Penicillinase-producing Neisseria gonorrhoeae conjunctivitis on some Nigerian children.

During 21 month study of bacterial conjunctivitis among 121 children in two health care centres in Calabar, Nigeria, a total of 90 (74.4%) cases were culturally confirmed. Neonates had the highest age-specific attack rates with 48 (53.3%) cases. Neisseria gonorrhoeae, the predominant pathogen, was recovered from 32 (35.6%) infections; 21 (65.6%) of them from neonates. Cultures of genital swabs of consenting parents of infected neonates as well as those of three female children aged 2-12 years with concurrent vulvo-vaginitis yielded N. gonorrhoeae. Younger women, mostly primi-gravidae were more frequently found to have benefited from peri-natal health care services than older multi-gravidae. Nevertheless, such access to health care services did not appear to influence the frequency of gonococcal conjunctivitis in neonates from the two maternal groups (P < 0.01). Sexual abuse and contaminated fomites were the possible modes of gonococcal infection transmission to older children. Overall, 22 (68.8%) strains of gonococci were resistant to penicillin; 19 (59.4%) were penicillinase-producing Neisseria gonorrhoeae (PPNG), while 5 (15.6%) had chromosomally-mediated resistance. All isolates were sensitive to erythromycin. This study recommends a review of gonorrhoea surveillance in pregnancy to include routine examination of cervical swabs just before delivery.     

Penicillinase-producing Neisseria gonorrhoeae in California. Report of a major outbreak and control recommendations.

A major outbreak of penicillinase-producing Neisseria gonorrhoeae occurred in California beginning in late 1986. After a state public health emergency was declared in April 1987, a statewide, cooperative federal-state-local treatment and control program was implemented. It was successful in reducing the reported incidence by 59%. Despite the success of this effort, penicillinase-producing N gonorrhoeae is not controlled in California, and, while not nearly the magnitude reported in Florida, an increasing number of cases are again being reported in California. We present recommendations for clinicians and local public health officials, including the epidemiologic and empiric treatment of suspected gonorrhea cases with ceftriaxone when the incidence of penicillinase-producing gonococcal cases in a community exceeds 1% of all reported gonorrhea cases.     

Penicillinase-producing Neisseria gonorrhoeae: a molecular comparison of 5.3-kb and 7.4-kb beta-lactamase plasmids.

Restriction endonuclease analysis and heteroduplex studies indicate that the only difference between the 5.3-kilobase (kb) and 7.4-kb plasmids from beta-lactamase-producing Neisseria gonorrhoeae is that the latter is the 5.3-kb plasmid with a 2.1-kb insertion. The insertion is bounded by inverted repeats of approximately 300 base pairs. Several plasmids from beta-lactamase-producing N. gonorrhoeae isolated at different times and in different countries were compared. Nine 5.3-kb plasmids were examined and found to be indistinguishable, as were sixteen 7.4-kb plasmids.     

Autoplaquing in Neisseria gonorrhoeae.

Irregularly shaped autoplaques were observed on a lawn of two different strains of Neisseria gonorrhoeae. Autoplaquing occurred on gonococcal genetic medium lacking arginine and was noninducible on complete gonococcal genetic medium. The cell density, incubation temperature, and agar base influenced autoplaquing. Single-colony suspensions varied in plaque morphology. We were unable to isolate a stable nonplaquing variant but separated strain RUN5287 into two plaquing phenotypes.     

Conjugative plasmids in Neisseria gonorrhoeae.

A conjugation system initially discovered in beta-lactamase-producing gonococci mobilized small non-selftransmissible R plasmids encoding beta-lactamase (penicillinase) production into other gonococci, Neisseria, and Escherichia coli. This conjugation system was mediated by a separate selftransmissible plasmid of 23.9 X 10(6) daltons, pFA2. Conjugative plasmids capable of mobilizing R plasmids were also found in nearly 8% of the non-penicillinase-producing gonococci. These were similar to pFA2 in size, buoyant density, and restriction endonuclease digest patterns but were less efficient than pFA2 in mobilization of the penicillinase plasmid pFA3. The presence of conjugative plasmids in gonococci isolated before the appearance of penicillinase-producing strains indicates that a conjugation system for plasmid transfer predated the appearance of R plasmids in gonococci.     

Autolysis of Neisseria gonorrhoeae.

Autolysis of Neisseria gonorrhoeae was studied under different conditions. It was found that low pH and temperature, as well as the presence of divalent cations, spermine, sucrose, and polyvinylpyrrolidone, stabilized nongrowing gonococci. Ethylenediaminetetraacetic acid alone promoted lysis, whereas lysozyme had only a limited additive effect. The autolytic behavior of gonococci appears to be connected with their prolonged cell division process. The relative dependence on the outer membrane and the peptidoglycan layer for the mechanical stability of gonococci is discussed.     

Autolysis of Neisseria gonorrhoeae.

Physiological conditions that would provide maximal rates of autolysis of Neisseria gonorrhoeae were examined. Autolysis was found to occur over a broad pH range with the optimum at pH 9.0 IN 0.05 M tris(hydroxymethyl)amino-methane-maleate buffer. The temperature optimum was found to be 40 C. Potassium ions greatly stimulated autolysis at a concentration of 0.01 M. Exposure of growing N. gonorrhoeae cells to penicillin, vancomycin, or D-cycloserine influenced the susceptibility to the autolysis, whereas chloramphenicol afforded some protection against autolysis. The primary structure of the peptidoglycan is composed of muramic acid/glutamic acid/alanine/diaminopimelic acid/glucosamine in approximate molar ratios of 1:1:2:1:1, respectively. Exogenous radioactive diaminopimelic acid, D-glucosamine, and D-alanine were incorporated into peptidoglycan. During autolysis these radioactive fragments were released from cells.     

Penicillinase-producing Neisseria gonorrhoeae in Great Britain, 1977-81: alarming increase in incidence and recent development of endemic transmission.

Since penicillinase-producing Neisseria gonorrhoeae appeared five years ago in West Africa and South-east Asia reported cases have doubled annually in Great Britain, primarily as a result of increasing importation. Importation of penicillinase-producing Neisseria gonorrhoeae has increased exponentially because dramatic expansion of these strains in their regions of origin has led to increasing infection of male air travellers. From 1977 to 1980 infections acquired in Great Britain played only a minor part in the exponential increase. During 1981 the number of indigenous cases increased much more rapidly than imported cases, indicating that these strains have become truly endemic in Great Britain. Currently, identification of patients at high risk and initial treatment with penicillinase-resistant antibiotics offers the best hope of containing the strains. The emergence and rapid spread of penicillinase-producing Neisseria gonorrhoeae shows the international consequences of the abuse of antibiotics.     

Genetic exchange mechanisms in Neisseria gonorrhoeae.

There are two mechanisms for genetic exchange in Neisseria gonorrhoeae. Plasmid deoxyribonucleic acid can be transferred by conjugation, which is dependent on the presence of a 24.5-megadalton plasmid in the donor cell. We have shown that chromosomal deoxyribonucleic acid can be exchanged between all colonial variants by transformation, but not by conjugation. In the nonpiliated variants, however, this exchange was dependent on the presence of the 24.5-megadalton plasmid in the recipient cell.     

Temperature-sensitive mutants of Neisseria gonorrhoeae.

Nine temperature-sensitive (Ts) mutants of Neisseria gonorrhoeae strain 49191 were isolated. They were proven to be different from each other by results of transformation experiments. None of the Ts mutations appeared to be linked to antibiotic resistance genes from strain 24392. However, Ts-9 demonstrated 8% linkage with a nalidixic acid resistance marker from strain RW-2.     

Plasmid-mediated chromosomal gene transfer in Neisseria gonorrhoeae.

An indigenous Neisseria gonorrhoeae conjugative plasmid, pLE2450, was tested for its ability to mediate chromosomal gene transfer between gonococcal strains. Plasmid-mediated chromosomal transfer was detected at a low frequency and can be used to establish certain linkage relationships between amino acid and antibiotic resistance markers.     

Glucose Metabolism in Neisseria gonorrhoeae

The metabolism of glucose was examined in several clinical isolates of Neisseria gonorrhoeae. Radiorespirometric studies revealed that growing cells metabolized glucose by a combination on the Entner-Doudoroff and pentose phosphate pathways. A portion of the glyceraldehyde-3-phosphate formed via the Entner-Doudoroff pathway was recycled by conversion to glucose-6-phosphate. Subsequent catabolism of this glucose-6-phosphate by either the Entner-Doudoroff or pentose phosphate pathways yielded CO(2) from the original C6 of glucose. Enzyme analyses confirmed the presence of all enzymes of the Entner-Doudoroff, pentose phosphate, and Embden-Meyerhof-Parnas pathways. There was always a high specific activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) relative to that of 6-phosphogluconate dehydrogenase (EC 1.1.1.44). The glucose-6-phosphate dehydrogenase utilized either nicotinamide adenine dinucleotide phosphate or nicotinamide adenine dinucleotide as electron acceptor. Acetate was the only detectable nongaseous end product of glucose metabolism. Following the disappearance of glucose, acetate was metabolized by the tricarboxylic acid cycle as evidenced by the preferential oxidation of [1-(14)C]acetate over that of [2-(14)C]acetate. When an aerobically grown log-phase culture was subjected to anaerobic conditions, lactate and acetate were formed from glucose. Radiorespirometric studies showed that under these conditions, glucose was dissimilated entirely by the Entner-Doudoroff pathway. Further studies determined that this anaerobic dissimilation of glucose was not growth dependent.     

Mechanism of autolysis of Neisseria gonorrhoeae.

The major autolysin(s) of Neisseria gonorrhoeae was solubilized from envelopes by extraction with 2% Triton X-100 containing 0.5 M NaCl. Neither Triton X-100 nor NaCl alone could effectively release the autolysin(s). The major autolysin is N-acetylmuramyl-L-alanine amidase (EC 3.5.1.28). The pH optimum for this reaction was broad, ranging from 5.5 to 8.5. Optimal hydrolysis of peptidoglycan occurred in 2% Triton X-100 in 0.1 M KCl. Attempts to purify the autolysin were unsuccessful. A rapid assay for enzyme activity was developed using radioactive cell walls as a substrate ([3H]diaminopimelic acid).