Stenotrophomonas maltophilia pseudo-outbreak at a University Hospital Bronchoscopy unit in Turkey / Pseudo-brote de Stenotrophomonas maltophilia en una unidad de Broncoscopia del Hospital Universitario en Turquía

OBJECTIVE: Stenotrophomonas maltophilia is an opportunistic pathogen found predominantly in the enviroment and hospital setting. Invasive procedures and treatment methods, instruments used for diagnosis and irrational antibiotic use play major roles in the spread of this pathogen. The study aimed to evaluate consecutive S maltophilia isolation from bronchoalveolar lavage samples during bronchoscopy procedure during a week. METHODS: Four patients consecutively had S maltophilia isolated during bronchoscopy between September 8 and 15, 2012. The identification of the isolates and their antibiotic susceptibility were studied by automated Vitek version 2.0 (Biomerieux, France) system. The clonal relationship between the isolates was studied by enterobacterial repetitive intergenic consensus (ERIC) polymerase chain reaction (PCR). RESULTS: Four consecutive S maltophilia isolates had identical band patterns and showed clonal relatedness. CONCLUSION: Bronchoscopy is a common invasive procedure that is utilized in chest diseases departments and intensive care units (ICUs). Contamination may take place due to inappropiate use and cause spread of infectious pathogens. In the current study, we detected consecutive S maltophilia strains with identical band patterns isolated within a week. After appropiate disinfection and cleaning procedures, no further isolation was detected.

OBJETIVO: Stenotrophomonas maltophilia es un patógeno oportunista que se encuentra predominantemente en el medio ambiente y entorno de los hospitales. Los procedimientos invasivos y los métodos de tratamiento, los instrumentos utilizados para el diagnóstico y tratamiento, así como el uso irracional de antibióticos, desempeñan un importante papel en la propagación de este patógeno. Este estudio persigue evaluar el aislamiento consecutivo de S maltophilia de las muestras de lavado broncoalveolar durante el procedimiento broncoscópico en el período de una semana. MÉTODOS: A cuatro pacientes se les aisló S maltophilia consecutivamente en broncoscopias realizadas entre el 8 y el 15 de septiembre de 2012. La identificación de los aislamientos y su sensibilidad a los antibióticos fueron estudiados por el sistema automatizado Vitek 2 (Biomerieux, Francia). La relación clonal entre los aislamientos fue estudiada mediante consenso intergénico repetitivo enterobacteriano (ERIC) en conjunción con la reacción en cadena de la polimerasa (PCR). RESULTADOS: Cuatro aislados consecutivos de S maltophilia tenían patrones de banda idénticos y exhibían conexidad clonal. CONCLUSIÓN: La broncoscopia es un procedimiento invasivo común que se aplica en los departamentos de enfermedades torácicas, y las unidades de cuidados intensivos (UCI). La contaminación puede ocurrir debido a usos inapropiados y a la propagación de agentes patógenos infecciosos. En el presente estudio, hemos detectado cepas de S maltophilia consecutivas con idénticos patrones de banda aislados en una semana. Después de los procedimientos de limpieza y desinfección adecuada, no se detectó ningún otro aislamiento.

Pseudo-outbreak of Brevundimonas diminuta / 대한임상미생물학회지

Brevundimonas diminuta is a lactose non-fermenting Gram-negative rod associated with infection in immunocompromised patients. In three patients from two general wards, B. diminuta was isolated in blood culture sample. The clinical features of the patients did not coincide with the blood culture result, and pseudo-outbreak was suspected. These isolated were biochemically identified as Brevundimonas diminuta, and 16S rRNA sequencing confirmed their identification. The PFGE result showed a single pattern, and their clonality was assumed.

Pseudo-outbreak of Clostridium difficile associated diarrhea (CDAD) in a tertiary-care hospital / Pseudo-surto de diarréia associada a Clostridium difficile (DACD) em hospital terciário

The objective of this study was to describe a pseudo-outbreak of C. difficile in a hospital, following a change in the method used to detect the toxin. In February 2002, there were two cases of CDAD and in March 7 occurred, coinciding with a change of the test (from detection of toxin A to toxin A/B). An outbreak was suspected. Active surveillance and education of staff were started. A CDAD case was defined as a patient with acute onset of diarrhea (³ three episodes of liquid stools) and a positive stool test. They were classified as hospital or community-acquired. Stool samples were also collected for C. difficile culture and isolates were typed using AP-PCR. From March 2002 through December 2003 there were 138 cases of CDAD: 70 percent were hospital-acquired and among the 30 percent with CDAD present on admission, most (81 percent) came directly from the community (50 percent had no history of hospitalization). Fifty-two percent of hospital-acquired CDAD and 94 percent of cases on admission had already used antibiotics. The incidence of CDAD in hospitalized patients during surveillance was 3.3 per 1000 patient-admissions. The incidence of CDAD present on admission was 6.1/1000 patients. Sixteen isolates were typed and presented 13 different profiles. In conclusion, the CDAD increase in our study occurred due to change in diagnostic methods and not due to an outbreak, as suspected initially. The incidence in hospitalized patients was much lower than in reported outbreaks. There were 13 molecular types suggesting that an outbreak did not occur. CDAD was largely community-acquired.

O objetivo deste estudo foi descrever um pseudo-surto de C. difficile em um hospital após a troca do método de detecção de toxina. Em fevereiro de 2002 houve dois casos de DACD e em março ocorreram sete casos, que coincidiram com a mudança de teste (que detectava apenas toxina A e passou a detectar toxinas A e B). Foi suspeitado que houvesse um surto e vigilância ativa e reforço educacional para os profissionais de saúde foi implantado. Um caso de DACD foi definido como um paciente com início abrupto de diarréia (> 3 episódios de fezes líquidas) e um teste positivo. Os casos foram classificados como de aquisição comunitária ou hospitalar. Foram colhidas fezes para cultura para C. difficile e os isolados foram tipados por AP-PCR. De março de 2002 a dezembro de 2003 houve 138 casos de DACD: 70 por cento foram hospitalares e, entre os 30 por cento de casos comunitários, a maioria (81 por cento) foi de pacientes provenientes diretamente da comunidade (50 por cento não tinham histórico de internação). Cinquenta e dois por cento dos casos de DCAD hospitalar e 94 por cento de casos na admissão haviam utilizado antimicrobianos. A incidência de DCAD em pacientes internados foi de 3,3/100 pacientes e na admissão foi 6,1/1000 pacientes. Dezesseis isolados foram tipados e apresentaram 13 perfis diferentes. Em conclusão, o aumento de DACD no nosso estudo ocorreu por uma mudança de método diagnóstico e não devido a um surto como foi suspeitado inicialmente. A incidência em pacientes internados foi muito inferior ao que já foi relatado em surtos. Houve 13 perfis moleculares sugerindo que não ocorreu um surto. DACD foi, em grande parte, de aquisição comunitária.

Recognition of a Pseudo-Outbreak of Cladosporium Species by Continuous Monitoring of Culture Results / 병원감염관리

BACKGROUND: Cladosporium spp. are dematiaceous fungi that are commonly isolated from indoor and outdoor environments, including hospital air. This fungus is rarely pathogenic to humans, but has been reported to cause infections of the skin and toenails, as well as sinusitis and pulmonary infections. The monitoring of culture results was conducted to identify the outbreak of an unknown black fungal infection between January and March 2006 in a University hospital, and infection control activity was performed to identify the cause of the outbreak. METHODS: An epidemiological investigation of 22 patients with infections caused by an unknown black fungus was conducted. Microscopic examination and molecular analysis on the internal transcript spacer (ITS) region was performed to identify the black fungus. To detect the source of contamination, a culture of environmental specimens was performed, and then, disinfection of the laboratory was implemented. RESULTS: The patients with black fungi belonged to various departments and wards. No symptoms of fungal infection were recognized on the basis of the survey. The black fungus was identified as Cladosporium spp. on the basis of morphological features and ITS region sequencing. Culturing of environmental specimens was performed in the laboratory. Black fungi were isolated from a specimen from a rack and had the same morphological features with Cladosporium spp. from clinical specimens. After the rack was autoclaved, Cladosporium spp. from clinical specimens was no longer isolated. CONCLUSION: Epidemiological investigation, microscopic examination, and molecular analysis revealed that the sudden increase in the isolation rate of Cladosporium spp. from clinical specimens was the result of a pseudo-outbreak caused by the contamination of a rack. To our knowledge, this is the first report of a pseudo-outbreak of Cladosporium spp. Continuous monitoring of culture results is important to avoid unnecessary labor for nosocomial infection control.

Pseudooutbreak of Acinetobacter spp. Bacteriuria Confirmed by 16S rRNA Gene Sequence Analysis / 감염과화학요법

BACKGROUND: Acinetobacter spp. is increasingly implicated in hospital-acquired infections. We experienced a pseudooutbreak of Bordetella bronchiseptica bacteriuria identified with biochemical tests, that was later identified as Acinetobacter spp. by using 16S rRNA gene sequence analysis. MATERIALS AND METHODS: Five in-ward patients were found to have B. bronchiseptica bacteriuria without symptoms of urinary tract infection between September 23 and 26 of 2005. We conducted pulsed field gel electrophoresis (PFGE) of the bacteria and epidemiological investigation of this pseudooutbreak. In addition, 16S rRNA gene sequence analysis was performed for the verification of the strains. RESULTS: All 5 isolates were identified as B. bronchiseptica with similar antibiogram by VITEK system. There was no evidence of any symptom or sign of urinary tract infection. The source of this pseudooutbreak was not detected even after performing environmental culture and interviews with healthcare workers. We could not get the appropriate results from the first PFGE with XbaI restriction enzyme. B. bronchiseptica is an unusual organism in human so we conducted 16S rRNA gene sequence analysis for verification. The analysis of 16S rRNA gene sequence with 5 isolates demonstrated 99-100% similarity to a sequence of Acinetobacter spp. (AU1523). According to the results of 16S rRNA gene sequence analysis, we performed the second PFGE with SmaI restriction enzyme, which showed indistinguishable pattern among the all 5 isolates. CONCLUSION: This investigation suggests that the combined method of 16s rRNA gene sequence analysis and PFGE would be helpful for investigation of outbreak caused by unusual organisms

Pseudooutbreak of Acinetobacter spp. Bacteriuria Confirmed by 16S rRNA Gene Sequence Analysis / 감염과화학요법

BACKGROUND: Acinetobacter spp. is increasingly implicated in hospital-acquired infections. We experienced a pseudooutbreak of Bordetella bronchiseptica bacteriuria identified with biochemical tests, that was later identified as Acinetobacter spp. by using 16S rRNA gene sequence analysis. MATERIALS AND METHODS: Five in-ward patients were found to have B. bronchiseptica bacteriuria without symptoms of urinary tract infection between September 23 and 26 of 2005. We conducted pulsed field gel electrophoresis (PFGE) of the bacteria and epidemiological investigation of this pseudooutbreak. In addition, 16S rRNA gene sequence analysis was performed for the verification of the strains. RESULTS: All 5 isolates were identified as B. bronchiseptica with similar antibiogram by VITEK system. There was no evidence of any symptom or sign of urinary tract infection. The source of this pseudooutbreak was not detected even after performing environmental culture and interviews with healthcare workers. We could not get the appropriate results from the first PFGE with XbaI restriction enzyme. B. bronchiseptica is an unusual organism in human so we conducted 16S rRNA gene sequence analysis for verification. The analysis of 16S rRNA gene sequence with 5 isolates demonstrated 99-100% similarity to a sequence of Acinetobacter spp. (AU1523). According to the results of 16S rRNA gene sequence analysis, we performed the second PFGE with SmaI restriction enzyme, which showed indistinguishable pattern among the all 5 isolates. CONCLUSION: This investigation suggests that the combined method of 16s rRNA gene sequence analysis and PFGE would be helpful for investigation of outbreak caused by unusual organisms

Pseudo-outbreak of Stenotrophomonas maltophilia Due to Contamination of Bronchoscope / 대한진단검사의학회지

BACKGROUND: We noticed an abrupt increase in the isolation of Stenotrophomonas maltophilia from bronchoalveolar lavage (BAL) specimens collected at Chosun University Hospital. We performed surveillance cultures in order to identify the source of what appeared to be a pseudo-outbreak. METHODS: To investigate a possible nosocomial outbreak of S. maltophilia, we performed culture of 11 environmental specimens obtained from a bronchoscopy room and two bronchoscopes. Pulsedfield gel electrophoresis (PFGE) was used to examine the genetic relatedness among the strains of S. maltophilia recovered from BAL specimens of 3 patients and 1 environmental sample, as well as 9 unrelated strains of S. maltophilia as a control. RESULTS: During a 7 day-period in March 2006, S. maltophilia was isolated from the BAL specimens of 7 of 13 (54%) patients, compared to only 5 of 188 (2.6%) patients during the 6-month period prior to that period. S. maltophilia was isolated from 1 of the 11 environmental samples, which was obtained from a fiberoptic bronchoscope suction channel. All 7 patient isolates and one environmental isolate exhibited similar antibiotic susceptibility patterns. PFGE analysis of the genomic DNA from epidemic strains demonstrated an identical banding pattern, whereas each of epidemiologically unrelated strains showed a unique electrophoretic pattern. CONCLUSIONS: Apparently one of the hospital bronchoscopes became contaminated with S. maltophilia during a bronchoscopic procedure. It is likely that subsequent specimen contamination occurred because the bronchoscope had been inadequately cleaned and disinfected. The pseudo-outbreak was controlled successfully by removing the source of infection.

Pseudo-Outbreak of Bloodstream Infections by Serratia mercescens / 병원감염관리

BACKGROUND: Serratia marcescens proliferates well in a humid environment or soil and is recently considered as an important pathogen for the severe nosocomial infections. this organism is spreads easily by hand-to-hand transmission, and contaminates medical equipment used for invasive procedures, working environment, medications, and soap. METHODS: We investigated the source of an outbreak of bloodstream infections by S. marcescens isolated that occurred during the period from July to December, 2004, at a university hospital in Gyeonggi Province and attempted to intervene in the outbreak and control it. RESULTS: From July to December, 2004, S. marcescens grew from 296 blood culture from 283 patients. The medical charts of the patients were reviewed, and surveillance cultures were taken to identify the outbreak of nosocomial infections and risk factors. Only four cases of infection were identified and all remaining positive blood cultures were due to contamination. Nine isolates randomly selected from the 296 S. marcescens showed an identical pulsed-field gel electrophoresis pattern. To identify the source of infection, environmental culture and hand cultures of the related medical workers were carried out, but S. marcescens was not isolated. CONCLUSION: As the result of aggressive infection control activities, such as re-education on environmental management methods, hand washing techniques, and blood culture sampling techniques, no more S. marcescens had been grown in blood culture since January, 2005.