Growing Menace of Antibacterial Resistance in Clinical Isolates ofPseudomonas aeruginosain Nepal: An Insight of Beta-Lactamase Production

Introduction. Pseudomonas aeruginosais the most frequently isolated organism as it acts as the opportunistic pathogen and can cause infections in immunosuppressed patients. The production of different types of beta-lactamases renders this organism resistant to many commonly used antimicrobials. Therefore, the aim of this study was to document the antibiotic resistance rate inPseudomonas aeruginosaisolated from different clinical specimens.Methods. Pseudomonas aeruginosarecovered was identified by standard microbiological methods. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disc diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines and all the suspected isolates were tested for the production of ESBLs, MBLs, and AmpC.Results.Out of total (178) isolates, 83.1% were recovered from the inpatient department (IPD). Majority of the isolates mediated resistance towards the beta-lactam antibiotics, while nearly half of the isolates were resistant to ciprofloxacin. Most of the aminoglycosides used showed resistance rate up to 75% but amikacin proved to be better option. No resistance to polymyxin was observed. ESBLs, MBLs, and AmpC mediated resistance was seen in 33.1%, 30.9%, and 15.7% isolates, respectively.Conclusions. Antibiotic resistance rate and beta-lactamase mediated resistance were high. Thus, regular surveillance of drug resistance is of utmost importance.

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Presence of different beta-lactamase classes among clinical isolates of Pseudomonas aeruginosa expressing AmpC beta-lactamase enzyme

The Journal of Infection in Developing Countries ◽

10.3855/jidc.497 ◽

2010 ◽

Vol 4 (04) ◽

pp. 239-242 ◽

Cited By ~ 16

Author(s):

Supriya Upadhyay ◽

Malay Ranjan Sen ◽

Amitabha Bhattacharjee

Keyword(s):

Pseudomonas Aeruginosa ◽

Treatment Options ◽

Clinical Isolates ◽

Diffusion Method ◽

Beta Lactamase ◽

Beta Lactam ◽

Disk Diffusion Method ◽

Extended Spectrum Beta Lactamase ◽

Extended Spectrum ◽

Enzyme Detection

Introduction: Infections caused by Pseudomonas aeruginosa are difficult to treat as the majority of isolates exhibit varying degrees of beta-lactamase mediated resistance to most of the beta-lactam antibiotics. It is also not unusual to find a single isolate that expresses multiple β-lactamase enzymes, further complicating the treatment options. Thus the present study was designed to investigate the coexistence of different beta-lactamase enzymes in clinical isolates of P. aeruginosa. Methodology: A total of 202 clinical isolates of P. aeruginosa were tested for the presence of AmpC beta-lactamase, extended spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) enzyme. Detection of AmpC beta-lactamase was performed by disk antagonism test and a modified three-dimensional method, whereas detection of ESBL was done by the combined disk diffusion method per Clinical and Laboratory Standards Institute (CLSI) guidelines and MBL were detected by the Imipenem EDTA disk potentiation test. Results: A total of 120 (59.4%) isolates were confirmed to be positive for AmpC beta-lactamase. Among them, 14 strains (7%) were inducible AmpC producers. Co-production of AmpC along with extended spectrum beta-lactamase and metallo beta-lactamase was reported in 3.3% and 46.6% isolates respectively. Conclusion: The study emphasizes the high prevalence of multidrug resistant P. aeruginosa producing beta-lactamase enzymes of diverse mechanisms. Thus proper antibiotic policy and measures to restrict the indiscriminative use of cephalosporins and carbapenems should be taken to minimize the emergence of this multiple beta-lactamase producing pathogens.

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A TEM-derived extended-spectrum beta-lactamase in Pseudomonas aeruginosa.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.11.2488 ◽

1996 ◽

Vol 40 (11) ◽

pp. 2488-2493 ◽

Cited By ~ 47

Author(s):

P Mugnier ◽

P Dubrous ◽

I Casin ◽

G Arlet ◽

E Collatz

Keyword(s):

Pseudomonas Aeruginosa ◽

Clinical Strain ◽

Beta Lactamase ◽

Beta Lactam ◽

Aminoglycoside Resistance ◽

Double Mutation ◽

Extended Spectrum Beta Lactamase ◽

Beta Lactam Antibiotics ◽

Extended Spectrum ◽

High Level

A clinical strain of Pseudomonas aeruginosa, PAe1100, was found to be resistant to all antipseudomonal beta-lactam antibiotics and to aminoglycosides, including gentamicin, amikacin, and isepamicin. PAe1100 produced two beta-lactamases, TEM-2 (pI 5.6) and a novel, TEM-derived extended-spectrum beta-lactamase called TEM-42 (pI 5.8), susceptible to inhibition by clavulanate, sulbactam, and tazobactam. Both enzymes, as well as the aminoglycoside resistance which resulted from AAC(3)-IIa and AAC(6')-I production, were encoded by an 18-kb nonconjugative plasmid, pLRM1, that could be transferred to Escherichia coli by transformation. The gene coding for TEM-42 had four mutations that led to as many amino acid substitutions with respect to TEM-2: Val for Ala at position 42 (Ala42), Ser for Gly238, Lys for Glu240, and Met for Thr265 (Ambler numbering). The double mutation Ser for Gly238 and Lys for Glu240, which has so far only been described in SHV-type but not TEM-type enzymes, conferred concomitant high-level resistance to cefotaxime and ceftazidime. The novel, TEM-derived extended-spectrum beta-lactamase appears to be the first of its class to be described in P. aeruginosa.

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ESBL Producers in Gram Negative Isolates from Clinical Samples

Journal of Pure and Applied Microbiology ◽

10.22207/jpam.14.3.42 ◽

2020 ◽

Vol 14 (3) ◽

pp. 2027-2032

Author(s):

Mita D. Wadekar ◽

J.V. Sathish ◽

C. Pooja ◽

S. Jayashree

Keyword(s):

Treatment Options ◽

Multidrug Resistant ◽

Diffusion Method ◽

Clinical Samples ◽

Beta Lactamase ◽

Beta Lactam ◽

Gram Negative ◽

Extended Spectrum Beta Lactamase ◽

Beta Lactam Antibiotics ◽

Esbl Producers

Resistance to beta lactam antibiotics is the most common cause for beta-lactamase production. Increasing number of extended spectrum beta-lactamase (ESBL) producers has reduced the treatment options which resulted in emergence of multidrug resistant strains, treatment failure and hence increased mortality. To detect phenotypically, ESBL producers in Gram negative isolates from different samples and to know their susceptibility pattern. A retrospective study of Gram negative isolates was conducted. Total of 521 isolates were isolated from various samples. They were processed and identified by standard procedures. The antibiotic susceptibility testing was performed by Kirby- Bauer disc diffusion method using CLSI guidelines. ESBL was detected by combination disk test. A total of 521 Gram negative isolates were isolated which included E. coli, Klebsiella pneumoniae, Citrobacter spp., Enterobacter spp., Proteus spp. and Acinetobacter spp. Pseudomonas aeruginosa. Of 521 isolates tested, ESBL was detected in 329 (63.1%) isolates. These isolates showed maximum susceptibility to piperacillin- tazobactam (86%) followed by imipenem (78.4%), amikacin (63.5%), cotrimoxazole (54.4%), ciprofloxacin (51%), amoxi-clav (44.9%), cefepime (44.1%), gentamicin (38.9%), cefoxitin (34.9%) and ampicillin (19.1%). ESBL producers which are resistant to beta lactam antibiotics have become a major problem. Detection of these beta-lactamase enzymes by simple disk method and its reporting will help clinicians in prescribing proper antibiotics.

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Evaluation of the presence of AmpC (FOX) beta-lactamase gene in clinical strains of Escherichia coli isolated from hospitalized patients in Tabriz, Iran

Journal of Experimental and Clinical Medicine ◽

10.52142/omujecm.38.3.17 ◽

2021 ◽

Vol 38 (3) ◽

pp. 301-304

Author(s):

Zahra SADEGHI DEYLAMDEH ◽

Abolfazl JAFARI SALES

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Hospitalized Patients ◽

Disk Diffusion ◽

Beta Lactamase ◽

Beta Lactam ◽

Beta Lactamases ◽

Clinical Strains ◽

Beta Lactam Antibiotics ◽

Lactamase Gene

Beta-lactamases are the most common cause of bacterial resistance to beta-lactam antibiotics. AmpC-type beta-lactamases hydrolyze cephalosporins, penicillins, and cephamycins. Therefore, the study aims was to determine antibiotic resistance and to investigate the presence of AmpC beta-lactamase gene in clinical strains of Escherichia coli isolated from hospitalized patients in Tabriz. In this cross-sectional descriptive study, 289 E. coli specimens were collected from clinical specimens. Disk diffusion method and combined disk method were used to determine the phenotype of extended spectrum β-Lactamase producing (ESBLs) strains. Then PCR was used to evaluate the presence of AmpC (FOX) beta-lactamase gene in the strains confirmed in phenotypic tests. Antibiotic resistance was also determined using disk diffusion by the Kibry-Bauer method. A total of 121 isolates were identified as generators of beta-lactamase genes. 72 (59.5 %) isolates producing ESBL and 49 (40.5 %) isolates were identified as AmpC generators. In the PCR test, 31 isolates contained the FOX gene. The highest resistance was related to the antibiotics amoxicillin (76.12%), ceftazidime (70.24%) and nalidixic acid (65.05%). The results indicate an increase in the prevalence of beta-lactamase genes and increased resistance to beta-lactam antibiotics, which can be the result of improper use of antibiotics and not using antibiotic susceptibility tests before starting treatment. Also, using phenotypic and molecular diagnostic methods such as PCR together can be very useful.

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First Global Report of Plasmid-Mediated mcr-1 and Extended-Spectrum Beta-Lactamase-Producing Escherichia coli from Sheep in Portugal

Antibiotics ◽

10.3390/antibiotics10111403 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1403

Author(s):

Josman Dantas Palmeira ◽

Marisa Haenni ◽

Jean-Yves Madec ◽

Helena Maria Neto Ferreira

Keyword(s):

One Health ◽

Diffusion Method ◽

Beta Lactamase ◽

Beta Lactam ◽

Colistin Resistance ◽

Disk Diffusion Method ◽

Extended Spectrum Beta Lactamase ◽

E Coli ◽

Beta Lactam Antibiotics ◽

Extended Spectrum

Resistances to extended-spectrum cephalosporins (ESC) and colistin are One Health issues since genes encoding these resistances can be transmitted between all sectors of the One Health concept, i.e., human, animal, and the environment. Among food-producing animals, sheep farming has long been overlooked. To fill in this knowledge gap, we looked for ESC- and colistin resistance in 21 faecal samples collected from sheep in one farm in the south of Portugal. ESC-resistant isolates were selected on MacConkey agar plates supplemented with cefotaxime. Susceptibility testing was performed by the disk-diffusion method according to CLSI, while colistin MIC was determined by broth microdilution. ESC- and colistin-resistance genes were identified by PCR, and the clonality of all isolates was assessed by XbaI-PFGE. The replicon content was determined by PCR according to the PCR-based replicon typing (PBRT) scheme. Sixty-two non-duplicate ESC-resistant E. coli isolates were identified, which all presented an extended-spectrum beta-lactamase (ESBL) phenotype, mostly due to the presence of CTX-M genes. One CTX-M-1-producing E. coli was concomitantly colistin-resistant and presented the plasmid-mediated mcr-1 gene. Nearly all isolates showed associated resistances to non-beta-lactam antibiotics, which could act as co-selectors, even in the absence of beta-lactam use. The results showed a high proportion of ESBL-producing E. coli in sheep faeces. Their dissemination was very dynamic, with the spread of successful clones between animals, but also a large diversity of clones and plasmids, sometimes residing in the same animal. This study highlights the need for global surveillance in all food-producing sectors, in order to avoid the dissemination of genes conferring resistance to last-resort antibiotics in human medicine.

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Comparative antibiotic resistance of S. aureus strains isolated in surgical and therapeutic departments of hospitals

Science and Innovations in Medicine ◽

10.35693/2500-1388-2020-5-2-83-87 ◽

2020 ◽

Vol 5 (2) ◽

pp. 83-87

Author(s):

Ivan V. Zhyltsou

Keyword(s):

Antibiotic Resistance ◽

Test System ◽

Clinical Isolates ◽

Diffusion Method ◽

Bacterial Suspension ◽

Beta Lactamase ◽

Beta Lactam ◽

Staphylococcal Infections ◽

Antistaphylococcal Activity ◽

Duration Of Hospitalization

Objectives - to identify the characteristics of resistance of clinical isolates of S. aureus, obtained in hospitals of various specialization, to beta-lactam antibiotics, and to improve recommendations for empirical etiotropic therapy prescribed to patients with staphylococcal infections. Materials and methods. The subject of the study is the clinical isolates of S. aureus received from patients hospitalized to Vitebsk Regional Clinical Infectious Diseases Hospital "therapeutic" isolates, n=117) and purulent surgery departments and intensive care units of Vitebsk Regional Clinical Hospital ("surgical" isolates, n=111) in 2016-2017 years. Methods for the study of antibiotic resistance of clinical isolates of S. aureus: disk diffusion method, method for determining the beta-lactamase activity of bacterial suspension using the "BioLactam" test system. Results. It was found, that 80.6% of the therapeutic isolates and 73.2% of the surgical isolates were resistant to the 1st generation penicillins. 5.4% of therapeutic isolates and 34% of surgical isolates were resistant to inhibitor-protected beta-lactams. 36.8% of surgical isolates and no therapeutic isolates were resistant to cephalosporins of the 3rd generation. No MRSA were detected among the therapeutic isolates, and among the surgical isolates the prevalence of MRSA was 30.5%. 93.3% of therapeutic isolates of S. aureus did not show any beta-lactamase activity. Among surgical isolates there were only 34.4% of such isolates. Direct Spearman's correlations of moderate strength were revealed between the levels of beta-lactamase activity of S. aureus isolates, the duration of hospitalization and febrile period, as well as between the isolation of MRSA and the duration of hospitalization, fever and diarrheal syndrome. Conclusion. The use of inhibitor-protected penicillins and 3rd generation cephalosporins is recommended for empirical antibiotic therapy of "therapeutic" infections caused by S. aureus. Reserve antibiotics with selective antistaphylococcal activity (such as glycopeptides or oxazolidinones) are required for empirical antibacterial therapy of staphylococcal infections in surgical departments and resuscitation units

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Detection of Virulence Factors and Antibiotic Resistance Pattern of Clinical and Intensive Care Unit Environmental Isolates of Pseudomonas aeruginosa

Infectious Disorders - Drug Targets ◽

10.2174/1871526520666191231124717 ◽

2020 ◽

Vol 20 (5) ◽

pp. 758-762

Author(s):

Omid Zarei ◽

Hassan Mahmoudi ◽

Ali Mohammadi Bardbari ◽

Pezhman Karami ◽

Mohammad Yousef Alikhani

Keyword(s):

Intensive Care Unit ◽

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Intensive Care ◽

Virulence Factors ◽

Opportunistic Pathogen ◽

Diffusion Method ◽

Resistance Pattern ◽

Disk Diffusion Method ◽

Human Infections

Background: Pseudomonas aeruginosa is a gram-negative non-glucose fermenting aerobic bacteria and an opportunistic pathogen in humans and animals. The present study was carried out to investigate the distribution of virulence factors and antibiotic resistance properties of P. aeruginosa isolated from patients and intensive care unit (ICU) environment. Material and Methods: A total of 116 P. aeruginosa isolated from patients and ICU environment were collected from Besat hospital in Hamadan, the West of Iran. P. aeruginosa isolates were analyzed based on the presence of the virulence factors encoding genes included exoA, exoS, exoU, and algD using polymerase chain reaction (PCR). Antimicrobial susceptibility test was performed using a disk diffusion method. Results: The results showed the prevalence of exoA 33 (56.9%), exoS 21 (36.20%), exoU 37 (63.8%), and algD 35 (60.34%) genes in ICU environment P. aeruginosa strains and exo A 23 (39.25%), exoS 25 (43.1%), exoU 40(68.98%), and algD 25 (43.1%) genes in clinical isolates of P. aeruginosa. High resistance levels of the clinical and ICU environment isolate to ampicillinsulbactam (100%), were also observed. Conclusions: Our findings should raise awareness about antibiotic resistance in hospitalized patients in Iran. Clinicians should exercise caution in prescribing antibiotics, especially in cases of human infections.

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Comprehensive analysis of imipenemase (IMP)-type metallo-Beta-lactamase showing global distribution threating Asia

10.20944/preprints202201.0156.v1 ◽

2022 ◽

Author(s):

Pisut Pongchaikul ◽

Paninee Mongkolsuk

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Antimicrobial Resistance ◽

Comprehensive Analysis ◽

Regional Level ◽

Global Distribution ◽

Beta Lactamase ◽

Global Level ◽

Beta Lactam ◽

Susceptibility Profiles

Antibiotic resistance, particularly beta-lactam resistance, is a major problem worldwide. Imipenemase or IMP-type metallo-beta-lactamase (MBL) has become a more prominent enzyme, especially in Asia, since it was discovered in the 1990s in Japan. There are currently more than 91 variants of IMP-type enzymes. The most commonly identified variant of IMP-type enzymes is IMP-1 variant. IMP-type MBLs have been identified in more than 10 species in Enterobacterales. Pseudomonas aeruginosa is the most frequent carrier of IMP-type enzymes worldwide. In Asia, IMP-type MBLs have been distributed in many countries in the region. This work investigated a variety of currently available IMP-type MBLs in both global level and regional level. Out of 88 variants of IMP-type MBLs reported worldwide, only 32 variants were found to have susceptibility profiles. Most of the IMP-type MBLs were resistant to Carbapenems, especially Imipenem and Meropenem, followed by the 3rd generation cephalosporins, and interestingly, monobactams. Our results comprehensively indicated the distribution of IMP-type MBLs in Asia and raised the awareness of the situation of antimicrobial resistance in the region.

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Redox protein OsaR (PA0056) regulates dsbM and the oxidative stress response in Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01771-20 ◽

2020 ◽

Author(s):

Yujie Liu ◽

Yibing Ma ◽

Zhongqiang Ma ◽

Xiao Han ◽

Hang Qi ◽

...

Keyword(s):

Oxidative Stress ◽

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Stress Response ◽

Gene Cluster ◽

Oxidative Stress Response ◽

Antibiotics Resistance ◽

Transcriptional Level ◽

Beta Lactam ◽

Beta Lactam Antibiotics

Bacteria have evolved distinct molecular mechanisms as a defense against oxidative stress. The foremost regulator of oxidative stress response has been found to be OxyR. However, the molecular details of regulation upstream of OxyR remain largely unknown and need further investigation. Here, we characterize a oxidant stress and antibiotic tolerance regulator, OsaR (PA0056), produced by Pseudomonas aeruginosa. Mutation of osaR increased bacterial tolerance to aminoglycoside and beta-lactam antibiotics, as well as to hydrogen peroxide. Expression of the oxyR regulon genes oxyR, katAB, and ahpBCF was increased in the osaR mutant. However, the OsaR protein does not regulate the oxyR regulon genes through direct binding to their promoters. PA0055, osaR, PA0057 and dsbM are in the same gene cluster, and we provide evidence that expression of these genes involved in oxidant tolerance is controlled by binding of OsaR to intergenic region between osaR and PA0057, which contain two divergent promoters. The gene cluster is also regulated by PA0055 via an indirect effect. We further discovered that OsaR formed intramolecular disulfide bonds when exposed to oxidative stress, resulting in a change of its DNA binding affinity. Taken together, our results indicate that OsaR is inactivated by oxidative stress and plays a role in the tolerance of P. aeruginosa to aminoglycoside and beta-lactam antibiotics. IMPORTANCE As opportunistic pathogen, Pseudomonas aeruginosa can cause serious infections which are hard to eradicate because of antibiotic resistance in immunodeficient patients. We found that OsaR is involved in oxidative stress and antibiotics resistance by regulation of downstream genes via redox state change. Research on factors affecting the transcriptional level of oxyR is very limited, but important since it has implications on antibiotic resistance. In this study, it was found that OsaR can indirectly inhibit transcription of oxyR. In addition the gene cluster composed of PA0055, osaR, PA0057 and dsbM was identified, and the associated regulatory mechanisms and functions were elucidated. Our work not only provides a mechanistic understanding of antibiotic tolerance regulation in P. aeruginosa, but also has significant implications for redox regulation in human pathogens in general.

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Clinical relevance, Speciation, and Antibiogram of Non -Diphtherial Corynebacteria isolated from various clinical samples in a tertiary care hospital in Zagazig, Egypt

10.51429/ejmm30207 ◽

2021 ◽

Vol 30 (2) ◽

pp. 43-49

Author(s):

Shymaa Yahia ◽

May M. Sami

Keyword(s):

Tertiary Care ◽

Resistance Rate ◽

University Hospital ◽

British Society ◽

Diffusion Method ◽

Clinical Samples ◽

Care Hospital ◽

Beta Lactam ◽

Beta Lactam Antibiotics ◽

Isolated Species

Background: The non-diphtherial Corynebacteria, also called “Coryneforms” bacteria are a diversified group of gram positive non sporing bacilli belonging to the genus Corynebacteria. Such bacteria are considered members of human microbiota (skin, respiratory and genital mucus membranes). Coryneform bacteria's pathogenic capacity has been undervalued until recently. Despite of frequently deemed as contaminants, these bacteria have been correlated to diverse clinical infections recently. Objectives: To isolate, speciate, and determine antimicrobial susceptibility pattern of clinically relevant non-diphtherial Corynebacteria from various clinical samples. Methodology: Different clinical samples (blood, urine, sputum, wound swabs, pus) collected from hospitalized patients attending at Zagazig University Hospital. The samples were processed and cultured as per conventional bacteriological methods. A total of 75 clinically relevant corynebacterial isolates exhibited speciation utilizing matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis and their antibiogram was done by disc diffusion method by means of combined guidelines of Clinical and Laboratory Standards Institute (CLSI) as well as British Society for Antimicrobial Chemotherapy (BSAC) because of lack of definite CLSI guidelines. Results: The mean age of the studied patients was 64.6 ± 14.9 years, 60% were male and 40% female. A total 75 clinically relevant Corynebacteria species were obtained from different clinical samples, including wound swabs and pus (53%), sputum (20%), and blood (17%). Forty two percent were isolated from ICUs. The most prevalent isolated species was C.amycolatum (27%), C. striatum (20%), and C.jeikieum (16%). Beta lactam antibiotics showed least activity against Corynebacteria species with resistance rate against penicillin 76% and ceftriaxone 72%, while all isolates exhibited uniform sensitivity (100%) against vancomycin as well as linezolid. Conclusion: This study showed isolation of different clinically relevant non-diaphterial Corynebacteria from different clinical samples with pus and wound swabs as the most common samples from which Corynebacteria were isolated. In particular, C.amycolatum was the most common isolated species. Beta lactam antibiotics (penicillin, ceftriaxone) showed the least activity while vancomycin and linezolid were the most active agents against nondiapdhterial Corynebacteria isolates. Herein, we confirm diphtheroids’ clinical importance among different infections that necessitate evaluating their susceptibility patterns to some common antibacterial agents for guide the best antibiotic to treat infections caused by these species.

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