CRISPR-Cas systems in enterococci.

Enterococci are members of the microbiota of humans and other animals. They can also be found in the environment, associated with food, healthcare infections, and hospital settings. Due to their wide distribution, they are inserted in the One Health context. The selective pressure caused by the extensive use of antimicrobial agents in humans, animals, and agriculture has increased the frequency of resistance to various drugs among enterococcal species. CRISPR-Cas system, an important prokaryotic defense mechanism against the entry of mobile genetic elements, may prevent the acquisition of genes involved in antimicrobial resistance and virulence. This system has been increasingly used as a gene editing tool, which can be used as a way to recognize and inactivate genes of interest. Here, we conduct a review on CRISPR systems found in enterococci, considering their occurrence, structure and organization, mechanisms of action and use as a genetic engineering technology. Type II-A CRISPR-Cas systems were shown to be the most frequent among enterococcal species, and the orphan CRISPR2 was the most commonly found system (54.1%) among enterococcal species, especially in Enterococcus faecalis. Distribution of CRISPR systems varied among species. CRISPR systems had 1 to 20 spacers, with size between 23 and 37 bp and direct repeat sequences from 25 to 37 bp. Several applications of the CRISPR-Cas biotechnology have been described in enterococci, mostly in vitro, using this editing tool to target resistance- and virulence-related genes.

Occurrence of blaKPC gene in clinical isolates of Pseudomonas aeruginosa from Brazil

Pseudomonas aeruginosa is one of the main microorganisms causing healthcarerelated infections. The rise of carbapenem-resistant P. aeruginosa (CRPA) strains has become a serious public health problem. Dissemination of the enzyme Klebsiella pneumoniae carbapenemase (KPC) encoded by the blaKPC gene cause the inactivation of ß-lactam antibiotics being one of the mechanisms involved in this resistance. Given the above, the objective of this review was to evaluate the occurrence of the blaKPC gene in clinical isolates of P. aeruginosa in Brazil. For this, the online databases used were: Lilacs, SciELO and PubMed. The search for articles included articles published from 2012 to 2020, using the following keywords: blaKPC (KPC), Pseudomonas aeruginosa, and Brazil (in Portuguese and English). Initially, 30 publications eligible for inclusion in this review were identified. After the first analysis, two articles were excluded due to duplication. Subsequently, titles and abstracts were evaluated, 15 articles were excluded because they did not fit the theme, and 13 articles that met the inclusion criteria were read in full. In these studies, the presence of the blaKPC gene was investigated in 566 clinical isolates of P. aeruginosa in Brazil, with 86 (15.2%) positive samples found. Pernambuco was the state with the highest number of articles and positive samples, respectively, 38.5% (5/13), and 65.1% (56/86). This study reinforces the need to investigate the occurrence of this gene in all regions of the country in CRPA, aiming to understand how its dissemination occurs and to promote prevention and therapeutic strategies.

First report of the aac(6)-Ib-cr gene in Providencia stuartii isolates in Brazil

Abstract INTRODUCTION: The aac(6')-Ib-cr and bla KPC genes are spreading among Enterobacteriaceae species, including Providencia stuartii, in some countries of world. METHODS: These genes were investigated in 28 P. stuartii isolates from a public hospital in Recife, Pernambuco, Brazil, by PCR and sequencing. RESULTS: The aac(6')-Ib-cr gene was detected in 16 resistant isolates, and the bla KPC gene was seen in 14. CONCLUSIONS: The presence of these genes in P. stuartii multi- and extensively drug-resistant isolates indicates that the resistance arsenal of this species is increasing, thus limiting the therapeutic options.

First report of the aac(6')-Ib-cr gene in Providencia stuartii isolates in Brazil.

INTRODUCTION: The aac(6')-Ib-cr and bla KPC genes are spreading among Enterobacteriaceae species, including Providencia stuartii, in some countries of world. METHODS: These genes were investigated in 28 P. stuartii isolates from a public hospital in Recife, Pernambuco, Brazil, by PCR and sequencing. RESULTS: The aac(6')-Ib-cr gene was detected in 16 resistant isolates, and the bla KPC gene was seen in 14. CONCLUSIONS: The presence of these genes in P. stuartii multi- and extensively drug-resistant isolates indicates that the resistance arsenal of this species is increasing, thus limiting the therapeutic options.

Phenotypic and genotypic analysis of biofilm production by Pseudomonas aeruginosa isolates from infection and colonization samples.

INTRODUCTION: Pseudomonas aeruginosa is an opportunistic pathogen associated with healthcare-related infections, affecting mainly patients with underlying diseases and immunosuppression. This microorganism has several virulence mechanisms that favour its pathogenesis, including the production of biofilm. This study aimed to analyze the phenotypic production of biofilms, the occurrence of quorum sensing (QS) genes, and the clonal profile of clinical isolates of P. aeruginosa from colonized/infected patients in a tertiary hospital in Recife-PE. METHODS: We obtained 21 isolates that were classified as infection isolates (II), and 10 colonization isolates (CI). The phenotypic analysis for biofilm production was performed quantitatively. The QS genes were detected by specific PCRs, and the clonal profile was assessed using ERIC-PCR. RESULTS: Of the 31 isolates, 58.1 % (18/31) were biofilm producers, of which 70 % (7/10) were CI and classified as weakly adherent; 52.4 % (11/21) of the II produced biofilms, and were classified as weak (38.1 %, (8/21)), moderate (9.5 %, (2/21)), and strongly adherent (4.8 %, (1/21)). All isolates harbored the QS genes analyzed. In the clonal analysis, 26 distinct genetic profiles were identified, highlighting the presence of a clone in four samples, i.e., one infection isolate, and 3 colonization isolates. CONCLUSIONS: The detection of biofilm formation is important in P. aeruginosa in addition to the identification of colonization and infection isolates, especially from complex environments such as ICUs. Further, we define a strategy for monitoring and analyzing P. aeruginosa strains that can potentially cause infections in hospitalized patients.

Occurrence and Diversity of Intra- and Interhospital Drug-Resistant and Biofilm-Forming Acinetobacter baumannii and Pseudomonas aeruginosa.

Acinetobacter baumannii and Pseudomonas aeruginosa are the most relevant Gram-negative bacteria associated with hospital and opportunistic infections. This study aimed to evaluate the dynamics of drug-resistant A. baumannii and P. aeruginosa and biofilm formers from two public hospitals in northeastern Brazil. One hundred isolates (35 from A. baumannii and 65 from P. aeruginosa) were identified using the automated Vitek®2 Compact method (bioMérieux) and confirmed using the MALDI-TOF (MS) mass spectrometry technique. Molecular experiments were performed by polymerase chain reaction (PCR) to detect the frequency of blaKPC, blaIMP, blaVIM, and blaSHV genes. The biofilm formation potential was evaluated using crystal violet in Luria Bertani Miller and trypticase soy broth culture media under the following conditions: at standard concentration, one quarter (25%) of the standard concentration and supplemented with 1% glucose. In addition, the genetic diversity of the isolates was verified by the ERIC-PCR technique. Isolates presented distinct resistance profiles with a high level of beta-lactam resistance. The highest index of genes detected was blaKPC (60%), followed by blaSHV (39%), blaVIM (8%), and blaIMP (1%). All the isolates were sensitive to the polymyxins tested and formed biofilms at different intensities. Twelve clones of A. baumannii and eight of P. aeruginosa were identified, of which few were indicative of intra- and interhospital dissemination. This study reveals the dispersion dynamics of these isolates in the hospital environment. The results demonstrate the importance of monitoring programs to combat the spread of these pathogens.

Phenotypic and genotypic analysis of biofilm production by Pseudomonas aeruginosa isolates from infection and colonization samples

Abstract INTRODUCTION: Pseudomonas aeruginosa is an opportunistic pathogen associated with healthcare-related infections, affecting mainly patients with underlying diseases and immunosuppression. This microorganism has several virulence mechanisms that favour its pathogenesis, including the production of biofilm. This study aimed to analyze the phenotypic production of biofilms, the occurrence of quorum sensing (QS) genes, and the clonal profile of clinical isolates of P. aeruginosa from colonized/infected patients in a tertiary hospital in Recife-PE. METHODS: We obtained 21 isolates that were classified as infection isolates (II), and 10 colonization isolates (CI). The phenotypic analysis for biofilm production was performed quantitatively. The QS genes were detected by specific PCRs, and the clonal profile was assessed using ERIC-PCR. RESULTS: Of the 31 isolates, 58.1 % (18/31) were biofilm producers, of which 70 % (7/10) were CI and classified as weakly adherent; 52.4 % (11/21) of the II produced biofilms, and were classified as weak (38.1 %, (8/21)), moderate (9.5 %, (2/21)), and strongly adherent (4.8 %, (1/21)). All isolates harbored the QS genes analyzed. In the clonal analysis, 26 distinct genetic profiles were identified, highlighting the presence of a clone in four samples, i.e., one infection isolate, and 3 colonization isolates. CONCLUSIONS: The detection of biofilm formation is important in P. aeruginosa in addition to the identification of colonization and infection isolates, especially from complex environments such as ICUs. Further, we define a strategy for monitoring and analyzing P. aeruginosa strains that can potentially cause infections in hospitalized patients.

Occurrence of the vanA gene in Staphylococcus epidermidis from nasopharyngeal secretion of Health-Care Workers, Recife, Brazil.

INTRODUCTION: The increasing reports of vancomycin-resistant Staphylococcus strains (VRS) haves caused concern worldwide, from the laboratory detection to patient management. This study aimed to identify the occurrence of VRS strains among healthcare professionals from a university hospital. METHODS: A total of 102 Staphylococcus sp. isolates from healthcare professionals, obtained in a previous study were evaluated according to standard techniques for VRS detection. RESULTS: After screening inoculation of plates containing 6µg/ml of vancomycin, 19 resistant isolates were identified. The susceptibility profile to other antimicrobials revealed 18 multidrug resistant isolates. The minimum inhibitory concentration (MIC) was determined by E-test and broth microdilution. According to E-tests, of 19 isolates grown in BHI-V6, four isolates presented MIC ≥ 128 µg/ml, seven with MIC ranging from 4 to 8 µg/ml, and eight with MIC ≤ 2µg/ml. By broth microdilution, 14 isolates presented MIC ≤ 2 µg/ml and five with MIC ≥ 16µg/ml. The presence of the gene vanA was determined by PCR in the five resistant isolates, and this gene was detected in one of the strains. Furthermore, among the 19 strains, the gene mecA was found in 13 (39,4%) isolates, including the strain carrying the gene vanA. CONCLUSIONS: Based on these results, we highlight the presence of one strain carrying both vanA and the mecA genes, as well as multidrug-resistant strains colonizing healthcare professionals, and their importance as potential vectors to spread strains carrying resistance genes in the hospital environment.

Occurrence of the vanA gene in Staphylococcus epidermidis from nasopharyngeal secretion of Health-Care Workers, Recife, Brazil

Abstract INTRODUCTION: The increasing reports of vancomycin-resistant Staphylococcus strains (VRS) haves caused concern worldwide, from the laboratory detection to patient management. This study aimed to identify the occurrence of VRS strains among healthcare professionals from a university hospital. METHODS: A total of 102 Staphylococcus sp. isolates from healthcare professionals, obtained in a previous study were evaluated according to standard techniques for VRS detection. RESULTS: After screening inoculation of plates containing 6µg/ml of vancomycin, 19 resistant isolates were identified. The susceptibility profile to other antimicrobials revealed 18 multidrug resistant isolates. The minimum inhibitory concentration (MIC) was determined by E-test and broth microdilution. According to E-tests, of 19 isolates grown in BHI-V6, four isolates presented MIC ≥ 128 µg/ml, seven with MIC ranging from 4 to 8 µg/ml, and eight with MIC ≤ 2µg/ml. By broth microdilution, 14 isolates presented MIC ≤ 2 µg/ml and five with MIC ≥ 16µg/ml. The presence of the gene vanA was determined by PCR in the five resistant isolates, and this gene was detected in one of the strains. Furthermore, among the 19 strains, the gene mecA was found in 13 (39,4%) isolates, including the strain carrying the gene vanA. CONCLUSIONS: Based on these results, we highlight the presence of one strain carrying both vanA and the mecA genes, as well as multidrug-resistant strains colonizing healthcare professionals, and their importance as potential vectors to spread strains carrying resistance genes in the hospital environment.

Biofilm production by clinical isolates of Pseudomonas aeruginosa and structural changes in LasR protein of isolates non biofilm-producing.

INTRODUCTION: Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts. OBJECTIVES: Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS) genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates. METHODS: Isolates were tested for biofilm production by measuring cells adherence to the microtiter plates. Clonal profile analysis was carried out through ERIC-PCR, QS genes were by specific PCR. RESULTS: The results showed that 77.5% of the isolates were considered biofilm producers. The results of genotyping showed 38 distinct genetic profiles. As for the occurrence of the genes, 100% of the isolates presented the lasR, rhlI and rhlR genes, and 97.5%, presented the lasI gene. In this study nine isolates were not biofilm producers. However, all presented the QS genes. Amplicons related to genes were sequenced in three of the nine non-biofilm-producing isolates (all presenting different genetic similarity profile) and aligned to the sequences of those genes in P. aeruginosa strain PAO1 (standard biofilm-producing strain). Alignment analysis showed an insertion of three nucleotides (T, C and G) causing the addition of an amino acid valine in the sequence of the LasR protein, in position 53. CONCLUSION: The modeling of the resulting LasR protein showed a conformational change in its structure, suggesting that this might be the reason why these isolates are unable to produce biofilm.

Biofilm production by clinical isolates of Pseudomonas aeruginosa and structural changes in LasR protein of isolates non biofilm-producing

ABSTRACT Introduction: Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts. Objectives: Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS) genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates. Methods: Isolates were tested for biofilm production by measuring cells adherence to the microtiter plates. Clonal profile analysis was carried out through ERIC-PCR, QS genes were by specific PCR. Results: The results showed that 77.5% of the isolates were considered biofilm producers. The results of genotyping showed 38 distinct genetic profiles. As for the occurrence of the genes, 100% of the isolates presented the lasR, rhlI and rhlR genes, and 97.5%, presented the lasI gene. In this study nine isolates were not biofilm producers. However, all presented the QS genes. Amplicons related to genes were sequenced in three of the nine non-biofilm-producing isolates (all presenting different genetic similarity profile) and aligned to the sequences of those genes in P. aeruginosa strain PAO1 (standard biofilm-producing strain). Alignment analysis showed an insertion of three nucleotides (T, C and G) causing the addition of an amino acid valine in the sequence of the LasR protein, in position 53. Conclusion: The modeling of the resulting LasR protein showed a conformational change in its structure, suggesting that this might be the reason why these isolates are unable to produce biofilm.

Analysis of biofilm production by clinical isolates of Pseudomonas aeruginosa from patients with ventilator-associated pneumonia. / Análise da produção de biofilme por isolados clínicos de Pseudomonas aeruginosa de pacientes com pneumonia associada à ventilação mecânica.

OBJECTIVE: To phenotypically evaluate biofilm production by Pseudomonas aeruginosa clinically isolated from patients with ventilator-associated pneumonia. METHODS: Twenty clinical isolates of P. aeruginosa were analyzed, 19 of which were from clinical samples of tracheal aspirate, and one was from a bronchoalveolar lavage sample. The evaluation of the capacity of P. aeruginosa to produce biofilm was verified using two techniques, one qualitative and the other quantitative. RESULTS: The qualitative technique showed that only 15% of the isolates were considered biofilm producers, while the quantitative technique showed that 75% of the isolates were biofilm producers. The biofilm isolates presented the following susceptibility profile: 53.3% were multidrug-resistant, and 46.7% were multidrug-sensitive. CONCLUSION: The quantitative technique was more effective than the qualitative technique for the detection of biofilm production. For the bacterial population analyzed, biofilm production was independent of the susceptibility profile of the bacteria, demonstrating that the therapeutic failure could be related to biofilm production, as it prevented the destruction of the bacteria present in this structure, causing complications of pneumonia associated with mechanical ventilation, including extrapulmonary infections, and making it difficult to treat the infection.

OBJETIVO: Avaliar fenotipicamente a produção de biofilme por isolados clínicos de Pseudomonas aeruginosa de pacientes com pneumonia associada à ventilação mecânica. MÉTODOS: Foram analisados 20 isolados clínicos de P. aeruginosa, sendo 19 provenientes de amostras clínicas de aspirado traqueal e uma de lavado broncoalveolar. A avaliação da capacidade de P. aeruginosa em produzir biofilme foi verificada por duas técnicas, sendo uma qualitativa e outra quantitativa. RESULTADOS: A técnica qualitativa mostrou que apenas 15% dos isolados foram considerados produtores de biofilme, enquanto que a quantitativa demonstrou que 75% dos isolados foram produtores de biofilme. Os isolados produtores de biofilme apresentaram o seguinte perfil de suscetibilidade: 53,3% eram multidroga-resistentes e 46,7% eram multidroga-sensíveis. CONCLUSÃO: A técnica quantitativa foi mais eficaz para detecção da produção de biofilme em comparação com a qualitativa. Para a população bacteriana analisada, a produção de biofilme independeu do perfil de suscetibilidade das bactérias, demonstrando que a falha terapêutica pode estar relacionada com a produção de biofilme, por impedir a destruição das bactérias presentes nesta estrutura, ocasionando complicações da pneumonia associada à ventilação mecânica, incluindo infecções extrapulmonares, e dificultando o tratamento da infecção.

Análise da produção de biofilme por isolados clínicos de Pseudomonas aeruginosa de pacientes com pneumonia associada à ventilação mecânica / Analysis of biofilm production by clinical isolates of Pseudomonas aeruginosa from patients with ventilator-associated pneumonia

RESUMO Objetivo: Avaliar fenotipicamente a produção de biofilme por isolados clínicos de Pseudomonas aeruginosa de pacientes com pneumonia associada à ventilação mecânica. Métodos: Foram analisados 20 isolados clínicos de P. aeruginosa, sendo 19 provenientes de amostras clínicas de aspirado traqueal e uma de lavado broncoalveolar. A avaliação da capacidade de P. aeruginosa em produzir biofilme foi verificada por duas técnicas, sendo uma qualitativa e outra quantitativa. Resultados: A técnica qualitativa mostrou que apenas 15% dos isolados foram considerados produtores de biofilme, enquanto que a quantitativa demonstrou que 75% dos isolados foram produtores de biofilme. Os isolados produtores de biofilme apresentaram o seguinte perfil de suscetibilidade: 53,3% eram multidroga-resistentes e 46,7% eram multidroga-sensíveis. Conclusão: A técnica quantitativa foi mais eficaz para detecção da produção de biofilme em comparação com a qualitativa. Para a população bacteriana analisada, a produção de biofilme independeu do perfil de suscetibilidade das bactérias, demonstrando que a falha terapêutica pode estar relacionada com a produção de biofilme, por impedir a destruição das bactérias presentes nesta estrutura, ocasionando complicações da pneumonia associada à ventilação mecânica, incluindo infecções extrapulmonares, e dificultando o tratamento da infecção.

ABSTRACT Objective: To phenotypically evaluate biofilm production by Pseudomonas aeruginosa clinically isolated from patients with ventilator-associated pneumonia. Methods: Twenty clinical isolates of P. aeruginosa were analyzed, 19 of which were from clinical samples of tracheal aspirate, and one was from a bronchoalveolar lavage sample. The evaluation of the capacity of P. aeruginosa to produce biofilm was verified using two techniques, one qualitative and the other quantitative. Results: The qualitative technique showed that only 15% of the isolates were considered biofilm producers, while the quantitative technique showed that 75% of the isolates were biofilm producers. The biofilm isolates presented the following susceptibility profile: 53.3% were multidrug-resistant, and 46.7% were multidrug-sensitive. Conclusion: The quantitative technique was more effective than the qualitative technique for the detection of biofilm production. For the bacterial population analyzed, biofilm production was independent of the susceptibility profile of the bacteria, demonstrating that the therapeutic failure could be related to biofilm production, as it prevented the destruction of the bacteria present in this structure, causing complications of pneumonia associated with mechanical ventilation, including extrapulmonary infections, and making it difficult to treat the infection.

Phenotypic and molecular characterization of resistance to macrolides, lincosamides and type B streptogramin of clinical isolates of Staphylococcus spp. of a university hospital in Recife, Pernambuco, Brazil

Abstract Introduction There is a mechanism of macrolide resistance in Staphylococcus spp. which also affects the lincosamides and type B streptogramins characterizing the so-called MLSB resistance, whose expression can be constitutive (cMLSB) or inducible (iMLSB) and is encoded mainly by ermA and ermC genes. The cMLSB resistance is easily detected by susceptibility testing used in the laboratory routine, but iMLSB resistance is not. Therapy with clindamycin in cases of infection with isolated iMLSB resistance may fail. Objective To characterize the phenotypic (occurrence of cMLSB and iMLSB phenotypes) and molecular (occurrence of ermA and ermC genes) profiles of MLSB resistance of clinical isolates of susceptible and methicillin-resistant Staphylococcus aureus and CNS (coagulase-negative Staphylococcus) from patients of a university hospital, in Pernambuco. Methods The antimicrobial susceptibility of 103 isolates was determined by the disk diffusion technique in Mueller–Hinton agar followed by oxacillin screening. The iMLSB phenotype was detected by D test. Isolates with cMLSB and iMLSB phenotypes were subjected to polymerase chain reaction (PCR) for the detection of ermA and ermC genes. Results The cMLSB and iMLSB phenotypes were respectively identified in 39 (37.9%) and five (4.9%) isolates. The iMLSB phenotype was found only in four (10.8%) methicillin-susceptible S. aureus and one (4.5%) methicillin-resistant S. aureus. In the 44 isolates subjected to PCR, four (9.1%) only ermA gene was detected, a lower frequency when compared to only ermC 17 (38.6%) gene and to one (2.3%) isolate presenting both genes. Conclusion In the Staphylococcus spp. analyzed, the ermC gene was found more often than the ermA, although the iMLSB phenotype had been less frequent than the cMLSB. It was important to perform the D test for its detection to guide therapeutic approaches.

Detection of blaSPM-1, blaKPC, blaTEM and blaCTX-M genes in isolates of Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella spp. from cancer patients with healthcare-associated infections.

Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella spp. are three of the pathogens most frequently involved in infections of cancer patients, and the production of ß -lactamases is a major mechanism of resistance due to its wide diversity of existing enzymes. Therefore, the aim of the present study was to investigate the microbiological profile and data related to patients and infections, and to search for ß -lactamase genes in bacterial isolates from hospitalized cancer patients in a hospital in Recife, Pernambuco, Brazil. A total of 169 isolates were recovered between 2012 and 2014, of which 58 were P. aeruginosa, 36 were Acinetobacter spp. and 75 were Klebsiella spp. A high percentage of carbapenem resistance was observed in P. aeruginosa and Acinetobacter spp. Among the carbapenem-resistant bacteria, the blaSPM-1 gene was detected in P. aeruginosa (35.5 %) and Acinetobacter spp. (3.8 %), while blaKPC was detected in P. aeruginosa (25.8 %) only. Among the third- and fourth-generation cephalosporin-resistant strains, in Klebsiella spp. we detected the genes blaTEM (30.6 %), blaCTX-M (58.3 %) and blaKPC (5.6 %), and in Acinetobacter spp. only blaTEM (25.9 %). This the first report of an Acinetobacter baumannii blaSPM-1 gene carrier that has been isolated in Brazil. The most frequent cancer types were bowel tumour [14.8 %; 95 % confidence interval (CI95 %) 9.8-21.1 %], breast cancer (13.6 %; CI95 % 8.8-19.7 %) and prostate cancer (11.2%; CI95 % 6.9-17.0 %). These results therefore provide knowledge of susceptibility profile and resistance mechanisms and thus can contribute to the strategic formulation of hospital infection control plans and the rational use of antimicrobials, reducing mortality from infection levels in cancer patients.

Phenotypic and molecular characterization of resistance to macrolides, lincosamides and type B streptogramin of clinical isolates of Staphylococcus spp. of a university hospital in Recife, Pernambuco, Brazil.

INTRODUCTION: There is a mechanism of macrolide resistance in Staphylococcus spp. which also affects the lincosamides and type B streptogramins characterizing the so-called MLSB resistance, whose expression can be constitutive (cMLSB) or inducible (iMLSB) and is encoded mainly by ermA and ermC genes. The cMLSB resistance is easily detected by susceptibility testing used in the laboratory routine, but iMLSB resistance is not. Therapy with clindamycin in cases of infection with isolated iMLSB resistance may fail. OBJECTIVE: To characterize the phenotypic (occurrence of cMLSB and iMLSB phenotypes) and molecular (occurrence of ermA and ermC genes) profiles of MLSB resistance of clinical isolates of susceptible and methicillin-resistant Staphylococcus aureus and CNS (coagulase-negative Staphylococcus) from patients of a university hospital, in Pernambuco. METHODS: The antimicrobial susceptibility of 103 isolates was determined by the disk diffusion technique in Mueller-Hinton agar followed by oxacillin screening. The iMLSB phenotype was detected by D test. Isolates with cMLSB and iMLSB phenotypes were subjected to polymerase chain reaction (PCR) for the detection of ermA and ermC genes. RESULTS: The cMLSB and iMLSB phenotypes were respectively identified in 39 (37.9%) and five (4.9%) isolates. The iMLSB phenotype was found only in four (10.8%) methicillin-susceptible S. aureus and one (4.5%) methicillin-resistant S. aureus. In the 44 isolates subjected to PCR, four (9.1%) only ermA gene was detected, a lower frequency when compared to only ermC 17 (38.6%) gene and to one (2.3%) isolate presenting both genes. CONCLUSION: In the Staphylococcus spp. analyzed, the ermC gene was found more often than the ermA, although the iMLSB phenotype had been less frequent than the cMLSB. It was important to perform the D test for its detection to guide therapeutic approaches.

Infection by multidrug-resistant Elizabethkingia meningoseptica: case reports / Infecção por Elizabethkingia meningoseptica multirresistente: relato de casos

We report two cases of sepsis in critically ill patients in two tertiary care hospitals in Recife-PE, Brazil. The first case is an 87-year-old patient with chronic myeloid leukemia and sepsis; and the second case is a 93-year-old patient with prostate cancer and septic shock caused by multidrug-resistant (MDR) Elizabethkingia meningoseptica.

Reportamos dois casos de sepse em pacientes criticamente debilitados em dois hospitais com nível de complexidade terciária em Recife-PE, Brasil. O primeiro caso, paciente de 87 anos com leucemia mieloide crônica e sepse; o segundo, paciente com 93 anos de idade com câncer de próstata apresentava choque séptico causado por Elizabethkingia meningoseptica multirresistente.

The occurrence and dissemination of methicillin and vancomycin-resistant Staphylococcus in samples from patients and health professionals of a university hospital in Recife, State of Pernambuco, Brazil.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) strains have been responsible for many nosocomial outbreaks. Within hospitals, colonized employees often act as reservoirs for the spread of this organism. This study collected clinical samples of 91 patients admitted to the intensive care unit (ICU), hemodialysis/nephrology service and surgical clinic, and biological samples from the nasal cavities of 120 professionals working in those environments, of a University Hospital in Recife, in the State of Pernambuco, Brazil. The main objective of this study was to determine the occurrence and dissemination of methicillin- and vancomycin-resistant Staphylococcus spp. METHODS: The isolates obtained were tested for susceptibility to oxacillin and vancomycin and detection of the mecA gene. In addition, the isolates were evaluated for the presence of clones by ribotyping-polymerase chain reaction (PCR). RESULTS: MRSA occurrence, as detected by the presence of the mecA gene, was more prevalent among nursing technicians; 48.1% (13/27) and 40.7% (11/27) of the isolates were from health professionals of the surgical clinic. In patients, the most frequent occurrence of mecA-positive isolates was among the samples from catheter tips (33.3%; 3/9), obtained mostly from the hemodialysis/nephrology service. Eight vancomycin-resistant strains were found among the MRSA isolates through vancomycin screening. Based on the amplification patterns, 17 ribotypes were identified, with some distributed between patients and professionals. CONCLUSIONS: Despite the great diversity of clones, which makes it difficult to trace the source of the infection, knowledge of the molecular and phenotypic profiles of Staphylococcus samples can contribute towards guiding therapeutic approaches in the treatment and control of nosocomial infections.