Rational design of a 500 m3 fermenter for erythromycin production by Saccharopolyspora erythraea / 生物工程学报

Erythromycin is a macrolide antibiotic produced by Saccharopolyspora erythraea. Its yield is greatly affected by the fermentation conditions and the bioreactor configurations. In this study, a novel scale-up method for erythromycin fermentation was developed based on computational fluid dynamics (CFD) and time constant analysis. Firstly, the dissolved oxygen (DO) was determined as a key parameter according to the physiological properties of S. erythraea cultivated in a 50 L bioreactor. It was found that the time constant of oxygen supply (tmt) in a 500 m3 bioreactor should be less than 6.25 s in order to satisfy the organism's oxygen uptake rate (OUR). Subsequently, a 500 m3 bioreactor was designed using the time constant method combined with empirical correlations. The impeller combination with one BDT8 impeller at bottom and two MSX4 impellers at upper part was determined, and then validated by numerical simulation. The results indicated that the tmt of the bioreactor (< 6.25 s) and the fluid properties, including gas hold-up, shear stress and fluid vector, met the requirements of erythromycin fermentation. Finally, the industrial production of erythromycin in the 500 m3 showed the design method was applicable in large scale fermentation.

Isolation and characterization of vancomycin and erythromycin resistant Staphylococcus aureus from Cairo, Egypt

Aims@#Staphylococcus aureus is an important opportunistic human pathogen. The emergence of macrolide and vancomycin resistant S. aureus is of great concern for treatment of S. aureus infections. The current study aimed to investigate the pattern of antibiotic resistance in S. aureus clinical isolates recovered from El Boos Students’ hospital in Cairo, Egypt.@*Methodology and results@#Sixty unduplicated S. aureus isolates were recovered from El Boos Students’ hospital in Cairo, Egypt for 11 months period. The antibiotic susceptibility test revealed that all isolates were resistant to eleven antibiotics, but only 49 S. aureus isolates were resistant to cefoxitin. The minimum inhibitory concentrations (MIC) of both erythromycin and vancomycin were determined by broth microdilution method. Two methicillin resistant S. aureus (MRSA) isolates showing tolerance to both erythromycin and vancomycin at high concentration were selected for further characterization. One isolate was recovered from eye infection and had MIC at 256 µg/mL of both erythromycin and vancomycin. While another isolate was recovered from throat infection and had MIC of erythromycin and vancomycin up till 512 µg/mL. The presence of resistance genes (ermA, ermB, ermC, mef, msrA, vanA and vanB) were confirmed by polymerase chain reaction (PCR). Both MRSA isolates carried all tested resistance genes.@*Conclusion, significance and impact of study@#This study highlights the concern of presence of multidrug-resistant S. aureus which showed resistance to high concentrations of erythromycin, vancomycin and carried ermA, ermB, ermC, mef, msrA, vanA and vanB genes, therefore imposes risk of failure to treat such infections.

Phenotypic and molecular characterization of erythromycin resistance in Campylobacter jejuni and Campylobacter coli strains isolated from swine and broiler chickens / Caracterização fenotípica e molecular da resistência à eritromicina em cepas de Campylobacter jejuni e Campylobacter coli isoladas de suínos e frangos de corte

Campylobacter spp. is a bacterial agent that causes gastroenteritis in humans and may trigger Guillain-Barré Syndrome (GBS) and is also considered one of the main foodborne diseases in developed countries. Poultry and pigs are considered reservoirs of these microorganisms, as well as raw or undercooked by-products are often incriminated as a source of human infection. Treatment in human cases is with macrolide, such erythromycin, that inhibits the protein synthesis of the microorganism. This study aimed to isolate Campylobacter jejuni and Campylobacter coli from intestinal content samples of broiler chickens (n=20) and swine (n=30) to characterize the erythromycin resistance profile of the strains and to detect molecular mechanisms involved in this resistance. The minimum inhibitory concentration was determined by agar dilution. The Mismatch Amplification Mutation Assay-Polymerase Chain Reaction (MAMA-PCR) was performed to detect mutations at positions 2074 and 2075 of 23S rRNA region, in addition to PCR test to detect the erm(B) gene. From the intestinal content of broiler chickens, 18 strains of C. jejuni and two strains of C. coli were isolated, whereas, from swine samples, no C. jejuni strain and 14 strains of C. coli were isolated. All C. coli strains were resistant, and three C. jejuni strains from broilers chickens were characterized with intermediate resistance to erythromycin. The MIC of the strains ranged from ≤0.5mg/μL to ≥128mg/μL. All resistant strains had the A2075G mutation, and one strain with intermediate resistance had the A2075G mutation. However, the A2074C mutation and the erm(B) gene were not detected. High resistance levels were detected in C. coli strains isolated from swine. The MAMA-PCR is a practical tool for detecting the erythromycin resistance in Campylobacter strains.(AU)

Campylobacter spp. é um agente bacteriano causador de gastroenterite em humanos e associado à síndrome de Guillain-Barré, sendo a campilobacteriose considerada uma das principais enfermidades de origem alimentar. Aves e suínos são importantes reservatórios desses microrganismos e seus produtos derivados crus ou mal cozidos são muitas vezes incriminados como fonte de infecção humana. A primeira escolha para o tratamento em casos humanos são os antimicrobianos da classe dos macrolídeos como à eritromicina. Dentro desse contexto, o objetivo deste estudo foi isolar Campylobacter jejuni e C. coli a partir de 20 amostras de conteúdo intestinal de frangos de corte e de 30 de suínos ao abate e investigar a resistência à eritromicina das estirpes obtidas e os possíveis mecanismos moleculares envolvidos nesta resistência. A concentração inibitória mínima foi determinada pela diluição em ágar e a técnica MAMA-PCR foi utilizada para detecção de mutações nas posições 2074 e 2075 da região 23s rRNA, foi pesquisado também a presença do gene erm(B) pela PCR. A partir do conteúdo intestinal de frangos de corte foram isoladas 18 estirpes de C. jejuni e duas de C. coli, enquanto de suínos foram obtidas 14 estirpes de C. coli e nenhuma estirpe de C. jejuni. Todas as estirpes de C. coli de suínos foram identificadas como resistentes e três estirpes de C. jejuni de frangos foram caracterizadas com resistência intermediária. A CIM das estirpes variou de ≤0,5mg/μL a ≥128mg/μL. Todas as estirpes resistentes tinham a mutação A2075G e uma cepa com resistência intermediária também apresentou a mutação A2075G. Não foi detectada a mutação A2074C ou a presença do gene erm(B) em nenhuma das estirpes obtidas. Os resultados revelam um alto nível de resistência em estirpes de C. coli isoladas de suínos frente a eritromicina. A técnica MAMA PCR utilizada se constitui em uma ferramenta prática para detecção da resistência à eritromicina em estirpes de C. jejuni e C. coli.(AU)

Antibiotic resistance of Enterococcus faecalis from persistent endodontic infections / Resistencia antibiótica de Enterococcus faecalis provenientes de infecciones endodónticas persistentes

Enterococci are important nosocomial pathogens due to their intrinsic multiresistance and the acquisition of new antibiotic resistance genes (ARG). Enterococcus faecalis has been shown to be one of the main pathogens in persistent endodontic infections, therefore, the main objective of this study was to evaluate the phenotype and resistance genotype of strains of E. faecalis isolated from teeth with persistent endodontic lesions, to the most commonly prescribed antibiotics in dentistry. Thirteen strains of E. faecalis of different pulsotype were analyzed to evaluate the susceptibility to antibiotics, amoxicillin, amoxicillin/clavulanic acid, tetracycline, erythromycin and metronidazole, using the Epsilometer test (E- test) and the presence of beta-lactamases with nitrocefin test. Finally, the detection of ARG was performed with a molecular polymerase chain reaction (PCR) technique and confirmed by the sequencing of the amplification products. Fisher's exact test was used, using 95 % confidence. Regarding the phenotype of resistance, the evaluated strains, independent of the pulsotype, were totally resistant to the action of metronidazole. Antibiotics with higher minimum inhibitory concentration (MIC) after metronidazole include tetracycline and erythromycin. In contrast, lower MIC are applied to the combination of amoxicillin with clavulanic acid. The nitrocefin test was positive only in one strain. Genotypically, two genetically distant strains isolated from a single patient, presented a genotype of resistance to erythromycin, determined by the presence of the ermB gene. No statistically significant relationship was found between phenotypic resistance and the presence of ARG in relation to erythromycin (p> 0.05). It was concluded that isolates of E. faecalis from persistent endodontic infections showed phenotypes of resistance to several antimicrobial agents, all of which were susceptible to amoxicillin/clavulanic acid. Periodic evaluation of susceptibility to antibiotics is suggested as an important practice for the surveillance of antibiotic resistance in oral strains.

Los enterococos son importantes patógenos nosocomiales debido a su multi resistencia intrínseca y la adquisición de nuevos genes de resistencia a los antibióticos (ARG). Enterococcus faecalis es uno de los principales patógenos en infecciones endodónticas persistentes, por lo tanto, el objetivo principal de este estudio fue evaluar el fenotipo y el genotipo de resistencia de cepas de E. faecalis aisladas de dientes con lesiones endodóncicas persistentes, a los antibióticos comúnmente recetados en odontología. Se analizaron 13 cepas de E. faecalis de diferentes pulsotipos para evaluar la susceptibilidad a los antibióticos, amoxicilina, amoxicilina / ácido clavulánico, tetraciclina, eritromicina y metronidazol, utilizando la prueba de Epsilometría (E-test) y la presencia de beta-lactamasas con prueba de nitrocefina. Finalmente, la detección de ARG se realizó con una técnica molecular de reacción en cadena de la polimerasa (PCR) y se confirmó mediante la secuenciación de los productos de amplificación. Se utilizó la prueba exacta de Fisher, con un 95 % de confianza. En cuanto al fenotipo de resistencia, las cepas evaluadas, independientes del pulsotipo, fueron totalmente resistentes a la acción del metronidazol. Los antibióticos con los valores más altos de concentración mínima inibitoria (CMI) después del metronidazol incluyen tetraciclina y eritromicina. En contraste, las CMI mas bajas se aplican a la combinación de amoxicilina con ácido clavulánico. La prueba de nitrocefina fue positiva solo en una cepa. Genotípicamente, dos cepas distantes genéticamente, aisladas de un mismo paciente fueron positivas para el gen ermB. No se encontró una relación estadísticamente significativa entre la resistencia fenotípica y la presencia de ARG en relación con la eritromicina (p> 0,05). Se concluyó que los aislamientos de E. faecalis de infecciones endodónticas persistentes mostraron fenotipos de resistencia a varios agentes antimicrobianos, todos los cuales fueron susceptibles a amoxicilina / ácido clavulánico. Se sugiere una evaluación periódica de la susceptibilidad a los antibióticos como una práctica importante para la vigilancia de la resistencia a los antibióticos en las cepas orales.

Prevalence and antibiotic susceptibility of group A beta-haemolytic streptococcal isolates in children presenting with acute pharyngitis in Lusaka, Zambia

Background. Group A beta-haemolytic streptococci (GABHS)-associated pharyngitis can complicate into rheumatic fever and rheumatic heart disease (RHD).Objectives. To determine the prevalence and antibiotic susceptibility of GABHS isolates in children presenting with acute pharyngitis and assess the utility of Zambian Treatment Guideline (ZTG) criteria as a local clinical scoring system.Methods. This descriptive cross-sectional study was conducted at the paediatric outpatient department of the University Teaching Hospital in Lusaka, Zambia. The study cohort, comprising children aged 3 - 15 years (n=146), were recruited as presenting with symptoms of pharyngitis. The children underwent a clinical assessment that included a detailed case history, presenting symptoms and a throat swab that was subsequently cultured. Microbial isolates were typed and the antibiotic sensitivity of cultured GABHS to penicillin and erythromycin determined.Results. GABHS were cultured from 22 (15.1%) children within this study. All the GABHS isolates (n=22) were susceptible to penicillin G; however, 19% of isolates displayed reduced susceptibility to erythromycin. None of the ZTG criteria, when used individually, was sufficiently sensitive to detect GABHS pharyngitis among this cohort.Conclusion. The prevalence of GABHS pharyngitis is similar that been described elsewhere. While GABHS remains highly susceptible to penicillin, which is used in the local RHD control programmes, concern remains for children treated with erythromycin owing to the resistance noted in some of the isolates. The ZTG clinical criteria displayed poor sensitivity in identifying GABHS pharyngitis. This has significant implications for effective diagnosis and treatment of pharyngitis and associated complications within this high RHD endemic area

Susceptibilidad antimicrobiana en muestras urogenitales de ureaplasma urealyticum, el principal agente en infección intramaniótica / Antimicrobial susceptibility in urogenital samples of ureaplasma urealyticum, the main agent in intramaniotic infection

RESUMEN OBJETIVO: Ureaplasma urealyticum es el agente más frecuentemente aislado en infección intraamniótica. Los macrólidos son los antimicrobianos de primera elección en embarazadas. Se ha descrito el aumento de resistencia, pudiendo limitar las opciones terapéuticas durante la gestación. El propósito del estudio es evaluar susceptibilidad antimicrobiana de Ureaplasma urealyticum aislado en mujeres en edad fértil, que se atienden en Clínica Alemana Temuco, Araucanía, Chile. METODO: Se estudian todas las muestras de orina y flujo vaginal para cultivo de U. urealyticum, de pacientes entre 18 y 40 años, recibidas en el Laboratorio de Microbiología Clínica Alemana Temuco, en período Abril 2013 a Enero 2015. Se procesan las muestras con kit Mycoplasma IST 2 de Biomerieux. En las que resultan positivas, se estudia susceptibilidad a macrólidos, tetraciclinas y quinolonas. RESULTADOS: 426 muestras de orina y flujo vaginal (390 pacientes). 197 pacientes resultaron positivas para U. urealyticum. (50,5%). La susceptibilidad fue 88,4% (174 pctes) a Eritromicina, 87,9% (173 pctes) a Claritromicina y 91,9% (181 pctes) a Azitromicina (NS). 15 de 197 pacientes (7,6%) fueron resistentes a los 3 macrólidos. La susceptibilidad a Quinolonas fue 55,3% a Ciprofloxacino, y 94% a Ofloxacino. El 100% resultó susceptible a Tetraciclinas. CONCLUSIONES: Cerca del 10% de U. urealyticum aislados en nuestra serie son resistentes a macrólidos, contribuyendo a la no erradicación de la infección en tratamientos empíricos. Dentro de ellos, azitromicina aparece con la mayor efectividad. El aumento de resistencia limitará opciones terapéuticas, con gran impacto perinatal en futuro. La vigilancia de susceptibilidad en cada hospital es fundamental para elección terapéutica.

ABSTRACT INTRODUCTION: Ureaplasma urealyticum is the most frequently isolated microorganism in intra-amniotic infection. The macrolides are the first choice antimicrobials for treat this infection in pregnancy. The increasing resistance has been described worldwide, seriously limiting therapeutic options in pregnancy. The aim of the study is to evaluate antimicrobial susceptibility of U. urealyticum aislated in fertile-age women in Clínica Alemana Temuco, Araucania region, Chile. METHOD: Urine and vaginal samples were analyzed for U. urealyticum, from every 18 to 40 years old patients, received at Microbiology Laboratory of Clínica Alemana Temuco, between April 2013 to January 2015. The samples are processed with Mycoplasma IST 2 kit of Biomerieux. If they became positives, susceptibility to macrolides, tetracyclines and quinolones was studied. RESULTS: 426 urine and vaginal samples were collected (390 patients). 197 patients were positive for U. urealyticum (50.5%). The susceptibility was 88.4% (174 pts) to Erythromicyn, 87.9% (173 pts) to Clarithromycin and 91.9% (181 pts) to Azithromycin (NS). Resistance to all macrolides was observed in 15 out of 197 patients (7.6%). The susceptibility to Quinolones was 55.3% to Ciprofloxacin, and 94% to Ofloxacin. The 100% was susceptible to Tetracyclines. DISCUSSION: Near to 10% of isolated Ureaplasma spp in our serie were resistant to some macrolide, being a factor for failing to eradicate the infection in empirical treatment. Azithromycin was the most effective. The increasing resistance will limit therapeutic options, with great perinatal impact in the future. Susceptibility surveillance in each hospital is very important for therapeutic options.

Antimicrobial susceptibility and antigen genotypes of Bordetella pertussis strains isolated from neonates / 中国当代儿科杂志

OBJECTIVE@#To investigate the alternative antimicrobial drugs for the treatment of neonatal pertussis and the antigen genotypes of Bordetella pertussis (B. pertussis) strains.@*METHODS@#A total of 32 B. pertussis strains isolated from neonates between May 2013 and July 2018 were used in this study. E-test stripes were used to measure the minimal inhibitory concentration (MIC) of 18 antimicrobial drugs including erythromycin, sulfamethoxazole-trimethoprim (SMZ) and ampicillin. The 23S rRNA gene of isolated strains was amplified and sequenced to identify the mutation site of erythromycin resistance gene, and the seven antigen genotypes of B. pertussis strains (ptxA, ptxC, ptxP, prn, fim2, fim3 and tcfA2) were analyzed.@*RESULTS@#Of the 32 B. pertussis strains, 25 (78%) were resistant to erythromycin, azithromycin, clarithromycin and clindamycin, with an MIC of >256 mg/L, and A2047G mutation was observed in the 23S rRNA gene. All strains had an MIC of ≤0.064 mg/L for SMZ. The MIC of ampicillin, amoxicillin, amoxicillin-clavulanic acid and ceftriaxone ranged from 0.032 to 1 mg/L. The strains resistant to macrolide antibiotics had an antigen genotype of ptxA1/ptxC1/ptxP1/prn1/fim2-1/fim3-1/tcfA2.@*CONCLUSIONS@#B. pertussis strains from neonates are often resistant to macrolides, and the in vitro test shows that off-label use of sulfonamides is a reliable regimen for the treatment of neonates with macrolide-resistant pertussis. The prevalence of drug-resistant strains further emphasizes the importance of immunoprophylaxis.

Evaluation of commercial probiotic lactic cultures against biofilm formation by Cronobacter sakazakii

BACKGROUND/AIMS: Cronobacter sakazakii, an emergent pathogen is considered as a major concern to infants and neonates fed on reconstituted powdered infant milk formula. In conjunction with many other factors, biofilm forming capacity adds to its pathogenic potential. In view of the facts that infants are at highest risk to C. sakazakii infections, and emerging antibiotic resistance among pathogens, it is imperative to evaluate probiotic cultures for their efficacy against C. sakazakii. Therefore, pure probiotic strains were isolated from commercial probiotic products and tested for their antimicrobial and anti-biofilm activities against C. sakazakii. METHODS: A total of 6 probiotic strains were tested for their antibiotic susceptibility followed by antimicrobial activity using cell-free supernatant (CFS) against C. sakazakii. The inhibitory activity of CFS against biofilm formation by C. sakazakii was determined using standard crystal violet assay and microscopic observations. RESULTS: All the probiotic strains were sensitive to ampicillin, tetracycline, vancomycin and carbenicillin whereas most of the strains were resistant to erythromycin and novobiocin. Four of the 6 probiotic derived CFS possessed antimicrobial activity against C. sakazakii at a level of 40 μL. A higher biofilm inhibitory activity (>80%) was observed at initial stages of biofilm formation with weaker activity during longer incubation upto 48 hours (50%–60%). CONCLUSIONS: The study indicated the efficacy of isolated commercial probiotics strains as potential inhibitor of biofilm formation by C. sakazakii and could be further explored for novel bioactive molecules to limit the emerging infections of C. sakazakii.

Antimicrobial Susceptibility and Genetic Analysis of Campylobacter jejuni Isolated from Diarrhea Patients in Busan / 대한임상미생물학회지

BACKGROUND: Campylobacter jejuni is an important food-borne pathogen that causes human gastroenteritis. This study was conducted to investigate the incidence of isolation, antimicrobial susceptibility pattern, and C. jejuni genotype from diarrhea patients in Busan, Korea. METHODS: A total of 97 C. jejuni were isolated from diarrhea patients during five food-borne outbreaks from 2014 to September 2017. Antimicrobial susceptibility tests were carried out by the broth microdilution method for ciprofloxacin (CIP), nalidixic acid (NAL), tetracycline (TET), chloramphenicol, azithromycin (AZI), erythromycin (ERY), streptomycin (STR), gentamicin, and telithromycin. To investigate C. jejuni genotypes, pulsed-field gel electrophoresis (PFGE) profile analysis was performed. RESULTS: The isolation rate of C. jejuni was 2.0% for the last 4 years and increased annually. Antimicrobial resistance rates of C. jejuni were shown to be in the order of NAL (90.9%), CIP (89.4%), TET (13.6%), AZI (3.0%), ERY (3.0%), and STR (1.5%). The proportion of multidrug-resistance was 18.2%, and they commonly contained quinolones (CIP-NAL). Analysis of PFGE patterns of SmaI-restricted DNA of C. jejuni isolates showed 17 clusters; cluster 11 was the major genotype pattern. CONCLUSION: This study will provide useful data for the proper use of antimicrobials and the management of resistant C. jejuni. Also it will help to provide data for the epidemiological investigation of foodborne diseases caused by C. jejuni, which is expected to increase in the future.

Antibiotics Susceptability of Streptococcus pneumoniae Isolated from Single Tertiary Childrens' Hospital Since 2014 and Choice of Appropriate Empirical Antibiotics

PURPOSE: We investigated the distribution and antimicrobial resistance of pneumococcal isolates from hospitalized children at Asan Medical Center for recent 4 years, and aimed to recommend proper choice of empirical antibiotics for pneumococcal infection. METHODS: From March 2014 to May 2018, children admitted to Asan Medical Center Childrens' Hospital with pneumococcal infection were subjected for evaluation of minimal inhibitory concentration (MIC) for β-lactams and macrolide antibiotics. Patient's age, underlying disease, gender were retrospectively collected. Using Monte Carlo simulation model and MIC from our study, we predicted the rate of treatment success with amoxicillin treatment. RESULTS: Sixty-three isolates were analyzed including 20.6% (n=13) of invasive isolates, and 79.4% (n=50) of non-invasive isolates; median age were 3.3 years old, and 87.3% of the pneumococcal infections occurred to children with underlying disease. Overall susceptibility rate was 49.2%, 68.2%, and 74.6% for amoxicillin, parenteral penicillin, and cefotaxime respectively. 23.8% and 9.5% of the isolates showed high resistance for amoxicillin, and cefotaxime. Only 4.8% (n=3) were susceptible to erythromycin. Monte Carlo simulation model revealed the likelihood of treatment success was 46.0% at the dosage of 90 mg/kg/day of amoxicillin. CONCLUSIONS: Recent pneumococcal isolates from pediatric patients with underlying disease revealed high resistance for amoxicillin and cefotaxime, and high resistance for erythromycin. Prudent choice of antibiotics based on the local data of resistance cannot be emphasized enough, especially in high risk patients with underlying disease, and timely vaccination should be implemented for prevention of the spread of resistant strains.

Positive culture rate and antimicrobial susceptibilities of Mycoplasma hominis and Ureaplasma urealyticum

OBJECTIVE: To assess positive culture rate and antimicrobial susceptibilities of Mycoplasma hominis (MH) and Ureaplasma urealyticum (UU) in symptomatic general population and pregnant women admitted with preterm labor and premature rupture of membranes. METHODS: We retrospectively reviewed medical records of patients who have undergone culture test and antimicrobial susceptibilities at our center from January 2017 to April 2018. Patients with positive culture for MH, UU, or both were included in this study. RESULTS: There were 200 patients who were eligible for enrollment. Of these patients, 34 (17%) were pregnant women and 166 (83%) were non-pregnant women. Of these 200 patients, positive culture results were as follows: MH only, n=10 (5%); UU only, n=58 (29%); and both MH and UU, n=36 (18%). Susceptibilities of MH only to doxycycline, erythromycin, ciprofloxacin, and azithromycin were 100%, 10%, 40%, and 0%, respectively. Susceptibilities of UU only to doxycycline, erythromycin, ciprofloxacin, and azithromycin were 94.8%, 87.9%, 5.2%, and 81%, respectively. Susceptibilities of both MH and UU to doxycycline, erythromycin, ciprofloxacin, and azithromycin were 97.2%, 5.6%, 11.1%, and 11.1%, respectively. CONCLUSION: UU only was the leading causative pathogen for genitourinary infection in our study. MH only accounted for about one sixth of UU only infections. Doxycycline was still the best antibiotics as most patients with MH only, UU only, or both MH and UU positive culture showed susceptibility. For ciprofloxacin, less than 12% of those with UU only and both MH and UU culture positive results showed susceptibility.

Antimicrobial resistance profiles of vancomycin-resistant Enterococcus species isolated from laboratory mice

Isolates of 24 enterococci, 5 Enterococcus casseliflavus and 19 Enterococcus gallinarum, possessing vanC genes and showing low-level resistance to vancomycin were obtained from mice from commercial mouse breeding companies. Since some of these isolates showed resistance to other antibiotics, the purpose of this study was to clarify the resistant profiles of these isolates. One E. casseliflavus isolate showed resistance to erythromycin with a minimal inhibitory concentration (MIC) of 8 μg/mL and also showed apparent resistance to fluoroquinolones with an MIC of 32 μg/mL for ciprofloxacin. The MICs of 2 other fluoroquinolone-resistant E. casseliflavus and E. gallinarum isolates were 3 and 6 μg/mL, respectively. These 3 resistant isolates showed an absence of macrolide- and fluoroquinolone-resistant genes, including amino acid substitutions in the quinolone resistance determining regions of DNA gyrase and topoisomerase IV. Resistance to tetracycline was detected in 2 E. gallinarum isolates that were highly resistant, exhibiting MICs of 48 and 64 μg/mL and possessing tet(O) genes. The results indicate that antibiotic-resistant enterococci are being maintained in some laboratory mouse strains that have never been treated with an antibiotic.

Evaluation of in vitro antimicrobial susceptibility of Bacillus anthracis strains isolated during anthrax outbreaks in Italy from 1984 to 2017

Anthrax, caused by Bacillus anthracis, is a non-contagious infectious disease that affects a wide range of animal species (primarily ruminants) including humans. Due to the often-fatal outcome in humans, quick administration of definitely effective antimicrobials is crucial either as prophylaxis or as a clinical case therapy. In this study, 110 B. anthracis strains, temporally, geographically, and genetically different, isolated during anthrax outbreaks in Italy from 1984 to 2017, were screened using a broth microdilution method to determine their susceptibility to 16 clinically relevant antimicrobial agents. The strains were isolated from various matrices (human, animal, and environmental samples) and were representative of thirty distinct genotypes previously identified by 15-loci multiple-locus variable-number of tandem repeats analysis. The antimicrobials tested were gentamicin, ceftriaxone, streptomycin, penicillin G, clindamycin, chloramphenicol, vancomycin, linezolid, cefotaxime, tetracycline, erythromycin, rifampin, amoxicillin, ciprofloxacin, doxycycline, and trimethoprim. All isolates were susceptible to most of the tested antimicrobials, with the exception of trimethoprim for which all of them showed high minimal inhibitory concentration values. An intermediate level of susceptibility was recorded for ceftriaxone and cefotaxime. Although the Centers for Disease Control and Prevention recommend the use of doxycycline, ciprofloxacin, penicillin G, and amoxicillin for treatment of human cases and for post-exposure prophylaxis to anthrax spores, this study shows a high degree of in vitro susceptibility of B. anthracis to many other antimicrobials, suggesting the possibility of an alternative choice for prophylaxis and therapy.

Resistência de Neisseria gonorrhoeae a antimicrobianos na prática clínica: como está o Brasil? / Antimicrobials resistance of Neisseria gonorrhoeae in clinical practice: where Brazil stands?

Estima-se que um milhão de infecções sexualmente transmissíveis (IST) sejam adquiridas por dia no mundo, segundo a Organização Mundial da Saúde. Elas podem ser causadas por diversos micro-organismos pelo contato sexual. Embora tratáveis, as infecções, como a clamidiana, sífilis, tricomoníase e gonorreia, são responsáveis por 350 milhões de novos casos de IST anualmente no mundo. A gonorreia é a segunda IST bacteriana mais prevalente no planeta e tem chamado atenção nos últimos anos em decorrência da baixa eficácia em seu tratamento. O agente etiológico é a Neisseria gonorrhoeae. Na maioria das mulheres, a infecção por esse micro-organismo é assintomática, dificultando ainda mais seu diagnóstico e tratamento e, portanto, aumentando o risco de desenvolvimento de suas complicações associadas. Mesmo quando diagnosticada, essa infecção está sujeita a um alto índice de insucesso terapêutico que se deve, principalmente, à grande plasticidade genética da N. gonorrhoeae para aquisição de genes cromossômicos ou plasmidiais de resistência. O aumento da resistência desse micro-organismo a antimicrobianos comumente utilizados no tratamento, como penicilina, tetraciclina e ciprofloxacina, tem sido relatado em diversos países. No Brasil, poucos estudos estão disponíveis, mas em alguns estados já foram relatadas linhagens resistentes à ciprofloxacina. Dessa forma, deve-se ressaltar a importância de novos estudos que visem descrever o perfil da resistência da N. gonorrhoeae a antimicrobianos. Tais achados certamente nortearão a implementação de sistemas de vigilância epidemiológica no país visto que, até o momento, as infecções por N. gonorrhoeae sequer estão incluídas na lista nacional de doenças e agravos de notificação compulsória.(AU)

According to the World Health Organization, approximately one million sexually transmitted infections (STI) are acquired daily in the world. These infections can be caused by several microorganisms via contact. The treatable STI, such as chlamydia, syphilis, trichomoniasis and gonorrhea, account for 350 million new cases of STI each year worldwide. Gonorrhoea is caused by Neisseria gonorrhoeae and is the second most common bacterial STI in the world. It has drawn more attention in the last years due to the low efficacy in its treatment. Most women with this infection are asymptomatic, which makes its diagnosis and treatment troublesome increasing the risk for its associated complications. Even when diagnosed, this infection is subject to a high rate of therapeutic failure mainly due to the great genetic plasticity of N. gonorrhoeae for the acquisition of chromosomal or resistance plasmid enes. Increased resistance of this microorganism to antimicrobials commonly used in treatment such as penicillin, tetracycline and ciprofloxacin has been reported in several countries. In Brazil, few studies are available, but in some states strains resistant to ciprofloxacin were alreadyreported. The refore, it is important to highlight the importance of new studies aimed at describing the resistance profile of N. gonorrhoeae to antimicrobials in Brazil context. These findings will certainly guide the implementation of epidemiological surveillance systems in the country, since until now N. gonorrhoeae infections do not figure into the national list of compulsorily notifiable diseases.(AU)

Epidemiología de la faringitis aguda bacteriana en un hospital general de agudos / Epidemiology of acute bacterial pharyngitis in a general acute care hospital / Epidemiologia da faringite bacteriana aguda em um hospital geral de cuidados agudos

La faringitis aguda bacteriana (FAB) representa entre un 20 a 30% de las faringitis. El principal agente causal es Streptococcus pyogenes. Se revisó retrospectivamente la información microbiológica disponible entre 2010 y 2016, para analizar la incidencia de la FAB, sus agentes causales, la incidencia de casos según el período estacional y rango etario. Se determinó el porcentaje de resistencia (R) de S. pyogenes a eritromicina y el fenotipo predominante. Se diagnosticó FAB en 21,5% de 3.246 cultivos, donde 89% fueron causados por S. pyogenes. El 35,3% de las FAB se presentó en niños de 7 a 10 años, seguido por el grupo de mayores de 15 años (31,3%). Se evidenció un aumento de faringitis por Streptococcus dysgalactiae subsp. equisimilis en 2011 y 2014; 56,2% de los casos se diagnosticaron en mayores de 15 años. Hubo 3 casos de FAB por Arcanobacterium haemolyticum. El 36,1% de las faringitis se presentaron en primavera, con un aumento significativo durante las correspondientes a 2010 y 2016. La R global a eritromicina en S. pyogenes fue del 16,6% con predominio del fenotipo M. El valor de R encontrado fue superior al ser comparado con otras estadísticas similares, lo que demostró la importancia de monitorear este dato, dado que es el antibiótico alternativo en pacientes alérgicos a penicilina.

Acute bacterial pharyngitis (ABP) accounts for 20 to 30% of acute pharyngitis. The most common bacterial agent is Streptococcus pyogenes. A retrospective, record-based study was carried out based on the microbiological records from 2010 to 2016, analyzing ABP's incidence, its causal agents and its incidence according to the season and age range. Erythromycin resistance and the main resistance phenotype were determined in S. pyogenes. Acute bacterial pharyngitis was diagnosed in 21.5% out of 3.246 cultures, 89% were due to S. pyogenes, 36.3% of patients were children between 7 to 10 years old and 31.3% were older than 15 years of age. There was a significant increase in pharyngitis due to Streptococcus dysgalactiae subsp. equisimilis since 2010 (p<0.05), 52.5% were detected in patients older than 15 years of age. There were only three cases of ABP produced by Arcanobacterium haemolyticum. A total of 36.1% of pharyngitis occurred during spring, with a significant increase during 2010 and 2016 springs. Global erythromycin resistance in S. pyogenes was 16.6% with predominance of the M phenotype. This resistance rate is higher than that described in other similar series, demonstrating the importance of continuously monitoring of macrolide R in S. pyogenes, since they are the antibiotics of choice to treat pharyngitis in patients allergic to penicillin.

A faringite bacteriana aguda (FAB) representa entre 20 e 30% das faringites. O principal agente causador é Streptococcus pyogenes. Foi revista retrospectivamente a informação microbiológica disponível entre 2010 e 2016, para analisar a incidência da FAB, seus agentes causadores, a incidência de casos de acordo com o período sazonal e a faixa etária. A percentagem de resistência (R) de S. pyogenes à eritromicina e ao fenótipo predominante foram determinadas. Foi diagnosticado FAB em 21,5% de 3,246 culturas, 89% das quais foram causadas por S. pyogenes. 35,3% das FAB se apresentou em crianças de 7 a 10 anos, seguidas pelo grupo de mais de 15 anos (31,3%). Houve aumento de faringite por Streptococcus dysgalactiae subsp. equisimilis em 2011 e 2014; 56,2% dos casos foram diagnosticados em jovens de mais de 15 anos. Houve 3 casos de FAB por Arcanobacterium haemolyticum. 36,1% das faringites ocorreu na primavera, com um aumento significativo em 2010 e 2016. A R global a eritromicina em S. pyogenes foi de 16,6% com prevalência do fenótipo M. O valor de R encontrado foi superior em comparação com outras estatísticas semelhantes, demonstrando a importância de monitorar esse dado, pois é o antibiótico alternativo em pacientes alérgicos à penicilina.

Nocardia abscessus Cutaneous Abscess: A Case Report and Review of the Literature / 대한임상미생물학회지

We describe a cutaneous abscess caused by Nocardia abscessus in a previously healthy woman. A 74-year-old woman presented with recurrent bullae on her left forearm that developed 1 week prior and was initially suspected to be a cutaneous infection with Mycobacteria or Tinea corporis. Histopathologically, the skin lesion formed an abscess. A smear revealed a few branched Gram-positive filamentous microorganisms that formed a creamy white colony on a blood agar plate after incubation for 3 days. The colony tested negative on acid-fast bacilli (AFB) staining, but was positive on modified AFB staining. The isolate was confirmed to be N. abscessus by 16S rRNA sequencing analysis. The isolate was susceptible to trimethoprim-sulfamethoxazole, amikacin, cefotaxime and erythromycin but resistant to penicillin. The patient was treated with clarithromycin but subsequently lost to follow-up. To the best of our knowledge, this is the first report of a human cutaneous infection with N. abscessus in Korea.

The Evolving Epidemiology of Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Adults in Crete, Greece, 2009–2016

BACKGROUND: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009–2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). MATERIALS AND METHODS: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ≥2 non-β-lactam antimicrobials. RESULTS: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. CONCLUSION: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

The Evolving Epidemiology of Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Adults in Crete, Greece, 2009–2016

BACKGROUND: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009–2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). MATERIALS AND METHODS: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ≥2 non-β-lactam antimicrobials. RESULTS: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. CONCLUSION: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

Susceptibility of Streptococcus agalactiae to erythromycin and clindamycin in pregnant women in the prenatal screening

Introduction: Group B streptococcus (GBS), or Streptococcus agalactiae, is a bacterium found in normal human microbiota. However, it may cause neonatal pneumonia, sepsis, and meningitis. Genital colonization in pregnant women is associated with a higher risk of preterm birth. The treatment of choice is antibiotic therapy with beta-lactams, but in the case of multidrug-resistance, erythromycin and clindamycin can be used. Methods: This study evaluated bacterial cultures in the period from 2014 to 2015 from a group of 29,875 pregnant women. GBS colonization and resistance to erythromycin and clindamycin were investigated. Results: Positive cultures were found in 26.8% and 26.1% of the samples in 2014 and 2015, respectively. Levels of resistance to erythromycin and clindamycin were, respectively, 2.4% and 5.5% in 2014 and 3.2% and 6.5% in 2015. Conclusion: The investigation of GBS colonization and the evaluation of GBS resistance to erythromycin and clindamycin are of extreme relevance, given the increasing incidence of bacterial resistance, risks of preterm birth. (AU)