Prevalence of ESBL-producing Escherichia coli and carbapenem-resistant Enterobacteriaceae in treated wastewater: a comparison with nosocomial infection surveillance.

The increasing prevalence of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli and carbapenem-resistant Enterobacteriaceae (CRE) is a worldwide health threat. Monitoring of these resistant bacteria in the environment can provide regional prevalence reflecting both healthy and infected populations, although the quantitative monitoring of those resistant bacteria, especially CRE, is difficult due to their low proportion in the total Enterobacteriaceae population and the possible interference by autochthonous species with intrinsic resistance. In this study, these resistant bacteria in treated wastewater were quantified at 12 different treatment plants. The proportions of cefotaxime-resistant and ESBL-producing E. coli in the total E. coli population in the chlorinated effluents in Tokyo were 5.7 and 5.3%, respectively. The estimated proportion of CRE was 0.007% with the constituting species of Klebsiella spp. and Enterobacter spp., although the conditions during the first incubation may have affected the estimation even after the correction by the proportion of resistant population in the isolates. The observed resistant proportions in this study were lower than those in the surveillance on nosocomial infection not only for inpatients but also for outpatients, and higher than those in the veterinary monitoring.

Antimicrobial susceptibility testing of rapidly growing mycobacteria isolated in Japan.

BACKGROUND: Difficult-to-treat infections caused by rapidly growing mycobacteria (RGM) are increasingly observed in clinical settings. However, studies on antimicrobial susceptibilities and effective treatments against RGM in Japan are limited. METHODS: We conducted susceptibility testing of potential antimicrobial agents, including tigecycline and tebipenem, against RGM. Clinical RGM isolates were collected from a university hospital in Japan between December 2010 and August 2013. They were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and the sequencing of 16S rRNA, rpoB, and hsp65 genes. The samples were utilized for susceptibility testing using 16 antimicrobials, with frozen broth microdilution panels. RESULTS: Forty-two isolates were obtained: 13, Mycobacterium abscessus complex; 12, Mycobacterium chelonae; 9, Mycobacterium fortuitum; and 8, M. fortuitum group species other than M. fortuitum. Different antimicrobial susceptibility patterns were observed between RGM species. Clarithromycin-susceptible strain rates were determined to be 0, 62, and 100% for M. fortuitum, M. abscessus complex, and M. chelonae, respectively. M. abscessus complex (100%) and >80% M. chelonae isolates were non-susceptible, while 100% M. fortuitum group isolates were susceptible to moxifloxacin. Linezolid showed good activity against 77% M. abscessus complex, 89% M. fortuitum, and 100% M. chelonae isolates. Regardless of species, all tested isolates were inhibited by tigecycline at very low minimal inhibitory concentrations (MICs) of ≤0.5 µg/mL. MICs of tebipenem, an oral carbapenem, were ≤4 µg/mL against all M. fortuitum group isolates. CONCLUSIONS: Our study demonstrates the importance of correct identification and antimicrobial susceptibility testing, including the testing of potential new agents, in the management of RGM infections.

Clinical characteristics and antimicrobial susceptibility of Bacillus cereus blood stream infections.

BACKGROUND: Bacillus cereus is one of the pathogens causing nosocomial bloodstream infections (BSIs). However, few reports have documented the antimicrobial susceptibility and clinical characteristics of Bacillus cereus BSI and the importance of empirical therapy. The aim of this study was to investigate the clinical characteristics and antimicrobial susceptibility of B. cereus isolates from patients with BSI and to analyze the impact of appropriate empirical therapy on the outcome of patients with B. cereus BSI. METHODS: All adult cases of bacteremia between April 2003 and March 2012 in a teaching hospital in Tokyo, Japan were reviewed retrospectively. Clinical data were collected from the patients' medical records and charts. Antimicrobial susceptibility testing was performed by broth microdilution method. The patients with B. cereus BSI were divided into an appropriate empirical therapy group and an inappropriate empirical therapy group. The primary outcome was all-cause mortality at 4 weeks after the start of BSI. The secondary outcome was early defervescence within 2 days after starting empirical therapy. RESULTS: There were 29 B. cereus bloodstream infection cases. No vancomycin, gentamicin, and imipenem-resistant isolates were found. However, 65.5 % were resistant to clindamycin and 10.3 % were resistant to levofloxacin. The main etiology was venous catheter-related (69 %). All-cause mortality at 4 weeks was not significantly different between the appropriate empirical therapy group (9 cases) and the inappropriate group (20 cases) in this study. However, early defervescence within 2 days after starting empirical therapy was significantly different (p = 0.032). CONCLUSIONS: The BSI of B. cereus is mostly caused by venous catheter-related infections. Appropriate empirical therapy is important to achieve early clinical resolution in B. cereus BSI. Vancomycin is one of the appropriate selections of empirical therapy for B. cereus BSI.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2010: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, was conducted by Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases and Japanese Society for Clinical Microbiology in 2010. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period from January and April 2010 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical and Laboratory Standard Institutes using maximum 45 antibacterial agents. Susceptibility testing was evaluable with 954 strains (206 Staphylococcus aureus, 189 Streptococcus pneumoniae, 4 Streptococcus pyogenes, 182 Haemophilus influenzae, 74 Moraxella catarrhalis, 139 Klebsiella pneumoniae and 160 Pseudomonas aeruginosa). Ratio of methicillin-resistant S. aureus was as high as 50.5%, and those of penicillin-intermediate and -resistant S. pneumoniae were 1.1% and 0.0%, respectively. Among H. influenzae, 17.6% of them were found to be ß-lactamase-non-producing ampicillin (ABPC)-intermediately resistant, 33.5% to be ß-lactamase-non-producing ABPC-resistant and 11.0% to be ß-lactamase-producing ABPC-resistant strains. Extended spectrum ß-lactamase-producing K. pneumoniae and multi-drug resistant P. aeruginosa with metallo ß-lactamase were 2.9% and 0.6%, respectively. Continuous national surveillance of antimicrobial susceptibility of respiratory pathogens is crucial in order to monitor changing patterns of susceptibility and to be able to update treatment recommendations on a regular basis.

[Effects of the new comprehensive system for designating illegal drug components on the abuse of designer drugs and future problems based on an online questionnaire].

Recently, the abuse of designer drugs has become a social problem. Designer drugs are created by modifying part of the chemical structure of drugs that have already been categorized as illegal, thereby creating a different chemical compound in order to evade Pharmaceutical Affairs Law regulations. The new comprehensive system for designating illegal drug components has been in effect since March 2013, and many designer drugs can now be regulated. We conducted an online questionnaire survey of people with a history of designer drug use to elucidate the effects of the new system on the abuse of designer drugs and to identify potential future problems. Over half the subjects obtained designer drugs only before the new system was implemented. Awareness of the system was significantly lower among subjects who obtained designer drugs for the first time after its introduction than those who obtained the drugs only before its implementation. Due to the new system, all methods of acquiring designer drugs saw decreases in activity. However, the ratio of the acquisition of designer drugs via the Internet increased. Since over 50% of the subjects never obtained designer drugs after the new system was introduced, goals that aimed to make drug procurement more difficult were achieved. However, awareness of the new system among subjects who obtained designer drugs after the new system was introduced was significantly low. Therefore, fostering greater public awareness of the new system is necessary. The results of the questionnaire also suggested that acquiring designer drugs through the Internet has hardly been affected by the new system. We strongly hope that there will be a greater push to restrict the sale of designer drugs on the Internet in the near future.

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (2006)].

From October 2006 to September 2007, we collected the specimen from 356 patients with lower respiratory tract infections in 14 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and patients' characteristics. Of 414 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in infection, 407 strains were examined. The isolated bacteria were: Staphylococcus aureus 64, Streptococcus pneumoniae 96, Haemophilus influenzae 87, Pseudomonas aeruginosa (non-mucoid) 52, P. aeruginosa (mucoid) 11, Klebsiella pneumoniae 20, and Moraxella catarrhalis 44. Of 64 S. aureus strains, those with 2 microg/ml or less of MIC of oxacillin (methicillin-susceptible S. aureus: MSSA) and those with 4 microg/ml or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) were 27 (42.2%) and 37 (57.8%) strains, respectively. Against MSSA, imipenem had the most potent antibacterial activity and inhibited the growth of all strains at 0.063 microg/ml or less. Against MRSA, vancomycin and linezolid showed the most potent activity and inhibited the growth of all the strains at 1 microg/ml. Carbapenems showed the most potent activities against S. pneumoniae and in particular, panipenem inhibited the growth of all the strains at 0.063 microg/ml or less. Imipenem and faropenem also had a preferable activity and inhibited the growth of all the strains at 0.125 and 0.5 microg/ml, respectively. In contrast, there were high-resistant strains (MIC: over 128 microg/ml) for erythromycin (45.8%) and clindamycin (20.8%). Against H. influenzae, levofloxacin showed the most potent activity and its MIC90 was 0.063 microg/ml or less. Meropenem showed the most potent activity against P. aeruginosa (mucoid) and its MIC90 was 0.5 microg/ml. Against P. aeruginosa (non-mucoid), tobramycin had the most potent activity and its MIC90 was 2 microg/ml. Against K. pneumoniae, cefozopran was the most potent activity and inhibited the growth of all the strains at 0.063 microg/ml or less. Also, all the antibacterial agents except ampicillin generally showed a potent activity against M. catarrhalis and the MIC90 of them were 2 microg/ml or less. The approximately half the number (50.6%) of the patients with respiratory infection were aged 70 years or older. Bacterial pneumonia and chronic bronchitis accounted for 49.2% and 28.1% of all the respiratory infections, respectively. The bacteria frequently isolated from the patients with bacterial pneumonia were S. pneumoniae (29.2%), S. aureus (20.8%), and H. influenzae (12.9%). H. influenzae (25.0%) and P. aeruginosa (21.7%) also were frequently isolated from the patients with chronic bronchitis. Before the antibacterial agent administration, the bacteria frequently isolated from the patients were S. pneumoniae (27.5%) and H. influenzae (22.5%). The bacteria frequently isolated from the patients treated with macrolides was P. aeruginosa, and its isolation frequently was 39.4%.

Molecular and microbiological characterization of Clostridium difficile isolates from single, relapse, and reinfection cases.

In this study, we investigated the correlation between the microbiological characteristics of Clostridium difficile clinical isolates and the recurrence of C. difficile-associated disease (CDAD). Twenty C. difficile isolates recovered from 20 single infection cases and 53 isolates from 20 recurrent cases were analyzed by pulsed-field gel electrophoresis (PFGE) and PCR ribotyping, and the cytotoxicity, antimicrobial susceptibility, and sporulation/germination rates of the isolates were examined. Recurrent cases were divided into relapse or reinfection cases by the results of C. difficile DNA typing. Among the 20 recurrent cases, 16 cases (80%) were identified to be relapse cases caused by the initial strain and the remaining 4 cases (20%) were identified to be reinfection cases caused by different strains. All 73 isolates were susceptible to both vancomycin and metronidazole, but resistance against clindamycin, ceftriaxone, erythromycin, and ciprofloxacin was found in 87.7%, 93.2%, 87.7%, and 100% of the isolates, respectively. No correlations between DNA typing group, cytotoxicity, and sporulation rate of isolates and infection status, i.e., single, relapse, or reinfection, were observed. However, the isolates recovered from relapse cases showed a significantly higher germination rate when incubated in medium lacking the germination stimulant sodium taurocholate. These results indicate that the germination ability of C. difficile may be a potential risk factor for the recurrence of CDAD.

Nationwide surveillance of bacterial respiratory pathogens conducted by the Surveillance Committee of Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Clinical Microbiology in 2009: general view of the pathogens' antibacterial susceptibility.

For the purpose of nationwide surveillance of antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, the Japanese Society of Chemotherapy (JSC) started a survey in 2006. From 2009, JSC continued the survey in collaboration with the Japanese Association for Infectious Diseases and the Japanese Society for Clinical Microbiology. The fourth-year survey was conducted during the period from January and April 2009 by the three societies. A total of 684 strains were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections. Susceptibility testing was evaluable with 635 strains (130 Staphylococcus aureus, 127 Streptococcus pneumoniae, 4 Streptococcus pyogenes, 123 Haemophilus influenzae, 70 Moraxella catarrhalis, 78 Klebsiella pneumoniae, and 103 Pseudomonas aeruginosa). A maximum of 45 antibacterial agents including 26 ß-lactams (four penicillins, three penicillins in combination with ß-lactamase inhibitors, four oral cephems, eight parenteral cephems, one monobactam, five carbapenems, and one penem), four aminoglycosides, four macrolides (including ketolide), one lincosamide, one tetracycline, two glycopeptides, six fluoroquinolones, and one oxazolidinone were used for the study. Analysis was conducted at the central reference laboratory according to the method recommended by the Clinical and Laboratory Standard Institute (CLSI). Incidence of methicillin-resistant S. aureus (MRSA) was as high as 58.5 %, and that of penicillin-intermediate and penicillin-resistant S. pneumoniae (PISP and PRSP) was 6.3 % and 0.0 %, respectively. Among H. influenzae, 21.1 % of them were found to be ß-lactamase-non-producing ampicillin (ABPC)-intermediately resistant (BLNAI), 18.7 % to be ß-lactamase-non-producing ABPC-resistant (BLNAR), and 5.7 % to be ß-lactamase-producing ABPC-resistant (BLPAR) strains. A high frequency (76.5 %) of ß-lactamase-producing strains has been suspected in Moraxella catarrhalis isolates. Four (3.2 %) extended-spectrum ß-lactamase-producing K. pneumoniae were found among 126 strains. Four isolates (2.5 %) of P. aeruginosa were found to be metallo-ß-lactamase-producing strains, including three (1.9 %) suspected multi-drug resistant strains showing resistance against imipenem, amikacin, and ciprofloxacin. Continuous national surveillance of the antimicrobial susceptibility of respiratory pathogens is crucial to monitor changing patterns of susceptibility and to be able to update treatment recommendations on a regular basis.

[Infection control team (ICT) in cooperation with microbiology laboratories].

Infection control as a medical safety measure is an important issue in all medical facilities. In order to tackle this measure, cooperation between the infection control team (ICT) and microbiological laboratory is indispensable. Multiple drug-resistant bacteria have shifted from Gram-positive bacteria to Gram-negative bacilli within the last ten years. There are also a variety of bacilli, complicating the examination method and test results further. Therefore, cooperation between the ICT and microbiological laboratory has become important to understand examination results and to use them. In order to maintain functional cooperation, explanatory and communicative ability between the microbiological laboratory and ICT is required every day. Such positive information exchange will develop into efficient and functional ICT activity.

Nationwide surveillance of bacterial respiratory pathogens conducted by the Japanese Society of Chemotherapy in 2008: general view of the pathogens' antibacterial susceptibility.

For the purpose of nationwide surveillance of the antimicrobial susceptibility of bacterial respiratory pathogens collected from patients in Japan, the Japanese Society of Chemotherapy conducted a third year of nationwide surveillance during the period from January to April 2008. A total of 1,097 strains were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections. Susceptibility testing was evaluable with 987 strains (189 Staphylococcus aureus, 211 Streptococcus pneumoniae, 6 Streptococcus pyogenes, 187 Haemophilus influenzae, 106 Moraxella catarrhalis, 126 Klebsiella pneumoniae, and 162 Pseudomonas aeruginosa). A total of 44 antibacterial agents, including 26 ß-lactams (four penicillins, three penicillins in combination with ß-lactamase inhibitors, four oral cephems, eight parenteral cephems, one monobactam, five carbapenems, and one penem), three aminoglycosides, four macrolides (including a ketolide), one lincosamide, one tetracycline, two glycopeptides, six fluoroquinolones, and one oxazolidinone were used for the study. Analysis was conducted at the central reference laboratory according to the method recommended by the Clinical and Laboratory Standard Institute (CLSI). The incidence of methicillin-resistant S. aureus (MRSA) was as high as 59.8%, and those of penicillin-intermediate and penicillin-resistant S. pneumoniae (PISP and PRSP) were 35.5 and 11.8%, respectively. Among H. influenzae, 13.9% of them were found to be ß-lactamase-non-producing ampicillin (ABPC)-intermediately resistant (BLNAI), 26.7% to be ß-lactamase-non-producing ABPC-resistant (BLNAR), and 5.3% to be ß-lactamase-producing ABPC-resistant (BLPAR) strains. A high frequency (76.5%) of ß-lactamase-producing strains was suspected in Moraxella catarrhalis isolates. Four (3.2%) extended-spectrum ß-lactamase-producing K. pneumoniae were found among 126 strains. Four isolates (2.5%) of P. aeruginosa were found to be metallo ß-lactamase-producing strains, including three (1.9%) suspected multidrug-resistant strains showing resistance to imipenem, amikacin, and ciprofloxacin. Continual national surveillance of the antimicrobial susceptibility of respiratory pathogens is crucial in order to monitor changing patterns of susceptibility and to be able to update treatment recommendations on a regular basis.

[Severe primary liver abscess and septic pulmonary embolism due to Klebsiella pneumoniae with hypermucoviscosity phenotype].

A 70-year-old man with diabetes mellitus seen for fever, right chest pain, and right-lung field consolidation on chest X-ray was found in thoracoabdominal computed tomography (CT) to have variable-sized nodules in both lung fields and multiple low-density hepatic areas. On physical examination, his pulse was 145 beats per minute and blood pressure 92/68mmHg, indicating a preshock state. Laboratory tests showed elevated WBC of 15,200/microL, serum-C-reactive protein (CRP) of 34.4 mg/dL, and a decreased platelet count of 16,000/microL. Suspecting liver abscesses complicated by a septic pulmonary embolism, we immediately conducted percutaneous transhepatic abscess drainage (PTAD). Liver abscess blood culture and drainage fluid grew the Klebsiella pneumoniae hypermucoviscosity phenotype, carrying the rmpA gene. Although the man had been in critical condition on admission, broad-spectrum antibiotics and PTAD treatment improved his clinical condition to where he could be discharged without problem.

Patient satisfaction with oral health check-ups at a community pharmacy and their effect on oral self-care habits and dental consultation behavior.

Maintaining good oral health is important because oral diseases are related to systemic diseases, and community pharmacies play a key role in maintaining the health of local residents. This study aimed to examine the effects of oral health check-ups and information provision at community pharmacies on oral health-associated behaviors as well as patient satisfaction. We conducted oral health check-ups and provided information about oral health self-care to 84 patients at a community pharmacy, and then asked them to complete a questionnaire survey. One month later, we sent them a follow-up questionnaire and received responses from 66.7% (56/84) of the participants. The large majority were satisfied with the salivary test (95.2%) and the information (96.4%) we provided. Most of the participants (89.3%) indicated that they wanted to use the oral health check-up service again in the future. Compared with baseline, the ratio of participants restricting their intake of sugar-rich foods and drinks significantly increased 1 month later (p = 0.021). About 60% of those who had not undergone a regular dental examination at baseline reported newly visiting or planning to visit a dental clinic. The results revealed high satisfaction with the oral health check-up and information about oral self-care they received at the community pharmacy. The results suggested that oral health check-ups had the potential to change both oral self-care habits and dental consultation behavior. Our findings indicate that community pharmacies can contribute to the maintenance and promotion of oral health by providing oral health check-ups to local residents.

Evaluation of pathogenicity and therapeutic effectiveness of antibiotics using silkworm Nocardia infection model.

Nocardia is a ubiquitous environmental microbe that causes nocardiosis against immunosuppressed and immunocompromised hosts. The assay system for the quantitative evaluation of virulence of Nocardia sp. or therapeutic effectiveness of antimicrobials for treatment of nocardiosis is not established so far. In this study, we established an infection model of Nocardia sp. using silkworm as an alternative animal model. We found that all tested Nocardia sp. such as Nocardia asiatica, Nocardia elegans, Nocardia exalbida, Nocardia farcinica, and Nocardia nova killed silkworm and their killing ability were different by species. N. farcinica showed higher pathogenicity among tested strain, similar to the mouse model as previously reported. In addition, we found that antimicrobials such as amikacin and minocycline showed therapeutic effectiveness in silkworms infected with N. farcinica, and we could determine effective doses 50 (ED50) values. These results suggest that silkworm is a useful alternative animal to evaluate the pathogenicity of Nocardia pathogen and the therapeutic effects of antimicrobials against Nocardia sp. in a quantitative manner.

[Susceptibility surveillance of clinical isolates to fluoroquinolone antimicrobial agents from 2003 to 2008: post-marketing study of prulifloxacin].

Yearly changes in the susceptibility of clinical isolates to ulifloxacin (UFX) and other fluoroquinolones were examined through surveys over 3 periods. In the first survey, 534 strains derived from 19 species were collected from clinical specimens during 6 months from December 2003 to May 2004. In the same way, 805 strains were collected from December 2005 to May 2006 in the second survey, and 863 strains were from December 2007 to May 2008 in the third survey. Over these 3 study periods, the susceptibilities of fluoroquinolones against methicillin-susceptible Staphylococcus aureus and Escherichia coli were decreased. The isolation frequency of levofloxacin-nonsusceptible strain was increased from 0% to 11.8% and from 14.6% to 20.8%, respectively. MIC90s of UFX against these pathogens were also increased, but its MIC90 for E. coli was 2 to 4 times lower than that of levofloxacin. On the other hand, the susceptibility of strains of Klebsiella pneumoniae to UFX was increased. Among the fluoroquinolones tested, UFX showed the most potent activity against Pseudomonas aeruginosa, and no changes in the MIC90s occurred during the surveillance. Although one strain of Streptococcus pneumoniae isolated in the third study period showed levofloxacin-resistance (MIC, 8 microg/mL), there were nearly no changes in the MIC90s of any agents tested including UFX against S. pneumoniae during the surveillance. As for other bacterial species, a tendency to increase in resistance to UFX was not observed. The activity of UFX against Salmonella spp. and Shigella spp. was superior/equal to those of fluoroquinolones tested.

Unusual sonographic appearance of synovial sarcoma of the anterior abdominal wall.

We report a case of synovial sarcoma in a 58-year-old woman arising from the anterior abdominal wall. Sonography demonstrated a large mass with an unusual complex "honeycomb" echotexture. Doppler imaging displayed increased vascularity in the solid parts of the tumor.

KHM-1, a novel plasmid-mediated metallo-beta-lactamase from a Citrobacter freundii clinical isolate.

A novel gene, bla(KHM-1), encoding a metallo-beta-lactamase, KHM-1, was cloned from a clinical isolate of Citrobacter freundii resistant to most beta-lactam antibiotics. Escherichia coli expressing bla(KHM-1) was resistant to all broad-spectrum beta-lactams except for monobactams and showed reduced susceptibility to carbapenems. Recombinant KHM-1 exhibited EDTA-inhibitable hydrolytic activity against most beta-lactams, with an overall preference for cephalosporins.

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (2005)].

From October 2005 to September 2006, we collected the specimen from 366 patients with lower respiratory tract infections in 12 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and patients' characteristics. Of 411 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in infection, 406 strains were examined. The isolated bacteria were: Staphylococcus aureus 70, Streptococcus pneumoniae 85, Haemophilus influenzae 78, Pseudomonas aeruginosa (non-mucoid) 46, P. aeruginosa (mucoid) 14, Klebsiella pneumoniae 21, and Moraxella subgenus Branhamella catarrhalis 40. Of 70 S. aureus strains, those with 2 microg/ml or less of MIC of oxacillin (methicillin-susceptible S. aureus: MSSA) and those with 4 microg/ml or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) were 38 (54.3%) and 32 (45.7%) strains, respectively. Against MSSA, imipenem had the most potent antibacterial activity and inhibited the growth of 37 strains (97.4%) at 0.063 microg/ml or less. Against MRSA, arbekacin and vancomycin showed the most potent activity and inhibited the growth of all the strains at 1 microg/ml. Carbapenems showed the most potent activities against S. pneumoniae and in particular, panipenem inhibited the growth of all the strains at 0.063 microg/ml or less. Faropenem also had a preferable activity and inhibited the growth of all the strains at 0.25 microg/ml. In contrast, there were high-resistant strains (MIC: over 128 microg/ml) for erythromycin (38.1%) and clindamycin (22.6%). Against H. influenzae, levofloxacin showed the most potent activity and its MIC90 was 0.063 microg/ml or less. Meropenem showed the most potent activity against P. aeruginosa (mucoid) and its MIC90 was 0.5 microg/ml. Against P. aeruginosa (non-mucoid), arbekacin had the most potent activity and its MIC90 was 8 microg/ml. Against K. pneumoniae, cefozopran was the most potent activity and inhibited the growth of all the strains at 0.063 microg/ml or less. Also, all the antibacterial agents except ampicillin generally showed a potent activity against M. (B.) catarrhalis and the MIC90 of them were 2 microg/ml or less. The approximately half the number (53.6%) of the patients with respiratory infection were aged 70 years or older. Bacterial pneumonia and chronic bronchitis accounted for 44.3% and 29.8% of all the respiratory infection, respectively. The bacteria frequently isolated from the patients with bacterial pneumonia were S. aureus (15.4%), S. pneumoniae (23.4%), and H. influenzae (21.3%). S. aureus (25.4%) and S. pneumoniae (18.0%) also were frequently isolated from the patients with chronic bronchitis. Before the drug administration, the bacteria frequently isolated from the patients were S. pneumoniae (22.0%) and H. influenzae (21.4%). The bacteria frequently isolated from the patients treated with macrolides were S. pneumoniae and P. aeruginosa, and their isolation frequencies were each 35.3%.

Clinical and microbiological characteristics and occurrence of Klebsiella pneumoniae infection in Japan.

PURPOSE: Klebsiella pneumoniae is a pathogen that causes pneumonia and urinary tract infection. Hypervirulent K. pneumoniae strains often show hypermucoviscosity, are of the K1 or K2 serotype, and harbor the rmpA and magA genes. However, the differences in the prevalence of K. pneumoniae with these hypervirulent characteristics between the infection and colonization status are not well understood. Therefore, in this study, we compared the clinical and microbiological characteristics of K. pneumoniae isolated from urine or sputum samples of cases of infection and colonization. PATIENTS AND METHODS: This retrospective study was conducted at a tertiary care teaching hospital in Tokyo, Japan. Patients whose sputum or urine tested positive for the presence of K. pneumoniae isolates were randomly included in the study. Clinical and microbiological data were collected from medical records. RESULTS: Of the 130 cases investigated, 68 and 62 cases showed the presence of K. pneumoniae in the sputum and urine, respectively. There were 49 infection cases, including 21 in the sputum group and 28 in the urine group. The infections were not accompanied by liver abscess. Of the 130 K. pneumoniae isolates, 25 (19.2%) showed capsular serotype K1 or K2, whereas 33 (25.4%) showed hypermucoviscosity. The prevalence of virulence genes magA, allS, rmpA, mrkD, uge, kfu-BC, and wabG was 10% (all in K1), 13.1%, 16.9%, 85.4%, 79.2%, 36.9%, and 91.5%, respectively. In both the sputum and urine groups, there was no difference in the characteristics of patients with infection and those with colonization. Analysis of microbiological characteristics revealed that only rmpA was significantly more frequent in the infection cases than in the colonization/asymptomatic cases in both the sputum and urine groups. CONCLUSION: The rmpA-positive K. pneumoniae isolates were dominant in the infection cases compared with those in the colonization/asymptomatic cases, suggesting that rmpA may play a crucial role in the development of urinary tract infection and pneumonia.

Synergistic effects of vancomycin and ß-lactams against vancomycin highly resistant Staphylococcus aureus.

We previously reported isolating vancomycin (VAN) highly resistant Staphylococcus aureus (VRSA) strains from clinical methicillin-resistant S. aureus strains by repeating steps of in vitro mutagenesis and VAN selection. Here we describe that the in vitro susceptibility of these VRSA strains to VAN was markedly increased by combined treatment with ß-lactams such as ceftriaxone and oxacillin. Furthermore, in an in vivo silkworm infection model with VRSA, a combination of VAN and ceftriaxone exhibited therapeutic effects, whereas a combination of VAN and oxacillin did not. These findings suggest that combining VAN with an appropriate ß-lactam, such as ceftriaxone, is therapeutically effective against infectious diseases caused by VRSA.