一株新型旱獭源性宽谱大肠杆菌噬菌体的分离鉴定及基因组分析

[目的]分离喜马拉雅旱獭肠内容物样本中的噬菌体,并研究其生物学特性和基因组特征。[方法]以大肠杆菌为宿主菌,利用双层琼脂平板法从喜马拉雅旱獭肠内容物样本中分离噬菌体;用透射电镜观察形态特征;测定其最佳感染复数、一步生长曲线、酸碱耐受度及宿主裂解谱等生物学特性,并进行全基因组测序。[结果]从喜马拉雅旱獭肠内容物样本中分离得到一株裂解性大肠杆菌噬菌体,命名为vB_EcoM_TH18,其噬菌斑呈无晕环的透亮圆形,透射电镜观察发现该噬菌体头部直径为(90±5) nm,尾部长度为(115±5) nm;最佳感染复数为1;一步生长曲线显示其潜伏期为10 min,110 min后进入平台期,平均裂解量为15 PFU/mL;在pH 4.5-9.5的范围内具有稳定活性;可裂解多种致病型和血清型大肠杆菌和宋内志贺氏菌,无法裂解沙门氏菌、屎肠球菌、金黄色葡萄球菌、肺炎克雷伯杆菌及鲍曼不动杆菌;基因组测序结果表明,其基因组长度为133 882 bp,GC含量为39.95%。基因组共注释到210个编码序列(CDS)和13个tRNAs,不含毒力基因及耐药基因。BLASTn比对结果表明该基因组与Avunavirus属噬菌体Av-05同源性为95.17%。基于噬菌体全基因组、主要衣壳蛋白和终止酶大亚基分别构建系统进化树,结果表明vB_EcoM_TH18是一株肌尾噬菌体科(Myoviridae) Avunavirus属的新型噬菌体。[结论]从喜马拉雅旱獭肠内容物中成功分离并鉴定了一株新型宽谱大肠杆菌噬菌体vB_EcoM_TH18,可裂解多种致病型和血清型的大肠杆菌及宋内志贺菌。     

Isolation of lytic bacteriophage against Vibrio harveyi

Aims: The isolation of lytic bacteriophage of Vibrio harveyi with potential for phage therapy of bacterial pathogens of phyllosoma larvae from the tropical rock lobster Panulirus ornatus. Methods and Results: Water samples from discharge channels and grow‐out ponds of a prawn farm in northeastern Australia were enriched for 24 h in a broth containing four V. harveyi strains. The bacteriophage‐enriched filtrates were spotted onto bacterial lawns demonstrating that the bacteriophage host range for the samples included strains of V. harveyi, Vibrio campbellii, Vibrio rotiferianus, Vibrio parahaemolyticus and Vibrio proteolyticus. Bacteriophage were isolated from eight enriched samples through triple plaque purification. The host range of purified phage included V. harveyi, V. campbellii, V. rotiferianus and V. parahaemolyticus. Transmission electron microscope examination revealed that six purified phage belonged to the family Siphoviridae, whilst two belonged to the family Myoviridae. The Myoviridae appeared to induce bacteriocin production in a limited number of host bacterial strains, suggesting that they were lysogenic rather than lytic. A purified Siphoviridae phage could delay the entry of a broth culture of V. harveyi strain 12 into exponential growth, but could not prevent the overall growth of the bacterial strain. Conclusions: Bacteriophage with lytic activity against V. harveyi were isolated from prawn farm samples. Purified phage of the family Siphoviridae had a clear lytic ability and no apparent transducing properties, indicating they are appropriate for phage therapy. Phage resistance is potentially a major constraint to the use of phage therapy in aquaculture as bacteria are not completely eliminated. Significance and Impact of the Study: Phage therapy is emerging as a potential antibacterial agent that can be used to control pathogenic bacteria in aquaculture systems. The development of phage therapy for aquaculture requires initial isolation and determination of the bacteriophage host range, with subsequent creation of suitable phage cocktails.     

A guard-killer phage cocktail effectively lyses the host and inhibits the development of phage-resistant strains of Escherichia coli

In recent years, after the emergence of a large number of multidrug-resistant bacteria, phages and phage-associated products for the prevention and control of bacterial disease have revealed prominent advantages as compared with antibiotics. However, bacteria are susceptible to becoming phage-resistant, thus severely limiting the application of phage therapy. In this study, Escherichia coli cells were incubated with lytic bacteriophages to obtain mutants that were resistant to the lytic phages. Then, bacteriophages against the phage-resistant variants were isolated and subsequently mixed with the original lytic phage to prepare a novel phage cocktail for bactericidal use. The data showed that our phage cocktail not only had notable bactericidal effects, including a widened host range and rapid lysis, but also decreased the generation and mutation frequency of phage-resistant strains in vitro. In addition, we tested our cocktail in a murine bacteremia model. The results suggested that compared with the single phage, fewer phage-resistant bacteria appeared during the treatment of phage cocktail, thus prolonging the usable time of the phage cocktail and improving its therapeutic effect in phage applications. Importantly, our preparation method of phage cocktail was proved to be generalizable. Because the bacteriophage against the phage-resistant strain is an ideal guard that promptly attacks potential phage resistance, this guard-killer dual-function phage cocktail provides a novel strategy for phage therapy that allows the natural ecology to be sustained.

     

Bacteriophage isolated from non-target bacteria demonstrates broad host range infectivity against multidrug-resistant bacteria

Antibiotic resistance represents a global health challenge. The emergence of multidrug-resistant (MDR) bacteria such as uropathogenic Escherichia coli (UPEC) has attracted significant attention due to increased MDR properties, even against the last line of antibiotics. Bacteriophage, or simply phage, represents an alternative treatment to antibiotics. However, phage applications still face some challenges, such as host range specificity and development of phage resistant mutants. In this study, using both UPEC and non-UPEC hosts, five different phages were isolated from wastewater. We found that the inclusion of commensal Escherichia coli as target hosts during screening improved the capacity to select phage with desirable characteristics for phage therapy. Whole-genome sequencing revealed that four out of five phages adopt strictly lytic lifestyles and are taxonomically related to different phage families belonging to the Myoviridae and Podoviridae. In comparison to single phage treatment, the application of phage cocktails targeting different cell surface receptors significantly enhanced the suppression of UPEC hosts. The emergence of phage-resistant mutants after single phage treatment was attributed to mutational changes in outer membrane protein components, suggesting the potential receptors recognized by these phages. The findings highlight the use of commensal E. coli as target hosts to isolate broad host range phage with infectivity against MDR bacteria.     

Complete genome sequence of a newly isolated lytic bacteriophage,EFAP‐1 of Enterococcus faecalis,and antibacterial activity of its endolysin EFAL‐1

Aims: In this work, we aimed to identify an effective treatment of infections caused by Enterococcus spp. strains resistant to conventional antibiotics. Methods and Results: We report the isolation and characterization of a new lytic bacteriophage, designated bacteriophage EFAP‐1, that is capable of lysing Enterococcus faecalis bacteria that exhibit resistance to multiple antibiotics. EFAP‐1 has low sequence similarity to all known bacteriophages. Transmission electron microscopy confirmed that EFAP‐1 belongs to the Siphoviridae family. A putative lytic protein of EFAP‐1, endolysin EFAL‐1, is encoded in ORF 2 and was expressed in Escherichia coli. Recombinant EFAL‐1 had broad‐spectrum lytic activity against several Gram‐positive pathogens, including Ent. faecalis and Enterococcus faecium. Conclusions: The complete genome sequence of the newly isolated enterococcal lytic phage was analysed, and it was demonstrated that its recombinant endolysin had broad lytic activity against various Gram‐positive pathogens. Significance and Impact of the Study: Bacteriophage EFAP‐1 and its lytic protein, EFAL‐1, can be utilized as potent antimicrobial agents against Enterococcus spp. strains resistant to conventional antibiotics in hospital infections and also as environmental disinfectants to control disease‐causing Enterococcus spp. in dairy farms.     

Bacteriophage phi297, a new species of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> temperate phages with a mosaic genome: Potential use in phage therapy

The genome of halo-forming temperate Pseudomonas aeruginosa phage phi297 and lytic activity of its virulent mutant were studied. A mosaic structure was revealed for phi297 genome by its complete sequencing. The phi297 genome was partly homologous to the genomes of phages D3 and F116. High lytic activity was assumed for temperate P. aeruginosa bacteriophage phi297 on the basis of morphological features of negative colonies. Virulent mutant phi297vir, which was capable of lysing the wild-type phage bacteria, was isolated. Lytic activity was compared for phi297 and the phages from commercial mixtures of two manufacturers (facilities of Nizhnii Novgorod and Perm’). Phage phi297 caused lysis of the mutant PAO1 bacteria that were resistant to the phages from commercial preparations, but the lytic activity spectrum of phi297 was narrower that the spectra of the commercial phages. The use of nonreverting virulent mutants of certain temperate bacteriophages was proposed for the treatment of P. aeruginosa infections.     

Characterization of a T7-Like Lytic Bacteriophage of <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> B5055: A Potential Therapeutic Agent

Characterization of bacteriophages to be used prophylactically or therapeutically is mandatory, as use of uncharacterized bacteriophages is considered as one of the major reasons of failure of phage therapy in preantibiotic era. In the present study, one lytic bacteriophage, KPO1K2, specific for Klebsiella pneumoniae B5055, with broad host range was selected for characterization. As shown by TEM, morphologically KPO1K2 possessed icosahedral head with pentagonal nature with apex to apex head diameter of about 39 nm. Presence of short noncontractile tail (10 nm) suggested its inclusion into family Podoviridae with a designation of T7-like lytic bacteriophage. The phage growth cycle with a latent period of 15 min and a burst size of approximately 140 plaque forming units per infected cell as well as a genome of 42 kbps and structural protein pattern of this bacteriophage further confirmed its T7-like characteristics. Phage was stable over a wide pH range of 4–11 and demonstrated maximum activity at 37°C. After injection into mice, at 6 h, a high phage titer was seen in blood as well as in kidney and urinary bladder, though titers in kidney and urinary bladder were higher as compared to blood. Phage got cleared completely in 36 h from blood while from kidneys and urinary bladder its clearance was delayed. We propose the use of this characterized phage, KPO1K2, as a prophylactic/therapeutic agent especially for the treatment of catheter associated UTI caused by Klebsiella pneumoniae.     

A cointegrate of the bacteriophage P1 genome and the conjugative R plasmid R100

Restriction cleavage analysis identified a P1CmSmSuTc plasmid isolated by Mise and Arber (1976) (Virology 69, 191–205) as a cointegrate between bacteriophage P1 and the R plasmid R100. Cointegration occurred by reciprocal recombination between the IS1 element of P1 and IS1b of R100. It involved neither gain nor loss of genetic material, so that the cointegrate carries three IS1 elements in the same orientation. The cointegrate propagates with relatively high stability as plasmid in Escherichia coli host bacteria. It displays the Tra⁺ functions of R100, incompatibility FII of R100, and incompatibility Y of P1, Res⁺ (P1), Mod⁺ (P1) functions of P1 and P1 immunity. Production of P1 phage particles is inducible as for wild type P1. However, because of the large genome size of 180 kb, progeny phage particles contain only a fraction (about 100 kb) of the cointegrate genome. Because of cyclic permutation all genome regions are equally represented in a population of the phage particles of an induced lysate. Occasionally, reciprocal recombination between IS1 elements allows the restoration of the P1 genome. These segregants are found as plaque formers at a rate of about 1 per 300 phage particles in induced lysates.     

A novel Pseudomonas aeruginosa Bacteriophage,Ab31, a Chimera Formed from Temperate Phage PAJU2 and P. putida Lytic Phage AF: Characteristics and Mechanism of Bacterial Resistance

A novel temperate bacteriophage of Pseudomonas aeruginosa, phage vB_PaeP_Tr60_Ab31 (alias Ab31) is described. Its genome is composed of structural genes related to those of lytic P. putida phage AF, and regulatory genes similar to those of temperate phage PAJU2. The virion structure resembles that of phage AF and other lytic Podoviridae (S. enterica Epsilon 15 and E. coli phiv10) with similar tail spikes. Ab31 was able to infect P. aeruginosa strain PA14 and two genetically related strains called Tr60 and Tr162, out of 35 diverse strains from cystic fibrosis patients. Analysis of resistant host variants revealed different phenotypes, including induction of pigment and alginate overproduction. Whole genome sequencing of resistant variants highlighted the existence of a large deletion of 234 kbp in two strains, encompassing a cluster of genes required for the production of CupA fimbriae. Stable lysogens formed by Ab31 in strain Tr60, permitted the identification of the insertion site. During colonization of the lung in cystic fibrosis patients, P. aeruginosa adapts by modifying its genome. We suggest that bacteriophages such as Ab31 may play an important role in this adaptation by selecting for bacterial characteristics that favor persistence of bacteria in the lung.     

Regulation of replication of λ phage and λ plasmid DNAs at low temperature

It was previously demonstrated that while lysogenic development of bacteriophage λ in Escherichia coli proceeds normally at low temperature (20–25° C), lytic development is blocked under these conditions owing to the increased stability of the phage CII protein. This effect was proposed to be responsible for the increased stimulation of the p _E promoter, which interferes with expression of the replication genes, leading to inhibition of phage DNA synthesis. Here we demonstrate that the burst size of phage λcIb2, which is incapable of lysogenic development, increases gradually over the temperature range from 20 to 37° C, while no phage progeny are observed at 20° C. Contrary to previous reports, it is possible to demonstrate that p _E promoter activation by CII may be more efficient at lower temperature. Using density-shift experiments, we found that phage DNA replication is completely blocked at 20° C. Phage growth was also inhibited in cells overexpressing cII, which confirms that CII is responsible for inhibition of phage DNA replication. Unexpectedly, we found that replication of plasmids derived from bacteriophage λ is neither inhibited at 20° C nor in cells overexpressing cII. We propose a model to explanation the differences in replication observed between λ phage and λ plasmid DNA at low temperature. Received: 30 December 1997 / Accepted: 25 February 1998     

Yet another way that phage λ manipulates its Escherichia coli host: λrexB is involved in the lysogenic–lytic switch

The life cycle of phage λ has been studied extensively. Of particular interest has been the process leading to the decision of the phage to switch from lysogenic to lytic cycle. The principal participant in this process is the λcI repressor, which is cleaved under conditions of DNA damage. Cleaved λcI no longer acts as a repressor, allowing phage λ to switch from its lysogenic to lytic cycle. The well‐known mechanism responsible for λcI cleavage is the SOS response. We have recently reported that the Escherichia coli toxin‐antitoxin mazEF pathway inhibits the SOS response; in fact, the SOS response is permitted only in E. coli strains deficient in the expression of the mazEF pathway. Moreover, in strains lysogenic for prophage λ, the SOS response is enabled by the presence of λrexB. λRexB had previously been found to inhibit the degradation of the antitoxin MazE, thereby preventing the toxic action of MazF. Thus, phage λ rexB gene not only safeguards the prophage state by preventing death of its E. coli host but is also indirectly involved in the lysogenic–lytic switch.     

Properties of the peptidoglycan-degrading enzyme of the Pseudomonas aeruginosa ϕPMG1 bacteriophage

The ?PMG1 Pseudomonas aeruginosa bacteriophage was isolated. It is characterized by certain peculiarities of the lytic infection cycle and forms a halo (clear zone) around negative colonies. The phage was studied with regard to its potential use in therapeutic phage preparations and as a source of peptidoglycan- and lipopolysacchraide-degrading enzymes. Partial sequencing of the ?PMG1 genome revealed a high degree of homology with the D3 moderate bacteriophage. An open reading frame coding for a lytic transglycosylase has been identified in ?PMG1 genome. The enzyme has been obtained in a recombinant form, and its activity and substrate specificity have been characterized.     

Isolation and Partial Characterization of a Virulent Bacteriophage IHQ1 Specific for Aeromonas punctata from Stream Water

Aeromonas punctata is the causative agent of septicemia, diarrhea, wound infections, meningitis, peritonitis, and infections of the joints, bones and eyes. Bacteriophages are often considered alternative agents for controlling bacterial infection and contamination. In this study, we described the isolation and preliminary characterization of bacteriophage IHQ1 (family Myoviridae) active against the Gram-negative bacterial strain A. punctata. This virulent bacteriophage was isolated from stream water sample. Genome analysis indicated that phage IHQ1 was a double-stranded DNA virus with an approximate genome size of 25–28 kb. The initial characterization of this newly isolated phage showed that it has a narrow host range and infects only A. punctata as it failed to infect seven other clinically isolated pathogenic strains, i.e., methicillin-resistant Staphylococcus aureus 6403, MRSA 17644, Acinetobacter 33408, Acinetobacter 1172, Pseudomonas aeruginosa 22250, P. aeruginosa 11219, and Escherichia coli. Proteomic pattern of phage IHQ1, generated by SDS-PAGE using purified phage particles, showed three major and three minor protein bands with molecular weights ranging from 25 to 70 kDa. The adsorption rate of phage IHQ1 to the host bacterium was also determined, which was significantly enhanced by the addition of 10 mM CaCl₂. From the single-step growth experiment, it was inferred that the latent time period of phage IHQ1 was 24 min and a burst size of 626 phages per cell. Moreover, the pH and thermal stability of phage IHQ1 were also investigated. The maximum stability of the phage was observed at optimal pH 7.0, and it was totally unstable at extreme acidic pH 3; however, it was comparatively stable at alkaline pH 11.0. At 37°C the phage showed maximum number of plaques, and the viability was almost 100%. The existence of Aeromonas bacteriophage is very promising for the eradication of this opportunistic pathogen and also for future applications such as the design of new detection and phage typing (diagnosis) methods. The specificity of the bacteriophage for A. punctata makes it an attractive candidate for phage therapy of A. punctata infections.     

Properties of the endolytic transglycosylase encoded by gene 144 of Pseudomonas aeruginosa bacteriophage phiKZ

Bacteriophage endolysins degrading bacterial cell walls are prospective enzymes for therapy of bacterial infections. The genome of the giant bacteriophage phiKZ of Pseudomonas aeruginosa encodes two endolysins, gene products (g.p.) 144 and 181, which are homologous to lytic transglycosylases. Gene 144 encoding a 260 amino acid residue protein was cloned into the plasmid expression vector. Recombinant g.p. 144 purified from Escherichia coli effectively degrades chloroform-treated P. aeruginosa cell walls. The protein has predominantly α-helical conformation and exists in solution in stoichiometric monomer: dimer: trimer equilibrium. Antibodies against the protein bind the phage particle. This demonstrates that g.p. 144 is a structural component of the phiKZ particle, presumably, a phage tail. Published in Russian in Biokhimiya, 2006, Vol. 71, No. 3, pp. 379–385.     

Stability and activity of an<Emphasis Type="Italic"> Enterobacter aerogenes</Emphasis>-specific bacteriophage under simulated gastro-intestinal conditions

A bacteriophage, designated UZ1 and showing lytic activity against a clinically important strain (BE1) of Enterobacter aerogenes was isolated from hospital sewage. The stability and lytic activity against this strain under simulated gastro-intestinal conditions was evaluated. After addition of bacteriophage UZ1 to a liquid feed at gastric pH 2, the phage was immediately inactivated and could not be recovered. However, by use of an antacid to neutralize stomach acidity, no significant changes in phage titer were observed after 2 h incubation at 37 °C. After supplementing pancreatic juice and further incubation for 4 h, the phage titer remained stable. The persistence of UZ1 in a mixed microbial ecosystem that was representative for the large intestine was monitored using an in vitro simulation of the human intestinal microbial ecosystem. A pulse administration of bacteriophage UZ1 at a concentration of 10⁵ plaque-forming units (PFU)/ml to reactor 3 (which simulates the ascending colon) showed that, in the absence of the host, bacteriophage UZ1 persisted for 13 days in the simulated colon, while the theoretical washout was calculated at 16 days. To assess its lytic activity in an intestinal microbial ecosystem, a green fluorescent protein (gfp)-labeled E. aerogenes BE1 strain was constructed and gfp-specific primers were designed in order to quantify the host strain using real-time PCR. It was observed that bacteriophage UZ1 was able to replicate and showed lytic activity against E. aerogenes BE1/gfp in an intestinal microbial ecosystem. Indeed, after 17 h a 2 log unit reduction of E. aerogenes BE1/gfp was measured as compared with the assay without bacteriophage UZ1, while the phage titer increased by 2 log units at an initial multiplicity of infection of 0.07 PFU/colony-forming unit. This is the first report of an in vitro model to study bacteriophage activity in the complex intestinal microbial community.     

Environmental Factors that influence the Transition from Lysogenic to Lytic Existence in the ϕHSIC/Listonella pelagia Marine Phage–Host System

The marine phage ϕHSIC has been previously reported to enter into a pseudolysogenic-like interaction with its host Listonella pelagia. This phage–host system displays behaviors that are characteristic of both pseudolysogeny and lysogeny including a high rate of spontaneous induction and chromosomal integration of the prophage. To determine what parameters may influence the transition from lysogenic to lytic existence in the ϕHSIC/L. pelagia phage–host system, cultures of this organism were incubated under different environmental conditions, while host cell growth and bacteriophage production were monitored. The environmental parameters tested included salinity, temperature, a rapid temperature shift, and degree of culture aeration. The highest titers of phage were produced by HSIC-1a cells grown in high-salinity nutrient artificial seawater media (67 ppt with a natural salinity equivalent of 57 ppt) or those cultured in highly aerated nutrient artificial seawater media (cultures shaken at 300 rpm). Conversely, the lowest titers of phage were produced under low salinity or rate of aeration. In general, conditions that stimulated growth resulted in greater lytic phage production, whereas slow growth favored lysogeny. These results indicate that elevated salinity and aeration influenced the switch from lysogenic to lytic existence for the phage ϕHSIC. These results may have implications for environmental controls of the lysogenic switch in natural populations of marine bacteria.     

Rapid label-free detection of E. coli using a novel SPR biosensor containing a fragment of tail protein from phage lambda

Abstract

In efforts to speed up the assessment of microorganisms, researchers have sought to use bacteriophages as a biosensing tool, due to their host-specificity, wide abundance, and safety. However, the lytic cycle of the phage has limited its efficacy as a biosensor. Here, we cloned a fragment of tail protein J from phage lambda and characterized its binding with the host, E. coli K-12, and other microorganism. The N-terminus of J was fused with a His-tag (6HN-J), overexpressed, purified, and characterized using anti-His monoclonal antibodies. The purified protein demonstrated a size of ～38?kDa upon SDS-PAGE and bound with the anti-His monoclonal antibodies. ELISA, dot blot, and TEM data revealed that it specifically bound to E. coli K-12, but not to Pseudomonas aeruginosa. The observed protein binding occurred over a concentration range of 0.01–5?μg/ml and was found to inhibit the in vivo adsorption of phage to host cells. This specific binding was exploited by surface plasmon resonance (SPR) to generate a novel 6HN-J-functionalized SPR biosensor. This biosensor showed rapid label-free detection of E. coli K-12 in the range of 2?×?10⁴ ?2?×?10⁹ CFU/ml, and exhibited a lower detection limit of 2?×?10⁴ CFU/ml.     

一株新型牛源肺炎克雷伯菌噬菌体的分离鉴定

【背景】肺炎克雷伯菌(Klebsiella pneumoniae)是一种广泛分布于环境中的重要致病菌,该菌较高的耐药性致其在养殖业中治疗较为困难。【目的】分离一株裂解性肺炎克雷伯菌噬菌体,对分离株进行生物学特性鉴定和基因组学分析。【方法】使用双层平板法从四川省某奶牛场中分离、纯化出一株裂解性噬菌体,测定其裂解谱、热稳定性、酸碱耐受度、最佳感染复数及一步生长曲线等生物学特性,并进行全基因组的测序及注释分析。【结果】得到一株裂解性肺炎克雷伯菌噬菌体vB_Kpn_B01,该噬菌体拥有透明且无晕环的噬菌斑,热稳定性较高,在极酸或极碱环境下不进行裂解活动,特异性较强,属长尾噬菌体科(Siphoviridae)。vB_Kpn_B01全基因组大小为113 227 bp,GC含量为47.97%。注释结果显示噬菌体拥有149个编码序列和25个tRNAs,不含耐药基因及毒力基因。通过噬菌体的进化树分析发现,该噬菌体为Sugarlandvirus。【结论】vB_Kpn_B01拥有高效的生长特性和对不利环境的低耐受性,拥有裂解宿主菌的必备基因,并不含耐药基因及毒力基因,具有应用于畜牧业中防治多重耐药细菌的潜力。     

PHENOTYPIC STOCHASTICITY PROTECTS LYTIC BACTERIOPHAGE POPULATIONS FROM EXTINCTION DURING THE BACTERIAL STATIONARY PHASE

It is generally thought that the adsorption rate of a bacteriophage correlates positively with fitness, but this view neglects that most phages rely only on exponentially growing bacteria for productive infections. Thus, phages must cope with the environmental stochasticity that is their hosts’ physiological state. If lysogeny is one alternative, it is unclear how strictly lytic phages can survive the host stationary phase. Three scenarios may explain their maintenance: (1) pseudolysogeny, (2) diversified, or (3) conservative bet hedging. To better understand how a strictly lytic phage survives the stationary phase of its host, and how phage adsorption rate impacts this survival, we challenged two strictly lytic phage λ, differing in their adsorption rates, with stationary phase Escherichia coli cells. Our results showed that, pseudolysogeny was not responsible for phage survival and that, contrary to our expectation, high adsorption rate was not more detrimental during stationary phase than low adsorption rate. Interestingly, this last observation was due to the presence of the “residual fraction” (phages exhibiting extremely low adsorption rates), protecting phage populations from extinction. Whether this cryptic phenotypic variation is an adaptation (diversified bet hedging) or merely reflecting unavoidable defects during protein synthesis remains an open question.