Multiple Antibiotic Resistance Index Values Research Articles

Molecular characterization and antibiotics resistance of Aeromonas species isolated from farmed African catfish Clarias gariepinus Burchell, 1822

BackgroundAeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public health risks. This study aimed to investigate the prevalence, phenotypic and molecular characteristics of Aeromonas species isolated from farmed Clarias gariepinus using 16 S rRNA sequencing. Additionally, their antibiogram and multiple antibiotic resistance index were determined using a disc diffusion test.ResultsA total of 230 Aeromonas strains were isolated from Clarias gariepinus with 40.9% obtained from diseased fish, and 25% isolated from apparently healthy ones. Five different species including Aeromonas caviae, Aeromonas veronii, Aeromonas hydrophila, Aeromonas dhakensis and Aeromonas enteropelogenes were fully identified and genetically characterized. Based on the available literature, this is the first report of Aeromonas enteropelogenes from the study area. The phylogenetic analysis showed genetic heterogeneity and distance within the species and the reference strains. The multiple resistant Aeromonas species were susceptible to ciprofloxacin, gentamycin, and florfenicol. The Aeromonas species’ multiple antibiotic resistance index values varied between 0.20 and 0.80 and were isolated from the farms where antibiotics were intensively used.ConclusionsThe diversity of multidrug-resistant Aeromonas species isolated from fish farms is a major threat to fish production giving us more understanding of epidemiology and the multidrug Aeromonas species with a MAR index of greater than 0.2 were isolated from farms where antibiotic use was widespread. As a result, a considerably increased danger of multiple antibiotic resistance spreading to the fish culture environment may impact aquaculture production. Hence there is a need for appropriate and monitored drug usage.

Antibiotypes and genetic characteristics of fluoroquinolone- and beta-lactam-resistant Escherichia coli isolated from food-producing animals

Background and Aim: Farm animals, including cattle, have been implicated as antimicrobial-resistant bacterial pathogen reservoirs. This study aimed to determine the antimicrobial resistance profiles and genetic characteristics of cattle colonized by fluoroquinolone-resistant and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in Ebonyi state, Nigeria. Materials and Methods: We randomly collected 100 fresh fecal samples from 100 cattle in major abattoirs and analyzed the samples using standard microbiological methods. Isolates were further characterized by polymerase chain reaction (PCR) using 16S rRNA sequence primers. Phenotypic detection of ESBL production was performed using the double disk synergy test. Antimicrobial susceptibility profiles of ESBL-producing Escherichia coli were determined using the disk diffusion method, whereas molecular characterization of ESBL- and fluoroquinolone-resistant genes was performed by PCR using specific primers. Results: A total of 20 (20%) ESBL-producing E. coli were isolated from 100 animal fecal samples. Isolates were generally multidrug-resistant (MDR) with a resistance rate of 100% to 45% to trimethoprim-sulfamethoxazole, tetracycline, amoxicillin, cephalosporins, and ciprofloxacin. The average multiple antibiotic resistance index values of the isolates ranged from 0.5 to 0.8. BlaTEM (75%), followed by blaCTX-M (20%) and blaSHV (5.0%) was the most predominant ESBL gene among the isolates. The Aac-lb-6-cr fluoroquinolone-resistant gene was harbored by 90% of the isolates, whereas Qnr was absent. Conclusion: This study showed a high frequency of MDR ESBL-producing E. coli harboring ESBL and fluoroquinolone-resistant genes in fecal samples of cattle with serious public health consequences if not adequately addressed. Keywords: Escherichia coli, extended-spectrum beta-lactamase genes, fluoroquinolone resistance genes, cattle, multidrug-resistance.

Diversity of Antibiotic-resistant of Tentative Motile Aeromonas Species Isolated From Clarias gariepinus (Burchell 1822) Cultured in Earthen Ponds

Background: Aeromonas species is one of the most important causes of diseases in Clarias gariepinus, a public health threat with significant economic losses. Objectives: In this research, the prevalence and variety of Aeromonas species isolated from C. gariepinus cultured in an earthen pond were investigated, as well as the antibiogram and multiple antibiotic resistance index Methods: Aeromonas species were isolated by culture and biochemical test and confirmed using a Microbact 24E kit. The antibiotic susceptibility to 10 antibiotics was determined using the Kirby-Bauer disk diffusion method. Results: Aeromonas species were isolated with a prevalence of 43.1% with 4 different phenospecies with the highest prevalence of 46(24 %) for Aeromonas hydrophila followed by 15(7.8%) for Aeromonas caviae, then 10(5.2%) for Aeromonas veronii sobria, and the least was observed for Aeromonas veronii veronii 6(3.1%). The Aeromonas species showed high resistance to amoxicillin, ampicillin, colistin sulfate, oxytetracycline, trimethoprim/sulfamethoxazole, and penicillin, with varying resistant patterns, and the multiple antibiotic resistance index values ranged between 0.20 and 0.80. Conclusion: There was a diversity of Aeromonas species associated with multiple antibiotic-resistant leading to the wide spread of antimicrobial resistance. Therefore, there is a need to control the use of antibiotics and ensure the effective use of biosecurity and preventive management measures in fish farms.

High prevalence of antibiotic-resistant and metal-tolerant cultivable bacteria in remote glacier environment

Studies of antibiotic-resistant bacteria (ARB) have mainly originated from anthropic-influenced environments, with limited information from pristine environments. Remote cold environments are major reservoirs of ARB and have been determined in polar regions; however, their abundance in non-polar cold habitats is underexplored. This study evaluated antibiotics and metals resistance profiles, prevalence of antibiotic resistance genes (ARGs) and metals tolerance genes (MTGs) in 38 ARB isolated from the glacier debris and meltwater from Baishui Glacier No 1, China. Molecular identification displayed Proteobacteria (39.3%) predominant in debris, while meltwater was dominated by Actinobacteria (30%) and Proteobacteria (30%). Bacterial isolates exhibited multiple antibiotic resistance index values > 0.2. Gram-negative bacteria displayed higher resistance to antibiotics and metals than Gram-positive. PCR amplification exhibited distinct ARGs in bacteria dominated by β-lactam genes blaCTX-M (21.1–71.1%), blaACC (21.1–60.5%), tetracycline-resistant gene tetA (21.1–60.5%), and sulfonamide-resistant gene sulI (18.4–52.6%). Moreover, different MTGs were reported in bacterial isolates, including mercury-resistant merA (21.1–63.2%), copper-resistant copB (18.4–57.9%), chromium-resistant chrA (15.8–44.7%) and arsenic-resistant arsB (10.5–44.7%). This highlights the co-selection and co-occurrence of MTGs and ARGs in remote glacier environments. Different bacteria shared same ARGs, signifying horizontal gene transfer between species. Strong positive correlation among ARGs and MTGs was reported. Metals tolerance range exhibited that Gram-negative and Gram-positive bacteria clustered distinctly. Gram-negative bacteria were significantly tolerant to metals. Amino acid sequences of blaACC,blaCTX-M,blaSHV,blaampC,qnrA, sulI, tetA and blaTEM revealed variations. This study presents promising ARB, harboring ARGs with variations in amino acid sequences, highlighting the need to assess the transcriptome study of glacier bacteria conferring ARGs and MTGs.

Antimicrobial resistance and antagonistic features of bivalve-associated Vibrio parahaemolyticus from the south-west coast of India.

Vibrio parahaemolyticus, a potent human and aquatic pathogen, is usually found in estuaries and oceans. Human illness is associated with consuming uncooked/partially cooked contaminated seafood. The study on bivalve-associated V. parahaemolyticus revealed that the post-monsoon season had the highest bacterial abundance (9 ± 1.5 log cfu) compared to the monsoon season (8.03 ± 0.56 log cfu). Antimicrobial resistance (AMR) profiling was performed on 114 V. parahaemolyticus isolates obtained from bivalves. The highest AMR was observed against ampicillin (78%). Chloramphenicol was found to be effective against all the isolates. Multiple antibiotic resistance index values of 0.2 or higher were detected in 18% of the isolates. Molecular analysis of antimicrobial resistant genes (ARGs) revealed the high prevalence (100%) of the TEM-1 gene in the aquatic environment. After plasmid profiling and curing, 41.6% and 100% of the resistant isolates were found to be sensitive to ampicillin and cephalosporins, respectively, indicating the prevalence of plasmid-associated ARGs in the aquatic environment. A study to evaluate the antagonistic properties of Bacillus subtilis, Pseudomonas aeruginosa, and Bacillus amyloliquefaciens against V. parahaemolyticus isolates identified the potential of these bacteria to resist the growth of V. parahaemolyticus.

The Prevalence of Extended Spectrum Beta Lactamase Producing Citrrobacter Freundii and Pprovidencia Stuartii from Medical Laboratories in Parts of Lagos State, Nigeria

Citrobacter freundii and Providencia stuartii are members of the family Enterobacteriaceae which are emerging as important Extended Spectrum Beta Lactamase (ESBL) producing pathogens. This study was aimed to determine the prevalence of ESBL and carbapenemase production in C. freundii and P. stuartii. from laboratories in the northwest of Lagos. A total of 134 isolates were obtained from laboratories. Isolate identification, antibiotics susceptibility testing, and phenotypic detection of ESBL production were done using standardized procedures. Multiplex polymerase chain reaction (PCR) was performed on ESBL producing isolates to detect blaTEM, blaSHV, blaCTX-M, blaKPC, blaVIM, blaIMP and blaOXA. Out of 134 isolates 15 (11.2%) were Citrobacter freundii and only 2 (1.5%) were of the Providencia genus both of which were Providencia rettgeri and Providencia stuartii. A total of 9 (60%) tested positive for the production of Extended Spectrum Beta Lactamase (ESBL) enzyme while only Providencia stuartii of the Providencia genus also produced ESBL. Also, 8 (47%) of the initial Citrobacter and Providencia isolates produced carbapenemase Molecular characterization showed that 4 (44.4%) and 1 (100%) of the Citrobacter freundii and Providencia stuartii isolates respectively, displayed the presence of CTX-M gene while 2 (20%) of all ESBL producing isolates also possessed SHV gene including 1 (11.1%) of ESBL producing Citrobacter freundii and 1 (100%) of ESBL producing Providencia stuartii. Antibiotic susceptibility testing showed that Citrobacter freundii displayed the highest resistance to Ceftazidime and Cefotaxime at 71.4% and the least resistance to Amoxicillin-Clavulanate at 28.6%. Providencia stuartii also displayed absolute resistance (100%), to cefotaxime and ciprofloxacin and absolute susceptibility (100%) to Ceftazidime. Also, Citrobacter freundii showed the same resistance patterns with 57.1% resistance to Gentamicin, Cefuroxime and Ceftriaxone antibiotics while Providencia stuartii showed varied resistance patterns with absolute resistance (100%), absolute susceptibility (100%) and absolute resistance (100%) to Gentamicin, Cefuroxime and Ceftriaxone antibiotics respectively. In conclusion, the Multiple Antibiotic Resistance Index values of both bacterial genera showed that 70.6% were from High-Risk sources indicating that the majority of bacteria analysed were from environments where they have been subjected to a high burden of antibiotic exposure.

Molecular Evidence for Occurrence of Heavy Metal and Antibiotic Resistance Genes Among Predominant Metal Tolerant Pseudomonas sp. and Serratia sp. Prevalent in the Teesta River.

Riverine ecosystems polluted by pharmaceutical and metal industries are potential incubators of bacteria with dual resistance to heavy metals and antibiotics. The processes of co-resistance and cross resistance that empower bacteria to negotiate these challenges, strongly endorse dangers of antibiotic resistance generated by metal stress. Therefore, investigation into the molecular evidence of heavy metal and antibiotic resistance genes was the prime focus of this study. The selected Pseudomonas and Serratia species isolates evinced by their minimum inhibitory concentration and multiple antibiotic resistance (MAR) index showed significant heavy metal tolerance and multi-antibiotic resistance capability, respectively. Consequently, isolates with higher tolerance for the most toxic metal cadmium evinced high MAR index value (0.53 for Pseudomonas sp., and 0.46 for Serratia sp.) in the present investigation. Metal tolerance genes belonging to PIB-type and resistance nodulation division family of proteins were evident in these isolates. The antibiotic resistance genes like mexB, mexF and mexY occurred in Pseudomonas isolates while sdeB genes were present in Serratia isolates. Phylogenetic incongruency and GC composition analysis of PIB-type genes suggested that some of these isolates had acquired resistance through horizontal gene transfer (HGT). Therefore, the Teesta River has become a reservoir for resistant gene exchange or movement via selective pressure exerted by metals and antibiotics. The resultant adaptive mechanisms and altered phenotypes are potential tools to track metal tolerant strains with clinically significant antibiotic resistance traits.

Qualitative Risk Assessment of Microbial Indicators in the Lower Reaches of Meenachil River, Kerala, India

Pristine natural freshwater resources being severely contaminated by microbiological pollutants is still a big issue in many parts of the world. In the present study, water samples taken from the upstream, midstream, and downstream reaches of the Meenachil River were analysed for the presence of microbial pollution indicators such as faecal coliforms (FC), faecal streptococci (FS), and Eschericia coli. The E. coli isolates were subjected to antimicrobial susceptibility tests and the multiple antibiotic resistance (MAR) indexes were calculated so as to delineate the potential risk posed by infections to humans and animals using the river for routine potable and recreational purposes. E. coli was consistently isolated from all the samples collected from the different zones of the river. Other faecal coliforms such as Klebsiella oxytoca, Citrobacter koseri, Enterobacter, Proteus vulgaricus, and Shigella boydii were also identified. Higher FC/FS ratios were noticed for the midstream and the downstream sites indicating the contamination from high-risk sources such as human and anthropogenic domestic wastes. The MAR index values of E. coli isolates ranged from 0.33 upstream, 0.416 for midstream and 0.583 for the downstream reaches. Given that E. coli is an ideal indicator of faecal pollution, their existence and extended survival of multiple antibiotic resistance natural freshwater pose a potential risk for the consumers. Rapid urbanization and resultant waste drainage in the downstream stretches of the river might have accelerated the deterioration of the water quality up to a certain extent. Furthermore, the riverine system as it flows downstream loses its self-purification capacity due to the loss of natural water drifts. This may be attributed to the periodic shutdown of the salinity barrier, Thanneermukkam Bund in the confluence zone of the river which results in a temporary stagnation of the running waters in the lower stretches.

Prevalence of Multiple Drug-Resistant Bacteria in the Main Campus Wastewater Treatment Plant of Wolaita Sodo University, Southern Ethiopia.

Wastewater treatment plants (WWTPs) are important reservoirs for the development of drug resistance and a potential route for the dissemination of antibiotic resistance genes (ARGs) in the environment. One of the most serious challenges in Ethiopia is the widespread emergence of antibiotic resistance among bacterial pathogens. The bacteria were isolated between September 2018 and May 2019 from the main campus of Wolaita Sodo University in Southern Ethiopia. Using an enrichment process and selective media isolation, 380 wastewater treatment plant samples were collected and screened for the presence of various bacterial isolates. Of a total of 380 wastewater treatment samples, 136 were isolated. Positive prevalence was documented in 136 sample isolates of bacteria from six genera. Escherichia coli 34 (8.94%), Salmonella spp. 15 (3.94%), Shigella spp. 32 (8.42%), Staphylococcus aureus 23 (6.05%), Pseudomonas aeruginosa 21 (5.52%), and Proteus spp. 11 (2.89%). The general prevalence of bacterial isolates was assessed, and 136 (37.58%) samples tested positive for culture. Furthermore, isolates were used to determine sensitivity/resistance patterns using the Kirby-Bauer disc diffusion method and the agar well diffusion technique, respectively. Multiple drug resistance isolates and multiple values of the antibiotic resistance index were evaluated and recorded according to the resistant pattern. Some organisms were sensitive to sparfloxacin and tobramycin, while Staphylococcus aureus was sensitive to methicillin and others showed the highest resistance. At least four of the seven antibiotic classes were found to be resistant to multiple drug resistance isolates, and some classes of antibiotics were found to be highly sensitive to these isolates. Multiple antibiotic resistance index values ranged from 0.37 to 0.75, with Salmonella spp., Shigella spp., and Staphylococcus aureus having the highest score values. The current study has shown that some of the bacterial isolates were resistant to common antibiotics. Therefore, it is recommended that the emergence of multiple drug resistance increased rapidly, pathogenic bacteria inappropriate treated wastewater treatment plant systems were continuously contaminated, and bacterial resistance increased day by day as a result of environmental factors. As a result, due to the serious challenges facing the community's health, multiple drug-resistant prevention and control strategies must be implemented.

Multidrug resistance and class 1 integron presence in Escherichia coli isolates from a polluted drainage ditch’s water

ABSTRACT The impact of contamination of water drainage ditches in the development of antibiotic-resistant bacteria has been scarcely studied in Mexico. In this regard, 101 isolates of E. coli were obtained from water samples from a ditch in Sinaloa, during one year. The antimicrobial resistant profiles, the presence of the class 1 integron and evolutionary relationship of intI1 sequences were determined. The 47.5% of strains were resistant and 5.9% multidrug resistant (MDR) with an average multiple antibiotic resistance index value of 0.45. The highest resistance was registered with β-lactam (39.6%) and quinolone (9.9%). The intI1 gene was detected in 11.9% of the isolates, and no association with MDR was found. Sequence were associated with human and animal host isolates. MDR E. coli isolates with intI1 gene highlight the potential risk of the ditch’s water to human health. An attenuation effect of MDR E. coli isolates in the outlet water was observed.

Analysis of antibiotic resistance and virulence patterns inKlebsiella pneumoniaeisolated from human urinary tract infections in India

In this study, 504 urine samples collected from patients suffering from urinary tract infection (UTIs) were screened for the presence of Klebsiella pneumoniae. The overall occurrence of Klebsiella spp. and K. pneumoniae was found to be 23·2% (117/504) and 16·8% (85/504) respectively. Antibiotic susceptibility testing of 85 K. pneumoniae isolates was carried out by disc diffusion which revealed alarming levels of antibiotic resistance (ABR). Antimicrobial resistance was prominently observed against cefpodoxime (76·47%) followed by ampicillin (70·59%), ceftriaxone (52·94%), cefoxitin (50·59%), amoxyclav (48·24%), ofloxacin (45·88%), cefotaxime (44·71%), cefepime (43·53%) and doxycycline hydrochloride (40%). A small percentage of strains also exhibited resistance to other antimicrobials in the range of 7-35%. Around 77·6% of the isolates were found to be resistant to three or more antibiotic classes and 66·7% of the isolates had multiple antibiotic resistance index values >0·2. Screening of virulence genes in 85 K. pneumoniae isolates revealed that uge gene was the most predominant (11/85, 12·9%), followed by rmpA (9/85, 10·5%), kfu (4/85, 4·7%) and aerobactin genes (2/85, 2·35%). Further, the overall percentage of biofilm producers were found to be 17·65% (15/85). This study warrants hospitals and health care centres to reduce misuse of antibiotics and manage UTI with appropriate treatment after performing antibiotic susceptibility testing.

Antibiotic resistance in shellfish and major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea.

Shellfish-growing areas in marine environments are affected by pollutants that mainly originate from land, including streams, domestic wastewater, and the effluents of wastewater treatment plants (WWTPs), which may function as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The objective of this study was to identify the occurrence and distribution of antibiotic resistance at five oyster sampling sites and 11 major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Culture-based methods were used to estimate the diversity and abundance of antibiotic-resistant Escherichia coli strains isolated from oysters and major inland pollution sources. The percentages of ARB and multiple antibiotic resistance index values were significantly high in discharge water from small fishing villages without WWTPs. However, the percentages of antibiotic-resistant E. coli isolates from oysters were low, as there was no impact from major inland pollutants. Fourteen ARGs were also quantified from oysters and major inland pollution sources. Although most ARGs except for quinolones were widely distributed in domestic wastewater discharge and effluent from WWTPs, macrolide resistance genes (ermB and msrA) were detected mainly from oysters in Kamak Bay. This study will aid in tracking the sources of antibiotic contamination in shellfish to determine the correlation between shellfish and inland pollution sources.

Assessment of the Microbial Quality of Braised Products from Bangangte City and Antibiotic Susceptibility of Selected Pathogens Isolated Therein

The present study had as objective to assess the microbiological quality and profile of some braised products and their accompanying soups sold in the city of Bangangte (Cameroon) and evaluate the antibiotic susceptibility of selected pathogens isolated in these products. An investigation was conducted in three locations in city of Bangangte in order to assess the environment and working conditions as well as the respect of good hygiene practices. Then, samples of braised fish (05) and its soups (05), and braised chicken (05) and its soups (05) were collected from six vendors in each location. The samples (360) were submitted to microbiological analyses and the isolates were identified at species level using API gallery. The susceptibility of the isolates to 14 antibiotics were tested. The 72 participants involved in this study declared having knowledge on hygiene despite the fact that, most of them had no formal education and do not apply good hygiene practices. Microbiological analyses revealed the poor quality of all the samples of braised products. Fecal coliforms and staphylococci counts higher than the values recommended by norms demonstrated the non-respect of good hygiene and manufacturing practices during the braising activity. The 169 strains isolated from these products belonged to 12 different species: Enterobacter gergoviae, Enterobacter spp., Morganella morganiae, Yersinia enterolitica, Yersinia frederiksenii, Staphylococcus aureus, Staphylococcus epidermitidis, Staphylococcus spp., Clostridium spp., Klebsiella pneumoniae, Enterobacter aerogene, and Proteus mirabilis. Strains which could be considered as marker of braised fish sold in the city of Bangangte were Yersinia enterolitica, Staphylococcus aureus and Klebsiella pneumonia while for braised chicken, they were Yersinia enterolitica, Staphylococcus aureus and Proteus mirabilis. The antibiotic susceptibility test performed on these pathogens revealed that they were resistant with 93.75% having multiple antibiotic resistance index values greater than 0.2. We conclude that the microbiological quality of braised products is poor and we suggest to producers to applicate the good hygiene practices. For breeders, we suggest respecting withdrawal periods and the better use of antibiotics.

Effect of water reservoirs types on the prevalence and antibiotic resistance profiles of Pseudomonas aeruginosa isolated from bathroom water in hospitals.

This study was aimed to isolate and characterize Pseudomonas aeruginosa antibiotic resistance profiles that isolated from bathroom water of five hospitals in Bandung, Indonesia, with different types of water reservoirs. Total of 25 water samples from bathrooms of five hospitals were collected and analyzed for the existence of P. aeruginosa colonies on the surface of MacConkey agar media using a streak plate method and identified using phenotypic identification and a series of biochemical tests. All P. aeruginosa isolates were tested against ceftazidime, piperacillin/tazobactam, ciprofloxacin, meropenem, and gentamicin containing in paper disc, using the agar diffusion method. Of all samples, the total number of P. aeruginosa isolates was less than that of non-P. aeruginosa. In hospitals that use permanent bathtubs, a greater total bacterial count was obtained than those using pails. From 110 isolates, 14.54% were multidrug resistance antibiotics. The majority of the resistant isolates were from hospital B with permanent bathtubs. Of 25 isolates from that hospital, P. aeruginosa isolates were resistant to ceftazidime (20%), piperacillin/tazobactam (4%), ciprofloxacin (20%), and gentamicin (20%). The multiple antibiotic resistance index value of P. aeruginosa isolates was 0.4–0.6. Thus, it can be concluded that the bathroom wáter in the hospital with permanent bathtubs were potential reservoirs of antibiotic-resistant P. aeruginosa.

Enhanced Antibacterial Activity of Silver Nanoparticles Combined with Hydrogen Peroxide Against Multidrug-Resistant Pathogens Isolated from Dairy Farms and Beef Slaughterhouses in Egypt.

PurposeThe last few decades have witnessed a rapid and global increase in multidrug-resistant bacteria (MDR) emergence.MethodsThe aim of the current study is to isolate the most common MDR bacteria from dairy farms and beef slaughterhouses followed by evaluation of their antimicrobial resistance pattern and assessment of the antibacterial activity of AgNPs-H2O2 as an alternative to conventional antibiotics. In this regard, 200 samples were collected from two dairy farms and one beef slaughterhouse located in Dakhliya Governorate, Egypt.ResultsInterestingly, out of 120 collected samples from dairy farms, the prevalence of the isolated strains was 26.7, 23.3, 21.7, 16.7, and 11.7% for S. typhimurium, E. coli O157:H7, L. monocytogenes, K. pneumoniae and P. aeruginosa, respectively. Meanwhile, the overall prevalence was 30, 25, 22.5, 17.5, and 5% for E. coli O157:H7, L. monocytogenes, S. typhimurium, P. aeruginosa, and K. pneumoniae, respectively, for the 80 samples collected from a beef slaughterhouse. The antimicrobial susceptibility pattern elucidated that all isolated strains exhibited resistance to at least four of the tested antimicrobials, with multiple-antibiotic resistance index values (MAR) ranging between 0.44 and 0.88. Furthermore, the commercial AgNPs-H2O2 product was characterized by transmission electron microscopy (TEM) and zeta potential that showed spherical particles with a surface charge of −0.192 mV. The antimicrobial activity of synergized nano-silver (AgNP) with H2O2 product toward MDR strains was assessed via measuring minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill curve.ConclusionThe present data report high prevalence rates of MDR pathogens in dairy farms and abattoirs. More importantly, AgNPs-H2O2 exerted broad-spectrum bactericidal activity toward MDR bacterial strains, suggesting their promising usage as safe, ecofriendly, cost-effective antibacterial agents. To our knowledge, this study is a pioneer in investigating the potential alternative antimicrobial role of silver nanoparticles for control of multiple drug-resistant pathogens in Egypt.

Occurrence of Virulence Factors and Antibiotic and Heavy Metal Resistance in Vibrio parahaemolyticus Isolated from Pacific Mackerel at Markets in Zhejiang, China

Vibrio parahaemolyticus is a widespread bacterium in the marine environment and is one of the leading causes of food-derived bacterial poisoning in humans worldwide. The main objective of this study was to determine the prevalence, virulence factors, and antibiotic and heavy metal resistance profiles of V. parahaemolyticus in Pacific mackerel (Pneumatophorus japonicus) from different markets in Zhejiang Province, People's Republic of China. In total, 112 (31.11%) V. parahaemolyticus isolates were identified from 360 Pacific mackerel samples, with an extremely low occurrence of the virulence genes trh (1.79%, 2 of 112) and tdh (0%, 0 of 112). Antibiotic resistance testing revealed that most isolates showed resistance to ampicillin (96.43%, 108 of 112) and streptomycin (90.18%, 101 of 112), whereas all strains were sensitive to kanamycin, florfenicol, cefamandole, and trimethoprim-sulfamethoxazole. Furthermore, 46.43% (52 of 112) of isolates, which had 12 different phenotypes, were classified as multidrug resistant. In addition, the multiple antibiotic resistance index values of isolates were between 0.05 and 0.63, and the maximum multiple antibiotic resistance index was attributed to two isolates that exhibited resistance to 12 antibiotics. Heavy metal resistance patterns were similar among the six different markets. The majority of isolates showed resistance to Cd2+ (78.57%) and Pb2+ (51.79%), and fewer were resistant to Cu2+ (37.50%), Zn2+ (25.00%), Co2+ (9.82%), Ni2+ (6.25%), and Mn2+ (4.46%). No isolates were resistant to Cr3+. In total, 22.32% (25 of 112) of strains were multiheavy metal resistant. Furthermore, multidrug resistance and multiheavy metal resistance were found to be positively correlated in the V. parahaemolyticus strains by using Pearson's correlation analysis (P = 0.008; R = 0.925). This information will contribute to the monitoring of variations in the antibiotic and heavy metal resistance profiles of V. parahaemolyticus strains from seafood and provide insight into the appropriate use of antibiotics and the safe consumption of seafood.

Detection of enterotoxin gene (sea) and biofilm formation ability among multidrug resistant Staphylococcus aureus isolated from shawarma sandwich sold at selected kiosks in Klang Valley, Malaysia

The occurrence of multi-drug resistant Staphylococcus aureus in food product of animal origin has increased the concern about their spread into the food supply chain. Presence of multidrug-resistant S. aureus in food products, including ready-to-eat foods imposes potential hazard for consumers. The objective of this research was to investigate the presence of multi-drug resistance of S. aureus in sixty ready-to-eat shawarma sandwiches. Agar-disc diffusion assay determined their resistance to 11 antibiotics. The sea and sed enterotoxin genes were detected by polymerase chain reaction method. Biofilm formation potential (BFP) was quantified by microtitre plate assay. The result revealed that thirty-six samples (60%) were positive for S. aureus. Majority of the isolates (n = 29; 80.6%) were resistant to at least one antibiotic. The isolates demonstrated highest resistance against ampicillin (69.4%) and penicillin (69.4%), while resistance to ciprofloxacin, tetracycline and kanamycin were 47.2%, 33.3% and 22.2%, respectively. Several isolates were resistant to trimethoprim (5.6%), trimethoprim-sulfamethoxazole- (2.8%), gentamicin (2.8%) and cephalothin (2.8%), while none exhibited resistance to chloramphenicol and nitrofurantoin. Out of the thirty-six isolates, twelve isolates (33.3%) were resistant to three or more classes of antibiotic (multidrug-resistant) and 50% had a Multiple Antibiotic Resistance index value more than 0.25. Of the multi-drug resistant isolates, four were positive for sea genes but no sed genes were present. All multi-drug resistance isolates were biofilm formers with five and six isolates were strong and moderate formers, respectively. Additionally, all the sea gene carrying multi-drug resistance isolates were strong biofilm formers. These findings revealed shawarma as a potential vehicle for the spread of multidrug-resistant S. aureus, suggesting more control measures for ready-to-eat food.

Incidence of antimicrobial resistance genes and class 1 integron gene cassettes in multidrug-resistant motile Aeromonas sp. isolated from ornamental guppy (Poecilia reticulata).

Aeromonas sp. are opportunistic pathogenic bacteria which are associated with various diseases in ornamental fish, aquaculture raised species and wild fisheries. In our study, antimicrobial resistance patterns, antimicrobial resistance genes and class 1 integron gene cassettes of 52 guppy-borne Aeromonas sp. were examined. The isolates were identified as A. veronii (n=34), A. dhakensis (n=10), A. hydrophila (n=3), A. caviae (n=3) and A. enteropelogenes (n=2) by gyrB gene sequencing. Every isolate was resistant to at least four antimicrobials in disc diffusion test. The resistance to amoxicillin, nalidixic acid and oxytetracycline was 100% among the tested isolates. 92·30, 76·92, 71·15, 51·92, 51·92 and 50·00% of the isolates were resistant to ampicillin, rifampicin, imipenem, cephalothin, tetracycline and trimethoprim respectively. The multiple antibiotic resistance index values ranged from 0·28 to 0·67. PCR amplification of antimicrobial resistance genes implied the occurrence of tetracycline resistance (tetA (65·39%), tetE (25·00%) and tetB (15·38%)), plasmid-mediated quinolone resistance (qnrS (26·92%) and qnrB (17·31%)) and aminoglycoside resistance (aphaAI-IAB (7·69%) and aac (6')-Ib (3·84%)) genes in the isolates. The IntI gene was positive for 36·54% of the isolates and four class 1 integron gene cassette profiles (aadA2, qacE2-orfD, aadA2-catB2 and dfrA12-aadA2) were identified. These data suggest that ornamental guppy can be a reservoir of multidrug-resistant Aeromonas sp. which comprise different antimicrobial resistance genes and class 1 integrons. SIGNIFICANCE AND IMPACT OF THE STUDY: Antimicrobial resistance genes and integron gene cassettes of ornamental fish-borne aeromonads are poorly studied. The antimicrobial resistance patterns, antimicrobial resistance genes and class 1 integron gene cassettes of Aeromonas sp. isolated from ornamental guppy were characterized for the first time in Korea. The incidence of different antimicrobial resistance genes and class 1 integron gene cassettes were observed in multidrug-resistant Aeromonas isolates. This result suggests that better management practices are necessary to prevent and address the serious consequences of indiscriminate and inappropriate antimicrobial use, and the distribution of multidrug-resistant bacteria.

Escherichia coli as Possible Agents of Spread of Multidrug Resistance in Port Harcourt, Rivers State.

Abstract Multidrug resistance (MDR) continues to be a growing global issue. The problem of MDR is fuelled in part by the spread of the genes encoding resistance horizontally which is linked particularly to conjugation involving plasmids. Studies have demonstrated the presence of plasmids in drug resistant isolates, few have shown a link between these plasmids and drug resistance via plasmid curing especially in our locale. This study set out to explore this link in Escherichia coli isolates from Port Harcourt, Nigeria. Plasmid curing was done on a selection of clinical and non-clinical bacteria using acridine orange and antibiotic susceptibility testing carried out on both cured and uncured variants. Data generated was analysed to ascertain the multiple antibiotic resistance (MAR) index and MDR of each isolate. Data was then compared to ascertain effects of plasmid curing on antibiotic resistance of the isolates. Results revealed a decrease in resistance to 7 of 8 antibiotics following plasmid curing. The highest change was noted in ceftazidime (40%), followed by ofloxacin (26.7%). Plasmid curing caused a shift in MAR index values of isolates from higher to lower indices. At MAR index values of ≤0.25 occurrence increased from 5% to 36.7% while at MAR index values ≥0.75, occurrence reduced from 29.9% to 10.0%. A reduction in the degree of MDR was noted (from 55% to 36.7%). Strikingly, the reduction in MDR level of non-clinical isolates was 30% as opposed to 3.4% in the clinical isolates. This study shows a link between plasmids and antibiotic resistance. For the non-clinical isolates, the high-level link between MDR and plasmid carriage could indicate a higher use of antimicrobials in non-clinical rather than clinical settings. Additionally, it could be an indicator for a higher risk of the transfer of MDR determinants from non-clinical sources to human populations in our locale.

Genotyping and Molecular Characterization of Extended-Spectrum Beta-Lactamases-Producing Uropathogenic Escherichia Coli in and Around Coimbatore District, Tamil Nadu, India

Background: Escherichia coli, an extraintestinal flora, develops virulence traits through a persistent encounter with host and constant exposure to antibiotics, which makes it line up as the most common urinary pathogen. Thus, this study aimed to screen the presence of virulence traits among multidrug-resistant urinary pathogenic E. coli among the urine samples collected from inpatients and outpatients of the multispecialty hospitals. Materials and Methods: Standard microbiological laboratory protocols were followed, and about 210 samples were processed and screened. Results: Among those samples, 114 were reported positive for the presence of uropathogenic E. coli(UPEC). Gender-wise distribution was found to be more among female patients (56%) than male patients (51%). During screening for hemolytic activity, 37% of test isolates were α hemolytic, 48% were β hemolytic, and 15% were γ hemolytic. Screening virulence among test isolates, sfa gene (49%), afa (42%), hly (68%), CNF (43%), and aer, accounts for 65%. Further, the multidrug resistance of the isolates was done by using ten antibiotics. All the isolates exhibited the multiple antibiotic resistance (MAR), and the highest percentage of resistance was found against ceftazidime (100%), and the least percentage of resistance was observed against imipenem (2%) followed by amikacin (8%). MAR index values of all the isolates ranged from 0.4 to 1. Conclusion: The presence of various virulence genes and the high degree of resistance among the isolates against the antibiotics used in this study confirm the prevalence of extended-spectrum β-lactamase producers among the UPEC.