Bacteriophage Typing Research Articles

Infection with netilmicin resistant Serratia marcescens in a special care baby unit.

An outbreak of colonisation and infection with a netilmicin resistant strain of Serratia marcescens occurred in a special care baby unit. S marcescens was isolated from a total of 13 babies; significant infection occurred in five, of whom two died. Epidemiological investigation failed to detect a common source but gastrointestinal colonisation of babies formed a prolonged and possibly important reservoir for infection. Containment proved difficult until the unit was closed to new admissions, and even then spread to a temporary unit ensued. O Serotyping and bacteriophage typing disclosed a single epidemic strain. This produced an aminoglycoside acetylating enzyme (AAC(6')) conferring resistance to netilmicin and tobramycin and moderate resistance to amikacin. Use of gentamicin resulted in the isolation of serratia with increased resistance to all aminoglycosides, and, similarly, increased resistance to third generation cephalosporins emerged with their use.

Production of a bacteriolysin by a hemolytic Escherichia coli strain.

Nonhemolytic Escherichia coli were outnumbered by hemolytic E. coli within 24 h after being inoculated in a mixed culture at an initial ratio of 200 nonhemolytic to 1 hemolytic organism. The hemolytic strain was found to produce a cell-free, filterable substance which causes lysis of nonhemolytic E. coli B when grown in liquid cultures but not when grown on agar plates. The bacteriolysin is inactivated by boiling, by freezing and thawing, and by incubation with trypsin. The inability to inhibit growth on an agar plate, dependence on cell concentration for its effect, lysis of the sensitive cells, and appearance of phage particles in the cell lysates suggest that this substance is not like colicins or microcins previously described. After lysis of E. coli B, bacteriophage particles were visible in transmission electron micrographs of material pelleted by ultracentrifugation. However, no bacteriophage were observed in pellets from the bacteriolysin-containing supernatants before lysis of E. coli B. Failure to find bacteriophage in these preparations, and the fact that some bacteriolysin activity remains in the supernatant solution after centrifugation at 150,000 X g for 6.5 h, indicate that the bacteriolysin is not itself a bacteriophage. Exposure of E. coli B to UV light and mitomycin C did not induce production of a temperate phage. The properties of this system, in which a cell-free substance produced by one strain of bacteria causes lysis of another strain, appear to differ from those of the various types of bacteriocins and bacteriophages described to date.

Staphylococcus in toxic shock syndrome and other surgical infections. Development of new bacteriophages.

Recent studies of Staphylococcus aureus isolates from patients with toxic shock syndrome (TSS) have shown the dominance of phage type 29/52 with the capacity to produce pyrogenic exotoxin C and enterotoxin F. They also showed that 29% of the isolates were nontypable and 90% of them had similar toxigenic properties. The existence of unknown and important phages in this disease was postulated. Five new phages were then developed and used for typing three groups of staphylococcal isolates: 236 from patients with TSS, 67 from patients without TSS, and 159 from patients with infected burns. Results showed a high correlation between the lytic action of the new phages and the 29/52 phages, and an additional typing capability in 35% of the previously nontypable TSS isolates, emphasizing further the potential of bacteriophage typing of S aureus in these infections.

Bacteriophage typing of strains of Mycobacterium tuberculosis from Nepal

One hundred strains of Mycobacterium tuberculosis isolated from cases of pulmonary tuberculosis in Nepalese villagers were typed with the World Health Organization set of bacteriophages. The number of strains in the 3 major phage types A, I, and B were 19, 53, and 28 respectively. This distribution is significantly different from those described in other geographical regions. In particular there was a relatively low incidence of type A strains and, in common with South India, there was a high proportion of type I strains. All the strains in this study were resistant to 5-Furan-2 carbonic acid hydrazine and 34 were highly resistant to isoniazid. Representative strains of the 3 phage types, including 4 isoniazid-resistant type I strains, did not differ in their virulence in the guinea pig; thus the type I strains found in Nepal may not be of the same origin as those of this phage type from India which are usually attenuated in the guinea pig. This study provides further evidence for the existence of geographical differences in the types of tubercle bacilli.

Bacteriophage types of Salmonella typhi in the United States from 1974 through 1981.

From 1974 through 1981, 4,089 isolates of Salmonella typhi were phage typed at the Centers for Disease Control and nine regional laboratories in the United States. The most prevalent types were degraded Vi (27%), E1 (20.6%), A (9.8%), C1 (5.7%), untypable Vi (3.5%), W form (3.5%), D1 (3.4%), B3 (3.4%), and F1 (2.4%). There were less than 2% of each of the remaining types. The distribution of phage types for this time period was similar to that seen in the periods 1966-1969 and 1970-1973, except that phage type B3 was one of the 10 most prevalent types in 1974-1981 but was not seen in 1966-1973. Phage typing is presently the most valuable laboratory tool for differentiation of strains of S. typhi in epidemiological studies.

Staphylococcus aureus isolated from poultry in Australia II. Epidemiology of strains associated with tenosynovitis

Bacteriophage typing of Staphylococcus aureus from different outbreaks of tenosynovitis in broiler breeder replacement chickens showed that, although a mixture of phage types was present on affected farms, there was a predominant phage type isolated from lesions of affected chickens. The predominant phage type isolated from chickens in different outbreaks was variable. The source of S. aureus associated with tenosynovitis appeared to be a resident population present on the skin.

Outbreaks of hospital infection in southwest England caused by gentamicin-resistant Serratia marcescens

Five geographically separate outbreaks of hospital acquired infection caused by gentamicin-resistant strains of Serratia marcescens occurred in the period October 1977 to January 1980 in southwest England. The patients affected were in wards for general or urological surgery, or in neurosurgical, cardiothoracic or general intensive therapy units. Asymptomatic colonization was more common than symptomatic infection, although deaths and serious infections occurred. Control of spread of the bacteria proved difficult. Most strains were resistant to many currently available antibiotics besides gentamicin; only one strain became resistant to amikacin. Representative isolates where characterized by O serotype, bacteriophage type, antibiotic sensitivity pattern, production of β-lactamases and amino-glycoside-aminocyclitol (ACAG)-modifying enzymes, and plasmid visualization. Plasmid studies provided information that complemented conventional typing methods in determining epidemiological relationships among the outbreaks.

Methicillin-resistant Staphylococcus aureus: experience in a general hospital over four years.

From 1977 to 1981, 317 patients in a large general hospital became infected with methicillin- and gentamicin-resistant Staphylococcus aureus. The epidemic strain was characterized as bacteriophage type D11/83A/85, resistant to methicillin, cephalosporins and aminoglycosides, and contained a 24 megadalton plasmid which mediated gentamicin resistance. Spread within the hospital followed introduction of this organism into the general surgical and burn services and resulted from cross infection between patients. These services remained a reservoir of infection throughout the four-year period. Only 2% of hospital personnel carried methicillin-resistant S. aureus in their anterior nares, and only one of them was shown to be a long-term carrier. During the epidemic, there was no overall increase in serious staphylococcal infections, as reflected in bacteremias. As methicillin-resistant S. aureus increased, there was a reciprocal decrease in methicillin-sensitive S. aureus. Later, as methicillin-resistant S. aureus bacteremias decreased, methicillin-sensitive S. aureus bacteremias increased. Attempts to control the spread of the organism by containing infected patients on an isolation ward, or by placing all such infected patients in strict isolation, decreased the frequency of infections, but did not eliminate the organism. In 1980, the burn service was separated from the surgical service and moved into a new burn unit. Also, the five-bed rooms in the hospital were being converted to two-bed rooms. With only routine isolation precautions, the epidemic resolved over the next year, although the epidemic strain persists in the hospital.

Bacteriophage types of Mycobacterium tuberculosis in the United States.

Strains of Mycobacterium tuberculosis from various geographic areas within the continental United States were typed according to their susceptibility to 4 mycobacteriophages. Of 462 wild isolates studied, 34% were phage type 1 (previously designated A0), 42% were type 2 (A1), 2.6% were type 5 (A4), 13% were type 7 (A6), and 20.1% were type 8 (B). Distribution of types was essentially unaffected by geographic location, sex, age, or ethnic origin of the patient or by resistance of the isolate to antituberculosis drugs. Major types were further divided by susceptibility of the strains to lysis by 8 auxiliary phages, 2 of which were phages newly evaluated in this study. A new numbering system is proposed for designating major phage types of M. tuberculosis.

Pseudomonas aeruginosa skin infections in persons using a whirlpool in Vermont

Four guests at a ski resort in Vermont reported contracting a characteristic papular, pustular, or vesicular rash after using the resort's whirlpool. Pseudomonas aeruginosa serotype 1, bacteriophage type 86, was isolated from a pustule on one patient, water within the whirlpool, and the whirlpool diatomaceous earth filter. This appears to be the first outbreak of dermatitis associated with P. aeruginosa serotype 1. Previous reports of whirlpool-associated dermatitis outbreaks have identified serotype 9 and 11 isolates of P aeruginosa as the causative agents.

New bacteriophage typing system for Yersinia enterocolitica, Yersinia kristensenii, Yersinia frederiksenii, and Yersinia intermedia: correlation with serotyping, biotyping, and antibiotic susceptibility.

New bacteriophage typing system for Yersinia enterocolitica, Yersinia kristensenii, Yersinia frederiksenii, and Yersinia intermedia: correlation with serotyping, biotyping, and antibiotic susceptibility.

Serotyping and bacteriophage typing of human and bovine group-B streptococci.

Summary. Serotypes and phage types of group-B streptococci isolated from healthy and diseased human subjects and from cattle in different parts of Norway have been compared. The phage set used was found to be suitable for the study of strains from cows as well as from man.

Quantitative and Qualitative Studies of Aeromonas salmonicida Bacteriophage

A comprehensive bacteriophage typing scheme for Aeromonas salmonicida, the causal agent of furunculosis in fish, is described. It distinguishes 27 bacterial groups based on sensitivity patterns to 18 bacteriophage isolates. In addition, the sensitivity patterns are shown to reflect the morphological characteristics of the host bacterium. The ‘rough’,‘smooth’ and ‘G-phase’ forms possess different quantities of lipopolysaccharide in the cell wall and this influences bacteriophage attachment. The problems related to these morphological variations are discussed.

Transmission of group B streptococci. Traced by use of multiple epidemiologic markers.

During a three-week period, septicemia caused by group B Streptococcus, serotype III, developed in four infants born at a community hospital. The first infant had early-onset disease; late-onset disease that appeared, from epidemiologic data, to be nosocomial developed in the other three infants. Bacteriophage typing and antimicrobial susceptibility testing confirmed the relatedness of the isolates. A prospective study designed to differentiate between vertical and nosocomial transmission of group B Streptococcus showed that of 82 infants, 21 (26%) were culture-positive during their hospitalization, and nine of these infants (43%) had been culture-negative at birth. Although serotype III strains were recovered from four of nine infants with apparently nosocomial acquisition, none of the isolates displayed an antibiogram or bacteriophage type similar to that of the isolates involved in the recent cluster. Bacteriophage typing and antimicrobial susceptibility testing in addition to the use of serotyping may be helpful in epidemiologic studies of group B Streptococcus.

466 RIFAMPIN IN ERADICATION OF METHICILLIN/GENTAMICINRESISTANT S. AUREUS FROM AN NICU

An outbreak of infections caused by methicillin- and gentamicin-resistant Staphylococcus aureus (MGRS) occurred in the Children's Memorial Hospital NICU in 1979-80. MGRS was isolated from 44 patients in a 21-month period. Infections included bacteremia (6), ventriculitis (3), osteomyelitis (3), otitis media (2) and surgical wounds (6). Nasal carriage of MGRS of bacteriophage type 29/52 was present in 4/56 (7%) of personnel and in up to 75% of patients. Traditional infection control measures failed to interrupt MGRS transmission; intranasal bacitracin + oral rifampin eradicated nasal carriage in 4/4 adults. Bacitracin alone or treatment of infections with a single antibiotic to which MGRS was sensitive (vancomycin or chloramphenicol) failed to eradicate carriage in 6/6 and 10/11 trials, respectively. Bacitracin + rifampin terminated nasal carriage in 3/6 infants. Treatment with bacitracin + rifampin + IV vancomycin or oral erythromycin terminated carriage in all of 8 patients. This regimen was superior to bacitracin alone (p< 0.001), vancomycin or chloramphenicol alone (p <0.001), and bacitracin + rifampin (p=0.06). All patients treated with the three-drug regimen have remained MGRS-negative for up to 10 months. We conclude that therapy with bacitracin, rifampin, and another antibiotic to which the organism is sensitive is effective in eradicating neonatal MGRS carriage.

Nosocomial transmission of bacteriophage type 7/11/12 group B streptococci in a special care nursery.

Two premature infants in a special care nursery acquired late-onset group B streptococcal (GBS) sepsis within a 24-hour period. The infecting strains were serotype III organisms with bacteriophage type 7/11/12. Cultures of the mothers of the two affected infants were negative for GBS, implying nosocomial acquisition of infection. Although 32% of nursery personnel had mucosal carriage of GBS, none of the seven isolates of GBS type III was the same bacteriophage type as the two infecting strains. Of the other infants hospitalized in the nursery, five were asymptomatically colonized with GBS. These infants were in bassinets adjacent to the affected infants; all five of their isolates were identical to the two infecting strains. We conclude that infant-to-infant transmission may result in nosocomial late-onset GBS septicemia.

Gentamicin- and clindamycin-resistant Staphylococcus aureus

From 1975 through 1978 isolates from 21 of 230 (9%) Staphylococcus aureus bacteremias were resistant to gentamicin and clindamycin. Gentamicin- and clindamycin-resistant S aureus (GCRS) accounted for 23% of all S aureus isolates from 1977 compared with 2 to 6% in the two years immediately preceding, and the year following 1977. When compared with patients with gentamicin- and clindamycin-sensitive S 3£y/-eus(GCSS)from 1977, GCRS were more often isolated from patients who acquired their infections in the hospital, particularly in the intensive care unit. A significant association existed between prior or concurrent therapy with gentamicin and/or clindamycin and the isolation of GCRS. Infection with GCRS was associated with a 73% mortality rate versus 28% with GCSS. GCRS were susceptible to oxacillin, cephalothin, tetracycline, and vancomycin. GCRS were resistant to kanamycin and tobramycin but were susceptible to amikacin (median MIC of GCRS, 4.0 μg/ml). Multiple bacteriophage types of S aureus were involved, and resistance appeared to be plasmid-mediated. A survey of antibiotic usage showed that in comparison to January 1977, amikacin usage increased and gentamicin usage decreased in March 1979. Because of the popularity of the combination of clindamycin and gentamicin for therapy of life-threatening infections, clinicians should be aware of potential gentamicin- and clindamycin-resistance in S aureus.

Bacteriophage typing scheme for Salmonella infantis.

A bacteriophage typing system is described for Salmonella infantis. Nine phages were selected, of which three were isolated from sewage and six from human feces. All except 7 of the 546 strains collected between 1974 and 1978 could be classified into 23 different phage types. The five most common phage types comprised 26, 13, 9, 9, and 9% of all strains, respectively. Strains from humans, animals, food, and water isolated during nine episodes, or from given patients at different intervals of time, belonged to the same phage type.

Bacteriophage typing of coagulase-negative staphylococci

Cultures comprising the 10 species of coagulase-negative staphylococci proposed by Kloos and Schleifer (J. Clin. Microbiol. 1:82--88, 1975) were typed with bacteriophages isolated from Staphylococcus epidermidis. Although only 10.5% were typable, 50% of those identified as S. epidermidis were typed. Cultures from patients with middle ear infections were also classified by this system and phage typed.

Bacteriophage typing of Staphylococcus aureus isolated from dogs in Japan.

[in Japanese]