In vitro activity and clinical efficacy of macrolides, cefoperazone-sulbactam and piperacillin/piperacillin-tazobactam against Bordetella pertussis and the clinical manifestations in pertussis patients due to these isolates: A single-centre study in Zhejiang Province, China

Laboratory, epidemiological and clinical characteristics of pertussis in children and close contacts: a cross-sectional study

PURPOSE

To investigate the epidemiological and clinical characteristics of pertussis in children and close contacts.

METHODS

Nasopharyngeal swabs and blood samples of clinically suspected children with pertussis and their close contacts from 2018 to 2022 were collected for pathogen detection of Bordetella pertussis. Questionnaires were designed to investigate the basic information and infection status of pertussis children cases and their close contacts. Descriptive epidemiological analysis was performed on the results.

RESULTS

1229 confirmed children cases of pertussis were collected and infants < 1 year old were the most affected (77.7%). Etiological data were collected from 587 close contacts of 269 confirmed cases and the infection rate was high (24.4%). The positive detection rate of parents, especially mothers, was significantly higher than that of other groups (32.2% vs. 18.4%, P < 0.001); The rates of misdiagnosis or missed diagnosis in pertussis children (92.2%) and close contacts (99.8%) were very high, and the distribution of symptoms between pertussis children and their close contacts was different (χ2 = 535.328, P < 0.001); The vast majority of pertussis children (84.0%) were diagnosed with upper respiratory tract infection or trachea/bronchitis while 91.0% of close contacts did not seek medical attention (χ2 = 685.373, P < 0.001).

CONCLUSION

Infants < 1 year old are at high risk in pertussis. Pertussis infection in close contacts of confirmed children is underestimated. Caregivers who are positive for pertussis but missed or misdiagnosed seriously may be a main source of pertussis infections in children. Adjusting the current pertussis immunization strategy in China is necessary.

Coagulation dysfunction events associated with echinocandins: a real-world study from FDA adverse event reporting system (FAERS) database

BACKGROUND

Echinocandins belong to the fourth generation of antifungals, and there are no systematic studies on their risk in coagulation dysfunction; this study will predict the risk of coagulation dysfunction of echinocandins using the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.

METHOD

Data from January 2004 to March 2024 were obtained from FAERS. We examined the clinical characteristics of the coagulation dysfunction events and conducted disproportionality analysis by using reporting odds ratios (ROR) to compare echinocandins with the full database.

RESULTS

There were 313 reports of coagulation dysfunction related to echinocandins as the primary suspect (PS) drug. The median time to incident for coagulation dysfunction was 3 (interquartile range [IQR] 1-9) days. Compared to triazoles and polyenes, echinocandins have a stronger signal (ROR 3.18, 95%CI 2.81-3.51, p < 0.01) of coagulation dysfunction. Compared to caspofungin and micafungin, anidulafungin has a stronger signal (ROR 6.84, 95%CI 4.83-9.70, p < 0.01). The strongest signal corresponding to disseminated intravascular coagulation (DIC), platelet count decreased, thrombocytopenia, gastrointestinal haemorrhage, cerebral haemorrhage, pulmonary haemorrhage and thrombotic thrombocytopenic purpura (TTP) is micafungin (ROR 27.19, 95%CI 18.49-39.98), micafungin (ROR 3.50, 95%CI 2.36-5.19), anidulafungin (ROR 9.75, 95%CI 5.22-18.19), micafungin (ROR 3.17, 95%CI 2.02-4.97), micafungin (ROR 4.95, 95%CI 2.81-8.72), caspofungin (ROR 20.76, 95%CI 11.77-36.59), micafungin (ROR 20.43, 95%CI 8.49-49.14), respectively.

CONCLUSIONS

For coagulation dysfunction, we found stronger signals for echinocandins than triazoles and polyenes, and stronger signals for anidulafungin than micafungin and caspofungin. Coagulation parameters should be closely monitored while using the respective drugs.

Severe problem of macrolides resistance to common pathogens in China

With the widespread use of macrolide antibiotics in China, common pathogens causing children's infections, such as Streptococcus pneumoniae, Streptococcus (including Group A streptococcus, Group B streptococcus), Staphylococcus aureus, Bordetella pertussis, and Mycoplasma pneumoniae, have shown varying degrees of drug resistance. In order to provide such problem and related evidence for rational use of antibiotics in clinic, we reviewed the drug resistance of common bacteria to macrolides in children recent 20 years.

Alterations of Growth, Biofilm-Forming, and Gene Expression of Bordetella pertussis by Antibiotics at Sub-Minimal Inhibitory Concentrations

Bordetella pertussis is the primary agent of the acute respiratory disease pertussis. It has been reported that the disease has recently become more common, especially in adults and adolescents, and adaptation of the pathogen is thought to have an important influence on the recurrence of the disease. This study aims to determine the effect of erythromycin, azithromycin, and trimethoprim-sulfamethoxazole used in the treatment of pertussis on the virulence gene expressions (prn, ptxS1, fhaB), biofilm-forming and growth of B. pertussis. In this study, the minimal inhibitory concentration (MIC) values of azithromycin and erythromycin in B. pertussis local strain Saadet were determined to be 0.09 μg/mL and 0.3 μg/mL, respectively. However, the Tohama-I and Saadet strains were resistant to trimethoprim-sulfamethoxazole (MIC>32 μg/mL). The biofilm-forming of the Saadet strain decreased with the increase in antibiotic doses. It was observed that 1/32MIC erythromycin and 1/32MIC azithromycin upregulated the expression of fhaB in Tohama-I, whereas the expression of ptxS1 and prn significantly decreased in sub-MICs of erythromycin. In the Saadet strain, only ptxS1 was highly expressed at 1/16MIC azithromycin and erythromycin (p>0.05). This is the first study to investigate the effect of sub-MIC antibiotics on the expression of virulence genes and biofilm-forming of B. pertussis.

Macrolide Resistance in Bordetella pertussis: Current Situation and Future Challenges

Pertussis is a highly contagious respiratory infection caused by Bordetella pertussis bacterium. The mainstay of treatment is macrolide antibiotics that reduce transmissibility, shorten the duration of symptoms and decrease mortality in infants. Recently, the macrolide resistance of B. pertussis has been reported globally but is especially widespread in mainland China. In this review, we aim to summarise the current understanding of the epidemiology, resistance mechanisms and clinical implications of B. pertussis macrolide resistance. Since the first appearance of macrolide-resistant B. pertussis in Arizona, USA, in 1994, only sporadic cases have been reported outside China. In certain parts of China, on the other hand, up to 70-100% of the recent clinical isolates have been found to be macrolide resistant. Reasons for macrolide resistance being centred upon China during the last decade can only be speculated on, but the dominant B. pertussis lineage is different between China and most of the high-income countries. It seems evident that efforts to increase awareness, guide molecular epidemiological surveillance and carry out systematic screening of B. pertussis positive samples for macrolide resistance should be implemented globally. In addition, practices to improve the clinical care of infants with pertussis caused by resistant strains should be studied vigorously.

A Cross-Sectional Study Revealing the Emergence of Erythromycin-Resistant Bordetella pertussis Carrying ptxP3 Alleles in China

Background

Previous limited studies have identified that Bordetella pertussis (B. pertussis) isolates circulating in China possess distinct molecular features and high rates of erythromycin-resistance (ER). Their evolution and potential impact on the prevention and control of global pertussis are worthy of attention.

Methods

The present cross-sectional study involved 311 non-duplicate and unrelated B. pertussis strains isolated from Chinese children from 2017 to 2019. Their antimicrobial susceptibilities were assessed using both E-test strips and Kirby-Bauer (KB) disk diffusion methods. Seven virulence-related genes (ptxA, ptxC, ptxP, prn, fim2, fim3, and tcfA2) and the A2047G mutation in the 23S rRNA gene were detected by PCR. Based on the susceptibilities and genotypes, 50 isolates were selected for multi-locus variable-number tandem-repeat analysis (MLVA) typing and whole-genome sequencing.

Results

A total of 311 B. pertussis strains were isolated from children with a median age of 4 months (interquartile range: 2–9 months). Strains carrying the ptxP1 allele were more frequent (84.9%, 264/311), were always ER (except for one strain), and were mainly related to ptxA1/ptxC1/prn1 alleles (99.6%, 263/264). The remaining 47 (15.1%) strains carried the ptxP3 allele, mainly harboring the ptxA1/ptxC2/prn2 alleles (93.6%, 44/47), and were sensitive to erythromycin (except for two strains). The two ER-ptxP3 isolates were first identified in China, belonged to MT27 and MT28 according to MLVA, and were classified into sub-lineage IVd by phylogenetic analysis of their genome sequences. This sub-lineage also includes many strains carrying the ptxP3 allele spreading in developed countries. For each tested antimicrobial, the susceptibilities judged by KB disks were consistent with those determined by E-test strips.

Conclusion

The present results reveal that B. pertussis strains with the ptxP1-ER profile still dominate in China, and a few strains carrying the ptxP3 allele have acquired the A2047G mutation in the 23S rRNA gene and the ER phenotype. The surveillance of the drug susceptibility of B. pertussis is necessary for all countries, and the KB disk method can be adopted as a screening test.

Epidemiological and clinical characteristics of pertussis in children and their close contacts in households: A cross-sectional survey in Zhejiang Province, China

BACKGROUND

Despite the expanded immunization programs, the "re-emergence of pertussis" has become a global concern in recent years. At present, the prevalence of pertussis in China is seriously underestimated, and the role of close contact on the disease spreading in children remains unclear.

OBJECTIVES

Our study aimed to investigate pertussis's epidemiological and clinical characteristics in children and their close contacts in households, as well as the antimicrobial resistance of Bordetella pertussis (B. pertussis) in Zhejiang Province, China.

METHODS

We have collected the retrospective and prospective data of children who were suspected of pertussis and their close contacts in households from January 1, 2018, to December 31, 2020, in the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. Nasopharyngeal swabs were collected and cultured for B. pertussis. Antibiotics susceptibility test was determined by using E-test methods. Clinical information was collected from the medical records systems.

RESULTS

A total of 350 index patients and their 946 family members (close contacts in households) from 350 families were recruited. B. pertussis strains were isolated from 130 (37.1%) index patients and 116 (12.3%) close contacts. 37 index patients had negative culture results for B. pertussis while their close contacts were positive. A higher positive rate was found in female adults than that in male adults (16.3% vs. 5.1%, P < 0.01). The positive rate in index patients from multi-child families was significantly higher than that from one-child families (51.7% vs. 37.7%, P < 0.05). 53.3% of the pertussis patients were under 6 months of age. 98 (75.4%) isolates had MICs ≥ 256 mg/L to erythromycin, azithromycin, and clindamycin, and 127 (97.7%) had MICs < 0.016 mg/L to piperacillin.

CONCLUSION

Infants under 6 months of age are at high risk of pertussis, and close contacts in households are prone to cluster infection. Culture for B. pertussis both in children and their close contacts contributes to improving the diagnosis rate of pertussis in children. Isolates of B. pertussis in China are highly resistant to macrolides.

Retrospective analysis of bacterial culture-confirmed pertussis cases in Beijing Children's hospital from 2014 to 2019 reveals prevention and control of the grim situation in mainland China

BACKGROUND

Our study aims to explore the epidemiological features of children with bacterial culture-confirmed pertussis visiting Beijing Children's Hospital, China.

METHODS

From 2014 through 2019, patients with suspected pertussis coming from mainland China provided nasopharyngeal swabs and bacterial culture that was subsequently cultivated.

RESULTS

During the study period, 6956 children with suspected pertussis from 30 different administrative provinces of mainland China were investigated, of which 1494 cases (21.5%) had positive B. pertussis culture. The number of pertussis cases increased year-on-year, from 122 in 2014 to 279 in 2019. Of the confirmed cases, 38.2% and 26.8% were identified in the summer and autumn, respectively. The age distribution of children with pertussis showed that 77.2% were <12 months old, including 56.0% <6 months old. Only thirteen B. parapertussis isolates and one B. bronchiseptica isolates were collected in the present samples.

CONCLUSIONS

The present culture-confirmed cases reveal the severe epidemic situation of pertussis spreading over the whole country and mainly affecting the infants. It is necessary to set up hospital-based surveillance with reliable laboratory methods to promote clinical awareness and to monitor the disease.

[Research advances in the treatment strategies for severe pertussis in children]

At present, effective antibiotics and comprehensive symptomatic/supportive treatment as early as possible are mainly used for the treatment of severe pertussis in clinical practice. However, some children with severe pertussis have unsatisfactory response to commonly used drugs and treatment measures in the intensive care unit and thus have a high risk of death. Studies have shown that certain treatment measures given in the early stage, such as exchange transfusion, may help reduce deaths, but there is still a lack of uniform implementation norms. How to determine the treatment regimen for severe pertussis and improve treatment ability remains a difficult issue in clinical practice. This article reviews the advances in the treatment of severe pertussis, in order to provide a reference for clinical treatment and research.

Effect of Macrolides and β-lactams on Clearance of Bordetella pertussis in the Nasopharynx in Children With Whooping Cough

OBJECTIVE

The purpose of the current study is to investigate the bactericidal effect of macrolides and β-lactams on Bordetella pertussis (B. pertussis) in the nasopharynx and provide guidance for treating macrolides-resistant B. pertussis infections.

METHODS

Patients with whooping cough was diagnosed by culture of nasopharynx swabs between January 2016 to December 2018. B. pertussis was identified using specific antisera against pertussis and parapertussis. Drug susceptibility test was carried out using the E-test method. The clearance of B. pertussis in nasopharynx at 7 and 14 days into and posttreatment with macrolides, and β-lactams was compared.

RESULTS

A total of 125 B. pertussis samples were collected from patients who received single antibiotic treatment. Among those isolates, 62.4% (78/125) had high resistance with minimum inhibitory concentrations greater than 256 mg/L for erythromycin and azithromycin. The MIC90 of piperacillin, cefoperazone-sulbactam, meropenem, ampicillin, ceftriaxone, ceftazidime and trimethoprim-sulfamethoxazole for these isolates was <0.016, 0.094, 0.094, 0.19, 0.19, 0.25 and 0.75 mg/L, respectively. The clearance rate with β-lactams treatment (68.8%, 44/64) was significantly higher than that with macrolides treatment at 14 days posttreatment (50.8%, 31/61) (χ2 = 4.18, P = 0.04). Macrolides had a better clearance rate at 7 days posttreatment than β-lactams (χ2 = 4.49, P = 0.03) for macrolides-sensitive isolates and a worse clearance rate for macrolides-resistant isolates.

CONCLUSION

B. pertussis isolates had a high-resistant rate for macrolides in our study. Macrolides are the first choice for treating pertussis caused by macrolides-sensitive strains, and some β-lactams such as piperacillin should be considered as alternative antibiotics for treatment of macrolides-resistant B. pertussis infection.

Pharmacotherapy for Bordetella pertussis infection. I. A synthesis of laboratory sciences

There is considerable history and practice experience both with laboratory susceptibility testing for Bordetella pertussis and clinical treatment. This two-part narrative review provides a synthesis of the laboratory and clinical sciences as they apply to this bacterium and the clinical consequences of treating infection. It is generally held that antibiotic susceptibility testing for B. pertussis is not sufficiently standardised, but there has not been an urgent need to consolidate the same given the lack global experience with major resistance profiles. Experience in China, however, has provided concern for high-level macrolide resistance. The nature of and frequency of such resistance has raised the bar for reconsideration of susceptibility testing given that first-line treatment may be regionally compromised. Disk diffusion and Etest susceptibility testing can be recommended for screening resistance among individual isolates of B. pertussis and on an ad hoc manner. Disk diffusion, Etest and/or critical agar dilution testing can be recommended for large-scale studies. Standards for inoculum, growth atmosphere, timing of interpretation, preferred testing media and controls can be extrapolated from the publications to date. Such methods should be able to detect high-level resistance to several antibiotics, but especially macrolides. Concern for intermediate-susceptible categories requires consideration as well as the correlation with bacteriological and clinical outcomes. Provisional standards can be applied at this time, and modification or fine-tuning of any such standards are open to future investigation.

Pharmacotherapy for Bordetella pertussis infection. II. A synthesis of clinical sciences

Despite the plethora of studies that have examined laboratory susceptibility testing for Bordetella pertussis, assessments of treatment have lagged far behind both in quality and quantity. Macrolides and trimethoprim/sulfamethoxazole historically served the needs of both treatment and prevention, albeit there is still controversy about the degree of protection measured both bacteriologically and clinically. As high-level macrolide resistance has emerged in some geographic regions and since macrolides have been the mainstay of therapy, alternative antibiotics need to be defined for pertussis. In vitro susceptibility testing suggests the potential for several alternatives to macrolides, including trimethoprim/sulfamethoxazole, specific β-lactam agents, chloramphenicol, some quinolones and possibly some tetracyclines. For the latter antibiotics, more clinical studies for treatment and prophylaxis are required in to order to establish bacteriological-clinical correlates for outcome. In the interim, if the clinical circumstances mandate the use of proposed interim alternatives to macrolides, outcomes should be assessed with test of cure by culture, since genetic amplification technologies do not discriminate bacterial viability. Whereas there may be debate in regard to using placebo or macrolides as the controls for alternative antibiotic therapy in geographies where most B. pertussis isolates are antibiotic-susceptible, both placebo and macrolide controls should be assessed along with alternative antibiotics in well-designed controlled studies in regions pressured by macrolide resistance. Outcomes of clinical response and epidemiological patterns of disease should continue to be monitored given the degree of macrolide resistance that is emerging.

The global prevalence ptxP3 lineage of Bordetella pertussis was rare in young children with the co-purified aPV vaccination: a 5 years retrospective study

Background

The global prevalent ptxP3 strains varies from about 10% to about 50% of circulating B. pertussis population in different areas of China.

Methods

To investigate the difference of vaccination status between different genotypes in the circulating B. pertussis after 10 years of acellular pertussis vaccine (aPV) used in China. The nasopharyngeal swabs and isolates of B. pertussis from these patients were used to perform genotyping of antigen genes. We use antibiotic susceptibility test against erythromycin and sequencing methods for site 2047 of 23S rRNA to determine the resistance status.

Results

The ptxP1 allele with erythromycin resistant (ER) B. pertussis infection (total of 449 subjects) consisted of 84.70 to 96.70% from 2012 to 2016 in this study. Vaccinated with co-purified aPV was found in 133(133/403,33.0%), 1(1/9,11.1%) and 2(2/21,9.5%) in ptxP1/fhaB3-ER, ptxP1/fhaB2-ES and ptxP3/fhaB2-ES B. pertussis infected children each, which showed a significant difference (χ² = 6.87, P = 0.032).

Conclusions

The ptxP3-ES B. pertussis was rare while the ptxP1-ER B. pertussis was steadily increased in Xi’an, China from 2012 to 2016, where co-purified aPV was prevalent used. This pose a hypothesis that the co-purified aPV might protect against ptxP3 strains more efficient, which generated a rare chance for ptxP3 strains to be under the antibiotic pressure and further developed to be erythromycin resistance. A further cohort study and the mechanisms of the additional antigen proteins of co-purified aPV protected against B. pertussis should be consideration.

Molecular Epidemiology of Bordetella pertussis

Although vaccination has been effective, Bordetella pertussis is increasingly causing epidemics, especially in industrialized countries using acellular vaccines (aPs). One factor behind the increased circulation is the molecular changes on the pathogen level. After pertussis vaccinations were introduced, changes in the fimbrial (Fim) serotype of the circulating strains was observed. When bacterial typing methods improved, further changes between the vaccine and circulating strains, especially among the common virulence genes including pertussis toxin (PT) and pertactin (PRN) were noticed. Moreover, development of genome based techniques including pulsed-field gel electrophoresis (PFGE), multiple-locus variable number tandem repeat analysis (MLVA) and whole-genome sequencing (WGS) have offered a better resolution to monitor B. pertussis strains. After the introduction of aP vaccines, B. pertussis strains that are deficient to vaccine antigens, especially PRN, have appeared widely. On the other hand, antimicrobial resistance to first line drugs (macrolides) against B. pertussis is still low in many countries and therefore no globally evaluated antimicrobial susceptibility test values have been recommended. In this review, we focus on the molecular changes in the bacteria, which have or may have affected the past and current epidemiology of pertussis.