Multicenter surveillance of the epidemiology of gram-negative bacteremia in Japan

Effects of meropenem supply restriction: A multicenter retrospective study

BACKGROUND

In Japan, the supply of one generic meropenem product was restricted from August 2022 to March 2023.

OBJECTIVE

To determine the effects of meropenem (MEPM) restriction.

METHODS

We conducted a multicenter retrospective study comparing antimicrobial use, bacteremia mortality, and drug-resistant bacteria detected before the restriction of MEPM (control period), from September 2021 to February 2022, and after the restriction of MEPM (MEPM supply restriction period), from September 2022 to February 2023, in five institutions.

RESULTS

The number of carbapenem days of therapy (DOTs) were decreased in all five institutions. Fourth-generation cephalosporin DOTs increased in all facilities, and piperacillin/tazobactam DOTs increased in four facilities. The 30-day and 90-day mortality rates were significantly higher during the MEPM supply restriction period than those during the control period. Moreover, survival time was significantly shorter during the MEPM supply restriction period than that during the control period. Multivariable analysis revealed that MEPM supply restriction, age >80 years, Pitt Bacteremia Score ≥4, platelet count <10 × 104/μL, serum albumin level <2.5 g/dL, and methicillin-resistant Staphylococcus aureus bloodstream infection were independent risk factors for 30-day mortality. The detection rates of carbapenem-resistant Pseudomonas aeruginosa and Enterobacteriaceae did not differ significantly between the two periods.

CONCLUSIONS

MEPM supply restriction decreased the use of carbapenems and increased the use of other broad-spectrum antimicrobial agents, which worsened the prognosis of bacteremia. Overall, carbapenems are important drugs for the treatment of infectious diseases and are difficult to replace in unforeseen situations such as drug supply outages.

Global mapping of antibiotic resistance rates among clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis

INTRODUCTION

Infections caused by Stenotrophomonas maltophilia are clinically important due to its intrinsic resistance to a broad range of antibiotics. Therefore, selecting the most appropriate antibiotic to treat S. maltophilia infection is a major challenge.

AIM

The current meta-analysis aimed to investigate the global prevalence of antibiotic resistance among S. maltophilia isolates to the develop more effective therapeutic strategies.

METHOD

A systematic literature search was performed using the appropriate search syntax after searching Pubmed, Embase, Web of Science and Scopus databases (May 2023). Statistical analysis was performed using Pooled and the random effects model in R and the metafor package. A total of 11,438 articles were retrieved. After a thorough evaluation, 289 studies were finally eligible for inclusion in this systematic review and meta-analysis.

RESULT

Present analysis indicated that the highest incidences of resistance were associated with doripenem (97%), cefoxitin (96%), imipenem and cefuroxime (95%), ampicillin (94%), ceftriaxone (92%), aztreonam (91%) and meropenem (90%) which resistance to Carbapenems is intrinsic. The lowest resistance rates were documented for minocycline (3%), cefiderocol (4%). The global resistance rate to TMP-SMX remained constant in two periods before and after 2010 (14.4% vs. 14.6%). A significant increase in resistance to tigecycline and ceftolozane/tazobactam was observed before and after 2010.

CONCLUSIONS

Minocycline and cefiderocol can be considered the preferred treatment options due to low resistance rates, although regional differences in resistance rates to other antibiotics should be considered. The low global prevalence of resistance to TMP-SMX as a first-line treatment for S. maltophilia suggests that it remains an effective treatment option.

Antimicrobial use and combination of resistance phenotypes in bacteraemic Escherichia coli in primary care: a study based on Japanese national data in 2018

BACKGROUND

Antimicrobial use (AMU) in primary care is a contributing factor to the emergence of antimicrobial-resistant bacteria. We assessed the potential effects of AMU on the prevalence of a combination of resistance phenotypes in bacteraemic Escherichia coli in outpatient care settings between primary care facilities ('clinics') and hospitals.

METHODS

Population-weighted total AMU calculated from the national database was expressed as DDDs per 1000 inhabitants per day (DID). National data for all routine microbiological test results were exported from the databases of a major commercial clinical laboratory, including 16 484 clinics, and the Japan Nosocomial Infections Surveillance, including 1947 hospitals. AMU and the prevalence of combinations of resistance phenotypes in bacteraemic E. coli isolates were compared between clinics and hospitals.

RESULTS

The five most common bacteria isolated from patients with bacteraemia were the same in clinics, outpatient settings and inpatient settings in hospitals, with E. coli as the most frequent. Oral third-generation cephalosporins and fluoroquinolones were the top two AMU outpatient drugs, except for macrolides, and resulted in at least three times higher AMU in clinics than in hospitals. The percentage of E. coli isolates resistant to both drugs in clinics (18.7%) was 5.6% higher than that in hospitals (13.1%) (P < 10-8).

CONCLUSIONS

Significant AMU, specifically of oral third-generation cephalosporins and fluoroquinolones, in clinics is associated with a higher prevalence of E. coli isolates resistant to both drugs. This study provides a basis for national interventions to reduce inappropriate AMU in primary care settings.

Current viewpoint on the epidemiology of nonfermenting Gram-negative bacterial strains

PURPOSE OF REVIEW

This article aims to review the epidemiology of nonfermenting Gram-negative bacilli (NFGNB) based on recent literature reports, particularly, of the less common, but with emerging clinical significance species.

RECENT FINDINGS

The reported frequency of multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa is increasing, with very significant variability, however, between different countries. Apart from the major NFGNB, that is, A. baumannii and P. aeruginosa, already recognized as of critical importance healthcare risks, several other NFGNB genera have been increasingly associated with diverse severe infections, such as Stenotrophomonas maltophilia, Burkholderia spp., Elizabethkingia spp., Chryseobacterium spp., Achromobacter spp., Alcaligenes spp., Sphingomonas spp., Shewanella spp. and Ralstonia spp., among others.

SUMMARY

The exploration of the epidemiology, as well as the pathogenic potential of the of the less frequent, but emerging and increasingly reported NFGNB, is crucial, not only for immunocompromised patients, but also for critically ill patients without overt immunosuppression. As we are heading fast towards a postantibiotic era, such information would contribute to the optimal antimicrobial management, that is, providing prompt, appropriate antimicrobial coverage when needed and, at the same time, avoiding overuse and/or inappropriate use of antimicrobial therapy. Also, it would help to better understand their transmission dynamics and to develop effective prevention strategies.

Epidemiological analysis and antimicrobial susceptibility profile of Gram-negative bacilli that cause bacteremia in Japan

We investigated the epidemiology and antimicrobial susceptibility profiles of seven major Gram-negative bacilli (Escherichia coli, Klebsiella spp., Enterobacter spp., Pseudomonas aeruginosa, Acinetobacter spp., Stenotrophomonas maltophilia, and Bacteroides spp.) that caused bacteremia in Japan. We collected clinical information and isolates from patients aged 20 years or older who developed bacteremia during a year at three Japanese university hospitals and performed microbiological examination. In total, 628 cases were included, half of which were caused by E. coli (315 isolates). P. aeruginosa (56 isolates) was isolated most frequently among non-fermenting bacteria and 33 Bacteroides spp. were isolated. Mortality rates were the highest for P. aeruginosa (7-day, 16.1%; 30-day, 26.8%). The 7- and 30-day mortality rates ranged 3.8-9.0% and 8.3-17.6%, respectively, for Enterobacterales, and they were 15.2% each for Bacteroides spp. Regarding antimicrobial resistance, Enterobacterales and Acinetobacter spp. showed susceptibility to carbapenems and amikacin (98.0-100.0%). The susceptibility rates to ceftolozane/tazobactam ranged 82.4-99.0% for Enterobacterales and 92.9% for P. aeruginosa. More than 30.0% of E. coli isolates were resistant to fluoroquinolone. Extended-spectrum β-lactamase (ESBL) producers were found in 21.0% of E. coli and approximately 80% of those were resistant to fluoroquinolones. The susceptibility of the 33 Bacteroides spp. to carbapenems, ampicillin/sulbactam, and piperacillin/tazobactam was 100.0%. Among the ESBL producers, blaCTX-M group 9 was the major subgroup in E. coli (77.3%), and blaCTX-M group 1 was detected in 18.2% of E. coli and 50.0% of Klebsiella spp. Continuous surveillance is needed to understand the epidemiology and consider appropriate therapeutic strategies.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2019-2020: General view of the pathogens' antibacterial susceptibility

The trends and prevalence of antimicrobial susceptibility of pathogens vary by country, region, and time. Long-term regular surveillance is required to investigate trends in the antimicrobial resistance of various isolated bacterial pathogens. We report the results of a nationwide surveillance on the antimicrobial susceptibility of bacterial respiratory pathogens in Japan conducted by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology. The isolates were collected from clinical specimens obtained from adult patients who visited a collaborating medical facility between June 2019 and December 2020 and were diagnosed with respiratory tract infections by a physician. Antimicrobial susceptibility testing was performed in a centralized laboratory according to the methods recommended by the Clinical and Laboratory Standards Institute. Susceptibility testing was performed for 932 strains (201 Staphylococcus aureus, 158 Streptococcus pneumoniae, 6 S. pyogenes, 136 Haemophilus influenzae, 127 Moraxella catarrhalis, 141 Klebsiella pneumoniae, and 163 Pseudomonas aeruginosa) collected from 32 facilities in Japan. The proportions of methicillin-resistant S. aureus and penicillin-resistant S. pneumoniae were 35.3% and 0%, respectively. In H. influenzae, 16.2% and 16.9% were β-lactamase-producing ampicillin resistant and β-lactamase-negative ampicillin resistant, respectively. Extended-spectrum β-lactamase-producing K. pneumoniae accounted for 5.0% of all K. pneumoniae infections. Carbapenemase-producing K. pneumoniae and multi-drug-resistant P. aeruginosa with metallo-β-lactamase were not detected in this study. This surveillance will be a useful reference for treating respiratory infections in Japan and will provide evidence to enhance the appropriate use of antimicrobial agents.

Treatment outcomes and its associated factors among pneumonia patients admitted to public hospitals in Harar, eastern Ethiopia: a retrospective follow-up study

OBJECTIVE

Although there is a high risk of drug resistance, empiric treatment is a common approach for pneumonia management. In this respect, it is relevant to know treatment outcomes of patients with pneumonia. This study aimed to assess treatment outcomes and its associated factors among pneumonia patients treated at two public hospitals in Harar, eastern Ethiopia.

DESIGN

Retrospective follow-up study.

SETTING

Jugal General Hospital and Hiwot Fana Specialised University Hospital in Harar, eastern Ethiopia.

PARTICIPANTS

Patients admitted and treated for pneumonia in the two public hospitals in eastern Ethiopia between April 2020 and April 2021.

PRIMARY OUTCOME

The primary outcome was unfavourable treatment outcome (died or transferred to intensive care unit) for pneumonia patients.

RESULTS

A total of 693 patients with pneumonia were included in the study. 88 (12.7%) of these patients had an unfavourable treatment outcome, which included 14 (2%) transfers to the intensive care unit and 74 (10.7%) deaths. Patients with comorbidity (adjusted OR, AOR=2.96; 95% CI: 1.47 to 5.97) and with clinical features including abnormal body temperature (AOR=4.03; 95% CI: 2.14 to 7.58), tachycardia (AOR=2.57; 95% CI: 1.45 to 4.55), bradypnoea or tachypnoea (AOR=3.92; 95% CI:1.94 to 7.92), oxygen saturation below 90% (AOR=2.52; 95% CI:1.37 to 4.64) and leucocytosis (AOR=2.78, 95%, CI:1.38 to 5.58) had a significantly increased unfavourable treatment outcome.

CONCLUSION

We found that nearly one out of eight patients with pneumonia had unfavourable treatment outcomes. It was considerably high among patients with comorbidities and apparent abnormal clinical conditions. Therefore, taking into account regionally adaptable intervention and paying close attention to pneumonia patients admitted with comorbidity and other superimposed abnormal conditions might help improve the treatment outcomes of these populations.

Targeted literature review of the burden of extraintestinal pathogenic Escherichia Coli among elderly patients in Asia Pacific regions

BACKGROUND

Extraintestinal Pathogenic Escherichia coli (ExPEC) is a leading cause of invasive disease, including bacteremia and sepsis. Invasive ExPEC disease (IED) has the potential to complicate the clinical treatment of other conditions and is associated with an increased mortality, hospitalization, and worse outcomes. Older adults and individuals with comorbid conditions are at higher risk of IED. ExPEC is of particular concern in the Asia Pacific region due to aging populations and rising antimicrobial resistance.

OBJECTIVES

This study aimed to synthesize most recent data on the epidemiology, clinical and economic burden of IED in the elderly/high risk populations in China, Japan, South Korea, Taiwan, and Australia.

METHODS

A targeted literature review was conducted using Embase, Medline, as well as local scientific databases. We included studies published in English and local languages published from January 1, 2010 to October 7, 2020 that were relevant to the research objectives. Studies were narratively synthesized.

RESULTS

A total of 1,047 studies were identified and 34 of them were included in this review. ExPEC accounted for 46.0% (1,238/2,692) of bacteria-related invasive diseases in patients aged above 60 years in South Korea, followed by China (44.4% (284/640)), Taiwan (39.0% (1,244/3,194)), and Japan (18.1% (581/3,206)), while Australia reported ExPEC out of all pathogens (54.7% (4,006/7,330)) in general adults. Comorbidities such as diabetes or cancer were common in these patients. Studies reported increases in length-of-stay, and in-hospital 30-day all-cause mortality related to ExPEC associated bacteremia was between 9% to 12%. From a cost perspective, a 3-fold increase in sepsis-associated cost was reported in South Korea between 2005 and 2012. In Australia, antimicrobial resistance contributed to an additional cost of AUD $5.8 million per year (95% uncertainty interval [UI], $2.2-$11.2 million) in the treatment of bloodstream infections (BSIs).

CONCLUSION

ExPEC was a major cause of blood stream infection across China, Japan, South Korea, Taiwan, and Australia. Both the clinical and economic burden associated to ExPEC infections as well as the antimicrobial resistance observed in the elderly call for preventive and curative actions in these regions.

Distribution of extraintestinal pathogenic Escherichia coli O-serotypes and antibiotic resistance in blood isolates collected from patients in a surveillance study in Japan

INTRODUCTION

Invasive extraintestinal pathogenic Escherichia coli (ExPEC) disease (IED), characterised by sepsis and bacteraemia, is a major global healthcare concern worsened by emerging multidrug resistant (MDR) strains. The development of multivalent prophylactic vaccines targeting E. coli strains of IED-associated O-serotypes could address this. A better understanding of O-serotype distribution is required for this purpose. Here, we characterised O-serotype prevalence and drug resistance among ExPEC bacteraemia isolates in Japan.

METHODS

E. coli blood isolates from patients aged ≥60 years with bacteraemia were obtained from a retrospective surveillance study in Japan (2015-2017). O-serotyping was performed by agglutination; for isolates non-typeable by agglutination, O-genotyping was performed. Antimicrobial susceptibility was evaluated by broth microdilution using a 21-antibiotic panel. The frequency of drug resistant (DR) isolates was evaluated by antimicrobial susceptibility testing.

RESULTS

Of 401 ExPEC bacteraemia isolates evaluated, the most prevalent O-serotype (≥1%) was O25 (28.7% [n = 115]), followed by O1 (14.2% [n = 57]), O2 (8.5% n = 34]), O6 (5.5% [n = 22]), O75, O18, O13, O16, O15, O4, O46/O134, O86, O8 and O83 (each <5% prevalence). These 14 O-serotypes accounted for 81.5% of isolates collected. In total, 19% (n = 77) of isolates were DR ≥ 3, of which 59.7% were O25. Fluoroquinolone-resistance among all and O25 isolates was most prevalent (35.7% and 84.3%, respectively). Almost all (98%) isolates identified as O25 were of subtype O25B.

CONCLUSIONS

E. coli serotype O25B showed the highest prevalence and highest multidrug resistance among ExPEC bacteraemia isolates from patients ≥60 years in Japan. Our data may inform development of multivalent glycoconjugate vaccines to prevent IED.

The two faces of cyanide: an environmental toxin and a potential novel mammalian gasotransmitter

Cyanide is traditionally viewed as a cytotoxic agent, with its primary mode of action being the inhibition of mitochondrial Complex IV (cytochrome c oxidase). However, recent studies demonstrate that the effect of cyanide on Complex IV in various mammalian cells is biphasic: in lower concentrations (nanomolar to low micromolar) cyanide stimulates Complex IV activity, increases ATP production and accelerates cell proliferation, while at higher concentrations (high micromolar to low millimolar) it produces the previously known (‘classic’) toxic effects. The first part of the article describes the cytotoxic actions of cyanide in the context of environmental toxicology, and highlights pathophysiological conditions (e.g., cystic fibrosis with Pseudomonas colonization) where bacterially produced cyanide exerts deleterious effects to the host. The second part of the article summarizes the mammalian sources of cyanide production and overviews the emerging concept that mammalian cells may produce cyanide, in low concentrations, to serve biological regulatory roles. Cyanide fulfills many of the general criteria as a ‘classical’ mammalian gasotransmitter and shares some common features with the current members of this class: nitric oxide, carbon monoxide, and hydrogen sulfide.

Current situation of carbapenem-resistant Enterobacteriaceae and Acinetobacter in Japan and Southeast Asia

In the recent years, issues related to drug-resistant bacteria have evolved worldwide, and various countermeasures have been taken to control their spread. Among a wide variety of drug-resistant bacterial species, carbapenem-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Acinetobacter baumannii (CRAb), are those for which countermeasures are particularly important. Carbapenems are the last resort antibiotics for any bacterial infection; therefore, infectious diseases caused by these drug-resistant bacteria are difficult to treat. In the case of CRE, since carbapenemases responsible for carbapenem resistance are mostly encoded on transmissible plasmids, it is known that susceptible bacteria can easily become carbapenem-resistant by transfer of plasmids between Enterobacteriaceae. In addition, Enterobacteriaceae are common bacterial species found in the guts of animals, including humans. Acinetobacter is ubiquitously isolated in the environment. Due to these characteristics, it is quite difficult to prevent the intrusion of multi-drug resistant pathogens in hospitals. Therefore, effective countermeasures should be developed and utilized against such dangerous pathogens based on molecular epidemiological analyses. In this review, there are also some examples presented on how to manage to monitor and control those troublesome drug-resistant bacteria conducted in Japan and Southeast Asia.