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While molnupiravir (MOV) and nirmatrelvir–ritonavir (NMV-r) were developed for treatment of mild to moderate COVID-19 infection, there has been a lack of data on the efficacy among unvaccinated adult patients with chronic respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis. A territory-wide retrospective cohort study was conducted in Hong Kong to investigate the efficacy of MOV and NMV-r against severe outcomes of COVID-19 in unvaccinated adult patients with chronic respiratory diseases. A total of 3267 patients were included. NMV-r was effective in preventing respiratory failure (66.6%; 95% CI, 25.6–85.0%, p = 0.007), severe respiratory failure (77.0%; 95% CI, 6.9–94.3%, p = 0.039) with statistical significance, and COVID-19 related hospitalization (43.9%; 95% CI, −1.7–69.0%, p = 0.057) and in-hospital mortality (62.7%; 95% CI, −0.6–86.2, p = 0.051) with borderline statistical significance. MOV was effective in preventing COVID-19 related severe respiratory failure (48.2%; 95% CI 0.5–73.0, p = 0.048) and in-hospital mortality (58.3%; 95% CI 22.9–77.4, p = 0.005) but not hospitalization (p = 0.16) and respiratory failure (p = 0.10). In summary, both NMV-r and MOV are effective for reducing severe outcomes in unvaccinated COVID-19 patients with chronic respiratory diseases. [ABSTRACT FROM AUTHOR]

Typhoid fever is a notable disease in Hong Kong. We noticed two local cases of typhoid fever caused by Salmonella Typhi within a two-week period in late 2022, which had no apparent epidemiological linkage except for residing in the same region of Hong Kong. A phylogenetic study of Salmonella Typhi isolates from Hong Kong Island from 2020 to 2022 was performed, including a whole-genome analysis, the typing of plasmids, and the analysis of antibiotic-resistance genes (ARGs), to identify the dominant circulating strain and the spread of ARGs. A total of seven isolates, from six local cases and an imported case, were identified from positive blood cultures in two hospitals in Hong Kong. Five antibiotic-sensitive strains of genotype 3.2.2 were found, which clustered with another 30 strains originating from Southeast Asia. Whole-genome sequencing revealed clonal transmission between the two index cases. The remaining two local cases belong to genotype 2.3.4 and genotype 4.3.1.1.P1 (also known as the H58 lineage). The genotype 4.3.1.1.P1 strain has an extensively drug-resistant (XDR) phenotype (co-resistance to ampicillin, chloramphenicol, ceftriaxone, ciprofloxacin, and co-trimoxazole). Although the majority of local strains belong to the non-H58 genotype 3.2.2 with a low degree of antibiotic resistance, the introduction of XDR strains with the global dissemination of the H58 lineage remains a concern. [ABSTRACT FROM AUTHOR]

Healthcare-seeking behavior changed during the COVID-19 pandemic and might alter the epidemiology of pleural empyema. In this study, the incidence, etiology and outcomes of patients admitted for pleural empyema in Hong Kong in the pre-COVID-19 (January 2015–December 2019) and post-COVID-19 (January 2020–June 2022) periods were compared. Overall, Streptococcus pneumoniae was the predominant organism in <18-year-old patients, while Streptococcus anginosus, anaerobes and polymicrobial infections were more frequent in adults. In the post-COVID-19 period, a marked decline in the incidence of pleural empyema in children was observed (pre-COVID-19, 18.4 ± 4.8 vs. post-COVID-19, 2.0 ± 2.9 cases per year, p = 0.036), while the incidence in adults remained similar (pre-COVID-19, 189.0 ± 17.2 vs. post-COVID-19, 198.4 ± 5.0 cases per year; p = 0.23). In the post-COVID-19 period, polymicrobial etiology increased (OR 11.37, p < 0.0001), while S. pneumoniae etiology decreased (OR 0.073, p < 0.001). In multivariate analysis, clinical outcomes (length of stay, ICU admission, use of intrapleural fibrinolytic therapy, surgical intervention, death) were not significantly different in pre- and post-COVID-19 periods. In conclusion, an increase in polymicrobial pleural empyema was observed during the pandemic. We postulate that this is related to the delayed presentation of pneumonia to hospitals. [ABSTRACT FROM AUTHOR]

The epidemiology of patients with gastrointestinal colonization of carbapenem-resistant Acinetobacter baumannii (CRAB) has not been systematically analyzed. We aimed to analyze the incidence, risk factors, and clinical outcomes of patients with newly identified gastrointestinal colonization of CRAB in a healthcare region in Hong Kong, where a multi-pronged screening strategy for gastrointestinal colonization of CRAB, together with other multidrug-resistant organisms (MDROs), was conducted by collecting fecal specimens (rectal swab or stool) upon admission and during hospitalization. From 1 October 2015 to 31 December 2019, a total of 161,339 fecal specimens from 63,588 patients, 61,856 (97.3%) of whom were hospitalized patients, and 54,525 (88.1%) were screened upon admission, with 1309 positive for CRAB (2.4% prevalence). Among patients positive for CRAB in fecal specimens, 698 (53.3%) had newly detected gastrointestinal colonization of CRAB, giving an incidence of 10.03 per 10,000 patient admissions and constituting 2646 CRAB colonization days in the general wards. Excluding the 164 patients with co-colonization of other MDROs, 534 patients had gastrointestinal colonization with only CRAB, and 12.5% (67/534) developed symptomatic CRAB infections at a median of 61 days (range: 2 to 671 days), during prospective follow-up for 2 years. Compared with age- and sex-matched controls, patients being referred from residential care homes for the elderly, the presence of indwelling devices, use of beta-lactam/beta-lactamase inhibitors, carbapenems, and proton pump inhibitors in the preceding 6 months, and history of hospitalization in the past 6 months were significantly associated with gastrointestinal colonization with CRAB, as shown by multivariable analysis. Log-rank test showed that cases had significantly shorter survival duration than controls (p < 0.001). The adjusted hazard ratio of gastrointestinal colonization of CRAB was 1.8 (95% CI: 1.5–2.2; p < 0.001), as shown by Cox regression analysis. Whole-genome sequencing of eight patients with CRAB isolates in their blood cultures and rectal swabs during the same episode of hospitalization revealed ST-195 as the predominant type, as shown by multilocus sequencing type. Gastrointestinal colonization of CRAB poses a considerable challenge for infection prevention and control. [ABSTRACT FROM AUTHOR]

Background: Coronavirus Disease 2019 (COVID-19) led to pandemic that affected almost all countries in the world. Many countries have implemented border restriction as a public health measure to limit local outbreak. However, there is inadequate scientific data to support such a practice, especially in the presence of an established local transmission of the disease.Objective: To apply a metapopulation Susceptible-Exposed-Infectious-Recovered (SEIR) model with inspected migration to investigate the effect of border restriction as a public health measure to limit outbreak of coronavirus disease 2019.Methods: We apply a modified metapopulation SEIR model with inspected migration with simulating population migration, and incorporating parameters such as efficiency of custom inspection in blocking infected travelers in the model. The population sizes were retrieved from government reports, while the number of COVID-19 patients were retrieved from Hong Kong Department of Health and China Centre for Disease Control (CDC) data. The R0 was obtained from previous clinical studies.Results: Complete border closure can help to reduce the cumulative COVID-19 case number and mortality in Hong Kong by 13.99% and 13.98% respectively. To prevent full occupancy of isolation facilities in Hong Kong; effective public health measures to reduce local R0 to below 1.6 was necessary, apart from having complete border closure.Conclusions: Early complete travel restriction is effective in reducing cumulative cases and mortality. However, additional anti-COVID-19 measures to reduce local R0 to below 1.6 are necessary to prevent COVID-19 cases from overwhelming hospital isolation facilities. [ABSTRACT FROM AUTHOR]

A multi-pronged carbapenemase-producing Enterobacteriaceae (CPE) screening strategy was implemented in Hong Kong West healthcare network. Of 199,192 fecal specimens from 77,194 patients screening from 1 July 2011 to 30 June 2019, the incidence of CPE per 1000 patient admission significantly increased from 0.01 (2012) to 1.9 (2018) (p<0.01). With appropriate infection control measures, the incidence of nosocomial CPE per 1000 CPE colonization day decreased from 22.34 (2014) to 10.65 (2018) (p=0.0094). Exposure to wet market for purchasing raw pork (p=0.007), beef (p=0.017), chicken (p=0.026), and vegetable (p=0.034) for >3 times per week significantly associated with community acquisition of CPE. Strategic CPE control measures should be implemented in both the hospital and the community. [ABSTRACT FROM AUTHOR]

Background: Inappropriate antibiotic prescribing practices predispose to resistance emergence. Despite the inclusion of the topic in medical school curricula worldwide, it is uncertain whether newly graduated medical interns have confidence in proper antibiotic prescription.Objectives: This study aimed to explore the antibiotic prescribing behaviours of the medical interns in Hong Kong and their barriers to appropriate antibiotic prescription.Methods: Two focus groups were conducted among medical interns with training experiences in different public hospitals. Their prescribing behaviours and barriers were further examined with a questionnaire survey just before completion of internship.Results: Focus group interviews identified a variety of hospital workplace cultures, including inappropriate empirical prescriptions and dosages, interns' passive roles in prescribing antibiotics and varied guidelines between different departments. Defensive medicine and lack of clinical experience were other barriers encountered. The interns believed that the incorrect practice learnt would perpetuate in their minds and affect their future practice. The top barriers reported by the survey respondents were adaptation to prescription culture of different hospitals (93.5%), lack of experience in antibiotic prescription (88.3%), inadequate knowledge in the choice of antibiotics (85.7%) and compliance with the seniors' instructions (80.6%). However, some focus group participants perceived weaker barriers in paediatric departments which provided close monitoring of antibiotic use.Conclusions: Inadequate knowledge and low confidence in antibiotic prescription led to the passive role of medical interns in antibiotic prescription, predisposing to future inappropriate practice. Inconsistent guidelines and prescription cultures between different hospitals and departments might further exacerbate their barriers. [ABSTRACT FROM AUTHOR]

Oxacillin resistance mediated by mecA in Staphylococcus lugdunensis is emerging in some geographic areas. We evaluated cefoxitin disk diffusion (DD) and a new oxacillin agar (supplemented with 2 μg/ml oxacillin and 2% sodium chloride) screen for the detection of mecA -mediated resistance in S. lugdunensis. A total of 300 consecutive, non-duplicated clinical S. lugdunensis isolates from diverse sources in Hong Kong in 2019 were tested. The categorical agreement and errors obtained between cefoxitin DD test, oxacillin agar screen and mecA PCR were analyzed. Isolates with discordant results were further tested by MIC, penicillin binding protein 2a (PBP2a) assays, population analysis and molecular typing. PCR showed that 62 isolates were mecA -positive and 238 isolates were mecA -negative. For cefoxitin DD results interpreted using S. aureus / S. lugdunensis breakpoints, the categorical agreement (CA) for two brands of Muller-Hinton agars, MH-II (Becton Dickinson) and MH-E (bioMérieux) were both 96.0%; MEs were both 0%; and VMEs were 19.4 and 12.9%, respectively. The new oxacillin agar reliably differentiated mecA -positive and mecA -negative isolates (100% CA) without any ME or VME results. The 8 isolates with false susceptibility in the cefoxitin DD testing had cefoxitin and oxacillin MICs in the susceptible range. The isolates showed heterogeneous oxacillin resistance with resistant subpopulations at low frequencies. All had positive PBP2a results and were typed as sequence type 27/SCC mec V. The findings highlight the inability of cefoxitin DD and MIC tests for reliable detection of some mecA -positive S. lugdunensis isolates. [ABSTRACT FROM AUTHOR]

Toilet hygiene is an important preventive measure for infectious diseases, including severe acute respiratory syndrome (SARS) and COVID-19. This study explored public's opinions on improving toilet environment and hygiene practices in Hong Kong. A mixed-method approach was applied. We conducted 4 focus groups plus 3 individual interviews among the Hong Kong Chinese, followed by a questionnaire survey with 300 respondents recruited from various districts. Difference in response distributions between groups with different demographics was tested by Pearson χ2 test. Instead of advocating for advanced toilet facilities, respondents were mostly concerned about basic hygiene issues. Malfunctioning facilities resulting from poor toilet management, such as clogged toilets, stained facilities, and problematic flushing systems, were most cited as barriers to toilet hygiene practices. Three quarters of the survey respondents expressed concerns over worn and poorly maintained toilets, shortage of janitors, and cleansing supplies. However, respondents who were older (P <.001), less educated (P <.001), and had lower income (P =.001) were significantly more likely to find hygiene conditions in public toilets satisfactory. The findings reflected the substandard of the current provisions as a developed city in Asia. Enhanced efforts by the government to maintain basic toilet supplies and facilities is the key to improving public compliance to toilet hygiene practices. [ABSTRACT FROM AUTHOR]

Background: Public toilets are a common transmission vector of infectious diseases due to environmental contamination. Research on Chinese people's hygiene practices in public lavatories are lacking. This study examined Chinese people's hygiene practices in public lavatories in Hong Kong.Methods: We conducted qualitative interviews and a self-administered questionnaire survey with local residents from June 2016 to April 2018. Four focus group discussions and three individual interviews informed the design of the questionnaire. We recruited interviewees and survey respondents via social service centers. The interviews and questionnaire focused on the public's daily practices and hygiene behaviors in public toilets. Content analysis of qualitative data was conducted. Multivariable logistic regressions were used to examine the association between age and toilet hygiene behaviors.Results: Our qualitative component revealed a range of handwashing practices, from not washing at all, washing without soap, to washing for a longer time than instructions. Other toilet use practices were identified, such as not covering toilet lid before flushing and stepping on toilet seats due to dirtiness, and spitting into toilet bowls or hand basin. Totally, 300 respondents completed the questionnaire. Among them, 212 (70.9%) were female and 246 (86.1%) were aged 65 or below. More than two thirds always washed hands with soap (68.7%) and dried hands with paper towels (68.4%). Up to 16.2% reported stepping on toilet seats and 43.9% never covered the toilet lid before flushing. Over one fourth (26.4%) spit into squat toilets/ toilet bowl. Regression analyses showed that the elderly group were less likely to report stepping on toilet seats (adjusted odds ratio, AOR = 0.17, 95%CI 0.03-0.88), flushing with the toilet lid closed (AOR = 0.40, 0.16-0.96), but more likely to spit into squat toilets/ toilet bowl (AOR = 4.20, 1.50-11.74).Conclusions: Hong Kong Chinese's compliance to hygiene practices in public toilets is suboptimal. Stepping on toilet seat is a unique Chinese practice due to the dirtiness of toilet seats. Spitting practices may increase the risk of airborne infectious diseases and need improvement. Measures are needed to improve toilet hygiene behaviors, including public education campaigns and keeping toilet environment clean. [ABSTRACT FROM AUTHOR]

In 2017, we identified a Clostridium difficile strain HKCD4 that caused community-acquired fulminant colitis in a previously healthy child. Phylogenetically, it belonged to clade 2, sequence type 67 and was resistant to fluoroquinolone and tetracycline. The strain was pathogenicity locus and binary toxin positive. It has a mutation in the trehalose repressor treR leading to the L172I substitution that was previously reported in the epidemic ribotype 027 lineage. HKCD4 has a tcdB sequence that shared very high identities with 3 highly virulent reference strains. It has a CpG depleted genome that is characteristic of hypervirulent C. difficile. The emergence of ST67 lineage with molecular feature of hypervirulence in the community is concerning and emphasizes the need for full characterization of strains causing severe disease in patients without classical risk factors. [ABSTRACT FROM AUTHOR]

Objectives: To characterize blaIMP-4-carrying plasmids originating from inpatients in Hong Kong.Methods: Sixteen blaIMP-4-carrying plasmids identified among Enterobacteriaceae (nine Escherichia coli, four Klebsiella pneumoniae, two Citrobacter freundii and one Enterobacter cloacae) recovered from 15 patients were characterized. The isolates, collected during January 2010 to December 2013, were retrospectively investigated by plasmid sequencing, molecular and fitness studies.Results: The blaIMP-4-carrying plasmids belonged to the IncN ST7 lineage (∼50 kb). Twelve of the 16 plasmids were epidemiologically linked to seven different regions in China. Alignment of the complete plasmid sequences showed identical plasmid backbones and two highly similar resistance regions, each carrying one of two resistance genes (blaIMP-4 and qnrS1). The blaIMP-4 was detected in a class 1 integron (containing blaIMP-4 and intron Kl.pn.13) that is part of an IS6100-IS26 transposon-like structure. The nine E. coli carrying the epidemic plasmid belonged to multiple multilocus STs (six ST542, one ST131, one ST657 and one ST3177). Fitness assays performed on E. coli J53 recipients showed that the presence of the epidemic plasmid did not have a significant biological cost.Conclusions: This study identified a blaIMP-4-carrying IncN ST7 plasmid disseminated among multiple enterobacterial species originating from patients with epidemiological links to different regions in China. [ABSTRACT FROM AUTHOR]

The emergence of multidrug resistance in Bacteroides fragilis , especially the phylogenetic lineage carrying the carbapenemase gene cfiA , represents an increasing threat to human health. However, knowledge on the diversity of the multidrug-resistant strains and the genetic elements carrying the antibiotic resistance genes (ARGs) remains limited. The objective of the study was to describe the resistome in cfiA -positive B. fragilis. A collection of cfiA -positive B. fragilis from diverse human (8 bacteremias, 15 wound infections) and animal (2 chickens, 2 pigs, 6 dogs, 3 cats) sources in Hong Kong, 2015–2017 was analysed by whole genome sequencing. In the 36 isolates, 13 distinct ARGs (total number 83, median 2, range 0–7 per isolate) other than cfiA were detected. ARGs encoding resistance to aminoglycosides, β-lactams, macrolides, sulphonamides and tetracyclines were carried by CTn 341 -like, CTn Hyb -like, Tn 5220 -like, Tn 4555 -like and Tn 613 -like transposons and were detected in phylogenetically diverse isolates of different host sources. Only few ARGs encoding resistance to metronidazole and tetracyclines were localized on plasmids. In two chicken isolates, a novel transposon (designated as Tn 6994) was found to be involved in the dissemination of multiple ARGs mediating resistance to multiple antibiotics, including metronidazole and linezolid that are critically important for treatment of anaerobic infections. In mating experiments, Tn 6994 and the associated phenotypic resistance could be transferred to Bacteroides nordii recipient. This study illustrates the importance of transposons in the dissemination of ARGs in the cfiA -positive division of B. fragilis. One Health approach is necessary to track the dissemination of ARGs. [ABSTRACT FROM AUTHOR]

We collected nasal, axilla, and groin swabs from 252 adult patients from 2 nephrology centers in Hong Kong. Staphylococcus lugdunensis carriage was detected in 51.6% patients (groin, 39.3%; axilla, 19.8%; nose, 17.9%). The carriage rates of methicillin-sensitive S . lugdunensis and methicillin-resistant S . lugdunensis (MRSL) were 46.0% and 8.3%, respectively. Independent risk factors for S . lugdunensis carriage included male sex (odds ratio [OR], 4.4), hemodialysis (OR, 2.2), and aged 18–50 years (OR, 2.4). The isolates belonged to 10 pulsotype clusters (n = 129) and 8 singletons (n = 8). All MRSL and most gentamicin- and tetracycline-resistant strains were found in a predominating sequence type 3 clone, designated HKU1, which accounted for 51.8% of all colonizing S . lugdunensis strains. The 21 MRSL isolates had SCC mec type V (n = 18), type IV (n = 2), and type I (n = 1). The finding highlights the potential for dissemination of multidrug resistance through successful S . lugdunensis clones. [ABSTRACT FROM AUTHOR]

This study assessed pneumococcal carriage in the early periods after routine use of 13-valent pneumococcal conjugate vaccine (PCV13) in Hong Kong. Nasopharyngeal swabs were obtained from 1110 children (<5 years) admitted with acute illness during September 2010–August 2013. Pneumococcal carriage rate was 13.5% in unvaccinated children, 14.1% in children who had ≥1 PCV dose and 15.3% in children who had ≥3 PCV doses. Nonv-PCV13 serotypes comprised 56.4% of all isolates. The most common serogroup/types were 15 (15A, 5.1%; 15B, 10.3%; 15C, 9.6%; 15F, 0.6%), 19F (17.9%), 6A (7.1%) and 6C (7.1%). Carriage of serogroup 15 was more common among vaccinated children (4.1% versus 0.6%, P = 0.033). Molecular typing revealed that expansion of several clones (clonal complex, CC63, CC199, CC1262, CC3397) was responsible for the increase in serogroup 15. Almost all CC63 and CC3397 isolates were nonsusceptible to both penicillin and erythromycin. The finding highlights the emergence of serogroup 15 following PCV13 use. [ABSTRACT FROM AUTHOR]

Abstract: This study assessed the temporal changes in the molecular epidemiology of bacteremic Escherichia coli isolates producing CTX-M-14 in Hong Kong. Blood isolates from 1996 to 1998 (period 1, n = 50) and 2007 to 2008 (period 2, n = 117) were investigated by molecular methods. CTX-M–type ESBL was carried by 98.2% (164/167) of the isolates. In both periods, the CTX-M-9 group and CTX-M-14 allele were the predominant ESBL type. The major clones were found to change from ST68 and ST405 in period 1 to ST131, ST69, and ST12 in period 2. Among 65 CTX-M-14–producing plasmids investigated further, 54 had the FII replicon. Replicon sequence typing and plasmid polymerase chain reaction–restriction fragment length polymorphism showed that 79.6% (43/54) of the FII plasmid subset was similar to the completely sequenced plasmid, pHK01 (human urine, Hong Kong, 2004). These pHK01-like plasmids were found to have spread to the major clones (ST68, ST405, and ST131) and multiple singleton isolates of all 4 phylogenetic groups. [Copyright &y& Elsevier]

Summary: Objectives: To investigate the prevalence and molecular epidemiology of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) nasal carriage in children. Methods: We collected nasal and nasopharyngeal swabs from 2211 children aged 2–5 years attending 79 day care centers (DCCs) and 113 kindergartens (KGs) in all 18 geographical districts in Hong Kong. Results: The overall carriage rates of S. aureus and MRSA were 27.6% (95% confidence interval [CI], 24.8–28.5%) and 1.3% (95% CI, 0.8–1.8%), respectively. Molecular typing (staphylococcal cassette chromosome mec [SCCmec], sequence type [ST], clonal cluster [CC]) showed that all the 28 MRSA isolates had SCCmec IV (n = 13) or V (n = 15) including 12 isolates with community-associated-MRSA genotypes (ST59-IV/V, ST30-IV and ST88-V), 10 isolates with healthcare-associated-MRSA genotypes (ST45-IV/V, CC5-IV and ST630-V) and six isolates with novel genotypes (ST10-V and CC1-IV). Spa typing indicated that there was some within and between DCCs/KGs transmission of certain MRSA and methicillin-sensitive S. aureus strains but this was not extensive. Conclusion: Our findings indicate the potential for DCCs to be a reservoir for emerging MRSA genotypes and highlight the need to enhance education and infection control measures to reduce their cross-transmission in this population. [Copyright &y& Elsevier]

Summary: Objectives: The risk factors for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection were not well understood. The objective of this study was to identify risk factors associated with CA-MRSA infection in Hong Kong. Methods: We carried out a matched case control study. Cases and controls were recruited from 14 acute public hospitals in Hong Kong. One control was individually matched to one case based on sex, age, admission date and ward location. We interviewed each case and control by telephone using a standard questionnaire. We used a conditional logistic regression model for multivariate analysis. Results: We successfully recruited 127 pairs of matched case and control. We found that sharing of personal items with other persons had a higher risk of CA-MRSA infection (Adjusted matched odds ratio [aOR]: 4.71, 95% confidence interval [CI] 1.43–15.59). On the other hand, patients who had frequent hand washing practice (aOR: 0.21, 95%CI 0.06–0.72) and those who reported history of acne (aOR: 0.12, 95%CI 0.02–0.74) had a lower risk of CA-MRSA infection. Conclusions: We concluded that sharing of personal items with other persons is a risk factor for CA-MRSA infection while frequent hand washing is a protective factor against the infection. [Copyright &y& Elsevier]

Abstract: This study assessed the changes in serotype distribution and antibiotic resistance of Streptococcus pneumoniae isolates in children before and after introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in Hong Kong. Nasopharyngeal specimens were collected from 1978 and 2211 children (ages, 2 to 6 years) attending day care centers or kindergartens in period 1 (1999–2000) and period 2 (2009–2010), respectively. Carriage of PCV7 serotypes decreased from 12.8% to 8.6% (P < 0.01). The relative contribution of PCV7 serotypes 14 and 18C had decreased, whereas that for non-PCV7 serotypes 19A, 6A, 6C, 23A, and 15B had increased. In period 2, PCV7 penetration rate (at least 1 dose) for children aged 2, 3, 4, and 5 years was 43%, 35.7%, 26.7%, and 20.4%, respectively. In multivariate analysis, PCV7 use was the only independent variable associated with fewer PCV7 serotype carriages (odds ratio 0.5; P = 0.001). In period 2, high rates of dual penicillin/erythromycin nonsusceptibility were found in serotypes 6B (77.3%), 14 (100%), 19F (100%), 23F (78%), 19A (75%), 6A (87.8%), 6C (59.3%), and 23A (78.9%). [Copyright &y& Elsevier]

Abstract: This study analyzed 828 isolates causing invasive pneumococcal disease (IPD) before (1995–2001, n =265) and after (2007–2009, n =563) the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in Hong Kong. In children <5 years, serotype 14 had declined (36–15.7%, P <0.01) while 19A had increased (0–12.9%, P <0.01) in the before and after periods, respectively. In children aged <5 years, the proportion of PCV7 serotypes declined from 89.5% to 65.7% (72.8% if included cross protection against 6A) with time but that of PCV13 serotypes remained stable (91.4–93.2%). In elderly ≥65 years, 9V and 23F decreased from 3.8% to 0.3% (P =0.01) and from 18.9% to 7.4% (P <0.01), respectively while 7F increased significantly from 0% to 4.1% (P =0.04) over the same periods. Among isolates from aged <5 years, dual penicillin/erythromycin resistance increased from 44.1% to 64.2% (P =0.01). The types that often had dual penicillin/erythromycin resistance were 6B, 14, 19F, 23F, 6A and 19A. The emergence of serotype 19A was associated with expansion of sequence type 320. [Copyright &y& Elsevier]

Abstract: A study was conducted to determine the prevalence of the 2 newly described types, 6C and 6D, among pneumococcal isolates collected in Hong Kong before availability of the 7-valent pneumococcal conjugate vaccine. A total of 154 serogroup 6 isolates obtained from nasopharynx (n = 106), blood (n = 22), respiratory (n = 24), and cerebrospinal fluid (CSF) (n = 2) during 1995 to 2001 were analyzed by polymerase chain reaction typing. Five nasopharyngeal and 2 sputum isolates were found to belong to 6C and 6D, respectively. The isolates were genetically diverse, but one 6C and two 6D isolates exhibited some clonal relationship. Phylogenetic analysis of the wchA–wciNβ–wciO nucleotide sequences showed that the Hong Kong 6C/6D isolates had 2 allelic profiles, which were more closely related to 6C/6D isolates from Fijian and Korea than were those from Brazil and the United States. However, all of the wciP gene sequences for both Hong Kong and non-Hong Kong isolates clustered together: 6C isolates with the wciP-9 allele and 6D isolates with the wciP-5 allele. In conclusion, the prevalence of the 2 newly described serotypes was low before the era of the pneumococcal conjugate vaccine. Nonetheless, results from the molecular studies indicated that the evolution of the capsular genes have involved complex pathways. [ABSTRACT FROM AUTHOR]

Summary: Objectives: To assess whether vancomycin MIC creeps among blood methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered from 5 hospitals in Hong Kong from 1997 to 2008. Methods: Blood cultures MRSA isolates from 1997 to 1999 (period 1), 2004 (period 2) and 2006–2008 (period 3) were retrieved. Etest method was used to determine their vancomycin MIC. The genotypic features were determined by PCR and sequencing. Results: 247 blood MRSA isolates were studied. The vancomycin MIC were 0.375, 0.5, 0.75 and 1 mg/L for 15 (6.1%), 68 (27.5%), 89 (36%) and 75 (30.4%) isolates, respectively. There was an increase in the percentage of isolates with an MIC=1mg/L from 10.4% (5/48) during period 1 to 21.6% (8/37) during period 2 and 38.3% (62/162) during period 3 (period 1 vs. period 3, P <0.001). Molecular typing showed that this was due to increased percentages of clonal cluster (CC) 8/SCCmec III/IIIA (agr group I), CC45/SCCmec IV/V (agr group IV) and other minor clones with elevated MIC over time. Conclusion: This study found vancomycin MIC creep among blood MRSA isolates over time. As elevated MIC within the susceptible range may reduce vancomycin efficacy, clinical laboratories should adopt methods with the required precision to accurately determine MICs. [Copyright &y& Elsevier]

The article reports a colistin-resistant Enterobacteriaceae carrying the mcr-1 gene among patients in Hong Kong, China. It says that colistin belongs to the last line of bactericidal antimicrobial drugs active against multidrug-resistant gram-negative bacteria such as carbapenemase-producing Enterobacteriaceae and carbapenem-resistant Acinetobacter baumannii.

Abstract: This study assessed the susceptibility trend of methicillin-resistant Staphylococcus aureus (MRSA) in 5 Hong Kong hospitals from 1995 to 2005. Representative blood isolates were characterized to correlate the changes in resistance phenotypes with the clonal nature of MRSA. The prevalence of multisusceptible (MS) MRSA, defined by sensitivity to gentamicin, co-trimoxazole, and fusidic acid, was found to increase dramatically from <2% in 1995 to 1997 to 4.5% to 5.8% in 1998 to 1999 and remained at around 10% thereafter. Isolation of MS-MRSA was significantly associated with older age, convalescent care, and blood culture source. Molecular typing showed that the increasing isolation of MS-MRSA was associated with the spread of ST45/Staphylococcus cassette chromosome mec (SCCmec) IV or V with spa t1768, t1857, or t1081. Other features of the ST45 strains are as follows: agr4, capsular type 8, and Panton–Valentine leukocidin (PVL) negative. Two other epidemic clones, EMRSA-16 (ST36/SCCmec II) and CC398 (ST1277/SCCmec V), were detected as sporadic isolates for the first time in Hong Kong. [Copyright &y& Elsevier]

Pneumococcal conjugate vaccines (PCVs) successfully decreased the incidence of invasive pneumococcal disease in children. However, many countries have reported serotype replacement and a rebound in diseases from non-vaccine serotypes. Here, we report the genomic investigation of a Streptococcus pneumoniae strain M215 that caused severe meningoencephalitis in an infant in 2019. The strain was assigned to serotype 24F using the bioinformatic pipeline SeroBA and pneumococcal type specific anti-sera. The strain was resistant to cotrimoxazole from mutations in both folA and folP genes. It was susceptible to penicillin and other non-β-lactam antibiotics. Phylogenetically, it belongs to Global Pneumococcal Sequence Cluster (GPSC) 6 and multi-locus sequence type 162. A total of 38 virulence genes were detected in the genome of M215. Upon comparison of the profile of virulence genes, GPSC6 but not non-GPSC6 strains of serotype 24F and related serotypes were found to possess the major virulence determinant, pilus islet-1, comprising genes encoding sortases (srtB, srtC, srtD), pilus proteins (rrgA, rrgB and rrgC) and one transcriptional regulator (rlrA), which was previously described to be characteristic feature of international clones in the pre-PCV era. In our locality, this represented the first detection of serotype 24F and GPSC6/ST162 causing serious pneumococcal disease. The emergence of the non-vaccine serotype 24F GPSC6/ST162 lineage with molecular feature of high virulence is concerning and emphasizes the need for full characterization of strains causing severe disease. [ABSTRACT FROM AUTHOR]

Abstract: This prospective study assessed the epidemiology of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) among patients with purulent skin and soft tissue infections (SSTIs) in Hong Kong. Among 298 patients with SSTIs, 10.4% (13/125) of all S. aureus isolates and 5% (12/241) of all abscesses were attributed to pvl-positive CA-MRSA. Overall, 77% and 69.9% of CA-MRSA and methicillin-sensitive S. aureus (MSSA) were susceptible to erythromycin, 77% and 74.8% to clindamycin, 100% and 97.1% to minocycline, and 100% and 98.1% to rifampin, respectively. Filipino ethnicity was the only clinical and epidemiologic factor significantly associated with CA-MRSA infection (odds ratio, 14.8; 95% confidence interval, 3.3–70.0; P < 0.001). Pulsed-field gel electrophoresis analysis showed that 6 CA-MRSA isolates belonged to the ST30-HKU100 clone, 5 belonged to the ST59-HKU200 clone, and 1 was singleton. Features of HKU100 isolates include SCCmec type IV, agr3, spa t019, and pan-susceptibility to non–β-lactam antibiotics. In contrast, HKU200 isolates are characterized by having SCCmec type IV or V, agr4, spa t437, and variable non–β-lactam susceptibility profiles. The major CA-MRSA spa types were shared by a minority of the MSSA. [Copyright &y& Elsevier]

Abstract: This study evaluated the clinical and epidemiologic features of individuals with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Hong Kong from January 2004 through December 2005. Twenty-four episodes of skin and soft tissue infections and 1 episode of meningitis due to CA-MRSA were identified. CA-MRSA infections or carriage was found in 6 (13%) of 46 household contacts. A total of 29 isolates were analyzed by the Staphylococcus cassette chromosome mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. In addition, polymerase chain reaction detection of the genes encoding Panton-Valentine leukocidin was also carried out. It was observed that 24 had SCCmec IV/IVA and 5 had SCCmec V, and 23 were pvl positive. PFGE analysis clustered all except 1 isolate into 3 pulsed-field types (PFTs), HKU100 through HKU300. The HKU100 isolates had genotype ST30-IV identical to the Southwest Pacific clone. The HKU200 isolates belonged to ST59-V and were multiresistant, including an ermB-mediated macrolide resistance trait, which is characteristic of the predominant CA-MRSA clone in Taiwan. The HKU300 isolates had unique features (ST8, Panton–Valentine leukocidin negative, and SCCmec IVA) typical of CA-MRSA in Japan. In conclusion, CA-MRSA has a propensity to spread within families. Our findings showed that CA-MRSA strains in Hong Kong have diverse genetic backgrounds. [Copyright &y& Elsevier]

An editorial is provided in which the authors discuss public health efforts to control the coronavirus disease 2019 (COVID-19) pandemic in Hong Kong, China, including through the mandatory quarantine of travelers, hand hygiene and the wearing of surgical masks. The role that hand hygiene and medical masks play in the prevention of COVID-19 virus transmission is discussed.

The article examines the prevalence of Escherichia coli producing extended-spectrum Β-lactamases (ESBL) in Hong Kong, China, based on the database of microbiology from a healthcare region from 2000 to 2010. The database was extracted and analyzed using linear regression in order to assess changes in the burden of Escherichia coli bacteremia. Variables such as hospital admissions and patient-days are also considered in this assessment.

The article discusses a study to determine the effect of implementing the new Clinical and Laboratory Standards Institute (CLSI) imipenem susceptibility breakpoints for Enterobacteriaceae in Hong Kong, China. It was noted that applying the new CLSI criteria drastically changed the susceptibility rates for some isolate groups. The reduction in imipenem susceptibility rate was dramatic for Proteus spp., Enterobacter spp., Providencia spp. and Morganella spp.

The article discusses a study which examined the presence of the O25-sequence type 131 clonal group among Escherichia coli isolates from a prospective cohort of female outpatients with cystitis in Hong Kong, China. 28.8% of patients had a history of urinary tract infection. Information on the phylogenetic group distribution of the isolates is provided. Results of the study showed that O25b-ST131 isolates were accounted for 45.7% of ciprofloxacin-resistant patients.

This retrospective study analyzed the susceptibility levels of Bacteroides fragilis group (BFG) in a hospital-based laboratory where disk diffusion test (DDT) was routinely performed. Isolates non-susceptible to imipenem and metronidazole by DDT were further investigated using a gradient method. The DDT and MIC susceptibility data of clindamycin, metronidazole, moxifloxacin and imipenem obtained on Brucella blood agar for 1264 non-duplicated isolates during 2020–2021 were analyzed. Species identification was obtained by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and 16S rRNA sequencing. Interpretative agreement of DDT results using the 2015 EUCAST tentative and 2021 CA-SFM breakpoints was compared against MIC as the reference. The dataset included 604 B. fragilis (483 division I, 121 division II isolates), 415 non- fragilis Bacteroides , 177 Phocaeicola and 68 Parabacteroides. Susceptibility rates for clindamycin (22.1–62.1%) and moxifloxacin (59.9–80.9%) were low and many had no inhibition zones. At the EUCAST and CA-SFM breakpoints, 83.0 and 89.4% were imipenem-susceptible, and 89.6% and 97.4 were metronidazole-susceptible. MIC testing confirmed 11.4% and 2.8% isolates as imipenem-non-susceptible and metronidazole-resistant, respectively. Significant numbers of false-susceptibility and/or false-resistance results were observed at the CA-SFM breakpoint but not the EUCAST breakpoint. Higher rates of imipenem and/or metronidazole resistance were detected in B. fragilis division II, B. caccae, B. ovatus, B. salyersiae, B. stercoris and Parabacteroides. Co-resistance to imipenem and metronidazole was detected in 3 B. fragilis division II isolates. The data demonstrated emerging BFG resistance to several important anti-anaerobic antibiotics and highlights the importance of anaerobic susceptibility testing in clinical laboratories to guide therapy. • Antimicrobial resistance in Bacteroides fragilis group is emerging. • Antimicrobial susceptibilities of 1264 B. fragilis group were analyzed. • Clindamycin and moxifloxacin resistance rates were high. • Imipenem resistance rate was 11.4%. • Metronidazole resistance rate was 2.8%. [ABSTRACT FROM AUTHOR]

To compare the phylogeny of cfiA -positive Bacteroides fragilis isolates from diverse human and animal sources. Complete genome sequences were obtained from 42 cfiA -positive B. fragilis isolates (Hong Kong, 2015–2017) and additional 24 genomes deposited in the GenBank (multiple countries, 1985–2019) were included. The genomic clusters were constructed using PopPUNK. The CfiA alleles and polymorphism in the cfiA locus were analyzed in silico. The 66 isolates were grouped into 12 genomic clusters (BFSC-1 to 12). Human infection isolates were distributed in diverse clusters, being many of them common to fecal isolates from both human and animals. Thirteen CfiA alleles including 2 novel ones were identified. CfiA-1 (n = 28) is the predominating allele, following by CfiA-13 (n = 8), CfiA-4 (n = 7) and CfiA-14 (n = 6). The other CfiA alleles were identified in 1–3 isolates. Six patterns of gene context were identified in the regions flanking cfiA locus. No consistent association between genomic clusters and CfiA alleles could be detected. Similarly, markedly elevated imipenem MIC was linked to the integration, immediately upstram of cfiA of an IS element but not the CfiA allele or gene context. The phylogeny of cfiA -positive B. fragilis isolates causing human diseases was diverse and overlaped with those from human and animal carriage. • The genomic phylogeny of 66 cfiA -positive Bacteroides fragilis isolates was analyzed. • The isolates were grouped into 12 PopPUNK-based genomic clusters. • Clinical isolates shared the same genome clusters as carriage isolates from human and animals. • No correlation between CfiA allele and genome cluster was identifed. • The phylogeny of emerging cfiA -positive B. fragilis is diverse. [ABSTRACT FROM AUTHOR]