RESUMEN
Spread of antimicrobial resistance and virulence factors among Staphylococcus aureus/Staphylococcus argenteus poses a potential public health concern in Myanmar. In this study, a total of 226 clinical isolates of S. aureus (n = 211) and S. argenteus (n = 15) collected in Yangon General Hospital during a two-year period were analyzed for their antimicrobial susceptibility and genetic features. Methicillin-resistant S. aureus (MRSA) accounted for 19% of S. aureus isolates, associated with mostly staphylococcal cassette chromosome mec (SCCmec) type IV, or V. Panton-Valentine leukocidin (PVL) genes were detected in methicillin-susceptible S. aureus (MSSA) at significantly higher rate (39%) than in MRSA (22%). Among MRSA, ST361 (clonal complex [CC] 361), ST772 (CC1), and ST239 (CC8) were frequently identified, while the most common clone in MSSA was ST2990 (CC1), followed by ST121 and CC8 comprising five STs. Novel coagulase gene genotype XVI was identified in four MSSA isolates. All the S. argenteus isolates were assigned to ST2250 and mecA negative, including only one PVL-positive isolate. MSSA and S. argenteus were co-isolated from two patients, while two different MSSA clones were simultaneously identified in eight patients. This study revealed clonal diversity and genetic characteristics of current MRSA/MSSA/S. argenteus clinical isolates in the national tertiary care hospital in Myanmar.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus/genética , Coagulasa/genética , Centros de Atención Terciaria , Mianmar/epidemiología , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/epidemiología , Genotipo , Leucocidinas/genética , Factores de Virulencia/genéticaRESUMEN
Antimicrobial resistance (AMR) is a concern in medical care for children who have high burden of infectious diseases. We investigated the prevalence of bacterial species and their susceptibility to antimicrobials of 1019 clinical isolates from pediatric patients in a tertiary-care hospital in Yangon, Myanmar for one-year period (2020). The most frequently recovered species was Escherichia coli, followed by Klebsiella pneumoniae and Staphylococcus aureus, all of which accounted for 43% of clinical isolates, while 25% of isolates comprised non-fermenter, including Pseudomonas sp. and Acinetobacter sp. Phenotypically determined ESBL (extended-spectrum beta-lactamase)-positive rates in E. coli, K. pneumoniae, and Enterobacter sp. were 82%, 88%, and 65%, respectively. High rates of multiple drug resistance were noted for E. coli (84%), K. pneumoniae (81%), and Acinetobacter sp. (65%), associated with carbapenem resistance in 48%, 42%, and 59% of isolates, respectively. In contrast, S. aureus isolates exhibited low resistance rates (<30%) to most of antimicrobials, with 22% being resistant to oxacillin/cefoxitin. Fluoroquinolone resistance was found in most of bacterial species with different prevalence rates. The present study revealed the current status on prevalence of bacterial species causing infections in pediatric patients in Myanmar, highlighting the significance to monitor AMR among children.
RESUMEN
The spread of multidrug-resistant and virulent Staphylococcus aureus among children is a public health concern, but the actual conditions in Myanmar have not been characterized. In this study, a total of 244 clinical isolates of S. aureus collected from pediatric patients in Yangon Children's Hospital during a 1-year period were analyzed for their drug resistance and genetic features. Methicillin-resistant S. aureus (MRSA) accounted for 19.7% of isolates associated with staphylococcal cassette chromosome mec (SCCmec) type III, IV, or V. Panton-Valentine leukocidin (PVL) genes were detected in 61.5% of all isolates, with a significantly higher prevalence in methicillin-susceptible S. aureus (MSSA; 67.9%) than in MRSA (35.4%) isolates. Sequence type (ST) 239/SCCmec-III was the most common MRSA clone lacking PVL genes, while PVL-positive MRSA belonged to mostly ST361/SCCmec-V and ST772/SCCmec-V. Among MSSA isolates, ST121, ST2990, ST88, and ST1930 were dominant, harboring mostly PVL genes. ST239 MRSA isolates exhibited the highest resistance rates to antimicrobials, and quinolone resistance was found in the dominant MRSA clones (ST239, ST361, and ST772) and some MSSA lineages. The present study revealed the prevalence and clonal diversity of MRSA/MSSA in children in Myanmar in relation to drug resistance and virulence determinants.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Genes Bacterianos/genética , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Pruebas de Sensibilidad Microbiana , Mianmar , Factores de Virulencia/genéticaRESUMEN
BACKGROUND: There is mounting evidence of a high burden of antimicrobial-resistant infections in children in low- and middle-income countries (LMICs). OBJECTIVES: To detect the frequency of ESBL-producing Escherichia coli in clinical specimens from paediatric patients attending Yangon Children's Hospital in Myanmar. METHODS: All children attending Yangon Children's Hospital who had clinical specimens submitted to the hospital diagnostic microbiology laboratory from June 2019 to December 2019 were included in the study. Specimens were processed routinely using standard methods with BD Phoenix used for pathogen identification and susceptibility testing. Presence of ESBLs was determined using the cephalosporin/clavulanate combination disc method with confirmation by PCR. RESULTS: From 3462 specimens submitted to the Microbiology Laboratory, a total of 123 E. coli were isolated. Among them, 100 isolates were phenotypically ESBL producers, 94 (76.4%) of which were confirmed by PCR [82/94 (87%) CTX-M, 72/94 (77%) TEM, 1/94 (1%) SHV]. Most of the ESBL-producing E. coli were isolated from urine samples (52.1%, 49/94) and the majority were from the surgical unit (61.7%, 58/94). Only 34/94 (36%) isolates were susceptible to meropenem. CONCLUSIONS: This study confirms a high proportion of infections caused by ESBL-producing and MDR E. coli in children hospitalized in Yangon, where access to effective second-line antimicrobials is limited.
RESUMEN
In recent years, nosocomial infections due to multidrug resistant Klebsiella pneumoniae strains have been increasing, associated with growing trend of resistance to beta-lactams and fluoroquinolones (FQs) worldwide. In this study, prevalence of beta-lactamase genes and resistance mechanisms to FQ were analyzed in 191 clinical K. pneumoniae isolates derived from respiratory tract infections in a teaching hospital in Yangon, Myanmar. The major extended-spectrum beta-lactamase gene was blaCTX-M, which was detected in 33% of isolates, with CTX-M-15 being dominant. Fourteen isolates (7.3%) harbored carbapenemase genes that were genotyped as blaNDM-1, blaNDM-5, or blaNDM-7. The most common plasmid-mediated quinolone resistance (PMQR) gene was aac6'-Ib-cr (51.8%), followed by qnrB (41.9%), oqxAB (23%), and qnrS (15.2%). In quinolone-resistance determining region of GyrA, eight different types of mutation were identified for FQ-resistant isolates, with double mutations at two positions (S83F, D87A) being most common (54.6%). Isolates with double mutations (three patterns) showed higher minimal inhibitory concentration to levofloxacin (LVX) (≥64 µg/mL) than those with a single mutation. PMQR gene profiles, including aac6'-Ib-cr and any other gene(s), were generally related to higher resistance level to LVX. K. pneumoniae isolates with different profiles of beta-lactamase genes and FQ-resistance determinants were mostly classified into ST15 or its single-locus variant (SLV). The most common NDM gene, blaNDM-5, was detected in ST975 (ST15-SLV) isolates and an ST4000 isolate. The present study revealed the wide spread of FQ-resistant K. pneumoniae clinical isolates acquiring various FQ-resistance determinants and beta-lactamases that were presumably derived from a single clonal lineage in a hospital in Myanmar.
Asunto(s)
Fluoroquinolonas/farmacología , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/genética , Klebsiella pneumoniae/efectos de los fármacos , beta-Lactamasas/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Proteínas Bacterianas/genética , Relación Dosis-Respuesta a Droga , Femenino , Hospitales de Enseñanza , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mianmar , Plásmidos , Prevalencia , Adulto JovenRESUMEN
Panton-Valentine leukocidin (PVL) is a pore-forming toxin encoded by genes on bacteriophages distributed to Staphylococcus aureus, associated with its increased virulence to humans. In this study, molecular epidemiological characteristics were investigated for 239 clinical isolates of S. aureus collected in a tertiary care hospital in Yangon, Myanmar, particularly with regard to methicillin resistance and PVL genes. Methicillin-resistant S. aureus (MRSA) accounted for 13.8% (33/239) and possessed mostly types IV- and V-SCCmec, while types III- and IX-SCCmec were identified in a few isolates. PVL genes were detected in 66.7% and 28.6% in MRSA and methicillin-susceptible S. aureus (MSSA), respectively. Among PVL-positive MRSA, ST772/SCCmec-V isolates (i.e., Bengal Bay clone) were predominant (73%, 16/22), and harbored PVL gene-encoding bacteriophage ΦSa119. Furthermore, two ST8-MRSA-SCCmec-IVa isolates harbored type-I arginine catabolic mobile element and ΦSa2usa: these isolates were considered the USA300 clone first identified in Myanmar. ΦPVL was the most frequent PVL phage among MSSA (56%, 33/59), and distributed to various genotypes, with ST88 and ST121 being dominant. In contrast, ΦSa2usa and ΦSa119 were also detected in MSSA with genotypes other than ST8 or ST772, suggesting the spread of these PVL phages to MSSA. The present study revealed potentially high prevalence of PVL phages among diverse clones of MRSA and MSSA in Myanmar.
Asunto(s)
Toxinas Bacterianas/metabolismo , Bacteriófagos/genética , Exotoxinas/metabolismo , Leucocidinas/metabolismo , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/virología , Meticilina/farmacología , Infecciones Estafilocócicas/microbiología , Antibacterianos/farmacología , Bacteriófagos/metabolismo , Genotipo , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Epidemiología Molecular , Mianmar , Infecciones Estafilocócicas/tratamiento farmacológico , Centros de Atención Terciaria , Factores de Virulencia/genéticaRESUMEN
The dissemination of CMY-type enzymes, one of the plasmid-mediated AmpC beta-lactamases, among Enterobacteriaceae has become an important public health concern. In this study, genetic diversity of CMY beta-lactamase genes was investigated for 50 blaCMY-positive isolates detected from 426 clinical isolates of Escherichia coli in Yangon, Myanmar. CMY genes were differentiated into 9 types, with blaCMY-42 being predominant (22 isolates, 44%), followed by blaCMY-2, blaCMY-6, blaCMY-146, and included three novel types (CMY-156, CMY-158, CMY-159). Among E. coli harboring blaCMY, phylogenetic group D-sequence type (ST)405 and A-ST410 were the most common genotypes, and blaCTX-M-15 was detected in 72% (36/50) of isolates. blaCMY-42 was distributed to phylogenetic groups A, B1, and D E. coli with 11 STs, which included 10 isolates harboring carbapenemase genes (blaNDM-4, blaNDM-5, or blaNDM-7). Phylogenetic analysis of all the blaCMY genes reported to date, including the three novel types in the present study, revealed the presence of at least four distinct genetic groups, that is, CMY-1, CMY-2, CMY-70, and CMY-98 group, showing less than 91% nucleotide sequence identities among different groups. CMY-2 group beta-lactamase genes, which contained by far the largest number of CMY types (89.7%) with extensive diversity, were divided into two clusters (I and II). While eight CMY types identified in the present study were classified into CMY-2 group cluster I, novel type CMY-159 was assigned into CMY-98 group with a Citrobacter freundii strain in Thailand.
Asunto(s)
Antibacterianos/farmacología , Escherichia coli/genética , beta-Lactamasas/genética , Técnicas Bacteriológicas , Escherichia coli/aislamiento & purificación , Humanos , Mianmar , FilogeniaRESUMEN
PURPOSE: Staphylococcus argenteus is a novel emerging species of coagulase-positive staphylococcus that is genetically closely related to Staphylococcus aureus. To elucidate the molecular differences in the virulence factors (staphylocoagulase, protein A, alpha-haemolysin, enterotoxin-like toxin and staphylokinase) between these staphylococcal species, S. argenteus that had recently been isolated in Myanmar (five nasal isolates and four clinical isolates) were analysed. METHODOLOGY: The nucleotide sequences of the virulence factors were determined by PCR and direct sequencing, followed by phylogenetic analysis by mega6 and multiple alignment by clustalw using the published sequence data for S. aureus and S. argenteus. RESULTS: Six S. argenteus isolates belonged to MLST sequence type (ST) 2250, while others belonged to ST4625, ST2198 and ST2854. The novel staphylocoagulase (coa) genotype XIV and the novel coa-XI subtype (XId) were identified in an ST2198 isolate and all other isolates, respectively. Among the S. argenteus isolates, the protein A and alpha-haemolysin genes showed high sequence identity (96-98â% and >99â%, respectively), while lower identity was observed between S. argenteus and S. aureus (88-91â% and 86â%, respectively), with both species showing phylogenetically distinct clusters. Similar findings were found for the staphylococcal enterotoxin (SE)-like toxin genes selw, selx and sely. In contrast, the staphylokinase genes were almost identical between these two species. All of the coa-XId isolates had a CRISPR/Cas locus at the site of orfX without having SCCmec, whereas an ST2198 isolate lacked this locus. CONCLUSION: The primary virulence factors (staphylocoagulase, protein A andalpha-haemolysin) as well as the SE-like toxins of S. argenteus were genetically discriminated from those of S. aureus, revealing the presence of the novel coa-type/subtype (coa-IXd, XIV) in S. argenteus.
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Proteínas Bacterianas/genética , Infecciones Estafilocócicas/microbiología , Staphylococcus/genética , Factores de Virulencia/genética , Adulto , Anciano , Anciano de 80 o más Años , Técnicas de Tipificación Bacteriana , Coagulasa/genética , Femenino , Genotipo , Proteínas Hemolisinas/genética , Humanos , Masculino , Tipificación de Secuencias Multilocus , Mianmar , Filogenia , Proteína Estafilocócica A/genética , Staphylococcus/enzimología , Staphylococcus/aislamiento & purificación , Adulto JovenRESUMEN
The increasing trend of Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases is a global public health concern. In this study, prevalence and molecular characteristics of E. coli harboring ESBL and carbapenemase genes were investigated for 426 isolates derived from various clinical specimens in a teaching hospital in Yangon, Myanmar, for the 1-year period beginning January 2016. A total of 157 isolates (36.9%) were ESBL producers and harbored CTX-M-1 group genes (146 isolates; blaCTX-M-15, blaCTX-M55) or CTX-M-9 group genes (11 isolates; blaCTX-M-14, blaCTX-M-27). Carbapenem resistance was detected in 35 isolates (8.2%), among which 26 isolates had carbapenemase genes encoding NDM-1 (2 isolates), NDM-4 (6 isolates), NDM-5 (14 isolates), NDM-7 (3 isolates), and OXA-181 (2 isolates). blaNDM-5 was identified in phylogenetic groups A, B1, and D isolates belonging to various genotypes (ST101, ST354, ST405, ST410, ST1196) associated with blaTEM-1, blaCTX-M-15, blaOXA-181, blaCMY-2, blaCMY-6, blaCMY-42, qnrB, qnrS, or aac6'-Ib-cr. While two isolates with blaOXA-181 belonged to phylogenetic group A-ST410, one isolate had also blaNDM-5, as well as blaCTX-M-15 and blaCMY-2, and the other harbored blaCMY-42 and aac6'-Ib-cr, showing different resistance patterns. Phylogenetic group B2 isolates examined were classified into mostly ST131 and had solely blaCTX-M-15 or blaCTX-M-27, harboring more virulence factors than other phylogenetic groups. The present study revealed high prevalence of ESBL genes represented by blaCTX-M-15 and dominance of blaNDM-5 among NDM genes, disseminating to various E. coli clones. Notably, carbapenemase gene encoding OXA-181 was first identified in Myanmar, suggesting its spread together with NDM genes.