Comparative Study of Three β Lactamase Test Methods in &amp;lt;i&amp;gt;Staphylococcus&amp;lt;/i&amp;gt; aureus Isolated from Two Nepalese Hospitals

Shrestha, Bikal; Suman, Rana Shamser

doi:10.4236/ojcd.2014.41009

Cited by 17 publications

(12 citation statements)

References 13 publications

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“…The result of the nitrocefin test, which is considered a highly sensitive method for detection of the bacterial β-lactamase enzyme [ 19 ], was negative for all ampicillin-resistant Lactobacillus isolates tested.…”

Section: Resultsmentioning

confidence: 99%

Assessment of antibiotic susceptibility in Lactobacillus isolates from chickens

et al. 2017

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BackgroundThe aim of this study was to determine the susceptibility of 88 Lactobacillus isolates derived from chickens to antibiotic substances and to detect drug-resistance genes.ResultsThe minimal inhibitory concentration of 13 antimicrobial substances was determined by the broth microdilution method, and resistance genes were detected by PCR. We recorded a high prevalence of resistance to tiamulin (90% resistant isolates), tetracyclines (74%) and lincomycin (70%), and a moderately high frequency of resistance to enrofloxacin (48%), macrolides (42%), aminoglycosides (12.5–31%), ampicillin (26%) and chloramphenicol (23%). Multi-drug resistance was observed in 79.5% of isolates. The presence of resistance genes was generally correlated with phenotypic resistance, but some molecular determinants were also recorded in susceptible isolates. Among tetracycline resistance genes, the most frequently identified was tetW (45% isolates), followed by tetM (26%) and tetL (24%). The ermB, ermC and lnuA genes, associated with resistance to macrolides and lincosamides, were observed in 39, 12 and 39% of isolates, respectively. Among genes determining resistance to aminoglycoside antibiotics, we identified ant(6)-Ia (10% of isolates), aac(6′)-Ie-aph(2′)-Ia (8%), aph(2″)-Ic (6%) and aadE (4.5%). The cat gene was present in 32 isolates, including 8 of 20 found to be resistant to chloramphenicol. Two genes encoding efflux pumps were identified—the acrA gene was present in all isolates tested, and 10 of 79 lactobacilli determined to be phenotypically resistant to tiamulin contained the lsaE gene. We were unable to explain the resistance mechanism of Lactobacillus isolates to ampicillin, but showed that it did not involve the production of β-lactamases.ConclusionsOur findings indicate that intestinal lactobacilli should be considered a reservoir of resistance genes and that antibiotics must be used prudently in poultry production. The data derived from this study can be used as a basis for reviewing current microbiological breakpoints for categorization of susceptible and resistant strains within the genus Lactobacillus.

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Section: Resultsmentioning

confidence: 99%

Assessment of antibiotic susceptibility in Lactobacillus isolates from chickens

et al. 2017

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“…The skyrocketing production of β-lactamase by the studied strain must be due the presence of plasmid mediated resistant genes (15) . As it is previously reported by Bidya S et al that β-lactamase genes are encode by plasmid DNA (8) . Plasmid DNA of the selected strain was very heavy in size, Pryce LH et al consensus that the Vibrio spp usually carries large plasmid DNA (17) .…”

Section: Discussionmentioning

confidence: 54%

“…Bacterial cell wall restraining antibiotics are widely used by clinicians. β-lactams are the most commonly used family of antibiotics known for the mentioned target site, though resistance against these drugs becoming the global issue, the reason behind this drastic situation is the production and secretion of β-lactamases which is capable to degrade β-lactam ring (8) . A very well-known β-lactam antibiotic Ampicillin with broad spectrum action and fairly non-toxic effect is greatly resisted by several pathogens.…”

Section: Introductionmentioning

confidence: 99%

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2017

IAM

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Objective: β-lactamase enzyme is encoded by the plasmid mediated genes which is very effective against β-lactam antibiotics. This enzyme is produced by many gram negative bacteria which consequences hinder in in therapy with many efficient β-lactam antibiotics. The aim of this study is to assess the susceptibility of the strain, isolated from marine water against Ampicillin (antibiotics) and the production of β-lactamase. Material and Methods: Marine water samples were collected from Clifton Beach during summer in sterile condition; organisms were identified and characterized through biochemical analysis. MIC for ampicillin was determined by broth dilution method. Plasmid extraction was performed by following the modified method of Birnboim Doly. β-lactamase was also detected by iodometric cell suspension method. Results: Ampicillin resistance was observed in selected strain. Isolated gram negative bacilli strain was highly resistant to ampicillin (≥ 2500µg/ml). Through the analysis of colonial morphology, microscopic examination and plasmid extraction (which was found as 10 kb in size) strain was suspected as Vibrio spp. The results of iodometric assay for β-lactamase was also considerable. Conclusion: The dreadful spread of antibiotic resistant mechanism in aquatic environment and the excessive use of antibiotic were highlighted. Marine isolates were characterized and identified as luminescent bacteria. A simple and convenient method of β-lactamase analysis through iodometric assay has been applied which was found to be a reliable technique as compare to other β-lactamase quantification method.

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“…The plates were incubated at 35°C in 5% CO 2 for 22 hours, and MIC values of the test drugs against clinical H. influenzae isolates were measured. Furthermore, the β-lactamase producing ability was determined by the nitrocefin method (12). Based on these results, percentages of BLNAR and β-lactamase-producing bacteria over time are shown in Figure 1.…”

Section: Resultsmentioning

confidence: 99%

“…Each bacterial strain was cultured on chocolate agar medium (Nippon Beckton-Dickinson, Tokyo, Japan) at 35°C in 5% CO 2 for 22 hours (8), and then nitrocefin (Kantokagaku, Tokyo, Japan) was added in drops to H. influenzae ; the strain was considered to be capable of producing β-lactamase when the red color developed (12).…”

Section: Methodsmentioning

confidence: 99%

Monitoring quinolone resistance due to Haemophilus influenzae mutations (2012–17)

Nagatomo

Shirakura

Fukuchi

et al. 2019

Preprint

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17Among drug-resistant bacteria of recent concern, we determined minimum inhibitory 18 concentrations (MICs) of six different quinolone antibacterial agents in Haemophilus 19 influenzae and performed molecular genetic analysis in addition to the exploration for 20 β-lactamase-producing and β-lactamase negative ampicillin-resistant H. influenzae 21 (BLNAR). A total of 144 clinical H. influenzae strains isolated at the Showa University 22 Hospital between 2012 and 2017 were subjected to MIC determination for 23 penicillin/quinolone antibacterial agents using the nitrocefin method and the Clinical 24 and Laboratory Standards Institute broth microdilution method. Moreover, amino acid 25 mutations in the quinolone resistance-determining regions (QRDRs) were analyzed in 26 the isolates showing MIC value of ≥ 0.25 µg/ml of quinolone antibacterial agents. 27Increasing proportions of BLNAR were noted, with 15% in 2015 to 43.5% in 2016 and 28 63.6% in 2017. Among quinolone antibacterial agents, all isolates remained susceptible 29 to sitafloxacin (STFX), and STFX showed strong inhibitory potencies against both 30 DNA gyrase and topoisomerase IV. For moxifloxacin (MXF), however, strains with 31 MIC value of 0.5 µg/ml were detected every year since 2013 except 2015. Amino acid 32 mutations were investigated in 17 isolates (11.8%) with MXF MIC value of ≥0.25 33 µg/ml, and confirmed in 11 isolates (7.6%), of which mutations of GyrA were found in 34 3 3 9 isolates. Future antibacterial drug regimens may need to address the emergence of 35 quinolone-resistant H. influenzae. 36 37 38 4 4 Introduction 39 Haemophilus influenzae is the second most common causative bacterium of 40 community-acquired pneumonia, following Streptococcus pneumoniae, and has taken 41 the leading position after pneumococcal vaccines became popular (1). β-Lactam 42 antibiotics have previously been used for the treatment of community-acquired 43 pneumonia. In the 2000s, however, β-lactamase producing ampicillin-resistant (BLPAR) 44 bacteria have been increasingly detected in Canada (2), Japan, and some other countries. 45 In addition, β-lactamase negative ampicillin-resistant (BLNAR) bacteria have been 46 increasingly detected in Japan in the recent years (3). Moreover, BLNAR bacteria 47 65 GyrA gene encoding DNA gyrase or ParC gene encoding topoisomerase IV, which 66 cause three-dimensional structural alterations in the respective enzymes and decrease 67 the affinity between fluoroquinolones and these replication enzymes (9). In the case of 68 H. influenzae, drug resistance has been shown to be strongly related to mutations of 69 serine and aspartic acid at positions 84 and 88 of GyrA and of serine at position 84 of 70 ParC (10). However, only a limited number of previous studies have investigated 71 mutations in QRDRs in the same institution over time or have compared MICs among 72 different quinolones.In this study, we tested sensitivity levels to quinolone and 73 penicillin antibacterial agents over 6 years in H. influenzae strains that were isolated at ...

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Comparative Study of Three β Lactamase Test Methods in <i>Staphylococcus</i> aureus Isolated from Two Nepalese Hospitals

Cited by 17 publications

References 13 publications

Assessment of antibiotic susceptibility in Lactobacillus isolates from chickens

Assessment of antibiotic susceptibility in Lactobacillus isolates from chickens

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Monitoring quinolone resistance due to Haemophilus influenzae mutations (2012–17)

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