High hemolytic activity of the Staphylococcus aureus spa t1081 among clonal complex 45 in Taiwan.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 was first reported in Taiwan in 2006. Since then, the prevalence of ST45 MRSA in clinical isolates has increased. This study was carried out to understand the changes in the proportions, evolutionary relationships, and infection advantages of ST45 and its related clones. MATERIALS AND METHODS: S. aureus including MRSA and MSSA (methicillin-sensitive S. aureus), and clonal complex (CC) 45 blood isolates were collected in 2000, 2005, and from January 2010 to August 2014. Molecular typing, multiple-locus variable-number tandem repeat analysis (MLVA) and single nucleotide polymorphism (SNP)-based phylogenetic analysis were performed. Fitness and virulence analyses were used to understand the infection advantages of the isolates. RESULTS: Among the 67 CC45 isolates, only MSSA ST508 isolates were found in 2000 and 2005. Since 2010, the prevalence of MRSA has increased, t1081/ST45 has become dominant, and MRSA ST508 has been found. Phylogenetic analysis indicated that most of the ST45 isolates were located in a cluster distinct from those of ST508 and ST929. However, the t026 isolates clustered with the ST508 isolates rather than with the other ST45 isolates. Moreover, fitness and virulence analyses revealed that the t1081 isolates had higher hemolytic activity than the t026 and ST508 isolates did. CONCLUSION: Our findings indicated that the increased prevalence of ST45 MRSA isolates from blood cultures in Taiwan was due to the t1081 isolates, and their high hemolytic activity may provide an infection advantage.

High hemolytic activity in Staphylococcus aureus t1081/ST45 due to increased hla protein production and potential RNAIII-independent regulation.

BACKGROUND: α-Hemolysin, encoded by hla, is a major virulence factor of Staphylococcus aureus. Sequence type (ST) 45 is a globally spread clone with increasing clinical prevalence in Taiwan. Our previous study showed that among the CC45 isolates, the spa type t1081 isolates presented greater hemolytic activity. MATERIALS AND METHODS: The hemolytic activity of 67 CC45 isolates (44 t1081 and 23 non-t1081) from clinical blood cultures was assessed using rabbit red blood cells. The sequences of hla and its upstream regulatory regions and RNAIII were compared between the two groups. The expression of hla and its regulators RNAIII, mgrA, and saeR was analyzed via qRT‒PCR, while Hla protein levels were measured via Western blotting. RESULTS: Compared with non-t1081 isolates, t1081 isolates presented increased hemolytic activity. No significant differences in hla sequences, upstream regulatory regions, or gene expression levels were detected between the two groups. The expression of the transcriptional regulators mgrA and saeR was also similar between the two groups. Western blotting revealed increased Hla protein in the t1081 isolates. However, neither the sequence or expression of RNAIII, a regulator of hla at both the transcriptional and posttranscriptional levels, differed between the groups. CONCLUSION: Our study revealed that, compared with other CC45 isolates, the t1081/ST45 isolates presented greater hemolytic activity. This heightened activity was due mainly to increased Hla protein levels. Moreover, the higher translation levels may be independent of the known regulator RNAIII, indicating a potential RNAIII-independent mechanism for Hla regulation.

The emergence of transposon-driven multidrug resistance in invasive nontypeable Haemophilus influenzae over the last decade.

Nontypeable Haemophilus influenzae (NTHi), once considered a harmless commensal, has emerged as a significant concern due to the increased prevalence of multidrug-resistant (MDR) strains and their association with invasive infections. This study aimed to explore the epidemiology and molecular resistance mechanisms of 51 NTHi isolates collected from patients with invasive infections in northern Taiwan between 2011 and 2020. This investigation revealed substantial genetic diversity, encompassing 29 distinct sequence types and 18 clonal complexes. Notably, 68.6% of the isolates exhibited ampicillin resistance, with 28 categorised as MDR and four isolates were even resistant to up to six antibiotic classes. Among the MDR isolates, 18 pulsotypes were identified, indicating diverse genetic lineages. Elucidation of their resistance mechanisms revealed 18 ß-lactamase-producing amoxicillin-clavulanate-resistant (BLPACR) isolates, 12 ß-lactamase-producing ampicillin-resistant (BLPAR) isolates, and 5 ß-lactamase-nonproducing ampicillin-resistant (BLNAR) isolates. PBP3 analysis revealed 22 unique substitutions in BLPACR and BLNAR, potentially contributing to cephem resistance. Notably, novel transposons, Tn7736-Tn7739, which contain critical resistance genes, were discovered. Three strains harboured Tn7739, containing seven resistance genes [aph(3')-Ia, blaTEM-1, catA, sul2, strA, strB, and tet(B)], while four other strains carried Tn7736, Tn7737, and Tn7738, each containing three resistance genes [blaTEM-1, catA, and tet(B)]. The emergence of these novel transposons underscores the alarming threat posed by highly resistant NTHi strains. Our findings indicated that robust surveillance and comprehensive genomic studies are needed to address this growing public health challenge.

Comparison of ERIC carbapenem-resistant Enterobacteriaceae test, BD Phoenix CPO detect panel, and NG-test CARBA 5 for the detection of main carbapenemase types of carbapenem-resistant Enterobacterales.

BACKGROUND: This study aimed to assess the performance of three commercial panels, the ERIC Carbapenem-Resistant Enterobacteriaceae Test (ERIC CRE test), the NG-Test CARBA 5 (NG CARBA 5), and the BD Phoenix CPO Detect Panel (CPO panel), for the detection of main types of carbapenemases among carbapenem-resistant Enterobacterales (CRE). METHODS: We collected 502 isolates of carbapenem-resistant Enterobacterales (CRE) demonstrating intermediate or resistant profiles to at least one carbapenem antibiotic (ertapenem, imipenem, meropenem, or doripenem). Carbapenemase genes and their specific types were identified through multiplex PCR and sequencing methods. Subsequently, the ERIC CRE test, CPO panel, and NG CARBA 5 assay were conducted on these isolates, and the results were compared with those obtained from multiplex PCR. RESULTS: The results indicated that the ERIC CRE test exhibited an overall sensitivity and specificity of 98.1% and 93.6%, respectively, which were comparable to 99.1% and 90.6% for the NG CARBA 5. However, the CPO panel demonstrated a sensitivity of only 56.2% in identifying Ambler classes, exhibiting the poorest sensitivity for class A. Moreover, while the ERIC CRE test outperformed the NG CARBA 5 in identifying multi-gene isolates with multiple carbapenemase-encoding genes, the CPO panel failed to accurately classify these isolates. CONCLUSIONS: Our findings support the utilization of the ERIC CRE test as one of the methods for detecting carbapenemases in clinical laboratories. Nonetheless, further optimization is imperative for the CPO panel to enhance its accuracy in determining carbapenemase classification and address limitations in detecting multi-gene isolates.

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.

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.

Impact of coronavirus disease 2019 (COVID-19) on antimicrobial resistance among major pathogens causing healthcare-associated infection.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has caused great impact on healthcare systems, including antibiotic usage and multi-drug resistant (MDR) bacterial infections at hospitals. We aim to investigate the trends of antimicrobial resistance among the major pathogens causing healthcare-associated infection (HAI) at intensive care units (ICU). MATERIAL AND METHODS: The demographic characteristics of hospitalization, usage of antimicrobial agents, counted by half-an-year DID (defined daily dose per 1000 patient-days), and HAI density of five major MDR bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Klebsiella pneumoniae (CRKP), and carbapenem-resistant Pseudomonas aeruginosa (CRPA), of ICU patients at a medical center in Taiwan during January 2017 to December 2021 were collected and analyzed. RESULTS: The total antibiotic usage, counted by DID, had a significant increasing trend, before COVID-19 occurrence in 2017-2019, but no further increase during the pandemic period in 2020-2021. However, comparing the two time periods, antibiotics consumption was significantly increased during pandemic period. There was no significant change of HAI density in MRSA, VRE, CRAB, CRKP, and CRPA, comparing the pandemic to the pre-pandemic period. Although, CRKP and CRPA infection rates were increasing during the pre-pandemic period, there was no further increase of CRKP and CRPA HAI rates during the pandemic period. CONCLUSION: During COVID-19 pandemic, there was no significant increase in HAI density of five major MDR bacteria at ICU in Taiwan, despite increased antibiotic usage. Strict infection prevention measures for COVID-19 precautions and sustained antimicrobial stewardship probably bring these effects.

Performance assessment of the Bruker Biotyper MALDI-TOF MS for the identification of difficult-to-identify viridans group streptococci.

Differentiating Streptococcus pneumoniae among nonpneumococcal viridans group streptococci (VGS) is challenging in conventional laboratories. Therefore, we aimed to evaluate the performance of the latest Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system in identifying VGS by comparing the results to those of the specific gene sequencing approach. Clinical isolates were initially identified using the BD Phoenix system to identify Streptococcus species. The optochin test was used to distinguish nonpneumococcal VGS from S. pneumoniae. The species of individual reference strains and clinical isolates were determined by comparing the sequences of the 16S rDNA, gyrB, sodA, groESL, or coaE genes with those in the GenBank sequence databases. We evaluated the performance of the Bruker Biotyper MALDI-TOF MS in VGS identification using two different machines with three databases. We collected a total of 103 nonpneumococcal VGS and 29 S. pneumoniae blood isolates at a medical center in northern Taiwan. Among these isolates, only seven could not be identified at the species level by the specific gene sequencing approach. We found that none of the nonpneumococcal VGS isolates were misidentified as pneumococci by the latest Biotyper system, and vice versa. However, certain strains, especially those in the mitis and bovis groups, could still not be correctly identified. The latest Bruker Biotyper 4.1 (DB_10833) showed significant improvement in identifying VGS strains. However, a specific gene sequencing test is still needed to precisely differentiate the species of strains in the mitis and bovis groups.

Nontuberculous mycobacterial infection mimicking gynecologic malignancy in a woman living with HIV.

The weakened immune system in people living with HIV (PLWH) can lead to infectious diseases occurring more aggressively and mimicking the clinical manifestations of malignancies. Mycobacterium sherrisii, a slow-growing nontuberculous mycobacterium, may cause opportunistic infections among PLWH. We present a case of a 41-year-old woman who initially presented with fever, vaginal spotting, and a bulky pelvic mass, raising suspicion of uterine malignancy. Following a surgical resection, she was pathologically diagnosed with leiomyoma and endometriosis. However, during an event of needlestick injury, she was unexpectedly found to be HIV-infected and the CD4 count was 157 cells/µL at diagnosis, which prompted a diagnostic work-up for opportunistic infections. The diagnosis of disseminated M. sherrisii infection was confirmed through cultures and special staining of specimens obtained from the pelvic tumor and blood. Subsequently, she was treated with a combination of ethambutol, azithromycin, and levofloxacin. Two months after treatment, abdominal and pelvic computed tomography revealed no evidence of recurrent tumor or abscess formation. Given the frequent association of pelvic masses with gynecologic malignancies in women living with HIV, it can be challenging to differentiate between a cancerous lesion and an infectious process, emphasizing the need for meticulous investigations to minimize the potential for misdiagnosis.

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.

Prevalence, Associated Factors, and Appropriateness of Empirical Treatment of Trichomoniasis, Bacterial Vaginosis, and Vulvovaginal Candidiasis among Women with Vaginitis.

Trichomoniasis (TV), bacterial vaginosis (BV), and vulvovaginal candidiasis (VVC) are the most common causes of vaginitis. This study investigated the prevalence of these diagnoses, their associated factors, and the appropriateness of the empirical treatment. From March 25, 2019, to June 17, 2022, 429 women with symptoms or signs of vaginitis were enrolled in a hospital in northern Taiwan with 438 episodes of vaginitis. Vaginal swabs were collected for Gram's staining, in vitro cultures for Trichomonas vaginalis, bacteria, and yeasts, and multiplex PCR assay for TV, BV, and VVC. Their empirical treatments were recorded. Factors associated with different etiologies of vaginitis were sought in multivariable logistic regression models. The prevalence of TV, BV, and VVC were 2.1%, 22.8%, and 21.7%, respectively, while coinfections of BV and VVC, TV and BV, TV and VVC, and triple infection occurred in 5.0%, 0.2%, 0.2%, and 0.7%, respectively. Multivariable analyses revealed that having multiple sexual partners was associated with TV and BV (adjusted odds ratio [aOR] 9.756 and 3.246, respectively), while menopausal women were less likely to have VVC (aOR 0.184). Moreover, dysuria was associated with TV (aOR 4.981), vaginal itch and pelvic pain with VVC (aOR 3.223 and 0.425, respectively), and discharge pH > 4.5 with BV (aOR 1.767). Other clinical symptoms and pelvic examination features had limited value for differential diagnosis. Among the 78 empirical antifungal and metronidazole prescriptions, 55.2% were ineffective or unnecessary. Our study highlights the importance to integrate appropriate diagnostic tools into the clinical care of women with vaginitis. IMPORTANCE Vaginal complaints are widespread among women and are associated with emotional, physical, and economic burdens with challenges in their diagnosis and management. In this survey, we identified that 40% of vaginitis in Taiwan was caused by either trichomoniasis, bacterial vaginosis, vulvovaginal candidiasis, or a combination of these infections. Our data suggested that typical physical findings appeared infrequently among women with these infections and their empirical treatments were frequently inappropriate. Our findings highlighted the importance of integrating proper diagnostic tools into clinical practice to improve the diagnosis and management of vaginitis, as recommended by national and international guidelines.

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.

A difficult-to-treat pleuropulmonary histoplasmosis in a patient with rheumatoid arthritis in Taiwan.

Amphotericin B and itraconazole are the primary agents for treating histoplasmosis. Newer azoles are alternatives for patients refractory to or intolerant of standard therapy. We report an 83-year-old woman with rheumatoid arthritis complicated with pleuropulmonary histoplasmosis who responded to liposomal amphotericin B, but progressed under voriconazole and posaconazole maintenance therapy.

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.

Disseminated Mycobacterium chimaera infection in a patient with adult-onset immunodeficiency syndrome: case report.

BACKGROUND: Patients with adult-onset immunodeficiency syndrome due to anti-interferon-γ autoantibodies (AIGAs) are susceptible to disseminated Mycobacterium avium complex (MAC) infections. M. chimaera, a newly identified MAC species, is distinguished from the others due to the reduced virulence. Previous cases of disseminated M. chimaera infection have been linked to cardiothoracic surgery. Reports of disseminated M. chimaera in patients without a history of cardiothoracic surgery are rare. CASE PRESENTATION: A 57-year-old Asian man, previously healthy, presented with fever, dry cough, exertional dyspnea, and decreased appetite. The delayed resolution of pneumonia despite antibiotic treatment prompted further imaging studies and biopsies from the lung and lymph node. The fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) demonstrated intense uptake in lung consolidations and diffuse lymphadenopathy. Cultures of the specimens obtained from sputum, blood, stool, lung tissue, and lymph node grew M. chimaera. Further immunological evaluation disclosed the presence of neutralizing AIGAs, which possibly led to acquired immunodeficiency and disseminated M. chimaera infection. CONCLUSIONS: We herein present the first case of adult-onset immunodeficiency due to AIGAs complicated with disseminated M. chimaera infection. Further immunological evaluation, including AIGAs, may be warranted in otherwise healthy patients who present with disseminated mycobacterial infection.

Staphylococcus taiwanensis sp. nov., isolated from human blood.

A novel coagulase-negative Staphylococcus strain (NTUH-S172T) was isolated from human blood culture in Taiwan with preliminary identification of Staphylococcus saprophyticus. 16S rRNA gene analysis and multilocus sequence analysis (MLSA) showed that NTUH-S172T was most closely related to Staphylococcus haemolyticus. The average nucleotide identity and digital DNA-DNA hybridization values with the whole genome sequence were <95 % and<70 % when compared to the related species. Strain NTUH-S172T could be distinguished from S. haemolyticus by urease production and from Staphylococcus borealis by nitrate reduction. In addition, the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) spectrum of NTHU-S172T was significantly different from that of S. haemolyticus, which could be used in clinical identification. In conclusion, it is proposed that this isolate represents a novel species, named Staphylococcus taiwanensis sp. nov., with type strain NTUH-S172T (=BCRC 81315T=JCM 34726T).

Mycobacterium gordonae infection in immunocompromised and immunocompetent hosts: A series of seven cases and literature review.

BACKGROUND/PURPOSE: Mycobacterium gordonae is a ubiquitous environmental mycobacteria and has been long considered an opportunistic pathogen, causing infections only in immunocompromised hosts. Cases of M. gordonae related infections in immunocompetent host have rarely been reported, and the pathogenicity of M. gordonae remained uncertain. METHODS: From January 2016 to December 2018, seven cases of M. gordonae infection were diagnosed and treated at National Taiwan University Hospital. RESULTS: Six cases had at least one underlying disease affecting immune status, while one case had no identifiable underlying disease. The sites of infection were lung (n = 3), skin and soft tissue (n = 3), and one had disseminated disease involving the lung and bone marrow. All patients were cured after anti-mycobacterial treatment, except one patient died of refractory leukemia. CONCLUSION: Compatible with the literature reports, we demonstrate that M. gordonae could be pathogenic and causing infection not only in the immunocompromised host, but also in the otherwise healthy population. Multi-antimicrobial combination and adequate source control could have good therapeutic effect for patients with M. gordonae infections.