effective for invasive pulmonary aspergillosis (IPA). The main purpose of this study was to evaluate the efficacy of a combination of micafungin and amphotericin B for the primary treatment of IPA in an immunocompromised mouse model. METHODS Female ICR mice were used in all experiments. An immunosuppressive state was induced in mice by an intraperitoneal injection of cyclophosphamide. Mice were intratracheally inoculated with Aspergillus fumigatus conidia, treated with micafungin, amphotericin B or both for 7 days, and were tested for their survival 20 days after the Aspergillus inoculation. Fungal burden in lungs, serum galactomannan index (GMI) and histopathology of lungs, spleen and kidneys were also evaluated. RESULTS Combination therapy with micafungin and amphotericin B gave excellent survival of infected mice compared with monotherapy with micafungin or amphotericin B alone. Combined therapy reduced the fungal burden in the lungs and the serum GM levels compared with monotherapy or untreated controls, resulting in a significant histological improvement with disappearance of fungi in the lungs. CONCLUSIONS These findings suggest that combination therapy with micafungin and amphotericin B is more effective compared with monotherapy with either of them alone for IPA treatment.

Disseminated Cryptococcosis with Marked Eosinophilia in a Postpartum Woman

Disseminated cryptococcosis usually develops in immunosuppressed patients. A 33-year-old postpartum woman developed disseminated cryptococcosis with marked eosinophilia. She presented with a cough and a week-long fever. A computed tomography scan showed multiple pulmonary nodules randomly distributed. Eosinophils were observed to have increased in number in both her peripheral blood and bronchoalveolar lavage fluid. A transbronchial lung biopsy and cerebrospinal fluid specimens revealed findings consistent with cryptococcal infection. Disseminated cryptococcosis can present with marked eosinophilia of the peripheral blood and lung tissues. Additionally, the postpartum immune status may sometimes be involved in the development of opportunistic infections in previously healthy women.

P051: Factors responsible for methicillin-resistant Staphylococcus aureus outbreak in the neonatal intensive care unit

We observed a high incidence of methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in the neonatal intensive care unit (NICU) of Kyushu University Hospital in Japan from 2010 to 2012.