Therapeutic experience with netilmicin.

Netilmicin, a new aminoglycoside antibiotic, was used to treat 19 patients with urinary tract infection and 5 with systemic infection. The causal organisms were Escherichia coli (in 2), Klebsiella pneumoniae (in 4), Serratia marcescens (in 12) and Pseudomonas aeruginosa (in 7); 1 patient was infected with two of these organisms. All the isolates of causal organisms except one of Serratia were initially sensitive to netilmicin but many were resistant to other aminoglycosides. Sixteen of the urinary tract infections responded to netilmicin therapy, although relapse occurred in three patients. Two of the three patients with musculoskeletal infection responded to combined therapy with surgery and netilmicin; the other patient responded to the same regimen but with carbenicillin added. Netilmicin cured pneumonia in one patient but failed in the other patient with pneumonia, who had leukemia. Superinfection occurred in five patients with urinary tract infection. Adverse reactions to netilmicin were minor. Netilmicin may prove to be a useful agent, particularly for infections due to multiresistant Klebsiella or Serratia, or when prolonged aminoglycoside therapy is required.     

Microbial ecology and a retrospective assessment of the possibility of predicting an outbreak of suppurative meningitis caused by a Serratia marcescens strain in a hospital for the nursing care of premature infants]

An outbreak of purulent meningitides in a hospital ward for preterm babies, caused by Serratia marcescens strain of serovar 05/13 with multiple resistance, is described. Data on the results of the long-term observation of the ward showed that during three months preceding the outbreak the consecutive spread of the infective strain and its colonization of the intestine of children occurred. At the moment of the outbreak S. marcescens 05/13 was the dominating intestinal microflora in 37% of children in the ward and constituted 30% of the total aerobic flora in the intestine of the examined children. No S. marcescens strains were isolated from the feces and urine of the medical personnel and mothers. The importance of the observation of microflora colonizing newborn infants in the ward for the evaluation and prognostication of the epidemiological situation is discussed.     

Continued Surveillance of Serratia marcescens Infections by Bacteriocin Typing: Investigation of Two Outbreaks of Cross-Infection in an Intensive Care Unit

During an 8.5-month period, 198 additional isolates of Serratia marcescens were typed by bacteriocin sensitivity; 154 isolates were typable and were categorized according to our current system of 54 provisional bacteriocin sensitivity patterns. Two outbreaks of nosocomial infection due to S. marcescens occurred in our intensive care unit, involving two and five patients, respectively. The latter outbreak was caused by a strain of S. marcescens which was not sensitive to any of the 10 bacteriocins normally used. Therefore we developed a supplementary procedure based on bacteriocin production rather than bacteriocin sensitivity. Bacteriocin production was induced with mitomycin C, and the crude lysates were applied to 15 provisional bacteriocin indicator strains. The reverse typing procedure was necessary to determine the spread and ultimate subsidence of this particular outbreak of cross-infection.     

Should we abandon Kielland's forceps?

To assess the risks associated with the use of Kielland''s forceps 2708 consecutive deliveries were studied prospectively and the neonatal outcome related to the mode of delivery. Of the 1191 primigravidas, 279 (23.4%) underwent instrumental delivery, of whom 65 (5.5%) were delivered with Kielland''s forceps. There was no difference in early neonatal outcome (as judged by Apgar scores, intubations, and admission to the special care baby unit) between these babies and those delivered normally or by non-rotational forceps, but a higher proportion of the 127 (10.7%) delivered by emergency caesarean section were compromised. Of the 1517 multigravid patients, only 57 (3.8%) underwent instrumental delivery, 15 (1.0%) by Kielland''s forceps. Among these babies, also, the outcome was no worse than for those delivered normally, but the babies delivered by caesarean section showed a greatly increased incidence of low Apgar scores, intubations, and admission to the special care baby unit. There were no stillbirths or neonatal deaths among babies delivered by Kielland''s forceps, nor were there any cases of severe birth trauma or of obvious neonatal morbidity.     

Pseudomonas aeruginosa colonisation in an intensive therapy unit: role of cross infection and host factors.

Despite the sparsity of Pseudomonas aeruginosa in the environment colonisation and infection with this organism was found at several sites by selective culture in 20 out of 46 patients in an intensive therapy unit. Three patients developed Ps aeruginosa pneumonia. Serial serogrouping and phage typing identified multiple strains in the unit and in the same patient. Rectal carriage occurred in 16 patients but rectal strains did not subsequently appear in tracheal aspirates; strains varied in their affinity for the upper respiratory tract. Colonisation was not directly related to length of stay and was detected in 16 of those colonised within 24 hours of admission. In intubated patients, who were colonised more frequently than those not intubated, upper respiratory tract colonisation correlated strongly with low initial arterial pH values. Personnel were probably responsible for cross infection among patients when the unit was busy. Strain differences and the susceptibility of patients also influenced colonisation and infection. Elimination of major reservoirs of Ps aeruginosa and compliance with procedures to control cross infection remain essential if patients in hospital are to escape colonisation by the organism.     

Rhizosphere colonization and arsenic translocation in sunflower (Helianthus annuus L.) by arsenate reducing Alcaligenes sp. strain Dhal-L

In the present study, six arsenic-resistant strains previously isolated were tested for their plant growth promoting characteristics and heavy metal resistance, in order to choose one model strain as an inoculum for sunflower plants in pot experiments. The aim was to investigate the effect of arsenic-resistant strain on sunflower growth and on arsenic uptake from arsenic contaminated soil. Based on plant growth promoting characteristics and heavy metal resistance, Alcaligenes sp. strain Dhal-L was chosen as an inoculum. Beside the ability to reduce arsenate to arsenite via an Ars operon, the strain exhibited 1-amino-cyclopropane-1-carboxylic acid deaminase activity and it was also able to produce siderophore and indole acetic acid. Pot experiments were conducted with an agricultural soil contaminated with arsenic (214 mg kg^?1). A real time PCR method was set up based on the quantification of ACR3(2) type of arsenite efflux pump carried by Alcaligenes sp. strain Dhal-L, in order to monitor presence and colonisation of the strain in the bulk and rhizospheric soil. As a result of strain inoculation, arsenic uptake by plants was increased by 53 %, whereas ACR3(2) gene copy number in rhizospheric soil was 100 times higher in inoculated than in control pots, indicating the colonisation of strain. The results indicated that the presence of arsenate reducing strains in the rhizosphere of sunflower influences arsenic mobilization and promotes arsenic uptake by plant.     

Screening for resistance to Aspergillus flavus and aflatoxin production in groundnut

All the varieties, advanced breeding lines, germplasm lines, and wild species used in the experiments differed significantly for their ability to allow invasion and aflatoxin production by an aflatoxigenicAspergillus flavus strain. Infection and colonisation were strongly correlated (r = 0.82), while there was no relation between infection and aflatoxin content or colonisation and aflatoxin content (r = 0.15). The varieties ICGS11 and S 206 supported less infection and colonisation (range 35 to 40%). Lowest aflatoxin content was recorded in Chitra (3,200 ppb), while it was highest in Kaushal (38,250 ppb). A cross derivative of GAUG1 × NC Ac 17133 R F showed lowest infection and colonisation (86,3 and 25,28%, respectively), and also supported moderate aflatoxin production (4,000 ppb). Among germplasm lines spancross supported lowest aflatoxin production (2,026 ppb) while both the wild species vz. ICG 8127 and ICG 8128 were highly susceptible to infection, colonisation, and aflatoxin production.     

Root colonisation of Pseudomonas aeruginosa strain UPMP3 and induction of defence‐related genes in oil palm (Elaeis guineensis)

Pseudomonas aeruginosa strain UPMP3 labelled with β‐glucuronidase (gusA) and green fluorescent protein (gfp) by electrotransformation yielded ca 1 × 10⁷ transformants µg^?1 DNA. The data obtained from the dilution plate count showed that over 28 days both epiphytic and endophytic populations of P. aeruginosa strain UPMP3 increased from 5.76 log₁₀ [colony forming unit (CFU) + 1] g^?1 fresh weight (FW) to 8.19 log₁₀ (CFU + 1) g^?1 FW and 4.10 log₁₀ (CFU + 1) g^?1 FW to 6.23 (CFU + 1) g^?1 FW, respectively. Confocal laser scanning microscopic analysis of oil palm roots treated with gusA:gfp‐tagged P. aeruginosa strain UPMP3 showed intense root colonisation over the sampling period. The root surface colonisation by P. aeruginosa strain UPMP3 was followed by a second stage, characterised by cortical infection, and a third stage, which involves xylem ingression. The colonisation of oil palm roots by the gusA:gfp‐tagged strain was concentrated on root areas potentially rich in nutrients such as the elongation zones, ridges between epidermal cells and points of secondary adventitious root emergence. Different expression levels of defence‐related genes, namely, chitinase and β‐1,3‐glucanase in the strain UPMP3–host interaction recorded over 28 days, suggested the potential role of P. aeruginosa strain UPMP3 in triggering the defence mechanism in oil palm. This is the first report on root colonisation and upregulation of defence‐related genes on oil palm roots by P. aeruginosa strain UPMP3 and shows the potential of this strain to be used as a biocontrol agent in oil palm.     

Outbreak of coagulase negative staphylococcus highly resistant to ciprofloxacin in a leukaemia unit.

OBJECTIVE--To define an outbreak of bacteraemia due to coagulase negative staphylococci highly resistant to ciprofloxacin in a leukaemia unit, investigate the source and mode of spread of the outbreak strain, and assess control measures. DESIGN--The outbreak strain was characterised by five different typing methods. Surveillance of patients, staff, and environment was carried out during the outbreak and five months after control measures were introduced. SETTING--A unit with 10 beds for adults with leukaemia and patients receiving bone marrow transplants. The outbreak occurred during a trial of ciprofloxacin for empirical treatment of neutropenic fevers. INTERVENTIONS--Ciprofloxacin was withdrawn from use in the unit and daily bathing with chlorhexidine gluconate solution started. Main outcome measure--The absence of bacteraemia due to the outbreak strain for five months after control measures. RESULTS--During the study 49 patients developed 21 episodes of bacteraemia due to the outbreak strain, which was ciprofloxacin resistant (minimum inhibitory concentration greater than or equal to 128 mg/l), susceptible to phage 155 A9C, and SII biotype and had characteristic immunoblot and DNA fingerprint features. There was a high amount of colonisation of patients but not staff with this strain, which was also wide spread in the environment. The control measures led to rapid resolution of the outbreak and disappearance of the strain from the unit. CONCLUSIONS--In areas where coagulase negative staphylococcal infections are common doctors must be aware of the possibility of cross infection with single strain, and the availability of more discriminatory methods of typing will facilitate the identification and control of such episodes.     

Parents' perceptions of taking babies' rectal temperature.

OBJECTIVE--To explore the attitudes of parents to measuring their babies'' rectal temperature. DESIGN--Qualitative study using unstructured interviews of parents given "Baby Check," a scoring system designed to assess severity of illness in babies that includes measurement of rectal temperature. SETTING--One inner city general practice in Newcastle upon Tyne. SUBJECTS--42 parents of 34 babies under 6 months old. RESULTS--Parents were reluctant to measure rectal temperature in their babies; 37 parents spontaneously raised concerns. Fifteen did not undertake measurement, 16 did so once only, and 11 did so more than once. Parents'' concerns included a fear of hurting their child, anxieties about sexual intimacy and abuse, difficulty in comforting their child, and concern for their child''s feelings. Most (33) substituted axillary measurement. CONCLUSIONS--Parents'' preference for the axillary method of measuring temperature and resistance to using a rectal method in their children was based on several concerns. If parents are to be encouraged to use the rectal method of measuring temperature in sick babies any benefits must be set against the generation of considerable parental anxiety and the resources that would be necessary to negotiate with parents and change their views.     

Isolation of Serratia marcescens in the midgut of Rhodnius prolixus: impact on the establishment of the parasite Trypanosoma cruzi in the vector

The effects of resident bacteria in the stomach of 5th-instar larvae of Rhodnius prolixus on the erythrocyte lysis and Trypanosoma cruzi infection were studied. The bacteria population increased approximately 10,000-fold after feeding. Hemolysis rose to approximately 28% within 24h postfeeding and then linearly grew until day 4 attaining almost 100%. The number of surviving Y strain of T. cruzi in the stomach declined drastically, while the infection with Dm28c clone was maintained stable. Five days after feeding, few different types of bacterial colonies were obtained when stomach content suspensions were spread onto BHI agar plates. The hemolytic bacteria were isolated and identified as Serratia marcescens biotype A1a (referenced as RPH), which produces the pigment prodigiosin. In vitro experiments, comparing incubations of RPH with S. marcescens SM365, a prodigiosin pigment producer, and S. marcescens DB11, a nonpigment variant, as a control, with erythrocytes and T. cruzi demonstrated that: (i) at 30 degrees C, SM365 and RPH diminished the populations of Y strain, but not DM28c clone, and DB11 was unable to lyse both T. cruzi strains; (ii) at 0 degrees C, SM263 and RPH killed the flagellates, but DB11 did not; and (iii) all three strains of S. marcescens were able to lyse erythrocytes. These results suggest that S. marcescens trypanolytic activity from the SM365 and RPH strains is distinct from the hemolytic activity and that prodigiosin is an important factor for the trypanolytic action of the bacteria.     

Kielland's forceps: association with neonatal morbidity and mortality.

The incidence of certain neonatal complications associated with the use of Kielland''s forceps was analyzed retrospectively in liveborn singleton babies delivered at this hospital between January and December 1976. The neonatal mortality rate attributable to use of the forceps was 34.9 per 1000. The incidences of delayed onset of respiration (17.4%), birth trauma (15.1%), and abnormal neurological behaviour--namely, apathy or irritability or both--(23.3%) significantly exceeded those in a matched group of babies born spontaneously. Fetal asphyxia played a major part in the aetiology of neonatal complications. Babies on whom Kielland''s forceps were used, however, had a significantly greater incidence of abnormal neurological behaviour even in the absence of fetal asphyxia (14.3%), and in all of these babies the abnormal behaviour was transient and did not necessitate admission to the special-care baby unit. Neither maternal height nor the infant''s birth weight or occipitofrontal head circumference influenced the occurrence of neonatal complications. The results also suggest that neither the speed of cervical dilatation nor the timing of engagement of the fetal head is of help in predicting the occurrence of neonatal complications after the use of Kielland''s forceps.     

Novel tetracycline resistance determinant isolated from an environmental strain of Serratia marcescens

Resistances to tetracycline and mercury were identified in an environmental strain of Serratia marcescens isolated from a stream highly contaminated with heavy metals. As a step toward addressing the mechanisms of coselection of heavy metal and antibiotic resistances, the tetracycline resistance determinant was cloned in Escherichia coli. Within the cloned 13-kb segment, the tetracycline resistance locus was localized by deletion analysis and transposon mutagenesis. DNA sequence analysis of an 8.0-kb region revealed a novel gene [tetA(41)] that was predicted to encode a tetracycline efflux pump. Phylogenetic analysis showed that the TetA(41) protein was most closely related to the Tet(39) efflux protein of Acinetobacter spp. yet had less than 80% amino acid identity with known tetracycline efflux pumps. Adjacent to the tetA(41) gene was a divergently transcribed gene [tetR(41)] predicted to encode a tetracycline-responsive repressor protein. The tetA(41)-tetR(41) intergenic region contained putative operators for TetR(41) binding. The tetA(41) and tetR(41) promoters were analyzed using lacZ fusions, which showed that the expression of both the tetA(41) and tetR(41) genes exhibited TetR(41)-dependent regulation by subinhibitory concentrations of tetracycline. The apparent lack of plasmids in this S. marcescens strain, as well as the presence of metabolic genes adjacent to the tetracycline resistance locus, suggested that the genes were located on the S. marcescens chromosome and may have been acquired by transduction. The cloned Tet 41 determinant did not confer mercury resistance to E. coli, confirming that Tet 41 is a tetracycline-specific efflux pump rather than a multidrug transporter.     

Virologic and serologic studies on an outbreak of echovirus type 11 infection in a hospital maternity unit.

An outbreak of echovirus type 11 (E-11) infection occurred among newborn babies in a hospital maternity unit in the summer of 1971. The results of studies are as follows: 1) Forty-one of 188 infants developed febrile illness with stomatitis during one and a half months from July to September. E-11 was isolated from stool specimens of 14 infants and two throat swabs. Antibody response to the virus was shown in all the 19 cases examined. Some of their mothers were suffering from subclinical infection. 2) The isolates were identified as a variant of E-11 which is not neutralized with antiserum against prototype E-11. Antiserum against the current virus neutralized both current and prototype viruses. 3) Sucrose gradient centrifugation of sera from infants revealed that the neutralizing antibody activity resided more predominantly in 19S than in 7S fractions. These antibodies reacted more specifically with the current strain than with the prototype Gregory strain.     

Nosocomial transmission of group B streptococci.

The acquisition of group B streptococci by babies in a special-care baby unit and two postnatal wards was investigated over a six-month period using serology and phage typing. Sixty-three culture-positive babies were identified in the postnatal wards, one-third of whom had been born to mothers who were not carrying the organism in the genital tract or anorectal area during labour. A non-maternal source was identified for 14 of these 21 infants: either colonised mothers and babies in the same ward or, on one occasion, a member of the hospital staff. In the special-care baby unit, however, only one instance of nosocomial acquisition of group B streptococci was recorded despite a high prevalence of colonisation in the staff on the unit and the presence of heavily colonised babies. The results of this survey suggest that although sepsis caused by group B streptococci may be the result of nosocomial transmission, this may be prevented by careful attention to hygiene.     

儿童重症监护病房医院感染暴发白色念珠菌血流感染4例分析

摘要 目的：探讨儿童重症监护病房白色念珠菌血流感染暴发的临床表现、危险因素、控制措施等,为预防和控制院内白色念珠菌血流感染暴发提供科学依据。方法：以2018年7月我院儿童重症监护病房发生的4例白色念珠菌血流感染暴发患儿为研究对象,分析患儿临床情况、临床特征、危险因素、暴发原因以及采取的预防控制措施。结果：4例医院感染暴发白色念珠菌血流感染患儿均存在基础疾病、有机械通气史、存在中心静脉或动脉置管、静脉或动脉置管前后均使用碘伏消毒、曾使用广谱抗生素、输血制品,白色念珠菌血流感染后最突出的临床表现均是发热。药敏方面,医院感染暴发的4例白色念珠菌感染患儿对唑类及5-氟胞嘧啶均耐药,但对两性霉素B均敏感。经拔除血管置管、减少或者避免广谱抗菌药的应用,根据药敏使用卡泊芬净及两性霉素B抗真菌等积极治疗,1例患儿放弃治疗后死亡,3例患儿顺利出院。通过Fisher确切概率法分析可知,留置中心静脉或动脉置管是儿童重症监护病房发生医院感染暴发白色念珠菌血流感染的危险因素（P<0.05）。结论：留置中心静脉或动脉置管是儿童重症监护病房发生医院感染暴发白色念珠菌血流感染的危险因素,医院感染暴发白色念珠菌血流感染患儿最突出的临床表现是发热,唑类及5-氟胞嘧啶耐药的患儿使用卡泊芬净及两性霉素B可能获得较好的治疗效果。     

Postantibiotic effects of gentamicin and netilmicin onSerratia marcescens: Effects on hydrophobicity and motility

The impact of postantibiotic effect (PAE) of aminoglycosides (gentamicin, netilmicin) on cell-surface hydrophobicity and motility of a clinical isolateSerratia marcescens was evaluated. For the induction of PAE 2× and 4×MIC concentrations of both antibiotics were used. Gentamicin and netilmicin induced a PAE of similar duration after 2×MIC concentration (2.7 and 2.8 h, respectively). Both aminoglycosides demonstrated concentration-dependent PAE. At a concentration of 4×MIC they produced PAEs of 5.9 and 8.2h, respectively. The evaluation of hydrophobic properties ofS. marcescens after affecting PAE showed that both aminoglycosides inhibited adherence to xylene. This inhibition was also concentration-dependent. More expressive, was netilmicin which inhibited the adhesion by 70.5% at 2×MIC and by 85.2% at 4×MIC. Netilmicin inhibited also the adhesion to nitrocellulose filter by 34.7% at 4×MIC. Exposure of the bacterial cells to suprainhibitory concentrations of both aminoglycosides resulted only in moderate inhibition of motility of strain tested compared to the unexposed cells.     

Resistance of Serratia marcescens to an etbylene oxide-methyl bromide mixture and the possibility of using it to control the effectiveness of disinfectant measures]

The authors studied the Serratia marcescens (strain No. 851) resistance to the ok?bm mixture by the method of test objects in comparison with the vaccine virus (strain B-51) at a temperature of 20, 30, and 40 degrees C. Resistance of the mentioned bacteria to the ok?bm mixture proved to be somewhat greater than that of the vaccine virus at 20 and 30 degrees C, whereas at 40 degrees C their resistance was found to be practically identical. This permits to use Serratia marcescens to control the efficacy of gaseous sterilization of materials.     

Serratia marcescens infection in a swallow-tailed hummingbird

A swallow-tailed hummingbird (Eupetomena macroura) was presented with a history of prostration and inability to fly. After a 2-day hospitalization, the bird died and necropsy findings included diffuse hyperemia of the small intestine serosal and mucosal surfaces and the presence of a small quantity of clear ascitic fluid in the coelomic cavity. Intestinal contents and cardiac blood were collected for microbiologic exams yielding pure cultures of a pigmented strain of Serratia marcescens. This strain was susceptible to gentamicin, enrofloxacin, streptomycin, trimethoprim, and sulfamethoxazole and had intermediate susceptibility to chloramphenicol and resistance to cephalotin. The source of the infection could not be ascertained, but possible contamination of hummingbird feeders could be involved, because the infection seemed to originate from the digestive tract.     

Combinations of Clavulanic Acid and other β-lactam Antibiotics against Strains of Pseudomonas aeruginosa, Serratia marcescens and other Bacteria

Combinations of clavulanic acid, a new β-lactamase inhibitor, with five cephalosporins and one cephamycin were tested against cell-free β-lactamases obtained from Serratia marcescens, Pseudomonas aeruginosa and an Enterobacter strain, 265A. Cefotaxime was the most resistant antibiotic and cephalothin the most sensitive antibiotic to β-lactamases. Low concentrations of clavulanic acid gave some protection against the Serratia and Pseudomonas enzymes. The most active source of β-lactamase was the 265A strain, against which only cefotaxime was highly resistant. Clavulanic acid had only a slight inhibitory effect on this enzyme, which was confirmed by an agar method, and potentiated slightly the activity of cephalothin and cefoxitin against two β-lactamase producing strains of Staphylococcus aureus. Lysis by cephalothin of one strain of S. marcescens was potentiated in the presence of clavulanic acid.