The rise of multidrug resistant Salmonella isolates in healthy chickens in Brazil by successful establishment of plasmid IncHI2A carrying several antibiotic resistance genes.

Salmonella spp. is an important global issue in food-producing animals. The present study evaluated antimicrobial resistance and virulence profiles in Salmonella spp. isolates from chickens in Brazil. Identification of serotypes, virulence and antimicrobial resistance genes, and plasmid profiles were performed. Three different serovars were found, S. Schwarzengrund, S. Newport and S. Kentucky. All isolates were considered Multidrug- resistance (MDR). Among the 32 Salmonella spp. isolates analysed, 29 isolates carried blaCTX-M-2 gene and showed the insertion sequence ISCR1 and a class 1 integron structure upstream from blaCTX-M-2. This gene was harboured in large IncHI2A plasmids with approximately 280kb. Furthermore, 30 isolates harboured tetA and tetB genes and 25 also harboured qnrB. The virulence genes invA, misL, orfL, spiC and pipD were detected in all isolates. The study shows a high prevalence of MDR Salmonella isolates disseminated in poultry farms. The association of the replicon IncHI2A with the resistance genes found, elevate the risk of foodborne disease outbreaks.

Gram-negative bacteria carrying ß-lactamase encoding genes in hospital and urban wastewater in Brazil.

Multidrug resistance mediated by ß-lactamase in Gram-negative bacilli is a serious public health problem. Sewers are considered reservoirs of multiresistant bacteria due to presence of antibiotics that select them and favor their dissemination. The present study evaluated the antibiotic resistance profile and ß-lactamases production in Gram-negative bacilli isolates from hospital sewage and urban wastewater treatment plants (UWWTP) in Brazil. Bacteria were isolated and identified with biochemical tests. Antibiotic susceptibility testing was performed by the disk-diffusion method and detection of extended-spectrum ß-lactamase and carbapenemases by enzymatic inhibitor and conventional PCR. Differences in resistance to amoxicillin clavulanic, aztreonam, cefepime, and cefotaxime were observed in hospital sewage compared with urban sewage (p < 0.05). The multidrug-resistant phenotype was observed in 33.3% of hospital sewage isolates (p = 0.0025). ß-lactamases genes were found in 35.6% of isolates, with the most frequent being blaKPC and blaTEM (17.8%), and blaSHV and blaCTX-M (13.3% and 8.9%, respectively). The data obtained are relevant, since the bacteria detected are on the priority pathogens list from the World Health Organization and hospital sewage could be released untreated into the municipal collection system, which may favor the spread of resistance. Changes in hospital sewage discharge practices, as well as additional technologies regarding effluent disinfection in the UWWTP, can prevent the spread of these bacteria into the environment and negative impact on water resources.

Adaptation of Pseudomonas aeruginosa to the chronic phenotype by mutations in the algTmucABD operon in isolates from Brazilian cystic fibrosis patients.

Chronic lung infection by Pseudomonas aeruginosa is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. This is associated with the conversion of the non-mucoid to the mucoid phenotype. However, there is little information about the occurrence of alginate-producing P. aeruginosa in CF patients outside Europe and North America. The aim of the present study was to investigate mutations in the algTmucABD operon in mucoid and non-mucoid isolates from Brazilian CF patients. Twenty-seven mucoid and 37 non-mucoid isolates from 40 CF patients chronically infected by P. aeruginosa attending a CF reference center in Brazil were evaluated by sequence analysis. Mutations in mucA were observed in 93% of the mucoid isolates and 54% of the non-mucoid isolates. Among these non-mucoid isolates, 55% were considered revertants, since they also had mutations in algT (algU). Most isolates associated with moderate alginate production presented point mutations in mucB and/or mucD. We identified 30 mutations not previously described in the operon. In conclusion, mutations in mucA were the main mechanism of conversion to mucoidy, and most of the non-mucoid isolates were revertants, but the mechanism of revertance is not fully explained by changes in algT.

Draft genome sequence of a KPC-2-producing Klebsiella pneumoniae ST340 carrying blaCTX-M-15 and blaCTX-M-59 genes: a rich genome of mobile genetic elements and genes encoding antibiotic resistance.

OBJECTIVES: Klebsiella pneumoniae is considered an opportunistic pathogen and an important agent of nosocomial and community infections. It presents the ability to capture and harbour several antimicrobial resistance genes and, in this context, the extensive use of carbapenems to treat serious infections has been responsible for the selection of several resistance genes. This study reports the draft genome sequence of a KPC-2-producing K. pneumoniae strain (Kp10) simultaneously harbouring blaCTX-M-15 and blaCTX-M-59 genes isolated from urine culture of a patient with Parkinson's disease. METHODS: Classical microbiological methods were applied to isolate and identify the strain, and PCR and sequencing were used to identify and characterise the genes and the genetic environment. Whole-genome sequencing (WGS) was performed using a Nextera XT DNA library and a NextSeq platform. RESULTS: WGS analysis revealed the presence of 5915 coding genes, 46 RNA-encoding genes and 255 pseudogenes. Kp10 belonged to sequence type 340 (ST340) of clonal complex 258 (CC258) and carried 20 transferable genes associated with antimicrobial resistance, comprising seven drug classes. Although the simultaneous presence of different blaCTX-M genes in the same strain is rarely reported, the blaKPC-2, blaCTX-M-15 and blaCTX-M-59 genes were not associated with the same genetic mobile structure in Kp10. CONCLUSIONS: These results confirm the capacity of K. pneumoniae to harbour several antimicrobial resistance genes. Thus, this draft genome could help in future epidemiological studies regarding the dissemination of clinically relevant resistance genes.

Transfer of KPC-2 carbapenemase from Klebsiella pneumoniae to Enterobacter cloacae in a patient receiving meropenem therapy.

The horizontal transfer of a plasmid bearing the blaKPC-2 gene from K. pneumoniae to E. cloacae infecting the respiratory tract of a patient during meropenem therapy was elucidated. This finding is particularly worrisome, since these drugs are of last resort for multidrug-resistant Gram-negative pathogens.

Relationship between nasal colonization and ventilator-associated pneumonia and the role of the environment in transmission of Staphylococcus aureus in intensive care units.

BACKGROUND: This study assessed the relationship between nasal colonization and ventilator-associated pneumonia (VAP) by Staphylococcus aureus, as well the role of the environment in the transmission of this organism. METHODS: We performed a cohort study of patients with VAP caused by methicillin-resistant S aureus (MRSA) or methicillin-sensitive S aureus during 2 years in an adult intensive care unit (ICU). All patients had nasal swab specimens obtained at admission and during the ICU stay. Clinical samples also were collected for analysis, as were samples from the hands of health care professionals and the environment, and were typed using pulsed-field gel electrophoresis. RESULTS: S aureus VAP represented 12.5% of the cases, and statistical analysis identified colonization as a risk factor for the development of this infection. MRSA was isolated from the environment and hands, indicating the existence of a secondary reservoir. Molecular typing revealed a polyclonal profile; however, clone J was the most frequent (45.5%) among isolates of MRSA tested, with a greater profile of resistance than the other isolates. There was strong evidence suggesting transmission of MRSA to patients from the environment. CONCLUSION: Nasal colonization for S aureus is a risk factor for development of VAP.

Clonal complexes 104, 109 and 113 playing a major role in the dissemination of OXA-carbapenemase-producing Acinetobacter baumannii in Southeast Brazil.

Carbapenem resistance among Acinetobacter baumannii strains isolated from clinical settings in Brazil has increased dramatically in the last 10 years due to the emergence and dissemination of OXA-type carbapenemase encoding genes. This study aimed to characterize the presence of carbapenem-hydrolyzing class D ß-lactamases (CHDL)-encoding genes and clonal complexes playing a major role in the dissemination of OXA-carbapenemase-producing A. baumannii in Southeast Brazil. A total of 74 A. baumannii strains isolated from patients admitted to 4 hospitals in Southeast Brazil were analyzed. Molecular characterization of strains revealed that 67 strains carried blaOXA-23 (72%), blaOXA-143 (25%) or both genes (3%). PFGE analysis identified 12 PFGE clusters, grouping 26 pulsotypes. Two PFGE clusters were predominant, comprising more than 66% of OXA-producing A. baumannii isolates. Among 23 representative strains characterized by MLST-UO (Multilocus Sequence Typing Scheme - University of Oxford, http://pubmlst.org/abaumannii/), 14 different STs were identified, of which six were confirmed as novel sequence types (designated as STs 402-407). Most of these isolates belonged to clonal complexes CC104,CC109 or CC113, whereas three STs were singletons (ST339, 403 and 407). In conclusion, the presence of blaOXA-23- and blaOXA-143-like genes was not related to specific ST/CC, suggesting that the dissemination of OXA-carbapenemase-encoding genes may involve different STs, in which the spread of OXA-23-like is most likely due to mobile elements (i.e., plasmids). In this regard, CC104, CC109 and CC113 played a major role as predominant CDHL-carrying clones, instead of CC92, which was not identified.

Genetic features and molecular epidemiology of Enterococcus faecium isolated in two university hospitals in Brazil.

The global emergence of vancomycin-resistant Enterococcus faecium (VREfm) has been characterized by a clonal spread of strains belonging to clonal complex 17 (CC17). Genetic features and clonal relationships of 53 VREfm isolated from patients in 2 hospitals in Ribeirao Preto, São Paulo, Brazil, during 2005-2010 were determined as a contribution to the Brazilian evolutionary history of these nosocomial pathogens. All isolates were daptomycin susceptible, vancomycin-resistant, and had the vanA gene. The predominant virulence genes were acm and esp. Only 5 VREfm isolated in 2005-2006 had intact Tn1546, while 81% showed Tn1546 with deleted left extremity and insertion of IS1251 between the vanS and vanH genes. Multilocus sequence typing analysis permitted the identification of 9 different sequence types (STs), with 5 being new ones (656, 657, 658, 659, and 660). Predominant STs were ST412 and ST478, all belonging to CC17, except ST658. This is the first report of the ST78 in Brazil.

Prevalência de Staphylococcus aureus na saliva de trabalhadores de saúde / Prevalence of Staphylococcus aureus in saliva of healthcare workers

Introdução: O estado de portador de Staphylococcus aureus resistente à meticilina é apontado como preditor de infecção e fator para a disseminação ambiental e de pessoa a pessoa, incluindo trabalhadores de serviço de saúde. Estes quando colonizados são freqüentemente associados a surtos. Objetivo: Analisar a prevalência de Staphylococcus aureus na saliva de trabalhadores de hospital universitário. Metodologia: Estudo epidemiológico longitudinal realizado em Curitiba, Paraná, Brasil, com 486 trabalhadores no período de abril de 2006 a junho de 2008 compreendeu a coleta de três amostras de saliva e aplicação de instrumento de coletade dados. Staphylococcus aureus foram isolados dos espécimes clínicos e caracterizados fenotipicamente. Os dados foram organizados e processados no Programa EPI-Info e analisados por meio de estatística descritiva. Resultados: Entre os trabalhadores investigados, 60,9 por cento estavam colonizados por Staphylococcus aureus na saliva,sendo 67.9 por cento carreadores transitórios e 32.1 por cento carreadores persistentes; a prevalência de Staphylococcus aureus resistenteà meticilina (MRSA) entre os isolados foi de 15.7 por cento. A prevalência média de MRSA foi de 12.7 por cento sendo maior entre técnicos em enfermagem (21.4 por cento) e auxiliares de limpeza (20.6 por cento) e menor entre enfermeiros (4.5 por cento) e médicos (5.9 por cento). Conclusões: Os trabalhadores apresentaram alta prevalência de Staphylococcus aureus na saliva, indicando a boca como importante sítio corporal para a investigação da colonização por MRSA e potencial fonte para sua disseminação.

Background: The carrier state of methicillin-resistant Staphylococcus aureus is pointed as an infection predictor and a factor for environmental and person-to-person dissemination, including health service workers. These, when colonized are commonly associated to outbreaks. Objective: Analyze the prevalence of Staphylococcus aureus in saliva of workers at a university hospital.Methodology: Epidemiologic longitudinal study carried out in Curitiba, Paraná, Brazil, with 486 workers between April2006 and June 2008. Three saliva samples were collected and a data collection instrument was applied. Staphylococcus aureus were isolated from the clinical specimen and characterized by phenotypes. The data from the instrument and the laboratory results were organized and processed with EPIInfo software and analyzed via descriptive statistics. Results: Among the healthcare workers studied, 60.9%were colonized by Staphylococcus aureus in saliva; of those, 67.9% were transitory carriers and 32.1% were persistent carriers; the prevalence of meticillin-resistant Staphylococcusaureus (MRSA) among the isolated cases was 15.7%. The average prevalence of MRSA was 12.7% and higher among nurses’ aides (21.4%) and cleaning aides (20.6%) and loweramong nurses (4.5%) and doctors (5.9%). Conclusions: Healthcare workers presented high prevalence of Staphylococcus aureus in saliva, indicating the mouth as an important body site to investigate colonizationby MRSA and a potential source to its dissemination.

CTX-M-producing Klebsiella spp. in a Brazilian hospital: what has changed in 6 years?

CTX-M-encoding genes from Klebsiella spp. strains isolated in 2000 and 2006 were characterized as well as their genetic environment. CTX-M-2 variants were predominant in Klebsiella pneumoniae strains, which showed a greater variability in bla(CTX-M) genes, integrons, and plasmids in 2006 when compared to strains collected in 2000. CTX-M-9-producing Klebsiella oxytoca was identified in 2000 as clonal dissemination.

First report of vancomycin-resistant enterococcus faecalis in Uberaba, Minas gerais state.

In this study we report the first isolation of VanA-type vancomycin-resistant Enterococcus faecalis strains from two different patients hospitalized in the same intensive care unit at the hospital of Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.

Nosocomial outbreak by imipenem-resistant metallo-beta-lactamase-producing Pseudomonas aeruginosa in an adult intensive care unit in a Brazilian teaching hospital.

OBJECTIVE: To describe an outbreak of imipenem-resistant metallo-beta-lactamase-producing Pseudomonas aeruginosa, enzyme type bla, by horizontal transmission in patients admitted to a mixed adult ICU. METHODS: A case-control study was carried out, including 47 patients (cases) and 122 patients (control) admitted to the mixed ICU of a university hospital in Minas Gerais, Brazil from November 2003 to July 2005. The infection site, risk factors, mortality, antibiotic susceptibility, metallo-beta-lactamase (MBL) production, enzyme type, and clonal diversity were analyzed. RESULTS: A temporal/spatial relationship was detected in most patients (94%), overall mortality was 55.3%, and pneumonia was the predominant infection (85%). The majority of isolates (95%) were resistant to imipenem and other antibiotics, except for polymyxin, and showed MBL production (76.7%). Only bla SPM-1 (33%) was identified in the 15 specimens analyzed. In addition, 4 clones were identified, with a predominance of clone A (61.5%) and B (23.1%). On multivariate analysis, advanced age, mechanical ventilation, tracheostomy, and previous imipenem use were significant risk factors for imipenem-resistant P. aeruginosa infection. CONCLUSIONS: Clonal dissemination of MBL-producing P. aeruginosa strains with a spatial/temporal relationship disclosed problems in the practice of hospital infection control, low adherence to hand hygiene, and empirical antibiotic use.

An outbreak of Acinetobacter baumannii septicemia in a neonatal intensive care unit of a university hospital in Brazil.

We studied an outbreak of two multi-drug resistant clones of Acinetobacter baumannii in the Neonatal Intensive Care Unit of the Uberlândia Federal University Hospital in Minas Gerais state, Brazil, and we analyzed the contribution of cross-transmission in the rise in infection rates. Eleven neonates who developed multi-drug resistant A. baumannii nosocomial infection were matched to 22 neonates who were admitted to the same unit and did not develop an infection during the outbreak period, in order to identify risk factors for infection. Three out of the 11 neonates died. Epidemiological investigation included molecular typing, using pulsed field gel electrophoresis. Prior to the outbreak, from December 2001 to March 2002, no case of infection by this microorganism was diagnosed. Environmental and healthcare worker hand cultures were negative. Nine isolates had similar pulsed field gel electrophoresis patterns and two had another clone. The first clone was brought into the unit by an infected patient who was transferred from another hospital without a history of antibiotic use. The second clone did have its origin clearly defined. Both infected groups led us to conclude that several factors contributed to infection with A. baumannii. These factors were: exposure to antibiotics and invasive devices, birth weight < 1500 g, age < or = 7 days and duration of hospitalization > or = 7 days. Based on logistic regression, infected neonates were more exposed to carbapenem and mechanical ventilation than the control group. Cross transmission between infants contributed to the rise in the rates of multi-drug resistant A. baumannii infection.