Ceftazidime/avibactam resistance is associated with PER-3-producing ST309 lineage in Chilean clinical isolates of non-carbapenemase producing Pseudomonas aeruginosa.

Introduction: Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant Pseudomonas aeruginosa, particularly those that are carbapenem resistant. CZA resistance in P. aeruginosa producing PER, a class A extended-spectrum ß-lactamase, has been well documented in vitro. However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing P. aeruginosa clinical isolates that were ceftazidime and/or carbapenem non-susceptible. Methods: Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while bla PER gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of bla PER-3 gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics. Results: Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried bla PER. One isolate carried bla PER but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their bla PER-3 gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum ß-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of bla PER-3 gene restored susceptibility to CZA, ceftolozane/tazobactam and other ß-lactamsin the in vitro evolved isolate. Discussion: PER-3-producing ST309 P. aeruginosa is a successful multidrug-resistant clone with blaPER-3 gene implicated in resistance to CZA and other ß-lactams.

A multispecies outbreak of carbapenem-resistant bacteria harboring the blaKPC gene in a non-classical transposon element.

BACKGROUND: Klebsiella pneumoniae is the most frequent KPC-producing bacteria. The blaKPC gene is frequently embedded in Tn4401 transposon, and less frequently in non-Tn4401 elements (NTEKPC) variants I-III. The first case of KPC in the UC-CHRISTUS Clinical Hospital was detected in Pseudomonas aeruginosa. Soon after this event, KPC was detected in 2 additional Pseudomonas aeruginosa, 3 Escherichia coli, 3 Enterobacter cloacae, 3 Klebsiella pneumoniae, and 1 Citrobacter freundii, isolated from 6 different patients. We aimed to elucidate the possible mechanisms of genetic transfer and dissemination of the blaKPC gene among isolates of this multispecies outbreak. A molecular epidemiology analysis of the above mentioned clinical isolates (n = 13) through Multi-Locus Sequence Typing, plasmid analysis, Pulsed-Field Gel-Electrophoresis, and Whole-genome sequencing (WGS) was performed. RESULTS: High-risk sequence types were found: K. pneumoniae ST11, P. aeruginosa ST654, and E. cloacae ST114. All enterobacterial isolates were not clonal except for 3 E. coli isolated from the same patient. WGS analysis in 6 enterobacterial isolates showed that 4 of them had blaKPC embedded in a novel variant of NTEKPC designated NTEKPC-IIe. Upstream of blaKPC gene there was a 570 pb truncated blaTEM-1 gene followed by an insertion sequence that was 84% similar to ISEc63, a 4473 bp element of the Tn3 family. Downstream the blaKPC gene there was a truncated ISKpn6 gene, and the inverted repeat right sequence of Tn4401. The ISec63-like element together with the blaKPC gene plus Tn4401 remnants were inserted in the Tra operon involved in conjugative transfer of the plasmid. This NTE was carried in a broad host-range IncN plasmid. P. aeruginosa isolates carried blaKPC gene embedded in a typical Tn4401b transposon in a different plasmid, suggesting that there was no plasmid transfer between Enterobacteriaceae and P. aeruginosa as initially hypothesized. CONCLUSIONS: Most enterobacterial isolates had blaKPC embedded in the same NTEKPC-IIe element, suggesting that this multispecies KPC outbreak was due to horizontal gene transfer rather than clonal spread. This poses a greater challenge to infection control measures often directed against containment of clonal spread.

Clinical and microbiological response of mice to intranasal inoculation with Lactococcus lactis expressing Group A Streptococcus antigens, to be used as an anti-streptococcal vaccine.

Protein subunit vaccines are often preferred because of their protective efficacy and safety. Lactic acid bacteria expressing heterologous antigens constitute a promising approach to vaccine development. However, their safety in terms of toxicity and bacterial clearance must be evaluated. Anti-Streptococcus pyogenes (S. pyogenes) vaccines face additional safety concerns because they may elicit autoimmune responses. The assessment of toxicity, clearance and autoimmunity of an anti-streptococcal vaccine based on Lactococcus lactis (L. lactis) expressing 10 different M protein fragments from S. pyogenes (L. lactis-Mx10) is here reported. Clearance of L. lactis from the oropharynges of immunocompetent mice and mice devoid of T/B lymphocytes mice was achieved without using antibiotics. The absence of autoimmune responses against human tissues was demonstrated with human brain, heart and kidney. Assessment of toxicity showed that leucocyte counts and selected serum biochemical factors were not affected in L. lactis-Mx10-immunized mice. In contrast, mice immunized with L. lactis wild type vector (L. lactis-WT) showed increased neutrophil and monocyte counts and altered histopathology of lymph nodes, lungs and nasal epithelium. Two days after immunization, L. lactis-Mx10-immunized and L. lactis-WT-immunized mice weighed significantly less than unimmunized mice. However, both groups of immunized mice recovered their body weights by Day 6. Our results demonstrate that L. lactis-WT, but not the vaccine L. lactis-Mx10, induces alterations in certain hematologic and histopathological variables. We consider these data a major contribution to data on L. lactis as a bacterial vector for vaccine delivery.

Protective immunity induced by an intranasal multivalent vaccine comprising 10 Lactococcus lactis strains expressing highly prevalent M-protein antigens derived from Group A Streptococcus.

Streptococcus pyogenes (group A Streptococcus) causes diseases ranging from mild pharyngitis to severe invasive infections. The N-terminal fragment of streptococcal M protein elicits protective antibodies and is an attractive vaccine target. However, this N- terminal fragment is hypervariable: there are more than 200 different M types. In this study, an intranasal live bacterial vaccine comprising 10 strains of Lactococcus lactis, each expressing one N-terminal fragment of M protein, has been developed. Live bacterial-vectored vaccines cost less to manufacture because the processes involved are less complex than those required for production of protein subunit vaccines. Moreover, intranasal administration does not require syringes or specialized personnel. Evaluation of individual vaccine types (M1, M2, M3, M4, M6, M9, M12, M22, M28 and M77) showed that most of them protected mice against challenge with virulent S. pyogenes. All 10 strains combined in a 10-valent vaccine (M×10) induced serum and bronchoalveolar lavage IgG titers that ranged from three- to 10-fold those of unimmunized mice. After intranasal challenge with M28 streptococci, survival of M×10-immunized mice was significantly higher than that of unimmunized mice. In contrast, when mice were challenged with M75 streptococci, survival of M×10-immunized mice did not differ significantly from that of unimmunized mice. Mx-10 immunized mice had significantly less S. pyogenes in oropharyngeal washes and developed less severe disease symptoms after challenge than did unimmunized mice. Our L. lactis-based vaccine may provide an alternative solution to development of broadly protective group A streptococcal vaccines.

Possible mechanism by which zinc protects the testicular function of rats exposed to cigarette smoke.

BACKGROUND: The aim of this study was to evaluate the changes in testicular function of rats due to cigarette smoke exposure and the possible mechanism by which zinc protects against these alterations. METHODS: Male Wistar rats (60 days old) were randomly divided into 3 groups: control (G1, n = 10); exposed to cigarette smoke (G2, n = 10; 20 cigarettes/day/9 weeks) and exposed to cigarette smoke and supplemented with zinc (G3, n = 8; 20 cigarettes/day/9 weeks; 20 mg/kg zinc chloride daily for 9 weeks, by gavage). After the treatment period, the animals were euthanized, and materials were collected for analyses. RESULTS: G2 rats showed a reduction in body mass; impaired sperm concentration, motility, morphology and vitality; and increased malonaldehyde and thiol group levels and superoxide dismutase activity as compared to G1. Zinc prevented the reduction of sperm concentration and the excessive increase of lipid peroxidation and induced an increase in plasma testosterone levels, wet weight of testis and thiol group concentration. CONCLUSIONS: Exposure to cigarette smoke led to harmful effects on testicular function at least partially due to the exacerbation of oxidative stress. Supplementary zinc had an important modulator/protector effect on certain parameters. The mechanism of zinc protection can be through an increase of SH concentration. Thus, zinc supplementation may be a promising addition to conventional treatments for male infertility related to smoking.

Copulatory efficiency and fertility in male rats exposed perinatally to flutamide.

This study investigated the effects of perinatal treatment with flutamide on male sexual behavior, semen parameters, and fertility in adult male rats. Pregnant rats received 15 mg/kg of flutamide or peanut oil, s.c., at days 19 and 22 of pregnancy and for the first five postnatal days. Treated male offspring showed increases in latency to copulatory behavior, number of mounts without penis intromission, number of intromissions until ejaculation, latency to ejaculation, and reduced number of ejaculations. Flutamide treated rats presented reductions in weight of testes and prostate, percentage of normal spermatozoa, spermatozoa concentration, testicular sperm production, and testosterone level. Normal females mated with treated males presented more pre-implantation losses, reduced implantation rates, and consequently reduced offspring size. The results indicated that perinatal flutamide treatment damaged organizational processes of sexual differentiation, which led to inefficiency in copulatory behavior and reductions in sperm quality and count, resulting in low capacity for producing descendants.

Semen parameters, fertility and testosterone levels in male rats exposed prenatally to betamethasone.

The present study investigated the long-term effects of prenatal betamethasone exposure on sperm quality and count, fertility and plasma testosterone levels in adult male rats. Pregnant rats received 0.1 mg kg(-1) betamethasone on Days 12, 13, 18 and 19 of pregnancy. This treatment impaired sperm quality, sperm production, fertility and plasma testosterone levels in adult male offspring compared to the control group. Thus, the results of the present study indicate that the long-term effects of prenatal betamethasone exposure may be deleterious to offspring. The consequent decrease in testosterone production during adulthood, in association with damaged semen parameters, may explain for the observed decrease in the capacity of adult male offspring to themselves generate viable descendants.

Adult partner preference and sexual behavior of male rats exposed prenatally to betamethasone.

The aim of this study was to investigate long-term effects of prenatal betamethasone exposure on sexual partner preference, testosterone level, and sexual behavior. Pregnant rats received 0.1 mg/kg of betamethasone or saline on the 12th, 13th, 18th, and 19th days of pregnancy. Parameters in male offspring were evaluated at 90 days of age. Male rats from the betamethasone group did not show any difference in sexual partner preference as expressed by the total number of visits to the female or male zone. However, these males spent significantly less total time and shorter duration per visit in the female zone than their controls. Therefore, prenatal exposure to betamethasone led to a significantly lower sexual female partner preference score compared to the control group. These animals also presented diminished testosterone levels in adulthood. Prenatal exposure to betamethasone induced a delay in the latency to first ejaculation, as well as a decrease in the numbers of postejaculatory intromissions, total intromissions and total ejaculations. Although 80% of the betamethasone-treated animals exhibited male sexual behavior, when they were castrated and pretreated with estrogen, 50% of them showed lordosis and accepted mounts of another sexually experienced male. These results suggest that the prenatal treatment with betamethasone, by increasing maternal corticosteroid level, may have diminished testosterone peak in male pups, a peak crucial to brain sexual differentiation. As a consequence, the prenatal betamethasone treatment reduced the testosterone level in adulthood and altered partner preference and sexual behavior.

[Assessment of the Amplicor PCR for the detection of Mycobacterium tuberculosis in smear negative respiratory and non respiratory specimens: a retrospective analysis]. / Análisis retrospectivo del rendimiento de Amplicor-PCR para la detección de Mycobacterium tuberculosis en muestras respiratorias y no respiratorias con baciloscopia negativa.

BACKGROUND: Commercial polymerase chain reaction (PCR) kits are widely accepted for analysis of smear positive respiratory specimens, but the sensitivity is variable for smear negative ones. OBJECTIVE: To assess the PCR method usefulness in smear negative respiratory and non respiratory specimens. METHODS: We compared the PCR results (AMPLICOR MTB test, Roche) of 235 specimens subjected to culture in Loewenstein-Jensen agar (as the gold standard). RESULTS: 181 (76%) were respiratory and 54 (24%) extra-respiratory specimens. The sensitivity was 88%) and 50%>, respectively, specificity and PPV was 100%> in both cases. NPV was 99.4%> in respiratory specimens and 96.1% in non-respiratory specimens. CONCLUSIONS: The good performance of this PCR in smear negative respiratory specimens allows the clinician to take decisions based on the result of this exam. In extra-respiratory specimens the contribution is important only when the PCR result is positive.

[Antimicrobial susceptibility of Campylobacter jejuni isolates from stool cultures in Santiago, Chile]. / Susceptibilidad antimicrobiana de Campylobacter jejuni aislado de coprocultivos en Santiago de Chile.

Campylobacter jejuni is a common agent of enterocolitis in humans. Campylobacteriosis has been recognized as a zoonotic disease whose reservoir is the intestinal flora of poultry. The reposition of fluid and electrolytes is the recommended treatment, and antimicrobials are required only in severe and/or in prolonged disease. Given the emergence of resistance to drugs commonly used in the treatment of acute diarrhea, we studied the antimicrobial susceptibility of 73 strains of Campylobacter jejuni isolated from stool culture. The antimicrobials tested were: erythromycin, azithromycin, ampicillin and ciprofloxacin. Of the 73 strains tested by E-test, 32.4% were resistant to ciprofloxacin and 6.4% were resistant to ampicillin. Resistance to erythromycin and azithromycin was not detected. The surveillance of antimicrobial resistance of Campylobacter jejuni is important in the evaluation of empirically used antimicrobials in the treatment of bacterial enterocolitis.

Effects of maternal exposure to an aromatase inhibitor on sexual behaviour and neurochemical and endocrine aspects of adult male rat.

The present study examined the effects of letrozole exposure during brain sexual differentiation on endocrine, behavioural and neurochemical parameters in male rat descendants. Pregnant female rats received 1 mg kg(-1) day(-1) letrozole or vehicle by oral gavage on gestational Days 21 and 22. Exposure to letrozole reduced anogenital distance in males on postnatal Day (PND) 22. At adulthood (PND 75), plasma testosterone levels and hypothalamic dopaminergic activity were increased, but sexual competence was impaired, because fewer successful sexual behaviours (mount, intromission and principally ejaculation) were observed. The impairment of reproductive function by prenatal exposure to an aromatase inhibitor reinforces the importance of adequate oestrogenic activity during perinatal sexual differentiation for complete masculinisation of the hypothalamus.

Antisperm antibodies in infertile men and their correlation with seminal parameters.

Aim: Antisperm antibodies (ASA) in males cause the autoimmune disease 'immune infertility'. The present study intended to detect the presence of ASA and their incidence in men with unexplained infertility, as well as to evaluate the correlation between the presence of ASA and semen parameter alterations. Methods: Blood and sperm assessment were collected to carry out a direct and indirect mixed antiglobulin reaction (MAR) test and semen analysis in infertile and fertile men from the University Hospital of the Faculty of Medicine, Sao Paulo State University, Sao Paulo. Results: In the MAR test, 18.18% of infertile men were positive for ASA. In fertile men, no positivity was found. A significant correlation between the presence of ASA with an increased white blood cell count plus a decreased hypoosmotic swelling test result was observed. Conclusions: The results indicate that ASA are involved in reduced fertility. It is not ASA detection per se that provides conclusive information about the occurrence of damage to fertility. The correlation between infertility and altered seminal parameters reinforce the ASA participation in this pathology. (Reprod Med Biol 2007; 6: 33-38).