Increases in the Macrolide Resistance of Mycoplasma genitalium and the Emergence of the A2058T Mutation in the 23S rRNA Gene: Clonal Spread?

The management of Mycoplasma genitalium sexually transmitted infection (STI) is hindered by increasing resistance to the recommended antibiotics, macrolides and quinolones, worldwide. In Gipuzkoa (Basque Country, Spain), macrolide and quinolone resistance rates in 2014−2018 were reported as <20% and <10%, respectively. The aims of this study were to compare these rates with those in 2019−2021 and analyse the genetic and epidemiological features of the strains and cases associated with striking changes in the resistance trends. Resistance to macrolides (n = 1019) and quinolones (n = 958) was studied, analysing mutations in 23S rRNA and parC/gyrA genes, respectively. The rate of macrolide resistance increased from 17.3% in 2014−2018 to 32.1% in 2019−2021, as much in the more prevalent A2058/2059G mutations (16.6−27.8%) as in the emergent A2058T mutations (0.5−4.1%) but with differences in the odds ratios and the relative risk increase between A2058T and A2058/2059G mutations. MG191 adhesin and MG309 lipoprotein of the 27 emergent strains detected with A2058T mutations were amplified, sequenced, and typed using phylogenetic and variable number tandem repeat analysis, respectively. Genetic clonal spread was ruled out, but most of the A2058T cases were men who had sex with men (24/27) with a history of STI and antibiotic treatments (19/27). No changes were observed in quinolone resistance trends, but the rate of resistance to both antibiotics rose from 2.9% to 8.3%, especially in cases with A2058T mutations. The genetic characterisation of strains and epidemiological surveillance of cases are needed to detect populations at increased risk of treatment failure in this infection.

Transmission of Antibiotic Resistant Bacteria and Genes: Unveiling the Jigsaw Pieces of a One Health Problem.

Antimicrobial Resistance is one of the major Global Health challenges of the twenty-first century, and one of the World Health Organization's (WHO) top ten global health threats. The evolution of antibiotic resistance among bacterial pathogens requires urgent concerted global efforts under a One Health approach integrating human, animal, and environmental surveillance data. This is crucial to develop efficient control strategies and counteract the spread of multidrug-resistant pathogens. The studies in this Special Issue have evidenced the hidden role of less common species, unusual clones or unexplored niches in the dissemination of antimicrobial resistance between different hosts. They reinforce the need for large-scale surveillance studies tracing and tracking both antibiotic resistance and metal tolerance in different bacterial species.

Global antimicrobial resistance: a complex and dire threat with few definite answers.

Alors que divers organismes internationaux ont récemment proposé des plans pour la création de systèmes de surveillance de la résistance antimicrobienne (RAM), la plupart des PRMF ne disposent pas des infrastructures et des ressources pour le faire efficacement. La RAM est donc un problème majeur d'équité en matière de santé, mais aussi un exemple de la connexion dans notre monde unique: les populations les plus à risque disposent des mécanismes de surveillance et de confinement les plus médiocres; dans le même temps, la migration mondiale, les voyages et le commerce nous rendent tous vulnérables. Les mesures que nous utilisons actuellement ne capturent pas de manière significative l'impact potentiel de la RAM aux niveaux sanitaire, économique et sociétal plus large. La surveillance mondiale de la RAM devrait inclure une surveillance étroite de l'utilisation d'antibiotiques chez les animaux, ainsi que les concentrations de divers produits chimiques libérés dans l'environnement. En fin de compte, les efforts coordonnés de divers scientifiques et parties prenantes, dans diverses disciplines et dans le monde, sont essentiels pour relever les défis pressants de la RAM mondiale croissante.

Pharmacokinetic/pharmacodynamic analysis as a tool for surveillance of the activity of antimicrobials against Pseudomonas aeruginosa strains isolated in critically ill patients.

INTRODUCTION: To evaluate the changes in the susceptibility of Pseudomonas aeruginosa over time (2000-2017) against antimicrobials used in an intensive care unit of a Spanish tertiary hospital, and to compare them with the antimicrobial activity considering theoretical pharmacokinetic/pharmacodynamic (PK/PD) criteria. The influence of the method for handling duplicate isolates to quantify susceptibility rates was also evaluated. METHODS: The susceptibility was studied considering the Clinical and Laboratory Standards Institute (CLSI) breakpoints. Monte Carlo simulations were conducted to calculate the cumulative fraction of response (CFR). Linear regression analysis was applied to determine the trends in susceptibility and in the CFR. RESULTS: A significant decrease in the susceptibility to gentamicin and imipenem was observed, and more recently the highest percentages of susceptible strains were found for amikacin, cephalosporins and piperacillin/tazobactam (>80%). The probability of success of an empiric treatment or CFR for most of the evaluated antimicrobials was lower than 70% during the last two-year period. Only meropenem provided high probabilities (>90%) to achieve the PK/PD target. Cephalosporins provided moderate probabilities (>80%) although for ceftazidime, the highest dose (2g/8h) was required. Moreover, a significant decrease in the CFR trend for ciprofloxacin, imipenem and levofloxacin was observed. CONCLUSIONS: Both susceptibility rates and CFR values have to be considered together to optimize the antimicrobial dose regimen for clinical making-decisions. They are complementary tools and, they should be used jointly in surveillance programmes. In fact, susceptibility data are not always useful to detect changes in the CFR. No relevant differences were observed among the methods for handling repeated isolates.

Surveillance of antibiotic resistance in the bacterial strains isolated from the First Hospital of Qiqihar in 2015 / 中国感染与化疗杂志

Objective To investigate the distribution and antibiotic resistance profile of clinical isolates in the First Hospital of Qiqihar during 2015.Methods Antimicrobial susceptibility test was carried out according to a unified protocol using automated system from January 1,2015 to December 31,2015.The results were analyzed with WHONET 5.6 software according to the 2014 breakpoints of Clinical and Laboratory Standards Institute.Results A total of 5 162 clinical isolates were collected,of which 28.1％ (1 450/5 162) were gram-positive cocci and 71.9％ (3 712/5 162) were gram-negative bacilli.About 36.5％ (255/698) ofS.aureus isolates and 81.4％ (180/221) of coagulase negative Staphylococcus isolates were resistant to methicillin.No S.aureus and coagulase negative Staphylococcus isolate were found resistant to vancomycin or linezolid.Enterococcus isolates showed low resistance to vancomycin and linezolid.One strain of E.faecium was found resistant to vancomycin.ESBLs were produced in 39.9％ (298/747) ofE.coli,26.1％ (294/1 127) ofKlebsiella spp.,and 15.6％ (12/77) ofP mirabilis strains.The Enterobacteriaceae strains were less resistant to imipenem,beta-lactam/beta-lactamase inhibitor combination and amikacin.About 36.6％ (163 / 445) of A.baumannii isolates and 1.8％ (13/715) of P.aeruginosa isolates were extensively drug-resistant strains.Conclusions Antibiotic resistance poses a serious threat to clinical practice,to which more attention should be paid.Clinical microbiology lab should make more efforts to provide better support to clinical therapy.

Surveillance and drug resistance analysis of Salmonella in Guangdong province in 2015 / 中华微生物学和免疫学杂志

Objective To analyze the serotype distribution and antibiotic resistance characteristics of Salmonella strains isolated in Guangdong province for better understanding the condition of Salmonella infection in patients with diarrhea.Methods Fecal samples collected from patients with diarrhea in Guangdong province were used to isolate Salmonella strains.Biochemical analysis was performed to identify these isolated strains.Serotyping and antimicrobial susceptibility testing were carried out for further analysis of the isolated Salmonella strains.Results The rate of Salmonella infection was 7.64％in 2015, and the male to female patient ratio was 1.52∶1.A total of 2 377 patients of all age groups were positive for Salmonella infection and the patients aged 0-6 years accounted for 81.74％.The isolation rate of Salmonella strains in the summer and autumn was higher than that in the winter and spring (10.73％ vs 4.24％;X2=463.77, P<0.01).The Salmonella isolation rates in different areas were as follows: 16.82％ in Zhuhai, 15.85％ in Heyuan, 11.81％ in Yangjiang, 10.68％ in Jiangmen, 8.49％ in Zhongshan, 8.07％ in Maoming, 8.05％ in Jieyang, 7.35％ in Shaoguan, 6.97％ in Foshan, 6.03％ in Dongguan, 5.48％ in Guangzhou and 0.00％ in Zhanjiang.And the differences between different regions were statistically significant (X2=367.67, P<0.01).The 2 377 isolated Salmonella strains were classified into 108 serotypes except for oneSalmonella strain that could not be classified.The top four predominant serotypes were 4,5,12:i:-, Salmonella enteritidis,Salmonella stanley and Salmonella typhimurium.Most Salmonella strains were sensitive to imipenem, azithromycin, ceftazidime, cefotaxime and trimethoprim/sulfamethoxazole, but multidrug resistance was common among those strains.Conclusion Salmonella serotypes of 4,5,12:i:-and Salmonella enteritidis are the predominant pathogens causing human Salmonella infections in Guangdong province.Ceftazidime and cefotaximeare are preferred in the treatment of Salmonella infections.Surveillance for drug resistance in Salmonella should be strengthened as multidrug resistant strains have become a serious problem in Guangdong province.

Surveillance of bacterial resistance in the Second Hospital of Hebei Medical University from 2015 to 2016 / 中国感染与化疗杂志

Objective To investigate the antibiotic resistance in clinical isolates in the Second Hospital of Hebei Medical University from 2015 to 2016.Methods A total of 16 292 strains of non-duplicate bacterial strains were collected.The isolates were subjected to identification and antimicrobial susceptibility testing on VITEK 2-Compact system.The data were processed and analyzed using WHONET 5.6 software.Results Specifically,7 961 and 8 331 strains of pathogens were collected in 2015,2016,respectively.Gram-negative bacteria accounted for 62.0％ in 2015 and 66.9％ in 2016,respectively.The top five pathogens isolated in these two years were still Klebsiella pneumoniae,Escherichia coli,Acinetobacter baumannii,Pseudomonas aeruginosa,and Staphylococcus aureus.The proportion of K.pneumoniae increased to the first place in 2016 which accounted for 16.1％.Coagulase negative Staphylococcus in blood samples decreased from 42.6％ in 2015 to 30.0％ in 2016.Vancomycin resistant strains were not found in Staphylococcus.In 2015 and 2016,the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) was 56.2％ and 51.3％,respectively.The prevalence of methicillinresistant coagulase negative Staphylococcus (MRCNS)was 79.3％ and 63.1％,respectively.Enterococcus faecalis and Enterococcus faecium accounted for 25.2％ and 73.2％ respectively in the 911 strains of Enterococcus.In 2015 and 2016,3.1％ and 2.9％ of the E.faecium strains were resistant to vancomycin,respectively.In 2016,the prevalence of carbapenemresistant strains increased in K.pneumoniae,E.coli and E.cloacae.K.pneumoniae showed increasing resistance rate to all the antimicrobial agents tested except for gentamicin and amikacin.The percentage of the K.pneumoniae strains resistant to imipenem and meropenem increased from 19.3％,18.5％ in 2015 to 24.2％,23.1％,respectively.A.baumannii isolates were still highly resistant to the commonly used antibiotics in these two years,but relatively susceptible to polymyxin B,tigecycline,cefoperazone-sulbactam and minocycline (＜30％ resistant).P.aeruginosa isolates showed lower resistance rate to amikacin (11.7％),cefoperazonesulbactam (15.5％),piperacillin-tazobactam (18.7％),ceftazidime (20.1％),cefepime (21.9％).P.aeruginosa presented a trend of declining resistance to all the antimicrobial agents tested from 2015 to 2016,except aztreonam,to which the resistant P.aeruginosa strains increased from 27.0％ in 2015 to 34.7％ in 2016.Conclusions The antimicrobial susceptibility profile of clinical bacterial isolates has been changing constantly.We need to adopt effective infection prevention and control measures in hospital and further standardize and control the use of antibacterial agents.

Real-time quantitative PCR assay with Taqman(®) probe for rapid detection of MCR-1 plasmid-mediated colistin resistance.

Here we report the development of two rapid real-time quantitative PCR assays with TaqMan(®) probes to detect the MCR-1 plasmid-mediated colistin resistance gene from bacterial isolates and faecal samples from chickens. Specificity and sensitivity of the assay were 100% on bacterial isolates including 18 colistin-resistant isolates carrying the mcr-1 gene (six Klebsiella pneumoniae and 12 Escherichia coli) with a calibration curve that was linear from 10(1) to 10(8) DNA copies. Five out of 833 faecal samples from chickens from Algeria were positive, from which three E. coli strains were isolated and confirmed to harbour the mcr-1 gene by standard PCR and sequencing.

A novel Direct MIC-gradient Strip Method to screen for antibiotic-resistant faecal Enterobacteriaceae.

A novel method to detect resistant faecal Enterobacteriaceae was developed by applying MIC-gradient strips directly onto agar plates inoculated with faeces. The method provided the susceptibility pattern (MICs) of the dominant bacterial population directly on the plates and also detected smaller resistant subpopulations with a sensitivity of 1/10(5).

CHINET 2012 surveillance of antibiotic resistance in Klebsiella spp .in China / 中国感染与化疗杂志

Objective To investigate the antimicrobial resistance of clinical strains of K lebsiella spp .isolated from 15 hospitals in China CHINET during 2012 .Methods Kirby-Bauer method and automatic microbiology analysis system were employed to study the antimicrobial resistance . WHONET 5 .6 software was applied for data analysis according to Clinical and Laboratory Standards Institute (CLSI) 2012 breakpoints .Results A total of 9 621 clinical K lebsiella isolates were analyzed ,including 8 772 strains of K . pneumoniae and 804 strains of K . oxytoca . About 54 .9% (5 285/9 621) of the K lebsiella strains were isolated from sputum ,and 16 .3% (1 564/9 621) were isolated from pediatric patients .Antimicrobial susceptibility testing showed that about 8 .9% ,10 .8% and 12 .9% of the strains were resistant to imipenem ,meropenem and ertapenem ,respectively .About 14 .1% and 17 .0% of the strains were resistant to piperacillin-tazobactam and cefoperazone-sulbactam , respectively . Carbapenem-resistant K lebsiella strains were identified from all the 15 hospitals ,including 945 strains of K .pneumoniae and 45 strains of K .oxytoca ,which were resistant to either imipenem ,meropenem or ertapenem .Conclusions The Klebsiella isolates collected from 15 hospitals in China during 2012 are relatively sensitive to carbapenems ,cefoperazone-sulbactam and piperacillin-tazobactam .The prevalence of carbapenem-resistant strains is still increasing in China ,about 10 .3% in 2012 ,and relatively higher in Eastern China .More efforts should be made to control the superbug .

Drug resistance monitoring of Enterococcus faecalis and Enterococcus faecium in the hospital from 2009 to 2013 / 国际检验医学杂志

Objective To investigate the antimicrobial resistance of E.faecalis and E.faecium isolated from the Hospital from 2009 to 2013.Methods Minimum inhibitory concentration method was used for antimicrobial susceptibility test of the clinical iso-lates.Results were judged according to Clinical and Laboratory Standards Institute′s 2013 version of criterias.Results A total of 819 nonduplicated E.Faecalis and 726 nonduplicate E.faecium isolates were collected.The strains were still highly susceptible to linezolid and vancomycin,to which the drug-resistance rates were both less than 1.5%.The prevalence of vancomycin-resistant E. faecalis and E.faecium was 0.1% and 1.5%,respectively.The ratio of E.faecalis resistant to ampicillin,penicilin and nitrofuran-toin was 4.3%,1.6% and 1.6%,respectively.More than 87% E.faecium strains were resistant to ampicillin and penicillin,and the E.faecium strains were more resistant to most drugs tested than E.faecalis .Conclusion There was an obvious difference of anti-biotic resistance beween E.Faecalis and E.Faecium isolates.Therefore,Continuous monitoring the drug resistance is helpful to guide the clinical rational drug use.

The resistance surveillance of Enterococcus faecalis and Enterococcus faecium from the First Affiliated Hospital of Chongqing Medical University between 2009 and 2012 / 国际检验医学杂志

Objective To investigate the antimicrobial resistance of Enterococcus f aecalis and Enterococcus f aecium isolated from the First Affiliated Hospital of Chongqing Medical University between 2009 and 2012 .Methods Antimicrobial susceptibility testing was carried out according to the unified protocol .The dates were analyzed by WHONET 5 .6 software according to clinical and laboratory standards institute(CLSI) of 2012 .Results A total of 783 non-repetitive Enterococcus f aecalis and 664 non-repeti-tive Enterococcus f aecium isolates were collected .The strains were still highly susceptible to linezolid and vancomycin .The resist-ance rates were all less than 2 .0% .The resistance rates of vancomycin to Enterococcus f aecalis and Enterococcus f aecium were 0 .1% and 1 .4% ,respectively .The percentage of Enterococcus f aecalis resistant to ampicillin ,penicilin and nitrofurantoin were 5 .7% ,2 .6% and 2 .2% ,respectively .About 32 .9% of Enterococcus f aecalis isolates were resistant to gentamicin .The resistance rates of ampicillin and penicillin to Enterococcus f aecium were more than 90 .0% .Conclusion Enterococcus f aecalis is main En-terococcus in the First Affiliated Hospital of Chongqing Medical University .There is an obvious difference between the antibiotic re-sistance of the Enterococcus f aecalis and Enterococcus f aecium .So ,monitoring drug resistance of the Enterococcus shows great sig-nificance to the clinical treatment .

Diversity of ß-lactam resistance mechanisms in cystic fibrosis isolates of Pseudomonas aeruginosa: a French multicentre study.

OBJECTIVES: To investigate the resistance mechanisms of ß-lactam-resistant Pseudomonas aeruginosa isolated from cystic fibrosis (CF) patients in France. METHODS: Two-hundred-and-four P. aeruginosa CF isolates were collected in 10 French university hospitals in 2007. Their susceptibility to 14 antibiotics and their resistance mechanisms to ß-lactams were investigated. Their ß-lactamase contents were characterized by isoelectric focusing, PCR and enzymatic assays. Expression levels of efflux pumps and the intrinsic ß-lactamase AmpC were quantified by reverse transcription real-time quantitative PCR. Genotyping was performed using multiple-locus variable number of tandem repeats analysis (MLVA). The oprD genes were sequenced and compared with those of reference P. aeruginosa strains. To assess deficient OprD production, western blotting experiments were carried out on outer membrane preparations. RESULTS: MLVA typing discriminated 131 genotypes and 47 clusters. One-hundred-and-twenty-four isolates (60.8%) displayed a susceptible phenotype to ß-lactams according to EUCAST breakpoints. In the 80 remaining isolates, resistance to ß-lactams resulted from derepression of intrinsic cephalosporinase AmpC (61.3%) and/or acquisition of secondary ß-lactamases (13.8%). Efflux pumps were up-regulated in 88.8% of isolates and porin OprD was lost in 53.8% of isolates due to frameshifting or nonsense mutations in the oprD gene. CONCLUSIONS: ß-Lactam resistance rates are quite high in CF strains of P. aeruginosa isolated in France and not really different from those reported for nosocomial strains. Development of ß-lactam resistance is correlated with patient age. It results from intrinsic mechanisms sequentially accumulated by bacteria isolated from patients who have undergone repeated courses of chemotherapy.