Comparison of teicoplanin disk diffusion and broth microdilution methods against clinical isolates of Staphylococcus aureus and S. epidermidis

Camargo, Carlos Henrique; Mondelli, Alessandro Lia; Bôas, Paulo José Fortes Villas

doi:10.1590/s1517-83822011000400003

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…Results for vancomycin by disk diffusion test have been criticized and in 2011 the CLSI M100-S19 document has recommended the disuse of vancomycin disks for staphylococci and informed that studies on the action of teicoplanin in disk-diffusion testing should be performed (Camargo et al . 2011 ), however, for screening purposes, such as in this study, the disk diffusion test is still a viable choice, especially for enterococci (Hegstad et al . 2014 ; Wongthong et al .…”

Section: Resultsmentioning

confidence: 97%

Evolution and antimicrobial resistance of enterococci isolated from Pecorino and goat cheese manufactured on-farm in an area facing constraints as per EU Regulation 1305/2013 in Umbria, Italy

et al. 2022

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The latest EU regulation on geographical indications (EU Regulation No. 1151/2012) has introduced a set of new tools for the protection and enhancement of food products in rural areas, under the group name of optional quality term (OQT). The Commission Delegated EU Regulation, No. 665/2014, regulated the conditions for the use of the optional quality term mountain product (MP), to support the implementation of a mountain value chain. This new tool is aimed at promoting local development, maintaining the economic activities in mountain areas, and redistributing wealth, whilst, at the same time, promoting the territory. Pecorino and goat cheeses are typical Italian cheeses made usually with whole raw ewe’s or raw goat’s milk, without starter culture addition. In an attempt to characterize these productions, the aim of this study was to investigate the evolution of enterococci during the production and ripening of Pecorino cheese made in three different farms, located in Umbria, Italy in areas facing natural or other specific constraints as stipulated by Regulation 1305/2013 on support for rural development by the European Agricultural Fund for Rural Development (EAFRD). Enterococci are enteric organisms which are commonly isolated from ewe and goat’s milk production in Umbria, Italy. Counts of enterococci in raw milk ranged from 1.75 for ovine milk to 3.62 for ewe milk and a marked reduction was observed after thermization especially in ovine milk. Out of 100 isolates, 69 were E. faecium, 23 E. durans, 8 E. faecalis and 2 E. casseliflavus and the distribution of species between farms and between samples showed a prevalence of E. faecium in ovine farms and E. durans in ewes farms, with an equal dis-tribution between samples. High percentages of susceptible isolates were found for amoxicillin/clavulanic acid, ampicillin, chloramphenicol, sulphamethoxazole, sulphamethoxazole/ trimethoprim, ticarcillin, vancomycin. A high prevalence of resistant strains (>30%) was ob-served for amikacin, ciprofloxacin, ceftriaxone, kanamycin, tetracycline. A comparison of this results with those of previous works on similar dairy products revealed high levels of resistance to antimicrobials which needs to be addressed.

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Section: Resultsmentioning

confidence: 97%

Evolution and antimicrobial resistance of enterococci isolated from Pecorino and goat cheese manufactured on-farm in an area facing constraints as per EU Regulation 1305/2013 in Umbria, Italy

et al. 2022

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“…Teicoplanin resistance is an increasing and emerging challenge, but published data are inconclusive due to a number of factors. These include the different methods employed (e.g., broth microdilution vs. disk diffusion [ 4 ]); settings, diagnostic vs. research (e.g., broth microdilution vs. population analysis); the standards employed (e.g., CLSI vs. EUCAST defined breakpoints); the inclusion of diverse cohorts (e.g., catheter-related bacteremia vs. healthy volunteers [ 17 , 19 ]; the bacterial species studied (most studies have focused on S. aureus and fewer on CoNS [ 20 ]); clonal dissemination [ 21 ]; data generated at different time points [ 22 ]; or that teicoplanin was not tested. Thus, to date, reports have probably underestimated the true incidence of teicoplanin resistance and are still insufficient to identify its underlying mechanisms with certainty.…”

Section: Discussionmentioning

confidence: 99%

Teicoplanin-Resistant Coagulase-Negative Staphylococci: Do the Current Susceptibility Testing Methods Reliably Detect This Elusive Phenotype?

Balasiu

MacKenzie

2023

Antibiotics

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Coagulase-negative staphylococci (CoNS), members of the skin commensal microbiota, are increasingly associated with local or systemic infections due to a shift in patient populations in recent decades. Subsequently, more CoNS strains have been subjected to antibiotic susceptibility testing (AST), thus leading to the increased detection of teicoplanin resistance. However, data concerning teicoplanin resistance among CoNS strains remain limited, heterogeneous, and inconclusive. We collected 162 consecutive CoNS strains identified using Vitek-2 as teicoplanin-resistant and tested them with a range of AST methods. The results of standard and high inoculum broth microdilution (sBMD; hBMD), agar dilution (AD) after 24 h and 48 h incubation, standard and macrogradient diffusion strip (sGDT, MET), screening agar, and disc diffusion were compared to assess their robustness and to establish a diagnostic algorithm to detect teicoplanin resistance. sBMD was used as the reference method, and the lowest number of strains were teicoplanin-resistant using this method. sGDT and disc diffusion generated similar results to sBMD. Compared with sBMD, AD-24 h generated the lowest number of false teicoplanin-resistant strains, followed by hBMD, AD-48 h, and Vitek-2. sGDT, a fast, easy, affordable method in diagnostic settings, generated the highest rate of false teicoplanin-susceptible strains. Vitek-2 testing produced the highest number of teicoplanin-resistant strains. Only in two strains was the initial Vitek-2 teicoplanin resistance confirmed using five other AST methods. In conclusion, the different antibiotic susceptibility testing methods generated inconsistent, inconclusive, and discrepant results, thus making it difficult to establish a diagnostic algorithm for suspected teicoplanin resistance. Teicoplanin testing proved to be challenging and easily influenced by technical factors. This study aimed not only to raise awareness of teicoplanin resistance testing but also of the need for future studies focusing on the clinical efficacy of teicoplanin in relation to its susceptibility results.

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“…(1) 'nın çalışmasında 63 stafilokok suşunun bu iki yöntem ile elde edilen duyarlılık sonuçla-rının % 96.8 oranında uyumlu bulunduğu bildirilmiş, uyumsuz sonuç bulunan tüm stafilokokların (iki suş) S.epidermidis olduğu ve uyumsuzluğun minör hata düzeyinde olduğunu (DD ile orta duyarlı iken mikrodilüsyon ile duyarlı ya da dirençli olması) belirtilmiştir. Araştırmacılar bu bulgularına dayanarak DD yönteminin en azından kendi hastaneleri için halen stafilokokların teikoplanin duyarlılığını tespit etmede kullanılabileceğini öne sürmüştür.…”

Section: Discussionunclassified

Do the Method and / or the Evaluation Standards We Use Affect Teicoplanin Susceptibility Test Results of Staphylococcus Strains?

Çetin¹,

Öztürk²,

Çiftçi³

et al. 2016

Ankem Derg

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ÖZET Stafilokok suşlarının teikoplanin duyarlılığının belirlenmesi için Clinical Laboratory Standards Institute (CLSI) M100-S23 rehberinde disk difüzyon (DD) değerlendirme kriterleri verilmiş olsa da bu yöntemin teikoplanine orta duyarlı ya da dirençli suşları duyarlılardan ayırmadaki etkinliğinin açık olmadığı bildirilmektedir. Diğer taraftan, European Committee on Antimicrobial Susceptibility Testing (EUCAST) ise stafilokokların teikoplanin duyarlılığının değerlen DD veya GST ile orta duyarlı bulunmuş iken referans yöntem ile dirençli veya duyarlı bulunmuş veya tersi ise küçük hata olarak kategorize edilmiştir. S.aureus suşları CLSI rehberine göre değerlendirildiğinde DD ve GST, SMD ile % 100 uyumlu, EUCAST kriterleri dikkate alınarak değerlendirildiğin-de ise GST, SMD metodu ile % 92 oranında uyumlu sonuç vermiştir (% 5 çok büyük hata, % 3 büyük hata). CLSI kriterlerine göre KNS'lerin 17'si teikoplanine orta derecede duyarlı bulunurken GST ve DD yöntemleri SMD ile % 85 uyumlu sonuç vermiştir (% 15 küçük hata). KNS'lerin duyarlılık test sonuçları EUCAST kriterleri dikkate alınarak değerlendirildiğinde ise yöntemler arası uyumun % 71 olduğu görülmüştür (% 29 çok büyük hata). Sonuç olarak, referans yöntemle teikoplanine duyarlı bulunan suşlar için yöntemler arasında uyum problemi görülmezken orta derecede duyarlı ve dirençli bulunan suşlar için DD ve GST'nin Although disk diffusion (DD) interpretive criteria for the evaluation of teicoplanin susceptibility are given in the Clinical Laboratory Standards Institute (CLSI) M100-S23 document, it has been mentioned that the ability of DD method to differentiate teicoplanin-intermediate and teicoplanin-resistant staphylococci from teicoplanin-susceptible strains is not clear. On the other hand, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reports that DD method is unreliable for teicoplanin susceptibility testing. We aimed in this study to determine the compliance of DD and Gradient Strip Test (GST) methods with broth microdilution (BMD) method in respect of

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Comparison of teicoplanin disk diffusion and broth microdilution methods against clinical isolates of Staphylococcus aureus and S. epidermidis

Cited by 5 publications

References 9 publications

Evolution and antimicrobial resistance of enterococci isolated from Pecorino and goat cheese manufactured on-farm in an area facing constraints as per EU Regulation 1305/2013 in Umbria, Italy

Evolution and antimicrobial resistance of enterococci isolated from Pecorino and goat cheese manufactured on-farm in an area facing constraints as per EU Regulation 1305/2013 in Umbria, Italy

Teicoplanin-Resistant Coagulase-Negative Staphylococci: Do the Current Susceptibility Testing Methods Reliably Detect This Elusive Phenotype?

Do the Method and / or the Evaluation Standards We Use Affect Teicoplanin Susceptibility Test Results of Staphylococcus Strains?

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