A comparative study on antimicrobial susceptibility of uroculturome of humans in health and urinary tract infections

Background:The uroculturome indicates the profile of culturable microbes inhabiting the urinary tract,and it is often required to do a urine culture to find an effective antimicrobial to treat urinary tract infections(UTIs).Methods:This study targeted to understand the profile of culturable pathogens in the urine of apparently healthy(128)and humans with clinical UTIs(161)and their antimicrobial susceptibility.All the urine samples were analyzed to quantify microbial load and determine the diversity and antimicrobial susceptibility of microbes following standard microbiological methods.Results:In urine samples from UTI cases,microbial counts were 1.2×10^(4)±6.02×10^(3) colony-forming units(cfu)/mL,while in urine samples from apparently healthy humans,the average count was 3.33±1.34×10^(3) cfu/mL.In eight samples(six from UTI cases and two from apparently healthy people,Candida(C.albicans 3,C.catenulata 1,C.krusei 1,C.tropicalis 1,C.parapsiplosis 1,C.gulliermondii 1)and Rhizopus species(1)were detected.Candida krusei was detected only in a single urine sample from a healthy person and C.albicans was detected both in urine of healthy and clinical UTI cases.Gram-positive(G+ve)bacteria were more commonly(Odds ratio,1.98;CI99,1.01-3.87)detected in urine samples of apparently healthy humans,and Gram-negative(G−ve)bacteria(Odds ratio,2.74;CI99,1.44-5.23)in urines of UTI cases.From urine samples of 161 UTI cases,a total of 90 different types of microbes were detected and,73 samples had only a single type of bacteria.In contrast,49,29,3,4,1,and 2 samples had 2,3,4,5,6 and 7 types of bacteria,respectively.The most common bacteria detected in urine of UTI cases was Escherichia coli(52 samples),in 20 cases as the single type of bacteria,other 34 types of bacteria were detected in pure form in 53 cases.From 128 urine samples of apparently healthy people,88 types of microbes were detected either singly or in association with others,from 64 urine samples only a single type of bacteria was detected while 34,13,3,11,2 and 1 sample yielded 2,3,4,5,6 and seven types of microbes,respectively.In the urine of apparently healthy humans too,E.coli was the most common bacteria,(10 samples)followed by Staphylococcus haemolyticus(9),S.intermedius(5),and S.aureus(5),and similar types of bacteria also dominated in cases of mixed occurrence,E.coli was detected in 26,S.aureus in 22 and S.haemolyticus in 19 urine samples,respectively.G+ve bacteria isolated from urine samples’irrespective of health status were more often(P<0.01)resistant than G−ve bacteria to ajowan oil,holy basil oil,cinnamaldehyde,and cinnamon oil,but more susceptible to sandalwood oil(P<0.01).However,for antibiotics,G+ve were more often susceptible than G−ve bacteria to cephalosporins,doxycycline,and nitrofurantoin.Conclusion:The study concludes that to understand the role of good and bad bacteria in the urinary tract microbiome more targeted studies are needed to discern the isolates at the pathotype level.Further,the study suggests the use of antibiotics by observing good antibiotic stewardship following antibiotic susceptibility testing only.

Urinary Tract Infection among Adults Seeking Medicare at Kiambu Level 5 Hospital, Kenya: Prevalence, Diversity, Antimicrobial Susceptibility Profiles and Possible Risk Factors

Urinary tract infections are among the most prevalent extra-intestinal infections, with high prevalence globally. This cross-sectional study established prevalence of bacterial aetiology causing urinary tract infection (UTI) and their antimicrobial susceptibility profiles. A questionnaire was used to capture socio-demographic data and possible UTI risk factors among the 206 consented adults seeking medicare at Kiambu Level 5 Hospital. The collected midstream urine samples were subjected to dipstick analysis, microscopy and culture for UTI diagnosis. Results: The overall prevalence rate of UTIs was 27.6%, with women’s prevalence rate being significantly higher at 80.7% compared to men 19.2%. Pregnant women had UTI prevalence at 34% which was higher than other sets of participants. Women who did not frequently change their underpants daily had a higher UTI cases at 34.8%. Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae were the most prevalent bacterial pathogens at 38.5%, 21% and 19.3%, respectively. Antimicrobial sensitivity analysis revealed high resistances towards Sulfamethoxazole and Ampicillin at range between 50% - 85%, suggesting that these drugs are no longer effective for UTI empirical treatment. The resistance patterns towards Cefotaxime, Cefepime and Ciprofloxacin were below 40%. However, more resistance patterns at a range between 14% - 40% revealed towards Amoxicillin-clavulanic and Nitrofurantoin imply that these are drugs remain potent but there is the need to revise the current UTI management guidelines. In addition, to elude treatment failure, innovation of prophylactic measures is key to halt UTI contraction and offer support to pharmaceutical industries that have fewer new antibiotics in the pipeline.

Antimicrobial Resistance,Virulence Profile,and Molecular Characterization of Listeria monocytogenes Isolated from Ready-to-eat Food in China,2013-2014

We aimed to investigate the potential pathogenic profile and antibiotic resistance of Listeria monocytogenes isolated from ready-to-eat food in China.Antimicrobial resistance was determined by broth microdilution following the Clinical and Laboratory Standards Institute protocol Molecular serotyping,virulence,and resistance genes were identified using PCR.Multi-locus

Antimicrobial susceptibility profile of community acquired and nosocomial isolates of Escherichia coli from clinical blood culture specimens at a Nigerian university teaching hospital

Objective:To ascertain the antibiotic susceptibility patterns of Escherichia coli recovered from blood culture specimens in Calabar.Nigeria.Methods:The study was retrospective in nature and was carried out at University of Calabar Teaching Hospital(UCTH) Calabar.Data generated from blood culture specimens over a five year period(Feb.2004-Feb.2009) was compiled, relevant information such as age,sex,organism recovered and antibiotic susceptibility patterns were obtained from patients records.Samples were collected,transported,stored and processed using standard laboratory procedures.Data obtained was analysed using Epi Info 6 statistical software.Results:Escherichia coli was responsible for 15.3%(31/203) of the blood infections being the third most common microorganism encountered.The community acquired(CA) isolates of the organism were significantly less resistant(P【0.05),compared to the nosocomial(NC) isolates against ampicillin.cloxacillin,amoxicillin,tetracycline,co-trimoxazole.chloramphenicol and erythromycin.The sensitivity of both the NC and CA isolates of Escherichia coli to amikacin, augmentin,ofloxacin,ciprofloxacin,ceftazidime,cefuroxime,ceftriaxone and rifampicin was generally high(80-100%) with no significant difference(P】0.05).Majority(】95.0%) of the NC isolates of Escherichia coli were resistant to six of the antibiotics tested.Conclusions:Control mechanisms for hospital acquired infections should be stepped up so as lo limit the spread of the highly resistant bacterial strains.Also the sale and consumption of antibiotics by the public need to be regulated.

Antimicrobial Drug Resistance and Plasmid Profiles of <i>Salmonella</i>Isolates from Humans and Foods of Animal Origin in Uganda

Salmonella organisms are among the most common causes of human bacterial gastroenteritis worldwide, and food animals are important reservoirs of these bacteria. A further danger lies in the development of drug resistance in these organisms, primarily driven by non-prudent overuse of antiinfectives. The current study compared the plasmid profiles and drug susceptibility patterns of Salmonella isolates from man and foods of animal origin in Uganda. A total of 92 Salmonella isolates (58 from man and 34 from foods of animal origin) were analyzed. Identification was done by using biochemical tests;plasmid profiling by agarose gel electrophoresis while susceptibility testing to tetracycline, ampicillin, chloramphenicol, nalidixic acid, trimethoprim-sulphamethoxazole, ciprofloxacin, ceftriaxone and tetracycline were done by the Kirby Bauer Disc Diffusion method. Among the human isolates, 57/58 (98.3%, 95% CI, 91.8% - 99.9%) were susceptible to Ciprofloxacin compared to 32/34 (94.1%, 95% CI, 81.9% - 91%) of animal-derived isolates. On the other hand, 48/58 (82.7%, 95% CI, 71.4% - 91%) human-derived isolates were resistant to Trimethoprim sulfamethoxazole compared to 29/34(85.3%) of the animal-derived isolates. Fifty four percent (n = 50) of the all the isolates were resistant to at least three antibiotics whereas only 2.2% (n = 2) were susceptible to all the seven drugs tested. Most worrying, however, was the fact that only 45% percent of the isolates were sensitive to all the three drugs (chloramphenicol, nalidixic acid and ciprofloxacin) commonly used in the treatment of salmonellosis in this setting. The risk of ampicillin resistance was three times more likely to occur in animal-derived as compared to human-derived isolates (Odds Ratio = 2.705, 95% CI, 1.3 - 5.8) as was that to nalidixic acid (Odds Ratio = 2.895, 95% CI, 1.17 - 7.2). Plasmid profile analysis showed eight clusters comprising of 68.7% (46/67) of the isolates. In five of the eight clusters, there were both animal and human-derived isolates. Resistant strains of Salmonella are common in this setting and meat/meat products are the commonest source of infection. A majority of the isolates are multi-drug resistant, and there is evidence of cross-species transmission of plasmids, and possibly drug resistance, between animals and humans.

Antimicrobial susceptibility testing for Helicobacter pylori in times of increasing antibiotic resistance

The gram-negative bacterium Helicobacter pylori(H.pylori)causes chronic gastritis,gastric and duodenal ulcers,gastric cancer and mucosa-associated lymphoid tissue lymphoma.Treatment is recommended in all symptomatic patients.The current treatment options for H.pylori infection are outlined in this review in light of the recent challenges in eradication success,largely due to the rapid emergence of antibiotic resistant strains of H.pylori.Antibiotic resistance is a constantly evolving process and numerous studies have shown that the prevalence of H.pylori antibiotic resistance varies significantly from country to country,and even between regions within the same country.In addition,recent data has shown that previous antibiotic use is associated with harbouring antibiotic resistant H.pylori.Local surveillance of antibiotic resistance is warranted to guide clinicians in their choice of therapy.Antimicrobial resistance is assessed by H.pylori culture and antimicrobial susceptibility testing.Recently developed molecular tests offer an attractive alternative to culture and allow for the rapid molecular genetic identification of H.pylori and resistance-associated mutations directly from biopsy samples or bacterial culture material.Accumulating evidence indicates that surveillance of antimicrobial resistance by susceptibility testing is feasible and necessary to inform clinicians in their choice of therapy for management of H.pylori infection.

Prevalence and antimicrobial resistance pattern of bacterial strains isolated from patients with urinary tract infection in Messalata Central Hospital, Libya

Objective: To investigate the prevalence of urinary tract infection among patients at Messalata Central Hospital, Libya, to identify the causative bacteria, and to explore their resistance pattern to antimicrobials. Methods: A total number of 1 153 urine samples were collected from patients, who attended daily to Messalata Central Hospital, Libya, in a study extended for one year. Antimicrobial susceptibility testing and isolates typing were done using Phoenix BD(BD diagnostic). Resistance was confirmed manually using agar disk diffusion method. Results: Of the 1 153 urine samples tested, 160(13.9%) samples were positive, from which 17 different, solely Gram negative, uropathogens were identified. Escherichia coli were the most prevalent(55.6%) bacteria, followed by Klebsiella pneumoniae subspecies pneumoniae(16.3%), Proteus mirabilis(6.3%), Pseudomonas aeruginosa(5.6%), Enterobacter cloacae and Klebsiella oxytoca(2.5%, each), Citrobacter koseri and Providencia rettgeri(1.9%, each), Acinetobacter baumannii, Enterobacter aerogenes and Proteus vulgaris(1.3%, each), and Aeromonas caviae, Citrobacter freundii, Cronobacter sakazakii, Enterobacter amnigenus biogroup 2, Pseudomonas putida and Serratia marcescens(0.6%, each). The isolated uropathogens showed increased levels of resistance ranged from 10.5% to 64.5%, with an overall resistance of 28.9%. Amikacin was the most effective antimicrobial followed by Imipenem and Meropenem(0%, 0.6% and 2.5% resistance, respectively); while, Cephalothin and Ampicillin were the least(80.6% and 90.0% resistance, respectively) effective. Conclusions: The obtained results emphasized the emergence of highly resistant bacteria to most of tested antimicrobials and raise the alarm for physicians to change their treatment pattern depending on antimicrobial susceptibility results.

Analysis on Antimicrobial Resistance of Clinical Bacteria Isolated from County Hospitals and a Teaching Hospital

The distinction of antimicrobial resistance of clinical bacteria isolated from county hospitals and a teaching hospital was investigated. Disc diffusion test was used to study the antimicrobial resistance of isolates collected from county hospitals and a teaching hospital. The data was analyzed by WHONET5 and SPSS statistic software. A total of 655 strains and 1682 strains were collected from county hospitals and a teaching hospital, respectively, in the year of 2003. The top ten pathogens were Coagulase negative staphylococci （CNS）, E. coil, Klebsiella spp. , S. areus, P. aeruginosa, Enterococcus spp. , Enterobacter spp. , otherwise Salmonella spp. , Proteus spp. , Shigella spp. in county hospitals and Streptococcus spp. , Acinetobacter spp. , X. maltophilia in the teaching hospital. The prevalence of multi-drug resistant bacteria was 5 % （4/86） of methicillin-resistant S. areus （MRSA）, 12 % （16/133） and 15.8 % （9/57） of extended-spectrum β-lactamases producing strains of E. coil and Klebsiella spp. , respectively, in county hospitals. All of the three rates were lower than that in the teaching hospital and the difference was statistically significant （P〈0. 01）. However, the incidence of methicillin-resistant CNS （MRCNS） reached to 70 % （109/156） in the two classes of hospitals. Generally, the antimicrobial resistant rates in the county hospitals were lower than those in the teaching hospital, except the resistant rates of ciprofloxacin, erythromycin, clindamycin, SMZco which were similar in the two classes of hospitals. There were differences between county hospitals and the teaching hospital in the distribution of clinical isolates and prevalence of antimicrobial resistance. It was the basis of rational use of antimicrobial agents to monitor antimicrobial resistance by each hospital.

Antimicrobial susceptibility testing before first-line treatment for Helicobacter pylori infection in patients with dual or triple antibiotic resistance

To evaluate the efficacy of antimicrobial susceptibility-guided therapy before first-line treatment for infection in patients with dual or triple antibiotic resistance.METHODSA total of 1034 patients infected by Helicobacter pylori (H. pylori) during 2013-2014 were tested for antimicrobial susceptibility. 157 of 1034 (15%) patients showed resistance to two (127/1034; 12%) and to three (30/1034; 3%) antibiotics. Sixty-eight patients with dual H. pylori-resistance (clarithromycin, metronidazole or levofloxacin) were treated for 10 d with triple therapies: OAL (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and levofloxacin 500 mg b.i.d.) 43 cases, OAM (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and metronidazole 500 mg b.i.d.) 12 cases and OAC (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and clarithromycin 500 mg b.i.d.) 13 cases based on the antimicrobial susceptibility testing. Twelve patients showed triple H. pylori-resistance (clarithromycin, metronidazole and levofloxacin) and received for 10 d triple therapy with OAR (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and rifabutin 150 mg b.i.d.). Eradication was confirmed by 13C-urea breath test. Adverse effects and compliance were assessed by a questionnaire.RESULTSIntention-to-treat eradication rates were: OAL (97.6%), OAM (91.6%), OAC (92.3%) and OAR (58.3%). Cure rate was significantly higher in naïve patients treated with OAR-10 compared to patients who had two or three previous treatment failures (83% vs 33%). Adverse events rates for OAL, OAM, OAC and OAR were 22%, 25%, 23% and 17%, respectively, all of them mild-moderate.CONCLUSIONAntimicrobial susceptibility-guided triple therapies during 10 d for first-line treatment leads to an eradication rate superior to 90% in patients with dual antibiotic H. pylori resistance.

Prevalence and Antimicrobial Susceptibility Pattern of Streptococcus pneumoniae at General Hospital in the Central Region of Japan from December 2013 to February 2014

Streptococcus pneumonia infection is important cause of morbidity and mortality. This study was conducted to find out the prevalence and antimicrobial susceptibility pattern of Streptococcus pneumoniae isolates at general hospitalin the central region of Japan from December 2013 to February 2014. Streptococcus pneumoniae was identified by standard laboratory procedure. Antimicrobial susceptibility testing was performed by micro dilution assay according to CLSI recommendation. One hundred fifty-three Streptococcus pneumoniae were isolated among which 80 (52.2%) were males and 73 (47.8%) were females. Nasal discharge (134%/87.6%) contributed more than other biological materials. The age incidence of (0 - 1) years, (1 - 10) years, (11 - 40) years, (41 - 60) years and >60 years age groups were 26 (17.0%), 110 (71.9%), 3 (2.0%), 10 (6.5%), and 4 (2.6%) respectively. Positive samples were received mostly from the pediatrics (137%/89.5%), respiratory medicine (12%/7.8%) and lowest from gastroenterology (1%/0.6%) and neurology (1/ 0.6%) department. Vancomycin and rifampicin were the most active antibiotics with 100% susceptibility rates. The next best were levofloxacin, penicillin G and ceftriaxone. Our study revealed that 82 Streptococcus pneumonia isolates had multidrug resistant ability (53.6%). Streptococcus pneumoniae infection spreads among community easily and inappropriate use of antibiotics contributes to their resistance. Continuous antimicrobial susceptible surveys are essential to guide policy on the adequate use of antibiotics to reduce the morbidity and mortality and reduce the emergency of antimicrobial resistance.

Antimicrobial Susceptibility Profiles among <i>Escherichia coli</i>Strains Isolated from Athi River Water in Machakos County, Kenya

Antimicrobial use in agriculture, livestock and human health has increased over the years leading to the increase in antimicrobial resistance that can also find its way to the aquatic environment. Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of multidrug resistant (MDR) strains to animals and humans using water. A total of 318 water samples were collected from six different sampling points along Athi River and E. coli isolates were subjected to Kirby-Bauer diffusion method for antimicrobial susceptibility testing. The total mean coliform count of the sampled sites was 2.7 × 104 (cfu/mL). E. coli isolates were most resistant to ampicillin (63.8%) and most susceptible to gentamicin (99.4%). MDR strains (resistance to ≥3 classes of antibiotics) accounted for 65.4% of all the isolates. The site recorded to have human industrial and agricultural zone activities had strains that were significantly more resistant to ampicillin, cefoxitin, amoxicillin/clavulanic acid (P ≤ 0.05) than isolates from the section of the river traversing virgin land and land with minimum human activities. This study indicates that E. coli strains isolated from Athi River were highly MDR and most resistant to some antimicrobial classes (ampicillin and cefoxitin) which constitute a potential risk to human and animal health.

Bacteriological Profile, Antimicrobial Susceptibility Patterns and Predictors of Bacteremia in Neonates with Clinical Sepsis at KCMC Hospital, Northern Tanzania

Background: Despite a significant decline in neonatal deaths in the last 20 years (5 million in 1990 to 2.4 million in 2019), the risk of death is still high, especially in developing countries. In Tanzania, neonatal sepsis is the third leading cause of neonatal death, accounting for 25% of all deaths. The rising global threat of antimicrobial resistance and the rising burden of neonatal death due to neonatal sepsis have been of great concern and have delayed progress toward reaching SDG goal 3.2 by 2030. This study aims to determine the bacteriological profile, antibiotic susceptibility patterns, and predictors of bacteremia among neonates with clinical sepsis at KCMC Hospital in Northern Tanzania. Methodology: This study had a cross-sectional design conducted at KCMC Hospital, Northern Tanzania. The study population was neonates admitted to the neonatal unit at KCMC Hospital. Data were collected using questionnaires and blood cultures from neonates. Frequencies and proportions were used to summarize categorical variables, while continuous variables were summarized using mean and standard deviation. The frequencies and proportions of bacteria isolated and the antimicrobial susceptibility results were analyzed and compared using Pearson’s chi-square test and Fisher’s exact test where applicable. Modified Poisson regression model was used to determine factors associated with positive blood culture. Results: Out of 411 neonates with a clinical diagnosis of neonatal sepsis, 175 (42.9%) had positive blood cultures. Gram-positive bacteria were most frequently isolated at 52.3%, and gram-negative bacteria were 47.7%. Coagulase-negative Staphylococcus (30.7%) and Staphylococcus aureus (19.9%) were the predominant gram-positive isolates. Gram-negative isolates were Klebsiella spp 47 (26.7%), E. coli 10 (5.7%), and Citrobacter spp 10 (5.1%). The gram-positive isolates were sensitive to vancomycin, piperacillin/tazobactam, and ceftazidime, whereas the gram-negative were sensitive to amikacin, meropenem, and vancomycin. The study did not find statistically significant associations between clinical factors and positive blood cultures in bacteremia. Conclusion: Gram-positive bacteria are the dominant pathogens in early-onset and late-onset neonatal sepsis. High levels of resistance to ampicillin and ceftriaxone and moderate resistance to gentamycin were observed in both gram-positive and gram-negative bacteria. Gram-positive organisms exhibit better susceptibility rates to vancomycin and ciprofloxacin, while gram-negative micro-organisms are more sensitive to amikacin and meropenem. An effective initial treatment approach for neonatal sepsis would involve a combination of drugs.

Importance of antimicrobial susceptibility testing for the management of eradication in Helicobacter pylori infection

The management of Helicobacter pylori(H. pylori) infection treatment differs from the common treatment protocol for other infectious diseases. Because culture-or molecular-guided approaches face several practical issues, such as the invasive procedures required to obtain gastric biopsy specimens and the lack of availability of routine laboratory testing in some places, H. pylori treatment includes the administration of two or three empirically selected antibiotics combined with a proton pump inhibitor rather than evidence-based eradication treatment. The efficacy of empirical therapy is decreasing, mostly due to increasing multiple resistance. Multiresistance to levofloxacin, clarithromycin, and metronidazole, which are commonly used in empirical treatments, appears to have increased in many countries. Mutations play a primary role in the antimicrobial resistance of H. pylori, but many different mechanisms can be involved in the development of antibiotic resistance. Determining and understanding these possible mechanisms might allow the development of new methods for the detection of H. pylori and the determination of antimicrobial resistance. A treatment based on the detection of antimicrobial resistance is usually more effective than empirical treatment. Nevertheless, such an approach before treatment is still not recommended in the Maastricht guidelines due to the difficulty associated with the routine application of available cultureor molecular-based susceptibility tests, which are usually administered in cases of treatment failure. The management of first and rescue treatments requires further research due to the steadily increase in antimicrobial resistance.

Antimicrobial Susceptibility of Multidrug-Resistant <i>Acinetobacter baumanii</i>in a Teaching Hospital: A Two-Year Observation

Multidrug-resistant (MDR) Acinetobacter baumanii (A. baumanii) caused hospital acquired infection, typically in critical-ill patients with medical devices. This is a retrospective descriptive study on epidemiology and microbiology data to determine the antimicrobial susceptibility pattern of MDR-Acinetobacter baumanii isolates from a teaching hospital in Tangerang, Indonesia from Januari 2013 to December 2014. A total of 84 A. baumanii were collected. Patients suffering from respiratory tract infection had the highest number (41.7%) of A. baumanii isolate. There were 39 (46.6%) patients admitted in critical care. A. baumanii isolates in this study mostly were multidrug-resistant organisms with low susceptibility level to 11 antibiotic tested, 44% - 69% in 2013 and 26% - 67% in 2014. A high susceptibility level was observed to amikacin (80% and 79% in 2013, 2014 consecutively) and trimethoprim-sulfamethoxazole (73% and 72% in 2013, 2014 consecutively). A. baumanii is a hospital acquired pathogen in critically-ill patients. The susceptibility pattern of this study result showed MDR organism. There was a sharp decrease of susceptibility in all antibiotics studied from 2013 to 2014 except amikacin and trimethoprim-sulfamethoxazole.

Trends in Antimicrobial Resistance against Enterobacteriaceae Strains Isolated from Blood： A 10-year Epidemiological Study in China's Mainland （2004-2014）

Background：Antimicrobial resistance is a serious problem that compromises the empirical treatment of infections,resulting in a lack of effective antibiotics and high medical expenses.Here,we aimed to monitor the trends in antimicrobial resistance among Enterobacteriaceae isolated from blood samples in China's Mainland.Methods：A total of 2240 Enterobacteriaceae isolates from blood were collected from hospitalized patients at 19 tertiary hospitals between October 2004 and June 2014.The minimum inhibitory concentrations of all isolates were determined using the agar dilution method according to the Clinical and Laboratory Standards Institute 2016 guidelines.Results：The most commonly isolated bacteria were Escherichia coli,compromising 47.0% （1053/2240） of the total isolates,followed byKlebsiella spp.（26.3%）,Sahnonella spp.（10.4%）,and Enterobacter spp.（9.2%）.The detection rates of extended-spectrum β-lactamases （ESBLs） among E.coli were 68.9% （2004-2005）,73.2% （2007-2008）,67.9% （2009-2010）,72.6% （2011-2012）,and 58.4% （2013-2014）,whereas those in ESBL-producing Klebsiellapneumoniae were slightly decreased （75.9%,50.0%,41.4%,40.2%,and 43.0%,respectively）.Carbapenems were the most potent agents against the Enterobacteriaceae isolates,followed by moxalactam,tigecycline,and amikacin.However,there was a decrease in the susceptibility rates for carbapenems in all species,particularly K.pneumoniae （decreased by 10.6% for imipenem） and Enterobacter aerogenes （decreased by 2 l.1% for imipenem）.Reviving antibiotics （tigecycline and polymyxins） showed good in vitro activity against Enterobacteriaceae.Conclusions：The activity of antibiotics against Enterobacteriaceae isolated from blood was decreased overall.Large proportions of ESBL-producing isolates were identified among E.coli and Klebsiella spp.Carbapenem-resistant isolates have become a major challenge in the treatment of infections.

Genotypic Characterization of Methicillin-resistant Staphylococcus aureus Isolated from Pigs and Retail Foods in China

Objective To investigate the genotypic diversity of Methicillin-resistant Staphylococcus aureus （MRSA） isolated from pigs and retail foods from different geographical areas in China and further to study the routes and rates of transmission of this pathogen from animals to food. Methods Seventy-one MRSA isolates were obtained from pigs and retail foods and then characterized by multi-locus sequencing typing （MLST）, spa typing, multiple-locus variable number of tandem repeat analysis （MLVA）, pulsed-field gel electrophoresis （PFGE）, and antimicrobial susceptibility testing. Results All isolated MRSA exhibited multi-drug resistance （MDR）. Greater diversity was found in food-associated MRSA （7 STs, 8 spa types, and 10 MLVA patterns） compared to pig-associated MRSA （3 STs, 1 spa type, and 6 MLVA patterns）. PFGE patterns were more diverse for pig-associated MRSA than those of food-associated isolates （40 vs. 11 pulse types）. Among the pig-associated isolates, CC9-ST9-t899-MC2236 was the most prevalent clone （96.4%）, and CC9-ST9-t437-MC621 （20.0%） was the predominant clone among the food-associated isolates. The CC9-ST9 isolates showed significantly higher antimicrobial resistance than other clones. Interestingly, CC398-ST398-t034 clone was identified from both pig- and food-associated isolates. Of note, some community- and hospital-associated MRSA strains （t030, t172, t1244, and t4549） were also identified as food-associated isolates. Conclusion CC9-ST9-t899-MC2236-MDR was the most predominant clone in pigs, but significant genetic diversity was observed in food-associated MRSA. Our results demonstrate the great need for improved surveillance of MRSA in livestock and food and effective prevention strategies to limit MDR-MRSA infections in China.

Epidemiology and antimicrobial resistance of clinical isolates about hospital infection from patients with hematological diseases

Objective To investigate the epidemiology and anti-biotic resistance of isolates from hospitalized patients with hematological disease from 2005 to 2011. Methods A total of 1 453 bacterial strains were isolated from

Antimicrobial susceptibility testing in veterinary medicine:performance,interpretation of results,best practices and pitfalls

The performance of antimicrobial susceptibility testing(AST)of bacteria and the interpretation of AST results for bacteria isolated from animals are complex tasks which must be performed using standard published methodology and overseen by experts in clinical microbiology and in consultation with clinical pharmacologists.Otherwise,AST has significant potential for errors and mistakes.In this review,we provide guidance on how to correctly perform AST of bacteria isolated from animals and interpret the AST results.Particular emphasis is placed on the various approved or published methodologies for the different bacteria as well as the application of interpretive criteria,including clinical breakpoints and epidemiological cut-off values(ECVs/ECOFFs).Application of approved interpretive criteria and definitions of susceptible,susceptible dose-dependent,nonsusceptible,intermediate,and resistant for clinical breakpoints as well as wild-type and non-wildtype for ECVs,are explained and the difficulties resulting from the lack of approved clinical breakpoints for other bacteria,indications,and animal species is discussed.The requirement of quality controls in any AST approach is also emphasized.In addition,important parameters,often used in monitoring and surveillance studies,such as MIC50,MIC90,and testing range,are explained and criteria for the classification of bacteria as multidrug-resistant,extensively drug-resistant or pandrug-resistant are provided.Common mistakes are presented and the means to avoid them are described.To provide the most accurate AST,one must strictly adhere to approved standards or validated methodologies,like those of the Clinical and Laboratory Standards Institute or other internationally accepted AST documents and the detailed information provided therein.

2015—2021年CHINET临床分离葡萄球菌属细菌耐药性变迁

目的了解2015-2021年中国不同地区临床分离葡萄球菌属细菌的分布及耐药变迁。方法按CHINET中国细菌耐药监测网统一的技术方案对临床分离的葡萄球菌采用纸片法和商品化药敏试验测试仪(机器法)进行药物敏感性试验;收集2015-2021年CHINET的葡萄球菌耐药监测数据,使用WHONET 5.6软件统计并按2021年CLSI折点标准判读结果。结果2015-2021年共分离非重复葡萄球菌属细菌204771株,其中金黄色葡萄球菌136731株(66.8%),凝固酶阴性葡萄球菌68040株(33.2%),7年间两者检出率均无明显变化。金黄色葡萄球菌主要分离自呼吸道标本(38.9±5.1)%、伤口脓液分泌物(33.6±4.2)%、血液(11.9±1.5)%;凝固酶阴性葡萄球菌主要分离自血液(73.6±4.2)%、脑脊液(12.1±2.5)%、胸腹水(8.4±2.1)%。金黄色葡萄球菌的科室来源主要为ICU(17.0±7.3)%、门急诊(11.6±1.7)%、外科(11.2±0.9)%;凝固酶阴性葡萄球菌的科室来源主要为ICU(32.2±9.7)%、门急诊(12.8±4.7)%、内科(11.2±1.9)%。金黄色葡萄球菌、凝固酶阴性葡萄球菌中甲氧西林耐药株的总体检出率分别为32.9%、74.1%,7年间MRSA检出率从42.1%下降至29.2%,MRCNS检出率从82.1%下降至68.2%。除甲氧苄啶-磺胺甲噁唑外,MRSA对各类抗菌药物的耐药率均高于MSSA。MRSA对庆大霉素、利福平、左氧氟沙星耐药率有所下降;MRCNS对庆大霉素、红霉素、利福平、甲氧苄啶-磺胺甲噁唑的耐药率有所下降,对左氧氟沙星的耐药率有所上升。未发现对万古霉素耐药的葡萄球菌菌株。对利奈唑胺耐药的MRCNS有所增多,7年间耐药率从0.2%上升至2.3%。结论葡萄球菌属细菌仍是革兰阳性菌中最主要的细菌。MRSA和MRCNS亦仍然是革兰阳性菌中最主要的耐药细菌。至今未发现对万古霉素和利奈唑胺耐药的金黄色葡萄球菌,但已有利奈唑胺耐药的MRCNS菌株检出,应加强监测和关注。

2015-2021年CHINET尿液分离菌分布和耐药性变迁

目的了解2015-2021年CHINET细菌耐药监测网中尿液分离菌的分布和耐药性。方法收集CHINET细菌耐药监测网51家医疗机构2015-2021年所有尿液标本临床分离菌的耐药监测数据资料,采用WHONET 5.6软件进行统计分析。结果2012-2021年尿液标本共分离细菌261893株,其中革兰阳性菌62219株,占23.8%,革兰阴性菌199674株占76.2%。常见的分离菌依次为大肠埃希菌(46.7%)、屎肠球菌(10.4%)、肺炎克雷伯菌(9.8%)、粪肠球菌(8.7%)、奇异变形杆菌(3.5%)、铜绿假单胞菌(3.4%)、无乳链球菌(2.6%)和阴沟肠杆菌(2.1%)。上述细菌主要分离自住院患者,女性多见于男性,成人多见于儿童。大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌中产超广谱β内酰胺酶(ESBL)菌株分别占53.2%、52.8%和37.0%。耐碳青霉烯类的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌中检出率分别为1.7%、18.5%、16.4%和40.3%。粪肠球菌对氨苄西林、呋喃妥因、利奈唑胺、万古霉素、替考拉宁和磷霉素的耐药率<10%,屎肠球菌对氨苄西林、左氧氟沙星、红霉素的耐药率>90%,对万古霉素、利奈唑胺和替考拉宁的耐药率<2%。ICU住院患者分离的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌对大部分抗菌药物的耐药率明显高于门诊患者和非ICU住院患者。结论尿液标本临床分离菌主要以大肠埃希菌、肠球菌和肺炎克雷伯菌为主,不同人群尿液标本中分离的细菌种类和耐药性不尽相同,应重视细菌耐药监测,减少抗菌药物的不合理使用。