Características y evolución clínica de las bacteriemias por Klebsiella pneumoniae productora de carbapenemasa tipo OXA-48 en un hospital de tercer nivel / Clinical features and outcomes of bacteraemia due to OXA-48-like carbapenemase-producing Klebsiella pneumoniae in a tertiary hospital

INTRODUCCIÓN: El manejo de las bacteriemias por Klebsiella pneumoniae productora de carbapenemasa del tipo OXA-48 (KPOXA-48) es complicado por las escasas opciones terapéuticas y la elevada mortalidad. El objetivo del estudio fue describir las características clínicas de bacteriemia por KPOXA-48 entre octubre de 2013 y diciembre de 2016. MATERIAL Y MÉTODOS: Se recogieron retrospectivamente de las historias clínicas las variables para analizar. La producción de carbapenemasas se confirmó por métodos fenotípicos y moleculares. RESULTADOS: Se incluyeron 38 pacientes con bacteriemia, mayoritariamente de origen nosocomial (n = 31). Un alto porcentaje de las bacteriemias (n = 26) fueron secundarias, principalmente de origen urinario (n = 11). Todos los aislamientos eran multirresistentes con producción de la beta-lactamasa de espectro extendido CTX-M-15 y carbapenemasa del tipo OXA-48. La mortalidad bruta con antibioterapia dirigida adecuada fue del 0% y la inadecuada del 55% (p = 0,0015). CONCLUSIONES: Se pone de manifiesto la importancia de identificar este mecanismo de resistencia, los factores del paciente, el tipo de bacteriemia y la adecuación de la estrategia terapéutica en la evolución clínica

INTRODUCTION: Community-acquired Staphylococcus aureus (SA) bacteraemia is a common cause of hospitalisation in children. The occurrence of secondary foci (SF) of SA infection is associated with higher morbidity and mortality. OBJECTIVES: To identify risk factors for SF of infection in children with community-acquired SA bacteraemia. MATERIAL AND METHODS: Prospective cohort. All children aged from 30 days to 16 years admitted to a paediatric referral hospital between January 2010 and December 2016 for community-acquired infections, with SA isolated in blood cultures, were included. Microbiological, demographic and clinical characteristics were compared, with or without SF infection after 72 hours of hospitalisation. RESULTS: A total of 283 patients were included, 65% male (n = 184), with a median age of 60 months (IQR: 30-132). Seventeen per cent (n = 48) had at least one underlying disease and 97% (n = 275) had some clinical focus of infection, the most common being: osteoarticular 55% (n = 156) and soft tissue abscesses 27% (n = 79). A total of 65% (n = 185) were resistant to methicillin. A SF of infection was found in 16% of patients (n = 44). The SF identified were pneumonia 73% (n=32), osteoarticular 11% (n = 5), soft tissue 11% (n = 5) and central nervous system 5% (n=2). In the multivariate analysis, the persistence of positive blood cultures after the fifth day (OR: 2.40, 95%CI: 1.07-5.37, P < 0.001) and sepsis (OR: 17.23, 95%CI 5.21-56.9, P < 0.001) were predictors of SF. There was no association with methicillin sensitivity. CONCLUSIONS: In this cohort, methicillin-resistant SA infections predominated. The occurrence of SF of infection was associated with the persistence of bacteraemia after the fifth day and sepsis on admission

Molecular Characterization of Markers Associated With Antimicrobial Resistance in Neisseria gonorrhoeae Identified From Residual Clinical Samples.

BACKGROUND: The emergence and spread of antimicrobial-resistant (AMR) Neisseria gonorrhoeae (NG) is a major public health concern. In the era of nucleic acid amplifications tests, rapid and accurate molecular approaches are needed to help increase surveillance, guide antimicrobial stewardship, and prevent outbreaks. METHODS: Residual urethral swabs, collected prospectively in the Baltimore City Health Department during a 6-month period, were analyzed by real-time polymerase chain reaction assays for NG DNA and AMR determinants to fluoroquinolones, penicillin, and extended-spectrum cephalosporins. RESULTS: N. gonorrhoeae DNA was detected in 34.8% (73/210) of samples, including 67.3% (68/101) of the swabs that had been previously identified as NG positive by culture. Markers associated with decreased susceptibility to fluoroquinolones were detected in 22.4% of the polymerase chain reaction NG-positive samples. The rate of penicillinase-producing NG was very low (1.6%), and no markers associated with decreased susceptibility to extended-spectrum cephalosporins were detected in this cohort of men using the AMR assays herein described. CONCLUSIONS: Detection of molecular markers associated with AMR in NG can be performed directly from residual clinical samples, although the recovery rate of adequate DNA for molecular testing from these samples can be suboptimal. A high number of samples with mutations associated with decreased susceptibility to fluoroquinolones were identified.

Molecular analyses of TEM genes and their corresponding penicillinase-producing Neisseria gonorrhoeae isolates in Bangkok, Thailand.

Neisseria gonorrhoeae is a major public health problem globally, especially because the bacterium has developed resistance to most antimicrobials introduced for first-line treatment of gonorrhea. In the present study, 96 N. gonorrhoeae isolates with high-level resistance to penicillin from 121 clinical isolates in Thailand were examined to investigate changes related to their plasmid-mediated penicillin resistance and their molecular epidemiological relationships. A ß-lactamase (TEM) gene variant, bla(TEM-135), that may be a precursor in the transitional stage of a traditional bla(TEM-1) gene into an extended-spectrum ß-lactamase (ESBL), possibly causing high resistance to all extended-spectrum cephalosporins in N. gonorrhoeae, was identified. Clonal analysis using multilocus sequence typing (MLST) and N. gonorrhoeae multiantigen sequence typing (NG-MAST) revealed the existence of a sexual network among patients from Japan and Thailand. Molecular analysis of the bla(TEM-135) gene showed that the emergence of this allele might not be a rare genetic event and that the allele has evolved in different plasmid backgrounds, which results possibly indicate that it is selected due to antimicrobial pressure. The presence of the bla(TEM-135) allele in the penicillinase-producing N. gonorrhoeae population may call for monitoring for the possible emergence of ESBL-producing N. gonorrhoeae in the future. This study identified a bla(TEM) variant (bla(TEM-135)) that is a possible intermediate precursor for an ESBL, which warrants international awareness.

[Penicillinase production by Neisseria gonorrhoeae strains isolated from the patients of Dermatology and Wenerology Clinic, Warsaw Medical University in 2006 - 2009]. / Wytwarzanie penicylinazy przez szczepy Neisseria gonorrhoeae izolowane od pacjentów kliniki dermatologii i wenerologii WUM w latach 2006-2009.

In recent years the resistance of Neisseria gonorrhoeae to antibiotics is increasing in many countries. The aim of the study was to investigate penicillinase production by Neisseria gonorrhoeae strains isolated from the patients of Clinic of Dermatology and Wenerology WUM in a period between 2006 - 2009. We cultured the bacteria on Roiron medium and we used the iodometric test or BBL Cefinase discs to detect penicillinase. The enzyme was produced by 1,1% of 183, 0,9% of 111, 1,1% of 94 and 0% of 91 of investigated strains, respectively in 2006, 2007, 2008 and 2009 year - on average by 0,8%. This is the lowest result in Europe and one of the lowest in the world.

Enhancing gonococcal antimicrobial resistance surveillance: a real-time PCR assay for detection of penicillinase-producing Neisseria gonorrhoeae by use of noncultured clinical samples.

With increasing concerns regarding diminishing treatment options for gonorrhea, maintaining the efficacy of currently used treatments and ensuring optimal Neisseria gonorrhoeae antimicrobial resistance surveillance are of the utmost importance. Penicillin is still used to treat gonorrhea in some parts of the world. In this study, we developed and validated a real-time PCR assay for the detection of penicillinase-producing N. gonorrhoeae (PPNG) in noncultured clinical samples with the aim of enhancing penicillin resistance surveillance. The assay (PPNG-PCR2) was designed to be an indirect marker of penicillinase activity, by targeting a region of sequence predicted to be conserved across all N. gonorrhoeae plasmid types harboring the beta-lactamase gene while not specifically targeting the actual beta-lactamase-encoding sequence. The assay was evaluated by using a total of 118 N. gonorrhoeae clinical isolates and 1,194 clinical specimens, including 239 N. gonorrhoeae-positive clinical samples from which N. gonorrhoeae cells were isolated and for which phenotypic penicillinase results are available. Overall, the PPNG-PCR2 assay provided 100% sensitivity and 98.7% specificity compared to bacterial culture results for the detection of PPNG in clinical specimens. PPNG-PCR2 false-positive results, presumably due to cross-reactions with unrelated bacterial species, were observed for up to 1.3% of clinical samples but could be distinguished on the basis of high cycle threshold values. In tandem with phenotypic surveillance, the PPNG-PCR2 assay has the potential to provide enhanced epidemiological surveillance of N. gonorrhoeae penicillin resistance and is of particular relevance to regions where penicillin is still used to treat gonorrhea.

Antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in 2004-2006 in Bangui, Central African Republic; Yaoundé, Cameroon; Antananarivo, Madagascar; and Ho Chi Minh Ville and Nha Trang, Vietnam.

GOAL: To investigate the in vitro antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in 2004 and 2005 in Bangui, Central African Republic; Yaoundé, Cameroon; Antananarivo, Madagascar; and Ho Chi Minh Ville and Nha Trang, Vietnam. STUDY DESIGN: Antimicrobial susceptibility testing was performed by both disk diffusion and agar dilution methods according to Clinical and Laboratory Standards Institute (CLSI) recommendations. Minimum inhibitory concentrations (MICs) to 5 antimicrobials (penicillin G, ceftriaxone, ciprofloxacin, spectinomycin, and tetracycline) were determined when feasible. Penicillinase-producing N. gonorrhoeae (PPNG) was analyzed by the paper acidometric method (nitrocefin test). RESULTS: Thirty N. gonorrhoeae isolates from Bangui could be studied, 79 from Yaoundé, 126 from Antananarivo, 56 from Nha Trang, and 126 from Ho Chi Minh Ville in 2004 and 2005. Unfortunately, because of problems of electricity supply, no strains could be recovered for the determination of MICs in Yaoundé, and only 68 strains could be tested in Antananarivo and 121 in Ho Chi Minh Ville. Patterns of resistance were similar in Antananarivo, Bangui, and Yaoundé but different from those observed in Vietnam. Ciprofloxacin was highly effective in Africa, but nearly all strains in Vietnam were resistant to this drug. Overall, ceftriaxon and spectinomycin were the best antibiotics, with one strain resistant to spectinomycin in Antananrivo and one strain resistant to ceftriaxon in Ho Chi Minh Ville. CONCLUSIONS: Ciprofloxacin remains highly efficient in Madagascar and Central Africa, ceftriaxone and spectinomycin should be used as the first-line antimicrobial agents in treating gonorrhea in Vietnam.

Analysis of the beta-lactam resistance phenotypes of Escherichia coli. An 8-year survey conducted in Greece.

There have been few studies, outside of France, on the resistance of Escherichi coli to beta-lactams by means of resistance phenotypes. In the present 8-year study from a tertiary Greek hospital, a statistically significant decrease in wild-type strains was noted, with a parallel increase in strains producing penicillinase. Of the total 6,089 isolates analyzed, 62.47% had no acquired resistance mechanisms while 35.70% produced penicillinase, 0.61% cefalosporinase and 0.94% extended-spectrum beta-lactamase. No overexpression of chromosomal cephalosporinase or synthesis of inhibitor-resistant enzymes was found. A shift in the pattern of penicillinase production was noted as, in the early years of the study, intermediate- and high-level penicillinase predominated whereas, in later years, low-level penicillinase prevailed.

The arl locus positively regulates Staphylococcus aureus type 5 capsule via an mgrA-dependent pathway.

Most clinical Staphylococcus aureus strains produce either type 5 or type 8 capsular polysaccharides. The production of these capsules is influenced by various environmental factors. To study the regulation of capsule, Tn551 transposon mutagenesis and transcriptional reporter gene fusion were employed to identify several putative regulatory loci that influenced capsule gene expression. One of these, the arl locus, was chosen for further analysis. Tn551 was found to insert within the coding region (near the translational start site of the arlR gene). ArlR, along with ArlS, forms a two-component system that has been previously shown to affect autolysis and production of several secreted proteins. Phenotypic analyses of the arlR-specific mutant and gene fusion analyses showed that arlR activated capsule production at the transcriptional level. However, gel mobility shift assays did not support activation of the capsule genes by direct ArlR binding to the primary cap5 promoter region upstream of the operon. In contrast, it was found that arl activated mgrA, an activator for capsule production, whereas mgrA did not have a significant effect on arlR. Genetic studies supported the notion that arlR functions upstream of mgrA with respect to the regulation of capsule production, although gene fusion studies indicated that arl could also regulate capsule independently from mgrA. Collectively, the results suggest that arl positively regulates capsule production at the transcriptional level primarily through an mgrA-dependent pathway.

Study of five penicillinase producing Neisseria gonorrhoeae isolated in Italy.

Five penicillinase producing Neisseria gonorrhoeae (PPNG) were isolated from urethral specimens of men admitted to the "Santa Chiara" Hospital (Trento, Italy). All strains proved to be resistant to penicillin and ampicillin, and sensitive to cefuroxime, erythromycin, tetracycline, spectinomycin, nalidixic acid and ciprofloxacin. PPNG plasmid profiles showed that four of the isolates carried the 3.2 MDa "Africa" plasmid and one the 4.5 MDa "Asia" plasmid, the two well-known phenotypes reported in the USA and Europe as well as in Asian and African countries. Membrane matings were performed using N. gonorrhoeae carrying the 24.5 MDa conjugative plasmid as donors and E. coli K12 J 53 as recipient. The transfer of beta-lactamic antibiotic resistance was supported by the presence of 4.5 or 3.2 MDa plasmid bands and by beta-lactamase production in the transconjugants. Restriction analysis of Asian and African plasmids is reported.

Amoxicillin-clavulanate therapy increases childhood nasal colonization by methicillin-susceptible Staphylococcus aureus strains producing high levels of penicillinase.

We examined factors associated with penicillinase production by nasal carriage Staphylococcus aureus strains in 648 children aged 3 to 6 years attending 20 randomly sampled playschools. The children were prospectively monitored for drug use and medical events for 6 months and were then screened for S. aureus carriage. Isolates were tested for their susceptibility to penicillin G and methicillin, and penicillinase production by methicillin-susceptible, penicillin-resistant strains was quantified. S. aureus was isolated from 166 children (25.6%). Exposure to amoxicillin-clavulanate during the previous 3 months was associated with higher penicillinase production by penicillin-resistant, methicillin-susceptible strains (odds ratio, 3.6; P = 0.03). These results suggest that use of the amoxicillin-clavulanate combination could induce a herd selection process of S. aureus strains producing higher levels of penicillinase.

Gonorrhoea in young heterosexuals attending urban STD clinics in Britain: a cross-sectional survey.

Young people in the UK bear the brunt of sexually transmitted infections, in particular of gonorrhoea. We aimed to assess whether young people with gonorrhoea (under 21 years) attending sexual health clinics differed from older individuals with gonorrhoea in their behavioural and clinical characteristics and management outcomes. The results of this cross-sectional study suggest that young people were more likely to be female (66.2% vs 34.1%), have concurrent infection with Chlamydia trachomatis (55.4% vs 30.2%) and a history of recent gonococcal infection (81.3% vs 35.5%) if they ever had gonorrhoea. Young women were more likely to experience treatment delay and not to attend for follow-up than older women. Resistance to ciprofloxacin was high in both age groups but the prevalence of penicillinase-producing Neisseria gonorrhoeae was higher in older patients (11.5% vs 1.3%). Different management protocols for young and older patients with gonorrhoea may need to be considered.

The changing epidemiology of Staphylococcus aureus?

Strains of methicillin-resistant Staphylococcus aureus (MRSA), which had been largely confined to hospitals and long-term care facilities, are emerging in the community. The changing epidemiology of MRSA bears striking similarity to the emergence of penicillinase-mediated resistance in S. aureus decades ago. Even though the origin (hospital or the community) of the emerging MRSA strains is not known, the prevalence of these strains in the community seems likely to increase substantially.

[Correlation between sensitivity to fosfomycin and the presence of penicillinase PSE-1 in Pseudomonas aeruginosa]. / Corrélation entre la sensibilité à la fosfomycine et la présence d'une pénicillinase PSE-1 chez Pseudomonas aeruginosa.

A prospective survey was carried out during three three-weeks periods in May, October 1997 and October 1998 in 13 teaching hospitals. All non-repetitive isolates of P. aeruginosa collected were subject to serotypage and determination of the inhibiting minimal concentrations for ticarcillin, piperacillin, piperacillin + tazobactam, ceftazidime, imipenem, amikacin, ciprofloxacin and fosfomycin. Identification of the betalactamases and quantification of the cephalosporinase were done for the strains intermediate or resistant to ticarcillin. The most frequent serotypes were O: 6 (17%), O: 11 (13%), O: 1 (10%) and O: 12 (9%). Serotype O: 12 was the least susceptible to antibiotics except for fosfomycin. Whatever the serotype, 76% of P. aeruginosa strains with bla PSE-1 are susceptible to fosfomycin, when only 29.8% of non bla PSE-1 producing strains were susceptible to this antibiotic. Integron encoding bla PSE-1 could be implicated in susceptibility to fosfomycin of P. aeruginosa strains. The associations fosfomycin + imipenem or fosfomycin + ceftazidime could be proposed in case of infections due to P. aeruginosa O: 12.

New Staphylococcus aureus incompatibility group 1 plasmids encoding penicillinase production and resistance to different antibacterial agents.

Eleven Staphylococcus aureus plasmids encoding penicillinase production and resistance to different antibacterial agents were transferred to laboratory recipient strains in mixed-culture transfer and transduction experiments and characterized by restriction endonuclease analysis and incompatibility. The plasmids were differentiated into four types (types A-D) on the basis of their resistance phenotypes and restriction endonuclease patterns. One type encoded resistance to cadmium and arsenate. The second type encoded resistance to cadmium, mercuric compounds and nucleic acid-binding compounds. The third type encoded resistance to cadmium, kanamycin, neomycin and streptomycin while the fourth type encoded resistance to kanamycin, neomycin and ethidium bromide. Plasmids within the same class were structurally related or similar and were different from those in the other classes. Three plasmids, pWBG626, pWBG628, and pWBG663, representing three of the four plasmid types, belonged to incompatibility group 1. These new plasmids add to the number of known incompatibility group 1 plasmids and have resistance phenotypes which should be useful for studying incompatibility of new S. aureus plasmids.

Non-penicillinase producing Neisseria gonnorhoeae: are they still in existence in Ibadan, Nigeria?

In an attempt to evaluate the current prevalence rate of penicillinase producing Neisseria gonorrhoeae (PPNG) and whether non-PPNG strains are still in existence in Ibadan, Nigeria, all isolates of Neisseria gonorrhoeae from patients that attended our clinic between January and December 1997 were studied. Of the 155 patients that had gonococcal infections, 118 were male (76.1%) and 37 (23.9%) were female with 31 (83.8%) being the partners of infected men. Sixty-four (54.2%) of the male and 19 (51.4%) of the female were aged between 20 and29 years while 21.2% of the male and 16.2% of the female were in the age of 40 and above. The sex difference is not statistically significant (chi2=1.47,P=-0.69). The present study revealed that non-PPNG strains have reduced considerably to 5.4% from 100% in 1977. This has posed a great threat to the usefulness of penicillin and ampicillin as the drugs of choice in gonococcal therapy in Nigeria.

Antibiotic resistant N. gonorrhoeae in Trinidad and Tobago.

We tested the susceptibility patterns of 128 N. gonorrhoeae isolates to six antimicrobials; penicillin, tetracycline, spectinomycin, ceftriaxone, ciprofloxacin and azithromycin, and examined whether certain demographic or behavioral factors related to antibiotic use increased the likelihood of infection by a resistant strain. There was a low rate of resistance to penicillin; penicillinase-producing and chromosomal-mediated penicillin resistant gonorrhea were estimated to be 0.8%. A much higher proportion of isolates were resistant to tetracycline (up to 15%). All isolates were sensitive to spectinomycin, ciprofloxacin and ceftriaxone. However, less than 2% of isolates displayed intermediate resistance to both ciprofloxacin and ceftriaxone, and 9% exhibited intermediate resistance to spectinomycin. Patients who had obtained medication before attending the clinic and had taken all of the medication were more likely (p = 0.03) to be infected with a resistant strain of gonococcus. Also, patients who were asked by a clinic doctor to return for a test of cure during an earlier clinic visit, but who did not return were more likely to be infected with a resistant organism (p = 0.006) compared to those who returned at the doctor's request. These findings have important implications for antibiotic use and educational programs in Trinidad and Tobago.

[Bacterial growth delay in E. coli: demonstration and evaluation of the beta-lactamase post-inhibitor effect on 6 strains with different resistance phenotypes]. / Retard de recroissance bactérienne chez E. coli: mise en évidence et évaluation d'un effet postinhibiteur de beta-lactamases sur six souches de phénotypes de résistance différents.

Six E. coli, whose phenotypes of resistance were different, were tested in vitro in order to evaluate a regrowth delay, the post beta-lactamases inhibitor effect (PLIE). This PLIE was investigated after a brief incubation in contact with clavulanic acid (CA) alone or associated with amoxicillin (AMX). After removal of the drugs used during the pre-exposure phase, the bacteria were incubated with AMX at different concentrations. The PLIE was shown not to be in association with any other regrowth delay (post-antibiotic effect or effect inherent to the technical procedures used). A PLIE was evaluated on the five intermediary or high-level beta-lactamases-producing strains. Generally, the duration of the PLIE was prolonged after the CA alone pre-exposure phase and could reach values up to 22 hours. The concentrations of AMX added in cultures previously exposed to sufficient CA concentrations were related to an extended PLIE.

A multiplex polymerase chain reaction to differentiate beta-lactamase plasmids of neisseria gonorrhoeae.

In penicillinase-producing Neisseria gonorrhoeae (PPNG), resistance to penicillin may be mediated by one of several related plasmids of different sizes. These include the Asian, African and Rio/Toronto plasmids. Identification of these plasmids provides useful epidemiological information, but has necessitated plasmid purification and gel analysis. We have developed a rapid, simple multiplex polymerase chain reaction (PCR) which discriminates between the beta-lactamase resistance plasmids that are frequently found in strains of N. gonorrhoeae. Amplicons of 1191, 958 and 650 bp were produced from strains containing the African, Asian and Rio/Toronto plasmids, respectively, whilst no products resulted from non-PPNG strains harbouring the cryptic, conjugative or tetracycline resistance plasmids. PCR analysis of 123 strains of PPNG identified 60 strains with African, 16 strains with Asian and 47 strains with Rio/Toronto plasmids and showed complete agreement with the standard plasmid analysis.