Bacteriological Profile of Wound Swab and Pus Samples Using Conventional Media and Chromogenic Medium.

Background: Wound infections continue to be a causeof concern as they can delay healing and cause woundbreakdown. Their effective treatment demands quickisolation and identification of causative organisms withappropriate antibiotic sensitivity pattern. Material andMethods: Wound swab and pus samples received frominpatient as well as outpatient department of all agegroups and both genders were processed usingconventional media as well as chromogenic medium(HiCrome UTI) and results of both were compared.Antibiotic sensitivity testing was done on Vitek 2Compact automated system. Results: Among 342samples, 77% showed growth. Fifty eight percentagewere Gram negative and 42% were Gram positiveorganisms. Polymicrobial growth was seen in 11% ofsamples. HiCrome UTI isolated all organisms inculture. Colony characteristics and colour of all isolateson HiCrome UTI were comparable to theiridentification on Vitek 2 Compact. Among the Grampositive organisms, commonest was MethicillinSensitive Staphylococcus aureus (MSSA 42%)followed by Methicillin Resistant Staphylococcusaureus (MRSA 33%), Enterococcus faecalis (10%),Staphylococcus epidermidis (8%), Staphylococcushaemolyticus (3%), Streptococcus pyogenes (2%) andStreptococcus agalactiae (2%). Most of the Grampositive organisms were sensitive to vancomycin,teicoplanin, linezolid and clindamycin The commonGram negative organisms were E. coli (36%),Klebsiella pneumoniae (20%), Pseudomonasaeruginosa (18%), Proteus mirabilis (7%),Enterobacter cloacae (6%) and Acinetobacterbaumannii (4%). Most of the Gram negative organismswere sensitive to cefepime, beta lactams-betalactamase inhibitors, aminoglycosides and fluoroquinolones. Conclusion: Gram-negative organismspredominated in our study. HiCrome UTI agar can beused as a cost-effective approach for rapid isolation ofall organisms. It gives definite identification ofcommon organisms and thus reduces turn-around-timefor the same. It provides presumptive identification ofinfrequent organisms which can be further confirmedby simple biochemical tests. Hence these properties ofHiCrome UTI agar help serve the purpose especiallyfrom mixed cultures and in resource constraint settings

Incidencia de Escherichia coli O157: H7 en heces de rumiantes lactantes con síndrome diarreico / Incidence of Escherichia coli 0157: H7 in feces of lactating ruminants with diarrheal syndrome

RESUMEN Objetivo. Identificar Escherichia coli O157:H7 presente en heces diarreicas de rumiantes lactantes con síndrome diarreico y seguridad de ingesta de calostro. Materiales y métodos. Se realizó un muestreo de 316 rumiantes durante el período de agosto 2015 a marzo 2016 en los municipios de Río Grande, General Enrique Estrada, Morelos y Calera de Víctor Rosales del estado de Zacatecas, 67 de bovinos, 183 de ovinos y 66 de caprinos. Resultados. Se identificaron en medio cromogénico CHROMagarTM: 260 coliformes, 78 Escherichia coli O157:H7, 16 Proteus spp., y 25 colonias de bacterias sin identificar con este medio, encontrándose una incidencia de Escherichia coli O157:H7 de 22.03% en los cuatro municipios. Conclusiones. Escherichia coli O157:H7 es la segunda bacteria encontrada en heces de rumiantes con un 22% de incidencia, la cual es un factor de riesgo de muerte en rumiantes lactantes (menos de 21 días de nacidos) causando pérdidas económicas y riesgo para la salud de la población del estado de Zacatecas.

ABSTRACT Objective. To identify Escherichia coli 0157:H7 present in diarrheal feces of lactating ruminants with diarrheal syndrome and safety of colostrum intake. Materials and methods. A feces sampling of 316 ruminants was carried out during the period of August 2015 to March 2016 in the municipalities of Río Grande, General Enrique Estrada, Morelos and Calera de Victor Rosales of the state of Zacatecas, obtained from 67 cattle, 183 sheep and 66 goats. Results. The following were identified in CHROMagarTM chromogenic medium: 260 coliforms, 78 Escherichia coli 0157:H7, 16 Proteus spp. and 25 colonies of unidentified bacteria, finding an incidence of Escherichia coli 0157:H7 of 22.03% in the four municipalities. Conclusions. Escherichia coli 0157:H7 is the second bacteria found in ruminant feces with an incidence of 22%, which is a mortality risk factor in lactating ruminants (less than 21 days old), causing economic loss and health risk for the population of the state of Zacatecas.

Evaluation of a new chromogenic media for the isolation and culture of Clostridium difficile / 临床检验杂志

Objective@#To evaluate the performance of a chromogenic agar developed by our laboratory for the isolation and culture of Clostridium difficile (CDCA). @*Methods@#The chromogenic specificity of CDCA was evaluated by inoculation of C. difficile and other standard strains, and the sensitivities of CDSA (BD), CDIF (BioMérieux) and CDCA were determined by the C. difficile standard strains respectively. A total of 120 clinical stool specimens were cultured for C. difficile by three chromogenic media respectively. The colonies were further identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and tpi gene was also detected. The sample which could be identified as C. difficile in any of the three chromogenic medium was defined as true positive. @*Results@#Most of standard strains were inhibited by CDCA, however some Clostridium species including C. clostridiiforme, C. bifermentans, C. tertium and Bacteroides fragilis grew lightly with chromogenic reaction. The sensitivities of CDSA, CDIF and CDCA were 2.0×105 CFU/mL, 8.0×101 CFU/mL and 4.0×10 2 CFU/mL, respectively. Among the 120 samples, 31 (25.8%) were defined as true C. difficile positive samples, while the positive rate of CDSA, CDIF and CDCA were 25 (20.8%), 28 (23.3%) and 26 (21.7%), respectively. There was no significant difference for clinical diarrhea specimens among the three chromogenic media (χ 2 =0.418, P=0.811). In comparison to the standard, the sensitivity, specificity, positive predictive value and negative predictive value were 83.8%, 100%, 100% and 94.7% for CDCA; 90.3%, 98.9%, 96.6% and 96.7% for CDIF; and 80.6%, 100%, 100% and 93.7% for CDSA. @*Conclusion@#The CDCA developed by our laboratory could be used to preliminarily isolate C. difficile with good specificity and sensitivity.

Comparison between four usual methods of identification of candida species / Comparação entre quatro métodos usuais de identificação de espécies de Candida

SUMMARYInfection by Candidaspp. is associated with high mortality rates, especially when treatment is not appropriate and/or not immediate. Therefore, it is necessary to correctly identify the genus and species of Candida. The aim of this study was to compare the identification of 89 samples of Candidaspp. by the manual methods germ tube test, auxanogram and chromogenic medium in relation to the ID 32C automated method. The concordances between the methods in ascending order, measured by the Kappa index were: ID 32C with CHROMagar Candida(κ = 0.38), ID 32C with auxanogram (κ = 0.59) and ID 32C with germ tube (κ = 0.9). One of the species identified in this study was C. tropicalis,which demonstrated a sensitivity of 46.2%, a specificity of 95.2%, PPV of 80%, NPV of 81.1%, and an accuracy of 80.9% in tests performed with CHROMagar Candida;and a sensitivity of 76.9%, a specificity of 96.8%, PPV of 90.9%, NPV of 91%, and an accuracy of 91% in the auxanogram tests. Therefore, it is necessary to know the advantages and limitations of methods to choose the best combination between them for a fast and correct identification of Candidaspecies.

RESUMOA infecção por Candidaspp. está associada com alta mortalidade, principalmente quando o tratamento não é adequado, nem imediato. Assim, a correta identificação do gênero e espécie é necessária. O objetivo deste trabalho foi comparar 89 amostras de Candidaspp. pelos métodos manuais prova do tubo germinativo, auxanograma e CHROMagar em relação ao método automatizado ID 32C. As concordâncias entre os métodos em ordem crescente, medidas pelo coeficiente de Kappa, foram: ID 32C com CHROMagar Candida(κ = 0,38), ID 32C com auxanograma (κ = 0,59) e ID 32C com tubo germinativo (κ = 0,9). Uma das espécies identificadas neste trabalho foi a C. tropicalis, que demonstrou uma sensibilidade de 46,2%, especificidade de 95,2%, VPP de 80%, VPN de 81,1% e acurácia de 80,9% nos testes com CHROMagar Candidae uma sensibilidade de 76,9%, especificidade de 96,8%, VPP de 90,9%, VPN de 91% e acurácia de 91% nos testes de auxanograma. Portanto, o conhecimento das vantagens e limitações dos métodos é necessário para a escolha da melhor combinação entre os mesmos visando uma rápida e correta identificação das espécies de Candida.

Selectivity evaluation of a new chromogenic medium to detect group B Streptococcus.

Background: Group B Streptococcus (GBS) is an important pathogen that causes serious infections in newborns. Pregnant screening and intrapartum antibiotic prophylaxis are actually the strategies to prevent GBS disease in neonates because vaccination is under investigation. Materials and Methods: Simultaneously, 156 isolates of GBS and 156 isolates other than GBS covering 17 different species, were tested to evaluate the selectivity of a new chromogenic medium to screen GBS. Results: The new new chromogenic medium showed an excellent performance, exhibiting a very high level of inclusivity (100%) and exclusivity (96.1%).

Evaluación del medio cromogénico CromoCen® ENT para el diagnóstico clínico de Enterococcus / Assessment of the CromoCen ENT® chromogenic medium for clinical diagnosis of Enterococcus species

Introducción: la frecuente incidencia de Enterococcus en los hospitales y su creciente resistencia antimicrobiana a nivel mundial, ha incrementado la necesidad de su vigilancia y control intrahospitalario, por lo que resulta imprescindible contar con medios diagnósticos más sensibles y exactos. Objetivo: ampliar la evaluación de la funcionalidad del medio cromogénico CromoCen® ENT para el aislamiento e identificación de Enterococcus spp. procedentes de muestras clínicas. Métodos: se analizaron 150 muestras clínicas (orina, sangre, fecales, exudados vaginales, exudados de lesiones de piel y de catéteres) desde enero hasta abril de 2010, empleando el medio cromogénico y los medios convencionales correspondientes como controles, se evaluó la incidencia de Enterococcus spp. Se identificaron los aislamientos con un conjunto de 12 pruebas bioquímicas. A partir de los datos de la identificación bioquímica se determinaron los indicadores de calidad tanto para el medio CromoCen® ENT como para los medios de referencia. Resultados: el medio cromogénico promovió el crecimiento de Enterococcus spp. en solo 24 h, lo cual permitió su fácil reconocimiento por la coloración rosada de las colonias. Los indicadores de calidad diagnóstico mostraron valores superiores a 95 %. El mayor porcentaje de aislamientos se obtuvo en las muestras de orina. Enterococcus faecalis resultó la especie mayormente encontrada en el total de las muestras. Conclusiones: CromoCen® ENT permitió la correcta y rápida identificación de Enterococcus spp. procedentes de diversas muestras clínicas.

Introduction: the frequent incidence of Enterococci at hospitals and their growing antimicrobial resistance worldwide make the in-hospital surveillance and control a pressing need; consequently, it is indispensable to avail of more sensitive and accurate diagnostic means. Objective: to broaden the evaluation of functionality of CromoCen® ENT chromogenic medium for the isolation and identification of Enterococcus spp. from clinical samples. Methods: one hundred and fifty clinical samples were analyzed (urine, blood, feces, vaginal smears, skin lesion exudates and exudates from catheters) in the January-April period, 2010 by using the chromogenic medium and the corresponding conventional culture media as controls; the incidence of Enterococcus spp was evaluated. The isolations were identified with 12 biochemical tests. From the biochemical identification data, it was possible to determine the quality indicators for both CromoCen® ENT and the reference media. Results: the chromogenic medium encouraged the growth of Enterococcus species in 24 hours, allowing their easy recognition due to the pink coloration of the colonies. The diagnostic quality indicator values were over 95 %. The highest percentage of isolates was observed in the urine samples. Enterococcus faecalis was the mostly found species. Conclusions: CromoCen® ENT allowed quick and accurate identification of Enterococcus spp. from various clinical samples.

Direct Detection of Methicillin-Resistant Staphylococcus aureus from Blood Cultures Using Three Non-Molecular Methods: PBP2a Latex Agglutination, PBP2a Rapid Immunochromatographic Assay and MRSA-Chromogenic Medium / 대한임상미생물학회지

BACKGROUND: This study compared three non-molecular methods for the detection of methicillin-resistance directly from blood cultures containing Staphylococcus aureus: penicillin-binding protein (PBP) 2a latex agglutination (LA), PBP2a immunochromatographic assay (ICA) and MRSA chromogenic medium (CM). METHODS: Fifty methicillin-resistant S. aureus (MRSA) and 50 methicillin-susceptible S. aureus (MSSA) were seeded into blood-culture bottles. When isolates returned a positive signal, 5 mL of culture was added to serum separator tubes and centrifuged at 1,300 g for 10 min. The pellets were then used as the inoculum for the PBP2a LA, MRSA-CM and PBP2a ICA. The pure colony was used for PBP2a LA test, additionally. RESULTS: The respective sensitivities and specificities were 98 and 100% for PBP2a ICA, and 100 and 100% for MRSA-CM in direct detection of MRSA from positive blood culture. The results of PBP2a LA test using pure colony were entirely compatible with those by mecA gene PCR but the PBP2a LA test using the pellets directly isolated from positive blood culture showed sometimes ambiguous agglutination; its sensitivity and specificity were 78 and 100%, if ambiguous results were scored as negative, and were 90 and 92%, if ambiguous results were scored as positive, respectively. CONCLUSION: For direct detection of MRSA in positive blood culture, MRSA-CM and PBP2a ICA provided excellent results. The PBP2a LA test using pure colony also gave excellent results but the PBP2a LA test by the direct method using pellet of positive blood culture was slightly less sensitive than the other two methods.

Performance of the Albicans ID2 FONT FACE=Symbol>Ò /FONT> chromogenic medium for rapid identification of Candida albicans

The aim of our study was to evaluate the accuracy of the chromogenic media Albicans ID2 FONT FACE=Symbol>Ò /FONT> (bioMérieux, France) for the identification of Candida albicans among 330 yeast strains. All C. albicans (100) and C. dubliniensis (20) strains exhibited blue color when cultured on Albicans ID2 FONT FACE=Symbol>Ò /FONT>. However, the blue color was also exhibited by cultures of C. rugosa (30/30) and C. tropicalis (3/50) isolates.

O objetivo do nosso estudo foi avaliar a eficácia do meio cromogênico Albicans ID2 FONT FACE=Symbol>Ò /FONT> (bioMérieux, France) na identificação de Candida albicans entre 330 amostras de leveduras. As cepas de C. albicans (100) e C. dubliniensis (20) exibiram coloração azul quando semeadas em Albicans ID2 FONT FACE=Symbol>Ò /FONT>. Contudo, a coloração azul também foi verificada em culturas de C. rugosa (30/30) e C. tropicalis (3/50).

Presumptive Identification of Candida Species Using Candida ID / 대한임상미생물학회지

BACKGROUND: Candida ID is introduced as a new chromogenic medium that allows presumptive identification of Candida species. We evaluated this medium to identify Candida spp. isolated from clinical specimens. METHODS: A total of 200 yeast isolates from clinical specimens in Ewha Womans University Mokdong Hospital, from April 2001 to August 2001 were identified by using the Vitek YBC (Hazelwood, Mo., USA). The results were compared with those by Candida ID (bioMeriux, Marcy l'Etoile, France). RESULTS: Candida ID correctly identified 98.0% of Candida spp. including 100% of C. albicans and 98.9% of C. tropicalis compared with the Vitek YBC. Among 84 strains showing blue colored colony on Candida ID, 82 strains (98%) were correctly identified as C. albicans but 2 strains were identified as C. glabrata and C. guilliermondii by the Vitek YBC. Among 92 strains showing pink colored colony, 90 strains (98%) were identified as C. tropicalis, and 2 strains were identified as C. guilliermondii and C. lusitaniae by the vitek YBC. CONCLUSIONS: Candida ID provides a more rapid and easier presumptive identification of major Candida spp. isolated from clinical specimens.

Primary Evaluation of the Detection Effect for Vibrio parahaemolyticus Chromogenic Medium / 微生物学通报

Vibrio parahaemolyticus is an important food-borne pathogenic bacterium that widely exists in all kinds of seafood.As the traditional media and method were very costly-time and money,a new chromogenic medium(HKC vibrio)was designed in this assay.Through detecting the artificially contaminated samples and natural samples,the sensitivity,specificity and detection effect of HKC vibrio were studied and compared with CHROMagar vibrio and TCBS.The results showed that HKC vibrio had the same sensitivity as CHROMagar vibrio and TCBS,also had highly specificity.In conclusion,HKC vibrio was an invaluable medium which may improve the detection efficiency of Vibrio parahaemolyticus dramatictly.