Serogrouping of Neisseria gonorrhoeae: correlation of serogroup with disseminated gonococcal infection

An optimized Factor H-Fc fusion protein against multidrug-resistant Neisseria gonorrhoeae

Novel therapeutics against the global threat of multidrug-resistant Neisseria gonorrhoeae are urgently needed. Gonococci evade killing by complement by binding factor H (FH), a key inhibitor of the alternative pathway. FH comprises 20 short consensus repeat (SCR) domains organized as a single chain. Gonococci bind FH through domains 6 and 7, and C-terminal domains 18 through 20. Previously, we showed that a chimeric protein comprising (from the N- to C-terminus) FH domains 18-20 (containing a point mutation in domain 19 to prevent lysis of host cells) fused to human IgG1 Fc (called FH*/Fc1) killed gonococci in a complement-dependent manner and reduced the duration and bacterial burden in the mouse vaginal colonization model of gonorrhea. Considering the N. gonorrhoeae-binding FH domains 18-20 are C-terminal in native FH, we reasoned that positioning Fc N-terminal to FH* (Fc1/FH*) would improve binding and bactericidal activity. Although both molecules bound gonococci similarly, Fc1/FH* displayed a 5-fold lower IC50 (the concentration required for 50% killing in complement-dependent bactericidal assays) than FH*/Fc1. To further increase complement activation, we replaced human IgG1 Fc in Fc1/FH* with Fc from human IgG3, the most potent complement-activating IgG subclass, to obtain Fc3/FH*. Bactericidal activity was further increased ~2.3-fold in Fc3/FH* compared to Fc1/FH*. Fc3/FH* killed (defined by <50% survival) 45/45 (100%) diverse PorB1B-expessing gonococci, but only 2/15 PorB1A-expressing isolates, in a complement-dependent manner. Decreased Fc3/FH* binding accounted for the limited activity against PorB1A strains. Fc3/FH* was efficacious against all four tested PorB1B gonococcal strains in the mouse vaginal colonization model when administered at a dose of 5 µg intravaginally, daily. Furthermore, Fc3/FH* retained bactericidal activity when reconstituted following lyophilization or spray-drying, suggesting feasibility for formulation into intravaginal rings. In conclusion, Fc3/FH* represents a promising prophylactic immunotherapeutic against multidrug-resistant gonococci.

Cervicovaginal Microbiota Predicts Neisseria gonorrhoeae Clinical Presentation

Neisseria gonorrhoeae infection of the female lower genital tract can present with a spectrum of phenotypes ranging from asymptomatic carriage to symptomatic cervical inflammation, or cervicitis. The factors that contribute to the development of asymptomatic or symptomatic infections are largely uncharacterized. We conducted a pilot study to assess differences in the cervicovaginal microbial community of patients presenting with symptomatic vs. asymptomatic N. gonorrhoeae infections to a sexually transmitted infections (STI) clinic. DNA was isolated from cervicovaginal swab specimens from women who tested positive for N. gonorrhoeae infection using a clinical diagnostic nucleic acid amplification test. We performed deep sequencing of 16S ribosomal RNA gene amplicons, followed by microbiome analyses with QIIME, and species-specific real-time PCR to assess the composition of microbial communities cohabitating the lower genital tract with the infecting N. gonorrhoeae. Specimens collected from asymptomatic individuals with N. gonorrhoeae infection and no co-infection with Chlamydia trachomatis and/or Trichomonas vaginalis carried Lactobacillus-dominant microbial communities more frequently than symptomatic patients without co-infection. When compared to asymptomatic individuals, symptomatic women had microbial communities characterized by more diverse and heterogenous bacterial taxa, typically associated with bacterial vaginosis (BV) [Prevotella, Sneathia, Mycoplasma hominis, and Bacterial Vaginosis-Associated Bacterium-1 (BVAB1)/"Candidatus Lachnocurva vaginae"]. Both symptomatic and asymptomatic N. gonorrhoeae patients with additional STI co-infection displayed a BV-like microbial community. These findings suggest that Lactobacillus-dominant vaginal microbial community may protect individuals from developing symptoms during lower genital tract infection with N. gonorrhoeae.

Disseminated Gonococcal Infection Complicated by Prosthetic Joint Infection: Case Report and Genomic and Phylogenetic Analysis

Neisseria gonorrhoeae infections have been increasing globally, with prevalence rising across age groups. In this study, we report a case of disseminated gonococcal infection (DGI) involving a prosthetic joint, and we use whole-genome sequencing to characterize resistance genes, putative virulence factors, and the phylogenetic lineage of the infecting isolate. We review the literature on sequence-based prediction of antibiotic resistance and factors that contribute to risk for DGI. We argue for routine sequencing and reporting of invasive gonococcal infections to aid in determining whether an invasive gonococcal infection is sporadic or part of an outbreak and to accelerate understanding of the genetic features of N gonorrhoeae that contribute to pathogenesis.

Innate recognition by neutrophil granulocytes differs between Neisseria gonorrhoeae strains causing local or disseminating infections

Members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family serve as cellular receptors for Neisseria gonorrhoeae. More specifically, neisserial colony opacity (OpaCEA)) proteins bind to epithelial CEACAMs (CEACAM1, CEA, CEACAM6) to promote bacterial colonization of the mucosa. In contrast, recognition by CEACAM3, expressed by human granulocytes, results in uptake and destruction of Opa(CEA)-expressing bacteria. Therefore, CEACAM3-mediated uptake might limit the spread of gonococci. However, some strains can cause disseminating gonococcal infections (DGIs), and it is currently unknown how these strains escape detection by granulocyte CEACAM3. Therefore, the opa gene loci from N. gonorrhoeae strain VP1, which was derived from a patient with disseminated gonococcal disease, were cloned and constitutively expressed in Escherichia coli. Similar to Opa proteins of the nondisseminating strain MS11, the majority of Opa proteins from strain VP1 bound epithelial CEACAMs and promoted CEACAM-initiated responses by epithelial cells. In sharp contrast to the Opa proteins of strain MS11, the Opa proteins of strain VP1 failed to interact with the human granulocyte receptor CEACAM3. Accordingly, bacteria expressing VP1 Opa proteins were not taken up by primary human granulocytes and did not trigger a strong oxidative burst. Analysis of Opa variants from four additional clinical DGI isolates again demonstrated a lack of CEACAM3 binding. In summary, our results reveal that particular N. gonorrhoeae strains express an Opa protein repertoire allowing engagement of epithelial CEACAMs for successful mucosal colonization, while avoiding recognition and elimination via CEACAM3-mediated phagocytosis. A failure of CEACAM3-mediated innate immune detection might be linked to the ability of gonococci to cause disseminated infections.

Factor H facilitates adherence of Neisseria gonorrhoeae to complement receptor 3 on eukaryotic cells

Neisseria gonorrhoeae can engage human complement receptor 3 (CR3) directly or through surface-bound iC3b. Factor H (fH) that binds to bacteria facilitates conversion of C3b to iC3b. fH also binds directly to CR3 on professional phagocytes. Certain nonprofessional phagocytes, such as primary cervical epithelial cells, also express CR3. We hypothesized that fH could bridge bacteria to CR3 and facilitate gonococcal association with host cells. Specificity of the fH-CR3 interaction was confirmed using human CR3-transfected Chinese hamster ovary (CHO-CR3) cells. Using recombinant proteins that comprised contiguous fH domains (fH contains 20 short consensus repeat [SCR] domains) fused to murine Fc, we observed strong binding through SCRs 18-20, whereas weaker binding occurred through SCRs 6-10. Both regions also bound to unsialylated porin (Por) B.1A-expressing N. gonorrhoeae. Accordingly, fH-related protein 1 (three of its five SCRs are highly homologous to fH SCRs 18-20) bound to CHO-CR3 and to unsialylated PorB.1A gonococci. An alternatively spliced variant of fH called fH-like protein-1 (contains fH SCRs 1-7) bound to gonococci but minimally to CHO-CR3. An fH SCRs 6-20 construct enhanced binding of unsialylated PorB.1A gonococci to CHO-CR3. However, a construct that contained only the apparently relevant SCRs (6, 7, and 18-20) bound to CHO-CR3 and to gonococci separately, but did not enhance bacteria-CR3 interactions, suggesting that the intervening SCRs (8-17) may impart a configurational and spatial requirement for fH to bridge gonococci to CR3. These results indicate adherence between fH-coated gonococci and CR3 and may provide a means for gonococci to gain sanctuary into nonprofessional phagocytes.

Molecular surveillance of clinical Neisseria gonorrhoeae isolates in Russia

The choice of adequate methods for epidemiological purposes remains a challenging problem in Neisseria gonorrhoeae molecular monitoring. In this study, the collection of geographically unrelated gonococci (n = 103) isolated in Russian clinics was comparably tested by (i) a traditional serotyping scheme, (ii) por typing, (iii) Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST), and (iv) multilocus sequence typing (MLST). It is shown that, according to sequencing data, a third of the strains carried new porB1 alleles, as well as tbpB ones, and more than half of the samples had new sequence types (STs) as determined by NG-MAST or MLST. The discriminatory power for each typing method was calculated by using the Hunter-Gaston discriminatory index, D. Commonly, modern nucleic acid-based typing methods (por typing, NG-MAST, and MLST) appeared to be more efficient than the classical serotyping scheme. While the traditional serotyping gave a D value of 0.82, the por typing, NG-MAST, and MLST approaches yielded D values of 0.97, 0.98, and 0.91, respectively. Each typing technique revealed the distribution of gonococci slightly correlated with their geographical sources. However, only the MLST method STs were highly associated with certain phenotypes. Although ST1594, ST1892, and ST6720 were typical for susceptible gonococci, ST1901 and ST6716 were undoubtedly associated with a multidrug-resistant phenotype. We conclude that every tested nucleic acid-based typing method is suitable for N. gonorrhoeae molecular surveillance. However, the MLST method seems to serve large-scale epidemiological purposes, whereas the NG-MAST and por typing approaches are more appropriate for the investigation of local outbreaks.

Methods for typing std pathogens (N. Gonorrhoeae, C. Trachomatis, T. Pallidum)

Phenotypic methods were initially used for bacterial typing yet they have a number of drawbacks limiting their use. Methods of molecular and genetic typing have become wide-spread today. Among these methods, bacterial typing based on multilocus sequence typing (Multilocus Sequence Typing - MLST) has been developing at the fastest rate. However, schemes of molecular and genetic typing of STD pathogens as compared to other bacteria are insufficiently developed, which considerably complicates the planning of measures aimed at the reduction of their spread.

Evaluation of PorB variable region typing of Neisseria gonorrhoeae using PCR-ELISA in samples collected from men who have sex with men

A polymerase chain reaction (PCR)-based enzyme-linked immunosorbent assay (ELISA) methodology was developed to characterize Neisseria gonorrhoeae porB gene variable regions (VR); the methodology was evaluated in comparison to porB VR typing by checkerboard hybridization. Clinical noncultured samples from 35 men who have sex with men (MSM), positive by nucleic amplification assays for N. gonorrhoeae, were typed using a panel of 40 oligonucleotide probes to porB VRs and compared to checkerboard hybridization. Complete concordance was observed between the two methods at PIB VRs 1, 3, and 7. At the more degenerate VRs 5 and 6, PCR ELISA resulted in obtaining more typeable VRs than checkerboard hybridization due to single nucleotide mismatches. By PCR ELISA, two predominant PIB porB types were identified in 58% of the samples and the remaining 16 samples had one of six other porB types. Both PCR ELISA and checkerboard hybridization methods of porB VR typing allowed characterization of N. gonorrhoeae from noncultured clinical samples including throat and rectal swabs and discriminated N. gonorrhoeae from N. meningitidis present in some of the samples. PCR ELISA is a rapid, relatively inexpensive and alternative molecular typing method for N. gonorrhoeae, suitable for use in conjunction with molecular diagnostic tests.

Neisseria gonorrhoeae population in Arkhangelsk, Russia: phenotypic and genotypic heterogeneity

Reliable data concerning the incidence and phenotypic and genotypic characteristics of the Neisseria gonorrhoeae population in many eastern European countries are lacking. Clinically significant N. gonorrhoeae isolates (n = 76) from 76 consecutive patients in Arkhangelsk, Russia were characterised by antimicrobial susceptibility testing, serovar determination, porB gene sequencing and N. gonorrhoeae multi-antigen sequence typing (NG-MAST). The isolates were assigned to 12 different serovars, displayed 35 divergent porB sequences, and belonged to 40 different sequence types (STs). All the serovars, but only seven of the STs, had been identified previously in other countries. Twelve ST clusters of between two and 14 isolates were identified, which indicated that many multiple transmission networks exist in Arkhangelsk. The high number of unique STs (n = 28) may be a consequence of sub-optimal diagnostic procedures, ineffective partner tracing, local emergence of new STs, import of strains via sexual tourists, or foreign travel. The N. gonorrhoeae population circulating in Arkhangelsk was highly diverse and differed from the N. gonorrhoeae populations disseminated in some western European countries. Thorough knowledge concerning the incidence of gonorrhoea, antibiotic susceptibility and other phenotypic and genotypic characteristics of the N. gonorrhoeae strains circulating in eastern Europe is crucial.

Genetic typing of the porin protein of Neisseria gonorrhoeae from clinical noncultured samples for strain characterization and identification of mixed gonococcal infections

Molecular methods that characterize the Neisseria gonorrhoeae porin protein Por are needed to study gonococcal pathogenesis in the natural host and to classify strains from direct clinical samples used with nucleic acid amplification-based tests. We have defined the capabilities of por variable region (VR) typing and determined suitable conditions to apply the method to direct clinical specimens. Nested PCR from spiked urine samples detected 1 to 10 copies of template DNA; freezing spiked whole urine greatly reduced the ability to amplify porB. In a laboratory model of mixed gonococcal infections, the por type of one strain could be determined in the presence of a 100-fold excess of another. por VR typing was used to examine clinical samples from women enrolled in studies conducted in Baltimore, Md., and Madagascar. por type was determined from 100% of paired cervical swab and wick samples from 20 culture-positive women from Baltimore; results for eight individuals (40%) suggested infection with more than one strain. In frozen urine samples from Madagascar, porB was amplified and typed from 60 of 126 samples from ligase chain reaction (LCR)-positive women and 3 samples from LCR-negative women. The por VR types of 13 samples (21%) suggested the presence of more than one gonococcal strain. Five por types, identified in >45% of women with typed samples, were common to both geographic areas. Molecular typing is an important adjunct to nucleic acid amplification-based diagnostics. Methods that utilize direct clinical samples and can identify mixed infections may contribute significantly to studies of host immunity, gonococcal epidemiology, and pathogenesis.

Experimental gonococcal urethritis and reinfection with homologous gonococci in male volunteers

BACKGROUND

Reinfection, a common occurrence with gonorrhea, may result from a lack of protective immune response, or from the tremendous gonococcal strain variation.

GOAL

A two-phase study in human volunteers tested whether experimental infection with Neisseria gonorrhoeae MS11mkC would protect against reinfection with the same organisms.

STUDY DESIGN

In phase 1, an intraurethral inoculum of 57,000 piliated, transparent (opacity protein-negative [Opa-]) MS11mkC N gonorrhoeae infected 14 of 15 (93%) volunteers. The volunteers were encouraged to delay treatment for at least 5 days. In phase 2, which began 2 weeks after treatment for the initial infection, volunteers were inoculated with 7,100 piliated, Opa- MS11mkC.

RESULTS

The phase 2 challenge infected 6 of 14 (43%) previously infected volunteers and 5 of 10 (50%) naïve control subjects. Phase 1 volunteers who resisted reinfection were significantly more likely to have had a fourfold or greater increase in lipooligosaccharide immunoglobulin G during phase 1 than those who did not resist reinfection (P = 0.026).

CONCLUSIONS

Although infection did not provide protection from reinfection under the conditions used, the results suggest that immunity to reinfection is more complex than anticipated by the experimental design.

Interaction of the gonococcal porin P.IB with G- and F-actin

The invasion of epithelial cells by N. gonorrheae is accompanied by formation of a halo of actin filaments around the enveloped bacterium. The transfer of the bacterial major outer membrane protein, porin, to the host cell membrane during invasion makes it a candidate for a facilitator for the formation of this halo. Western analysis shows here that gonococcal porin P.IB associates with the actin cytoskeleton in infected cells. Using the pyrene-labeled Mg forms of yeast and muscle actins, we demonstrate that under low ionic strength conditions, P.IB causes formation of filamentous actin assemblies, although they, unlike F-actin, cannot be internally cross-linked with N,N'-4-phenylenedimaleimide (PDM). In F-buffer, low porin concentrations appear to accelerate actin polymerization. Higher P.IB concentrations lead to the formation of highly decorated fragmented F-actin-like filaments in which the actin can be cross-linked by PDM. Co-assembly of P.IB with a pyrene-labeled mutant actin, S(265)C, prevents formation of a pyrene excimer present with labeled S(265)C F-actin alone. Addition of low concentrations of porin to preformed F-actin results in sparsely decorated F-actin. Higher P.IB concentrations extensively decorate the filaments, thereby altering their morphology to a state like that observed when the components are copolymerized. With preformed labeled S(265)C F-actin, P.IB quenches the pyrene excimer. This decrease is prevented by the F-actin stabilizers phalloidin and to a lesser extent beryllium fluoride. P.IB's association with the actin cytoskeleton and its ability to interact with and remodel actin filaments support a direct role for porin in altering the host cell cytoskeleton during invasion.

Population genetics of the porB gene of Neisseria gonorrhoeae: different dynamics in different homology groups

The porB locus codes for the major outer membrane protein of Neisseria gonorrhoeae. Alleles of this locus have been assigned to two homology groups based on close sequence and immunological relationships and are designated as either PIA or PIB. Several population parameters were estimated and compared among these two groups using a data set of 22 PIA sequences and 91 PIB sequences obtained from diverse geographic localities and from time periods spanning approximately 50 years. Recombination appears to be extensive in the porB gene. While the recombination rates are similar for the PIA and PIB sequences, the relative contribution of recombination to genetic diversity is higher for the PIA sequences. Alleles belonging to the PIB group show greater genetic diversity than do those in the PIA group. Although phylogenetic analysis did not reveal temporal or geographic clustering of sequences, estimates of gene flow and the fixation index suggested that PIB sequences exhibit population substructure based on geographic locality. Selection acts in these homology groups in a different way. While positive Darwinian selection is the dominant force driving the evolution of the PIA sequences, purifying selection operates also on the PIB sequences. These differences may be attributable to the greater propensity of PIA strains, as compared with PIB strains, to cause disseminated gonococcal infection, which would expose the former to intense selection pressure from the host immune system. The molecular evolution of Neisseria gonorrhoeae seems to be driven by the simultaneous action of selection and recombination, but under different rates and selection pressures for the PIA and PIB homology groups.

Experimental transmission of Neisseria gonorrhoeae from pregnant rat to fetus

Sprague-Dawley rats were infected on day 20 of pregnancy by intraperitoneal inoculation with Neisseria gonorrhoeae. Disseminated gonococcal infection (DGI) and pelvic inflammatory disease (PID) strains in the presence of C1q but not in the presence of bovine serum albumin (BSA) were able to spread from the pregnant rat to the fetus and resulted in fetal mortality. Transmission of DGI and PID strains that are serum resistant (ser(r)) and sac-4 positive but not of a local infection strain that is ser(s) and sac-4 negative was facilitated by the C1q-dependent mechanism. This study provides the first experimental model that may mimic the transmission of gonococcal infection from mother to the fetus during pregnancy.

Neisseria gonorrhoeae porin modulates phagosome maturation

The porin (PorB) of Neisseria gonorrhoeae has been implicated in the pathogenesis of this species. Porin is believed to translocate from the bacterial outer membrane into target cell membranes affecting various cell functions. Here we investigated the effect of porin on phagosome maturation. Phagocytosis of latex beads by human macrophages was allowed in the presence or absence of purified porin. Isolation of latex bead-containing phagosomes and subsequent two-dimensional gel electrophoresis revealed substantial differences in the phagosomal protein composition. Immunoblotting detected higher amounts of annexin II and the early endocytic markers Rab5 and transferrin receptor and decreased levels of the late endocytic markers Rab7 and cathepsin D in phagosomes obtained in the presence of porin compared with those obtained in its absence. Furthermore, association of Rab4 with the latex bead-containing phagosomes was revealed by flow cytometry. The amount of this small GTPase was markedly higher in the phagosomes isolated in the presence of porin. The data thus indicate that neisserial porin is itself able to arrest phagosome maturation within macrophages.

Gonococcal invasion of epithelial cells driven by P.IA, a bacterial ion channel with GTP binding properties

The neisserial porin P.I is a GTP binding protein that forms a voltage-gated channel that translocates into mammalian cell membranes and modulates host cell signaling events. Here, we report that P.I confers invasion of the bacterial pathogen Neisseria gonorrhoeae into Chang epithelial cells and that this event is controlled by GTP, as well as other phosphorus-containing compounds. Bacterial invasion was observed only for strains carrying the P.IA subtype of porin, which is typically associated with the development of disseminated neisserial disease, and did not require opacity outer membrane proteins, previously recognized as gonococcal invasins. Allelic replacement studies showed that bacterial invasiveness cotransferred with the P.IA (por1A) gene. Mutation of the P.I-associated protein Rmp did not alter the invasive properties. Cross-linking of labeled GTP to the porin revealed more efficient GTP binding to the P.IA than P.IB porin subtype. GTP binding was inhibited by an excess of unlabeled GTP, ATP, and GDP, as well as inorganic phosphate, but not by UTP or beta-glycerophosphate, fully in line with the respective invasion-inhibitory activities observed for these compounds. The P.IA-mediated cellular invasion may explain the more invasive behavior of P.IA strains in the natural infection and may broaden the basis for the development of a P.I-based gonococcal vaccine.

Gonococcal arthritis

Disseminated gonococcal infection is the most common systemic complication of acute gonorrhea and occurs in 0.5% to 3.0% of patients with untreated mucosal infection. It is also the most common cause of septic arthritis in patients less than 30 years of age. Fortunately, the incidence of gonorrhea is decreasing dramatically in the United States and Western Europe, although it is still high in developing countries. Increasing resistance to antibiotics requires continuous surveillance of antimicrobial susceptibilities to determine the efficacy of current therapeutic measures.

Antibiotic susceptibilities, serotypes and auxotypes of Neisseria gonorrhoeae isolated in New Zealand

OBJECTIVE

The aim of the study was to determine the distribution of auxotypes and serotypes and the prevalence of antibiotic resistance among New Zealand isolates of Neisseria gonorrhoeae.

MATERIALS AND METHODS

A total of 486 gonococci isolated in 1988 were auxotyped, serotyped, and tested for susceptibilities to ten antibiotics.

RESULTS

The gonococci were susceptible to all the antibiotics tested except penicillin and tetracycline. Eleven (2.2%) produced beta-lactamase, one (0.2%) showed chromosomal penicillin resistance, and 18 (3.7%) were resistant to a low-level of tetracycline. Most of the gonococci belonged to six auxotypes. The three predominant auxotypes were arginine-requiring (Arg-), non-requiring (NR), and arginine, hypoxanthine, uracil-requiring (AHU-). The majority of the isolates belonged to serogroup IB and to six serovars. The most prevalent serovars were IB-3 and IB-1. There was an association between penicillin susceptibility and auxotype or serovar among non-penicillinase producing N. gonorrhoeae (PPNG) isolates.

CONCLUSIONS

Antibiotic resistance, including penicillin resistance, remains uncommon among gonococci in New Zealand. Baselines have been established for future epidemiological studies using both auxotyping and serotyping.

Fate of the major outer membrane protein P.IA in early and late events of gonococcal infection of epithelial cells

We investigated the fate of the major outer membrane protein of Neisseria gonorrhoeae, P.IA, during gonococcal infection of Chang conjunctiva epithelial cells by using immunoelectron microscopy. Probing of P.IA epitopes with mono- and polyclonal antibodies revealed variable, fixation-dependent P.IA epitope exposure in the gonococci used as an inoculum in the infection experiments. Detection of invariable exposed P.IA epitopes in cryosections of infected epithelial cells with a polyclonal antiserum revealed unaltered P.IA exposure on the bacterial membranes during early attachment of the bacteria to the eukaryotic cells. Upon entry of the bacteria into the host cells, however, labelling was extended to membraneous structures that intercalated between the bacteria and the host cell surface, and, occasionally, to the host cell plasma membrane. The latter observation is consistent with the suggested active role of P.I. in the uptake process (as shown in 1985 by E.C. Gotschlich). Once inside the epithelial cells, both morphologically intact and disintegrating bacteria could be distinguished. The disintegration of the bacteria was accompanied by a loss of P.IA immunoreactivity.

Serological classification in relation to auxotypes, plasmid contents, and susceptibilities to antimicrobials of PPNG and non-PPNG strains isolated in Greece

Thirty three penicillinase producing Neisseria gonorrhoeae (PPNG) and 152 non-PPNG strains were serologically classified in relation to their patterns of resistance to antimicrobials, nutritional requirements (auxotypes), and plasmid contents. Of the 185 strains, 65 (35%) belonged to the WI and 120 (65%) to the WII/III serogroup, the predominant serovars of which were Arost and Bropt, respectively. Associations between serotype and susceptibility to antimicrobial agents, auxotype, and plasmid content were observed. Of the 152 non-PPNG strains, 112 (74%) belonged to serogroup WI. The WI non-PPNG strains were more sensitive to penicillin, thiamphenicol, tetracycline, and cefotaxime than the WII/III non-PPNG strains. Auxotyping and serogrouping the strains showed no differentiation other than that arginine, hypoxanthine, and uracil dependent (AHU-) strains belonged to serogroup WI. The proline, citrulline, and uracil dependent (PCU-) strains belonged, as expected, to serogroup WII/III. Analysing the 33 PPNG strains showed that of 21 carrying the 4.5 megadalton (Asian type) penicillin resistance plasmid, 17 (81%) belonged to serogroup WI, with serovar Arst predominating, and only four (19%) to serogroup WII/III. Of 11 isolates carrying the 3.2 megadalton (African type) resistance plasmid, seven (64%) belonged to serogroup WI (serovar Av predominating) and four (36%) to WII/III (with serovar Bropyst predominating). One strain carried the 3.05 megadalton penicillin resistance plasmid (Toronto type), belonged to the WI serogroup, and had serovar Arost.

Protein I: structure, function, and genetics

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