PD-140248 is an isomerase inhibitor and topoisomerase II inhibitor under development by Parke-Davis and Co as a potential treatment for bacterial infection. Although no details of active development have been published in the scientific literature since 1996, in September 1999, the company confirmed that PD-140248 is still in active development [338530]. The compound is one of two new pyrrolidinyl naphthyridines (the other compound being PD-131628) with a broad spectrum of antibacterial activity, including activity against quinolone-resistant bacteria. PD-140248 demonstrates strong in vitro activity, particularly against Gram-positive bacteria, such as quinolone-susceptible Staphylococcus aureus (S aureus), Staphylococcus epidermidis (S epidermidis), Staphylococcus haemolyticus (S haemolyticus), methicillin- and ciprofloxacin-resistant S aureus, Streptococcus species, Streptococcus pneumoniae (S pneumoniae) and Enterococcus faecalis (E faecalis). An MIC90 value of 0.015 microg/ml was obtained against Haemophilus influenzae (H influenzae) and Moraxella catarrhalis [160129]. The (3R,1S) enantiomer, PD-140248, demonstrated a 1- to 10-fold enhanced activity against Gram-positive and Gram-negative organisms in vitro and in vivo compared to its stereoisomers, and has thus been targeted for further preclinical studies [133377].

A multiplex polymerase chain reaction (PCR) that can simultaneously detect eubacterial isolates and the methicillin-susceptibility of staphylococcal isolates from cerebrospinal and peritoneal fluid samples was compared to conventional microbiological methods. Using conventional methods, bacteria were isolated from 8% (29/350) of the cerebrospinal fluid samples and from 5% (3/60) of the peritoneal fluid samples. All isolates except twoStaphylococcus epidermidis isolates were also detected using the multiplex PCR. Coagulase-negative staphylococci andStaphylococcus aureus were correctly identified using both methods. The multiplex PCR can rapidly and simultaneously detect eubacteria, and the methicillin susceptibility of staphylococci from samples containing ≥102 cfu/ml of bacteria.

As well as conventional methods such as immunodiffusion, ELISA, or agglutination for the detection of toxin production in Staphylococcus aureus, amplification techniques like PCR allow a very sensitive and specific identification of the genes responsible for enterotoxin B and C, and TSST-1 production. These toxins might be a cause of the toxic shock syndrome (TSS). For that reason an easy and quick test system for determining the toxin production pattern of S. aureus isolates is desirable so that strains suspected to be toxin producers may be identified much faster and easier. In the present investigation, a new multiplex-PCR method was used that allowed single bacterial colonies grown on agar plates to be used directly in the PCR assay without preceding preparation. This procedure generated information concerning the presence of seb, sec-1 and tst genes within 4 h in a single test. To analyse the sensitivity and the specificity of this procedure, 100 methicillin-resistant S. aureus (MRSA), 50 coagulase-negative staphylococci and 50 other eubacterial isolates were tested initially with sets of single primer pairs followed by a combined multiplex-PCR. Results of this amplification technique were compared to a conventional and widely used method for toxin detection, reversed passive latex agglutination (RPLA). With the RPLA assay results as the basis, sensitivity and specificity of the seb and tst primer sets were 100%, whereas sensitivity and specificity of the sec-1 primer set were 100% and 82%, respectively. With the sec-1 primer set, two isolates were identified as carrying the corresponding toxin gene although the RPLA test did not show any detectable toxin. The multiplex-PCR rapidly generated reliable information concerning the toxin-producing capacity of staphylococcal strains and could be easily integrated into a multiplex procedure described previously. The latter enabled the identification of specific PCR products for eubacteria and staphylococci as well as the detection of the coa and mecA genes.

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) represent an increasing problem in hospitals. Quick and reliable typing methods are required to obtain information about the relatedness of MRSA isolates and to allow faster implementation of appropriate infection control measures. This investigation describes the distribution of MRSA isolates from 11 hospitals in the Düsseldorf region of Germany, and the ability of six different genotypic typing techniques -- pulsed-field gel electrophoresis (PFGE), random amplification of polymorphic DNA (RAPD), 16S-23S rDNA spacer amplification, protein A-gene PCR, PCR characterisation of the hypervariable region (HVR) adjacent to mecA, and coagulase gene-PCR -- to detect different unrelated types. Of 7814 S. aureus isolates tested, 489 (6.3%) were MRSA, of which 183 were selected for subsequent molecular analyses on the basis of being the first MRSA isolated from colonised or infected patients. Larger hospitals had a higher incidence of MRSA and a greater variability in genotypes than smaller hospitals. All methods confirmed the presence of two main clonal types. The ability of techniques to detect different unrelated types was found to be as follows: PFGE, 28 types; 16S-23S rDNA spacer-amplification, 10 types; RAPD, nine types; protein A-gene PCR, five types; HVR-PCR, five types; and coa gene-PCR, two types. Combination of PFGE and one other PCR-based method (spacer-amplification, RAPD or protein-A gene PCR) provided the best resolution of types and allowed the identification of subtypes. Similar molecular types were identified with international MRSA isolates. Although PCR-based techniques have the advantage of rapid performance and easy handling, their discriminatory capacity is inferior compared to the more labour intensive PFGE.

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) represent an increasing problem in hospitals. Quick and reliable typing methods are required to obtain information about the relatedness of MRSA isolates and to allow faster implementation of appropriate infection control measures. This investigation describes the distribution of MRSA isolates from 11 hospitals in the Dusseldorf region of Germany, and the ability of six different genotypic typing techniques - pulsed-field gel electrophoresis (PFGE), random amplification of polymorphic DNA (RAPD), 16s23s rDNA spacer amplification, protein A-gene PCR, PCR characterisation of the hypervariable region (HVR) adjacent to mecA, and coagulase gene-PCR - to detect different unrelated types. Of 7814 S. aureus isolates tested, 489 (6.3%) were MRSA, of which 183 were selected for subsequent molecular analyses on the basis of being the first MRSA isolated from colonised or infected patients. Larger hospitals had a higher incidence of MRSA and a greater variability in genotypes than smaller hospitals. All methods confirmed the presence of two main clonal types. The ability of techniques to detect different unrelated types was found to be as follows: PFGE, 28 types; 16s-23s rDNA spacer-amplification, 10 types; RAPD, nine types; protein A-gene PCR, five types; HVR-PCR, five types; and coa gene-PCR, two types. Combination of PFGE and one other PCR-based method (spacer-amplification, RAPD or protein-A gene PCR) provided the best resolution of types and allowed the identification of subtypes. Similar molecular types were identified with international MRSA isolates. Although PCR-based techniques have the advantage of rapid performance and easy handling, their discriminatory capacity is inferior compared to the more labour intensive PFGE.