Frequent Resistance Patterns Research Articles

Multiple antibiotic resistance of Salmonella Infantis in the Peruvian poultry production chain: Detection in birds, the farming environment, and chicken carcasses

Poultry can act as a reservoir of Salmonella enterica serotype Infantis (S. Infantis) of clinical and epidemiological importance because it triggers foodborne disease outbreaks and presents antibiotic multiresistance. The present study aimed to determine antimicrobial resistance in S. Infantis isolates from poultry livers, litter and chicken carcasses from Lima, Peru, during 2022–2023. S. Infantis was isolated from 10.1 % (27/267), 4.7 % (4/86), and 8 % (2/25) of the bird, litter and carcass samples, respectively. All isolates showed resistance to nalidixic acid (NA). In addition, 94 %, 76 %, 70 %, 48 %, and 45 % of the isolates showed resistance to tetracycline (TET), amoxicillin (AMX), chloramphenicol (C), gentamicin (GEN) and trimethoprim/sulfamethoxazole (TS), respectively. All isolates showed susceptibility to imipinem and amoxicillin/clavulanic acid. Of the isolates, 93.9 % displayed multidrug resistance. The most frequent resistance pattern was C-AMX-NA-GEN-TET (24.2 %, n=8), determined even from carcass isolates, followed by C-AMX-NA-TET (18.2 %, n=6), and C-AMX-NA-GEN-TS-TET (12.1 %, n=4). The presence of these multidrug-resistant S. Infantis isolates is a threat to food safety and public health.

Clinical and Microbiological Characterization of Pediatric Patients with Urinary Tract Infection in a Fourth-Level Hospital in Bogotá, Colombia, over a Period of Four Years

Introduction: Urinary tract infection is one of the most frequent infectious diseases in the pediatric population. There is no updated data available in literature of the pathogens responsible for complicated and uncomplicated UTI in children and their antimicrobial resistance profiles at the San Ignacio University Hospital or in the city of Bogotá. Objective: Carry out a demographic and clinical characterization of pediatric patients with UTI and a microbiological characterization of the resistance pattern of its main etiological agents. Study design: Cross-sectional study including all pediatric patients under 10 years of age with UTI confirmed by urine culture who consulted our institution between January 2014 and December 2017. Redcap was used for the registration of data corresponding to demographic variables, clinical manifestations, isolated microorganisms with their antibiograms, complications, and recurrence rate of UTI. Results: A registry of 675 patients under 10 years of age with urinary tract infection was obtained, with an average age of 23 months and a higher prevalence in females (71%). 15.4% of the patients had an urinary tract malformation, 3.5% had history of previous urological surgery and 21% had constipation as a comorbidity. 98.4% of the UTIs were acquired in the community and the most common isolated agents were Escherichia coli (73.9%), Proteus mirabilis (12.4%) and Klebsiella pneumoniae (4.7%). The most frequent resistance patterns were penicillinase-producing (41.5%) multi-sensitive (32.1%) and cephalosporins resistance (26%). Regarding the treatment established, cephalosporins were used in 92% of the cases; mainly of first generation (61%) and third generation (38%). 23% of the patients had an associated complication.

Comparative occurrence and antibiogram of extended-spectrum β-lactamase-producing Escherichia coli among post-weaned calves and lactating cows from smallholder dairy farms in a parallel animal husbandry area.

Background and Aim:Inappropriate overuse of antimicrobials might be associated with the spreading of antimicrobial-resistant bacteria in animal-based food products. Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli have been recognized as an emerging global problem in a One Health approach. This study aimed to assess the occurrence and antimicrobial-susceptible profiles of ESBL-producing E. coli among post-weaned calves and lactating cows in a parallel animal husbandry area.Materials and Methods:Seventy-two pool fecal samples were collected from 36 smallholder dairy farms registered in Ban Hong Dairy Cooperatives, Lamphun Province, Thailand. Pre-enriched fecal samples were cultured in MacConkey agar supplemented with cefotaxime. The potential E. coli isolates were identified by not only biochemical tests but also polymerase chain reaction assay of the 16S rRNA gene. ESBL production was confirmed by the combination disk test. Antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method.Results:The occurrence of ESBL-producing E. coli at the farm level was 80.56%. The different phenotypic antibiogram of ESBL-producing E. coli was observed among post-weaned calf and lactating cow specimens. The most frequent resistance patterns of ESBL-producing isolates from both groups were amoxicillin-ceftiofur-cephalexin-cephalothin-cloxacillin-streptomycin-oxytetracycline-sulfamethoxazole/trimethoprim. For the median zone diameter, enrofloxacin-resistant isolates with narrow zone diameter values from lactating cow specimens were particularly more than post-weaned calf specimens (p<0.05).Conclusion:These findings revealed the dynamic changes in ESBL-producing E. coli from calves and lactating cows in Lamphun Province, posing the inevitability to prevent bacterial transmission and optimize antimicrobial therapy in dairy farming.

Identification and Mapping of Cross-Resistance Patterns to ALS-Inhibitors in Greater Beggarticks (Bidens spp.)

ABSTRACT: Greater beggarticks (Bidens pilosa and Bidens subalternans) biotypes have been under selection pressure of ALS-inhibitors since early 90’s in Brazil. The objectives of this work were to investigate whether there are different cross-resistance patterns among ALS-inhibitors herbicides in Bidens spp. biotypes; to understand the geographic distribution of resistance patterns in grains producing regions in Brazil; and evaluate the possibility of multiple resistance to ALS-inhibitors, EPSPs inhibitor and photosystem II inhibitors. Dose-response experiments were carried out with imazethapyr, chlorimuron and diclosulam in three populations. Sensibility to others 34 populations both from Paraná State (PR) and from others Brazilian regions were also evaluated. The dose-response assay revealed cross-resistance with different patterns. One population was resistant to all three herbicides, the second population was tolerant to both imazethapyr and chlorimuron, but not to diclosulam, while a third population was resistant merely to imazethapyr. The results exhibited different cross-resistance patterns, since they can be found in other Bidens spp. populations. However, no relationship was observed between geographic areas where samples were collected and resistance patterns. Conclusively, the most frequent resistance pattern was R2 (resistance to imazethapyr, chlorimuron and diclosulam).

Comparison of annual and regional variation in multidrug resistance using various classification metrics for generic Escherichia coli isolated from chicken abattoir surveillance samples in Canada

Antimicrobial resistance (AMR) and related multidrug resistance (MDR) are important global public health issues. The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) conducts surveillance of AMR in enteric bacteria and monitors MDR. However, the analysis of MDR is complicated by the lack of consensus for MDR definitions. The objectives were to describe the most common resistance patterns in generic E. coli isolates from chicken cecal samples and determine the impact of using different MDR metrics for analysis of annual and regional variation in MDR. From 2006 to 2015, 1598 E. coli isolates were collected from chickens at slaughter for CIPARS. Three MDR classification metrics were used: MDR-drug (MDR if the isolate was resistant (R) to ≥3 of the 13 antimicrobials); MDR-cat (MDR if R to ≥3 of the 9 antimicrobials categories); and MDR-class (MDR if R to ≥3 of the 6 antimicrobial classes). The most frequent resistance patterns overall, and by year and region were extracted along with patterns that included resistance to quinolones, and third generation cephalosporins and/or β-lactams with β-lactamase inhibitors. For each MDR metric, mixed logistic regression models, which included random intercepts for abattoir, were fitted to analyze the association between prevalence of MDR, and year and region. Interaction effects between year and region were evaluated. Overall, and in all years and regions, non-resistant was the most common resistance pattern (24.9%, 95% CI 22.8–27.1%). Resistance patterns that included third generation cephalosporins and β-lactams with β-lactamase inhibitors were common. The prevalence of MDR was variable: MDR-class 38.5% (95% CI 36.1–41.0%); MDR-cat 49.4% (95% CI 46.9–51.9%); and MDR-drug 53.3% (95% CI 50.8–55.8%). Based on models fitted with individual fixed effects, significant annual variation in the prevalence of MDR was identified with MDR-drug and MDR-class models. Significant regional variation was identified for all three MDR metric models. Significant interaction effects between year and region were identified with the MDR-drug and MDR-cat multivariable mixed logistic regression models. The interpretation of the association between the prevalence of MDR, and year and region differed depending on the MDR metric used. These results are supportive of the previous concerns that caution must be taken when comparing MDR results between studies. Global consensus is needed for the optimal MDR classification metric for foodborne enteric bacteria AMR surveillance.

Detection of Genotipically Related Multi-resistant Escherichia coli Isolates in Pig Feces and Carcasses

Background: Antimicrobial resistant bacteria are considered a hazard not only for the treatment of animal diseases but also for public health. Commensal bacteria, such as Escherichia coli are considered a good indicator of antimicrobial resistance in the population, because it is a gut inhabitant and thus undergoes constant pressure of selection by the administration of antimicrobials. Regarding the public health, it is important to evaluate if resistant bacteria carried in the intestinal content of slaughter pigs can be found on the surface of pre chill carcasses. Therefore, the aims of this study were to evaluate the frequency of antimicrobial resistance in E. coli isolated from feces and pig carcasses; and to assess if multi-resistant isolates from both sources were phenotypically and genotypically related.Materials, Methods &amp; Results: Two sampling cycles were conducted in three pig slaughterhouses (A, B and C). In each cycle, samples were collected form: i. feces deposited on the pen floor of the lairage; ii. surface of carcasses at the prechill step. Samples were submitted to a protocol of isolation and confirmation of Escherichia coli. Isolates were grouped according to the origin: feces (n = 355); carcasses (n = 319); and evaluated for antimicrobial resistance by agar diffusion test. Ninety two isolates presenting multidrug resistance profile were analyzed by pulsed-field gel eletrophoresis (PFGE). Among the 674 isolates of E. coli, 7.4% were susceptible to all tested antibiotics while 79.5% (536/674) were multi-resistant. The most frequent resistance patterns were displayed to tetracycline (Tet, 85.9%), ampicillin (Amp, 73.0%), sulfonamide (Sul, 70.0%), florfenicol (Flo, 65.0%) and nalidixic acid (Nal, 58.9%). The most frequent multi-resistance profile among isolates from both origins was [AmpFloNalSulTet]. Multiresistant isolates originated from feces and carcasses displaying genotypically related pulsotypes (≥70% similarity) were found in all three slaughterhouses.Discussion: In agreement with other studies, E. coli isolated from pig feces and carcasses demonstrated a high frequency of antimicrobial resistance and multi-resistance. The most frequent resistance profiles included antimicrobials frequently used on farm as well as drugs that have been banned as feed additives some years ago in Brazil. The selection of resistant strains may be related to the selection pressiondue to the use of antimicrobials in the pig production chain as well as the co-selection of resistance mediated by genes located in common genetic elements. Therefore, the ban of an individual drug is not always associated with the immediate disappearance of the resistance phenotype in the bacteria population. The fact that most multi-resistant E. coli isolates from carcasses belonged to pulsotypes related to those originated from feces samples indicates that resistant E. coli isolates selected on farm may be able to survive the slaughter process and be found on the carcass. In this case, the possibility of those strains being able to reach the population through the consumption of pork products may have to be considered. This hazard has motivated the ban of antimicrobial use in animals in some countries. However, the ban of antimicrobials use on farm is a controversial issue, due to the economical losses that may result from this measure. Therefore, the prudent use of antimicrobials on farm should be encouraged and its influence in the multi-resistance profile of the enteric microbiota should be further studied.

MULTIDRUG RESISTANCE AND INTEGRONS IN ESCHERICHIA COLI ISOLATED FROM FOOD-PRODUCING ANIMALS IN SAUDI ARABIA

Transference of antimicrobial resistance gene determinants by integrons is one of the important factors that can contribute to the increase in multidrug-resistant bacteria. The present study aimed to investigate 56 strains of animal-derived E. coli strains obtained from fecal materials of slaughtered food animals for their resistance to commonly used antimicrobial agents for presence of integrons and detection of mercury reductase gene (MerA) as indicative for presence of transposons. Multidrug resistance (MDR) was found in 38 (68%) of the strains as indicated by disk diffusion method. The most frequent resistance patterns was to Ampicillin, Sulfonamides, Nalidixic acid, Cephalosporin's, Tetracycline, and Aamoxicillin/Clavulanic acid. None of tested strains were resistant to Cefepime or Imipenem. The polymerase chain reaction (PCR) results showed the presence of integrons in 26 (68.4%) of MDR strains tested as well as the mercury resistance gene in 12 (46.2%) of strains with integrons, indicating the role of Tn21 transposon in dissemination of the integrons and their gene cassettes within the samples studied. Our results showed high resistance rate of E. coli from food animals to routine antibiotics and indicate that integrons and transposon are common among MDR isolates of food producing isolates in Saudi Arabia.

Screening outcomes from patients with suspected multidrug-resistant tuberculosis: lessons learned in the Philippines

The high prevalence of multidrug-resistant tuberculosis (MDR-TB) in the Philippines is a challenge for the National TB Programme. To assess patterns of drug resistance and screening outcomes among MDR-TB suspects evaluated from 2003 to 2008 at DOTS-Plus clinics in the Philippines. Descriptive study of 4897 consecutive patients with suspected MDR-TB. The median time from the first visit until a diagnosis of drug-resistant TB was 132 days (IQR 110-166 days). Among patients screened for MDR-TB, the most frequent resistance pattern among those previously treated in DOTS facilities was resistance to isoniazid (INH) and rifampicin (RMP). Resistance to INH+RMP plus fluoroquinolones was the most common pattern among those who had failed Category II treatment and patients treated by non-DOTS facilities. Among patients with MDR-TB, 57% ultimately received appropriate treatment with second-line drugs. The remaining 43% were lost to follow-up (25%), died (14%) or refused treatment (4%). Resistance to INH+RMP is the most frequent resistance pattern among patients referred from DOTS clinics in the Philippines for suspected MDR-TB. Initial use of standard regimens based on national survey data and quick uptake of new rapid molecular resistance tests may be useful to reduce diagnostic delays and expedite treatment for drug-resistant TB.

Diversity of fecal coliforms and their antimicrobial resistance patterns in wastewater treatment model plant

The occurrence of resistance patterns among wastewater fecal coliforms was determined in the study. Susceptibility of the isolates was tested against 19 antimicrobial agents: aminoglycosides, aztreonam, carbapenems, cephalosporines, beta-lactam/beta-lactamase inhibitors, penicillines, tetracycline, trimethoprim/sulfamethoxazole, and fluoroquinolones. Additionally the removal of resistant isolates was evaluated in the laboratory-scale wastewater treatment model plant (M-WWTP), continuously supplied with the wastewater obtained from the full-scale WWTP. Number of fecal coliforms in raw (after mechanical treatment) and treated wastewater, as well as in aerobic chamber effluent was determined using selective medium. The selected strains were identified and examined for antibiotic resistance using Phoenix Automated Microbiology System (BD Biosciences, USA). The strains were identified as Escherichia coli (n=222), Klebsiella pneumoniae ssp. ozaenae (n=9), and Pantoea agglomerans (n=1). The isolate of P. agglomerans as well as 48% of E. coli isolates were sensitive to all antimicrobials tested. The most frequent resistance patterns were found for ampicillin: 100% of K. pneumoniae ssp. ozaenae and 41% of E. coli isolates. Among E. coli isolates 12% was regarded as multiple antimicrobial resistant (MAR). In the studied M-WWTP, the applied activated sludge processes reduced considerably the number of fecal coliforms, but increased the ratio of antimicrobial-resistant E. coli isolates to sensitive ones, especially among strains with MAR patterns.

Distribution of drug resistance among enterococci and Salmonella from poultry and cattle in Ethiopia

Enterococci and Salmonella were isolated from feces of chicken in intensive poultry farms and cattle which are maintained following traditional practices. Their resistance to different antibiotics was also determined. A total of 298 enterococcal isolates consisting of Enterococcus faecium (49.6%), Enterococcus durans (26.9%), Enterococcus hirea (11.9%), and Enterococcus faecalis (11.5%) were obtained. Among the enterococci, resistance to erythromycin (Ery), clindamicin (Cli), amoxicillin (Amo), ampicillin (Amp), and cephalothin (Cep) was high. Resistance to vancomycin (Van) was detected in all enterococcal species. Over 80% of the isolates showed multiple drug resistance. The most dominant patterns in poultry were Amo/Amp/Cep/Pen and Amo/Amp/Cep/Cli/Pen/Van. Among isolates from cattle, Amo/Amp/Cep/Cli/Ery/Pen/Van and Amo/Amp/Cli/Ery/Pen/Van constituted the most dominant multiple resistance patterns. A total of 51 Salmonella isolates were obtained from poultry (43/280) and cattle (8/450). About 70% of the isolates had varying resistance to the tested antibiotics. Multiple drug resistance was observed in over 30% of the Salmonella isolates. The most frequent resistance pattern was Amo/Amp/Cip/Gen/Str in cattle and Amo/Amp/Cep/Cip/Gen/Kan/Str in poultry. Enteroccoccal and Salmonella isolates showed multiple resistance to those antibiotics used in human and veterinary medicine. The high frequency of isolation of resistant enterococci is indicative of the wide dissemination of antibiotic resistant bacteria in the farm environment.

남해안 어류양식장에서 분리된 Escherichia coli에 대한 항균제 감수성

Three-hundred and sixteen Escherichia coli strains from seawater, and a variety of farmed fishes, including oliver flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major) and sea bass (Lateolabrax japonicus) between May to October in 2004, were tested by agar dilution method to determine their susceptibility patterns to 17 antimicrobial agents. Overall, 92.1% of Escherichia coli isolates from samples showed antimicrobial resistance to at least one antimicrobial agent and the multiple resistance was seen in 173 isolates (54.7%). The resistance of E. coli isolates to tetracycline (74.1%) was highest, followed by cephalothin (69.9%), doxycycline (66.5%), streptomycin (47.2%), ampicillin (46.2%), cefazolin (31.6%), enrofloxacin (31.0%). norfloxacin (28.2%). The most frequent resistance pattern was TE-D-CF-CIP-ENO-NOR-AM-S-C-SXT-AmC-CZ (14.7%), followed by CF (6.2%), TE (5.1%), TE-CF (4.5%) in 177 isolates from fishes and TE-D-CF (7.2%) followed by TE-D-CF-S (5.8%), CF and TE-D-S (3.6%) in 139 isolates from seawater.

Antimicrobial resistance in non-typhoidal Salmonella from human sources, Spain, 2001-2003

To determine the current state of antimicrobial resistance among non-typhoidal Salmonella strains isolated from humans in Spain. All strains of Salmonella from human sources received in the reference laboratory from 2001 to 2003 were serotyped and phage types were determined in the most common serovars. A systematic sampling procedure was carried out in order to obtain a random sample for susceptibility testing. The selected strains were tested for susceptibility to 12 different antimicrobial agents by a disc diffusion method using Mueller-Hinton agar. Results were scored as susceptible, moderately susceptible or resistant, according to CLSI criteria. From 2001 to 2003, 5777 strains of Salmonella were tested for susceptibility. Fifty per cent of strains of Salmonella Enteritidis were resistant to nalidixic acid. This was the most frequent resistance pattern of this serovar and it was characteristic of PT1, the most frequent phage type of Salmonella Enteritidis in Spain. Seventy-four per cent of Salmonella Typhimurium strains were resistant to four antibiotics or more. Resistance to ampicillin, chloramphenicol, streptomycin, sulphonamide and tetracycline was the most frequent resistance pattern of Salmonella Typhimurium and it was characteristic of DT104, the most frequent phage type in Spain. Sixty-nine per cent of Salmonella Hadar strains were resistant to at least four antibiotics. The results of our study showed both a worrying percentage of strains of Salmonella Enteritidis resistant to nalidixic acid and of strains of Salmonella Typhimurium with a pattern of resistance to four antibiotics or more. Surveillance of antimicrobial resistance should carry on and improve in order to be able to evaluate the control measures carried out for decreasing resistance in Salmonella, specifically that addressed to the prudent use of antimicrobial agents by farmers and veterinarians.

Aminoglycoside resistance patterns ofSerratia marcescensstrains of clinical origin

Aminoglycoside resistance patterns of 147 Serratia marcescens strains of clinical origin were studied. All strains analysed belonged to three different bacterial populations. The periods of study and the institutions the strains were isolated from correlated significantly with the resistance patterns shown by the strains. The most frequent resistance patterns found were the following: ACC (6')-I at the Hospital Infantil de México (Children's Hospital of México), and ANT (2'') + AAC(6')-I at the Instituto Nacional de Pediatría (INPed or National Institute of Pediatrics) in Mexico City. Furthermore, the isolation frequency of aminoglycoside-sensitive strains decreased remarkably at the INPed over a 12-year period. These results suggest that there has been a selection of Serratia marcescens strains that are very resistant to aminoglycosides.

Drug Resistance and R Plasmids in Escherichia coli Strains Isolated from Pork

Investigation in relation to R plasmids was performed on 217 strains of drug resistant Escherichia coli isolated from 100 samples of ground pork in 1972 to 1974.Drugs tested were 7 kinds such as tetracycline (TC), chloramphenicol (CM), streptomycin (SM), sulfanilamide (SA), kanamycin (KM), ampicillin (APC) and nalidixic acid (NA). The results were summarized as follows;1. Of 217 strains, about 95% were of multiple resistance, while the rest were of single resistance.2. Among 217 strains, 104 (47.9%) strains were found to carry R plasmids. Especially, multiple resistant strains with APC resistance carried R plasmids at the frequency of about 86% to 100%.3. The most frequent resistance pattern of R plasmids were multiple resistance.4. Transmission frequency of R plasmids derived to E. coli K-12 ML1410 were about 10-4 to 10-6 per one donor.5. Drug resistant E. coli strains carried two types of R plasmids i. e., fi- R (20%) and fi+ R plasmid (80%).