Epidemiology and antimicrobial susceptibility profiles of Enterobacterales causing bloodstream infections before and during COVID-19 pandemic: Results of the Study for Monitoring Antimicrobial Resistance Trends (SMART) in Taiwan, 2018-2021

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has contributed to the spread of antimicrobial resistance, including carbapenem-resistant Enterobacterales.

METHODS

This study utilized data from the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance program in Taiwan. Enterobacterales from patients with bloodstream infections (BSIs) were collected and subjected to antimicrobial susceptibility testing and β-lactamase gene detection using a multiplex PCR assay. Statistical analysis was conducted to compare susceptibility rates and resistance genes between time periods before (2018-2019) and during the COVID-19 pandemic (2020-2021).

RESULTS

A total of 1231 Enterobacterales isolates were collected, predominantly Escherichia coli (55.6%) and Klebsiella pneumoniae (29.2%). The proportion of nosocomial BSIs increased during the COVID-19 pandemic (55.5% vs. 61.7%, p < 0.05). Overall, susceptibility rates for most antimicrobial agents decreased, with Enterobacterales from nosocomial BSIs showing significantly lower susceptibility rates than those from community-acquired BSIs. Among 123 Enterobacterales isolates that underwent molecular resistance mechanism detection, ESBL, AmpC β-lactamase, and carbapenemase genes were detected in 43.1%, 48.8% and 16.3% of the tested isolates, respectively. The prevalence of carbapenemase genes among carbapenem-resistant Enterobacterales increased during the pandemic, although the difference was not statistically significant. Two novel β-lactamase inhibitor combinations, imipenem-relebactam and meropenem-vaborbactam, preserved good efficacy against Enterobacterales. However, imipenem-relebactam showed lower in vitro activity against imipenem-non-susceptible Enterobacterales than that of meropenem-vaborbactam.

CONCLUSIONS

The COVID-19 pandemic appears to be associated with a general decrease in antimicrobial susceptibility rates among Enterobacterales causing BSIs in Taiwan. Continuous surveillance is crucial to monitor antimicrobial resistance during the pandemic and in the future.

A 19-year longitudinal study to characterize carbapenem-nonsusceptible Acinetobacter isolated from patients with bloodstream infections and the contribution of conjugative plasmids to carbapenem resistance and virulence

BACKGROUND

This study aimed to characterize carbapenem-nonsusceptible Acinetobacter (CNSA) isolated from patients with bacteremia from 1997 to 2015.

METHODS

A total of 173 CNSA (12.3%) was recovered from 1403 Acinetobacter isolates. The presence of selected β-lactamase genes in CNSA was determined by PCR amplification. The conjugation test was used to determine the transferability of metallo-β-lactamase (MBL)-carrying plasmids. Whole genome sequencing in combination with phenotypic assays was carried out to characterize MBL-plasmids.

RESULTS

In general, a trend of increasing numbers of CNSA was observed. Among the 173 CNSA, A. baumannii (54.9%) was the most common species, followed by A. nosocomialis (23.1%) and A. soli (12.1%). A total of 49 (28.3%) CNSA were extensively drug-resistant, and all were A. baumannii. The most common class D carbapenemase gene in 173 CNSA was blaOXA-24-like (32.4%), followed by ISAba1-blaOXA-51-like (20.8%), ISAba1-blaOXA-23 (20.2%), and IS1006/IS1008-blaOXA-58 (11.6%). MBL genes, blaVIM-11,blaIMP-1, and blaIMP-19 were detected in 9 (5.2%), 20 (11.6%), and 1 (0.6%) CNSA isolates, respectively. Transfer of MBL genes to AB218 and AN254 recipient cells was successful for 7 and 6 of the 30 MBL-plasmids, respectively. The seven AB218-derived transconjugants carrying MBL-plasmids produced less biofilm but showed higher virulence to larvae than recipient AB218.

CONCLUSIONS

Our 19-year longitudinal study revealed a stable increase in CNSA during 2005-2015. blaOXA-24-like, ISAba1-blaOXA-51-like, and ISAba1-blaOXA-23 were the major determinants of Acinetobacter carbapenem resistance. MBL-carrying plasmids contribute not only to the carbapenem resistance but also to A. baumannii virulence.

Minimum inhibitory concentrations of antifungals against invasive isolates of Cryptococcus species worldwide: Global antifungal antimicrobial testing leadership and surveillance program, 2010-2020

This study examined the geographic distribution of minimum inhibitory concentrations (MICs) of antifungals against Cryptococcus isolates. Data were collected on the MICs of specific antifungals (amphotericin B, 5-flucytosine, fluconazole, voriconazole, posaconazole, and isavuconazole) against various Cryptococcus species for the period 2010 to 2020 from the Antimicrobial Testing Leadership and Surveillance database. Cryptococcus isolates were collected from samples of blood and cerebrospinal fluid (CSF) from patients hospitalized in different regions worldwide. We applied the epidemiological cutoff values (ECVs) of antifungals against various Cryptococcus species to distinguish wild-type (WT) from non-WT Cryptococcus isolates. A total of 395 isolates of Cryptococcus species cultured from blood (n = 201) or CSF (n = 194) were analyzed. C. grubii (n = 270), C. neoformans (n = 111), and C. gattii (n = 11) were the three predominant species causing bloodstream infections (BSI) or meningitis/meningoencephalitis (MME). The proportion of MICs above the ECV (1 mg/L) for amphotericin B among C. neoformans isolates was significantly lower than that among C. gattii isolates (MICs >0.5 mg/L; P < 0.001), as evaluated using the chi-square test. For most isolates of the three predominant Cryptococcus species, the MICs of new triazoles were ≤0.25 mg/L. The MICs of fluconazole and amphotericin B in the BSI/MME-causing Cryptococcus isolates collected from patients hospitalized in the Asia-Western Pacific region and Europe were significantly lower (i.e., the distributions were more leftward) than those in North America and Latin America. Ongoing monitoring of MIC data for important antifungals against cryptococcosis is crucial.

In vitro antimicrobial susceptibility data of global meropenem-resistant Acinetobacter baumannii isolates causing pneumonia: Data from the Antimicrobial Testing Leadership and Surveillance Program, 2014-2021, and re-estimations of susceptibility breakpoints and appropriate dosages of important antibiotics for pneumonia treatment

OBJECTIVES

To evaluate the susceptibility of globally pneumonia-causing meropenem-resistant (MEM-R) Acinetobacter baumannii isolates against important antibiotics and estimate appropriate dosages of indicated antibiotics.

METHODS

We extracted the 2014-2021 Antimicrobial Testing of Leadership Surveillance database regarding the susceptibility of MEM-R A. baumannii isolates causing pneumonia against important antibiotics. The susceptibility and carbapenemase-encoding gene (CPEG) data of pneumonia-causing MEM-R A. baumannii isolates from patients hospitalized in intensive care units of five major regions were analyzed. The susceptibility breakpoints (SBP) recommended by the Clinical and Laboratory Standards Institute (CLSI) in 2022, other necessary criteria [SBP of MIC for colistin, 2 mg/L, in the CLSI 2018; and cefoperazone-sulbactam (CFP-SUL), 16 mg/L], and the pharmacokinetic and pharmacodynamic data of indicated antibiotics were employed.

RESULTS

Applying the aforementioned criteria, we observed the susceptible rates of colistin, minocycline, and CFP-SUL against the pneumonia-causing MEM-R A. baumannii isolates globally (n = 2905) were 93.2%, 69.1%, and 26.3%, respectively. Minocycline was significantly more active in vitro (MIC ≤4 mg/L) against the pneumonia-causing MEM-R A. baumannii isolates collected from North and South America compared to those from other regions (>90% vs. 58-72%). Additionally, blaOXA-23 and blaOXA-72 were the predominant CPEG in pneumonia-causing MEM-R A. baumannii isolates.

CONCLUSIONS

After deliberative estimations, dosages of 200 mg minocycline intravenously every 12 h (SBP, 8 mg/L), 100 mg tigecycline intravenously every 12 h (SBP, 1 mg/L), and 160 mg nebulized colistin methanesulphonate every 8 h (SBP, 2 mg/L) are needed for the effective treatment of pneumonia-causing MEM-R A. baumannii isolates.

Conserved molecular chaperone PrsA stimulates protective immunity against group A Streptococcus

Group A Streptococcus (GAS) is a significant human pathogen that poses a global health concern. However, the development of a GAS vaccine has been challenging due to the multitude of diverse M-types and the risk of triggering cross-reactive immune responses. Our previous research has identified a critical role of PrsA1 and PrsA2, surface post-translational molecular chaperone proteins, in maintaining GAS proteome homeostasis and virulence traits. In this study, we aimed to further explore the potential of PrsA1 and PrsA2 as vaccine candidates for preventing GAS infection. We found that PrsA1 and PrsA2 are highly conserved among GAS isolates, demonstrating minimal amino acid variation. Antibodies specifically targeting PrsA1/A2 showed no cross-reactivity with human heart proteins and effectively enhanced neutrophil opsonophagocytic killing of various GAS serotypes. Additionally, passive transfer of PrsA1/A2-specific antibodies conferred protective immunity in infected mice. Compared to alum, immunization with CFA-adjuvanted PrsA1/A2 induced higher levels of Th1-associated IgG isotypes and complement activation and provided approximately 70% protection against invasive GAS challenge. These findings highlight the potential of PrsA1 and PrsA2 as universal vaccine candidates for the development of an effective GAS vaccine.

Liver dysfunction and clinical outcomes of unvaccinated COVID-19 patients with and without chronic hepatitis B

BACKGROUND

Liver dysfunction is common during coronavirus disease 2019 (COVID-19), while its clinical impact and association with chronic hepatitis B (CHB) remain uncertain. We aimed to investigate liver dysfunction in COVID-19 patients and its impacts on those with/without CHB.

METHODS

We conducted a retrospective cohort study of COVID-19 patients at National Taiwan University Hospital, stratified according to hepatitis B surface antigen (HBsAg) serostatus, with demographics, laboratory data, and hospitalization course reviewed, and clinical outcomes compared through multivariable analyses.

RESULTS

We enrolled 109 COVID-19 patients unvaccinated against SARS-CoV-2 by August 2021. The HBsAg-positive group (n = 34) had significantly higher alanine aminotransferase (ALT) (26 vs. 16 U/L, P = 0.034), platelet (224 vs. 183 k/μL, P = 0.010) and longer hospitalizations (17 vs. 13 days, P = 0.012) compared with HBsAg-negative group (n = 75), while percentages of hepatitis (2-fold ALT elevation), oxygen supplementation, ventilators usage, COVID-specific treatment, intensive care unit (ICU) admission and mortality were comparable. Older age (odds ratio [OR]: 1.04, 95 % confidence interval [CI]: 1.00-1.08, P = 0.032) and higher aspartate aminotransferase (AST) (OR: 1.08, 95 % CI: 1.004-1.16, P = 0.038) were associated with oxygen supplementation according to multivariable analyses. Higher AST predicted ICU admission (OR: 1.11, 95 % CI: 1.03-1.19, P = 0.008). Oxygen usage (OR: 5.64, 95 % CI: 1.67-19.09, P = 0.005) and shock (OR: 5.12, 95 % CI: 1.14-22.91, P = 0.033) were associated with liver dysfunction.

CONCLUSIONS

CHB patients had higher ALT levels and longer hospitalizations during COVID-19. Higher AST levels predict severe COVID-19 and ICU admission.

Microbiological persistence in patients with Mycobacterium abscessus complex lung disease: The prevalence, predictors, and the impact on progression

OBJECTIVES

Persistent growth of Mycobacterium abscessus complex (MABC) in the respiratory system is not uncommon and may indicate continuous infection of MABC lung disease (MABC-LD), but its prevalence, risk factors, and clinical impact have not been investigated.

METHODS

The present study was conducted in two medical centers in northern Taiwan. We enrolled patients with MABC-LD and investigated the prevalence and predictors of persistent culture positivity (MABC-PP). Furthermore, we analyzed the association between MABC-PP and radiographic or clinical progression.

RESULTS

Among 189 patients with MABC-LD, 58 were in the MABC-PP group. Independent predictors for MABC-PP included an increasing radiographic score and highest acid-fast stain (AFS) of strong positivity (3-4+) at initial diagnosis (compared with negative AFS). MABC-PP and highest AFS were independently associated with MABC-LD progression by the multivariable analysis model. The adjusted hazard ratio increased to 3.56 when the two independent factors existed.

CONCLUSIONS

MABC-PP accounted for 30.7% and was predicted by initial AFS grade and radiographic score. Patients with MABC-PP, and highest AFS grade might have disease progression.

Clinical significance of mutations in dihydropteroate synthase in Pneumocystis jirovecii pneumonia among non-HIV-infected patients

BACKGROUND

Dihydropteroate synthase (DHPS) mutations may be associated with trimethoprim-sulfamethoxazole resistance in Pneumocystis jirovecii pneumonia (PCP) and worse clinical outcomes. However, the clinical significance of DHPS mutations in PCP among non-human immunodeficiency virus (HIV)-infected patients remains unclear.

METHODS

Patients with PCP in three tertiary referral hospitals in Taiwan between 2016 and 2020 were retrospectively enrolled. Two point mutations, Thr55Ala and Pro57Ser, in the DHPS protein were analysed. Patients with invalid DHPS mutations in the respiratory specimen, chronic respiratory failure, receiving endotracheal intubation for surgical intervention, HIV infection, Pneumocystis jirovecii colonisation, and no lactate dehydrogenase (LDH) data were excluded. The primary outcome was 30-day survival.

RESULTS

A total of 215 patients were analysed. Mutants inside DHPS were found in 78 patients (36.3%) and 68 patients (31.6%) died within 30 days. A total of 214 patients (99.5%) received trimethoprim-sulfamethoxazole as the first-line treatment. The rates of mechanical ventilation, 30-day, and in-hospital mortality were similar between wild-type and mutant DHPS PCP. After adjusting for important confounders, LDH > 500 µ/L (adjusted hazard ratio [aHR] = 2.448, P = 0.001), pneumonia severity index > 135 mg/dL (aHR = 1.689, P = 0.049), and having solid tumours (aHR = 1.832, P = 0.034) were independently associated with higher mortality. In subgroup analysis, mutant DHPS PCP patients had less 30-day mortality among patients aged > 65 years (P = 0.049), with lymphopenia (P = 0.040), and those without solid tumour (P = 0.045).

CONCLUSIONS

In non-HIV-infected PCP, point mutants inside DHPS may not be associated with trimethoprim-sulfamethoxazole treatment outcomes. Further prospective large-scale studies are warranted.

[Clinical effects of anterolateral thigh flap with blood supply source of medial femoral perforator in repairing the wounds on extremities]

Objective: To investigate clinical effects of anterolateral thigh flap with blood supply source of medial femoral perforator in repairing the wounds on extremities. Methods: A retrospective observational study was conducted. From October 2018 to June 2021, Suzhou Ruihua Orthopedic Hospital admitted 12 patients (11 males and 1 female, aged 24-64 years) who met the inclusion criteria, and did not have the lateral circumflex femoral artery during anterolateral thigh flap resection, or changed to medial femoral perforator as a source of blood supply due to small perforator to repair the wound with flap transplantation. The wounds were on the upper limbs in 7 cases and on the lower limbs in 5 cases. The wound area after debridement was 8.0 cm×5.0 cm-24.0 cm×6.5 cm, and the applied flap area was 9 cm×6 cm-25 cm×7 cm. During transplantation, the perforating branch or source artery of the flap was anastomosed end to end with the vascular pedicle of the recipient area. Subcutaneous beauty suture was performed on all the donor wounds. After operation, the survival of the flap and vascular crisis were observed; and the wound healing at the donor site was observed. During follow-up, the texture of the flap and complications at the donor site were observed. At the last follow-up, the effect of flap repair was evaluated by using the modified self-made comprehensive efficacy rating table. Results: After operation, all the flaps of patients survived without vascular crisis; the wounds in the donor site healed smoothly. During follow-up of 6 to 26 months, the flaps had good texture; only linear scars remained in the donor area without scar contracture, pain or other discomfort. At the last follow-up, the total score of flap repair effect of 12 patients was 75-95, with an average of 87, of which 5 cases were rated as excellent, 6 cases as good, and 1 case as fair, and the proportion of excellent and good patients was 11/12. Conclusions: The application of anterolateral thigh flap with blood supply from the medial femoral perforator to repair wounds on extremities is an alternative method for the vascular variations such as no descending branch, oblique branch, or small perforator of the lateral circumflex femoral artery during the resection of the anterolateral thigh flap. This operation has the advantages of simple operation, small trauma, and others, which effectively ensures the smooth operation.

Humeral and cellular immune responses to SARS-CoV-2 vaccination in patients on peritoneal dialysis

BACKGROUND

Patients with chronic kidney disease are at high risk for coronavirus disease 2019. Little is known about immune response to severe acute respiratory syndrome coronavirus 2 vaccination in patients on peritoneal dialysis (PD).

METHOD

We prospectively enrolled 306 PD patients receiving two doses of vaccines (ChAdOx1-S: 283, mRNA-1273: 23) from July 2021 at a medical center. Humeral and cellular immune responses were assessed by anti-spike IgG concentration and blood T cell interferon-γ production 30 days after vaccination. Antibody ≥0.8 U/mL and interferon-γ ≥ 100 mIU/mL were defined as positive. Antibody was also measured in 604 non-dialysis volunteers (ChAdOx1-S: 244, mRNA-1273: 360) for comparison.

RESULT

PD patients had less adverse events after vaccinations than volunteers. After the first dose of vaccine, the median antibody concentrations were 8.5 U/mL and 50.4 U/mL in ChAdOx1-S group and mRNA-1273 group of PD patients, and 66.6 U/mL and 195.3 U/mL in ChAdOx1-S group and mRNA-1273 group of volunteers, respectively. And after the second dose of vaccine, the median antibody concentrations were 344.8 U/mL and 9941.0 U/mL in ChAdOx1-S group and mRNA-1273 group of PD patients, and 620.3 U/mL and 3845.0 U/mL in ChAdOx1-S group and mRNA-1273 group of volunteers, respectively. The median IFN-γ concentration was 182.8 mIU/mL in ChAdOx1-S group, which was substantially lower than the median concentration 476.8 mIU/mL in mRNA-1273 group of PD patients.

CONCLUSION

Both vaccines were safe and resulted in comparable antibody seroconversion in PD patients when compared with volunteers. However, mRNA-1273 vaccine induced significantly higher antibody and T cell response than ChAdOx1-S in PD patients. Booster doses are recommended for PD patients after two doses of ChAdOx1-S vaccination.

Applicability of an in-house extraction protocol in a Bruker Biotyper matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system for the identification of Streptococcus agalactiae from broth-enriched vaginal/rectal swab specimens

BACKGROUND AND PURPOSE

Early laboratory identification of group B Streptococcus (GBS, Streptococcus agalactiae) in the birth canal of pregnant women is critical for prompt administration of antimicrobial therapy and may further reduce the mortality rate due to GBS neonatal infection.

METHODS

A total of 164 vaginal/rectal swab specimens collected from pregnant women at 35-37 weeks of gestation were screened for GBS vaginal colonization. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS, Bruker Biotyper, Bruker Daltonik GmbH, Bremen, Germany) system was used to detect GBS from Carrot broth and LIM broth enrichment using an in-house extraction protocol. The results were compared to those by conventional broth-enriched culture/identification methods as the gold standard. BD MAX™ GBS assay (Becton Dickinson, Sparks, MD, USA) was also performed for Carrot broth-enriched specimen. Discordant results were investigated using the GeneXpert® GBS PCR assay (Cepheid Inc., Sunnyvale, CA, USA).

RESULTS

Using the extraction protocol, 33 (20.1%) of the 164 specimens were positive in Carrot broth, and 19 (11.6%) were positive in LIM broth. Using the culture protocol, 38 (23.2%) samples in Carrot broth and 35 (21.3%) in LIM broth were positive. The sensitivity, specificity, and positive and negative predictive values using the extraction protocol in Carrot broth and LIM broth compared to the gold standard conventional culture/identification method were 86.8% and 50.0%, 100% and 100%, 100% and 100%, and 96.2% and 86.9%, respectively.

CONCLUSIONS

The extraction protocol with MALDI-TOF MS from Carrot broth-enriched samples provides a more rapid turnaround time, lower cost, and acceptable sensitivity and specificity to correctly identify pathogens when compared to conventional culture/identification methods.

[Effects of bilobated superficial peroneal artery perforator flap in repairing two adjacent wounds of the fingers]

Objective: To investigate the therapeutic efficacy of bilobated superficial peroneal artery perforator flap in repairing two adjacent wounds of the fingers. Methods: A retrospective observational study was conducted. From January 2021 to January 2022, 15 patients with two adjacent wounds of the fingers who met the inclusion criteria were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 10 males and 5 females, aged 25 to 51 years. The area of single wound after debridement was from 2.5 cm×2.0 cm to 7.5 cm×2.5 cm. All the wounds were repaired by the bilobated superficial peroneal artery perforator flap from the lower leg. The single lobe area of bilobated flap was from 3.0 cm×2.0 cm to 8.0 cm×3.0 cm. The wounds in all the donor sites were sutured directly. During the operation, the number of resected flaps, the number and type of carried perforators were recorded, and the calibers of perforator and superficial peroneal artery and the length of vascular pedicle were measured. The survival of flap and the wound healing in the donor and recipient sites were recorded after operation. The recovery of donor and recipient sites were recorded during follow-up. At the last follow-up, the repair effect of flap was evaluated by the comprehensive evaluation scale, and the sensory function of flap was evaluated by the sensory function evaluation standard of British Medical Research Association. Results: During the operation, 15 bilobated flaps were successfully resected, carrying 36 superficial peroneal artery perforators, all of which were septocutaneous perforators with the caliber of 0.2-0.8 mm. The caliber of superficial peroneal artery was 0.4-1.1 mm and the length of vascular pedicle was 3-8 cm. After operation, all the flaps survived with no vascular crisis occurred, and the wounds in donor and recipient sites healed well. During the follow-up of 6 to 12 months, the color and texture of flaps were similar to those of normal tissue in the hand and the appearance of flap was good in 10 cases; the other 5 cases underwent the stage Ⅱ flap thinning and plastic surgery 6 months after operation due to the bloated appearance of flaps. There was only linear scar in the donor site of lower leg, with no obvious scar hyperplasia or pigmentation, and there was no obvious adverse effect on the sensation or motor function of the distal limbs in the donor area. At the last follow-up, the repair effect of flap of 15 patients was excellent in 11 cases and good in 4 cases, and the sensory function of the flap was evaluated as grade S2 in all cases. Conclusions: The bilobated superficial peroneal artery perforator flap has high proportion of septocutaneous perforator, and the blood supply is sufficient and reliable. Using this flap to repair two adjacent wounds of the fingers causes minimal damage to the donor area, only one group of blood vessels is needed to be anastomosed to repair two wounds, the difficulty of microoperation is reduced, and good flap repair effect and sensory function can be obtained.

Protective Effect of Vaccine Doses and Antibody Titers Against SARS-CoV-2 Infection in Kidney Transplant Recipients

Patients undergoing kidney transplantation have a poor response to vaccination and a higher risk of disease progression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The effectiveness of vaccine doses and antibody titer tests against the mutant variant in these patients remains unclear. We retrospectively analyzed the risk of SARS-CoV-2 infection in a single medical center according to vaccine doses and immune responses before the outbreak. Among 622 kidney transplant patients, there were 77 patients without vaccination, 26 with one dose, 74 with two doses, 357 with three, and 88 with four doses. The vaccination status and infection rate proportion were similar to the general population. Patients undergoing more than three vaccinations had a lower risk of infection (odds ratio = 0.6527, 95% CI = 0.4324-0.9937) and hospitalization (odds ratio = 0.3161, 95% CI = 0.1311-0.7464). Antibody and cellular responses were measured in 181 patients after vaccination. Anti-spike protein antibody titer of more than 1,689.3 BAU/mL is protective against SARS-CoV-2 infection (odds ratio = 0.4136, 95% CI = 0.1800-0.9043). A cellular response by interferon-γ release assay was not correlated with the disease (odds ratio = 1.001, 95% CI = 0.9995-1.002). In conclusion, despite mutant strain, more than three doses of the first-generation vaccine and high antibody titers provided better protection against the omicron variant for a kidney transplant recipient.

[Morphological study on the transverse branch of lateral femoral circumflex artery based on digital subtraction angiography]

Objective: To summarize the morphological characteristics of the transverse branch of lateral femoral circumflex artery (LFCA) using digital subtraction angiography (DSA) and explore its clinical significance. Methods: A retrospective observational study was conducted. From October 2020 to May 2021, 62 patients with soft tissue injuries in the extremities were hospitalized in Suzhou Ruihua Orthopedic Hospital, including 40 males and 22 females, aged from 20 to 72 years. DSA was performed in the lateral femoral region of patients before the anterolateral thigh flap transplantation, and in combination with imaging scale to observe and measure the general condition of the blood vessels and the occurrence (with the occurrence rate being calculated), source artery, location of the origin point, direction of course, and the location of the perforating point of the cutaneous perforator of the transverse branch of LFCA, and in addition to classify the morphological characteristics of the transverse branch. Results: DSA detection showed that the femoral artery, the deep femoral artery, and the branches of LFCA were clearly distinguishable in 62 patients. Transverse branches of LFCA were observed in 59 patients, including 52 cases with a single transverse branch, and 7 cases with double transverse branches. The occurrence rate of transverse branches was 95.2% (59/62). A total of 66 transverse branches of LFCA were observed, of which 3 originated from the deep femoral artery, and 63 originated from the LFCA. The origin point of the transverse branch was 6.5-12.7 cm away from the anterior superior iliac spine. The transverse branch which was approximately perpendicular to the long axis of the body, originated outwards, ran between the ascending branch of LFCA and the oblique branch of LFCA, and branched along the way, with the trunk running under the greater trochanter. The perforating point of the cutaneous perforator of the transverse branch was 8.0-18.0 cm away from the anterior superior iliac spine. In the classification of morphological characteristics of the transverse branch of LFCA, the most common type was the one that originated from the same trunk with other branches of LFCA, accounting for 50.0% (31/62), followed by the one that originated from the singular trunk of LFCA (12 cases) or deep femoral artery (3 cases), accounting for 24.2% (15/62); the special type accounted for 21.0% (13/62), including 7 cases of double transverse branches and 6 cases of the transverse branch originated from the same trunk with multiple other branches of LFCA; those with small/absent transverse branch only accounted for 4.8% (3/62). Among the above-mentioned common trunk relationship of two branches, those with shared trunk of ascending and transverse branches were most frequently observed, accounting for 77.4% (24/31); those with shared trunks of the transverse and oblique branches (5 cases) and the transverse and descending branches (2 cases) accounted for 22.6% (7/31) altogether. Conclusions: A high incidence rate of the transverse branch of LFCA is observed through DSA. The transverse branch originates from the lateral femoral artery approximately perpendicular to the long axis of the body, mainly from the same trunk with another main branch of LFCA, especially the ascending branch. This positioning analysis can provide an important reference for the design and resection of anterolateral femoral flaps.

In vitro activity of imipenem/relebactam, meropenem/vaborbactam and comparators against Enterobacterales causing urinary tract infection in Taiwan: Results from the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2020

Antimicrobial resistance due to β-lactamase production is a worldwide problem, and β-lactamase inhibitors have been developed to overcome the growing resistance to β-lactamase. The in vitro activities of two recently introduced carbapenem/β-lactamase inhibitor combinations, imipenem/relebactam and meropenem/vaborbactam, and their comparators against Enterobacterales from patients with urinary tract infection (UTI) were evaluated. Enterobacterales isolates from patients with UTIs in Taiwan participating in the Study for Monitoring Antimicrobial Resistance Trends (SMART) in 2020 were included. Minimum inhibitory concentrations (MICs) for various antibiotics were determined using the broth microdilution method. Susceptibility was interpreted based on the MIC breakpoints of Clinical and Laboratory Standards Institute (CLSI) 2022. Genes encoding common β-lactamases, including extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases (AmpC) and carbapenemases, were detected using multiplex polymerase chain reaction. A total of 309 Enterobacterales isolates were included, against which both imipenem/relebactam and meropenem/vaborbactam exerted excellent efficacy (95% [275/309] and 99.3% [288/309], respectively). Among imipenem-non-susceptible isolates, 39.5% [17/43] and 90.7% [39/43] were susceptible to imipenem/relebactam and meropenem/vaborbactam, respectively. In conclusion, imipenem/relebactam and meropenem/vaborbactam may be appropriate choices for treating UTIs due to Enterobacterales resistant to commonly used antibiotics. Continuous monitoring of antimicrobial resistance is crucial.

[Curative effects of the superficial peroneal artery perforator flap carrying multiple perforators in repairing hand and foot wounds]

Objective: To investigate the curative effects of the superficial peroneal artery perforator flap carrying two and more homologous perforators in repairing hand and foot wounds. Methods: A retrospective observational study was conducted. From January to September 2021, 23 patients with hand and foot wounds combined with bone or tendon exposure who met the inclusion criteria were admitted to Suzhou Ruihua Orthopaedic Hospital, including 16 males and 7 females, aged 23 to 68 years. After expansion of the wound, the wound area was 3.0 cm×2.0 cm to 11.0 cm×4.0 cm. All the wounds were repaired with the superficial peroneal artery perforator flap carrying two and more homologous perforators. The area of the resected flap was 4.0 cm×2.0 cm to 12.0 cm×5.0 cm. All the wounds in donor areas were sutured directly. During the operation, the resection of the flap, the number and caliber of carried perforators, the caliber of superficial peroneal artery, the length of vascular pedicle, and the number of accompanying veins of the superficial peroneal artery were recorded. The survival of the flap, the occurrence of complications, and the wound healing in the donor area were observed after operation. The recovery of the donor and recipient areas was followed up. At the last follow-up, the comprehensive evaluation scale was used to evaluate the curative effect of flap repair, and the sensory grading scale was used to evaluate the sensory function of the recipient area. Results: Totally 24 flaps were successfully resected in surgical operations, carrying 56 superficial peroneal artery perforators in total, with the caliber of perforators of 0.20-0.70 mm. The calibers of all perforators carried by 7 flaps were smaller than 0.40 mm. Nineteen flaps carried 2 perforators each, 3 flaps carried 3 perforators each, 1 flap carried 4 perforators, and 1 flap carried 5 perforators. During the operation, the superficial peroneal artery was resected with a caliber of 0.40-1.50 mm, the vascular pedicle was 2-6 cm in length, and each superficial peroneal artery had two accompanying veins. After operation, all the flaps survived smoothly, no vascular crisis or distal necrosis occurred, and the wounds healed well in the donor area. During the follow-up of 6 to 10 months after operation, the color, texture, and elasticity of the recipient area were good. Among them, 6 recipient areas were thinned and reshaped because of bloating. There was only linear scar and no obvious scar hyperplasia or pigmentation in the donor area, without significant change in sensory or motor function. At the last follow-up, the curative effect evaluation of flap repair was excellent in 22 flaps and good in 2 flaps, and the sensory function evaluation of the recipient area was grade S3 in 1 area and grade S2 in 23 areas. Conclusions: The superficial peroneal artery perforator flap with two and more homologous perforators has sufficient and reliable blood supply and is effective in repairing hand and foot wounds. It provides an ideal solution for the clinical problem in which the original operation scheme is abandoned due to the existence of only multiple slender perforators of caliber smaller than 0.40 mm, and only a single perforator in the operative field that cannot satisfy the needs of the flap blood supply and recipient area.

Genome-based characterization of conjugative IncHI1B plasmid carrying carbapenemase genes blaVIM-1, blaIMP-23, and truncated blaOXA-256in Klebsiella pneumoniae NTU107224

The wide dissemination of plasmids carrying antibiotic resistance determinants among bacteria is a severe threat to global public health. Here, we characterized an extensively drug-resistant (XDR) Klebsiella pneumoniae NTU107224 by whole genome sequencing (WGS) in combination with phenotypic tests. Broth dilution method was used to determine the minimal inhibitory concentrations (MICs) of NTU107224 to 24 antibiotics. The whole genome sequence of NTU107224 was determined by Nanopore/Illumina hybrid genome sequencing. Conjugation assay was performed to determine the transferability of plasmids in NTU107224 to recipient K. pneumoniae 1706. Larvae infection model was used to determine the effect(s) of conjugative plasmid pNTU107224-1 on bacterial virulence. Among the 24 antibiotics tested, XDR K. pneumoniae NTU107224 had low MICs only for amikacin (≤1 μg/mL), polymyxin B (0.25 μg/mL), colistin (0.25 μg/mL), eravacycline (0.25 μg/mL), cefepime/zidebactam (1 μg/mL), omadacycline (4 μg/mL), and tigecycline (0.5 μg/mL). Whole genome sequencing showed that the closed NTU107224 genome comprises a 5,076,795-bp chromosome, a 301,404-bp plasmid named pNTU107224-1, and a 78,479-bp plasmid named pNTU107224-2. IncHI1B plasmid pNTU107224-1 contained three class 1 integrons accumulated various antimicrobial resistance genes (including carbapenemase genes bla_VIM-1, bla_IMP-23, and truncated bla_OXA-256) and the blast results suggested the dissemination of IncHI1B plasmids in China. By day 7 after infection, larvae infected with K. pneumoniae 1706 and transconjugant had 70% and 15% survival rates, respectively. We found that the conjugative plasmid pNTU107224-1 is closely related to IncHI1B plasmids disseminated in China and contributes to the virulence and antibiotic resistance of pathogens.

Prolonged Streptococcus gallolyticus subsp. pasteurianus gut colonization in healthcare workers and potential transmission role in neonatal sepsis

BACKGROUND

Streptococcus gallolyticus subsp. pasteurianus (SGSP) is a commensal in the intestinal tract and a potential pathogen of neonatal sepsis. During an 11-month period, four consecutive cases of SGSP sepsis were identified in one postnatal care unit (unit A) without evidence of vertical transmission. Therefore, we initiated this study to investigate the reservoir and mode of transmission of SGSP.

METHOD

We performed cultures of stool samples from healthcare workers in unit A and unit B (another unit without SGSP sepsis). If SGSP was positive in feces, we performed isolate pulsotyping and genotyping by using pulsed-field gel electrophoresis (PFGE) and analyzing random amplified polymorphic DNA (RAPD) patterns, respectively.

RESULTS

Five staff members in unit A showed positivity for SGSP. All samples from unit B were negative. We identified two major pulsogroups (groups C and D) by PFGE. In group D, the strains isolated from 3 consecutive sepsis patients (P1, P2 and P3) were closely related and clustered together as those from 2 staff members (C1/C2, C6). One staff (staff 4) had a direct contact history with patient (P1) confirmed to have the same clone. The last isolate of the patient in our study (P4) belonged to a distinct clone.

CONCLUSION

We found prolonged gut colonization of SGSP in healthcare workers and its epidemiological relatedness to neonatal sepsis. Fecal-oral or contact transmission is a possible route of SGSP infection. Fecal shedding among staff may be associated with neonatal sepsis in healthcare facilities.

Performance of two commercial multiplex polymerase chain reaction assays for the etiological diagnosis of sexually transmitted infections among men who have sex with men

BACKGROUND AND PURPOSE

This study aimed to investigate the etiologies of sexually transmitted infections (STIs) among men who have sex with men (MSM) in Taiwan.

METHODS

Two commercial assays, the BD MAX Chlamydia trachomatis (CT), Neisseria gonorrhoeae (GC), and Trichomonas vaginalis (TV) panel and the Allplex™ STI Essential assay (CT, GC, Mycoplasma genitalium [MG], Mycoplasma hominis [MH], Ureaplasma urealyticum [UU], Ureaplasma parvum [UP], and TV) were evaluated. During the first stage, urine and rectal swab samples from 168 patients were evaluated using the BD MAX assay, and the multiplex RT-PCR Allplex™ STI Essential assay was applied only to the patients with positive results on the BD MAX asay (n = 49). During the second stage, urine and rectal swab samples from 90 patients were evaluated using the BD MAX assay and the Allplex™ qPCR.

RESULTS

The Allplex qPCR identified all CT, missed one and additionally one TV from the positive samples (n = 49) by the BD MAX assay in the first stage. At the second stage, both commercial assays showed similar detection rate of CT, NG or CT/NG coinfection (11.1%, 1.1% and 4.4% by the BD MAX assay; 10.0%, 1.1% and 2.2% by the Allplex qPCR). The positivity rates of MG, MH, and UU by the Allplex qPCR were 4.4%, 2.2%, and 12.2%, respectively, for urine samples and 10%, 13.3%, and 22.2%, respectively, for anal swab samples.

CONCLUSIONS

High rates of STI-associated etiologies were observed in MSM. The positive rates were higher in rectal swabs than in urine samples.

Molecular epidemiology of bacteraemic vancomycin-resistant Enterococcus faecium isolates and in vitro activities of SC5005 and other comparators against these isolates collected from a medical centre in northern Taiwan, 2019-2020

OBJECTIVES

The global prevalence of vancomycin-resistant Enterococcus faecium (VREfm) highlights the need for new anti-enterococcal agents. Here, we assessed the molecular epidemiology of clinical VREfm bacteraemic isolates from a medical centre in northern Taiwan in 2019-2020 and to evaluate their susceptibility to last-line antibiotics and a new antimicrobial agent, SC5005.

METHODS

The molecular epidemiology of VREfm was investigated using van genotyping, MLST and PFGE. The susceptibilities of VREfm strains to antibiotics and SC5005 were determined using the agar dilution and broth microdilution methods. The capability of E. faecium to develop resistance to antibiotics and SC5005 was evaluated using frequency of resistance and multipassage resistance assays. The mode of action of SC5005 was assessed by time-kill, bacterial membrane integrity and membrane potential assays.

RESULTS

All 262 VREfm isolates harboured vanA gene, and the most prevalent sequence type was ST17 (51%, n = 134, 84 pulsotypes), followed by ST78 (25%, n = 65, 54 pulsotypes). Additionally, we identified four new STs (ST2101, ST2102, ST2135 and ST2136) and observed the arrival of multidrug-resistant ST1885 in Taiwan. Moreover, SC5005 was effective against all VREfm isolates, including those non-susceptible to last-line antibiotics. SC5005 can disrupt and depolarize the bacterial membrane to kill E. faecium without detectable resistance.

CONCLUSIONS

The findings provide insights into the latest epidemiology and resistance profiles of bacteraemic-causing VREfm in northern Taiwan. Additionally, SC5005 has the potential for development as a new therapeutic to treat VREfm infections.

In Vitro Susceptibilities of Worldwide Isolates of Intrapulmonary Aspergillus Species and Important Candida Species in Sterile Body Sites against Important Antifungals: Data from the Antimicrobial Testing Leadership and Surveillance Program, 2017-2020

To understand the changes of resistance in clinically commonly encountered fungi, we used the Antimicrobial Testing Leadership and Surveillance (ATLAS) database to explore in vitro antifungal susceptibilities against clinically important isolates of Aspergillus and Candida species (collected from intrapulmonary and sterile body areas, respectively). We applied the CLSI antifungal 2020 and the EUCAST antifungal 2020 guidelines. From 2017 to 2020, isolates of intrapulmonary Aspergillus fumigatus (n = 660), Aspergillus niger (n = 107), Aspergillus flavus (n = 96), Aspergillus terreus (n = 40), and Aspergillus nidulans species complex (n = 26) and sterile site-originated isolates of Candida albicans (n = 1,810), Candida glabrata (n = 894), Candida krusei (n = 120), Candida dubliniensis (n = 107), Candida lusitaniae (n = 82), Candida guilliermondii (n = 28), and Candida auris (n = 7) were enrolled in this study. Using the EUCAST 2020 breakpoints, it was demonstrated that amphotericin B and posaconazole displayed poor in vitro susceptibility rates against A. fumigatus isolates (<50% and 18.9%, respectively). In contrast, isavuconazole and itraconazole showed high in vitro potency against most Aspergillus isolates (>92%). Most intrapulmonary Aspergillus isolates exhibited MICs of ≤0.06 μg/mL to anidulafungin. Furthermore, intrapulmonary A. fumigatus isolates collected from Italy and the United Kingdom exhibited lower in vitro susceptibility to isavuconazole (72.2% and 69%, respectively) than those in the remaining ATLAS participant countries (>85%). Higher isavuconazole MIC90s against C. auris and C. guilliermondii (1 and 4 μg/mL, respectively) were observed compared to the other five Candida species. Despite the aforementioned MICs and susceptibilities against fungi, research needs to consider the pharmacokinetic (PK) profiles, pharmacodynamic (PD) parameters, and clinical treatment experience with antifungals against specific Aspergillus species. IMPORTANCE In addition to monitoring the antifungal susceptibilities of clinically important fungi, reviewing the PK/PD indices and the clinical therapy experience of antifungals under evaluation are important to guide an appropriate antifungal prescription. The efficacies of liposomal amphotericin B complex and anidulafungin for the treatment of pulmonary aspergillosis caused by different Aspergillus species need to be periodically evaluated in the future.

Genomic Surveillance of Listeria monocytogenes in Taiwan, 2014 to 2019

Listeria monocytogenes is a life-threatening foodborne pathogen. Here, we report the genomic characterization of a nationwide dataset of 411 clinical and 82 food isolates collected in Taiwan between 2014 and 2019. The observed incidence of listeriosis increased from 0.83 to 7 cases per million population upon implementation of mandatory notification in 2018. Pregnancy-associated cases accounted for 2.8% of human listeriosis and all-cause 7-day mortality was of 11.9% in nonmaternal-neonatal listeriosis. L. monocytogenes was isolated from 90% of raw pork and 34% of chicken products collected in supermarkets. Sublineages SL87, SL5, and SL378 accounted for the majority (65%) of clinical cases. SL87 and SL378 were also predominant (57%) in food products. Five cgMLST clusters accounted for 57% clinical cases, suggesting unnoticed outbreaks spanning up to 6 years. Mandatory notification allowed identifying the magnitude of listeriosis in Taiwan. Continuous real-time genomic surveillance will allow reducing contaminating sources and disease burden. IMPORTANCE Understanding the phylogenetic relationship between clinical and food isolates is important to identify the transmission routes of foodborne diseases. Here, we performed a nationwide study between 2014 and 2019 of both clinical and food Listeria monocytogenes isolates and sequenced their genomes. We show a 9-fold increase in listeriosis reporting upon implementation of mandatory notification. We found that sublineages SL87 and SL378 predominated among both clinical (50%) and food (57%) isolates, and identified five cgMLST clusters accounting for 57% of clinical cases, suggestive of potential protracted sources of contamination over up to 6 years in Taiwan. These findings highlight that mandatory declaration is critical in identifying the burden of listeriosis, and the importance of genome sequencing for a detailed characterization of the pathogenic L. monocytogenes genotypes circulating in Asia.

[Anatomical characteristics and clinical application of anterolateral thigh perforator flap pedicled with oblique branch trunk of lateral circumflex femoral artery in the muscular septum]

Objective: To explore the anatomical characteristics of the anterolateral thigh perforator flap pedicled with oblique branch trunk of lateral circumflex femoral artery in the muscular septum and the clinical effect of this flap in repairing skin and soft tissue defects in the extremities. Methods: A retrospective observational study was conducted. From December 2020 to April 2021, 59 patients with skin and soft tissue defects in the extremities admitted to the Department of Hand Surgery of Suzhou Ruihua Orthopaedic Hospital met the inclusion criteria, including 46 males and 13 females, aged 20 to 81 years. The wound area after debridement ranged from 8 cm×5 cm to 38 cm×20 cm. According to the condition of the wound, the perforators in the anterolateral femoral region on the unaffected side were located by color Doppler ultrasound. The anterolateral thigh perforator flap with the oblique branch of lateral circumflex femoral artery as the source artery was designed, and the wound was repaired by unilateral flap or series combination of bilateral flaps (with the area of unilateral flap ranging from 7 cm×5 cm to 37 cm×11 cm). The wound of the donor site was sutured directly. The following items were recorded, including the number of perforators in the anterolateral femoral region marked before operation, the course characteristics of oblique branch trunk of lateral circumflex femoral artery and its perforators, and the number, origin, and type of perforators observed during operation, the flap repair mode and the flap harvest time. After operation, the survival condition of the flap, the wound healing time in the recipient site, and the suture healing in the donor area were observed, and the recovery of the donor and recipient areas was followed up. At the last follow-up, the sensation function evaluated by sensory rating scale of British Medical Research Association and two-point discrimination of the area transplanted with flap were recorded, and the improved comprehensive curative effect evaluation scale of flap was used to evaluate the repair effect of the flap. Results: A total of 156 perforators were marked in the anterolateral femoral region before operation, and 144 perforators were observed during the operation, of which 98 came from the oblique branch of the lateral circumflex femoral artery, and the first perforator of the oblique branch was the intermuscular septal perforator. Once formed, most oblique branch trunk of lateral circumflex femoral artery in the muscular septum could be divided into the deep branch and the superficial branch at the middle and upper 1/3 junction of the line between the anterior superior iliac spine and the lateral edge of the patella, the deep branch mainly ran in the muscle of vastus intermedius and vastus lateralis, and rarely developed the skin perforators, while the superficial branch mainly ran in the muscular septum between the rectus femoris and the vastus lateralis, and grew out the perforators to the proximal skin of the anterolateral femoral region. Fifty-six patients were repaired with unilateral flap and 3 patients with bilateral flap in series combination, with the harvesting time of the unilateral flap ranged from 9 to 99 min. Three patients developed arterial crisis within 48 hours after operation and survived after timely exploration; the flap of 1 patient developed necrosis 11 days after operation and was repaired by abdominal split-thickness skin graft; the other flaps survived smoothly. The wound healing time in the recipient area was 10 to 42 days after operation, and the sutures in the donor area healed well. During the follow-up of 6 to 10 months, 8 patients underwent thinning and plastic surgery 6 months after operation because of bloating in the flap transplantation area, while the other patients had a good shape of the flap transplantation area, with no deep tissue infection such as osteomyelitis, with soft texture, good elasticity, no pain, and good blood circulation; all the donor areas were left with linear scars, normal blood circulation in the distal extremities, no limitation of knee joint motion or quadriceps muscle strength. At the last follow-up, the sensation function was restored in the flap transplantation area of the affected limb, including 14 cases of S1 grade and 45 cases of S2 grade; there was only one point of two-point discrimination; the curative effect evaluation of flap repair included excellent in 24 cases, good in 35 cases, and general in 3 cases. Conclusions: The anterolateral thigh perforator flap pedicled with oblique branch trunk of lateral circumflex femoral artery in the muscular septum has the advantages of relatively concealed donor area, large cutting width, and simple operation during surgery. It protects the donor area to the greatest extent while repairing skin and soft tissue defects in the extremities, and is a useful supplement to the classic anterolateral thigh perforator flap.

Toll-like receptor and matrix metalloproteinase single-nucleotide polymorphisms, haplotypes, and polygenic risk score differentiated between tuberculosis disease and infection

OBJECTIVES

The association of toll-like receptors (TLRs) and matrix metalloproteinases (MMPs) single-nucleotide polymorphisms (SNPs) among latent tuberculosis (TB) infection and active TB remained less studied.

METHODS

We recruited participants with TB disease (active TB) (n = 400) and TB infection (latent TB infection) (n = 203) in this study. We genotyped SNPs in TLR1, TLR2, TLR4, MMP1, MMP8, MMP9, MMP12, and tissue inhibitor of MMP2. Single-variant analysis and haplotype analysis were performed, and a polygenic risk score (PRS) was created.

RESULTS

We found that SNPs in TLR1 (rs5743580, rs5743551), TLR2 (rs3804100), and MMP8 (rs2508383) were associated with different TB disease status risks. TLR1 rs5743580 was associated with a higher risk of TB disease status in genotypic, recessive, and additive models. TLR2 rs3804100 polymorphisms demonstrated significant association with TB disease status in genotypic, dominant, and additive models. In the haplotype analysis, the TLR1 haplotype was associated with a higher risk of TB disease, and the MMP12 haplotype was associated with a lower risk of TB disease. A PRS using 3 SNPs was associated with a higher risk of TB disease.

CONCLUSION

This study revealed that SNP variants in TLR1, TLR2, and MMP8 differed among TB infection and disease. Haplotypes and PRS could potentially help predict TB disease status.

Immunogenicity and safety of two-dose SARS-CoV-2 vaccination via different platforms in kidney transplantation recipients

After kidney transplantation, patients exhibit a poor response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. However, the efficacy and adverse effects of vaccines based on different platforms in these patients remain unclear. We prospectively analyzed both anti-spike protein antibody and cellular responses 1 month after the first and second doses of SARS-CoV-2 vaccines in 171 kidney transplant patients. Four vaccines, including one viral vector (ChAdOx1 nCov-19, n = 30), two mRNA (mRNA1273, n = 81 and BNT162b2, n = 38), and one protein subunit (MVC-COV1901, n = 22) vaccines were administered. Among the four vaccines, mRNA1273 elicited the strongest humoral response and induced the highest interferon-γ levels in patients with a positive cellular response against the spike protein. Antiproliferative agents were negatively associated with both the antibody and cellular responses. A transient elevation in creatinine levels was noted in approximately half of the patients after the first dose of mRNA1273 or ChadOx1, and only one of them presented with borderline cellular rejection without definite causality to vaccination. In conclusion, mRNA1273 had better immunogenicity than the other vaccines. Further, renal function needs to be carefully monitored after vaccination, and vaccination strategies should be tailored according to the transplant status and vaccine characteristics.

[Construction of a risk assessment indicator system for re-establishment of imported malaria]

OBJECTIVE

To create a risk assessment indicator system for re-establishment of imported malaria.

METHODS

The risk assessment indicator system for re-establishment of imported malaria was preliminarily constructed through literature review and thematic discussions. A total of 26 malaria control experts were selected to carry out a two-round Delphi consultation of the indicator system. The active coefficient, authority coefficient and coordination coefficient of the experts and the coefficient of variation on each indicator were calculated for indicator screening and the weight of each indicator was calculated. The reliability of the indicator system was evaluated using Cronbach's coefficient α, and the content validity of the indicator system was evaluated using the authority coefficient of the expert, while the structural validity of the indicator system was evaluated using Kaiser-Meyer-Olkin (KMO) test and factor analysis.

RESULTS

Two rounds of Delphi expert consultations were completed by 23 malaria control experts, and a risk assessment indicator system for re-establishment of imported malaria was constructed, including 3 primary indicators, 7 secondary indicators, and 21 tertiary indicators. The active coefficient (100.00% vs. 88.46%; P < 0.01) and coordination coefficient of the expert (0.372 vs. 0.286; P < 0.01) were significantly greater in the second round of the Delphi expert consultation than in the first round. After the second round of the Delphi expert consultation, the authority coefficient of the experts ranged from 0.757 to 0.930 on each indicator, and the coefficients of variation were 0.098 to 0.136, 0.112 to 0.276 and 0.139 to 0.335 for the primary, secondary and tertiary indicators, respectively. The overall Cronbach's coefficient α of the indicator system was 0.941, and there were significant differences in the KMO values for primary (KMO value = 0.523; χ² = 18.192, P < 0.05), secondary (KMO value = 0.694, χ² = 51.499, P < 0.01) and tertiary indicators (KMO value = 0.519; χ² = 477.638, P < 0.01), while the cumulative contribution rate of six principal components in the tertiary indicators was 84.23%. The normalized weights of three primary indicators of the source of infection, transmission condition and control capability were 0.337, 0.333 and 0.329, and the three secondary indicators with the greatest normalized weights included the number of imported cases and malaria parasite species (0.160), introduction of imported cases in China and medical care seeking (0.152), vector species and density (0.152), while the five tertiary indicators with the greatest normalized weights included the malaria parasite species of imported cases (0.065), vector populations (0.064), and the time interval from onset to medical care seeking (0.059), number of imported cases (0.056), and the time interval from medical care seeking to definitive diagnosis (0.055).

CONCLUSIONS

A risk assessment indicator system for re-establishment of imported malaria is successfully created, which provides insights into the assessment of the risk of re-establishment of imported malaria and management of key high-risk factors in malaria-eliminated areas.

Multicenter Surveillance of Capsular Serotypes, Virulence Genes, and Antimicrobial Susceptibilities of Klebsiella pneumoniae Causing Bacteremia in Taiwan, 2017–2019

We conducted a longitudinal epidemiological surveillance of hypervirulent Klebsiella pneumoniae (hvKP) in Taiwan. Bacteremic KP isolates collected from 16 hospitals in Taiwan between 2017 and 2019 were collected, and the virulent serotypes (K1, K2, K20, K54, and K57), antimicrobial susceptibilities, and virulence genes of these isolates were investigated. During the 3-year period, 1,310 bacteremic KP isolates were collected, of which 27.5% belonged to virulent serotypes, including K1 (n = 162), K2 (n = 74), K57 (n = 56), K54 (n = 41), and K20 (n = 27). K1 was the most prevalent capsular serotype, with an annual prevalence of 11–15%, and was equally distributed across the four geographic areas. The prevalence of K2 declined significantly in 2019. According to wzi-K typing results, 87% of K1 isolates were classified as wzi-1. Among K2 isolates, wzi-72 (55.4%) and wzi-2 (41.9%) were the most common, whereas wzi-206 was the most prevalent (48.2%) among K57 isolates, followed by wzi-77 (25.0%). Wzi-115 accounted for 85.4% of the K54 isolates, whereas wzi-95 accounted for 92.6% of K20 isolates. rmpA was present in 99.4% of K1, 98.6% of K2, 89.3% of K57, 78.0% of K54, and 84.0% of K20 isolates. rmpA2 was present in 100% of K1 and 98.6% of K2 isolates but was only present in 64.3% of K57, 58.5% of K54, and 74.1% of K20 isolates. K1 remains the dominant hvKP serotype and is associated with most virulence genes in Taiwan. Further studies are required to elucidate the significance of other virulent serotypes.

Clinical characteristics of bacteremia caused by Haemophilus and Aggregatibacter species and antimicrobial susceptibilities of the isolates

BACKGROUND/PURPOSE

This study aimed to investigate the clinical characteristics and outcomes of bacteremia caused by Haemophilus and Aggregatibacter species in patients who were treated at a medical center between 2006 and 2018.

METHODS

Haemophilus and Aggregatibacter isolates were identified up to the species level using Bruker Biotyper MALDI-TOF analysis and ancillary 16S rRNA gene sequencing analysis (in case of ambiguity). Clinical characteristics and outcomes of patients with bacteremia caused by these organisms were evaluated.

RESULTS

Sixty-five Haemophilus and Aggregatibacter species isolates causing bacteremia were identified from nonduplicated patients, including 51 (78.5%) Haemophilus influenzae, 6 (9.2%) Haemophilus parainfluenzae, 1 (1.5%) Haemophilus haemolyticus, 3 (4.6%) A. aphrophilus, and 4 (6.2%) A. segnis. Hospital mortality was observed in 18 (28.1%) of 64 patients with bacteremia caused by Haemophilus (n = 57) and Aggregatibacter species (n = 7). The majority of patients with bacteremia had community-acquired disease with low severity. The average Sequential Organ Failure Assessment (SOFA) score was low (4.4 ± 4.7). But, a higher SOFA score (adjusted odds ratio 2.5, 95% confidence interval 1.22-5.12; P = 0.01) was an independent factor predicting poor 7-day clinical outcomes in patients with community-acquired H. influenzae bacteremia (n = 39).

CONCLUSIONS

The overall hospital mortality of 28.1% was observed among patients with bacteremia due to Haemophilus and Aggregatibacter species. A higher SOFA score was and independent predictor of poor 7-day clinical outcomes in patients with community-acquired H. influenzae bacteremia.

Comparison of Etest and broth microdilution for evaluating the susceptibility of Staphylococcus aureus and Streptococcus pneumoniae to ceftaroline and of carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa to ceftazidime/avibactam

OBJECTIVES

Decreased susceptibility to ceftazidime/avibactam (CZA) and ceftaroline (CPT) has been reported during antimicrobial resistance surveillance and therapy. Conventional laboratories are unable to provide timely susceptibility testing for CZA and CPT because these antimicrobial agents are not incorporated in automated susceptibility testing systems.

METHODS

We evaluated Etest and the Sensititre broth microdilution (BMD) method for testing CZA against carbapenem-resistant Gram-negative bacilli and CPT against important Gram-positive cocci bloodstream isolates. Genotypes of carbapenemases in Enterobacterales were also determined using the Xpert® Carba-R assay.

RESULTS

Etest showed ≥90% agreement with Sensititre BMD for carbapenem-resistant Klebsiella pneumoniae (CRKP) (n = 187), carbapenem-resistant Escherichia coli (CREC) (n = 28) and Streptococcus pneumoniae (n = 35); however, the very major error rate exceeded 3%. Agreement between Etest and Sensititre BMD was <90% for carbapenem-resistant Pseudomonas aeruginosa (CRPA) (n = 81), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 92) and methicillin-resistant S. aureus (MRSA) (n = 170). Both agents remained potent with a high susceptibility rate by Sensititre BMD as follows: CZA against CRKP (95.0%), CREC (89.3%) and CRPA (84.5%); and CPT against MSSA (100.0%), MRSA (95.3%) and S. pneumoniae (94.3%). CZA was active against blaKPC-carrying CRKP (98.5% susceptible), and resistance in the majority of CZA-resistant Enterobacterales isolates (6 of 10 CRKP and 2 of 3 CREC) was due to the presence of a metallo-β-lactamase gene.

CONCLUSION

Our results suggest that interpretation of susceptibility results obtained by Etest for both agents should be undertaken cautiously and remains challenging.

Two new black fly species of the Simulium ( Simulium) rufibasis subgroup (Diptera: Simuliidae) from Taiwan

Simulium ( Simulium) rufibasis Brunetti originally described from India was once considered a geographic generalist widely distributed in the Oriental Region. In this study, the species previously regarded as S. (S.) rufibasis in Taiwan was morphologically re-evaluated and found to be distinguished in the male and pupa from true S. (S.) rufibasis from India. This new species is described as S. ( S.) hehuanense sp. nov. based on a female, a male and their pupal exuviae in Taiwan. This new species is placed in the S. rufibasis subgroup of the S. tuberosum species-group, and is similar to S. (S.) yamatoense Takaoka, Adler & Fukuda from Japan and Korea, but it is barely distinguished by the slenderer forebasitarsi of the female and male. Another new, related species, S. (S.) xiulinense sp. nov., is described based on a male and its pupal exuviae. This new species is distinguished from S. (S.) hehuanense sp. nov. by the number of male upper-eye (large) facets in 20 or 21 vertical columns and 22 horizontal rows (19 vertical columns and 19 horizontal rows in the latter species), and presence of a pair of dorsolateral shiny spots on male abdominal segment 5 (absence in the latter species). Both new species inhabit streams at high elevations (ca, 2,600 m). They differ from S. (S.) sp. (probably S. (S.) arisanum Shiraki) from Taiwan, of the same subgroup, which breeds in streams at low elevations (433-685 m), by the pupal head and thorax covered with tubercles (bare in the latter species).

High rates of misidentification of uncommon Candida species causing bloodstream infections using conventional phenotypic methods

BACKGROUND

Candidemia caused by uncommon Candida species is increasing and misidentification may compromise optimal antifungal therapy. This multicenter study aimed to evaluate the accuracy of species-level identification of uncommon Candida.

METHODS

Uncommon causative species of candidemia identified in routine laboratories using CHROMagar, API-32C and VITEK-2 Yeast ID system were collected from July 2011 to June 2014. These isolates were further identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system and sequencing of the internal transcribed spacer and 28S rRNA gene. Susceptibility of the isolates was determined.

RESULTS

Of 85 isolates evaluated, Candida guilliermondii (n = 36) was the most common, followed by Candid sake (n = 7) and Candida famata (n = 4). Using DNA-sequencing analysis as standard, none of C. sake and C. famata was correct, while VITEK MS correctly identified 10 of the 11 isolates. With the exclusion of one unspecified Candida by DNA-sequencing methods, the accuracy of conventional methods and VITEK MS was 64.3% and 86.9%, respectively (p = 0.001). Eight isolates were confirmed to be yeasts other than Candida. Compared with other Candida species, C. guilliermondii showed elevated minimal inhibitory concentration of echinocandins.

CONCLUSION

Misidentification of uncommon Candida species was common using the conventional methods, especially for C. sake and C. famata. MALDI-TOF MS assisted by DNA-sequencing methods should be considered.

Polypharmacy is a risk factor for hospital admission due to a fall: evidence from the English Longitudinal Study of Ageing

Background

Falls amongst older people are common; however, around 40% of falls could be preventable. Medications are known to increase the risk of falls in older adults. The debate about reducing the number of prescribed medications remains controversial, and more evidence is needed to understand the relationship between polypharmacy and fall-related hospital admissions. We examined the effect of polypharmacy on hospitalization due to a fall, using a large nationally representative sample of older adults.

Methods

Data from the English Longitudinal Study of Ageing (ELSA) were used. We included 6220 participants aged 50+ with valid data collected between 2012 and 2018.The main outcome measure was hospital admission due to a fall. Polypharmacy -the number of long-term prescription drugs- was the main exposure coded as: no medications, 1–4 medications, 5–9 medications (polypharmacy) and 10+ medications (heightened polypharmacy). Competing-risk regression analysis was used (with death as a potential competing risk), adjusted for common confounders, including multi-morbidity and fall risk-increasing drugs.

Results

The prevalence of people admitted to hospital due to a fall increased according to the number of medications taken, from 1.5% of falls for people reporting no medications, to 4.7% of falls among those taking 1–4 medications, 7.9% of falls among those with polypharmacy and 14.8% among those reporting heightened polypharmacy. Fully adjusted SHRs for hospitalization due to a fall among people who reported taking 1–4 medications, polypharmacy and heightened polypharmacy were 1.79 (1.18; 2.71), 1.75 (1.04; 2.95), and 3.19 (1.61; 6.32) respectively, compared with people who were not taking medications.

Conclusions

The risk of hospitalization due to a fall increased with polypharmacy. It is suggested that prescriptions in older people should be revised on a regular basis, and that the number of medications prescribed be kept to a minimum, in order to reduce the risk of fall-related hospital admissions.

Klebsiella pneumoniae bacteremia revisited: Comparison between 2007 and 2017 prospective cohorts at a medical center in Taiwan

BACKGROUND

Community onset K. pneumoniae bacteremia (KPB) is a major problem in Taiwan for decades. We aimed to revisit the role of virulent genotype K1/K2 and possible predisposing factors, compared to our published 2007 cohort.

METHODS

All adult patients with monomicrobial KPB during 2017 at a medical center in Taiwan were prospectively enrolled. We genotyped the major K types of K. pneumoniae strains, and analyzed the role of prior use of antibiotic or proton pump inhibitor (PPI).

RESULTS

A total of 213 cases were enrolled. Compared to our previous 2007 study (n = 231), there was a higher percentage of patients with community onset bacteremia (75% vs. 60%, p = 0.003). The overall mortality rate was lower in 2017 (23% vs. 32%, p = 0.02), while the rates of antimicrobial resistance (all classes) were higher in 2017. There were 40 cases of liver abscesses in 2017 (19%), with an overall mortality rate of 7.5%. The prevalence of K1 was similar (16% in 2017 vs. 19% in 2007), but the prevalence of K2 decreased significantly (7% in 2017 vs. 17% in 2007, p = 0.001). After excluding 39 cases without data of recent medication use, 48 of 174 (28%) of patients had received a PPI within 90 days. Patients with recent PPI use had more complicated underlying illnesses, higher antimicrobial resistance, and higher in-hospital mortality, but was negatively associated with liver abscess (4% vs. 24%, p = 0.002). Of patients with community-acquired bacteremia, 51% used antibiotics within 90 days. After excluding 37 patients received antibiotics within 14 days before the detection of bacteremia, patient with antibiotic use within 15-90 days had higher Pittsburgh bacteremia scores (4.5 vs. 2.7, p = 0.04), creatinine levels, and frequency of recent surgery, but was not associated with liver abscess (21% vs. 31%, p = 0.33).

DISCUSSION

In summary, after a decade, community onset KPB is still prevalent (1.3 case per 1000 emergency department visit). K1 remains to be the dominant genotype. The association of prior ampicillin/amoxicillin or PPIs use for liver abscess is not confirmed.

Molecular Evidence for Intra- and Inter-Farm Spread of Porcine mcr-1-Carrying Escherichia coli in Taiwan

From January 2013 to December 2018, 90 Escherichia coli isolates were collected from 90 sick pigs on 58 farms in seven cities in Taiwan. The minimum inhibitory concentrations (MICs) of the isolates to 14 antimicrobial agents were determined on the VITEK 2 system (bioMérieux, Marcy-l’Etoile, France), and the resistance to colistin was assessed via the reference broth microdilution (BMD) method. The mobilized colistin resistance genes (mcr) were determined for the colistin-resistant isolates, which displayed BMD MICs ≥ 4 mg/L. Genotypes of the mcr-positive E. coli isolates were determined by multilocus sequence typing, arbitrarily primed polymerase chain reaction (PCR), and pulsed-field gel electrophoresis. All of the isolates were tested for susceptibility to carbapenems. Fifty isolates (55.6%) were resistant to colistin, 39 of which (78%) were positive for the mcr-1 gene. E. coli isolates harboring mcr-1 were most frequent in 2017 (15/18, 83.3%), followed by 2018 (13/23, 56.5%), 2015 (7/21, 33.3%), and 2016 (3/24, 12.5%). A total of 18 sequence types (STs) were identified among the 39 porcine mcr-1-carrying E. coli isolates; 13 were ST2521 (33.3%) isolated in 2017 and 2018. Five genotypes (clones) were identified, and the same genotypes were in sick pigs on the same farm and different farms. This suggests intra- and inter-farm spread of porcine mcr-1-carrying E. coli. The results presented here indicate high colistin resistance and wide mcr-1 E. coli prevalence among the sick pigs sampled in 2015–2018 in different regions of Taiwan.

[Clinical characteristics of 83 patients with thrombotic thrombocytopenic purpura]

Objective: To analyze the clinical characteristics, treatment and prognosis of patients with thrombotic thrombocytopenic purpura (TTP) . Methods: 83 patients with TTP from May 1998 to May 2019 were analyzed retrospectively. Results: Among the 83 patients, there were 27 males and 56 females, with a median age of 39 (10-68) years. 41 cases (49.4%) showed pentalogy syndrome and 79 cases (95.2%) showed triad syndrome. 78.0% (46/59) of the patients had a PLASMIC score of 6 or higher. TTP gene mutations was detected in 5 of 10 patients. The activity of von Willebrand factor-cleaving protease (ADAMTS13) , which was detected in 10 patients before plasma exchange (PEX) , was less than 10% in 9 patients. 83 patients were treated with PEX/plasma infusion and glucocorticoid, 35 of which were treated combined with rituximab and/or immunosuppressant. The median follow-up was 34 (1-167) months, the effective rate was 81.9%, the remission rate was 63.9%, the relapse rate was (35.7 ±7.1) %, and the 3-year overall survival (OS) rate was (78.6 ±4.6) %. The effective rate (72.9%vs 94.3%, P=0.019) and OS rate[ (63.8±7.5) %vs (94.3±3.9) %, χ(2)=8.450, P=0.004] in the group treated with PEX/PI and glucocorticoid alone were lower than those in the group treated combined with rituximab and/or immunosuppressant. COX multivariate analysis showed that age (HR=1.111, 95%CI 1.044-1.184, P=0.001) and alanine transaminase (ALT) /aspartate aminotransferase (AST) (HR=1.353, 95%CI 1.072-1.708, P=0.011) were independent risk factors for OS. Conclusion: Most patients with TTP have triad syndrome, accompanied by a decrease in ADAMTS13 activity. Plasma infusion and glucocorticoid combined with rituximab, immunosuppressive therapy could improve overall survival. The prognosis of patients with older age and high ALT/AST ratio is poor.

[Eltrombopag for the treatment of primary immune thrombocytopenia in 23 pediatric patients]

目的

评估艾曲泊帕治疗儿童原发免疫性血小板减少症（ITP）的疗效和不良反应。

方法

回顾性分析2015年5月至2019年3月接受艾曲泊帕治疗的23例儿童ITP患者临床资料。

结果

23例患者中，男11例，女12例，中位年龄11（2~17）岁。新诊断ITP 4例（17.39%），持续性ITP 8例（34.78%），慢性ITP 11例（47.83%）。艾曲泊帕中位起始剂量为25.0（12.5~50.0）mg/d。基线中位血小板计数为14（2~82）×10⁹/L，治疗后第2周（23例）、第4周（23例）、第3个月（16例）、第6个月（11例）的中位血小板计数分别为40（4~170）×10⁹/L、20（4~130）×10⁹/L、60（4~110）×10⁹/L、70（18~160）×10⁹/L，均高于基线水平（z=-3.440，P=0.001；z=-1.964，P=0.049；z=-4.339，P<0.001；z=-5.794，P<0.001）。7例（30.43%）患者的起效时间≤7 d，10例（43.48%）患者的起效时间≤2周，总有效率为60.87%（14/23）。<6岁（6例）、6~12岁（10例）、13~17岁（7例）组的总有效率分别为33.33%（2/6）、60.00%（6/10）、85.71%（6/7），组间比较差异均无统计学意义（P>0.05）。23例患者基线WHO出血评分0、1、2级分别有4、12、7例，治疗后分别为13、7、3例，出血症状得到明显改善（χ²=7.558，P=0.006）。治疗过程中发生转氨酶、胆红素增高各4例，轻度恶心、呕吐及头晕各1例，对治疗均未造成影响。

结论

艾曲泊帕作为二线用药治疗儿童ITP疗效及耐受性均较好。

[The incidence and risk factors for thrombosis in primary immune thrombocytopenia]

目的

探讨原发免疫性血小板减少症（ITP）患者血栓发生情况及相关危险因素。

方法

对2005年12月至2017年12月在中国医学科学院血液病医院血栓止血中心住院治疗的3 225例ITP患者进行回顾性分析。

结果

共46例患者（1.43%）发生血栓事件，中位发病年龄为54（26~83）岁，成人患者中>40岁人群血栓发生率明显高于40岁以下人群[3.37%（40/1 187）对0.58%（6/1 030），P=0.000]。男、女性患者血栓发生率差异无统计学意义[1.53%（20/1309）对1.36%（26/1 916），P=0.187]。动脉血栓的发生率高于静脉血栓[1.12%（36/3 225）对0.22%（7/3 225），P=0.000]。82.61%（38/46例）患者发生血栓时PLT<100×10⁹/L。吸烟、高血压病、糖尿病及脾切除是ITP患者发生血栓的危险因素（P值分别为0.232、0.531）；糖皮质激素、TPO治疗患者治疗在有无血栓事件的两组间比较差异无统计学意义（P值分别为0.064、0.075、0.531）。

结论

对于中国人群，ITP疾病本身可能也是一种可伴发血栓的免疫性疾病，即使血小板水平低下仍可发生血栓事件；且具有明显的年龄分布特点；吸烟史、高血压病、糖尿病史及脾切除是发生血栓的危险因素。

[Prognostic analysis of colon and rectal neuroendocrine neoplasm in different stages]

Objective: To explore the survival difference of patients with colon and rectal neuroendocrine neoplasm (NEN) at different stages. Methods: We identified 8 679 patients with colorectal NEN diagnosed between 1988 and 2014 from the Surveillance, Epidemiology, and End Results (SEER) registry, including 5 437 rectal NEN and 3 242 colon NEN ( 1 681 cecum NEN ). Survival curve was drawn by Kaplan-Meier method. Prognostic factors were analyzed by univariate analysis and multivariate Cox regression model. Results: The ratio of male patients with colon and rectal NEN was similar to female (P=0.095). Rectal NEN patients were younger (P<0.001), more highly differentiated (P<0.001), and with earlier stage (P<0.001). Survival analysis showed that the survival of rectal NEN was superior to that of colon NEN, with 10-year tumor-specific survival rates of 86.8% and 44.8% respectively (P<0.001). Multivariate Cox analysis showed that age, gender, marital status, primary tumor site, grade, stage and surgery were independent prognostic factors of colorectal NEN (all P<0.01). The most important factor was stage (HR=3.531), followed by differentiation grade (HR=1.856). Stratified analysis displayed that the survival of rectal NEN in stage Ⅰ, Ⅱ and Ⅳ were better than those of corresponding stage of colon NEN (all P<0.05), but worse in stage Ⅲ (P=0.012). While the survival of rectal NEN were significantly better than those of colon NEN within all stages after excluding 1681 cases of cecal NEN (all P<0.05). Among the patients with well-differentiated NEN, the survival of rectal NEN in stage Ⅰ, Ⅲ and Ⅳ were better than those of corresponding stage of colon NEN (all P<0.05) while there was no significant difference in stage Ⅱ(P=0.169). For poor-differentiated NEN, only the survival of rectal NEN patients in stage Ⅳ (P=0.001) was significant longer than those of colon NEN, while there was no significant difference in stage Ⅰ, Ⅱ and Ⅲ (stage Ⅰ: P=0.760; stage Ⅱ: P=0.181; stage Ⅲ: P=0.313). Conclusions: The survival of NEN patients in colon and rectum is different. Cecum NEN should be considered as a separated tumor for prognostic analysis due to its special clinicopathologic characteristics.

[Immune tolerance induction in a case of hemophilia B with inhibitor with prothrombin complex concentrate and rituximab]

目的

探讨血友病B伴抑制物的免疫耐受诱导（ITI）治疗，提高血友病B伴抑制物的诊疗水平。

方法

应用基于APTT标准曲线的一期法测定重型血友病B患者凝血因子Ⅸ（FⅨ）活性，应用Bethesda法进行FⅨ抑制物定量测定；利用凝血酶原复合物（PCC）进行ITI并联合利妥昔单抗清除患者抑制物。

结果

患儿既往PCC暴露日为20 d，抑制物滴度峰值为56 BU/ml。在2015年11月患儿抑制物滴度降至10.4 BU/ml时开始ITI治疗，单用PCC一段时间无效，给予PCC联合利妥昔单抗治疗，17个月后成功清除患者体内FⅨ抑制物，未发生过敏反应及肾病综合征等并发症。ITI过程中患者年化出血率有所改善。

结论

该患者是国内首例报道的采用ITI联合利妥昔单抗成功治疗血友病B伴抑制物的病例。PCC联合利妥昔单抗ITI治疗是目前有希望清除血友病B抑制物的方法。

In vitro activities of cefiderocol, ceftolozane/tazobactam, ceftazidime/avibactam and other comparative drugs against imipenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, and Stenotrophomonas maltophilia, all associated with bloodstream infections in Taiwan

Objectives

We investigated the in vitro activities of cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam and other related drugs against imipenem-resistant Pseudomonas aeruginosa, imipenem-resistant Acinetobacter baumannii and Stenotrophomonas maltophilia isolates.

Methods

Non-duplicated bacteraemia isolates (n = 300) of imipenem-resistant P. aeruginosa (n = 100), imipenem-resistant A. baumannii (n = 100) and S. maltophilia (n = 100) were evaluated. Imipenem-resistant P. aeruginosa and imipenem-resistant A. baumannii isolates were defined as isolates exhibiting imipenem MIC ≥8 mg/L, as determined using the VITEK 2 system. The MICs of 11 other antimicrobial agents for the isolates were determined by the broth microdilution method. Iron-depleted CAMHB was used to determine the MICs of cefiderocol.

Results

The rates of colistin resistance of imipenem-resistant P. aeruginosa and imipenem-resistant A. baumannii were 5% and 10%, respectively. The MIC90 values of cefiderocol, ceftolozane/tazobactam, ceftazidime/avibactam, tigecycline and colistin were as follows: imipenem-resistant P. aeruginosa: 1, 4, 16, >4 and 2 mg/L; imipenem-resistant A. baumannii: 8, >64, >64, 4 and 2 mg/L; and S. maltophilia: 0.25, >64, >64, 2 and >8 mg/L, respectively. For imipenem-resistant A. baumannii isolates, the MICs of cefiderocol, ceftolozane/tazobactam and ceftazidime/avibactam were ≤4 mg/L for 88%, 8% and 1% of the isolates, respectively. Cefiderocol MICs were ≤4 mg/L for the five colistin-resistant imipenem-resistant P. aeruginosa isolates and 70% of the 10 colistin-resistant imipenem-resistant A. baumannii isolates.

Conclusions

Cefiderocol exhibited more potent in vitro activity than ceftolozane/tazobactam and ceftazidime/avibactam against imipenem-resistant P. aeruginosa, imipenem-resistant A. baumannii and S. maltophilia isolates.

Clinical characteristics of Candida tropicalis fungaemia with reduced triazole susceptibility in Taiwan: a multicentre study

Candida tropicalis is the second most common Candida species causing fungaemia in Taiwan, and decreased susceptibility to fluconazole has been reported. This study analysed the clinical characteristics of adult patients with C. tropicalis fungaemia and the antifungal susceptibilities of isolates at five tertiary hospitals in Taiwan (1 July 2011 to 30 June 2014). A standardised case record form was used retrospectively to collect demographic, clinical and microbiological characteristics, antifungal treatment and outcomes. MICs of non-duplicate isolates were determined using Sensititre^TM YeastOne^TM and were interpreted using cut-off values recommended by the CLSI. A total 248 patients were diagnosed over the study period; 30-day crude mortality was 52.0%. Multivariate analysis showed that high Charlson comorbidity index ≥4 (OR = 2.09, 95% CI 1.22-3.59; P = 0.008), neutropenia (OR = 4.61, 95% CI 1.42-15.00; P = 0.011) and treatment with an azole-based regimen (OR = 0.39, 95% CI 0.17-0.90; P = 0.028) were significantly associated with 30-day mortality. A total of 33.9% of isolates were non-susceptible to fluconazole (MIC₅₀, 2 mg/L; MIC₉₀, 16 mg/L; MIC range, 0.25 to >256 mg/L), whilst 56.9% to voriconazole (MIC₅₀, 0.25 mg/L; MIC₉₀, 1 mg/L; MIC range, 0.015 to >8 mg/L) according to CLSI clinical breakpoints. There was no significant correlation between overall mortality and MICs of fluconazole or voriconazole. This study showed high mortality in patients with C. tropicalis fungaemia, and azole-based antifungal treatment could improve outcomes regardless of fluconazole MICs of infecting isolates compared with patients without any treatment within 48 h.

Characterization of rifampin-resistant Staphylococcus aureus nasal carriage in patients receiving rifampin-containing regimens for tuberculosis

Objectives

This study investigated molecular characteristics of rifampin (RIF)-resistant (RIF-R) Staphylococcus aureus isolates recovered from patients receiving RIF-containing regimens for tuberculosis (TB).

Patients and methods

Patients with TB who received RIF-containing regimens from November 2009 to May 2011 at a medical center were enrolled. Nasal swabs for S. aureus culture were obtained at the time of enrollment, and then every two months until two months after RIF treatment had been completed. Genetic relatedness of the isolates was determined using pulsed-field gel electrophoresis, multilocus sequence typing, and gene typing of spa and SCCmec. The presence of RIF resistance-associated mutations in rpoB, and fusidic acid resistance genes fusB and fusC in the S. aureus isolates were analyzed.

Results

Among the 200 patients enrolled in this study, 152 completed follow-ups during treatment, and 114 completed two months of follow-up after discontinuing use of RIF. At enrollment, ten patients (5%) had nasal colonization with S. aureus, namely eight with methicillin-susceptible S. aureus (MSSA), and two with methicillin-resistant S. aureus (MRSA, ST59-SCCmecIV-RIF-susceptible). All these patients were decolonized after RIF usage. Two patients with MSSA colonization at enrollment showed recolonization with genetically unrelated MSSA strains two months after completion of RIF treatment. There were five ST45-SCCmecV_T-RIF-R strains from two patients isolated during RIF exposure. Sequencing of rpoB in the RIF-R S. aureus isolates revealed different mutation sites between the MSSA and MRSA isolates.

Conclusion

RIF-R S. aureus strains are more likely to result in persistent nasal carriage in TB patients receiving RIF treatment. Monitoring of emergence and possible dissemination of the MRSA ST45 strains among TB patients treated with RIF in Taiwan is warranted.

Antimicrobial susceptibilities and molecular typing of neisseria gonorrhoeae isolates at a medical centre in Taiwan, 2001-2013 with an emphasis on high rate of azithromycin resistance among the isolates

A high prevalence of gonococcal resistance to various antimicrobials and Neisseria gonorrhoeae isolates exhibiting resistance to extended-spectrum cephalosporins have been reported in the past few decades. A total of 226 N. gonorrhoeae isolates obtained from the National Taiwan University Hospital from 2001 to 2013 were evaluated. The minimum inhibitory concentrations (MICs) of the isolates to antimicrobials were determined by the agar dilution method and interpreted using the 2017 clinical breakpoints or epidemiological cut-off values recommended by the Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST). The genetic relatedness of these isolates was determined by multilocus sequence typing. None of the isolates was resistant to ceftriaxone and cefotaxime, and the resistance rates to cefixime, spectinomycin, cefpodoxime, ciprofloxacin, and penicillin were 0.4%, 0.4%, 13.3%, 91.6%, and 87.6%, respectively. The rate of isolates resistant to azithromycin was 14.6% (EUCAST criteria), which is higher than in previous surveillance studies. A total of 57 sequence types (ST) were identified, and ST1901, ST7365, and ST1927 prevailed. Isolates of ST8143 emerged after 2011. ST1901 isolates had relatively higher MIC values for ceftriaxone and azithromycin than those of the other STs. In conclusion, ceftriaxone remains an effective drug of choice for gonorrhoeal management in Taiwan. High rates of azithromycin resistance among N. gonorrhoeae isolates were found. The circulating ST1901 strains with high MIC values for ceftriaxone and azithromycin and the emerging ST8143 strains were alarming.

[Circulating tumor DNA and targeted therapy in colorectal cancer]

The detection of circulating tumor DNA is a quick, low cost and reliable approach of liquid biopsy of cancer. It has a wide range of applications for tumor screening because of its noninvasive, convenient and highly repeatable features. In terms of the targeted therapy in patients with colorectal cancer, serial monitoring of circulating tumor DNA, especially for the specific genetic alterations, can be used for prognosis, monitoring resistance, evaluation of therapeutic effects and screening combined targeted therapy. Therefore, it will guide more precise treatment of colorectal cancer.

Emergence of multidrug-resistant sequence type 45 strains among mecA-positive borderline oxacillin-resistant Staphylococcus aureus causing bacteraemia in a medical centre in Taiwan

Clinical data related to bacteraemia caused by mecA-positive borderline oxacillin-resistant Staphylococcus aureus (BORSA) isolates [minimum inhibitory concentrations (MICs) of 0.5-4 mg/L] are limited. Patients aged ≥15 years with bacteraemia due to BORSA who were admitted to the emergency department of a Taiwanese tertiary hospital between January 2001 and December 2015 were evaluated. Clinical characteristics of patients with bacteraemia caused by BORSA, methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) were compared. MICs of 12 antibiotics were determined by agar dilution. Genetic characteristics of 64 available BORSA isolates were analysed by detection of the SCCmec gene, the mecA promoter region sequence and multilocus sequence typing (MLST). Pulsed-field gel electrophoresis (PFGE) was performed to identify the clonality of the emerging ST isolates. The quinolone resistance genes were analysed for the emerging ciprofloxacin-resistant ST45 clone isolates. Among the 65 BORSA bacteraemic patients, in-hospital mortality was 24.6%, significantly lower than that of MRSA patients (38.5%) (P = 0.03). Underlying conditions were similar between BORSA and MRSA patients, but with less dialysis in the former (P = 0.01). Multivariate analysis revealed that septic shock [odds ratio (OR) = 15.95] and bacteraemia originating from lower respiratory tract infection (OR = 5.78) were two independent risk factors for 30-day mortality. The ST45 clone with high-level ciprofloxacin resistance (MICs of 8-128 mg/L) replaced ST59 as the predominant clone since 2012, although no major clustering was detected. In conclusion, the emerging multidrug-resistant ST45 clone has replaced ST59 as the most common among BORSA isolates.