A correlation study between virulence factors and multidrug resistance among clinical isolates of Proteus mirabilis.

Treatment of Proteus mirabilis infections is a challenge due to the high abundance of virulence factors and the high intrinsic resistance to antimicrobials. Multidrug resistance (MDR) and extensive drug resistance (XDR) further challenge the control of P. mirabilis infection. This study aimed to investigate the correlation between virulence determinants and multidrug resistance in 100 clinical isolates of P. mirabilis collected in Alexandria from December 2019 to June 2021. Susceptibility to antimicrobials was tested by the Kirby Bauer method. Detection of swarming, urease, protease, hemolysin, and biofilm formation was performed phenotypically and by PCR amplification of zapA, flaA, ureC, mrpA, atfA, ucaA, hpmA, and luxS. MDR and XDR were detected in 34% and 5%, respectively. All isolates were positive for motility, swarming, urease, and protease production. Ninety percent were positive for hemolysin production, while 73% formed biofilm. All isolates possessed the ureC and zapA genes. The luxS, flaA, ucaA, hpmA, mrpA, and atfA genes were detected in 99%, 98%, 96% 90%, 89%, and 84%, respectively. The presence of a single biofilm-related gene was statistically correlated with non-biofilm production (P= 0.018). It was concluded that P. mirabilis isolates from catheterized-urine samples were significantly associated with biofilm formation. MDR and virulence were not statistically correlated. A significant positive correlation was detected between some virulence genes in P. mirabilis. Non-MDR isolates of P. mirabilis had a high abundance of virulence factors with no statistically significant difference from MDR. Most of the MDR and all XDR isolates could produce biofilm.

Characterisation of plasmid-mediated rmtB-1 in Enterobacteriaceae clinical isolates from São Paulo, Brazil

OBJECTIVES The emergence of 16S rRNA methyltranferases (16 RMTAses) has jeopardised the clinical use of aminoglycosides. RmtB is one of the most frequently reported in Gram-negatives worldwide. In this study, we aimed to estimate the frequency of 16S RMTAses encoding genes in Enterobacteriaceae isolated in a three-month period from a tertiary Brazilian hospital. METHODS All Gram-negatives classified as resistant to amikacin, gentamicin, and tobramycin by agar screening were selected for analysis. The presence of 16SRMTases encoding genes was verified by polymerase chain reaction (PCR). Antimicrobial susceptible profile was determined by broth microdilution. The genetic relationship among these isolates was accessed by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Selected RmtB-producing isolates were characterised by whole genome sequencing (WGS) analysis. RESULTS Twenty-two of 1,052 (2.1%) Enterobacteriaceae were detected as producers of RmtB-1 [Klebsiella pneumoniae (n = 21) and Proteus mirabilis (n = 1)]. blaKPC-2 was identified among 20 RmtB-1-producing K. pneumoniae isolates that exhibited an identical PFGE and MLST (ST258) patterns. Two K. pneumoniae isolates, the A64216 (not harboring bla KPC-2), A64477 (harboring bla KPC-2) and one P. mirabilis isolate (A64421) were selected for WGS. rmtB-1 and bla KPC-2 genes were carried by distinct plasmids. While a plasmid belonging to the IncFIIk group harbored rmtB-1 in K. pneumoniae, this gene was carried by a non-typable plasmid in P. mirabilis. In the three analysed plasmids, rmtB-1 was inserted on a transposon, downstream a Tn2. CONCLUSION Our findings suggested that the rmtB-1 was harbored by plasmids distinct from those previously reported in Bolivia and China. It suggests that multiple mobilization events might have occurred in South America.

Detecção de Proteus mirabilis nas fezes de camundongos spf / /Detection of Proteus mirabilis in specifc pathogen free mice feces

O presente estudo teve como objetivo apresentar os resultados de pesquisa de positividade do microorganismo Proteus mirabilis em camundongos das linhagens C57BL/6, BALB/c e BALB/c Nude, originários do setor de criação de camundongos livres de patógenos específicos (SPF) do Centro de Bioterismo da Faculdade de Medicina da USP e relatar a importância do isolamento deste microorganismo em colônias de animais. Para tanto, amostras de fezes de 71 camundongos da linhagem C57BL/6, 48 camundongos da linhagem BALB/c e 26 camundongos da linhagem BALB/c Nude, foram semeadas em meios específicos para bactérias gram negativas e diagnosticado no Enterokit B da Probac do Brasil. Nossos resultados mostraram que, as linhagens de camundongos C57BL/6, BALB/c e BALB/c Nude apresentaram P.mirabilis nas fezes, nas porcentagens de 80,3%, 62,5% e 73,1% respectivamente, sendo inadequadas para utilização em protocolos experimentais das áreas de radiobiologia, imunologia, oncologia e cirurgias experimentais invasivas, por interferirem potencialmente nos resultados destas áreas. CEUA nº 251/11.

This study aimed to present the positive results of Proteus mirabilis research from strains inbred mice C57BL/6, BALB/c and BALB/c Nude, originating from the sector of Specific Pathogen Free (SPF) mice - Animal Facilities of Faculdade de Medicina (USP – University of São Paulo) and report the importance of isolation of this microorganism in colonies of animals. For this, stool samples from: 71 C57BL/6, 48 BALB/c and 26 BALB /c Nude inbred mice, were inoculated in cultural bacteria specific media and diagnosed in the B Enterokit Probac-Brasil. Our results showed that the strains of C57BL/6, BALB/c and BALB/c Nude presented P.mirabilis in stool, percentages of 80.3%, 62.5% and 73.1% respectively, being unsuitable for use in experimental protocols in the fields of radiobiology, immunology, oncology, and experimental invasive surgeries by interfering mainly on the results of these areas. CEUA No. 251/11.

Detecção de Proteus mirabilis nas fezes de camundongos spf / /Detection of Proteus mirabilis in specifc pathogen free mice feces

O presente estudo teve como objetivo apresentar os resultados de pesquisa de positividade do microorganismo Proteus mirabilis em camundongos das linhagens C57BL/6, BALB/c e BALB/c Nude, originários do setor de criação de camundongos livres de patógenos específicos (SPF) do Centro de Bioterismo da Faculdade de Medicina da USP e relatar a importância do isolamento deste microorganismo em colônias de animais. Para tanto, amostras de fezes de 71 camundongos da linhagem C57BL/6, 48 camundongos da linhagem BALB/c e 26 camundongos da linhagem BALB/c Nude, foram semeadas em meios específicos para bactérias gram negativas e diagnosticado no Enterokit B da Probac do Brasil. Nossos resultados mostraram que, as linhagens de camundongos C57BL/6, BALB/c e BALB/c Nude apresentaram P.mirabilis nas fezes, nas porcentagens de 80,3%, 62,5% e 73,1% respectivamente, sendo inadequadas para utilização em protocolos experimentais das áreas de radiobiologia, imunologia, oncologia e cirurgias experimentais invasivas, por interferirem potencialmente nos resultados destas áreas. CEUA nº 251/11.(AU)

This study aimed to present the positive results of Proteus mirabilis research from strains inbred mice C57BL/6, BALB/c and BALB/c Nude, originating from the sector of Specific Pathogen Free (SPF) mice - Animal Facilities of Faculdade de Medicina (USP University of São Paulo) and report the importance of isolation of this microorganism in colonies of animals. For this, stool samples from: 71 C57BL/6, 48 BALB/c and 26 BALB /c Nude inbred mice, were inoculated in cultural bacteria specific media and diagnosed in the B Enterokit Probac-Brasil. Our results showed that the strains of C57BL/6, BALB/c and BALB/c Nude presented P.mirabilis in stool, percentages of 80.3%, 62.5% and 73.1% respectively, being unsuitable for use in experimental protocols in the fields of radiobiology, immunology, oncology, and experimental invasive surgeries by interfering mainly on the results of these areas. CEUA No. 251/11.(AU)