Association between ratio of area under the concentration-time curve to minimum inhibitory concentration of vancomycin and clinical outcomes in Enterococcus faecium bacteremia.

The purpose of this study was to evaluate the relationship between the treatment resolution of Enterococcus faecium bacteremia and the pharmacodynamic targets of vancomycin. This is a retrospective single-center cohort study involving patients with E. faecium bacteremia on vancomycin therapy hospitalized between January 2010 and December 2021. The average vancomycin area under the concentration-time curve (AUC)0 -24 was computed using the Bayesian approach. The minimum inhibitory concentration (MIC) was determined using the broth microdilution method, and The AUC24/MIC value over the initial 24-48 h of therapy was calculated. We assessed 30-day mortality, as the primary outcome. Classification and regression tree analysis (CART) was used to identify the vancomycin AUC24/MIC target associated with 30-day mortality. Eighty-seven patients with E. faecium bacteremia were included in this study, with 14 (16.1%) being non-survivors. In the CART analysis, vancomycin AUC/MIC ≥414.3 was associated with a higher treatment success. In multivariate analysis, an AUC/MIC ≥414.3 was a significant factor for treatment success (adjusted odds ratio = 17.5, 95% confidence interval, 3.7-83.9). Our findings suggest that a target vancomycin AUC/MIC ≥414.3 is a good prognostic indicator and could be useful for treatment monitoring of E. faecium bacteremia.

Pre-Vaccination Anti-Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Seroprevalence in Workers at Three Japanese Hospitals.

BACKGROUND: Antibody testing is essential for accurately estimating the number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to investigate the influence of background factors on seroprevalence by testing for anti-SARS-CoV-2 antibodies in blood samples obtained from the staff of three hospitals. METHODS: This cross-sectional observational study was conducted from June 8 to July 4, 2020, as part of a mandatory health examination. Leftover blood samples collected during the health examinations at each hospital were used to test for the presence of anti-SARS-CoV-2 antibodies. The Elecsys Anti-SARS-CoV-2 RUO assay was used for antibody detection. The relationship between staff age, gender, body mass index, blood pressure, work environments with different exposure risks, place of residence, and campus location and seroprevalence was investigated. The data were anonymized prior to analysis. RESULTS: A total of 3,677 individuals were included in the study, comprising 2,554 females (69.5%) and 1,123 males (30.5%). Anti-SARS-CoV-2 antibody (immunoglobulin G) was detected in 13 participants (0.35%). Seroprevalence was slightly higher in males than females (0.62% vs. 0.23%, P=0.08). By occupation, anti-SARS-CoV-2 antibodies were found in 6 (0.75%) physicians, 6 (0.31%) nurses, and one individual (0.11%) in the medical personnel group, with slightly higher levels in physicians. No significant difference was noted in the seroprevalence in terms of all background factors. CONCLUSIONS: Our study shows that the background factors do not impact seropositivity rates. Thorough daily infection control and adherence to recommended health guidelines were found to reduce infection risk.

Evaluation of a carbapenem antimicrobial stewardship program and clinical outcomes in a Japanese hospital.

INTRODUCTION: Microorganisms can evolve and become resistant to antimicrobials, and this is known as antimicrobial resistance (AMR). Inappropriate use of antibiotics contributes to AMR, and antimicrobial stewardship programs have been developed to mitigate AMR. The Appropriate Use of Carbapenems Program was implemented in March 2019 in a university hospital and its effect was evaluated. METHODS: We conducted a prospective audit and feedback on carbapenems at the time of prescription daily. Additionally, we compared a monthly survey of the total days of therapy (DOTs) per 1000 patient-days for carbapenems, piperacillin/tazobactam, and fluoroquinolones. The susceptibility of Pseudomonas aeruginosa to meropenem, piperacillin/tazobactam, and levofloxacin was tested before (January 2018 to February 2019) and after (March 2019 to December 2020) the intervention. RESULTS: The monthly median DOTs of carbapenem usage decreased after the intervention; carbapenem use immediately declined during the intervention period. The monthly median DOTs of piperacillin/tazobactam and fluoroquinolones also decreased and continued to decline significantly after the intervention. Susceptibility of P. aeruginosa to meropenem, piperacillin/tazobactam, and levofloxacin did not change significantly during the study. CONCLUSION: The implementation of the Appropriate Use of Carbapenems Program was effective in reducing the use of broad-spectrum antibiotics and maintaining the antibiotic susceptibility of P. aeruginosa.

Clinical and Microbiological Features of Asymptomatic SARS-CoV-2 Infection and Mild COVID-19 in Seven Crewmembers of a Cruise Ship.

Objective To describe the clinical features and clinical course of individuals diagnosed with asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or mild coronavirus disease (COVID)-19. Patients The study participants consisted of 7 crewmembers of the passenger cruise-liner, Diamond Princess, who were admitted to our hospital after becoming infected with SARS-CoV-2 aboard the ship. Methods The data on patient background and biochemical test results were obtained from the patients' medical records. All patients had a chest X-ray, and a throat swab and sputum samples were sent for culture on admission. Results The median age of the 7 patients, of whom 4 were male and 3 were female, was 39 years (range: 23-47 years). On admission, none of them had fever, but 4 (57%) had a cough. None of them showed any signs of organ damage on laboratory testing. Chest X-ray showed pneumonia in one individual, which resolved spontaneously, while the other 6 had normal chest X-ray findings. Culture of throat swabs and sputum samples revealed that 4 patients (57%) had bacterial upper respiratory infections (Haemophilus influenzae, Klebsiella pneumoniae, and Staphylococcus aureus). The period from a positive polymerase chain reaction (PCR) test to negative conversion ranged from 5 to 13 days, with a median of 8 days. Conclusion Healthy young adults without risk factors who acquire SARS-CoV-2 infection may have an asymptomatic infection or may experience mild COVID-19. In addition to obesity, an older age, underlying illness, and being overweight can lead to a risk of exacerbation; thus, hospital management for such individuals may be desirable. Culturing respiratory samples may be useful for diagnosing secondary bacterial pneumonia.

Characterization of the IncFII-IncFIB(pB171) Plasmid Carrying bla NDM-5 in Escherichia coli ST405 Clinical Isolate in Japan.

PURPOSE: New Delhi metallo-ß-lactamase 5 (NDM-5) shows stronger resistance to carbapenems and broad-spectrum cephalosporins than NDM-1 because NDM-5 differs from NDM-1 by two amino acid substitutions. In this study, our aim was to characterize a NDM-5-producing Escherichia coli isolate KY1497 from a patient with urinary tract infection in Japan, who had no recent history of overseas travel. PATIENTS AND METHODS: NDM-5-producing E. coli isolate KY1497 was detected in the urine sample of a patient hospitalized in a tertiary hospital in Japan. The complete genome sequence of isolate KY1497 was determined by short- and long-read sequencing with hybrid assembly, followed by multilocus sequence typing (MLST), core-genome phylogeny analysis, plasmid analysis, and transconjugation experiments. RESULTS: KY1497 was classified as ST405 by MLST, and core-genome phylogeny exhibited the closest lineage to the clinical isolates in Nepal (IOMTU605) and Canada (FDAARGOS_448). KY1497 harbors bla NDM-5 in the IncFII-IncFIB(pB171) replicon plasmid (pKY1497_1, 123,767 base pairs). Plasmid analysis suggested that the cognate plasmids of pKY1497_1 have a minor plasmid background, rather than the globally disseminated IncX3 plasmid carrying bla NDM-5. Transconjugation analysis revealed that pKY1497_1 is transmissible to the recipient E. coli J53 strain. CONCLUSION: We characterized a novel Inc replicon plasmid (IncFII-IncFIB[pB171]) carrying bla NDM-5 and its host E. coli strain. NDMs are associated with a high risk of infection worldwide because of their antibiotic resistance and untreatable and hard-to-treat infections. Other patients in the hospital showed negative results for carbapenem-resistant Enterobacteriaceae. As NDM-producing strains are only sporadically detected in Japan, attention should be provided to the community prevalence of NDM-producing E. coli strains to prevent nosocomial infections.

Clinical usefulness of multiplex PCR-lateral flow for the diagnosis of orthopedic-related infections.

Objectives: Polymerase chain reaction (PCR)-based assays are being increasingly used for the diagnosis of orthopedic-related infections. Unfortunately, classical PCR requires imaging devices that are expensive and complex. We previously developed the PCR-lateral flow (PCR-LF) method, which does not require any additional imaging device. In the present study, the objective was to determine whether PCR-LF tests could be used to effectively diagnose orthopedic-related infections. Methods: In this study, we used PCR-LF to diagnose common causes of orthopedic-related infections and compared the results to those from conventional bacterial cultures of the same samples. Results: Notably, for 228 synovial fluid or pus specimens, the sensitivity and specificity of bacterial cultures were 53.5% and 97.7%, respectively, compared to 61.6% and 89.9% for PCR-LF. Although the difference in sensitivity between bacterial cultures and PCR-LF was not significant, when our analysis was limited to cases with suspected periprosthetic joint infection, the sensitivity of PCR-LF (66.1%) was superior to that of bacterial cultures (42.9%). Conclusion: This study indicates that PCR-LF is a useful method for diagnosing orthopedic-related infections.

Detection of Streptococcus agalactiae by immunochromatography with group B streptococcus-specific surface immunogenic protein in pregnant women.

BACKGROUND: Infection with Streptococcus agalactiae (Group B streptococcus: GBS) is a significant cause of morbidity and mortality in neonates. Screening for GBS is mainly done by culture-based methods, but a reliable result may take several days to obtain and culture is difficult to perform at institutions without a laboratory. We evaluated an immunochromatography method for rapid detection of GBS-specific surface immunogenic protein (Sip) using anti-Sip monoclonal antibodies. MATERIALS AND METHODS: A total of 377 cervical and vaginal swabs collected during weeks 35-37 of gestation were inoculated into GBS medium F and incubated. Growth of microorganisms and production of red/orange pigment were assessed by observation. Then culture extracts were subjected to immunochromatography and were also inoculated onto chromID Strepto B (STRB) medium, after which isolates were serotyped and characterized by PCR. RESULTS: Of the 377 samples, 54 (14.3%) were positive for GBS by immunochromatography after incubation in GBS medium F. On the other hand, GBS was isolated from 58 (15.4%) of the 377 samples by culture with GBS medium F and STRB medium. Ten of the 58 isolates were non-pigmented and 4 of these were not detected by immunochromatography. The sensitivity, specificity, positive predictive value, and negative predictive value of immunochromatography were 93.1% (54/58), 100% (319/319), 100% (54/54), and 98.8% (319/323), respectively. CONCLUSIONS: Immunochromatography was comparable to culture on STRB medium for detecting GBS, indicating that this method could be used clinically for GBS screening in pregnant women even at small institutions.

Evaluation of In Vitro Antiamoebic Activity of Antimicrobial Agents Against Clinical Acanthamoeba Isolates.

PURPOSE: The aim of this study was to elucidate in vitro antiamoebic activity of antimicrobial agents at short exposure times similar to those used for actual treatment against Acanthamoeba strains isolated from patients with keratitis. METHODS: The 5 clinical Acanthamoeba isolated in Japan were used in this study. Identification of genotypes for the Acanthamoeba isolates was performed using partial 18S ribosomal DNA (rDNA), including the ASA.S1 region sequences. Fluconazole, miconazole, itraconazole, voriconazole, amphotericin B, natamycin (pimaricin), and micafungin (antifungal agents), and chlorhexidine (a biguanide disinfectant), and sulfamethoxazole and paromomycin (antibacterial agents) were used to determine the antiamoebic activity against Acanthamoeba, which were determined by 50% and 90% growth inhibitory concentrations (IC50 and IC90) following exposing to each drug at 25°C for 7 days and 12 h. RESULTS: Among the tested antimicrobial agents, natamycin strongly inhibited the growth of all Acanthamoeba isolates at low concentration in both the 7-day (IC90 = 4.1 µg/mL) and 12-h (IC90 = 11.6 µg/mL) assays. Additionally, sulfamethoxazole exhibited strong antiamoebic activity (IC90 = 9.8 µg/mL) at low concentration in the 7-day assay. CONCLUSIONS: Our findings showed that natamycin ophthalmic solution might be an effective agent against Acanthamoeba keratitis. Additionally, frequent administration of sulfamethoxazole ophthalmic solution or systemic sulfamethoxazole-trimethoprim is also considered as an effective treatment for Acanthamoeba keratitis.

Modified Hodge test using Mueller-Hinton agar supplemented with cloxacillin improves screening for carbapenemase-producing clinical isolates of Enterobacteriaceae.

Increasing numbers of clinical isolates of Enterobacteriaceae that produce carbapenemase are now being detected, with the most common carbapenemase found among Enterobacteriaceae in Japan being IMP-1-type metallo-ß-lactamase. Clinical isolates of Enterobacteriaceae harbouring carbapenemases may be resistant to carbapenem antimicrobial agents, despite apparent in vitro susceptibility when tested according to Clinical and Laboratory Standards Institute criteria. We evaluated the prevalence of carbapenemase producers among isolates of Enterobacteriaceae at our hospital and assessed the performance of the modified Hodge test (MHT) for correctly identifying the phenotype. We studied 47 clinical isolates obtained between 2006 and 2010 for which the MIC of imipenem was 2 or 4 µg imipenem ml- 1. Antibacterial susceptibility testing was done for cephalosporins and carbapenems, the MHT was performed with meropenem and detection of the genes encoding IMP-1, VIM-2, KPC-2 and NDM-1-type metallo-ß-lactamases was performed by PCR. Twelve isolates showed a positive result in the MHT with meropenem and were classified as carbapenemase producers. Of these 12 isolates, seven carried the gene for IMP-1 type, but not for VIM-2, KPC-2 or NDM-1 types. None of the carbapenemase genes tested were detected in the other five isolates. All five isolates were Enterobacter cloacae showing high resistance to ceftazidime and aztreonam. False-positive results were inhibited when Mueller-Hinton agar supplemented with 200 mg cloxacillin ml- 1 was used for the MHT. Five of 12 MHT-positive isolates were shown to have no carbapenemase genes and these isolates were high AmpC producers. Adding cloxacillin when performing the MHT prevented such false-positive results. The MHT with cloxacillin can overcome most problems related to detection of carbapenemases.

A very rare case of primary meningococcal arthritis in an adult male.

We report here a very rare case of primary meningococcal arthritis of the knee joint without clinical features associated with meningococcemia, meningitis, or meningococcal complications. The patient suffered from diabetes mellitus and had experienced two episodes of joint trauma. Intravenous infusion of ampicillin/sulbactam for 18 consecutive days was successful.

[Clostridium tetani isolated from patients with systemic tetanus].

Clostridium tetani is widely distributed in ground or mud, especially in field and pond-shore surface layers. C. tetani is rarely isolated from specimens of patients with tetanus, and is generally diagnosed based on clinical symptoms such as trismus or general tonic spasms. This means that positive C. tetani infection is rarely diagnosed bacterially. Using gram straing, we identified C. tetani in specimens from patients suspected of C. tetani infection brought to the Kitasato University Hospital emergency center. Rapid gram staining information in the bacteriology laboratory is expected to improve recovery from C. tetani infection. It is therefore necessary to ensure clinical specimen quality control, and to keep standard strains of rare bacteria for isolation and identification.

[Emergence of linezolid-resistant Enterococcus faecalis strains from two inpatients in a pediatric ward].

We report herein on the isolation of three linezolid-resistant Enterococcus faecalis strains in 2011 from two pediatric inpatients at Kitasato University Hospital, Japan. Three linezolid resistant strains were isolated from two patients who shared the same room of a pediatric inpatient ward. Two linezolid resistant strains were isolated from patient A who had been treated with a total of 17,600mg of linezolid during 60 days of hospitalization (strains 1 and 2). The linezolid resistant E. faecalis persisted through the time that the patient had been discharged from the hospital. Another linezolid resistant strain was isolated from patient B who had no history of linezolid administration. The resistant strain in patient B phased out spontaneously. The minimum inhibitory concentration of linezolid in these strains ranged from 8.0 to 16.0 microg/mL. PCR amplification of the chromosomal gene encoding domain V of the 23S rRNA and subsequent nucleotide sequencing revealed that all the strains had at least one G2576T mutation. The pulse-field-gel electrophoretograms of the DNA treated with the SmaI restriction enzyme showed an identical profile suggesting that they were derived from a single resistant strain. These results suggested that the resistant strain occurred in patient A and was transmitted to patient B within the inpatient ward.

Clinical usefulness of multiplex PCR lateral flow in MRSA detection: a novel, rapid genetic testing method.

Methicillin-resistant Staphylococcus aureus (MRSA) with exogenous cassette DNA containing the methicillin-resistant gene mecA (SCCmec) poses a problem as a drug-resistant bacterium responsible for hospital- and community-acquired infections. The frequency of MRSA detection has recently been increasing rapidly in Japan, and SCCmec has also been classified more diversely into types I-V. A rapid test is essential for early diagnosis and treatment of MRSA infections, but detection by conventional methods requires at least two days. The newly developed multiplex PCR lateral flow method allows specific amplification of femA to detect S. aureus, mecA to detect SCCmec, and kdpC to detect SCCmec type II; moreover, PCR products can be evaluated visually in about 3 h. In the present study, we developed a PCR lateral flow method for MRSA using this method and investigated its clinical usefulness in the detection of MRSA. The results showed a diagnostic concordance rate of 91.7% for MRSA and methicillin-susceptible S. aureus between bacteriological examination and PCR lateral flow, and a high level of specificity in PCR lateral flow. In addition, a higher detection rate for S. aureus using the same sample was observed for PCR lateral flow (70.2%) than for bacteriological tests (48.6%). The above results show that PCR lateral flow for MRSA detection has high sensitivity, specificity, and speed, and its clinical application as a method for early diagnosis of MRSA infections appears to be feasible.

[The role of the genetic test of verotoxin for bacterial carrier investigation of cooking staff: detection of enterohemorrhagic Escherichia coli].

The Ministry of Health, Labour and Welfare revised the Manual for Hygiene Management at Large-scale Food Preparation Facilities (Shokuan; Issue No. 0618005) on June 18, 2008. This manual was issued for the purpose of food poisoning prevention in mass food service facilities based on the concept of hazard analysis and critical control point(HACCP). Especially this revision of the manual made verotoxin(VT examination indispensable in the practice of regular fecal examination for cooking staff (stool examination). Out of 150 fecal specimens that were examined on May 12, 2009, a specimen from a dietician revealed a strain of enterohemorrhagic Escherichia coli EHEC O103: H2 producing type I verotoxin (VT1). We studied the following with regard to EHEC O103: H2 producing VT1(EHEC O103): colony forms of the bacteria on the selective media for EHEC as well as the differential media for VT in use for stool examination in the laboratory and the usefulness of the hospital PCR based detection of VT genes. CHROMagar O26/O157 agar plates were used to select and isolate EHEC. Enterohemolysin blood agar plates were used to confirm VT. Polymerase chain reaction (PCR) was conducted using primers set EVT-1, 2 as well as EVS-1, 2. CHROMagar O26/O157 agar plates and enterohemolysin blood agar plates can distinguish EHEC strains easily, rapidly, and effectively, although not always correctly. The PCR method employs PCR technology targeting VT genes, so that it can verify VT genes in all strains of E. coli. This examination is useful for defining EHEC especially in stool examinations of asymptomatic patients. The PCR-based detection of VT genes was considered as a rational method for fecal examination compatible with the revised Manual for Hygiene Management at Large-scale Food Preparation Facilities.

[Annual changes in antimicrobial susceptibility of Campylobacter jejuni and Campylobacter coli isolated from acute diarrheic patients].

Two hundred thirty-one Campylobacter were isolated from acute diarrheic patients between January 2001 and December 2005. We evaluated annual changes in identified species of Campylobacter and their susceptibilities against antibiotics. Campylobacter jejuni (219 strains; 94.8%) and Campylobacter coli (12 strains; 5.2%) were identified to the species. Susceptibilities to four antimicrobial agents, minocycline (MINO), levofloxacin (LVFX), erythromycin (EM) and clindamycin (CLDM) were examined. The resistant rates of four antimicrobial agents in C. coli were significantly higher than that in C. jejuni. The susceptibility of C. jejuni to LVFX was variable, and MICs gave a bimodal distribution. The resistant rate against EM was estimated to be 9.2% in C. jejuni, 66.7% in C. coli. Moreover, young people ranging from 19 to 24 years old were predominant (47.7%) among the Campylobacter enteritis patients.

[Evaluation of antigen diagnostic kit in group A streptococcus mass infection].

We report a Food-borne group A streptococcus epidemic at Kitasato University campus on July 30 and 31, 2005, believed caused by lunch. A current mass group A streptococcus infection differing from the food-borne epidemic above occurred at Kitasato University East Hospital, also believed caused by lunch. Group A streptococcus was detected using a prompt diagnostic kit and bacterial culture from 116 clinical specimens taken from 116 patients with group A streptococcus pharyngitis at Kitasato University East Hospital on August 5, 2005. To investigate the utility of immunochromatographic detection of group A streptococcus antigen, 116 clinical specimens obtained from pharyngeal membranes by swab were examined using a prompt diagnostic kit for group A streptococcus (ImmunoCard STAT! STREP A TEST) and conventional bacterial culture. Group A streptococcus positivity differed between the two methods. Fourteen patients were found to be positive by the prompt diagnostic kit and 23 by bacterial culture. Four patients showing 1.0 x 10(6) cfu/mL estimated by the culture were difficult to diagnose with the prompt diagnostic kit,even though the detection sensitivity of this kit was 1.0 x 10(6) cfu/mL or more. Conventional bacterial culture should therefore be used in addition to the prompt diagnostic kit to detect group A streptococcus, especially in pharyngeal samples obtained from patients with pharyngitis.

[Nosocomial infection by multidrug-resistant Pseudomonas Aeruginosa (MDRP) presumably spread a radiation technician].

Isolated of multidrug resistance Pseudomonas aeruginosa (MDRP) that the receptivity pattern of the antimicrobial suscepti respectively resembled isolated from clinical specimens (sputum) in two patients of each internal medicine ward in Kitasato University East Hospital for two days from September 18 and 20, 2004. Both of bacteria were formed small colonies of a smooth-type on dollargalluskey improvement-type BTB agar plates, and the judgment of ClassB (metallo)-beta-lactamase by biochemical properties and disk diffusion method sodium mercaoto-acetic acid (SMA) was mutually corresponding. Moreover, it was same serotype C according to the serotype, and it was confirmed that it was the same bacterial strain from the molecular epidemiology analysis by Random amplified polymorphic DNA polymerase chain reaction (Random amplified polymorphic DNA polymerase chain reaction: RAPD). From the investigation of clinical backgrounds of two patients who isolated bacterial strains, September 18, 2004. 10 : 20 a.m., and 10 : 40 a.m., other chances that can become with contact infection in this hospital, except conducted X-Ray or roentgenograph of the chest and abdomen of Portable X-ray device continuously done by one radiation technician was not seen. Because it had turned out that a radiation technician who had taken charge had been neglecting the hand washing at the time of each X-Ray or roentgenograph, it was guessed the case with nosocomial infection by contact infection occurred via specific radiation technician.