Antimicrobial resistance, prevalence of resistance genes, and molecular characterization in intestinal Bacteroides fragilis group isolates

Kouhsari, Ebrahim; Mohammadzadeh, Nima; Kashanizadeh, Mohammad Ghasem; Saghafi, Mohammad Mehdi; Hallajzadeh, Masoumeh; Fattahi, Azam; Ahmadi, Alireza; Niknejad, Farhad; Ghafouri, Zahra; Asadi, Arezoo; Nasrabadi, Mohammad Reza Boujary

doi:10.1111/apm.12943

Cited by 21 publications

(12 citation statements)

References 38 publications

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“…It is well known that the mechanism of carbapenem resistance within B.fragilis is mianly mediated by cfiA gene and the upstream IS element is required. In this study, the positive rate of cifA gene of carbapenem resistant B. fragilis reached up to 38.9%, which is obviously higher than other reports published recently[7,17]. It is noteworthy that B. fragilis strains with cfiA gene can easily converted to be resistant ones by the effects of its upstream IS element[18], which implies that a larger group of patients maybe a potential reservoir of carbapenem resistant B. fragilis producers, who are colonized or infected by B. fragilis with silent cfiA gene.…”

contrasting

confidence: 65%

Higher prevalence of multi-antimicrobial resistant Bacteroides spp. strains isolated at a tertiary teaching hospital, China

Wang¹,

Han²,

Shen³

et al. 2019

Preprint

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Background: The antimicrobial resistance of Bacteroides spp. isolates is reported to be increasing among different districts around the world, and few reports found that multi-antimicrobial resistant strains emerged. However, less is known about the prevalence of multi-antimicrobial resistant isolates in China, especially for carbapenem resistance. Methods: Bacteroides spp. clinical strains were isolated from inpatients at a 3000 bed tertiary teaching hospital , and were identified by MALDI-TOF MS and VITEK-2 anaerobes and corynebacterium (ANC) card. Broth microdilution method was employed to detect the antimicrobial sensitivities of Bacteroides spp. isolates and PCR method was used to detect the resistance genes, including cfxA, cepA, cfiA, ermF and nim. The upstream insertion sequence (IS) element of cfiA gene was further detected and verified. Results: Among 115 Bacteroides spp. strains enrolled in this study, 80 isolates were Bacteroides fragilis and 35 isolates were non-Bacteroides fragilis. The total resistance rates of 115 Bacteroides spp. isolates to ampicillin/sulbactam, amoxicillin/clavulanic, cefoxitin, piperacillin, piperacillin/tazobactam, moxifloxacin, clindamycin, metronidazole, imipenem and meropenem were 22.6%, 19.6%, 3.5%, 27.8%, 8.7%, 16.5%, 80.0%, 5.2%, 13.9% and 13.9% , respectively. Except cefoxitin and moxifloxacin, the resistance rates of B. fragilis isolates to the above antibiotics were all higher than those of non-B. fragilis isolates. The positive rates of carbapenem resistance gene cfiA were 38.9% and 8.6% for B. fragilis and non-B. fragilis isolates, respectively. For 15 carbapenem resistant B. fragilis isolates, the co-carrying rates of carbapenem resistance gene cfiA and its upstream IS element were 86.7% (13/15). Conclusions: The overall resistance rates of Bacteroides spp. isolates toward multiple antibiotics were at a higher level, especially for B. fragilis. CfiA gene carrying rate among B. fragilis isolates was high up to 38.9% and its mediated carbapenem resistance was a major resistance mechanism for B. fragilis. The findings of this study imply that the actual resistance tendency of Bacteroides spp. may be underestimated and need to be given more attention to.

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contrasting

confidence: 65%

Higher prevalence of multi-antimicrobial resistant Bacteroides spp. strains isolated at a tertiary teaching hospital, China

Wang¹,

Han²,

Shen³

et al. 2019

Preprint

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“…In this study, the positive rate of the cfiA gene of carbapenem-resistant B. fragilis was as high as 38.9%, which is higher than other recently published reports. 10,18,19 Notably, B. fragilis isolates with a cfiA gene can easily be converted to resistant genes by the effects of its upstream IS element, 20 which implies that a larger group of patients may act as a potential reservoir of carbapenemresistant B. fragilis producers who are colonized or infected by B. fragilis with a silent cfiA gene. Since the B. fragilis isolates tested in this study were mainly from intra-abdominal samples, intestinal screening of cfiA positive B. fragilis within a specific group of people appears to be a beneficial strategy for better understanding the actual distribution of the cfiA gene.…”

Section: Discussionmentioning

confidence: 99%

Higher Prevalence of Multi-Antimicrobial Resistant Bacteroides spp. Strains Isolated at a Tertiary Teaching Hospital in China

Wang

Han

Shen

et al. 2020

IDR

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The study investigates the molecular epidemiology of multi-drug resistant (MDR) Bacteroides spp. isolates and the clinical characteristics of the patients. Materials and Methods: Bacteroides spp. clinical strains were identified through MALDI-TOF MS and VITEK-2 anaerobes and corynebacterium (ANC) cards. A broth microdilution method was employed to detect the antimicrobial sensitivities of Bacteroides spp. isolates. PCR was used to detect the resistance genes, including cfxA, cepA, cfiA, ermF, nim, as well as the upstream insertion sequence (IS) element of the cfiA gene. The effects of broad-spectrum efflux pump inhibitors (EPIs) on the minimal inhibitory concentration (MICs) of cefoxitin, moxifloxacin, and imipenem for MDR Bacteroides spp. were investigated. Results: The total resistance rates of 115 Bacteroides spp. isolates to cefoxitin, moxifloxacin, clindamycin, metronidazole, imipenem and meropenem were 4.3%, 16.5%, 80.0%, 5.2%, 13.9% and 13.9%, respectively. The positive rates of carbapenem resistance gene cfiA were 38.9% and 8.6% for B. fragilis and non-B. fragilis isolates, respectively. The isolation rate of MDR isolates reached up to 18.26% (21/115), and the isolation rate among the gastrointestinal cancer patients was significantly higher when compared to the nongastrointestinal cancer patients (52.38%/26.08%, P = 0.006). Furthermore, MDR isolates were more likely to be isolated from the patients exposed to cephalosporins 3 months before Bacteroides spp. isolation (76.19%/31.52%, P = 0.000). Conclusion:The overall resistance rates of Bacteroides spp. isolates against multiple antimicrobials were at a high level, especially for B. fragilis. The CfiA gene carrying rate among B. fragilis isolates was as high as 38.9%, and its mediated carbapenem resistance was the major resistance mechanism for B. fragilis. The findings of this study imply that the real resistance tendency of Bacteroides spp. may be underestimated and need to be given more attention.

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“…The reference gene, SLCO2A1 , was used for normalization of the cycle threshold (CT) values of each bacterium, as a previous study [ 19 ]. Noteworthy, PCR assay for the detection of B. fragilis enterotoxin gene ( bft ) is carried out as explained by Kouhsari et al [ 20 ]. In this regard, B. fragilis ATCC 43858 and ATCC 25285 strains were used as positive and negative controls, respectively.…”

Section: Methodsmentioning

confidence: 99%

Association between colorectal cancer and Fusobacterium nucleatum and Bacteroides fragilis bacteria in Iranian patients: a preliminary study

Shariati

Razavi

Ghaznavi‐Rad

et al. 2021

Infect Agents Cancer

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Background and aim Recent studies have proposed that commensal bacteria might be involved in the development and progression of gastrointestinal disorders such as colorectal cancer (CRC). Therefore, in this study, the relative abundance of Fusobacterium nucleatum, Bacteroides fragilis, Streptococcus bovis/gallolyticus, and Enteropathogenic Escherichia coli (EPEC) in CRC tissues, and their association with clinicopathologic characteristics of CRC was investigated in Iranian patients. Moreover, the role of these bacteria in the CRC-associated mutations including PIK3CA, KRAS, and BRAF was studied. Method To these ends, the noted bacteria were quantified in paired tumors and normal tissue specimens of 30 CRC patients, by TaqMan quantitative Real-Time Polymerase Chain Reaction (qPCR). Next, possible correlations between clinicopathologic factors and mutations in PIK3CA, KRAS, and BRAF genes were analyzed. Results In studied samples, B. fragilis was the most abundant bacteria that was detected in 66 and 60% of paired tumor and normal samples, respectively. Furthermore, 15% of the B. fragilis-positive patients were infected with Enterotoxigenic B. fragilis (ETBF) in both adenocarcinoma and matched adjacent normal samples. F. nucleatum was also identified in 23% of tumors and 13% of adjacent normal tissue samples. Moreover, the relative abundance of these bacteria determined by 2-ΔCT was significantly higher in CRC samples than in adjacent normal mucosa (p < 0.05). On the other hand, our findings indicated that S. gallolyticus and EPEC, compared to adjacent normal mucosa, were not prevalent in CRC tissues. Finally, our results revealed a correlation between F. nucleatum-positive patients and the KRAS mutation (p = 0.02), while analyses did not show any association between bacteria and mutation in PIK3CA and BRAF genes. Conclusion The present study is the first report on the analysis of different bacteria in CRC tissue samples of Iranian patients. Our findings revealed that F. nucleatum and B. fragilis might be linked to CRC. However, any link between gut microbiome dysbiosis and CRC remains unknown.

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Antimicrobial resistance, prevalence of resistance genes, and molecular characterization in intestinal Bacteroides fragilis group isolates

Cited by 21 publications

References 38 publications

Higher prevalence of multi-antimicrobial resistant Bacteroides spp. strains isolated at a tertiary teaching hospital, China

Higher prevalence of multi-antimicrobial resistant Bacteroides spp. strains isolated at a tertiary teaching hospital, China

<p>Higher Prevalence of Multi-Antimicrobial Resistant <em>Bacteroides</em> spp. Strains Isolated at a Tertiary Teaching Hospital in China</p>

Association between colorectal cancer and Fusobacterium nucleatum and Bacteroides fragilis bacteria in Iranian patients: a preliminary study

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