Sequence Analyses and Phenotypic Characterization Revealed Multidrug Resistant Gene Insertions in the Genomic Region Encompassing Phase 2 Flagellin Encoding fljAB Genes in Monophasic Variant Salmonella enterica Serovar 4,5,12:i:- Isolates From Various Sources in Thailand

Salmonella enterica serovar 4,5,12:i:- (S. 4,5,12:i:-), a monophasic variant of Salmonella Typhimurium (STm) lacking the phase 2 flagellin encoding genes fljAB, has become increasingly prevalent worldwide. The increasing trends in multidrug resistant (MDR) S. 4,5,12:i:- prevalence also pose an important global health threat. Though many reports have characterized phenotypic and genotypic drug resistance of this serovar, few studies have characterized antimicrobial resistance of this serovar in Thailand. In this study, 108 S. 4,5,12:i:- isolates from various sources in Thailand and four international S. 4,5,12:i:- isolates were screened using polymerase chain reaction (PCR) to detect the presence of five target regions which are associated with antimicrobial resistant (AMR) genes, in the genomic region that contained fljAB genes in STm. We determined AMR phenotypes of all isolates by Kirby-Bauer disk diffusion method. Whole genome sequencing (WGS) was performed on 53 representative isolates (based on differences in the pulsed filed gel electrophoresis profiles, the sources of isolate, and the PCR and AMR patterns) to characterize the genetic basis of AMR phenotype and to identify the location of AMR determinants. Based on PCR screening, nine PCR profiles showing distinct deletion patterns of the five target regions have been observed. Approximately 76% of isolates (or 85 of 112 isolates), all of which were Thai isolates, contained five target regions inserted between STM2759 and iroB gene. A total of 21 phenotypic AMR patterns were identified with the predominant AmpST resistant phenotype [i.e., 84% (or 94 of 112) tested positive for resistance to ampicillin, streptomycin, and tetracycline], and 89% (or 100 of 112) were found to be MDR (defined here as resistant to at least three classes of tested antimicrobials). Using WGS data, a total of 24 genotypic AMR determinants belonging to seven different antimicrobial groups were found. AMR determinants (i.e., blaTEM–1, strB-A, sul2, and tetB, conferring resistance to ampicillin, streptomycin, sulfonamides, and tetracycline, respectively) were found to be inserted in a region typically occupied by the phase 2 flagellin encoding genes in STm. These resistant genes were flanked by a number of insertion sequences (IS), and co-localized with mercury tolerance genes. Our findings identify AMR genes, possibly associated with multiple IS26 copies, in the genetic region between STM2759 and iroB genes replacing phase 2 flagellin encoding fljAB genes in Thai S. 4,5,12:i:- isolates.

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Antibiotic Susceptibility Pattern of Salmonella Enterica serovars Typhi and Paratyphi A Isolated From Patients Suspected of Enteric Fever

Tribhuvan University Journal of Microbiology ◽

10.3126/tujm.v7i0.33791 ◽

2020 ◽

Vol 7 ◽

pp. 31-36

Author(s):

Dhirendra Niroula ◽

Jyotsna Shrestha ◽

Supriya Sharma ◽

Anjana Singh

Keyword(s):

Salmonella Enterica ◽

Antibiotic Susceptibility ◽

Enteric Fever ◽

Multidrug Resistant ◽

Diffusion Method ◽

Biochemical Tests ◽

Salmonella Spp ◽

Disk Diffusion Method ◽

Cross Sectional ◽

Microbiological Techniques

Objectives: The study aimed to assess the antibiotic susceptibility profile of Salmonella spp isolated from patients suspected of enteric fever. Methods: This cross-sectional prospective study was carried out from April to June, 2014among 484 patients clinically suspected of enteric fever visiting Bir Hospital, Kathmandu, Nepal. Blood sample collected from each patient was processed for culture in bile broth. Identification of Salmonella spp was done by conventional microbiological techniques including colony characteristics, Gram's staining and biochemical tests. Antibiotic susceptibility testing of identified isolates was done by Kirby-Bauer disk diffusion method following the 2014 CLS I guideline. Results: Out of 484 blood samples, 36 (7.43%) cases showed the growth of Salmonella spp; of which 27 (75%) were Salmonella enterica serovar Typhi (ST) and 9 (25%) were Salmonella enterica Paratyphi A (SPA). Among the Salmonella isolates, 5.55% were multidrug resistant and 41.66% were fluoroquinolone resistant. More than 80% of isolates were sensitive to chloramphenicol, amoxicillin, and cotrimoxazole whereas 58%, 50% and 6% of isolates were sensitive to fluoroquinolone antibiotics i.e. ciprofloxacin, ofloxacin and nalidixic acid respectively. All the isolates were susceptible to ceftazidime. All SPA and 89% of ST were sensitive to azithromycin. Conclusion: Higher percentage of susceptible isolates to chloramphenicol, cotrimoxazole, and amoxicillin suggests the reconsideration of these antibiotics for the treatment of enteric fever. Azithromycin can be considered as drug of choice for the treatment of enteric fever.

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Antibiogram, Prevalence of OXA Carbapenemase Encoding Genes, and RAPD-Genotyping of Multidrug-Resistant Acinetobacter baumannii Incriminated in Hidden Community-Acquired Infections

Antibiotics ◽

10.3390/antibiotics9090603 ◽

2020 ◽

Vol 9 (9) ◽

pp. 603

Author(s):

Waleed El-Kazzaz ◽

Lobna Metwally ◽

Reham Yahia ◽

Najwa Al-Harbi ◽

Ayat El-Taher ◽

...

Keyword(s):

Acinetobacter Baumannii ◽

Susceptibility Testing ◽

Multidrug Resistant ◽

Diffusion Method ◽

Disk Diffusion Method ◽

Extensively Drug Resistant ◽

Rapd Pcr ◽

High Prevalence ◽

Acinetobacter Spp ◽

Encoding Genes

Acinetobacter spp. has gained fame from their ability to resist difficult conditions and their constant development of antimicrobial resistance. This study aimed to investigate the prevalence, susceptibility testing, OXA carbapenemase-encoding genes, and RAPD-genotyping of multidrug resistant Acinetobacter baumannii incriminated in hidden community-acquired infections in Egypt. The antimicrobial susceptibility testing was assessed phenotypically using Kirby–Bauer disk diffusion method. Also, Modified-Hodge test (MHT) was carried out to detect the carbapenemases production. Multiplex-PCR was used to detect the carbapenemase-encoding genes. Furthermore, the genetic relationship among the isolated strains was investigated using RAPD fingerprinting. The bacteriological examination revealed that, out of 200 Gram-negative non-fermentative isolates, 44 (22%) were identified phenotypically and biochemically as Acinetobacter spp. and 23 (11.5%) were molecularly confirmed as A.baumannii. The retrieved A.baumannii strains were isolated from urine (69%), sputum (22%), and cerebrospinal fluid (csf) (9%). The isolated A. baumannii strains exhibited multidrug resistance and the production rates of carbapenemases were 56.5, 60.9, and 78.3% with meropenem, imipenem, and ertapenem disks, respectively. The blaOXA-24-like genes were the most predominant among the tested strains (65.2%), followed by blaOXA-23 (30.4%) and blaOXA-58 (17.4%), in addition, the examined strains are harbored IMP, VIM, and NDM genes with prevalence of 60.9, 43.5, and 13%, respectively, while KPC and GES genes were not detected. RAPD-PCR revealed that the examined strains are clustered into 11 different genotypes at ≥90% similarity. Briefly, to the best of our knowledge, this study is the first report concerning community-associated A. baumannii infections in Egypt. The high prevalence of hidden multidrug-resistant (MDR) and extensively drug-resistant (XDR) A.baumannii strains associated with non-hospitalized patients raises an alarm for healthcare authorities to set strict standards to control the spread of such pathogens with high rates of morbidity and mortality.

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Prevalence and Phenotypic and Genotypic Resistance Mechanisms of Multidrug-Resistant Pseudomonas aeruginosa Strains Isolated from Clinical, Environmental, and Poultry Litter Samples from the Ashanti Region of Ghana

Journal of Environmental and Public Health ◽

10.1155/2021/9976064 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Hayford Odoi ◽

Vivian Etsiapa Boamah ◽

Yaw Duah Boakye ◽

Christian Agyare

Keyword(s):

Phenylboronic Acid ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Diffusion Method ◽

Genotypic Resistance ◽

Disk Diffusion Method ◽

Ashanti Region ◽

Resistant Strains ◽

Synergy Test ◽

Encoding Genes

Background. Antibiotic resistance in bacteria is a major global health challenge. Reports on the prevalence of multidrug-resistant P. aeruginosa, a common pathogenic bacterium implicated in nosocomial infections and poultry diseases, are limited in Ghana. This study therefore sought to determine the prevalence of P. aeruginosa from hospitals, poultry farms, and environmental samples from the Ashanti region of Ghana. Methodology. Stool, urine, and blood samples from 364 patients from two hospitals in the Ashanti region of Ghana were randomly sampled. P. aeruginosa was isolated and confirmed using routine selective media and PCR-based oprL gene amplification. The Kirby-Bauer disk diffusion method employing EUCAST breakpoint values was used to identify multidrug-resistant strains. The occurrence of common antibiotic inactivating enzymes and resistance encoding genes and the assessment of strain efflux capacity were investigated with double disc synergy test (DDST), imipenem-EDTA synergy test, phenylboronic acid test, D-test, routine PCR, and ethidium bromide agar-cartwheel method. Results. A total of 87 (9.7%, n = 87/900) P. aeruginosa isolates were confirmed from the samples. 75% (n = 65/87) were resistant to more than one group of antipseudomonal agents, while 43.6% (n = 38/87) were multidrug-resistant (MDR). High prevalence of extended spectrum β-lactamases (84.2%), metallo-β-lactamases (34.1%), and AmpC inducible cephalosporinases (50%) was observed in the MDR strains. About 57.8% of the MDR strains showed moderate to very high efflux capacity. Class 1 integrons were detected in 89.4% of the MDR isolates but β-lactamase encoding genes (blaSHV, blaTEM, blaCTX-M, blaVIM, and blaIMP) were not detected. Conclusion. Surveillance of antibiotic-resistant strains of bacteria should be routinely conducted in clinical and veterinary practice in Ghana to inform selection of antibiotics for therapeutic use.

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ANTIMICROBIAL SUSCEPTIBILITY IN CULTURE POSITIVE ENTERIC FEVER

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v3i7.357 ◽

2019 ◽

Vol 3 (7) ◽

Author(s):

Dr. Manish Kulshrestha ◽

Dr. Anjali Kulshrestha

Keyword(s):

Bone Marrow ◽

Blood Culture ◽

Nalidixic Acid ◽

Antimicrobial Susceptibility ◽

Salmonella Enterica ◽

Enteric Fever ◽

Multidrug Resistant ◽

Bone Marrow Culture ◽

Diffusion Method ◽

Culture Positive

INTRODUCTION: Enteric fever includes typhoid and paratyphoid fever. Peak incidence is seen in children 5–15 years of age; but in regions where the disease is highly endemic, as in India, children younger than 5 years of age may have the highest infection rates. There are about 22 million new typhoid cases occur each year. Young children in poor, resource limited areas, who make up the majority of the new cases and there is a mortality figures of 215,000 deaths annually. A sharp decline in the rates of complications and mortality due to typhoid fever is observed as a result of introduction of effective antibiotic therapy since 1950s. MDR-ST became endemic in many areas of Asia, including India soon after multidrug-resistant strains of Salmonella enterica serotype typhi (MDR-ST) that were resistant to all the three first-line drugs then in use, namely chloramphenicol, amoxycillin and co-trimoxazole emerged in early 1990s. MATERIAL AND METHODS: Only blood culture or bone marrow culture positive cases were included. The patients with culture isolated enteric fever were included in the study. Antimicrobial susceptibility testing was carried out by disk diffusion method using antibiotic discs. The analysis of the antimicrobial susceptibility was carried out as per CLSI interpretative guidelines. RESULTS: A total of 82 culture positive cases were included in the present study. 80 culture isolates were from blood culture and 2 from the bone marrow culture. Salmonella entericasubspecies enterica serovartyphi (S typhi) was isolated from 67 (81.70%) patients while Salmonella enterica subspecies entericaserovarparatyphi (S paratyphi A) was isolated from 13 (15.85%) cases and 2 (2.44%) were Salmonella enterica subspecies entericaserovarschottmuelleri (S paratyphi B). Of the 82 cases 65(79.3%) isolates were resistant to ciprofloxacin, 17 (20.7%) were resistant to nalidixic acid, one (1.2%) case each was resistant to Cefotaxime and ceftriaxone, 2 (2.4%) were resistant to chloramphenicol, 10 (12.2%) were resistant and to cotrimoxazole 3 (3.7%) were resistant. CONCLUSION: In a culture positive cases 65(79.3%) isolates were resistant to ciprofloxacin and 17 (20.7%) were resistant to nalidixic acid. Multidrug resistant isolates were 65(79.3%).

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Antibiotic Resistance of Uropathogens Isolated from Patients Hospitalized in District Hospital in Central Poland in 2020

Antibiotics ◽

10.3390/antibiotics10040447 ◽

2021 ◽

Vol 10 (4) ◽

pp. 447

Author(s):

Barbara Kot ◽

Agata Grużewska ◽

Piotr Szweda ◽

Jolanta Wicha ◽

Urszula Parulska

Keyword(s):

Antibiotic Resistance ◽

Multidrug Resistant ◽

Diffusion Method ◽

Disk Diffusion Method ◽

Beta Lactamases ◽

E Coli ◽

Central Poland ◽

Resistance Patterns ◽

Extended Spectrum Beta Lactamases ◽

Tract Infections

The aim of this study was to determine antibiotic resistance patterns and the prevalence of uropathogenes causing urinary tract infections (UTIs) in patients hospitalized in January–June 2020 in central Poland. Antimicrobial susceptibility testing was performed using the disk-diffusion method. Escherichia coli (52.2%), Klebsiella pneumoniae (13.7%), Enterococcus faecalis (9.3%), E. faecium (6.2%), and Proteus mirabilis (4,3%) were most commonly isolated from urine samples. E. coli was significantly more frequent in women (58.6%) (p = 0.0089) and in the age group 0–18, while K. pneumoniae was more frequent in men (24.4%) (p = 0.0119) and in individuals aged 40–60 and >60. Gram-negative species showed resistance to ampicillin. K. pneumoniae were resistant to amoxicillin plus clavulanic acid (75.0%), piperacillin plus tazobactam (76.2%), cefotaxime (76.2%), cefuroxime (81.0%), ciprofloxacin (81.0%), and trimethoprim plus sulphamethoxazole (81.0%). Carbapenems were effective against all E. coli and P. mirabilis. Some K. pneumoniae (13.6%) produced metallo-β-lactamases (MBLs). E. coli (22.6%), K. pneumoniae (81.8%), and all E. faecium were multidrug-resistant (MDR). Some E. coli (26.2%), K. pneumoniae (63.6%), and P. mirabilis (14.3%) isolates produced extended-spectrum beta-lactamases (ESBL). Vancomycin-resistant E. faecium was also found. This study showed that the possibilities of UTIs therapy using available antibiotics become limited due to the increasing number of antibiotic-resistant uropathogens.

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The activity of different extracts from Panax quinquefolium L. cultures against pathogenic Staphylococcus aureus with respect to ginsenoside content

Archives of Biological Sciences ◽

10.2298/abs150330104s ◽

2015 ◽

Vol 67 (4) ◽

pp. 1277-1284 ◽

Cited By ~ 2

Author(s):

Monika Sienkiewicz ◽

Anna Głowacka ◽

Edward Kowalczyk ◽

Ewa Kochan

Keyword(s):

Staphylococcus Aureus ◽

Hairy Root ◽

Multidrug Resistant ◽

Clinical Isolates ◽

Diffusion Method ◽

Hairy Root Cultures ◽

Root Cultures ◽

Panax Quinquefolium ◽

Disk Diffusion Method ◽

Ginsenoside Content

Ginsenosides can be isolated from various cultures of Panax quinquefolium L., American ginseng. The aim of the study was to determine the antibacterial activity of extracts from leaves, stalks, hairy root cultures and field roots of P. quinquefolium L. containing ginsenosides against Staphylococcus aureus isolates obtained from various clinical materials. The agar well diffusion assay was used to evaluate microbial growth inhibition at various concentrations of extracts. The susceptibility of the clinical isolates to recommended antibiotics was determined with the disk-diffusion method. The results showed that the tested extracts inhibited the growth of all S. aureus clinical isolates, including MRSA (methicillin-resistant S. aureus) with MIC values ranging from 0.5 mg/mL to 1.7 mg/mL. The level of antimicrobial activity of extracts depends on the ginsenoside content. Both field roots and hairy root cultures represent excellent sources of these metabolites. Extracts with ginsenosides were found to inhibit multidrug-resistant staphylococci and can be a valuable complement to antistaphylococcal therapy.

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Prevalence, Risk Factors, and Antibiogram of Nontyphoidal Salmonella from Beef in Ambo and Holeta Towns, Oromia Region, Ethiopia

International Journal of Microbiology ◽

10.1155/2021/6626373 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Endrias Zewdu Gebremedhin ◽

Gezahegn Tafesse Soboka ◽

Bizunesh Mideksa Borana ◽

Lencho Megersa Marami ◽

Edilu Jorga Sarba ◽

...

Keyword(s):

Risk Factors ◽

Food Safety ◽

Antimicrobial Susceptibility ◽

Multidrug Resistant ◽

Animal Origin ◽

Diffusion Method ◽

Isolation And Identification ◽

Disk Diffusion Method ◽

Cross Sectional ◽

Food Of Animal Origin

Background. Salmonella has been recognized as a major cause of food-borne illness associated with the consumption of food of animal origin. The present cross-sectional study was conducted from December 2017 to May 2018 in Ambo and Holeta towns to assess the prevalence, risk factors, and antimicrobial susceptibility patterns of nontyphoidal Salmonella isolates from raw beef samples from abattoirs, butchers, and restaurants in Ambo and Holeta towns, Oromia region, Ethiopia. Methods. A total of 354 beef samples were collected from abattoirs, butchers, and restaurants. Salmonella isolation and identification were carried out using standard bacteriological methods recommended by the International Organization for Standardization. Antimicrobial susceptibility testing was performed using the disk diffusion method. Besides, a structured questionnaire was used to collect sociodemographic data and potential risk factors for contamination of meat. Chi-square tests and logistic regression were used for data analyses. Results. Of the total 354 meat samples examined, 20 (5.7%, 95% confidence interval (CI): 3.5–8.6) were positive for Salmonella. Two serotypes belonging to S. typhimurium (11 isolates) and I:4,5,12: i:- (9 isolates) were identified. The Salmonella detection rate in abattoirs, butchers, and restaurants was 4.2% (5/118), 8.5% (10/118), and 4.2% (5/118), respectively. The antimicrobial susceptibility test showed that 40%, 30%, and 20% of the Salmonella isolates were resistant to azithromycin, amoxicillin, and ceftriaxone, respectively. The odds of Salmonella isolation when meat handlers are illiterate were 7.8 times higher than those when they are educated to the level of secondary and above ( P = 0.032 ). Similarly, the likelihood of Salmonella isolation was 6.3 and 7.6 times higher among workers of butcher and restaurants, respectively, who had no training ( P = 0.003 ) and no knowledge ( P = 0.010 ) on food safety and hygiene. Conclusions. The study showed widespread multidrug-resistant Salmonella isolates in the study areas. Therefore, raw meat consumption and indiscriminate use of antimicrobial drugs should be discouraged. Provision of food safety education for meat handlers and further surveillance of antimicrobial-resistant isolates are suggested.

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Molecular Detection and Antibiotyping of Multidrug-Resistant Salmonella Isolated from Houseflies in a Fish Market

Pathogens ◽

10.3390/pathogens8040191 ◽

2019 ◽

Vol 8 (4) ◽

pp. 191 ◽

Cited By ~ 5

Author(s):

Sobur ◽

Hasan ◽

Haque ◽

Mridul ◽

Noreddin ◽

...

Keyword(s):

Molecular Detection ◽

Multidrug Resistant ◽

Diffusion Method ◽

Resistant Bacteria ◽

Salmonella Spp ◽

Disk Diffusion Method ◽

Antibiotic Resistant ◽

Fish Market ◽

Pcr Method ◽

High Level

Houseflies (Musca domestica) are well-known mechanical vectors for spreading multidrug-resistant bacteria. Fish sold in open markets are exposed to houseflies. The present study investigated the prevalence and antibiotypes of multidrug-resistant (MDR) Salmonella spp. in houseflies captured from a fish market. Direct interviews with fish vendors and consumers were also performed to draw their perceptions about the role of flies in spreading antibiotic-resistant bacteria. A total of 60 houseflies were captured from a local fish market in Bangladesh. The presence of Salmonella spp. was confirmed using PCR method. Antibiogram was determined by the disk diffusion method, followed by the detection of tetA, tetB, and qnrA resistance genes by PCR. From the interview, it was found that most of the consumers and vendors were not aware of antibiotic resistance, but reported that flies can carry pathogens. Salmonella spp. were identified from the surface of 34 (56.7%) houseflies, of which 31 (91.2%) were found to be MDR. This study revealed 25 antibiotypes among the isolated Salmonella spp. All tested isolates were found to be resistant to tetracycline. tetA and tetB were detected in 100% and 47.1% of the isolates, respectively. Among the 10 isolates phenotypically found resistant to ciprofloxacin, six (60%) were found to be positive for qnrA gene. As far as we know, this is the first study from Bangladesh to report and describe the molecular detection of multidrug-resistant Salmonella spp. in houseflies in a fish market facility. The occurrence of a high level of MDR Salmonella in houseflies in the fish market is of great public health concerns.

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Essential Oil from Origanum vulgare Completely Inhibits the Growth of Multidrug-Resistant Cystic Fibrosis Pathogens

Natural Product Communications ◽

10.1177/1934578x1601100641 ◽

2016 ◽

Vol 11 (6) ◽

pp. 1934578X1601100 ◽

Cited By ~ 4

Author(s):

Giovanna Pesavento ◽

Valentina Maggini ◽

Isabel Maida ◽

Antonella Lo Nostro ◽

Carmela Calonico ◽

...

Keyword(s):

Cystic Fibrosis ◽

Essential Oil ◽

Multidrug Resistant ◽

Diffusion Method ◽

Achromobacter Xylosoxidans ◽

Bacterial Strains ◽

Origanum Vulgare ◽

Disk Diffusion Method ◽

Wide Range

Essential oils (EOs) are known to inhibit the growth of a wide range of microorganisms. Particularly interesting is the possible use of EOs to treat multidrug-resistant cystic fibrosis (CF) pathogens. We tested the essential oil (EO) from Origanum vulgare for in vitro antimicrobial activity, against three of the major human opportunistic pathogens responsible for respiratory infections in CF patients; these are methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia and Achromobacter xylosoxidans. Antibiotic susceptibility of each strain was previously tested by the standard disk diffusion method. Most strains were resistant to multiple antibiotics and could be defined as multi-drug-resistant (MDR). The antibacterial activity of O. vulgare EO (OEO) against a panel of 59 bacterial strains was evaluated, with MIC and MBC determined at 24, 48 and 72 hours by a microdilution method. The OEO was effective against all tested strains, although to a different extent. The MBC and MIC of OEO for S. aureus strains were either lower or equal to 0.50%, v/v, for A. xylosoxidans strains were lower or equal to 1% and 0.50%, v/v, respectively; and for S. maltophilia strains were lower or equal to 0.25%, v/v. The results from this study suggest that OEO might exert a role as an antimicrobial in the treatment of CF infections.

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Antibiotic Resistance of Enterobacteriaceae Isolated from Fresh Fruits and Vegetables and Characterization of their AmpC β-Lactamases

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-089 ◽

2019 ◽

Vol 82 (11) ◽

pp. 1857-1863 ◽

Cited By ~ 2

Author(s):

ZAHRA S. AL-KHAROUSI ◽

NEJIB GUIZANI ◽

ABDULLAH M. AL-SADI ◽

ISMAIL M. AL-BULUSHI

Keyword(s):

Antibiotic Resistance ◽

Fruits And Vegetables ◽

Multidrug Resistant ◽

Diffusion Method ◽

Resistant Bacteria ◽

Disk Diffusion Method ◽

Antibiotic Resistant ◽

Amoxicillin Clavulanic Acid ◽

Clinically Significant ◽

Enterobacter Asburiae

ABSTRACT Enterobacteria may gain antibiotic resistance and be potent pathogens wherever they are present, including in fresh fruits and vegetables. This study tested the antibiotic resistance of enterobacteria isolated from 13 types of local and imported fresh fruits and vegetables (n = 105), using the standard Kirby-Bauer disk diffusion method. Phenotypic and genotypic characterizations of AmpC β-lactamases were determined in cefoxitin-resistant isolates. Ten percent of the enterobacteria tested (n = 88) were pansusceptible, 74% were resistant to at least one antibiotic, and 16% were multidrug resistant. Enterobacteria isolates showed the highest antibiotic resistance against ampicillin (66%), cephalothin (57%), amoxicillin–clavulanic acid (33%), cefoxitin (31%), tetracycline (9%), nalidixic acid (7%), trimethoprim (6%), and kanamycin (5%). Three isolates showed intermediate resistance to the clinically important antibiotic imipenem. Escherichia coli isolated from lettuce exhibited multidrug resistance against five antibiotics. Fifteen isolates were confirmed to have AmpC β-lactamase, using the inhibitor-based test and the antagonism test; the latter test confirmed that the enzyme was an inducible type. Four types of ampC β-lactamase genes (CIT, EBC, FOX, and MOX) were detected in eight isolates: four Enterobacter cloacae isolates and one isolate each of Citrobacter freundii, Enterobacter asburiae, Enterobacter hormaechei, and Enterobacter ludwigii. It was concluded that fresh fruits and vegetables might play a role as a source or vehicle for transferring antibiotic-resistant bacteria that might spread to other countries through exportation. The clinically significant AmpC β-lactamase was rarely documented in the literature on bacteria isolated from fruits and vegetables, and to our knowledge, this is the first report on the detection of an inducible type in such commodities.

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