Olfactory and taste dysfunctions caused by COVID-19: a nationwide study.

BACKGROUND: Olfactory dysfunctions (OD) and taste dysfunctions (TD) are widely recognized as characteristic symptoms of COVID-19; however, the frequency and mode of occurrence has varied depending on the viral mutation. The prevalence and characteristics of OD/TD in Japan have not been definitively investigated. The purpose of this study is to assess the prevalence of OD/TD in Japan during the Alpha variant epidemic, and measure symptom prolongation at 6 months and 1 year later following initial infection. METHODS: Patients treated for COVID-19 between February to May 2021 were evaluated for OD/TD symptoms and provided with a QOL questionnaire. Olfactory tests and taste tests were performed using Open Essence and Taste Strips, respectively. RESULTS: Among the 251 COVID-19 patients who participated, 119 underwent both olfactory and taste tests. Prevalence of subjective OD and TD at the time of survey was 57.8% and 40.2%, respectively. After 12 months, the prevalence fell to 5.8% for OD and 3.5% for TD. Among the OD/TD patients, 36.6% experienced parosmia, and 55.4% experienced parageusia. Prevalence of parosmia and parageusia was higher at 6 and 12 months than at the time of survey. Patients with long-lasting disease reported qualitative dysfunctions and scored significantly higher in food-related QOL problems. Most patients who were aware of their hyposmia had low scores on the olfactory test (83.1%). In contrast, only 26.7% of patients who were aware of their hypogeusia had low scores on the taste test. CONCLUSIONS: The prevalence of COVID-19-related OD and TD at the time of survey was 57.8% and 40.2%, respectively. Subjective symptoms of OD and TD persisted for one year in 5.8% and 3.5% of patients, respectively. More than half of the patients with OD or TD complained of qualitative dysfunction and a decrease in their QOL related to eating and drinking. Most patients with TD did not have true TD, but rather developed flavour disorders associated with OD. This conclusion is supported by the finding that patients with subjective OD had low scores on the olfactory test, whereas most patients with subjective TD had normal scores on the taste test.

Regional air quality in Leipzig, Germany: detailed source apportionment of size-resolved aerosol particles and comparison with the year 2000.

A detailed source apportionment of size-resolved aerosol particles in the area of Leipzig, Germany, was performed. Sampling took place at four sites (traffic, traffic/residential, urban background, regional background) in parallel during summer 2013 and the winters 2013/14/15. Twenty-one samples were taken per season with a 5-stage Berner impactor and analysed for particulate mass, inorganic ions, organic and elemental carbon, water-soluble organic carbon, trace metals, and a wide range of organic species. The compositional data were used to estimate source contributions to particulate matter (PM) in quasi-ultrafine (up to 140 nm), accumulation mode, and coarse size ranges using Positive Matrix Factorisation (PMF) receptor modelling. Traffic (exhaust and general traffic emissions), coal combustion, biomass combustion, photochemistry, general secondary formation, cooking, fungal spores, urban dust, fresh sea/road salt, and aged sea salt were all found to contribute to different extents to observed PM concentrations. PMF derived estimates agreed reasonably with estimates from established macrotracer approaches. Quasi-ultrafine PM originated mainly from traffic (20-50%) and photochemistry (30-50%) in summer, while it was dominated by solid fuel (mainly biomass) combustion in winter (50-70%). Tentatively identified cooking aerosol contributed up to 36% on average at the residential site. For accumulation mode particles, two secondary sources typically contributed 40-90% to particle mass. In winter, biomass and coal combustion contributions were up to ca. 25% and 45%, respectively. Main sources of coarse particles were diverse and included nearly all PMF-resolved ones depending on season and air mass origin. For PM10, traffic (typically 20-40% at kerbside sites), secondary formation (30-60%), biomass combustion (10-15% in winter), and coal combustion (30-40% in winter with eastern air mass inflow) were the main quantified sources. At the residential site, contributions from biomass combustion derived up to 60% from local emissions. Coal combustion as a significant source was only present during eastern air mass inflow and showed very similar concentrations at all sites, indicating the importance of trans-boundary air pollution transport in the study area. Overall, nearly half of the PM10 mass was attributed to urban sources by a simple subtractive approach with highest reduction potentials of up to 80% for local (urban) mitigation measures in ultrafine and coarse particles. Local increments of elemental carbon have decreased by about 50% as compared to the year 2000, corroborating results from a former study on the positive effects of a low emission zone, implemented in Leipzig in 2011.

Applying a PCR-based open-reading frame typing method for easy genotyping and molecular epidemiological analysis of Pseudomonas aeruginosa.

AIMS: Molecular epidemiological techniques, such as pulsed-field gel electrophoresis (PFGE), or multilocus sequence typing (MLST) have facilitated our understanding of the transmission routes of nosocomial infections by Pseudomonas aeruginosa. However, they are time consuming and technically demanding. To perform molecular epidemiological analysis in a standard microbiology laboratory, we aimed to develop a simpler and effective molecular epidemiological technique based on the open-reading frame (ORF) distribution patterns detected by PCR, which we call PCR-based ORF typing (POT). METHODS AND RESULTS: Ten ORFs from genomic islets, five ORFs from genomic islands, and the metallo-ß-lactamases (MBLs) blaIMP and blaVIM were selected by comparing the whole-genome sequences of different Ps. aeruginosa strains (PAO1, PA7, UCBPP-PA14 and LESB58). These 17 ORFs were detected, along with a Ps. aeruginosa marker, using 9-plex and 10-plex PCR systems. The genotypes in the POT were compared to those obtained by using PFGE and MLST. CONCLUSIONS: Using the POT method, molecular epidemiological analyses of Ps. aeruginosa can be completed in 4 h. SIGNIFICANCE AND IMPACT OF THE STUDY: Since this method is very easy to perform, even in standard clinical laboratories, it could be a valuable tool for monitoring daily infection control measures.

Genetic relatedness of Mycobacterium avium-intracellulare complex isolates from patients with pulmonary MAC disease and their residential soils.

Mycobacterium avium-intracellulare complex (MAC) strains were recovered from 48.9% of residential soil samples (agricultural farms (n = 7), residential yards (n = 79), and planting pots (n = 49)) of 100 pulmonary MAC patients and 35 non-infected control patients. The frequency of MAC recovery did not differ among soil types or among patients regardless of the presence of pulmonary MAC disease, infecting MAC species or period of soil exposure. Variable numbers of tandem repeats (VNTR) analysis for MAC clinical and soil isolates revealed 78 different patterns in 47 M. avium clinical isolates and 41 soil isolates, and 53 different patterns in 18 M. intracellulare clinical isolates and 37 soil isolates. Six clinical and corresponding soil isolate pairs with an identical VNTR genotype were from case patients with high soil exposure (≥2 h per week, 37.5% (6/16) with high exposure compared with 0.0% (0/19) with low or no exposure, p <0.01), suggesting that residential soils are a likely source of pulmonary MAC infection.

Sulfate radical-initiated formation of isoprene-derived organosulfates in atmospheric aerosols.

Recent studies show that isoprene-derived organosulfates are an important fraction of ambient secondary organic aerosol (SOA), adding up to 20% to the organic mass. Organosulfates with m/z of 199 and 183 relating to C4 compounds are found in ambient and laboratory generated SOA and a sulfate radical induced oxidation of methacrolein (MACR) and methyl vinyl ketone (MVK) has been shown to be a possible formation mechanism. In the present study, experiments on the sulfate radical-induced oxidation of methacrolein and methyl vinyl ketone were performed in bulk aqueous phase, as well as in an aerosol chamber, and finally compared with ambient PM10 samples collected at a rural East German village during the summer 2008, to investigate their relevance in aqueous phase SOA formation. Samples from aqueous phase experiments and extracts from filters were analysed with UPLC/(-)ESI-IMS-QTOFMS. All the samples showed the abundance of highly oxidised organosulfates with m/z 153, 155, 167, 183 and 199 corresponding to the species found in ambient particle samples. In the bulk phase studies with laser-induced sulfate radical formation, the signal intensities increased with increasing number of laser pulses, indicating the sulfate radical-induced formation of these organosulfates. Additionally, the chamber experiments showed a particle mass growth of about 10 microg m(-3) and 4 microg m(-3) for experiments on the reactive uptake of MACR and MVK with a sulfate radical precursor (K2S2O8) in the seed particles. Correlations of the C2 to C5 organosulfate species (including the m/z 215, C5H11O7S-), detected in the ambient samples were found to be very strong (r > 0.8), indicating that these compounds are formed from similar mechanisms and under equal environmental conditions. This study shows that sulfate radical-induced oxidation in the aqueous particle phase provides a reasonable explanation for the formation of these organosulfates from methacrolein and methyl vinyl ketone.

Regional spread and control of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis in Kyoto, Japan.

The purpose of this investigation was to control the post-outbreak prevalence of vancomycin-resistant enterococci (VRE) in the affected Kyoto region. The study period was from 2005 to 2010. Faecal samples were subjected to VRE screening, and vancomycin resistance genes were detected by polymerase chain reaction (PCR). The genotype was determined by pulsed-field gel electrophoresis (PFGE) of genomic DNA digested with SmaI and by multilocus sequence typing (MLST). A VRE control programme was established in 2006, consisting of a laboratory-based faecal VRE screening system, annual surveillance of hospital inpatients and the promotion of adequate infection control measures. vanA-Enterococcus faecium, vanB-E. faecium and vanB-E. faecalis were detected at 35, 12 and 5 hospitals, respectively. Genotype analysis revealed that all of the vancomycin-resistant E. faecium isolates obtained since 2005 belonged to ST78, and that clonally related vanB-E. faecalis of ST64 had spread to three hospitals. The rate of faecal VRE carriage among the patients enrolled in the annual surveillance increased until 2007, when it reached 24 (1.2%) of the 2,035 enrolled patients. The rate began to decrease in 2008 and, by 2010, reached a low of 4 (0.17%) of the 2,408 enrolled patients. While VRE did spread within the Kyoto region, the VRE control programme succeeded in controlling the overall VRE spread.

Quantitative real-time PCR and the (1→3)-ß-D-glucan assay for differentiation between Pneumocystis jirovecii pneumonia and colonization.

We evaluated whether quantitative PCR (qPCR) and (1 → 3)-ß-d-glucan assays could be used to differentiate Pneumocystis pneumonia (PCP) from Pneumocystis jirovecii colonization in immunocompromised patients with pulmonary infiltrates. A total of 40 bronchoalveolar lavage samples and 107 induced sputum samples from 147 patients who were suspected of having PCP were obtained for PCR detection of P. jirovecii. Diagnoses of definite PCP, probable PCP, pneumonia with P. jirovecii colonization (colonization) and pneumonia without colonization (non-colonization) were made in 11, 42, 15 and 60 patients, respectively. A PCP diagnosis was undetermined in 19 patients. The copy numbers, determined using qPCR, were significantly higher in definite PCP and probable PCP patients than in colonized patients. The area under the receiver-operating characteristic curve (AUC), sensitivity and specificity for discriminating definite PCP from colonization were 0.96, 100.0% and 80.0%, respectively, at a cut-off value of 1300 copies/mL. The values for discriminating probable PCP from colonization were 0.71, 66.7% and 73.3%, respectively, at a cut-off value of 340 copies/mL. ß-d-glucan levels were significantly higher in patients with both definite PCP and probable PCP than in colonized patients. The AUC, sensitivity and specificity for discriminating definite PCP were 0.91, 100.0% and 80.0%, respectively, at a cut-off value of 15.6 pg/mL. The values for discriminating probable PCP were 0.78, 76.2% and 73.3%, respectively, at a cut-off value of 6.0 pg/mL. Both qPCR and the ß-d-glucan assay displayed high accuracy for discriminating colonization from definite PCP and displayed moderate accuracy for discriminating colonization from probable PCP.

Control of an outbreak of carbapenem-resistant Pseudomonas aeruginosa in a haemato-oncology unit.

An outbreak of a multidrug-resistant Pseudomonas aeruginosa producing metallo-ß-lactamase (MBLPA) in a haemato-oncology unit was controlled using multidisciplinary interventions. The present study assesses the effects of these interventions by active surveillance of the incidence of MBLPA infection at the 1,240-bed tertiary care Kyoto University Hospital in Kyoto, Japan. Infection control strategies in 2004 included strengthening contact precautions, analysis of risk factors for MBLPA infection and cessation of urine collection. However, new MBLPA infections were identified in 2006, which prompted enhanced environmental cleaning, routine active surveillance, and restricting carbapenem usage. Between 2004 and 2010, 17 patients in the unit became infected with indistinguishable MBLPA strains. The final five infected patients were found by routine active surveillance, but horizontal transmission was undetectable. The MBLPA outbreak in the haemato-oncology unit was finally contained in 2008.

Interferon-gamma release assay for diagnosing Mycobacterium tuberculosis infections in patients with systemic lupus erythematosus.

Our aim was to analyze the performance of an interferon-gamma release assay, QuantiFERON-TB Gold (QFT-2G), for diagnosing Mycobacterium tuberculosis (MTB) infection in patients with systemic lupus erythematosus (SLE). We performed the QFT-2G and tuberculin skin test (TST) in 71 SLE patients. The QFT-2G results of 279 patients with other connective tissue diseases (CTD) and 35 healthy controls were analyzed. Of the 71 SLE patients, two (2.8%) were positive and 46 (64.8%) were negative by QFT-2G. All SLE patients had no evidence of active MTB infection, apart from one. QFT-2G produced a significantly higher number of indeterminate results in patients with SLE (23/71, 32.4%) compared with those with other CTD (5.7%) or healthy controls (0%) (p < 0.0001 and p < 0.0001). Decreased lymphocyte counts and high SLEDAI scores in SLE patients were shown to be risk factors for indeterminate results by multivariate analysis (p = 0.02 and p = 0.04). Among all patients with CTD, SLE itself and lymphocytopenia were found to be independent risks for indeterminate results (p = 0.00000625 and p = 0.000107). In conclusion, QFT-2G may have more potential to assist in the diagnosis of active and latent MTB infection than TST in SLE patients. However, because of the high frequency of indeterminate results, caution must be used when interpreting the results of QFT-2G among SLE patients, especially those who have parallel or subsequent flares.

Regional spread of vanA- or vanB-positive Enterococcus gallinarum in hospitals and long-term care facilities in Kyoto prefecture, Japan.

Following an outbreak of vanA-positive Enterococcus faecium in 2005 in Kyoto prefecture, regional surveillance of vancomycin-resistant enterococci (VRE) was initiated. This revealed vanA- or vanB-positive Enterococcus gallinarum in multiple facilities. Eighty-eight vanA-positive E. gallinarum faecal carriers from 12 facilities and ten vanB-positive E. gallinarum faecal carriers from eight facilities were found. Pulsed-field gel electrophoresis profiles of the first isolate from each facility showed that 11 of the 12 vanA isolates and three of the eight vanB-positive E. gallinarum isolates belonged to a single clone. This study confirms the clonal spread of vanA- or vanB-positive E. gallinarum in a region and underlines the importance of surveillance of VRE for the presence of vancomycin resistance determinants.

Distribution and clonal relationship of cell surface virulence genes among Streptococcus pneumoniae isolates in Japan.

Streptococcus pneumoniae resides on mucosal surfaces in the nasopharynx, where selection for horizontal transfer of antimicrobial resistance genes and virulence factors may provide a survival advantage. We investigated the distribution of genes for pneumococcal cell surface proteins and their correlations with multilocus sequence typing (MLST), Pneumococcal Molecular Epidemiology Network (PMEN) clones and antimicrobial resistance, to identify pneumococcal virulence factors predicting prevalent clones from 156 pneumococcal isolates recovered from adult patients with community-acquired pneumonia in Japan. Pneumococcal eno, pavA, piuA, cbpA and cbpG were present in all isolates, and hyl and piaA were distributed among the clinical isolates. In contrast, pneumococcal rlrA, pclA, psrP, nanC and pspA family 1-type genes were variably distributed and significantly associated with MLST (Wallace coefficients (W) were over 84%). Serotype was a weaker predictor of sequence type (W, 0.75) than vice versa (W, 0.97). A multiple logistic regression analysis adjusted to the presence of virulence genes, pspA family 1 genes and carriage serotypes revealed that pclA and rlrA correlated with PMEN clones and antimicrobial resistance, and are likely to contribute to the selection of prevalent clones.

Intrauterine fetal demise due to streptococcal toxic shock syndrome: a case report.

BACKGROUND: Toxic shock syndrome caused by group A streptococci (GAS) is rare around the time of delivery, but it may predispose pregnant women to a life-threatening condition. CASE: A 32-year-old primigravida at 21 weeks of gestation was taken to our hospital with acute severe abdominal pain following fever. On admission the fetus was found to be dead, and intrauterine fetal demise due to placental abruption was suspected. An emergency cesarean section found no sign of placental abruption. Soon after the surgery, the patient went into shock but was successfully treated with intensive care. Although repeated blood cultures failed to detect microorganisms, the patient was positive for streptococcal pyrogenic toxin A, which is a superantigen of GAS. CONCLUSION: Once GAS infection is suspected, regardless of negative blood cultures, supportive care in the intensive care unit is mandatory.

Close cooperation between infectious disease physicians and attending physicians can result in better management and outcome for patients with Staphylococcus aureus bacteraemia.

Staphylococcus aureus bacteraemia (SAB) is a serious infection that demands prompt clinical attention for good outcome. To assess the impact of intervention by infectious diseases physicians (IDPs) in cases with SAB, a retrospective cohort study of patients with SAB was performed in a 1240-bed, university hospital in Japan, with the aim of comparing the management and outcome of patients during the initial and the latter half of the intervention period,. Three hundred and forty-six patients with SAB during the 7-year period, from 2002 to 2008, were included, and 194 patients in the initial half of the period (from 2002 to 2005) were compared with 152 patients in the later period (from 2006 to 2008). There was no significant difference between the two groups with respect to patient's clinical background, although more patients in the later period were receiving immunosuppressive treatment. The proportion of methicillin resistant S. aureus was lower during the later period (56.2% vs. 43.3%; p 0.02). Echocardiography was used more frequently (37.1% vs. 64.5%; p < 0.001). Infective endocarditis and metastatic infections were diagnosed more frequently (10.8% vs. 20.4%; p 0.01). Follow-up blood cultures were obtained more regularly (52.1% vs. 73.7%; p <0.001) and therapy was more frequently administered for at least 14 days (47.4% vs. 82.2%; p <0.001). The 30-day mortality improved during the intervention period (25.8% vs. 16.4%; p 0.04). The total number of blood cultures received by the laboratory increased annually and the total number of consultations increased by approximately 1.6-fold compared to 2002. Proactive intervention by IDPs raised awareness of optimal management of bacteraemia and improved the adherence to the standards of care, which subsequently resulted in an improvement in the outcome.

High prevalence of mutators among Enterobacter cloacae nosocomial isolates and their association with antimicrobial resistance and repetitive detection.

We determined the mutation frequencies of 59 nosocomial isolates of Enterobacter cloacae, and investigated their association with antimicrobial susceptibility, genotype, and history of exposure to antimicrobials. The frequencies of mutations leading to rifampicin resistance ranged from 5.8 × 10(-9) to 8.0 × 10(-6) (median, 5.0 × 10(-8)). Seven of the 59 (12%) isolates were graded as strong mutators exhibiting a more than 50-fold increase in the mutation frequency relative to that of E. cloacae ATCC 13047, and 30 (52%) were graded as weak mutators exhibiting a more than five-fold and not more than 50-fold increase in the mutation frequency. The isolates with higher grade of mutation frequency were resistant to significantly more antimicrobials (medians of two, one and zero agents for strong mutators, weak mutators and non-mutators, respectively; p 0.0078). The 59 isolates were classified into 36 genotypes, and all of the seven strong mutators had distinct genotypes. Mutation frequencies varied more than 10(2)-fold within a clone. In patient-based, univariate analysis, intensive-care unit admission, dense antimicrobial exposure (glycopeptide or multiple classes) and repetitive detection of this species were significantly more common among all of the four patients from whom strong mutators were obtained. Strong mutators are highly prevalent in surgical isolates of E. cloacae. Higher mutation frequency was associated with antimicrobial resistance and repetitive detection, and may contribute to the adaptability of this species.

Atmospheric stability of levoglucosan: a detailed laboratory and modeling study.

Levoglucosan, an important molecular marker for biomass burning, represents an important fraction of the water-soluble organic carbon in atmospheric particles influenced by residential wood burning and wildfires. However, particle phase oxidation processes of levoglucosan by free radicals are not well-known. Hence, detailed kinetic studies on the reactivity of levoglucosan with OH, NO(3), and SO(4)(-) radicals in aqueous solutions were performed to better understand the levoglucosan oxidation in the deliquescent particles. The data obtained were implemented into a parcel model with detailed microphysics and complex multiphase chemistry to investigate the degradation fluxes of levoglucosan in cloud droplets and in deliquescent particles. The model calculations show that levoglucosan can be oxidized readily by OH radicals during daytime with mean degradation fluxes of about 7.2 ng m(-3) h(-1) in summer and 4.7 ng m(-3) h(-1) in winter for a polluted continental plume. This indicates that the oxidation of levoglucosan in atmospheric deliquescent particles is at least as fast as that of other atmospherically relevant organic compounds and levoglucosan may not be as stable as previously thought in the atmosphere, especially under high relative humidity conditions.

Quantification of organic acids in particulate matter by coupling of thermally assisted hydrolysis and methylation with thermodesorption-gas chromatography-mass spectrometry.

A quantitative method for the determination of organic acids in atmospheric particles is developed. The method couples a derivatisation step (thermally assisted hydrolysis and methylation) and a Curie point pyrolyser as a thermal desorption technique and gas chromatography-mass spectrometry (CPP-GC-MS). Among the reagents tested (tetramethylammonium hydroxide (TMAH), tetramethylammonium acetate (TMAAc) and phenyltrimethylammonium hydroxide (TMPAH)), the best performance was found using TMAAc as a derivatisation reagent for the reaction time of 4s at 510 degrees C as heating temperature. Calibration was performed for a series of fatty acids (FA), dicarboxylic acids (DCA) and terpenoic acids (TA) under these conditions. Coefficients of determination (R(2)) were between 0.94 and 0.98. Limits of detection (LOD) were in the nanogram-range between 0.1 and 3.6 ng. The method is applied on atmospheric particle samples to obtain the quantification reproducibility and quantification limits. Reproducibility was determined in terms of relative standard deviations (RSD) for ambient aerosol samples collected by a high-volume-sampler (HVS, RSD=6-45%, n=10) and a Berner impactor (BI, RSD=5-34%, n=10). Based on 24h sampling time the developed method enables quantification of all three classes of acids for both sampling techniques. Calibration data and presented volume concentrations are compared with literature data. A comparison with an off-line methylation-GC-MS using BF(3) as a derivatisation reagent and capillary electrophoresis coupled mass spectrometry (CE-MS) showed a good agreement. Minimal sample preparation is the main advantage of the developed method. Depending on the sensitivity requirements the present method can be a fast and simple alternative to GC-MS techniques with conventional sample preparation steps for semi-volatile organic acids.

High prevalence of multidrug-resistant Pneumococcal molecular epidemiology network clones among Streptococcus pneumoniae isolates from adult patients with community-acquired pneumonia in Japan.

A total of 141 Streptococcus pneumoniae isolates from patients with community-acquired pneumonia were collected from May 2003 through October 2004. The strains were tested for antimicrobial agent susceptibility, serotype and genotype by multilocus sequence typing (MLST) and the presence of the pilus rlrA islet. MLST analysis identified 49 sequence types (STs), of which 19 were novel. eBURST analysis using the MLST database (3773 STs) grouped the isolates into 27 clonal complexes and three singletons. A total of 92 (65.2%) isolates were related to ten of the 43 international Pneumococcal Molecular Epidemiology Network (PMEN) clones; major clones found were multidrug-resistant Netherlands(3)-31 [clonal complex (CC) 180], Taiwan(19F)-14 (CC271), Taiwan(23F)-15 (CC242), and Colombia(23F)-26 (CC138) (the latter new to Asia). We adopted univariate and multiple logistic regression models to identify factors associated with PMEN CCs. Multivariate analysis showed that multidrug resistance (OR 6.3; 95% CI 2.0-22.9), carriage serogroups (OR 7.2; 95% CI 2.5-23.7), prevalence of rlrA (OR 12.6; 95% CI 3.6-59.7) and central nervous system-related disorders (OR 7.7; 95% CI 1.8-48.4) were independently associated with PMEN CCs. Our data indicate that multidrug-resistant PMEN clones are highly prevalent, contributing to the high frequency of resistance to antimicrobial agents in Japan, and suggest that certain predisposing factors in patients contribute to the high frequency of these clones.

Effects on spectrum and susceptibility patterns of isolates causing bloodstream infection by restriction of fluoroquinolone prophylaxis in a hematology-oncology unit.

The emergence of fluoroquinolone-resistant gram-negative organisms has been demonstrated in patients given fluoroquinolone prophylaxis. To prevent increases in resistant bacteria, we restricted prophylactic use of fluoroquinolones. The spectrum and susceptibility patterns of isolates causing bloodstream infection (BSI) were assessed in patients receiving chemotherapy during periods of routine prophylaxis (period A: October 2001 to May 2003) and restricted prophylaxis (period B: June 2003 to January 2005). The total number of patients receiving chemotherapy was 442 during period A and 365 during period B. No significant differences were seen between periods with respect to patient characteristics. BSI was identified in 42 patients (44 episodes) during period A and 69 patients (74 episodes) during period B. Incidence of BSI increased significantly from 10.0% (44/442) during period A to 20.3% (74/365) during period B (P < 0.0001). Rate of Enterobacteriaceae BSI increased significantly, from 2.0% (9/442) during period A to 8.2% (30/365) during period B (P < 0.0001). For all BSI episodes, the proportion of BSI with gram-positive cocci decreased from 63.6% (28/44) during period A to 44.6% (33/74) during period B (P = 0.045), while the proportion of BSI with Enterobacteriaceae increased from 20.5% (9/44) to 40.5% (30/74) (P < 0.0001). The proportion of fluoroquinolone-resistant Enterobacteriaceae BSI for all Enterobacteriaceae BSI decreased from 75% (9/12) during period A to 17% (5/30) during period B (P = 0.0078). Restriction of fluoroquinolone prophylaxis affects the etiology of BSI and reduces the proportion of drug-resistant organisms.