Analysis of drug resistance and related drug resistance genes of Staphylococcus aureus / 中国中西医结合急救杂志

Objective To investigate the drug resistance and the distribution situation of the related drug resistant genes in Staphylococcus aureus (SA), and to provide a basis for the clinical rational use of antibiotics and the hospital control of infection. Methods A total of 135 strains of SA were collected from the Second Affiliated Hospital of Baotou Medical College during January to December 2017. BD Phoenix TM-100 automatic microorganism identification and drug sensitivity systems and K-B agar diffusion method were used to identify SA colony and analyze its drug susceptibility; the related drug resistant genes were detected by polymerase chain reaction (PCR). Results Among 135 strains of SA, 16 (11.9%) methicillin-resistant SA (MRSA) and 119 (88.1%) methicillin-sensitive SA (MSSA) were detected. In the 14 strains of MRSA, the resistance rates to ampicillin, penicillin and erythromycin were high (91.9%, 91.1% and 64.4%, respectively), and no vancomycin, teicoplanin and linezolid-resistant strains were found. Additionally, the resistance rates of MRSA to ciprofloxacin were significantly higher than that of MSSA [31.3% (5/16) vs. 5.0% (6/119), P < 0.05]. Among 135 strains of SA, the detection rates of mecA, aac(6')/aph(2"), erm(A), erm(B), erm(C), and tetM were 4.4% (6/135), 10.4% (14/135), 0.7% (1/135), 27.4% (37/135), 31.4% (46/135) and 0.7% (1/135), respectively. In MRSA, the detection rates of mecA [37.5% (6/16) vs. 0 (0/119)], aac(6')/aph(2") [31.3% (5/16) vs. 7.6% (9/119)], and ermB [31.3% (5/16) vs. 26.9% (32/119)] were significantly higher than those in MSSA. It is noteworthy that the detection rate of mecA in MRSA was only 37.5% (6/16). Conclusions The MRSA detection rate of our hospital was below the national average level. The detection rates of resistance genes mecA, aac(6')/aph(2") and ermB were higher, which may be an important cause of drug resistance. Moreover, the detection of MRSA by mecA alone may lead to missed diagnosis, that should be paid attention to.

Antimicrobial Resistance of Staphylococcus aureus in Our Hospital over the Last 10 Years / 中国医科大学学报

Objective To retrospectively analyze the clinical distribution and changes in antimicrobial resistance profiles of Staphylococcus aureus (S. aureus). Methods We collected clinical specimens of S. aureus from The First Hospital of China Medical University. The Vitek-2 and BD Phoenix 100 were performed for bacterial identification and drug sensitivity tests,and WHONET 5.6 was used to analyze the data. Results From 2007 to 2016,there were 3 377 unrepeatable strains of S. aureus,including 1 705 that were methicillin resistant S. aureus (MRSA). The isolation rate of S. aureus was 9.4 ％ and of these,50.5 ％ were MRSA. There were 776 S. aureus specimens from outpatients or the emergency department,including 16.8 ％ MRSA,and 2 011 S. aureus from inpatient departments,including 60.2 ％ MRSA. The main sources of specimens were sputum (41.8 ％),pus (17.9 ％),and body secretions (17.5 ％). The average resistance rates of MRSA for erythromycin,ofloxacin,ciprofloxacin,gentamycin,and tetracycline were higher than 75.0 ％. The average resistance rate of methicillin sensitive S. aureus (MSSA) for erythromycin was up to 76.8 ％,and for tetracycline,gentamycin,ciprofloxacin,and ofloxacin,were less than 25.0 ％. In 10 years,the average resistance rates of MRSA and MSSA for 11 kinds of common antibiotics had no obvious change. Conclusion The constituent rate of MRSA was high in The First Hospital of China Medical University,especially from the areas that were not sterile,suggesting that clinicians should pay attention to the identification of infection and sources for MRSA,which were from such areas. Hospital infection control should be focused on at the same time,in order to reduce the incidence of MRSA.

Queratolisis punctata / Pitted keratolysis

Se presenta caso de paciente de 13 años, de sexo femenino, con historia de 2 meses de evolución de lesiones aspecto crateriforme en planta de pie izquierdo, acompañado de bromhidrosis, dolor y ardor e impotencia funcional. El cultivo reveló la presencia de Staphylococcus aureus meticilino sensible. Las lesiones mejoraron con tratamiento antibiótico tópico con mupirocina y queratolíticos, quedando como diagnóstico una queratólisis punctata.

A 13-year-old female patient case is presented with a 2 months history of lesions on the left foot, accompanied by bromhydrosis, pain, burning, and functional impotence. Tissue culture revealed the presence of sensitive methicillin Staphylococcus aureus. The lesions improved with topical antibiotic treatment with mupirocin and keratolytics, final diagnosis was punctate keratolysis.

Comparison in prognosis of hospital-acquired pneumonia due to methicillin-resistant and methicillin-sensitive Staphylococcus aureus：analysis of propensity score matching / 中国感染控制杂志

Objective To study whether methicillin-resistant Staphylococcus aureus (MRSA)will increase the burden of patients with hospital-acquired pneumonia (HAP).Methods Patients with Staphylococcus aureus HAP in a hospital between January 1 ,2013 and November 31 ,2014 were selected,patients with MRSA HAP were as case group,patients with methicillin-sensitive Staphylococcus aureus (MSSA)HAP were as control group,propen-sity score matching (PSM)analysis were conducted to compare the prognosis of MRSA HAP and MSSA HAP (length of hospital stay, duration from infection to discharge, mortality, total therapeutic cost ). Results APACHE II score in case group was higher than control group before PSM was conducted,length of hos-pital stay and duration from infection to discharge were both longer than control group (40[20,94]d vs 28[21 ,53] d;19[10,46]d vs 17[8,29]d,respectively,both P 0.05 ),data were balanced and comparable;there were no significant difference in length of hospital stay between two groups (28[21 ,52]d vs 28[21 ,53]d),duration from in-fection to discharge (15[9,25]d vs17[8,29]d),mortality(10.87% vs 15.22%),and total therapeutic cost (121 013.5[80 747.21 ,176 200]yuan vs 119 911 .2[66 994.08,241 184.7]yuan)(all P >0.05).Conclusion APACHE II score is an important factor affecting prognosis;after balancing this factor,there is no difference in the prognosis of patients with MRSA and MSSA HAP,MRSA HAP can not increase the burden of disease.

Correlación entre la detección de superantígenos y resistencia a oxacilina en aislamientos hospitalarios de Staphylococcus aureus / Correlation between detection of superantigens and oxacillin resistance of Staphylococcus aureus in hospital isolates

Objetivo: Establecer la correlacion entre la deteccion de superantigenos (MSSA) y la susceptibilidad a oxacilina de Staphylococcus aureus (MRSA) en aislamientos hospitalarios. Materiales y métodos: En 81 aislamientos de Staphylococcus aureus de origen hospitalario, la susceptibilidad a oxacilina se establecio por un sistema automatizado y la deteccion de 22 genes de superantigenos fue realizada mediante PCR individual y multiple. Resultados: La MRSA fue del 38,3%. Todos los aislamientos MRSA portaban uno o mas genes de superantigenos; y el 92% de MSSA. El numero de genotipos fue variable, pero un hallazgo relevante fue que el cluster egc solo fue detectado en MRSA (48,4%). Los genes no clasicos mas detectados en MRSA fueron sem (53,1%) y seg (28,4%); y sem (37%) y seq (30,9%) para MSSA. El gen sec clasico (13,6%) fue mas prevalente en MSSA, y en MRSA, los clasicos fueron de muy baja frecuencia. Para todos los genes, los genes seg , sej , sen , seo y seq mostraron diferencias estadisticamente significativas entre los aislamientos MRSA y MSSA. Conclusión: Este estudio no permitio sacar conclusiones concluyentes para establecer la relacion entre la deteccion de superantigenos y la susceptibilidad a oxacilina (MRSA vs. MSSA). Aunque, el numero de genotipos fue variable, la presencia del cluster egc solamente en aislamientos MRSA es un hallazgo interesante, y en posteriores estudios se podria determinar la importancia del cluster egc.

Objective: To establish the relationship between the detection of superantigens (MSSA) and Staphylococcus aureus resistance to oxacillin in hospital isolates. Material and methods: In 81 isolates of Staphylococcus aureus of hospital origin, an oxacillin susceptibility test was performed by an automated system and 22 superantigenic genes were obtained using single and multiplex PCR. Results: The MRSA was 38.3%. All MRSA isolates carried one or more genes for superantigens and 92.0% of MSSA. The numbers of genotypes for the 2 groups were variable, but the most important finding was that the egc cluster was detected only in MRSA (48.4%). The non-classic genes more often detected in MRSA were sem (53.1%) and seg (28.4%); in MSSA they were sem (37.0%) and seq (30.9%). The gen classic sec (13.6%) was more prevalent in MSSA and in MRSA; the classic genes were very low in frequency. For all genes, the genes: seg , sej , sen , seo and seq showed statistically significant differences between MRSA and MSSA isolates. Conclusion: This study did not reveal a clear relationship between the detection of superantigens and oxacillin susceptibility (MRSA vs. MSSA). Although the number of genotypes varied, the presence of egc cluster only in the MRSA isolate was an important finding. Further studies are needed to establish the importance of the egc cluster.

A retrospective study of the prevalence and sensitivity pattern of Methicillin-resistant Staphylococcus aureus in a Chong Hua Hospital, Cebu City, 2007-2010

Background/Objective@#There is a deep concern about the rapid rise in resistance of bacteria to antimicrobial agents. Methicillin-resistant Staphylococcus aureus (MRSA) which pose challenges to the medical community. This study aimed to determine the prevalence and sensitivity pattern of Methicillin-Resistant Staphylococcus Aureus (MRSA) in a tertiary hospital in Cebu City from January 1, 2007 to December 31, 2010. @*Methods@#Charts of patients with MRSA growths were reviewed upon their admission. The sensitivity pattern, demographic profile and risk factors were noted. @*Results@#Out of the 637 isolates of Staphylococcus aureus, MRSA had a prevalence rate of 38.6% (n=246), while Methicillin Sensitive Staphylococcus aureus (MSSA) had 61.4% (n=391). The prevalence rate of health-care associated MRSA was 2% (n=5). The majority of the specimens sent for culture were wound/abscess (70% of pediatric and 76% of adult patients isolates). All MRSA growths were resistant to penicillin G, ampicillin, oxacillin, cefuroxime and amikacin. Local MRSA strains were still susceptible to ciprofloxacin (82.3%), clindamycin (90.6%), erythromycin (91.5%), and sulfamethoxazole-trimethoprim (85.9%). There was no resistance to linezolid and vancomycin. Vancomycin-resistant Staphylococcus aureus was not isolated. The mortality rate on both pediatric and adult population was 2.1% and 4.8%, respectively. @*Conclusion@#The prevalence of MRSA is increasing. Clindamycin, erythromycin, sulfamethoxazole- trimethoprim and vancomycin are excellent treatment options treat MRSA.

To study the correlation between carrier status of nasal Staphylococcus aureus in patients on haemodialysis with hepatitis C, hepatitis B and their sociodemographic features / Estudiar la correlación entre el portador del Estafilococo dorado nasal en pacientes de hemodiálisis con hepatitis C, hepatitis B y sus características sociodemográficas

AIM: To study the correlation of nasal Staphylococcus aureus carrier status in patients on haemodialysis, infected by hepatitis C virus (HCV), hepatitis B virus (HBV), and their sociodemographic features. SUBJECTS AND METHODS: A survey, including patients ' sociodemographic features, was applied to patients by physicians in face to face interviews. Medical records regarding their serologic data were recorded from haemodialysis centres. Nasal swab samples of 2 cm depth from both nostrils of patients were obtained for nasal culture. Samples were inoculated in 5% sheep blood agar and incubated in an incubator at a temperature of 37ºCfor 24 hours. The results were studied by the same microbiologist. RESULTS: A total of 185 patients were enrolled in the study. According to culture results, 14.1% of patients (n = 26) had methicillin sensitive Staphylococcus aureus (MSSA) and 1.1% (n = 2) had methicillin resistant Staphylococcus aureus (MRSA). Status of viral hepatitis was 3.8% (n = 8), 10.8% (n = 20) for HBV and HCV, respectively. Forty per cent (n = 8) of patients with HBV (+) had MSSA carrier status. Statistically significant positive correlation between MSSA and HCV carrier was detected (r = 0.325, p = 0.001) but not between HBV carrier and MSSA (p = 0.255). CONCLUSION: In the present study, significant positivity was detected between MSSA carrier status and HCV in patients on haemodialysis and who have lived together with < 2 family members at home. Particularly, statistically significant correlation between HCV (+) and MSSA carrier was observed.

OBJETIVO: Estudiar la correlación entre el portador del Estafilococo dorado (Staphylococcus aureus) nasal en pacientes de hemodiálisis infectados por el virus de la hepatitis C (VHC), el virus de la hepatitis B (VHB), y sus características sociodemográficas. SUJETOS Y MÉTODOS: Una encuesta que incluía características sociodemográficas de los pacientes fue aplicada a pacientes por médicos en entrevistas cara a cara. Historias clínicas contentivas de sus datos serológicos, fueron registradas a partir de los centros de hemodiálisis. Muestras defrotis nasales de 2 cm de profundidad de ambas fosas nasales, fueron obtenidas para un cultivo nasal. Se inocularon muestras en agar de sangre de oveja al 5%, e incubadas en una incubadora a una temperatura de 37ºC por 24 horas. Los resultados fueron examinados por el mismo microbiólogo. RESULTADOS: Un total de 185 pacientes fueron enrolados en el estudio. Según los resultados del cultivo, 14.1% pacientes (n = 26) tenían estafilococo dorado sensible a la meticilina (MSSA) y 1.1% (n = 2) tenían estafilococo dorado resistente a la meticilina (MRSA). El estatus de las hepatitis virales fue 3.8% (n = 8), y 10.8% (n = 20) para HVB y HVC respectivamente. Cuarentapor ciento (n = 8) de los pacientes con HVB (+) eran portadores del MSSA. Estadísticamente, se detectó una correlación positiva significativa (r = 0.325, p = 0.001), entre MSSA y el portador de VHC, no así entre el portador del VHByMSSA (p = 0.255). CONCLUSIÓN: En el estudio presente, se detectó una positividad significativa entre el estatus de; portador de MSSA y los pacientes de VHC en hemodiálisis, que vivían junto con [= dos o menos de dos] miembros de la familia en casa. En particular, se observó una correlación estadísticamente significativa entre HCV (+) y el portador MSSA.

Prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) Nasal carrier in Health Care Workers.

Methicillin resistance Staphylococcus aureus (MRSA) is an important nosocomial pathogen that causes severe morbidity and mortality worldwide. In recent years, nosocomial outbreaks of methicillin resistance Staphylococcus aureus (MRSA) has become a major infection control problem. Colonized employees are generally asymptomatic; they are a potential reservoir and disseminator of MRSA in hospitals. Nasal screening of health care workers (HCW) for MRSA is performed routinely in several countries, typically when more than one MRSA – colonized patient is identified in high risk ward, such as intensive care unit (ICU). This study was performed at PSG Hospitals to assess the prevalence of MRSA nasal colonization in health care workers and their sensitivity pattern. The prevalence of MRSA carriage among HCW’s was quite low (3.3%) in our institution. It has been recommended that, in case of epidemic in the hospital, all health care workers should be examined for MRSA colonization.