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.

Dynamic change of surface microbiota with different environmental cleaning methods between two wards in a hospital.

Terminal disinfection and daily cleaning have been performed in hospitals in Taiwan for many years to reduce the risks of healthcare-associated infections. However, the effectiveness of these cleaning approaches and dynamic changes of surface microbiota upon cleaning remain unclear. Here, we report the surface changes of bacterial communities with terminal disinfection and daily cleaning in a medical intensive care unit (MICU) and only terminal disinfection in a respiratory care center (RCC) using 16s ribosomal RNA (rRNA) metagenomics. A total of 36 samples, including 9 samples per sampling time, from each ward were analysed. The clinical isolates were recorded during the sampling time. A large amount of microbial diversity was detected, and human skin microbiota (HSM) was predominant in both wards. In addition, the colonization rate of the HSM in the MICU was higher than that in the RCC, especially for Moraxellaceae. A higher alpha-diversity (p = 0.005519) and a lower UniFrac distance was shown in the RCC due to the lack of daily cleaning. Moreover, a significantly higher abundance among Acinetobacter sp., Streptococcus sp. and Pseudomonas sp. was shown in the RCC compared to the MICU using the paired t test. We concluded that cleaning changes might contribute to the difference in diversity between two wards.

Transforming growth factor beta 1 increases collagen content, and stimulates procollagen I and tissue inhibitor of metalloproteinase-1 production of dental pulp cells: Role of MEK/ERK and activin receptor-like kinase-5/Smad signaling.

BACKGROUND/PURPOSE: In order to clarify the role of transforming growth factor beta 1 (TGF-ß1) in pulp repair/regeneration responses, we investigated the differential signaling pathways responsible for the effects of TGF-ß1 on collagen turnover, matrix metalloproteinase-3 (MMP-3), and tissue inhibitor of metalloproteinase-1 (TIMP-1) production in human dental pulp cells. METHODS: Pulp cells were exposed to TGF-ß1 with/without pretreatment and coincubation by 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenyl mercapto)butadiene (U0126; a mitogen-activated protein kinase kinase [MEK]/extracellular signal-regulated kinase [ERK] inhibitor) and 4-(5-benzol[1,3]dioxol-5-yl-4-pyrldin-2-yl-1H- imidazol-2-yl)-benzamide hydrate (SB431542; an activin receptor-like kinase-5/Smad signaling inhibitor). Sircol collagen assay was used to measure cellular collagen content. Culture medium procollagen I, TIMP-1, and MMP-3 levels were determined by enzyme-linked immunosorbent assay. RESULTS: TGF-ß1 increased the collagen content, procollagen I, and TIMP-1 production, but slightly decreased MMP-3 production of pulp cells. SB431542 and U0126 prevented the TGF-ß1-induced increase of collagen content and TIMP-1 production of dental pulp cells. CONCLUSION: These results indicate that TGF-ß1 may be involved in the healing/regeneration processes of dental pulp in response to injury by stimulation of collagen and TIMP-1 production. These events are associated with activin receptor-like kinase-5/Smad2/3 and MEK/ERK signaling.

Application of 16S rRNA metagenomics to analyze bacterial communities at a respiratory care centre in Taiwan.

In this study, we applied a 16S ribosomal RNA (rRNA) metagenomics approach to survey inanimate hospital environments (IHEs) in a respiratory care center (RCC). A total of 16 samples, including 9 from medical devices and 7 from workstations, were analyzed. Besides, clinical isolates were retrospectively analyzed during the sampling period in the RCC. A high amount of microbial diversity was detected, with an average of 1,836 phylotypes per sample. In addition to Acinetobacter, more than 60 % of the bacterial communities present among the top 25 abundant genera were dominated by skin-associated bacteria. Differences in bacterial profiles were restricted to individual samples. Furthermore, compliance with hand hygiene guidelines may be unsatisfactory among hospital staff according to a principal coordinate analysis that indicated clustering of bacterial communities between devices and workstations for most of the sampling sites. Compared to the high incidence of clinical isolates in the RCC, only Staphylococcus and Acinetobacter were highly abundant in the IHEs. Despite Acinetobacter was the most abundant genus present in IHEs of the RCC, potential pathogens, e.g., Acinetobacter baumannii, might remain susceptible to carbapenem. This study is the first in Taiwan to demonstrate a high diversity of human-associated bacteria in the RCC via 16S rRNA metagenomics, which allows for new assessment of potential health risks in RCCs, aids in the evaluation of existing sanitation protocols, and furthers our understanding of the development of healthcare-associated infections.

Prevalence and mapping of a plasmid encoding a type IV secretion system in Acinetobacter baumannii.

We investigated the prevalence of a type IV secretion system (T4SS)-bearing plasmid among clinical isolates of carbapenem-resistant Acinetobacter baumannii (CRAB) using plasmid replicon typing. The complete sequence of a T4SS-bearing plasmid, pAB_CC, isolated from A. baumannii TYTH-1 was determined, and a comparative analysis of the T4SS gene modules was performed. Of the 129 isolates studied, GR6 (repAci6) was the most common (45 of 96 isolates) and was strongly linked with the T4SS. A comparative analysis of the T4SS locus in seven plasmid genomes, including pAB_CC, pACICU2, pABKp1, pABTJ1, p1BJAB0714, p2BJAB0868, and p2ABTCDC0715, indicated that fourteen genes on these plasmids were highly conserved compared to those of the F plasmid. Additionally, the chromosomes in the seven representative isolates may be evolutionarily distinct from their intrinsic T4SS-bearing plasmids, suggesting that the two T4SS lineages emerged long before the appearance of EC II. These two lineages are now widespread in A. baumannii strains.

Transcriptome profiling in imipenem-selected Acinetobacter baumannii.

BACKGROUND: Carbapenem-resistance in Acinetobacter baumannii has gradually become a global challenge. To identify the genes involved in carbapenem resistance in A. baumannii, the transcriptomic responses of the completely sequenced strain ATCC 17978 selected with 0.5 mg/L (IPM-2 m) and 2 mg/L (IPM-8 m) imipenem were investigated using RNA-sequencing to identify differences in the gene expression patterns. RESULTS: A total of 88 and 68 genes were differentially expressed in response to IPM-2 m and IPM-8 m selection, respectively. Among the expressed genes, 50 genes were highly expressed in IPM-2 m, 30 genes were highly expressed in IPM-8 m, and 38 genes were expressed common in both strains. Six groups of genes were simultaneously expressed in IPM-2 m and IPM-8 m mutants. The three gene groups involved in DNA recombination were up-regulated, including recombinase, transposase and DNA repair, and beta-lactamase OXA-95 and homologous recombination. The remaining gene groups involved in biofilm formation were down-regulated, including quorum sensing, secretion systems, and the csu operon. The antibiotic resistance determinants, including RND efflux transporters and multidrug resistance pumps, were over-expressed in response to IPM-2 m selection, followed by a decrease in response to IPM-8 m selection. Among the genes over-expressed in both strains, blaOXA-95, previously clustered with the blaOXA-51-like family, showed 14-fold (IPM-2 m) to 330-fold (IPM-8 m) over-expression. The expression of blaOXA-95 in IPM-2 m and IPM-8 m cells was positively correlated with the rate of imipenem hydrolysis, as demonstrated through Liquid Chromatography-Mass Spectrometry/Mass Spectrometry, suggesting that blaOXA-95 plays a critical role in conferring carbapenem resistance. In addition, A. baumannii shows an inverse relationship between carbapenem resistance and biofilm production. CONCLUSION: Gene recombination and blaOXA-95 play critical roles in carbapenem resistance in A. baumannii. Taken together, the results of the present study provide a foundation for future studies of the network systems associated with carbapenem resistance.

Applying Microsoft Power Platform to Improve Healthcare Worker Health Monitoring Processes.

Through the Microsoft Power Platform, we have developed a mobile health monitoring application, simplifying the reporting process with an individual reporting mode. Employees simply click "Very Healthy" or "Health Abnormality" and fill out the relevant information. Automated reports reduce managerial workload, enhancing satisfaction.

Emergence of extensively drug-resistant hypervirulent Acinetobacter baumannii isolated from patients with bacteremia: bacterial phenotype and virulence analysis.

OBJECTIVES: Individuals infected with extensively drug-resistant (XDR) Acinetobacter baumannii are difficult to cure and have a high mortality rate. In this study, we compared the genomic and phenotypic differences between XDR and non-multidrug-resistant (MDR) A. baumannii and further characterized hypervirulent XDR A. baumannii. METHODS: A total of 1,403 Acinetobacter isolates were collected from patients with bacteremia between 1997 and 2015. Antimicrobial susceptibility test was performed to categorize isolates into non-MDR, MDR, and XDR groups. The presence of selected virulence-associated genes was determined by PCR. Bacterial phenotypes, including iron acquisition, biofilm formation, capsule production, and virulence to larvae and mice, were determined. RESULTS: Multilocus sequence types revealed the high prevalence of ST2 (81.6%) and ST129 (18.4%) among 49 XDR isolates and sequence types of 18 non-MDR isolates were more diverse. Virulence-associated phenotypic assays showed that XDR isolates had higher iron acquisition ability and capsule production and higher virulence to Galleria mellonella larvae. However, their biofilm formation ability was lower compared to that of non-MDR isolates. XDR isolates contained more virulence genes, tonB, hemO, abaI, and ptk, while non-MDR isolates contained more pld and ompA. Twenty-one XDR isolates caused <20% larvae survival rate after 7 days post-infection were defined as hypervirulent XDR isolates. Among them, isolates 1677 (ST129) and 929-1 (ST2) also caused the death of all infected mice within two days. CONCLUSION: Some subpopulations of highly drug-resistant ST2 also exhibit high virulence. Therefore, it is of utmost importance to continue monitoring the spread of hypervirulent XDR A. baumannii isolates.

Polypharmacy and potential drug-drug interactions among people living with HIV in the era of integrase strand transfer inhibitor-based antiretroviral therapy.

OBJECTIVES: To investigate the prevalence of polypharmacy and potential drug-drug interactions (DDIs), and the factors associated with DDIs among people living with human immunodeficiency virus (HIV; PLWH) in the modern era of antiretroviral therapy (ART). METHODS: This cross-sectional study included PLWH who had been on ART for ≥3 months at two designated HIV hospitals in Taiwan. All ART and non-ART prescriptions were collected from the NHI-MediCloud System and screened for DDIs using the University of Liverpool HIV drug interactions database. A case-control analysis was conducted to investigate the factors associated with DDIs. RESULTS: In total, 1007 PLWH were included in this study from June 2021 to August 2022. The median age was 40 (interquartile range 33-49) years, and 96.2% were taking integrase strand transfer inhibitor (INSTI)-based ART. The proportions of PLWH with at least one non-communicable disease and polypharmacy were 50.0% and 18.7%, respectively. Seven (0.7%) PLWH had red-flagged DDIs, and 159 (15.8%) had amber-flagged DDIs. In multi-variable models, the prevalence of DDIs was associated with older age [adjusted odds ratio (aOR) per 1-year increase 1.022), number of co-medications (aOR 1.097), use of boosted INSTI-based ART (vs unboosted INSTI, aOR 8.653), and concomitant medications in the alimentary tract and metabolism category (aOR 11.058) and anti-neoplastic and immunomodulating agents (aOR 14.733). CONCLUSIONS: In the INSTI era, the prevalence of potential DDIs is lower than noted previously, but remains substantial. Clinicians should monitor DDIs routinely, especially in older PLWH, those taking a higher number of co-medications, and those who are taking booster-containing ART or medications from specific categories.

Far-UVC light (222 nm) efficiently inactivates clinically significant antibiotic-resistant bacteria on diverse material surfaces.

In recent years, there has been a gradual increase in the prevalence of drug-resistant bacteria, primarily attributed to the widespread use of antibiotics. This has resulted in heightened mortality rates, morbidity, and exorbitant healthcare costs associated with antibiotic-resistant bacterial infections. In order to mitigate the spread of antibiotic-resistant bacteria, environmental disinfection plays a crucial role. Ultraviolet radiation C (UVC) light disinfection has emerged as a potent technique to limit the transmission of nosocomial pathogens and prevent healthcare-associated infections. Different types of high-touch surfaces were used. A serial disinfected experiment with different 222 nm UVC dosages was conducted on clinically isolated antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus species (VRE), carbapenem-resistant Escherichia coli (CREC), carbapenem-resistant Klebsiella pneumonia (CRKP), carbapenem-resistant Acinetobacter baumannii (CRAB), and carbapenem-resistant Pseudomonas aeruginosa (CRPA) on different material surfaces. The bactericidal efficacy was evaluated by The Clinical & Laboratory Standards Institute (CLSI) guidelines. 222 nm UVC irradiation had a potent bactericidal efficacy on clinical antibiotic-resistant bacteria on different high-touch surfaces that are commonly found in the environment and healthcare facilities. 222 nm UVC irradiation time was tested from 10 s to 1 h. Different surfaces affect the efficiency of 222 nm UVC. The more adsorptive a material is, the higher the dosage of 222 nm UVC irradiation energy is required for effective disinfection. The use of 222 nm UVC lamps for disinfection on different materials has been shown to be a useful method. However, it is crucial to pay attention to the energy required for effective sterilization. IMPORTANCE: This study is crucial, providing compelling evidence on Far-ultraviolet radiation C (Far-UVC) light's efficacy against clinically significant antibiotic-resistant bacteria-a pressing issue in microbiology and infection control. Our research employs antibiotic-resistant strains from clinically isolated bacteria, emphasizing real-world relevance. Simultaneously, we assess Far-UVC light (222 nm) across diverse material surfaces commonly found in clinical settings. This dual approach ensures practical applicability and broad relevance. Our comprehensive setup and rigorous methodologies unequivocally demonstrate Far-UVC light's potency in combating antibiotic-resistant bacteria. Since 222 nm far-UVC has a disinfection capability and is harmless to mammalian cells, this dual effectiveness positions Far-UVC as a secure tool for infection control, with potential applications in healthcare settings, mitigating antibiotic-resistant bacteria spread, and reducing healthcare-associated infections.

First report of the chromosomal integration of carbapenemase gene blaIMP-19 in Acinetobacter baumannii AB322: the legacy of integron in phage-plasmid?

Integration of carbapenemase gene blaIMP into the chromosome of carbapenem-resistant Acinetobacter baumannii (CRAB) has not been reported. The aim of this study was to explore the genomic characteristics of CRAB AB322 isolated from a Taiwanese patient diagnosed with bacteremia in 2011, whose chromosome harbors blaIMP-19. Disk diffusion and broth microdilution were employed to analyze the antimicrobial susceptibility of AB322 to 14 antimicrobials. Nanopore whole-genome sequencing platform was utilized for AB322 genome sequencing, and conjugation was further performed to investigate the transferability of blaIMP-19 to amikacin-resistant A. baumannii 218 (AB218) and Acinetobacter nosocomialis 254 (AN254). The results showed that AB322 was classified as multidrug-resistant A. baumannii but remained susceptible to ampicillin/sulbactam, colistin, and tigecycline. Whole-genome sequencing revealed the AB322 genome, consisting of a 4,098,985-bp chromosome, a 71,590-bp conjugative plasmid named pAB322-1, and an 8,726-bp plasmid named pAB322-2. Multilocus sequence typing analysis indicated that AB322 belonged to sequence type 1. AB322 chromosome harbored numerous acquired antimicrobial resistance genes, including aph(3')-Ia, aadA1b, aadA1, aac(6')-Ib3, aac (3)-Ia, blaADC-25, blaOXA-69, blaIMP-19, catA1, sul1, and tet(A), conferring resistance to ß-lactams, aminoglycosides, chloramphenicol, sulfamethoxazole, and tetracyclines. Moreover, blaIMP-19 was identified to be situated within class 1 integron In240 and an incomplete PHAGE_Salmon_SJ46_NC_031129 on AB322 chromosome. However, conjugation experiments revealed that blaIMP-19 could not be transferred to AB218 and AN254 in our testing conditions. In conclusion, we first report the presence of chromosomal-integrated blaIMP-19 in CRAB, possibly mediated by integron. The future dissemination of blaIMP-19 among different species, leading to carbapenem resistance dissemination, requires close monitoring. IMPORTANCE: The horizontal transfer of antimicrobial-resistant genes is crucial for the dissemination of resistance, especially as Acinetobacter baumannii has emerged as a clinically significant pathogen. However, in this study, we first report the integration of the blaIMP-19 gene into the chromosome of A. baumannii, and such horizontal transfer may be associated with integron-phage elements. Additionally, it is possible that these DNA fragments carrying antimicrobial-resistant genes could further spread to other pathogens by moving horizontally onto conjugative plasmids.

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.

Genome sequence of Acinetobacter baumannii TYTH-1.

Acinetobacter baumannii has emerged recently as a major cause of health care-associated infections due to the extent of its antimicrobial resistance and its propensity to cause large nosocomial outbreaks. Here we report the genome sequence of Acinetobacter baumannii TYTH-1 isolated in Taiwan during 2008.

d-mannose-sensitive pilus of Acinetobacter baumannii is linked to biofilm formation and adherence onto respiratory tract epithelial cells.

BACKGROUND/PURPOSE: Acinetobacter baumannii is an important nosocomial pathogen. To better understand the role of CsuA/BABCDE pilus of A. baumannii in virulence, bacterial biofilm formation, adherence and carbohydrate-mediated inhibition were conducted. METHODS: CsuA/BABCDE pilus-producing (abbreviated Csu pilus) operon of A. baumannii ATCC17978 was cloned for analysis of biofilm formation on an abiotic plastic plate, bacterial adherence to respiratory epithelial human A549 cells and carbohydrate-mediated inhibition. The carbohydrates used for inhibition of biofilm formation and adherence to A549 cells included monosaccharides, pyranosides, and mannose-polymers. RESULTS: The Csu pilus of A. baumannii ATCC17978 was cloned and expressed into a non-pilus-producing Escherichia coli JM109, and was knocked out as well. The recombinant Csu (rCsu) pilus on E. coli JM109/rCsu pilus-producing clone observed by both electro-microscopy and atomic force microscopy showed abundant, while Csu-knockout A. baumannii ATCC17978 mutant appeared less or no pilus production. The E. coli JM109/rCsu pilus-producing clone significantly increased biofilm formation and adherence to A549 cells; however, the Csu-knockout mutant dramatically lost biofilm-making ability but, in contrast, increased adherence. Moreover, both of biofilm formation and adherence could be significantly inhibited by d-mannose and methyl-α-d-mannopyranoside in Csu pilus-producing E. coli JM109, whereas in A. baumannii ATCC17978, high concentration of carbohydrates was required for the inhibition, suggesting that Csu pilus is sensitive to d-mannose. CONCLUSION: This is the first study confirming that Csu pilus of A. baumannii belongs to mannose-sensitive type 1 pilus family and contributes to biofilm formation and bacterial adherence to human epithelial cells.

Use of dietary supplements containing polyvalent cations and antacids among people with HIV and its impact on viral suppression.

Dietary supplements and medications containing polyvalent cations can interact with integrase strand transfer inhibitors (INSTIs) and decrease exposure to INSTIs. In this cross-sectional study of 513 people with HIV (PWH) who were on stable antiretroviral therapy, 57.5% and 6.6% reported concurrent use of dietary supplements and antacids, respectively. In the multivariable analysis, the use of antacids, but not dietary supplements containing polyvalent cations, was associated with HIV viremia in PWH who received INSTI-based ART.

In vitro activities of piperacillin or cefoperazone alone and in combination with beta-lactamase inhibitors against gram-negative bacilli.

We investigated in vitro activities of piperacillin or cefoperazone alone and in combination with beta-lactamase inhibitors against Gram-negative bacilli. Piperacillin/tazobactam 8:1 lowered resistance for Escherichia coli, Serratia marcescens, Enterobactaer cloacae, Klebsiella pneumoniae and imipenem-susceptible Acinetobacter baumannii. When piperacillin was combined with sulbactam 2:1 or 4:1, resistance against E. coli, S. marcescens, E. cloacae, extended spectrum beta-lactamase (ESBL)-K. pneumoniae and A. baumannii were reduced. MIC90 of cefoperazone against S. marcescens, E. cloacae, ESBL-K. pneumoniae and A. baumannii were >128 mg/L. Addition of sulbactam 1:1 or 2:1 enhanced antimicrobial activities. Addition of sulbactam to piperacillin or cefoperazone enhanced antimicrobial activities of GNB.

Diversity of nasal microbiota and its interaction with surface microbiota among residents in healthcare institutes.

Nasal microbial communities may have crucial implications for human health, including for residents of healthcare institutes (HCIs). Factors that determine the diversity of nasal microbiota in HCIs remain unclear. Herein, we used 16S rRNA amplicon sequencing to investigate the relationship between nasal and surface microbiota in three HCIs. Participants were classified into a hospitalised or nonhospitalised group based on their most recent date of hospitalisation. A total of 88 nasal samples and 83 surface samples were analysed. Dysgonomonas and Corynebacterium were the most abundant taxa in the surface and nasal samples, respectively. Significant differences were discovered in microbiota diversity among HCIs when comparing the surface and nasal samples. Fifteen taxa were identified as present in all the surface and nasal samples. SourceTracker analysis revealed that the ventilation conditions of environment might be associated with the proportion of shared microbial communities between nasal and surface. Additionally, as compared with the nonhospitalised group, the hospitalised group had a higher proportion of surface microbiota in their nasal samples, which might lead to a higher risk of human-related microorganisms or pathogens colonising the nasal cavity. The data suggest that nasal bacterial diversity could be influenced by both health status and living environment. Our results therefore highlight the importance of the indoor environment for HCI residents.

Antimicrobial Susceptibility and Molecular Epidemiology of Proteus mirabilis Isolates from Three Hospitals in Northern Taiwan.

Of all the Proteus spp., Proteus mirabilis is the most common species identified in clinical specimens and is a leading agent of complicated urinary tract infection. This study was undertaken to understand the antimicrobial susceptibility, prevalence of antibiotic resistance genes, and molecular typing of P. mirabilis isolates collected from three hospitals in northern Taiwan. The results showed that the collected isolates of P. mirabilis were susceptible to most antibiotics except cefazolin and tigecycline. Many resistance genes were detected in the collected isolates, of which TEM genes were the most common. Resistance to third- or fourth-generation cephalosporins was related to the presence of at least one of the tested extended-spectrum ß-lactamase (ESBL) or AmpC genes. The presence of the VEB-1 gene seemed to be a good predictor for both cefepime and ceftazidime resistance, which was further supported by quantitative polymerase chain reaction results. Of the four imipenem-resistant P. mirabilis isolates, three isolates could hydrolyze imipenem by mass spectrometry analysis. Molecular typing by pulsed-field gel electrophoresis showed that the pulsotyping of the selected P. mirabilis isolates was heterogeneous. By analyzing the relationship of antimicrobial resistance and the presence of resistance genes, revision of the Clinical and Laboratory Standards Institute cefepime and ceftazidime MIC breakpoints for Enterobacteriaceae to predict ESBL producers might possibly be needed.

Invasive Haemophilus influenzae disease in adults in Taiwan.

BACKGROUND AND PURPOSE: Haemophilus influenzae is an important cause of invasive infection in infants and children, but it has been considered an uncommon cause of invasive disease in adults. We conducted a retrospective survey of invasive H. influenzae disease in adults in order to better understand the characteristics of clinical presentation and microbiology. METHODS: Patients older than 18 years with H. influenzae isolated from normally sterile sites, between July 1999 and June 2002 in a teaching hospital for adult patients were retrospectively analyzed. Data on demographics, clinical presentation, serotype, antibiotic susceptibility, and beta-lactamase production of H. influenzae isolates were analyzed. RESULTS: Fifteen patients were enrolled. The infectious diagnosis of invasive diseases comprised: pneumonia (5 patients), empyema (2), pelvic inflammatory disease (2), peritonitis (2), periorbital cellulitis with abscess formation (2), endophthalmitis (1) and primary bacteremia (1). Most patients were elderly with underlying illness. Of ten H. influenzae isolates available for analysis, two were serotype b and eight were nontypeable. Beta-lactamase production and ampicillin resistance were found in 6 H. influenzae isolates (5 nontypeable, and 1 type b). CONCLUSION: These data show H. influenzae disease in adults to be rare in Taiwan. Our limited number of cases suggest that nontypeable strains predominate in patients with invasive infection due to H. influenzae. Most patients had respiratory tract infections. Ampicillin resistance was found in more than one-half of H. influenzae isolates, and should be taken into consideration when antibiotics are prescribed on an empirical basis.

Clinical significance of Blastocystis hominis: experience from a medical center in northern Taiwan.

BACKGROUND AND PURPOSE: Blastocystis hominis is an intestinal protozoan. The pathogenic role of this organism in human beings is still controversial and has varied among reports from different geographic areas. The purpose of this study was to determine the clinical significance of B. hominis in northern Taiwan. METHODS: A total of 100 patients who had a positive B. hominis stool examination during the period April to December of 2001 were retrospectively identified from Taipei Veterans General Hospital. The demographic and clinical characteristics of these patients were reviewed from the medical records. RESULTS: All of the patients were adults. Fifty nine patients had more than one underlying diseases, including malignancies. Twenty one patients presented with fever and 10 patients had gastrointestinal symptoms, including diarrhea and/or abdominal pain. However, all of the patients had other conditions that might have contributed to the clinical presentation, and they improved without specific treatment for B. hominis. Furthermore, there were no significant differences in clinical symptoms and white blood cell count between patients with malignancy or diabetes mellitus and those without. Six patients had hypereosinophilia that could not be attributed to other causes. Among 34 patients who had a further stool examination within one year, B. hominis was undetectable in 31 patients (91.2%), despite their having no specific antiprotozoal treatment. CONCLUSIONS: The association of clinical symptoms and B. hominis could not be delineated from our study, even in immunocompromised patients. All of the patients improved without receiving any specific therapy. More studies from different areas are needed in order to delineate the clinical significance B. hominis.