Panton–Valentine leukocidin (PVL)-positive methicillin-susceptible and resistant Staphylococcus aureus in Taiwan: identification of oxacillin-susceptible mecA-positive methicillin-resistant S. aureus

Methicillin-resistant Staphylococcus aureus (MRSA) arises when methicillin-susceptible S. aureus (MSSA) acquires the staphylococcal cassette chromosome mec (SCCmec). Most pvl-positive MRSA in Taiwan belong to ST59 lineage and carry SCCmec V. The genetic profiles of 51 MSSA were compared with those of 80 MRSA from the same hospitals. Nine pvl-positive MSSA (oxacillin MIC ≤2 μg/mL) shared >80% similarity in pulsed field gel electrophoresis pattern with 17 pvl-positive SCCmec V MRSA. Further investigation found that 5 of these 9 isolates were MRSA by cefoxitin and carried SCCmec V. All 26 pvl-positive isolates had very similar genetic profile (ST59, protein A clonal complex [spa-CC] c2:441/437, and agr group I). The success of the ST59:SCCmec V MRSA may be due in part to its heterogeneous and borderline resistance to methicillin, which may be missed by testing only oxacillin, with subsequent exposure to β-lactams causing the emergence of more resistant subpopulations.     

CTX-M and ampC β-lactamases contributing to increased prevalence of ceftriaxone-resistant Escherichia coli in Changi General Hospital,Singapore

Data from an 800-bed hospital showed an increase in the incidence density of ceftriaxone-resistant Escherichia coli, from 13.1 to 21.7 per 100?000 inpatient days over a 4-year period. Detailed testing performed on 54 E. coli isolates showed bla_CTX-M extended-spectrum β-lactamase (ESBL) genes (n = 37) and bla_CMY-likeampC genes (n = 15). Typing data showed only limited clonal transmission in isolates with ESBL.     

Preventing Pasung by mentally ill patients’ families

Pasung is a way of handling the mentally ill in the several Indonesian communities. In many cases, when the patients leave the hospital they are once again turned out by their families and returned to the pasung. This study aims to identify and explore the means of preventing mentally ill patients in the community from being subjected to pasung through a test of Daulima's Pasung Decision Questionnaire that measures a family's intention to use pasung. This study tested the content validity and reliability of Daulima's Pasung Decision Questionnaire by using the Spearman-Brown single test-single trial. The respondents were 300 people drawn from five provinces in Indonesia: West Sumatra, East Kalimantan, West Nusa Tenggara, West Java and the Special Capital Region of Jakarta. The validity and reliability results showed that the content of this instrument is valid once improvements had been made to the statement items numbers 16 and 17. It was also shown to be reliable by the consistency of the responses with an alpha value of 0.729. This means that responses to the instrument are consistent and are reliable measures of the level of intention of the mentally ill patient's family to use pasung.     

Spread of CTX-M–type extended-spectrum β-lactamases among bloodstream isolates of Escherichia coli and Klebsiella pneumoniae from a Korean hospital

This study was to determine the prevalence and characteristics of CTX-M–type extended-spectrum β-lactamases (ESBLs) in nonduplicate Escherichia coli (n = 760) and Klebsiella pneumoniae (n = 379) bloodstream isolates collected during January 2005 to October 2007 at a university hospital (2000 beds) in Seoul, Korea. Antimicrobial susceptibilities were determined by disk diffusion and agar dilution methods. The double-disk synergy test detected ESBLs in 8.7% (66/760) of E. coli and 11.3% (43/379) of K. pneumoniae isolates. Polymerase chain reaction detected bla_CTX-M in 60/66 (90.9%) E. coli and 9/43 (20.9%) K. pneumoniae isolates with the ESBL phenotype. CTX-M-14 was the most common type of CTX-M ESBLs in both E. coli (n = 32) and K. pneumoniae (n = 6). CTX-M-15 was the 2nd most common type of CTX-M ESBLs in E. coli (n = 22), but it was not detected in K. pneumoniae. In addition, CTX-M-24 (n = 2), CTX-M-65 (n = 2), CTX-M-27 (n = 1), and CTX-M-32 (n = 1) were detected for the 1st time in Korea.     

单增李斯特菌EGD-e基因组的密码子使用分析

目的 以单增李斯特菌EGD-e为研究对象,分析其密码子使用模式及影响因素。 方法 利用Codon W在线工具分析单增李斯特菌EGD-e基因组的密码子使用情况;利用对应分析、ENC绘图(Nc-plot)等推测影响单增李斯特菌EGD-e密码子偏性的因素;利用高表达优越密码子分析法确定单增李斯特菌EGD-e基因组的主要偏爱密码子。 结果 单增李斯特菌EGD-e基因组中G+C含量仅为37%,偏爱使用以U或A结尾的密码子;对应分析显示第1条向量轴与G+C(R=-0.182, P0.01)、CAI(R=-0.740, P0.01)呈显著相关,且与后者的相关程度明显高于前者。 结论 单增李斯特菌EGD-e基因组的密码子使用具有一定的偏性;推测基因的表达水平是影响单增李斯特菌EGD-e基因组密码子使用的主要因素。同时,基因组密码子使用偏性还受到碱基组成的影响,而基因长度对密码子的使用偏性影响不大。最后确定了UUC、UUA等27个密码子为单增李斯特菌EGD-e的最优密码子。这些结果将为进一步研究单增李斯特菌的基因组学提供基础。     

GMDP augments antitumor action of the CP/TNFα combination in vivo

We have shown that glucosaminyl muramyl dipeptide (GMDP) has been augmented the antitumor action of chemotherapy drug cisplatin and tumor necrosis factor-α (TNFα) on the Ehrlich ascites carcinoma and melanoma B-16 mouse tumor models. The doses of cisplatin, TNFα and GMDP and also the conditions of the drugs combination injection provided 100% survival of mice with Ehrlich ascites carcinoma were found. Furthermore, it was shown first that GMDP has been decreased toxicity of the cisplatin/TNFα combination and normalized the changes in the experimental mice hematological parameters which were produced by the CP/TNFα combination.     

Changing prevalence of Escherichia coli with CTX-M–type extended-spectrum β-lactamases in outpatient urinary E. coli between 2003 and 2008

One hundred ninety-three single-patient isolates of Escherichia coli harboring extended-spectrum β-lactamases (ESBL) were identified among 11?407 E. coli urine isolates recovered from single-patient outpatient urine cultures from 2003 to 2008. The percentage of ESBL-producing E. coli among community-onset E. coli urine isolates increased from 0.21% in 2003 to 2.99% in 2008. One hundred seven of the ESBL producers were positive for the presence of bla_CTX-M genes. The percentage of CTX-M–producing E. coli rose from 0.07% in 2003 to 1.66% in 2008. The annual percentage of ESBL E. coli producing CTX-Ms changed from 35% in 2003 to 64% in 2008. Genes belonging to 3 bla_CTX-M groups: bla_CTX-M-1 group, bla_CTX-M-2 group, and bla_CTX-M-9 group, were detected. In addition, resistance to commonly used antimicrobial agents for community-acquired urinary tract infections was found common among CTX-M–producing E. coli isolates. Ertapenem and nitrofurantoin showed good in vitro activity against CTX-M producers.     

Comparison of real-time polymerase chain reaction and conventional biochemical methods for identification of Mycobacterium chelonae–Mycobacterium abscessus group to the species level

The Mycobacterium chelonae–Mycobacterium abscessus group (MCAG) is the most common cause of infections because of rapidly growing mycobacteria. Rapid identification of MCAG to the species level is essential for choosing empiric antibiotic treatment and for public health measures. In this study, we compared the performance of a single-tube multiplex, real-time polymerase chain reaction (PCR) assay to 3 biochemical tests for species-level identification of 46 MCAG isolates. We show that real-time PCR provides the most accurate results for rapid species-level identification of MCAG.     

Recurrent peritoneal dialysis–related peritonitis caused by Microbacterium resistens

We report a case of a recurrent peritonitis due to Microbacterium resistens in a 71-year-old male patient undergoing peritoneal dialysis (PD). Importantly, this Gram-positive rod was intrinsically resistant to cephalosporins and vancomycin, classically used in PD-related peritonitis treatment. His infection resolved after several weeks of appropriate therapy (amoxicillin plus gentamicin) and PD catheter removal.     

Killing of Escherichia coli by β-lactams at different inocula

Escherichia coli is a common pathogen implicated in intra-abdominal infections; a heavy bacterial burden is often encountered, and the clinical utility of β-lactams may be limited by the inoculum effect. We examined the impact of a high inoculum on the bactericidal activity of various β-lactams against E. coli. Two wild-type, an extended-spectrum β-lactamase–producing, and a plasmid-mediated AmpC-producing strains, were used. Clinically achievable concentrations of piperacillin/tazobactam, ceftriaxone, and ertapenem were investigated. Viable bacterial burden was serially determined for 24 h by quantitative culture. All 3 β-lactams demonstrated significant killing against the standard inoculum (10⁵ CFU/mL) of susceptible strains. However, the activity of piperacillin/tazobactam was drastically reduced with 10⁸ CFU/mL of bacteria. Ertapenem was the least affected by the inoculum effect in all strains. Our results suggest that different β-lactam subclasses have a distinct killing profile against a dense E. coli population. Comparative in vivo/clinical investigations are warranted to validate our findings.     

In vitro efficacy of 5 antifungal agents against Candida parapsilosis,Candida orthopsilosis, and Candida metapsilosis as determined by time–kill methodology

Killing activity of amphotericin B, fluconazole, voriconazole, posaconazole, and 5-fluorocytosine was determined against 6 Candida parapsilosis, 3 Candida orthopsilosis, and 4 Candida metapsilosis clinical isolates. After 24 h, 1 of 6 C. parapsilosis, 1 of 3 C. orthopsilosis, and 3 of 4 C. metapsilosis isolates were killed at 1 to 4 μg/mL (1–8× MIC) amphotericin B. The remaining isolates were killed by 2 to 4 μg/mL amphotericin B after 48 h. Fluconazole was fungistatic at ≥1× MIC (0.5–2 μg/mL) against C. parapsilosis and at ≥2× MIC (4–8 μg/mL) against C. orthopsilosis and C. metapsilosis isolates. Voriconazole inhibited C. parapsilosis at ≥1× MIC (0.015–0.12 μg/mL), but the other 2 species were inhibited only at 4 to 8× MIC (0.25–0.5 μg/mL). Against C. orthopsilosis and C. metapsilosis, posaconazole was fungistatic close to the MIC (0.03–0.06 and 0.015–0.03 μg/mL, respectively). Against C. orthopsilosis and C. metapsilosis, fluconazole and voriconazole, but not posaconazole, seem to be less active in vitro than against C. parapsilosis.     

In vitro–in vivo correlation of voriconazole resistance due to G448S mutation (cyp51A gene) in Aspergillus fumigatus

Invasive pulmonary aspergillosis continues to be associated with a high mortality despite timely and appropriate therapy. Although host immunity plays a major role in poor clinical response, antifungal drug resistance cannot be ignored. Our studies were aimed 1) to study the mechanism of drug resistance in voriconazole strains of Aspergillus fumigatus, 2) to establish a causal relationship between cyp51A mutation and voriconazole resistance (VRC-R), and 3) to determine whether VRC-R due to cyp51A mutation correlated with in vivo resistance. A point mutation (G448S) involving cyp51A gene in VRC-R isolate was associated with resistance to VRC but not to posaconazole (POS); POS had superior activity to VRC in reducing lung fungal burden and mortality in mice infected with a VRC-R mutant of A. fumigatus. Our study demonstrated that azole resistance is based on specific site of cyp51A mutation and that in vitro VRC-R correlates with in vivo resistance.     

Evaluation of drug delivery profiles in geometric three-layered tablets with various mechanical properties, in vitro–in vivo drug release,and Raman imaging

Even though various multi-layered tablets have been developed for sustained release formulations, evaluations of mechanical properties during dissolution with drug release and imaging in the tablets have been limited. A novel geometric system consisting of an inner immediate release layer and two extended release barrier layers with swellable hydrophilic polymers was suggested as a once-a-day formulation. To evaluate drug release mechanisms with geometric properties, various mechanical characteristics during swelling were investigated to comprehend the relationship among in vitro drug release, human pharmacokinetics, and geometric characteristics. Imaging of drug movement was also studied in real-time using Raman spectroscopy. Drug delivery in the tablets might be divided into three processes through the geometric properties. When exposed to aqueous environments, the drug in the mid-layer was released until wrapped by the swollen barrier layers. Then, the drug in the mid-layer was mainly delivered to the barrier layers and a small amount of the drug was delivered to the contact region of the swollen barrier layers. Finally, the delivered drug to the barrier layers was consistently released out in response to the characteristics of the polymer of the barrier layers. Using Raman spectroscopy, these processes were confirmed in real-time analysis. Moreover, in vitro drug release profiles and human pharmacokinetics showed consistent results suggesting that drug release might be dependent on the various geometric properties and be modified consistently during the formulation development.     

USA300 methicillin-resistant Staphylococcus aureus bacteremia and the risk of severe sepsis: is USA300 methicillin-resistant Staphylococcus aureus associated with more severe infections?

USA300 methicillin-resistant Staphylococcus aureus (MRSA) is increasing as a cause of severe community-associated bacteremic infections. We assessed severe sepsis in response to infection in patients with USA300 MRSA compared to non-USA300 MRSA bacteremia. A cohort study was conducted from 1997 to 2008 comparing sepsis in response to infection in 271 patients with MRSA bacteremia from 4 VA hospitals. Sixty-seven (25%) patients with MRSA bacteremia were USA300 MRSA; 204 (75%) were non-USA300 MRSA. The proportion of MRSA bacteremia caused by USA300 MRSA increased over time (χ2 P < 0.0001). Adjusting for age and nosocomial infection, patients with USA300 MRSA bacteremia were more likely to have severe sepsis or septic shock in response to infection than patients with non-USA300 MRSA bacteremia (adjusted relative risk = 1.82; 95% confidence interval, 1.16-2.87; P = 0.01). This suggests that patients with USA300 MRSA are more likely to develop severe sepsis in response to their infection, which could be due to host or bacterial differences.     

灰阶超声诊断甲状腺微小乳头状癌的Logistic回归分析

目的 探讨甲状腺微小乳头状癌的灰阶超声恶性征象,评价其应用价值。方法 回顾性分析经过手术病理证实的378个甲状腺微小结节(其中良性137个,恶性241个)的灰阶超声表现,通过Logistc回归分析筛选微小结节的恶性征象,并建立Logistic回归模型。结果 Logistic回归分析显示最后进入回归模型的是微小结节的纵横比、内部结构、形态、边界、与甲状腺被膜关系、声晕及钙化类型。Logistic模型以预测概率P=0.50作为阈值,准确率达84.40%,ROC曲线下面积为0.91。结论 以甲状腺微小结节的纵横比、内部结构、形态、边界、与甲状腺被膜关系、声晕及钙化类型7个诊断参数变量建立的Logistic回归模型有助于甲状腺微小乳头状癌的鉴别诊断。     

Evidence for qnrB1 and aac(6′)-Ib-cr in CTX-M-15–producing uropathogenic Enterobacteriaceae in an Italian teaching hospital

In this work, we report the spread of CTX-M–producing uropathogenic ciprofloxacin-resistant Enterobacteriaceae. This is the first identification in Italy of the simultaneous presence of aac(6′)-Ib-cr, qnrB1, and bla_CTX-M-15 resistance determinants in an Escherichia coli strain isolated from urine of a nonhospitalized patient.     

Can mailed swab samples be dry-shipped for the detection of Chlamydia trachomatis,Neisseria gonorrhoeae, and Trichomonas vaginalis by nucleic acid amplification tests?

Dry-shipped and mailed vaginal swabs collected at home have been used in research studies for the detection of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (GC), and Trichomonas vaginalis (TV) by nucleic acid amplification tests (NAATs) in screening programs. A verification study was performed to compare the limit of detection of CT, GC, and TV on swabs that were dry-shipped to paired swabs that were wet-shipped in transport media through the US mail. The Centers for Disease Control and Prevention prepared inocula in sterile water to mock simulated urogenital swabs with high to low concentrations of CT and GC. Replicate swabs were inoculated with 100 μL of dilutions and were dry transported or placed into commercial transport media ("wet") for mailing for NAAT testing. The University of Alabama prepared replicate concentrations of TV, which were similarly shipped and tested by NAAT. All paired dry and wet swabs were detectable for CT. For GC, all paired dry and wet swabs were detectable for GC at concentrations ≥ 10(3). At 10(2) and 10 CFU/mL, the 10 replicate GC results were variably positive. For TV, wet and dry shipped concentrations >10(2) TV/mL tested positive, while results at 10 TV/mL were negative for dry swabs. Holding replicate dry swabs at 55 (○)C 5 days before testing did not affect results. NAATs were able to detect CT, GC, and TV on dry transported swabs. Using NAATs for testing home-collected, urogenital swabs mailed in a dry state to a laboratory may be useful for outreach screening programs.     

False-positive Aspergillus antigen testing due to application of piperacillin/tazobactam-is it still an issue?

We evaluated the impact of piperacillin/tazobactam (PT) therapy on galactomannan enzyme immunoassay (GEI) testing (Platelia; Bio-Rad, Marnes La Coquette, France). Galactomannan contents of PT batches were highly variable. We found that false-positive GEI results can be avoided by performance of blood sampling before PT administration and by using separate sites for blood sampling and for administration of antibiotics.