Marcelo Pilonetto

Hospital gowns as a vehicle for bacterial dissemination in an intensive care unit

The microbiota from the uniforms of 31 professionals from the general intensive care unit was analyzed. The samples were collected in duplicate at the beginning and at the end of the work period. Total viable counts of microorganisms were determined; there was a significant increase in the counts at the end of the period, when compared with those obtained at the beginning. No significant difference was observed between the first and second counts obtained from the cuffs. However, differences were observed for the samples from the abdominal region. Among the isolated pathogens 11/18 were Staphylococcus aureus, 2/18 were Acinetobacter baumannii, 2/18 were Klebsiela pneumoniae and 1/18 were Serratia rubidae. Some of these isolates were multi-resistant to antibiotics. Emphasis should be placed on reducing the spread of these pathogens in the hospital, making sure that biosafety protocols are followed by the staff.

Risk factors for KPC-producing Klebsiella pneumoniae bacteremia

The molecular epidemiology of carbapenemase-producing Klebsiella pneumoniae (KPC) has been largely investigated, but limited clinical information is available. A case-control study was performed to evaluate the risk factors for KPC bacteremia in hospitalized patients. Cases were patients with KPC bacteremia and controls were patients with non-KPC bacteremia. A total of 85 patients were included, 18 (21.2%) were KPC, and 67 (78.8%) were non-KPC (40 [59.7%] of them were extended-spectrum beta-lactamase producers). All KPC isolates were type 2 producers. These isolates belong to five distinct clones. Multivariate analysis showed that age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02 - 1.11; p = 0.004), presence of mechanical ventilation (OR, 11.1; 95% CI, 1.92 - 63.3; p = 0.007) and fluoroquinolone exposure during hospitalization (OR, 28.9; 95% CI, 1.85 - 454.6; p = 0.02) were independent risk factors for KPC in patients with K. pneumoniae bacteremia. Factors associated with severity of illness, such as age and mechanical ventilation, seem to be the main risks factors for KPC. Fluoroquinolones use might be a risk factor for KPC bacteremia. Further investigations on risk factors for KPC are warranted.

Molecular epidemiology characterization of OXA-23 carbapenemase-producing Acinetobacter baumannii isolated from 8 Brazilian hospitals using repetitive sequence–based PCR

The typing of multidrug-resistant Acinetobacter baumannii isolates is important for the control and prevention of hospital outbreaks. This study aimed to analyze the molecular epidemiology of 46 OXA-23 carbapenemase-producing A. baumannii strains and compare them to previously described local and international clones (ICs). Isolates were recovered during May 2009-August 2011, from 8 different hospitals in the state of Parana (Brazil). The molecular profiles were determined by repetitive extragenic palindromic PCR. Seven different clusters were identified (A to G). Thirty-two isolates were clustered in the same pattern (clone A), which belong to IC 4.

Effects of low intensity laser in in vitro bacterial culture and in vivo infected wounds

OBJECTIVE to compare the effects of low intensity laser therapy on in vitro bacterial growth and in vivo in infected wounds, and to analyze the effectiveness of the AsGa Laser technology in in vivo wound infections. METHODS in vitro: Staphylococcus aureus were incubated on blood agar plates, half of them being irradiated with 904 nm wavelength laser and dose of 3J/cm² daily for seven days. In vivo: 32 male Wistar rats were divided into control group (uninfected) and Experimental Group (Infected). Half of the animals had their wounds irradiated. RESULTS in vitro: there was no statistically significant variation between the experimental groups as for the source plates and the derived ones (p>0.05). In vivo: there was a significant increase in the deposition of type I and III collagen in the wounds of the infected and irradiated animals when assessed on the fourth day of the experiment (p=0.034). CONCLUSION low-intensity Laser Therapy applied with a wavelength of 904 nm and dose 3J/cm² did not alter the in vitro growth of S. aureus in experimental groups; in vivo, however, it showed significant increase in the deposition of type I and III collagen in the wound of infected and irradiated animals on the fourth day of the experiment.

Infection on the meshes implantation area in the abdominal wall of rats with induced bacterial peritonitis

PURPOSE: Evaluate incidence of bacterial growth on implanted meshes in the abdominal wall of rats after to induce bacterial peritonitis. METHODS: 36 rats were used. They were allocated in two groups: group B, experiment group (n =18) and group S, control group (n =18). They were submitted to the implant of polypropylene meshes on the abdominal wall, at the preperitoneal space. Then, in the animals of the experiment group, the induction of peritonitis was made through the inoculation in the peritoneal cavity of standardized solution of Escherichia coli. In the animals of the control group it was made through the inoculation of physiologic solution. The animals of both groups were reallocated in three subgroups of six animals and observed until the reoperations time, for evaluation of the implantation sites, collection of the meshes for cultures, evaluation of the abdominal cavity and peritoneal lavage for cultures. The reoperations occurred in 24, 48 and 72 hours. RESULTS: All the animals of the experiment group presented clinical symptoms of peritonitis. The cultures of the meshes taken off from the implantation sites were positive in 83% of the animals when the moment of the evaluations was of 24 hours, decreasing to 33% in 48 hours and 17% in 72 hours. Globally, it was of 44%. In the animals of the control group there was no case of positive culture neither in the meshes, nor in the peritoneal lavages. CONCLUSIONS: The experimental model used was effective, producing 100% of peritonitis. The incidence of bacterial growth on the implanted polypropylene meshes was 83% in 24 hours, decreasing with the time.

Molecular epidemiology of SPM-1-producing Pseudomonas aeruginosa by rep-PCR in hospitals in Parana, Brazil ☆

BACKGROUND Infections caused by multidrug resistant microorganisms are a global health problem, and Pseudomonas aeruginosa is an important nosocomial pathogen, easily disseminated in the hospital environment. The aim of this study was to determine SPM-1 in P. aeruginosa strains in 30 Brazilian hospitals and the genetic similarity of isolates. METHODS We analyzed 161 isolates of carbapenem-resistant P. aeruginosa. Imipenem/EDTA and imipenem strip were used for phenotypic detection of MBL production; and real-time polymerase chain reaction (PCR) for genetic detection. Genetic similarity was determined by rep-PCR. RESULTS We obtained 136/161 (84.5%) isolates with positive phenotypic result for metallo-β-lactamase (MBL) and the blaSPM-1 gene was identified in 41 isolates. There was a predominant profile (>95% of genetic similarity) in 92.7% of isolates. This predominant profile was widely disseminated in Paraná state. CONCLUSION SPM-1 is the main MBL identified in carbapenem-resistant P. aeruginosa in Southern Brazil. The genetic similarity among some isolates suggests a clonal expansion.

Phenotypic and molecular characterization of 942 carbapenem-resistant Enterobacteriaceae (CRE) in southern Brazil *

Carbapenem-resistant Enterobacteriaceae (CRE) is a major international health problem, and its identification in developing countries is based exclusively on phenotypic methods. The aim of this study was to assess the sensitivity and related parameters of the modified Hodge test (MHT). The assessment was performed in a large number of isolates obtained from different hospitals in several cities of a south Brazilian state. Bacterial species were identified using an automated method. The MHT was performed according to the guidelines set by the CLSI. The gene blaKPC was amplified in order to confirmation CRE expression. The sensitivity, specificity, positive, and negative predictive values were calculated. A total of 942 isolates were submitted to the reference laboratory for confirmation; 143 showed a negative MHT (15.18%) result, while 784 were positive (83.23%), and 15 samples displayed an indeterminate MHT (1.59%) result. All samples expressed the KPC-2 enzyme. Sensitivity, specificity, positive, and negative predictive percentiles were 99%, 89%, 98%, and 99% respectively. We conclude that the modified Hodge test is a reliable test for the prediction of KPC-producing bacteria.

Validação do teste de inibição pelo ácido aminofenilborônico para triagem de Klebsiella pneumoniae carbapenemases (KPC)

INTRODUCTION: The production of Klebsiella pneumoniae carbapenemases enzymes (KPC) has become an important and worrisome resistance mechanism. Furthermore, tests that combine high sensitivity and high specificity for the detection of these enzymes are scarce. OBJECTIVE: To validate the inhibition test by 3-aminophenyl boronic acid as a phenotypic screening method for KPC-producing strains by comparing the results with confirmatory polymerase chain reaction testing (PCR). METHODS: We evaluated the use of 3-aminophenyl boronic acid applied on disks with imipenem, meropenem and ertapenem antibiotics. 36 strains were positive and 12 were negative, all confirmed by PCR. Three different concentrations of boronic acid were also tested: 300, 400 and 600 µg. RESULTS: Among the positive strains, the results were more accurate with the addition of the compound to the ertapenem disk, presenting 100 % specificity and 50% sensitivity. CONCLUSION: Further studies are required, mainly regarding the standardization of the technique and materials, since the method seems to be promising as to the screening of KPC strains.