Emergence and Persistent Dominance of SARS-CoV-2 Omicron BA.2.3.7 Variant, Taiwan.

Since April 2022, waves of SARS-CoV-2 Omicron variant cases have surfaced in Taiwan and spread throughout the island. Using high-throughput sequencing of the SARS-CoV-2 genome, we analyzed 2,405 PCR-positive swab samples from 2,339 persons and identified the Omicron BA.2.3.7 variant as a major lineage within recent community outbreaks in Taiwan.

National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.

Reference levels for glucose-6-phosphate dehydrogenase enzyme activity in infants 7-90 days old in Taiwan.

BACKGROUND: Nationwide newborn screening for glucose-6-phosphate dehydrogenase (G6PD) deficiency has been implemented in Taiwan since 1987 and the G6PD enzyme activity levels were applied for diagnosis confirmation. As the reference value of G6PD enzyme activity was not available for infants aged 7-90 days, this study was performed to determine the enzyme level in different genotypes. METHODS: Between January 1, 2016 and June 30, 2017, 410 term infants aged 7-90 days old visiting National Taiwan University Hospital Hsinchu branch were enrolled. The comparisons of G6PD enzyme activities among genotype groups were performed. RESULTS: G6PD enzyme activity was negatively correlated with age (R = -0.212, p = 0.01). For infants under 30 days of age, the G6PD enzyme activity levels were 1.4 ± 0.9 U/g Hb in hemizygotes (n = 76), 6.5 ± 2.0 U/g Hb in heterozygotes (n = 47), and 13.6 ± 3.7 U/g Hb in those without G6PD mutations (n = 70). Among infants more than 30 days old, G6PD enzyme activity levels were 0.9 ± 0.5 U/g Hb in hemizygotes (n = 46), 6.0 ± 2.7 U/g Hb in heterozygotes (n = 23), and 11.7 ± 3.4 U/g Hb in those without G6PD mutations (n = 148). G6PD levels differed significantly among the groups defined by genotypes. CONCLUSION: We determined G6PD enzyme activity levels in infants aged between 7 and 90 days in Taiwan. Completing the reference data and determining the cutoff values for different G6PD deficiency disease statuses will help pediatricians to make accurate diagnoses.

Pneumococcal vaccination and efficacy in patients with heterotaxy syndrome.

BackgroundPneumococcal vaccines, including pneumococcal polysaccharide vaccine (PPV) and pneumococcal conjugated vaccine (PCV), are crucial in preventing invasive pneumococcal diseases. We analyzed the pneumococcal vaccination rate, efficacy, and durability in patients with heterotaxy.MethodsAll patients with heterotaxy and CCHD who were followed up at our institution between 2010 and 2015 were included. Pneumococcal vaccine status and geometric mean concentration (GMC) of serotypes 6B, 14, 19F, and 23F were analyzed. Splenic function was considered abnormal when the percentage of IgM memory B cell was less than 1%.ResultsThe GMCs of the four serotypes did not differ significantly between patients with heterotaxy and those with CCHD; the GMCs were also not affected by abnormal splenic function. Most patients had GMCs >0.35 µg/ml (protection level) 4-5 years after either PPV or PCV injection; however, it may decay gradually in some serotypes. In addition, 21.4% of 42 patients with heterotaxy did not receive pneumococcal vaccine, and none completely adhered to the vaccine guidelines.ConclusionsVaccine efficacy was acceptable, even in patients with abnormal splenic function. In some patients, the durability of PPV and PCV decreased with time, highlighting the importance of booster doses. Vaccination rate in patients with heterotaxy is unsatisfactory.

Infectious complications in children with acute lymphoblastic leukemia treated with the Taiwan Pediatric Oncology Group protocol: A 16-year tertiary single-institution experience.

BACKGROUND: Infection is a major complication in pediatric patients with acute lymphoblastic leukemia during chemotherapy. In this study, the infection characteristics were determined and risk factors analyzed based on the Taiwan Pediatric Oncology Group (TPOG) acute lymphoblastic leukemia (ALL) protocol. PROCEDURE: We retrospectively reviewed fever events during chemotherapy in 252 patients treated during two consecutive clinical trials at a single institution between 1997 and 2012. Patients were classified as standard, high, and very high risk by treatment regimen according to the TPOG definitions. We analyzed the characteristics and risk factors for infection. RESULTS: Fever occurred in 219 patients (86.9%) with a mean of 2.74 episodes per person. The fever events comprised 64% febrile neutropenia, 39% clinically documented infections, and 44% microbiologically documented infections. The microbiologically documented infections were mostly noted during the induction phase and increased in very high risk patients (89 vs. 24% and 46% in standard-risk and high-risk patients, respectively). Younger age and higher risk (high-risk and very high risk groups) were risk factors for fever and microbiologic and bloodstream infections. Female gender and obesity were additive risk factors for urinary tract infection (odds ratios = 3.52 and 3.24, P < 0.001 and P = 0.004, respectively). CONCLUSIONS: Infections developed primarily during the induction phase, for which younger age and higher risk by treatment regimen were risk factors. Female gender and obesity were additive risk factors for urinary tract infection.

Risk of Respiratory Syncytial Virus Infection in Cyanotic Congenital Heart Disease in a Subtropical Area.

OBJECTIVE: To compare the risk of respiratory syncytial virus (RSV)-associated hospitalization and analyze the epidemiology of RSV infection in patients with cyanotic and acyanotic congenital heart disease (CHD), we analyzed the nationwide health insurance database from 2005-2010. STUDY DESIGN: This study included 1050 patients with cyanotic CHD and 7077 patients with acyanotic CHD. Patients with acyanotic CHD were further classified into hemodynamically significant (hs)-acyanotic and non-hs-acyanotic groups according to whether they underwent surgery or took at least 2 anticongestive medications. RESULTS: RSV-associated hospitalization was higher in the cyanotic group than in hs-acyanotic and non-hs-acyanotic groups both before 1 year of age (4.8% vs 2.1% vs 1.5%, P < .001) and between 1 and 2 years of age (0.9% vs 0.56% vs 0.14%, P = .003). The hospitalization duration, intensive care, ventilator support prevalence, hospitalization cost, and mortality rate were significantly higher in the cyanotic group than in the other 2 groups. Logistic regression revealed that cyanotic CHD was the most significant risk factor for the ventilator support and RSV-associated mortality. In both patients with cyanotic and acyanotic CHD, RSV-associated hospitalization rate was higher in patients aged younger than 1 year and in spring and autumn in Taiwan, a subtropical country. CONCLUSIONS: The results show that patients with cyanotic CHD have a higher risk of severe RSV infection than do those with acyanotic CHD. RSV prophylaxis is more important and may reduce costs more for patients with cyanotic CHD.

Low immunoglobulin M memory B-cell percentage in patients with heterotaxy syndrome correlates with the risk of severe bacterial infection.

BACKGROUND: Patients with heterotaxy syndrome, commonly associated with complex congenital heart disease (CHD), exhibit a higher risk of severe bacterial infection (SBI). We sought to define the change of a novel immunologic marker, the immunoglobulin M (IgM) memory B-cell percentage, and its association with SBI. METHODS: We enrolled 46 (M/F 29/17) heterotaxy syndrome patients (42 right atrial isomerism (RAI) and 4 left atrial isomerism (LAI)) aged > 1 y during the period 2010-2012 in a tertiary care center. We analyzed IgM(+)CD27(+) memory B-cell percentages. Patients with simple and complex CHD served as controls. RESULTS: The mean IgM memory B-cell percentages were the lowest in the heterotaxy syndrome group, compared with those in complex and simple CHD groups (1.8 ± 2.1 vs. 3.9 ± 3.2 vs. 5.1 ± 4.7, P < 0.001). In the heterotaxy syndrome group, 41.3% had low IgM memory B-cell percentages (<1% of B cells). Seven had a history of community-acquired SBI and 85.7% of these had low IgM memory B-cell percentages, which was the only significant factors related to community-acquired SBI (P = 0.028). CONCLUSION: The memory B cell and IgM memory B-cell percentages are low in patients with heterotaxy syndrome, and the presence of IgM memory B-cell percentage < 1% correlates with community-acquired SBI.

Transmission of acute infectious illness among cases of Kawasaki disease and their household members.

BACKGROUND/PURPOSE: Kawasaki disease (KD) is a disease of unknown cause and the causative agent is most likely to be infectious in nature. To investigate the household transmission pattern of infectious illness and etiology, we thus initiated a prospective case and household study. METHODS: We enrolled KD cases and their household members from February 2004 to September 2008. The KD cases and their household members accepted questionnaire-based interviews of the contact history, signs of infection, and symptoms to check whether clusters of infectious illness occurred. RESULTS: A total of 142 KD cases and 561 household members were enrolled. Among the 142 KD cases, 136 cases (96%) were typical KD, and six (4%) were atypical KD. Of the 561 household members, 17% were siblings, 46% were parents, 18% were grandparents, and the others were cousins or babysitters. Prior to the onset of their KD illness, 66% (94/142) KD cases had contact with ill household members. On the same day of the onset of KD cases' illness, 4% (6/142) KD cases had household members with illness. After KD cases' disease onset, 70% (100/142) KD cases had at least one other family member with illness. Overall, 61% (343/561) of all the household members had acute infectious illness during KD cases' acute stage, and 92% (130/142) of the families had clusters of infectious illness. CONCLUSION: A total of 66% KD cases had positive contact with ill household members prior to their disease onset and 92% of families had clusters of infectious illness, so KD is strongly associated with infections.

Severe bacterial infection in patients with heterotaxy syndrome.

OBJECTIVE: To determine the incidence of sepsis in patients with heterotaxy syndrome. STUDY DESIGN: From our institutional database, we identified patients with heterotaxy syndrome and other complex congenital heart disease (CHD) born between 2001 and 2011. Severe bacterial infection was defined as sepsis with positive culture result or infection with abscess formation. RESULTS: We enrolled 95 patients with heterotaxy syndrome (88 with right atrial isomerism and 7 with left atrial isomerism) and 142 patients with complex CHD. With 1026 person-years follow-up, the 5-year survival was 52% and 65.7% in heterotaxy and complex CHD groups, respectively (P = .239). Community-acquired severe bacterial infection occurred only in heterotaxy syndrome (13 episodes in 10 patients, 3 of whom had spleen noted at imaging study) with 2- and 5 years cumulative severe bacterial infection rate of 9.6% and 14.5%, respectively. The overall mortality rate of those with community-acquired severe bacterial infection was 31%. Pneumococcus and Citrobacter freundii were the most common pathogens. Nosocomial severe bacterial infection occurred in 33.3% of all patients and 12.5% of all procedures. The rates (0.59 and 0.52/100 hospitalization days in heterotaxy and complex CHD group) and the pathogens of nosocomial severe bacterial infection were similar between heterotaxy and complex CHD groups. CONCLUSIONS: Patients with heterotaxy syndrome are at high risk for community-acquired severe bacterial infection and also have high mortality rate whether the spleen is present or not. The risk of nosocomial severe bacterial infection seems similar to that of patients with other complex CHD.

Viral infections associated with Kawasaki disease.

BACKGROUND/PURPOSE: Kawasaki disease (KD) is a disease of unknown cause. To investigate the infectious etiology of Kawasaki disease, we initiated a prospective case-control study to investigate possible links between common viral infections and Kawasaki disease. METHODS: We enrolled 226 children with KD and 226 age- and sex-matched healthy children from February 2004 to March 2010. Throat and nasopharyngeal swabs were taken for both viral isolation and polymerase chain reaction (PCR) for various viruses. RESULTS: The mean age of the 226 KD cases was 2.07 years, and the male to female ratio was 1.43 (133 boys to 93 girls). Their mean fever duration was 7.5 days with a mean peak temperature of 39.7°C. In addition to the typical symptoms of fever, neck lymphadenopathy, lip fissure and/or strawberry tongue, skin rash, nonpurulent bulbar conjunctivitis, palm/sole erythema, and induration followed by periungual desquamation, these KD cases also exhibited cough (69%), rhinorrhea (58%), and diarrhea (45%). Cases of KD had a significantly higher positive rate of viral isolation in comparison with the control group (7.5% vs. 2.2%, p = 0.02). Compared with the control group, cases of KD were more likely to have overall positive rates of viral PCR (50.4% vs. 16.4%, p < 0.001) and for various viruses including enterovirus (16.8% vs. 4.4%, p < 0.001), adenovirus (8.0% vs. 1.8%, p = 0.007), human rhinovirus (26.5% vs. 9.7%, p < 0.001), and coronavirus (7.1% vs. 0.9%, p = 0.003). CONCLUSION: We found that some common respiratory viruses, such as adenoviruses, enteroviruses, rhinoviruses, and coronaviruses, were associated with KD cases.

Breakthrough Streptococcus pneumoniae type 6B infection after adrenocorticotropic hormone therapy in a child vaccinated with pneumococcal conjugate vaccine.

Despite proven good efficacy of pneumococcal conjugated vaccine in preventing invasive pneumococcal disease, breakthrough infections remain a noticeable problem with significant morbidity and mortality, especially in selected high-risk groups. We present a 2-year-old girl with infantile spasm, who was treated with antiepileptic drugs and adrenocorticotropic hormone (ACTH). Vaccination with three doses 7-valent pneumococcal conjugate vaccine had been completed one month before ACTH therapy. Two months after ACTH therapy, she suffered from fever, cough, and decreased activity. Streptococcus pneumoniae, serotype 6B, was detected in blood culture. Vaccine failure could be possibly due to ACTH therapy.

Immunogenicity, reactogenicity, and safety of a human rotavirus vaccine, Rotarix, in Taiwanese infants who received a dose of hepatitis B immunoglobulin after birth.

UNLABELLED: This Phase-IV study evaluated the human rotavirus (RV) vaccine Rotarix (RIX4414) to provide additional local clinical data to the Taiwan Food and Drug Association (NCT01198769). Healthy infants aged 6-12 weeks who were given a hepatitis B immunoglobulin (HBIg) dose after birth, received two doses of RIX4414 (0, 2-month schedule). Anti-RV IgA antibody concentrations were measured using ELISA. A total of 15 infants were enrolled, and included in the according-to-protocol cohort. The anti-RV IgA antibody seroconversion rate 2 months post-Dose 2 was 100% (95% confidence interval = 78.2-100) and the geometric mean concentration was 254.7 U/ml (95% confidence interval = 145.0-447.7). Two episodes of gastroenteritis were reported, and one stool sample was tested for RV, which was negative. No fatal serious adverse events were reported during the study period between November 2010 and April 2011. The two-dose regimen of RIX4414 was highly immunogenic and safe when administered to healthy Taiwanese infants who received a HBIg dose after birth. TRIAL REGISTRATION NUMBER: NCT01198769.

Outbreak investigation in a COVID-19 designated hospital: The combination of phylogenetic analysis and field epidemiology study suggesting airborne transmission.

BACKGROUND: Healthcare-associated COVID-19 infections caused by SARS-CoV-2 have increased morbidity and mortality. Hospitals and skilled nursing facilities (SNFs) have been challenged by infection control and management. METHODS: This case study presents an outbreak investigation in a COVID-19-designated hospital and a hospital-based SNF. Real-time polymerase chain reaction (PCR) and other studies were performed on samples obtained from SNF residents, hospital patients, and healthcare workers (HCWs). The results of the laboratory tests and field epidemiological data were analyzed. Genome sequencing and phylogenetic analysis of SARS-CoV-2 were performed to identify the associations between cases. The tracer gas was released and recorded by a thermal imaging camera to investigate the spatial relations within clusters. RESULTS: During the outbreak, 29 COVID-19 infections in 3 clusters were identified through hospital-wide, risk-guided, and symptom-driven PCR tests. This included 12 HCWs, 5 patients, and 12 SNF residents who had been hospitalized for at least 14 days. Serology tests did not identify any cases among the PCR-negative individuals. The phylogenetic analysis revealed that viral strains from the 3 clusters shared a common mutation of G3994T and were phylogenetically related, which suggested that this outbreak had a common source rather than multiple introductions from the community. Linked cases exhibited vertical spatial distribution, and the sulfur hexafluoride release test confirmed a potential airborne transmission. CONCLUSIONS: This report addressed the advantage of a multi-disciplinary team in outbreak investigation. Identifying an airborne transmission within an outbreak highlighted the importance of regular maintenance of ventilation systems.

Community outbreak of adenovirus, Taiwan, 2011.

In 2011, a large community outbreak of human adenovirus (HAdV) in Taiwan was detected by a nationwide surveillance system. The epidemic lasted from week 11 through week 41 of 2011 (March 14-October 16, 2011). Although HAdV-3 was the predominant strain detected (74%), an abrupt increase in the percentage of infections caused by HAdV-7 occurred, from 0.3% in 2008-2010 to 10% in 2011. Clinical information was collected for 202 inpatients infected with HAdV; 31 (15.2%) had severe infection that required intensive care, and 7 of those patients died. HAdV-7 accounted for 10%, 12%, and 41% of infections among outpatients, inpatients with nonsevere infection, and inpatients with severe infection, respectively (p<0.01). The HAdV-7 strain detected in this outbreak is identical to a strain recently reported in the People's Republic of China (HAdV7-HZ/SHX/CHN/2009). Absence of circulating HAdV-7 in previous years and introduction of an emerging strain are 2 factors that caused this outbreak.

Rapid-test sensitivity for novel swine-origin pandemic influenza A.

BACKGROUND/PURPOSE: Rapid diagnosis of influenza was important in the global pandemic influenza A/H1N1 outbreak. The QuickVue Influenza A+B test is one of the most common tests for rapid diagnosis of influenza. We evaluated the sensitivity and specificity of the test in children. METHODS: We collected data from 970 patients with influenza-like illness who received rapid influenza antigen tests using the QuickVue Influenza A+B test as well as viral isolation. We compared the results with that of viral isolation and reverse-transcriptase polymerase chain reaction (RT-PCR) assays. RESULTS: Based on viral culture, the QuickVue Influenza A+B test had an overall sensitivity of 0.82 (419/513) and specificity of 0.99 (70/71), with a positive predictive value (PPV) of 0.74 (419/563) and a negative predictive value (NPV) of 0.77 (313/407). The sensitivity of QuickVue was significantly higher in specimens with high viral loads. If the viral loads were less than 10(6), the sensitivity of QuickVue was 0.62, while the sensitivity of QuickVue was 0.88 if the viral loads were higher than 10(6) (p<0.001). Logistic regression analysis showed that higher viral loads correlated with positive QuickVue results (p<0.001). On the first day of fever, the sensitivity of QuickVue was only 0.67; on the second day, the sensitivity was 0.86; on the third day, the sensitivity was 0.98, and on the fourth day, the sensitivity was 0.90. The sensitivity is significantly higher on days 2-3 in comparison with the first day of fever (p<0.05). We calculated the correlation of viral load and fever days, and the result showed higher mean viral load on the second and third days of fever. Age did not affect the sensitivity. CONCLUSION: In children, the sensitivity of QuickVue Influenza A+B test was 0.82. In addition, the sensitivity was significantly elevated in the higher viral load group and on the third day of fever.

Lack of resistance-associated mutations in UL54 and UL97 genes of circulating cytomegalovirus strains isolated in a medical center in Taiwan.

Human cytomegalovirus (HCMV) is a large DNA virus and a member of the betaherpesvirus family. HCMV infection is extremely common in human populations and can cause severe diseases in immunocompromised hosts. Ganciclovir is the most widely used antiviral drug for cytomegalovirus infection and works by blocking the amplification of HCMV. HCMV strains resistant to ganciclovir have been detected in recent decades and mainly result from mutations in UL97 (protein kinase) and UL54 (DNA polymerase) genes. In order to understand the prevalence of resistance of HCMV in Taiwan, we studied 40 clinical isolates to detect the mutations of UL97 and UL54 that might be related to resistance. The results showed that no mutation known to cause ganciclovir resistance was detected in any strain, but some polymorphisms (N685S, A688V, A885T, N898D in UL54; D605E in UL97) were frequently observed. Our results suggest that resistant HCMV strains are not prevalent in Taiwan.

A highly specific ELISA for diagnosis of 2009 influenza A (H1N1) virus infections.

BACKGROUND/PURPOSE: Accurate and timely diagnosis is vital for the clinical management of influenza. A 2009 pandemic influenza A (H1N1)-specific enzyme-linked immunosorbent assay (ELISA) was tested with selected clinical samples. METHODS: A selection of 90 throat swab samples with various viral loads of 2009 pandemic influenza A (H1N1) were tested. RESULTS: Using the reverse transcriptase polymerase chain reaction as a gold standard, the overall sensitivity (0.57) was higher than that of the QuickVue Influenza A+B Test (0.43). The specificity of the ELISA was 1.0 using the selected sample set. The positive and negative predictive values were 1 and 0.4, respectively. CONCLUSION: The ELISA is an easy to perform, highly specific, and fairly sensitive diagnostic tool for the 2009 pandemic influenza A (H1N1) virus infections. A strong correlation was found between viral load and specificity.

Risk factors of severe novel influenza A (H1N1) infections in hospitalized children.

BACKGROUND/PURPOSE: Data on hospitalized novel influenza A (H1N1) infected children are limited and urgently in demand. We conducted a clinical study to identify clinical features and risk factors associated with severe novel H1N1 infections of children in Taiwan. METHODS: From July 24, 2009 to December 4, 2009, data from 61 hospitalized children infected with 2009 novel H1N1 were collected. Demographics, underlying medical conditions, clinical data, receipt of antiviral therapy, need for intensive care and outcome were analyzed to identify clinical features and risk factors of severe infections. RESULTS: Of the 61 inpatients, the male to female ratio was 41 to 20 and the most common age group was between 6 and 12 years (36%). Almost all (98%) patients had fever, 53 (87%) patients received oseltamivir treatment and 51% of them received oseltamivir within 48 hours. Fourteen (23%) needed intensive care and 3 died. Obesity (a Body Mass Index ≥ 25 kg/m(2) in children ≥ 2 years of age, or a body weight ≥ the 95(th) percentile in children <2 years of age), dyspnea, C-reactive protein (CRP) > 3 mg/dL, pleural effusion, and delayed antiviral therapy were significantly associated with the need for intensive care and/or death. CONCLUSION: Obesity, dyspnea, CRP > 3 mg/dL, pleural effusion, and delayed antiviral therapy are significantly associated with severe novel H1N1 infections in children.

Viral load and clinical features in children infected with seasonal influenza B in 2006/2007.

BACKGROUND/PURPOSE: In influenza B infection, viral load is believed to be related to the severity of clinical illness. The correlation between viral load and symptoms is not known. We conducted a study to assess the relationship between virus load and clinical features in children infected with influenza B, in the hope that clinical features could be used as surrogate markers of viral load to guide treatment. METHODS: Between December 2006 and February 2007, 228 patients with fever and respiratory symptoms were prospectively enrolled in our tertiary hospital-based study. Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to determine viral load. RESULTS: Real-time RT-PCR was positive for influenza B in 76 patients. Using virus culture as the gold standard, the sensitivity and specificity were 95% and 87%, respectively. Influenza culture positive rate significantly correlated with viral load (p = 0.03). The median copy number of influenza B virus in the 76 RT-PCR positive patients was 9735 copies/ml (range 4.8×10¹-2.0×106 copies/ml). Samples obtained later in the clinical course tended to have lower viral load (p = 0.7), while patient age (p = 0.72) and fever duration (p = 0.96) positively related to viral load. In patients >3 years of age, myalgia was related to statistically lower viral loads (14300 vs. 1180; p = 0.025). Patients with chills tended to have higher viral loads (72450 vs. 7640; p = 0.1). Patients with abdominal pain tended to have lower viral loads (1998 vs. 12550; p = 0.06). CONCLUSION: Culture rate positively correlated with viral load. Patients with myalgia had a lower viral load.

In vitro activity of cefiderocol, cefepime/enmetazobactam, cefepime/zidebactam, eravacycline, omadacycline, and other comparative agents against carbapenem-non-susceptible Pseudomonas aeruginosa and Acinetobacter baumannii isolates associated from bloodstream infection in Taiwan between 2018-2020.

BACKGROUND/PURPOSE: This study aimed to investigate the in vitro susceptibilities of carbapenem-non-susceptible Pseudomonas aeruginosa (CNSPA) and Acinetobacter baumannii (CNSAB) isolates to cefiderocol, novel ß-lactamase inhibitor (BLI) combinations, new tetracycline analogues, and other comparative antibiotics. METHODS: In total, 405 non-duplicate bacteremic CNSPA (n = 150) and CNSAB (n = 255) isolates were collected from 16 hospitals in Taiwan between 2018 and 2020. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method, and susceptibilities were interpreted according to the relevant guidelines or in accordance with results of previous studies and non-species-related pharmacokinetic/pharmacodynamic data. RESULTS: Among the isolates tested, cefiderocol demonstrated potent in vitro activity against CNSPA (MIC50/90, 0.25/1 mg/L; 100% of isolates were inhibited at ≤4 mg/L) and CNSAB (MIC50/90, 0.5/2 mg/L; 94.9% of isolates were inhibited at ≤4 mg/L) isolates. More than 80% of CNSPA isolates were susceptible to cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, and amikacin, based on breakpoints established by the Clinical and Laboratory Standards Institute. Activities of new BLI combinations varied significantly. Tetracycline analogues, including tigecycline (MIC50/90, 1/2 mg/L; 92.5% of CNSAB isolates were inhibited at ≤2 mg/L) and eravacycline (MIC50/90, 0.5/1 mg/L; 99.6% of CNSAB isolates were inhibited at ≤2 mg/L) exhibited more potent in vitro activity against CNSAB than omadacycline (MIC50/90, 4/8 mg/L). CONCLUSIONS: The spread of CNSPA and CNSAB poses a major challenge to global health. Significant resistance be developed even before a novel agent becomes commercially available. The development of on-site antimicrobial susceptibility tests for these novel agents is of great clinical importance.