Associations Between Anti‐Microbial Resistance Phenotypes,Anti‐Microbial Resistance Genotypes and Virulence Genes of Escherichia coli Isolates from Pakistan and China

The objective of this study was to determine the association between phenotypic resistance, genotypic resistance and virulence genes of Escherichia coli isolates in Jiangsu province, China and Punjab province Pakistan. A total of 62 E. coli isolates were characterized for phenotypic resistance, genotypic resistance and virulence factor genes. The anti‐microbial resistance phenotype and genotypes in relation to virulence factor genes were assessed by statistical analysis. Of 20 tested virulence genes, twelve were found and eight were not found in any isolates. sitA and TspE4C2 were the most prevalent virulence genes. Of the 13 anti‐microbial agents tested, resistance to ampicillin, sulphonamide and tetracycline was the most frequent. All isolates were multiresistant, and 74% were resistant to trimethoprim and sulphamethaxazole. Phenotypically, tetracycline‐, cefotaxime‐ and trimethoprim‐resistant isolates had increased virulence factors as compared with susceptible isolates. Genotypically, resistant genes Tem, ctx‐M, Tet, Sul 1, dhfr1, Cat2 and flo‐R showed the association with the virulence genes. Almost all classes of anti‐microbial‐resistant genes have a high association with virulence. Resistant isolates have more virulent genes than the susceptible isolates.     

Population structure and antimicrobial resistance traits of avian‐origin mcr‐1‐positive Escherichia coli in Eastern China, 2015 to 2017

Recent emergence of mcr‐1‐positive Escherichia coli (MCRPEC) is causing serious concern around the world. Due to poultry‐origin E. coli holding zoonotic potential, the improved understandings of MCRPEC population structure and antimicrobial resistance are critical to public health purposes. This study provided novel insights into the molecular epidemiology of avian‐origin MCRPEC. For the mcr genes prevalence study, we analysed 1,360 E. coli recovered from avian colibacillosis in eastern China from 2015 to 2017. The mcr‐1 was present in 172 (12.6%) E. coli isolates. For all of MCRPEC isolates, MICs of colistin were ≥4 mg/L. Avian‐origin MCRPEC was widely distributed throughout phylogroups A, B1, B2, D, and F. Moreover, those isolates were assigned to 52 unique STs, such as ST48, ST117, ST131, and ST648, suggesting substantial horizontal dissemination of mcr‐1 gene through avian‐origin E. coli populations. The susceptibility of MCRPEC isolates was tested with 26 antimicrobial agents from 16 antimicrobial categories. There were high resistance rates of MCRPEC isolates against the clinically used antibiotics. All MCRPEC isolates in this study presented the multidrug‐resistant (MDR) trait were even considered as extensively drug‐resistant (XDR) strains. Resistance genotypes and plasmid replicon profiling showed that a majority of MCRPEC isolates contained plasmid‐mediated resistance genes and exhibited the co‐existence of mcr‐1 with ESBLs and pAmpCs genes. Furthermore, the overlapped distribution of ST types and resistance gene contents was detected among MCRPEC isolates from humans and poultry. Besides mcr‐1, our findings highlighted a significant prevalence of plasmid‐mediated resistance genes among avian‐origin MCRPEC isolates.     

Nitrofurantoin: the return of an old friend in the wake of growing resistance

OBJECTIVE

To re‐evaluate the first‐ and second‐line therapies for treating uncomplicated urinary tract infection (UTI), as although fluoroquinolones are commonly used for this purpose, its level of use is thought to be inappropriately excessive and will eventually have a detrimental impact; thus we hypothesise that nitrofurantoin might be the best choice for this indication, due to its low frequency of use and its high susceptibility rate in common UTI pathogens.

MATERIALS AND METHODS

We retrospectively analysed antimicrobial susceptibility patterns of urinary isolates from 2003 to 2007, taken from a community‐based institutional hospital in Brooklyn, NY, USA.

RESULTS

In all, 10 417 cultures grew Escherichia coli from 2003 to 2007. Overall, from 2003 to 2007, 95.6% of E. coli urine isolates were susceptible to nitrofurantoin, with an average 2.3% resistance rate. By contrast, E. coli uropathogens had a mean 75.6% and 75.9% susceptibility and 24.2% and 24% resistance rate to both ciprofloxacin and levofloxacin, respectively. Co‐trimoxazole (trimethoprim/sulfamethoxazole; ‘TMP/SMX’) had a mean 29% resistance rate to E. coli over the same 5‐year period.

CONCLUSIONS

We consider that nitrofurantoin is a good fluoroquinolone‐sparing alternative to co‐trimoxazole; this study shows that nitrofurantoin is bactericidal to a mean of 95% of E. coli UTIs. Nitrofurantoin also has a resistance rate of 2.3%, by contrast to the quinolones (ciprofloxacin and levofloxacin), with resistant rates of ≈24%, and Co‐trimoxazole, with a resistant rate of 29%. Nitrofurantoin is an acceptable treatment for uncomplicated UTIs and should now be considered the first‐line treatment. A reconsideration of UTI treatment guidelines might now be appropriate.     

Antimicrobial Resistance of F4+ Escherichia Coli Isolated from Swine in Italy

Four‐hundred and forty‐two F4+ pathogenic Escherichia coli were isolated in a period of 10 years (2002–2011), from pigs that were suffering from diarrhoea belonging to Italian swine herds. The strains were analysed for their susceptibility to 12 antimicrobials using the disc diffusion method. During the study period, a statistically significant proportion of isolates resistant to enrofloxacin (14.5–89.3%), marbofloxacin (5.4–60.7%), flumequine (49.1–92.9%), danofloxacin (21.6–80%), florfenicol (9.8–64.3%), thiamphenicol (50–92%) and cefquinome (3.8–44%) was recorded. An increase in resistance (not statistically significant) to gentamicin (63.6–85.7%), apramycin (61.8–82.1%), trimethoprim‐sulphamethoxazole (75–89.3%), tetracycline (97–100%) and erythromycin (92.4–100%) was also observed. Based on antimicrobial multiresistance, the strains were collected into three groups: I. resistant to 2–5 antimicrobials; II. resistant to 6–8 antimicrobials; III. resistant to 9–12 antimicrobials. The number of isolates belonging to the first group showed a statistically significant decrease (P < 0.05; R² = 0.896; r = −0.9608), while the isolates belonging to the second and third groups showed a statistically significant increase in resistance (P < 0.05; R² = 0.753; r = 0.8890 and P < 0.05; R² = 0.727; r = 0.8701, respectively) over the period of study. The results of this study suggest the need for continued monitoring of the development of resistance.     

Identification and molecular characterization of Staphylococcus aureus and multi‐drug resistant MRSA from monkey faeces in China

Staphylococcus aureus is a commensal bacterium and an important opportunistic pathogen in humans and animals. The increase in multi‐drug resistant (MDR) strains of S. aureus is a growing concern due to their impact on animal health and potential for zoonotic transmission. Increasing evidence has shown that MRSA could be transmitted by faeces. The present study determined the prevalence, antibiotic resistance profile and genotypic characteristics of S. aureus isolated from monkey faecal samples in China. Thirty‐eight out of 145 (26.21%) macaque faecal samples were S. aureus positive, which eight (5.5%) isolates were identified as MRSA. Antimicrobial susceptibility tests showed that most of the S. aureus isolates were resistant to tetracycline (TE, 44.74%), followed by penicillin (P, 21.05%), cefoxitin (FOX, 21.05%) and ciprofloxacin (CIP, 18.42%). The predominant spa types were t13638 (44.74%) and t189 (13.16%), which are reported to be closely associated with human infections in China. All MRSA isolates belonged to the SCCmecV type, which six of MRSA isolates were ST3268, while the other two isolates belonged to ST4981. This study for the first time describes the prevalence of S. aureus and MRSA in monkey faeces in China, indicating that faeces could be a potential factor of transmitting S. aureus between humans and monkeys.     

Wild griffon vultures (Gyps fulvus) fed at supplementary feeding stations: Potential carriers of pig pathogens and pig‐derived antimicrobial resistance?

The carriage of two important pathogens of pigs, that is enterotoxigenic Escherichia coli (ETEC) and Clostridioides difficile, was investigated in 104 cloacal samples from wild griffon vultures (Gyps fulvus) fed on pig carcasses at supplementary feeding stations (SFS), along with their level of antimicrobial resistance (AMR). E. coli was isolated from 90 (86.5%) samples, but no ETEC was detected, likely because ETEC fimbriae confer the species specificity of the pathogen. Resistance to at least one antimicrobial agent was detected in 89.9% of E. coli isolates, with AMR levels being extremely high (>70%) for tetracycline and streptomycin and very high (>50%) for ampicillin and sulfamethoxazole–trimethoprim. Resistance to other critically important antimicrobials such as colistin and extended‐spectrum cephalosporins was 2.2% and 1.1%, respectively, and was encoded by the mcr‐1 and bla_SHV‐12 genes. Multidrug resistance was displayed by 80% of the resistant E. coli, and bla_SHV‐12 gene shared plasmid with other AMR genes. In general, resistance patterns in E. coli from vultures mirrored those found in pigs. Clostridioides difficile was detected in three samples (2.9%); two of them belonged to PCR ribotype 078 and one to PCR ribotype 126, both commonly found in pigs. All C. difficile isolates were characterized by a moderate‐to‐high level of resistance to fluoroquinolones and macrolides but susceptible to metronidazole or vancomycin, similar to what is usually found in C. difficile isolates from pigs. Thus, vultures may contribute somewhat to the environmental dissemination of some pig pathogens through their acquisition from pig carcasses and, more importantly, of AMR for antibiotics of critical importance for humans. However, the role of vultures would likely be much lesser than that of disposing pig carcasses at the SFS. The monitoring of AMR, and particularly of colistin‐resistant and ESBL‐producing E. coli, should be considered in pig farms used as sources of carcasses for SFS.     

Diversified sources for human infections by Salmonella enterica serovar newport

Salmonella enterica Newport (S. Newport), with phylogenetic diversity feature, contributes to significant public health concerns. Our previous study suggested that S. Newport from multiple animal‐borne routes, with distinct antibiotic resistant pattern, might transmit to human. However, their genetic information was lacking. As a complement to the earlier finding, we investigate the relationship between each other among the hosts, sources, genotype and antibiotic resistance in S. Newport. We used the multilocus sequence typing (MLST) in conjunction with minimum inhibitory concentration of 16 antibiotics of globally sampled 1842 S. Newport strains, including 282 newly contributed Chinese strains, to evaluate this association. Our analysis reveals that sequence types (STs) are significantly associated with different host sources, including livestock (ST45), birds (ST5), contaminated water and soil (ST118), reptiles (ST46) and seafood (ST31). Importantly, ST45 contained most of (344/553) the multi‐drug resistance (MDR) strains, which were believed to be responsible for human MDR bacterial infections. Chinese isolates were detected to form two unique lineages of avian (ST808 group) and freshwater animal (ST2364 group) origin. Taken together, genotyping information of S. Newport could serve to improve Salmonella source‐originated diagnostics and guide better selection of antibiotic therapy against Salmonella infections.     

Spectrum and drug resistance of pathogens from patients with burns

Microbial infection is an obstacle of burn treatment. However, little is known on what types of microbial infection dominate in the burn center and how the dynamic change of those microorganisms occurs during the past several years in China. We conducted a retrospective study of nosocomial infection (NI) in a large burn center to analyze the spectrum and antimicrobial resistance of microbial isolates from January 2003 to December 2010. We studied 989 isolates from 677 patients who had signs and symptoms of infection 48 h after admission. The number of NIs per 100 admissions was 10.9. The commonest isolates were Pseudomonas aeruginosa (23.1%), Staphylococcus aureus (18.7%), and Candida (11.4%). The result indicated that the numbers of patients with Acinetobacter sp. infection increased (P = 0.004), but with Proteus mirabilis infection decreased (P = 0.004). The isolated Acinetobacter sp. and P. aeruginosa were consistently highly resistant to almost all antibiotics tested. Notably, more frequent Acinetobacter sp. isolates appeared to be resistant to amikacin, gentamicin, tobramycin, ceftazidim, piperacillin, tazobactam, levofloxacin, and ciprofloxacin and more frequent Escherichia coli isolates were resistant to ceftazidime and aztreonam at the late time period although the P. aeruginosa and E. coli isolates were sensitive to less used ciprofloxacin and piperacillin/tazobactam. The increased rates of drug-resistant isolates in the later period might be associated with regular prophylactic therapy with antibiotics.     

Mutations in 23S rRNA and ribosomal protein L4 account for resistance in Chlamydia trachomatis strains selected in vitro by macrolide passage

Thirteen strains of Chlamydia trachomatis were exposed to subinhibitory concentrations of erythromycin (0.5 μg ml^?1), azithromycin (0.5 μg ml^?1) and josamycin (0.04 μg ml^?1) to select macrolide‐resistant mutants with serial passages. The C. trachomatis mutants presented with low‐level resistance to erythromycin, azithromycin and josamycin for which a 16‐fold increase, a 16‐fold increase and an 8‐fold increase respectively in the minimal inhibitory concentration (MICs) for the mutant strains compared with the MIC for the susceptible strains were found. The results of chemosensitivity showed that josamycin had the highest susceptibility rate compared with erythromycin and azithromycin in the treatment of C. trachomatis. The ribosomal protein L4 and 23S rRNA genes of the susceptible and resistant strains of C. trachomatis were partially sequenced. A double mutation was found in ribosomal protein L4 of the mutants, leading to Pro109(CCG)→Leu(CTG), and Pro151(CCG)→Ala(GCC) (Escherichia coli numbering) in the corresponding protein, but these mutations were also found in parent strains. An investigation into the sequences of 23S rRNAs in the mutants revealed point mutations of A2057G, A2059G and T2611C (E. coli numbering). These results suggest that point mutations located in 23S rRNA were associated with macrolide resistance in C. trachomatis.     

The changing pattern of antimicrobial resistance within 42,033 Escherichia coli isolates from nosocomial, community and urology patient-specific urinary tract infections, Dublin, 1999-2009

Study Type – Therapy (practice patterns cohort) Level of Evidence not applicable What's known on the subject? and What does the study add? Epidemiological and resistance patterns of bacterial pathogens in urinary tract infections show large inter‐regional variability, and rates of bacterial resistance are continually changing due to different regional antibiotic treatment regime. In Ireland and the UK, trimethoprim or nitrofurantoin is usually recommended for empirical treatment of uncomplicated cystitis in the community whilst parenteral cephalosporins, aminoglycosides, quinolones and co‐amoxyclav are reserved for complicated UTIs. Neither penicillins nor trimethoprim represent suitable empirical antimicrobial agents for UTI in this study population. The high rate of ciprofloxacin resistance in encountered is suggestive of an over‐reliance on this agent in this population and with resistance rates approaching 30%, empirical use of quinolones for urology patients is inadvisable. E. coli UTIs have remained extremely sensitive to nitrofurantoin across all three patient sample groups in this population and the resistance rate has not changed significantly over the eleven‐year study period.

OBJECTIVE

• ? To investigate the changing pattern of antimicrobial resistance in Escherichia coli urinary tract infection over an eleven year period, and to determine whether E. coli antibiotic resistance rates vary depending on whether the UTI represents a nosocomial, community acquired or urology patient specific infection.

PATIENT AND METHODS

• ? A retrospective analysis of the 42 033 E. coli urine isolates from the 11‐year period 1999–2009 in a single Dublin teaching hospital was performed.
• ? WHONET^TM software was used to analyse the changing pattern of sensitivity and resistance of E. coli to commonly used antibiotics over the study period.
• ? The origins of the urine samples were stratified into three groups: inpatients with nosocomial UTIs; urine originating from the emergency department and general practice (community UTIs); and UTIs in urology patients.

RESULTS

• ? Urinary tract infections in the urology patient population demonstrate higher antibiotic resistance rates than nosocomial or community UTIs.
• ? There were significant trends of increasing resistance over the 11‐year period for ampicillin, trimethoprim, gentamicin and ciprofloxacin, and significant differences in co‐amoxyclav, gentamicin, nitrofurantion and ciprofloxacin resistance rates depending on the sample origin.
• ? Ampicillin and trimethoprim were the least active agents against E. coli, with total 11‐year resistance rates of 58.3 and 33.8%, respectively.
• ? The overall gentamicin resistance rate was 3.4% and is climbing at a rate of 0.7% per year (P < 0.001). Within the urology patient population the resistance rate was 6.4%.
• ? Ciprofloxacin resistance approaches 20% in the nosocomial UTI population and approaches 30% in the urology population; however, it remains a reasonable empirical antibiotic choice in this community, with an 11‐year resistance rate of 10.6%.

CONCLUSIONS

• ? E. coli remains the commonest infecting uropathogen in the community and hospital setting with its incidence climbing from 50 to 60% of UTIs over the 11‐year period.
• ? Neither penicillins nor trimethoprim represent suitable empirical antimicrobials for UTI and ciprofloxacin resistance in this Dublin‐based study renders it unsuitable empirical therapy for nosocomial UTIs and UTIs in the urology population.
• ? The dramatic 11‐year rate increase in gentamicin resistance is of paramount concern.

     

Single dose 1 g ceftriaxone for urogenital and pharyngeal infection caused by Neisseria gonorrhoeae

Objectives: To evaluate the efficacy of 1 g ceftriaxone in the treatment of urethritis, cervicitis and pharyngeal infection caused by Neisseria gonorrhoeae (N. gonorrhoeae) including the oral cephem‐resistant strain with chimera penicillin‐binding protein 2 (PBP‐2) (cefozopran‐resistant N. gonorrhoeae, CZRNG). Methods: From September 2004 to November 2006, 67 patients (27 male and 40 female) who had genital infection and/or pharyngeal infection caused by N. gonorrhoeae were enrolled in this study at five participating centers in Japan. To detect the chimera PBP‐2 gene, polymerase chain reaction (PCR) was performed using established primers against the altered penA of CZRNG isolates. All patients received a single 1 g dose of ceftriaxone. Efficacy was evaluated only in those who returned for examination and culture for N. gonorrhoeae between 3 and 14 days after the treatment. Results: CZRNG isolates detected by PCR accounted for 41.7% (20/48) of urogenital infections and 60.0% (15/25) of pharyngeal infections in the treatment efficacy evaluable cases. 37 of 39 CZRNG isolates (94.9%) were multi‐drug resistant isolates that had simultaneous resistance to penicillin, tetracycline, and ciprofloxacin. Nineteen patients had N. gonorrhoeae isolates in the urogenital area and pharynx simultaneously. Ceftriaxone treatment eradicated all N. gonorrhoeae isolates from 48 patients with genitourinary infection and 25 patients with pharyngeal infection. Conclusions: We report for the first time that ceftriaxone is effective in patients with gonococcal urethritis, cervicitis, and pharyngeal infection caused by CZRNG that has chimera PBP‐2.     

Virulent and multidrug‐resistant Klebsiella pneumoniae from clinical samples in Balochistan

Klebsiella pneumoniae is an important pathogen causing hospital‐acquired infections in human beings. Samples from suspected patients of K pneumoniae associated with respiratory and urinary tract infections were collected at Bolan Medical Complex, Quetta, Balochistan. Clinical samples (n = 107) of urine and sputum were collected and processed for K pneumoniae isolation using selective culture media. Initially, 30 of 107 isolates resembling Klebsiella spp. were processed for biochemical profiling and molecular detection using gyrase A (gyrA) gene for conformation. The K pneumoniae isolates were analysed for the presence of drug resistance and virulence genes in their genomes. The 21 of 107 (19.6%) isolates were finally confirmed as K pneumoniae pathogens. An antibiogram study conducted against 17 different antibiotics showed that a majority of the isolates are multidrug resistant. All the isolates (100%) were resistant to amoxicillin, cefixime, amoxicillin‐clavulanic acid, cefotaxime, and ceftriaxone followed by tetracycline (95.2%), ciprofloxacin and gentamicin (76.2%), sulphamethoxazol (66.7%), nalidixic acid (61.9%), norfloxacine (42.9%), piperacillin‐tazobactam (23.8%), cefoperazone‐sulbactam (19%), and cefotaxime‐clavulanic acid (33.3%), whereas all the isolates showed sensitivity to amikacin, chloramphenicol, and imipenem. The presence of tetracycline, sulphamethoxazol‐resistant genes, and extended‐spectrum beta‐lactamase was reconfirmed using different specific genes. The presence of virulence genes fimH1 and EntB responsible for adherence and enterobactin production was confirmed in the isolates. The high virulence and drug resistance potential of these Klebsiella isolates are of high public health concern. Multidrug resistance and virulence potential in K. pneumoniae are converting these nosocomial pathogens into superbugs and making its management harder.     

Genetic diversity of pathogenic leptospires from wild,domestic and captive host species in Portugal

Leptospirosis is a neglected zoonotic disease of worldwide distribution with a significant veterinary and public health impact. It is caused by pathogenic bacteria of the genus Leptospira. The availability of effective tools to accurately identify and type leptospires is of utmost importance for the diagnosis of the disease and for assessing its epidemiology. Several multi‐locus sequence typing (MLST) approaches were described for the typing of worldwide isolates of Leptospira but an extensive agreement towards the adoption of a unique consensus scheme for this agent is still lacking. Most genotyped strains originate from Asian and South American countries, with a minority originating from Europe (being most countries represented only by one or a few isolates). The knowledge of the diversity of circulating leptospires is the key to understanding the disease transmission and its zoonotic implications. In this study, we revisited the taxonomy of several isolates of pathogenic Leptospira obtained from domestic, wild and captive animals in Portugal, between 1990 and 2012. A selection of these isolates was genotyped using two previously published MLST schemes. A total of seven distinct sequence types (STs) were detected among the Portuguese isolates with two STs representing L. borgpetersenii (ST149 and ST152), two STs representing L. kirschneri (ST117 and ST100) and three STs representing L. interrogans (ST17, ST24 and ST140). Global widespread (and maybe more virulent) Leptospira genotypes seem to circulate in Portugal, particularly the L. interrogans ST17 isolates which are associated with several outbreaks of leptospirosis among humans and animals in different regions of the world. This study contributes to the enrichment of the global MLST databases with a new set of allele and sequence type information also providing novel data on circulating Leptospira serovars in Portugal.     

A high prevalence of mupirocin and macrolide resistance determinant among Staphylococcus aureus strains isolated from burnt patients

Infections due to Staphylococcus aureus have become increasingly common among burn patients. The antibiotic resistance profile of S. aureus isolates and inducible resistance against clindamycin were investigated in this study. The presence of mecA gene, mupA gene and macrolide resistance genes were detected using PCR and multiplex-PCR. The resistance rate to methicillin, erythromycin and mupirocin were 58.5%, 58% and 40%, respectively. The prevalence of constitutive and inducible resistance among macrolide resistant isolates was 75% and 25%, respectively. Ninety five percent of the isolates were positive for one or more erm genes. The most common genes were ermA (75%), ermC (72%) and ermB (69%), respectively. The ermA gene predominated in the strains with the inducible phenotype, while ermC was more common in the isolates with the constitutive phenotype. The msrA gene was only found in one MRSA isolate with the constitutive phenotype. A total of 27 isolates (25%) carried the mupA gene. All the mupirocin resistant isolates and almost all the erythromycin resistant isolates were also resistant against methicillin which may indicate an outbreak of MRSA isolates with high-level mupirocin and erythromycin resistance in the burn unit assessed.     

Species distribution of Burkholderia cepacia complex isolates in cystic fibrosis and non-cystic fibrosis patients in New Zealand

Burkholderia cepacia complex (Bcc) isolates from 39 CF patients and 25 non-CF patients in New Zealand were speciated and characterised using the multilocus sequence typing (MLST) scheme for Bcc. B. multivorans predominated in CF patients (31/39, 79.5%) and in non-CF patients (7/25, 28%). Sequence types (ST) with an international distribution were identified (27/64, 42.2%) among the New Zealand Bcc isolates. MLST revealed a high level of diversity among Bcc isolates in CF patients indicating a lack of person-to-person transmission. Non-CF patients showed less diversity in MLST types, however, individuals with shared STs were geographically and chronologically separated. The use of MLST analysis allows continued surveillance of isolates with the potential to identify outbreaks. The identification of internationally distributed strains may provide an indicator of the relative transmissibility and infectivity of these strains and warrants further investigation.     

Antibiotic susceptibility patterns of Neisseria gonorrhoeae isolates in Port Elizabeth.

OBJECTIVE: To survey the antibiotic susceptibility of Neisseria gonorrhoeae isolates. DESIGN: This was a cohort analytical study. SETTING: Three clinics serving different areas in Port Elizabeth. Outcome measures. Prevalence of antibiotic-resistant N. gonorrhoeae isolates. RESULTS: Twenty-one of the 35 isolates (60%) were resistant to ciprofloxacin, while 28 (80%) showed resistance to erythromycin, 17 (48.6%) to penicillin, 3 (8.6%) to doxycycline, 11 (31.4%) to spectinomycin and 33 (94.3%) to tetracycline. CONCLUSION: To ensure effective treatment of gonorrhoea, continued surveillance of antimicrobial susceptibility is necessary.     

新生儿侵袭性感染B族链球菌的耐药表型及耐药机制

目的通过分析侵袭性感染新生儿的B族链球菌（GBS）临床分离株的耐药性和耐药基因型,为新生儿GBS感染的防治和抗菌药物的合理应用提供理论依据。 方法收集2013年1月至2016年6月就诊于广东省4家医院GBS侵袭性感染< 90 d新生儿病例。使用VITEK-2 Compact全自动细菌鉴定及药敏分析系统对GBS分离株进行鉴定和抗菌药物最小抑菌浓度（MIC）测定;应用PCR方法进行红霉素和四环素耐药基因检测。 结果确诊新生儿GBS侵袭性感染93例,其中34例（36.6%）早发型,59例（63.4%）晚发型。93株GBS分离株药物敏感试验结果显示,GBS对青霉素类、头孢菌素类、利奈唑胺和万古霉素均100%敏感;对左氧氟沙星、氧氟沙星和阿奇霉素的耐药率较低,分别为8.6%、2.2%和1.1%。对红霉素、克林霉素和四环素的耐药率高,分别为60.2%、78.5%和93.5%;耐药表型以固有表型（cMLS_B）为主,占53.9%,其次为L表型（26.3%）、诱导表型（iMLS_B）（15.8%）和M表型（3.9%）。56株红霉素耐药菌株ermB基因的携带率为85.7%,2株（3.6%）耐药菌株同时携带ermB和mefA基因,均未检出ermA。87株四环素耐药菌株中,四环素耐药基因tetO和tetM携带率分别为74.7%和46%,其中25株同时携带tetO和tetM,均未检出tetL和tetK基因。 结论青霉素和氨苄西林仍是治疗新生儿侵袭性GBS感染及高危新生儿预防GBS感染的首选药物。广东地区GBS红霉素耐药机制以ermB基因介导的核糖体靶位改变为主,四环素耐药机制以tetO和tetM基因为主。     

Phenotypic and genotypic analyses of antimicrobial resistant bacteria in livestock in Uganda

Antimicrobial resistant bacteria (ARB) in livestock are a global public health concern, not only because they prolong infectious diseases but also they can be transferred from animals to humans via the food chain. Here, we studied ARB in livestock at commercial and subsistence farms (n = 13) in Wakiso and Mpigi districts, Uganda. We enquired from the farmers about the type and the purpose of antimicrobial agents they have used to treat their livestock. After collecting faeces, we isolated antimicrobial resistant Escherichia coli from livestock faeces (n = 134) as an indicator bacterium. These strains showed resistance to ampicillin (44.8%), tetracycline (97.0%), and sulfamethoxazole‐trimethoprim (56.7%). The frequency of ampicillin‐resistance was significantly correlated with the usage of penicillins to livestock in the farms (p = 0.04). The metagenomics data detected 911 antimicrobial resistant genes that were classified into 16 categories. Genes for multidrug efflux pumps were the most prevalent category in all except in one sample. Interestingly, the genes encoding third‐generation cephalosporins (bla_CTX‐M), carbapenems (bla_ACT), and colistin (arnA) were detected by metagenomics analysis although these phenotypes were not detected in our E. coli strains. Our results suggest that the emergence and transmission of cephalosporin, carbapenem, and/or colistin‐resistant bacteria among livestock can occur in future if these antimicrobial agents are used.     

Genetic characterization and epidemiological implications of Campylobacter isolates from wild birds in South Korea

In this study, we genotyped Campylobacter isolates from wild birds by multilocus sequence typing (MLST) and analysed their virulence genes by PCR with the aim to gain a deeper understanding of the epidemiology of Campylobacter infection. Amongst 60 Campylobacter isolates from 12 wild bird species, we identified 32 sequence types (STs; 29 STs from Campylobacter jejuni and 3 STs from Campylobacter coli). Clonal complex 45 (CC‐45), was the most common CC (n = 17 isolates), followed by CC‐692 (n = 10). ST‐137 was the most prevalent (n = 9), originating from 4 avian species. Eleven C. jejuni STs (37.9%) and 2 C. coli STs (66.7%) overlapped with those of human clinical origin. Thirteen C. jejuni STs and all 3 C. coli STs from wild birds were associated with STs of multiple sources (poultry, livestock and/or the environment). There was a strong association between wild bird isolates and domestic duck isolates with 7 STs shared between these host species. There was a high prevalence of all the 11 virulence genes tested in all wild bird isolates, with no association of any ST to a particular virulence profile. All Campylobacter spp. isolates from wild birds carried the cadF gene. The cytotoxin‐encoding genes cdtB and cdtC were present in all 7 C. coli isolates, and in 52 (98.1%) and 50 (94.3%) C. jejuni isolates, respectively. Six C. jejuni isolates carried the wlaN gene, and virB11 was found in 8 isolates. The results of this study show that ST overlap between human and wild bird isolates frequently occurs, and the high prevalence of virulence genes in wild bird isolates indicates that wild birds shed Campylobacter in their faeces that are potentially pathogenic to humans.