Evaluation of the modified carbapenem inactivation method for the detection of carbapenemase-producing Enterobacteriaceae.

Carbapenemase-producing Enterobacteriaceae (CPE) are increasing worldwide. Rapid and accurate detection of CPE is necessary for appropriate antimicrobial treatment and hospital infection control. However, CPE contains some strains that are difficult to detect depending on genotype and MIC value of carbapenem, and a detection method has not been established. The recently reported modified carbapenem inactivation method (mCIM) has been developed in CLSI M100-S27 as a phenotypic technique for detecting carbapenemase activity. In the present study, we examined mCIM as a new CPE detection method using 207 Enterobacteriaceae isolates in comparison with the three existing screening methods of modified Hodge test, Carba NP test and carbapenem inactivation method and evaluated its performance. Consequently, both the sensitivity and specificity of mCIM were 100%, indicating better results than the conventional screening methods. The mCIM is a useful tool for microbiology laboratories due to its simplicity, clear criteria, cost-effectiveness and availability at any laboratory.

Nosocomial spread of Klebsiella pneumoniae isolates producing blaGES-4 carbapenemase at a Japanese hospital.

Six Klebsiella pneumoniae clinical isolates resistant to various cephalosporins and cephamycins were identified in a Japanese general hospital, a tertiary care hospital, between November 2009 and April 2010. All K. pneumoniae isolates carried blaGES-4 and blaSHV-1, while 2 K. pneumoniae isolates also harbored blaCTX-M-15. The pulsed-field gel electrophoresis patterns revealed that these 6 K. pneumoniae isolates were almost identical, suggesting their clonal relatedness. Plasmid profiles and conjugation assays revealed that these blaGES-4 genes were located on similar conjugative plasmids. These data indicate that nosocomial spread caused by K. pneumoniae isolates producing blaGES-4 carbapenemase occurred at a Japanese general hospital. K. pneumoniae isolate harboring blaGES-4 is rarely reported in Japan, and, to the best of our knowledge, this is the second report of K. pneumoniae isolates harboring blaGES-4 that occurred nosocomial spread in Japan.

[Mycotic Aneurysm by Saccharomyces cerevisiae-accompanying Ascending Aortic Graft Infection: A Case Report].

We treated an extremely rare case of a mycotic aneurysm with infection of an artificial blood vessel by Saccharomyces cerevisiae, which was the first case in Japan. The patient was an 84-year-old woman. Five months before hospitalization, replacement of the ascending aorta was performed for a dissecting aneurysm of the ascending aorta. On regular follow-up examination, she had no symptoms, but accumulation of a liquid was detected around the artificial blood vessel on computed tomography (CT) imaging. She was immediately hospitalized. An emergency operation was performed because of the infected aneurysm, which accompanied infection of the artificial blood vessel. We could not detect any microorganisms in the blood or tissue culture, but we made a diagnosis of S. cerevisiae infection after performing broad-range polymerase chain reaction (PCR), followed by deoxyribonucleic acid (DNA) sequencing analysis. When an infected aneurysm is suspected after imaging analysis, such as CT, in a patient without fever or chest pain and with poor inflammatory reactions, an infected aneurysm caused by a fungus should be considered, even though blood or tissue culture results are negative. It is important to perform histopathological examination using Grocott silver stain and genetic testing (broad-range PCR and DNA sequencing analysis) of the tissue to identify the fungal infection. In the elderly, the number of cases of infection with S. cerevisiae may increase, and these cases may require more attention in the near future.

[Penile Tuberculosis : A Case Report].

A 66-year-old man presented with a chief complaint of glans penis pain, induration, and discharge of pus. He was prescribed a course of antibiotics, but the condition persisted despite treatment. Thus, we differrentially diagnosed the patient with penile tuberculosis and pyoderma gangrenosum, and performed a biopsy of the penis. The biopsy result was thickening of the horny layer epidermis with only a foreign body granuloma composed of inflammatory cells, and did not lead to a definitive diagnosis. Thoraca-abdominal computed tomography revealed axillary lymphadenopathy with necrosis. Suspecting tuberculosis lymphadenitis, we performed T-spot and QuantiFERONtests. The result was T-spot negative and QuantiFERONpositive, so we diagnosed the patient with penile tuberculosis, and started antituberculosis medication. In about half a year after the start of treatment the symptoms subsided, and lymphadenopathy showed reduction.

Susceptibility of various oral antibacterial agents against extended spectrum ß-lactamase producing Escherichia coli and Klebsiella pneumoniae.

With the increase in extended spectrum ß-lactamase (ESBL)-producing bacteria in the community, cases are often seen in which treatment of infectious diseases with oral antimicrobial agents is difficult. Therefore, we measured the antimicrobial activities of 14 currently available oral antimicrobial agents against ESBL-producing Escherichia coli and Klebsiella pneumoniae. Based on the standard of the Clinical and Laboratory Standards Institute (CLSI), E. coli showed high susceptibility rates of 99.4% to faropenem (FRPM). In terms of fluoroquinolones, the susceptibility rate of E. coli to levofloxacin (LVFX) was low at 32.2%, whereas it showed a good susceptibility rate of 93.1% to sitafloxacin (STFX). With respect to other antimicrobial agents, susceptibility rates to fosfomycin (FOM) and colistin (CL) were more than 90% each, whereas rates of the two antimicrobial agents expected as therapeutic agents, minocycline (MINO) and sulfamethoxazole-trimethoprim (ST), were low at 62.4% and 44.3%, respectively. Based on the CLSI standard, K. pneumoniae showed high susceptibility rates to ceftibuten (CETB) (91.89%), LVFX (86.49%), and STFX (94.6%), indicating that K. pneumoniae showed higher rates than those of E. coli, particularly to fluoroquinolones. Comparison of susceptibility rates according to E. coli genotype showed that many antimicrobial agents existed to which the CTX-M-9 group showed high susceptibility rates. However, there were many agents to which the CTX-M-1 group showed low susceptibility rates, particularly to CETB (51.1%) and LVFX (17.0%). Although there was no significant difference by genotype between FRPM, STFX, and FOM, a significant difference was observed between LVFX, MINO, and ST. Antibiotic-resistant bacteria with highly pathogenic strains have spread in the community, appropriate use of oral antimicrobial agents is required.

Genomic epidemiology and temperature dependency of hypermucoviscous Klebsiella pneumoniae in Japan.

Klebsiella pneumoniae (Kp) has emerged as a global life-threatening pathogen owing to its multidrug resistance and hypervirulence phenotype. Several fatal outbreaks of carbapenem-resistant hypervirulent Kp have been reported recently. Hypermucoviscosity (HMV) is a phenotype commonly associated with hypervirulence of Kp, which is usually regulated by rmpA or rmpA2 (regulators of the mucoid phenotype). Here, we found that temperature was important in the HMV phenotype of Kp, and the impact of temperature on HMV was not uniform among strains. We investigated the HMV phenotype at 37 °C and room temperature (20-25 °C) in 170 clinically isolated hypermucoviscous Kp strains in Japan and analysed the association between the HMV phenotype, virulence genes and antimicrobial resistance (AMR) genes. String length distribution at different temperatures was correlated with the genomic population of Kp. The strains carrying rmpA/rmpA2 frequently showed the HMV phenotype at 37 °C, while the strains negative for these genes tended to show the HMV phenotype at room temperature. Hypervirulent Kp clusters carrying rmpA/rmpA2 without extended-spectrum beta-lactamases (ESBL)/carbapenemases produced higher string lengths at 37 °C than at room temperature, and were mostly isolated from the respiratory tract. Other HMV strains showed distinct characteristics of not carrying rmpA/rmpA2 but were positive for ESBL/carbapenemases, with a higher string length at room temperature than at 37 °C, and were frequently isolated from bloodstream infections. In total, 21 (13.5 %) HMV isolates carried ESBL and carbapenemases, among which five isolates were carbapenem-resistant hypervirulent Kp with a pLVPK-like plasmid (an epidemic virulence plasmid) and a pKPI-6-like plasmid (an epidemic blaIMP-6-bearing plasmid in Japan), suggesting the convergence of worldwide hypervirulence and epidemic AMR in Japan.

Successful Treatment of Intestinal Mycosis Caused by a Simultaneous Infection with Lichtheimia ramosa and Aspergillus calidoustus.

A 53-year-old woman was hospitalized due to septic shock after developing pneumococcal pneumonia after undergoing esophageal cancer surgery. Her transverse colon became perforated after receiving antimicrobial chemotherapy; therefore, emergency subtotal colectomy was performed. Fungi detected in both her colon tissue and a drainage sample indicated intestinal mucormycosis. Early intensive treatment with high-dose liposomal amphotericin B was successful, and she was subsequently discharged from the hospital. The fungal isolates were identified to be Lichtheimia ramosa and Aspergillus calidoustus via gene sequencing using panfungal primers as well as species-specific primers against elongation factor 1 and beta-tubulin for detecting Lichtheimia and Aspergillus, respectively.

[Pyogenic spondylitis by Enterobacter cloacae as a postoperative complication of TURP: a case report].

We report a case of pyogenic spondylitis caused by Enterobacter cloacae as a rare complication of transurethral resection of the prostate (TURP). A 79-year-old man underwent TURP. Immediate after removal of urethral catheter on postoperative day (POD) 7, he developed high fever > 40 degrees C with increased acute inflammatory reaction. Urine and blood culture detected E. cloacae and methicillin-resistant Staplylococcus aureus. He complained of lumbago since POD 9. Two-week administration of imipenem and teicoplanin resulted in resolution of fever as well as laboratory data, so intravenous antibiotics were changed to oral gatifloxacin. However, his lumbago worsened and gait disturbance appeared. On POD 39, diagnosis of pyogenic spondylitis was finally obtained by Ga-scintigraphy and magnetic resonance imaging. Aspiration of the intervertebral disk (L4-5) revealed E. cloacae as the causative organism of pyogenic spondylitis. His condition improved after conservative treatment with teicoplanin, meropenem and ciplofloxacin for 9 weeks.

[Extended voriconazole theraphy and long term survival of a patient with invasive central aspergillosis causing stroke].

Central nervous system (CNS) aspergillosis with stroke has a high mortality and poor prognosis generally. We report a 78-years-old woman with diabetes mellitus, who developed invasive paranasal sinus aspergillosis with the orbital apex syndrome on the right side and cerebral infarction caused by intracranial occlusion of the right internal carotid artery. Based on the presence of a mass lesion in the ethmoid sinus extending to the orbital apex on the right side with cranial CT, the mass lesion was surgically removed and the pathological examination of the surgical specimen revealed aspergillus mold. Immediately after surgery, we initiated treatment with voriconazole 200 mg × 2/day intravenously for 38 days, and then via feeding tube for 86 days until the galactomannan-aspergillus antigen level in the cerebrospinal fluid became negative at 132 days. She is alive now for almost two years without relapse of aspergillosis. There is no definitive guideline for management of patients with CNS aspergillosis concerning the length of drug treatment and the method for monitoring the response for treatment. We believe that measurement of the galactomannan-aspergillus antigen level in the cerebrospinal fluid might be a useful way of monitoring the efficacy of treatment for CNS aspergillosis.