Antimicrobial Resistance Profiles of Pseudomonas aeruginosa in the Arabian Gulf Region Over a 12-Year Period (2010-2021).

OBJECTIVES: To evaluate literature from a 12-year period (2010-2021) on the antimicrobial resistance profile of Pseudomonas aeruginosa from the Arabian Gulf countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates). METHODS: An electronic literature search was conducted for articles on antimicrobial resistance in P. aeruginosa and associated phenotypes, covering the period of 1st January 2010 to 1st December 2021. RESULTS: Antimicrobial resistance in the Arabian Gulf was highest to meropenem (10.3-45.7%) and lowest to colistin (0.0-0.8%), among the agents tested. Annual data showed that ceftazidime resistance (Kuwait), piperacillin-tazobactam non-susceptibility (Qatar), and aztreonam, imipenem, and meropenem resistance (Saudi Arabia) increased by 12-17%. Multiple mechanisms of carbapenem resistance were identified and multiple clones were detected, including high-risk clones such as ST235. The most common carbapenemases detected were the VIM-type metallo-ß-lactamases. CONCLUSIONS: Among P. aeruginosa in the Arabian Gulf countries, resistance to meropenem was higher than to the other agents tested, and meropenem resistance increased in Saudi Arabia during the study period. Resistance to colistin, a classic antibiotic used to treat Pseudomonas spp. infections, remained low. The VIM-type ß-lactamase genes were dominant. We recommend local and regional antimicrobial resistance surveillance programs to detect the emergence of resistance genes and to monitor antimicrobial resistance trends in P. aeruginosa.

Discovery of the tigecycline resistance gene cluster tmexCD3-toprJ1 in Pasteurella multocida strains isolated from pigs in China.

Pasteurella multocida is a leading cause of respiratory disorders in pigs. However, the genotypes and antimicrobial resistance characteristics of P. multocida from pigs in China have not been reported frequently. In this study, we investigated 381 porcine strains of P. multocida collected in China between 2013 and 2022. These strains were assigned to capsular genotypes A (69.55%, n = 265), D (27.82%, n =106), and F (2.62%, n = 10); or lipopolysaccharide genotypes L1 (1.31%, n = 5), L3 (24.41%, n = 93), and L6 (74.28%, n = 283). Overall, P. multocida genotype A:L6 (46.46%) was the most-commonly identified type, followed by D:L6 (27.82%), A:L3 (21.78%), F:L3 (2.62%), and A:L1 (1.31%). Antimicrobial susceptibility testing showed that a relatively high proportion of strains were resistant to tetracycline (66.67%, n = 254), and florfenicol (35.17%, n = 134), while a small proportion of strains showed resistance phenotypes to enrofloxacin (10.76%, n = 41), ampicillin (8.40%, n = 32), tilmicosin (7.09%, n = 27), and ceftiofur (2.89%, n = 11). Notably, Illumina short-read and Nanopore long-read sequencing identified a chromosome-borne tigecycline-resistance gene cluster tmexCD3-toprJ1 in P. multocida. The structure of this cluster was highly similar to the respective structures found in several members of Proteus or Pseudomonas. It is assumed that the current study identified the tmexCD3-toprJ1 cluster for the first time in P. multocida.

Investigating volatile semiochemical production from Bos taurus and Bos indicus as a novel phenotype for breeding host resistance to ixodid ticks.

Ticks and tick-borne diseases cause significant loss in livestock production with about 80% world's cattle at risk. The cost of chemical control is high and there is an ever-increasing tick resistance to chemical acaricides. Genetic selection as alternative long-term control strategy is constrained by laborious phenotyping using tick counts or scores. This study explored the use of host volatile semiochemicals that may be attractants or repellents to ticks as a phenotype for new tick resistance, with potential to be used as a proxy in selection programmes. Approximately 100 young cattle composed of Bos indicus and Bos taurus were artificially infested with 2,500 African blue tick, Rhipicephalus decoloratus larvae, with daily female tick (4.5 mm) counts taken from day 20 post-infestation. Volatile organic compounds were sampled from cattle before and after tick infestation by dynamic headspace collection, analysed by high-resolution gas chromatography (GC) and subjected to multivariate statistical analysis. Using 6-day repeated measure analysis, three pre-infestation GC peaks (BI938 - unknown, BI966 - 6-methyl-5-hepten-2-one and BI995 - hexyl acetate) and one post-infestation GC peak (AI933 - benzaldehyde / (E)-2-heptenal) were associated with tick resistance (P < 0.01 and P < 0.05 respectively). The high correlation coefficients (r = 0.66) between repeated records with all volatile compounds support the potential predictive value for volatile compounds in selective breeding programmes for tick resistance in cattle.

Comprehensive profiling of serotypes, antimicrobial resistance and virulence of Salmonella isolates from food animals in China, 2015-2021.

Introduction: Salmonella is a ubiquitous foodborne pathogen and mainly transmitted to human farm-to-fork chain through contaminated foods of animal origin. Methods: In this study, we investigated the serotypes, antimicrobial resistance and virulence of Salmonella from China. Results: A total of 617 Salmonella isolates were collected from 4 major food animal species across 23 provi nces in China from 2015-2021. Highest Salmonella prevalence were observed in Guangdong (44.4%) and Sandong (23.7%). Chickens (43.0%) was shown to be the major source of Salmonella contamination, followed by pigs (34.5%) and ducks (18.5%). The number of Salmonella increased significantly from 5.51% to 27.23% during 2015-2020. S. Derby (17.3%), S. Enteritidis (13.1%) and S. Typhimurium (11.4%) were the most common serotypes among 41 serotypes identifiedin this study. Antibiotic susceptibility testing showing that the majority of the Salmonella isolates were resistant to neomycin (99.7%), tetracycline (98.1%), ampicillin (97.4%), sulfadiazine/trimethoprim (97.1%), nalidixic acid (89.1%), doxycycline (83.1%), ceftria xone (70.3%), spectinomycin (67.7%), florfenicol (60.0%), cefotaxime (52.0%) and lomefloxacin (59.8%). The rates of resistance to multiple antibiotics in S. Derby and S.Typhimurium were higher than that in S. Enteritidis. However, the rate of resistance to fosfomycin were observed from higher to lower by S. Derby, S. Enteritidis, and S. Typhimurium. Biofilm formation ability analysis found that 88.49%of the Salmonella were able to produce biofilms, of which 236 Salmonella isolates were strong biofilm producer. Among the 26 types of antibiotics resistance genes (ARGs) were identified in this study, 4 ARGs (tetB,sul2,aadA2, and aph(3')-IIa) were highly prevalent. In addition, 5 ß-lactam resistance genes (bla TEM, bla SHV, bla CMY-2, bla CTX-M, and bla OXA) and 7 quinolone resistance genes (oqxA, oqxB, qnrB, qnrC, qnrD, qnrS, and qeqA) were detected among these isolates. 12 out of 17 virulence genes selected in this study were commonly presented in the chromosomes of tested isolate, with a detection rate of over 80%, including misL, spiA, stn, pagC, iroN, fim, msgA, sopB, prgH, sitC, ttrC, spaN. Discussion: This study provided a systematical updating on surveillance on prevalence of Salmonella from food animals in China, shedding the light on continued vigilance for Salmonella in food animals.

Epigenetic and Drug Response Modulation of Epigalocaten-In-3-Gallate in Staphylococcus aureus with Divergent Resistance Phenotypes.

Healthcare-associated methicillin-resistant Staphylococcus aureus infections represent extremely high morbidity and mortality rates worldwide. We aimed to assess the antimicrobial potential and synergistic effect between Epigalocatenin-3-gallate (EGCG) and different antibiotics in S. aureus strains with divergent resistance phenotypes. EGCG exposure effects in epigenetic and drug resistance key modulators were also evaluated. S. aureus strains (n = 32) were isolated from infected patients in a Lisbon hospital. The identification of the S. aureus resistance phenotype was performed through automatized methods. The antibiotic synergistic assay was performed through disk diffusion according to EUCAST guidelines with co-exposure to EGCG (250, 100, 50 and 25 µg/mL). The bacteria's molecular profile was assessed through FTIR spectroscopy. The transcriptional expression of OrfX, SpdC and WalKR was performed by using qRT-PCR. FTIR-spectroscopy analysis enabled the clear discrimination of MRSA/MSSA strains and the EGCG exposure effect in the bacteria's molecular profiles. Divergent resistant phenotypes were associated with divergent transcriptional expression of the epigenetic modulator OrfX, particularly in MRSA strains, as well as the key drug response modulators SpdC and WalKR. These results clearly demonstrate that EGCG exposure alters the expression patterns of key epigenetic and drug response genes with associated divergent-resistant profiles, which supports its potential for antimicrobial treatment and/or therapeutic adjuvant against antibiotic-resistant microorganisms.

Prevalence of Multidrug-Resistant Bacteria (Enteropathogens) Recovered from a Blend of Pig Manure and Pinewood Saw Dust during Anaerobic Co-Digestion in a Steel Biodigester.

South Africa adopts intensive livestock farming, embracing the employment of huge quantities of antibiotics to meet the increased demand for meat. Therefore, bacteria occurring in the animal products and manure might develop antibiotic resistance, a scenario which threatens public health. The study investigated the occurrence of Gram-negative bacteria from eighteen pooled samples withdrawn from a single-stage steel biodigester co-digesting pig manure (75%) and pine wood saw dust (25%). The viable counts for each bacterium were determined using the spread plate technique. The bacterial isolates were characterised based on cultural, morphological and biochemical characteristics, using the Analytical Profile Index 20 e test kit. In addition, isolates were characterised based on susceptibility to 14 conventional antibiotics via the disc diffusion method. The MAR index was calculated for each bacterial isolate. The bacterial counts ranged from 104 to 106 cfu/mL, indicating manure as a potential source of contamination. Overall, 159 bacterial isolates were recovered, which displayed diverse susceptibility patterns with marked sensitivity to amoxicillin (100% E. coli), streptomycin (96.15% for Yersinia spp.; 93.33% for Salmonella spp.) and 75% Campylobacter spp. to nitrofurantoin. Varying resistance rates were equally observed, but a common resistance was demonstrated to erythromycin (100% of Salmonella and Yersinia spp.), 90.63% of E. coli and 78.57% of Campylobacter spp. A total of 91.19% of the bacterial isolates had a MAR index > 0.2, represented by 94 MAR phenotypes. The findings revealed multidrug resistance in bacteria from the piggery source, suggesting they can contribute immensely to the spread of multidrug resistance; thus, it serves as a pointer to the need for the enforcement of regulatory antibiotic use in piggery farms. Therefore, to curb the level of multidrug resistance, the piggery farm should implement control measures in the study area.

Antimicrobial resistance analysis of Streptococcus suis strains isolated from human in Zhejiang Province / 中华传染病杂志

Objective:To understand the in vitro antimicrobial resistance and resistance phenotypes profile of Streptococcus suis strains isolated from human in Zhejiang Province. Methods:The strains of sporadic Streptococcus suis infections were isolated during 2005 to 2021 in Zhejiang Province, and were subjected to antimicrobial resistance analysis using agar dilution method. Polymerase chain reaction (PCR) technology was also used to detect 70 resistance genes including tetracyclines, macrolides and aminoglycosides. Results:The results of antimicrobial resistance analysis showed that these strains were sensitive to eleven kinds of antimicrobial agents with a sensitivity rate ≥96.8%, including cefepime, cefotaxime, ceftriaxone, chloramphenicol, daptomycin, ertapenem, levofloxacin, linezolid, meropenem, penicillin and vancomycin. These strains were mainly resistant to tetracycline, clindamycin, azithromycin and erythromycin, especially resistant to tetracycline with a rate of 93.5%(29/31). Fourteen strains (45.2%) exhibited multidrug resistant patterns. The PCR analysis of 70 drug resistance genes showed that 14(20.0%) different resistance genes were detected. The highest detection rate of resistant genes came from tetracycline, including tet ( O) gene (58.1%, 18/31), tet ( M) gene (48.4%, 15/31), tet ( 40) gene (35.5%, 11/31), followed by ermB gene (41.9%, 13/31) in the class of macrolide. Fourteen strains (45.2%) with more than three drug resistance genes were detected, of which eight strains (25.8%) detected 10 drug resistance genes. The analysis of antibiotic resistance and resistance phenotypes profile showed that tet ( M)+ ST7 accounted for 35.5%(11/31), tet( O)+ tet( 40)+ ermB+ mef( A)+ mef( A/ E)+ msrD+ Ant( 6)- Ⅰb+ aph( 3′)- Ⅲa+ aadB+ sat4+ ST7 accounted for 25.8%(8/31). Conclusions:The antimicrobial resistance and resistance phenotypes profile of sporadic Streptococcus suis strains isolated from human in Zhejiang Province are endemic, with mainly two types of characteristic genetic cloning of drug resistance genes.

Changes in antibiotic resistance genotypes and phenotypes after two typical sewage disposal processes.

Antibiotic resistome is a growing concern around the world. Wastewater treatment plants (WWTPs) have been identified as hotspots for antibiotic resistance gene (ARG) research. However, the distribution of antibiotic resistance genotypes and phenotypes in biofilm wastewater treatment system is poorly understood. In this study, the abundance and fate of antibiotic resistance genotypes and phenotypes in two typical wastewater treatment processes [biological aerated filter (BAF), anaerobic-oxic (A/O)] were quantitatively studied. The average removal rate of total ARGs was greater than 90%. In the biological treatment unit, the abundance of ARGs increased in the A/O unit and decreased in the biofilm unit. In addition, the resistance of tetracycline resistant bacteria changed after sewage disposal, which was closely related to the evolution of bacterial community. In total, the removal rate of resistance bacteria in A/O system was lower than that in BAF system. Genotypes were the basis of determining the phenotypes of microbial resistance. But it is necessary to pay close attention to antibiotic resistance phenotype due to its high variability. More specifically, antibiotic resistance mitigation in WWTPs should focus more on removing bacterial hosts to reduce the release of ARGs into the environment.

Direct antimicrobial susceptibility testing (AST) from positive blood cultures using Microscan system for early detection of bacterial resistance phenotypes.

Antimicrobial Susceptibility Testing is mandatory for Bloodstream Infections management in order to establish appropriate antimicrobial therapy. Herein we evaluated new approach based on AST results directly from positive blood cultures, using Microscan WA to carry out rapid phenotypical profile of antibiotic resistance. Our investigations allow to reduce time versus traditional results.

Drug-Induced Lipid Remodeling in Leishmania Parasites.

Leishmania parasites efficiently develop resistance against several types of drugs including antimonials, the primary antileishmanial drug historically implemented. The resistance to antimonials is considered to be a major risk factor for effective leishmaniasis treatment. To detect biomarkers/biopatterns for the differentiation of antimony-resistant Leishmania strains, we employed untargeted global mass spectrometry to identify intracellular lipids present in antimony sensitive and resistant parasites before and after antimony exposure. The lipidomic profiles effectively differentiated the sensitive and resistant phenotypes growing with and without antimony pressure. Resistant phenotypes were characterized by significant downregulation of phosphatidylcholines, sphingolipid decrease, and lysophosphatidylcholine increase, while sensitive phenotypes were characterized by the upregulation of triglycerides with long-chain fatty acids and a tendency toward the phosphatidylethanolamine decrease. Our findings suggest that the changes in lipid composition in antimony-resistant parasites contribute to the physiological response conducted to combat the oxidative stress unbalance caused by the drug. We have identified several lipids as potential biomarkers associated with the drug resistance.

Principal component analysis exploring the association between antibiotic resistance and heavy metal tolerance of plasmid-bearing sewage wastewater bacteria of clinical relevance.

This paper unravels the occurrence of plasmid-mediated antibiotic resistance in association with tolerance to heavy metals among clinically relevant bacteria isolated from sewage wastewater. The bacteria isolated were identified following conventional phenotypic and/or molecular methods, and were subjected to multiple-antibiotic resistance (MAR) profiling. The isolates were tested against the heavy metals Hg2+, Cd2+, Cr2+ and Cu2+. SDS-PAGE and agarose gel electrophoretic analyses were performed, respectively, for the characterization of heavy metal stress protein and R-plasmid among the isolated bacteria. Principal component analysis was applied in determining bacterial resistance to antibiotics and heavy metals. Both lactose-fermenting ( Escherichia coli ) and non-fermenting ( Acinetobacter baumannii and Pseudomonas putida ) Gram-negative bacterial strains were procured, and showed MAR phenotypes with respect to three or more antibiotics, along with resistance to the heavy metals Hg2+, Cd2+, Cr2+ and Cu2+. The Gram-positive bacteria, Enterococcus faecalis , isolated had 'ampicillin-kanamycin-nalidixic acid' resistance. The bacterial isolates had MAR indices of 0.3-0.9, indicating their ( E. faecalis , E. coli , A. baumannii and P. putida ) origin from niches with high antibiotic pollution and human faecal contamination. The Gram-negative bacteria isolated contained a single plasmid (≈54 kb) conferring multiple antibiotic resistance, which was linked to heavy metal tolerance; the SDS-PAGE analysis demonstrated the expression of heavy metal stress proteins (≈59 and ≈10 kDa) in wastewater bacteria with a Cd2+ stressor. The study results grant an insight into the co-occurrence of antibiotic resistance and heavy metal tolerance among clinically relevant bacteria in sewage wastewater, prompting an intense health impact over antibiotic usage.

Susceptibility to HIV-1 integrase strand transfer inhibitors (INSTIs) in highly treatment-experienced patients who failed an INSTI-based regimen.

The aim of this study was to characterize the genotypic and phenotypic resistance profile to the integrase strand transfer inhibitor (INSTI) bictegravir (BIC) and other INSTIs in patients who previously failed twice-daily raltegravir (RAL)-based or twice-daily dolutegravir (DTG)-based regimens. Twenty-two samples were collected after failure on an INSTI-based regimen in 17 highly treatment-experienced patients with HIV-1 with multi-drug-resistant virus, recorded in the Italian PRESTIGIO registry. Genotypic resistance mutations and phenotypic susceptibility to INSTIs were detected by GeneSeqIN and PhenoSenseIN assays, respectively (Monogram Biosciences, San Francisco, CA, USA). The primary INSTI resistance substitutions E138A/K, G140S, Y143C/H/R, Q148H and N155H were detected in 14 of 22 samples and were associated with resistance to one or more INSTIs, with G140S+Q148H present in 11 of 22 samples. Of these 14 samples, all showed high levels of resistance to elvitegravir (EVG) and RAL. Two isolates contained L74M, E138K, G140S and Q148H, or L74M, T97A, S119T, E138K, G140S, Y143R and Q148H, and had high-level resistance to all INSTIs, including BIC and DTG. Intermediate resistance was reported for eight of 14 isolates for BIC and nine of 14 isolates for DTG. Overall, for the 14 INSTI-resistant isolates, the median fold-change values in phenotypic susceptibility were: BIC 3.2 [interquartile range (IQR) 0.6-66], DTG 6.3 (IQR 0.8->186), EVG >164 (IQR 2.6->164) and RAL >188 (IQR 2.7->197). In conclusion, the study findings supported the in-vitro activity of BIC and DTG against most isolates derived from highly treatment-experienced patients who failed INSTI regimens.

Antimicrobial Susceptibility Testing for Corynebacterium Species Isolated from Clinical Samples in Romania.

Antimicrobial resistance is one of the most important public health issues. Besides classical multidrug resistance species associated with medical care involved in superficial or invasive infections, there are strains less commonly associated with hospital or outpatient setting's infections. Non-diphtheria Corynebacterium spp. could produce infections in patients with or without immune-compromised status. The aim of our study was to determine the susceptibility to antimicrobial agents to Corynebacterium spp. from clinical samples collected from Romanian hospitalized individuals and outpatients. Twenty Corynebacterium strains were isolated and identified as Corynebacterium striatum (n = 7), Corynebacterium amycolatum (n = 7), C. urealyticum (n = 3), Corynebacterium afermentans (n = 2), and Corynebacterium pseudodiphtheriticum (n = 1). All isolates have been tested for antibiotic susceptibility by standardized disc diffusion method and minimal inhibitory concentration (MIC) tests. Seventeen isolates demonstrated multidrug resistance phenotypes. The molecular support responsible for high resistance to quinolones for ten of these strains was determined by the detection of point mutation in the gene sequence gyrA.

Characterisation of Anopheles strains used for laboratory screening of new vector control products.

BACKGROUND: Insecticides formulated into products that target Anopheles mosquitos have had an immense impact on reducing malaria cases in Africa. However, resistance to currently used insecticides is spreading rapidly and there is an urgent need for alternative public health insecticides. Potential new insecticides must be screened against a range of characterized mosquito strains to identify potential resistance liabilities. The Liverpool School of Tropical Medicine maintains three susceptible and four resistant Anopheles strains that are widely used for screening for new insecticides. The properties of these strains are described in this paper. METHODS: WHO tube susceptibility bioassays were used for colony selection and to screen for resistance to the major classes of public health insecticides. Topical and tarsal contact bioassays were used to produce dose response curves to assess resistance intensity. Bioassays with the synergist piperonyl butoxide were also performed. Taqman™ assays were used to screen for known target site resistance alleles (kdr and ace-1). RT-qPCR was used to quantify expression of genes associated with pyrethroid resistance. RESULTS: Pyrethroid selection pressure has maintained resistance to this class in all four resistant strains. Some carbamate and organophosphate resistance has been lost through lack of exposure to these insecticide classes. The Anopheles gambiae (sensu lato) strains, VK7 2014, Banfora M and Tiassalé 13 have higher levels of pyrethroid resistance than the An. funestus FUMOZ-R strain. Elevated expression of P450s is found in all four strains and the 1014F kdr mutation is present in all three An. gambiae strains at varying frequencies. Tarsal contact data and overexpression of CYP4G16 and SAP2 suggest penetration barriers and/or sequestration also confer resistance in Banfora M. CONCLUSIONS: Continual selection with deltamethrin has maintained a stable pyrethroid-resistant phenotype over many generations. In conjunction with a standardized rearing regime, this ensures quality control of strains over time allowing for robust product comparison and selection of optimal products for further development. The identification of multiple mechanisms underpinning insecticide resistance highlights the importance of screening new compounds against a range of mosquito strains.

Prevalence of Genotypes That Determine Resistance of Staphylococci to Macrolides and Lincosamides in Serbia.

Macrolides, lincosamides, and streptogramins (MLS) resistance genes are responsible for resistance to these antibiotics in Staphylococcus infections. The purpose of the study was to analyze the distribution of the MLS resistance genes in community- and hospital-acquired Staphylococcus isolates. The MLS resistance phenotypes [constitutive resistance to macrolide-lincosamide-streptogramin B (cMLSb), inducible resistance to macrolide-lincosamide-streptogramin B (iMLSb), resistance to macrolide/macrolide-streptogramin B (M/MSb), and resistance to lincosamide-streptogramin A/streptogramin B (LSa/b)] were determined by double-disc diffusion method. The presence of the MLS resistance genes (ermA, ermB, ermC, msrA/B, lnuA, lnuB, and lsaA) were determined by end-point polymerase chain reaction in 179 isolates of staphylococci collected during 1-year period at the Center for Microbiology of Public Health Institute in Vranje. The most frequent MLS phenotype among staphylococcal isolates, both community-acquired and hospital-acquired, was iMLSb (33.4%). The second most frequent was M/MSb (17.6%) with statistically significantly higher number of hospital-acquired staphylococcal isolates (p < 0.05). MLS resistance was mostly determined by the presence of msrA/B (35.0%) and ermC (20.8%) genes. Examined phenotypes were mostly determined by the presence of one gene, especially by msrA/B (26.3%) and ermC (14.5%), but 15.6% was determined by a combination of two or more genes. M/MSb phenotype was the most frequently encoded by msrA/B (95.6%) gene, LSa/b phenotype by lnuA (56.3%) gene, and iMLSb phenotype by ermC (29.4%) and ermA (25.5%) genes. Although cMLSb phenotype was mostly determined by the presence of ermC (28.9%), combinations of two or more genes have been present too. This pattern was particularly recorded in methicillin-resistant Staphylococcus aureus (MRSA) (58.3%) and methicillin-resistant coagulase-negative staphylococci (MRCNS) (90.9%) isolates with cMLSB phenotype. The msrA/B gene and M/MSb phenotype were statistically significantly higher in hospital-acquired than community-acquired staphylococci strains (p < 0.05). There are no statistically significant differences between staphylococci harboring the rest of MLS resistance genes acquired in community and hospital settings (p > 0.05). The prevalence of iMLSb phenotypes may change over time, so it is necessary to perform periodic survey of MLS resistance phenotypes, particularly where the D-test is not performed routinely.

Macrolide-resistant Streptococcus pyogenes: prevalence and treatment strategies.

Although penicillin remains the first-choice treatment for Streptococcus pyogenes infection, macrolides are important alternatives for allergic patients and lincosamides are recommended together with ß-lactams in invasive infections. S. pyogenes may exhibit macrolide resistance because of active efflux (mef genes) or target modification (erm genes), the latter conferring cross resistance to lincosamides and streptogramin B. Worldwide, resistance is restricted to a limited number of genetic lineages, despite resistance genes being encoded on mobile genetic elements. For reasons that are not completely clear, resistance and the associated phenotypes are highly variable across countries. Although resistance remains high in several countries, particularly in Asia, an overall decreasing trend of resistance has been noted in recent years, mostly in Europe. This decrease is not always accompanied by declines in macrolide consumption, suggesting significant roles of other factors in determining the dynamics of macrolide-resistant clones. Continued surveillance is needed to obtain further insights into the forces governing macrolide resistance in S. pyogenes.

Infección por neisseria gonorrhoeaey fenotipos de resistencia antimicrobiana,Mar del Plata, 2005-2010 / Neisseria gonorrhoeae infection and phenotypes of antimicrobial resistance, Mar del Plata, 2005-2010 / Infecção por Neisseria gonorrhoeae e fenótipos de resistência antimicrobiana, Mar del Plata, 2005-2010

Se realizó un estudio epidemiológico de tipo descriptivo retrospectivo, para determinar la tasa de infección por Neisseria gonorrhoeae y sus fenotipos de resistencia a los antimicrobianos, en 666 pacientes adultos de ambos sexos que asistieron al servicio al Servicio de ITS del Instituto Nacional de Epidemiología "Dr. Juan H. Jara"- ANLIS "Dr. Carlos G. Malbrán", de la ciudad de Mar del Plata, entre los años 2005-2010. Para el diagnóstico de infección por N. gonorrhoeae, las muestras fueron obtenidas por hisopados endocervicales e hisopados uretrales a varones y luego cultivadas. Los aislamientos fueron remitidos al Laboratorio Nacional de Referencia en ITS para completar el estudio de sensibilidad antimicrobiana. Se obtuvo una tasa de infección por N. gonorrhoeae del 12,2% [IC 95%: 9,83-14,95]. Los fenotipos de resistencia más prevalentes resultaron QRNG/CMRNG (resistencia a quinolonas conjuntamente con resistencia cromosómica a penicilina y tetraciclina), QRNG (resistencia a quinolonas), PPNG (cepa productora de penicilinasa) y CMTR (resistencia cromosómica a tetraciclina). En el marco de la vigilancia epidemiológica de las infecciones producidas por N. gonorrhoeae, el rol del laboratorio consiste no sólo en monitorear la incidencia de casos en la población sino también el perfil de resistencia a los antibióticos de uso terapéutico, a fin de controlar la enfermedad.

An epidemiological retrospective descriptive study was conducted in order to determine the rate of Neisseria gonorrhoeae infection and the antimicrobial resistance phenotypes in 666 adult patients of both sexes who attended the Sexually Transmitted Disease Service, at the National Institute of Epidemiology "Dr. Juan H. Jara"- ANLIS city of Mar del Plata, between the years 2005- 2010. For the diagnosis of N. gonorrhoeae infection, samples were obtained by endocervical swabs and urethral swabs in men. Microbiological growth on selective culture medium was identified using carbohydrate utilization. N. gonorrhoeae isolates were subsequently submitted to the National Reference Laboratory in STI for the study of antimicrobial susceptibility by determining the minimum inhibitory concentration. The N. gonorrhoeae infection rate was 12.2% [CI 95%: 9.83-14.95]. The most prevalent resistance phenotypes were QRNG/CMRNG (quinolone resistance in addition to chromosomal resistance to penicillin and tetracycline), QRNG (resistance to quinolone), PPNG (penicillinase producing strain) and CMTR (chromosomal resistance to tetracycline). As part of the epidemiological surveillance of infections by N. gonorrhoeae, the role of the laboratory is not only to monitor the incidence of cases in the population but also the antibiotic resistance profile for therapeutic use, in order to control the disease.

Um estudo epidemiológico de tipo descritivo retrospectivo foi realizado para determinar a taxa de infecção por Neisseria gonorrhoeae e seus fenótipos de resistência aos antimicrobianos em 666 pacientes adultos de ambos os sexos que compareceram no Serviço de ITS do Instituto Nacional de Epidemiología "Dr. Juan H. Jara, ANLIS "Dr. Carlos G. Malbrán" da cidade de Mar del Plata, entre os anos de 2005-2010. Para o diagnóstico de infecção por N. gonorrhoeae, as amostras foram obtidas por esfregaços endocervicais e esfregaços uretrais em homens e em seguida cultivadas. Os isolados foram encaminhados para o Laboratório Nacional de Referência em ITS para completar o estudo da sensibilidade antimicrobiana. Uma taxa de infecção de 12,2% em N. gonorrhoeae [IC 95%: 9,83-14,95] foi obtida. Os fenótipos de resistência mais prevalentes foram QRNG/CMRNG (resistência às quinolonas em conjunto com a resistência cromossômica à penicilina e tetraciclina), QRNG (resistência a quinolonas), PPNG (cepa produtora de penicilinase) e CMTR (resistência cromossômica à tetraciclina). Sob o controle epidemiológico das infecções produzidas por N. gonorrhoeae, o papel do laboratório é não só monitorar a incidência de casos na população, mas também o perfil de resistência aos antibióticos de uso terapêutico, visando a controlar a doença.

Infección por Neisseria gonorrhoeae y fenotipos de resistencia antimicrobiana, Mar del Plata, 2005-2010 / Neisseria gonorrhoeae infection and phenotypes of antimicrobial resistance, Mar del Plata, 2005-2010 / InfecþÒo por Neisseria gonorrhoeae e fenótipos de resistÛncia antimicrobiana, Mar del Plata, 2005-2010

Se realizó un estudio epidemiológico de tipo descriptivo retrospectivo, para determinar la tasa de infección por Neisseria gonorrhoeae y sus fenotipos de resistencia a los antimicrobianos, en 666 pacientes adultos de ambos sexos que asistieron al servicio al Servicio de ITS del Instituto Nacional de Epidemiología "Dr. Juan H. Jara"- ANLIS "Dr. Carlos G. Malbrán", de la ciudad de Mar del Plata, entre los años 2005-2010. Para el diagnóstico de infección por N. gonorrhoeae, las muestras fueron obtenidas por hisopados endocervicales e hisopados uretrales a varones y luego cultivadas. Los aislamientos fueron remitidos al Laboratorio Nacional de Referencia en ITS para completar el estudio de sensibilidad antimicrobiana. Se obtuvo una tasa de infección por N. gonorrhoeae del 12,2% [IC 95%: 9,83-14,95]. Los fenotipos de resistencia más prevalentes resultaron QRNG/CMRNG (resistencia a quinolonas conjuntamente con resistencia cromosómica a penicilina y tetraciclina), QRNG (resistencia a quinolonas), PPNG (cepa productora de penicilinasa) y CMTR (resistencia cromosómica a tetraciclina). En el marco de la vigilancia epidemiológica de las infecciones producidas por N. gonorrhoeae, el rol del laboratorio consiste no sólo en monitorear la incidencia de casos en la población sino también el perfil de resistencia a los antibióticos de uso terapéutico, a fin de controlar la enfermedad.(AU)

An epidemiological retrospective descriptive study was conducted in order to determine the rate of Neisseria gonorrhoeae infection and the antimicrobial resistance phenotypes in 666 adult patients of both sexes who attended the Sexually Transmitted Disease Service, at the National Institute of Epidemiology "Dr. Juan H. Jara"- ANLIS city of Mar del Plata, between the years 2005- 2010. For the diagnosis of N. gonorrhoeae infection, samples were obtained by endocervical swabs and urethral swabs in men. Microbiological growth on selective culture medium was identified using carbohydrate utilization. N. gonorrhoeae isolates were subsequently submitted to the National Reference Laboratory in STI for the study of antimicrobial susceptibility by determining the minimum inhibitory concentration. The N. gonorrhoeae infection rate was 12.2% [CI 95%: 9.83-14.95]. The most prevalent resistance phenotypes were QRNG/CMRNG (quinolone resistance in addition to chromosomal resistance to penicillin and tetracycline), QRNG (resistance to quinolone), PPNG (penicillinase producing strain) and CMTR (chromosomal resistance to tetracycline). As part of the epidemiological surveillance of infections by N. gonorrhoeae, the role of the laboratory is not only to monitor the incidence of cases in the population but also the antibiotic resistance profile for therapeutic use, in order to control the disease.(AU)

Um estudo epidemiológico de tipo descritivo retrospectivo foi realizado para determinar a taxa de infecþÒo por Neisseria gonorrhoeae e seus fenótipos de resistÛncia aos antimicrobianos em 666 pacientes adultos de ambos os sexos que compareceram no Serviþo de ITS do Instituto Nacional de Epidemiología "Dr. Juan H. Jara, ANLIS "Dr. Carlos G. Malbrán" da cidade de Mar del Plata, entre os anos de 2005-2010. Para o diagnóstico de infecþÒo por N. gonorrhoeae, as amostras foram obtidas por esfregaþos endocervicais e esfregaþos uretrais em homens e em seguida cultivadas. Os isolados foram encaminhados para o Laboratório Nacional de ReferÛncia em ITS para completar o estudo da sensibilidade antimicrobiana. Uma taxa de infecþÒo de 12,2% em N. gonorrhoeae [IC 95%: 9,83-14,95] foi obtida. Os fenótipos de resistÛncia mais prevalentes foram QRNG/CMRNG (resistÛncia Os quinolonas em conjunto com a resistÛncia cromoss¶mica O penicilina e tetraciclina), QRNG (resistÛncia a quinolonas), PPNG (cepa produtora de penicilinase) e CMTR (resistÛncia cromoss¶mica O tetraciclina). Sob o controle epidemiológico das infecþ§es produzidas por N. gonorrhoeae, o papel do laboratório é nÒo só monitorar a incidÛncia de casos na populaþÒo, mas também o perfil de resistÛncia aos antibióticos de uso terapÛutico, visando a controlar a doenþa.(AU)

Antimicrobial resistance in commensal Escherichia coli isolated from animals at slaughter.

Monitoring of antimicrobial resistance in commensal Escherichia coli (N = 3430) isolated from slaughtered broilers, laying hens, turkeys, swine, and cattle in Poland has been run between 2009 and 2012. Based on minimal inhibitory concentration (MIC) microbiological resistance to each of 14 tested antimicrobials was found reaching the highest values for tetracycline (43.3%), ampicillin (42.3%), and ciprofloxacin (39.0%) whereas the lowest for colistin (0.9%), cephalosporins (3.6 ÷ 3.8%), and florfenicol (3.8%). The highest prevalence of resistance was noted in broiler and turkey isolates, whereas it was rare in cattle. That finding along with resistance patterns specific to isolation source might reflect antimicrobial consumption, usage preferences or management practices in specific animals. Regression analysis has identified changes in prevalence of microbiological resistance and shifts of MIC values. Critically important fluoroquinolone resistance was worrisome in poultry isolates, but did not change over the study period. The difference (4.7%) between resistance to ciprofloxacin and nalidixic acid indicated the scale of plasmid-mediated quinolone resistance. Cephalosporin resistance were found in less than 3.8% of the isolates but an increasing trends were observed in poultry and MIC shift in the ones from cattle. Gentamycin resistance was also increasing in E. coli of turkey and cattle origin although prevalence of streptomycin resistance in laying hens decreased considerably. Simultaneously, decreasing MIC for phenicols observed in cattle and layers isolates as well as tetracycline values in E. coli from laying hens prove that antimicrobial resistance is multivariable phenomenon not only directly related to antimicrobial usage. Further studies should elucidate the scope of commensal E. coli as reservoirs of resistance genes, their spread and possible threats for human and animal health.

Caracterización fenotípica de enterobacterias aisladas en pacientes con el virus de la inmunodeficiencia humana/sida / Phenotypic characterization of enterobacteria isolated from patients with human immunodeficiency virus infection/AIDS

Introducción: en pacientes con el virus de la inmunodeficiencia humana/sida se incrementa el riesgo de padecer infecciones por enterobacterias. Objetivo: caracterizar fenotípicamente las enterobacterias causantes de infecciones en estos pacientes. Métodos: se realizó un estudio descriptivo prospectivo, en el Instituto Pedro Kourí, de marzo de 2010 a marzo de 2011. Se procesaron muestras de esputo, lavado bronquial, secreciones faríngeas, óticas y vaginales, orina, fecales, lesiones de piel, sangre y catéteres, en 65 pacientes (ambulatorios y hospitalizados). La identificación bacteriológica y la susceptibilidad antimicrobiana de los 73 aislamientos, se determinaron mediante sistema VITEK 2 Compact (bioMérieux, Francia). Resultados: se identificaron Escherichia coli (30), Klebsiella spp. (19), Enterobacter spp. (15), Proteus spp. (7) y Serratia spp. (2). Prevalecieron las sepsis en pacientes hospitalizados (87,7 porciento). Menos de 50 porciento de las enterobacterias resultaron resistentes a las cefalosporinas, excepto Klebsiella spp. y Enterobacter spp. (68,4 porciento y 93,3 porciento de resistencia a cefepima y cefoxitina, respectivamente), y más del 80 porciento se mostró sensible a la amikacina. Se observó resistencia a piperazilina/tazobactam y ciprofloxacina en 27,3 porciento y 15 porciento, respectivamente. Se detectó 34,2 porciento de cepas productoras de betalactamasas de espectro extendido. Conclusiones: Escherichia coli y Klebsiella spp. causan frecuentemente infecciones en pacientes VIH/sida. El estudio de la sensibilidad antimicrobiana por VITEK 2 Compact, sugiere que las cefalosporinas, aminoglucósidos, quinolonas y piperacilina/tazobactam, pudieran constituir una alternativa terapéutica en estos casos

Introduction: the risk of infections caused by enterobacteria increases in HIV patients. Objective: to phenotypically characterize the enterobacteria responsible for infections in these patients. Methods: a prospective and descriptive study was conducted in Pedro Kourí Institute from March 2010 to March 2011. Samples of sputum, bronchial lavage, pharyngeal, ear and vaginal secretions, urine, stool, skin lesions, blood and catheters taken from 65 patients (ambulatory and hospital) were processed. Bacterial identification and antimicrobial susceptibility of 73 isolates were determined by automated system VITEK 2 Compact (bioMérieux, France). Results: Escherichia coli (30), Klebsiella spp. (19), Enterobacter spp. (15), Proteus spp. (7) and Serratia spp. (2) were identified. Sepsis in hospitalized patients (87.7 percent) was prevalent. Less than 50 percent of Enterobacteriaceae were resistant to cephalosporins, except Klebsiella spp. and Enterobacter spp. (68.4 percent and 93.3 percent resistance to cefepime and cefoxitin, respectively) and over 80 percent were sensitive to amykacin. Resistance to piperacillin/tazobactam and ciprofloxacin was observed in 27.3 percent and 15 percent of cases, respectively. In the study, 34.2 percent of extended-spectrum beta-lactamases- producing strains was detected. Conclusions: Escherichia coli and Klebsiella spp. often cause infections in HIV patients. The study of antimicrobial susceptibility by using VITEK 2 Compact system, suggests that cephalosporins, aminoglycosides, quinolones and piperacillin/tazobactam, could be effective therapeutic alternatives in these cases