Presence Of Antimicrobial-resistant Bacteria Research Articles

Presence of Antimicrobial-Resistant Bacteria and Resistance Genes in Soil Exposed to Wastewater Treatment Plant Effluent

Presence of Antimicrobial-Resistant Bacteria and Resistance Genes in Soil Exposed to Wastewater Treatment Plant Effluent

Determination of the amino linkage of the D-Dab residue of the cyclic lipo-octapeptide occidiofungins A-D and the antifungal activity of their analogues.

Recently, the demand for new antifungal drugs has increased due to the presence of antimicrobial resistant bacteria and their side effects. Occidiofungins (Ocfs) are cyclic lipo-octapeptides that possess unusual amino acids and potent antifungal activities. However, the chemical structure of the 2,4-diamino butyric acid (Dab) residue in the backbone of Ocfs has not been clarified thus far. Therefore, we conducted a structural analysis of the tripeptides around the Dab residue in Ocfs using 1H-NMR spectroscopy. We determined that the D-Dab residue in the peptide backbone of Ocfs has an α-amino linkage. Additionally, we found that Ocf A (5) and Bk-1119 have the same chemical structure. Moreover, the analogue possessing D-αDab (13) showed potent antifungal activity against A. oryzae.

Fresh produce as a reservoir of antimicrobial resistance genes: A case study of Switzerland

Antimicrobial resistance (AMR) can be transferred to humans through food and fresh produce can be an ideal vector as it is often consumed raw or minimally processed. The production environment of fresh produce and the agricultural practices and regulations can vary substantially worldwide, and consequently, the contamination sources of AMR. In this study, 75 imported and 75 non-imported fresh produce samples purchased from Swiss retailers were tested for the presence of antimicrobial resistant bacteria (ARB) and antimicrobial resistance genes (ARGs). Moreover, the plasmidome of 4 selected samples was sequenced to have an insight on the diversity of mobile resistome. In total, 91 ARB were isolated from fresh produce, mainly cephalosporin-resistant Enterobacterales (n = 64) and carbapenem-resistant P. aeruginosa (n = 13). All P. aeruginosa, as well as 16 Enterobacterales' isolates were multidrug-resistant. No differences between imported and Swiss fresh produce were found regarding the number of ARB. In 95 % of samples at least one ARG was detected, being the most frequent sul1, blaTEM, and ermB. Abundance of sul1 and intI1 correlated strongly with the total amount of ARGs, suggesting they could be good indicators for AMR in fresh produce. Furthermore, sul1 correlated with the fecal marker yccT, indicating that fecal contamination could be one of the sources of AMR. The gene sulI was significantly higher in most imported samples, suggesting higher anthropogenic contamination in the food production chain of imported produce. The analyses of the plasmidome of coriander and carrot samples revealed the presence of several ARGs as well as genes conferring resistance to antiseptics and disinfectants in mobile genetic elements. Overall, this study demonstrated that fresh produce contributes to the dissemination of ARGs and ARB.

Carbapenemase-Producing Bacteria Isolated from ICU Patients of a Peruvian Government Hospital during the COVID-19 Pandemic: A Descriptive Analysis.

Background and Objectives: In Peru, the presence of antimicrobial-resistant bacteria is a constant concern in hospitals and has likely increased in frequency during the pandemic. The objective of the study was to analyze the frequency of carbapenemase-producing bacteria resistant to two carbapenems (Imipenem and Meropenem), which were isolated from Peruvian patients in the intensive care unit of the Victor Lazarte Echegaray Hospital in Trujillo (Peru) during the COVID-19 pandemic. Materials and Methods: The biological samples of the patients hospitalized in the ICU were processed in the Microbiology Diagnostic Laboratory of the Víctor Lazarte Echegaray Hospital between May 2021 and March 2022. Antimicrobial sensitivity was determined with the automated system AutoScan-4, and for the identification of the type of carbapenemase, the RESISIT-3 O.K.N K-SET cassettes were used. Results: The results show that 76 cultures (76/129) had resistance to the two carbapenems (imipenem or meropenem), where the most frequent were Klebsiella pneuomoniae (31.6%), Pseudomonas aeruginosa (26.3%), and Acinetobacter baumannii (14.5%). Pseudomonas aeruginosa cultures showed at least three carbapenemase types (KPC, NDM, and OXA-48), while A. baumannii, Escherichia coli, and Burkholderia cepacia complex presented at least two carbapenemases (NDM and OXA-48). The carbapenemase NDM was detected in Enterobacter cloacae, Morganella morganii, and Proteus mirabilis, while KPC was present in all Klebsiella pneumoniae and Klebsiella oxytoca cultures. Conclusions: The samples from patients hospitalized in the Victor Lazarte Echegaray Hospital ICU showed a high prevalence of imipenem- and meropenem-resistant bacteria. These findings are relevant and concerning from the perspective of antibiotic-resistant bacteria monitoring, control, and disinfection. Thus, an appropriate antibiotic policy must be implemented.

First reported detection of the mobile colistin resistance genes, mcr-8 and mcr-9, in the Irish environment

The emergence and dissemination of mobile colistin resistance (mcr) genes across the globe poses a significant threat to public health, as colistin remains one of the last line treatment options for multi-drug resistant infections. Environmental samples (157 water and 157 wastewater) were collected in Ireland between 2018 and 2020. Samples collected were assessed for the presence of antimicrobial resistant bacteria using Brilliance ESBL, Brilliance CRE, mSuperCARBA and McConkey agar containing a ciprofloxacin disc. All water and integrated constructed wetland influent and effluent samples were filtered and enriched in buffered peptone water prior to culture, while wastewater samples were cultured directly. Isolates collected were identified via MALDI-TOF, were tested for susceptibility to 16 antimicrobials, including colistin, and subsequently underwent whole genome sequencing. Overall, eight mcr positive Enterobacterales (one mcr-8 and seven mcr-9) were recovered from six samples (freshwater (n = 2), healthcare facility wastewater (n = 2), wastewater treatment plant influent (n = 1) and integrated constructed wetland influent (piggery farm waste) (n = 1)). While the mcr-8 positive K. pneumoniae displayed resistance to colistin, all seven mcr-9 harbouring Enterobacterales remained susceptible. All isolates demonstrated multi-drug resistance and through whole genome sequencing analysis, were found to harbour a wide variety of antimicrobial resistance genes i.e., 30 ± 4.1 (10–61), including the carbapenemases, blaOXA-48 (n = 2) and blaNDM-1 (n = 1), which were harboured by three of the isolates. The mcr genes were located on IncHI2, IncFIIK and IncI1-like plasmids. The findings of this study highlight potential sources and reservoirs of mcr genes in the environment and illustrate the need for further research to gain a better understanding of the role the environment plays in the persistence and dissemination of antimicrobial resistance.

Multiple antimicrobial resistance in Enterobacteriaceae isolated from a Sea Lion (Otaria flavescens) specimen from Isla de Lobos, Uruguay: a case report

The rise of antimicrobial resistance is a growing concern worldwide, however the role that wildlife plays as a reservoir for antimicrobial resistant bacteria and the effect antimicrobial resistance has on them remain relatively unknown. We isolated and identified pathogenic bacteria from samples obtained from a juvenile sea lion (Otaria flavescens) necropsy from Isla de Lobos, Uruguay and tested the Enterobacterial strains for the presence of antimicrobial resistance. Swabs were taken from the larynx, esophagus, trachea, duodenum, and bladder. From a total of five isolated Gram-negative strains, three bacterial species were identified: Escherichia coli, Escherichia ferrusoni and Proteus mirabilis. All isolates expressed a resistance phenotype to Amoxicillin/clavulamic, Sulfa-trimethoprim, Tetracycline, Doxycycline and Streptomycin, while three of the five isolates showed resistance against Ciprofloxacin and two against Enrofloxacin and Cefovecin. These results provide relevant information on the presence of antimicrobial resistant bacteria in marine mammals in Uruguay, demonstrating the need to deepen scientific knowledge of the dynamics of antimicrobial resistance.

Analysis of Antimicrobial Use and the Presence of Antimicrobial-Resistant Bacteria on Austrian Dairy Farms-A Pilot Study.

The assumed link between high levels of antimicrobial use on farms and selection for antimicrobial-resistant (AMR) bacteria on that farm remains difficult to prove. In the pilot study presented here, we analysed total antimicrobial use on 50 dairy farms in Austria and also collected environmental samples to ascertain whether specific AMR bacteria were present. Antimicrobial use (AMU) analysis was based on electronic veterinary treatment records over a one-year period. Faecal samples for the assessment of extended-spectrum beta-lactamase (ESBL)-producing E. coli were collected from cowsheds, calf pens, and youngstock housing areas, as well as dust samples from barns, to isolate methicillin-resistant Staphylococcus aureus (MRSA). Bacteriological cultures were carried out on selective agar. Farms were split into groups of 25 of the highest antimicrobial users and 25 of the lowest users. Overall, samples from 13/50 (26.0%) farms were found to be positive for the presence of ESBL-producing E. coli. Of these, eight farms were in the low user group and five were in the high user group. Only one farm was confirmed to harbour MRSA. Statistical analyses demonstrated that there was no significant difference in this study population between high or low antimicrobial use with respect to the presence of ESBL-producing E. coli on farms (p = 0.33). In conclusion, the presence of specific AMR bacteria on farms in this study population was not found to have a statistically proven relationship with their level of antimicrobial use.

Comparison of Organic and Conventional Food and Food Production

Comparison of Organic and Conventional Food and Food Production

Plasmid-associated antimicrobial resistance and virulence genes in Escherichia coli in a high arctic reindeer subspecies

In extreme environments, such as the Arctic region, the anthropogenic influence is low and the presence of antimicrobial-resistant bacteria is unexpected. In this study, we screened wild reindeer (Rangifer tarandus platyrhynchus) from the Svalbard High Arctic Archipelago for antimicrobial-resistant Escherichia coli and performed in-depth strain characterisation. Using selective culturing of faecal samples from 55 animals, resistant E. coli were isolated and subjected to minimum inhibitory concentration (MIC) determination, conjugation experiments and whole-genome sequencing. Twelve animals carried antimicrobial-resistant E. coli. Genomic analysis showed IncF plasmids as vectors both for resistance and virulence genes in most strains. Plasmid-associated genes encoding resistance to ampicillin, sulfonamides, streptomycin and trimethoprim were found in addition to virulence genes typical for colicin V (ColV)-producing plasmids. Comparison with previously reported IncF ColV plasmids from human and animal hosts showed high genetic similarity. The plasmids were detected in E. coli sequence types (STs) previously described as hosts for such plasmids, such as ST58, ST88 and ST131. Antimicrobial-resistant E. coli were detected from Svalbard reindeer. Our findings show that successful hybrid antimicrobial resistance-ColV plasmids and their host strains are widely distributed also occurring in extreme environmental niches such as arctic ecosystems. Possible introduction routes of resistant bacterial strains and plasmids into Svalbard ecosystems may be through migrating birds, marine fish or mammals, arctic fox (Vulpes lagopus) or via human anthropogenic activities such as tourism.

A Comparative Quantitative Assessment of Human Exposure to Various Antimicrobial-Resistant Bacteria among U.S. Ground Beef Consumers

Consumption of animal-derived meat products is suspected as an important exposure route to antimicrobial resistance, as the presence of antimicrobial-resistant bacteria (ARB) along the beef supply chain is well documented. A retail-to-fork quantitative exposure assessment was established to compare consumers' exposure to various ARB due to the consumption of ground beef with and without "raised without antibiotics" claims and to inform potential exposure mitigation strategies related to consumer practices. The microbial agents evaluated included Escherichia coli, tetracycline-resistant (TETr) E. coli, third-generation cephalosporin-resistant E. coli,Salmonella enterica, TETrS. enterica, third-generation cephalosporin-resistant S. enterica, nalidixic acid-resistant S. enterica, Enterococcus spp., TETrEnterococcus spp., erythromycin-resistant Enterococcus spp., Staphylococcus aureus, and methicillin-resistant S. aureus. The final model outputs were the probability of exposure to at least 0 to 6 log CFU microorganisms per serving of ground beef at the time of consumption. It was estimated that tetracycline resistance was more prevalent in ground beef compared with other types of resistance, among which the predicted average probability of ingesting TETrEnterococcus was highest (6.2% of ingesting at least 0 log CFU per serving), followed by TETrE. coli (3.1%) and TETrSalmonella (0.0001%), given common product purchase preferences and preparation behaviors among beef consumers in the United States. The effectiveness of consumer-related interventions was estimated by simulating the differences in exposure as a result of changes in consumer practices in purchasing, handling, and preparing ground beef. The results indicated that proper use of recommended safe cooking and food preparation practices mitigates ARB exposure more effectively than choosing raised without antibiotics compared with conventional beef.

Antimicrobial Resistance Levels among Gram-negative Bacteria from Peruvian Boobies (Sula variegata) in Northern Peru.

The presence of antimicrobial-resistant bacteria in feces of 42 Peruvian Boobies (Sula variegata) from a Northern Peru island was evaluated using MicroScan and disk diffusion. Fourteen microorganisms were recovered, including three Pseudomonas spp. resistant to one antibiotic each, and four multiresistant Escherichia coli. Antimicrobial-resistant bacteria are reported in S. variegata.

Potential Transfer of Antimicrobial Resistance and Zoonotic Bacteria Through Global Ornamental Fish Trade

There is an impressive global trade in live tropical freshwater ornamental fish. These consignments may contain potentiallyharmful bacteria and contaminants of therapeutics, a potential public health risk when professionals have direct contact with fish and transport water. In 2014–2015 we sampled and tested fifty consignments from 13 countries outside Europe at arrival in the Netherlands. Potential zoonotic bacteria were detected in 11 of 50 ornamental fish consignments. Aeromonasspp. (n = 59) isolated from fish showed resistance to oxytetracycline (85 % of strains), flumequine (53 %), trimethoprim-sulphamethoxazole (30 %), neomycin (34 %), florfenicol (9 %), and to nitrofurantoin (17 %). Isolates from fish consignments from Singapore and Congo showed multi-resistance against various antibiotics. In total 11 Escherichia coliisolates suspected of ESBL (extended-spectrum beta-lactamase)-production were found in 2 of 50 freshwater ornamental fish and 9 of 50 transport water samples, from Singapore (4×), Indonesia (2×), Congo (2×), Thailand (1×), and Hong Kong Special Administrative Region ofthe People's Republic of China (HKSAR) (1×). OXA-48-like carbapenemase gene variants of limited public health riskwere frequently found in Shewanella spp. Forty-nine of fifty water samples contained residues of one or more antibiotics, mostly tetracyclines and fluoroquinolones, but also chloramphenicol and nitrofurans, and of malachite green. Our findings are of concern since the current EU border inspections for import control do not consider these human health risks. It is therefore recommended to regularly screen consignments from more countries for the presence of antimicrobial resistant bacteria, residues of antibiotics, and potential zoonotic bacteria.

Phenotypic and Genotypic Antimicrobial Resistance in Non-O157 Shiga Toxin-Producing Escherichia coli Isolated From Cattle and Swine in Chile.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen that causes bloody diarrhea and hemolytic-uremic syndrome in humans, and a major cause of foodborne disease. Despite antibiotic treatment of STEC infections in humans is not recommended, the presence of antimicrobial-resistant bacteria in animals and food constitutes a risk to public health, as the pool of genes from which pathogenic bacteria can acquire antibiotic resistance has increased. Additionally, in Chile there is no information on the antimicrobial resistance of this pathogen in livestock. Thus, the aim of this study was to characterize the phenotypic and genotypic antimicrobial resistance of STEC strains isolated from cattle and swine in the Metropolitan region, Chile, to contribute relevant data to antimicrobial resistance surveillance programs at national and international level. We assessed the minimal inhibitory concentration of 18 antimicrobials, and the distribution of 12 antimicrobial resistance genes and class 1 and 2 integrons in 54 STEC strains. All strains were phenotypically resistant to at least one antimicrobial drug, with a 100% of resistance to cefalexin, followed by colistin (81.5%), chloramphenicol (14.8%), ampicillin and enrofloxacin (5.6% each), doxycycline (3.7%), and cefovecin (1.9%). Most detected antibiotic resistance genes were dfrA1 and tetA (100%), followed by tetB (94.4%), blaTEM−1 (90.7%), aac(6)-Ib (88.9%), blaAmpC (81.5%), cat1 (61.1%), and aac(3)-IIa (11.1%). Integrons were detected only in strains of swine origin. Therefore, this study provides further evidence that non-O157 STEC strains present in livestock in the Metropolitan region of Chile exhibit phenotypic and genotypic resistance against antimicrobials that are critical for human and veterinary medicine, representing a major threat for public health. Additionally, these strains could have a competitive advantage in the presence of antimicrobial selective pressure, leading to an increase in food contamination. This study highlights the need for coordinated local and global actions regarding the use of antimicrobials in animal food production.

Fecal cultivable aerobic microbiota of dairy cows and calves acting as reservoir of clinically relevant antimicrobial resistance genes.

Antimicrobial resistance has become a global threat to public health since multidrug-resistant (MDR) bacteria have been reported worldwide carrying different antimicrobial resistance genes (ARGs), and animals have been described as a reservoir of ARGs. The presence of antimicrobial-resistant bacteria and ARGs in the food matrix is a risk to public health. This study aimed to research the presence of clinically relevant ARGs for important antimicrobials and genetic elements in fecal samples from dairy cows and calves on a Brazilian farm. In this study, a total of 21 fecal samples were collected, and then, the DNA of cultivable aerobic bacteria was extracted. Fifty-seven ARGs and twenty-three genetic elements were researched by PCR and confirmed by sequencing. Several ARGs that confer resistance to β-lactams, tetracyclines, fluoroquinolones, sulphonamides, phenicols, aminoglycoside, glycopeptides, and macrolides were detected. A total of 200 amplicons from 23 ARGs (blaCTX-M-Gp2, blaCMY, blaSHV, tetA, tetB, tetC, qepA, qnrB, qnrS, oqxA, oqxB, vanC1, vanC2/3, aadA, sul1, sul2, sul3, ermB, mefAE, floR, cmlA, aadA, aph(3')-Ia, aac(3')-Ia), and 145 amplicons from 12 genetic elements (IncF, IncFIA, IncFIB, IncI1, IncY, IncU, IncK, IncP, IncR, IncHI1, ColE-like, intI1) were detected. The results presented in this study call attention to the monitoring of antimicrobial resistance in dairy farms worldwide. MDR bacteria and ARGs can spread to different sources, including milk products, which are one of the most consumed products worldwide, representing a potential risk to human health.

Qualidade microbiológica e caracterização da resistência antimicrobiana de bactérias isoladas de queijos Coalho comercializados em Vitória da Conquista-Bahia

Neste estudo foram determinadas a qualidade higiênico-sanitária, a prevalência e a resistência antimicrobiana de patógenos isolados de 24 amostras de queijo Coalho comercializados em duas feiras livres do município de Vitória da Conquista, Bahia. Foram realizadas análises físico-químicas e microbiológicas através de métodos convencionais interpretados conforme legislação vigente. Identificamos que 75% das amostras eram comercializadas em temperatura inadequada e que 100% apresentaram contagem para coliformes totais acima do limite aceitável. Staphylococcus coagulase positiva e Escherichia coli foram isolados em 87,5% e 62,5% das amostras, respectivamente. Não foi detectada a presença de Listeria monocytogenes e Salmonella sp. Identificamos 51,1% de resistência a pelo menos um dos sete antimicrobianos testados para Staphylococcus coagulase positiva e 44,4% para pelo menos um dos 11 avaliados para E.coli. As análises realizadas evidenciaram uma precariedade higiênico-sanitária na produção e comercialização de queijo coalho nas feiras livres de Vitória da Conquista. Torna-se também uma preocupação, a presença de bactérias resistentes aos antimicrobianos nestes queijos. Deste modo, ressaltamos a importância do controle de qualidade na produção e comercialização destes produtos, assim como a necessidade das ações da vigilância sanitária para orientação aos manipuladores e produtores de queijo.

Wastewater as a Probable Environmental Reservoir of Extended-Spectrum-β-Lactamase Genes: Detection of Chimeric β-Lactamases CTX-M-64 and CTX-M-123.

The presence of antimicrobial-resistant bacteria and resistance genes in aquatic environments is a serious public health concern. This study focused on Escherichia coli possessing blaCTX-M genes in wastewater inflows. Twelve crude inflow water samples from wastewater treatment plant (WWTP) A and two samples each from three other WWTPs were collected in 2017 and 2018. A total of 73 E. coli isolates with 31 different sequence types (STs) harboring distinctive blaCTX-M gene repertoires were detected. In WWTP A influents, blaCTX-M-14 (14 isolates) was dominant, followed by blaCTX-M-15 (12 isolates) and blaCTX-M-27 (10 isolates). The chimeric blaCTX-M-64 and blaCTX-M-123 genes were each identified in one of the E. coli isolates from the same WWTP A inflow port. The blaCTX-M-27 gene was associated with five of seven B2-ST131 isolates, including three isolates of the B2-O25b-ST131-H30R/non-Rx lineage. One of the remaining two isolates belonged to the B2-O25b-ST131-H30R/Rx lineage harboring the blaCTX-M-15 gene. As for the B2-O25b-ST131-H30R/non-Rx lineage, two isolates with blaCTX-M-27 were recovered from each of the WWTP B and D influents, and one isolate with blaCTX-M-174 was also recovered from WWTP B influent. Whole-genome sequencing of chimeric blaCTX-M-harboring E. coli isolates revealed that the blaCTX-M-64 gene was integrated into the chromosome of ST10 E. coli B22 via ISEcp1-mediated transposition of a 9,467-bp sequence. The blaCTX-M-123-carrying IncI1 plasmid pB64 was 109,169 bp in length with pST108. The overall findings suggest that wastewater may act as a probable reservoir of clinically significant clonal lineages mediating antimicrobial resistance genes and chimeric genes that have not yet been identified from human isolates of domestic origin in Japan.IMPORTANCE Global spread of CTX-M-type extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is a critical concern in both clinical and community settings. This dominance of CTX-M-type ESBL producers may be largely due to the successful international spread of epidemic clones, as represented by the extraintestinal pathogenic Escherichia coli (ExPEC) ST131. Our findings highlight the worrisome presence of diverse E. coli clones associated with humans, including ExPEC lineages harboring the most common blaCTX-M variants in untreated wastewater samples. Moreover, the chimeric genes blaCTX-M-64 and blaCTX-M-123, which have not yet been identified from human isolates of domestic origin in Japan, were identified. Exposure to untreated wastewater through combined sewer overflow caused by heavy rains derived from abnormal weather change could pose a risk for human health due to ingesting those antimicrobial-resistant bacteria.

Book Review: Soil Pollution: A Hidden Danger Beneath our Feet

Book Review: Soil Pollution: A Hidden Danger Beneath our Feet

Clonal spread of antimicrobial-resistant Escherichia coli isolates among pups in two kennels

Although the dog breeding industry is common in many countries, the presence of antimicrobial resistant bacteria among pups in kennels has been infrequently investigated. This study was conducted to better understand the epidemiology of antimicrobial-resistant Escherichia coli isolates from kennel pups not treated with antimicrobials. We investigated susceptibilities to 11 antimicrobials, and prevalence of extended-spectrum β-lactamase (ESBL) in 86 faecal E. coli isolates from 43 pups in two kennels. Genetic relatedness among all isolates was assessed using pulsed-field gel electrophoresis (PFGE). Susceptibility tests revealed that 76% of the isolates were resistant to one or more of tested antimicrobials, with resistance to dihydrostreptomycin most frequently encountered (66.3%) followed by ampicillin (60.5%), trimethoprim-sulfamethoxazole (41.9%), oxytetracycline (26.7%), and chloramphenicol (26.7%). Multidrug resistance, defined as resistance against two or more classes of antimicrobials, was observed in 52 (60.5%) isolates. Three pups in one kennel harboured SHV-12 ESBL-producing isolates. A comparison between the two kennels showed that frequencies of resistance against seven antimicrobials and the variation in resistant phenotypes differed significantly. Analysis by PFGE revealed that clone sharing rates among pups of the same litters were not significantly different in both kennels (64.0% vs. 88.9%), whereas the rates among pups from different litters were significantly different between the two kennels (72.0% vs. 33.3%, P < 0.05). The pups in the two kennels had antimicrobial-resistant E. coli clones, including multidrug-resistant and ESBL-producing clones. It is likely that resistant and susceptible bacteria can clonally spread among the same and/or different litters thus affecting the resistance prevalence.

Ants as carriers of antibiotic-resistant bacteria in hospitals

The presence of antimicrobial-resistant bacteria and carried by ants isolated from hospitals was investigated in Campos dos Goytacazes, RJ, Brazil. Three health institutions were visited from 2001 to 2002 and samples were collected within critical areas of medical care based on criteria of greater risk of patient hospital acquired-infection. Four ant species were identified, Tapinoma melanocephalum (Fabricius)(63.1%), Paratrechina longicornis (Latreille)(21.1%), Monomorium pharaonis (L.)(10.5%), and Solenopsis saevissima (S. Smith)(5.3%) carrying 21 species of bacteria. The tests for bacteria species identification and antimicrobial-resistance profile were carried out by using standardized kits and evaluated by automated equipment. Among the bacteria isolates, some were considered multiresistant isolates, including genera Acinetobacter, Streptococcus, Gemella, and Klebsiella. For Enterobacter antibacterial analysis the disk diffusion standard method was used. The results suggest that there are risks for patients which seek for health assistance in the hospitals studied, and the presence of emerging bacteria isolates in hospital carried by ants must be considered.

Effect of Metaphylactic Antimicrobial Use on the Development of Antimicrobial Resistance in Fecal E. coli Isolates of Feedlot Cattle

Much of the long-term economic and environmental stability of beef production seems to be driven by marketplace issues such as food safety and quality assurance that would include the potential presence of antimicrobial resistant bacteria. Long-acting injectable antimicrobials are widely used for metaphylaxis in calves on arrival at the feedlot. Previous feedlot trials by other researchers have associated metaphylaxis with lowered rates of morbidity and mortality from respiratory disease. Average daily gain, feed efficiency, case fatality rates, treatment rates, and relapse rates for bovine respiratory disease have also improved in animals where metaphylaxis is used. Metaphylaxis, therefore, has great industry significance from both an economic and animal welfare perspective. The objectives of this study were: 1) to determine the prevalence of fecal E. coli resistant to antimicrobials in auction-mart derived weaned calves, 2) to determine the effect of metaphylactic antimicrobial usage on the development of fecal E. coli resistant to various antimicrobials, and 3) to determine the persistence of antimicrobial resistant fecal E. coli and to evaluate the potential risk of their presence preslaughter.