Outbreak caused by a multi-resistant Klebsiella pneumoniae strain of new sequence type ST341 carrying new genetic environments of aac(6′)-Ib-cr and qnrS1 genes in a neonatal intensive care unit in Spain

An outbreak due to a Klebsiella pneumoniae clone occurred in a neonatal intensive care unit of a Spanish Hospital in which three newborns were infected (all with gestational age ≤29 weeks; two of them died) and seven were colonized (gestational age >32 weeks; none died). One K. pneumoniae strain per patient was further characterized. The 10 strains showed an indistinguishable pulsed-field-gel-electrophoresis pattern, were typed in the phylogenetic group KpI and were ascribed into a new sequence type registered as ST341. All 10 strains presented the same multiple-antibiotic-resistant phenotype, showed extended-spectrum-beta-lactamase production, and harbored the bla_CTX-M-15, bla_SHV-11, bla_OXA-1,aac(6′)-Ib-cr, qnrS1, aac(3)-II, aph(3′)-Ia and aadA5 resistance genes. No class 1 or class 2 integrons were detected. The bla_CTX-M-15 gene presented the following genetic environment: ISEcp1-bla_CTX-M-15-orf477. These strains contained two copies of the aac(6′)-Ib-cr gene included in the following new genetic environments: aac(3)-II-IS26-aac(6′)-Ib-cr-bla_OXA-1 and aac(3)-II-IS26-ΔcatB3-bla_OXA-1-aac(6′)-Ib-cr (registered at GenBank with accession numbers GQ438247 and GQ438248, respectively). The genetic environment of the qnrS1 gene (IS26-ΔISEcl2-qnrS1) (GenBank accession number GQ438249) was also not described previously. The aac(6′)-Ib-cr, qnrS1, bla_CTX-M-15, aac(3)-II, and bla_OXA-1 genes, located in a plasmid of 33.5 kb, could be transferred to Escherichia coli by transformation.     

Membrane proteomes of Pseudomonas aeruginosa and Acinetobacter baumannii

Acinetobacter baumannii and Pseudomonas aeruginosa are known for their intrinsic resistance to antibiotics. Between mechanisms involved in this resistance, diminished expression of outer membrane proteins and up-regulation of efflux pumps play an important role. The characterization of membrane proteins is consequently necessary because of their importance in the antibiotic resistance but also in virulence. This review presents proteomic investigations aiming to describe the protein content of the membranes of these two bacterial species.     

Clonality of clinical methicillin-resistant Staphylococcus epidermidis isolates in a neonatal intensive care unit

OBJECTIVE: Study of the clonality of methicillin-resistant Staphylococcus epidermidis responsible of epidemic infections in a neonatal intensive care unit. PATIENTS AND METHODS: All S. epidermidis isolates (mecA+) were collected during the epidemic period (December 2003-September 2004) from different pathological products of newborns. Isolates were characterized by genotyping in pulsed-field gel electrophoresis and by electrophoretic profiles obtained by PCR-based analysis of inter-IS256 spacer polymorphisms. RESULTS: Twenty methicillin-resistant S. epidermidis isolates were collected from newborns during the epidemic period and represented 41.6% of the total isolates of S. epidermidis, which is the first Staphylococcus species isolated from the unit. These isolates were collected from blood cultures (80%), vascular catheters (5%), pus (10%), and intra-tracheal tube (5%). Six genotypic profiles were individualized: type A, type B, type C, type D, type E, and type F, with clear dominance of type A. Five different PCR patterns were found with poor correlation to genotypes defined by PFGE. CONCLUSION: Neonatal nosocomial outbreak of methicillin-resistant S. epidermidis was caused by multiple clones of this species with predominance of one epidemic and multiresistant clone. This clone may be transmitted between babies and was able to persist in the unit. PCR IS 256 proved to be less discriminative than PFGE for typing MRSE.     

Novel cassette array in a class 1 integron in clinical isolates of Acinetobacter baumannii from central Iran

Antibiotic resistance in Acinetobacter baumannii is a major problem in the hospital and outbreaks caused by this organism have been reported frequently. The present study aimed at determining the antibiotic susceptibility patterns, the prevalence of different classes of integrons and the characterization of integron class 1 gene cassettes in Iranian A. baumannii isolates. A total of 63 non-duplicate A. baumannii isolates were collected from clinical and environmental specimens in the Vali-Asr hospital in the central province of Iran (March to September, 2011). The antimicrobial susceptibility for 15 antibiotics which are used conventionally was determined by disk diffusion. The presence of different integron classes was investigated by PCR and the size of gene cassettes in class 1 integrons was then determined by PCR as well. Moreover, integron cassette arrays of isolates were delineated by RFLP and sequencing amplicons with different lengths. Of 63 isolates 62 (98.4%) carried a class 1 integron. The prevalence of IntI2 was 15.9% and the length of the amplicons ranged from 500 bp to 3 kb. Sequencing of integrons of class 1 revealed the presence of many resistance genes (aadA, aacA, aacC, dfrA, bla_GES and bla_IMP). We identified a completely new gene cassette which contained aacA7-qacF-aadA5-bla_IMP, this cassette has not been reported previously in A. baumannii.     

Emergence of VIM-4- and SHV-12-producing Enterobacter cloacae in a neonatal intensive care unit

In order to reveal colonization with multidrug-resistant bacteria early, routine screening is done on samples of all patients of the neonatal intensive care units at Semmelweis University, Hungary. Due to the extended-spectrum β-lactamase (ESBL) screening examinations, emergence of multidrug-resistant Enterobacter cloacae isolates was found with suspicion of clonal transmission, therefore active microbiological surveillance was initiated. The aim of our study was to characterize 60 E. cloacae isolates recovered in a 7-month period in 2010. MIC values of antibiotics were determined and ESBL and carbapenemase production was tested. Metallo-β-lactamase (MBL) genes, ESBL genes, and class-1 integrons were characterized, and the possible clonal relationship between isolates was investigated. The isolates showed increased MIC values for carbapenems and cephalosporins. All 60 E. cloacae strains recovered from 16 neonates proved to be VIM-4 MBL producers. Fifty-three strains were SHV-12 ESBL producers also. In all cases, the bla_VIM-4 gene was a part of class-1 integron, In238a. XbaI-macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) revealed identical patterns for the isolates. Our study supports the importance of active microbiological surveillance as well as molecular epidemiology at the NICUs as a part of infection control.     

Gangrene intestine caused by Ascaris lumbricoides; Report of 5 cases in children

Ascaris infestation in the gastrointestinal tract is well known in Asian countries. It can be asymptomatic or can present with symptoms of acute abdomen. Perforation and torsion with gangrene are its very rare fatal complications but an important cause of mortality in children.     

Characterization of biofilms formed by Candida parapsilosis, C. metapsilosis, and C. orthopsilosis

Infections due to Candida parapsilosis have been associated with the ability of this fungus to form biofilms on indwelling medical devices. Recently, C. parapsilosis isolates were reclassified into 3 genetically non-identical classes: C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Little information is available regarding the ability of these newly reclassified species to form biofilms on biomedical substrates. In this study, we characterized biofilm formation by 10 clinical isolates each of C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Biofilms were allowed to form on silicone elastomer discs to early (6 h) or mature (48 h) phases and quantified by tetrazolium (XTT) and dry weight assays. Surface topography and three-dimensional architecture of the biofilms were visualized using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), respectively. Metabolic activity assay revealed strain-dependent biofilm forming ability of the 3 species tested, while biomass determination revealed that all 3 species formed equivalent biofilms (P>0.05 for all comparisons). SEM analyses of representative isolates of these species showed biofilms with clusters of yeast cells adherent to the catheter surface. Additionally, confocal microscopy analyses showed the presence of cells embedded in biofilms ranging in thickness between 62 and 85 μm. These results demonstrate that similar to C. parapsilosis, the 2 newly identified Candida species (C. orthopsilosis and C. metapsilosis) were able to form biofilms.     

Stenotrophomonas maltophilia responsible for respiratory infections in neonatal intensive care unit: antibiotic susceptibility and molecular typing

Objective

The aim of this study was to investigate the molecular epidemiology of Stenotrophomonas maltophilia strains responsible for respiratory infection in a neonatal intensive care unit (NICU) in Tunis City, isolated during 22 months (December 2003–September 2005).

Materials and methods

Twelve strains of S. maltophilia isolated from tracheal aspirates of distinct infants and two environmental strains were tested for antibiotic susceptibility and genotyped by pulsed-field gel electrophoresis (PFGE) method.

Results

Unlike a large heterogeneity demonstrated by the antibiotyping method, PFGE identified two concomitant outbreaks consisting of nine, including an environmental strain (clone A), and four strains (clone B), respectively; a distinguishable strain was classified in a unique pattern (PFGE type C). The long-term dissemination of these strains is a characteristic feature of these outbreaks. Improvement of hygienic conditions attributed to a markedly decrease in their isolation frequencies. Concomitant outbreaks and long period persistence of S. maltophilia in NICU is an important finding of this study.

Conclusion

Identification of two clonal strains of S. maltophilia responsible of respiratory infection. Epidemic strains are hardly eradicated when colonization is established.     

Virulence attributes of Histophilus somni with a deletion mutation in the ibpA gene

Histophilus somni strain 2336 contains a large open reading frame of 12,285-bp length, ibpA, encoding the immunoglobulin binding protein (IbpA) which is associated with H. somni serum resistance. To elucidate other functions of the strain 2336 IbpA protein, an ibpA isogenic mutant, 2336.A1, was created by replacement of an 11.6-kb ibpA sequence with a kanamycin resistant gene cassette. Both the mutant strain 2336.A1 and the wild-type strain 2336 adhered at similar levels to bovine turbinate cells, bovine endometrial epithelial cells and bovine macrophage-like FBM-17 cells. However, a remarkable cytotoxic effect associated with disruption of actin filaments was observed in FBM-17 cells infected with strain 2336 but not with strain 2336.A1. Cytotoxicity was also noted with the wild type but not the mutant in assays with murine J774.1 macrophage cells and bovine primary monocytes. Inhibition of phagocytosis of microspheres was found in assays with murine J774.1 cells and bovine primary monocytes infected with strain 2336 but not with strain 2336.A1. These results indicate that H. somni IbpA protein inhibits phagocytic activity of macrophages and monocytes, probably by disruption of actin filament structure.     

Intestinal autophagy activity is essential for host defense against Salmonella typhimurium infection in Caenorhabditis elegans

Salmonella typhimurium infects both intestinal epithelial cells and macrophages. Autophagy is a lysosomal degradation pathway that is present in all eukaryotes. Autophagy has been reported to limit the Salmonella replication in Caenorhabditis elegans and in mammals. However, it is unknown whether intestinal autophagy activity plays a role in host defense against Salmonella infection in C. elegans. In this study, we inhibited the autophagy gene bec-1 in different C. elegans tissues and examined the survival of these animals following Salmonella infection. Here we show that inhibition of the bec-1 gene in the intestine but not in other tissues confers susceptibility to Salmonella infection, which is consistent with recent studies in mice showing that autophagy is involved in clearance of Salmonella in the intestinal epithelial cells. Therefore, the intestinal autophagy activity is essential for host defense against Salmonella infection from C. elegans to mice, perhaps also in humans.     

Mutational analysis of GIGYF2, ATP13A2 and GBA genes in Brazilian patients with early-onset Parkinson's disease

In the last decade, several genes have been linked to Parkinson's disease (PD), including GIGYF2, ATP13A2 and GBA. To explore whether mutations in these genes contribute to development of PD in the Brazilian population, we screened 110 patients with early-onset PD. No clearly pathogenic mutations were identified in ATP13A2 and GIGYF2. In contrast, we identified a significantly higher frequency of known pathogenic mutations in GBA gene among the PD cases (6/110 = 5.4%) when compared to the control group (0/155) (P = 0.0047). Our results strongly support an association between GBA gene mutations and an increased risk of PD. Mutations in GIGYF2 and ATP13A2 do not seem to represent a risk factor to the development of PD in the Brazilian population. Considering the scarcity of studies on GIGYF2, ATP13A2 and GBA mutation frequency in Latin American countries, we present significant data about the contribution of these genes to PD susceptibility.     

Comparative analysis of respiratory chain and oxidative phosphorylation in Leishmania tarentolae, Crithidia fasciculata, Phytomonas serpens and procyclic stage of Trypanosoma brucei

Trypanosomatids are unicellular parasites living in a wide range of host environments, which to large extent shaped their mitochondrial energy metabolism, resulting in quite large differences even among closely related flagellates. In a comparative manner, we analyzed the activities and composition of mitochondrial respiratory complexes in four species (Leishmania tarentolae, Crithidia fasciculata, Phytomonas serpens and Trypanosoma brucei), which represent the main model trypanosomatids. Moreover, we measured the activity of mitochondrial glycerol-3-phosphate dehydrogenase, the overall oxygen consumption and the mitochondrial membrane potential in each species. The comparative analysis suggests an inverse relationship between the activities of respiratory complexes I and II, as well as the overall activity of the canonical complexes and glycerol-3-phosphate dehydrogenase. Our comparative analysis shows that mitochondrial functions are highly variable in these versatile parasites     

Outbreak of OXA-48-producing Enterobacteriaceae in a neonatal intensive care unit in Western Sweden

European Journal of Clinical Microbiology & Infectious Diseases - In 2015, an outbreak caused by OXA-48-producing Enterobacteriaceae affected a neonatal intensive care unit at a Swedish...     

重症监护室2154例新生儿血电解质分析及临床意义

目的探讨重症监护室新生儿电解质紊乱的类型及发生率之间的关系,指导临床治疗.方法患儿入室后立即取桡动脉血0.1ml,采用美国i-STAT便携式血气分析仪测定血电解质,以后根据病情再复查血电解质.结果 2154例患儿共4073例次血电解质测定中,有1244例(57.75%)共1739例次伴不同类型的电解质紊乱,其中低钠血症368例,高钠血症7例,低钾血症273例,高钾血症79例,低钙血症388例,高钙血症215例,且与原发病有关.结论对危重新生儿血电解质进行动态监测,提高了诊断的准确性,极大地提高了抢救成功率.     

A single step multiplex PCR for identification of six diarrheagenic E. coli pathotypes and Salmonella

E. coli is generally a commensal but includes some highly pathogenic strains carrying additional genes in plasmids and/or the chromosome. Based on these genes the pathogenic strains are divided into pathotypes including enteropathogenic (EPEC), enterohemorrhagic (EHEC), enterotoxigenic (ETEC), enteroaggregative (EAEC), enteroinvasive (EIEC) and diffusely adherent (DAEC) E. coli. Here, previously developed multiplex PCR strategies for these strains were integrated into one single step multiplex that differentiates all these E. coli pathotypes, usually based on multiple characteristic PCR products. This multiplex PCR works reliably for colony PCR. Two additional markers were added: one to detect most Enterobacteriacea, which acts as a positive control for successful PCR, and one to distinguish Salmonella. The multiplex correctly classified a set of 45 reference strains by colony PCR and 71 (45 + 26) strains by in silico PCR. It was then used to interrogate 44 clinical strains from bovine hosts resulting in detection of EAEC and DAEC determinants.     

Outbreak of Streptococcus pyogenes emm type 58 in a high dependency unit of a level-1 trauma center of India

Background and Aims:

Group A Streptococcus (GAS) can cause illnesses ranging from self-limited to severe, life-threatening, invasive infections. The objective of the following study was to investigate a suspected Streptococcus pyogenes outbreak in a high dependency unit (HDU) of our trauma center.

Materials and Methods:

All the isolates of beta hemolytic Streptococci were identified by standard microbiological methods, Vitek 2 system and latex agglutination tests. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute. Exotoxin genes, including speA, speB, speC, speF, smeZ, ssa, speG, speH, speJ, speL, speM and speI were detected by polymerase chain reaction (PCR). The emm types of isolates of S. pyogenes were determined by sequencing the variable 5’ end of emm gene after amplification by PCR.

Results:

In a 28 bedded poly-trauma ward with a four bedded HDU three out of four patients developed S. pyogenes emm type 58 infection. The strain was macrolide and tetracycline resistant and produced the Streptococcal pyrogenic exotoxins speB, speC, speG, speF and smeZ. Surveillance sampling was done for investigation from patients, health-care workers and environmental samples.

Conclusion:

An outbreak of GAS infections was established caused by the uncommonly reported emm type 58. The outbreak was controlled by prompt treatment, intensive surveillance, feedback and training.