Coagulase-negative Staphylococcal Septicemia Research Articles

The mouth as a source of coagulase negative staphylococcal septicaemia in low birth weight neonates

The mouth as a source of coagulase negative staphylococcal septicaemia in low birth weight neonates

Antibody responses and opsonic activity in sera of preterm neonates with coagulase-negative staphylococcal septicemia and the effect of the administration of fresh frozen plasma.

Coagulase-negative staphylococcal septicemia is the most prominent nosocomial infection in neonatal intensive care units. Immaturity of host defenses in premature neonates is assumed to constitute an important risk factor. Opsonophagocytosis is considered to be the key host defense system against staphylococci with IgG antibodies as a major opsonin. For this reason we have studied serum IgG antibody titers and opsonic activity to coagulase-negative staphylococci in 20 infants with septicemia and 40 matched control subjects. In addition, we assessed the effect of administration of fresh frozen plasma (FFP) on IgG antibody titer and serum opsonic activity in 12 patients with septicemia. IgG antibodies, quantified by ELISA and opsonic activity, determined by flow cytometry, were expressed as a percentage of the value of pooled normal human reference serum. Both patients and control subjects showed low IgG titers (median, 21%; range, 1-192%) and a low opsonic activity (median, 33%; range, 8-484%) at birth. During the first 2 postnatal wk IgG titers decreased significantly in septicemia patients (from a median of 30 to 17%, p = 0.025), but not in control subjects, whereas opsonic activity remained unchanged. The titer of IgG antibodies increased significantly in septicemia patients after FFP administration (from a median of 17 to 41%, p = 0.002), whereas the effect on opsonic activity was unpredictable, showing a moderate increase in 10 out of 12 infants, and in 2 patients even a substantial decrease (>50%), despite adequate opsonic activity in the corresponding FFP batches. Immunoblotting of sepsis isolates with the corresponding patient sera demonstrated that septicemic infants may generate IgG antibodies against their blood isolate. Neonates who acquire coagulase-negative staphylococcal septicemia cannot be distinguished from control subjects on the basis of IgG antibodies and opsonic activity to staphylococci either at birth or during the first 2 postnatal wk. The administration of FFP to septicemia neonates has an unpredictable effect on opsonic activity and therefore does not seem to be a useful addition to antibiotic therapy.

Clinical outcome of cephalothin (C) versus vancomycin (V) therapy in the treatment of coagulase-negative staphylococcal (CONS) septicemia in neonates: relation to methicillin resistance (MR) and mec A gene carriage (mAGC) of blood isolates. • 1322

CONS are the most important causative agents of nosocomial septicemia in neonatal intensive care units with an incidence of 10% in our unit. We use C as primary antibiotic therapy for nosocomial infections, but increasing usage of V was observed during the last few years. This is due to increasing MR of CONS blood isolates, to 72% in 1995. In addition, increasing mAGC, determined by targeted PCR, was noted for CONS blood isolates from 58% in 1986 to 91% in 1995. There is still debate about the use of first generation cephalosporins in the treatment of MR-CONS infections. Therefore, we have evaluated the outcome of C versus V therapy of CONS neonatal septicemia in relation to MR, C susceptibility and mAGC of CONS isolates for 1994 and 1995. Data of 63 CONS septicemia patients (65 episodes) were studied. In 51 (78%) episodes C was used, in 24 of these (36%) as primary therapy, in 27(42%) treatment was switched from C to V, because of susceptibility results in 16 (60%), clinical picture in 7 (26%), combination of these two in 2 (7%) and in 2 (7%) it was not specified. V as primary therapy was used in 14 episodes(22%). In both C and V categories time for clinical recovery was similar(2.1±1.3 and 2.5±2.7 days, resp.) as was time to CRP normalization (5.5±1.8 and 6.5±3.1 days, resp.). In the 24 episodes treated with C these data were similar between C-susceptible (14 episodes) and C-resistant categories (10 episodes) (clinical recovery after 1.9±1.1 and 2.4±1.5 days, resp., CRP normal after 5.3±2.2 and 5.6±1.3 days, resp.). In the 27 episodes in which C was switched to V, clinical recovery occurred before switch in 12 (44%). Conclusions: 1. Mec A gene carriage of CONS blood isolates has increased considerably to >90% in 1995. 2. Equal clinical outcome of cephalothin or vancomycin therapy of CONS septicemia in neonates, despite almost universal mec A gene carriage of CONS blood isolates. 3.Cephalothin is a valuable alternative to vancomycin in the treatment of CONS septicemia in neonates.

Microbial characteristics and severity of coagulase-negative staphylococcal septicaemia in premature neonates.

A pilot study was undertaken to assess the predictive value of characteristics possessed by coagulase-negative staphylococci in determining clinically important infection in premature neonates. No significant association was demonstrated between organism properties and clinical indices of infection. The routine use of simple measures of microbial characteristics in the assessment of neonatal septicaemia is not warranted.

Antibiotic Susceptibility of Coagulase-negative Staphylococcal Blood Isolates with Special Reference to Adherent, Slime-producing Staphylococcus epidermidis Strains

The epidemiologic relationship between slime-producing coagulase-negative staphylococci and antibiotic resistance was evaluated by analyzing the in vitro susceptibility of 278 blood isolates to 10 different antimicrobial agents. The strain collection consisted of 60 coagulase-negative staphylococcal septicemia isolates, recovered from at least 2 successive blood cultures from 59 septicemia patients and 218 single blood isolates defined as insignificant. When the slime-producing Staphylococcus epidermidis isolates were compared with all non-slime-producing S. epidermidis isolates, the slime-producing isolates exhibited higher MIC50 and/or MIC90 values than the non-slime-producing isolates, and were also more commonly resistant against many of the antimicrobials tested. The association between slime production and resistance against tobramycin, gentamicin and rifampicin was statistically significant (p less than 0.05). A similar finding was observed among the S. epidermidis septicemia isolates when they were analyzed separately from the single (suspected blood contaminant) S. epidermidis isolates. Further characterization of the septicemia isolates revealed that the positive correlation between slime production and antibiotic resistance reflected, to some extent, multiresistance of 1 epidemic slime-producing S. epidermidis strain. No difference in resistance was observed between the slime-producing and non-slime-producing single S. epidermidis blood isolates.

Problems in the investigation of an apparent outbreak of coagulase-negative staphylococcal septicaemia following cardiac surgery

Two hundred and twenty-six hospital staff and patients were investigated for the carriage of gentamicin-resistant coagulase-negative staphylococci (CNS) during an apparent outbreak of infection after cardiac surgery. Of the four index strains from infected wounds, three were indistinguishable. The carriage of similar organisms was widespread, particularly among ITU staff (72%) and patients. Ninety-one of the 296 gentamicin-resistant isolates were further investigated, and of these 33 were indistinguishable from index strains even with the use of specialized techniques. Our experience indicates that in outbreaks of infection caused by gentamicin-resistant CNS, resources should be focused on the interruption of transmission and prevention of introduction of these organisms to susceptible patients.

Septicemia due to coagulase-negative staphylococci in a neonatal intensive care unit: clinical and bacteriological features and contaminated parenteral fluids as a source of sepsis.

During the years 1979 to 1981 we experienced an increasing incidence of septicemia due to coagulase-negative staphylococci in the neonatal intensive care unit (NICU). A detailed analysis was performed for the 1981 NICU population. More than 90% of cases occurred in premature infants of low birth weight (less than 2500 g). All septicemic infants were receiving intravenous therapy and total parenteral nutrition (TPN) solutions had been administered to nearly 80% just before or during the septic episode. A case-control study performed for the 1981 NICU population, which included 26 proved cases of coagulase-negative staphylococcal septicemia and 26 matched controls, did not uncover any differences in underlying diseases or modes of treatment between cases and controls. However, the infusion of contaminated TPN fluids was identified as a significant risk factor. Random bacteriological checks of TPN fluids revealed that nearly 20% of these solutions were contaminated, mainly with coagulase-negative staphylococci. The incidence of staphylococcal septicemia in infants who had received contaminated TPN fluids was 10-fold higher than in infants who had received sterile solutions (P less than 0.0005). The majority of coagulase-negative staphylococci isolated from the blood cultures from the NICU were multiply resistant to antibiotics although all isolates were susceptible to cephalothin. Treatment, consisting of removal or replacement of the intravenous devices and the administration of cephalothin and fresh plasma, was universally successful.

Coagulase-negative staphylococcal septicemia: Experience in a newborn intensive care unit

Coagulase-negative staphylococcal septicemia: Experience in a newborn intensive care unit