Comparison of Musculoskeletal Infections due to Nontyphoidal Salmonella Species and Staphylococcus aureus in Immunocompetent Children.

BACKGROUND: Nontyphoidal Salmonella species (NTS) rarely cause musculoskeletal infections in healthy children. Data on NTS musculoskeletal infections in healthy children are limited. No previous studies have directly compared children with NTS musculoskeletal infections with those with Staphylococcus aureus. METHODS: This was a case-control study of children 30 days-18 years old seen at Texas Children's Hospital between 2010 and 2017 with NTS musculoskeletal infections. Controls were children with S. aureus musculoskeletal infections matched on date of infection. Patients with known predisposing conditions were excluded. Demographic and clinical risk factors between the 2 groups were compared. RESULTS: From 2010 to 2017, 27 cases of NTS musculoskeletal infections were identified, 12 (46.0%) of which occurred in healthy children. The control group had 53 patients. Predictors of NTS musculoskeletal infections included exposure to reptiles [odds ratio (OR) 8.50, 95% confidence interval (CI): 11.24-58.23] and preceding gastrointestinal symptoms (OR 5.63, 95% CI: 1.45-21.89). Children with NTS musculoskeletal infections had greater odds of pelvic and/or spinal involvement than S. aureus controls (OR 5.32, 95% CI: 1.42-20.13). Complications occurred in 16.7% of NTS cases versus 32% of S. aureus controls. CONCLUSIONS: Healthy children with NTS musculoskeletal infections more frequently report reptile exposure and preceding gastrointestinal symptoms and have pelvic and spinal involvement compared with children with musculoskeletal infections due to S. aureus. NTS should be considered as a potential cause of musculoskeletal infections in children with these risk factors. In contrast to previous case reports and case series, children with NTS musculoskeletal infections had a low rate of complications.

Process risk model for Salmonella and ground chicken.

AIMS: To develop a process risk model (PRM) for evaluating the safety of individual lots of ground chicken (GC) contaminated with Salmonella (Salm). METHODS AND RESULTS: Data for prevalence, number and serotype of Salm were collected with 25 g samples of GC using a combination of methods (whole sample enrichment, quantitative polymerase chain reaction, cultural isolation and serotyping). These data were used to develop a predictive model for Salm contamination of GC as a function of serving size from 25 to 300 g. This model was combined with a model for thermal inactivation of Salm in GC and a dose-response model for Salm to develop a PRM in Excel that was simulated with NeuralTools and @Risk. Of 100, 25 g samples of GC examined, 19 tested positive for Salm. Three serotypes were isolated: Infantis (n = 13), Enteritidis (n = 5) and Typhimurium (n = 1). The number of Salm ranged from 0 to 2·56 log with a median of 0·93 log per 25 g of GC. The PRM predicted that Salm prevalence would increase (P < 0·05) from 19 to 57% to 82 to 93% as serving size increased from 25 to 100 g to 200 to 300 g. However, the total number of Salm in a 100-kg lot of GC and total severity of illness (TSI) were not affected (P> 0·05) by serving size. The PRM was also used to evaluate effects of serving size distribution, cooking, food consumption behaviour, consumer demographics and Salmonella virulence on TSI. CONCLUSIONS: How a lot of GC is partitioned and consumed does not affect TSI. Scenario analysis demonstrated that the PRM can integrate prevalence, number and serotype data for Salm with consumer handling, consumption and demographics data to identify safe and unsafe lots of GC for improved food safety and public health. SIGNIFICANCE AND IMPACT OF THE STUDY: Process-risk models like the one developed in this study represent a new, holistic approach to food safety that holds great promise for improving public health and reducing food recalls.

Fluoroquinolone resistance in Salmonella: insights by whole-genome sequencing.

Fluoroquinolone (FQ)-resistant Salmonella spp. were listed by the WHO in 2017 as priority pathogens for which new antibiotics were urgently needed. The overall global burden of Salmonella infections is high, but differs per region. Whereas typhoid fever is most prevalent in South and South-East Asia, non-typhoidal salmonellosis is prevalent across the globe and associated with a mild gastroenteritis. By contrast, invasive non-typhoidal Salmonella cause bloodstream infections associated with high mortality, particularly in sub-Saharan Africa. Most Salmonella strains from clinical sources are resistant to first-line antibiotics, with FQs now being the antibiotic of choice for treatment of invasive Salmonella infections. However, FQ resistance is increasingly being reported in Salmonella, and multiple molecular mechanisms are already described. Whole-genome sequencing (WGS) is becoming more frequently used to analyse bacterial genomes for antibiotic-resistance markers, and to understand the phylogeny of bacteria in relation to their antibiotic-resistance profiles. This mini-review provides an overview of FQ resistance in Salmonella, guided by WGS studies that demonstrate that WGS is a valuable tool for global surveillance.

Non-typhoidal Salmonella in Calabria, Italy: a laboratory and patient-based survey.

INTRODUCTION: Although there has been a decrease in the number of cases of salmonellosis in the European Union, it still represents the primary cause of foodborne outbreaks. In Calabria region, data are lacking for the incidence of human non-typhoid salmonellosis as active surveillance has never been carried out. OBJECTIVE: To report the results of a laboratory and patient-based morbidity survey in Calabria to describe the incidence and distribution of Salmonella serovars isolated from humans, with a focus on antimicrobial resistance patterns. METHODS: Positive cultures from human samples were collected from every laboratory participating in the surveillance, with a minimum set of information about each isolate. A questionnaire was then administered to the patients by telephone interview to assess the potential risk exposures.Salmonella isolates underwent biochemical identification, molecular analysis by PCR and antimicrobial susceptibility testing by the disk-diffusion method. RESULTS: During a 2-year period, 105 strains of Salmonella spp were isolated from samples of patients with diarrhoea, with the highest isolation rate for children aged 1-5 years. The standardised rate was 2.7 cases per 1 00 000 population. The most common Salmonella isolates belonged to monophasic variant of S. Typhimurium (S. 4,[5],12:i:-) (33.3%), followed by S. Typhimurium (21.9%). 30.5% of the isolates were susceptible to all microbial agents tested and the most common pan-susceptible serotype was S. Napoli (100%). S. 4,[5],12:i:- was resistant to ampicillin, streptomycin, sulfonamides and tetracyclines in 42.9% cases, while resistance to quinolones was seen in 14.3% of the isolates. CONCLUSIONS: The results provide evidence that an active surveillance system effectively enhances Salmonella notifications. The high prevalence of antimicrobial resistance, including resistance to quinolones and multiresistance, enforces the need to strengthen strategies of surveillance and monitoring of antimicrobial use.

Antibiofilm formation and anti-adhesive property of three mediterranean essential oils against a foodborne pathogen Salmonella strain.

Plant extracts, and their essential oils (EOs) are rich in a wide variety of secondary metabolites with antimicrobial properties. Our aim was to determine the bioactive compound in three mediterranean essential oils belonging to Lamiaceae family, Satureja montana L., Thymus vulgaris L. and Rosmarinus officinalis L., and to assess their antimicrobial, antibiofilm and anti-adhesive potentials against a foodborne pathogen Salmonella strain. The antibacterial activity of EOs and its biofilm inhibition potencies were investigated on 2 reference strains Salmonella typhimurium and 12 Salmonella spp. isolated from food. Biofilm inhibition were assessed using the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major components of the oils, but their concentrations varied greatly among the oils examined. Our results showed that S. montana L. and T. vulgaris L. essential oils possess remarkable anti biofilm, anti-adhesive and bactericidal properties, compared to R. officinalis EO. There is an indication that Rosmary EO might inhibit biofilm formation at higher concentrations. Therefore, the witer savory and thyme EOs represent a source of natural compounds that exhibit potentials for use in food systems to prevent the growth of foodborne bacteria and extend the shelf life of the processed food.

Reduction of subclinical Salmonella infection in fattening pigs after dietary supplementation with a ß-galactomannan oligosaccharide.

AIMS: To assess the efficacy of a ß-galactomannan oligosaccharide (ß-GMOS) for the control of Salmonella infection in fattening pigs. METHODS AND RESULTS: Three different doses (0.5, 3 and 2 kg ß-GMOS per ton of feed) were used during the entire period of growing in three similar and independent field trials carried out in a small fattening unit (≈ 100 pigs). Treatment was randomly assigned to half of the pens. Individual serum samples (20-25 per group) were collected at different times during the fattening period and a similar number of faecal samples during the fattening period and at slaughter. In addition, mesenteric lymph nodes were collected at slaughter. Herdcheck(®) Swine Salmonella ELISA was used for serological analyses, the ISO 6579:2002/Amd 1 : 2007 for bacteriology and the PFGE for molecular characterization of Salmonella strains. The addition of ≥ 2 kg t(-1) of ß-GMOS to the pig diet during the entire fattening period was associated with a reduction in Salmonella prevalence, shedding and seroconversion. CONCLUSIONS: Feed supplementation with ß-GMOS may be a useful complementary tool for the control of salmonellosis in fattening pigs. SIGNIFICANCE AND IMPACT OF THE STUDY: ß-GMOS may be a complementary way of reducing Salmonella shedding and infection in fattening pigs.

Presence of non-O157 Shiga toxin-producing Escherichia coli, enterotoxigenic E. coli, enteropathogenic E. coli and Salmonella in fresh beetroot (Beta vulgaris L.) juice from public markets in Mexico.

BACKGROUND: Unpasteurized juice has been associated with foodborne illness outbreaks for many years. Beetroot is a vegetable grown all over the world in temperate areas. In Mexico beetroot is consumed cooked in salads or raw as fresh unpasteurized juices. No data about the microbiological quality or safety of unpasteurized beetroot juices are available. Indicator bacteria, diarrheagenic Escherichia coli pathotypes (DEP) and Salmonella frequencies were determined for fresh unpasteurized beetroot juice from restaurants. RESULTS: One hundred unpasteurized beetroot juice samples were collected from public markets in Pachuca, Mexico. Frequencies in these samples were 100%, 75%, 53%, 9% and 4% of positive samples, for coliform bacteria, fecal coliforms, E. coli, DEP and Salmonella, respectively. Identified DEP included enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and non-O157 Shiga toxin-producing E. coli (STEC). Identified Salmonella serotypes included Typhimurium and Enteritidis. CONCLUSION: This is the first report of microbiological quality and atypical EPEC, ETEC, non-O157 STEC and Salmonella isolation from fresh raw beetroot juice in Mexico. Fresh raw beetroot juice from markets is very probably an important factor contributing to the endemicity of atypical EPEC, ETEC, non-O157 STEC and Salmonella-related gastroenteritis in Mexico.

Protective effects of zinc-bearing clinoptilolite on broilers challenged with Salmonella pullorum.

This study was conducted to evaluate the effects of zinc-bearing clinoptilolite (ZnCP) on broilers challenged with Salmonella pullorum for a 21-d feeding trial. A total of 240 one-day-old chickens was allocated into 4 treatment groups: 1) nonchallenged control (CON) fed basal diet; 2) S. pullorum-challenged control (SCC) fed basal diet; 3) Salmonella challenge fed basal diet plus antibiotic (ANT); 4) Salmonella challenge fed basal diet plus 0.2% ZnCP (ZnCP). Compared with CON, Salmonella challenge caused adverse effects on ADG (P<0.05), ADFI, feed/gain ratio in broilers, Salmonella and Lactobacillus colonies at 7 d (P<0.05) and 21 d, and serum diamine oxidase (DAO) activity. Moreover, the relative weight of spleen of 21-d birds, malondialdehyde (MDA) content of jejunual and ileal mucosa at 21 d, and the superoxide dismutase (SOD) activity of ileal mucosa were also significantly negatively affected by SCC treatment (P<0.05). Supplementation of ZnCP in basal diet significantly improved ADG and reduced Salmonella colonies in cecal contents and serum DAO activity both at 7 and 21 d (P<0.05), compared with SCC. Furthermore, supplementation with ZnCP as well as ANT significantly decreased the relative weight of spleen at 21 d, reduced MDA contents of jejunual and ileal mucosa at 21 d (P<0.05), and improved the SOD activity of ileal mucosa at 7 d as compared with SCC (P<0.05). The results suggested that ZnCP addition in feed exerted protective effects on performance and gut health of broilers against S. pullorum infection.

An unusual dual infection with Salmonella bredeney, including bacteraemia, and enterohaemorrhagic Escherichia coli O157 that posed a therapeutic dilemma.

In this case report, we describe an unusual case of a patient who had a dual infection with Salmonella bredeney including bacteraemia and enterohaemorrhagic Escherichia coli O157 following travel to Cyprus. This posed a therapeutic dilemma. We delayed treatment of the Salmonella infection until signs of colitis had resolved.

Serovariedades y patrones de susceptibilidad a los antimicrobianos de cepas de Salmonella aisladas de alimentos en Cuba / Serotypes and antimicrobial susceptibility patterns of Salmonella strains isolated from food in Cuba

The serotypes of 178 isolates of Salmonella enterica taken from food in different regions of Cuba between January 2008 and December 2009 were identified, and the antimicrobial susceptibility pattern of 100 selected isolates was determined by stratasampling. A total of 20 Salmonella serotypes were identified, with a predominance of S. Enteritidis (23%), S. Agona (13.5%), and S. London (11.2%). Of all the strains, 75%were resistant or presented intermediate resistance to at least one of the drugs tested, in the following order: tetracycline (70.7%), ampicillin (22.7%), and nalidixic acid (14.7%). Ten different resistance patterns were identified. The most frequent patternscorresponded to strains that were either drug-resistant or had intermediate resistance (89.3%). Three strains (identified as S. Infantis, S. Derby, and S. Enteritidis) were multiresistant, and one of them, S. Enteritidis, was not sensitive to either nalidixic acid or ciprofloxacin. To control salmonellosis, the importance of maximizing integrated health surveillance is emphasized.

Se describen los serotipos de 178 cepas de Salmonella enterica aisladas de alimentos en diferentes regiones de Cuba entre enero de 2008 y diciembre de 2009, y el patrón de susceptibilidada los antimicrobianos de 100 aislados seleccionados mediante muestreo por estratos. Se identificaron 20 serovariedades de Salmonella entre las que predominaron S. Enteritidis (23%);S. Agona (13,5%) y S. London (11,2%). Del total, 75% de las cepas fueron resistentes o presentaronresistencia intermedia a al menos uno de los fármacos probados, en el siguiente orden, según su frecuencia: tetraciclina (70,7%); ampicilina (22,7%) y ácido nalidíxico (14,7%). Seidentificaron 10 patrones de resistencia diferentes y predominaron las cepas resistentes o con resistencia intermedia a un fármaco (89,3%). Tres cepas (S. Infantis, S. Derby y S. Enteritidis)fueron multirresistentes y una, de S. Enteritidis, dio un resultado no sensible al ácido nalidíxico y la ciprofloxacina. Se destaca la necesidad de extremar la vigilancia sanitaria integrada en el país para el control de la salmonelosis.

[Serotypes and antimicrobial susceptibility patterns of Salmonella strains isolated from food in Cuba]. / Serovariedades y patrones de susceptibilidad a los antimicrobianos de cepas de Salmonella aisladas de alimentos en Cuba.

The serotypes of 178 isolates of Salmonella enterica taken from food in different regions of Cuba between January 2008 and December 2009 were identified, and the antimicrobial susceptibility pattern of 100 selected isolates was determined by strata sampling. A total of 20 Salmonella serotypes were identified, with a predominance of S. Enteritidis (23%), S. Agona (13.5%), and S. London (11.2%). Of all the strains, 75% were resistant or presented intermediate resistance to at least one of the drugs tested, in the following order: tetracycline (70.7%), ampicillin (22.7%), and nalidixic acid (14.7%). Ten different resistance patterns were identified. The most frequent patterns corresponded to strains that were either drug-resistant or had intermediate resistance (89.3%). Three strains (identified as S. Infantis, S. Derby, and S. Enteritidis) were multiresistant, and one of them, S. Enteritidis, was not sensitive to either nalidixic acid or ciprofloxacin. To control salmonellosis, the importance of maximizing integrated health surveillance is emphasized.

Thermal inactivation and postthermal treatment growth during storage of multiple Salmonella serotypes in ground beef as affected by sodium lactate and oregano oil.

We assessed the heat resistance of Salmonella in raw ground beef in both the absence and presence of sodium lactate, oregano oil, and in combinations of these 2 GRAS-listed ingredients, and determined their bactericidal or bacteriostatic activities during postthermal treatment storage at 15 degrees C. A cocktail of 8 serotypes of Salmonella spp. was inoculated into ground beef supplemented with sodium lactate (NaL) (1.5% and 3%) and/or oregano oil (0.5% and 1%) to obtain approximately 8 log CFU/g. The ground beef samples (3 g) were vacuum-packed and heated at 60, 65, or 71 degrees C in a circulating water bath for selected times to inactivate approximately 5 to 6 log CFU/g of the pathogen, and then stored at 15 degrees C for 15 and 30 d. Results show that especially at the lower cooking temperatures, addition of oregano oil increased the inactivation rate of Salmonella spp., whereas addition of NaL alone exhibited a protective effect against lethality and decreased the rate. Addition of combinations of oregano oil and NaL overcame this protective effect. During subsequent posttreatment storage for 15 d, Salmonella populations in the controls and in samples containing 0.5% oregano (60 and 65 degrees C) or 1% oregano oil (60 degrees C) increased to 4.5 to 6 log CFU/g. The values for all other samples were at or near undetectable levels. Results from the 30-d storage study were similar. These findings indicate that lactate and oregano oil may be used to render Salmonella spp. more susceptible to the lethal effect of heat and to inhibit growth of Salmonella spp. that survive heat treatments.

In vitro activity of methyl gallate isolated from galla rhois alone and in combination with ciprofloxacin against clinical isolates of salmonella.

Salmonella remains a primary cause of food poisoning worldwide, and massive outbreaks have been witnessed in recent years. Therefore, this study investigated the antimicrobial activity of methyl gallate (MG), which exhibited good antibacterial activity (MIC=3.9-125 mg/ml) against all the bacterial strains tested. In a checkerboard dilution test, MG markedly lowered the MICs of ciprofloxacin (CPFX) against Salmonella. The combined activity of CPFX and MG against Salmonella resulted in fractional inhibitory concentrations (FICs) ranging from 0.0037 to 0.015 and from 0.24 to 7.8 mg/ml, respectively. Meanwhile, the FIC index ranged from 0.31-0.37, indicating a marked synergistic relationship between CPFX and MG against Salmonella. Time-kill assays also showed a decrease in the CFU/ml between the combination and the more active compound. Therefore, this study demonstrated that MG and CPFX can act synergistically in inhibiting Salmonella in vitro.

A multi-center randomised controlled trial of gatifloxacin versus azithromycin for the treatment of uncomplicated typhoid fever in children and adults in Vietnam.

BACKGROUND: Drug resistant typhoid fever is a major clinical problem globally. Many of the first line antibiotics, including the older generation fluoroquinolones, ciprofloxacin and ofloxacin, are failing. OBJECTIVES: We performed a randomised controlled trial to compare the efficacy and safety of gatifloxacin (10 mg/kg/day) versus azithromycin (20 mg/kg/day) as a once daily oral dose for 7 days for the treatment of uncomplicated typhoid fever in children and adults in Vietnam. METHODS: An open-label multi-centre randomised trial with pre-specified per protocol analysis and intention to treat analysis was conducted. The primary outcome was fever clearance time, the secondary outcome was overall treatment failure (clinical or microbiological failure, development of typhoid fever-related complications, relapse or faecal carriage of S. typhi). PRINCIPAL FINDINGS: We enrolled 358 children and adults with suspected typhoid fever. There was no death in the study. 287 patients had blood culture confirmed typhoid fever, 145 patients received gatifloxacin and 142 patients received azithromycin. The median FCT was 106 hours in both treatment arms (95% Confidence Interval [CI]; 94-118 hours for gatifloxacin versus 88-112 hours for azithromycin), (logrank test p = 0.984, HR [95% CI] = 1.0 [0.80-1.26]). Overall treatment failure occurred in 13/145 (9%) patients in the gatifloxacin group and 13/140 (9.3%) patients in the azithromycin group, (logrank test p = 0.854, HR [95% CI] = 0.93 [0.43-2.0]). 96% (254/263) of the Salmonella enterica serovar Typhi isolates were resistant to nalidixic acid and 58% (153/263) were multidrug resistant. CONCLUSIONS: Both antibiotics showed an excellent efficacy and safety profile. Both gatifloxacin and azithromycin can be recommended for the treatment of typhoid fever particularly in regions with high rates of multidrug and nalidixic acid resistance. The cost of a 7-day treatment course of gatifloxacin is approximately one third of the cost of azithromycin in Vietnam. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN67946944.

An open randomized comparison of gatifloxacin versus cefixime for the treatment of uncomplicated enteric fever.

OBJECTIVE: To assess the efficacy of gatifloxacin versus cefixime in the treatment of uncomplicated culture positive enteric fever. DESIGN: A randomized, open-label, active control trial with two parallel arms. SETTING: Emergency Room and Outpatient Clinics in Patan Hospital, Lagankhel, Lalitpur, Nepal. PARTICIPANTS: Patients with clinically diagnosed uncomplicated enteric fever meeting the inclusion criteria. INTERVENTIONS: Patients were allocated to receive one of two drugs, Gatifloxacin or Cefixime. The dosages used were Gatifloxacin 10 mg/kg, given once daily for 7 days, or Cefixime 20 mg/kg/day given in two divided doses for 7 days. OUTCOME MEASURES: The primary outcome measure was fever clearance time. The secondary outcome measure was overall treatment failure (acute treatment failure and relapse). RESULTS: Randomization was carried out in 390 patients before enrollment was suspended on the advice of the independent data safety monitoring board due to significant differences in both primary and secondary outcome measures in the two arms and the attainment of a priori defined endpoints. Median (95% confidence interval) fever clearance times were 92 hours (84-114 hours) for gatifloxacin recipients and 138 hours (105-164 hours) for cefixime-treated patients (Hazard Ratio[95%CI] = 2.171 [1.545-3.051], p<0.0001). 19 out of 70 (27%) patients who completed the 7 day trial had acute clinical failure in the cefixime group as compared to 1 out of 88 patients (1%) in gatifloxacin group(Odds Ratio [95%CI] = 0.031 [0.004 - 0.237], p<0.001). Overall treatment failure patients (relapsed patients plus acute treatment failure patients plus death) numbered 29. They were determined to be (95% confidence interval) 37.6 % (27.14%-50.2%) in the cefixime group and 3.5% (2.2%-11.5%) in the gatifloxacin group (HR[95%CI] = 0.084 [0.025-0.280], p<0.0001). There was one death in the cefixime group. CONCLUSIONS: Based on this study, gatifloxacin is a better treatment for uncomplicated enteric fever as compared to cefixime. TRIAL REGISTRATION: Current Controlled Trials ISRCTN75784880.

Prevalence of antimicrobial resistance among Salmonella on midwest and northeast USA dairy farms.

The objective of this study was to determine the prevalence of antimicrobial resistance among Salmonella isolated from dairy herds in New York, Minnesota, Michigan, and Wisconsin, USA. Serogroup and antimicrobial susceptibility characteristics were determined for Salmonella from cattle and environmental samples collected during August 2000-October 2001 as part of a longitudinal study where 129 herds were visited at 2-month intervals. Salmonella isolates were tested (using a broth microdilution method) for susceptibility to amoxicillin/clavulanic acid, ampicillin, ceftiofur, ceftriaxone, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole. Of the 1506 isolates tested for minimum inhibitory concentrations to these 14 antimicrobial agents, 81.2% were pan-susceptible and for most herds (81.6%) the predominant antimicrobial resistance pattern was pan-susceptible. At least 1 Salmonella isolate resistant to 5 or more antimicrobial agents was found on 23.6% of herds. This resistance phenotype was most common among serogroups B and E1 and among samples from calves and farmer-designated sick cows. Resistant samples most frequently exhibited resistance to tetracycline, streptomycin, and/or ampicillin. No samples were resistant to ceftriaxone (though 13 were in the intermediate range), and very few samples were resistant to ciprofloxacin (n=1), nalidixic acid (n=5), or trimethoprim/sulfamethoxazole (n=7).

Multidrug resistance and distribution of Salmonella serovars in slaughtered pigs.

The present study was undertaken to estimate the occurrence and distribution of multidrug resistance (MDR) among Salmonella serovars isolated from slaughtered pigs at Debre Zeit, Ethiopia. A total of 501 different samples were examined of which 42 (41.6%) of 101 mesenteric lymph nodes, 22 (21.8%) of 101 tongues, 17 (16.8%) of 101 caecal contents, 11 (11.1%) of 99 livers and two (2%) of 99 muscle (diaphragm and abdomen) samples were Salmonella positive. Of the 94 Salmonella isolates representing 15 different serovars, 69 (73.4%) were multidrug resistant (resistance to two or more antimicrobials). Among the Salmonella serovars a high level of MDR was observed in S. Hadar, S. Kentucky, S. Blockley and S. Enteritidis mainly to tetracycline (88.6%), streptomycin (82.9%), nitrofurantoin (74.3%), nalidixic acid and ciprofloxacin (42.9% each), sulfisoxazole (21.1%) and spectinomycin (20%). The pattern of MDR varied from two to eight antimicrobials among the resistant Salmonella serovars. The common profiles of resistance among the MDR serovars were the combined resistance to nitrofurantoin, streptomycin and tetracycline (R type NitStrTet, 51.4%), ciprofloxacin, nalidixic acid and nitrofurantoin (R type CipNalNit, 10%), ciprofloxacin, nalidixic acid, spectinomycin, streptomycin, sulfisoxazole and tetracycline (R type CipNalSptStrSulTet, 14.3%) and to ciprofloxacin, kanamycin, nalidixic acid, neomycin, nitrofurantoin, streptomycin and tetracycline (R type CipKanNalNeoNitStrTet, 10%). Results of the present study indicate the widespread occurrence and distribution of MDR Salmonella serovars in slaughtered pigs which could be a potential source of human MDR Salmonella infections.

Antimicrobial resistance of Salmonella isolated from finishing swine and the environment of 60 Alberta swine farms.

The study objective was to describe and evaluate antimicrobial resistance profiles in Salmonella isolated from Alberta swine finishing farms. Salmonella isolates (n = 322) were obtained from 192 fecal and 84 environmental samples of the 60 Salmonella-positive swine finishing farms. Isolates were classified susceptible, intermediate or resistant based on NCCLS guidelines. More than half of the isolates (53.4%) were susceptible to all of the 18 antimicrobials in the testing panel. No resistance was observed to amikacin, amoxicillin/clavulanic acid, cefoxitin, ceftiofur, ceftriaxone, cephalothin, ciprofloxacin, imipenem or nalidixic acid. Less than 1% of isolates were resistant to apramycin, gentamicin and trimethoprim/sulfamethoxazole. Higher frequencies of resistance were observed for chloramphenicol (4.7%), ampicillin (7.8%), kanamycin (11.8%), sulfamethoxazole (21.1%), streptomycin (25.5%) and tetracycline (38.8%). Eleven Salmonella serovars had isolates with resistance to > or =3 antimicrobials. The most frequently resistant serovar was Salmonella Derby, with 27 (38.0%) isolates resistant to > or =3 antimicrobials, including resistance to five and six antimicrobials. An absence of resistance to cephalosporins and fluoroquniolones and a low proportion of isolates resistant to amikacin, amoxicillin/clavulanic acid, apramycin, gentamicin and trimethoprim/sulfamethoxazole are encouraging findings from public health and animal health perspectives. Frequent resistance observed for ampicillin, kanamycin, sulfamethoxazole, streptomycin and tetracycline, antimicrobials commonly used in veterinary medicine for decades, indicates an urgent need to utilize these antimicrobials more prudently if their benefits are to be preserved.