Phenotypic and molecular characterization of Staphylococcus aureus isolates conducted in nares of psoriatic patients attending a public hospital in Argentina / Caracterización fenotípica y molecular de aislamientos de Staphylococcus aureus portados en narinas de pacientes con psoriasis que concurren a un hospital público en Argentina

Abstract Although Staphylococcus aureus increases its relative abundance in psoriasis when compared with the microbiome of healthy subjects, it is not the most important microorganism underlying this disease. However, there is scant data on the role and molecular features of S. aureus strains in psoriasis; therefore, the aim of this study was to evaluate nasal carriage of this microorganism, its phenotypic and molecular characteristics as well as the impact of host factors on its carriage in psoriatic patients. The presence of S. aureus was analyzed in nasal swabs from 46 healthy volunteers and 50 psoriatic patients by conventional microbiology techniques. Nasal carriage of S. aureus was higher in psoriatic patients than in the control group (37.24% vs 22.98%, respectively), being associated to sex (male), age (adults) and severity of the disease (more frequent in moderate and severe cases). Determination of antibiotic resistance detected 12% of (-lactam resistant isolates, with variable accompanying resistance to macrolides, aminoglycosides and fluoroquinolones. No resistance to rifampicin, vancomycin, mupirocin or trimethoprim/sulfamethoxazole was found. A preliminary molecular characterization of the isolates was performed by PCR amplification of virulence genes. Molecular characterization of the strains did not reveal a predominant strain in psoriatic patients. Although we established host factors related to increased carriage of S. aureus in psoriatic patients, we could not establish the predominance of one type of strain. Genomic and transcriptomic analysis of the isolated strains would be necessary to address this point.

Resumen A pesar de que Staphylococcus aureus incrementa su abundancia relativa en la psoriasis cuando se compara con el microbioma de personas sanas, no es el microorganismo más importante subyacente a la enfermedad. Sin embargo, existen pocos datos sobre el papel y las características moleculares de las cepas de S. aureus en pacientes con psoriasis. Nuestro objetivo fue evaluar la portación nasal de este microorganismo, sus características fenotípicas y moleculares, y el impacto de factores del hospedador sobre dicha portación en estos pacientes. Se analizó la presencia de S. aureus en hisopados nasales de 46 voluntarios sanos y 50 pacientes con psoriasis mediante técnicas microbiológicas convencionales. Se encontró mayor portación en pacientes con psoriasis que en el grupo control (37,24% vs. 22,98%, respectivamente) y esta estuvo asociada al sexo (masculino), la edad (adultos) y la gravedad de la enfermedad (más frecuente en casos moderados a graves). El 12% de los aislamientos de S. aureus mostraron resistencia a betalactámicos, con resistencia acompañante a macrólidos, aminoglucósidos y fluoroquinolonas en grado variable. No se encontró resistencia a rifampicina, vancomicina, mupirocina o trimetroprima/sulfametoxazol. Se realizó una caracterización molecular preliminar de los aislamientos por amplificación de genes de virulencia mediante PCR. Si bien se identificaron factores relacionados con el hospedador que incrementan la portación nasal de S. aureus en pacientes con psoriasis, la caracterización molecular de las cepas no reveló ninguna característica genotípica predominante asociada a esta afección. Se necesitan más estudios genómicos y transcriptómicos para profundizar en esta caracterización.

Air quality of metro system in a northwestern city of China from 2021 to 2022 / 环境与职业医学

Background Most metro system are underground, airtight, with inadequate ventilation and massive gatherings, posing health risks to metro riders. Objective To evaluate air quality of Metro Line 1 in a city, and provide suggestions and basis for preventing harmful factors and protecting the health of passengers. Methods Station halls, station platforms, and metro carriages of Metro Line 1 in a city were monitored in summer (from July to August in 2021) and winter (from January to February in 2022). Six metro stations were selected by stratified sampling. Each station and carriage were monitored for three consecutive days in rush hours (9:00–11:00 and 19:00–21:00) and non-rush hours (11:00–13:00), with the same monitoring frequency. The monitored indicators were physical factors (temperature, relative humidity, wind speed, illumination, and noise), chemical factors (carbon monoxide, carbon dioxide, inhalable particles, formaldehyde, benzene, toluene, xylene, ammonia, and ozone), biological factor (airborne total bacterial count), and radiation factor (radon). The monitoring results were compared by location, time period, and season. Results According to the Hygienic indicators and limits for public places (GB 37488—2019), the selected physical factors did not meet the standard, especially the temperature and relative humidity of station hall and platform, and wind speed and noise of carriage. The results of physical factors varied significantly by location (P<0.05). In summer, the temperature of carriage [M (P25, P75), 23.9 (23.3, 24.6)℃] was the lowest, and the wind speed [0.78 (0.37, 1.11) m·s−1] and noise [76.0 (72.0, 80.3) dB] of carriage were the highest; in winter, the temperatures of station hall and platform were the lowest [16.2 (13.2, 17.2)℃ and 16.2 (13.4, 17.0)℃, respectively], the relative humidity of carriage [26.4% (24.2%, 27.9%)] was the lowest, and the wind speed and noise of carriage were the highest [0.83 (0.47, 1.18) m·s−1 and 74.5 (70.1, 78.3) dB, respectively]. The physical factors varied significantly by time period (P<0.05). In summer, the temperature was the lowest during morning rush hours [24.0 (23.0, 24.8)℃] and non-rush hours [24.2 (23.2, 24.9)℃], and the relative humidity during evening rush hours was the lowest [41.9% (37.0%, 47.8%)]; in winter, the temperature was the lowest during morning and evening rush hours [16.8 (13.4, 19.7)℃ and 16.5 (15.1, 19.4)℃, respectively], the relative humidity during the non-rush period was the lowest [26.8% (24.7%, 28.6%)], and the wind speed during evening rush hours was the highest [0.28 (0.19, 0.51) m·s−1]. All measured chemical factors, biological factor, and radiation factor met the national standard (GB 37488—2019). Conclusion The chemical, biological, and radiative factors are complied with the national standard (GB 37488—2019) except physical factors such as temperature, relative humidity, wind speed, and noise. We suggest that the metro operators make full use of air conditioning system in combination with humidifiers to better regulate temperature and relative humidity, and .arrange working hours reasonably and provide noise-proof earplugs for carriage staff to protect against noise hazard.

Prevalence and Susceptibility of Staphylococcus aureus Nasal Carriage Strains Isolated from Haemodialysis Patients

@#Introduction: Staphylococcus aureus is part of the normal human flora that can commonly be found on the skin and mucous membranes of the nasal area. However, in immunosuppressed patients such as those with kidney failures, colonization can potentially lead to infection. There is a concern of increasing antibiotic resistance in S. aureus. This study aimed to determine the prevalence of S. aureus nasal colonization and its antimicrobial susceptibility among haemodialysis-dependent populations. Methods: A cross-sectional study at the Nephrology Unit, Hospital Canselori Tuanku Mukhriz (HCTM) was conducted among haemodialysis-dependent patients between February 2017 to February 2018. Nasal swabs were obtained and cultured on mannitol salt agar. S. aureus isolates were identified by gram staining, tube coagulase and Deoxyribonuclease (DNase). Cefoxitin disc (30 µg) were used to identified the presence of MRSA (methicillin-resistance S. aureus). The S. aureus colonies were further tested against six antibiotics using Kirby Bauer disc diffusion. Result: A total of 134 patients were recruited. S. aureus isolates were detected from 27 patients (20.1%). All S. aureus were phenotypically identified as methicillin-sensitive S. aureus (MSSA) based on the cefoxitin disc. Teicoplanin and linezolid were the most effective with 100% susceptibility. S. aureus exhibited a high resistance rate towards erythromycin (29.6%). No MRSA was isolated in this study. Conclusion: This study highlighted the high prevalence of S. aureus nasal colonization in haemodialysis patients. Teicoplanin and linezolid were found to be the most effective antibiotics against isolated S. aureus.

Risk factors associated with prolonged nasopharyngeal carriage of SARS-CoV-2 and length of stay among patients admitted to a COVID-19 referral center in Manila, Philippines

Objective@#Prolonged nasopharyngeal carriage of SARS-CoV-2 has been linked to prolonged hospital stay and delayed radiologic recovery. To determine if clinical risk factors are associated with prolonged nasopharyngeal carriage or longer hospital stay, we performed a descriptive analysis of 169 moderate to severe COVID-19 patients admitted at the Philippine General Hospital from March to June 2020.@*Methods@#Length of nasopharyngeal RT-PCR positivity and clinical demographic data were extracted from existing patient records. Chi-square test, Mann-Whitney U test, and regression analysis were performed to describe the association of clinical risk factors with prolonged nasopharyngeal carriage and length of hospital stay.@*Results@#The median duration of carriage was 19 days (IQR 12.0-30.0 days). No comorbidities or inflammatory markers had a statistically significant association with prolonged nasopharyngeal carriage defined as >24 days of nasopharyngeal RT-PCR positivity. Characteristics associated with a statistically significant longer hospital stay included chronic kidney disease stages 3-5, severe disease, and use of empiric antibiotics on admission. Prolonged carriage >24 days, hsCRP, and D-dimer at admission, also had a statistically significant but weak correlation with length of stay.@*Conclusion@#Among patients with moderate disease, comorbidities and inflammatory markers were not associated with prolonged COVID-19 nasopharyngeal carriage. Prolonged nasopharyngeal carriage >24 days was associated with longer hospital stay, while D-dimer and hsCRP levels at admission, also had statistically significant but small effects on increasing the hospital length of stay.

Prevalence of Sexually Transmitted Chlamydia trachomatis and Neisseria gonorrhoeae Infections in an Asymptomatic Population in Dakar, Senegal

Introduction: Sexually transmitted infections (STIs) represent a major public health problem. Chlamydia trachomatis and Neisseria gonorrhoeae infections are often asymptomatic, thus leading to a high risk of transmission in subjects with risky behaviors. The objective of this study was to determine the prevalence of these 2 pathogens in an asymptomatic population. Methodology: A retrospective, cross-sectional, descriptive study was conducted in the medical biology laboratory of the Pasteur Institute of Dakar over a period of 23 months in asymptomatic patients who were seen as part of a travel check-up. A first-draft urine sample was collected and tested for C. trachomatis and N. gonorrhoeae by molecular biology techniques. Data entry and statistical analysis were performed by Excel 2010 and SPSS 2.0 respectively. Results: A total of 5012 patients were included and the overall prevalence of STIs related to these 2 pathogens was 3.8% (194/5012). The prevalences of C. trachomatis and N. gonorrhoeae were 2.7% (137/5012) and 1.0% (55/5012), respectively. The age group most affected was [20-29 years] with 58.4% (80/137; p=0.0001) for C. trachomatis and 45.5% (25/55; p=0.471) for N. gonorrhoeae. Co-infection with these two germs was observed in 0.3% (18; p=0.001) of patients. Conclusion: STIs with C. trachomatis and/or N. gonorrhoeae can be asymptomatic and continue the chain of transmission. Thus, for a better prevention of STIs due to these pathogens, it is important to screen, educate and sensitize the populations considered at risk.

Portación nasal de Staphylococcus aureus en el personal de salud de áreas críticas de un Hospital Pediátrico durante julio-setiembre 2018 / Nasal carriage of Staphylococcus aureus in health personnel in critical areas of a Pediatric Hospital during July-September 2018 / Transporte nasal de Staphylococcus aureus em profissionais de saúde em áreas críticas de um Hospital Pediátrico durante julho-setembro de 2018

Las infecciones intrahospitalarias (IIH) son causa de elevada morbimortalidad y representan un problema sanitario importante. El personal de salud es reservorio y potencial transmisor de los agentes etiológicos de las mismas. S. aureus es uno de los microorganismos implicados, por lo tanto es importante conocer la frecuencia de portación en el personal de salud y establecer el perfil de susceptibilidad antimicrobiana para contribuir con la elaboración de medidas de prevención incluyendo actividades educativas. Objetivo: Conocer la frecuencia de portación de S. aureus, distribución y antibiotipos de las cepas presentes en el personal sanitario del Hospital Pediátrico de Referencia (HPR). Materiales y métodos: Se realizó un estudio descriptivo durante el periodo julio-setiembre del año 2018. Se incluyeron muestras de hisopados nasales de trabajadores de la salud de distintas áreas de internación que consintieron participar en el estudio. Se excluyeron aquellos que recibieron antibióticos dentro de los 3 meses previos al estudio. Las muestras fueron sembradas en agar sangre ovina al 5% (ASO) y se incubaron a 35-37ºC en aerobiosis por 24-48 horas. La identificación de las colonias sospechosas de Staphylococcus aureus por métodos convencionales y MALDI-TOF. El patrón de resistencia antimicrobiana de S. aureus se detectó por disco-difusión. En los cultivos resistentes a meticilina (SAMR) se determinó la presencia del gen mecA y se realizó la tipificación del SCCmec por pruebas de reacción en cadena de polimerasa. Resultados: Se obtuvieron 225 hisopados a partir de 225 trabajadores, presentaron desarrollo 212. En 49 se recuperaron cultivos de S. aureus. Correspondieron a SAMR 11 de las 49 cepas, todas portaban el gen mecA. Hubo predominio en el personal de enfermería (7/11), en los servicios de hemato-oncología (3/11) y cuidados intensivos neonatales (4/11). Asociaron resistencia a macrólidos y clindamicina 8 de 11 aislamientos SAMR, a gentamicina 2 y a mupirocina uno. El SCCmec más frecuentemente identificado fue el tipo IV (7/11). Conclusiones: Los resultados muestran la presencia de cepas SAMR entre el personal de salud del CHPR y aportan información complementaria para efectuar prevención y control de las IIH, actuando sobre todo en el personal de salud encargado de la atención de pacientes susceptibles.

Hospital-acquired infections (IIH) are a cause of high morbidity and mortality and represent a major health problem. Health personnel are reservoirs and potential transmitters of their etiological agents. S. aureus is one of the microorganisms involved, therefore it is important to know the frequency of carriage in health personnel and establish the antimicrobial susceptibility profile to contribute to the development of prevention measures, including educational activities. Objective: To know the frequency of carriage of S. aureus, distribution and antibiotypes of the strains present in the health personnel of the Reference Pediatric Hospital (HPR). Materials and methods: A descriptive study was carried out during the period July-September 2018. Nasal swab samples from health workers from different hospitalization areas who agreed to participate in the study were included. Those who received antibiotics within 3 months prior to the study were excluded. The samples were seeded in 5% sheep blood agar (ASO) and incubated at 35-37ºC in aerobiosis for 24-48 hours. Identification of suspicious Staphylococcus aureus colonies by conventional methods and MALDI-TOF. The antimicrobial resistance pattern of S. aureus was detected by disc diffusion. In methicillin-resistant cultures (MRSA), the presence of the mecA gene was determined and SCCmec was typified by polymerase chain reaction tests. Results: 225 swabs were obtained from 225 workers, 212 showed development. S. aureus cultures were recovered from 49. 11 of the 49 strains corresponded to MRSA, all of them carried the mecA gene. There was a predominance in the nursing staff (7/11), in the hematology-oncology services (3/11) and neonatal intensive care (4/11). They associated resistance to macrolides and clindamycin in 8 of 11 MRSA isolates, 2 to gentamicin, and 1 to mupirocin. The most frequently identified SCCmec was type IV (7/11). Conclusions: The results show the presence of MRSA strains among the health personnel of the CHPR and provide complementary information to carry out prevention and control of IIH, acting especially on the health personnel in charge of the care of susceptible patients.

As infecções hospitalares (HII) são causa de alta morbidade e mortalidade e representam um importante problema de saúde. Os profissionais de saúde são reservatórios e potenciais transmissores de seus agentes etiológicos. O S. aureus é um dos micro-organismos envolvidos, por isso é importante conhecer a frequência de portadores em profissionais de saúde e estabelecer o perfil de suscetibilidade antimicrobiana para contribuir no desenvolvimento de medidas de prevenção incluindo atividades educativas. Objetivo: Conhecer a frequência de portadores de S. aureus, distribuição e antibiótipos das cepas presentes no pessoal de saúde do Hospital Pediátrico de Referência (HPR). Materiais e métodos: Foi realizado um estudo descritivo durante o período de julho a setembro de 2018. Foram incluídas amostras de swab nasal de profissionais de saúde de diferentes áreas de internação que concordaram em participar do estudo. Aqueles que receberam antibióticos nos 3 meses anteriores ao estudo foram excluídos. As amostras foram semeadas em 5% de ágar sangue de carneiro (ASO) e incubadas a 35-37ºC em aerobiose por 24-48 horas. Identificação de colônias suspeitas de Staphylococcus aureus por métodos convencionais e MALDI-TOF. O padrão de resistência antimicrobiana de S. aureus foi detectado por difusão em disco. Em culturas resistentes à meticilina (MRSA), a presença do gene mecA foi determinada e SCCmec foi tipificado por testes de reação em cadeia da polimerase. Resultados: 225 swabs foram obtidos de 225 trabalhadores, 212 apresentaram desenvolvimento. Culturas de S. aureus foram recuperadas de 49. 11 das 49 cepas correspondiam a MRSA, todas carregavam o gene mecA. Houve predominância na equipe de enfermagem (7/11), nos serviços de hematologia-oncologia (3/11) e de terapia intensiva neonatal (4/11). Eles associaram resistência a macrolídeos e clindamicina em 8 de 11 isolados de MRSA, 2 à gentamicina e 1 à mupirocina. O SCCmec mais frequentemente identificado foi o tipo IV (7/11). Conclusões: Os resultados mostram a presença de cepas de MRSA entre os profissionais de saúde do CHPR e fornecem informações complementares para realizar a prevenção e controle da HII, atuando principalmente sobre os profissionais de saúde responsáveis ​​pelo atendimento de pacientes suscetíveis.

Biomechanical Characteristics of the Knee Joint During Single-Leg Landing of Soldiers and its Relationship with Isokinetic Muscle Strength / 医用生物力学

Objective To analyze the impact of soldiers’ single-leg landing with load carriage on knee joint, and investigate its relationship with muscle strength, so as to provide references for daily load carriage training. Methods A total of 12 soldiers were required to perform single-leg landing from the 30 cm height without load carriage and with 15 kg load carriage,respectively.The kinematic and kinetic parameters were collected using Vicon motion capture system and AMTI force platform. The surface electromyography (sEMG) of anterior and posterior thigh muscles were also collected simultaneously, and the isokinetic strength during knee flexion and extension was tested. Results Compared with landing without load carriage, knee flexion angle and joint reaction force significantly increased during landing with 15 kg load carriage (P0.05). There was a significant negative correlation between peak moment of knee extension and vertical ground reaction force during single-leg landing without load carriage (P0.05). Conclusions Knee flexion angle and joint reaction force significantly increase during single-leg landing with 15 kg load carriage, the activation of anterior and posterior thigh muscles can relieved the ground reaction force during landing, and muscle strength plays some role in preventing landing injury.

Identification of the nasopharyngeal carriage of Neisseria meningitidis by 16S rRNA Gene sequencing in asymptomatic adolescents and young adults in Cartagena, Colombia (2019-2020)

Abstract The bacterium Neisseria meningitidis, a strictly human pathogen, can cause meningitis, meningococcemia, sepsis, and death; repeatedly it scause outbreaks around the world. The frequency of asymptomatic carriage is often high in adolescents and young adults, increasing the invasive meningococcal disease risk and likelihood of transmission. However, detailed analyses of meningococcal carriage in this population in Colombia, particularly in coastal areas, are lacking. In this study, the prevalence and characteristics of Neisseria meningitidis carriage were evaluated in asymptomatic adolescents and young adults (11-25 years old) in Cartagena, Colombia. Oropharynx samples were collected from participants between August and December 2019. The phenotypic identification of bacteria was performed by conventional methods and biochemical testing. Molecular identification to the species level was performed by 16S rRNA gene sequencing. In total, 12 of 648 samples were positive for Neisseria meningitidis by 16S rRNA sequencing, indicating a prevalence of 1.9%. Isolates were classified into four invasive serogroups (A, B, C, and W) by a comparative sequence analysis of the ribosomal gene. Despite the occurrence of meningococcal disease in Cartagena city in the last several years, the frequency of oropharyngeal carriage in adolescents and young adults was low. Serogroup A had not been previously reported in nasopharyngeal samples in Colombia. This is the first report of Neisseria meningitidis on the Colombian Caribbean coast based on 16S rRNA sequencing and is expected to guide the development of vaccination and follow-up strategies.

Post-antibiotic era in hemodialysis? Two case reports of simultaneous colonization and bacteremia by multidrug-resistant bacteria / Era pós-antibiótica em hemodiálise? Relato de dois casos de colonização simultânea e bacteremia por bactérias multirresistentes

ABSTRACT The emergence of resistance mechanisms not only limits the therapeutic options for common bacterial infections but also worsens the prognosis in patients who have conditions that increase the risk of bacterial infections. Thus, the effectiveness of important medical advances that seek to improve the quality of life of patients with chronic diseases is threatened. We report the simultaneous colonization and bacteremia by multidrug-resistant bacteria in two hemodialysis patients. The first patient was colonized by carbapenem- and colistin-resistant Klebsiella pneumoniae, carbapenem-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA). The patient had a bacteremia by MRSA, and molecular typing methods confirmed the colonizing isolate was the same strain that caused infection. The second case is of a patient colonized by extended-spectrum beta-lactamases (ESBL)-producing Escherichia coli and carbapenem-resistant Pseudomonas aeruginosa. During the follow-up period, the patient presented three episodes of bacteremia, one of these caused by ESBL-producing E. coli. Molecular methods confirmed colonization by the same clone of ESBL-producing E. coli at two time points, but with a different genetic pattern to the strain isolated from the blood culture. Colonization by multidrug-resistant bacteria allows not only the spread of these microorganisms, but also increases the subsequent risk of infections with limited treatments options. In addition to infection control measures, it is important to establish policies for the prudent use of antibiotics in dialysis units.

RESUMO O surgimento de mecanismos de resistência não apenas limita as opções terapêuticas para infecções bacterianas comuns, mas também piora o prognóstico em indivíduos com condições que aumentam o risco de infecções bacterianas. Assim, a eficácia de importantes avanços médicos que buscam melhorar a qualidade de vida de pacientes com doenças crônicas está ameaçada. Relatamos a colonização e bacteremia simultâneas por bactérias multirresistentes em dois pacientes em hemodiálise. O primeiro paciente foi colonizado por Klebsiella pneumoniae resistente a carbapenem e colistina, Pseudomonas aeruginosa resistente a carbapenem e Staphylococcus aureus resistente a meticilina (MRSA). O paciente apresentou bacteremia por MRSA, e os métodos de tipagem molecular confirmaram que o isolado colonizador era a mesma cepa que estava causando infecção. O segundo caso é de um paciente colonizado por Escherichia coli produtora de beta-lactamases de espectro estendido (ESBL) e Pseudomonas aeruginosa resistente ao carbapenem. Durante o período de seguimento, o paciente apresentou três episódios de bacteremia, um deles causado por E. coli produtora de ESBL. Os métodos moleculares confirmaram a colonização pelo mesmo clone de E. coli produtora de ESBL em dois momentos, mas com um padrão genético diferente da cepa isolada da hemocultura. A colonização por bactérias multirresistentes aumenta o potencial não apenas da disseminação desses microrganismos, mas também do risco subsequente de infecções com opções limitadas de tratamentos. Além das medidas de controle de infecção, é importante estabelecer políticas para o uso prudente de antibióticos nas unidades de diálise.

Portación nasal de Staphylococcus aureus en trabajadores de la salud de dos hospitales de la ciudad de Bahía Blanca, Argentina / Staphylococcus aureus nasal carriage in health care workers at two hospitals in Bahía Blanca city, Argentina / Carreamento nasal de Staphylococcus aureus em profissionais da saúde de dois hospitais da cidade de Bahía Blanca, Argentina

Resumen La portación nasal de Staphylococcus aureus representa un riesgo considerable para infecciones tanto nosocomiales como comunitarias. El objetivo del trabajo fue investigar la prevalencia de portación nasal de S. aureus sensibles (SAMS) y resistentes a meticilina (SAMR) en trabajadores de la salud, determinar su asociación con factores epidemiológicos y sus patrones de resistencia a los antimicrobianos. Se tomaron 152 muestras nasales de personal de dos hospitales de la ciudad de Bahía Blanca (Argentina). Los aislados de S. aureus se identificaron por métodos convencionales y por el sistema automatizado BD PhoenixTM 100. La prevalencia de portación nasal de S. aureus fue de 32,2% y, de SAMR, de 12,2%. La frecuencia de portación en el personal de laboratorio (58,8%) resultó estadísticamente significativa. Los aislados fueron sensibles a trimetoprima-sulfametoxazol, cloranfenicol, rifampicina, fluoroquinolonas y vancomicina. Estos datos alertan sobre la necesidad de identificar portadores de S. aureus e implementar estrategias que controlen una potencial diseminación de estos microorganismos.

Abstract The nasal carriage of Staphylococcus aureus represents a considerable risk for both nosocomial and community infections. The objective of this work was to investigate the prevalence of nasal carriage of both methicilin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) in health workers, to determine their association with epidemiological factors and their patterns of antimicrobial resistance. One hundred and fifty-two nasal samples were taken from personnel from two hospitals in the Bahía Blanca city (Argentina). The S. aureus isolates were identified by conventional methods and by the automated BD PhoenixTM 100 system. The prevalence of S. aureus nasal carriage was 32.2% and that of MRSA, 12.2%. The frequency of carrying deterin laboratory personnel was statistically significant (58.8%). The isolates were susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, rifampin, fluoroquinolones and vancomycin. These data warn of the need to identify S. aureus carriers and implement strategies that control the potential spread of these microorganisms.

Resumo O carreamento nasal de Staphylococcus aureus representa um risco considerável para infecções tanto nosocomiais quanto comunitárias. O objetivo do trabalho foi investigar a prevalência de carreamento nasal de S. aureus sensíveis (SAMS) e resistentes à meticilina (SARM) em profissionais da saúde; determinar sua associação com fatores epidemiológicos e seus padrões de resistência aos antimicrobianos. Foram coletadas 152 amostras nasais de funcionários de dois hospitais da cidade de Bahía Blanca (Argentina). Os isolados de S. aureus foram identificados por métodos convencionais e pelo sistema automatizado BD PhoenixTM 100. A prevalência de carreamento nasal de S. aureus foi de 32,2% e a de SARM, de 12,2%. A frequência de carreamento no pessoal do laboratório foi estatisticamente significativa (58,8%). Os isolados foram sensíveis a trimetoprim-sulfametoxazol, cloranfenicol, rifampicina, fluoroquinolonas e vancomicina. Esses dados alertam para a necessidade de identificar portadores de S. aureus e implementar estratégias que controlem a propagação potencial desses microrganismos.

Assessment of Pathogenicity of Community-Acquired MRSA Isolates in Mice-Induced Peritonitis

@#Introduction: Methicillin-Resistance Staphylococcus aureus (MRSA) is known as a major nosocomial pathogen in healthcare. However, it has now spread in the community known as community-acquired MRSA (CA-MRSA). Thus, the survival and pathogenicity of CA-MRSA isolates were assessed using in vivo peritonitis model with comparison to ATCC-MRSA. Two CA-MRSA isolates; CA-MRSA1 and CA-MRSA2 that were isolated from healthy population, were studied and compared. Methods: Mice were assigned into 4 groups and injected intraperitoneally with ATCC-MRSA, CA-MRSA1 or CA-MRSA2, respectively. Sterile Dulbecco’s Phosphate-Buffered Saline (DPBS) represents negative control. Mice were observed twice daily, 0-72 hours of post-infection. Any signs of distress were recorded for severity score and survival analyses. Mice were euthanised at 72 hours post-inoculation or by referring to the Peritonitis Severity Scoring (PSS) system. Organs of interest, peritoneal lavage and abscess were processed for bacterial counts. Tissue samples were analysed for histopathological scores. Results: All mice inoculated with MRSA showed clear signs of illness with peritonitis symptoms of p<0.001 and comparable PSS scores were recorded in all infected mice groups. Intraperitoneal injection of lethal dose of MRSA resulted in significant death of ATCC-MRSA (p<0.05) and CA-MRSA-infected mice (p<0.01), compared to the un-infected. Bacterial burden was significantly high in all samples harvested from mice challenged with CA-MRSA2 compared to ATCC-MRSA except in abscess and lung. Significant liver necrosis and spleen inflammation were observed in CA-MRSA1, and lung inflammation in ATCC-MRSA-infected mice. Conclusion: Nasal carriage CA-MRSA isolates from a healthy population has the potential to cause peritonitis with comparable severity as ATCC-MRSA.

Characteristics of Klebsiella pneumoniae Isolates from Stool Samples of Patients with Liver Abscess Caused by Hypervirulent K. pneumoniae

Risk factors associated with prolonged Nasopharyngeal carriage of SARS-CoV-2 and length of stay among patients admitted to a COVID-19 referral center in Manila, Philippines

Objective@#Prolonged nasopharyngeal carriage of SARS-CoV-2 has been linked to prolonged hospital stay and delayed radiologic recovery. To determine if clinical risk factors are associated with prolonged nasopharyngeal carriage or longer hospital stay, we performed a descriptive analysis of 169 moderate to severe COVID-19 patients admitted at the Philippine General Hospital from March to June 2020. @*Methods@#Length of nasopharyngeal RT-PCR positivity and clinical demographic data were extracted from existing patient records. Chi-square test, Mann-Whitney U test, and regression analysis were performed to describe the association of clinical risk factors with prolonged nasopharyngeal carriage and length of hospital stay. @*Results@#The median duration of carriage was 19 days (IQR 12.0-30.0 days). No comorbidities or inflammatory markers had a statistically significant association with prolonged nasopharyngeal carriage defined as >24 days of nasopharyngeal RT-PCR positivity. Characteristics associated with a statistically significant longer hospital stay included chronic kidney disease stages 3-5, severe disease, and use of empiric antibiotics on admission. Prolonged carriage >24 days, hsCRP, and D-dimer at admission, also had a statistically significant but weak correlation with length of stay. @*Conclusion@#Among patients with moderate disease, comorbidities and inflammatory markers were not associated with prolonged COVID-19 nasopharyngeal carriage. Prolonged nasopharyngeal carriage >24 days was associated with longer hospital stay, while D-dimer and hsCRP levels at admission, also had statistically significant but small effects on increasing the hospital length of stay

Oral Candida Carriage Including Speciation, Biofilm Production And Correlation With Occurrence Of Dental Caries In Student Population

The study was done to establish oral carriage of Candida, speciation, assay biofilm production and correlate the oral Candida carriage with occurrence of dental caries in students. Swab samples from oral cavity were collected from 206 students and were cultured for yeasts. Isolated yeasts were identified and detected for Biofilm production. Results:Overall Candida carriage was found in 90 of the 206 students (75 with caries). The rate of Candida carriage in students with caries (64%) was significantly higher as compared to overall carriage in students (43.7%). Atotal of 123 Candida strains were isolated including C albicans (63%), C tropicalis (23 %), C. parapsilosis (6 %), C. glabrata (4 %) and C. krusei (4 %). Biofilm production by C albicans was less frequent (42. 85%) than that by non-C albicans (63.33 %). and was significantly higher in students with caries than from without caries. Conclusion:We found a significant risk of dental caries with oral Candida carriage rates in student population. Candida albicans was the most common species isolated. Biofilm production was implicated in Candida virulence and was more important for non- C.albicans than C.albicans strains to establish infections.

Fecal carriage of carbapenem resistant Enterobacteriaceae among the intensive care unit patients

Background: The war against multidrug-resistant bacteria is challenging and of global concern. Hospitals are increasingly plagued by resistant gram negative pathogens. Bacteria of the family Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae are part of the normal human intestinal flora but are also often responsible for community- and healthcare-associated infections. These bacteria are prone to acquiring resistance genes.Methods: Rectal swabs/swabs from the peri-anal area of the patients who were admitted in the Intensive Care Unit (ICU) of the accident and emergency department of this teaching hospital. Swabs were collected first on day 1 of admission, then day 4, and thereafter weekly during the period of stay in the ICU. All the swabs were immediately inoculated into trypticase soy broth with one 10μg  meropenem disc and were incubated overnight at 35±2ºC, ambient air. Next day, the broth was vortexed, and then sub-cultured onto a MacConkey agar plate. On the third day, MacConkey agar plates were examined for lactose fermenting (pink-coloured) colonies. The representative isolated colonies were subjected to conventional antimicrobial susceptibility testing by the Kirby Bauer Disc diffusion method following the CLSI guidelines to know the susceptibility to carbapenem and other antimicrobial agents. Carbapenemase production was done by a Modified Hodge Test (MHT) and Imipenem-EDTA test.Results: Out of 89 patients, carbapenem resistant Klebsiella pneumoniae and E. coli isolates were recovered from 35 (39.3%) patients i.e. Klebsiella pneumoniae isolates from fifteen patients and carbapenem resistant E. coli isolates from twenty patients. Prevalence of carbapenemase producing isolates was found to be 1.42%.  Conclusions: Surveillance for CRE can definitely help reduce rates of healthcare associated infections.

Prevalence and Antibiotic Susceptibility of Salmonella Species among Food Handlers in Khartoum- State (Sudan)

Aims/Objectives: To screen the prevalence of Salmonella fecal carriage among healthy foodhandlers and to identify the common species of Salmonella among study population and its antibacterial susceptibility in Khartoum state by taking stool samples. Study Design: Cross-sectional study. Place and Duration of Study: Khartoum state, Sudan, from January 2009 to December 2009. Methodology: Stool samples were collected, processed and cultured on suitable bacterial culture media. Presence of colonies resembling (non-lactose fermenting) Salmonella species were further studied to identify the bacterium by using appropriate biochemical tests.Confirmation and serotyping of isolates were done by using Salmonella antisera. Antibacterial susceptibility test for common antibacterial drugs were also studied. Results: A total of 387 stool samples collected from apparently healthy food handlers werestudied. Salmonella fecal carriage among food handlers was 17 (4.4%) and the highest prevalence was noted in Umbada locality (5.1%). Salmonella Paratyphi B was the commonest 14 (3.6%), followed by Salmonella Typhi 2(0.5%) and Salmonella Cholerasuis 1 (0.3%). Our study revealed that 141 (36.4%) of food handlers were illiterate, 29 (7.5%) werepreschool, 134 (34.6%) were elementary school graduates 68 (17.6%) and 15 (3.9%) university graduates. Forty two (10.9%) of the studied cases mentioned that, they sometimes wash their hands by soap after defecation, while, 9 (2.3%) never washed theirhands. The study also, revealed that 3 (17.6%) of positive food handlers have had history ofprevious typhoid or gastroenteritis. The study demonstrated that Salmonella species isolated were sensitive to co-trimoxazole, ciprofloxacin, chloramphenicol, tetracycline, amoxicillin/ clavulanic acid, ceftriaxone and cefuroxime. Conclusion: This study demonstrated the presence of considerable number of Salmonella fecal carriage among food handlers in Khartoum state. Most of them were illiterate and had poor compliance of hand washing after toilet use. Study also revealed that isolated Salmonella species were highly susceptibility to the common first line antibiotics used in Sudan.

Resistance pattern of methicillin resistant Staphylococcus aureus among nasal isolates of HIV infected patients in a tertiary care hospital

Background: Patients infected with HIV have an increased risk of nasal Staphylococcus aureus carriage as well as consecutive staphylococcal infections and is a major reservoir for MRSA which is potential risk factors for community acquired MRSA. Knowing the Nasal carriage status of Staphylococcus aureus and their Antibiogram will be beneficial for effective management of these patients.Methods: Nasal swab sample were collected from all the participants and processed for culture and identification of Staphylococcus aureus and their antimicrobial sensitivity. All the Staphylococcus aureus isolates were tested for Methicillin resistance by Oxacillin screen agar test, cefoxitin disc diffusion test and further confirmed by mecA gene PCR.Results: In this study out of 220 HIV seropositive patients, 43.64% isolates were confirmed to be S. aureus, 18.75% MRSA and 81.25% were MSSA. Cefoxitin disc diffusion showed 100% specificity (95% CI; 97.05%-100.00%), 100% sensitivity (95% CI; 83.89-100.00%) and 100% accuracy (95% CI; 97.47% to 100.00%) while comparing with gold standard mecA gene PCR. Among the nasal carriers; males (60%) ware dominant on females (40%). 31-50 years age group was strongly associated with MRSA nasal carriage. None of the isolates were resistant against lenozolid, teicoplanin and vancomycin while ampicillin (75%), ciprofloxacin (62.5%), clindamycin (59.38%) and cotrimoxazole (53.13%) showed increased resistance against S. aureus nasal carriage.Conclusions: Resistance among HIV positive persons for all antibiotics showed statistically significant while compared to control group. Cefoxitin disc diffusion can be used as surrogate agent for mecA gene detection.

Carriage prevalence and drug resistance profile of MRSA and MSSA strains isolated from newborns / 中华疾病控制杂志

Objective To determine the carriage prevalence and antibiotics resistance profile of methicillin-resistant staphylococcus aureus(MRSA) and methicillin-sensitive staphylococcus aureus(MSSA) strains isolated from newborns. Methods A cross-sectional study was conducted in two hospitals in Shenzhen from August to November 2015. Cotton swab samples were collected from 1834 newborns. Staphylococcus aureus was identified by general laboratory tests, and antimicrobial-susceptibility profiles was tested. Results In total, 3.27% (60/1 834) Staphylococcus aureus (SA) strains were isolated, including 0.82% (15/1 834) MRSA and 2.45% (45/1 834) MSSA. Most MRSA and MSSA strains were resistant to penicillin and erythromycin but less than 10% strains resistant to linezolid. Drugs resistance rates of MRSA to erythromycin, moxifloxacin and clindamycin were all higher than that of MSSA (all P<0.05). The multidrug-resistant risk of MRSA (80.00%) was 12.36 times higher than that of MSSA (24.44%). Conclusions Multidrug-resistant SA especially MRSA strains isolated from newborns had the higher prevalence, the drugs resistance rate of MRSA strains was more serious than that of MSSA.

Multidrug-resistant Enterobacteriaceae colonising the gut of adult rural population in South India

Background: Multidrug-resistant (MDR) colonisers act as a reservoir for transmission of antibiotic resistance and are a source of infection. Exposure to antibiotics by the commensal flora renders them resistant. Antibiotic consumption and hospitalisation are two major factors influencing this. We studied, antibiotic-resistant bacteria colonising rural adult population who had restricted access to health care and presumably had low consumption of antibiotics. Aim: Detection of multidrug resistance genes of extended spectrum ?-lactamase (ESBL-CTX-M), AmpC ?-Lactamase (CIT), Klebsiella pneumoniae carbapenemase (KPC) and New Delhi Metallo ?-lactamase (NDM) in Enterobacteriaceae colonising the gut of adult population in a South Indian rural community. Methodology: Faecal samples of 154 healthy volunteers were screened for Enterobacteriaceae resistant to commonly used antibiotics by standard methods, followed by phenotypic detection of ESBL by double disk synergy method, AmpC by spot inoculation and carbapenemases by imipenem and ethylenediaminetetraacetic acid + imipenem combined E-test strips and modified Hodge test. Polymerase chain reaction was done to detect blaCTX-M,blaCIT,blaKPC-1 and blaNDM-1 genes coding for ESBL, AmpC, KPC and NDM, respectively. Results: Colonisation rate of enteric bacteria with MDR genes in the community was 30.1%. However, phenotypically, only ESBL (3.2%) and NDM (0.65%) were detected. While the genes coding for ESBL, AmpC and NDM were detected in 35.6%, 17.8% and 4.4% of the MDR isolates, respectively. Conclusions: Carriage of MDR strains with a potential to express multidrug resistance poses a threat of dissemination in the community. Awareness for restricted use of antibiotics and proper sanitation can contain the spread of resistant bacteria.

Effect of lower-limb dominance and non-dominance shuttle runs under load carriage on the balance responses in young cadets / 中国应用生理学杂志

OBJECTIVE@#This test was designed to evaluate the effect of lower-limb dominance and non-dominance shuttle runs under load carriage during different exercise load at the same exercise intensity on the balance responses.@*METHODS@#Ten healthy young males were joined in this experiment, they were (20.80±2.04) years old and (173.99±2.87) cm tall. In a randomized cross-over design, they performed four times shuttle runs under unilateral load carriage:20 m×5 at dominant side, 20 m×5 at non-dominant side, 20 m×10 at dominant side, 20 m×10 at non-dominant side respectively. Balance abilities were evaluated immediately and 20 minute post-exercise respectively, and R-R interval was recorded.@*RESULTS@#The HR, EPOC and TRIMP for all exercise load were increased significantly after shuttle runs compared to rest (0.05), which showed symmetrical change. In addition, during 20 minute recovery, the balance ability for all exercise load was returned to the rest value (>0.05).@*CONCLUSIONS@#The shuttle runs could impair the trunk control ability immediately post-exercise, the magnitude of mediolateral movement was increased as the exercise load increased. The changes of balance responses were similar between the dominant and the non-dominant side, the dominant and the non-dominant side might show cross-effects.